Abstract: Methods of sequestering carbon dioxide (CO2) are provided. Aspects of the methods include precipitating a storage stable carbon dioxide sequestering product from an alkaline-earth-metal-containing water and then disposing of the product, e.g., by placing the product in a disposal location or using the product as a component of a manufactured composition. Also provided are systems for practicing methods of the invention.

Abstract: Methods of sequestering carbon dioxide (CO2) are provided. Aspects of the methods include precipitating a storage stable carbon dioxide sequestering product from an alkaline-earth-metal-containing water and then disposing of the product, e.g., by placing the product in a disposal location or using the product as a component of a manufactured composition. Also provided are systems for practicing methods of the invention.

Abstract: A fluidized bed reactor device for sequestering flue gas CO2 from a flue gas source is provided. The fluidized bed reactor device comprises an operating portion having a first end and a second end. A flue gas inlet is formed at the first end of the operating portion with the flue gas inlet receiving flue gas from the flue gas source. A flue gas outlet formed at the second end of the operating portion. A distributor plate is mounted within the operating portion adjacent the first end of the operating portion. A volume of fly ash is encased within the operating portion between the second end and the distributor plate with the flue gas traveling through the distributor plate and the fly ash creating reacted flue gas wherein the reacted flue gas exits the operating portion through the flue gas outlet.

Abstract: Two methods are provide for the separation of carbon dioxide from the flue gases. The first method utilizes a phase-separating moiety dissolved in an aqueous solution of a basic moiety to capture carbon dioxide. The second method utilizes a phase-separating moiety as a suspended solid in an aqueous solution of a basic moiety to capture carbon dioxide. The first method takes advantage of the surface-independent nature of the CO2 absorption reactions in a homogeneous aqueous system. The second method also provides permanent sequestration of the carbon dioxide. Both methods incorporate the kinetic rate enhancements of amine-based scrubbing while eliminating the need to heat the entire amine solution (80% water) in order to regenerate and release CO2. Both methods also take advantage of the low-regeneration temperatures of CO2-bearing mineral systems such as Na2CO3/NaHCO3 and K2CO3/KHCO3.

Abstract: A method of recovering carbon dioxide from a stream of flue gases, includes: contacting the stream at a gas pressure above atmospheric pressure with an aqueous solvent system, containing ammonium, carbonate and bicarbonate ions, at a temperature above 10° C. to effect absorption of CO2 from the stream, and separating the solvent containing the absorbed CO2 (as carbonate, bicarbonate and CO2(aq)) from the stream of CO2-leaner flue gases to form a CO2 and/or bicarbonate-rich solvent stream. In a second aspect, the CO2-leaner flue gases are cooled by contact with water that dissolves ammonia therefrom, and recycling said dissolved ammonia back to said solvent system. Apparatus is also disclosed.

Abstract: A device for purifying smoke gases comprising a cylindrical container with a gas inlet at its bottom region and a gas exit for purified gas in its top region, as well as an inlet for washing liquid and an exit for spent washing liquid, wherein the container internally does not include any current baffles so that the gas and liquid can rotate freely, and wherein the container internally has a stirring device of perforated plates, e.g. netting discs, for optimal mixing of gas and fluid. It is also disclosed a process for purifying such smoke gases, wherein such a purification device is used.

Abstract: The invention provides a process for sequestration of carbon dioxide by mineral carbonation comprising the following steps: (a) converting a magnesium or calcium sheet silicate hydroxide into a magnesium or calcium ortho- or chain silicate by bringing the silicate hydroxide in direct or indirect heat-exchange contact with hot flue gas to obtain the silicate, silica, water and cooled flue gas; (b) contacting the silicate obtained in step (a) with carbon dioxide to convert the silicate into magnesium or calcium carbonate and silica.

Abstract: A system and method for removing sulfur-containing contaminants from indoor air includes a panel system having a first layer and a second layer. The first layer can include a base media onto which sodium bicarbonate is attached. The second layer can include a base media onto which activated carbon is attached. Indoor air including sulfur-containing contaminants can contact and pass through the first layer. Sulfuric acid can react with the sodium bicarbonate to produce sodium sulfate, which can, in turn, act as a drying agent for organic sulfur-containing contaminants in the indoor air, such as carbon disulfide and carbonyl sulfide. As a result of such drying, the second layer can more effectively trap and/or bind (adsorb) the organic sulfur-containing contaminants so that these contaminants are removed from the contaminated air. The treated air can be returned to an indoor space of the structure.

