Abstract: The present application discloses compositions comprising ionic liquids and an amine compound, and methods for using and producing the same. In some embodiments, the compositions disclosed herein are useful in reducing the amount of impurities in a fluid medium or a solid substrate.

Abstract: With the help of a method of selective removal of hydrogen sulphides, organic sulphur components and CO2 from crude gases, by using a first and second absorption stage (41 or 49) for separating almost pure CO2, a solution has to be found, with which, among other things, hydrogen sulphides and organic sulphur compounds can be removed in as selective a manner as possible. This is achieved as follows: the absorption agent coming out of the first absorption stage (41) and enriched with hydrogen sulphide and CO2 a.o.

Abstract: The invention relates to a method for reducing the carbon dioxide concentration in air of a closed or partially closed unit of space. The inventive method may comprise the steps of removing an air flow from the unit of space, guiding the air flow in a membrane system that may contain at least one membrane module having a CO2/O2 selectivity of greater than 2, removing the carbon dioxide permeated through the membrane, and returning the air flow that has been depleted of carbon dioxide in the membrane system to the unit of space. The inventive method may be optionally combined with an oxygen enrichment method. The invention also relates to corresponding devices for carrying out the inventive method.

Abstract: A gas (1) comprising hydrogen sulfide, carbon dioxide, and hydrocarbon contaminants is treated in a plant (FIG. 2) in a configuration in which waste streams are recycled to extinction. In especially preferred aspects of contemplated methods and configurations, hydrogen sulfide and other sulfurous components are converted to a sulfur product (37), carbon dioxide (44A) is separated at a purity sufficient for enhanced oil recovery or sale, and hydrocarbon contaminants are purified to a marketable hydrocarbon product (49).

Abstract: Compositions and methods related to the removal of acidic gas. In particular, the present disclosure relates to a composition and method for the removal of acidic gas from a gas mixture using a solvent comprising a diamine (e.g., piperazine) and carbon dioxide. One example of a method may involve a method for removing acidic gas comprising contacting a gas mixture having an acidic gas with a solvent, wherein the solvent comprises piperazine in an amount of from about 4 to about 20 moles/kg of water, and carbon dioxide in an amount of from about 0.3 to about 0.

Abstract: The present application includes a method for inhibiting amine degradation during CO2 capture from flue gas streams. Particularly, the present disclosure relates to a method of inhibiting O2- and/or SO2-induced degradation of amines using sodium sulfite (Na2SO3), potassium sodium tartrate tetrahydrate (KNaC4H4O6.4H2O), ethylenediaminetetraacetic acid (EDTA) or hydroxylamine (NH2OH), or analogs or mixtures thereof during CO2 capture by amines.

Abstract: A description is given of a process for removing carbon dioxide from gas streams in which the partial pressure of the carbon dioxide is less than 200 mbar, in particular flue gases, the gas stream being contacted with a liquid absorption medium which comprises an aqueous solution (A) of a tertiary aliphatic alkanolamine and (B) an activator of the formula R1—NH—R2—NH2, where R1 is C1-C6-alkyl and R2 is C2-C6-alkylene, the sum of the concentrations of A and B being 2.5 to 7 mol/l, and the molar ratio of B to A being in the range of 1:3 to 1.5:1. The activator is, for example, 3-methylaminopropylamine, the tertiary aliphatic amine methyldiethanolamine, methyidiisopropanolamine or n-butyldiethanolamine. The process permits substantial removal of carbon dioxide and the regeneration of the absorption medium is possible with relatively low energy consumption.

Abstract: A description is given of an absorption medium for removing carbon dioxide from a gas stream, which comprises an aqueous solution of at least one amine and at least one aminocarboxylic acid and/or aminosulfonic acid. The concomitant use of an aminocarboxylic acid or aminosulfonic acid reduces the energy required for regeneration of the absorption medium.

Abstract: A process for separating the components of a multi-component gas stream is disclosed. The multi-component gas stream is contacted with a solvent in an extractor to produce an overhead stream enriched with unabsorbed component(s) and a rich solvent bottoms stream enriched with absorbed component(s). The rich solvent bottoms stream is then flashed at reduced pressure to regenerate lean solvent and to recover the absorbed component(s) as an overhead stream. The regenerated solvent is recycled to the extractor. A portion of the circulating solvent comprises external solvent added to the system. A second portion of the circulating solvent comprises internal solvent contained in the feed gas.

