Tar and oil management in gasification processes.

Abstract

Disclosed are gasification processes in which tar and oil present in gasifier effluent (gasifier effluent tar) are effectively removed by adsorption onto a solid sorbent or, optionally, converted by contact with a solid catalyst. In either case, certain aspects relate to advantageous control of the adsorbed tar and catalytic coke, particularly in terms of (i) how the solid sorbent or solid catalyst can be "deployed" throughout the process and / or (ii) the conditions to which these materials can be exposed, to provide significant benefits. These include improved process integration with the ability to recover the hydrogen and carbon values ​​of the adsorbed tar and catalytic coke and / or reduce CO2 emissions.

Description

[Technical Field]

[0001] Aspects of the present invention relate to gasification processes in which tar and oil in gasifier effluent are effectively managed by adsorption using solid sorbents, thereby enabling the recovery of a high-quality syngas product. Further aspects relate to methods of utilizing, replacing, and / or regenerating the solid sorbents, e.g., to achieve further process integration objectives. [Background technology]

[0002] Coal gasification has been carried out industrially for over 100 years to produce synthesis gas (syngas), which can be further processed into transportation fuels. More recent efforts to develop energy independence with reduced greenhouse gas emissions have led to great interest in using biomass as a gasification feed and thereby a potential alternative source of synthesis gas, as well as its downstream conversion products. These include renewable natural gas (RNG) or biomethane, in addition to higher molecular weight hydrocarbons.

[0003] Typically, biomass gasification is carried out by partial oxidation in the presence of a suitable oxidizing gas containing oxygen and other possible components, such as steam. Gasification at high temperatures and pressures, optionally in the presence of a catalytic material, produces a waste stream containing hydrogen and oxides of carbon (CO, CO), as well as hydrocarbons such as methane. This waste stream, which may be referred to as syngas in terms of its H and CO content, is typically treated to remove numerous undesirable components, which may include particulates, alkali metals, and sulfur compounds. Such treatment steps may be necessary to render the significant concentrations of H and CO / CO from the gasifier waste / syngas product suitable for downstream conversion into value-added products, such as higher molecular weight hydrocarbons and / or alcohols of various carbon numbers via Fischer-Tropsch conversion, or RNG via catalytic methanation, which increases the methane content in the resulting RNG stream.

[0004] The presence of heavy molecules, commonly referred to as tars and oils, in gasifier effluent at concentrations ranging from tens of parts per million (ppm) to several percent by weight is also undesirable. Similar to the syngas contaminants discussed above, tars and oils interfere with subsequent processing steps that utilize catalysts that function optimally (e.g., from a stability standpoint) with pure feed gas. Furthermore, these by-products of gasification present significant challenges in terms of their tendency to condense from the vapor phase onto cold surfaces encountered downstream of the gasifier, including the surfaces of equipment used to enhance the syngas into end products. Physical deposition of tars and oils is known to cause fouling / clogging of process lines, valves, reactors, and other equipment.

[0005] Given these considerations, the art has adopted a number of approaches to remove tar and oil downstream of gasifiers, where they are produced as harmful by-products. One common technique involves passing the gasifier effluent through a liquid medium, such as a bio-oil liquid, to scrub this effluent of tar and oil (based on their preferential solubility), and then combusting this liquid after it has been consumed, thereby emitting flue gas CO2. While oil scrubbing systems are effective in reducing the tar and oil content in syngas to very low levels, they are complex to operate, and the management of moisture and fresh and spent oil presents numerous technical and economic challenges.

[0006] An alternative method for avoiding the separate emissions resulting from the regeneration of tar-saturated oil relies on catalytic or thermal treatment of tar- and oil-containing synthesis gas to directly convert high molecular weight by-products into synthesis gas components during normal operation. However, catalytic processes require additional steam and / or oxygen reactants, and known catalysts for this conversion are not only highly susceptible to coking, which limits their useful life, but also require expensive catalytic metals that can be easily deactivated (made ineffective) by even trace amounts of impurities such as sulfur. Operation of catalytic tar / oil conversion reactors is complicated by the presence of entrained solid particles (e.g., ash) in the synthesis gas; therefore, such operation requires either upstream filtration or special modifications to allow the particles to pass through. These and other difficulties associated with tar and oil removal by catalyst destruction are manifested by the fact that this technology is not currently offered with commercial performance guarantees. Generally, attempts to carry out catalytic conversion of tar and oil have proven uneconomical and / or technically unfeasible.

[0007] Thermal methods for cracking tar and oil involve subjecting tar- and oil-laden syngas to very high temperatures in the presence of additional oxygen downstream of the gasifier input. Significant problems arising from these combustion approaches that must be addressed in an appropriate manner are heat recovery and syngas cooling. For example, because sufficient processing temperatures are generated to melt biomass ash and other solid particles emanating from the gasifier that may be present in the syngas, complex and expensive heat exchange systems are required to cool the syngas without the molten ash and bed material covering the heat exchange surfaces or damaging the protective refractory lining within the vessel. Beyond these specialized equipment requirements, further drawbacks of thermal tar and oil destruction include syngas consumption, which reduces overall product yields, and substantially increased oxygen requirements beyond the theoretical amount needed for gasification alone. Each of these features adversely affects process economics.

[0008] The current state of the art would substantially benefit from an effective solution to the problem of removing tar and oil from gasifier effluent or syngas products that overcomes the drawbacks of known techniques discussed above. These by-products, derived from the various carbonaceous feeds (e.g., coal and biomass) processed by gasification, significantly complicate downstream operations, including compression, heat transfer, and conversion of the syngas into value-added products and chemicals. Summary of the Invention

[0009] Aspects of the present invention effectively remove tar and oil present in gasifier effluent (gasifier effluent tar) by adsorption onto a solid sorbent. In some cases, this suitable solution can advantageously allow controlled management of the adsorbed tar and oil, particularly in terms of (i) how the material may be "placed" throughout the process and / or (ii) the conditions to which the material may be exposed, to provide important benefits. These include improved process integration with the ability to recover and monetize the hydrogen and carbon values ​​of the adsorbed tar and oil and / or reduce CO2 emissions compared to conventional methods. As mentioned above, a further advantage lies in the possibility of avoiding additional process inputs and consumption of oxygen and steam required for known processing steps such as catalytic conversion and combustion of spent liquid sorbent.

[0010] Another aspect relates to solid sorbents, including tar adsorbent materials such as high-surface-area acidic materials, through which gasifier effluent may be passed to facilitate adsorptive trapping of tar and oil in the effluent and provide a tar-depleted or substantially tar-free syngas. Depending on the specific tar adsorption conditions, adsorptive trapping may be achieved by limited (partial) or substantial chemical conversion of the tar and oil, including conversion to condensed coke retained by the solid sorbent and / or conversion to syngas components (e.g., additional H and / or CO). Either of these conversion(s) results in effective removal of tar and oil from the syngas, potentially with the added benefit of increased yield. Suitable tar adsorbent materials described herein possess the requisite physical and chemical properties necessary to bind tar and oil for extended operation, optionally after some cooling, at the high temperatures characteristic of gasifier effluent. These properties include sufficient surface area, acidity, structural integrity, abrasive resistance, thermal stability, and regenerative potential.

[0011] A further aspect relates to the regeneration of these solid adsorbents after a period of normal operation or running, during which full utilization results in a loss of adsorption capacity and / or deactivation relative to the desired chemical conversion. The need to regenerate such "spent" solid adsorbents generally results from the deposition of tar and oil, optionally in combination with their further conversion to condensed coke and other carbonaceous products, as well as the tar and oil themselves, remaining on the solid adsorbent and thereby separated from the syngas product flow. In the case of conversion, the chemical conversion pathways generally proceed at the surface of the solid adsorbent, although these reactions, as well as the initial adsorption of tar and oil, can occur within the pores of the solid adsorbent as well.

[0012] A more specific aspect relates to the ability to integrate into the process the handling of spent sorbent, i.e., changing or shifting its "location" in terms of the process flow and the overall system, followed by its regeneration at a different location and / or under different conditions, which can have significant effects. According to certain embodiments, the normal operation or running of the solid sorbent can occur downstream of the gasifier, while the regeneration of the spent sorbent can occur upstream of the gasifier. The terms "upstream" and "downstream" refer to the general flow of gas from the gasifier feed, through other parts of the gasification process, to the gasifier effluent. Those skilled in the art will readily understand the meaning of these terms and will understand that changing or shifting the location of the solid sorbent (e.g., fresh sorbent, spent sorbent, or regenerated sorbent) does not necessarily require a change in its physical location, but can be accomplished with appropriate piping / valves to manipulate the process flow.

[0013] For example, a tar adsorber containing solid sorbent and placed in normal operation or service can be separated or removed from such normal operation or service, optionally along with other components of a larger tar adsorber subsystem, after a sufficient period of use during which the solid sorbent becomes spent and requires regeneration to again achieve satisfactory adsorption performance. This tar adsorber may then be contacted with a different process stream, effectively changing its position within the process under various conditions, such as regeneration conditions as opposed to tar adsorption conditions. In an exemplary embodiment, the process stream for contacting the spent sorbent for regeneration, i.e., under regeneration conditions, may contain primarily a mixture of HO, CO, and O, and / or may contain all or a portion of these components that are subsequently fed to the gasifier, to the extent that these components are not converted under regeneration conditions. In this manner, the tar adsorber and spent sorbent may be placed upstream of the gasifier for regeneration, which may include the net production of CO by combustion / oxidation of the adsorbed tar and oil and / or their further conversion products, as described above. However, with regeneration performed upstream of the gasifier, some or all of this CO and other components of the regeneration effluent may be processed within the gasifier and converted, at least in part, to, for example, equilibrium amounts of CO as a result of the water-gas shift (WGS) reaction. Such capture and utilization of CO to enhance synthesis gas yields contrasts with conventional processes that optionally vent CO present in the flue gas to the atmosphere after burning (e.g., flaring) the flue gas.

[0014] Routing the regeneration effluent to the gasifier may be accomplished by conducting the regeneration at a pressure higher than the gasifier pressure, for example, by utilizing a source of pressurized steam for input to a vessel containing the solid sorbent being regenerated upstream of the gasifier. This can optionally avoid the need for a compressor between the vessel and the gasifier, while realizing thermal efficiency benefits (e.g., recovery of regeneration heat for input / use in the gasifier, etc.) in addition to the CO capture and utilization described above. Methods of integration include diverting at least a portion of the makeup gas composition that is a constituent of an oxygen-containing gasifier feed, such as fresh gasifier feed (e.g., including HO, CO, O), to a vessel used for regenerating the spent sorbent, and / or using at least a portion of the regeneration effluent as a constituent of the oxygen-containing gasifier feed. To perform regeneration in an efficient manner using readily available gas compositions, as well as to recover the heat and carbon content (e.g., as CO) in the regeneration effluent, such methods are applied not only to solid sorbents, but also to liquid absorbents and solid catalysts, either of which may be used for tar regeneration in the gasification process.