Abstract: A method for separating carbon dioxide from a flue gas using a membrane (membrane module) is characterized in that the flue gas is at temperatures above the condensation point of the water vapor before entering the membrane separation stage. In this way, condensation of any potentially entrained water vapor out of the flue gas is avoided, so as to consistently prevent clogging of the membrane pores. The high temperatures can be achieved in different ways. The temperature of the flue gas can easily be increased to the necessary temperatures by way of an upstream heat exchanger or a burner. A compressor, which is connected upstream of the membrane module and also advantageously increases the CO2 partial pressure, brings about the necessary temperature increase at the same time. As a further alternative for the invention, the CO2 separation is performed even before desulfurizing the flue gas.

Abstract: A method of treating fly ash to modify the set time and the induction profile for a slurry comprising cement and the fly ash. The method comprising mixing fly ash with an aqueous solution comprising the calcium carbonate, thereby modifying the set time and the induction profile of the slurry comprising cement and the fly ash. A method of treating fly ash to modify the induction profile of a slurry comprising cement and the fly ash. The method comprising contacting fly ash with a wet gas stream comprising water vapor and carbon dioxide in an amount sufficient to react with the fly ash so as to modify the induction profile of the slurry comprising cement and the fly ash. Cement compositions comprising water, hydraulic cement, and carbonated fly, and associated methods of use.

Abstract: The gaseous effluent to be treated is contacted in C1 with an absorbent solution selected for its property of forming two separable phases when it has absorbed an amount of acid compounds and when it is heated. The absorbent solution laden with acid compounds is then heated in E1 and E3 so as to separate two fractions in BS1: a first absorbent solution fraction depleted in acid compounds and a second absorbent solution fraction enriched in acid compounds. The second fraction is regenerated in C2 so as to release part of the acid compounds, and the first absorbent solution fraction and the regenerated absorbent solution are recycled as absorbent solution. According to the invention, an absorbent solution portion circulating in C1 is cooled in E2 in order to prevent demixing of the solution in column C1.

Abstract: A process for sequestering carbon dioxide, which includes reacting a silicate based material with an acid to form a suspension, and combining the suspension with carbon dioxide to create active carbonation of the silicate-based material, and thereafter producing a metal salt, silica and regenerating the acid in the liquid phase of the suspension.

Abstract: A process is described for sequestering carbon dioxide. In the process, a carbonate, oxide or hydroxide of a divalent cation is reacted with the carbon dioxide and water and/or with a species resulting from the dissolution of the carbon dioxide in water, to form a hydrogen carbonate of the divalent cation. The carbonate, oxide or hydroxide of the divalent cation has a low solubility in water. The divalent cation of the hydrogen carbonate of the divalent cation thus formed is exchanged for a monovalent cation using an ion exchange medium, to produce a solution of a hydrogen carbonate of the monovalent cation.

Abstract: There is provided a process for the capture and sequestration of carbon dioxide that would otherwise enter the atmosphere and contribute to global warming and other problems. CO2 capture is accomplished by reacting carbon dioxide in flue gas with an alkali metal carbonate, or a metal oxide, particularly containing an alkaline earth metal or iron, to form a carbonate salt. A preferred carbonate for CO2 capture is a dilute aqueous solution of additive-free (Na2CO3). Other carbonates include (K2CO3) or other metal ion that can produce both a carbonate and a bicarbonate salt. Examples of suitable metal oxides include several alkaline earths including CaO and MgO. The captured CO2 is preferably sequestered using any available mineral or industrial waste that contains calcium magnesium or iron in non-carbonate forms, or iron in the Fe+2 oxidation state.

Abstract: The invention relates to a fluid separating device with a lower section with a fluid feeding device and a liquid discharging device, an upper section with a fluid feeding device and a gas discharging device, a contact device which is constructed in such a manner that gas, which rises from the lower section into the upper section, comes into contact with liquid which sinks from the upper section into the lower section. Thereby, the rising gases can be depleted of components which are soluble in said liquid. Furthermore, a measuring device for determining the quantity of liquid and/or the alterations thereof is provided.

