Evaporative fuel vapor emission control system

Abstract

This application relates to an evaporative fuel vapor emission control system. Specifically, the present disclosure describes an evaporative emission control canister system that includes: one or more canisters, the one or more canisters including at least one vent-side particulate adsorbent volume that includes a particulate adsorbent having: micropores with a diameter of less than about 100 nm; macropores with a diameter of about 100 to 100,000 nm; a ratio of the volume of the macropores to the volume of the micropores that is greater than about 150%, and having a retention rate of 1.0 g / dL or less. The system may also include a high butane working capacity adsorbent. The present disclosure also describes a method for reducing emissions in an evaporative emission control system.

Description

[0001] This application is a divisional application of Chinese Patent Application No. 201880040804.0, with an application date of June 19, 2018 and an invention title of "Evaporative Fuel Vapor Emission Control System".

[0002] Cross - reference to related applications

[0003] This application claims the priority of U.S. Provisional Patent Application 62 / 521,912 filed on June 19, 2017 and U.S. Provisional Patent Application 62 / 685,174 filed on June 14, 2018, the entire disclosures of which are incorporated herein by reference for all purposes. Technical field

[0004] The present disclosure generally relates to a system including a particulate adsorbent material and a method of using the same. More specifically, the present disclosure relates to a system including a low - retention particulate adsorbent material and a method of using the low - retention particulate adsorbent material in an evaporative fuel vapor emission control system. Background art

[0005] Evaporation of gasoline fuel from a motor vehicle fuel system is a major source of hydrocarbon air pollution. Such emissions can be controlled by a canister system that employs activated carbon to adsorb fuel vapors generated by the fuel system. During certain engine operating modes, the canister system is purged with ambient air to desorb fuel vapors from the activated carbon, thereby periodically removing the adsorbed fuel vapors from the activated carbon. The regenerated carbon is then ready to adsorb additional fuel vapors.

[0006] The increasing environmental concerns continue to drive the implementation of strict regulations on hydrocarbon emissions from motor vehicles, even when the vehicles are not in operation. When a vehicle is parked, the vapor pressure in the vehicle's fuel tank increases with the rise in ambient temperature. Typically, to prevent fuel vapor from leaking from the vehicle into the atmosphere, the fuel tank is connected by a conduit to a canister containing a suitable fuel adsorbent material that can temporarily adsorb the fuel vapor. A mixture of fuel vapor and air from the fuel tank enters the canister through the fuel vapor inlet of the canister and then expands or diffuses into the adsorbent volume, where the fuel vapor is temporarily stored, and the purified air is released to the atmosphere through the vent of the canister. Once the engine is started, ambient air is drawn into the canister system through the vent of the canister via manifold vacuum. The purge air flows through the adsorbent volume inside the canister and desorbs the fuel vapor adsorbed on the adsorbent volume, which then enters the internal combustion engine through the fuel vapor purge conduit. The purge air cannot desorb all of the fuel vapor adsorbed on the adsorbent volume, resulting in residual hydrocarbons ("residue") that may be emitted into the atmosphere. Additionally, the residue that is in local equilibrium with the gas phase also allows fuel vapor from the fuel tank to migrate through the canister system as an emission. This emission typically occurs when the vehicle is parked and experiences diurnal temperature variations over a period of several days and is commonly referred to as "diurnal breathing loss".

[0007] In the United States, the California Low-Emission Vehicle Regulation requires that for many vehicles starting from the 2003 model year, the daytime breathing loss (DBL) emissions of the canister system be less than approximately 20 mg ("PZEV"); for a large number of vehicles starting from the 2004 model year, the daytime breathing loss emissions be less than approximately 50 mg ("LEV-II"). Now, the California Low-Emission Vehicle Regulation (LEV-III) and the EPA Tier 3 standards require that the canister DBL emissions not exceed 20 mg. According to the California Evaporative Emissions Standards and Test Procedures for 2001 and Subsequent Model Motor Vehicles, the Bleed Emissions Test Procedure (BETP) written on March 22, 2012, and the EPA Control of Air Pollution From Motor Vehicles: Tier 3 Motor Vehicle Emission and Fuel Standards; Final Rule, 40 CFR Parts 79, 80, 85, etc. Globally, in contrast, the requirements of evaporative emission regulations are not as strict as those in the United States, but the current trend is to develop more stringent regulations along the lines taken in the United States. There is a growing recognition that stricter controls are beneficial for better vehicle fuel use and cleaner air, especially in regions where the rapid growth in light vehicle use and air quality problems urgently require attention.

[0008] To meet evaporative fuel emission regulatory standards during the vehicle design phase, vehicle manufacturers typically provide target specifications for overall canister system performance to potential suppliers, including functional contents, appearance, physical properties, and durability, thus allowing appropriate design flexibility for canister system manufacturers to achieve these goals. For example, General Motors has set numerous design specifications for evaporative emission control canister systems (see GMW16494). One notable specification is the total allowable pressure drop of the charcoal canister system. In this instance, the maximum flow restriction for a canister system used for on-board refueling vapor recovery (ORVR) "shall be 0.90 ± 0.225 kPa at an air flow rate of 60 liters per minute (lpm) …… as measured at the tank outlet when air flows from the tank outlet pipe to the fresh air pipe" (see Section 3.2.1.3.2.2 of GMW-16494). This specification and other specifications in GMW-16494 provide examples of the degree of flow restriction allowed by vehicle manufacturers.

[0009] Due to such specifications, canister system designers consider a wide variety of adsorbent options because, in addition to different fuel emission regulations around the world, different vehicle platforms from different vehicle manufacturers also have very different requirements for engine type, engine operating design, space availability, purge availability, and canister system control strategies. Of course, for canister system design and its adsorbent filling, "one size does not fit all". Therefore, there is an urgent need for new adsorbent options and methods that balance trade-offs in terms of cost, size, flow restriction, working capacity, diurnal breathing loss (DBL) performance, complexity, and placement flexibility.

[0010] For example, several methods involving chamber design and adsorbent properties for reducing DBL emissions have been reported, which is one of the aspects of the specifications that the canister system must meet.

[0011] One way to achieve low emissions is to significantly increase the volume of the purge gas to enhance the desorption of residual hydrocarbon residues from the adsorbent volume. However, the drawback of this method is that it complicates the management of the fuel / air mixture for the engine during the purge step and tends to adversely affect tailpipe emissions. See U.S. Patent No. 4,894,072. For certain high-performance and high fuel efficiency engine designs, including turbocharged, gasoline direct injection, and hybrid vehicles, this high purge is not available or may greatly affect engine performance.

[0012] Another method is to design the canister to have a relatively small cross-sectional area on the vent side of the canister by re-designing existing canister sizes or by installing appropriately sized supplementary vent side canister chambers. See U.S. Patent No. 5,957,114. This method reduces residual hydrocarbon residues by increasing the intensity of the purge air. A disadvantage of this method is that for conventional particulate adsorbents in solid shapes with diameters of 1 to 3 mm, the relatively low cross-sectional area imposes excessive flow restrictions on the canister, except in the case of the shortest bed length, but in this case the effectiveness of the vent side chamber for DBL emission control will be impaired in other ways. Thus, although it may be effective in reducing the bleed emissions of the system, conventional particulate adsorbents cannot accommodate excessive flow restrictions.

[0013] Another way to improve purge efficiency is to heat the purge air or the portion of the adsorbent volume that has adsorbed fuel vapor or both. See U.S. Patent Nos. 6,098,601 and 6,279,548. However, this method increases the complexity of the control system management and poses some safety hazards.

[0014] Another method is to select a variety of adsorbents in the canister system chamber, such as, before discharging to the atmosphere, guiding the fuel vapor through one or more fuel side adsorbent volumes that are proximal or near the fuel side orifice of the canister system (i.e., upstream in the fluid or vapor path), and then guiding it to at least one vent side or subsequent adsorbent volume that is downstream (or distal) in the fluid or vapor path relative to the fuel side adsorbent, wherein the initial adsorbent volume has a higher incremental adsorption capacity than the subsequent adsorbent volume (the slope of the butane adsorption isotherm is greater between 5% and 50% concentration). See U.S. Patent No. RE38,844 and U.S. Patent No. 9,732,649, the entire disclosures of which are incorporated herein by reference.

[0015] An effective form of the subsequent adsorbent volume towards the vent side of the canister system is an elongated ceramic-bonded activated carbon honeycomb, such as HCA( North Charleston, South Carolina, USA), and diameters of 29, 35, and 41 mm and specific lengths between 50 and 200 mm are typically available. Although this adsorbent structure provides the desired adsorption properties with low flow restrictions, these engineered parts are costly to manufacture, require special skills and equipment to manufacture, and the direct initial customers, i.e., the designers of the canister system, are limited to honeycomb parts in those sizes that are typically available for system design, testing, and certification.

[0016] An alternative effective form of the vent side volume that allows chamber design flexibility is in the form of 2 to 3 mm pellets, such as BAX LBE activated carbon ( North Charleston, South Carolina, USA) or 2GK-C7 activated carbon (Kuraray Chemical Co., Ltd., Bizen City, Japan). Although these pellets may have useful adsorption properties for purge emission control and, as particulate materials, allow great flexibility in the sizing of the adsorbent chambers in which these pellets are filled, these pellets have high flow restriction properties relative to carbon honeycombs, which limits potentially useful smaller cross-sectional area geometries as taught in U.S. Patent No. 5,957,114.

[0017] Following the concept of a series adsorbent, when operating under low volume purges, such as for "hybrid" vehicles where the internal combustion engine is shut off for nearly half of the vehicle operation time and where the purge frequency is much lower than normal, an adsorbent volume having a graded adsorption working capacity (e.g., butane working capacity (BWC) and total grams butane working capacity) on the vent side of the system is taught to be particularly useful for an evaporative emission canister system. See WO 2014 / 059190 (PCT / US2013 / 064407). Other engine designs that pose challenges to canister purging include gasoline direct injection and turbocharging or turbo-assisted features. However, these methods are generally limited to the form of carbon honeycombs.

[0018] The challenges and desires described in the above methods and other aspects (see, for example, U.S. Patent Nos. 7,186,291 and 7,305,974) are to reduce the harmful effects of residual adsorbed vapors on the performance of the evaporative emission canister system, especially the DBL emission performance, where it is highly desirable to achieve the lowest amount of residual adsorbed vapors (lowest amount of residue). In addition, it is known that the deterioration of the DBL emission performance and working capacity performance of the canister system (also known as "aging") is also due to the accumulation of less purgeable components in this adsorbed vapor residue (see, for example, SAE Technical Paper Series 2000-01-895). Thus, the benefits of low retention of hydrocarbons after purging are twofold: lower levels of DBL emissions for new vehicles and the maintenance of working capacity and emission performance provided by low vapor retention properties throughout the life of the vehicle.

[0019] While highly desirable as a method, the combination of low cost, low production complexity, high material structural strength, low flow restriction, and minimal vapor retention by particulate adsorbents for evaporative emissions control is considered an almost insurmountable design challenge. For example, as taught by U.S. Patent No. 9,174,195 (“the ‘195 patent”), the useful range of the ratio of the macroscopic “M” pore volume to the microscopic “m” pore volume is limited to between 65% and 150% M / m because mechanical strength fails at higher ratios. Additionally, within the required pore ratio range, the vapor retention (retention rate) progressively exceeds 1 g / dL, which is the butane residue measured by a standard ASTM test, and when the pore ratio exceeds the required 150% limit, (in addition to poor strength) the vapor retention rate exceeds the stated 1.7 g / dL target. It should be noted that the ‘195 patent teaches that for a typical 5 mm diameter pellet, having an M / m pore ratio in excess of 150% is not robust enough for use (see Figure 6 ). The 2GK-C7 pellet adsorbent material (Kuraray Chemical Co., Ltd., Bizen City, Japan) highlights the trade-off between pore ratio and pellet strength, although the pellet adsorbent material has an M / m of approximately 170% and an average diameter of 2.6 mm, which has the undesirable effect of increasing flow restriction while improving strength. In other words, although it has the function of controlling emissions, the ‘195 patent teaches that the relatively high M / m ratio of 2GK-C7 is not suitable for larger diameter pellets, which will also weaken strength while providing lower flow restriction and having a high retention rate.

[0020] Accordingly, there remains a need for additional adsorbent options for designers of evaporative emissions control systems, particularly for the adsorbent volume towards the vent side, which is robust but also exhibits low vapor retention and low flow restriction, which contributes to achieving high working capacity and low DBL emissions performance through the system over the life of the vehicle. SUMMARY OF THE INVENTION

[0021] Described herein is an evaporative emission control canister system having surprising and unexpected properties, including less than about 50 mg or less than about 20 mg of two-day diurnal breathing loss (DBL) emissions, including in cases having a relatively low purge volume (e.g., less than about 175 BV or less than 100 BV). It has surprisingly and unexpectedly been found that low purge and low DBL evaporative emission control canister systems can be achieved using the particulate adsorbent volumes described herein, which are low in manufacturing cost, have a desired retention rate, have a high material structural strength, and have a low flow restriction. For example, the particulate adsorbent material providing the low DBL canister system described herein has a ratio of macroporosity (M) to microporosity (m) (i.e., M / m) higher than 150%, a butane retention rate lower than 1.0 g / dL, while also being large enough and strong enough to be used in the system without imposing an excessive flow restriction.

[0022] Accordingly, in one aspect, the present disclosure provides an evaporative emission control canister system comprising: one or more canisters having a plurality of chambers, each chamber defining a volume, the plurality of chambers being in fluid communication to allow fluid (e.g., air, gas, or fuel vapor) to flow directionally from one chamber to the next, wherein at least one chamber includes at least one particulate adsorbent volume, the at least one particulate adsorbent volume including a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 nm to 100,000 nm, and a ratio of the volume of macropores to the volume of micropores greater than about 150%, and wherein the particulate adsorbent volume has a flow restriction property of less than 40 Pa / cm under conditions of applying an apparent linear air velocity of 46 cm / s to a 43 mm diameter bed of the particulate adsorbent material, or a flow restriction of less than 0.3 kPa at an air flow rate of 40 lpm, or both. In certain embodiments, the particulate adsorbent volume has a length-to-diameter ratio of 2 or greater, a butane retention rate of <1.0 g / dL, or a combination thereof. In certain embodiments, the butane retention rate <0.5 g / dL. In certain embodiments, the evaporative emission control canister system includes at least one fuel-side adsorbent volume, at least one vent-side post-adsorbent volume, or both. In certain embodiments, the adsorbent volume is located within a single canister or within multiple canisters that are connected to allow sequential contact by fuel vapor. In certain embodiments, the at least one particulate adsorbent volume, the at least one fuel-side adsorbent volume, or both have: a nominal butane working capacity (BWC) of at least 8 g / dL (e.g., at least 10 g / L); a nominal incremental adsorption capacity (IAC) at 25° C. of at least 35 g / L between vapor concentrations of 5 vol % and 50 vol % n-butane; or both. In certain embodiments, the at least one particulate adsorbent volume, the at least one vent-side post-adsorbent volume, or both have: a nominal BWC of less than 8 g / dL; a nominal IAC at 25° C. of less than 35 g / L between vapor concentrations of 5 vol % and 50 vol % n-butane; or both. In certain embodiments, the particulate volume has an M / m ratio greater than about 200%.

[0023] In another aspect, the present specification provides an evaporative emission control canister system that includes one or more canisters, the one or more canisters including at least one fuel side adsorbent volume (i.e., an adsorbent volume at or near the fuel tank vapor inlet) and at least one vent side particulate adsorbent volume. In certain embodiments, the at least one vent side particulate adsorbent volume is included as an alternative to or in combination with one or more vent side subsequent adsorbent volumes. The at least one fuel side adsorbent volume, the at least one vent side particulate adsorbent volume, and / or the at least one vent side subsequent adsorbent volume may be contained in a single canister or separate canisters that are connected to allow sequential contact by fuel vapor (and conversely, purge air). In certain embodiments, the at least one vent side subsequent adsorbent volume includes a non-particulate adsorbent material such as foam, monolith, polymer, or paper sheet or honeycomb (e.g., activated carbon honeycomb), where the at least one vent side subsequent adsorbent volume imposes a low vapor or fluid flow restriction.

[0024] In certain embodiments, the evaporative emission control canister system includes: at least one vent side subsequent adsorbent volume upstream of the at least one vent side particulate adsorbent volume (i.e., located in the fluid path closer to the fuel side adsorbent volume or the fuel vapor inlet), at least one vent side subsequent adsorbent volume downstream of the at least one vent side particulate adsorbent volume (i.e., located in the fluid path closer to the vent), or a combination thereof.

[0025] In certain embodiments, the evaporative emission control canister system includes: at least one vent side particulate adsorbent volume upstream of the at least one vent side subsequent adsorbent volume (i.e., located in the fluid path closer to the fuel side adsorbent volume or the fuel vapor inlet), at least one vent side particulate adsorbent volume downstream of the at least one vent side subsequent adsorbent volume (i.e., located in the fluid path closer to the vent), or a combination thereof.

[0026] In any aspect or embodiment described herein, the at least one vent side subsequent adsorbent volume includes a non-particulate adsorbent material such as foam, monolith, honeycomb, polymer, or paper sheet. In certain embodiments, the non-particulate adsorbent material imposes a low vapor or fluid flow restriction. In certain embodiments, the non-particulate adsorbent material is a honeycomb having a uniform cross-sectional area.

[0027] The adsorbent for use in the adsorbent volume can be derived from many different materials and various forms. It can be a single component or a mixture of different components. Additionally, the adsorbent (as a single component or a mixture of different components) may include a volume diluent. Non-limiting examples of volume diluents can include, but are not limited to, spacers, inert gaps, foams, fibers, springs, or combinations thereof.

[0028] In any aspect or embodiment described herein, any known adsorbent material can be used for the fuel-side adsorbent volume, the vent-side particulate adsorbent volume, and the vent-side subsequent adsorbent volume. The adsorbent materials include, but are not limited to, activated carbon, charcoal, zeolite, clay, porous polymers, porous alumina, porous silica, molecular sieves, kaolin, titanium dioxide, cerium dioxide, or combinations thereof. Activated carbon can be derived from various carbon precursors. As non-limiting examples, the carbon precursors can be wood, wood chips, wood powder, cotton linters, peat, coal, coconut, lignite, carbohydrates, petroleum pitch, petroleum coke, coal tar pitch, fruit pits, fruit stones, nut shells, nut kernels, sawdust, palm, vegetables such as rice husks or straw, synthetic polymers, natural polymers, lignocellulosic materials, or combinations thereof. Additionally, various processes including, but not limited to, chemical activation, thermal activation, or combinations thereof can be used to produce activated carbon.

[0029] In any aspect or embodiment described herein, any of a variety of adsorbent forms can be used for the fuel-side adsorbent volume, the vent-side particulate adsorbent volume, and the vent-side subsequent adsorbent volume. Non-limiting examples of adsorbent forms can include granular, pellet, spherical, honeycomb, monolithic, pill-shaped cylinders, uniformly shaped particulate media, non-uniformly shaped particulate media, extruded forms of structured media, wound forms of structured media, folded forms of structured media, pleated forms of structured media, corrugated forms of structured media, cast forms of structured media, bonded forms of structured media, non-woven fabrics, woven fabrics, sheets, paper, foams, or combinations thereof. The adsorbent (as a single component or a mixture of different components) can include a volume diluent. Non-limiting examples of volume diluents can include, but are not limited to, spacers, inert voids, foams, fibers, springs, or combinations thereof. Additionally, the adsorbent can be extruded into a special thin-walled cross-sectional shape, such as a hollow cylinder, star, twisted helix, asterisk, configured strip, or other shapes within the capabilities of those skilled in the art. In forming, inorganic and / or organic binders can be used.

[0030] The honeycomb adsorbent can be of any geometric shape, including but not limited to circular, cylindrical, or square. Additionally, the cell openings of the honeycomb adsorbent can have any geometric shape. A honeycomb with a uniform cross-sectional area for the flow channels (such as a square honeycomb with square cross-sectional cell openings or a helically wound honeycomb in a corrugated form) can perform better than a circular honeycomb with square cross-sectional cell openings in a right-angle matrix, which provides a range of cross-sectional areas for adjacent channels and thus provides channels that are not equally purged. Without being bound by any theory, it is believed that the more uniform the cross-sectional area of the cell openings on the honeycomb surface, the more uniform the flow distribution within the component during both the adsorption and purge cycles, and thus the lower the DBL emissions from the canister system.

[0031] In some embodiments, the evaporative emissions control system may further include one or more heat input units for heating one or more adsorbent volumes and / or one or more void volumes. The heat input units may include, but are not limited to, internal resistance elements, external resistance elements, or heat input units associated with the adsorbent. The heat input unit associated with the adsorbent may be an element separate from the adsorbent (i.e., not in contact with the adsorbent). Alternatively, the heat input unit associated with the adsorbent may be a substrate or layer to which the adsorbent is attached, adhered, non-adhered, or in physical contact. The heat input unit associated with the adsorbent may be an adsorbent directly heated by having an appropriate resistivity. The resistivity characteristics of the adsorbent may be altered by adding conductive or resistive additives and binders during the original preparation of the adsorbent and / or during forming the adsorbent into particulate or monolithic form. The conductive component may be a conductive adsorbent, a conductive substrate, a conductive additive, and / or a conductive binder. The conductive material may be added during adsorbent preparation, during an intermediate forming process, and / or during forming the adsorbent into its final form. Any mode of heat input unit may be used. As a non-limiting example, the heat input unit may include a heat transfer fluid, a heat exchanger, a heat conducting element, and a positive temperature coefficient material. The heat input unit may be uniform or non-uniform (i.e., providing different local intensities) along the length of the heated fluid path. Additionally, the heat input unit may or may not be distributed to have greater intensity and heating duration at different points along the length of the heated fluid path.

[0032] In certain embodiments, the downstream adsorbent volume on the vent side is a charcoal monolith or a charcoal honeycomb and is located upstream of the particulate adsorbent volume on the vent side, downstream of the particulate adsorbent volume on the vent side, or a combination thereof, with respect to the position in the fuel vapor path.

[0033] In certain embodiments, the at least one fuel side adsorbent volume has at least one of the following: a relatively high butane working capacity (BWC); an effective incremental adsorption capacity greater than about 35 grams of n-butane per liter (g / L) between vapor concentrations of 5 vol% and 50 vol% n-butane; or both. For example, in certain embodiments, the system further includes at least one additional high butane working capacity (BWC) adsorbent volume that is upstream or before the vent side particulate adsorbent volume (i.e., the high butane working capacity adsorbent volume contacts the fuel vapor before the vent side particulate adsorbent volume when the vehicle is stationary). In certain embodiments, the fuel side adsorbent volume has at least one of the following: i) a relatively high butane working capacity (BWC), e.g., greater than 8, 9, 10, 11, 12, 13, 14, 15, or more grams per deciliter (g / dL); ii) an incremental adsorbent capacity greater than 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, or more grams of n-butane per liter (g / L) between vapor concentrations of 5 vol% and 50 vol% n-butane; or both.

[0034] In certain embodiments, the evaporative emissions control canister system includes at least one vent side particulate adsorbent volume (i.e., downstream of the at least one fuel side adsorbent volume in the vapor path from the fuel tank to the vent). In certain embodiments, the at least one vent side particulate adsorbent volume has a low butane retention rate, a relatively high ratio of macropore volume to micropore volume (M / m), and relatively low flow restriction properties. In certain embodiments, a particulate adsorbent having a low butane retention rate and low flow restriction properties has micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, and a ratio of macropore volume to micropore volume (M / m) greater than about 150%, 160%, 170%, 180%, 190%, 200%, 210%, or 220% or greater, where the particulate adsorbent material has a retention rate of about 1.0 g / dL or less or a flow restriction of less than 40 Pa / cm pressure drop at an apparent linear gas velocity of 46 cm / s.

[0035] In any aspect or embodiment described herein, the vent side particulate adsorbent volume has a flow restriction of less than about 0.3 kPa at an air flow rate of 40 lpm.

[0036] In any aspect or embodiment described herein, the at least one vent side particulate adsorbent volume has a length to diameter ratio of about 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, or greater. In certain embodiments, the vent side particulate adsorbent volume is elongated, having a length to diameter ratio L / D greater than 2.

[0037] In certain embodiments, the M / m of the at least one vent-side particulate adsorbent volume is greater than 150%, and has a flow-limiting property with a pressure drop of less than 40 Pa / cm at an apparent linear air velocity of 46 cm / s. In certain embodiments, the M / m of the vent-side particulate adsorbent volume is greater than 200% and has a butane retention rate of less than 1 g / dL. In certain embodiments, the M / m of the vent-side particulate adsorbent volume is greater than 150% and the butane retention rate is less than 0.5 g / dL.