[0015] Embodiments of the present invention relate to processes for the gasification of a carbonaceous feed (e.g., coal or biomass) to produce a synthesis gas product. An exemplary process includes contacting the carbonaceous feed with an oxygen-containing gasifier feed under gasification conditions in a gasifier to provide a gasifier effluent containing gasifier effluent tar. Such a process further includes contacting at least a portion of the gasifier effluent with at least a first bed of a solid sorbent under tar adsorption conditions in a tar adsorber to adsorb at least a portion of the gasifier effluent and provide a tar adsorber effluent having a reduced amount of tar. In some embodiments, the tar adsorber effluent may be the same as the synthesis gas product. In other embodiments, the exemplary process may further include recovering a synthesis gas product from the tar adsorber effluent after one or more additional processing steps, such as cooling and / or purifying (e.g., washing to remove acid gases, such as CO) the tar adsorber effluent.

[0016] More specific embodiments include replacing all or a portion of a first bed of solid sorbent based on an indication of sufficient utilization (e.g., hours of operation) that causes the solid sorbent to become spent solid sorbent. For example, the first bed of solid sorbent can be replaced with a bed of fresh sorbent (not used for tar adsorption) or a second bed of solid sorbent that is a bed of regenerated solid sorbent (that has been used for tar adsorption but subsequently regenerated). The step of "replacing" is meant to encompass the physical replacement of the solid sorbent contained in a vessel such as a tar adsorber. The term is also meant to encompass the rerouting of process flow, whereby a vessel that was a first "in-service" tar adsorber containing a first bed of solid sorbent may be effectively "removed" from tar adsorption operations and "replaced" in terms of the rerouted process flow with another vessel, which may be a second "regenerated" tar adsorber containing a second bed of solid sorbent. Optionally, such a second tar adsorber may then be effectively removed from the regeneration operation and replaced with the first tar adsorber in view of the rerouted process flow.

[0017] Thus, an exemplary process may include, for example, at least two tar adsorber units operated simultaneously during at least a portion of the time during which syngas is produced, with one tar adsorber operating to adsorb tar from the gasifier effluent and the other operating to regenerate spent sorbent. The tar adsorber units may alternate between a location featuring an operational tar adsorber (e.g., downstream of the gasifier) ​​and a location featuring a regenerated tar adsorber (e.g., upstream of the gasifier) ​​depending on the rerouted process flow. While different types of solid adsorber units may be used for different tar adsorber units, the tar adsorber units typically each contain the same type of solid adsorber. Different types of solid adsorber units may be used interchangeably in a single tar adsorber (e.g., within separate fixed beds within such a tar adsorber) or in a series arrangement of adsorber units, each containing a different type of solid adsorber unit (e.g., different types selective for different specific compounds or classes of compounds present in the gasifier effluent). Effective and advantageous process integration can be achieved according to specific embodiments in which the regeneration carried out in the regenerated tar adsorber containing the second bed of solid sorbent comprises contacting a first portion of the fresh gasifier feed described herein with the bed, and the oxygen-containing gasifier feed comprises a second portion of the fresh gasifier feed. Alternatively, or in combination, the oxygen-containing gasifier feed may comprise at least a portion of the regeneration effluent resulting from the regeneration of the second bed of solid sorbent under regeneration conditions. This regeneration effluent may more specifically comprise CO, CO2, HO, and / or H2 resulting from the oxidation, pyrolysis, and / or reformation of the aforementioned tars and oils and / or their further conversion products that were adsorbed onto the second bed of solid sorbent from the gasifier effluent when the tar adsorber containing the bed was previously in a position characterized by an operational tar adsorber.

[0018] Another more specific embodiment relates to a process for gasifying a carbonaceous feed, where such process is integrated with tar adsorption and solid sorbent regeneration. The process includes contacting the carbonaceous feed with an oxygen-containing gasifier feed under gaseous conditions in a gasifier to provide a gasifier effluent containing gasifier effluent tar. The process further includes alternating first and second beds of solid sorbent between (i) tar adsorption by contacting the first and second beds with the gasifier effluent under tar adsorption conditions to adsorb at least a portion of the gasifier effluent and provide a tar adsorber effluent having a reduced amount of tar, and (ii) regeneration by contacting the first and second beds with a first portion of fresh gasifier feed under regeneration conditions to oxidize, pyrolyze, and / or reform at least a portion of the adsorbed tar to CO, CO2, HO, and / or H2 and provide a regenerated effluent. In some embodiments, the tar adsorber effluent may be the same as the synthesis gas product. In other embodiments, the exemplary process may further include recovering a synthesis gas product from the tar adsorber effluent, for example, after one or more additional processing steps, such as cooling and / or purifying (e.g., washing) the tar adsorber effluent. Effective and advantageous process integration can be achieved according to specific embodiments in which the oxygen-containing gasifier feed comprises (i) a second portion of the fresh gasifier feed, and / or (ii) at least a portion of the regenerated effluent.

[0019] Further embodiments relate to similar processes described in more detail below in which, instead of tar adsorption, tar conversion is integrated with gasification to achieve the same or similar benefits, particularly for processes that are further integrated with regeneration of the solid catalyst used in tar conversion.

[0020] These and other embodiments, aspects, and advantages of the present invention will become apparent from the detailed description that follows.

[0021] Exemplary embodiments of the present invention and their advantages may be more fully understood by referring to the following description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0022] [Figure 1] FIG. 1 shows a flow scheme illustrating a specific embodiment of a carbonaceous feed gasification process in which tar adsorption is carried out by contacting the gasifier effluent with a first bed of solid adsorbent contained in a first tar adsorber.

[0023] The process is integrated with the regeneration of the second bed of solid adsorbent contained in the second tar adsorber and utilizes appropriate piping / valving to manipulate the process flow, thereby allowing the first and second tar adsorber and their respective beds of solid adsorbent to alternate between tar adsorption and regeneration positions and functions.

[0024] For ease of explanation and understanding, the figures are presented in simplified overviews. Some associated equipment, such as vessels, heat exchangers, valves, instruments, utilities, etc., is not shown because its specific description is not necessary for implementing or understanding various aspects of the present invention. Such equipment will be readily apparent to those skilled in the art. Other processes for producing a synthesis gas product according to other embodiments within the scope of the present invention, whose structure and composition are determined in part for specific process purposes, will likewise be apparent. DETAILED DESCRIPTION OF THE INVENTION

[0025] As used herein, the expressions "wt. %" and "mol. %" are used to denote weight percentage and mole percentage, respectively. The expressions "wt-ppm" and "mol. ppm" denote weight and mole fraction, respectively. For an ideal gas, "mol. %" and "mol. ppm" correspond to volume percent and parts per million by volume, respectively.

[0026] As used herein, the term "substantially" refers to a degree of at least 95%. For example, the phrase "substantially all" can be replaced with "at least 95%." The phrase "at least a portion" is meant to encompass, in certain embodiments, "at least 50% of," "at least 75% of," "at least 90% of," and, in preferred embodiments, "all."

[0027]

[0003] Embodiments of the present invention relate to a process for gasifying a carbonaceous feed to produce a synthesis gas product. An exemplary process includes contacting a carbonaceous feed in a gasifier with an oxygen-containing gasifier feed under gasification conditions and providing a gasifier effluent containing gasifier effluent tar, wherein at least a portion of the gasifier effluent tar is adsorbed by contacting the gasifier effluent with a solid sorbent. The term "gasifier effluent tar" is referred to in the art as "tar" and "oil" and encompasses hydrocarbon and oxygenated hydrocarbon-containing compounds having molecular weights greater than that of methane and present in effluent gases produced by the gasification of coal and biomass. Certain types of these relatively large molecular weight compounds are further characterized as problematic due to their tendency to condense and coat internal surfaces of processing equipment downstream of the gasifier, creating problems related to fouling, corrosion, and / or clogging. Other types of these compounds, such as ethane, ethylene, and acetylene, do not condense from the gasifier effluent, but nevertheless "bind" hydrogen and carbon with the effect of reducing the overall yield of H2 and CO as desired components of synthesis gas. Generally, "gasifier effluent tar" refers to at least hydrocarbons and oxygenated hydrocarbons having six or more carbon atoms (C6 + The term "carbon-based solvents" is intended to include hydrocarbons, including but not limited to hydrocarbons, and oxygenated hydrocarbons, of which benzene, toluene, xylene, naphthalene, phenol, and cresol are illustrative examples.

[0028] In the case of "gasifier effluent tar" adsorbed on the surface or within the pores of the solid sorbents described herein, the term is meant to encompass not only the compounds described above, but also further conversion products of these compounds, such as condensed coke and other carbonaceous products that are retained within the solid sorbent and separated from the flowing syngas product. Upon regeneration of the solid sorbent, such further conversion products, such as the tar and oil itself, can be oxidized, pyrolyzed, and / or reformed to provide CO, CO, HO, and / or H, which can be beneficially returned in the regeneration effluent and beneficially utilized throughout the process. Solid adsorbents for adsorbing gasifier waste tar.

[0029] Exemplary solid sorbents include tar adsorbent materials that provide suitable physical and chemical properties for effective adsorption performance under conditions, including the high temperatures characteristic of gasifier effluent. These properties generally have a reactivity of at least about 10 m 2 / g (e.g., about 10 m 2 / g~about 300m 2 / g), typically at least about 50m 2 / g (e.g., about 50m 2 / g ~ approx. 250m 2 / g), and in many cases at least about 100m 2 / g (e.g., about 100m 2 / g~about 200m 2 The adsorbent may comprise a surface area sufficient for adsorption, such as 1000 sq ft / g. In some embodiments, these surface areas may be representative of the solid adsorbent as a whole. Surface area may be measured according to the BET (Brunauer, Emmett, and Teller) method based on nitrogen adsorption (ASTM D1993-03(2008)).

[0030] Exemplary tar adsorbent materials include zeolites (zeolitic molecular sieves) and non-zeolitic molecular sieves (zeotypes), as well as amorphous solid materials such as amorphous aluminosilicates and amorphous metal oxides. Specific zeolites or non-zeolitic molecular sieves may have a structure type selected from the group consisting of CHA, TON, FAU, FER, BEA, ERI, MFI, MEL, MTW, MWW, MOR, LTL, LTA, EMT, MAZ, MEI, AFI, and AEI, preferably one or more of CHA, TON, FAU, FER, BEA, ERI, and MFI. The structures of zeolites with these and other structure types are described in Meier, W.M., et al., Atlas of Zeolite Structure Types, 4 th Ed., Elsevier: Boston (1996), and further references are provided. Specific examples include SSZ-13 (CHA structure), zeolite Y (FAU structure), zeolite X (FAU structure), MCM-22 (MWW structure), zeolite beta (BEA structure), ZSM-5 (MFI structure), and ZSM-22 (TON structure), with zeolite beta and ZSM-5 being exemplary.

