Generation and utilization of ammonia water in gasification

Abstract

A gasification process utilizing carbonaceous feed and, preferably, biomass is disclosed, and the gasification process can implement one or more strategies for generating an aqueous ammonia product having a purity suitable for use in a number of applications, including applications within the overall process, in addition to alkalinity. An exemplary application involves neutralization of a sump and interfaced slag water system. Recovery of this aqueous ammonia product by condensation from the overhead vapor product of the first scrubbing device contact step can be carried out in combination with a scrubbing operation utilizing this scrubbing device contact step, and optionally, a scrubbing device container housing one, two or more additional scrubbing device contact steps, vertically separated by individual aqueous scrubbing device feeds introduced at varying axial heights.

Description

Technical Field

[0001] Cross - reference to related applications This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 461,951, filed on April 26, 2023, the content of which is hereby incorporated by reference in its entirety.

[0002] Aspects of the present invention relate to gasification processes, and more particularly, to the recovery of ammoniated water products in such processes from washing operations used, for example, to remove water - soluble contaminants from gasification plant waste liquids.

Background Art

[0003] In the production of synthesis gas (syngas) that can be further processed into transportation fuels and other value - added end products, the gasification of coal has been carried out industrially for over a hundred years. More recent efforts to develop energy independence with reduced greenhouse gas emissions have led to a strong interest in using biomass as a gasification feed, thereby providing an alternative potential source of synthesis gas and its downstream conversion products. Generally, the gasification of biomass 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 temperature and high pressure, optionally in the presence of a catalyst material, produces a waste liquid containing hydrogen and carbon oxides (CO, CO2), and hydrocarbons such as methane. This waste liquid is often referred to as synthesis gas in terms of its H2 and CO content, is significantly cooled, and must be treated to remove many undesirable components including particulates, alkali metals, halides, and sulfur compounds, in addition to by - products of gasification generally referred to as tar and oil. Further, the downstream conversion of synthesis gas to value - added products often requires an increase in the hydrogen content compared to what can be obtained from gasification alone.

[0004] Unwanted tar components in gasification wastewater, which may include condensed ring molecules such as naphthalene and pyrene, pose a significant challenge due to the tendency of such high-boiling-point molecules to condense from the vapor phase onto low-temperature surfaces encountered downstream of the gasifier. It is known that the physical accumulation of tar and oil can cause fouling / clogging of processing lines, valves, reactors, and other equipment. For these reasons, thermal decomposition of tar is commonly performed, however, this requires temperatures of approximately 1300°C, which is well above the gasifier temperature and sufficient to cause melting and / or slag formation of ash present in tar-heavy synthesis gas streams or gasifier wastewater. This molten material or slag itself can cause potential fouling and clogging due to accumulation at lower downstream temperatures, such as those encountered in equipment for upgrading synthesis gas to the final product. To mitigate these problems, the use of a sufficiently large radiant synthesis gas cooler (RSC) is considered one possible means of separating the slag via a quenching chamber at the bottom of the unit.

[0005] In order to use synthesis gas in many subsequent reactions, it is necessary to increase the molar ratio of H2:CO, as is the case with exothermic water-gas shift (WGS) reaction gases:

number

[0006] Aspects of the present invention relate to the discovery of gasification processes utilizing carbonaceous feed, preferably biomass, which can implement one or more strategies for recovering ammoniacal products, and in particular, such products having desirable properties in terms of reduced levels of contaminants (e.g., chlorides, solid particles) for use within the process. The ammoniacal products can be condensed from the synthesis gas produced by the gasification of the carbonaceous feed, following at least a single washing step (e.g., following contact with the first-stage aqueous washing feed in a first-stage washing apparatus). For example, the product can be condensed at the saturation temperature or below the saturation temperature of the synthesis gas, as in a cooled, second-stage washing apparatus. In some embodiments, this single washing step, i.e., the first washing apparatus contact step, or the first-stage washing apparatus, may be used to remove chlorides present in the washing apparatus feed. The ammoniacal products may contain ammonia derived from nitrogen present in the carbonaceous feed (e.g., biomass such as wood). Advantageously, such aqueous ammonia products (e.g., aqueous ammonia or ammonium hydroxide solutions having a pH of at least about 7.5) can provide a source of basic solutions that can meet process requirements related to neutralization and / or handling of solids, particularly in applications where chloride contamination may be a concern. Such applications include condenser sumps and slag water systems.

[0007] Embodiments of the present invention relate to gasification processes and associated configurations that enable the recycling of process condensates containing relatively "clean" (i.e., relatively low levels of other contaminants) ammonia to upstream operations where the condensate is generated, thereby offsetting makeup water requirements (e.g., those outside the process). Thus, the ammonia-contaminated and recycled aqueous products can reduce the high-cost, high-quality makeup water requirements for these upstream operations, such as radiant synthesis gas coolers (RSCs) or convection synthesis gas coolers (CSCs), more specifically, associated sumps and / or slag water systems. The ammonia present in these recycled aqueous products can facilitate pH control of these systems by neutralizing / reducing acidic chlorides (e.g., HCl) and / or other acidic species that may similarly concentrate in such systems. In this regard, slag water systems or other process water systems used in gasification processes can operate at elevated chloride levels due to the fact that chloride (in addition to nitrogen, which is the source of the ammonia ultimately recovered) is originally present in the carbonaceous feed, forms HCl under gasification / tar removal conditions, and tends to accumulate in the process lines and equipment of these systems.

[0008] Therefore, certain aspects of the present invention relate to overcoming the requirements for metallic materials (i.e., the use of upgraded metallic compositions) that have conventionally been required to achieve high levels of corrosion resistance in these systems. For example, slag water systems or other process water systems operating at high chloride (e.g., HCl) levels often require duplex stainless steel or other stainless steel to avoid corrosion / equipment failure and / or the need to inject expensive corrosion inhibitors. Other particular aspects relate to reducing or eliminating the need for expensive, high-quality (e.g., oxygen-free) makeup water for use in process sumps and so-called "dirty" water systems, including slag water systems and RSC sumps. A typical source of such makeup water is boiler feed water, which becomes contaminated when added to the process through the operation of a makeup valve. After contamination, this previously high-quality water is eventually discarded through wastewater, thereby incurring significant costs over the extended period of continuous operation of the process. The demand for high-quality makeup water to maintain such processes can become extremely costly year by year.

[0009] In view of these considerations, the processes described herein allow for the advantageous utilization of available products that have the potential to reduce both capital and operating costs, through the integration of process flow and system. One such product is aquaammonia products that can be recovered from a washing operation, typically used to remove water-soluble contaminants from gasifier wastewater. More specifically, these products may be produced by subjecting the gasifier wastewater to at least a first washing contact stage, for example, to remove all or substantially all chlorides present in the flow, and optionally together with other water-soluble contaminants that are more readily removed than ammonia, under the conditions of this first washing contact stage. The aquaammonia products may be condensed from the “clean” synthesis gas obtained after the first washing contact stage in a second washing contact stage or a higher washing contact stage (e.g., in the same vessel used to carry out the first washing contact stage), or in a condenser outside the first washing contact stage or a higher washing contact stage. In any embodiment, there is an option to return a portion of the ammonia water to the first cleaning contact stage, or to a container that performs both the first cleaning contact stage and the second or higher cleaning contact stage (for example, by adding it to the first stage aqueous cleaning feed or the recycling loop containing this feed). Importantly, the option in any embodiment is also present to add at least a portion of the ammonia water to process flows and / or associated equipment that otherwise involve acidic conditions (for example, resulting from significant levels of acidic chlorides), such as exposure of RSC to a sump or slag water system. With respect to the first cleaning contact stage, the second or higher cleaning contact stage may be considered a “cooled” contact stage, in which the contact is performed at a lower temperature.

[0010] The advantage of the processes described herein lies in the ability to effectively utilize ammonia water as an alternative to discharge into wastewater systems. This utilization may involve chloride / HCl neutralization and / or pH control, which may benefit various systems, such as preventing or minimizing costly metal material upgrades. Recycling of ammonia water products can offset or reduce the amount of clean makeup water (e.g., from an external source) required in sump and slag water systems (e.g., RSC or other synthesis gas coolers). The product also functions favorably as a coolant and can help maintain these systems below a given threshold temperature, such as the flash point when the pressure is reduced to atmospheric pressure.

[0011] Specific embodiments of the present invention relate to a process for gasifying a carbonaceous feed. The process involves contacting the carbonaceous feed with an oxygen-containing gasifier feed within a gasifier under gasification conditions to provide an unwashed gasifier wastewater containing H2, CO, and water-soluble contaminants. Some specific embodiments may further include feeding at least a portion of the unwashed gasifier wastewater as a washing feed to a washing operation to remove at least a portion of the water-soluble contaminants and provide a washed gasifier wastewater. These specific embodiments may also include recovering ammonia-derived aqueous products from the washing operation after at least a first washing contact step. Other specific embodiments may further optionally include feeding at least a portion of the unwashed gasifier wastewater as a washing feed to a washing operation following an operation between one or more downstream of the gasifier to remove at least a portion of the water-soluble contaminants and provide a washed gasifier wastewater. These other specific embodiments may also include recovering ammonia-derived aqueous products and chloride-enriched aqueous products (e.g., a chloride-enriched first-stage purge against the washing device feed) from the washing operation (e.g., following at least a first washing device contact step).