[0038] In certain embodiments, the evaporative emission control canister system includes at least one vent-side particulate adsorbent volume as described herein, e.g., having a relatively low butane retention rate and low flow restriction, wherein, as determined by the California Bleed Emission Test Procedure (BETP), with a purge of no more than about 175, 150, 125, 120, 115, 110, 100 or fewer bed volumes, or with a purge of less than 315, 300, 275, 250, 225, 200, 175, 150 or fewer liters, the canister system has a two-day DBL emission of no more than about 50, 45, 40, 35, 30, 25, 20 mg or less. In certain embodiments, the evaporative emission control canister system includes at least one adsorbent volume having a low butane retention rate and a low-flow restriction particulate adsorbent, and in the BETP test, with a purge of less than 100 bed volumes or with a purge of less than 210 liters, has a Day 2 DBL emission of no more than 50 mg or no more than 20 mg.

[0039] In some embodiments, the system includes a plurality of vent-side particulate adsorbent volumes configured to allow sequential contact by a fluid such as fuel vapor. In certain embodiments, e.g., the adsorbents are connected in series, thereby defining a fluid flow path therethrough.

[0040] In certain embodiments, the system includes a plurality of canisters connected to allow sequential contact by a fluid such as fuel vapor.

[0041] In other embodiments, the system further includes a subsequent adsorbent volume as described herein, which is located downstream or subsequent to the vent-side particulate adsorbent volume (i.e., when the engine is stationary, the subsequent adsorbent volume contacts the fuel vapor after the fuel vapor encounters the vent-side particulate adsorbent volume).

[0042] In certain embodiments, the at least one subsequent adsorbent volume has at least one of the following: i) a BWC of less than about 8 g / dL, ii) an IAC of less than about 35 g of n-butane / L at a vapor concentration of between 5 vol% and 50 vol% n-butane, or iii) a combination thereof. In certain embodiments, the subsequent adsorbent volume is an active honeycomb.

[0043] In another aspect, the present specification provides an evaporative emission control canister system including one or more canisters, the one or more canisters including: at least one fuel-side adsorbent volume including a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, a ratio of the volume of macropores to the volume of micropores greater than about 150%, and a retention rate of less than about 1.0 g / dL; and at least one vent-side particulate adsorbent volume including a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, a ratio of the volume of macropores to the volume of micropores greater than about 150%, wherein the at least one vent-side particulate adsorbent volume has a butane retention rate of less than 1.0 g / dL. In certain embodiments, when an apparent linear air velocity of 46 cm / s is applied to a 43 mm diameter bed of the vent-side particulate adsorbent volume, the vent-side particulate adsorbent volume has a flow restriction property of less than 40 Pa / cm. In further embodiments, the at least one vent-side particulate adsorbent volume has a flow restriction of less than 0.3 kPa at an air flow rate of 40 lpm. In further embodiments, the vent-side particulate adsorbent volume has a length-to-diameter ratio of 2 or greater. In further embodiments, the at least one fuel-side adsorbent volume has: a nominal BWC of greater than 8 g / dL; a nominal IAC at 25° C. of greater than 35 g / L at a vapor concentration of between 5 vol% and 50 vol% n-butane; or both. In certain embodiments, the evaporative emission control canister system further includes at least one vent-side subsequent adsorbent volume, wherein the at least one vent-side subsequent adsorbent volume has: a nominal BWC of less than 8 g / dL; a nominal IAC at 25° C. of less than 35 g / L at a vapor concentration of between 5 vol% and 50 vol% n-butane; or both. In certain embodiments, the at least one fuel-side adsorbent volume, the at least one vent-side particulate volume, or both have a ratio of the volume of macropores to the volume of micropores greater than about 200%, wherein the at least one vent-side particulate adsorbent volume has a butane retention rate of less than 1.0 g / dL.

[0044] In any aspect or embodiment described herein, the system further comprises at least one of the following: a fuel vapor inlet conduit that connects an evaporative emission control canister system to a fuel tank; a fuel vapor purge conduit that connects the evaporative emission control canister system to an air intake system of an engine; a vent conduit for venting the evaporative emission control canister system and for introducing purge air into the evaporative emission control canister system; or a combination thereof.

[0045] In some embodiments, the system has at least one of the following: a fuel vapor flow path from the fuel vapor inlet conduit through each of the plurality of adsorbent volumes (i.e., at least one fuel side adsorbent volume upstream of at least one vent side particulate adsorbent volume and optionally at least one subsequent adsorbent volume) to the vent conduit; an air flow path from the vent conduit through each of the plurality of adsorbent volumes (optionally at least one subsequent adsorbent volume, the at least one vent side specific adsorbent volume, and the at least one fuel side adsorbent volume) to a fuel vapor purge outlet; or both.

[0046] In yet another embodiment, the packed bed of the at least one vent side particulate adsorbent volume has a pressure drop of ≤ 40 Pa / cm at an apparent linear air velocity of 46 cm / s.

[0047] In another aspect, the present disclosure provides an evaporative emission control system comprising: a fuel tank for storing fuel; an engine having an air intake system and adapted to consume fuel; an evaporative emission control canister system; a fuel vapor purge conduit that connects the evaporative emission control canister system to the air intake system of the engine; and a vent conduit for venting the evaporative emission control canister system and for introducing purge air into the evaporative emission control canister system, wherein the evaporative emission control canister system is defined by: a fuel vapor inlet conduit that connects the evaporative emission control canister system to the fuel tank; a fuel vapor flow path from the fuel vapor inlet conduit through a plurality of adsorbent volumes to the vent conduit; and an air flow path from the vent conduit through the plurality of adsorbent volumes and a fuel vapor purge outlet.

[0048] In certain embodiments, the evaporative emissions control system includes one or more canisters, the one or more canisters including a plurality of adsorbent volumes, the plurality of adsorbent volumes including at least one vent side particulate adsorbent volume, the at least one vent side particulate adsorbent volume including a particulate adsorbent volume having, for example, a low retention particulate adsorbent with at least one of the following: (i) micropores having a diameter of less than about 100 nm, macropores having a diameter of about 100 to 100,000 nm, and a ratio (M / m) of the volume of macropores to the volume of micropores greater than about 150%; (ii) a retention rate from about 1 to 0.25 g / dL or less; (iii) a particulate diameter starting from about 210 mm; or (iv) a combination thereof. In certain embodiments, the particulate diameter is from about 3 to 10 mm, from about 3 to 9 mm, from about 3 to 8 mm, from about 3 to 7 mm, from about 3 to 6 mm, from about 3 to 5 mm, from about 2 to 9 mm, from about 2 to 8 mm, from about 2 to 7 mm, or from about 2 to 6 mm.

[0049] In certain embodiments, the at least one vent side particulate adsorbent volume has a length / diameter (L / D) ratio of at least 0.5, 1, 1.5, 2, or greater.

[0050] In other embodiments, the evaporative emissions control system includes a plurality of canisters connected to allow sequential contact by fuel vapor.

[0051] In a further aspect, the present disclosure provides a method for reducing fuel vapor emissions in an evaporative emissions control system, the method including contacting fuel vapor with at least one vent side particulate adsorbent, the at least one vent side particulate adsorbent including at least one of the following: micropores having a diameter of less than about 100 nm; macropores having a diameter of about 100 to 100,000 nm; and a ratio (M / m) of the volume of macropores to the volume of micropores greater than about 150%, a retention rate from about 1 to 0.25 g / dL or less, a particulate diameter from about 3 to 6 mm; or a combination thereof.

[0052] In some embodiments, the method further includes contacting the fuel vapor with at least one fuel side adsorbent volume described herein before the fuel vapor contacts the at least one vent side particulate adsorbent described herein.

[0053] In any aspect or embodiment described herein, the adsorbent is located within a single canister. In certain embodiments, the adsorbent is located within a plurality of canisters connected to allow sequential contact by fuel vapor.

[0054] The foregoing general utility fields are given by way of example only and are not intended to limit the scope of the present disclosure and the appended claims. Based on the present claims, specification, and examples, those of ordinary skill in the art will appreciate additional objects and advantages related to the compositions, methods, and processes of the present disclosure. For example, various aspects and embodiments of the present disclosure can be utilized in numerous combinations, all of which are explicitly contemplated by the present disclosure. These additional advantageous objects and embodiments are explicitly included within the scope of the present disclosure. Publications and other materials used herein to clarify the background of the invention and to provide additional details regarding practice in specific instances are incorporated by reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0055] The drawings incorporated in and forming a part of this specification illustrate several embodiments of the invention and, together with the specification, are used to explain the principles of the invention. The drawings are provided only for the purpose of illustrating embodiments of the invention and should not be construed as limiting the invention. Additional objects, features, and advantages of the invention will become apparent from the following detailed description in conjunction with the drawings, which illustrate exemplary embodiments of the invention, wherein:

[0056] Figure 1 Shows a cross-sectional view of an evaporative emission control canister system according to the present disclosure.

[0057] Figure 2 Shows a cross-sectional view of an evaporative emission control canister system according to the present disclosure.

[0058] Figure 3A 、 Figure 3B 、 Figure 3C 、 Figure 3D 、 Figure 3E 、 Figure 3F 、 Figure 3G 、 Figure 3H1 、 Figure 3H2 and Figure 3I Show examples of alternative adsorbent morphologies of low retention particulate adsorbents.

[0059] Figure 4 Is a cross-sectional view of an apparatus for measuring the pressure drop generated by a particulate adsorbent.

[0060] Figure 5 、 Figure 6 、 Figure 7 、 Figure 8 、 Figure 9 、 Figure 10 、 Figure 11 and Figure 12 Help to illustrate how to calculate the nominal volume apparent density.

[0061] Figure 13 Is a simplified schematic view of an apparatus for determining butane adsorption capacity.

[0062] Figure 14 Table 1 is shown. Main tank configuration, including in certain embodiments, a main tank including a plurality of chambers and / or a plurality of adsorbent volumes.

[0063] Figure 15 Tables 2-A, 2-B, and 2-C are shown. Supplemental tank configuration.

[0064] Figure 16 Tables 3-A, 3-B, and 3-C are shown, where subsequent adsorbent volume information for the vent side of Examples 29 to 33, 73, 74, 94, 96, and 106 to 111 is provided.

[0065] Figure 17 Is a graph of the day 2 emissions relative to the system purge BV for Examples 29 to 31.

[0066] Figure 18 Is a graph of the incremental adsorbent adsorption capacity versus the vapor path length.

[0067] Figure 19 Is a graph of the adsorbent butane working capacity versus the vapor path length.

[0068] Figure 20 Is a graph of the adsorbent g-total butane working capacity versus the vapor path length.

[0069] Figure 21 Shows the well-known performance trade-off of using conventional solid particle adsorbents (cylindrical pellets) with diameters of 2 to 5 mm in terms of providing reasonable flow restriction and target flexibility in DBL emission performance. These examples are applicable to a main tank having one or more vent side adsorbent volumes (with alternative adsorbent fills) as described in Tables 2 and 3.

[0070] Figure 22 Shows the effect of the length / diameter ratio on the two-day DBL of an evaporative emission control system having a tank with one or more vent side adsorbent volumes (with alternative adsorbent fills) as described in Tables 2 and 3.

[0071] Figure 23 Shows the effect of the length / diameter ratio on the pressure drop of an evaporative emission control system having a tank with one or more vent side adsorbent volumes (with alternative adsorbent fills) as described in Tables 2 and 3. Note that the particle adsorbents described herein provide a reduced bed pressure drop compared to currently available particle adsorbents.

[0072] Figure 24Shows the flow restrictions of a conventional particulate adsorbent and a carbon honeycomb for typical flow rates (slpm or lpm).

[0073] Figure 25 Shows Figures 21 to 23 Typical flow rates in terms of gas velocity in the plenum side volume in

[0074] Figure 26 Shows the invention embodiments of particulate adsorbents that can provide low DBL emissions and low flow restriction performance compared to the conventional materials exemplified in Figure 21

[0075] Figure 27 Shows a high-performance exemplary or inventive plenum side particulate adsorbent volume of a carbon honeycomb with a high chamber L / D greater than 2.

[0076] Figure 28 Shows the flow restrictions of an exemplary or inventive particulate adsorbent and a carbon honeycomb for typical flow rates (slpm).

[0077] Figure 29 Shows the effect of the length / diameter ratio of a carbon honeycomb on the pressure drop of an evaporative emission control system having one or more exemplary or inventive plenum side particulate adsorbent volumes.

[0078] Figure 30 Shows the flow rate expressed in terms of gas velocity of an emission canister system including an exemplary or inventive plenum side particulate adsorbent volume compared to a carbon honeycomb.

[0079] Figure 31 Shows examples from Figure 26 where after a butane loading step of 40 g / h, a purge of < 100 BV and < 210 liters level is applied.

[0080] Figure 32 Shows that when a second chamber is added, the system emissions show low flow restriction and low emissions, where the second chamber includes an invention embodiment ("adsorbent 2") in the bed.

[0081] Figure 33 Shows the two-day DBL emissions of the plenum side particulate adsorbent volume contained in the adsorbent 2 chamber under low purge conditions (i.e., < 100 BV) as described herein, where the adsorbent 2 chamber has an L / D ratio similar to that of a carbon honeycomb (transferring to a lower L / D value).

[0082] Figure 34 Shows the Figure 32 and Figure 33 bed pressure drop of an exemplary or inventive plenum side particulate adsorbent volume contained in the adsorbent 2 chamber, where the adsorbent 2 volume has an L / D ratio similar to that of a carbon honeycomb.​

[0083] Figure 35 Shows the two-day DBL emissions of the particles of the present invention having an M / m ratio of ≥150% under 315 L (139 BV) purge conditions.

[0084] Figure 36 Shows the two-day DBL emissions of the particles of the present invention having a retention rate of less than about 0.5 g / dL under 315 L (139 BV) purge conditions.

[0085] Figure 37 Shows the two-day DBL emissions of the particles of the present invention having an M / m ratio of ≥150% under 315 L (137 to 147 BV) purge conditions.

[0086] Figure 38 Shows the two-day DBL emissions of the particles of the present invention having a retention rate of less than about 0.5 g / dL under 315 L (137 to 147 BV) purge conditions.

[0087] Figure 39 Shows the low-flow restriction properties of exemplary vent-side low-flow restriction particles in an emission canister system of a control carbon honeycomb and conventional particles.

[0088] Figure 40 Shows the low-flow restriction properties of exemplary vent-side low-flow restriction particles in an emission canister system of a control carbon honeycomb and conventional particles.

[0089] Figure 41 Shows the high-performance exemplary vent-side particle adsorbent volume with a high chamber L / D greater than 2 of a control carbon honeycomb and conventional particles.

[0090] Figure 42 Shows Figure 26 and Figure 27 The pellet strength of the particle adsorbent as a function of the M / m property in the examples of, where "LFR" represents low flow restriction.

[0091] Figure 43 Shows Figure 26 and Figure 27 Examples of a low-flow restriction particle adsorbent that can achieve excellent control of DBL emissions while exhibiting good pellet strength and having (or despite having) a high M / m property.

[0092] Figure 44 Shows Figure 35 and Figure 36 The pellet strength of the exemplary low-flow restriction particle adsorbent in the examples of. Detailed Description

[0093] The present disclosure will now be described more fully hereinafter, but not all embodiments of the disclosure are shown. Although the present disclosure has been described in conjunction with exemplary embodiments, those skilled in the art will understand that various changes can be made and elements thereof can be replaced with equivalents without departing from the scope of the present disclosure. Additionally, many modifications can be made to adapt a particular structure or material to the teachings of the present disclosure without departing from the essential scope thereof.

[0094] The accompanying drawings of this application are for illustrative purposes only. They are not intended to limit the embodiments of the present disclosure. Additionally, these drawings are not drawn to scale. Elements common to the figures may retain the same numerical reference.

[0095] Where a range of values is provided, it is to be understood that each intermediate value between the upper and lower limits of that range, as well as any other stated or intermediate value in that range, is included in the present invention. The upper and lower limits of these smaller ranges may independently be included in a smaller range and are also covered by the present invention, subject to any specific exclusion limits within the stated range. When the stated range includes one or both of the limitations, ranges excluding either of those limitations are also included in the present disclosure.

[0096] The following terms are used to describe the present invention. Where a term is not specifically defined herein, that term is given the meaning generally recognized in the art as applied by one of ordinary skill in the art in the context of its use to describe the present invention.

[0097] As used herein and in the appended claims, the articles "a" and "an" are used herein to refer to one or more than one (i.e., at least one) grammatical object of the article, unless the context clearly dictates otherwise. For example, "an element" means one element or more than one element.

[0098] As used herein in the specification and claims, the phrase "and / or" should be understood to mean "either or both" of the elements so combined, i.e., elements that are present conjunctively in some cases and disjunctively in other cases. Multiple elements listed with "and / or" should be construed in the same manner, i.e., "one or more" of the elements so combined. Other elements may optionally be present in addition to those specifically identified by the "and / or" clause, whether related or unrelated to those specifically identified. Thus, as a non-limiting example, when used in conjunction with open-ended language such as "comprising," a reference to "A and / or B" can in one embodiment refer only to A (optionally including elements other than B); in another embodiment only to B (optionally including elements other than A); in yet another embodiment to both A and B (optionally including other elements); and so on.

[0099] As used herein in the specification and claims, "or" should be understood to have the same meaning as "and / or" as defined above. For example, when separating items in a list, "or" or "and / or" should be interpreted inclusively, i.e., including at least one, but also including more than one of a number of elements or list of elements, and optionally, additional unlisted items. Only terms that specifically state the contrary, such as "only one" or "exactly one," or, when used in the claims, "consisting of" refer to exactly one of a number of elements or list of elements. In general, when preceded by exclusive terms such as "either," "one of," "only one," or "exactly one," the term "or" as used herein should be interpreted only as indicating exclusive alternatives (i.e., "one or the other but not both").

[0100] In the claims, as well as in the specification above, all transitional phrases, such as "comprising," "including," "carrying," "having," "containing," "involving," "holding," "consisting of," and the like, should be understood to be open-ended, i.e., to mean including but not limited to. Only the transitional phrases "consisting of" and "consisting essentially of" should be closed or semi-closed transitional phrases, respectively, as set forth in Section 2111.03 of the Manual of Patent Examining Procedures of the United States Patent Office.

[0101] As used herein in the specification and claims, when referring to a list of one or more elements, the phrase "at least one" should be understood to mean at least one element selected from any one or more of the elements in the list of elements, but not necessarily including at least one of each and every element specifically listed in the list of elements, and not excluding any combinations of elements in the list of elements. This definition also allows that, optionally, elements may exist whether related or unrelated to the specifically identified elements in addition to the elements specifically identified within the list of elements to which the phrase "at least one" refers. Thus, as a non-limiting example, "at least one of A and B" (or equivalently, "at least one of A or B", or equivalently "at least one of A and / or B") in one embodiment may refer to at least one, optionally including more than one A, without B (and optionally including elements other than B); in another embodiment, it may refer to at least one, optionally including more than one B, without A (and optionally including elements other than A); in yet another embodiment, it may refer to at least one, optionally including more than one A, and at least one, optionally including more than one B (and optionally including other elements); and so on. It should also be understood that, unless clearly indicated to the contrary, in any method claimed herein that includes more than one step or act, the order of the steps or acts of the method is not necessarily limited to the order in which the steps or acts of the method are recited.

[0102] As used herein, the terms "gaseous" and "vaporous" are used in a general sense and are interchangeable unless the context indicates otherwise.

[0103] As used herein, the term "adsorbent component" or "adsorbent volume" refers to the adsorbent material or the material containing the adsorbent along the vapor flow path and may consist of a bed of particulate material, monolith, honeycomb, sheet, or other material.

[0104] As used herein, the term "upstream" refers to a location / volume within the system that is before or prior to another location / volume within the system and that is in contact with a fluid such as fuel vapor. That is, the upstream location / volume is positioned relative to the location / volume towards the fuel vapor inlet.

[0105] As used herein, the term "downstream" refers to a location / volume within the system that is after or subsequent to another location / volume within the system and that is in contact with a fluid such as fuel vapor. That is, the downstream location / volume is positioned relative to the location / volume at the distal end of the fuel vapor.

[0106] This specification provides an evaporative emission control canister system that includes one or more canisters, the one or more canisters including at least one particulate adsorbent volume as described herein. The canister may also include other adsorbent volumes as described herein, e.g., at least one fuel-side adsorbent volume, and / or at least one vent-side post-adsorbent volume. In a preferred embodiment, the at least one particulate adsorbent volume is located downstream of the fluid path from the fuel-side adsorbent volume (i.e., vent-side particulate adsorbent volume). In additional embodiments, the vent-side particulate adsorbent volume is a low-retention vent-side particulate adsorbent volume. As used herein, unless the context otherwise indicates, "low retention" or "low butane retention" refers to a butane retention of less than about 2 g / dL, preferably less than about 1 g / dL.

[0107] Evaporative emission canister system

[0108] Figure 1 Non-limiting examples of some embodiments of an evaporative emission control canister system as described herein are shown, the evaporative emission control canister system including a single canister having at least one adsorbent volume (such as a fuel-side adsorbent volume) and at least one vent-side adsorbent volume (i.e., downstream of the initial adsorbent). Canister system 100 includes a support screen 102, a partition wall 103, a fuel vapor inlet 104 from a fuel tank, a vent 105 to the atmosphere, a purge outlet 106 to an engine, a fuel-side adsorbent volume 201, and at least one vent-side adsorbent volume 202, 203, 204. However, it should be noted that any particular adsorbent volume may include one or more of 201, 202, 203, and 204. That is, the fuel-side adsorbent volume may include 201 and 202, and / or the vent-side adsorbent volume may include 203 and 204. The adsorbent volumes are connected (in fluid communication) to allow directed and sequential contact by a fluid (e.g., air, gas, or fuel vapor).

[0109] When the engine is off, fuel vapor from the fuel tank enters canister system 100 through fuel vapor inlet 104. In this example, the fuel vapor diffuses into the initial fuel-side adsorbent volume 201, then into the at least one vent-side (i.e., downstream) adsorbent volume, and then is released to the atmosphere through vent 105 of the canister system. Once the engine is started, ambient air is drawn into canister system 100 through vent 105. The purge air flows through the at least one vent-side (i.e., downstream) adsorbent volume 204, 203, 202, then through the fuel-side adsorbent volume 201, and desorbs the fuel vapor adsorbed on the adsorbent volumes 204, 203, 202, 201, and then enters the internal combustion engine through purge outlet 106.

[0110] An evaporative emission control canister system may include a void volume within the canister. As used herein, the term "void volume" refers to a volume that does not include any adsorbent. Such a volume may include any non-adsorbent, including but not limited to an air gap, a foam spacer, a screen, or a combination thereof. The void volume may be located Figure 1 in any of the depicted volumes 201, 202, 203, 204 shown, or may be found between, before, or after any of the depicted volumes 201, 202, 203, 204.

[0111] Figure 2 Non-limiting examples of other embodiments of an evaporative emission control canister system are shown that include more than one canister having a plurality of adsorbent volumes. For example, a fuel-side adsorbent volume and at least one vent-side adsorbent volume are located in separate canisters, where the adsorbent volumes are connected (in fluid communication) to allow for directed and sequential contact of fuel vapors from one volume (and canister) to the next. As Figure 2 shown, the canister system 100 includes a main canister 101, a support screen 102, a partition wall 103, a fuel vapor inlet 104 from a fuel tank, a vent 105 to the atmosphere, a purge outlet 106 to an engine, an initial fuel-side adsorbent volume 201 in the main canister 101, vent-side adsorbent volumes 202, 203, 204 downstream of the initial fuel-side adsorbent volume 201 in the main canister 101, a supplemental canister 300 including at least one additional vent-side adsorbent volume 301, 302, 303, 304, 305, and a conduit 107 connecting the main canister 101 to the supplemental canister 300. Similar to the main canister, the additional vent-side adsorbent volumes in the supplemental canister may include a single adsorbent located at a plurality of the depicted adsorbent volumes 301, 302, 303, 304, 305.

[0112] In addition, the supplemental canister of the evaporative emission control canister system may include a void volume, which may be found Figure 2 in any of the depicted volumes 301, 302, 303, 304, 305 shown, or may be found between, before, or after any of the depicted volumes 301, 302, 303, 304, 305. For example, at least one or both of 302, 304 are void volumes. As previously described, the term "void volume" refers to a volume that does not include any adsorbent. Such a volume may include any non-adsorbent, including but not limited to an air gap, a foam spacer, a screen, a conduit, or a combination thereof.