[0031] Non-zeolitic molecular sieves (zeotypes) include ELAPO molecular sieves which have an empirical chemical composition on an anhydrous basis represented by the formula: (ELxAlyPz)O2

[0032] where EL is an element selected from the group consisting of silicon, magnesium, zinc, iron, cobalt, nickel, manganese, chromium and mixtures thereof, x is the mole fraction of EL and is typically at least 0.005, y is the mole fraction of aluminum and is at least 0.01, z is the mole fraction of phosphorus and is at least 0.01, and x + y + z = 1. When EL is a mixture of metals, x represents the total mole fraction of such metals present. The preparation of various ELAPO molecular sieves is known, and examples of synthesis procedures and their final products are described in U.S. Pat. No. 5,191,141 (ELAPO), U.S. Pat. No. 4,554,143 (FeAPO), U.S. Pat. No. 4,440,871 (SAPO), U.S. Pat. No. 4,853,197 (MAPO, MnAPO, ZnAPO, CoAPO), U.S. Pat. No. 4,793,984 (CAPO), U.S. Pat. No. 4,752,651, and U.S. Pat. No. 4,310,440. Preferred ELAPO molecular sieves are SAPO and ALPO molecular sieves. Generally, ELAPO molecular sieves are synthesized by hydrothermal crystallization from a reaction mixture containing sources of EL, aluminum, phosphorus, and a templating agent. The sources of EL are metal salts of the EL elements defined above, such as their chlorides or nitrates. When EL is silicon, the preferred source is fumed silica, colloidal silica, or precipitated silica. Preferred reactive sources of aluminum and phosphorus are pseudoboehmite alumina and phosphoric acid. Preferred templating agents are amines and quaternary ammonium compounds. A particularly preferred templating agent is tetraethylammonium hydroxide (TEAOH).

[0033] A specific tar adsorbent material is an ELAPO molecular sieve, where EL is silicon; such molecular sieves are referred to in the art as SAPO (silica aluminophosphate) molecular sieves. In addition to those described in U.S. Pat. No. 4,440,871 and U.S. Pat. No. 5,191,141, SAPO molecular sieves that may be used are described in U.S. Pat. No. 5,126,308. Among the specific crystal structures described in U.S. Pat. No. 4,440,871, SAPO-34, i.e., structure type 34, represents a specific tar adsorbent material. The SAPO-34 structure (CHA structure) is characterized by its ability to adsorb xenon but not isobutane, which indicates that its pore size is approximately 4.2 Å. Thus, exemplary solid adsorbents may include SAPO-34 or other SAPO molecular sieves, such as SAPO-17, which are also disclosed in U.S. Pat. No. 4,440,871 and have a structure characterized by adsorption of oxygen, hexane, and water, but not isobutane, and exhibit pores greater than about 4.3 Å and smaller than about 5.0 Å. Without being bound by theory, it is believed that the acidity of SAPO-34 facilitates effective adsorption of gasifier effluent tar. According to certain embodiments, the solid adsorbent may include ZSM-5 or SSZ-13 zeolites (zeolitic molecular sieves), or non-zeolitic molecular sieves (zeotypes) of SAPO-34 or SAPO-17. For any particular zeolitic or non-zeolitic molecular sieve that may be used as a component of the solid adsorbents described herein, it may be present in any form in which the ion exchange sites are in their hydrogen form or otherwise exchanged with suitable cations, non-limiting examples of which include cations of alkali metals (e.g., Na + ), alkaline earth metal cations (e.g., Ca 2+ ), and ammonium cation (NH4 + For example, the zeolite may be SSZ-13 in the hydrogen form (HSSZ-13), and the non-zeolitic molecular sieve may be SAPO-34 in the hydrogen form (HSAPO-34).

[0034] In the case of solid adsorbents comprising zeolites or non-zeolitic molecular sieves, such solid adsorbents may be more specifically defined as solid acid adsorbents based on the acidity exhibited by the zeolites or non-zeolitic molecular sieves. The acidity of a given zeolite or non-zeolitic molecular sieve may be measured, for example, by temperature-programmed desorption (TPD) of a constant amount of ammonia (ammonia TPD) from an ammonia-saturated sample of the material over a temperature range of 275°C (527°F) to 500°C (932°F), above the temperature at which ammonia is physically adsorbed. Thus, the amount of acid sites in millimoles of acid sites per gram of material (mmol / g) corresponds to the number of millimoles of ammonia desorbed per gram of material over this temperature range. Exemplary zeolitic or non-zeolitic molecular sieves, or alternatively, exemplary tar adsorbing materials or solid adsorbents, have at least about 15 μmol / g (e.g., about 15 to about 75 μmol / g) of acid sites, or at least about 25 μmol / g (e.g., about 25 to about 65 μmol / g) of acid sites, as measured by ammonia TPD. For zeolitic molecular sieves, acidity is a function of the silica-to-alumina (SiO / AlO) molar framework ratio, and in embodiments where the solid adsorbent comprises a zeolitic molecular sieve, the silica-to-alumina molar framework ratio can be less than about 60 (e.g., about 1 to about 60), or less than about 40 (e.g., about 5 to about 40).

[0035] Instead of, or optionally in combination with, one or more zeolites and / or one or more non-zeolitic molecular sieves, the solid sorbent may comprise, or optionally may further comprise, an amorphous aluminosilicate or refractory metal oxide. Regarding the latter type of possible component of the solid sorbent, exemplary refractory metal oxides include those selected from the group consisting of aluminum oxide, silicon oxide, titanium oxide, zirconium oxide, magnesium oxide, calcium oxide, iron oxide, vanadium oxide, chromium oxide, nickel oxide, tungsten oxide, and strontium oxide. Exemplary solid sorbents, and more specifically solid acid sorbents, include such metal oxides modified with iron sulfide, for example, in the case of sulfurized zirconia, or other solid acids, including those conventionally used in hydrocarbon alkylation. In exemplary embodiments, the solid adsorbent may include (a) one or more zeolite molecular sieves (e.g., a single type of zeolite molecular sieve) or (b) one or more non-zeolite molecular sieves (e.g., a single type of non-zeolite molecular sieve), optionally in combination with (c) one or more refractory metal oxides (e.g., a single type of refractory metal oxide), in which case (a) or (b), and optionally (c), may be present in an amount greater than about 75 wt. % (e.g., from about 75 wt. % to about 99.9 wt. %), or greater than about 90 wt. % (e.g., from about 90 wt. % to about 99 wt. %), or optionally in a total amount, based on the weight of the solid adsorbent. For example, according to more specific embodiments, only (a) or (b) may be present in these exemplary amounts, e.g., in the specific case of only a single type of zeolite molecular sieve or only a single type of non-zeolite molecular sieve. However, in other embodiments, only (c) may be present in these exemplary amounts. Other exemplary tar adsorbing materials include (i) one or more clays, such as naturally occurring clays, including those categorized in the group of kaolinite, illite, and montmorillonite, and / or (ii) one or more minerals, such as dolomite, olivine, and / or limestone.The one or more clay(s) and / or one or more mineral(s) may also be present individually or in the aggregate in these exemplary amounts based on the weight of the solid sorbent.

[0036] According to some embodiments, the solid sorbent may have little or no activity for the catalytic conversion of gasifier effluent tar, and more specifically, for the conversion of this tar or its further conversion products to CO, CO, HO, and / or H. Such embodiments relate to important advantages that can be obtained when the solid sorbent functions as a "poor" catalytic agent, or in some cases even as a non-catalytic agent, but nevertheless functions as an effective sorbent. As discussed above, these advantages can result in an overall simplicity compared to processes that rely on catalytic conversion of gasifier effluent tar, which are associated with (i) the requirement for additional steam and / or oxygen reactant input, (ii) rapid catalyst deactivation by sulfur and other trace heteroatoms in the carbonaceous feed, and (iii) other adjustments required to accommodate the catalytic reactor, which add complexity and cost. A further advantage relates to the ability to retain or "trap" tar and oil and their further conversion products for subsequent handling in a controlled manner that may better preserve and utilize the carbon and hydrogen values ​​from the carbonaceous feed (e.g., by increasing the yield of synthesis gas).

[0037] Yet further advantages can result from the ability to avoid the use of expensive catalytic materials in the solid sorbent formulation. For example, according to some embodiments, the solid sorbent can include one or more metals (e.g., Ni, Co, Fe, and / or a noble metal) active for catalytic conversion of gasifier effluent tar under tar adsorption conditions present in a tar adsorber containing the solid sorbent in an amount, or total amount, of less than about 1 wt. %, less than about 0.5 wt. %, or less than about 0.1 wt. %, based on the weight of the solid sorbent. For example, the solid sorbent can include Ni in any of these amounts, Co in any of these amounts, Fe in any of these amounts, and / or a combination of Ni, Co, and Fe in any of these amounts. As a further example, the solid sorbent can include a noble metal (e.g., Pt) in any of these amounts, or two or more noble metals (e.g., Pt and Pd) in any of these amounts. Noble metals are understood in the art to refer to a class of oxidation-resistant, metallic elements that includes Pt, Rh, Ru, Pd, Ag, Os, Ir, and Au. In other embodiments, the amount of any metal(s) present in the solid adsorbent, other than the metals present in the zeolite, non-zeolitic molecular sieve, metal oxide, and / or clay as components of the solid adsorbent, or the total amount, may be less than about 1 wt. %, less than about 0.5 wt. %, or less than about 0.1 wt. %, based on the solid adsorbent. Taken together, the absence of one or more catalytic metals as components of the solid adsorbent may provide the basis for a composition that distinguishes a solid adsorbent from a solid catalyst. Additional performance-based and process flow-based distinctions are described herein as well.

[0038] Solid catalysts for converting gasifier waste tar. Armed with knowledge of the present disclosure, one skilled in the art will appreciate that certain embodiments disclosed herein may be applicable to, and may be even more advantageous when practiced in conjunction with, solid catalysts as an alternative to solid sorbents. Such embodiments are based more specifically on the ability to apply the principles described herein relating to the integration of solid sorbent regeneration with gasification to the integration of solid catalyst regeneration with gasification.

[0039] For example, certain embodiments of the present invention relate to a process for gasifying a carbonaceous feed to produce a synthesis gas product, the process comprising contacting the carbonaceous feed with an oxygen-containing gasifier feed under gaseous conditions in a gasifier to provide a gasifier effluent containing gasifier effluent tar. The process further comprises contacting at least a portion of the gasifier effluent with at least a first bed of solid catalyst under tar conversion conditions in a tar conversion reactor to convert at least a portion of the gasifier effluent tar and provide a reactor effluent having a reduced amount of tar. The process further comprises recovering a synthesis gas product from the reactor effluent. Based on an indication of sufficient utilization, at least a portion of the first bed of solid catalyst can be replaced with at least a portion of a second bed of solid catalyst after regeneration of the second bed of solid catalyst. This regeneration may include contacting a first portion of the fresh gasifier feed with a second bed of solid catalyst under regeneration conditions to provide a regeneration effluent comprising CO, CO2, HO, and / or H2 resulting from the oxidation, pyrolysis, and / or reformation of adsorbed tar and catalytic coke. Effective and advantageous process integration may be achieved through certain embodiments in which the oxygen-containing gasifier feed comprises the second portion of the fresh gasifier feed. Alternatively, or in combination, the oxygen-containing gasifier feed may comprise at least a portion of the regeneration effluent from the regeneration of the second bed of solid catalyst under regeneration conditions.