[0012] These and other embodiments, aspects, and advantages relating to the present invention will become apparent from the following embodiments for carrying out the invention. [Brief explanation of the drawing]

[0013] Exemplary embodiments of the present invention and their advantages can be better understood by referring to the following description in conjunction with the accompanying drawings, where the same reference numerals are used to identify the same features.

[0014] [Figure 1] A flow chart illustrating one embodiment of a process for the gasification of carbonaceous feed is depicted, which employs a number of possible features as described herein, including a washing operation in which the ammonia aqueous product is recovered. [Figure 2] A flow diagram is provided to illustrate in more detail the aqueous and gaseous flows around the first stage cleaning apparatus and the second stage cleaning apparatus of this operation, which represent a specific aspect of the cleaning operation. [Figure 3] A flow diagram is drawn to illustrate in more detail the aqueous and gaseous flow around a combination of a first-stage cleaning device and an overhead condenser in the first stage of this operation, which represents a specific aspect of the cleaning operation.

[0015] For the sake of simplification, multiple features are illustrated and explained in each of the diagrams, but please understand that not all features (e.g., all individual actions, as well as their associated process flows and equipment) are required, and various specific features can be implemented independently of others.

[0016] For the sake of explanation and understanding, Figures 1 to 3 provide an overview of these and other features for an implementation in the gasification process. Some related equipment, such as specific vessels, heat exchangers, valves, instrumentation, and utilities, are not shown because their specific description is not essential to the implementation or understanding of various aspects of the present invention. Such equipment will be readily apparent to those skilled in the art who are familiar with the present disclosure. Other processes having configurations and partially determined components for producing conversion products such as synthesis gas and / or renewable liquids, and for specific processing purposes, according to other embodiments within the scope of the present invention, will also be readily apparent. [Modes for carrying out the invention]

[0017] In this specification, the expressions “weight%” and “mol%” are used to represent weight percentage and mole percentage, respectively. The expressions “wt-ppm” and “mol ppm” represent weight and mole fraction, respectively. For ideal gases, “mol%” and “mol ppm” correspond to volume percentage and volume parts per million, respectively. The terms “barg” and “psig,” when used herein, specify gauge pressure (i.e., pressure above atmospheric pressure) in units of bars and pounds per square inch, respectively, while the terms “bar” and “psi,” as used herein, specify absolute pressure. For example, gauge pressures of 0 barg and 0 psig correspond to absolute pressures of approximately 1 bar and 14.5 psi, respectively.

[0018] As used herein, the term “substantially” refers to at least 95%. For example, the phrase “substantially all” may be replaced with “at least 95%.” The phrases “all or part” or “at least part” mean, in certain embodiments, to include “at least 50% of,” “at least 75% of,” “at least 90% of,” and, in preferred embodiments, “all.” Similarly, designated parts such as “first part” or “second part” may represent these percentages of the whole (but not all) and, in particular, these percentages of the entire process flow they refer to (but not all).

[0019] In the case of a continuous process, any reference to any starting material, intermediate product, or final product, preferably all of which are process flow, should be understood to mean “all or part” of such starting material, intermediate product, or final product, given that some parts may not be used due to sampling, purging, diversion for other purposes, mechanical losses, etc. Thus, for example, the phrase “feed the washing operation with ... as a washing device feed” should be understood to mean supplying all or part of the washing device feed to the washing operation. As with when “all or part” is understood to mean “all or part,” the phrase should further be understood to encompass the specific and preferred embodiments described above.

[0020] A typical process for the gasification of carbonaceous feed described herein may include a number of unit operations, one of which is performed or executed “before,” “prior to,” or “upstream of” another of which operations, or one of which is performed or executed “after,” “following,” or “downstream of” another of which operations. These parenthetical phrases, referring to the order in which one operation is performed or executed relative to another, refer to the entire process flow, as will be understood by those skilled in the art who are familiar with this disclosure. More specifically, the overall process flow may be defined by bulk gasifier wastewater flows, including bulk flows of both unwashed and washed gasifier wastewater, as well as bulk WGS product flows, which are subjected to the operations as defined herein. To the extent that the parenthetical phrases are used to indicate order, in specific embodiments, these phrases mean that one operation is immediately preceding or immediately following another; however, more generally, these phrases do not preclude the possibility of intervening operations. Thus, for example, one or more “downstream operations of the gasifier” may, in a particular embodiment, refer to operations immediately following the gasifier, such as the tar removal operation in the embodiment illustrated in Figure 1. However, more generally, and preferably, in the embodiment illustrated in Figure 1, this phrase refers to any or any combination of operations following the gasifier, whether or not intervening operations are present, such as one or more quenching operations, radiant synthesis gas cooler (RSC) or convection synthesis gas cooler (CSC), and / or filtration operations following the tar removal operation as an intervening operation. Therefore, to the extent that a typical process described herein is defined as including a particular unit operation, such a process does not preclude the use of other operations, whether or not they are specifically described herein, except in particular statements or designations (e.g., the use of the phrase “consisting of”).

[0021] The specific processes described herein are defined by a gasifier, a cleaning operation downstream of the gasifier (e.g., a wet cleaning unit), and a WGS operation downstream of the cleaning operation. The gasifier provides “gasifier wastewater,” and the WGS operation provides “WGS products.” The term “gasifier wastewater” is a general term referring to the wastewater of the gasifier, regardless of whether it has been subjected to one or more operations downstream of the gasifier and upstream of the WGS operation. More specifically, “gasifier wastewater” may be specified as “uncleaned gasifier wastewater” or “cleaned gasifier wastewater,” which are also general terms but add more specificity in that they indicate the characteristics of the gasifier wastewater depending on whether it has been subjected to a cleaning operation.

[0022] The terms "gasification plant waste liquid" and "unwashed gasification plant waste liquid" include (i) waste liquid directly provided by a gasification plant, i.e., "as-is gasification plant waste liquid", (ii) as-is gasification plant waste liquid having a lower concentration of tar and oil with respect to the as-is gasification plant waste liquid, i.e., waste liquid of the as-is gasification plant that has been subjected to at least a tar removal operation, i.e., "tar-depleted gasification plant waste liquid", (iii) as-is gasification plant waste liquid having a lower temperature and a higher moisture (H2O) concentration with respect to the as-is gasification plant waste liquid resulting from direct quenching with water (e.g., partial quenching), i.e., waste liquid of the as-is gasification plant that has been subjected to at least a dry quenching operation, i.e., "quenched gasification plant waste liquid", (iv) as-is gasification plant waste liquid having a lower temperature with respect to the as-is gasification plant waste liquid resulting from heat transfer for external steam generation, i.e., waste liquid of the as-is gasification plant that has been subjected to at least a radiant syngas cooler (RSC) or a convective syngas cooler (CSC), i.e., "cooled gasification plant waste liquid", (v) as-is gasification plant waste liquid having a low solid particle content, which may provide all or part of "heated scrubber feed" or, alternatively, all or part of "scrubber feed" in another manner, i.e., waste liquid of the as-is gasification plant that has been subjected to at least a filtration operation, i.e., "filtered gasification plant waste liquid", (vi) as-is gasification plant waste liquid having a lower temperature with respect to the as-is gasification plant waste liquid that has been subjected to at least heat removal (e.g., for generating steam), i.e., waste liquid of the as-is gasification plant that may provide all or part of "scrubber feed", and (vii) may include more specific terms that designate as-is gasification plant waste liquid subjected to any other operation upstream of the washing operation, whether or not specifically described herein.

[0023] Similarly, the terms "gasifier waste liquid" and "washed gasifier waste liquid" include (viii) the as-received or unwashed gasifier waste liquid that is subjected to a washing operation to reduce the content of water-soluble contaminants (e.g., chlorides), and (ix) whether or not specifically described herein, the as-received or washed gasifier waste liquid that is subjected to other operations downstream of the washing operation. The terms "gasifier waste liquid", "unwashed gasifier waste liquid", and "washed gasifier waste liquid", and any one of the more specific examples (i)-(ix) of these terms, include products (e.g., flow streams) upstream of the WGS operation and, optionally, can be supplied to the WGS operation.

[0024] The term "WGS product" is a general term that refers to the product of the WGS operation, all or a portion of which, in accordance with a particular embodiment, can be provided to a syngas conversion operation or a syngas separation operation to provide a value-added product, a renewable syngas conversion product or a renewable syngas separation product. The term "WGS product" includes all or a portion of the products directly provided from the WGS operation, or such products after being subjected to purification such as heating, cooling, pressurization, depressurization, and / or acid gas removal. The term "syngas" or alternatively "syngas product" is generally used herein to refer to the gasifier waste liquid, i.e., the unwashed or washed gasifier waste liquid as defined above, or the WGS product, insofar as it relates to a stream containing H2 and CO.