[0113] When the engine is turned off, fuel vapor from the fuel tank enters the canister system 100 through the fuel vapor inlet 104 leading to the main canister 101. The fuel vapor diffuses through the initial fuel-side adsorbent volume 201, then through the vent-side adsorbent volumes (202, 203, and 204) in the main canister 101, and then enters the secondary canister 300 via the conduit 107. The fuel vapor diffuses through one or more vent-side adsorbent volumes 301, 302, 303, 304, 305 inside the secondary canister 300 and is then released to the atmosphere through the vent 105 of the canister system. Once the engine is started, ambient air is drawn into the canister system 100 through the vent 105. The purge air flows through one or more vent-side adsorbent volumes 305, 304, 303, 302, 301 in the secondary canister 300, the vent-side adsorbent volumes (204, 203, 202) in the main canister 101, and then flows through the fuel-side adsorbent volume 201 in the main canister 101 to desorb the fuel vapor adsorbed on the adsorbent volumes (305, 304, 303, 302, 301, 204, 203, 202, 201), and then enters the internal combustion engine through the purge outlet 106.

[0114] In addition, the evaporative emission control canister system may include a void volume between the main canister and the secondary canister.

[0115] When needed, as described herein, the evaporative emission control canister system may include more than one secondary canister. The evaporative emission control canister system may also include one or more void volumes between the main canister and the first secondary canister, between the secondary canisters, and / or at the end of the last secondary canister. As a non-limiting example, the evaporative emission control canister system may include a main canister, a first secondary canister, a second secondary canister, a third secondary canister, a void volume between the main canister and the first secondary canister, a void volume between the first secondary canister and the second secondary canister, and a void volume at the end of the third secondary canister. Each secondary canister may also include one or more additional adsorbent volumes.

[0116] When needed, the total adsorbent volume (i.e., the sum of the adsorbent volumes) may be the same as the volume of the evaporative emission control canister system. Alternatively, the total adsorbent volume may be less than the volume of the evaporative emission control canister system.

[0117] Accordingly, in one aspect, the present disclosure provides an evaporative emission control canister system comprising: one or more canisters having a plurality of chambers, each chamber defining a volume, the plurality of chambers being connected or in fluid communication to allow fluid (e.g., air, gas, or fuel vapor) to flow directionally and sequentially from one chamber to the next, wherein at least one chamber comprises at least one particulate adsorbent volume, the at least one particulate adsorbent volume comprising a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 nm to 100,000 nm, and a ratio of the volume of macropores to the volume of micropores greater than about 150%, and wherein the at least one particulate adsorbent volume has at least one of the following: (i) a flow limiting property of less than 40 Pa / cm pressure drop under conditions of applying an apparent linear air velocity of 46 cm / s to a 43 mm diameter bed of particulate adsorbent material; (ii) a flow limitation of less than 0.3 kPa at an air flow rate of 40 lpm; (iii) a butane retention rate of less than about 0.5 g / dL; (iv) a length to diameter ratio greater than about 2; or (v) a combination thereof.

[0118] In certain embodiments, the canister system comprises at least one additional adsorbent volume. In certain embodiments, the adsorbent volume is located within a single canister or within multiple canisters that are connected to allow sequential contact by fuel vapor.

[0119] In certain embodiments, the canister system further comprises at least one fuel side adsorbent volume, wherein the at least one fuel side adsorbent volume has: a nominal BWC of > 8 g / dL; a nominal IAC at 25°C of > 35 g / L between a vapor concentration of 5 vol% and 50 vol% n-butane; or both.

[0120] In certain embodiments, the canister system further comprises at least one vent side post adsorbent volume, wherein the at least one vent side post adsorbent volume has: a nominal BWC of less than 8 g / dL; a nominal IAC at 25°C of less than 35 g / L between a vapor concentration of 5 vol% and 50 vol% n-butane; or both. In certain embodiments, the at least one particulate adsorbent volume, the at least one vent side post adsorbent volume, or both have: a BWC of less than 8 g / dL; an IAC at 25°C of less than 35 g / L between a vapor concentration of 5 vol% and 50 vol% n-butane.

[0121] In some embodiments, the evaporative emissions control canister system includes at least one fuel - side adsorbent volume having: a nominal butane working capacity (BWC) of at least 8 g / dL (e.g., at least 10 g / L); a nominal incremental adsorption capacity (IAC) at 25 °C of at least 35 g / L between vapor concentrations of 5 vol% and 50 vol% n - butane; or both.

[0122] In some embodiments, the adsorbent volume is located in a single canister or in multiple canisters that are connected to allow sequential contact by fuel vapor.

[0123] In some embodiments, the particulate adsorbent volume has an M / m ratio greater than about 200%. In some embodiments, the particulate adsorbent volume has a butane retention rate of less than about 2.0 g / dL or less than 1.0 g / dL or less than 0.5 g / dL.

[0124] In some embodiments, the at least one particulate adsorbent is located on the vent side of the canister system, on the fuel side of the canister system, or both.

[0125] In some embodiments, the evaporative emissions control canister system includes at least one fuel - side adsorbent volume, at least one vent - side post - adsorbent volume, or both.

[0126] In some embodiments, the adsorbent volume is located in a single canister or in multiple canisters that are connected to allow sequential contact by fuel vapor. In some embodiments, the at least one particulate adsorbent volume, the at least one fuel - side adsorbent volume, or both have: a BWC of at least 8 g / dL (e.g., at least 10 g / L); an IAC at 25 °C of at least 35 g / L between vapor concentrations of 5 vol% and 50 vol% n - butane; or both. In some embodiments, the at least one particulate adsorbent volume, the at least one vent - side post - adsorbent volume, or both have: a BWC of less than 8 g / dL; an IAC at 25 °C of less than 35 g / L between vapor concentrations of 5 vol% and 50 vol% n - butane; or both. In some embodiments, the particulate volume has a ratio of the volume of macropores to the volume of micropores greater than about 200%.

[0127] In another aspect, the present specification provides an evaporative emission control canister system that includes one or more canisters, the one or more canisters including at least one fuel-side adsorbent volume (i.e., an adsorbent volume at or near the fuel tank vapor inlet 104) and at least one vent-side particulate adsorbent volume such as a vent-side low-retention particulate adsorbent volume. The term "vent-side" refers to a location downstream of or closer to the vent relative to the at least one fuel-side adsorbent volume. Thus, when the vehicle is stationary, the at least one fuel-side adsorbent volume contacts fuel vapor from the gas tank before any other adsorbent volume (i.e., downstream-directed from 104 to 105) in the fluid path (from the fuel tank to the vent) that is downstream of the fuel-side adsorbent volume.

[0128] In some embodiments, the system includes a plurality of vent-side particulate adsorbent volumes such as vent-side low-retention particulate adsorbent volumes, the plurality of vent-side particulate adsorbent volumes being configured to allow sequential contact by a fluid such as fuel vapor. In certain embodiments, for example, the adsorbents are connected in series, thereby defining a fluid flow path therethrough. In certain embodiments, the system includes a plurality of canisters, the plurality of canisters being connected to allow sequential contact by a fluid such as fuel vapor.

[0129] Reference Figure 1 and Figure 2 , the adsorbent can be located within a single canister or within a plurality of canisters, the plurality of canisters being connected to allow sequential contact by a fluid such as fuel vapor (e.g., 2, 3, 4, 5, 6, 7, or 8 canisters). In a particular embodiment, the adsorbent is located within a plurality of canisters, the plurality of canisters being connected to allow sequential contact by fuel vapor. For example, in certain embodiments, for example with reference to Figure 1 and Figure 2 , the vent-side particulate adsorbent volume such as the vent-side low-retention particulate adsorbent volume is located in at least one volume of the main canisters 202, 203, or 201; and / or in at least one of the supplementary canisters such as 301, 302, 303, 304, or 305. Thus, in certain embodiments, the low-retention particulate adsorbent can be found in at least one of the volumes 201, 202, 203, and 204 of the main canisters; in at least one of the volumes 301, 302, 303, 304, 305 of the supplementary canisters, or a combination thereof.

[0130] The present disclosure also contemplates including additional adsorbent volume in any number of combinations readily understandable from the present disclosure. For example, after or downstream of the subsequent adsorbent volume on the ventilation side, additional ventilation side or low retention particulate adsorbents as described herein may be present. If a refill canister is present, the refill canister may include a ventilation side adsorbent volume or a low retention adsorbent volume on the ventilation side (e.g., volume 305) and on the main canister side (e.g., volume 301), with a downstream ventilation side subsequent adsorbent volume (e.g., volumes 302, 303, 304) therebetween. Similarly, a ventilation side or low retention adsorbent may be present on the main canister side of the refill canister (e.g., volume 301) and on the refill canister side of the main canister (e.g., volume 204), where the canister system includes a high butane working capacity upstream of the ventilation side or low retention adsorbent. The system may also be configured to include a ventilation side subsequent adsorbent volume (e.g., volume 304) downstream of the ventilation side or low retention adsorbent volume (e.g., volume 301), and the system may optionally include yet another low retention adsorbent volume after the subsequent adsorbent volume (e.g., volume 305).

[0131] In any aspect or embodiment described herein, the ventilation-side particulate adsorbent has micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, and a ratio (M / m) of the volume of macropores to the volume of micropores that is greater than about 150%, 160%, 170%, 180%, 190%, 200%, 210%, 220%, 250%, 275%, 280%, 300% or greater. In certain embodiments, the ventilation-side particulate adsorbent has an M / m ratio ranging from 150% to about 170%, from about 160% to about 180%, from about 170% to about 190%, from about 180% to about 200%, from 190% to about 210%, from 200% to about 220% or greater than 220%. In other embodiments, the volume ratio is greater than about 150% to about 1000%, greater than about 150% to about 800%, greater than about 150% to about 600%, greater than about 150% to about 500%, greater than about 150% to about 400%, greater than about 150% to about 300%, greater than about 150% to about 200%, about 175% to about 1000%, about 175% to about 800%, about 175% to about 600%, about 175% to about 500%, about 175% to about 400%, about 175% to about 300%, about 175% to about 200%, about 200% to about 800%, about 200% to about 600%, about 200% to about 500%, about 200% to about 400%, about 200% to about 300%, about 300% to about 800%, about 300% to about 600%, about 300% to about 500%, about 300% to about 400%, about 400% to about 800%, about 400% to about 600%, about 400% to about 500%, about 500% to about 800%, about 500% to about 600%, or about 600% to about 800%.

[0132] In any aspect or embodiment described herein, the ventilation-side particulate adsorbent volume, such as the ventilation-side low-retention particulate adsorbent volume, has a flow restriction of less than about 0.3 kPa at an air flow rate of 40 lpm; a flow restriction property of less than 40 Pa / cm pressure drop at an apparent linear air velocity of 46 cm / s; or both.

[0133] In any aspect or embodiment described herein, the vent-side particulate adsorbent volume, such as the vent-side low-retention particulate adsorbent volume, has a length-to-diameter ratio (L / D) of about 0.5, 1, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5 or greater, including all values therebetween. In certain embodiments, the vent-side particulate adsorbent volume is elongated and has an L / D ratio greater than about 2. In certain embodiments, the L / D ratio ranges from about 1.0 to about 6.0, from about 1.25 to about 5.75, from about 1.5 to about 5.5, from about 1.75 to about 5.0, or from about 2 to about 4.75.

[0134] In any aspect or embodiment described herein, the at least one vent-side particulate adsorbent volume, such as the vent-side low-retention particulate adsorbent volume, has a butane retention of ≤ about 2 g / dL, ≤ about 1.5 g / dL, ≤ about 1 g / dL, ≤ about 0.9 g / dL, ≤ about 0.8 g / dL, ≤ about 0.7 g / dL, ≤ about 0.6 g / dL, ≤ about 0.5 g / dL, ≤ about 0.4 g / dL, ≤ about 0.3 g / dL, ≤ about 0.2 g / dL, or ≤ about 0.1 g / dL. In certain embodiments, the at least one vent-side particulate adsorbent volume, such as the vent-side low-retention particulate adsorbent volume, has a butane retention ranging from about 0.01 g / dL to about 2.5 g / dL, from about 0.01 g / dL to about 2.0 g / dL, from about 0.01 g / dL to about 1.5 g / dL, from about 0.01 g / dL to about 1.0 g / dL, from about 0.01 g / dL to about 0.75 g / dL, from about 0.25 g / dL to about 1.00 g / dL, from about 0.25 g / dL to about 0.75 g / dL, from about 0.25 g / dL to about 0.50 g / dL, from about 0.50 g / dL to about 1.00 g / dL, from about 0.50 g / dL to about 0.75 g / dL, or from about 0.75 g / dL to about 1.00 g / dL.

[0135] One advantageous feature of the particulate adsorbents described herein, such as the low-retention adsorbents described herein, is that they have flow restriction properties that are low enough such that they can be used as an alternative to, for example, foams, polymers, or paper sheets or honeycomb monolithic adsorbents. For example, Figure 21 illustrates how the flow restriction of prior art particulate adsorbents with diameters of 2 to 3 mm is many times that of commercially available carbon honeycombs used as emission "scrubbers" on the vent side of canister systems. Thus, in any aspect or embodiment, the vent-side particulate adsorbent, such as the vent-side low-retention adsorbent, has a particle diameter ranging from about 3 to 10 mm, from about 3 to 9 mm, from about 3 to 8 mm, from about 3 to 7 mm, from about 3 to 6 mm, from about 3 to 5 mm, or from about 3 to 4 mm.

[0136] In certain embodiments, the main tank includes a high butane working capacity adsorbent, the vent side of the main tank and / or the main tank side of the refill tank includes a low retention particulate adsorbent as described herein, and the vent portion of the refill tank includes a subsequent adsorbent volume on the vent side. In certain embodiments, the subsequent adsorbent volume on the vent side is a material with low flow restriction, such as foam, polymer, or paper sheet, or honeycomb such as activated carbon honeycomb.

[0137] In certain embodiments, the at least one fuel side adsorbent volume has at least one of the following: a high butane working capacity (BWC) relative to the vent side adsorbent volume; an effective incremental adsorption capacity greater than about 35 grams of n-butane per liter (g / L) at a vapor concentration between 5 vol% and 50 vol% n-butane; or both.

[0138] In any aspect or embodiment described herein, the fuel side adsorbent volume of the tank system has at least one of the following: i) a nominal butane working capacity (BWC) greater than 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25 g / dL or more grams per deciliter (g / dL); ii) an incremental adsorption capacity greater than 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54, 55, 60, 65, 70, 75, 80, 85, 90 or more grams of n-butane per liter (g / L) at a vapor concentration between 5 vol% and 50 vol% n-butane; or both.

[0139] In certain embodiments, the high butane working capacity adsorbent includes high working capacity activated carbon. These can be obtained commercially under the trade names BAX 1100, BAX 1100LD, BAX 1500 and BAX 1700 ( North Charleston, South Carolina, USA). The high butane working capacity volume can include multiple volumes containing the high butane working capacity adsorbent. For example, the main tank can include two high butane working capacity volumes (e.g., BAX 1100 volume and BAX 1500 volume).

[0140] In any aspect or embodiment described herein, the evaporative emission control canister system further includes at least one vent-side post adsorbent volume, wherein the at least one vent-side post adsorbent volume has: a nominal BWC of less than 8, 7, 6, 5, 4, 3, 2, or 1 g / dL; a nominal IAC at 25 °C of less than 35, 34, 33, 32, 31, 30, 29, 28, 37, 36, 35, 34, 23, 22, 21, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, or 1 g / L between a vapor concentration of 5 vol% and 50 vol% n-butane; or both. In certain embodiments, the at least one vent-side post adsorbent volume has a BWC ranging from about 1 g / dL to about 8 g / dL, from about 1 g / dL to about 7 g / dL, from about 1 g / dL to about 6 g / dL, from about 1 to about 5 g / dL, from about 1 g / dL to about 4 g / dL, or from about 1 g / dL to about 3 g / dL. In certain embodiments, the at least one vent-side post adsorbent volume has an IAC (grams of n-butane per liter) ranging from about 1 g / L to about 35 g / L, from about 2 g / L to about 30 g / L, from about 3 g / L to about 25 g / L, from about 3 g / L to about 20 g / L, from about 3 g / L to about 15 g / L, or from about 3 g / L to about 10 g / L between a vapor concentration of 5 vol% and 50 vol% n-butane.

[0141] In certain embodiments, the at least one vent-side post adsorbent volume has at least one of the following: i) a BWC of less than about 8, 7, 6, 5, 4, 3, 2, or 1 g / dL, ii) an IAC of less than about 35, 30, 25, 20, 15, 10, or 5 g of n-butane / L between a vapor concentration of 5 vol% and 50 vol% n-butane, or iii) a combination thereof. In certain embodiments, the post adsorbent volume is an activated carbon honeycomb.

[0142] In certain embodiments, the post adsorbent volume is located upstream, downstream, or both (i.e., vent-side post adsorbent volume) of the vent-side particulate adsorbent volume described herein in the vapor path.

[0143] In any aspect or embodiment described herein, the vent-side post / downstream adsorbent volume is selected from the group consisting of honeycomb adsorbents (e.g., HCA, HCA-LBE, or SquareHCA obtainable from North Charleston, South Carolina, USA ), monolithic adsorbents, or both.

[0144] The disclosed evaporative emission control system provides low diurnal breathing loss (DBL) emissions even under low purge conditions. In certain embodiments, the evaporative emission performance of the disclosed evaporative emission control system may not exceed 50 mg, or within the regulatory limits defined by the California Bleed Emission Test Procedure (BETP) (not exceeding 20). In any aspect or embodiment described herein, as determined by the California Bleed Emission Test Procedure (BETP), with a purge of no more than about 175, 150, 125, 120, 115, 110, 100 bed volumes or less, or with a purge of less than 315, 300, 275, 250, 225, 200, 175, 150 liters or less, the evaporative emission canister system described herein has a two-day DBL of from about 5 to about 50 mg, from about 6 to about 50 mg, from about 7 to about 50 mg, from about 8 to about 50 mg, from about 9 to about 50 mg, from about 10 to about 50 mg, from about 5 to about 45 mg, from about 5 to about 40 mg, from about 5 to about 35 mg, about 5 to about 30 mg, from about 5 to about 20 mg, from about 5 to about 15 mg, or from about 5 to about 10 mg.

[0145] The evaporative emission control system can provide low diurnal breathing loss (DBL) emissions even when purged at 210 liters or less after a 40 g / h butane loading step. In some embodiments, the evaporative emission control system can be purged at 157.5 liters or less applied after a 40 g / h butane loading step.

[0146] The evaporative emission control system can provide low diurnal breathing loss (DBL) emissions even when purged at 150 BV or less after a 40 g / h butane loading step. The evaporative emission control system can provide low diurnal breathing loss (DBL) emissions even when purged at 100 BV or less after a 40 g / h butane loading step. In some embodiments, the evaporative emission control system can be purged at 75 BV or less applied after a 40 g / h butane loading step.

[0147] In certain embodiments, an evaporative emissions control canister system includes at least one vent-side particulate adsorbent volume, such as a vent-side low-retention particulate adsorbent volume, wherein the at least one vent-side particulate adsorbent has an M / m ratio greater than 150%, and at least one or both of relatively low flow restriction properties and a butane retention rate of < 1.0 g / dL. For example, in certain embodiments, the vent-side particulate adsorbent has an M / m greater than 150% and at least one of the following: a butane retention rate of less than about 0.5 g / dL, a flow restriction of less than 40 Pa / cm pressure drop at an apparent linear gas velocity of 46 cm / s, a flow restriction of less than 0.3 kPa at an air flow rate of 40 lpm, a length-to-diameter ratio (L / D) greater than 2, or combinations thereof. In additional embodiments, the vent-side particulate adsorbent volume has an M / m greater than 200% and at least one of the following: a butane retention rate of less than about 1 g / dL, a flow restriction of less than 40 Pa / cm pressure drop at an apparent linear gas velocity of 46 cm / s, a flow restriction of less than 0.3 kPa at an air flow rate of 40 lpm, a length-to-diameter ratio (L / D) greater than 2, or combinations thereof.

[0148] In certain embodiments, the vent-side particulate adsorbent described herein, such as a vent-side low-retention particulate adsorbent, has an M / m greater than 150% and has flow restriction properties with a pressure drop of less than 40 Pa / cm at an apparent linear air velocity of 46 cm / s. In certain embodiments, the vent-side particulate adsorbent, such as a vent-side low-retention particulate adsorbent, has an M / m greater than 200% and a butane retention rate of less than 1 g / dL. In certain embodiments, the vent-side particulate adsorbent has an M / m greater than 150% and a butane retention rate of less than 0.5 g / dL.

[0149] In certain embodiments, an evaporative emissions control system includes one or more canisters, the one or more canisters including a plurality of adsorbent volumes, the plurality of adsorbent volumes including at least one vent-side particulate adsorbent volume, the at least one vent-side particulate adsorbent volume including, for example, a low-retention particulate adsorbent having at least one of the following: (i) micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, and a ratio of the volume of macropores to the volume of micropores (M / m) greater than about 150%; (ii) a butane retention rate from about 1 g / dL to 0.25 g / dL or less; (iii) a particulate diameter from about 2 to 10 mm; or (iv) combinations thereof.

[0150] In any aspect or embodiment described herein, upon purging not exceeding about 175, 150, 125, 120, 115, 110, 100 bed volumes or less, or upon purging less than 315, 300, 275, 250, 225, 200, 175, 150 liters or less, as determined by the California Bleed Emissions Test Procedure (BETP), the evaporative emissions control canister system has no more than about 50, 45, 40, 35, 30, 25, 20 mg of two-day DBL emissions.

[0151] In certain embodiments, the evaporative emissions control canister system includes at least one vent-side particulate adsorbent having a M / m > 150%, where the vent-side particulate adsorbent volume, e.g., the vent-side low-retention particulate volume, has a flow restriction of less than 40 Pa / cm pressure drop at an apparent linear gas velocity of 46 cm / s, or a flow restriction of less than 0.3 kPa at an air flow rate of 40 lpm, and where the canister system has no more than 50 mg or no more than 20 mg of Day 2 DBL emissions in the BETP test upon purging less than 100 bed volumes or less than 210 liters.

[0152] In a further aspect, the present disclosure provides an evaporative emissions control canister system that includes: one or more canisters, the one or more canisters including at least one vent-side particulate adsorbent volume having a low retention rate, the low-retention particulate adsorbent volume including one or more low-retention particulate adsorbent materials. In certain embodiments, the low-retention particulate adsorbent material has micropores with a diameter of less than about 100 nm; macropores with a diameter of about 100 to 100,000 nm; and a ratio of the volume of macropores to the volume of micropores greater than about 200%, where the particulate adsorbent material has a retention rate of about 1.0 g / dL or less.

[0153] For example, the system can include an upstream adsorbent volume that includes a high butane working capacity adsorbent located upstream or prior to the low-retention adsorbent volume (i.e., the high butane working capacity adsorbent volume contacts a fluid, e.g., fuel vapor, prior to the low-retention adsorbent). The high butane working capacity adsorbent volume can have an adsorbent having at least one of the following: a nominal butane working capacity of at least 8 g / dL (e.g., at least 10 g / dL); a nominal incremental adsorption capacity of at least 35 g / L (e.g., at least 45 g / L); or a combination thereof.

[0154] The system of the present disclosure may include a downstream or subsequent adsorbent volume located downstream of a low retention adsorbent volume (i.e., the upstream adsorbent volume contacts fuel vapor after the low retention adsorbent volume). The downstream adsorbent volume may include an adsorbent having: micropores with a diameter of less than about 100 nm; macropores with a diameter of about 100 to 100,000 nm; and a ratio of the volume of macropores to the volume of micropores that is less than or equal to about 150%. For example, the downstream or subsequent adsorbent may have a ratio of the volume of macropores to the volume of micropores that is equal to or less than about 150%, equal to or less than about 145%, equal to or less than about 140%, equal to or less than about 135%, or equal to or less than about 130%.

[0155] In certain embodiments, the at least one vent side particulate adsorbent volume, such as a vent side low retention particulate adsorbent volume, is included as an alternative to or in combination with one or more vent side subsequent adsorbent volumes. The at least one fuel side adsorbent volume, the at least one vent side particulate adsorbent volume, and / or the at least one vent side subsequent adsorbent volume may be included in a single canister or separate canisters that are connected to allow sequential contact by fuel vapor (and conversely, purge air). In certain embodiments, the at least one vent side subsequent adsorbent volume includes a non-particulate adsorbent material, such as foam, monolith, polymer, or paper sheet or honeycomb (e.g., activated carbon honeycomb), where the at least one vent side subsequent adsorbent volume imposes low vapor or fluid flow restrictions.

[0156] In certain embodiments, an evaporative emission control canister system includes: at least one vent side subsequent adsorbent volume, such as a vent side low retention particulate adsorbent volume, upstream of the at least one vent side particulate adsorbent volume (i.e., located closer to the fuel side adsorbent volume or fuel vapor inlet in the fluid path), at least one vent side subsequent adsorbent volume downstream of the at least one vent side particulate adsorbent volume (i.e., located closer to the vent in the fluid path), or a combination thereof.

