Abstract: The invention relates to the removal of acid compounds from a gaseous effluent In an absorption method using an aqueous solution comprising a tertiary amine or a sterically hindered amine in admixture with a primary or secondary amine meeting the general formula as follows: The invention is advantageously applied to the treatment of natural gas and of gas of industrial origin.

Abstract: A device and a method for producing a fine liquid mist and injecting the said mist into a gas stream to capture and remove very fine particulate pollutants. The pressurized gas stream is passed into a droplet generator (20) into which the liquid is sprayed and atomised into a mist which captures particulates and then into a droplet separator (30) to produce a separated liquid/particulate mixture and a gas stream with a reduced concentration of particulates. The main application is the removal of fine particulates from vehicle exhaust streams. Optionally a degassing stage (90) is provided for the removal of residual gases and vapours. The preferred liquid to form the mist is water.

Abstract: A method of sequestering a multi-element gas emitted by an industrial plant is described herein, the method comprising: contacting a solution, including a first reactant comprising a multi-element gas emitted by an industrial plant and at least one gas absorber comprising nitrogen, for example ammonia or an amine, with a solid, including a second reactant, under conditions that promote a reaction between the first reactant and the second reactant to provide a first product, which incorporates one or more elements of the multi-element gas, thereby sequestering the multi-element gas.

Abstract: Compositions and associated methods directed to the removal of sulfurous compounds from air are presented herein. The compositions and methods may be able to treat air with H2S concentrations of at least 1000 ppm. The compositions and associated methods are used to remove sulfurous compounds from air associated with wastewater systems in various aspects.

Abstract: Apparatus comprising an absorber device provided with a plurality of sequentially adjacent sections for flowing a gas stream therethrough. A solvent reactable with components of the gas stream is ingressed into and egressed from each section of the absorber device by a conduit infrastructure. The conduit infrastructure has a plurality of heat exchange and cooling equipment, and communicates with solvent recovery and regeneration equipment. A process wherein a liquid solvent selected for reacting with gaseous components, is counter-flowed against the gas stream. The liquid solvent temperature is controllably manipulated between each section of the absorber device to provide: (a) thermodynamic-driven mass transfer at the front end of the absorber device, and (b) kinetic-driven mass transfer at the back end of the absorber device. Heat generated during recovery of gaseous components from the liquid solvent is recovered for use in regenerating the solvent system.

Abstract: Novel solvent composition for selective removal of COS from a gas stream containing same, said composition comprising a) at least one polyalkylene glycol alkyl ether of the formula (I) or 1,3-dimethyl-3,4,5,6-tetrahydro-2(1H)-pyrimidinone or a mixture of N-formylmorpholine and N-acetylmorpholine Wherein R1 is an alkyl group having from 1 to 6 carbon atoms; R2 is hydrogen or an alkyl group having from 1 to 4 carbon atoms; Alk is an alkylene group, branched or unbranched, having from 2 to 4 carbon atoms, and n is from 1 to 10; and b) at least one alkanolamine compound of the formula (II) or at least one piperazine compound of formula (III) wherein R3 is hydrogen, an alkyl group having from 1 to 6 carbon atoms, or the R4OH group; R4 is a branched or unbranched alkylene group having from 1 to 6 carbon atoms; R5, independently in each occurrence, is hydrogen or an hydroxyalkyl group having from 1 to 4 carbon atoms; and R6 is hydrogen, an alkyl group having from 1 to 6 carbon atoms or an hydroxyalkyl group having f

Abstract: An process for efficiently deacidizing a gaseous mixture is described. The process utilizes a self-concentrating absorbent that absorbs an acid gas at reduced overall energy costs for the deacidizing operation.

Abstract: A process for the removal of an amine capturable gas from a feed gas stream using an amine solvent, the process comprises (a) contacting the feed gas stream with a lean amine solvent to form a rich amine solvent, wherein heat stable salts are present in the rich amine solvent; (b) stripping amine capturable gas from the rich amine solvent to form the lean amine solvent and an overhead reflux stream; (c) periodically contacting at least a portion of one or both of the lean amine solvent and the rich amine solvent with an anion exchange resin to form a first heat stable salt lean amine solvent; (d) periodically regenerating the anion exchange resin, wherein during the regeneration of the anion exchange resin, at least a portion of the reflux stream is used to wash the amine solvent from the anion exchange resin to produce a second heat stable salt lean amine solvent; and, (e) recycling at least a portion of the first and the second heat stable salt lean amine solvent for use in capturing the amine capturable ga