[0025] Specific examples of renewable synthesis gas conversion products and renewable synthesis gas separation products include both renewable liquid products (e.g., liquid hydrocarbons or methanol) and renewable gaseous products (e.g., renewable natural gas (RNG) or renewable hydrogen). The modifiers “synthesis gas conversion” and “synthesis gas separation,” as well as the modifiers “conversion” and “separation,” as used in the terms “renewable synthesis gas conversion products,” “renewable synthesis gas separation products,” “gaseous conversion by-products,” “liquid conversion by-products,” and “gaseous separation by-products,” are intended to more specifically specify that these products and by-products are obtained from synthesis gas conversion operations (e.g., including the Fischer-Tropsch reaction step, the methanol synthesis reaction step, or the methane reaction step) or synthesis gas separation operations (e.g., including a hydrogen purification step, such as synthesis gas separation by pressure fluctuation adsorption (PSA) and / or the use of membranes). Any such synthesis gas conversion or separation operation is preferably performed on a WGS product in which the molar ratio of H2:CO can be increased to a more favorable value, from the viewpoint of efficiently carrying out the desired conversion or separation. The use of the modifiers “separation” and “conversion” in the terms used above to modify products and by-products does not preclude these products and by-products from being obtained from a combination of separation and conversion.

[0026] The typical gasification processes described herein are defined by various possible operations performed downstream of the gasifier, which may include tar removal operations; cooling operations such as quenching, RSC and / or CSC; filtration operations; scrubbing operations such as by using a boiler; scrubbing operations; WGS operations; and synthesis gas conversion operations. Specific possible features of the gasifier, as well as these downstream operations, and the associated process flows and conditions, are provided in the following description by preferred embodiments, any other embodiments defined in the claims, and embodiments illustrated in Figures 1 to 3.

[0027] Gasification device A typical process involves bringing a carbonaceous feed into contact with an oxygen-containing gasifier feed under gasification conditions within a gasifier, and supplying gasifier wastewater containing synthesis gas (for example, unprocessed gasifier wastewater).

[0028] This carbonaceous feed may include coal (e.g., high-quality anthracite or bituminous coal, or less high-quality subbituminous, lignite, or peat), petroleum coke, asphaltenes, and / or liquid petroleum residues, or other petroleum-derived materials. In preferred embodiments, the carbonaceous feed may include biomass. The term "biomass" refers to renewable (non-petroleum-derived) material derived from living organisms inhabiting the Earth's surface or the Earth's oceans, rivers, and / or lakes. Typical biomass may include any plant material, or mixtures of plant materials, such as hardwoods (e.g., whitewood), conifers, hardwood or conifer bark, lignin, algae, and / or remna (seaweed). Energy crops, or otherwise, other agricultural residues (e.g., logging residues), or other types of plant waste or plant-derived waste may also be used as plant material. Specific exemplary plant materials include maize fiber, maize stalks and leaves, and sugarcane bagasse, in addition to “target” energy crops such as switchgrass, Japanese pampas grass, and algae. Short-cycle forest products, such as energy crops, include alder, ash, beech, birch, eucalyptus, poplar, willow, paper mulberry, Australian blackwood, plane tree, and various types of cypress. 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. Thus, a typical carbonaceous feed includes or comprises any of these types of biomass. Specific carbonaceous feeds containing biomass include municipal solid waste (MSW) or MSW-derived products, such as reduced-grade fuel (RDF). Carbonaceous feeds may include combinations of petroleum-derived materials and renewable materials, including those described above. A preferred carbonaceous feed is wood (for example, in the form of wood chips).

[0029] In the gasifier (or, more specifically, the gasification reactor of the gasifier), the carbonaceous feed is subjected to partial oxidation in the presence of an oxygen-containing gasifier feed and is added in generally limited amounts to supply only 20-70% of the oxygen necessary for complete combustion. The oxygen-containing gasifier feed generally contains other oxygenated gaseous components, including H2O and / or CO2, which can play a similar role to the oxidizer of the carbonaceous feed. The oxygen-containing gasifier feed may refer to all gases supplied to or added to the gasifier, or, if not, to gases separate from other gases supplied to or added, whether upstream of the gasifier or later combined within the gasifier. For example, the oxygen-containing gasifier feed may be introduced into the gasifier along with steam or a portion of steam generated elsewhere in the process (e.g., steam generated in the RCS or steam generated in the CSC) and used as a separate feed. By bringing a carbonaceous feed into contact with an oxygen-containing gasifier feed within the gasifier, gasifier wastewater, and more specifically, as-is gasifier wastewater as a direct product from the gasifier, is provided. One or more reactors in the gasifier (e.g., in series or parallel) may operate under the gasification conditions present within such reactors, which generally include temperatures of about 500°C (932°F) to about 1000°C (1832°F), typically about 816°C (1500°F) to about 1038°C (1900°F). Other gasification conditions may include atmospheric pressure or high pressure, such as absolute pressures of about 0.1 megapascals (MPa) (14.5 psi) to about 10 MPa (1450 psi), typically about 1 MPa (145 psi) to about 3 MPa (435 psi), or about 0.5 MPa (72 psi) to about 2 MPa (290 psi).

[0030] Gasification reactor configurations include counter-flow fixed beds ("updraft"), parallel-flow fixed beds ("downdraft"), and jet plasma. Various solid catalysts having different activities for one or more desired functions during gasification, such as tar reduction, improved H2 yield, and / or reduced CO2 yield, may be used. Limestone may be added to the gasification reactor, for example, to promote tar reduction by decomposition. Various catalytic materials, including solid particles of dolomite, supported nickel, alkali metals, and alkali metal compounds such as alkali metal carbonates, bicarbonates, and hydroxides, may be used in the gasification reactor. Often, the gasification apparatus operates in a gasification reactor having a fluidized bed of carbonaceous feed particles (and, optionally, solid catalyst particles), with an oxygen-containing gasification feed, and optionally a separate fluidized H2O and / or CO2-containing feed, supplied upward through the particle bed. Exemplary types of fluidized beds include bubbling fluidized beds and jet fluidized beds.

[0031] In addition to the tar in the gasifier wastewater, the as-is gasifier wastewater contains, as described below, carbon present in the carbonaceous feed, as well as CO, CO2, and methane (CH4) generally derived from both H2 and / or H2O, along with other components in trace concentrations. According to the embodiment illustrated in Figure 1, the as-is gasifier wastewater 16 can be obtained directly from the gasifier 50 before further operations described herein.

[0032] The gasifier wastewater as is, or any gasifier wastewater subjected to one or more operations as described herein, may contain synthesis gas, i.e., both H2 and CO, and these components may be present in varying amounts (concentrations) and preferably in a total amount of more than about 25 mol% (e.g., about 25 mol% to about 95 mol%), more than about 50 mol% (e.g., about 50 mol% to about 90 mol%), or more than about 65 mol% (e.g., about 65 mol% to about 85 mol%). With respect to such total amounts (concentrations), the H2:CO molar ratio of gasifier wastewater may be suitable for use in downstream synthesis gas conversion operations (reactions or separations), such as (i) conversion to renewable synthesis gas conversion products containing high molecular weight hydrocarbons and / or alcohols with different numbers of carbon atoms via the Fischer-Tropsch transform, or (ii) conversion to renewable synthesis gas conversion products containing methanol via a catalytic methanol synthesis reaction, or (iii) conversion to renewable synthesis gas conversion products containing renewable natural gas (RNG) via catalytic methanation, which increases the methane content in the resulting RNG stream, or (iv) separation of renewable synthesis gas separation products containing purified hydrogen. However, more typically, WGS operation is required to achieve a preferred H2:CO molar ratio and / or preferred H2 concentration with respect to these or other downstream synthesis gas conversion and separation operations. For example, if the WGS operation obtains purified hydrogen as a regenerative synthesis gas separation product (e.g., by utilizing one or more PSA and / or membrane separation steps), then parameters (e.g., reactor temperature and / or catalyst type) for obtaining the maximum yield / concentration of hydrogen through the consumption of CO present in the synthesis gas upstream of this operation may be included.

[0033] Independent of, or in combination with, the typical amounts (concentrations) of H2 and CO described above, the gasification wastewater may contain CO2 in amounts of, for example, at least about 2 mol% (e.g., about 2 mol% to about 30 mol%), at least about 5 mol% (e.g., about 5 mol% to about 25 mol%), or at least about 10 mol% (e.g., about 10 mol% to about 20 mol%). Independent of, or in combination with, the typical amounts (concentrations) of H2, CO, and CO2 described above, the gasification wastewater may contain CH4 in amounts of, for example, at least about 0.5 mol% (e.g., about 0.5 mol% to about 15 mol%), at least about 1 mol% (e.g., about 1 mol% to about 10 mol%), or at least about 2 mol% (e.g., about 2 mol% to about 8 mol%). Together with any water vapor (H2O), these non-condensing gases H2, CO, CO2, and CH4 may constitute substantially the entire composition of the gasification wastewater. In other words, these non-condensing gases, and any water, may be present in the gasification wastewater in a total amount of at least about 90 mol%, at least about 95 mol%, or even more, at least about 99 mol%.