Abstract: A method for separation of CO2 from the combustion gas from a thermal power plant fired with fossil fuel, wherein the combustion gas from the thermal power plant is used as cooled, compressed and reheated by combustion of natural gas in a combustion chamber to form an exhaust gas, where the exhaust gas is cooled an brought in contact with an absorbent absorbing CO2 from the exhaust gas to form a low CO2 stream and an absorbent with absorbed CO2, and where the low CO2 stream is heated by means of heat exchanges against the hot exhaust gas leaving the combustion chamber before it is expanded in turbines, is described. A plant for performing the method and a combined plant is also described.

Abstract: Methods and systems for handling sour carbon dioxide (CO2) streams are provided. In one aspect, a method for sequestering an emissions-heavy gas includes removing at least a portion of an acid gas from a rich solvent in an acid gas stripper to create the emissions-heavy gas, and channeling the emissions-heavy gas to a storage system.

Abstract: There is disclosed herein a solution for removing a sulphur compound or carbon dioxide from a fluid and methods for its use, said solution comprising sulphuric acid, a metal at between about 0.05 to 10 percent by weight, an amine at between about 10 to 80 percent by volume and water. In one aspect, the sulphuric acid is in the form of a chelating agent and in another it is in the form of a derivative of a sulphur-based acidic compound. The sulphur compound may be hydrogen sulphide, carbonyl sulphide or a mercaptan. In one aspect, the method is practiced at temperatures significantly below zero. In another aspect, this invention is an acid/amine solution comprising sulphuric acid, sulphuric acid in the form of a chelating agent, or a derivative of a sulphur-based acidic compound and monoethanolamine. This solution may be used as a source of monoethanolamine.

Abstract: The natural gas arriving through pipe 1 is deacidified by being brought into contact with a solvent in zone C. The solvent charged with acid compounds is regenerated in zone R. The acid gases, released into pipe 5 upon regeneration, include a quantity of solvent. The method enables the solvent contained in the acid gases to be extracted. In zone ZA, the acid gases are brought into contact with a non-aqueous ionic liquid whose general formula is Q+ A?, where Q+ designates an ammonium, phosphonium, and/or sulfonium cation, and A? designates an anion able to form a liquid salt. The solvent is removed from the acid gases evacuated through pipe 6. The ionic liquid charged with solvent is regenerated by heating in an evaporator DE. The ionic liquid regenerated is recycled through pipes 8 and 9 to zone ZA. The solvent is evacuated through pipe 13.

Abstract: A system for removing carbon dioxide from an atmosphere to reduce global warming including an air extraction system that collects carbon dioxide from the atmosphere through a medium and removes carbon dioxide from the medium; a sequestration system that isolates the removed carbon dioxide to a location for at least one of storage and which can increase availability of renewable energy or non-fuel products such as fertilizers and construction materials; and one or more energy sources that supply process heat to the air extraction system to remove the carbon dioxide from the medium and which can regenerate it for continued use.

Abstract: A method for processing flue-gas, in an exemplary embodiment, includes providing an absorber unit having a membrane contactor, channeling a combustion flue gas along a first surface of the membrane contactor, and channeling an ammonia-based liquid reagent along a second opposing surface of the membrane contactor. The method also includes partially separating the ammonia-based liquid from the flue gas such that the ammonia-based liquid and the flue gas contact at gas-liquid interface areas, defined by a plurality of pores of the membrane contactor, to separate CO2 from the flue gas by a chemical absorption of CO2 within the ammonia-based liquid to produce a CO2-rich ammonia-based liquid.

Abstract: The raw natural gas is deacidized and dehydrated in units DA and DH. The treated gas is then purified by adsorption of the mercaptans in first enclosure A1. Part of the purified gas is heated in E1, then fed into second enclosure A2 so as to discharge the water adsorbed by the adsorbent material contained in this second enclosure. A steam-rich stream is fed into third enclosure A3 containing a mercaptan-laden adsorbent material. In A3, the mercaptans are desorbed and replaced by the steam.

Abstract: A plant includes an absorber (105) that receives a feed gas (10) at a pressure of at least 400 psig and comprising at least 5 mol % carbon dioxide, wherein the absorber (105) is operated at an isothermal or decreasing top-to-bottom thermal gradient, and wherein the absorber (105) employs a physical solvent to at least partially remove an acid gas from the feed gas (10). Such configuration advantageously provide cooling (108) by expansion of the rich solvent (21) generated in the absorber (105), wherein both a semi-rich solvent (13) generated and recycled to the absorber (105) and the feed gas (10) are cooled by expansion of the rich solvent (21).