Abstract: The present invention relates to a method for separation and recycling of pure sulfur dioxide from a gaseous mixture in the IS cycle. More specifically, the present invention relates to a method for separation and recycling of pure sulfur dioxide from a gaseous mixture in the IS cycle using an ionic liquid under a specific condition. When compared with the conventional amine-based absorbent, the use of the ionic liquid enables continuous absorption and stripping of SO2 even at high temperature, and enables a reversible absorption of SO2 without loss, decomposition or degradation of a solvent due to good chemical stability, thereby enabling separation and recycling of pure SO2 from a gaseous mixture in the IS cycle.

Abstract: An improved process for deacidizing a gaseous mixture using phase enhanced gas-liquid absorption is described. The process utilizes a multiphasic absorbent that absorbs an acid gas at increased rate and leads to reduced overall energy costs for the deacidizing operation.

Abstract: An additive and method of use for treating flue gas of a coke-fired cupola following removal of the blast air during shutdown to adjust the charge and reduce acid buildup in the condensate and corrosion in downstream equipment by injecting into the flue gas a finely divided spray comprising an additive containing a volatile amine mixed with an antistatic agent that creates a positive static charge in the additive, and elevates the pH of the condensate by reducing the formation of sulfuric acid from entrained sulfur-containing compounds.

Abstract: Apparatus comprising an absorber device provided with a plurality of sequentially adjacent sections for flowing a gas stream therethrough. A conduit infrastructure comprising a section configured to ingress, communicate with and egress from each section of the absorber device, and a recovery and regeneration section, is configured with a plurality of heat exchange and cooling equipment. A process wherein a liquid solvent provided with at least one chemical compound selected for reacting with the selected gaseous component, is counter-flowed against and commingled with the gas stream. The liquid solvent temperature is controllably manipulated between each section of the column to provide: (a) thermodynamic-driven mass transfer at the front end of the absorber device, and (b) kinetic-driven mass transfer at the back end of the absorber device. The heat generated during the recovery of the gaseous component from the absorption liquid solvent system is recovered for use in regenerating solvent system.

Abstract: An process for efficiently deacidizing a gaseous mixture is described. The process utilizes a self-concentrating absorbent that absorbs an acid gas at reduced overall energy costs for the deacidizing operation.

Abstract: The invention provides a process for the removal of polysulfanes from gas streams formed during H2S synthesis.

Abstract: A method of deacidizing a gaseous effluent including acid compounds includes the following stages: a) contacting the gaseous effluent with a first fraction of an absorbent solution containing reactive compounds with at least two amine functions, so as to obtain a gaseous effluent depleted in acid compounds and a liquid effluent laden with acid compounds, b) contacting the liquid effluent obtained in stage a) with a second fraction of absorbent solution laden with molecules more acid than the acid compounds, so as to cause formation of a first liquid phase depleted in acid compounds and a second liquid phase enriched in acid compounds and laden with more acid molecules, c) separating the first phase from the second phase, and d) regenerating the second phase so as to release a gas stream rich in acid compounds and a liquid stream poor in acid compounds and laden with more acid molecules.

Abstract: An additive and method of use for treating flue gas of a coke-fired cupola following removal of the blast air during shutdown to adjust the charge and reduce acid buildup in the condensate and corrosion in downstream equipment by injecting into the flue gas a finely divided spray comprising an additive containing a volatile amine mixed with an antistatic agent that creates a positive static charge in the additive, and elevates the pH of the condensate by reducing the formation of sulfuric acid from entrained sulfur-containing compounds.

Abstract: The present invention is directed to an improved method and system for separating and purifying gas using gas-liquid absorption. According to this invention, the method is carried out in an absorber, where a liquid absorbent, a gas mixture containing a gas to be absorbed were introduced from an inlet. During absorption, the second liquid phase was separated out from the absorbent. The absorbed gas was accumulated in one of liquid phases. After absorption, two liquid phases were separated. One of the liquids with rich absorbed gas was forward to regenerator. After regeneration, the liquid was cycled back to absorber. The liquid phase with lean absorbed gas was back to absorber directly to complete the cycle.