[0034] Tar removal operation The raw gasification wastewater obtained directly from a gasifier generally contains gasification wastewater tar, which typically necessitates a tar removal operation for further treatment. This gasification wastewater tar may contain compounds referred to in the art as "tar" and "oil," more specifically hydrocarbons and oxygenated hydrocarbons having molecular weights exceeding that of methane, which may be present in the gasification wastewater at concentrations ranging from several weight ppm to several weight percent. Certain types of these compounds with relatively high molecular weights are further characterized by their tendency to condense at low temperatures and coat the internal surfaces of downstream processing equipment, causing undesirable fouling, corrosion, and / or clogging. These compounds can also interfere with subsequent processing steps or synthesis gas conversion operations to upgrade the synthesis gas into higher-value products, which are best carried out by using a high-purity feed gas (for example, from a stability standpoint).

[0035] For these reasons, certain undesirable compounds include hydrocarbons and oxygenated hydrocarbons (C6) having six or more carbon atoms. + These include hydrocarbons and oxygenated hydrocarbons, with benzene, toluene, xylene, naphthalene, pyrene, phenol, and cresol being specific examples. These compounds are usually added directly to the gasification wastewater at a rate of 1-100 g / Nm³. 3 These compounds are present in total quantities. Therefore, removing these organic compounds (e.g., by conversion) is generally necessary to avoid serious problems caused by the accumulation of organic compounds over time. Other types of tar and oil, such as ethane, ethylene, and acetylene, do not condense from gasification wastewater, but nevertheless "bond" hydrogen and carbon by reducing the overall yield of H2 and CO as desired components of synthesis gas.

[0036] Depending on the specific tar removal operation, the tar and oil in the as-is gasifier wastewater can be converted by oxidation, decomposition, and / or reforming, either catalytically or non-catalytically, to provide additional H2 and CO to the tar-depleted gasifier wastewater. The tar conversion reaction can utilize available O2 or oxygen sources (e.g., H2O and / or CO2) present in and / or added to the synthesis gas. From the perspective of gasifier wastewater tar, converting these compounds together with methane, which contains most of the energy in the as-is gasifier wastewater, can substantially increase the overall synthesis gas yield. Thus, according to certain embodiments, a tar removal operation, which may more specifically be a tar conversion operation, can effectively reduce the concentration of compounds that are generated in the gasifier and present as tar in the as-is gasifier wastewater. In general, tar removal, and more specifically, tar conversion reactions, can be carried out at higher temperatures than those used in the gasifier, so that the tar-depleted gasifier waste liquid obtained directly from the tar removal operation can have temperatures exceeding approximately 1000°C (e.g., approximately 1000°C (1832°F) to approximately 1500°C (2732°F) such as approximately 1204°C (2200°F) to approximately 1427°C (2600°F)).

[0037] According to one embodiment, the tar removal operation may be used for the conversion (e.g., reforming) of tar and methane through non-catalytic partial oxidation (Pox) within the reactor used for this operation. The efficiency of this specific operation can be enhanced using high-temperature oxygen burner (HOB) technology, in which excess oxygen is mixed with a small amount of fuel (e.g., natural gas, propane, or recycled synthesis gas). Combustion of this fuel within the reactor can result in a temperature increase above 1100°C (2012°F), accelerating the combustion products and excess oxygen to the speed of sound through the nozzle, thereby forming a turbulent jet that improves the mixing between the tar / methane-containing synthesis gas and the reactive high-temperature oxygen stream. HOB-based systems can effectively improve the synthesis gas yield.

[0038] In tar removal operations utilizing catalytic conversion of tar and methane, the operation may include a reactor containing a bed of catalysts, for example, in the form of a secondary fluidized bed downstream of the gasifier, containing solid or supported Ni, solid or supported Fe, and / or dolomite. Other catalysts for tar conversion include olivine, limestone, zeolite, and further metal-containing charcoal produced from gasification. Catalytic tar conversion, as in the case of non-catalytic processes that may be carried out in tar removal operations, may also include introducing additional oxygen and / or vapor reactants into the reactor used in this operation.

[0039] According to other specific embodiments, the tar removal operation may selectively adsorb tar and oil from the as-is gasification wastewater using a suitable liquid or solid adsorbent. For example, the tar removal operation may be carried out in conjunction with an oil absorption system, thereby passing (contacting) the as-is gasification wastewater through a liquid medium such as a bio-oil solution and extracting the tar and oil based on their selective solubility. The liquid adsorbent may be burned after consumption.

[0040] Regardless of the specific method by which the tar removal operation is performed, the as-is gasification wastewater may contain tar and oil (e.g., existing as the compounds described above) in amounts of about 0.01% to about 5% by weight, for example, about 0.1% to about 3% by weight or about 0.5% to about 2% by weight, or in total. The tar removal operation may be effective in substantially or completely removing this gasification wastewater tar. For example, the tar-depleted gasification wastewater coming out of or obtained directly from this operation may contain tar and oil in amounts of less than about 0.5% by weight, less than about 0.1% by weight or less than about 0.01% by weight, or in total. A typical level of tar and oil removal (e.g., by conversion), measured over the tar removal operation, may be at least about 90%, at least about 95%, or even more, at least about 99%, resulting in tar-depleted gasification wastewater that is substantially or completely free of tar.

[0041] Rapid cooling operation High-temperature gasification wastewater, such as tar-depleted gasification wastewater from tar removal operations, can be cooled by various techniques, including radiant and / or convective heat exchange. In typical embodiments, at least one quenching operation, and preferably a dry quenching operation, may be used, where water is directly added to the gasification wastewater to contribute to its overall water content, thereby favoring H2 production via a WGS reaction that is equilibrium-limited (i.e., to provide an increased H2:CO molar ratio and an increased H2 concentration). The dry quenching operation utilizes the sensible heat of the gasification wastewater to vaporize the injected water, which is sufficient to obtain quenched gasification wastewater at a desired cooling temperature. When dry quenching is used without further use of RSC, the quenched gasifier wastewater may have a temperature of about 400°C (752°F) to about 900°C (1652°F), and preferably about 538°C (1000°F) to about 816°C (1500°F), allowing for further processing. A typical process may include a subsequent filtration operation (passing through a filter) to remove solid particles (e.g., dust) after sufficient further cooling (e.g., using RSC or CSC). In preferred embodiments, only partial quenching, rather than complete quenching, is used in the quenching operation, so that the quenched gasifier wastewater coming out of or obtained directly from the dry quenching operation is above its dew point, i.e., not saturated. In general, dry quenching can facilitate rapid and efficient cooling through direct contact between the high-temperature gasifier wastewater and water or other aqueous quenching bodies.

[0042] Radiative synthesis gas cooler (RSC) or convection synthesis gas cooler (CSC) As described herein, according to preferred embodiments, a quenching operation characterized by direct contact between synthesis gas (e.g., tar-depleting gasifier wastewater exiting a tar removal operation) and a rapid coolant such as water, combined with RSC or CSC, can provide effective cooling for further downstream operations. Alternatively, or in combination, RSC may be used for the effective removal of ash and formed slag. For example, RSC or CSC may be used to cool the quenched gasifier wastewater exiting a quenching operation to provide cooled gasifier wastewater, which optionally has a temperature within the range described above, and / or the cooled gasifier wastewater has a temperature of about 250°C (482°F) to about 600°C (1112°F), and preferably about 275°C (527°F) to about 350°C (662°F), to allow for subsequent filtration. RSCs or CSCs can operate by indirect heat transfer, such as when they have a shell-and-tube structure, typically generating steam from a portion of the heat recovered from gasification and tar removal operations. According to a more specific embodiment, an RSC or CSC can operate as a boiler (e.g., a fire-tube boiler or a water-tube boiler) for the generation of medium-pressure and / or high-pressure steam.

[0043] Filtration operation Filtration operations using any suitable filter may be used to remove solid particles (particulate matter) from gasifier wastewater, such as cooled gasifier wastewater coming out of an RSC or CSC, as described above. In the case of biomass gasification, these solid particles may include charcoal, tar, soot, and ash, any of which may generally contain alkali metals such as sodium. Corrosive and / or harmful species, such as chloride, arsenic, and / or mercury, may also be present in such solid particles. For example, high-temperature filtration using a bundle of metal or ceramic filters may generally be sufficient to reduce the solid particle content in the gasifier wastewater, thereby providing filtered gasifier wastewater coming out of the filtration operation or obtained directly from the filtration device, with solid particles of less than 1 ppm by weight, and optionally less than 0.1 ppm by weight. In typical embodiments, the filtered gasifier wastewater may have temperatures within the range described above with respect to cooled gasifier wastewater.

[0044] In some embodiments, the filtration operation may be performed upstream (before) the tar removal operation to allow the subsequent operation to be performed more effectively. Removal of solid particles of varying average particle sizes by filtration or other techniques may be performed at any of a number of possible stages throughout the process. For example, removal of coarse solids by centrifugal separation may be performed immediately downstream of the gasifier and / or further in situ within the gasifier (e.g., using an internal cyclone to remove solid particles positioned in the space above the fluidized particle bed).