[0157] In certain embodiments, an evaporative emission control canister system includes: at least one vent side particulate adsorbent volume, such as a vent side low retention particulate adsorbent volume, upstream of the at least one vent side subsequent adsorbent volume (i.e., located closer to the fuel side adsorbent volume or fuel vapor inlet in the fluid path), at least one vent side particulate adsorbent volume downstream of the at least one vent side subsequent adsorbent volume (i.e., located closer to the vent in the fluid path), or a combination thereof.

[0158] In some embodiments, the evaporative emissions control system may further include one or more heat input units for heating one or more adsorbent volumes and / or one or more void volumes. The heat input unit may include, but is not limited to, an internal resistive element, an external resistive element, or a heat input unit associated with the adsorbent. The heat input unit associated with the adsorbent may be an element separate from the adsorbent (i.e., not in contact with the adsorbent). Alternatively, the heat input unit associated with the adsorbent may be a substrate or layer to which the adsorbent is attached, adhered, non - adhered, or in physical contact. The heat input unit associated with the adsorbent may be an adsorbent directly electrically heated by having an appropriate resistivity. The resistivity characteristics of the adsorbent can be altered by adding conductive or resistive additives and binders during the original preparation of the adsorbent and / or during forming the adsorbent into particulate or monomeric form. The conductive component can be a conductive adsorbent, a conductive substrate, a conductive additive, and / or a conductive binder. The conductive material can be added during adsorbent preparation, during an intermediate forming process, and / or during forming the adsorbent into its final form. Any mode of heat input unit can be used. As a non - limiting example, the heat input unit may include a heat transfer fluid, a heat exchanger, a heat conducting element, and a positive temperature coefficient material. The heat input unit may be uniform or non - uniform (i.e., providing different local intensities) along the length of the heated fluid path. Additionally, the heat input unit may or may not be distributed to have greater intensity and heating duration at different points along the length of the heated fluid path.

[0159] Generally, low - retention particulate adsorbents include adsorbents having: micropores with diameters less than about 100 nm; macropores with diameters from about 100 to 100,000 nm; and a ratio of the volume of macropores to the volume of micropores greater than about 150%, where the particulate adsorbent material has a retention of about 1.0 g / dL or less.

[0160] Any suitable adsorbent material can be used to prepare the adsorbent volume, including but not limited to activated carbon, charcoal, zeolite, clay, porous polymers, porous alumina, porous silica, molecular sieves, kaolin, titanium dioxide, cerium dioxide, or combinations thereof. Activated carbon can be derived from various carbon precursors. As non - limiting examples, the carbon precursors can be wood, wood chips, wood powder, cotton linters, peat, coal, coconut, lignite, carbohydrates, petroleum pitch, petroleum coke, coal tar pitch, fruit pits, fruit stones, nut shells, nut kernels, sawdust, palm, vegetables such as rice husks or straw, synthetic polymers, natural polymers, lignocellulosic materials, or combinations thereof. Additionally, various processes including but not limited to chemical activation, thermal activation, or combinations thereof can be used to produce activated carbon.

[0161] The low-retention particulate adsorbent can be activated carbon (which can be derived from at least one material selected from the group consisting of wood, wood chips, wood powder, cotton linter, peat, coal, coconut, lignite, carbohydrates, petroleum pitch, petroleum coke, coal tar pitch, fruit stones, nut shells, nut kernels, sawdust, palm, vegetables, synthetic polymers, natural polymers, lignocellulosic materials, and combinations thereof), charcoal, molecular sieve, porous polymer, porous alumina, clay, porous silica, kaolin, zeolite, metal-organic framework, titanium dioxide, cerium dioxide, or a combination of at least one of them.

[0162] A variety of adsorbent forms can be used. Non-limiting examples of adsorbent forms can include granular, pellet, spherical, honeycomb, monolithic, pill-shaped cylinder, uniformly shaped particulate media, non-uniformly shaped particulate media, extruded form of structured media, wound form of structured media, folded form of structured media, pleated form of structured media, corrugated form of structured media, cast form of structured media, bonded form of structured media, non-woven fabric, woven fabric, sheet, paper, foam, or a combination thereof. The adsorbent (as a single component or a mixture of different components) can include a volume diluent. Non-limiting examples of volume diluents can include, but are not limited to, spacers, inert voids, foams, fibers, springs, or a combination thereof. Additionally, the adsorbent can be extruded into a special thin-walled cross-sectional shape, such as a hollow cylinder, star, twisted helix, asterisk, configured strip, or other shapes within the technical capabilities of the art. In shaping, inorganic and / or organic binders can be used.

[0163] The honeycomb adsorbent can be of any geometric shape, including but not limited to circular, cylindrical, or square. Additionally, the cell openings of the honeycomb adsorbent can have any geometric shape. A honeycomb with a uniform cross-sectional area for the flow channels (such as a square honeycomb with square cross-sectional cell openings or a corrugated form of spiral wound honeycomb) can perform better than a circular honeycomb with square cross-sectional cell openings in a right-angle matrix, which provides a range of cross-sectional areas for adjacent channels and thus provides channels that are not equally purged. Without being bound by any theory, it is believed that the more uniform the cross-sectional area of the cell openings on the honeycomb surface, the more uniform the flow distribution within the component during both the adsorption and purge cycles, and thus the lower the DBL emissions from the canister system.

[0164] The system of the present disclosure may include at least one of the following: a fuel vapor inlet conduit that connects an evaporative emission control canister system to a fuel tank; a fuel vapor purge conduit that connects the evaporative emission control canister system to an air intake system of an engine; a vent conduit that is used to vent the evaporative emission control canister system and to introduce purge air into the evaporative emission control canister system; or a combination thereof. The system may have at least one of the following: a fuel vapor flow path from the fuel vapor inlet conduit through each of the plurality of adsorbent volumes (i.e., an initial adsorbent volume upstream of at least one subsequent adsorbent volume, where at least one adsorbent volume includes a low retention rate particulate adsorbent) to the vent conduit; an air flow path from the vent conduit through each of the plurality of adsorbent volumes (i.e., subsequent adsorbent volumes, followed by an initial adsorbent upstream of the subsequent adsorbent) to a fuel vapor purge outlet; or both.

[0165] In another aspect, the present disclosure provides an evaporative emission control system including: a fuel tank for storing fuel; an engine having an air intake system and adapted to consume fuel; an evaporative emission control canister system; a fuel vapor purge conduit that connects the evaporative emission control canister system to the air intake system of the engine; and a vent conduit that is used to vent the evaporative emission control canister system and to introduce purge air into the evaporative emission control canister system, wherein the evaporative emission control canister system is defined by: a fuel vapor inlet conduit that connects the evaporative emission control canister system to the fuel tank; a fuel vapor flow path from the fuel vapor inlet conduit through a plurality of adsorbent volumes to the vent conduit; and an air flow path from the vent conduit through the plurality of adsorbent volumes and a fuel vapor purge outlet. The evaporative emission control system includes: one or more canisters, the one or more canisters including a plurality of adsorbent volumes, the plurality of adsorbent volumes including at least one low retention rate adsorbent volume, the at least one low retention rate adsorbent volume including a low retention rate particulate adsorbent, the low retention rate particulate adsorbent having: micropores with a diameter of less than about 100 nm; macropores with a diameter of about 100 to 100,000 nm; a ratio of the volume of macropores to the volume of micropores greater than about 150%; and a retention rate of about 1.0 g / dL or less. The evaporative emission control system includes a plurality of canisters that are connected to allow sequential contact by fuel vapor.

[0166] In some embodiments, the evaporative emission control system may include a heating unit to further improve purge efficiency. As a non-limiting example, the evaporative emission control system may include a heating unit that is used to heat at least one or both of the purge air, the low retention rate adsorbent volume, and / or a subsequent adsorbent volume.

[0167] According to one aspect, the present disclosure provides a method for reducing fuel vapor emissions in an evaporative emission control canister system, the method comprising contacting fuel vapor with a particulate adsorbent volume, such as a vent side low retention particulate adsorbent volume, having micropores with a diameter less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, and a ratio of the volume of macropores to the volume of micropores greater than about 150%, wherein the particulate adsorbent material has a flow restriction property of less than about 40 Pa / cm under conditions of applying an apparent linear air velocity of 46 cm / s to a 43 mm diameter bed of the particulate adsorbent material.

[0168] Fuel side and vent side

[0169] In another aspect, the present specification provides an evaporative emission control canister system comprising one or more canisters, the one or more canisters comprising: at least one fuel side particulate adsorbent volume comprising a particulate adsorbent having micropores with a diameter less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, a ratio of the volume of macropores to the volume of micropores greater than about 150%, and a retention of less than about 0.5 g / dL or a ratio of the volume of macropores to the volume of micropores greater than about 200% and a retention of less than about 1 g / dL; and at least one vent side particulate adsorbent volume comprising a particulate adsorbent having micropores with a diameter less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, a ratio of the volume of macropores to the volume of micropores greater than about 150%, wherein the at least one vent side particulate adsorbent volume has a butane retention of less than 0.5 g / dL or a ratio of the volume of macropores to the volume of micropores greater than about 200% and a retention of less than about 1 g / dL. In certain embodiments, the fuel side particulate adsorbent volume, the vent side particulate adsorbent volume, or both have a flow restriction property of less than 40 Pa / cm when an apparent linear air velocity of 46 cm / s is applied to a 43 mm diameter bed of the vent side particulate adsorbent volume. In further embodiments, the at least one fuel side particulate adsorbent volume, the at least one vent side particulate adsorbent volume, or both have a flow restriction of less than 0.3 kPa at an air flow rate of 40 lpm. In further embodiments, the at least one vent side particulate adsorbent volume has a length to diameter ratio of 2 or greater. In further embodiments, the at least one fuel side adsorbent volume has: a nominal BWC greater than 8 g / dL; a nominal IAC at 25 °C greater than 35 g / L between a vapor concentration of 5 vol% and 50 vol% n-butane; or both.

[0170] In certain embodiments, the low retention particulate adsorbent has a micropore volume of about 225 cc / L or less (about 0.5 cc / g or less). For example, the micropore volume of the low retention particulate adsorbent can be less than or equal to about 200 cc / L, less than or equal to about 175 cc / L, less than or equal to about 150 cc / L, less than or equal to about 125 cc / L, less than or equal to about 100 cc / L, less than or equal to about 75 cc / L, less than or equal to about 50 cc / L, or less than or equal to about 25 cc / L.As a further example, the micropore volume of the low retention rate particle adsorbent can be from about 1.0 cc / L to about 225 cc / L, from about 1.0 cc / L to about 200 cc / L, from about 1.0 cc / L to about 175 cc / L, from about 1.0 cc / L to about 150 cc / L, from about 1.0 cc / L to about 125 cc / L, from about 1.0 cc / L to about 100 cc / L, from about 1.0 cc / L to about 75 cc / L, from about 1.0 cc / L to about 50 cc / L, from about 1.0 cc / L to about 25 cc / L, from about 25 cc / L to about 225 cc / L, from about 25 cc / L to about 200 cc / L, from about 25 cc / L to about 175 cc / L, from about 25 cc / L to about 150 cc / L, from about 25 cc / L to about 125 cc / L, from about 25 cc / L to about 100 cc / L, from about 25 cc / L to about 75 cc / L, from about 25 cc / L to about 50 cc / L, from about 50 cc / L to about 225 cc / L, from about 50 cc / L to about 200 cc / L, from about 50 cc / L to about 175 cc / L, from about 50 cc / L to about 150 cc / L, from about 50 cc / L to about 125 cc / L, from about 50 cc / L to about 100 cc / L, from about 50 cc / L to about 75 cc / L, from about 75 cc / L to about 225 cc / L, from about 75 cc / L to about 200 cc / L, from about 75 cc / L to about 175 cc / L, from about 75 cc / L to about 150 cc / L, from about 75 cc / L to about 125 cc / L, from about 75 cc / L to about 100 cc / L, from about 100 cc / L to about 225 cc / L, from about 100 cc / L to about 200 cc / L, from about 100 cc / L to about 175 cc / L, from about 100 cc / L to about 150 cc / L, from about 100 cc / L to about 125 cc / L, from about 125 cc / L to about 225 cc / L, from about 125 cc / L to about 200 cc / L, from about 125 cc / L to about 175 cc / L, from about 125 cc / L to about 150 cc / L, from about 150 cc / L to about 225 cc / L, from about 150 cc / L to about 200 cc / L, from about 150 cc / L to about 175 cc / L, from about 175 cc / L to about 225 cc / L, from about 175 cc / L to about 200 cc / L or from about 200 cc / L to about 225 cc / L.

[0171] In some other embodiments, the low retention rate particulate adsorbent includes a body defining an outer surface and a three-dimensional low flow resistance shape or morphology. The three-dimensional low flow resistance shape or morphology can be any shape or morphology having a low flow resistance that would be contemplated by one of ordinary skill in the art. For example, the three-dimensional low flow resistance shape or morphology can be at least one of substantially cylindrical, substantially oval prism, substantially spherical, substantially cubic, substantially elliptical prism, substantially rectangular prism, leaf-shaped prism, three-dimensional helix or vortex, or a combination thereof. Other useful examples of the morphology include shapes known to those skilled in the art of absorber tower packing and include Raschig rings, cross partition rings, rings, saddle rings, berl saddles, Super saddle rings, conjugate rings, cascade rings, and Lessing rings. Other useful examples of the morphology include shapes known to those skilled in the art of pasta making and can include ribbon, solid, hollow, leaf-shaped, and leaf-shaped hollow composite shapes of strips, springs, coils, corkscrews, shells, tubes, such as fusilli, rotini, penne, macaroni, ribbed macaroni, slingshot pasta, bow tie pasta, elbow macaroni, casarecce, conchiglie, cockscomb pasta, lily pasta, snail pasta, wavy pasta, lasagna, wagon wheel pasta, small shells, or a combination thereof.

[0172] As a non-limiting example, Figures 3A to 3I illustrates exemplary shape morphologies of the present disclosure, including a composite leaf-shaped shape (A), a square prism shape (B), a cylindrical shape (C), a shape having a star-shaped cross-section (D), a cross-section (E), a triangular prism having an inner wall that traverses the central axis (F), a triangular prism having an inner wall that does not traverse the central axis (G), a helical or twisted ribbon shape (H1 and an upright view H2), and a hollow cylinder (I).

[0173] The low retention particulate adsorbent material can have a cross-sectional width of from about 1 mm to about 20 mm (e.g., about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm, or about 20 mm). In certain embodiments, the cross-sectional width of the low retention particulate adsorbent is from about 1 mm to about 18 mm, from about 1 mm to about 16 mm, from about 1 mm to about 14 mm, from about 1 mm to about 12 mm, from about 1 mm to about 10 mm, from about 1 mm to about 8 mm, from about 1 mm to about 6 mm, from about 1 mm to about 4 mm, from about 1 mm to about 3 mm, from about 2 mm to about 20 mm, from about 2 mm to about 18 mm, from about 2 mm to about 16 mm, from about 2 mm to about 14 mm, from about 2 mm to about 12 mm, from about 2 mm to about 10 mm, from about 2 mm to about 8 mm, from about 2 mm to about 6 mm, from about 2 mm to about 4 mm, from about 4 mm to about 20 mm, from about 4 mm to about 18 mm, from about 4 mm to about 16 mm, from about 4 mm to about 14 mm, from about 4 mm to about 12 mm, from about 4 mm to about 10 mm, from about 4 mm to about 8 mm, from about 4 mm to about 6 mm, from about 6 mm to about 20 mm, from about 6 mm to about 18 mm, from about 6 mm to about 16 mm, from about 6 mm to about 14 mm, from about 6 mm to about 12 mm, from about 6 mm to about 10 mm, from about 6 mm to about 8 mm, from about 8 mm to about 20 mm, from about 8 mm to about 18 mm, from about 8 mm to about 16 mm, from about 8 mm to about 14 mm, from about 8 mm to about 12 mm, from about 8 mm to about 10 mm, from about 10 mm to about 20 mm, from about 10 mm to about 18 mm, from about 10 mm to about 16 mm, from about 10 mm to about 14 mm, from about 10 mm to about 12 mm, from about 12 mm to about 20 mm, from about 12 mm to about 18 mm, from about 12 mm to about 16 mm, from about 12 mm to about 14 mm, from about 14 mm to about 20 mm, from about 14 mm to about 18 mm, from about 14 mm to about 16 mm, from about 16 mm to about 20 mm, from about 16 mm to about 18 mm, or from about 18 mm to about 20 mm.

[0174] The low retention particulate adsorbent can include at least one cavity in fluid communication with the outer surface of the adsorbent.

[0175] The low retention particulate adsorbent can have a cross-section of a hollow shape.

[0176] The low retention particulate adsorbent can include at least one channel in fluid communication with at least one outer surface.

[0177] In certain other embodiments, each portion of the low retention particulate adsorbent has a thickness equal to or less than about 3.0 mm. For example, each portion of the low retention particulate adsorbent can have a thickness equal to or less than 2.5 mm, equal to or less than 2.0 mm, equal to or less than 1.5 mm, equal to or less than 1.25 mm, equal to or less than 1.0 mm, equal to or less than 0.75 mm, equal to or less than 0.5 mm, or equal to or less than 0.25 mm. That is, each portion of the adsorbent can have a thickness of from about 0.1 mm to about 3 mm, from about 0.1 mm to about 2.5 mm, from about 0.1 mm to about 2.0 mm, from about 0.1 mm to about 1.5 mm, from about 0.1 mm to about 1.0 mm, from about 0.1 mm to about 0.5 mm, from about 0.2 mm to about 3 mm, from about 0.2 mm to about 2.5 mm, from about 0.2 mm to about 2.0 mm, from about 0.2 mm to about 1.5 mm, from about 0.2 mm to about 1.0 mm, from about 0.2 mm to about 0.5 mm, from about 0.4 mm to about 3 mm, from about 0.4 mm to about 2.5 mm, from about 0.4 mm to about 2.0 mm, from about 0.4 mm to about 1.5 mm, from about 0.4 mm to about 1.0 mm, from about 0.4 mm to about 3 mm, from about 0.4 mm to about 2.5 mm, from about 0.4 mm to about 2.0 mm, from about 0.4 mm to about 1.5 mm, from about 0.4 mm to about 1.0 mm, from about 0.75 mm to about 3 mm, from about 0.75 mm to about 2.5 mm, from about 0.75 mm to about 2.0 mm, from about 0.75 mm to about 1.5 mm, from about 0.75 mm to about 1.0 mm, from about 1.25 mm to about 3 mm, from about 1.25 mm to about 2.5 mm, from about 1.25 mm to about 2.0 mm, from about 2.0 mm to about 3 mm, from about 2.0 mm to about 2.5 mm, or from about 2.5 mm to about 3.0 mm.

[0178] In one embodiment, at least one outer wall of the hollow shape of the low retention particulate adsorbent has a thickness equal to or less than about 1.0 mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, or about 1.0 mm). For example, the outer wall of the hollow shape of the low retention particulate adsorbent can have a thickness in the range of about 0.1 mm to about 1.0 mm, about 0.1 mm to about 0.9 mm, about 0.1 mm to about 0.8 mm, about 0.1 mm to about 0.7 mm, about 0.1 mm to about 0.6 mm, about 0.1 mm to about 0.5 mm, about 0.1 mm to about 0.4 mm, about 0.1 mm to about 0.3 mm, about 0.1 mm to about 0.2 mm, about 0.2 mm to about 1.0 mm, about 0.2 mm to about 0.9 mm, about 0.2 mm to about 0.8 mm, about 0.2 mm to about 0.7 mm, about 0.2 mm to about 0.6 mm, about 0.2 mm to about 0.5 mm, about 0.2 mm to about 0.4 mm, about 0.2 mm to about 0.3 mm, about 0.3 mm to about 1.0 mm, about 0.3 mm to about 0.9 mm, about 0.3 mm to about 0.8 mm, about 0.3 mm to about 0.7 mm, about 0.3 mm to about 0.6 mm, about 0.3 mm to about 0.5 mm, about 0.3 mm to about 0.4 mm, about 0.4 mm to about 1.0 mm, about 0.4 mm to about 0.9 mm, about 0.4 mm to about 0.8 mm, about 0.4 mm to about 0.7 mm, about 0.4 mm to about 0.6 mm, about 0.4 mm to about 0.5 mm, about 0.5 mm to about 1.0 mm, about 0.5 mm to about 0.9 mm, about 0.5 mm to about 0.8 mm, about 0.5 mm to about 0.7 mm, about 0.5 mm to about 0.6 mm, about 0.6 mm to about 1.0 mm, about 0.6 mm to about 0.9 mm, about 0.6 mm to about 0.8 mm, about 0.6 mm to about 0.7 mm, about 0.7 mm to about 1.0 mm, about 0.7 mm to about 0.9 mm, about 0.7 mm to about 0.8 mm, about 0.8 mm to about 1.0 mm, about 0.8 mm to about 0.9 mm, or about 0.9 mm to about 1.0 mm.

[0179] In still other embodiments, the hollow shape of the low retention particulate adsorbent has at least one inner wall that extends between the outer walls and has a thickness equal to or less than about 1.0 mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, or about 1.0 mm). For example, the inner wall can have a thickness in the range of about 0.1 mm to about 1.0 mm, about 0.1 mm to about 0.9 mm, about 0.1 mm to about 0.8 mm, about 0.1 mm to about 0.7 mm, about 0.1 mm to about 0.6 mm, about 0.1 mm to about 0.5 mm, about 0.1 mm to about 0.4 mm, about 0.1 mm to about 0.3 mm, about 0.1 mm to about 0.2 mm, about 0.2 mm to about 1.0 mm, about 0.2 mm to about 0.9 mm, about 0.2 mm to about 0.8 mm, about 0.2 mm to about 0.7 mm, about 0.2 mm to about 0.6 mm, about 0.2 mm to about 0.5 mm, about 0.2 mm to about 0.4 mm, about 0.2 mm to about 0.3 mm, about 0.3 mm to about 1.0 mm, about 0.3 mm to about 0.9 mm, about 0.3 mm to about 0.8 mm, about 0.3 mm to about 0.7 mm, about 0.3 mm to about 0.6 mm, about 0.3 mm to about 0.5 mm, about 0.3 mm to about 0.4 mm, about 0.4 mm to about 1.0 mm, about 0.4 mm to about 0.9 mm, about 0.4 mm to about 0.8 mm, about 0.4 mm to about 0.7 mm, about 0.4 mm to about 0.6 mm, about 0.4 mm to about 0.5 mm, about 0.5 mm to about 1.0 mm, about 0.5 mm to about 0.9 mm, about 0.5 mm to about 0.8 mm, about 0.5 mm to about 0.7 mm, about 0.5 mm to about 0.6 mm, about 0.6 mm to about 1.0 mm, about 0.6 mm to about 0.9 mm, about 0.6 mm to about 0.8 mm, about 0.6 mm to about 0.7 mm, about 0.7 mm to about 1.0 mm, about 0.7 mm to about 0.9 mm, about 0.7 mm to about 0.8 mm, about 0.8 mm to about 1.0 mm, about 0.8 mm to about 0.9 mm, or about 0.9 mm to about 1.0 mm.

[0180] In certain embodiments, the thickness of at least one of the inner wall, outer wall, or a combination thereof of the low retention particulate adsorbent may be equal to or less than about 1.0 mm (e.g., about 0.1 mm, about 0.2 mm, about 0.3 mm, about 0.4 mm, about 0.5 mm, about 0.6 mm, about 0.7 mm, about 0.8 mm, about 0.9 mm, or about 1.0 mm). For example, the thickness of at least one of the inner wall, outer wall, or a combination thereof of the low retention particulate adsorbent is equal to or less than about 1.0 mm, equal to or less than about 0.6 mm, or equal to or less than about 0.4 mm. In some embodiments, at least one of the inner wall, outer wall, or a combination thereof of the low retention particulate adsorbent has a thickness in the range of from about 0.1 mm to about 1.0 mm, from about 0.1 mm to about 0.9 mm, from about 0.1 mm to about 0.8 mm, from about 0.1 mm to about 0.7 mm, from about 0.1 mm to about 0.6 mm, from about 0.1 mm to about 0.5 mm, from about 0.1 mm to about 0.4 mm, from about 0.1 mm to about 0.3 mm, from about 0.1 mm to about 0.2 mm, from about 0.2 mm to about 1.0 mm, from about 0.2 mm to about 0.9 mm, from about 0.2 mm to about 0.8 mm, from about 0.2 mm to about 0.7 mm, from about 0.2 mm to about 0.6 mm, from about 0.2 mm to about 0.5 mm, from about 0.2 mm to about 0.4 mm, from about 0.2 mm to about 0.3 mm, from about 0.3 mm to about 1.0 mm, from about 0.3 mm to about 0.9 mm, from about 0.3 mm to about 0.8 mm, from about 0.3 mm to about 0.7 mm, from about 0.3 mm to about 0.6 mm, from about 0.3 mm to about 0.5 mm, from about 0.4 mm to about 1.0 mm, from about 0.4 mm to about 0.9 mm, from about 0.4 mm to about 0.8 mm, from about 0.4 mm to about 0.7 mm, from about 0.4 mm to about 0.6 mm, from about 0.4 mm to about 0.5 mm, from about 0.5 mm to about 1.0 mm, from about 0.5 mm to about 0.9 mm, from about 0.5 mm to about 0.8 mm, from about 0.5 mm to about 0.7 mm, from about 0.5 mm to about 0.6 mm, from about 0.6 mm to about 1.0 mm, from about 0.6 mm to about 0.9 mm, from about 0.6 mm to about 0.8 mm, from about 0.6 mm to about 0.7 mm, from about 0.7 mm to about 1.0 mm, from about 0.7 mm to about 0.9 mm, from about 0.7 mm to about 0.8 mm, from about 0.8 mm to about 1.0 mm, from about 0.8 mm to about 0.9 mm, or from about 0.9 mm to about 1.0 mm.