[0040] Another specific embodiment of the present invention relates to a process for gasifying a carbonaceous feed, such process being integrated with tar conversion and solid catalyst regeneration. The process includes contacting the carbonaceous feed with an oxygen-containing gasifier feed under gasification conditions in a gasifier and providing a gasifier effluent containing gasifier effluent tar. The process further includes alternating the first and second beds of solid catalyst between (i) tar conversion by contacting the first and second beds with the gasifier effluent under tar conversion conditions to convert at least a portion of the gasifier effluent tar and provide a reactor effluent having a reduced amount of tar, and (ii) regeneration by contacting the first and second beds with a first portion of fresh gasifier feed under regeneration conditions to oxidize, pyrolyze, and / or reform at least a portion of the adsorbed tar and catalyst coke to CO, CO2, HO, and / or H2 and provide a regeneration effluent. In some embodiments, the reactor effluent may be the same as the synthesis gas product. In other embodiments, the exemplary process may further include recovering a synthesis gas product from the reactor effluent, for example, after one or more additional processing steps, such as cooling and / or purifying (e.g., washing) the reactor effluent. Effective and advantageous process integration may be achieved through specific embodiments in which the oxygen-containing gasifier feed comprises (i) a second portion of the fresh gasifier feed, and / or (ii) at least a portion of the reclaimed effluent.

[0041] Thus, embodiments of the present invention relate to any of the gasification processes described herein that are integrated with regeneration, whether it be regeneration of a solid sorbent or regeneration of a solid catalyst. Thus, for any of the processes described herein that include a gasification step (in a gasifier) ​​and a tar adsorption step (in a tar adsorber), also disclosed are processes in which "tar adsorber" is replaced with "tar conversion reactor," "tar adsorption" is replaced with "tar conversion," "solid sorbent" is replaced with "solid catalyst," "tar adsorption conditions" is replaced with "tar conversion conditions," "adsorb" is replaced with "convert," "tar adsorber effluent" is replaced with "reactor effluent," and / or "adsorbed tar" is replaced with "adsorbed tar and catalytic coke." With respect to any of these disclosed processes involving gasification (in a gasifier) ​​and tar conversion (in a tar conversion reactor), unless otherwise specified, any of the conditions (e.g., gasification temperature), stream composition (e.g., syngas product composition), processing steps (e.g., centrifugation, filtration), performance parameters (e.g., tar remaining in the syngas product), and operating criteria (e.g., indices of full utilization) described with respect to processes involving gasification and tar adsorption are equally applicable.

[0042] In one or more aspects, such as with respect to surface area, acidity, and / or composition, exemplary solid catalysts may be the same as the solid adsorbents described above. For example, with respect to composition, the solid catalyst may include (a) one or more zeolite molecular sieves (e.g., a single type of zeolite molecular sieve) or (b) one or more non-zeolite molecular sieves (e.g., a single type of non-zeolite molecular sieve), where (a) or (b) is optionally combined with (c) one or more refractory metal oxides (e.g., a single type of refractory metal oxide). In this case, (a) or (b), and optionally (c), may be present in an amount greater than about 75 wt. % (e.g., from about 75 wt. % to about 99.9 wt. %), or greater than about 90 wt. % (e.g., from about 90 wt. % to about 99 wt. %), or optionally in a total amount, based on the weight of the solid catalyst. For example, according to more specific embodiments, only (a) or (b) may be present in these exemplary amounts, such as in the specific case of only a single type of zeolite molecular sieve or only a single type of non-zeolite molecular sieve. However, in other embodiments, only (c) may be present in these exemplary amounts. Other exemplary components of the solid catalyst include (i) one or more clays, such as naturally occurring clays, including those categorized in the group of kaolinite, illite, and montmorillonite, and / or (ii) one or more minerals, such as dolomite, olivine, and / or limestone. The one or more clay(s) and / or one or more mineral(s) may also be present, individually or in combined amounts, in these exemplary amounts based on the weight of the solid catalyst.

[0043] According to some embodiments, a given solid catalyst may be identical in all respects to a given solid sorbent described above, except that the solid catalyst may include one or more metals (e.g., Ni, Co, Fe, and / or a noble metal) that are active for catalytic conversion of gasifier effluent tar under tar conversion conditions present in a tar conversion reactor containing the solid catalyst. For example, such one or more metals may generally be present in the solid catalyst in an amount, or total amount, of about 1% to about 20% by weight, typically about 2% to about 15% by weight, and usually about 2% to about 10% by weight. For example, the solid catalyst may include Ni in any of these amounts, Co in any of these amounts, Fe in any of these amounts, and / or a combination of Ni, Co, and Fe in any of these amounts. As a further example, the solid catalyst may include a noble metal (e.g., Pt) in any of these amounts, or two or more noble metals (e.g., Pt and Pd) in any of these amounts. Further Exemplary Embodiments of the Gasification Process

[0044] The figure shows a flow scheme illustrating a specific embodiment of a process in which gasification in a gasifier 100 is integrated with tar adsorption in a tar adsorber 200 containing a solid sorbent as described herein to produce a synthesis gas product 40. As noted above, according to other embodiments, tar adsorption may alternatively be tar conversion carried out in a tar conversion reactor 200 containing a solid catalyst as described herein.

[0045] In an exemplary process for gasification of a carbonaceous feed 10 using a tar adsorber 200 to produce a syngas product 40, the carbonaceous feed may include coal (e.g., high-quality anthracite or bituminous coal, or lesser-quality subbituminous, lignite, or peat), petroleum coke, asphaltenes, and / or mobile petroleum residues, or other petroleum-derived materials. In a preferred embodiment, the carbonaceous feed may include biomass. The term "biomass" refers to renewable (non-petroleum-derived) material derived from living organisms that live on the Earth's surface or in the Earth's oceans, rivers, and / or lakes. Exemplary biomass may include any plant material or mixture of plant materials, such as hardwood (e.g., whitewood), softwood, hardwood or softwood bark, lignin, algae, and / or lemna (seaweed). Energy crops or other agricultural residues (e.g., logging residues), or other types of plant or plant-derived waste, may also be used as plant material. Particularly exemplary plant materials include corn fiber, corn stover, and sugarcane bagasse, in addition to "target" energy crops such as switchgrass, miscanthus, and algae. Short-rotation forest products, such as energy crops, include alder, ash, Anthracnose beech, birch, eucalyptus, poplar, willow, paper mulberry, Australian blackwood, sycamore, and various oak trees. Other examples of suitable biomass include vegetable oils, carbohydrates (e.g., sugars), organic waste materials, such as waste paper, structures, demolition waste, digested sludge, and biosludge. Accordingly, exemplary carbonaceous feeds include or comprise any of these types of biomass. Specific carbonaceous feeds containing biomass include municipal solid waste (MSW) or MSW-derived products, such as refuse-derived fuel (RDF). The carbonaceous feed may include a combination of petroleum-derived materials and renewable materials, including those mentioned above.

[0046] In the gasifier 100 (or, more specifically, the gasification reactor of the gasifier), the carbonaceous feed 10 is partially oxidized in the presence of an oxygen-containing gasifier feed 5, typically in an amount limited to provide only 20-70% of the oxygen required for complete combustion. The oxygen-containing gasifier feed typically includes other oxygenated gaseous components, including HO and / or CO, which may act as oxidizers for the carbonaceous feed 10. The oxygen-containing gasifier feed 5 may refer to all gases being fed to or added to the gasifier 100, regardless of whether they are combined upstream of or within the gasifier. For example, the oxygen-containing gasifier feed 5 may include at least a portion of the regeneration effluent (e.g., the illustrated cooled regeneration effluent 25) and / or at least a portion of the fresh gasifier feed (e.g., the illustrated second portion 20b of the fresh gasifier feed 20). Within the gasifier 100, the carbonaceous feed 10 is contacted with the oxygen-containing gasifier feed 5 under gasification conditions to provide a gasifier effluent. One or more reactors of the gasifier 100 (e.g., operating in series or parallel) may be operated under gasification conditions present in such reactor(s), which generally include temperatures from about 500°C (932°F) to about 1000°C (1832°F), and typically from about 750°C (1382°F) to about 950°C (1742°F). Other gasifier conditions may include atmospheric pressure or elevated temperatures, for example, absolute pressures generally from about 0.1 megapascals (MPa) (14.5 psi) to about 10 MPa (1450 psi), and typically from about 1 MPa (145 psi) to about 3 MPa (435 psi).

[0047] Other gasification reactor configurations include countercurrent fixed bed ("updraft"), cocurrent fixed bed ("downdraft"), and entrained plasma. Various solid catalysts may be used with different activities for one or more desired functions during gasification, such as tar reduction, increased H yield, and / or reduced CO yield. Limestone may be added to the gasification reactor to promote tar reduction, for example, by pyrolysis. Various catalyst materials may be used in the gasification reactor, including dolomite, supported nickel, alkali metals, and solid particles of alkali metal compounds, such as alkali metal carbonates, bicarbonates, and hydroxides. Gasifiers are often operated with a gasification reactor having a fluidized bed of particles of carbonaceous feed (and, optionally, particles of solid catalyst), with the oxygen-containing gasifier feed and, optionally, a separate fluidized H2O- and / or CO2-containing feed fed upward through the particle bed. Exemplary types of fluidized beds include bubbling fluidized beds and entrained fluidized beds.

[0048] In addition to gasifier effluent tar, this effluent contains carbon present in the carbonaceous feed, as well as CO, CO, and methane (CH), which are typically derived from H and / or H O and both, along with trace concentrations of other constituents, as described below. According to the illustrated embodiment, raw gasifier effluent 12 can be obtained as gasifier effluent directly from the gasifier 100, prior to any processing steps described herein.