Abstract: A method is provided for removing acid gases and ammonia from a fluid stream in which a fluid stream comprising acid gases and ammonia is brought into contact with an aqueous absorption medium. The fluid stream is depleted of acid gases and ammonia and the absorption medium stream, which is charged with acid gases and ammonia, is regenerated in a desorption step. The acid gases and the ammonia are stripped out of the absorption medium and the condensable fractions thereof are condensed. A condensate and also a purified absorption medium stream are obtained. The condensate is ejected in part or completely from the desorption step, or feed in part or completely to a distillation column in which ammonia is separated off overhead as an aqueous solution or in the pure state. A aqueous bottom stream is obtained which is recycled to the absorption step or the desorption step.

Abstract: A method for obtaining an acid gas stream having a pressure of from 3 to 30 bar by removal of acid gases from a fluid stream containing H2S, the molar fraction of H2S based on the total amount of acid gases being at least 50 mol %, the method comprising bringing the fluid stream into intimate contact with a liquid absorption medium, thus producing a fluid stream substantially freed from acid gases and an acid-gas-loaded liquid absorption medium; separating the fluid stream and the liquid absorption medium; separating, by heating and optionally by expansion or stripping, the liquid absorption medium into an acid gas stream and a regenerated liquid absorption medium; passing the regenerated liquid absorption medium into a heat exchanger and cooling it there by using part of its thermal energy to heat up the acid-gas-loaded liquid absorption medium; and recirculating the regenerated liquid absorption medium.

Abstract: Selective, irreversible removal of hydrogen sulfide (H2S) and other sulfhydryl compounds from a gas stream, such as sour natural gas and sour hydrocarbon liquids is achieved with a scavenging agent having hydroxyalkyl functionality and alkylamine functionality. This scavenger possesses a higher capacity for H2S removal compared with a scavenger having only hydroxyalkyl functionality. The scavenging agent is made by reacting at least one alkanolamine and at least one alkyl amine with an aldehyde, such as formaldehyde.

Abstract: A process for the removal of hydrogen sulfide and mercaptans from a gas stream containing a high ratio of mercaptans to hydrogen sulfide, wherein the first step removes hydrogen sulfide by washing the gas stream with an aqueous washing solution comprising water, a physical solvent and a chemical solvent. The first removal step is followed by a second removal step by which mercaptans are removed from the washed gas stream by means of molecular sieves.

Abstract: The gaseous effluent flowing in through line 1 is contacted in absorption zone ZA with the liquid absorbent solution flowing in through line 9. The gaseous effluent depleted in acid compounds is discharged through line 2. The absorbent solution laden with acid compounds is discharged through line 3. The absorbent solution once laden with acid compounds comprises two phases: a first phase poor in acid compounds and a second phase rich in acid compounds. The two phases are separated in zone ZS. The first phase is recycled through lines 5 and 9 to absorption zone ZA. The second phase is fed through line 4 into regeneration zone ZR. In zone ZR, the acid compounds are separated from the absorbent solution. The acid compounds are discharged through line 7. The regenerated absorbent solution is recycled through lines 6 and 9 to zone ZA.

Abstract: The invention relates to the use of an absorption liquid for purifying gases from gaseous acidic contaminants, the absorption liquid comprising A) 0.1 to 100% by weight of one or more amines of the formula I where R1 is H, C1-C6-alkyl, an aromatic radical having 6 to 18 carbon atoms or a radical of the formula 2 R2 is H, C1-C6-alkyl, an aromatic radical having 6 to 18 carbon atoms or a radical of the formula 3 R3 is C1-C6-alkyl or an aromatic radical having 6 to 18 carbon atoms R4 is H or CH3 R5 is H or CH3 x is a number from 0 to 3 y is a number from 0 to 3 z is an integer between 1 and 30, and also, if appropriate, B) 0 to 99.9% by weight of water, and/or C) 0 to 99.9% by weight of any desired solvent.

Abstract: A process for removing contaminants from a waste gas stream comprises treating the waste gas stream to remove at least one of SO2 and NOx and to obtain a lean stream having a reduced level of at least one of SO2 and NOx and, contacting the lean gas stream with a mercury absorbent solution comprising permanganate to remove mercury vapour and to obtain a mercury lean stream and a mercury rich absorbent solution. The mercury rich absorbent solution may be subsequently treated on a batch basis to remove precipitated manganese dioxide and obtain a solution containing mercury ions.