[0181] In some embodiments, the inner wall of the low retention particulate adsorbent extends outwardly from the hollow portion (such as from the center) of the particulate adsorbent material in at least two directions to the outer wall.

[0182] For example, the inner wall of the low retention particulate adsorbent can extend outwardly from the hollow portion of the particulate adsorbent material (such as from the center of the particulate adsorbent material) in at least three directions or from the hollow portion of the particulate adsorbent material (such as from the center of the particulate adsorbent material) in at least four directions to the outer wall.

[0183] In certain embodiments, the low retention particulate adsorbent material can have a length of from about 1 mm to about 20 mm (e.g., about 1 mm, about 2 mm, about 3 mm, about 4 mm, about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 11 mm, about 12 mm, about 13 mm, about 14 mm, about 15 mm, about 16 mm, about 17 mm, about 18 mm, about 19 mm or about 20 mm). In specific embodiments, the length of the low retention particulate adsorbent is from about 1 mm to about 18 mm, from about 1 mm to about 16 mm, from about 1 mm to about 14 mm, from about 1 mm to about 12 mm, from about 1 mm to about 10 mm, from about 1 mm to about 8 mm, from about 1 mm to about 6 mm, from about 1 mm to about 4 mm, from about 1 mm to about 3 mm, from about 2 mm to about 20 mm, from about 2 mm to about 18 mm, from about 2 mm to about 16 mm, from about 2 mm to about 14 mm, from about 2 mm to about 12 mm, from about 2 mm to about 10 mm, from about 2 mm to about 8 mm, from about 2 mm to about 6 mm, from about 4 mm to about 20 mm, from about 4 mm to about 18 mm, from about 4 mm to about 16 mm, from about 4 mm to about 14 mm, from about 4 mm to about 12 mm, from about 4 mm to about 10 mm, from about 4 mm to about 8 mm, from about 4 mm to about 6 mm, from about 6 mm to about 20 mm, from about 6 mm to about 18 mm, from about 6 mm to about 16 mm, from about 6 mm to about 14 mm, from about 6 mm to about 12 mm, from about 6 mm to about 10 mm, from about 6 mm to about 8 mm, from about 8 mm to about 20 mm, from about 8 mm to about 18 mm, from about 8 mm to about 16 mm, from about 8 mm to about 14 mm, from about 8 mm to about 12 mm, from about 8 mm to about 10 mm, from about 10 mm to about 20 mm, from about 10 mm to about 18 mm, from about 10 mm to about 16 mm, from about 10 mm to about 14 mm, from about 10 mm to about 12 mm, from about 12 mm to about 20 mm, from about 12 mm to about 18 mm, from about 12 mm to about 16 mm, from about 12 mm to about 14 mm, from about 14 mm to about 20 mm, from about 14 mm to about 18 mm, from about 14 mm to about 16 mm, from about 16 mm to about 20 mm, from about 16 mm to about 18 mm or from about 18 mm to about 20 mm.

[0184] The low retention particulate adsorbent can also include at least one of the following: a pore-forming material or processing aid that sublimes, evaporates, chemically decomposes, dissolves or melts when heated to 100 °C or higher; a binder; a filler; or a combination thereof.

[0185] In certain embodiments, the low retention particulate adsorbent comprises at least one of the following: about 5% to about 60% adsorbent, about 60% or less filler, about 6% or less pore-forming material (or processing aid), about 10% or less silicate, about 5% to about 70% clay, or combinations thereof. The low retention particulate adsorbent may be present in an amount of about 5% to about 60%, about 5% to about 50%, about 5% to about 40%, about 5% to about 30%, about 5% to about 20%, about 5% to about 10%, about 10% to about 60%, about 10% to about 50%, about 10% to about 40%, about 10% to about 30%, about 10% to about 20%, about 20% to about 60%, about 20% to about 50%, about 20% to about 40%, about 20% to about 30%, about 30% to about 60%, about 30% to about 50%, about 30% to about 40%, about 40% to about 60%, about 40% to about 50%, or about 50% to about 60% of the particulate adsorbent material.

[0186] The filler may be present in the low retention particulate adsorbent in an amount less than or equal to about 60%, less than or equal to about 50%, less than or equal to about 40%, less than or equal to about 30%, less than or equal to about 20%, less than or equal to about 10%, about 5% to about 60%, about 5% to about 50%, about 5% to about 40%, about 5% to about 30%, about 5% to about 20%, about 5% to about 10%, about 10% to about 60%, about 10% to about 50%, about 10% to about 40%, about 10% to about 30%, about 10% to about 20%, about 20% to about 60%, about 20% to about 50%, about 20% to about 40%, about 20% to about 30%, about 30% to about 60%, about 30% to about 50%, about 30% to about 40%, about 40% to about 60%, about 40% to about 50%, or about 50% to about 60% of the particulate adsorbent material.

[0187] The pore-forming material of the low retention particulate adsorbent may be present in an amount of about 6%, about 5%, about 4%, about 3%, about 2%, or about 1% of the particulate adsorbent material.

[0188] The silicate of the low retention particulate adsorbent may be present in an amount of about 10%, about 9%, about 8%, about 7%, about 6%, about 5%, about 4%, about 3%, about 2%, or about 1% of the particulate adsorbent material.

[0189] The clay of the low retention rate particle adsorbent can be present in an amount of about 5% to about 70%, 5% to about 60%, about 5% to about 50%, about 5% to about 40%, about 5% to about 30%, about 5% to about 20%, about 5% to about 10%, about 10% to about 70%, about 10% to about 60%, about 10% to about 50%, about 10% to about 40%, about 10% to about 30%, about 10% to about 20%, about 20% to about 70%, about 20% to about 60%, about 20% to about 50%, about 20% to about 40%, about 20% to about 30%, about 30% to about 70%, about 30% to about 60%, about 30% to about 50%, about 30% to about 40%, about 40% to about 70%, about 40% to about 60%, about 40% to about 50%, about 50% to about 70%, about 50% to about 60%, or about 60% to about 70% of the particle adsorbent material.

[0190] The pore-forming material (or processing aid) of the low-retention particulate adsorbent creates macropores upon sublimation, evaporation, chemical decomposition, dissolution, or melting. This provides spatial dilution of the low-retention particulate adsorbent material. The pore-forming material can be a cellulose derivative, such as methylcellulose, carboxymethylcellulose, polyethylene glycol, phenolic resin (phenolic varnish, resol), polyethylene, or polyester resin. The cellulose derivative can include copolymers having methyl groups and / or partial substitution with hydroxypropyl and / or hydroxyethyl groups. For example, when heated to a temperature in the range of about 125 °C to about 640 °C, the pore-forming material of the processing aid can sublime, evaporate, chemically decompose, dissolve, or melt.For example, when heated to a temperature in the range of about 125°C to about 600°C, about 125°C to about 550°C, about 125°C to about 500°C, about 125°C to about 450°C, about 125°C to about 400°C, about 125°C to about 350°C, about 125°C to about 300°C, about 125°C to about 250°C, about 125°C to about 200°C, about 125°C to about 150°C, about 150°C to about 640°C, about 150°C to about 600°C, about 150°C to about 550°C, about 150°C to about 500°C, about 150°C to about 450°C, about 150°C to about 400°C, about 150°C to about 350°C, about 150°C to about 300°C, about 150°C to about 250°C, about 150°C to about 200°C, about 200°C to about 640°C, about 200°C to about 600°C, about 200°C to about 550°C, about 200°C to about 500°C, about 200°C to about 450°C, about 200°C to about 400°C, about 200°C to about 350°C, about 200°C to about 300°C, about 200°C to about 250°C, about 250°C to about 640°C, about 250°C to about 600°C, about 250°C to about 550°C, about 250°C to about 500°C, about 250°C to about 450°C, about 250°C to about 400°C, about 250°C to about 350°C, about 250°C to about 300°C, about 300°C to about 640°C, about 300°C to about 600°C, about 300°C to about 550°C, about 300°C to about 500°C, about 300°C to about 450°C, about 300°C to about 400°C, about 300°C to about 350°C, about 350°C to about 640°C, about 350°C to about 600°C, about 350°C to about 550°C, about 350°C to about 500°C, about 350°C to about 450°C, about 350°C to about 400°C, about 400°C to about 640°C, about 400°C to about 600°C, about 400°C to about 550°C, about 400°C to about 500°C, about 400°C to about 450°C, about 450°C to about 640°C, about 450°C to about 600°C, about 450°C to about 550°C, about 450°C to about 500°C, about 500°C to about 640°C, about 500°C to about 600°C, about 500°C to about 550°C, about 550°C to about 640°C, about 550°C to about 600°C or about 600°C to about 640°C, the processing aids of the low retention rate particulate adsorbent can sublime, evaporate, chemically decompose, dissolve or melt.

[0191] The binder of the low retention rate particulate adsorbent can be a clay or a silicate material. For example, the binder of the low retention rate particulate adsorbent can be at least one of zeolite clay, bentonite clay, montmorillonite clay, illite clay, French green clay, Pascallite clay, Redmond clay, Terramin clay, activated clay, fuller's earth clay, Ormalite clay, Vitalite clay, rectorite clay, cordierite, ball clay, kaolin or a combination thereof.

[0192] Fillers for low retention particulate adsorbents can function within the particulate adsorbent structure to aid in and maintain shape formation and mechanical integrity and to increase the amount of macropore volume in the final particulate product. In one embodiment, the filler for the low retention particulate adsorbent is a solid or hollow microsphere, which can be micron sized or larger. In other embodiments, the filler for the low retention particulate adsorbent is an inorganic filler such as a glass material and / or a ceramic material. The filler for the low retention particulate adsorbent can be any suitable filler that provides the above benefits as would be understood by one of ordinary skill in the art.

[0193] A low retention particulate adsorbent material can be prepared by admixing an adsorbent having micropores with a diameter of less than about 100 nm and a pore forming material or processing aid that sublimes, evaporates, chemically decomposes, dissolves, or melts when heated to 100 °C or higher; and heating the mixture to a temperature range of about 100 °C to about 1200 °C for about 0.25 hours to about 24 hours such that macropores having a diameter of about 100 to 100,000 nm are formed when the core material sublimes, evaporates, chemically decomposes, dissolves, or melts, wherein the ratio of the volume of macropores to the volume of micropores in the adsorbent is greater than 150%. The adsorbent can have any of the characteristics of the low retention particulate adsorbent materials discussed throughout this disclosure.

[0194] The mixture can be heated to about 100°C to about 1200°C, about 100°C to about 1000°C, about 100°C to about 900°C, about 100°C to about 800°C, about 100°C to about 700°C, about 100°C to about 600°C, about 100°C to about 500°C, about 100°C to about 400°C, about 100°C to about 300°C, about 100°C to about 200°C, about 200°C to about 1200°C, about 200°C to about 1100°C, about 200°C to about 1000°C, about 200°C to about 900°C, about 200°C to about 800°C, about 200°C to about 700°C, about 200°C to about 600°C, about 200°C to about 500°C, about 200°C to about 400°C, about 200°C to about 300°C, about 300°C to about 1200°C, about 300°C to about 1100°C, about 300°C to about 1000°C, about 300°C to about 900°C, about 300°C to about 800°C, about 300°C to about 700°C, about 300°C to about 600°C, about 300°C to about 500°C, about 300°C to about 400°C, about 400°C to about 1200°C, about 400°C to about 1100°C, about 400°C to about 1000°C, about 400°C to about 900°C, about 400°C to about 800°C, about 400°C to about 700°C, about 400°C to about 600°C, about 400°C to about 500°C, about 500°C to about 1200°C, about 500°C to about 1100°C, about 500°C to about 1000°C, about 500°C to about 900°C, about 500°C to about 800°C, about 500°C to about 700°C, about 500°C to about 600°C, about 600°C to about 1200°C, about 600°C to about 1100°C, about 600°C to about 1000°C, about 600°C to about 900°C, about 600°C to about 800°C, about 600°C to about 700°C, about 700°C to about 1200°C, about 700°C to about 1100°C, about 700°C to about 1000°C, about 700°C to about 900°C, about 700°C to about 800°C, about 800°C to about 1200°C, about 800°C to about 1100°C, about 800°C to about 1000°C, about 800°C to about 900°C, about 900°C to about 1200°C, about 900°C to about 1100°C, about 900°C to about 1000°C, about 1000°C to about 1200°C, about 1000°C to about 1100°C or about 1100°C to about 1200°C.

[0195] In some embodiments, the heating mixture may include a heating rate of about 2.5 °C / minute, about 1.0 °C / minute, about 1.25 °C / minute, about 1.5 °C / minute, about 1.75 °C / minute, about 2.0 °C / minute, about 2.25 °C / minute, about 2.75 °C / minute, about 3.0 °C / minute, about 3.25 °C / minute, about 3.5 °C / minute, about 3.75 °C / minute, about 4.0 °C / minute or 4.25 °C / minute. For example, the heating rate may be from about 0.5 °C / minute to about 20 °C / minute, from about 0.5 °C / minute to about 15 °C / minute, from about 0.5 °C / minute to about 10 °C / minute, from about 0.5 °C / minute to about 5.0 °C / minute, from about 0.5 °C / minute to about 2.5 °C / minute, from about 1.0 °C / minute to about 20 °C / minute, from about 1.0 °C / minute to about 15 °C / minute, from about 1.0 °C / minute to about 10 °C / minute, from about 1.0 °C / minute to about 5.0 °C / minute, from about 1.0 °C / minute to about 2.5 °C / minute, from about 2.0 °C / minute to about 20 °C / minute, from about 2.0 °C / minute to about 15 °C / minute, from about 2.0 °C / minute to about 10 °C / minute, from about 2.0 °C / minute to about 5.0 °C / minute, from about 2.0 °C / minute to about 2.5 °C / minute, from about 5.0 °C / minute to about 20 °C / minute, from about 5.0 °C / minute to about 15 °C / minute, from about 5.0 °C / minute to about 10 °C / minute, from about 10 °C / minute to about 20 °C / minute, from about 10 °C / minute to about 15 °C / minute or from about 15 °C / minute to about 20 °C / minute. In certain embodiments, the heating rate is from about 20 °C / minute to about 100 °C / minute, 30 °C / minute to about 100 °C / minute, 40 °C / minute to about 100 °C / minute, 50 °C / minute to about 100 °C / minute, 60 °C / minute to about 100 °C / minute, 70 °C / minute to about 100 °C / minute, 80 °C / minute to about 100 °C / minute or 90 °C / minute to about 100 °C / minute.

[0196] For example, the temperature rise may take from about 5 minutes to about 2 hours, about 5 minutes to about 1.75 hours, about 5 minutes to about 1.5 hours, about 5 minutes to about 1.25 hours, about 5 minutes to about 1.0 hour, about 5 minutes to about 45 minutes, about 5 minutes to about 30 minutes, about 5 minutes to about 15 minutes, about 15 minutes to about 2 hours, about 15 minutes to about 1.75 hours, about 15 minutes to about 1.5 hours, about 15 minutes to about 1.25 hours, about 15 minutes to about 1.0 hour, about 15 minutes to about 45 minutes, about 15 minutes to about 30 minutes, about 30 minutes to about 2 hours, about 30 minutes to about 1.75 hours, about 30 minutes to about 1.5 hours, about 30 minutes to about 1.25 hours, about 30 minutes to about 1.0 hour, about 30 minutes to about 45 minutes, about 45 minutes to about 2 hours, about 45 minutes to about 1.75 hours, about 45 minutes to about 1.5 hours, about 45 minutes to about 1.25 hours, about 45 minutes to about 1.0 hour, about 1.0 hour to about 2 hours, about 1.0 hour to about 1.75 hours, about 1.0 hour to about 1.5 hours, about 1.0 hour to about 1.25 hours, about 1.25 hours to about 2 hours, about 1.25 hours to about 1.75 hours, about 1.25 hours to about 1.5 hours, about 1.5 hours to about 2 hours, about 1.5 hours to about 1.75 hours, or about 1.75 hours to about 2.0 hours.

[0197] In another embodiment, the mixture is maintained at this temperature (i.e., after heating up) for about 0.25 hours to about 24 hours. For example, the mixture can be maintained at this temperature for about 0.25 hours to about 18 hours, about 0.25 hours to about 16 hours, about 0.25 hours to about 14 hours, about 0.25 hours to about 12 hours, about 0.25 hours to about 10 hours, about 0.25 hours to about 8 hours, about 0.25 hours to about 6 hours, about 0.25 hours to about 4 hours, about 0.25 hours to about 2 hours, about 1 hour to about 24 hours, about 0.25 hours to about 18 hours, about 1 hour to about 16 hours, about 1 hour to about 14 hours, about 1 hour to about 12 hours, about 1 hour to about 10 hours, about 1 hour to about 8 hours, about 1 hour to about 6 hours, about 1 hour to about 4 hours, about 1 hour to about 2 hours, about 2 hours to about 24 hours, about 2 hours to about 18 hours, about 2 hours to about 16 hours, about 2 hours to about 14 hours, about 2 hours to about 12 hours, about 2 hours to about 10 hours, about 2 hours to about 8 hours, about 2 hours to about 6 hours, about 2 hours to about 3 hours, about 3 hours to about 24 hours, about 3 hours to about 18 hours, about 3 hours to about 16 hours, about 3 hours to about 14 hours, about 3 hours to about 12 hours, about 3 hours to about 10 hours, about 3 hours to about 8 hours, about 3 hours to about 6 hours, about 3 hours to about 4 hours, about 4 hours to about 24 hours, about 4 hours to about 18 hours, about 4 hours to about 16 hours, about 4 hours to about 14 hours, about 4 hours to about 12 hours, about 4 hours to about 10 hours, about 4 hours to about 8 hours, about 4 hours to about 6 hours, about 6 hours to about 24 hours, about 6 hours to about 18 hours, about 6 hours to about 16 hours, about 6 hours to about 14 hours, about 6 hours to about 12 hours, about 6 hours to about 10 hours, about 6 hours to about 8 hours, about 8 hours to about 24 hours, about 8 hours to about 18 hours, about 8 hours to about 16 hours, about 8 hours to about 14 hours, about 8 hours to about 12 hours, about 8 hours to about 10 hours, about 10 hours to about 24 hours, about 10 hours to about 18 hours, about 10 hours to about 16 hours, about 10 hours to about 14 hours, about 10 hours to about 12 hours, about 12 hours to about 24 hours, about 12 hours to about 18 hours, about 12 hours to about 16 hours, about 12 hours to about 14 hours, about 14 hours to about 24 hours, about 14 hours to about 18 hours, about 14 hours to about 16 hours, about 16 hours to about 24 hours, about 16 hours to about 18 hours, about 18 hours to about 24 hours, about 18 hours to about 22 hours, about 18 hours to about 20 hours, about 20 hours to about 24 hours, about 20 hours to about 22 hours or about 22 hours to about 24 hours.

[0198] The method of preparing the low retention rate particulate adsorbent may also include cooling the mixture (e.g., cooling to about room temperature). In one embodiment, the mixture may be cooled for about 0.5 to about 10 hours. For example, the mixture may be cooled for about 0.5 hours to about 9 hours, about 0.5 hours to about 8 hours, about 0.5 hours to about 7 hours, about 0.5 hours to about 6 hours, about 0.5 hours to about 5 hours, about 0.5 hours to about 4 hours, about 0.5 hours to about 3 hours, about 0.5 hours to about 2 hours, about 0.5 hours to about 1 hour, about 5 hours to about 10 hours, about 5 hours to about 9 hours, about 5 hours to about 8 hours, about 5 hours to about 7 hours, about 5 hours to about 6 hours, about 6 hours to about 10 hours, about 6 hours to about 9 hours, about 6 hours to about 8 hours, about 6 hours to about 7 hours, about 7 hours to about 10 hours, about 7 hours to about 9 hours, about 7 hours to about 8 hours, about 8 hours to about 10 hours, about 8 hours to about 9 hours, or about 9 hours to about 10 hours.

[0199] The heating of the mixture to prepare the low retention rate particulate adsorbent may be carried out in an inert atmosphere (e.g., nitrogen, argon, neon, krypton, xenon, radon, flue gas in which the steam and oxygen contents are controlled, or a combination thereof).

[0200] The low retention rate particulate adsorbent material may have a retention rate of about 1.0 g / dL or less, about 0.75 g / dL or less, about 0.50 g / dL or less, or about 0.25 g / dL or less. For example, the low retention rate adsorbent may have a retention rate of about 0.25 g / dL to about 1.00 g / dL, about 0.25 g / dL to about 0.75 g / dL, about 0.25 g / dL to about 0.50 g / dL, about 0.50 g / dL to about 1.00 g / dL, about 0.50 g / dL to about 0.75 g / dL, or about 0.75 g / dL to about 1.00 g / dL.

[0201] In any aspect or embodiment described herein, at least one of the following is satisfied: the diameter of the micropores of the low retention rate adsorbent is less than about 100 nm; the diameter of the macropores is equal to or greater than 100 nm and less than 100,000 nm; or a combination thereof.

[0202] The method of preparing a low retention particulate adsorbent may also include extruding or compressing the admixture into a shaped structure. For example, the extruded or compressed low retention particulate adsorbent material may include a body defining an outer surface and a three-dimensional low flow resistance shape or morphology. The low flow resistance shape or morphology of the low retention particulate adsorbent may be any shape or morphology of the adsorbent material described herein, for example. For example, the three-dimensional low flow resistance shape or morphology of the low retention particulate adsorbent may be substantially cylindrical, substantially ovoid prismatic, substantially spherical, substantially cubic, substantially elliptical prismatic, substantially rectangular prismatic, leaf-shaped prismatic, three-dimensional helix, Figures 3A to 3I at least one of the shapes or morphologies shown or a combination thereof.

[0203] The adsorbent of the low retention particulate adsorbent may be at least one of activated carbon, molecular sieve, porous alumina, clay, porous silica, zeolite, metal organic framework or a combination thereof.

[0204] The mixture of the low retention particulate adsorbent may also include a binder (such as clay, silicate or a combination thereof) and / or a filler. The filler may be any filler known or known in the relevant art.

[0205] The low retention particulate adsorbent may have a cross-sectional width in the range of about 1 mm to about 20 mm.

[0206] The low retention particulate adsorbent material may include at least one cavity or channel in fluid communication with the outer surface of the adsorbent. The low retention particulate adsorbent may have a cross-section of a hollow shape. Each part of the low retention particulate adsorbent may have a thickness of about 3.0 mm or less. The outer wall of the hollow shape may have a thickness of 3 mm or less (for example, about 0.1 mm to about 1.0 mm). The hollow shape may have an inner wall extending between the outer walls, and the inner wall may have a thickness of, for example, about 3.0 mm or less (for example, about 0.1 mm to about 1.0 mm).

[0207] The inner wall may extend outward from the inner volume (such as from the hollow part) such as the center in at least two directions, at least three directions or at least four directions to the outer wall.

[0208] In some embodiments, the low retention particulate adsorbent has a length of about 1 mm to about 20 mm (for example, about 2 mm to about 7 mm).

[0209] Method

[0210] In a further aspect, the present disclosure provides a method for reducing fuel vapor emissions in an evaporative emission control system, the method comprising contacting fuel vapor with at least one volume of a vent-side particulate adsorbent comprising at least one of: micropores having a diameter less than or equal to about 100 nm, macropores having a diameter of about 100 to 100,000 nm, and a ratio (M / m) of the volume of macropores to the volume of micropores greater than about 150%, wherein the at least one vent-side particulate adsorbent volume has a butane retention rate of from about 1 g / dL to about 0.25 g / dL or less, a particle diameter of from 3 to 6 mm, or both.

[0211] In some embodiments, the method further comprises contacting the fuel vapor with at least one fuel-side adsorbent volume as described herein, such as the high BWC, high IAC adsorbent volume described herein, prior to the fuel vapor contacting the at least one vent-side particulate adsorbent described herein.

[0212] In any aspect or embodiment described herein, the adsorbent is located within a single canister. In a particular embodiment, the adsorbent is located within a plurality of canisters, the plurality of canisters being connected to allow sequential contact by the fuel vapor.