[0049] The syngas product 40 may contain H and CO in various amounts (concentrations), preferably in total amounts greater than about 20 mol % (e.g., about 25 mol % to about 95 mol %), greater than about 50 mol % (e.g., about 50 mol % to about 90 mol %), or greater than about 65 mol % (e.g., about 65 mol % to about 85 mol %). These total amounts may be on a water-free basis. With any such total amount (concentration), the H:CO of the syngas product may be suitable for use in the downstream reactions described above. These include conversion to higher molecular weight hydrocarbons and / or alcohols of various carbon numbers via Fischer-Tropsch conversion, or to RNG via catalytic methanation, which increases the methane content in the resulting RNG stream. For example, the H:CO molar ratio of the syngas product 40, optionally after a water-gas shift (WGS) reaction and / or hydrogenation to increase its hydrogen content, may be from about 0.5 to about 2.5, e.g., from about 1.0 to about 2.0. Independently or in combination with the above exemplary amounts (concentrations) of H and CO and / or the above exemplary H:CO molar ratios, the synthesis gas product may include, for example, CO in an amount of at least about 2 mol % (e.g., from about 2 mol % to about 30 mol %), at least about 5 mol % (e.g., from about 5 mol % to about 25 mol %), or at least about 10 mol % (e.g., from about 10 mol % to about 20 mol %). Independently or in combination with the above exemplary amounts (concentrations) of H, CO, and CO and / or the above exemplary H:CO molar ratios, the synthesis gas product may include, for example, CH in an amount of at least about 0.5 mol % (e.g., from about 0.5 mol % to about 15 mol %), at least about 1 mol % (e.g., from about 1 mol % to about 10 mol %), or at least about 2 mol % (e.g., from about 2 mol % to about 8 mol %). These non-condensable gases H, CO, CO, and CH, along with any water vapor (HO), may comprise substantially all of the composition of the syngas product, i.e., these non-condensable gases, and any water, may be present in the syngas product 40 in a total amount of at least about 90 mol %, at least about 95 mol %, or even at least about 99 mol %.The balance of the synthesis gas product may be all, or substantially all, non-reactive and / or inert gases, such as N2 and / or Ar.

[0050] With respect to any of these properties of the synthesis gas product 40, considering the above H, CO, CO, and / or CH content and / or the above exemplary H:CO molar ratios, these may likewise apply, at least on a tar-free basis, to the upstream compositions of the gasifier effluent 30 and / or the cleaned cooled gasifier effluent 16, the cleaned gasifier effluent 14, and / or the raw gasifier effluent 12. In this regard, it should be understood that the operations performed by (i) a centrifuge (e.g., a cyclone) 105 on the raw gasifier effluent 12 to provide cleaned gasifier effluent 14, (ii) a gasifier effluent cooler 110 on the cleaned gasifier effluent 14 to provide cleaned cooled gasifier effluent 16, and (iii) filtration 115 on the cleaned cooled gasifier effluent 16 to provide gasifier effluent 30 (e.g., "cleaned, cooled, filtered gasifier effluent" according to certain embodiments) are optional operations, whereby one or more of these may be omitted depending on the particular processing objectives (e.g., depending on the particular carbonaceous feed 10 being gasified). Thus, to the extent that the processes described herein involve adsorbing gasifier effluent tar from gasifier effluent 30 using a tar adsorber 200, or alternatively converting this tar using a tar conversion reactor 200, any one of raw gasifier effluent 12, cleaned gasifier effluent 14, or cleaned cooled gasifier effluent 16 can likewise be input (used as a feed) to the tar adsorber 200 or the tar conversion reactor 200.

[0051] Aside from the context of the above-described H, CO, CO, and / or CH content and / or exemplary H:CO molar ratios applied to the syngas product 40 and / or gasifier effluent 30, in addition to any one or more of the raw gasifier effluent 12, the cleaned gasifier effluent 14, and / or the cleaned cooled gasifier effluent 16, these streams may further include various amounts of contaminants, such as sulfur compounds (e.g., HS and / or COS), nitrogen compounds (e.g., NH), and solids (e.g., as solid particulates). However, in general, treatment steps may be used to reduce the amount of such contaminants in the gasifier effluent 30 compared to the raw gasifier effluent 12. For example, the gasifier effluent 30 may be obtained after one or more steps that remove solids, such as those originally present in the gasifier effluent 12 directly from the gasifier 100. In certain embodiments, these one or more steps may include a centrifugation step, such as using a centrifuge (e.g., a cyclone) 105 to remove relatively coarse particles, and a filtration step, such as using a filter 115 to remove relatively fine particles. In this case, the centrifugation and filtration steps may be performed upstream and downstream, respectively, of a gasifier effluent cooling step, such as using a gasifier effluent cooler 110 or other system or device to cool the gasifier effluent and / or recover heat from the gasifier effluent (e.g., to generate high-pressure steam).

[0052] Either or both of the centrifuge 105 and the filter 115 may, in alternative embodiments, be any suitable gas filtering and / or scrubbing operation for removing solid particles (particulates) from the gasifier effluent. In the case of biomass gasification, these solid particles may include charcoal, soot, and ash, any of which may generally contain alkali metals such as sodium. Corrosive and / or harmful species, such as chlorides, arsenic, and / or mercury, may also be included in such particulates. For example, high-temperature filtration using a bundle of metal or ceramic filters may generally be sufficient to reduce the particulate content in the gasifier effluent upstream of (before) the tar absorber / tar conversion reactor 200 to less than 1 ppm by weight, and in some cases, less than 0.1 ppm by weight, facilitating its more efficient operation. After the centrifuge 105, filter 115, and / or any such gas filtration and / or washing operations downstream, and before the tar adsorption / tar conversion reactor 200, an additional washing operation can be used to further reduce the tar and overall hydrocarbon content of the raw gasifier effluent 12 by contacting it with a solid "abrasive" material, such as a carbon bed, thereby providing more complete removal of benzene, naphthalene, toluene, phenol, and other condensable species that might otherwise be harmful to downstream operations, such as by deposition on equipment.

[0053] It should also be understood that the above-described processing steps performed on raw gasifier effluent 12 to obtain gasifier effluent 30 for subsequent contact with the solid sorbent or solid catalyst described herein are optional, but are not exhaustive. Other processing steps practiced in the art may also be used to obtain gasifier effluent 30, such as to remove sulfur compounds (e.g., using a suitable guard bed such as an iron- or zinc-oxide-containing material), to otherwise purify (e.g., scrub to remove acid gases such as CO), and / or to adjust the H:CO molar ratio (e.g., using a water-gas shift (WGS) reactor or hydrogen addition).

[0054] In the case of a treatment step for removing sulfur compounds, the sulfur compounds may more specifically include H2S, COS, and / or SO2 contained in the raw gasifier effluent 12. Such compounds, resulting from the presence of trace amounts of sulfur in a carbonaceous feed, including biomass, may be harmful to (e.g., poison) the catalyst used in the tar conversion reactor 200 and / or the catalyst used in the conversion of the synthesis gas product to the value-added products (e.g., higher molecular weight hydrocarbons and / or alcohols) mentioned above. Harm may occur, for example, through the formation of metal sulfide compounds, such as nickel sulfide, at catalytically active metal sites, such as nickel sites, of the catalyst. In accordance with a specific treatment step for removing sulfur compounds, the sulfur removal operation may include contacting the gasifier effluent, at any stage downstream of the gasifier 100 and upstream of the tar absorber / tar conversion reactor 200, with a suitable guard bed to obtain a gasifier effluent 30 that is substantially free of sulfur, for example, having a total sulfur content of less than 1 ppm by weight, e.g., less than 0.1 ppm by weight. Suitable guard bed materials include those used in water treatment, such as iron-containing adsorbent (iron "sponge") materials, and / or zinc oxide.

[0055] In another aspect, for purification processing, an acid gas removal operation may be performed on the gasifier effluent at any stage, for example, downstream of the gasifier 100 and upstream of the tar absorber / tar conversion reactor 200, to reduce the concentration of CO and / or other acid gases (e.g., H2S). (登録商標) (Polyethylene glycol dimethyl ether), Rectisol (登録商標)One or more steps of contacting the raw gasifier effluent with a physical solvent, such as ethanolamine, diethanolamine, methyldiethanolamine, diisopropylamine, or diglycolamine, or in other cases, a solution of methanol, potassium carbonate, or a sodium salt of an amino acid, may also be employed to remove at least a portion of the acid gases originally present in the raw gasifier effluent 12. After the acid gas removal operation and upstream of the tar absorber / tar conversion reactor 200, the gasifier effluent may generally have a CO2 concentration of about 2 mol% to about 40 mol%, and typically about 5 mol% to about 20 mol%, and may have a total sulfur concentration of less than about 0.1 mol-ppm. Alternatively, in the case of a treatment step for purification, operations to remove water and water-soluble contaminants may be performed on the gasifier effluent at any stage downstream of the gasifier 100 and upstream of the tar absorber / tar conversion reactor 200. For example, a wet scrubbing operation involving contacting the gasifier effluent with water (e.g., by co-current or counter-current contacting in a trayed column) can be effective in removing chlorides (e.g., in the form of HCl) and ammonia, as well as fine solid particles (e.g., charcoal and ash).

[0056] In the case of a treatment step to adjust the H:CO molar ratio, a specific example is a sour shift operation, which may be used to conduct the WGS reaction in the presence of sulfur compounds, thereby increasing the concentration of H (or the H:CO molar ratio) compared to that initially present in the raw gasifier effluent as obtained from the gasifier. This operation may include one or more WGS reactors (e.g., operated in series or parallel) with a suitable catalyst, such as a cobalt-molybdenum catalyst, that is resistant to deactivation in the presence of H2S and / or COS. Other catalysts for this purpose include copper- and / or zinc-containing catalysts, such as Cu-Zn-Al, chromium-containing catalysts, catalysts based on iron oxide, zinc ferrite, magnetite, chromium oxide, and any combination thereof (e.g., Fe2O3-Cr2O3 catalysts). Conditions for the catalytic WGS reaction may include temperatures from about 150°C (302°F) to about 400°C (752°F).

[0057] The optional inclusion of these specifically described and other process steps within the scope of the present invention depends on the specific processing objectives (e.g., the specific carbonaceous feed 10 being gasified). Generally, such processing steps may be performed at various stages of the overall process (e.g., upstream or downstream of the tar absorber / tar conversion reactor 200) necessary to achieve those objectives. For example, (i) operations to remove water and water-soluble contaminants (e.g., wet scrubbing operations) and / or (ii) processing steps to adjust the H:CO molar ratio (e.g., sour shift operations) may be performed downstream of the tar absorber / tar conversion reactor. Certain processing steps (e.g., centrifugation steps) may also be performed in situ within the gasifier 100 (e.g., using internal cyclones to remove solid particles located in the headspace of the fluidized particle bed).