Abstract: The disclosure relates to an absorbent for removing acid gases from fluids. The absorbent contains at least one tertiary amine, an amine which is selected from hydroxyethylpiperazine, bis(hydroxyethylpiperazine) or a mixture of these and piperazine. The absorbent may optionally contain a physical solvent for the acid gases.

Abstract: Disclosed is a process for the treatment of gas containing mercaptans and acid gases, including the following steps: (1) separating the acid gases from the said gas and obtaining a sweetened gas and the flow of acid gases containing H2S; (2) reacting the H2S thus obtained in step (1) according to the Claus reaction; (3) concentrating the mercaptans in at least one cut of the said sweetened gas; (4) extracting the mercaptans of the said cut; and further comprising: (5) transforming the mercaptans into dialkyl-disulfide (DSO); (6) hydrogenating DSO into H2S; and (7) reacting the H2S thus obtained at step (6) according to the Claus reaction. An installation for carrying out this procedure is also described.

Abstract: Sulphur dioxide is removed from gas streams by contacting the gas stream with an absorbing medium containing an amine capable of forming an amine salt, heat stable salt and sulfite. The level of heat stable salt is selected such that during the regeneration process of the sulphur dioxide rich amine, the pH of the absorbing medium is at a selected level or below when the level of sulfite in the absorbing medium has been reduced to a specified value. The amine that absorbs the sulphur dioxide has a pKa less than that of sulfite. If the absorbent includes a diamine, then the spent absorbing medium is regenerated under conditions such that at least one amine group remains in salt form.

Abstract: A process for recovering CO2 from a feed gas stream comprises treating the feed gas stream with a regenerated absorbent comprising at least one tertiary amine absorbent having a pKa for the amino function of from about 6.5 to about 9 in the presence of an oxidation inhibitor to obtain a CO2 rich stream and subsequently treating the CO2 rich stream to obtain the regenerated absorbent and a CO2 rich product stream. The feed gas stream may also include SO2 and/or NOx.

Abstract: COS is selectively removed with respect to CO2 from a hydrocarbonaceous fluid stream which contains CO2 and COS. Examples of the fluid stream include a gas stream, for example natural gas, synthesis gas from heavy oil or heavy residues or refinery gas, or from liquid or liquefied hydrocarbons, for example LPG (Liquefied Petroleum Gas) or NGL (Natural Gas Liquids). The process is carried out by (1) intimately contacting the fluid stream in an absorption or extraction zone with a scrubbing liquor consisting of an aqueous amine solution containing from 1.5 to 5 mol/l of an aliphatic alkanolamine having of from 2 to 12 carbon atoms and from 0.8 to 1.7 mol/l of at least one activator selected from the group consisting of piperazine, methyl piperazine and morpholine, (2) removing the COS essentially completely from the fluid stream, and (3) separating the substantially COS-decontaminated fluid stream and the COS-loaded scrubbing liquor and discharging them from the absorption or extraction zone.

Abstract: The present invention provides a mercury removal method which can effectively remove very small amounts of mercury components present in a gas during wet gas purification such as coal or heavy oil gasification gas purification and petroleum refining. A mercury removal method for the removal of mercury present in a gas, the method comprising the steps of bringing a gas containing at least mercury and not less than 10 ppm of hydrogen sulfide into gas-liquid contact with an absorbing fluid under pressurized conditions so as to cause mercury to pass into the absorbing fluid; flashing the mercury-containing absorbing fluid under lower-pressure conditions to separate it into gaseous components and liquid components; and removing the mercury contained in the separated gaseous components by adsorption to an adsorbent.

Abstract: The present invention pertains to a method for controlling the foaming of a waterborne composition or in an industrial process utilizing a waterborne composition by the incorporation of a foam controlling agent in an amount effective for controlling foam. The method comprises utilizing as the foam controlling agent an alkyl glycidyl ether-capped diamine compound of the formula: L is a linker group comprising a linear, branched, or cyclic alkyl group having from 2 to about 6 carbon atoms or an alkyl ether group having from about 4 to about 8 carbon atoms. R is independently selected from hydrogen or —CH2CHOHCH2OR′. R′ is an alkyl group having from about 4 to about 22 carbon atoms. The compound generates an initial foam height at least 30% less than a 0.1 wt % aqueous solution of dioctyl sodium sulfosuccinate (DOSS), when added at 0.1 wt % to the aqueous DOSS solution. The present invention also pertains to an aqueous composition comprising the foam controlling agent.