[0213] In a further embodiment, the method may comprise contacting the fuel vapor with the high butane working capacity adsorbent volume described herein prior to the fuel vapor contacting the vent-side low retention particulate adsorbent volume. That is, the high butane working capacity adsorbent is located upstream of the low retention particulate adsorbent in the fuel vapor flow path. For example, if the vent-side low retention particulate adsorbent volume is present in volume 204 of the main canister, the high butane working capacity adsorbent may be present in at least one of volumes 203, 202, 201 of the main canister or a combination thereof. Similarly, if the supplemental canister includes a vent-side low retention particulate adsorbent volume, the high butane working capacity adsorbent may be located in at least one volume of the main canister 201 to 204 and / or at least one volume of the supplemental canister upstream or prior to the vent-side low retention particulate adsorbent volume of the supplemental canister. For example, if the vent-side low retention particulate adsorbent volume is present in volume 304, the high butane working capacity adsorbent may be present in at least one volume selected from 201 to 204, 301 to 303, or a combination thereof. Those skilled in the art will appreciate that there are many other configurations that satisfy this feature. For example, in one embodiment, the main canister (such as in at least one of volumes 201 to 204 or a combination thereof) includes the high butane working capacity adsorbent, while the supplemental canister (such as in at least one of volumes 301 to 305 or a combination thereof) includes the high butane adsorbent.

[0214] The method may further include contacting the fuel vapor with an additional vent side particulate adsorbent volume (e.g., a vent side low retention particulate adsorbent volume that is downstream or subsequent to another in a fluid or vapor path), wherein the vent side subsequent adsorbent has micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, and a ratio of the volume of the macropores to the volume of the micropores that is equal to or less than about 150%. For example, if the volume 203 of the main tank includes a low retention particulate adsorbent, the downstream vent side subsequent adsorbent volume may be present in the volume 204 of the main tank, at least one of the volumes of the refill tanks 301 to 305, or a combination thereof. For example, in a particular embodiment, the low retention particulate adsorbent is present on the main tank side of the refill tank (e.g., 301 to 303), and the downstream / subsequent adsorbent volume is present on the vent side of the refill tank (e.g., volumes 304 and 305).

[0215] Thus, in certain embodiments, the method includes contacting a high butane working capacity adsorbent / volume, a low retention adsorbent / volume, and a subsequent adsorbent / volume, in that order, with fuel vapor from a fuel vapor inlet.

[0216] Thus, in certain embodiments, the method includes contacting a high butane working capacity adsorbent / volume, a low retention adsorbent / volume, and a subsequent adsorbent / volume, in that order, with fuel vapor from a fuel vapor inlet.

[0217] The adsorbent suitable for use in the adsorbent volume may be derived from many different materials and in various forms. It may be a single component or a mixture of different components. Additionally, the adsorbent (as a single component or a mixture of different components) may include a volume diluent. Non-limiting examples of volume diluents may include, but are not limited to, spacers, inert voids, foams, fibers, springs, or combinations thereof.

[0218] Examples

[0219] Determination of Apparent Density

[0220] The standard method ASTM D 2854-09 (2014) (hereinafter referred to as the "standard method") can be used to determine the apparent density of the particulate adsorbent, considering a specified minimum ratio of 10 of the graduated cylinder diameter to the average particle diameter of the particulate material, where the average particle diameter is measured according to a specified standard screening method.

[0221] Determination of Macropore Volume

[0222] The macro - pore volume was measured by mercury intrusion porosimetry ISO 15901 - 1:2016. The equipment used for the examples was a Micromeritics Autopore V (Norcross, GA). The size of the samples used was approximately 0.4 g and they were pre - treated in an oven at 105 °C for at least 1 hour. The mercury surface tension and contact angle used in the Washburn equation were 485 dynes / cm and 130°, respectively. The macro - pores referred to herein are those with diameters from approximately 100 nm to approximately 100000 nm.

[0223] Determination of the micro - pore volume

[0224] The micro - pore volume was measured by nitrogen adsorption porosimetry obtained by the nitrogen adsorption method ISO 15901 - 2:2006 using a Micromeritics ASAP2420 (Norcross, GA). The micro - pores referred to herein are pores with diameters less than approximately 100 nm. The sample preparation procedure was degassing to a pressure less than 10 mHg. The determination of the pore volume of the micro - pore size was from the desorption branch of the 77 K isotherm of a 0.1 g sample. The nitrogen adsorption isotherm data was analyzed by the Kelvin and Halsey equations to determine the pore volume distribution of pore sizes with cylindrical pores according to the Barrett, Joyner, and Halenda (“BJH”) model. The non - ideal factor was 0.0000620. The density conversion factor was 0.0015468. The hard - sphere diameter for thermal transpiration was The molecular cross - sectional area was 0.162 nm 2 。For the calculation, the condensation layer thickness related to the pore diameter was 0.4977[ln(D)] 2 - 0.6981ln(D)+2.5074. The target relative pressures for the isotherm were as follows: 0.04, 0.05, 0.085, 0.125, 0.15, 0.18, 0.2, 0.355, 0.5, 0.63, 0.77, 0.9, 0.95, 0.995, 0.95, 0.9, 0.8, 0.7, 0.6, 0.5, 0.45, 0.4, 0.35, 0.3, 0.25, 0.2, 0.15, 0.12, 0.1, 0.07, 0.05, 0.03, 0.01. The actual points recorded were within a pressure tolerance of 5 mmHg or 5% absolute or relative pressure, whichever was more stringent. The time between consecutive pressure readings during equilibration was 10 seconds.

[0225] Determination of the adsorbent volume diameter

[0226] The diameter D of the adsorbent volume is the "equivalent circle diameter" and is derived from the volume V of the adsorbent volume and the vapor path length L. The diameter D is calculated as (4V / πL) 1 / 2 The equivalent circle size of. For example, as a general illustration of the calculation, an adsorbent volume of 200 cc has a vapor path length of 10 cm. The diameter is [(4 x 200) / (10π)] 1 / 2 = 5.0 cm. Thus, L / D is 10 cm / 5 cm = 2.0.

[0227] Determination of Flow Restriction

[0228] Using Figure 4 the apparatus shown, the flow restriction is measured as the pressure drop (Pa / cm) across a 30 mm long densely packed bed of adsorbent particles of different shapes at a given standard liters per minute (slpm). Specifically, for an air flow range of 10 to 70 slpm (11.5 to 80.3 cm / s), the pressure drop (Pa / cm) across a 30 mm depth is measured at the center of a bed of pellets with a 43 mm diameter. According to ASTM procedure D2854, the adsorbent is loaded into a 43 mm inner diameter tube that has an orifice drilled + / - 15 mm measured from the midpoint along the bed length. Open cell foam is used to contain the carbon bed. For pressure purging, compressed air is loaded through orifice 1 into the atmosphere at orifice 2; the pressure drop across orifices 3 and 4 is measured. For vacuum purging, a vacuum is drawn through orifice 1; the pressure drop across orifices 3 and 4 is measured. The flow rate is adjusted from 10 to 70 slpm (11.5 to 80.3 cm / s) and the pressure drop is measured each time it is adjusted. For monoliths, the pressure drop (Pa / cm) is measured from 10 to 70 slpm of the monolith. For a 35 mm diameter monolith, the pressure drop at 46 cm / s is approximately estimated from the measurement at 30 lpm flow rate, while for a 29 mm diameter monolith, the pressure drop at 46 cm / s is approximately estimated from the measurement at 20 lpm flow rate.

[0229] Component flow restrictions (such as Figure 4 between orifice 1 and orifice 2) are measured as the pressure drop (kPa) of the component in the housing for canister testing. The flow restriction of the component housing is also measured without the adsorbent. The flow rate is adjusted from 10 to 70 SLPM (11.5 to 80.3 cm / s) and the pressure drop is measured each time it is adjusted. The pressure drop of the adsorbent bed or monolith component is recorded in kPa and the housing pressure drop at the same flow rate is corrected.

[0230] For the adsorbent bed inside the canister, the pressure drop is calculated by first determining the basic Pa / cm vs. cm / s relationship curve for a 43 x 110 mm bed in a 43 mm inner diameter (ID) auxiliary tube as described above, as described above and as Figure 25 and Figure 30As shown. Then, by using the average hydraulic diameter calculated above, the Pa / cm of the adsorbent bed at a given flow rate in cm / s is then determined, and then multiplied by the calculated bed length to calculate the pressure drop at 40 LPM. The length of the bed is determined to be the volume divided by the average cross-sectional area of the canister bed section.

[0231] As used herein, the term "total nominal volume" refers to the sum of the volumes of the adsorbent components and does not include gaps, voids, pipes, conduits, tubing, plenum spaces, or other volumes along the length of the vapor flow path that do not contain adsorbent material in a plane perpendicular to the vapor flow path. For example, in Figure 1 , the total nominal volume of the canister system is the sum of the volumes of adsorbent volumes 201, 202, 203, and 204 minus any volumes that are void volumes. In Figure 2 , the total nominal volume of the canister system is the sum of the volumes of adsorbent volumes 201, 202, 203, 204, 301, 302, 303, 304, and 305 minus any volumes that are void volumes.

[0232] Determination of Apparent Density of Nominal Volume

[0233] The term "apparent density of nominal volume" as used herein is the mass representative of the adsorbent in the adsorbent volume divided by the nominal volume of the adsorbent, where the length of the volume is defined as the in-situ distance between the vertical plane of the vapor flow path initially in contact with the adsorbent components within the canister system and the vertical plane of the vapor flow path exiting the adsorbent components.

[0234] Non-limiting examples of how to calculate the apparent density of nominal volume for various forms of adsorbents are described herein.

[0235] (A) Granular, pill-shaped or spherical adsorbent having a uniform adsorption capacity over the entire length of the adsorbent component flow path Adsorbent

[0236] The apparent density of nominal volume of particulate adsorbents (such as granular and pelletized adsorbents of the size and shape commonly used for evaporative emission control in fuel systems) can be determined using the standard method ASTM D 2854 (hereinafter referred to as the "standard method"). The apparent density value of the adsorbent volume can be determined using the standard method when the standard method provides the same ratio of mass to nominal volume of the adsorbent bed found in the canister system. The mass of the adsorbent obtained by the standard method is the representative adsorbent used in the incremental adsorption analysis, i.e., depending on the representative material analyzed as the adsorbent sample, equivalently including or excluding inert binders, fillers, and structural components within the adsorbent volume.

[0237] In addition, an alternative apparent density method can be used to determine the nominal bulk apparent density of an adsorbent volume, as defined below. The alternative method can be applied to a nominal adsorbent volume having an apparent density that cannot be equally or properly measured by standard methods. Additionally, due to its generality, the alternative apparent density method can be applied in place of the standard method to particulate adsorbents. The alternative method can be applied to an adsorbent volume that can include particulate adsorbents, non-particulate adsorbents, and any form of adsorbent enhanced by spacers, voids, void additives within a volume or similar sequential adsorbent volumes to achieve a net reduced incremental volume capacity effect.

[0238] In the alternative apparent density method, the apparent density of an adsorbent volume is obtained by dividing the mass of the adsorbent by the volume of the adsorbent, where:

[0239] (1) Measure the dry mass basis of the representative adsorbent in the adsorbent volume. For example, measure the adsorption capacity of a 0.200 g representative sample out of a total adsorbent mass of 25.0 g in the adsorbent volume by the McBain method. The McBain method gives the adsorption value of g butane per g of adsorbent. For the numerator in the apparent density of the adsorbent volume, a mass of 25.0 g is applicable, thus allowing the conversion of the McBain analysis value into a volumetric property of the adsorbent volume; and

[0240] (2) The volume of the adsorbent component in the denominator of the apparent density is defined as the in-situ geometric volume where surface vapor flow paths occur within the canister system. The length of the volume is bounded by a plane perpendicular to the surface vapor flow inlet of the subject adsorbent volume (i.e., the point where there is adsorbent in the vertical plane) and a plane perpendicular to the surface flow at the vapor flow outlet of the adsorbent volume under discussion (i.e., the point where there is no adsorbent in the plane perpendicular to the vapor flow).

[0241] (B) Honeycomb, monolithic or foam adsorbent

[0242] (1) Cylindrical honeycomb adsorbent

[0243] The apparent density of a cylindrical honeycomb adsorbent can be determined according to the procedure of Purification Cellutions, LLC (Waynesboro, Ga.) SOP 500-115. The volume of the adsorbent is the product of the cross-sectional area (A) and the length (h) of the adsorbent. The length (h) of the adsorbent is defined as the distance between the front plane of the adsorbent perpendicular to the vapor or gas flow entering the adsorbent and the rear plane of the adsorbent where the vapor or gas exits the adsorbent. The volume measurement is a measurement of the nominal volume, which is also used to define the bed volume ratio for purging. In the case of a cylindrical honeycomb adsorbent with a circular cross-section, the adsorbent cross-sectional area is πd 2 / 4 is determined, where d is the average diameter measured at four points on each end of the honeycomb. The nominal volume and apparent density are calculated as follows:

[0244] Nominal adsorbent volume = h x A

[0245] Nominal volume apparent density = partial mass / (h x A)

[0246] where "partial mass" is the mass of the adsorbent for a representative adsorbent sample tested for adsorption properties (including typical proportions of inert or adsorptive binders and fillers).

[0247] By way of non-limiting example, Figure 5 illustrates the boundary definition of the nominal volume of a honeycomb adsorbent 109 having a cross-sectional area A. Vapor or gas flows through the honeycomb adsorbent 109 in the direction of D1 to D2. The vapor or gas enters the front plane (F) of the adsorbent 109, flows through the length (h) of the adsorbent 109, and then exits the back plane (B) of the adsorbent 109. The nominal volume of the honeycomb adsorbent 109 is equal to the cross-sectional area A x the length h. Similarly, Figure 6 illustrates the boundary definition of the nominal volume of a foam adsorbent 110.

[0248] (2) Pleated, corrugated, and sheet adsorbents

[0249] For pleated and corrugated adsorbents, the nominal adsorbent volume includes all the void spaces created by the pleats and corrugations. The volume measurement is a measurement of the nominal volume, which is also used to define the bed volume ratio for purging. The nominal volume and apparent density of the adsorbent are calculated as follows:

[0250] Nominal adsorbent volume = h x A

[0251] Nominal volume apparent density = partial mass / (h x A)

[0252] where

[0253] "partial mass" is the mass of the adsorbent for a representative adsorbent sample tested for adsorption properties (including typical proportions of inert or adsorptive binders and fillers),

[0254] h is the length of the adsorbent, defined as the distance between the front plane of the adsorbent perpendicular to the vapor or gas flow into the packing and the back plane of the packing where the vapor or gas exits the adsorbent, and

[0255] A is the cross-sectional area of the adsorbent.

[0256] By way of non-limiting example, Figure 7 illustrates the boundary definition of the volume of a stacked corrugated sheet adsorbent blank 111. It is also within the knowledge of those skilled in the art to form such blanks into extruded honeycombs.

[0257] In the case of a pleated adsorbent, the cross-sectional area of the adsorbent is determined by LxW, where L is the distance in the X direction from one edge of the adsorbent to the opposite edge of the adsorbent, and W is the distance in the Y direction from one edge of the adsorbent to the opposite edge of the adsorbent.

[0258] By way of non-limiting example, Figure 8 shows the boundary definition of the volume of a single pleat or corrugation 112. Figure 9 shows the boundary definition of the volume for a pleated or corrugated sheet 113, where the vapor flow path is provided by the permeability of some form of air flow through the sheet. The face of the sheet is perpendicular to the vapor flow. In contrast, Figure 10 shows the boundary definition of the volume of a pleated or corrugated sheet 114, where its face is angled with respect to the gas flow. Figure 11 shows the boundary definition of the volume of the adsorbent volume 115 of a parallel adsorbent sheet. Figure 12 shows the boundary definition of the volume of an adsorbent sleeve 116.

[0259] Determination of incremental adsorption capacity

[0260] Figure 13 shows a simplified schematic of an apparatus for determining the butane adsorption capacity. This is known in the art as the McBain method. The apparatus 800 includes a sample pan 801 and a spring 802 in a sample tube 803, a roughing vacuum pump 804, a diffusion pump 805, a stopcock valve 806, metal / O-ring vacuum valves 807 to 809, a butane cylinder 810, a pressure readout unit 811, and at least one conduit 812 connecting the components of the apparatus 800.

[0261] A representative adsorbent component sample (“adsorbent sample”) is dried at 110 °C for more than 3 hours before being loaded onto a sample pan 801 attached to a spring 802 within a sample tube 803. Subsequently, the sample tube 803 is installed in the apparatus 800. When the apparent density value is determined to equivalently include the mass of any inert binders, fillers, and structural components in its mass molecules, the adsorbent sample will include a representative amount of any inert binders, fillers, and structural components present in the nominal volume of the adsorbent component. Conversely, when the apparent density value equivalently excludes the mass of the inert binders, fillers, and structural components in its molecules, the adsorbent sample will exclude these inert binders, fillers, and structural components. The general concept is to accurately define the adsorption properties of butane based on volume within the nominal volume.

[0262] A vacuum less than 1 Torr is applied to the sample tube, and the adsorbent sample is heated at 105 °C for 1 hour. The mass of the adsorbent sample is then determined using a cathetometer by the amount of spring extension. Thereafter, the sample tube is immersed in a temperature-controlled water bath at 25 °C. An air pump pumps out the sample tube until the pressure inside the sample tube is 10 -4 Torr. n-Butane is introduced into the sample tube until equilibrium is reached at the selected pressure. The tests are performed on two sets of data for four selected equilibrium pressures, which are obtained at approximately 38 Torr and at approximately 380 Torr, respectively. The concentration of n-butane is based on the equilibrium pressure inside the sample tube. After each test at the selected equilibrium pressure, the mass of the adsorbent sample is measured using a cathetometer based on the amount of spring extension. The increased mass of the adsorbent sample is the amount of n-butane adsorbed by the adsorbent sample. The mass of n-butane adsorbed per mass (gram) of adsorbent sample is determined for each test at different n-butane equilibrium pressures and plotted in a graph against the n-butane concentration (% volume). A 5 volume % n-butane concentration (by volume) at one atmosphere is provided by the equilibrium pressure inside the sample tube at 38 Torr. A 50 volume % n-butane concentration at one atmosphere is provided by the equilibrium pressure inside the sample tube at 380 Torr. Since it is not easy to reach equilibrium exactly at 38 Torr and 380 Torr, the mass of n-butane adsorbed per mass of adsorbent sample at 5 volume % n-butane concentration and at 50 volume % n-butane concentration is interpolated from the graph using the data points collected at approximately the target 38 and 380 Torr pressures.

[0263] Alternatively, Micromeritics (such as Micromeritics ASAP 2020) can be used to determine the incremental butane adsorption capacity to replace the McBain method.

[0264] Determination of the Nominal Incremental Adsorption Capacity

[0265] As used herein, the term "nominal incremental adsorption capacity" refers to the adsorption capacity according to the following equation:

[0266] Nominal incremental adsorption capacity = [Butane adsorbed at 50 volume % - Butane adsorbed at 5 volume %] x Nominal volumetric apparent density x 1000

[0267] Where

[0268] "Butane adsorbed at 50 volume %" is the gram mass of n-butane adsorbed per gram mass of adsorbent sample at 50 volume % butane concentration;

[0269] "Butane adsorbed at 5 volume %" is the gram mass of n-butane adsorbed per gram mass of adsorbent sample at 5 volume % butane concentration; and

[0270] "Nominal volumetric apparent density" is as defined herein.

[0271] Determination of Butane Working Capacity

[0272] The standard method ASTM D5228-16 can be used to determine the butane working capacity (BWC) of the adsorbent volume containing particulate granular and / or pelletized adsorbents. The retention rate (g / dL) is calculated as the difference between the volumetric butane activity (g / dL) [(i.e., the weight-based saturated butane activity (g / 100g) multiplied by the apparent density (g / cc)] and the BWC (g / dL).

[0273] Determination of Nominal Volumetric Butane Working Capacity (BWC)

[0274] The standard method ASTM D5228 can be used to determine the nominal volumetric butane working capacity (BWC) of the adsorbent volume containing particulate granular and / or pelletized adsorbents.

[0275] A modified version of the ASTM D5228 method can be used to determine the nominal volumetric butane working capacity (BWC) of honeycomb, monolith, and / or sheet adsorbent volumes. The modified method can also be used for particulate adsorbents, where the particulate adsorbent includes fillers, voids, structural components, or additives. In addition, the modified method can be used when the particulate adsorbent is not compatible with the standard method ASTM D5228, for example, when a representative adsorbent sample cannot be easily placed as a 16.7 mL fill in the sample tube for testing.

[0276] The modified version of the ASTM D5228 method is as follows. The adsorbent sample is dried at 110 ± 5 °C for at least eight hours and then placed in a desiccator to cool. The dry mass of the adsorbent sample is recorded. Before the adsorbent sample is assembled into the test assembly, the mass of the empty test assembly is determined. Next, the test assembly is installed into a flow device and loaded with n-butane gas at a butane flow rate of 500 ml / min at 25 °C and 1 atmosphere for at least 25 minutes (±0.2 minutes). The test assembly is then removed from the BWC test device. The mass of the test assembly is measured and recorded to the nearest 0.001 gram. This n-butane loading step is repeated for consecutive 5-minute flow intervals until a constant mass is reached. For example, the total butane loading time for a 35 mm diameter 150 mm long honeycomb (Example 27 refill canister adsorbent) is 66 minutes. For cases where the nominal volume can be completely removed and tested, the test assembly can be a container for the honeycomb or monolith section. Alternatively, the nominal volume may need to be a section of the canister system, or a suitable reconfiguration of the nominal volume with contents properly oriented to the gas flow (otherwise encountered in the canister system).

[0277] The test assembly is reinstalled into the test apparatus and purged with air at 2.00 liters per minute at 25 °C and 1 atm for a set selected purge time (±0.2 minutes) according to the formula: Purge time (minutes) = (719 Nominal volume (cc)) / (2000 (cc / minute)).

[0278] The direction of the air purge flow in the BWC test is the same as the direction of the purge flow applied in the canister system. After the purge step, the test assembly is removed from the BWC test apparatus. The mass of the test assembly is measured and recorded to the nearest 0.001 grams within 15 minutes of the completion of the test.

[0279] The nominal volume butane working capacity (BWC) of the adsorbent sample is determined using the following equation:

[0280] Nominal volume BWC (g / dL) = Amount of butane purged (g) / Nominal adsorbent volume (dL).

[0281] Where

[0282] Amount of butane purged = Mass of test assembly after loading - Mass of test assembly after purge.

[0283] As used herein, the term "g total BWC" refers to the g amount of butane purged.

[0284] As used herein, the term "canister approximate total vapor load" refers to the total weight gain of the canister during a two-day diurnal test. It is equal to Day 1 load (g) + Day 2 load (g) - Backpurge (g).

[0285] As used herein, the term "backpurge" refers to the canister weight loss caused by the air flow due to the fuel tank vacuum during the cooling period on Day 1 of the diurnal test.

[0286] Determination of diurnal breathing loss (DBL) emissions

[0287] The evaporative emission control systems of Examples 1 to 118 are assembled with selected amounts and types of adsorbents as shown in Tables 1 to 3 (see Figures 14 to 16 ).

[0288] Each embodiment is uniformly pre-treated (aged) by using repeated cycles of gasoline vapor adsorption with certified TF-1 fuel (9RVP, 10 vol% ethanol) or EPA-certified Tier-3 fuel (9RVP, 10 vol% ethanol) and 300 nominal bed volumes (e.g., 630 L for a 2.1 L main tank) of dry air purge at 22.7 lpm based on the main tank. The gasoline vapor loading rate is 40 g / h and the hydrocarbon composition is 50 vol%, generated by heating two liters of gasoline to approximately 36 C and bubbling air through it at 200 ml / min. Two-liter aliquots of fuel are automatically replaced with fresh gasoline every two hours until breakthrough at 5000 ppm is detected by an FID (flame ionization detector). A minimum of 25 aging cycles are used on unused tanks. The aging cycles are followed by a single butane adsorption / air purge step. This step will load butane at 40 g / h to 5000 ppm breakthrough at an air concentration of 50 vol% at one atmosphere, soak for up to one hour, followed by dry air purge for 21 minutes, where the total purge volume is obtained by selecting a constant air purge rate appropriate for the period. During the previous butane loading and purge steps conducted in a chamber with an ambient temperature of approximately 20 C to 25 C, the tank is then soaked at 20 C for approximately 24 hours with the orifice sealed.