Abstract: The invention relates to a process for separating NH3 from a mixture containing NH3, CO2 and H2O which comprises an NH3 rectification step carried out in a NH3 separation device to which one or more streams containing NH3, CO2 and H2O including the mixture, are supplied, with a stream consisting substantially of gaseous NH3 being formed in the NH3 separation device, separated from the mixture and discharged. In the process according to the invention a condensation step is carried out on at least one of the stream consisting substantially of gaseous NH3 or the one or more streams containing NH3, CO2 and H2O supplied to the NH3 separation device, in which at least a part of the existing CO2 is converted to a liquid phase.

Abstract: The present invention is directed to an improved integrated process for the removal of heavy hydrocarbons, carbon dioxide, hydrogen sulfide, and water from a raw natural gas feed stream. More specifically, the integrated process of the present invention comprises a three step process involving the adsorption of heavy hydrocarbons and water on an adsorbent bed selective for the same, a subsequent aqueous lean amine treatment for the absorptive removal of acid gases, such as carbon dioxide and hydrogen sulfide, and an adsorptive removal of water. The process of the present invention results in a highly purified dry natural gas product stream.

Abstract: Disclosed is a formulation for the absorption of CO2, which comprises water, at least one CO2 absorption compound and a carbonic anhydrase as an activator to enhance the absorption capacity of the CO2 absorption compound. The invention also concerns the use of carbonic anhydrase, in a CO2 absorption solution to increase the CO2 absorption rate of such solution.

Abstract: The invention relates to a method for the removal of carbon dioxide from a gas flow, in which the partial pressure of the carbon dioxide in the gas flow is less than 200 mbar, whereby the gas flow is brought into contact with a liquid absorption agent, comprising an aqueous solution (A) of a tertiary aliphatic amine and (B) an activator of general formula R1-NH-R2-NH2, where R1=C1-C6 alkyl and R2=C2-C6 alkylene. The method is particularly suitable for treatment of flue gases and also relates to an absorption agent.

Abstract: Processing schemes and arrangements for separating hydrogen sulfide, carbon dioxide and hydrogen from a fluid stream including a solvent-based acid gas separation zone, a membrane separation zone and a pressure swing adsorption unit are provided. At least a portion of a carbon dioxide-lean non-permeate stream produce in the membrane separation zone is recycled to the acid gas separation zone to strip and recover co-absorbed carbon dioxide from the solvent. Recovered carbon dioxide can be beneficially combusted in an associated gas turbine to generate electricity. Additionally, a portion of a pressure swing adsorption tail gas stream and/or a sulfur recovery tail gas stream may also be recycled to the acid gas separation zone for further processing.

Abstract: A method of assembling a gas removal system for an integrated gasification combined cycle is provided. The method includes coupling a first rich solvent tank in flow communication with the integrated gasification combined cycle to store a first emissions-rich solvent discharged from the integrated gasification combined cycle and coupling a first stripper in flow communication with the first rich solvent tank to facilitate removing gases from the first emissions-rich solvent. The method also includes coupling an absorber in flow communication with the first stripper to receive gases from the first stripper and create a second emissions-rich solvent and coupling a second rich solvent tank in flow communication with the absorber to store the second emissions-rich solvent.

Abstract: A system and method for separation of a gas, e.g., carbon dioxide, from a gaseous mixture using a hollow fiber membrane module. The module contains an absorbent solution that is effective in absorbing the gas for an extended period, e.g., eight hours, without regeneration or replacement. The absorbent solution is then regenerated by passing a sweep gas through the hollow fibers in the module. The separation system is particularly useful for fuel cell and battery applications.