[0045] The filtration operation may be followed by, or integrated with, an additional cleaning operation, which may involve contact with a solid "abrasive" material such as a carbon bed, thereby further purifying the gasification wastewater and, for example, further reducing its tar and total hydrocarbon content. This can provide more thorough removal of benzene, naphthalene, pyrene, toluene, phenol, and other condensing chemical species that may adversely affect downstream operations, such as by depositing on the equipment.

[0046] Washing device feed cooler Prior to the cleaning operation, heat may be removed from the gasification wastewater, such as filtered gasification wastewater, which is obtained either from or directly from the filtration operation as described above. According to some embodiments, a boiler and / or an air cooler (using a fan) may be used as a cleaning feed cooler to perform indirect heat exchange. Regardless of the specific type, this cooler may more specifically perform cooling of the heated cleaning feed to provide a cleaning feed (or cooled cleaning feed) that is directly fed into the cleaning device, in which case both the heated and cooled flows may contain uncleaned gasification wastewater, such as filtered gasification wastewater. Thus, according to specific embodiments, it can be understood that “heated cleaning feed” may correspond to or include “filtered gasification wastewater.” Also, heated cleaning feed / filtered gasification wastewater and cleaning feed / cooled cleaning feed may be specific examples of “uncleaned gasification wastewater.” In some embodiments, the cleaning device feed cooler may not be present, for example, when sufficient cooling occurs upstream of the filtration operation and the filtered gasifier wastewater is used directly in the cleaning operation. In such cases, the “cleaning device feed” may correspond to or include the “filtered gasifier wastewater.”

[0047] In typical embodiments, the scrubbing feed may generally be cooled to a temperature of about 200°C (392°F) to about 450°C (842°F), and preferably about 225°C (437°F) to about 325°C (617°F), upstream and / or downstream of the filtration operation, whether or not it is cooled in a scrubbing feed cooler. Such temperatures may correspond to the scrubbing gas inlet temperature or the scrubbing operating temperature. When a scrubbing feed cooler is used downstream of the filtration operation, as illustrated in Figure 1, the heated scrubbing feed directly upstream of this cooler may have a temperature within the range given above with respect to the filtered gasifier wastewater, which may be about 250°C (482°F) to about 600°C (1112°F), and preferably about 275°C (527°F) to about 350°C (662°F).

[0048] Cleaning operation The scrubbing operation may be used to remove water and water-soluble contaminants from uncleaned gasifier wastewater, such as filtered gasifier wastewater exiting the filtration operation, and may optionally be performed following cooling of this flow by a scrubbing feed cooler. For example, filtered gasifier wastewater may serve as feed to a boiler providing cooled wastewater upstream of the scrubbing operation, following indirect heat exchange, and all or at least a portion of this wastewater may provide the scrubbing feed for the scrubbing operation. Alternatively, in the absence of a scrubbing feed cooler, the filtered gasifier wastewater at the temperature exiting the filtration operation may substantially serve as feed for the scrubbing operation. In either case, the scrubbing operation itself may provide further cooling of the scrubbing feed. For example, the cleaned gasifier wastewater exiting the scrubbing device may have a temperature of about 35°C (95°F) to about 100°C (212°F), and preferably about 43°C (110°F) to about 66°C (150°F).

[0049] Washing operations, such as wet washing, can be effective in removing water-soluble contaminants such as chlorides (e.g., in the form of HCl), ammonia, and HCN, as well as fine solid particles (e.g., char and ash). For example, when using a wet washing apparatus, unwashed gasifier wastewater, such as the washing apparatus feed obtained after cooling, can optionally be fed into a tray column to perform co-flow or backflow contact with water or an aqueous solution. Further cooling in this column to a temperature below 100°C (212°F) can be used to aid droplet condensation to improve the effectiveness of contaminant removal. The washing operation can be used to provide washed gasifier wastewater exiting or obtained directly from this operation, having a total amount of chlorides, ammonia, less than 1 ppm by weight, and optionally less than 0.1 ppm by weight of solid particles. The washing operation also generally serves to remove water, so the water content of the washed gasifier wastewater is reduced relative to the water content of the washing apparatus feed.

[0050] According to preferred embodiments as described herein, the scrubbing operation may also provide an aqueous product stream or an aqueous ammonia product in which ammonia from the gasifier wastewater (e.g., filtered gasifier wastewater) is selectively dissolved and thereby removed from this stream. The scrubbing operation may further provide an aqueous product stream or a first-stage purge in which chloride from the gasifier wastewater (e.g., filtered gasifier wastewater) is selectively dissolved and thereby removed from this stream.

[0051] WGS operation The water-gas shift (WGS) operation reacts CO present in the gasifier wastewater, for example, the cleaned gasifier wastewater immediately after a scrubbing operation, with vapor to increase the H2 concentration (and CO2 concentration). In this way, the cleaned gasifier wastewater can be characterized as a feed for the WGS operation (WGS feed). Following tar removal, filtration, and scrubbing operations, the cleaned gasifier wastewater / feed for the WGS operation may have desirable properties for use in this operation, in that it is free or substantially free of water-soluble contaminants as described above, as well as tar and particulate matter.

[0052] According to some embodiments, the cleaned gasifier waste / feed to the WGS operation may be heated and / or supplemented with moisture (steam) to further improve the properties of the WGS feed for a kinetically and / or thermodynamically favorable WGS reaction, which preferably increases the H2:CO molar ratio and / or H2 concentration of the WGS product. For example, the feed may be heated to a temperature of about 225°C (437°F) to about 475°C (887°F), preferably about 260°C (500°F) to about 399°C (750°F) before being introduced into the WGS operation. The moisture content of the feed may be increased by utilizing an auxiliary steam source, such as at least a portion of the generated steam provided from a steam generation (e.g., using a boiler) as described above. For example, at least a portion of the steam generated in a boiler (e.g., low-pressure or medium-pressure steam) may be supplied to or added to a WGS operation (e.g., one or more reactors used during this operation) to improve the overall thermal balance / thermal integration. In a WGS operation, the use of steam in amounts exceeding the stoichiometric ratio can be beneficial for many purposes, particularly in adiabatic fixed-bed reactors. These include shifting equilibrium toward hydrogen production, adding heat capacity to limit the rise in exothermic temperature, and minimizing side reactions such as methane.

[0053] The reactors used in WGS operation may contain suitable catalysts, such as those containing one or more of Co, Ni, Mo, and W on a solid support, specific examples of which are sulfur-tolerant Co / Mo and Ni / Mo catalysts. Other catalysts used in this operation (i.e., contained in one or more WGS reactors) include copper-containing catalysts such as Cu-Zn-Al and / or zinc-containing catalysts; chromium-containing catalysts; iron oxide; ferrite zinc; magnetite; chromium oxide; and any combination thereof (e.g., Fe2O3-Cr2O3 catalysts).

[0054] In a typical WGS operation, two or more reactors with interstage cooling are used, from the standpoint of the thermodynamic properties of the WGS reaction. For example, a high-temperature shift (HTS) reactor may operate at a reactor inlet temperature of about 310°C (590°F) to about 450°C (842°F), with a more favorable reaction kinetics and less favorable equilibrium transformation. The wastewater from the HTS may then be cooled to a suitable temperature for the reactor inlet of a low-temperature shift (LTS) reactor, such as about 200°C (392°F) to about 250°C (482°F), to provide a less favorable reaction kinetics and a more favorable equilibrium transformation. Thus, the combined effect of the HTS and LTS reactors results in a high conversion to H2 with a favorable residence time. In some cases, it may be desirable to use three or more reactors or catalyst beds to carry out the WGS reaction, in which case cooling between successive reactors or catalyst beds is also involved.

[0055] In this way, the WGS operation may be used to provide an immediate WGS product that exits or is directly obtained from this operation, having an increased H2:CO molar ratio and increased H2 concentration relative to the feed to the WGS operation or the synthesis gas obtained from an upstream operation (e.g., filtered gasifier wastewater or cooled gasifier wastewater). For example, the immediate WGS product may have an H2:CO molar ratio of about 0.5 to about 3.5, about 1.0 to about 3.0, or about 1.5 to about 2.5, and / or a hydrogen concentration of at least about 35 mol% (e.g., about 35 mol% to about 80 mol%), at least about 40 mol% (e.g., about 40 mol% to about 70 mol%), or at least about 45 mol% (e.g., about 45 mol% to about 65 mol%). These properties of the immediate WGS product can be controlled by bypassing the WGS operation more or less (e.g., by diverting a smaller or larger portion of the feed to this operation around the operation to provide a portion of the immediate WGS product). The WGS operation may be even more beneficial in terms of converting carbonyl sulfide (COS) to H2S, which can be recycled and more easily removed elsewhere in the process, such as in the acid gas removal operation, or, if applicable, at least to some extent, in the washing operation.

