Systems and methods for gasification of feed stock

Abstract

Systems and methods are provided for solid gasification that incorporates at least two reactors. The first reactor may include a fluidized bed gasifier for solids conversion into synthesis gas (i.e., syngas), methane (CH4), tar, and char. The gasified products are passed through at least one cyclone filter. Dipleg effluent including at least a portion of the char is passed into a first zone of the second reactor, which comprises a multi-zone thermal reformer.

Description

SYSTEMS AND METHODS FOR GASIFICATION OF FEED STOCKBACKGROUND OF THE INVENTION

[0001] Solid feed gasification is a subject of increasing importance. Traditional gasification techniques encompass a variety of thermochemical processes aimed at converting carbonaceous feedstocks such as coal, biomass, and municipal solid waste into valuable gaseous products, primarily hydrogen (H2) and carbon monoxide (CO), known as syngas. These techniques have gained significant attention due to their potential to produce clean and versatile fuels while minimizing environmental impact. Gasification methods typically involve subjecting the feedstock to high temperatures and controlled environments, often with limited oxygen or steam, to induce chemical reactions that break down the carbonaceous material.

[0002] Various attempts to improve the efficiency of gasification technologies have been made. For example, United States Patent Number US11,466,223 describes two-stage syngas production using a gasifier reactor vessel and a thermal reformer. Similarly, European Patent Application EP1312662 describes a staged gasification process using a Total Char Combustion and Tar Cracking Chamber (TCC)2positioned between a pyrolysis unit (PYR) and a char reduction reactor (CRC). However, for each of these technologies, the optimal temperatures for syngas conversion vary based on the precursor compounds.SUMMARY OF THE INVENTION

[0003] There is increasing demand for fuel sources, and there is a growing focus regarding sustainability of those fuel sources. Solid feed gasification provides one solution to both of these issues. For example, gasification produces significant amounts of H2 and CO, which is commonly referred to as synthesis gas or syngas. These products can be used to produce clean and versatile fuels while minimizing environmental impact.

[0004] However, gasification commonly produces intermediate products such as char, methane (CH4), and tar. Traditional gasification techniques have at least one drawback. In particular, the temperatures for syngas conversion vary based on the precursor compounds. For example, CH4 and char require high temperatures between l,300°C and l,400°C to convert to syngas while tar is mostly converted at temperatures between l,000°C and l,100°C. Accordingly, traditional gasification / thermal reformers or staged combustion vessels may reduce the overall yield of syngas.

[0005] Embodiments described herein are directed to a multi-zone thermal reformer gasifier systems for solid feed gasification. For example, some aspects are directed to a method for gasification of solids using a multi-zone thermal reformer is described. The method includes exposing a feed stock to a fluidized bed of particles under gasification conditions in a reactor vessel to generate a gasifier effluent includes syngas, methane (CH4), char, and tar. The methods further includes passing at least a portion of the gasifier effluent into a char-separation cyclone that forms an overhead effluent and a dipleg effluent. The overhead effluent may include syngas, tar, and CH4. The dipleg effluent may include char. Additionally, the method includes passing the dipleg effluent into a first zone of a thermal reformer under first thermal reforming conditions to form an intermediate effluent. The first thermal reforming conditions includes a temperature of 1,320 °C to l,700°C. The first zone having a stream of oxygen (O2) injected therein, the stream of O2 comprising 30mol% - 60mol% of a stoichiometric need of O2 for complete combustion of the dipleg effluent. The method further includes converting at least a portion of the dipleg effluent into a partial oxidation product within the first zone and passing the overhead effluent and the partial oxidation product into a second zone of the thermalreformer under second thermal reforming conditions to form a reformer effluent. The second thermal reforming conditions includes a temperature of about 845 °C to l,200°C.

[0006] In another aspect, a multi-zone thermal reformer system is described. For example, the system includes a fluidized bed gasifier includes a gasifier outlet, a solids recycle inlet, a first cyclone having a first entrance, a first overhead outlet, and a first dipleg. The first entrance is in fluid communication with the gasifier outlet and where the first dipleg is in fluid communication with the solids recycle inlet. The system also may also include a second cyclone having a second entrance, a second overhead outlet, and a second dipleg. The second entrance is in fluid communication with the first overhead outlet. The system also includes a thermal reformer that includes a first zone, a first zone inlet, an oxygen inlet, a second zone, and a second zone inlet, where the first zone inlet is in fluid communication with the second dipleg. The second zone inlet is in fluid communication with the second overhead outlet. The first zone can have a cross section smaller than the second zone.BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

[0007] The present systems and methods for solid feed gasification using a multi-zone thermal reformer are described in detail below with reference to the attached drawing figures.

[0008] FIG. 1 depicts an example of a gasifier system including a traditional thermal reformer;

[0009] FIG. 2A depicts an example gasifier system including a multi-zone thermal reformer, in accordance with aspects described herein;

[0010] FIG. 2B depicts an example gasifier system including a multi-vessel thermal reformer, in accordance with aspects described herein;

[0011] FIG. 3 depicts an example method for multi-zone or multi-vessel thermal reformer gasification of solid feeds, in accordance with aspects described herein;

[0012] FIG. 4A depicts an example process for multi-zone or multi-vessel thermal reformer gasification of solid feeds including methanol synthesis, in accordance with aspects described herein;

[0013] FIG. 4B depicts an example process for multi-zone or multi-vessel thermal reformer gasification of solid feeds including Fischer-Tropsch synthesis, in accordance with aspects described herein; and

[0014] FIG. 4C depicts an example process for multi-zone or multi-vessel thermal reformer gasification of solid feeds including pressure swing absorption, in accordance with aspects described herein.DETAILED DESCRIPTION OF THE INVENTION

[0015] In various aspects, systems and methods are provided for gasification of solid feeds while modifying and / or improving the product slate from gasification. The modified and / or improved products from gasification are achieved in part by having an integrated gasification process with at least three stages and / or temperature zones. A first stage I temperature zone performs a gasification process, where particulate solid matter, such as one or more types of biomass, is exposed to gasification conditions. This produces gasification products, including hydrogen and carbon monoxide (synthesis gas), methane (and / or other small hydrocarbons), tar, and particles of char. The char is then separated from the remaining products. The char is then passed into a second stage / temperature zone that operates under partial oxidation conditions with an exit temperature of 1300°C or higher. This allows for conversion the char under partial oxidation conditions into additional synthesis gas. The remaining separated products (methane, tar, synthesis gas)are passed into a third stage / temperature zone, along with the products from the second stage / temperature zone. The third stage / temperature zone is another partial oxidation zone operated at a lower outlet temperature of 1200°C or less. This is sufficient for formation of additional synthesis gas from the tar, while reducing or minimizing loss of synthesis gas product to combustion. The products from the second stage / temperature zone provide at least a portion of the heat for operation of the third stage, so that rather than needing to recover heat from a stream at 1300 °C or higher, the output flow from the second stage is used for direct heating of the third stage. Optionally, methane can also be added as part of the input flow(s) for the second stage / temperature zone for formation of additional synthesis gas. One possible source of this methane is recycle of methane from the gasifier products. Such recycle can be performed at any convenient location, and could be recycle from a downstream process that makes use of the synthesis gas as an input flow.

[0016] Gasification is a thermochemical process that converts carbonaceous materials into gaseous products by reacting them with a controlled amount of oxygen and / or steam. For gasification of biomass, solid waste, or other carbon-containing solid fractions, an initial gasification stage allows for conversion of an input flow of solid particles into hydrogen, carbon oxides, methane, a tar product, and a char or carbon residue product.

[0017] One difficulty with gasification is that the methane, tar, and char products represent a substantial amount of the carbon present in the input flow to the gasifier, possibly corresponding to 25 wt% or more of the products. Conventionally, in order to improve the yield of synthesis gas products (H2 and CO), the total effluent from gasification can be exposed to partial oxidation conditions. Due to the nature of the methane and char products from gasification, the partial oxidation reactor is operated with an exit temperature of greater than 1300°C. This facilitates conversion of the char andmethane, but also results in consumption of additional synthesis gas as fuel during the partial oxidation reaction. Additionally, this also results in an effluent at a temperature of greater than 1300°C. This limits the initial options for heat recovery, as radiant coolers or direct quenching coolers are needed to handle cooling of streams in that temperature range. Thus, an undesirable percentage of the heat from the effluent stream is lost as waste heat, due to inefficiencies in heat recovery from streams at temperatures above 1200°C.

[0018] In various aspects, the above difficulties can be at least partially overcome by using multiple stages / temperature zones to perform the partial oxidation process on the gasification products. Instead of passing the entire gasification effluent into the partial oxidation process, one or more initial separations are used to separate the solid char from the remaining fluid phase portions of the effluent. The solid char, along with a fluidizing gas, is then passed into a higher temperature stage or zone of the partial oxidation process.