Abstract: This invention relates to a method for desalination of seawater (5, 30) and separation of CO2 from exhaust (77) from a gas turbine (7). LNG (4) is fed into a heat exchanger (6) in which it receives heat from seawater (5) and heat from steam (27) from an exhaust boiler, and heat from combustion air (3) via a line to an air inlet (33) of said gas turbine (7), for evaporating LNG (4) to gas which is fed to a gas export module (10) and to a fuel gas skid (8) for supplying said gas turbine (7) with fuel. Thus said combustion air (3, 28) at the air inlet to said gas turbine (7) obtains a lowered temperature and increases an efficiency of said gas turbine (7). Said CO2-rich exhaust gas (77) from said gas turbine (7) is fed into a process unit (17) having an inlet (35a) with a fan (35b) and an outlet for CO2-reduced exhaust (13). Said cooled seawater from said heat exchanger (6) is fed into said process unit (17) via a coaxial feed pipe (67) for seawater and NH4OH arranged in said process unit (17).

Abstract: The use of turbulent contactors to simultaneously absorb selected acid gas components from a gas stream and flash off hydrocarbons entrained in a liquid stream which include a solvent or reagent for the selected gas component. In particular, the method comprises feeding the gas stream and liquid stream into a first contactor where they are contacted co-currently and subjected to turbulent mixing conditions, and passing the multi-phase flow from the first contactor to a second contactor. The multi-phase flow from the second contactor is subsequently separated into a gas phase and a liquid phase.

Abstract: A novel method and system of separating carbon dioxide from flue gas is introduced. Instead of relying on large temperature or pressure changes to remove carbon dioxide from a solvent used to absorb it from flue gas, the ion pump method, as disclosed herein, dramatically increases the concentration of dissolved carbonate ion in solution. This increases the overlying vapor pressure of carbon dioxide gas, permitting carbon dioxide to be removed from the downstream side of the ion pump as a pure gas. The ion pumping may be obtained from reverse osmosis, electrodialysis, thermal desalination methods, or an ion pump system having an oscillating flow in synchronization with an induced electric field.

Abstract: Contemplated plants comprise an acid gas removal unit that receives a compressed gas from an injection gas compressor, wherein acid gas is removed from the compressed gas in the acid gas removal unit at a pressure approximately above pipeline pressure.

Abstract: A plant includes an absorber (103) that operates in a gas phase supercritical region and removes an acid gas from a feed stream (9) at high recovery of the feed stream (10) while producing a high purity acid gas stream (36). Particularly preferred plants include gas purification plants that receive a feed gas with at least 5 mol % carbon dioxide at a pressure of at least 3000 psi.

Abstract: This invention relates to a process for cleaning gas, in particular hydrocarbonaceous gas such as e.g. natural gas, which is contaminated with sulfur in the form of H2S and mercaptans as well as CO2. To remove the undesired sulfur-containing substances in the form of H2S and mercaptan from crude gas, it is proposed in accordance with the invention that the crude gas is introduced into an absorption and regeneration column and washed therein, three gas streams being withdrawn from this absorption and regeneration column, a first exhaust gas stream being introduced into a Claus plant, a second sour gas stream with a low H2S concentration being introduced into another absorption plant, and a third gas stream, the valuable gas with the mercaptans, being cooled and supplied to an adsorption plant, that from this adsorption plant a cleaned valuable gas is withdrawn, and a mercaptan-containing gas stream is subjected to washing, that this concentrated mercaptan-containing gas is supplied to the Claus plant.

Abstract: The arrangements described herein are based upon a theory of selective absorption of hydrogen sulphide over carbon dioxide from gas based on countercurrent contact between gas and tertiary or other amines which exhibit preferential affinity for H2S over CO2 primarily because of differential rates of absorption of the two gases. The process of enhanced selective absorption is accomplished by performing the absorption in two steps. The first operation is to contact lean amine with sour gas which contains both H2S and CO2. The object of the first operation is to produce an overhead gas that meets an arbitrary standard for content of H2S and CO2. The second operation is to enhance the selectivity for H2S by contacting the rich amine leaving the first operation with a second gas which is a highly concentrated acid gas having a higher H2S/CO2 ratio than the first acid gas.

Abstract: Methods are provided for the selective removal of CO2 from a multicomponent gaseous stream to provide a CO2 depleted gaseous stream. In practicing the subject methods, an initial multicomponent gaseous stream is contacted with an aqueous fluid under conditions of selective CO2 clathrate formation to produce a CO2 clathrate slurry and CO2 depleted gaseous stream. A feature of the subject methods is that the CO2 clathrate slurry is then compressed to high pressure to produce a high-pressure CO2 product. Also provided are systems that find use in practicing the subject methods. The subject methods and systems find use in a variety of applications where it is desired to selectively remove CO2 from a multicomponent gaseous stream.