[0058] Regardless of any processing steps used to obtain the gasifier effluent, certain aspects of the present invention relate to removing tars (gasifier effluent tar) from the effluent by adsorption or catalytic conversion. For example, an exemplary adsorption process may include contacting at least a portion of the gasifier effluent with at least a first bed of solid sorbent (contained in a tar adsorber) under tar adsorption conditions in a tar adsorber 200 to provide a tar adsorber effluent 32 having a reduced amount of tar (e.g., compared to the amount in the gasifier effluent). The tar adsorption conditions may include a temperature of from about 400°C (752°F) to about 600°C (1112°C). An exemplary catalytic conversion process may include contacting at least a portion of the gasifier effluent with at least a first bed of solid catalyst (contained in a tar conversion reactor) under tar conversion conditions in a tar conversion reactor 200 to provide a reactor effluent 32 having a reduced amount of tar (e.g., compared to the amount in the gasifier effluent). Depending on the activity of the solid catalyst, tar conversion conditions may include temperatures that are generally higher than those described above for tar adsorption conditions and may also be higher than those used in a gasifier. For example, these temperatures may, in some cases, be greater than 1000°C (e.g., from about 1000°C (1832°F) to about 1500°C (2732°F), e.g., from about 1000°C (1832°F) to about 1250°C (2282°F). Adsorption of tar carried out in tar adsorber 200 does not preclude the possibility of at least some conversion of the tar. Similarly, conversion of tar carried out in tar conversion reactor 200 does not preclude the possibility of at least some adsorption of tar (e.g., by reforming to obtain additional components of the syngas) and / or at least some conversion of methane.

[0059] Thus, it can be appreciated that in preferred embodiments, the tar adsorber can advantageously operate without external heating of the vessel. That is, the heat requirements of the tar adsorber 200 may be obtained entirely from heat present in either the raw gasifier effluent 12, the cleaned gasifier effluent 14, the cleaned cooled gasifier effluent 16, or the gasifier effluent 30 (e.g., the "cleaned cooled filtered gasifier effluent," according to certain embodiments). This can be contrasted with the operation of a tar conversion reactor, which requires external heating, particularly when operating above the temperature of the gasifier 100. However, regardless of whether a solid adsorbent is used to make the vessel 200 a tar adsorber or a solid catalyst is used to make the vessel a tar conversion reactor, in preferred embodiments, process temperatures are maintained to avoid condensation of any gasifier effluent tar within and upstream of the vessel. For example, the gasifier effluent 30, including any portion 30a thereof introduced into the tar absorber or tar conversion reactor, may be maintained at a temperature above the condensation temperature within the vessel, as well as from the gasifier 100 to the vessel (e.g., in the process line or piping from the gasifier outlet to the inlet of the tar absorber 200 or tar conversion reactor 200). This condensation temperature may correspond to the temperature at which the gasifier effluent tar (e.g., present in any of 12, 14, 16, or 30), or the highest boiling point component(s) of this tar, first condenses, and thus may also be referred to as the tar dew point. According to certain embodiments, the tar absorber or tar conversion reactor, and / or process lines or piping from the gasifier outlet to the inlet of the vessel, and optionally any equipment, may be maintained at a temperature at least about 10°C (18°F), at least about 25°C (45°F), or at least about 50°C (90°F) above the condensation temperature or tar dew point of any of the gasifier effluent 12, cleaned effluent 14, and / or cleaned cooled gasifier effluent 16.Armed with knowledge of the present disclosure, one skilled in the art will understand that the condensation temperature or tar dew point can be determined statistically based on the amount or concentration of CO, CO2, H2, and / or tar present in a given composition, optionally in combination with simulation tools that provide estimates of such temperatures. In terms of specific temperatures, according to certain embodiments, the tar absorber or tar conversion reactor, and / or process lines or piping from the gasifier outlet to the vessel inlet, and optionally any equipment, can be maintained at a temperature of at least about 300°C (572°F), at least about 400°C (752°F), or at least about 450°C (842°F).

[0060] Another feature associated with using a tar adsorber, as compared to a tar conversion reactor, is that in the previous operation, the tar adsorber effluent 32 may be substantially free of tar conversion products, in the same manner as the cooled tar adsorber effluent 34 (obtained after cooling) and the cooled washed tar adsorber effluent 40 (e.g., the synthesis gas product obtained after cooling and removal). That is, in exemplary embodiments, the tar adsorber effluent may be completely or substantially completely free of CO, CO, and / or H resulting from the conversion of the gasifier effluent tar. For example, the effluent may contain CO, CO, and / or H in amounts representing less than about 10%, less than about 5%, or less than about 1% of the conversion of the gasifier effluent tar. In some embodiments, the lack of conversion may indicate no or substantially no increase, or, to the extent possible, no or substantially no change, in the amount(s) or concentration(s) of any one or more of these components throughout the tar adsorber 200 (e.g., in the tar adsorber effluent 32 relative to the gasifier effluent 30). For example, any change in the tar adsorber effluent 32 relative to the gasifier effluent 30 may be solely due to tar adsorption, such that tar concentrations may be lower in the tar adsorber effluent 32 compared to the gasifier effluent 30 (e.g., may be absent or substantially absent in the gasifier effluent 30).

[0061] A further feature associated with using a tar adsorber as compared to a tar conversion reactor is that the operation of the former may advantageously avoid the administration of additional steam and / or oxygen reactants. In an exemplary embodiment of the tar adsorption process, no supplemental sources of steam and / or oxygen are added to the tar adsorber 200 or upstream of the tar adsorber 200, e.g., to the gasifier effluent 30, or more broadly, to any point downstream of the gasifier 100 up to the tar adsorber 200, e.g., from the raw gasifier effluent 12 up to the tar adsorber 200.

[0062] According to certain embodiments, gasifier effluent 30, including any portion 30a thereof introduced into a tar adsorber or tar conversion reactor (depending on whether a solid sorbent or solid catalyst is utilized), may contain tar in an amount of about 0.01% to about 5% by weight, e.g., about 0.1% to about 3% by weight, or about 0.5% to about 2% by weight. Whether a solid sorbent is utilized such that vessel 200 is a tar adsorber or a solid catalyst is utilized such that vessel 200 is a tar conversion reactor, tar adsorption or tar conversion can be effective to substantially or completely remove the gasifier effluent tar. For example, tar adsorber effluent or reactor effluent exiting a tar adsorber or tar conversion reactor, respectively, may contain less than about 0.5%, less than about 0.1%, or less than about 0.01% by weight of tar. Exemplary levels of tar adsorption or tar conversion measured across the tar adsorber or tar conversion reactor may be at least about 90%, at least about 95%, or even at least about 99%, resulting in a tar adsorber or reactor effluent that may be substantially or completely free of tar.

[0063] Armed with knowledge of the present disclosure, one skilled in the art can determine the presence of tar conversion products, as well as the percentage of gasifier effluent tar that is adsorbed or converted, based on analysis of the compositions upstream and downstream of the tar adsorber 200 or tar conversion reactor, including the amount or concentration of CO, CO, H, and / or tar present in those compositions.

[0064] Whether an adsorption process is used to provide the tar absorber effluent 32 or a catalytic conversion process is used to provide the reactor effluent 32, the various processing steps described above for obtaining the gasifier effluent 30 from the raw gasifier effluent 12 may also optionally be used to recover the syngas product 40 from the tar absorber effluent or reactor effluent. For example, such processing steps may be used to reduce the amount of contaminants (e.g., solids) described above, cool and / or recover heat, remove sulfur compounds, otherwise purify, and / or adjust the H:CO molar ratio. In this regard, it may be understood that the tar absorber effluent / reactor effluent 32 may be referred to as the raw syngas product 32, which may be equivalent to the syngas product 40 (i) if a processing step is performed, or (ii) in the absence of a processing step. For example, the syngas product 40 may be recovered after one or more steps of cooling and / or washing the tar absorber effluent / reactor effluent 32. In certain embodiments, a cooling step, such as using a syngas product cooler 120 or other system or device to cool and / or recover heat from (to produce high-pressure steam) the tar adsorber / reactor effluent 32, may be used to provide cooled syngas product 34. Alternatively, or in combination, a removal step, such as using a syngas remover 125 to remove acid gases, such as CO, from the raw syngas product 32 or the cooled syngas product 34 to provide a cooled, cleaned syngas product 40.

[0065] In the case of a tar adsorber 200 containing a first bed of solid sorbent according to an exemplary adsorption process, or a tar conversion reactor 200 containing a first bed of solid catalyst according to an exemplary catalytic conversion process, such a process may further include replacing at least a portion of such first bed based on (or depending on) an indication of sufficient utilization of either the solid sorbent or the solid catalyst. Such an indication may optionally be the operating time in terms of one or more process parameters, such as those related to the severity exerted by the solid sorbent or the solid catalyst. These parameters may include the type of carbonaceous feed, the gasification conditions, the amount of tar in the gasifier effluent, the temperature used for tar adsorption or tar conversion, or any combination of these parameters. The indication of sufficient utilization may also be the pressure drop across the tar adsorber 200 or the tar conversion reactor 200, which may correspond to the pressure drop across the first bed of solid sorbent or the first bed of solid catalyst, respectively, and may further correspond to the amount of adsorbed tar and / or catalytic coke present in the first bed material. An indicator of sufficient utilization may also be, for example, (i) a tar breakthrough, such as tar observed or detected downstream of the tar absorber 200 or the tar conversion reactor 200, as a condensate in a process unit or another unit, or (ii) by analysis (e.g., of the raw syngas product 32, the cooled syngas product 34, or the syngas product 40). An indicator of sufficient utilization may also be, for example, a chlorine (e.g., in the form of HCl) or ammonia breakthrough detected by analysis downstream of the tar absorber 200 or the tar conversion reactor 200. Any one or more of such indicators of sufficient utilization may have an associated threshold value that, when reached, forms the basis for replacing at least a portion of the first bed. For example, an indicator of sufficient utilization may be (i) an operating time reaching a threshold time of operation, (ii) a pressure drop reaching a threshold pressure drop, or (iii) a tar breakthrough reaching a threshold tar breakthrough.Combinations of such indicators may also be used to form the basis for replacing at least a portion of the first bed, such as, for example, a combination of (i), (ii) and / or (iii) in certain cases where either (i), (ii) or (iii) occurs first, or where either (i), (ii) or (iii) occurs last.

[0066] Regarding replacing at least a portion of the first bed of solid adsorbent or solid catalyst based on the indication of sufficient utilization, this may, according to certain embodiments, include replacing the entire bed or replacing the entire vessel containing this bed (e.g., a tar adsorber or a tar conversion reactor). The "replacing" step may include physical replacement of all or a portion of the first bed of solid adsorbent contained in the tar adsorber or all or a portion of the first bed of solid catalyst contained in the tar conversion reactor, as the case may be. According to certain embodiments, at least a portion of the first bed of solid adsorbent contained in the tar adsorber or at least a portion of the first bed of solid catalyst contained in the tar conversion reactor may be replaced with at least a portion of a second bed of solid adsorbent or at least a portion of a second bed of solid catalyst, respectively, after regeneration of the second bed, for example, as described below. Physical replacement of the solid adsorbent or solid catalyst may accompany "on-stream" adsorption or catalytic operations during normal shutdown or shutdown periods as required to implement the requirements. However, as a practical alternative, the "replacing" step may not require a termination or shutdown period, such as in the case of the present step, which involves rerouting the process flow.