[0056] Synthesis gas conversion or separation operation In some embodiments, the processes described herein may also include synthesis gas conversion or synthesis gas separation operations to produce renewable synthesis gas conversion products or renewable synthesis gas separation products, for example, liquid hydrocarbons, methanol, or RNG as conversion products, and purified hydrogen as separation products. In the case of liquid hydrocarbon production, the synthesis gas conversion operation may include a Fischer-Tropsch (FT) reaction step. One or more reactors in this step are used to process a synthesis gas mixture of hydrogen (H2) and carbon monoxide (CO) by successive cleavage of CO bonds and formation of CC bonds with hydrogen incorporation. This mechanism produces hydrocarbons, particularly linear alkanes, whose molecular weight distribution can be controlled to some extent by changing the FT reaction conditions and catalytic properties. Such properties include pore size and other properties of the carrier material. The selection of the FT catalyst and its active metal (e.g., Fe or Ru) may also affect the yield of the FT product in other respects, such as the formation of oxygen-containing compounds.

[0057] In methanol production, the synthesis gas conversion operation may include a methanol synthesis reaction step. One or more reactors in this step are used to form methanol according to the following catalytic reaction: CO + 2H2 → CH3OH (1) Typical catalysts for methanol synthesis via this pathway are characterized as "CZA," referring to copper and zinc on alumina, or Cu / ZnO / Al2O3. Alternatively, or in combination, various other catalytic metals and their oxides may be used, including one or more of W, Zr, In, Pd, Ti, Co, Ga, Ni, Ce, Au, Mn, and combinations thereof.

[0058] In the case of methane production as a synthesis gas conversion operation to provide renewable natural gas (RNG) products, one or more methanation reactors (e.g., in series or parallel) can react CO and / or CO2 with hydrogen to provide a high-temperature methanation product with a significantly higher methane concentration than the initially present methane concentration (e.g., in the WGS product). Suitable catalysts for use in methanation reactors include ruthenium and / or other precious metals, as well as supported metals such as molybdenum and tungsten. However, supported nickel catalysts are generally the most cost-effective. In many cases, methanation reactors operate using a fixed bed of catalyst.

[0059] In the case of purified hydrogen products, the synthesis gas separation operation may include a regenerative hydrogen separation step that can utilize, for example, (i) an adsorbent in the case of separation by PSA, or (ii) a membrane. A combination of such steps may be used in a given synthesis gas separation operation. In any such operation, a gaseous separation byproduct is also provided, generally enriched in the non-hydrogen components of the synthesis gas, such as CO, CO2, and / or H2O. This byproduct may be, for example, a PSA tail gas, or otherwise, depending on the specific membrane used and, as a result, whether the regenerative hydrogen separation product is recovered as a membrane retainate or membrane permeate. This hydrogen obtained by utilizing a synthesis gas separation operation downstream of the WGS operation may, in some embodiments, be characterized as high-purity hydrogen (having a purity of at least about 99 mol%, such as at least 99.9 mol%, or at least 99.99 mol%).

[0060] Further exemplary embodiments of the gasification process Figure 1 illustrates an example of one embodiment of the process, including the operations described above, and depicts a flow chart that further utilizes a washing operation to generate ammoniacal aqueous products. Referring to Figure 1 and with the understanding that the embodiments disclosed herein do not necessarily require all the features illustrated, these embodiments may generally relate to a process for gasifying carbonaceous feed (e.g., wood). The process may include, in a gasifier 50, contacting a carbonaceous feed 10 (which may be dried carbonaceous feed after drying) with an oxygen-containing gasifier feed 14 (and optionally, a separate steam source) under gasification conditions to provide an unwashed gasifier wastewater containing H2, CO, and water-soluble contaminants. The oxygen-containing gasifier feed 14 may contain, alone (or optionally in combination with a separate steam source) H2O and O2, and optionally, CO2, in a total concentration of at least about 90 mol%, at least about 95 mol%, or at least about 99 mol%. Unwashed gasifier wastewater can be any process flow downstream of the gasifier 50 and upstream of the washing operation 80, and may include raw gasifier wastewater 16, tar-depleted gasifier wastewater 18, quenched gasifier wastewater 22, cooled gasifier wastewater 24, filtered gasifier wastewater 26, or washing feed 28.

[0061] The process may further include, for example, supplying at least a portion of the unwashed gasifier wastewater to the washing operation 80 as a washing device feed 28 to remove at least a portion of water-soluble contaminants and provide washed gasifier wastewater 30. If a washing device feed cooler 75 is not present, the washing device feed may correspond to or include filtered gasifier wastewater 26, which may be supplied directly to the washing operation 80. If a washing device feed cooler 75 is used, the unwashed gasifier wastewater, or a portion thereof, may be supplied to the cooler 75 as, for example, filtered gasifier wastewater / heated washing device feed 26. In some embodiments, the cooler 75 may provide vapor generation from the heat in this heated washing device feed and may also provide the washing device feed 28 (which may also be referred to as a cooled washing device feed in such embodiments). Therefore, it can be understood that either or both of the heated cleaning feed 26 and cleaning feed 28 may correspond to or include uncleaned gasifier wastewater, such as in certain cases of uncleaned gasifier wastewater where the uncleaned gasifier wastewater is at a higher temperature than the uncleaned gasifier wastewater as a heated cleaning feed. The uncleaned gasifier wastewater as heated cleaning feed 26 and cleaning feed 28 may have the same composition.

[0062] In exemplary embodiments, uncleaned gasifier wastewater, optionally supplied to the cooler 75 as heated cleaning feed 26 or directly to the cleaning operation 80 as cleaned feed 28, may be filtered gasifier wastewater, which is subjected to a filtration operation 70 as an intervening operation for removing solid particles. More specifically, in addition to being subjected to the filtration operation 70, the filtered gasifier wastewater may be further subjected to one or more other intervening operations downstream of the gasifier 50 and upstream of the filtration operation 70. For example, such intervening operations may include one or more of the following: (i) a tar removal operation 55 for removing at least a portion of the tar in the gasifier wastewater (and providing, for example, tar-depleted gasifier wastewater 18); (ii) a quenching operation 60 which includes direct contact with quenched water 20 (and providing, for example, quenched gasifier wastewater 22); and (iii) a radiant synthesis gas cooler 65 (RSC) or a convection synthesis gas cooler (CSC) 65 which perform heat exchange contact with RSC feed water or CSC feed water, respectively (and provide, for example, cooled gasifier wastewater 24). Optionally, in combination with any of these specific intervening operations, other intervening operations downstream of this operation may include both a filtration operation 70 and a washing device feed cooler 75. In this case, according to any exemplary process as described herein, the uncleaned gasifier wastewater, at least in part, supplied to the cleaning operation 80 as a cleaning device feed, may be filtered and cooled gasifier wastewater, which is subjected to a filtration operation 70 to remove solid particles and is also supplied to a cleaning device feed cooler 75.

[0063] In achieving the various benefits and advantages described herein, a typical process may include recovering the ammonia-water product 34 from the washing operation 80 following at least a first washing device contact step. Alternatively, a typical process may include recovering both the ammonia-water product 34 and the chloride-enriched aqueous product from the washing operation 80 in this manner. The latter product may typically be the aqueous product of the first washing device contact step, providing a first-step overhead product vapor (either inside or outside the washing device vessel) that operates under conditions favorable for preferential dissolution of chlorides to ammonia and is substantially depleted of chlorides other than ammonia and other water-soluble contaminants. Conditions favorable for preferential dissolution of chlorides to ammonia may include a higher temperature in the first washing device contact step compared to an internal second washing device contact step or a higher washing device contact step, or alternatively, compared to an external vapor-liquid separator.

[0064] In this regard, Figures 2 and 3 illustrate additional details regarding the flow of various aqueous feeds and product streams to and from the cleaning operation 80, their boundaries indicated by dashed lines. According to the embodiment illustrated in Figure 2, “at least the first cleaning device contact stage” includes both the first cleaning device contact stage (or the first stage cleaning device) 80a and the second cleaning device contact stage (or the second stage cleaning device) 80b. The second cleaning device contact stage 80b further contacts and purifies the first stage overhead product of the first cleaning device contact stage 80a and can pass upward through a container in which both cleaning device contact stages 80a and 80b are arranged (for example, vertically aligned). The first cleaning device contact stage 80a and the second cleaning device contact stage 80b can be bounded at least partially (for example, according to their upper boundaries) by an axial height into which separate first-stage aqueous cleaning device feeds 101 and second-stage aqueous cleaning device feeds 201 are introduced into such containers.