Abstract: Method of making a product gas mixture comprising providing a first gas mixture, contacting the first gas mixture with a lean absorber liquid at a first pressure and absorbing a portion of the first gas mixture in the lean absorber liquid to provide a rich absorber liquid and a non-absorbed residual gas, pressurizing the rich absorber liquid provide a pressurized rich absorber liquid, stripping the pressurized rich absorber liquid with a stripping gas at a second pressure greater than the first pressure to provide a pressurized lean absorber liquid and the product gas mixture, and reducing the pressure of the pressurized lean absorber liquid to provide the lean absorber liquid at the first pressure.

Abstract: A method of removing acid gas components from a gas mixture. Certain embodiments of the method involve bringing the gas mixture into contact with a liquid solvent or reagent for the acid gases in a first turbulent contactor and subjecting the gas mixture and liquid to turbulent mixing conditions. This causes the acid gas to be absorbed by the solvent or reagent. The fluid mixture is passed into a second turbulent contactor and subjected to further turbulent mixing conditions causing further acid gas to be absorbed by the solvent or reagent. Optionally the fluid mixture is separated into a gas phase and liquid phase.

Abstract: A process is described for removing acid gases from a gas stream in which an acid-gas-containing gas stream in which the sum of the partial pressures of the acid gases does not exceed 1,500 mbar is brought into contact with an aqueous absorbent in an absorption step and an absorbent is used which contains methyldiethanolamine and piperazine at a concentration of at least 8% by weight of the absorbent, an acid-gas-depleted gas stream and an acid-gas-loaded absorbent being obtained.

Abstract: A method of separating a gas mixture using a permeation membrane unit, wherein the gas mixture, containing primarily hydrogen and carbon monoxide, is first treated to reduce the level of secondary components to lower than 100 molar ppm.

Abstract: A phase enhanced gas-liquid absorption method is disclosed. By adding an organic mixture or compound into a conventional gas-liquid system, the organic mixture forms a layer between the gas mixture and the liquid carrier. In this modified system, the absorption rate of the gas is significantly increased by the organic mixture, which plays a role of transporting the gas from the gas mixture to the liquid carrier.

Abstract: A description is given of the use of an alkylenediamine of the type R1HN—X—NHR2, where X is an alkylene radical having from 2 to 9 carbons, R1 is a hydrocarbon radical having from 1 to 6 carbons and R2 is a hydrocarbon radical having from 1 to 6 carbons or is hydrogen (H) for removing sour gases from a sour-gas-containing fluid stream, and of a process for deacidifying a fluid stream of this type and a wash liquid or absorption liquid for use in such a process. According to the invention, in at least one absorption step, the fluid stream is brought into intimate contact with a wash liquid, the wash liquid comprising an aqueous amine solution which comprises at least one tertiary aliphatic alkanolamine having from 2 to 12 carbons and an activator of the above type R1HN—X—NHR2. The fluid stream which is substantially freed from sour gases and the sour-gas-loaded wash liquid are then separated from one another.

Abstract: A process for concentrating and recovering methane and carbon dioxide from landfill gas includes absorption of commonly occurring pollutants using a carbon dioxide absorbent which itself may be in situ recoverable constituent. Separated methane is concentrated into a high heating value fuel, and a carbon dioxide product may also be recovered. Process streams may be used to provide fuel for compression and refrigeration and to regenerate carbon dioxide absorbent.

Abstract: The present invention relates to a method for preventing the deposition of contaminants in steam systems. In a method of this type, deposits are prevented in a simple and economic manner by metering an additive into the steam, which additive adheres to the steam-side surface of the steam system and has the effect of repelling moisture and contaminants.

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: In a wet-process gas treatment method of treating an acid gas by using at least two treating columns connected in series, a ratio of the concentration of an acid gas at an outlet to a concentration of the acid gas at an inlet of a first treating column is set higher than a ratio of the concentration of the acid gas at an outlet to the concentration of acid gas at an inlet of at least one of the other treating columns, thereby preventing deposits from forming in the interior of connecting pipes between the columns and in the interiors of the treating columns, to prevent the connecting pipes from being blocked.