Abstract: The disclosure concerns a process for removing mercaptans from fluid streams comprising same, especially from hydrocarbon gas streams, for example natural gas, synthesis gas from heavy oil or heavy residues or refinery gas, or else from liquid hydrocarbons, for example LPG (liquefied petroleum gas). The invention comprises intimately contacting the fluid stream in an absorption or extraction zone with a scrubbing liquor comprising at least one aliphatic alkanolamine of 2-12 carbon atoms, the amount of wash liquor being supplied to the absorption or extraction zone being sufficient to remove at least CO2 and H2S essentially completely from the fluid stream, and separating the substantially decontaminated fluid stream and the contaminated wash liquor and discharging them from the absorption zone.

Abstract: Within the scope of a process using two absorption sections for treating a natural gas containing CO2 and/or H2S, as well as mercaptans, COS and/or CS2, the present invention aims to wash the gaseous hydrocarbons desorbed upon expansion of the solvent from the first absorption section with the solvent from the second absorption section.

Abstract: A method for controlling the sulfur dioxide partial pressure in a pressurized, heated, oxygen-containing gas mixture which is contacted with an ion-conducting metallic oxide membrane which permeates oxygen ions. The sulfur dioxide partial pressure in the oxygen-depleted non-permeate gas from the membrane module is maintained below a critical sulfur dioxide partial pressure, pSO2*, to protect the membrane material from reacting with sulfur dioxide and reducing the oxygen flux of the membrane. Each ion-conducting metallic oxide material has a characteristic critical sulfur dioxide partial pressure which is useful in determining the required level of sulfur removal from the feed gas and/or from the fuel gas used in a direct-fired feed gas heater.

Abstract: A cigarette filter having a reagent which chemically reacts with and removes a gaseous component of a smoke stream. The reagent contains functional groups covalently bonded to a non-volatile inorganic substrate which is incorporated in the filter. The filter can remove gaseous components such as aldehydes from tobacco smoke. Preferred functional groups are 3-aminopropylsilyl groups covalently bonded to silica gel (APS silica gel). The reagent can be contained in a space in the filter or incorporated in one or more filter elements such as tipping paper, shaped paper insert, mouthpiece plug, solid filter element, or free-flow filter element. The reagent can be part of or coated on paper such as tipping or filter paper or incorporated in non-paper filter elements formed from fibrous materials such as cellulose acetate or polypropylene fibers. Other preferred reagents include aminoethylaminopropylsilyl (AEAPS) silica gel and aminoethylaminoethylaminopropylsilyl (AEAEAPS) silica gel.

Abstract: A process is provided for the removal of hydrogen sulfide out of a gaseous stream (22), such as a natural gas, by contacting the hydrogen sulfide containing gas with a sorbing liquid (26) containing a tertiary amine so that the hydrogen sulfide is sorbed into the liquid in absorber (11) and transferring the sorbing liquid/hydrogen sulfide mixture to a reactor (15) where the tertiary amine promotes the conversion of the hydrogen sulfide into polysulfide via reaction with sulfur; transferring the polysulfide solution from the reactor (15) to a regenerator (10) where polysulfide is converted into elemental sulfur via reaction with air (9); transferring at least a portion of the solution (25) containing elemental sulfur, as well as sulfate and thiosulfate species, into a mixture (36) where it is contacted with gaseous ammonia which reacts with the sulfate and thiosulfate species to produce ammonium sulfate and ammonium thiosulfate which are removed from the solution while the remaining portion of solution (25) is

Abstract: Porous, preferably dimensionally stable material and a method for using for the removal of gaseous impurities from a gas mixture, such as H2S, COS, CH2, and SO2, into the pores of which there is incorporated a secondary amine which chemically bonds with the constituents to be removed, with the material including a hydrophobic polymer with pores having an average diameter in the range of from 0.1 to 50 &mgr;m and a secondary amine having hydrophobic properties which optionally is incorporated into a hydrophobic liquid is disclosed. Favorable results have been attained using polypropylene as the hydrophobic polymer and ditridecyl amine as the secondary amine, with a tertiary amine, such as C12 to C14-alkyl diethanol amine, being part of the hydrophobic liquid.