[0019] The heat in the partial oxidation process is provided by reaction of oxygen with the char to form carbon oxides. By separating the char from the rest of the effluent, the heat used to raise the temperature in the first partial oxidation zone is produced by the partial oxidation of char, while reducing or minimizing combustion of synthesis gas. The partial oxidation results in formation of additional H2, H2O, CO, and CO2 (in other words, additional synthesis gas components).

[0020] The products from the first partial oxidation reaction exit from the first stage or zone at a temperature of greater than 1300°C. Instead of trying to recover heat from the first partial oxidation products by heat exchange to raise steam, the first partial oxidation products are passed into a second partial oxidation stage, where the first partial oxidation products provide at least a portion of the heat for operating the second partial oxidation stage or zone. The remaining portion of the gasifier effluent is passed into this secondpartial oxidation stage or zone. This zone operates a temperature of 850°C to 1200°C, which is suitable for conversion of the tar. In some embodiments, a stream of O2 is injected into the second partial oxidation stage or zone. This may be preferable depending on the solid feed input, the operating temperature of the second partial oxidation stage or zone, rate that the first partial oxidation products mix into the second partial oxidation stage or zone, or any combination thereof. By performing the prior separation, the amount of the synthesis gas, methane, and tar that is consumed in the second partial oxidation stage is reduced or minimized, as a substantial portion of the heat for the second partial oxidation is provided by the combustion / partial combustion of the char in the first partial oxidation stage.

[0021] It is noted that the based on the separation, the methane from the gasifier is not directly passed into the first partial oxidation stage, and the temperature in the second partial oxidation stage is too low for substantial conversion of the methane. Depending on the use for the synthesis gas, the methane can be handled in a variety of manners. For example, if the synthesis gas generated by the integrated process is further separated to recover just hydrogen, the methane can form part of a residual fuel gas from the hydrogen recovery process. Alternatively, if the synthesis gas is used as an input flow to a process such as methanol formation or Fischer-Tropsch synthesis, the nature of such processes effectively results in “separation” of the methane. This is because the methane is largely non-reactive under methanol synthesis or Fischer-Tropsch conditions, but these processes form products with boiling points facilitate separation from the methane. Any methane recovered from a process such as methanol synthesis or Fischer-Tropsch synthesis can be returned to the integrated gasification system. For example, the methane can be used as a fluidizing gas or lift gas to assist with transport of char into the first partial oxidation stage.In this way, the methane is eventually returned to the first partial oxidation stage, to allow for conversion of the methane into hydrogen and carbon oxides for production of additional synthesis gas. Additionally or alternately, other sources of methane and / or light hydrocarbons can be passed into the first partial oxidation stage.DEFINITIONS

[0022] In this discussion, the reactors and other process elements shown in the figures can be described as being in direct or indirect fluid communication. Direct fluid communication corresponds to process elements that are in fluid communication without an intervening process element. Indirect fluid communication corresponds to process elements that are in fluid communication via an intervening process element.

[0023] As used herein the term “partial oxidation” and the variants thereof refer to a thermochemical process wherein sub-stoichiometric oxidation of a carbonaceous material takes place to exothermically produce carbon monoxide, carbon dioxide, and optionally water vapor and hydrogen. The reactions are exothermic with reaction temperatures in a range between 500°C and l,700°C. A stoichiometric amount of oxygen is defined as the amount of oxygen required for complete combustion of the carbon and hydrogen in a feed to form CO2 and H2O. A sub-stoichiometric amount of oxygen refers to having less than the amount of oxygen that would be needed for complete combustion.

[0024] As used herein the term “carbon oxides” refers to carbon monoxide (CO), carbon dioxide (CO2), or the combination thereof.

[0025] Processing of Gasifier Effluent

[0026] In various aspects, the effluent from a gasifier can be processed using a partial oxidation process that includes multiple zones and / or stages. For convenience, the description of partial oxidation will be provided primarily by referring to having multiplezones of partial oxidation, such as two or more reaction zones within a single reactor. However, unless otherwise specified, it is understood that the partial oxidation description provided herein equally applies to configurations where multiple partial oxidation stages are present, such as having a first partial oxidation reactor and a second partial oxidation reactor.

[0027] As a preliminary step, the gasifier effluent is separated into one or more fluid streams that include methane, tar, and synthesis gas (H2, carbon oxides, water), and a one or more additional streams that include particles of char. Depending on the nature of the feed, the char separated from the gasifier effluent corresponds to 5.0 wt% to 25 wt% of the weight of the solid particle input to the gasifier, or 5.0 wt% to 20 wt%, or 5.0 wt% to 15 wt%, or 10 wt% to 25 wt%, or 10 wt% to 20 wt%. The one or more fluid streams correspond to the balance of the gasifier effluent. It is noted that some solids may be entrained with the one or more fluid streams, and that some fluids may be entrained with the solid particles.

[0028] The preliminary separation can be performed in any convenient manner. For example, one or more cyclones can be used to separate solid char particles from the remaining fluid phase portions of the effluent. Optionally, if multiple cyclones are used, two or more separate cyclone dipleg outputs can be formed. The first cyclone (or cyclones) can separate out the largest char particles, and return such particles to the gasifier for further reaction. A second cyclone (or cyclones) then separates smaller char particles from the fluid phase portions of the effluent. In this type of multiple cyclone configuration, roughly 5.0 wt% to 30 wt% of the char is returned to the reactor by the first cyclone(s), while 70 wt% to 95 wt% of the char is separated out by the second cyclone(s) to form the char portion of the input flow to the first partial oxidation stage.

[0029] After separation, the separated char is passed into the first partial oxidation zone (and / or stage). The first partial oxidation can be performed in a zone of a single reactor vessel, or the first partial oxidation can be performed in a first reactor / stage of a multireactor I multi-stage partial oxidation configuration, or a combination thereof. The specific configuration for the first partial oxidation zone is not critical, so long as char is exposed to the conditions in the first partial oxidation zone while reducing or minimizing the amount of tar that is also exposed to the conditions in the first partial oxidation zone.

[0030] In order to pass the char into the first partial oxidation zone (and / or stage), a fluidizing gas can be used to enable transport of the char particles into the first partial oxidation zone. Several options are available for the fluidizing gas. One option is to use nitrogen, which will dilute the resulting products from the first partial oxidation zone, but otherwise will not have a substantial impact on the reactions. Another option is to use a fluidizing gas that can assist with forming additional synthesis gas under the conditions in the first partial oxidation zone. In some aspects, any convenient type of gas flow that includes methane can be used as the fluidizing gas. Natural gas is an example of an external methane source that can be used for the fluidizing gas. Another option is to use methane recycled from a downstream process.

[0031] Oxygen is also introduced into the first partial oxidation zone (and / or stage). In a partial oxidation reaction, the goal is to provide a limited amount of oxygen relative to complete stoichiometric combustion. This allows at least a portion of the partial oxidation products to correspond to H2 and CO, as opposed to only forming the typical combustion products of H2O and CO2. In various aspects, the oxygen introduced into the first partial oxidation zone corresponds to 30 mol% to 70 mol% of the stoichiometric need for combustion of the carbon and hydrogen in the feed to the first partial oxidation zone, or30 mol% to 60 mol%, or 30 mol% to 50 mol%, or 40 mol% to 70 mol%, or 40 mol% to 60 mol%, or 50 mol% to 70 mol%. It is noted that the stoichiometric need is based on any carbon and hydrogen present in the feed that is not already in the form of CO2 and H2O. Thus, the stoichiometric need includes the stoichiometric need for the char particles; any hydrocarbon-like compounds in the fluidizing gas (such as methane or natural gas); any H2 and / or CO that is entrained with the char particles; and any tar that remains entrained with the char particles. The amount of oxygen introduced into the first partial oxidation zone or stage can be determined in part based on the amount of oxygen needed to maintain a target temperature for the first partial oxidation reaction. Additionally or alternately, the amount of oxygen can be sufficient so that 90 wt% or more of the solid char particles introduced into the first partial oxidation zone or stage are converted into gas phase products, or 95 wt% or more, or 98 wt% or more, such as up to 100 wt% (substantially complete conversion of solid particles to gas phase products).

[0032] In various aspects, the first partial oxidation zone (and / or stage) is maintained at a temperature ranging from 1300°C to 1700°C, or 1300°C to 1500°C, or 1350°C to 1700°C, or 135O°C to 1500°C, or 1400°C to 1700°C. The temperature of the first partial oxidation zone or stage is characterized at the exit from the zone or stage. Thus, still higher temperatures may be present within the zone or stage. Additionally or alternately, the first partial oxidation zone or stage is maintained at a pressure ranging from 0 kPa-g to 200 kPa-g (~0 psig to 30 psig), or 0 kPa-g to 100 kPa-g. In some aspects the oxygen-containing gas can be air. In other aspects, the oxygen-containing gas can have a low nitrogen content, such as oxygen from an air separation unit or another oxygen stream including 95 vol % or more of oxygen, or 98 vol % or more. More generally, a stream containing 10 vol% to100 vol% oxygen, or 10 vol% to 50 vol%, or 25 vol% to 100 vol%, or 50 vol% to 100vol%, or 95 vol% to 100 vol%< or 98 vol% to 100 vol%, is passed into the first partial oxidation zone. In aspects where the oxygen-containing gas has a low nitrogen content, a separate diluent stream, such as a recycled CO2, can also be passed into the first partial oxidation stage, to provide sufficient gas flow within the first partial oxidation stage for heat transfer.