[0065] In the embodiment illustrated in Figure 2, the aqueous ammonia product 34 is recovered as part of, or including in, the second-stage aqueous washing device feed 201, and optionally followed by cooling by the second-stage aqueous recycling loop cooler 2001. The second-stage aqueous washing device feed 201 is fed into the second washing device contact stage 80b. Withdrawal or "blowdown" of the aqueous ammonia product 34 can be controlled by a recycled aqueous ammonia product (AWP) level or flow control valve 2003, which is used to adjust the operation of the second washing device contact stage 80b with respect to, for example, the liquid level at the bottom of this stage (e.g., present on a porous tray). In this embodiment, the ammonia water product 34 may be drawn from a second-stage aqueous recycling loop including a second-stage aqueous washing device feed 201, the temperature in this second-stage aqueous recycling loop being controlled by specific operation of a washing device vessel, in which the first washing device contact stage 80a and the second washing device contact stage 80b are located. This temperature may also be regulated to some extent using a second-stage aqueous recycling loop cooler 2001, which may be any preferred form such as a cooling tower or an air fan cooler. In an exemplary embodiment, the liquid temperature in the second-stage aqueous recycling loop may be in the range of about 52°C (125°F) to about 177°C (350°F), such as about 66°C (150°F) to about 149°C (300°F), directly upstream of the second-stage aqueous recycling loop cooler 2001. Directly downstream of the second-stage aqueous recycling loop cooler 2001, the liquid temperature can be in the range of approximately 24°C (75°F) to approximately 49°C (120°F), such as approximately 32°C (90°F) to approximately 43°C (110°F).

[0066] Those skilled in the art and familiar with the present disclosure will understand that in further similar embodiments, the ammoniacal aqueous product may be recovered as part of higher washing device contact stages (e.g., a third washing device contact stage, a fourth washing device contact stage, etc.), and similarly, these stages may be bounded by the axial height of the input of each aqueous washing device feed. Furthermore, according to the embodiment illustrated in Figure 3, it will be understood that the first-stage overhead steam-liquid separator 1002 effectively implements the second washing device contact stage outside the washing device container in which the first washing device contact stage 80a is located. In this embodiment, following the first washing device contact stage 80a, which may be the only washing device contact stage occurring inside the washing device container, the ammoniacal aqueous product 34 is recovered as the liquid phase of a steam-liquid separator, which in this embodiment is the first-stage overhead steam-liquid separator 1002. This steam-liquid separator 1002 can ideally effectively implement a single theoretical steam-liquid equilibrium contact plate. However, more generally, as illustrated in Figure 2, the first cleaning device contact stage 80a and the second cleaning device contact stage 80b, as well as any higher cleaning device contact stages, may implement one or more theoretical vapor-liquid equilibrium contact plates.

[0067] Accordingly, Figures 2 and 3 illustrate an embodiment in which the ammonia water product 34 is condensed from the first-stage overhead vapor product exiting the first washing device contact stage. According to the embodiment illustrated in Figure 3 (and unlike the embodiment illustrated in Figure 3), the first-stage overhead vapor product 301 exits the washing device container in which the first washing device contact stage 80a is located, and the washing device container in such an embodiment does not house a second washing device contact stage. More specifically as illustrated in Figure 3, the first-stage overhead product 301 is cooled by the first-stage overhead condenser 3001 to condense the liquid before separating the liquid from the washed gasifier waste liquid 30 and recovering the ammonia water product 34 from at least a portion of the separated liquid. According to this embodiment, the aqueous ammonia product 34 may be recovered as a pure product, and its withdrawal or "blowdown" may be controlled by a flow control valve 3003 used to adjust the recovery and removal of the condensed liquid product with respect to the condensed aqueous ammonia product (AWP) level, or, for example, the liquid level in the first-stage overhead condenser 3001. The first-stage overhead condenser 3001 may be any preferred form, such as a cooling tower or an air fan cooler, and may be used at least to some extent to regulate the temperature of the first-stage overhead product vapor 301, the washed gasifier waste liquid 30, and / or the aqueous ammonia product 34. In an exemplary embodiment, the temperature of the first-stage overhead product vapor 301 upstream of this condenser may be in the range of about 52°C (125°F) to about 177°C (350°F), such as about 66°C (150°F) to about 149°C (300°F). The temperature of the washed gasifier wastewater 30 and the aqueous ammonia product 34 downstream of this condenser and following the separation in the first stage overhead steam-liquid separator may be in the range of about 24°C (75°F) to about 49°C (120°F), such as about 32°C (90°F) to about 43°C (110°F), or in other preferred temperature ranges of the washed gasifier wastewater as described above.

[0068] Figures 2 and 3 illustrate a specific embodiment for performing a cleaning operation 80 (for example, according to the process illustrated in Figure 1), where the flow of the cleaning device feed 28 and cleaning device makeup water 32, also shown in Figure 1, enters the boundary of this operation, and the flow of the cleaned gasifier wastewater 30 and ammonia water products 34, also shown in Figure 1, exits the boundary of this operation. The boundary of the cleaning operation 80 in Figures 2 and 3 is indicated by a dashed line. As further illustrated in these figures, a typical process may also include drawing out a first-stage purge 33 enriched with chloride, which thereby serves to remove the majority of these contaminants present in and entering the cleaning operation 80 together with the cleaning device feed 28. More specifically, the first-stage purge 33 may be enriched with chloride, for example, having a higher total chloride concentration with respect to the cleaning device feed 28. The first stage purge, in which all or part of this total chloride may be in the form of HCl and therefore may contain all or substantially all of the chloride present in the washing device feed, is generally acidic. A typical process may therefore involve drawing the first stage purge from a first stage aqueous recycling loop, which includes the first stage aqueous washing device feed that is introduced into the first washing device contact stage. As illustrated in Figures 2 and 3, washing device makeup water 32 may be added to the first stage aqueous recycling loop. According to various embodiments, including those specifically illustrated in Figures 2 and 3, at least a portion of the ammonia water product may be recycled to the first washing device contact stage, for example, by being added to the first stage washing device feed that is introduced into the first washing device contact stage (e.g., by being added to the first stage aqueous recycling loop, which includes the first stage aqueous washing device feed). For example, Figure 3 illustrates an optional recycled portion 341 of the ammonia water product 34, which is recycled to the first washing device contact stage 80a by being added to the first washing device feed 101 or the first aqueous recycling loop containing this feed.

[0069] Aquatic ammonia products are generally basic and, in terms of having undergone at least a first washing device contact stage, are also "clean" products from which various acidic contaminants such as chlorides have been removed. Aquatic ammonia products contain ammonia derived from nitrogen present in the carbonaceous feed (e.g., wood), and therefore the ammonia concentration and pH of this product may depend, at least to some extent, on the nitrogen content of the feed. Such nitrogen content can vary considerably, for example, in the range of about 0.1% to about 1.5% by weight, or about 0.3% to about 1% by weight. In typical embodiments, aquatic ammonia products may have a pH of at least about 7.5 (for example, in the range of about 7.5 to about 11, such as about 7.5 to about 8.5). From the standpoint of its alkalinity and overall quality (e.g., purity), aqueous ammonia products can be advantageously used directly within a process, such as by being added directly to the process flow or operation to meet process requirements, particularly those requiring separate external resources / utilities such as high-quality makeup water (e.g., boiler feedwater). For example, aqueous ammonia products can be added to one or more intervening operations as described herein, such as when at least a portion of the product is added to a quenching operation to provide all or at least a portion of the quenching water required for that operation. In these and other embodiments in which at least a portion of the aqueous ammonia product is used directly within the process, the product can be used, more specifically, for neutralization (e.g., reaction with chlorides in the form of HCl to reduce or eliminate acidity) from the standpoint of its alkalinity.

[0070] With regard to the use of the ammonia water product in a process, the particular embodiment of the subject involves adding at least a portion of the product to the process sump, the process slag water system, and / or the process cooler. For example, as illustrated in Figure 1, a typical process may involve adding all or a portion of the ammonia water product 34 for one or more of these uses. According to a typical process, (i) at least a portion, such as a first portion 34a of the ammonia water product 34, is added to a radiant synthesis gas cooler (RSC) sump 65a or RSC slag water system 65b (for example, when the RSC slag water system 65b interfaces with the RSC sump 65a), or otherwise to a convection synthesis gas cooler (CSC) sump 65a or CSC slag water system 65b (for example, when the CSC slag water system 65b interfaces with the CSC sump 65a). (ii) At least a portion of the ammonia water product 34, such as the second portion 34b, may be added to the quenching sump 60a or the quenching slag water system 60b (for example, when the quenching slag water system 60b interfaces with the quenching sump 60a), and / or at least a portion of the ammonia water product 34, such as the third portion 34c, may be added to the quenching 60, for example, to provide all or at least a portion of the quenched water 20 supplied to the quenching 60.

[0071] Regarding various characteristics of a typical process, the as-is gasifier wastewater 16 generated in the gasifier 50 is supplied to a tar removal operation 55 to provide tar-depleted gasifier wastewater 18 having a smaller amount of tar than the as-is gasifier wastewater 16. Generally, the process involves recovering synthesis gas products from the tar-depleted gasifier wastewater 16, such synthesis gas products may include any of those downstream of the tar-depleted gasifier wastewater 16, as illustrated in Figure 1. For example, the synthesis gas products may be recovered as aqueous gas shift (WGS) products 36 in a WGS operation 90, which optionally follows one or more intervening operations performed on the gasifier wastewater downstream of the tar removal operation and upstream of the WGS operation. Such intervening operations may include one or more of the following: (i) a quenching operation 60, which involves direct contact between the gasifier wastewater and the quenched water 20; (ii) a radiant synthesis gas cooler (RSC) 65 or a convection synthesis gas cooler (CSC) 65, which may optionally perform heat exchange contact between the gasifier wastewater and RSC feed water or CSC feed water; (iii) a filtration operation 70 for removing solid particulate matter from the gasifier wastewater; (iv) a cleaning device feed cooler 75 for further removing heat from the gasifier wastewater and controlling the temperature of downstream cleaning operations, as described herein; and (v) a cleaning operation 80 for removing water-soluble contaminants from the gasifier wastewater.