Abstract: The invention teaches a practical method of recovering CO2 from a mixture of gases, and sequestering the captured CO2 from the atmosphere for geologic time as calcium carbonate and provides a CO2 scrubber for carbon capture and sequestration. CO2 from the production of calcium oxide is geologically sequestered. A calcium hydroxide solution is produced from the environmentally responsibly-produced calcium oxide. The CO2 scrubber incorporates an aqueous froth to maximize liquid-to-gas surface area and time-of-contact between gaseous CO2 and the calcium hydroxide solution.

Abstract: An exhaust gas treatment system is provided that can sufficiently remove pollutants such as SO3 contained in combustion exhaust gas at low cost. In the exhaust gas treatment system for removing pollutants such as SO3 contained in combustion exhaust gas, there is provided dissolved salt aqueous solution sprays 35A, 35B, and 35C, that spray an Na2SO4 aqueous solution obtained from desulfurization effluent of a wet desulfurization system, into a flue though which the combustion exhaust gas flows.

Abstract: A method of earning carbon credits includes sequestering carbon dioxide by cultivating aquatic organisms that have carbon-containing shells and obtaining carbon credits based on the sequestered carbon dioxide.

Abstract: The activity and durability of a zeolite lean-bum NOx catalyst can be increased by loading metal cations on the outer surface of the zeolite. However, the metal loadings can also oxidize sulfur dioxide to cause sulfate formation in the exhaust. The present invention is a method of suppressing sulfate formation in an exhaust purification system including a NOx catalyst. The NOx catalyst includes a zeolite loaded with at least one metal. The metal is selected from among an alkali metal, an alkaline earth metal, a lanthanide metal, a noble metal, and a transition metal. In order to suppress sulfate formation, at least a portion of the loaded metal is complexed with at least one of sulfate, phosphate, and carbonate.

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 device for absorbing carbon dioxide, which is equipped along an automobile exhaust pipe and a factory chimney. The present invention also relates to a method for absorbing carbon dioxide. According to the present invention, there is provided a device for absorbing carbon dioxide, comprising a housing 4 of a material having air permeability; a cement composition for absorbing carbon dioxide, enclosed inside the housing 4; and a pipe 5 across the housing, the pipe having an inlet 2 and an outlet 3. According to the present invention, when a gas is introduced from the inlet 2, carbon dioxide in the gas is absorbed by the carbon dioxide absorbing materials such as a cement composition enclosed in the housing 4. The gas is discharged from the outlet 3.

Abstract: The present invention relates to a pozzolanic admixture containing ammonia-laden fly ash, method for making the pozzolanic admixture and method for controlling ammonia gas (NH3) emission from cementitious slurries using the pozzolanic admixture. The associated hypochlorite and ammonia reaction produces monochloramine and chloride salts at relatively low concentration levels harmless to concrete and concrete applications. The resulting monochloramine and chloride salt products are stable and do not dissipate into the air, thereby, eliminating odorous emission that is produced from cementitious slurry containing untreated ammonia laden fly ash.

Abstract: Process for the removal of carbon dioxide (CO2) and minor sulfur compounds—mainly hydrogen sulfide (H2S)—from a sour gas mixture, such as natural gas, iron ore reduction gas, etc. The process uses a continuous absorption process with an alkaline aqueous liquid mixture containing 15-40% by weight of equivalent K2CO3 and is conducted at a temperature of about 150 degrees F. to 300 degrees F. The H2S is removed from the sour gas as elemental sulfur. A high concentration (at least 10 to 1 molar ratio) of penta-valent vanadium (V+5) to H2S is maintained at a high temperature (150 to 300 degrees F.) to help minimize thiosulfate formation, raise the absorption temperature, and increase the speed of conversion of H2S to elemental sulfur. CO2 is stripped from the aqueous alkaline solution and vented directly into the atmosphere since the sulfur that usually contaminates the CO2 was removed earlier in the process as elemental sulfur.