[0033] The products from the first partial oxidation zone are then passed into the second partial oxidation zone. The products from the first partial oxidation zone are at a temperature of 1300°C or higher, and therefore can provide heat for the second partial oxidation zone. In various aspects, the second partial oxidation zone (and / or stage) is maintained at a temperature ranging from 1300°C to 1700°C, or 1300°C to 1500°C, or 1350°C to 1700°C, or 135O°C to 1500°C, or 1400°C to 1700°C. The temperature of the first partial oxidation zone or stage is characterized at the exit from the zone or stage. Thus, still higher temperatures may be present within the zone or stage. Additionally or alternately, the first partial oxidation zone or stage is maintained at a pressure ranging from 0 kPa-g to 200 kPa-g ('0 psig to 30 psig), or 0 kPa-g to 100 kPa-g. In some aspects the oxygen-containing gas can be air. In other aspects, the oxygen-containing gas can have a low nitrogen content, such as oxygen from an air separation unit or another oxygen stream including 95 vol % or more of oxygen, or 98 vol % or more. More generally, a stream containing 10 vol% to 100 vol% oxygen, or 10 vol% to 50 vol%, or 25 vol% to 100 vol%, or 50 vol% to 100 vol%, or 95 vol% to 100 vol%< or 98 vol% to 100 vol%, is passed into the first partial oxidation zone. In aspects where the oxygen-containing gas has a low nitrogen content, a separate diluent stream, such as a recycled CO2, can also be passed into the first partial oxidation stage, to provide sufficient gas flow within the first partial oxidation stage for heat transfer.

[0034] In some embodiments, remnant oxygen from the first partial oxidation zone is sufficient to facilitate the partial oxidation reactions in the second partial oxidation zone. In other embodiments, a stream of oxygen is injected into the second partial oxidation zone. The stream of oxygen facilitates maintaining a partially oxidative environment.

[0035] Feedstock and Gasifier Operation

[0036] In various aspects, the feed to the gasifier can be particles of a carbon-containing solid. While biomass is a preferred option, coal and / or other solid carbonaceous fuels can also be used.

[0037] In aspects where at least a portion of the feed corresponds to biomass and / or compounds derived from biomass, the biomass can correspond to 5.0 wt% to 100 wt% of the feed, or 10 wt % to 100 wt %, or 20 wt % to 100 wt %, or 40 wt % to 100 wt %, or 50 wt % to 100 wt %, or 5.0 wt % to 95 wt %, or 10 wt % to 95 wt %, or 20 wt % to 95 wt %, or 40 wt % to 95 wt %, or 50 wt % to 95 wt %, or 50 wt % to 75 wt %, or 5.0 wt % to 75 wt %, or 10 wt % to 75 wt %, or 20 wt % to 75 wt %, or 5.0 wt % to 49 wt %, or 10 wt % to 49 wt %, or 20 wt % to 49 wt %.

[0038] The biomass used for a feed can be any convenient type of biomass. Some forms of biomass can include direct forms of biomass, such as algae biomass and plant biomass. Examples of suitable biomass sources can include woody biomass and switchgrass. Other forms of biomass may correspond to waste products, such as food waste, animal waste, paper, and / or other waste products originally formed from biomass materials. In this discussion, municipal solid waste is included within the definition of biomass, even though a portion of the solids in municipal solid waste may not strictly correspond to solids derived from biomass.

[0039] In some aspects, having a small particle size can facilitate transport of the solids into the reactor. Smaller particle size can potentially also contribute to achieving a desired level of conversion of the biomass. Thus, one or more optional physical processing steps can be used to prepare solid forms of biomass for conversion. To prepare solids for gasification, the solids can be crushed, chopped, ground, or otherwise physically processed to reduce the median particle size to 3.0 cm or less, or 2.5 cm or less, or 2.0 cm or less, or 1.0 cm or less, such as down to 0.01 cm or possibly still smaller. For determining a median particle size, the particle size is defined as the diameter of the smallest bounding sphere that contains the particle.

[0040] The gasification zone is typically maintained at a high temperature ranging from 750°C to l,000°C ('1,382°F to l,830°F) and a pressure ranging from 0 kPag to 4000 kPag ('0 psig to 580 psig), preferably from 200 kPag to 400 kPag (~30 psig to 60 psig). Steam and an oxygen-containing gas are introduced to provide fluidization and an oxygen source for gasification. In some aspects the oxygen-containing gas can be air. In other aspects, the oxygen-containing gas can have a low nitrogen content, such as oxygen from an air separation unit or another oxygen stream including 95 vol % or more of oxygen, or 98 vol % or more. More generally, a stream containing 10 vol% to 100 vol% oxygen, or 10 vol% to 50 vol%, or 25 vol% to 100 vol%, or 50 vol% to 100 vol%, or 95 vol% to 100 vol%< or 98 vol% to 100 vol%, is passed into the gasifier for reaction with the solid particles. In aspects where the oxygen-containing gas has a low nitrogen content, a separate diluent stream, such as a recycled CO2, can also be passed into the gasifier.Configuration Examples

[0041] FIG. 1 shows an example of a traditional gasification configuration, to illustrate the comparison with the gasification plus multi-stage partial oxidation configurationsdescribed herein. In the example shown in FIG. 1, a traditional gasifier system 100 includes a fluidized bed reactor vessel 102, a cyclone 104, reactor vessel 110, and cooling device 112. In general, a fluidized bed such as reactor vessel 102 is a vertical vessel equipped with an inlet for introducing particles of a solid fuel and a distribution plate to evenly distribute gas flow. Once the solid fuel is introduced into the fluidized bed reactor, a fluidization process is initiated by introducing a flow of gas, typically air or steam, from the bottom of the reactor. The upward flow of gas suspends the solid particles, forming a fluidized bed with characteristics akin to a boiling liquid.

[0042] Traditionally, the fluidized gas suspension flows from the reactor vessel 102 into a cyclone 104. The cyclone 104 separator facilitates the separation of relatively heavy solid particles from the gas stream, ensuring that only the gaseous products proceed to the subsequent processing stages. The separated solid particles, consisting primarily of ash and unreacted char, are collected via dipleg 108 and discharged for appropriate handling or, as depicted, reintroduced into reactor vessel 102 for further gasification. In contrast, the gasified materials (e.g., syngas, tar, methane, and char) flow through an overhead outlet 106 into a thermal reformer such as reactor vessel 110. Traditional gasifier systems 100 include a single zone reactor vessel 110 that is held at a reaction temperature. Commonly the reaction temperature for the single zone reactor vessel 110 is 1350°C. The reactor vessel 110 serves as a key component in the gasification process, providing a controlled environment for further transformation of the syngas into energy products. For example, within the reactor vessel 110, the syngas undergoes catalytic reactions, facilitated by high temperatures and the presence of catalyst materials, to enhance the conversion of carbon monoxide (CO) and hydrogen (H2) into desired end products such as methane (CH4), hydrogen-rich gases, or liquid fuels.

[0043] As mentioned, traditional gasification techniques have at least one draw back. In particular, the temperatures for syngas conversion vary based on the precursor compounds. For example, CH4 and char require high temperatures between l,300°C and l,400°C to convert to syngas. However, tar could be mostly converted at temperatures between l,000°C and l,100°C. The reliance on a traditional reactor vessel 110 may reduce the overall yield of syngas.

[0044] With general reference to FIG. 2A and FIG. 2B, example multi-zone thermal reformer gasifier systems for solid feed gasification are depicted, in accordance to aspects described herein. Generally, the gasifier system stages the reaction temperature conditions to facilitate conversion of gasified products with a thermal reformer while maintaining relatively low effluent temperatures at the outlets. The gasifier can be a fluid or fixed bed reactor vessel to facilitate utilization of traditional reactor vessel equipment. In embodiments, solid fuel is fed into the fluidized bed reactor vessel. The fluidization process begins, initiating a sequence of dynamic interactions crucial for efficient gasification. A controlled flow of gas, typically air or steam, is introduced from the bottom of the reactor, establishing an upward current that imparts kinetic energy to the solid particles. As the gas velocity surpasses the terminal velocity of the particles, they form a fluidized bed characterized by vigorous mixing and high heat transfer rates.