[0072] As illustrated more specifically in Figure 1, a typical process involves a quenching operation 60, more specifically a partial dry quenching (PDQ) operation, which includes bringing the tar-depleted gasifier wastewater 18 into contact with quenching water 20 (e.g., by direct contact), where the quenching water 20 may contain at least a portion 34c of the aqueous ammonia product 34. The quenching operation provides a quenched gasifier wastewater 22 having a temperature lower than that of the tar-depleted gasifier wastewater 18. The process may further include cooling the quenched gasifier wastewater 22 in a radiant synthesis gas cooler (RSC) 65 or a convection synthesis gas cooler (CSC) 65, such as by indirect heat exchange contact with RSC feed water or CSC feed water, respectively. This provides cooled gasification waste liquid 24 which can then be subjected to a filtration operation 70, heat removal in a washing device feed cooler 75, and a washing operation 80. Specific details of these operations are described herein, and optionally, the washing operation 80 is illustrated in Figures 2 and 3. By supplying at least a portion of the cleaned gasifier waste liquid 30 provided from the washing operation 80 to the WGS operation 90, a WGS product 36 is provided, which has an increased H2:CO molar ratio compared to the synthesis gas produced by any intervening operation, such as the raw gasifier waste liquid 16 and / or the tar-depleted gasifier waste liquid 18, the quenched gasifier waste liquid 22, the cooled gasifier waste liquid 24, the filtered gasifier waste liquid 26 coming out of the filtration operation 70, the washing feed 28 to the washing operation 80, or the cleaned gasifier waste liquid 30 coming out of the washing operation 80.

[0073] A typical process may further include supplying at least a portion of the WGS product 36 to a synthesis gas conversion operation 95 or a synthesis gas separation operation 95 to provide a regenerative synthesis gas conversion product 40 or a regenerative synthesis gas separation product 40, respectively. According to a more specific embodiment, for example, (i) the synthesis gas conversion operation 95 may include a Fischer-Tropsch reaction step, thereby the regenerative synthesis gas conversion product 40 may include liquid hydrocarbons and / or oxygen-containing compounds with different carbon numbers (e.g., alcohols); (ii) the synthesis gas conversion operation 95 may include a catalytic methanol synthesis reaction step, thereby the regenerative synthesis gas conversion product 40 may include methanol; or (iii) the synthesis gas conversion operation 95 may include a catalytic methanation reaction step, thereby the regenerative synthesis gas conversion product 40 may include RNG. According to another more specific embodiment, the synthesis gas separation operation 95 may include a regenerative hydrogen separation step, thereby the regenerative synthesis gas separation product 40 may include purified hydrogen.

[0074] Overall, aspects of the present invention relate to a gasification process that performs a cleaning operation in which an aqueous ammonia product is recovered, for example, by condensation from the overhead vapor product of the first contact step, following at least a first cleaning device contact step. The overhead vapor product may be inside or outside the cleaning device container in which the first cleaning device contact step is located, for example, the product may be outside the cleaning device container in which only the first cleaning device contact step is located, or inside the cleaning device container in which both the first and second cleaning device contact steps are located, with each contact step supplied by its respective aqueous cleaning device feed. Due to its overall quality and alkalinity, the aqueous ammonia product may be advantageously utilized to satisfy the requirements of the operation in the process, in particular the requirements of the operation in which neutralization may be beneficial. A person skilled in the art who is familiar with the present disclosure 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. Thus, it should be understood that the features of this disclosure are subject to modification and / or substitution, and the specific embodiments described herein are for illustrative purposes only and do not limit the invention as described in the appended claims.

Claims

1. A process for gasifying carbonaceous feed, In the gasification apparatus, under gasification conditions, the carbonaceous feed is brought into contact with the oxygen-containing gasification apparatus feed, H ２ To provide unwashed gasification equipment wastewater containing CO and water-soluble contaminants, To supply at least a portion of the unwashed gasification wastewater as a feed for the washing device to the washing operation, thereby removing at least a portion of the water-soluble contaminants and providing washed gasification wastewater. A process comprising recovering ammonia-derived aqueous products from the cleaning operation, following at least a first cleaning device contact step.

2. The above-mentioned at least first cleaning device contact step includes both the first cleaning device contact step and the second cleaning device contact step, The process according to claim 1, wherein the ammonia-derived aqueous product is recovered as part of a second-stage aqueous washing device feed that is introduced into the second washing device contact stage.

3. The process according to claim 1 or 2, wherein the ammonia-derived aqueous product is recovered as the liquid phase of a steam-liquid separator for separating the overhead steam product of the first step of the first washing device contact step.

4. The process according to any one of claims 1 to 3, wherein the at least first cleaning device contact step involves one or more theoretical steam-liquid equilibrium contact plates.

5. The process according to any one of claims 1 to 4, wherein at least a portion of the ammonia-derived aqueous product is added to a first-stage aqueous washing device feed that is introduced into the first washing device contact stage.

6. The process according to any one of claims 1 to 5, further comprising drawing a chloride-enriched first-stage purge from a first-stage aqueous recycling loop, which includes a first-stage aqueous cleaning device feed introduced into the first cleaning device contact step.

7. The process according to any one of claims 1 to 6, wherein the ammoniacal product has a pH of at least about 7.

5.

8. The process according to any one of claims 1 to 7, wherein at least a portion of the ammonia-derived aqueous product is directly utilized in the process.

9. The process according to claim 8, wherein at least a portion of the ammonia-derived aqueous product is used for neutralization.

10. The process according to claim 8 or 9, wherein at least a portion of the ammonia water product is added to the process sump, the process slag water system, and / or the process cooler.

11. At least a first portion of the ammonia water product is added to a radial synthesis gas cooler (RSC) sump, an RSC slag water system, a convection synthesis gas cooler (CSC) sump, or a CSC slag water system. At least a second portion of the ammonia water product is added to a quenching sump or quenching slag water system, and / or The process according to any one of claims 8 to 10, wherein at least a third portion of the ammonia-derived aqueous product is added to the quenching operation.

12. At least a portion of the cleaned gasification wastewater is supplied to the water-gas shift (WGS) operation, and the H of the cleaned gasification wastewater is used. ２ : Increased H relative to the CO molar ratio ２ The process according to any one of claims 1 to 11, further comprising providing a WGS product having a CO molar ratio.

13. A process for gasifying carbonaceous feed, In the gasification apparatus, under gasification conditions, the carbonaceous feed is brought into contact with the oxygen-containing gasification apparatus feed, H ２ To provide unwashed gasification equipment wastewater containing CO and water-soluble contaminants, Optionally, following one or more intervening operations downstream of the gasifier, at least a portion of the unwashed gasifier wastewater is supplied to the washing operation as a washing device feed to remove at least a portion of the water-soluble contaminants and to provide washed gasifier wastewater. A process comprising recovering ammonia-derived aqueous products and chloride-enriched aqueous products from the washing operation.

14. The process according to claim 13, wherein the ammonia-derived aqueous product includes ammonia derived from nitrogen present in the carbonaceous feed.

15. The process according to claim 13 or 14, wherein the ammonia-derived aqueous product is added to one or more intervening operations.

16. The one or more intervening operations include a filtering operation. The process according to any one of claims 13 to 15, wherein the unwashed gasification wastewater is filtered gasification wastewater that has been subjected to the filtration operation to remove solid particles.

17. The one or more intervening operations include the filtration operation and further include a washing device feed cooler downstream of the filtration operation, The process according to claim 16, wherein the unwashed gasification wastewater is filtered and cooled gasification wastewater that has been subjected to the filtration operation for removing solid particles and to the washing device feed cooler.

18. The process according to claim 16 or 17, wherein the filtered gasification wastewater is subjected to one or more further intervening operations downstream of the gasification and upstream of the filtration operation, the one or more further intervening operations being selected from the group consisting of a radiant synthesis gas cooler (RSC) or a convection synthesis gas cooler (CSC) performing (i) a tar removal operation to remove at least a portion of the gasification wastewater tar, (ii) a quenching operation including direct contact with quenching water, and (iii) heat exchange contact with RSC feed water or CSC feed water.

19. At least a portion of the cleaned gasification wastewater is supplied to the water-gas shift (WGS) operation, and the H of the cleaned gasification wastewater is used. ２ : Increased H relative to the CO molar ratio ２ The process according to any one of claims 13 to 18, further comprising providing a WGS product having a CO molar ratio.

20. The process according to claim 19, further comprising supplying at least a portion of the WGS product to (i) a synthesis gas conversion operation for providing a renewable synthesis gas conversion product, or (ii) a synthesis gas separation operation for providing a renewable synthesis gas separation product.

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