Abstract: The present invention is a process to recover a high purity, high pressure hydrogen gas stream from synthesis gas. The synthesis gas is contacted with a membrane that separates the synthesis gas into a hydrogen-enriched permeate and a hydrogen-depleted non-permeate. The permeate is conveyed to a carbon dioxide absorber. The carbon dioxide absorber removes carbon dioxide using a solvent. The carbon dioxide-rich solvent from the absorber is heated and sent to a gas-liquid contactor, where the solvent is regenerated by nitrogen stripping. A small recycle stream of a regenerating gas, i.e., hydrogen, is subsequently contacted with the solvent, stripping entrained and dissolved nitrogen from the solvent. This stripping gas, the regenerating gas, or preferably both, are then mixed with the non-permeate for combustion in a combustion turbine.

Abstract: The present invention provides a method for inhibiting the evolution of H2S from sulfhydryl compounds in molten sulfur by using scavenging agents such as anhydrides and polymers thereof, conjugated ketones, carbonates, epoxides, monoesters and diesters of unsaturated dicarboxylic acids and polymers of these esters, and the like and mixtures thereof. In one embodiment, it is preferred that the scavenging agent is in liquid form at contact temperature with the molten sulfur. In another embodiment, the scavenging agent may be atomized into the vapor space over the molten sulfur to contact the sulfur with the agent.

Abstract: A process to remove carbon dioxide from a gas stream using a cross-flow, or a moving-bed reactor. In the reactor the gas contacts an active material that is an alkali-metal compound, such as an alkali-metal carbonate, alkali-metal oxide, or alkali-metal hydroxide; or in the alternative, an alkaline-earth metal compound, such as an alkaline-earth metal carbonate, alkaline-earth metal oxide, or alkaline-earth metal hydroxide. The active material can be used by itself or supported on a substrate of carbon, alumina, silica, titania or aluminosilicate. When the active material is an alkali-metal compound, the carbon-dioxide reacts with the metal compound to generate bicarbonate. When the active material is an alkaline-earth metal, the carbon dioxide reacts with the metal compound to generate carbonate.

Abstract: A process and system for reducing the concentration of odorous contaminants, primarily hydrogen sulfide, in the vapor spaces of sewage handling and treatment systems, primarily the vapor spaces of sewage trunk lines, by injecting a fine spray, mist or fog of a dilute solution of hydrogen peroxide and a base selected from a group consisting of sodium hydroxide, potassium hydroxide, ammonium hydroxide and sodium carbonate to mix intimately with the vapor flow. The peroxide and base solutions may be pre-mixed and diluted with water and injected through atomizing nozzles utilizing compressed air as an atomizing fluid. The system may also provide for separate storage of the peroxide and base solutions, mixing of the peroxide and base solutions with dilution water with in-line mixing devices and direct injection with or without compressed air atomization into the vapor space.

Abstract: An aqueous stream such as pulp mill condensate containing one or more sulfur compounds is treated by (a) reacting an aqueous feed stream containing TRS contaminant selected from the group consisting of hydrogen sulfide, methyl mercaptan, dimethyl sulfide, dimethyl disulfide, and mixtures thereof, with ozone to produce a first liquid product stream and a first gaseous product stream, wherein the total amount of said one or more contaminants in said first liquid product stream is less than 1% of the amount thereof in said feed stream, and wherein said first gaseous product stream contains ozone and one or more of said contaminants; and (b) treating said first gaseous product stream with an alkaline aqueous stream to remove essentially all of said one or more contaminants from said first gaseous product stream. Preferably, a second gaseous stream produced in step (b) and containing ozone is reacted with an aqueous stream containing one or more of said contaminants, to consume all the ozone in said stream.

Abstract: The invention relates to the absorption of carbon dioxide from a process gas using a solution of potassium carbonate, potassium bicarbonate, diethanolamine and potassium vanadate, followed by desorption of the carbon dioxide from the solution and recycling the regenerated solution. Organic acid salts of potassium build up in the aqueous solution is diluted with aqueous diluent, and then passed over a semi-permeable membrane such as a nanofiltration membrane, and ultrafiltration membrane or a reverse-osmosis membrane using a pressure drop to remove the organic acid salts of potassium from the side stream.