[0045] The gasified fuel is directed from the fluidized bed reactor through at least one cyclone separator. The cyclone separator(s) at least partially facilitates the separation of entrained solid particles from the gas stream, ensuring that only the gaseous products proceed to the subsequent processing stages. The separated solid particles, consisting primarily of ash and unreacted char, are collected and discharged for appropriate handling or recirculated into the gasifier, minimizing fouling and maintaining the integrity ofdownstream equipment. Following cyclone separation, the gasified fuel, now purified and predominantly composed of syngas, tar, char, and methane, is channeled into a thermal reformer. In contrast to traditional single zone thermal reformers, the multi-zone thermal reformer facilitates at least two thermally regulated zones for transformation of the syngas, tar, char, and methane into energy products. The effluent of the thermal reformer is cooled via a cooling device.

[0046] Continuing with general reference to FIG. 2A and FIG. 2B, the system for gasification of biosolids described herein includes a fluidized bed gasifier with an indirect fluid connection to a muli-zone thermal reformer or a multi-vessel thermal reformer. Each zone or vessel of the thermal reformer maintaining different thermal reforming conditions. A first zone or reactor vessel maintaining a thermal reforming condition having an outlet temperature of l,320°C to l,700°C and having a stream of O2 comprising 30mol% - 60mol% of a stoichiometric need of O2 for complete combustion of the dipleg effluent. The second zone or vessel maintaining a thermal reforming having an outlet temperature of about 845°C to l,200°C. In some embodiments, the first zone or vessel has a cross section smaller than the second zone or vessel. As depicted, the first zone or vessel may be positioned above the second zone or vessel along a vertical axis.

[0047] With specific reference to FIG. 2A an example multi-zone thermal reformer gasifier system 200a is depicted. Gasifier system 200a includes fluidized bed gasifier 202, ash-separation cyclone 204, Char-separation cyclone 210, and thermal reformer 216. Fluidized bed gasifier 202 includes at least one of a feed stock inlet 226, lift inlet 224, outlet 228, and ignition device 230. Feed stock inlet 226 facilitates introduction of feed stock (e.g., municipal solid waste, biomass, or coal) into the internal cavity of the fluidizedbed gasifier 202. The feed stock inlet 226 is generally configured to minimize pressure differentials and facilitate efficient flow distribution within the fluidized bed gasifier 202.

[0048] Lift inlet 224 facilitates introduction of a gasifier lift gas into the internal cavity of the fluidized bed gasifier 202. Similar to traditional gasifier system 100 of FIG. 1, the controlled flow of the gasifier lift gas (e.g., air or steam) introduced from the bottom of the fluidized bed gasifier 202 at lift inlet 224 generally facilitates creation of an upward current that imparts kinetic energy to solid particles of feed stock. Outlet 228 generally includes an orifice that allows waste products (e.g., ash) to exit the fluidized bed gasifier 202 for disposal or down stream usage.

[0049] In some embodiments, the fluidized bed gasifier 202 also includes a distribution plate. The distribution plate is generally situated at the base of the fluidized bed gasifier 202. The distribution plate comprises a perforated structure or an array of nozzles to ensure uniform distribution of the fluidization medium (typically air or steam) across the bed. In some embodiments, the distribution plate may promote even fluidization and enhances gas-solid interactions.

[0050] Ash-separation cyclone 204, at least partially, facilitates the separation of entrapped solid particles from the gas stream for subsequent processing stages. To facilitate this separation, ash-separation cyclone 204 includes at least one inlet, a first overhead outlet 206, and a first dipleg 208. For example, the ash-separation cyclone 204 may be in direct or indirect fluid communication with fluidized bed gasifier 202 such that at least a portion of the gasified feed stock effluent passes through an overhead outlet of fluidized bed gasifier 202 into an inlet of ash-separation cyclone 204. Centrifugal separation of the gasified feed stock separates the comparatively dense solid particles from the gas stream. At least a portion of the solid particles flow through the first dipleg 208and exit the ash-separation cyclone 204. As depicted in FIG. 2A, in some embodiments, first dipleg 208 is in direct or indirect fluid communication with fluidized bed gasifier 202. In contrast to the solid particles, the gas stream flows through first overhead outlet 206.

[0051] The Char-separation cyclone 210 includes at least one inlet, a first second overhead outlet 212, and a second dipleg 214. The inlet may be in direct or indirect fluid communication with ash-separation cyclone 204. The second overhead outlet 212 is in direct or indirect fluid communication with a first zone 218 of thermal reformer 216. In some embodiments, the second dipleg 214 of Char-separation cyclone 210 is in direct or indirect fluid communication with a first zone 218 of a thermal reformer 216. Accordingly, some embodiments for char- separation cyclone 210 facilitate the centrifugal separation of the in-flowing gas stream from ash-separation cyclone 204. For example, the inlet may be in direct or indirect fluid communication with first overhead outlet 206 of ash-separation cyclone 204 such that at least a portion of the gasified effluent passes through first overhead outlet 206 into the inner portion of Char-separation cyclone 210. The inner portion of Char-separation cyclone 210 is configured to facilitate the separation of at least a portion of an inflowing gas stream into at least two sub-portions. For example, Charseparation cyclone 210 may include a lower conical portion that narrows into the second dipleg 214 and an internal tubular portion that is coupled with the second overhead outlet 212. As the gasified effluent from first overhead outlet 206 enters the Char-separation cyclone 210 through the inlet, it is subjected to a swirling motion within the Charseparation cyclone 210. Due to the centrifugal force generated by this swirling motion, comparatively dense portion of the gasified mixture (e.g., char) are forced outward toward the cyclone wall and into second dipleg 214. The comparatively lighter gasified mixture (e.g., syngas, tar, and CH4) continues upward toward the second overhead outlet 212. Saiddifferently, Char-separation cyclone 210 receives at least a portion of the gasifier effluent from ash-separation cyclone 204 and facilitates forming an overhead effluent and a dipleg effluent. The overhead effluent can include syngas, tar, and CH4. The dipleg effluent can include char.

[0052] Thermal reformer 216 generally facilitates conversion of gasified materials, such as syngas, tar, methane, and char, into valuable hydrogen-rich gases or liquid fuels. Within a thermal reformer, gasified materials are subjected to high temperatures ranging from 700°C to l,800°C in the presence of steam. The thermal reformer 216 is typically constructed with refractory materials capable of withstanding extreme conditions. As the gasified materials interact with oxygen and steam within the reformer, they undergo a series of endothermic reactions. In some embodiments, steam reforming reactions occur, wherein hydrocarbons present in the gasified materials react with steam to produce hydrogen (H2), carbon monoxide (CO), and carbon dioxide (CO2). In some embodiments, a water-gas shift reaction takes place, converting carbon monoxide into additional hydrogen and carbon dioxide. These reforming reactions may, in some embodiments, be catalyzed by metal-based catalysts, such as nickel or cobalt, enhancing reaction rates and efficiency.

[0053] Thermal reformer 216 includes first zone 218. The first zone 218 generally facilitates partial oxidation of char. Accordingly, the first zone 218 is held in a first thermal reforming condition comprising an outlet 238 temperature in an inclusive range of l,320°C to l,700°C. In a preferred embodiment the outlet 238 temperature is around l,500°C.The first zone 218 includes a first zone inlet 232 connected to the dipleg of the char-separation cyclone to facilitate direct or indirect fluid communication between first zone 218 and thechar-separation cyclone dipleg effluent. In some embodiments, as depicted in FIG. 2A, the inlet 232 is connected to second dipleg 214.

[0054] The first zone 218 also includes O2 inlet 234 that facilitates injection of a stream of O2 into first zone 218. In some embodiments, the stream of O2 comprises 30mol% - 60mol% of the stoichiometric need for complete combustion of the char-separation cyclone dipleg effluent (e.g., effluent from second dipleg 214). Said differently, the stream of O2 facilitates converting at least a portion of the dipleg effluent into a partial oxidation product within the first zone 218.

[0055] Additionally, in some embodiments, the connection between the dipleg of the char-separation cyclone (e.g., second dipleg 214) and inlet 232 includes a pressure reduction device. The pressure reduction device may comprise a venturi flow restrictor, a high temperature gate valve, or any other pressure reduction device that facilitates balancing pressure.

[0056] Additionally, in some embodiments, the connection between the dipleg of the char-separation cyclone (e.g., second dipleg 214) and inlet 232 includes an inlet for lift gas. This lift gas inlet facilitates injection of a lift gas into the stream of char. In some embodiments, the lift gas includes a stream of steam, CO, CO2, or a combination thereof. In some embodiments, the lift gas includes a stream methane. The source of methane may be a downstream reactor vessel, an external source of methane, or a combination thereof. Said differently, some embodiments of the described gasifier system incorporate a stream of methane as a lift gas for char prior to injection into first zone 218.