Abstract: A process for removing contaminants from a natural gas feed stream including water and sour species is provided, which process comprises the steps of cooling the natural gas feed stream in a first vessel (12) to a first operating temperature at which hydrates are formed and removing from the first vessel (12) a stream of dehydrated gas (34); and cooling the dehydrated gas in a second vessel (14) to a second operating temperature at which solids of the sour species are formed or at which the sour species dissolve in a liquid and removing from the second vessel (14) a stream of dehydrated sweetened gas (62).

Abstract: Methods are provided for the selective removal of CO2 from a multicomponent gaseous stream to provide a CO2 depleted gaseous stream. In practicing the subject methods, an initial multicomponent gaseous stream that includes a gaseous CO2 hydrate promoter is contacted with an aqueous fluid, e.g., CO2 nucleated water, in a hydrate formation reactor under conditions of selective CO2 clathrate formation to produce a CO2 clathrate slurry and CO2 depleted gaseous stream. Also provided are systems that find use in practicing the subject methods. The subject methods and systems find use in a variety of applications where it is desired to selectively remove CO2 from a multicomponent gaseous stream.

Abstract: A pretreatment system for natural gas liquefaction employing heat integration for more efficient and effective natural gas temperature control. The pretreatment system expands the natural gas prior to acid gas removal. After acid gas removal, the natural gas is cooled by indirect heat exchange with the expanded natural gas located upstream of the acid gas removal system.

Abstract: A process is described for removing acid gases from a gas stream in which an acid-gas-containing gas stream in which the sum of the partial pressures of the acid gases does not exceed 1 500 mbar is brought into contact with an aqueous absorbent in an absorption step and an absorbent is used which contains methyldiethanolamine and piperazine at a concentration of at least 8% by weight of the absorbent, an acid-gas-depleted gas stream and an acid-gas-loaded absorbent being obtained.

Abstract: An exhaust heat utilization method for a carbon dioxide recovery process comprises heating returning hot water by at least one heat exchange selected from heat exchange with the regenerated absorbing liquid after heat exchange, heat exchange with carbon dioxide exhausted from the regeneration tower, and heat exchange with saturated water after heating the bottom of the regeneration tower, thereby obtaining hot water.

Abstract: Methods are provided for the selective removal of CO2 from a multicomponent gaseous stream to provide a CO2 depleted gaseous stream. In practicing the subject methods, an initial multicomponent gaseous stream that includes a gaseous CO2 hydrate promoter is contacted with an aqueous fluid, e.g., CO2 nucleated water, in a hydrate formation reactor under conditions of selective CO2 clathrate formation to produce a CO2 clathrate slurry and CO2 depleted gaseous stream. In certain embodiments, a feature of the subject invention is that additional gaseous CO2 hydrate promoter is introduced into the process stream at some point prior the output of the hydrate reactor. In certain embodiments, a feature of the subject invention is that the hydrate formation reactor is a tubular finned reactor. Also provided are systems that find use in practicing the subject methods. The subject methods and systems find use in a variety of applications where it is desired to selectively remove CO2 from a multicomponent gaseous stream.

Abstract: A carbon dioxide recovery apparatus and process for supercritical extraction includes providing a process stream from a supercritical extraction procedure in which the process stream includes pressurized carbon dioxide, extraction process waste and optionally at least one co-solvent; reducing the pressure of the process stream below critical pressure; venting low pressure carbon dioxide vapor to exhaust; cooling the process stream to form a two phase mixture; separating the two phase mixture into a process liquid, containing co-solvent if present, and a process vapor phase stream; collecting the process liquid; filtering the process vapor phase stream to remove particulates and optionally residual co-solvent; passing the filtered process vapor stream through an adsorber to remove trace impurities to form a purified carbon dioxide vapor stream; and, drying the purified carbon dioxide vapor stream to remove residual water vapor.

Abstract: A process for pretreating a very acid natural gas containing a substantial amount of hydrogen sulfide (H2S), possibly combined with carbon dioxide (CO2), includes at least a stage wherein the initial natural gas is contacted in a distillation column with a liquid condensate itself resulting from cooling of the gaseous fraction obtained during the contacting stage. This solution allows to eventually recover at a lower cost a gas enriched in methane, depleted in hydrogen sulfide and freed from substantially all of the water it contains, and a liquid phase containing most of the hydrogen sulfide, substantially all of the water and depleted in hydrocarbon. Control of the thermodynamic conditions during the stages that characterize the process, according to the water content of the gas during treatment, allows progressive exhaustion of the water contained in the gas while preventing hydrates formation.