[0289] DBL emissions were then generated by attaching the canister orifice of the example to a fuel tank filled with 40 vol% (based on its rated volume) of CARB LEVIII fuel (7RVP, 10 vol% ethanol) or Phase II (7RVP, 0 vol% ethanol). Prior to attachment, the filled fuel tank was stabilized at 18.3 °C for 24 hours while ventilated. The tank and example were then temperature cycled according to CARB's two-day temperature profile, from 18.3 °C to 40.6 °C over 11 hours each day, then back to 18.3 °C over 13 hours. During the two-day cycle of the 68 L fuel tank and 2.1 L canister described in the present invention, for a net vapor challenge of approximately 61.7 g, the gasoline vapor generation on Day 1 averaged approximately 34 g, the backflush averaged approximately 8.2 g, and the vapor generation on Day 2 averaged approximately 34.3 g. In all cases, vapor generation and backflush were measured by the change in the weight of the example canister during Day 1 heating (Day 1 vapor generation), Day 1 cooling (backflush), and Day 2 heating (Day 2 vapor generation). For fuel systems other than the system described in the present invention, as described above, dedicated or commercial vehicle system fuel tanks and canisters were used to measure vapor generation and backflush. During the 6-hour and 12-hour periods of the heating phase, emission samples were collected from the example orifice into Kynar bags. The Kynar bags were filled with nitrogen to a known total volume based on pressure and then withdrawn into an FID to determine the hydrocarbon concentration. The FID was calibrated with a 5000 ppm butane standard. The mass of the emissions (such as butane) was calculated from the Kynar bag volume, the emission concentration, and assuming an ideal gas. The mass of the emissions at 6 hours and 12 hours each day was added. Following CARB's protocol, the day with the highest total emissions was reported as the "two-day emissions". In all cases, the highest emissions were on Day 2. This procedure is described in its entirety in the SAE technical paper 2001-01-0733 by R.S. Williams and C.R. Clontz titled "Impact and Control of Canister Bleed Emissions" and in Section D.12 of CARB's LEVIII BETP procedure (Evaporative Emission Standards and Test Procedures for Model Year 2001 and Later Model Year Motor Vehicles in California, March 22, 2012).

[0290] For Examples 1 to 16, a 68-liter fuel tank and a 2.1-liter main canister (Tables 1 and 2, main canister type #1) were used as the main canister, which was filled with 2.1 liters of commercially available activated carbon adsorbent pellets ( BAX 1500, Ingevity, North Charleston, South Carolina). Compared to the vent-side particulate adsorbent material described herein, the main canister activated carbon adsorbent pellets typically had a length of about 2 to 2.8 mm and had a high BWC, low flow restriction, and low M / m. The BAX 1500 activated carbon adsorbent is present in two connected volumes of 1.4 liters and 0.7 liters. For Examples 17 to 25 and 99 to 100, a 68-liter fuel tank and a 2.1-liter main tank (Tables 1 and 2, main tank type #2) are used as the main tank, which is filled with 1.8 liters in two connected volumes of 1.4 liters and 0.4 liters of BAX 1500, and filled with 0.3 liters of another commercially available activated carbon adsorbent pellets ( BAX LBE, Ingevity, North Charleston, South Carolina), as shown in Table 1. Similar to BAX 1500, compared with the vent-side particulate adsorbent materials described herein, the BAX LBE activated carbon adsorbent pellets typically have a length of about 2 to 2.8 mm and have a high BWC, low flow restriction, and low M / m. For Examples 26 and 27, a 68-liter fuel tank and a 2.1-liter main tank (Tables 1 and 2, main tank type #3) are used as the main tank, which is filled with 1.8 liters in two connected volumes of 1.4 liters and 0.4 liters of BAX 1500, and filled with 0.3 liters of commercially available activated carbon adsorbent pellets (MPAC I TM , Mahle Corporation) activated carbon adsorbent, as shown in Table 1. For Examples 29 to 62 and 101 to 111, a 60-liter fuel tank and a 2.1-liter main tank (Tables 1 and 2, main tank type #4) are used as the main tank, which is filled with 2.1 liters of commercially available activated carbon adsorbent pellets ( BAX1100, Ingevity, North Charleston, South Carolina) in two connected volumes of 1.4 liters and 0.7 liters. Compared with the vent-side particulate adsorbent materials described herein, the BAX 1100 activated carbon adsorbent pellets typically have a length of about 2 to 2.8 mm and have a high BWC, low flow restriction, and low M / m.

[0291] For Examples 63 to 92, a 60-liter fuel tank and a 2.1-liter main tank (Tables 1 and 2, main tank type #5) are used as the main tank, which is filled with 2.1 liters of BAX 1100LD (low density) activated carbon. For Examples 93 and 94, a 72.7-liter fuel tank and a 2.875-liter main tank (Tables 1 and 2, main tank type #6) are used as the main tank, which is filled with BAX 1100 activated carbon adsorbent in volumes of 2.7 liters, 0.135 liters, and 0.04 liters. For Example 95, a 72-liter fuel tank and a 2.75-liter main tank (Tables 1 and 2, main tank type #7) are used as the main tank, which is filled with 2.3 liters in volumes of 1.8 liters and 0.5 liters BAX 1500 and filled with 0.45 liters of BAX 1100 activated carbon adsorbent as shown in Table 1. For Example 96, a 47-liter fuel tank and a 1.8-liter main tank (Table 1 and Table 2, main tank type #8) are used as the main tank, which is filled with BAX 1100 activated carbon adsorbent. For Examples 97 to 98, a 68-liter fuel tank and a 2.1-liter main tank (Table 1 and Table 2, main tank type #9) are used as the main tank, which is filled with 1.8 liters in two connected volumes of 1.4 liters and 0.4 liters BAX 1500 and filled with 0.3 liters of the low-retention particulate activated carbon adsorbent material described herein.

[0292] The characteristics of each adsorbent are provided in Tables 1 to 3 (see Figures 14 to 16 ). The adsorbent volume of the supplementary tank (if any) is described in Table 2. In addition, Examples 29 to 33, 73, 74, 94, 96 and 106 to 111 include additional adsorbent in the supplementary tank (as described in Table 3, see Figure 15 ), and this additional adsorbent is located downstream of the first adsorbent in the supplementary tank described in Table 1.

[0293] The adsorbent volume filling amounts and dimensions of several exemplary main tanks described in Table 1 are provided below. Adsorbent volumes 201, 202, 203 and 204 refer to the volumes shown in Figure 1 . The label "201 + 202" refers to a single adsorbent volume surrounding the right side of the tank in the illustration of Figure 1 . The label "203 + 204" refers to a single adsorbent volume surrounding the left side of the tank in the illustration of Figure 1 .

[0294] For tank type #1

[0295] The 201 + 202 volume is 1400 cc of BAX 1500, and the vapor flow path length of the 201 + 202 volume is 16.7 cm. The average cross-sectional area is 84 cm2, the equivalent circle diameter is 10.3 cm, and L / D is 1.6.

[0296] The 203 + 204 volume is 700 cc of BAX 1500, and the vapor flow path length of 203 + 204 is 16.6 cm. The average cross-sectional area is 45 cm2, the equivalent circle diameter is 7.6 cm, and L / D is 2.1.

[0297] For tank type #2

[0298] The 201 + 202 volume is 1400 cc of BAX 1500, and the vapor flow path length of the 201 + 202 volume is 16.7 cm. The average cross-sectional area is 84 cm2, the equivalent circular diameter is 10.3 cm, and L / D is 1.6.

[0299] The 203 volume is 400 cc BAX 1500, and the vapor flow path length of the 203 volume is 7.8 cm. The average cross-sectional area is 51 cm2, the equivalent circular diameter is 8.1 cm, and L / D is 1.0.

[0300] The 204 volume is 300 cc BAX LBE, and the vapor flow path length is 7.8 cm. The average cross-sectional area is 38 cm2, the equivalent circular diameter is 7.0 cm, and L / D is 1.1.

[0301] For tank type #3

[0302] The 201 + 202 volume is 1400 cc BAX 1500, and the vapor flow path length of the 201 + 202 volume is 16.7 cm. The average cross-sectional area is 84 cm2, the equivalent circular diameter is 10.3 cm, and L / D is 1.6.

[0303] The 203 volume is 400 cc BAX 1500, and the vapor flow path length of the 203 volume is 7.8 cm. The average cross-sectional area is 51 cm2, the equivalent circular diameter is 8.1 cm, and L / D is 1.0.

[0304] The 204 volume is 300 cc of MPAC 1 TM , and the vapor flow path length is 7.8 cm. The average cross-sectional area is 38 cm2, the equivalent circular diameter is 7.0 cm, and L / D is 1.1.

[0305] For tank type #4

[0306] The 201 + 202 volume is 1400 cc BAX 1100, and the vapor flow path length of the 201 + 202 volume is 16.7 cm. The average cross-sectional area is 84 cm2, the equivalent circular diameter is 10.3 cm, and L / D is 1.6.

[0307] The 203 + 204 volume is 700 cc BAX 1100, and the vapor flow path length of the 203 + 204 is 16.6 cm. The average cross-sectional area is 45 cm2, the equivalent circular diameter is 7.6 cm, and L / D is 2.1.

[0308] For can type #5

[0309] The volume of 201 + 202 is 1400 cc BAX 1100LD, and the vapor flow path length of 201 + 202 is 16.7 cm. The average cross-sectional area is 84 cm2, the equivalent circular diameter is 10.3 cm, and L / D is 1.6.

[0310] The volume of 203 + 204 is 700 cc BAX 1100LD, and the vapor flow path length of 203 + 204 is 16.6 cm. The average cross-sectional area is 45 cm2, the equivalent circular diameter is 7.6 cm, and L / D is 2.1.

[0311] For can type #9

[0312] The volume of 201 + 202 is 1400 cc BAX 1500, and the vapor flow path length of 201 + 202 is 16.7 cm. The average cross-sectional area is 84 cm2, the equivalent circular diameter is 10.3 cm, and L / D is 1.6.

[0313] The volume of 203 is 400 cc BAX 1500, and the vapor flow path length of 203 is 7.8 cm. The average cross-sectional area is 51 cm2, the equivalent circular diameter is 8.1 cm, and L / D is 1.0.

[0314] The volume of 204 is 300 cc of the low-flow restriction pellets of the present invention also found in Example 101, and the vapor flow path length is 7.8 cm. The average cross-sectional area is 38 cm2, the equivalent circular diameter is 7.0 cm, and L / D is 1.1.

[0315] Tables 1 to 3 summarize the conditions of the can systems of Examples 1 to 111 and their measured 2-day DBL emissions. As described above, the California Evaporative Emission Test Procedure (BETP) requires that the 2-day DBL emissions be less than 20 mg. As will be described in the following paragraphs, the evaporative emission control can system of the present disclosure meets the requirement of not exceeding 20 mg for BETP under purge at 150 BV or less.

[0316] As can be seen from the data provided in Table 2 and as described below, the evaporative emission control canister system of the present disclosure has a low two-day DBL, e.g., less than about 50 mg or less than about 20 mg. The adsorbent volume in the examples is described via the fuel vapor flow path (i.e., the sequence from the fuel vapor inlet to the vent). It should be understood that the illustration and description of the adsorbent volume as the "fuel side" and "vent side" are provided for certain aspects and embodiments and do not limit the scope of the present disclosure as understood by those skilled in the art. It is expressly contemplated that the described low retention particulate adsorbent volume can be located at any number of positions in the flow path from the fuel inlet ( Figure 2 104 in Figure 2 to the vent (

[0317] 105 in Figure 2 ). In fact, one or more of the described low retention particulate adsorbent volumes can be placed upstream and / or downstream of: (i) one or more high working capacity adsorbent volumes; (ii) one or more other low capacity adsorbent volumes, e.g., monolith, honeycomb, polymer, or paper sheet; or (iii) any combination thereof. Figure 2 For example, referring to

[0318] , in certain instances, the fuel side adsorbent volume 201 is the first adsorbent volume in the flow path from the fuel vapor inlet 104 to the vent 105. In this case, each additional adsorbent volume in the vapor flow path (i.e., 202, 203, 204, 301, 302, 303, 304, and 305) can be considered a vent side adsorbent volume. In certain embodiments, the first adsorbent volume includes a high working capacity adsorbent material such as particulate. However, the system is not limited thereto. For example, canister systems are also contemplated where the high working capacity adsorbent material is downstream of the first volume or included in multiple adsorbent volumes along the flow path. In certain embodiments, the high working capacity adsorbent volume is upstream of, downstream of, or both, of a lower working capacity adsorbent volume such as the particulate adsorbent volume, monolith, honeycomb, polymer, or paper sheet, or combinations thereof, described herein. Additionally, as those skilled in the art will recognize, the corresponding adsorbent volumes described herein can be located in the same canister or separate canisters or both, and the specific configuration ofNorth Charleston, South Carolina, USA), and the supplemental canister of Example 33 includes the low retention particulate adsorbent described herein, followed by 29x100 HCA. As can be seen from Table 2, Example 33 has a significantly lower two-day DBL (31.1 mg) compared to Comparative Example 32 (50.9 mg). Similarly, relative to Example 29 (44.6 mg; BAX 1100, 5 mm BAX LBE, 29x100 HCA), Example 31 ( BAX1100, low retention particulate adsorbent, 29x100 HCA) has a significant reduction (17.1 mg).

[0319] In addition, the low retention particulate adsorbents of Examples 43, 52, 53, 57, 58, 59, 60, and 62 also show a two-day DBL below 20 mg. Similar to Example 35, BAX 1100 is located on the fuel vapor side in the main canister, and the low retention particulate adsorbent is present downstream (i.e., towards the vent). Compared to comparative examples (e.g., Examples 64, 65, 66, 67, 89, 90, 91, and 68) that received a similar purge treatment (i.e., purge BV of 150 and purge of 315 liters), these examples have a significantly lower two-day DBL, which is below the 20 mg California BETP requirement. Examples including the main canister 5 ( BAX 1100 LD fuel vapor side) and a supplemental canister with a low retention particulate adsorbent (e.g., Examples 80, 85, 79, 88, 86, and 87) also have a two-day DBL below 20 mg.

[0320] Figures 17 to 20 It is demonstrated that the relationship function of the capacity of the first adsorbent in the supplemental canister of Example 31 (i.e., the low retention adsorbent as described herein) with respect to the path length is non-monotonic. That is, surprisingly and unexpectedly, it is observed that at a specific path length, the adsorbent has an unexpected increase in capacity.

[0321] Figure 21Examples illustrate the well-known performance trade-off of using conventional solid particle adsorbents (cylindrical pellets, "filled diamonds") with diameters of 2 to 5 mm in terms of providing reasonable flow restrictions and the desired flexibility in DBL emission performance. These embodiments are applicable to a main tank having one or more vent-side adsorbent volumes (with alternative adsorbent fillings) as described in Tables 2 and 3. When tested under the BETP scenario with a purge of less than 150 bed volumes (BV) based on the total nominal volume of the adsorbent in the system after a 40 g / h butane loading step (see the conventional examples described for the system in Tables 1 to 3), only the carbon honeycomb examples have a reasonable flow restriction of <0.3 kPa for the chamber (i.e., the chamber containing the adsorbent volume, less than the empty container) at 40 standard liters per minute (slpm) for the vent-side volume and BETP test results with less than 50 mg of DBL emissions on the second day. In contrast, conventional pellets less than 3 mm, while being a low-cost solution, have an undesirable trade-off between flow restriction and emission performance. These pellets may match the emission performance but require a geometric ratio of the adsorbent bed with excessive flow restrictions (e.g., a low bed length relative to the diameter), or provide reasonable flow restrictions with a more favorable bed ratio but excessive DBL emissions. Applying a low cross-sectional area to the adsorbent volume or chamber size as taught in U.S. Patent No. 5,957,114 as described above, an elongated chamber with a length-to-diameter ratio L / D greater than 2 is beneficial for the low DBL emission response of conventional particulate adsorbents compared to carbon honeycomb adsorbents of similar size ( Figure 22 ), but those conventional adsorbents have excessive flow restrictions ( Figure 23 ). Significantly, large-diameter solid pellets (Example 1) overcome the flow restriction barrier of the favorable chamber geometry with an L / D greater than 2, but due to the poor purgeability of the large-diameter solid pellets, this seriously impairs the DBL emission performance of the system.

[0322] Figure 24 And Figure 25 show the flow restrictions of conventional pellets and carbon honeycombs at flow rates often mentioned for evaporative emission control canister systems. As described above, canister system manufacturers may initially design the overall adsorbent chamber strategy and then proceed to compare available products, thus comparing and balancing factors such as cost, flow restriction, working capacity performance, and emission control. For Figure 24 And Figure 25In the comparison, a 43 mm diameter × 150 mm long (“43×150”) granular adsorbent bed is a representative example of volumetric filling of a chamber with granular adsorbent that would otherwise contain a 35 mm diameter × 150 mm long carbon honeycomb (“35×150”), i.e., a 35 mm diameter carbon honeycomb plus a 4 mm thick O-ring. The O-ring or other sealing material holds the honeycomb in place and forms a seal between the honeycomb outer skin and the chamber inner wall so that air and vapor flow through the honeycomb pores without bypassing around the perimeter gap around the monolith. In Figure 24 the usual familiar airflows encountered in canister system testing and qualification are highlighted. 15 slpm is the purge flow rate used in the preparation of 150 BV DBL for a 2.1 liter canister system. A purge rate of 22.7 slpm is commonly used in EPAGWC and GWC measurements. In the United States, the maximum fuel flow rate for ORVR is about 10 gallons per minute, which means that the displacement air-vapor flow rate to the canister system is about 40 slpm. As described in the background art, the General Motors specification for the canister system for the maximum flow limit for ORVR is 60 slpm. Figure 25 shows the relationship of those important airflows to the flow limit in terms of the gas velocity in the Figures 21 to 23 vent side volume, expressed in terms of the flow limit per bed or per partial length of the 43 mm diameter bed of the granular example rather than in terms of the chamber limit, as a method for comparing the flow limit properties of materials. Clearly, conventional solid pellets with a typical diameter of 2 to 2.8 mm found in the main canister chamber cannot compare with the carbon honeycomb, making their potential low emission performance impractical for chamber geometries with a required L / D greater than 2.

[0323] To address the limitations exhibited by conventional pellet media for vent side filling, this specification provides a granular adsorbent for at least one volume within a canister system, the granular adsorbent: 1) having a granular shape of a sufficiently large size (e.g., nominal diameter) to obtain low flow limit properties (Pa / cm pressure drop) so as to mitigate the flow limit of a chamber with a favorably elongated geometry, 2) avoiding solid forms such as solid cylinders so as to enhance DBL emission performance, and 3) employing an adsorbent material prepared with appropriately selected fillers, binders, and extrusion aids so as to obtain an M / m ratio for low retention in the range of 150+%, which is contrary to conventional strategies, and obtaining a low flow limit vent side granular adsorbent. Accordingly, this specification unexpectedly and surprisingly provides a canister system that includes a vent side granular adsorbent volume having 150+ M / m properties and having a pressure drop flow limit of <40 Pa / cm at an apparent linear air velocity of 46 cm / s when measured as a 43 mm diameter bed.

[0324] For example, U.S. Patent No. 9,174,195 does not teach the manufacture of low flow restriction adsorbent particulate materials that provide excellent DBL emission control, good strength, and low retention properties. Thus, the present discovery is surprising and unexpected. Additionally, the conventional solid activated carbon pellets 2GK-C7 (Kuraray Chemical Co., Ltd.) with a diameter of 2.6 mm (measured by caliper) described in U.S. Patent Application 2007 / 78056A1 also teach that such performance cannot be obtained from larger pellets with restricted flow.

[0325] 2GK-C7 can be found in the canister systems of 2010 model year Mitsubishi Outlander TM “PZEV” and “Federal” vehicles (i.e., those certified via EPA Tier 2, meeting the 2-day full vehicle test requirement of 500 mg / day) and 2010 model year Suzuki SX-4 vehicles. As obtained from the canister systems manufactured for such vehicles in 2010, 2GK-C7 has a pellet diameter of approximately 2.7 mm, an M / m property of 164%, and a retention of approximately 0.6 g / dL, as determined using the methods described herein. The 2GK-C7 pellets have a strength of 99+ by commercially acceptable methods employed herein. The '195 patent teaches that when preparing large diameter pellets with an M / m increased to levels greater than 150%, the retention gradually stabilizes to approximately 1 g / dL and the strength drops sharply (respectively, Figure 5 and Figure 6 of the '195 patent), thus restricting large diameter pellets with suitable strength and adsorption properties to the space defined by an M / m of less than 150% (and preferably in the range of 65% to 150%).

[0326] In certain embodiments, the present specification provides an evaporative emission canister system including at least one vent side particulate adsorbent volume, wherein the particulate adsorbent material has an M / m greater than 200% and a butane retention of <1 g / dL. In another embodiment, the particulate adsorbent material has an M / m higher than 150% and a butane retention of <0.5 g / dL. Inventive examples of these embodiments are described herein.

[0327] The Pa / cm flow restriction measured using the scheme defined herein is more appropriate than the pellet diameter because complex geometries may impede the accurate measurement of the characteristic diameter, which would otherwise be readily assignable to shapes such as circular cross-section cylinders, triangular solids, square solids, pentagonal solids, hexagonal solids, etc. For the purposes of the physical examples of the present invention, a hollow solid-wall cylinder is employed herein. Alternative shapes for low flow restriction with hollow characteristics can also be utilized (e.g., thin walls, and low diffusion path length resistance between the body phase and the interior of the adsorbent), and these shapes include twisted bands, coiled wires, saddle rings, or hollow shells. These shapes can also include striations, dimples, and perforations to impart better strength and adsorbate washability. Additionally, these more complex shapes can achieve a smaller apparent geometric "diameter" and can accommodate lower flow restrictions compared to what might otherwise be accommodated by a simple cylinder or geometric solid of similar diameter (e.g., an open spring, twisted band, or saddle ring compared to a solid-wall cylinder formed with axially oriented parallel channels).

[0328] Compared to Figure 21 conventional particulate adsorbent examples in Figure 26 shows examples of particulate adsorbents having the characteristics described herein, which are capable of providing low DBL emissions and low flow restriction performance, which is not possible for Figure 21 the conventional materials exemplified in

[0329] Figure 27 shows high-performance inventive embodiments that advantageously have a high chamber L / D greater than 2, which is considered a facilitating factor for low DBL emissions. Figure 28 、 29 and 30 show how the low flow restriction properties of the inventive embodiments enable low flow restriction to be possible for a beneficially high L / D. At an apparent linear air velocity of 46 cm / s, the inventive embodiments are a fraction of the Pa / cm pressure drop flow restriction of conventional 2 to 2.8 mm diameter solid conventional pellets when placed in a similar 43 mm diameter chamber.

[0330] Another surprising aspect of the present invention is that, despite the teachings of the prior art, particularly U.S. Patent 9,174,195, the inventive samples have good strength properties at an M / m ratio of ≥150%. Figure 42 showsFigure 26 and Figure 27 the pellet strength as a function of the M / m property for the particulate adsorbents in the examples of Figure 26 and Figure 27 , where "LFR" represents low flow restriction. For comparison purposes, one measure of acceptable strength in this test is 35. Strength 35 is a property measured for MPAC1 (Kuraray Chemical Co., Ltd.; shown as solid triangle symbols in Figure 42 ), which was obtained from a canister system manufactured for evaporative emission control in vehicles. MPAC1 is a hollow, cylindrical, low flow restriction pellet having a geometry and properties that fall within the ranges taught by U.S. Patent No. 9,174,195, including 66% M / m, and was found to be filled as an adsorbent in the vent side volume of a commercial canister system. For comparison purposes, a second industry-recognized metric is the minimum product strength specification of 40 required by some canister system manufacturers for high working capacity 2 mm BAX 1700 activated carbon pellets. As is evident from Figure 42 the strength of the inventive examples is far higher than the commercial typical value of 35 for low flow restriction pellets and far higher than the minimum specification of 40 for high working capacity pellets. As shown in Figure 43 for this group of inventive canister system examples of Figure 26 and Figure 27 the low flow restriction particulate adsorbents of the present invention are capable of achieving excellent control of DBL emissions while exhibiting good pellet strength and (or despite) having a high M / m property. Although several of the low flow restriction particulate adsorbents of the present invention in the canister system examples have pellet strengths equal to or just below the comparative strength metrics of 35 and 40, the strength of the samples can be further optimized, for example, by modifying the binder formulation while maintaining other desired properties according to the present disclosure.

[0331] The versatility of the inventive examples is demonstrated by their performance under particularly challenging low purge conditions. For example, U.S. Patent No. 9,732,649 teaches that it may be difficult to control DBL emissions at very low levels after a 40 g / h butane loading step under low purge conditions of less than 100 BV (or less than 210 liters of purge), as tested under the BETP test protocol. Under these challenges of low purge, Figure 31 shows examples from Figure 26 filtered to obtain examples where a purge level of <100 BV and <210 liters is applied after a 40 g / h butane loading step, where Figure 26 and Figure 31 all the examples in Figure 32It is shown that when additional vent-side particles are added to the bed (“adsorbent 2”), low system emissions with low flow restrictions are observed. As Figure 33 and Figure 34 shown, the particles of the present invention, as a bed, are contained in the adsorbent 2 chamber, and the adsorbent 2 chamber has an L / D ratio similar to that of a carbon honeycomb. The transfer to a lower L / D value reflects the lack of space consumption and the sealing and retention O-rings with limited cross-sectional area, or similar sealants required for carbon honeycombs in other ways. Importantly, the particle bed of adsorbent 2 in Examples 107 to 110, which results in low blow-by of these canister systems under low purge conditions, has a pellet strength of 51, even though its M / m ratio is as high as 260%.