[0057] Thermal reformer 216 also includes second zone 220. The second zone 220 generally facilitates mixing of effluent from first zone 218 and the overhead effluent from the second overhead outlet 212. Additionally, second zone 220 facilitates thermalconversion of at least a portion of tar. Accordingly, the second zone 220 is held in a second thermal reforming condition comprising an outlet 240 temperature in an inclusive range of 845 °C to l,200°C. In a preferred embodiment the outlet 240 temperature is around l,050°C. The second zone 220 includes a second zone inlet 236 that is coupled to the overhead outlet of the char-separation cyclone (e.g., second overhead outlet 212) to facilitate direct or indirect fluid communication between second zone 220 and the charseparation cyclone overhead effluent.

[0058] Additionally, in some embodiments, the second zone 220 includes an O2 inlet that provides a supplemental stream of O2. The supplemental stream of O2 may facilitate tuning the oxidative conditions within second zone 220 for optimal tar conversion.

[0059] As depicted in FIG. 2A, some embodiments of thermal reformer 216 include a single reactor vessel with two joined zones. Alternatively, as depicted in FIG. 2B, some embodiments of thermal reformer 216 include at least two reactor vessels, each housing a zone, that are in direct or indirect fluid communication. Said differently, thermal reformer 216 may be a single multi-zoned reactor vessel, or may be a multi-vessel reactor. Accordingly, as depicted in FIG. 2A, the top portion of the inner cavity of second zone 220 may be directly coupled to the inner cavity outlet 238 of first zone 218. Alternatively, as depicted in FIG. 2B, the top portion of the inner cavity of second zone 220 includes an inlet 242 coupled to outlet 238 that facilitates fluid communication from the vessel containing the first zone 218 and the vessel containing the second zone 220.

[0060] Cooling device 222 generally facilitates dissipation of thermal energy stored by the gasified effluent flowing out of thermal reformer 216 via outlet 240. Accordingly, an inlet of cooling device 222 is coupled to outlet 240 to facilitate fluid communication between thermal reformer 216 and cooling device 222. In some embodiments, the coolingdevice 222 is a convection cooler, partial quench cooler, and a full water quench cooler. Advantageously, the temperature of the reformer effluent at outlet 240 is 845 °C to l,200°C which may eliminate the need for a radiant cooler. Accordingly, in some aspects and in contrast to traditional gasifier systems (e.g., traditional gasifier system 100 of FIG. 1), cooling device 222 does not include a radiant cooler.

[0061] Although not depicted, the gasifier system (e.g., gasifier system 200a or gasifier system 200b) may include one or more methane recycling devices downstream of cooling device 222. For example, the gasifier system may include one or more synthesis gas conversion stages. The synthesis gas conversion stages may include at least one of a methanol synthesis catalyst or Fischer-Tropsch synthesis catalyst. For another example, the gasifier system may include pressure swing absorption vessel to separate methane from hydrogen and other reformer effluents. In some embodiments, isolated methane may be passed back into the gasifier system as a lift gas via injection between the dipleg of the char-separation cyclone (e.g., second dipleg 214) and inlet 232. Alternatively, the gasifier system may include a power generator. The power generator may include a natural gas combined cycle (NGCC) generator.

[0062] Turning to FIG. 3, a method 300 for the gasification of solid feed stock is depicted, in accordance to aspects described herein. Some embodiments of method 300 may be facilitated by gasifier system 200a of FIG. 2A or gasifier system 200b of FIG. 2B. Generally, method 300 includes exposing a feed stock to a fluidized bed of particles under gasification conditions in a reactor vessel. The feed stock is gasified to generate a gasifier effluent including syngas, methane (CH4), char, and tar. The gasifier effluent may be passed into a char-separation cyclone that forms an overhead effluent and a dipleg effluent.The dipleg effluent is passed into a first zone of a thermal reformer to form an intermediateeffluent which reacts with a stream of O2 to form a partially oxidized product. The overhead effluent is passed into a second zone of the thermal reformer and mixed with the partially oxidized product. The mixture reacts in the second zone to form a reformer effluent which is passed into a cooling device.

[0063] In particular, method 300, at block 302, includes exposing a feed stock to a fluidized bed of particles under gasification conditions in a reactor vessel to generate a gasifier effluent comprising syngas, methane (CH4), char, and tar. In some aspects, method 300 may be facilitated in part by a fluidized bed gasifier, such as fluidized bed gasifier 202. For example, feed stock may be introduced via a feed stock inlet 226 into the inner cavity of fluidized bed gasifier 202. The feed stock may undergo devolatilization, where volatile components, including hydrocarbons and tars, are released as gases. Partial oxidation reactions may also take place as the released volatiles react with a controlled amount of oxygen or steam to produce additional CO and H2, along with small amounts of carbon dioxide (CO2) and methane (CH4). Additionally, tar formation may occur as a byproduct of incomplete combustion or cracking reactions. Methane may also form through secondary reactions between hydrogen and carbon. Finally, any remaining carbonaceous residue (e.g. char) may react with steam through steam reforming reactions, generating additional H2 and CO. The gasified products may flow through an overhead outlet of fluidized bed gasifier 202 as gasifier effluent. In some embodiments, the gasifier effluent may have a temperature around 850°C.

[0064] Method 300, at block 304, includes passing the gasifier effluent into a charseparation cyclone that forms an overhead effluent and a dipleg effluent. In some aspects, method 300 may be facilitated in part by a cyclone filter, such as Char-separation cyclone210. For example, the gasifier effluent from block 302 may flow from fluidized bedgasifier 202 into an inlet of Char- separation cyclone 210. As the hot gasifier effluent containing the mixture of syngas, tar, methane, and char enters the Char-separation cyclone 210, it is directed tangentially into a cylindrical chamber. This generates a rotation of the gasifier effluent, which induces centrifugal forces that cause the heavier particles, such as char, to migrate towards the outer wall of the cyclone chamber due to their higher inertia. At least a portion of the char travels into the second dipleg 214. The lighter gases, including syngas, tar, and methane, remain closer to the center and continue through the second overhead outlet 212.

[0065] In some embodiments, block 304 also includes passing the gasifier effluent into an ash-separation cyclone prior to the char-separation cyclone. The inclusion of an ashseparation cyclone may be incorporated to reduce the amount of undesired solids that flow into a downstream thermal reformer. In some aspects, method 300 may be facilitated in part by a cyclone filter, such as ash-separation cyclone 204. For example, the gasifier effluent from block 302 may flow from fluidized bed gasifier 202 into an inlet of ashseparation cyclone 204. The gasifier effluent is separated from at least a portion of any residual solid particulates (e.g., ash) from the syngas, tar, methane, and char. Ash flows through the first dipleg 208 and may be disposed or returned to fluidized bed gasifier 202. In such an embodiment, the syngas, tar, methane, and char flows through the first overhead outlet 206 into Char-separation cyclone 210.

[0066] Method 300, at block 306, includes passing the char-separation cyclone dipleg effluent into a first zone of a thermal reformer under a first thermal reforming condition to form an intermediate effluent. In some aspects, method 300 may be facilitated in part by a char-separation cyclone (e.g., Char-separation cyclone 210) and a multi-zone thermal reformer (e.g., thermal reformer 216). For example, as at least a portion of the char travelsthrough the second dipleg 214 it may be passed via on or more conduits through an inlet232 into a first zone 218 of thermal reformer 216. The first thermal reforming conditions include maintaining an outlet temperature of l,320°C to l,700°C. Additionally, in some embodiments, a stream of O2 comprising 30mol% - 60mol% of the stoichiometric need of O2 for complete combustion of the dipleg effluent is injected into the first zone 218 via O2 inlet 234. Said another way, the stream of O2 is injected to support partial oxidative reactions.

[0067] Method 300, at block 308, includes converting at least a portion of the dipleg effluent into a partial oxidation product within the first zone. As mentioned in relation to block 306, the presence of oxygen in limited quantities ensures that only partial oxidation reactions occur. This prevents complete combustion of the char and promotes the desired gasification reactions. As the char reacts with the oxygen the reaction produces partial oxidation products including carbon monoxide (CO) and hydrogen (H2). These gasification reactions are typically exothermic, releasing heat energy that further sustains the process resulting in an outlet temperature in the range of l,320°C to l,700°C. Additionally, the limited presence of oxygen may help suppress the formation of carbon dioxide (CO2) and methane (CH4), which are typically formed under more oxidative conditions or lower temperatures.