Abstract: A process and an apparatus in black-liquor evaporation for the selective removal, by liquid absorption, of hydrogen sulphide from the generated gas (3) containing hydrogen sulphide as well as carbon dioxide, an disclosed. In the process, the gas is counter-currently brought into multistage contact, preferably comprising three stages (6, 7, 8), with circulating carbonate-containing alkaline solutions, preferably sodium carbonate solutions (25), the pH of which is adjusted during the absorption to about 9-12 by the addition of a hydroxide, preferably a sodium hydroxide solution (26, 27, 28). It is preferred that the gas flow is turbulent and the liquid flow is laminar when contacted with one another. The apparatus comprises a container (1) having a gas inlet (2), a gas outlet (4), and a packing (9) arranged in several successive stages (6, 7, 8).

Abstract: In a process and corresponding device for scrubbing acidic gases out of flue gases using adsorbent-containing suspensions, the flue gases are conveyed into a scrubber with narrowing channels and accelerated in a first stage in a direction opposite to the flow of suspension droplets and in a second stage in the same direction as the flow of liquid droplets, the suspension having already been broken down into droplets before or at the beginning of the acceleration section. Reflux of the suspension into the acceleration section is prevented by the shape of the channels. Flue gas and suspension droplets react and in the connecting first mist precipitator, the droplets are turned around 180° in the direction of gravitational forces.

Abstract: Degassing is accomplished by driving a gas-containing solution to a subatmospheric pressure approximately equal to the solution vapor pressure, and maintaining the subatmospheric pressure notwithstanding evolution of gas from the solution. This may be accomplished using a vacuum tower arrangment whereby a column of the gas-containing liquid is drawn to the maximum physically attainable height. So long as the vacuum is coupled to the liquid column above this height (generally on the order of 34 feet, depending on the ambient temperature and the composition of the liquid), the liquid will not be drawn into the vacuum, which creates a non-equilibrium region of extremely low pressure above the liquid that liberates dissolved gases. Moreover, liquid introduced into the low-pressure region above the column will fall onto the column without entering the vacuum system.

Abstract: A process for purifying a fluid stream contaminated with carbon dioxide is provided which comprises contacting, under conditions sufficient to substantially remove the contaminated carbon dioxide from the fluid stream which contains at least one C.sub.2 -C.sub.5 olefin such as ethylene or propylene, with a composition containing an oxygen-containing metal compound such as, for example, an alkaline earth metal hydroxide. The contacting is carried out in the presence of water.

Abstract: This invention relates to a process for removing highly concentrated CO.sub.2 from high-pressure natural gas and recovering it in a high-pressure state.This process comprises the absorption step of bringing high-pressure natural gas having a CO.sub.2 partial pressure of 2 kg/cm.sup.2 or greater and a pressure of 30 kg/cm.sup.2 or greater into gas-liquid contact with a regenerated CO.sub.2 -lean absorbing fluid comprising a CO.sub.2 absorbing fluid of which the difference in saturated CO.sub.2 absorption level between 40.degree. C. and 120.degree. C. is not less than 30 Nm.sup.3 per ton of solvent at a CO.sub.2 partial pressure of 2 kg/cm.sup.2, whereby highly concentrated CO.sub.2 present in the high-pressure natural gas is absorbed into the CO.sub.2 -lean absorbing fluid to produce refined natural gas having a reduced CO.sub.2 content and a CO.sub.2 -rich absorbing fluid; and the regeneration step of heating the CO.sub.2 -rich absorbing fluid without depressurizing it, whereby high-pressure CO.sub.

Abstract: Absorbents, suitable for absorbing sulphur compounds such as hydrogen sulphide from gases and liquids, in the form of shaped units having an average size within the range 1-10 mm and containing at least 75% by weight of an absorbent material comprising copper carbonate, basic copper carbonate, and/or copper hydroxide. The units preferably have a bulk density of at least 0.9 kg/l, especially at least 1.2 kg/l. The units are preferably agglomerates containing a small amount of a binder such as a cement and may also contain a proportion of alumina to catalyse hydrolysis of carbon-containing sulphur compounds such as carbonyl sulphide or carbon disulphide.