[0332] For this type 4 main canister, combining the pellet adsorbent of the present invention with a specific 35x100 carbon honeycomb in the subsequent adsorbent volume can achieve very low DBL emissions under low purge conditions. In the case where the 35x100 carbon honeycomb is the final adsorbent volume towards the system vent (the canister system in Example 106), the DBL emission on the second day is 15 mg. However, filling this final chamber with the pellets of the present invention contains 43×100 adsorbent 2 (the canister system in Example 107), and the DBL emission on the second day is even lower, at 12 mg. This result is surprising because conventional strategies believe that the benefit of the monotonous decrease and gradual change of the working capacity towards the system atmospheric vent is most beneficial for DBL emissions, especially for achieving <20 mg under low purge conditions. The present disclosure provides a new option with vent-side particle adsorbent filling to achieve this result, including, for example, having only one adsorbent volume containing carbon honeycomb in the canister system, rather than having carbon honeycomb in multiple volumes, thus having the flexibility to place the particle volume, and the taught particle porosity properties are now shown to have excellent DBL emission performance. For example, the effects and opportunities of the canister system design have the following advantages: the ability to adopt an existing canister system, the canister system design has multiple series-connected adsorbent volumes for accommodating carbon honeycomb on the vent side, and has the flexibility to select a vent-side particle adsorbent solution in one or more of these volumes, without having to redesign and retrofit the system, and still obtain the desired DBL emission performance results within the total system pressure drop limit.

[0333] In certain embodiments, the specification provides an emissions control canister system that, in cases where low DBL emissions results are accompanied by a modest flow restriction in the vent side adsorbent volume, includes a vent side particulate adsorbent having a M / m greater than 150% and a butane retention property of < 0.5 g / dL. For example, a Type 4 main canister (2.1L carbon filled) has a chamber on its vent side that contains a 43 mm diameter x 100 mm long adsorbent bed of low flow restriction hollow pellet particles, and the system is purged with 315 L after a 40 g / h butane loading step, or 139 BV purge for the total adsorbent volume (see Examples 36 - 62). The 2 - day DBL emissions of the base canister is 76 mg (e.g., Example 28; the main canister was tested without the 43x100 external vent side chamber, so for a total adsorbent bed of 2.1L, 315 L purge is 150 BV). The L / D ratio of the adsorbent volume located on the vent side of the auxiliary chamber is 2.56. The flow restriction of the pellet bed in this chamber at 40 lpm flow is 0.22 kPa (10.0 Pa / cm at 46 cm / s apparent linear air velocity), except for the higher 0.26 kPa (13.3 Pa / cm at 46 cm / s apparent linear air velocity) of the Kuraray MPAC1 prior art pellets in Example 47. As Figure 35 and Figure 36 shown, the canister system has multiple inventive embodiments with M / m of 150+% that have emissions of < 20 mg, and some instances are < 10 mg when the butane retention property of the low flow restriction pellets is < 0.5 g / dL. Figure 44 Illustrated are Figure 35 and Figure 36 the pellet strength of the low flow restriction particulate adsorbent of the present invention in the examples of. The low flow restriction particles of the present invention with M / m of 150+% (including M / m properties far higher than 200+%) and a butane retention property below 0.5 g / dL have a pellet strength at 35 and often far above 35.

[0334] Shows another embodiment of a type 5 main canister (2.1L carbon filled) that is equipped with an adsorbent 1 auxiliary chamber on its vent side. The 2-day DBL emissions of the base canister are 93 mg (e.g., Example 63; the main canister was tested without the auxiliary adsorbent 1 chamber, so for a total adsorbent bed of 2.1L, 315 liters of purge is 150 BV). The auxiliary chamber consists of beds of adsorbent 1 of various sizes of conventional pellets, low flow restriction hollow pellet particles, or carbon honeycombs. After a butane loading step of 40 g / h, the canister system is purged with 315L, or 137 to 147 BV of the total nominal adsorbent volume. All examples are purged with the same 315L, but the BV value depends on the size of the vent side chamber outside the main canister, which is different in various examples (see Examples 64 to 69, 76, 79, and 88 to 92). Similar to Figure 35 and Figure 36 the examples in Figure 37 and Figure 38 show that among the tested adsorbents including both particulate and honeycomb forms, the lowest emissions are produced by flow restriction particulate adsorbents having an M / m property greater than 150% and a butane retention rate less than 0.5 g / dL. This material was retested (Examples 86 and 87) because it has surprisingly low outgassing emission performance compared to other tested particulate and honeycomb materials tested in the adsorbent 1 volume. The low flow restriction property of this low flow restriction particulate (10 Pa / cm at an apparent linear air velocity of 46 cm / s in Figure 39 ) results in a relatively low flow restriction for an adsorbent 1 bed with a diameter of 43 mm and a length of 132 mm (0.72 kPa at 40 lpm in Figure 40 ), thus achieving a bed L / D of slightly more than 3 advantageously (see Figure 41 ), which helps enhance outgassing emission control.

[0335] Exemplary embodiment

[0336] In one aspect, the present disclosure provides an evaporative emission control canister system that includes one or more canisters having a plurality of chambers, each chamber defining a volume, the plurality of chambers being in fluid communication to allow fluid or vapor to flow directionally from one chamber to the next, and at least one chamber including at least one particulate adsorbent volume, wherein the at least one particulate adsorbent volume includes a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 nm to 100,000 nm, and a ratio of the volume of macropores to the volume of micropores greater than about 150%, and wherein the particulate adsorbent volume has a flow restriction property of less than 40 Pa / cm under conditions of applying an apparent linear air velocity of 46 cm / s to a 43 mm diameter bed of the particulate adsorbent material.

[0337] In a further aspect, the present disclosure provides an evaporative emission control canister system that includes one or more canisters, the one or more canisters including at least one fuel-side adsorbent volume; and at least one vent-side particulate adsorbent volume, the at least one vent-side particulate adsorbent volume including a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, and a ratio of the volume of macropores to the volume of micropores greater than about 150%, wherein the vent-side adsorbent volume has a flow restriction property of less than 40 Pa / cm pressure drop when an apparent linear air velocity of 46 cm / s is applied to a 43 mm diameter bed of the vent-side particulate adsorbent volume.

[0338] In yet a further aspect, the present disclosure provides an evaporative emission control canister system that includes one or more canisters, the one or more canisters including at least one fuel-side adsorbent volume; and at least one vent-side low-retention particulate adsorbent volume, the at least one vent-side low-retention particulate adsorbent volume including a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, and a ratio of the volume of macropores to the volume of micropores greater than about 150%, wherein the at least one vent-side low-retention particulate adsorbent volume has a butane retention rate of less than 0.5 g / dL.

[0339] In another aspect, the present disclosure provides an evaporative emission control canister system that includes one or more canisters, the one or more canisters including at least one fuel-side adsorbent volume; and at least one vent-side low-retention particulate adsorbent volume, the at least one vent-side low-retention particulate adsorbent volume including a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, a ratio of the volume of the macropores to the volume of the micropores greater than about 200%, and wherein the at least one vent-side particulate adsorbent volume has a butane retention rate of less than 1 g / dL.

[0340] In another aspect, the present disclosure provides an evaporative emission control canister system including: a fuel tank for storing fuel; an engine having an air intake system and adapted to consume fuel; an evaporative emission control canister system including one or more canisters, the one or more canisters including at least one fuel-side adsorbent volume; and at least one vent-side particulate adsorbent volume, the at least one vent-side particulate adsorbent volume including a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, a ratio of the volume of the macropores to the volume of the micropores greater than about 150%, and a retention rate of about 0.5 g / dL or less; a fuel vapor inlet conduit connecting the evaporative emission control canister system to the fuel tank; a fuel vapor purge conduit connecting the evaporative emission control canister system to the air intake system of the engine; and a vent for venting the evaporative emission control canister system and for introducing purge air into the evaporative emission control canister system, wherein the evaporative emission control canister system is defined by: a fuel vapor flow path from the fuel vapor inlet conduit through the plurality of adsorbents to the vent; and an air flow path from the vent through the plurality of adsorbent volumes and the fuel vapor purge outlet.

[0341] In another aspect, the present disclosure provides a method for reducing fuel vapor emissions in an evaporative emission control system, the method including contacting fuel vapor with a plurality of adsorbent volumes, the plurality of adsorbent volumes including at least one fuel-side adsorbent volume; and at least one vent-side particulate adsorbent volume, the at least one vent-side particulate adsorbent volume including a particulate adsorbent having micropores with a diameter of less than about 100 nm, macropores with a diameter of about 100 nm or greater, a ratio of the volume of the macropores to the volume of the micropores greater than about 150%, and a retention rate of about 1.0 g / dL or less.

[0342] In a further aspect, the present disclosure provides an evaporative emission control canister system that includes one or more canisters, the one or more canisters including: at least one fuel side adsorbent volume that includes a particulate adsorbent having micropores with a diameter less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, a ratio of the volume of macropores to the volume of micropores greater than about 150%, and a retention rate less than about 1.0 g / dL; and at least one vent side particulate adsorbent volume that includes a particulate adsorbent having micropores with a diameter less than about 100 nm, macropores with a diameter of about 100 to 100,000 nm, a ratio of the volume of macropores to the volume of micropores greater than about 150%, wherein the at least one vent side particulate adsorbent volume has a butane retention rate less than 1.0 g / dL.

[0343] In any aspect or embodiment described herein, the at least one particulate adsorbent volume, at least one vent side particulate adsorbent volume, or at least one vent side low retention particulate volume has at least one of the following: a flow restriction less than 0.3 kPa at an air flow rate of 40 lpm, a flow restriction property of a pressure drop less than 40 Pa / cm when an apparent linear air velocity of 46 cm / s is applied to a 43 mm diameter bed, a length to diameter ratio of 2 or greater, or a combination thereof.

[0344] In any aspect or embodiment described herein, the at least one particulate adsorbent volume, at least one vent side particulate adsorbent volume, or at least one vent side low retention particulate volume has at least one of the following: (i) a retention rate less than 1.0 g / dL; (ii) a ratio of the volume of macropores to the volume of micropores greater than about 200%; (iii) a length to diameter ratio of 2 or greater; or (iv) a combination thereof.

[0345] In any aspect or embodiment described herein, the evaporative emission control canister system has a two-day diurnal breathing loss (DBL) of no more than 50 mg under a purge of no more than 315 liters applied after a 40 g / h butane loading step, as determined by the 2012 California Bleed Emission Test Procedure (BETP).

[0346] In any aspect or embodiment described herein, the evaporative emission control canister system has a two-day diurnal breathing loss (DBL) of no more than 20 mg under a purge of no more than 210 liters applied after a 40 g / h butane loading step, as determined by the 2012 California Bleed Emission Test Procedure (BETP).

[0347] In any aspect or embodiment described herein, the evaporative emission control canister system has a two-day diurnal breathing loss (DBL) of no more than 50 mg under a purge of no more than 150 bed volumes applied after a 40 g / h butane loading step, as determined by the 2012 California Bleed Emission Test Procedure (BETP).

[0348] In any aspect or embodiment described herein, the evaporative emission control canister system has a two-day diurnal breathing loss (DBL) of no more than 20 mg under a purge of no more than 100 bed volumes applied after a 40 g / h butane loading step, as determined by the 2012 California Bleed Emission Test Procedure (BETP).

[0349] In any aspect or embodiment described herein, the evaporative emission control canister system includes at least one fuel-side adsorbent volume, at least one vent-side adsorbent volume, or both.

[0350] In any aspect or embodiment described herein, the adsorbent volume is located within a single canister or within multiple canisters that are connected to allow sequential contact by fuel vapor.

[0351] In any aspect or embodiment described herein, the at least one particulate adsorbent volume, at least one vent-side particulate adsorbent volume, or at least one vent-side low-retention particulate volume, the at least one vent-side subsequent adsorbent volume, or a combination thereof has a nominal BWC of less than 8 g / dL, a nominal IAC at 25 °C of less than 35 g / L between vapor concentrations of 5 vol% and 50 vol% n-butane, or both.

[0352] In any aspect or embodiment described herein, the at least one vent-side subsequent adsorbent volume is an activated carbon honeycomb.

[0353] In any aspect or embodiment described herein, the at least one particulate adsorbent volume, at least one vent-side particulate adsorbent volume, or at least one vent-side low-retention particulate volume has a retention rate of less than 0.5 g / dL.

[0354] In any aspect or embodiment described herein, the fuel-side adsorbent volume has: a nominal butane working capacity of at least 8 g / dL (e.g., at least 10 g / L); a nominal incremental adsorption capacity (IAC) at 25 °C of at least 35 g / L between vapor concentrations of 5 vol% and 50 vol% n-butane; or both.

[0355] In any aspect or embodiment described herein, the at least one fuel side adsorbent volume, the at least one particulate adsorbent volume, at least one vent side particulate adsorbent volume or at least one vent side low retention particulate volume, the at least one vent side subsequent adsorbent volume, or combinations thereof include an adsorbent material selected from the group consisting of activated carbon, charcoal, zeolite, clay, porous polymer, porous alumina, porous silica, molecular sieve, ball clay, kaolin, titanium dioxide, cerium dioxide, and combinations thereof.

[0356] In any aspect or embodiment described herein, the at least one vent side subsequent adsorbent volume is an activated carbon honeycomb.

[0357] In any aspect or embodiment described herein, the activated carbon is derived from a material that includes a member selected from the group consisting of wood, wood chips, wood flour, cotton linters, peat, coal, coconut, lignite, carbohydrates, petroleum pitch, petroleum coke, coal tar pitch, fruit pits, fruit stones, nut shells, nut kernels, sawdust, palm, vegetables, synthetic polymers, natural polymers, lignocellulosic materials, and combinations thereof.

[0358] In any aspect or embodiment described herein, the form of the adsorbent includes a member selected from the group consisting of granular, pellet, spherical, honeycomb, monolith, pelletized cylinder, uniformly shaped particulate media, non-uniformly shaped particulate media, extruded structured media, wound structured media, folded structured media, pleated structured media, corrugated structured media, cast structured media, bonded structured media, non-woven fabric, woven fabric, sheet, paper, foam, hollow cylinder, star, twisted helix, asterisk, configured strip, and combinations thereof.

[0359] In any aspect or embodiment described herein, the adsorbent volume includes a volume diluent. In any aspect or embodiment described herein, the volume diluent includes a member selected from the group consisting of inert spacer particles, trapped air spaces, foam, fiber, screen, and combinations thereof.

[0360] In any aspect or embodiment described herein, the canister system further includes a heating unit.

[0361] Although several embodiments of the present invention have been shown and described herein, it should be understood that these embodiments are provided by way of example only. Many variations, changes, and substitutions will occur to those skilled in the art without departing from the spirit of the present invention. On the contrary, the present disclosure will cover all modifications, equivalents, and alternative forms falling within the scope of the present disclosure as defined by the appended claims and their legal equivalents. Accordingly, the specification and the appended claims are intended to cover all such variations falling within the spirit and scope of the present invention.

[0362] All references, patents, pending patent applications, and published patents cited throughout this application are hereby expressly incorporated by reference.

[0363] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments described herein. Such equivalents are intended to be encompassed by the following claims. It should be understood that the detailed examples and embodiments described herein are given by way of illustration only and are in no way to be construed as limiting the present invention. Various modifications or variations thereof will be contemplated by those skilled in the art and are included within the spirit and scope of this application and are considered to be within the scope of the following claims. For example, the relative amounts of the ingredients may be varied to optimize the desired effects, other ingredients may be added, and / or one or more of the ingredients may be replaced with similar ingredients. Other advantageous features and functions related to the systems, methods, and processes of the present invention will be apparent from the following claims. In addition, those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described herein. Such equivalents are intended to be encompassed by the following claims.

Claims

1. An evaporative emission control canister system, comprising: at least one particulate adsorbent volume including a particulate adsorbent having micropores with a diameter less than 100 nm, macropores with a diameter of 100 nm to 100,000 nm, and a ratio of the volume of the macropores to the volume of the micropores greater than 160%, and wherein the at least one particulate adsorbent volume has at least one of the following: (i) a nominal butane working capacity of < 8 g / dL, (ii) a butane retention rate of less than 1 g / dL, or (iii) a combination thereof.

2. The evaporative emission control canister system according to claim 1, wherein the at least one particulate adsorbent volume has a flow restriction of less than 0.3 kPa at an air flow rate of 40 lpm, a length-to-diameter ratio of 2 or greater, or both.

3. The evaporative emission control canister system according to claim 1, wherein the at least one particulate adsorbent volume has at least one of the following: (i) a butane retention rate of less than 1.0 g / dL; (ii) a ratio of the volume of the macropores to the volume of the micropores greater than 200%; or (iii) a length-to-diameter ratio of 2 or greater; or (iv) a combination thereof.

4. The evaporative emission control canister system according to claim 1, wherein the at least one particulate adsorbent volume has a nominal incremental adsorption capacity at 25°C of at least 35 g / L between a vapor concentration of 5 vol% and 50 vol% n-butane.

5. The evaporative emission control canister system according to claim 1, wherein the system has a two-day diurnal purge loss of no more than 50 mg under a purge of no more than 315 liters applied after a 40 g / h butane loading step, as determined by the 2012 California evaporative emission test procedure.

6. The evaporative emission control canister system according to claim 5, wherein the two-day diurnal purge loss is no more than 20 mg under a purge of no more than 210 liters applied after a 40 g / h butane loading step, as determined by the 2012 California evaporative emission test procedure.

7. The evaporative emission control canister system according to claim 1, wherein the system has a two-day diurnal purge loss of no more than 50 mg under a purge of no more than 150 bed volumes applied after a 40 g / h butane loading step, as determined by the 2012 California evaporative emission test procedure.

8. The evaporative emission control canister system according to claim 7, wherein the two-day diurnal purge loss is no more than 50 mg under a purge of no more than 100 bed volumes applied after a 40 g / h butane loading step, as determined by the 2012 California evaporative emission test procedure.

9. The evaporative emission control canister system according to any one of claims 1 to 8, wherein the at least one particulate adsorbent volume is located in a single canister or multiple canisters, the multiple canisters being connected to allow sequential contact by fuel vapor.

10. The evaporative emission control canister system according to claim 1, wherein the at least one particulate adsorbent volume has a nominal butane working capacity of less than 8 g / dL; a nominal incremental adsorption capacity at 25 °C of less than 35 g / L between vapor concentrations of 5 vol% and 50 vol% n-butane; or both.

11. The evaporative emission control canister system according to any one of claims 1 to 8, wherein the at least one particulate adsorbent volume comprises an adsorbent material selected from the group consisting of activated carbon, charcoal, clay, porous polymers, porous alumina, porous silica, molecular sieves, kaolin, titanium dioxide, cerium dioxide, and combinations thereof.

12. The evaporative emission control canister system according to claim 11, wherein the activated carbon is derived from a material comprising a member selected from the group consisting of cotton linter, peat, coal, coconut, petroleum pitch, petroleum coke, coal tar pitch, fruit stones, nut shells, sawdust, palm, synthetic polymers, natural polymers, and combinations thereof.

13. The evaporative emission control canister system according to claim 12, wherein the form of the particulate adsorbent is selected from the group consisting of nonwoven fabrics, woven fabrics, sheets, foams, hollow cylinders, stars, twisted spirals, asterisks, configured strips, and combinations thereof.

14. The evaporative emission control canister system according to claim 13, wherein the at least one particulate adsorbent volume comprises a volume diluent.

15. The evaporative emission control canister system according to claim 14, wherein the volume diluent comprises a member selected from the group consisting of foams, fibers, screens, and combinations thereof.

16. The evaporative emission control canister system according to claim 1, further comprising a heating unit.

17. The evaporative emission control canister system according to claim 1, wherein the at least one particulate adsorbent volume has a retention rate of less than 0.5 g / dL.

18. The evaporative emission control canister system according to claim 11, wherein the activated carbon is derived from a material comprising wood.

19. The evaporative emission control canister system according to claim 11, wherein the activated carbon is derived from a material comprising a member selected from the group consisting of wood chips, wood powder, and combinations thereof.

20. The evaporative emission control canister system according to claim 11, wherein the activated carbon is derived from a material comprising carbohydrates.

21. The evaporative emission control canister system according to claim 11, wherein the activated carbon is derived from a material comprising vegetables.

22. The evaporative emission control canister system according to claim 11, wherein the activated carbon is derived from a material comprising lignocellulosic materials.

23. The evaporative emission control canister system according to claim 12, wherein the form of the particulate adsorbent is selected from pellets.

24. The evaporative emission control canister system according to claim 12, wherein the form of the particulate adsorbent is selected from pill-shaped cylinders.

25. The evaporative emission control canister system according to claim 12, wherein the particulate adsorbent is in a form selected from the group consisting of a particulate medium of uniform shape, a particulate medium of non-uniform shape, and combinations thereof.

26. The evaporative emission control canister system according to claim 12, wherein the particulate adsorbent is in a form selected from the group consisting of a structured medium in an extruded form, a structured medium in a wound form, a structured medium in a folded form, a structured medium in a pleated form, a structured medium in a corrugated form, a structured medium in an agglomerated form, and combinations thereof.

27. The evaporative emission control canister system according to claim 14, wherein the volume diluent includes a member selected from the group consisting of inert spacer particles, trapped air spaces, and combinations thereof.

28. An evaporative emission control canister system comprising one or more canisters, the one or more canisters comprising: at least one fuel-side adsorbent volume; and at least one vent-side granular activated carbon adsorbent volume comprising a particulate adsorbent having micropores with a diameter of less than 100 nm, macropores with a diameter of 100 to 100,000 nm, and a ratio of the volume of the macropores to the volume of the micropores of greater than 160%, wherein the at least one vent-side granular activated carbon adsorbent volume has at least one of the following: (i) a butane retention rate of less than 2.0 g / dL, (ii) a nominal butane working capacity of < 8 g / dL, or (iii) a combination of (i) and (ii).

29. The evaporative emission control canister system according to claim 28, wherein the vent-side granular activated carbon adsorbent volume has a butane retention rate of less than 1.0 g / dL.

30. The evaporative emission control canister system according to claim 28, wherein the vent-side granular activated carbon adsorbent volume has a butane retention rate of 0.25 g / dL to 1.0 g / dL.

31. The evaporative emission control canister system according to claim 28, wherein the vent-side granular activated carbon adsorbent volume has a nominal butane working capacity of 1 g / dL to 8 g / dL.

32. The evaporative emission control canister system according to claim 28, wherein the vent-side granular activated carbon adsorbent volume has a nominal butane working capacity of 4 g / dL to 8 g / dL.

33. The evaporative emission control canister system according to claim 28, wherein the vent-side granular activated carbon adsorbent volume further comprises at least one of a porous polymer, porous alumina, clay, porous silica, kaolin, zeolite, metal-organic framework, titanium dioxide, cerium dioxide, and combinations thereof.

34. The evaporative emission control canister system according to claim 28, wherein the activated carbon is derived from at least one material selected from the group consisting of cotton linter, peat, coal, coconut, lignite, petroleum pitch, petroleum coke, coal tar pitch, fruit pits, nut shells, sawdust, palm, synthetic polymers, natural polymers, and combinations thereof.

35. The evaporative emission control canister system according to claim 33, wherein the clay is at least one of zeolite clay, bentonite clay, montmorillonite clay, illite clay, French green clay, pascalite clay, redmond clay, terramin clay, activated clay, bleaching earth clay, Ormalite clay, vitalite clay, rectorite clay, or a combination thereof.

36. The evaporative emission control canister system according to claim 28, wherein the system has a two-day diurnal purge loss of no more than 50 mg under a purge of no more than 315 liters applied after a 40 g / h butane loading step, as determined by the 2012 California evaporative emission test procedure.

37. The evaporative emission control canister system according to claim 28, wherein the activated carbon is derived from a material selected from wood.

38. The evaporative emission control canister system according to claim 28, wherein the activated carbon is derived from at least one material selected from the group consisting of wood chips, wood powder, and combinations thereof.

39. The evaporative emission control canister system according to claim 28, wherein the activated carbon is derived from a material selected from carbohydrates.

40. The evaporative emission control canister system according to claim 28, wherein the activated carbon is derived from a material selected from vegetables.

41. The evaporative emission control canister system according to claim 28, wherein the activated carbon is derived from a material selected from lignocellulosic materials.

42. The evaporative emission control canister system according to claim 28, wherein the activated carbon is derived from a material selected from nut shells.

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