[0068] Method 300, at block 310, includes passing the overhead effluent and the partial oxidation product into a second zone of the multi-zone thermal reformer to form a reformer effluent. The overhead effluent and the partial oxidation product may The second zone may be under second thermal reforming conditions comprising an outlet temperature of about 845°C to l,200°C. Some embodiments of method 300 may be facilitated in part by second zone 220 of thermal reformer 216. In some embodiments, method 300 includes atemperature differential between effluent exiting zone one of the thermal reformer and effluent exiting zone two of the thermal reformer is at least 120°C. In another embodiment, the temperature differential between effluent exiting zone one of the thermal reformer and effluent exiting zone two of the thermal reformer is at least 450°C. In another embodiment, the temperature differential between effluent exiting zone one of the thermal reformer and effluent exiting zone two of the thermal reformer is at least 475°C.

[0069] Some embodiments of method 300 also include passing at least a portion of the reforming effluent into a cooling device. This may be facilitated in part by cooling device 222 in fluid communication with outlet 240 of thermal reformer 216. In some embodiments, the cooling device comprises at least one of a convection cooler, partial quench cooler, and a full water quench cooler. Advantageously, the comparatively lower outlet temperature of the reformer effluent allows for less complex cooling devices to be incorporated into the cooling processes. For example, traditional gasifier systems (e.g., traditional gasifier system 100 of FIG. 1) commonly have outlet temperatures of at least l,300°C and include a radiant cooler. However, in at least one embodiment of method 300, the cooling device does not include a radiant cooler.

[0070] Additionally, some embodiments of method 300 include passing a cooled effluent from the cooling device into a synthesis process and separating the CH4 from the effluent from the synthesis process. The synthesis process may include one or more of methanol synthesis and Fischer-Tropsch synthesis. Additionally, or alternatively, method 300 may include recycling at least a portion of methane included in the cooled effluent as a lift gas. For example, some embodiments of method 300 include passing a cooled effluent from the cooling device into a pressure swing absorption vessel. The pressure swing absorption vessel may at least partially facilitate isolating the methane. The methane lift gas mayfacilitate conveying the second dipleg 214 effluent to the first zone 218 of thermal reformer 216. In such an embodiment, the methane lift gas can undergo pyrolysis within the first zone. In some embodiments, the conditions of the first zone may convert at least 70% CH4 into H2 and carbon oxides. In some embodiments, the conditions of the first zone may convert at least 80% CH4 into H2 and carbon oxides. In some embodiments, the conditions of the first zone converts at least 85% CH4 into H2 and carbon oxides. In some embodiments, the conditions of the first zone converts at least 90% CH4 into H2 and carbon oxides. In some embodiments, the conditions of the first zone converts at least 95% CH4 into H2 and carbon oxides. In some embodiments, the conditions of the first zone converts at least 96% CH4 into H2 and carbon oxides. In some embodiments, the conditions of the first zone converts at least 97% CH4 into H2 and carbon oxides. In some embodiments, the conditions of the first zone converts at least 98% CH4 into H2 and carbon oxides. In some embodiments, the conditions of the first zone converts at least 99% CH4 into H2 and carbon oxides.Integration Example - Methanol Synthesis

[0071] In some aspects, an integrated gasifier and partial oxidation system as described herein can be further integrated with one or more downstream processes. One option is to use the output flow from the integrated gasifier and partial oxidation system as an input for a synthesis process, such as methanol synthesis or Fischer-Tropsch synthesis.

[0072] FIG. 4A shows a process flow 400a of integration of a gasifier I partial oxidation system with a methanol synthesis process. Process flow 400a includes gasifier 402, separator(s) 404, first POx zone 406, second POx zone 408, and methanol synthesis stage 410. In FIG. 4A, the output stream 418 from the second POx zone 408 includes synthesis gas (H2, CO, CO2, H2O) formed from both the gasifier (e.g., gasifier 402) and the partialoxidation zones (e.g., first POx zone 406 and second POx zone 408). The output stream418 also includes methane that did not undergo reaction under the lower severity conditions in the second partial oxidation zone.

[0073] The output stream 418 is passed into methanol synthesis stage 410. Any convenient type of liquid phase and / or gas phase methanol reactor can be used. Optionally, a plurality of methanol reactors in series can be used, to account for the relatively low conversion rate for some types of methanol synthesis reactors. The reactor can operate at conventional methanol synthesis conditions, such as a pressure from 200 psia to 2000 psia, and may require that output stream 455 is compressed. The reaction temperature is typically from 150°C to 400°C.

[0074] For a conventional methanol synthesis process, a typical composition for the input flow would be 50-80% H2, 10-30% CO, 5-20% CO2, and 3-5% methane and other inerts. It is noted that the composition of output stream 418 can more broadly range from 20-50% H2O, 10-40% H2, 10-40% CO, 5-30% CO2, 0-20% CH4, and 0-15% N2. It is noted that for methanol synthesis, there is a preference for having a “syngas number” (SN) of 1.4 to 2.6, preferably 1.8 to 2.2. The “syngas number” is a molar ratio of components in the synthesis gas, which is defined as:

[0075] SN=(H2- CO2) / (CO + CO2).

[0076] Depending on the aspect, the SN for the output stream 455 can range from 2.0 to 4.0. In some embodiments, the SN for the output stream 455 can range from 2.0 to 3.5. In some embodiments, the SN for the output stream 455 can range from 2.0 to 3.0. In some embodiments, the SN for the output stream 455 can range from 2.0 to 2.6. In some embodiments, the SN for the output stream 455 can range from 2.5 to 4.0. In someembodiments, the SN for the output stream 455 can range from 3.0 to 4.0. In some embodiments, the SN for the output stream 455 can range from 3.5 to 4.0.

[0077] Within a methanol synthesis process, methane (and / or other small hydrocarbons) are relatively inert under the reaction conditions. As a result, any methane introduced into the methanol synthesis reactor does not impact the SN of the input flow. Instead, the main impact of methanol present in the input flow is to require a somewhat larger reactor vessel to accommodate the increased gas volume.

[0078] After methanol synthesis, the methanol (liquid phase) product can be separated from the unreacted gas phase components. This can potentially include some synthesis gas. This stream of unreacted gas phase components can be returned to the first partial oxidation zone for formation of additional synthesis gas.Integration Example - Fischer-Tropsch Synthesis

[0079] Another option is to use the output flow from the integrated gasifier and partial oxidation system as an input for a Fischer-Tropsch synthesis.

[0080] FIG. 4B shows an example of integration of a gasifier / partial oxidation system with a Fischer-Tropsch synthesis process. Process flow 400b includes gasifier 402, separator(s) 404, first POx zone 406, second POx zone 408, and Fischer-Tropsch synthesis stage 412. In FIG. 4B, the output stream 416 from the second partial oxidation zone includes synthesis gas (Hi, CO, CO2, H2O) formed from both the gasifier and the partial oxidation zones. The output stream 416 also includes methane that did not undergo reaction under the lower severity conditions in the second partial oxidation zone.

[0081] The output stream 416 is passed into Fischer-Tropsch synthesis stage 412. Any convenient type of Fischer-Tropsch reactor can be used. The most common catalysts utilized can typically include iron-based catalysts (for so-called high-temperature-Fischer-Tropsch synthesis) and cobalt-based catalysts (for so-called low temperature-Fischer- Tropsch synthesis). Iron-based catalysts, along with other related catalysts, can also be referred to as shifting catalysts, as the water-gas shift reaction can tend to be readily equilibrated on these catalysts. Cobalt-containing catalysts and other related catalysts can be referred to as non-shifting, as they do not appear to substantially perform and / or catalyze the water-gas shift equilibration reaction at standard operating conditions.

[0082] Examples of suitable Fischer-Tropsch catalysts can generally include a supported or unsupported Group VIII, non-noble metal e.g., Fe, Ni, Ru, and / or Co, with or without a promoter e.g., ruthenium, rhenium, and / or zirconium. These Fischer-Tropsch processes can typically include fixed bed, fluid bed, and / or slurry hydrocarbon synthesis. In some aspects, a preferred Fischer-Tropsch process can be one that utilizes a non-shifting catalyst, such as based on cobalt and / or ruthenium, preferably comprising at least cobalt, and preferably a promoted cobalt, with the promoter comprising zirconium and / or rhenium, preferably being rhenium, although other promoter metals may also be used. The activities of these catalysts can be enhanced by the addition, optionally as part of a catalyst support, of a variety of metals, including copper, cerium, rhenium, manganese, platinum, iridium, rhodium, molybdenum, tungsten, ruthenium or zirconium.