[0067] For example, the figure shows a valve arrangement that provides a "swing bed" configuration that allows the position of the vessels 200, 300 to be changed in terms of the overall process flow and equipment. Specifically, the position, and therefore function, of a first "on-duty" tar adsorber 200 containing a first bed of solid sorbent, or alternatively, a first "on-duty" tar conversion reactor 200 containing a first bed of solid catalyst, may be switched to the position, and therefore function, of a second "regenerated" tar adsorber 300 containing a second bed of solid sorbent, or alternatively, a second "regenerated" tar conversion reactor 300 containing a second bed of solid catalyst. The valve arrangement includes a first gasifier effluent inlet valve 50, a second gasifier effluent inlet valve 55, a first fresh gasifier feed inlet valve 60, and a second fresh gasifier feed inlet valve 65. The first and second gasifier effluent inlet valves 50, 55 may be configured to flow the gasifier effluent 30 to either vessel 200 or 300 for use as an operating tar adsorber or an operating tar conversion reactor, and may further be configured to flow the corresponding first portion 30a and / or second portion 30b of the gasifier effluent 30 to these corresponding vessels. Similarly, the first and second fresh gasifier feed inlet valves 60, 65 may be configured to flow the fresh gasifier feed 20 to either vessel 300 or 200 for use as a regenerated tar adsorber or a regenerated tar conversion reactor. These valves may also be further configured to flow the corresponding first portion 20a and / or third portion 20c of the fresh gasifier feed 20 to these corresponding vessels, optionally in combination with the regenerated effluent 22 or cooled regenerated effluent 25 of the oxygen-containing gasifier feed 5, of which the second portion 20b is a component.

[0068] For example, during operation with vessel 200 being either an operating tar adsorber or an operating tar conversion reactor, and with vessel 300 being either a regenerative tar adsorber or a regenerative tar conversion reactor, first gasifier inlet valve 50 may be opened and second gas inlet valve 55 may be closed to allow all of gasifier effluent 30 to enter vessel 200 and contact the first bed of solid sorbent or the first bed of solid catalyst contained therein. Additionally, second fresh gasifier feed inlet valve 65 may be closed and first fresh gasifier feed inlet valve 60 may be opened to the extent that first portion 20a of fresh gasifier feed 20 may be entered into vessel 300 and contact the second bed of solid sorbent or the second bed of solid catalyst contained therein. The first portion 20a is sufficient to regenerate the second bed by contacting it under regenerating conditions to provide a regenerated effluent 22 initially comprising CO, CO2, HO, and / or H2 resulting from the oxidation, pyrolysis, and / or reformation of adsorbed tar and / or catalytic coke present on the surface or in the pores of the second bed of solid adsorbent or solid catalyst, depending on whether the process utilizes tar or tar conversion. The regenerated effluent 22 may then be cooled in an optional cooling step, such as when a regenerated effluent cooler 130 or other system or device is used to cool the regenerated effluent 22 and / or recover heat from the regenerated effluent 22 (e.g., to generate high-pressure steam), to provide a cooled regenerated effluent 25.

[0069] The relative amounts of the first portion 20a and second portion 20b of fresh gasifier feed 20 used to regenerate the second bed contained in vessel 300 (as a component of oxygen-containing gasifier feed 5) and to feed directly to gasifier 100, respectively, can vary depending on several operating parameters and may be adjusted depending on measurements of such parameters. These parameters include the oxygen concentration of the fresh gasifier feed 20 and the oxygen concentration of the oxygen-containing gasifier feed 5, with increasing oxygen concentration in the fresh gasifier feed 20 and / or the oxygen-containing gasifier feed resulting in a greater amount of the first portion 20a being used for regeneration compared to the second portion. According to other embodiments, the entire fresh gasifier feed 20 may be introduced into vessel 300 as first portion 20a, with oxygen breakthrough in the regeneration effluent or cooled regeneration effluent providing the overall oxygen content of the oxygen-containing gasifier feed 5. In any event, the fresh gasifier feed 20 may contain sufficient steam and oxygen to oxidize, pyrolyze, and / or reform the adsorbed tar and / or catalytic coke under regeneration conditions used over the regeneration period in vessel 300 commensurate with the operating time that vessel 200 is used as an operating tar adsorber or an operating tar conversion reactor.

[0070] Generally, the fresh gasifier feed 20 may contain HO and O, and optionally CO, in a total concentration of at least about 90 mol%, at least about 95 mol%, or at least about 99 mol%. While the propensity of these components to oxidize varies greatly, all of these components may function as oxidizers for adsorbed tar and / or catalytic coke during the regeneration of spent sorbent. Exemplary regeneration conditions used in the second "regenerative tar adsorber" 300 or second "regenerative tar conversion reactor" 300 may include temperatures from about 400°C (752°F) to about 1000°C (1832°F), e.g., from about 550°C (1022°F) to about 850°C (1562°F). The regeneration period may generally be sufficient to achieve a content of adsorbed tar and / or catalytic coke remaining on the regenerated solid adsorbent or regenerated solid catalyst of less than about 1 wt.%, less than about 0.5 wt.%, or even less than about 0.1 wt.%.

[0071] Advantageously, according to the illustrated embodiment, in which the oxygen-containing gasifier feed 5 comprises (i) the second portion 20b of the fresh gasifier feed 20, and / or (ii) at least a portion of the regeneration effluent 22 or at least a portion of the cooled regeneration effluent 25, the feed to the overall gasification process can be utilized in an efficient and flexible manner, and the CO2 produced by regeneration can be retained in the process rather than being released into the atmosphere.

[0072] After a sufficient period of utilization (or other indicators) by vessel 200, which is either an operating tar adsorber or an operating tar conversion reactor, and by vessel 300, which is either a regenerated tar adsorber or a regenerated tar conversion reactor, first gasifier inlet valve 50 may be closed and second gas inlet valve 55 may be opened to allow all of gasifier effluent 30 to enter vessel 300 and contact the second bed of regenerated solid sorbent or the second bed of regenerated solid catalyst, as the case may be. In addition, second fresh gasifier feed inlet valve 65 may be opened to an extent to allow a third portion 20c of fresh gasifier feed 20 to enter vessel 200 and contact the first bed of solid sorbent or the first bed of solid catalyst, as the case may be. The third portion 20c is sufficient to regenerate the first bed in the manner described above for regenerating the second bed of vessel 300. It can be understood that with this arrangement of valves, one of the vessels 200, 300 may be effectively "removed" from a given operation, such as a tar adsorption operation or a regeneration operation, and "replaced" with the other vessel in terms of the rerouted process flow. In this manner, the vessels, and the corresponding beds of solid adsorbent or solid catalyst contained therein, may be alternated between tar adsorption and solid adsorbent regeneration, or alternatively, between tar conversion and solid catalyst regeneration, over extended periods of operation during which at least one of the vessels 200, 300 functions as an "on-duty" tar adsorber or "on-duty" tar conversion reactor. Complete rerouting of the process flow to achieve the objective of alternating between tar adsorption and regeneration, or between tar conversion and regeneration, may include using additional valves, such as first and second product outlet valves 70, 80 and first and second regeneration outlet valves 75, 85, to route the outlets from vessels 200, 300 to either the regeneration effluent as a component of the oxygen-containing gasifier feed 5 or to the syngas product.

[0073] In some embodiments, valves 50, 55 may be combined into a single valve, such as a multi-port valve. Multiple valves or a single valve may be used to divert various proportions of gasifier effluent 30 in first portion 30a and second portion 30b to vessels 200, 300. Similarly, valves 60, 65 may be combined into a single valve, such as a multi-port valve. Multiple valves or a single valve may be used to divert various proportions of fresh gasifier feed 20 in first portion 20a, second portion 20b, and third portion 20c to vessels 300, 100, and 200, respectively. Similarly, valves 70, 80 may be combined into a single valve (e.g., a multi-port valve) and / or valves 75, 85 may be combined into a single valve (e.g., a multi-port valve). Multiple valves 70, 80 or a single valve and / or multiple valves 75, 85 or a single valve may be used to divert various proportions of the tar adsorber / reactor effluent 32 and / or regeneration effluent 22 to the gasifier feed 5 and syngas product 40.

[0074] Collectively, the arrangement of these valves 50, 55, 60, 65, 70, 75, 80, 85 allows substantial flexibility in the manner in which the streams of (a) gasifier effluent 30 and portions thereof 30a, 30b, and / or (b) fresh gasifier feed 20 and portions thereof 20a, 20b, 20c can be routed to either the operating tar absorber / tar conversion reactor or the tar absorber / regenerated tar conversion reactor. This arrangement further allows substantial flexibility in the manner in which the streams of (c) effluent from the tar absorber / tar conversion reactor and / or (d) effluent from the regenerated tar absorber / regenerated tar conversion reactor can be routed to either the regenerated effluent as a component of the oxygen-containing gasifier feed 5 or the syngas product 40.

[0075] In the case of managing stream (a), the relative amounts of first portion 30a and second portion 30b used to contact the first bed (e.g., containing fresh adsorbent, fresh catalyst, regenerated adsorbent, or regenerated catalyst) in the “on-stream” tar adsorber / tar conversion reactor 200 and the second bed (e.g., containing spent adsorbent or spent catalyst) in the “regenerated” tar adsorber / tar conversion reactor 300 can be varied based on several operating parameters. These parameters include the H:CO molar ratio of the gasifier effluent 30 and / or the CO concentration of the gasifier effluent 30. In the case of the H:CO molar ratio, portions 30a, 30b of the gasifier effluent 30 can be varied depending on whether this ratio is suitable or desirable in the downstream reactions described above, with a relatively large amount of first portion 30a being diverted to the “on-stream” tar adsorber / tar conversion reactor 200 when the H:CO molar ratio reaches a target value. In the case of CO2 concentration, portions 30a, 30b of gasifier effluent 30 may be varied to retain CO2 in the process, and when the CO2 concentration exceeds a target value, a relatively larger second portion 30b is diverted to the "regenerative" tar adsorber / tar conversion reactor 300. Thus, according to an exemplary embodiment, the process may include increasing the proportion of gasifier effluent contacting the first bed and / or decreasing the proportion of gasifier effluent contacting the second bed in response to the measured H2:CO molar ratio of the gasifier effluent reaching a target H2:CO molar ratio (e.g., any target value in the range of 0.5 to 2.5, e.g., any target value in the range of 1 to 2, e.g., a target value of 1). A measured H:CO molar ratio that "attains" the target ratio may be represented by a first measurement that deviates from the target ratio (e.g., by more than 5%, by more than 10%, or by more than 25%) and a second, subsequent measurement that meets the target ratio (e.g., within ±5%, within ±10%, or within ±25%, respectively).Alternatively, or in combination, the process may include increasing the proportion of gasifier effluent contacting the second bed and / or decreasing the proportion of gasifier effluent contacting the first bed in response to a measured CO2 concentration of the gasifier effluent that exceeds a target CO2 concentration (e.g., any target value in the range of 2 mol% to 30 mol%, such as any target value in the range of 5 mol% to 25 mol%, such as a target value of 10 mol%).