Abstract: The invention relates to a method of confining sulfur dioxide for storage or transportation under safe conditions. The method of the invention comprises the steps of (a) contacting a sulfur dioxide-containing gas stream with an absorbing medium comprising water and a water-soluble amine absorbent having at least one amine group with a pKa value greater than about 7 and at least one other amine group with a pKa value less than about 6.5 so that the at least one amine group with a pKa value greater than about 7 irreversibly absorbs sulfur dioxide in salt form rendering the amine absorbent non-volatile and the at least one other amine group with a pKa value less than about 6.5 reversibly absorbs sulfur dioxide, to thereby saturate the absorbing medium with sulfur dioxide against a partial pressure of sulfur dioxide of no more than about 1 atmosphere at 25° C.; and (b) charging the absorbing medium saturated with sulfur dioxide obtained in step (a) into a container for storage or transportation.

Abstract: An absorbent composition for the removal of acid gases, such as CO2, H2S and COS, from gas streams is provided. The absorbent composition comprises an aqueous solution comprising: 1) greater than 1 mole piperazine per liter of aqueous solution; and 2) about 1.5 to about 6 moles methyldiethanolamine per liter of aqueous solution.

Abstract: The present invention relates to the use of an absorption liquid for purifying a gas by removal of gaseous, acidic impurities. The gas to be purified can be any gas, such as synthesis gas or natural gas, which contains gaseous, acidic impurities such as CO2, H2S, SO2, CS2, HCN, COS or mercaptans. The absorption liquid comprises: A) from 0.01 to 4% by weight of at least one compound of the formula B) from 0.001 to 8.0% by weight of water, and C) at least one polyalkylene glycol alkyl ether of the formula R1—O—(R2—O)x—R3 to 100% by weight, where R1 is C1-C4-alkyl, R2 is ethylene or 2-methylethylene, R3 is hydrogen or C1-C4-alkyl, R4 is hydrogen or C1-C4-alkyl, R5 is C1-C4-alkylene and X is an integer from 1 to 10. The amine may be N-methyldiethanolamine and the ether may be polyethylene glycol dimethyl ether.

Abstract: An absorbent composition for purifying gases which contain acidic components. The composition contains at least one compound of formula (I), wherein n is 2-6, p is 1-3, the R1 groups may be the same or different and represent hydrogen or C1-3 alkyl, and R2 is hydrogen, C1-3 alkyl or a group of formula (II). The composition is an aqueous solution of 20-60 w/w %.

Abstract: The present invention relates to an activated metal oxide and methods for removing sulfur compounds from fluids, whereby the activated metal oxide includes an amount of metal oxide and an amount of ethoxylated fatty amine, with the ethoxylated fatty amine increasing the rate of reactivity between the metal oxide and the sulfur compounds, which include hydrogen sulfide, carbonyl sulfide, mercaptans, and other organic sulfides. The ethoxylated tallow amines include ethoxylated tallow amine, ethoxylated cocoa amine, ethoxylated oleic amine, ethoxylated soya amine, ethoxylated palmatic amine, ethoxylated steric amine, and combinations thereof. The method involves activating the metal oxide, preferably iron oxide or zinc oxide, with an amount of ethoxylated fatty amine so that when fluids, such as water or liquid hydrocarbons, contact the metal oxide the sulfur compounds are removed.

Abstract: A cigarette filter having a reagent which chemically reacts with and removes a gaseous component of a smoke stream. The reagent contains functional groups covalently bonded to a non-volatile inorganic substrate which is incorporated in the filter. The filter can remove gaseous components such as aldehydes from tobacco smoke. Preferred functional groups are 3-aminopropylsilyl groups covalently bonded to silica gel (APS silica gel). The reagent can be contained in a space in the filter or incorporated in one or more filter elements such as tipping paper, shaped paper insert, mouthpiece plug, solid filter element, or free-flow filter element. The reagent can be part of or coated on paper such as tipping or filter paper or incorporated in non-paper filter elements formed from fibrous materials such as cellulose acetate or polypropylene fibers.

Abstract: The invention is a process for separating acid gases from synthesis gas and treating the resulting solids. A mixture comprising synthesis gas and acid gas is contacted with a fluid that reacts with said acid gas to form a particulate solid dispersed in a fluid. The slurry comprising fluid and particulate solid is filtered to separate the particulate solid from the fluid by means of a regenerable filter. The particulate solids are removed from the regenerable filter by back-washing with a back-washing fluid to form a pumpable slurry comprising a mixture of particulate solids and back-washing fluid. The slurry is gasified to form synthesis gas and vitrified solids.