[0083] The reactor can operate at conventional Fischer-Tropsch synthesis conditions. Such conditions can include a temperature range of 150°C to 320°C and pressures ranging from 100 kPaa to 10 MPaa. Modifying the reaction conditions within the Fischer-Tropsch process can provide control over the yield and / or composition of the reaction products, including at least some control of the chain length of the reaction products. Typical reaction products can include alkanes (primary reaction product), as well as one or more of oxygenates, olefins, other hydrocarbonaceous compounds similar to hydrocarbons butwhich may contain one or more heteroatoms different from carbon and hydrogen, and various additional reaction by-products and / or unreacted feed components. These additional reaction products and feed components can include H2O, unreacted syngas (CO and / or H2), and CO2, among other things. Any methane included in the feed to the Fischer- Tropsch process can also be passed into process effluent as an unreacted feed component. These additional reaction products and unreacted feed components can form a tail gas that can be separated from the primary reaction products of the Fischer-Tropsch process, which are typically liquids. This tail gas can be returned to the first partial oxidation zone for further production of synthesis gas.Integration Example - Hydrogen Production

[0084] Still another option is to recover the hydrogen from the output flow from the integrated gasifier and partial oxidation system. Any convenient type of separation stage for separating a high purity hydrogen stream from a stream containing carbon oxides and methane can be used. Examples of commercial separation methods for recovering hydrogen from a stream containing carbon oxides and / or methane are swing adsorption separations and membrane separations. For example, FIG. 4C shows an example of integration of a gasifier / partial oxidation system with a pressure reduction device. Process flow 400c includes gasifier 402, separator(s) 404, first POx zone 406, second POx zone 408, and pressure swing absorption stage 414. In a membrane separation system, the hydrogen will typically correspond to a permeate. The retentate can include the methane and carbon oxides, and the retentate can be recycled back to the first partial oxidation zone. For a swing adsorption process, either the hydrogen or the carbon oxides plus methane can be the selectively adsorbed component. Again, after the separation, the methane plus carbon oxides can be recycled back to the first partial oxidation zone. It isnoted that an additional separation to separate out CO2 from methane may be needed, so that carbon oxides do not accumulate in the system.

[0085] Certain features have been described using a set of numerical upper limits and a set of numerical lower limits. It should be appreciated that ranges from any lower limit to any upper limit are contemplated unless otherwise indicated. Certain lower limits, upper limits and ranges appear in one or more claims below. All numerical values take into account experimental error and variations that would be expected by a person having ordinary skill in the art.

[0086] The foregoing description of the disclosure illustrates and describes the present methodologies. Additionally, the disclosure shows and describes exemplary methods, but it is to be understood that various other combinations, modifications, and environments may be employed and the present methods are capable of changes or modifications within the scope of the concept as expressed herein, commensurate with the above teachings and / or the skill or knowledge of the relevant art.

[0087] While specific elements and steps are discussed in connection to one another, it is understood that any element and / or steps provided herein is contemplated as being combinable with any other elements and / or steps regardless of explicit provision of the same while still being within the scope provided herein. Since many possible embodiments may be made of the disclosure without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

[0088] As used herein and in connection with the claims listed hereinafter, the terminology "any of clauses" or similar variations of said terminology is intended to be interpreted such that features of claims / clauses may be combined in any combination. Forexample, an exemplary clause 4 may indicate the method / apparatus of any of clauses 1 through 3, which is intended to be interpreted such that features of clause 1 and clause 4 may be combined, elements of clause 2 and clause 4 may be combined, elements of clause 3 and 4 may be combined, elements of clauses 1, 2, and 4 may be combined, elements of clauses 2, 3, and 4 may be combined, elements of clauses 1, 2, 3, and 4 may be combined, and / or other variations. Further, the terminology "any of clauses" or similar variations of said terminology is intended to include "any one of clauses" or other variations of such terminology, as indicated by some of the examples provided above.

[0089] Clause 1. A method for gasification of solids comprising: exposing a feed stock to a fluidized bed of particles under gasification conditions in a reactor vessel to generate a gasifier effluent comprising syngas, methane (CH4), char, and tar; passing at least a portion of the gasifier effluent into a char-separation cyclone that forms an overhead effluent and a dipleg effluent, the overhead effluent including syngas, tar, and CH4, and the dipleg effluent including char; passing the dipleg effluent into a first zone of a thermal reformer under first thermal reforming conditions to form an intermediate effluent, the first zone having a stream of oxygen (02) injected therein, the first thermal reforming conditions comprising a temperature of l,320oC to l,700oC, the stream of 02 comprising 30mol% - 60mol% of a stoichiometric need of 02 for complete combustion of the dipleg effluent; converting at least a portion of the dipleg effluent into a partial oxidation product within the first zone; and passing the overhead effluent and the partial oxidation product into a second zone of the thermal reformer under second thermal reforming conditions to form a reformer effluent, the second thermal reforming conditions comprising a temperature of about 845°C to l,200°C.

[0090] Clause 2. The method for gasification of clause 1, wherein passing at least a portion of the gasifier effluent into the char-separation cyclone comprises: passing a first portion of the gasifier effluent into a first cyclone to form a first cyclone effluent; and passing at least a portion of the first cyclone effluent into the char-separation cyclone.

[0091] Clause 3. The method for gasification of clauses 1 or 2, wherein the overhead effluent comprises syngas, tar, and CH4.

[0092] Clause 4. The method for gasification of any of clauses 1 through 3, wherein the method further comprises: injecting a second stream of O2 into the second zone, the second stream of O2 comprising 30mol% - 60mol% of the stream of O2 injected into the first zone of the thermal reformer.

[0093] Clause 5. The method for gasification of any of clauses 1 through 4, wherein a temperature differential between effluent exiting the first zone of the thermal reformer and effluent exiting the second zone of the thermal reformer is at least 120°C.

[0094] Clause 6. The method for gasification of clause 5, wherein the temperature differential is at least 450°C.

[0095] Clause 7. The method for gasification of clause 6, wherein the temperature differential is at least 475°C

[0096] Clause 8. The method for gasification of any of clauses 1 through 7, wherein the at least a portion of the dipleg effluent is conveyed to the first zone using a lift gas.

[0097] Clause 9. The method for gasification of clause 8, wherein the lift gas comprises steam, CO, or CO2-

[0098] Clause 10. The method for gasification of clauses 8 or 9, wherein the lift gas comprises CH4, at least a portion of the CH4 in the lift gas comprising CH4 recycled from the reforming effluent.

[0099] Clause 11. The method for gasification of any of clauses 1 through 10, wherein the method further comprises: passing at least a portion of the reforming effluent into a cooling device without passing the at least a portion of the reforming effluent into a radiant cooler system, wherein the cooling device comprises at least one of a radiant cooler, partial quench cooler, and a full water quench cooler.

[0100] Clause 12. The method for gasification of clauses 10 or 11, wherein the at least a portion of the CH4 in the lift gas that is recycled from the effluent of the thermal reformer.

[0101] Clause 13. The method for gasification of clause 12, wherein the first zone converts at least 70% CH4 into H2 and C.

[0102] Clause 14. The method for gasification of clause 13, wherein the first zone converts at least 80% CH4 into H2 and C.

[0103] Clause 15. The method for gasification of clause 14, wherein the first zone converts at least 85% CH4 into H2 and C.

[0104] Clause 16. The method for gasification of clause 15, wherein the first zone converts at least 90% CH4 into H2 and C.

[0105] Clause 17. The method for gasification of clause 16, wherein the first zone converts at least 95% CH4 into H2 and C.

[0106] Clause 18. The method for gasification of clause 17, wherein the first zone converts at least 96% CH4 into H2 and C.

[0107] Clause 19. The method for gasification of clause 18, wherein the first zone converts at least 97% CH4 into H2 and C.

[0108] Clause 20. The method for gasification of clause 19, wherein the first zone converts at least 98% CH4 into H2 and C.

[0109] Clause 21. The method for gasification of clause 20, wherein the first zone converts at least 99% CH4 into H2 and C.

[0110] Clause 22. The method for gasification of any of clauses 11 through 21, wherein capturing CH4 from the cooling device comprises: passing a cooled effluent from the cooling device into a synthesis process and separating the CH4 from the effluent from the synthesis process, wherein the synthesis process comprises more of methanol synthesis, and Fischer-Tropsch synthesis.

[0111] Clause 23. The method for gasification of any of clauses 11 through 22, wherein capturing the CH4 from the cooling device comprises: passing a cooled effluent from the cooling device into a pressure swing absorption vessel.

[0112] Clause 24. The method for gasification of any of clauses 11 through 23, wherein the method further comprises generating power from at least a portion of the CH4, syngas, or a combination thereof.

[0113] Clause 25. The method for gasification of any of clauses 1 through 24, further comprising: passing the effluent collected from the first outlet of the second cyclone dipleg through a pressure reduction device prior to passage into a first zone of a thermal reformer.

[0114] Clause 26. The method for gasification of clause 25, wherein the pressure reduction device includes at least one of a static venturi type flow restriction and a high temperature gate value.

[0115] Clause 27. The method for gasification of any of clauses 1 through 26, wherein the method further comprises injecting a stream of renewable natural gas (RNG) into the first zone.

[0116] Clause 28. The method for gasification of any of clauses 1 through 27, wherein the first zone and the second zone are in one vessel of the thermal reformer, with the first zone has a cross sectional area smaller than the second zone.