[0076] As noted above, in the case of managing stream (b), the relative amounts of the first and second portions 20a and 20b of fresh gasifier feed 20 used to regenerate the second bed contained in vessel 300 (as a component of oxygen-containing gasifier feed 5) and to feed directly to gasifier 100, respectively, can vary based on several operating parameters and may be adjusted in response to measurements of such parameters. These parameters include the oxygen concentration of the fresh gasifier feed 20 and the oxygen concentration of the oxygen-containing gasifier feed 5, with increasing oxygen concentration in the fresh gasifier feed 20 and / or the oxygen-containing gasifier feed in one direction resulting in a larger amount of the first portion 20a being used for regeneration relative to the second portion, or alternatively, a larger total amount of the first and third portions 20a, 20c. Thus, according to an exemplary embodiment, the process may include, depending on the measured CO concentration of the fresh gasifier feed or the measured O concentration of the oxygen-containing gasifier feed, corresponding to a percentage of combustion of the carbonaceous feed above a target percentage of combustion (e.g., any target value in the range of 20%-70%, e.g., any target value in the range of 30%-50%, e.g., a target value of 40 mol%), increasing the percentage of fresh gasifier feed for contacting the second bed, and / or decreasing the percentage of fresh gasifier feed for contacting the carbonaceous feed. Alternatively, the percentage of fresh gasifier feed for contacting both the first bed and the second bed in combination may be increased.

[0077] In the case of management of stream (c), the relative amount of tar absorber effluent / tar conversion reactor 32 to provide a greater or lesser contribution to either oxygen-containing gasifier feed 5 or syngas product 40 (as a component thereof) can be varied depending on several operational parameters. These parameters include the H:CO molar ratio of the effluent 32 and / or the CO concentration of the effluent 32. In the case of H:CO molar ratio, the amount of this effluent can be varied depending on whether this ratio is suitable or favorable in the reactions described above downstream, with a relatively greater amount being diverted to syngas product 40 when the H:CO molar ratio reaches a target value. In the case of CO concentration, the amount can be varied to keep CO in the process, with a relatively greater amount being diverted to oxygen-containing gasifier feed 5 when the CO concentration is above a target value. Thus, according to an exemplary embodiment, the process may include increasing the proportion of the tar adsorber effluent or the tar conversion reactor effluent provided as a component of the synthesis gas product and / or decreasing the proportion of the effluent provided as a component of the oxygen-containing gasifier feed in response to a measured H:CO molar ratio of the tar adsorber effluent or the tar conversion reactor effluent reaching a target H:CO molar ratio (e.g., any target value in the range of 0.5 to 2.5, e.g., any target value in the range of 1 to 2, e.g., a target value of 1). A measured H:CO molar ratio that "reaches" the target ratio may be indicated as described above for management of stream (a). Alternatively, or in combination, the process may include increasing the proportion of tar adsorber effluent or tar conversion reactor effluent that exceeds a target CO concentration (e.g., any target value in the range of 2 mol% to 30 mol%, e.g., any target value in the range of 5 mol% to 25 mol%, e.g., a target value of 10 mol%) that is provided as a component of the oxygen-containing gasifier feed and / or decreasing the proportion of that effluent that is provided as a component of the synthesis gas product in response to the measured CO concentration.

[0078] In the case of management of stream (d), the relative amount of regeneration effluent 22 to provide a greater or lesser contribution to the oxygen-containing gasifier feed 5 or the syngas product 40 (as a component thereof) can be varied depending on several operational parameters. These parameters include the H:CO molar ratio of the regeneration effluent 22 and / or the CO concentration of the regeneration effluent 22. In the case of the H:CO molar ratio, the amount of this effluent can be varied depending on whether this ratio is suitable or favorable in the reactions described above downstream, with a relatively greater amount being diverted to the syngas product 40 when the H:CO molar ratio reaches a target value. In the case of the CO concentration, the amount can be varied to maintain CO in the process, with a relatively greater amount being diverted to the oxygen-containing gasifier feed 5 when the CO concentration is above a target value. Thus, according to an exemplary embodiment, the process may include increasing the proportion of this effluent provided as a component of the syngas product and / or decreasing the proportion of this effluent provided as a component of the oxygen-containing gasifier feed in response to a measured H:CO molar ratio of the regeneration effluent reaching a target H:CO molar ratio (e.g., any target value in the range of 0.5 to 2.5, e.g., any target value in the range of 1 to 2, e.g., a target value of 1). A measured H:CO molar ratio "reaching" a target ratio may be indicated as described above for the management of stream (a). Alternatively, or in combination, the process may include increasing the proportion of this effluent provided as a component of the oxygen-containing gasifier feed and / or decreasing the proportion of this effluent provided as a component of the syngas product in response to a measured CO concentration of the regeneration effluent exceeding a target CO concentration (e.g., any target value in the range of 2 mol% to 30 mol%, e.g., any target value in the range of 5 mol% to 25 mol%, e.g., a target value of 10 mol%).

[0079] In summary, in the case of managing stream (a), this may be governed by the composition of the gasifier effluent, while in the case of managing streams (c) and / or (d), this may be governed by the composition of the effluent from vessels 200, 300. More specifically, these streams may be governed according to the extent to which the process desires to retain such compositions as constituents of the oxygen-containing gasifier feed or otherwise include such compositions in the syngas product. In the case of managing stream (b), this may be governed by the composition of the fresh gasifier feed, and more specifically, these streams may be governed according to the need to maintain a suitable rate of combustion of the carbonaceous feed and effective regeneration of spent sorbent or spent catalyst. According to other embodiments, management of streams (a), (b), (c), and / or (d) may be managed to (i) increase or maximize the yield of the syngas product, or (ii) increase or maximize the extent to which carbon is retained in the process, for example, by reducing or minimizing the extent to which carbon is removed as CO with the syngas product 40.

[0080] In summary, aspects of the present invention relate to improved control and management of gasifier effluent tar, which provides the potential for process integration and other advantages described herein. Those skilled in the art will recognize that various modifications can be made to these processes to obtain these and other advantages without departing from the scope of the present disclosure. As such, it should be understood that features of the present disclosure are susceptible to modification and / or substitution, and the specific embodiments shown and described herein are illustrative only and do not limit the invention as defined by the appended claims.

Claims

1. 1. A process for gasifying a carbonaceous feed to produce a synthesis gas product, said process comprising: contacting the carbonaceous feed with an oxygen-containing gasifier feed under gasifying conditions in a gasifier to provide a gasifier effluent comprising gasifier effluent tar; contacting at least a portion of the gasifier effluent with at least a first bed of solid sorbent under tar adsorption conditions in a tar adsorber to adsorb at least a portion of the gasifier effluent and provide a tar adsorber effluent having a reduced amount of tar; recovering said synthesis gas product from said tar adsorber effluent.

2. 10. The process of claim 1, wherein the solid adsorbent comprises a tar adsorbing material selected from the group consisting of zeolites, non-zeolitic molecular sieves (zeotypes), metal oxides, and clays.

3. The process of claim 3 wherein the metal oxide is modified with iron sulfide.

4. The solid sorbent is ammonia temperature programmed desorption (NH ３ 4. The process of claim 1, further comprising a tar-adsorbing material having at least about 15 mmol / gram of acid sites as measured by HPLC-TPD.

5. The solid adsorbent has a thickness of at least about 10 m ２ 5. The process of claim 1, comprising a tar adsorbing material having a surface area of ​​1 / g.

6. 6. The process of any one of claims 1 to 5, wherein the solid sorbent comprises one or more metals active for catalytic conversion of the gasifier effluent tar in an amount, or total amount, less than about 0.1 wt % under the tar adsorption conditions.

7. The tar adsorber effluent is a mixture of CO, CO obtained from the conversion of the gasifier effluent tar. ２ , or H ２ The process of any one of claims 1 to 6, wherein the process is substantially free of

8. The process of any one of claims 1 to 7, wherein the gasifier effluent is obtained after one or more steps of removing solids upstream of the tar adsorber.

9. 9. The process of claim 8, wherein the one or more steps of removing solids include centrifugation and filtration.

10. 10. The process of claim 9, wherein the centrifugation and filtration steps are performed upstream and downstream, respectively, of the gasifier effluent cooling step.

11. 11. The process of any one of claims 1 to 10, wherein the gasifier effluent in the tar adsorber and from the gasifier to the tar adsorber is maintained at a temperature above condensation temperature.

12. 12. The process of any one of claims 1 to 11, wherein the tar adsorption conditions comprise a temperature of from about 400°C (752°F) to about 600°C (1112°F).

13. 13. The process of any one of claims 1 to 12, further comprising replacing at least a portion of said first bed of said solid adsorbent based on an indication of sufficient utilization.

14. 14. The process of claim 13, wherein the indicator of sufficient utilization is selected from the group consisting of: (i) optionally in terms of one or more process parameters, operating time; (ii) pressure drop across the tar adsorber; (iii) tar breakthrough; or a combination thereof.

15. 15. The process of claim 13 or 14, wherein after regeneration of the second bed of solid adsorbent, the at least a portion of the first bed of solid adsorbent is replaced with at least a portion of the second bed of solid adsorbent.

16. The regeneration comprises contacting a first portion of fresh gasifier feed with the second bed of the solid sorbent under regeneration conditions to remove CO, CO resulting from oxidation, pyrolysis, and / or reformation of sorbed tar. ２ , H ２ O and / or H ２ 16. The process of claim 15, comprising providing a regenerated effluent comprising:

17. 17. The process of claim 16, wherein the oxygen-containing gasifier feed comprises a second portion of the fresh gasifier feed.

18. 18. The process of claim 16 or 17, wherein the oxygen-containing gasifier feed comprises at least a portion of the regeneration effluent.

19. 19. The process of any one of claims 1 to 18, wherein the synthesis gas product is recovered from the tar adsorber effluent after a cooling and / or washing step.

20. 1. An integrated process for carbonaceous feed gasification, tar adsorption, and solid sorbent regeneration, said process comprising: contacting the carbonaceous feed with an oxygen-containing gasifier feed under gasifying conditions in a gasifier to provide a gasifier effluent comprising gasifier effluent tar; a first bed and a second bed of solid adsorbent; (i) tar adsorption by contacting said gasifier effluent under tar adsorption conditions to adsorb at least a portion of said gasifier effluent and provide a tar adsorber effluent having a reduced amount of tar; (ii) contacting a first portion of the fresh gasifier feed under regeneration conditions to convert at least a portion of the adsorbed tar into CO, CO ２ , and / or H ２ and regeneration by oxidizing, pyrolyzing, and / or reforming the oxidized wastewater and providing a regenerated wastewater; recovering a synthesis gas product from said tar adsorber effluent.

21. 21. The process of claim 20, wherein (i) the oxygen-containing gasifier feed comprises a second portion of the fresh gasifier feed, and / or (ii) the oxygen-containing gasifier feed comprises at least a portion of the regeneration effluent.

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