Abstract: A technique for preparing a flat sheet, high capacity CO.sub.2 sorbent and sorbent assembly is disclosed. The sorbent, which is in the form of a sheet, can be a metal oxide/alkali metal carbonate regenerable sorbent, while the sorbent assembly is comprised of the sheet sorbents located between constraining means and gas flow passages.

Abstract: A process and system for removal of hydrogen sulfide from a hydrogen sulfide-containing gaseous stream comprising contacting the hydrogen sulfide-containing gaseous stream with a nonaqueous phase sorbent under conditions suitable for forming a hydrogen sulfide-laden sorbent and a clean gaseous stream. The hydrogen sulfide-laden sorbent is mixed with an aqueous phase redox coupled, regenerating the nonaqueous phase sorbent, reducing the aqueous phase redox couple, and forming sulfur. The sulfur is separated from the mixture. The reduced aqueous phase redox couple is extracted from the mixture and regenerated with an oxidizing agent or electrochemical cell.

Abstract: A gas treating composition prepared by reacting 2-amino-2-methyl-1-propanol with KOH, diluting with water and adding K.sub.2 CO.sub.3 and a vanadium corrosion inhibitor.

Abstract: Improved processes for treating gas streams containing hydrogen sulfide and carbon dioxide, particularly natural gas streams. The processes rely on the availability of a membrane that maintains high hydrogen sulfide/methane selectivity and adequate hydrogen sulfide/carbon dioxide selectivity when measured with multicomponent gas mixtures at high pressure. The processes have three steps: an acid gas removal step, to remove both hydrogen sulfide and carbon dioxide from the primary gas stream; a membrane fractionation step, to separate hydrogen sulfide from carbon dioxide and create a highly hydrogen-sulfide-concentrated fraction; and a sulfur-fixing step.

Abstract: A method of separating sulphur compounds out of a gas containing carbon dioxide and hydrogen sulphide, in a gas washing system, said gas being obtained by gasification of spent cellulose liquor. According to the invention the gas washing system has a gas-liquid contact zone (5) operating at a pressure exceeding atmospheric pressure as well as a regeneration zone (8) operating at a pressure substantially less than the pressure in the gas-liquid contact zone (5). The carbon dioxide partial pressure in the gas prior to entering the gas-liquid contact zone exceeds 0.2 atm. Furthermore the gas comes into contact with an alkaline absorption liquid in the gas-liquid contact zone, and alkaline liquid containing alkali hydrogen sulphide is withdrawn from the gas-liquid contact zone and transferred to the regeneration zone, in which zone hydrogen sulphide is expelled from said liquid containing alkali hydrogen sulphide and withdrawn in the form of a gas.

Abstract: Improved processes for treating gas streams containing hydrogen sulfide and carbon dioxide, particularly gas streams from fossil fuel gasification processes. The processes rely on the availability of a membrane that maintains high hydrogen sulfide/methane selectivity and adequate hydrogen sulfide/carbon dioxide selectivity when measured with multicomponent gas mixtures at high pressure. The processes have three steps: an acid gas removal step, to remove both hydrogen sulfide and carbon dioxide from the primary gas stream; a membrane fractionation step, to separate hydrogen sulfide from carbon dioxide and create a highly hydrogen-sulfide-concentrated fraction; and a sulfur-fixing step.

Abstract: Carbon dioxide sorption using a metal oxide-alkali metal carbonate sorbent typically requires a relative humidity of greater than 25% in order to obtain reaction rate constants of about 2.0 to 3.0 sec..sup.1 (see Equation 6). The incorporation of alkali halide salt into the metal oxide-alkali metal carbonate sorbent maintains rate constants of about 2.0 to about 4.0 sec..sup.1 at relative humidities below 25%. Therefore, the hygroscopic alkali halide salt attracts water, thereby providing the necessary hydroxide ions for enhanced absorption at low relative humidities.

Abstract: A technique for preparing a flat sheet, high capacity CO.sub.2 sorbent and sorbent assembly is disclosed. The sorbent, which is in the form of a sheet, can be a metal oxide/alkali metal carbonate regenerable sorbent, while the sorbent assembly is comprised of the sheet sorbents located between constraining means and gas flow passages.