[0117] Clause 29. A system for gasification of biosolids, the system comprising: a fluidized bed gasifier comprising a gasifier outlet, a solids recycle inlet; a first cyclone having a first entrance, a first overhead outlet, and a first dipleg, wherein the first entrance is in fluid communication with the gasifier outlet, and wherein the first dipleg is in fluid communication with the solids recycle inlet; a second cyclone having a second entrance, a second overhead outlet, and a second dipleg, wherein the second entrance is in fluid communication with the first overhead outlet; and a thermal reformer comprising a first zone, a first zone inlet, an oxygen inlet, a second zone, and a second zone inlet, wherein the first zone inlet is in fluid communication with the second dipleg, wherein the second zone inlet is in fluid communication with the second overhead outlet, and wherein the first zone has a cross section smaller than the second zone.

[0118] Clause 30. The system for gasification of clause 29, wherein the system further comprises a pressure reduction device between the second overhead outlet and the first zone of the thermal reformer, wherein the pressure reduction device comprises at least one of a venturi flow restrictor or a high temperature gate valve.

[0119] Clause 31. The system for gasification of clause 29 or 30, wherein the system further comprises: a cooling device in fluid communication with the second zone of the thermal reformer, wherein the cooling device comprises at least one of a convection cooler, partial quench cooler, and a full water quench cooler.

[0120] Clause 32. The system for gasification of any of clauses 29 through 31, wherein the cooling device does not comprise a radiant cooler.

[0121] Clause 33. The system for gasification of any of clauses 29 through 32, wherein the system further comprises: a synthesis gas conversion stage including at least one of a methanol synthesis catalyst or Fischer-Tropsch synthesis catalyst.

[0122] Clause 34. The system for gasification of any of clauses 29 through 33, wherein the second dipleg is in fluid communication with the first zone via a reformer fluid input conduit, wherein the fluid input conduit includes a methane recycle inlet and the synthesis gas conversion stage includes a methane outlet in fluid communication with the methane recycle inlet.

[0123] Clause 35. The system for gasification of any of clauses 29 through 34, wherein the system further comprises a pressure swing absorption stage including an absorbent bed.

[0124] Clause 36. The system for gasification of any of clauses 29 through 35, wherein the second dipleg is in fluid communication with the first zone via a reformer fluid input conduit, wherein the fluid input conduit includes a methane recycle inlet and the pressure swing absorption stage includes a methane outlet in fluid communication with the methane recycle inlet.

[0125] Clause 37. The system for gasification of any of clauses 29 through 36, wherein the second zone of the thermal reformer has a second 02 inlet.

[0126] Clause 38. The system for gasification of any of clauses 29 through 37, wherein the first zone has a cross sectional area smaller than the second zone.

[0127] Clause 39. The system for gasification of any of clauses 29 through 38, wherein the first zone is positioned above the second zone in a vertical axis.

Claims

CLAIMSWhat is claimed is:

1. A method for gasification of solids comprising: exposing a feed stock to a fluidized bed of particles under gasification conditions in a reactor vessel to generate a gasifier effluent comprising syngas, methane (CH4), char, and tar; passing at least a portion of the gasifier effluent into a char-separation cyclone that forms an overhead effluent and a dipleg effluent, the overhead effluent including syngas, tar, and CH4, and the dipleg effluent including char; passing the dipleg effluent into a first zone of a thermal reformer under first thermal reforming conditions to form an intermediate effluent, the first zone having a stream of oxygen (O2) injected therein, the first thermal reforming conditions comprising a temperature of l,320°C to l,700°C, the stream of O2 comprising 30mol% - 60mol% of a stoichiometric need of O2 for complete combustion of the dipleg effluent; converting at least a portion of the dipleg effluent into a partial oxidation product within the first zone; and passing the overhead effluent and the partial oxidation product into a second zone of the thermal reformer under second thermal reforming conditions to form a reformer effluent, the second thermal reforming conditions comprising a temperature of about 845°C to l,200°C.

2. The method for gasification of claim 1 , wherein passing at least a portion of the gasifier effluent into the char- separation cyclone comprises: passing a first portion of the gasifier effluent into a first cyclone to form a first cyclone effluent; and passing at least a portion of the first cyclone effluent into the char-separation cyclone.

3. The method for gasification of any of the above claims, wherein the method further comprises: injecting a second stream of O2 into the second zone, the second stream of O2 comprising 30mol% - 60mol% of the stream of O2 injected into the first zone of the thermal reformer.

4. The method for gasification of any of the above claims, wherein a temperature differential between effluent exiting the first zone of the thermal reformer and effluent exiting the second zone of the thermal reformer is at least 120°C, optionally but preferably at least 475 °C5. The method for gasification of claim 4, wherein the at least a portion of the dipleg effluent is conveyed to the first zone using a lift gas.

6. The method for gasification of claim 5, wherein the lift gas comprises a) steam, CO, CO2, or a combination thereof, b) CH4, at least a portion of the CH4 in the lift gas comprising CH4 recycled from the reforming effluent, the at least a portion of the CH4 in the lift gas optionally being recycled from the effluent of the thermal reformer, or c) a combination of a) and b).

7. The method for gasification of claim 6, wherein the method further comprises: passing at least a portion of the reforming effluent into a cooling device without passing the at least a portion of the reforming effluent into a radiant cooler system, wherein the cooling device comprises at least one of a radiant cooler, partial quench cooler, and a full water quench cooler.

8. The method for gasification of claim 6 or 7, wherein the first zone converts at least 70% CH4 into H2 and carbon oxides, or at least 80%, or at least 85%, or at least 90%, or at least 95%, or at least 98%.

9. The method for gasification of any of claims 6 to 8, wherein capturing CH4 from the cooling device comprises one or more of: i) passing a cooled effluent from the cooling device into a synthesis process and separating the CH4 from the effluent from the synthesis process, wherein the synthesis process comprises one or more of methanol synthesis and Fischer-Tropsch synthesis; ii) passing a cooled effluent from the cooling device into a pressure swing absorption vessel; and hi) generating power from at least a portion of the CH4, syngas, or a combination thereof.

10. The method for gasification of any of the above claims, further comprising: passing the effluent collected from the first outlet of the second cyclone dipleg through a pressure reduction device prior to passage into a first zone of a thermal reformer, the pressure reduction device optionally comprising at least one of a static venturi type flow restriction and a high temperature gate value.

11. The method for gasification of any of the above claims, wherein the method further comprises injecting a stream of renewable natural gas (RNG) into the first zone; or wherein the first zone and the second zone are in one vessel of the thermal reformer, and wherein the first zone has a cross sectional area smaller than the second zone; or a combination thereof.

12. A system for gasification of biosolids, the system comprising: a fluidized bed gasifier comprising a gasifier outlet, a solids recycle inlet; a first cyclone having a first entrance, a first overhead outlet, and a first dipleg, wherein the first entrance is in fluid communication with the gasifier outlet, and wherein the first dipleg is in fluid communication with the solids recycle inlet; a second cyclone having a second entrance, a second overhead outlet, and a second dipleg, wherein the second entrance is in fluid communication with the first overhead outlet; and a thermal reformer comprising a first zone, a first zone inlet, an oxygen inlet, a second zone, and a second zone inlet, wherein the first zone inlet is in fluid communication with the second dipleg, wherein the second zone inlet is in fluid communication with the second overhead outlet, and wherein the first zone has a cross section smaller than the second zone.

13. The system for gasification of claim 12, wherein the system further comprises a pressure reduction device between the second overhead outlet and the first zone of the thermal reformer, wherein the pressure reduction device comprises at least one of a venturi flow restrictor or a high temperature gate valve.

14. The system for gasification of claim 12 or 13, wherein the system further comprises: a cooling device in fluid communication with the second zone of the thermal reformer, wherein the cooling device comprises at least one of a convection cooler, partial quench cooler, and a full water quench cooler; or wherein the cooling device does not comprise a radiant cooler; or a combination thereof.

15. The system for gasification of claim 14, wherein the system further comprises: a synthesis gas conversion stage including at least one of a methanol synthesis catalyst or Fischer-Tropsch synthesis catalyst, wherein the second dipleg is in fluid communication with the first zone via a reformer fluid input conduit, and wherein the fluid input conduit includes a methane recycle inlet and the synthesis gas conversion stage includes a methane outlet in fluid communication with the methane recycle inlet.

16. The system for gasification of any of the claims 12 to 15, wherein the system further comprises a pressure swing absorption stage including an absorbent bed, wherein the second dipleg is in fluid communication with the first zone via a reformer fluid input conduit, wherein the fluid input conduit includes a methane recycle inlet and the pressure swing absorption stage includes a methane outlet in fluid communication with the methane recycle inlet.

17. The system for gasification of any of claims 12 to 16, wherein the second zone of the thermal reformer has a second O2 inlet, or wherein the first zone is positioned above the second zone in a vertical axis, or a combination thereof.

Images