Abstract: A membrane for the separation of carbon dioxide is disclosed which includes a hydrogel film of a cross-linked, vinyl alcohol/acrylic acid salt copolymer impregnated with an aqueous carrier solution containing a carbon dioxide carrier dissolved therein. A composition containing a solvent, an alkali metal carbonate or bicarbonates, and a polydentate ligand capable of forming a complex with an alkali metal ion is suitably used as the carrier solution. This composition may also be used for the preparation of a liquid film of a carbon dioxide separation membrane.

Abstract: A technique for preparing an unsupported, high capacity CO.sub.2 sorbent. The sorbent is comprised of silver carbonate, alkali metal silicate and alkaline earth metal salt binders for structural integrity, and alkali metal carbonate for CO.sub.2 sorption promotion. The sorbent disclosed in this invention has a high silver oxide density, consumes minimum volume, exhibits high CO.sub.2 absorption rates, and resists dusting and degradation for at least 50 absorption/desorption cycles.

Abstract: A process for the removal of sulphur compounds from a gaseous effluent, comprising the steps of: a) contacting the gaseous effluent with an aqueous solution wherein sulphur compounds are dissolved; b) adjusting the concentration of buffering compounds such as carbonate and/or bicarbonate and/or phosphate in the aqueous solution to a value between 20 and 2000 meq/l; c) subjecting the aqueous solution containing sulphide to sulphide-oxidizing bacteria in the presence of oxygen in a reactor wherein sulphide is oxidized to elemental sulphur; d) separating elemental sulphur from the aqueous solution; and e) recycling the aqueous solution to step a). This process is suitable for removing H.sub.2 S from biogas, ventilation air etc. It can be used for removing SO.sub.2 from combustion gases by introducing the additional step, after step a) and before step c), of subjecting the aqueous solution containing the sulphur compounds to a reduction of the sulphur compounds to sulphide. H.sub.2 S and SO.sub.

Abstract: Carbon dioxide sorption using a metal oxide-alkali metal carbonate sorbent typically requires a relative humidity of greater than 25% in order to obtain reaction rate constants of about 2.0 to 3.0 sec..sup.-1 (see Equation 6). The incorporation of alkali halide salt into the metal oxide-alkali metal carbonate sorbent maintains rate constants of about 2.0 to about 4.0 sec..sup.-1 at relative humidities below 25%. Therefore, the hygroscopic alkali halide salt attracts water, thereby providing the necessary hydroxide ions for enhanced absorption at low relative humidities.

Abstract: A process and apparatus is disclosed for reclaiming of heat of reaction energy from an alkaline scrubbing solution used in acid gas removal processes and apparatus therefor. The heat recovered is used to produce steam which may then be employed to assist in steam stripping the rich scrubbing solution to effect regeneration thereof. The rich scrubbing solution containing heat of reaction thermal energy is passed through a rich-reflux reboiler to recover a part of the energy to produce at least a part of the stripping steam, and then through a rich-lean reboiler under a reduced pressure to produce additional quantities of stripping steam. A reduction in steam requirements for regeneration of the rich alkaline scrubbing agent of at least 10% is thereby realized.

Abstract: Formation of toxic polychlorinated dibenzo-p-dioxins and other chlorinated compounds by catalytic reactions on flyash produced in the process of solid waste incineration is a universal phenomenon. By providing inhibitors which adsorb on the flyash prior to catalytic reaction initiation to suppress catalytic reactions on the flyash, in the postcombustion zone of the incinerator, or by spraying the inhibitors on the solid wastes prior to incineration, has resulted in a decrease in dioxins and other chlorinated compounds on the flyash and in the stack emissions. Introduction of inorganic and organic basic compounds on solid waste or between combustion and precipitation regions of the incinerator also decreases acid gases in the stack emissions.

Abstract: Processes are disclosed for purifying hydrocarbon feedstreams, e.g, natural gas, to remove carbonyl sulfide and other acid gases such as carbon dioxide and hydrogen sulfide. The processes employ a conversion step to convert carbonyl sulfide to hydrogen sulfide and carbon dioxide followed by an absorption step to remove the carbon dioxide and hydrogen sulfide from the feedstream. Carbonyl sulfide is converted to carbon dioxide and hydrogen sulfide in the presence of an aqueous alkaline solution which preferably has the same composition as the absorption solution used in the absorption step.