Abstract: A process for removing CO2 from a combustion gas which comprises bringing a combustion gas containing oxygen and CO2 and a CO2 absorbent solution into contact at the atmospheric pressure, thereby allowing the CO2 absorbent solution to absorb CO2 from the combustion gas, and, in the ensuing step, heating the absorbent solution that has absorbed CO2 to liberate CO2 and regenerate the CO2 absorbent solution, and circulating the regenerated solution for reuse. An aqueous solution of a hindered amine selected from the group consisting of 2-amino-2-methyl-1-propanol (AMP), 2-(ethylamino)-ethanol (EAE), 2-(methylamino)-ethanol (MAE), and 2-(diethylamino)-ethanol (DEAE) is used as the CO2 absorbent solution, and carbon steel is used in building the members of the equipment that contact the aqueous hindered amine solution. The absorbent solution contains cupric carbonate which is a corrosion inhibitor.

Abstract: There are disclosed a method for removing CO2 from a combustion exhaust gas which comprises the step of bringing the combustion exhaust gas under atmospheric pressure into contact with an aqueous solution of a hindered amine selected from the group consisting of 2-amino-2-methyl-1-propanol, 2-methylaminoethanol, 2-ethylamino-ethanol and 2-piperidineethanol; and another method for removing carbon dioxide from a combustion exhaust gas which comprises the step of bringing the combustion exhaust gas under atmospheric pressure into contact with a mixed aqueous solution of 100 parts by weight of an amine compound (X) selected from the group consisting of 2-amino-2-methyl-1, 3-propanediol, 2-amino-2-methyl-1-propanol, 2-amino-2-ethyl-1, 3-propanediol, t-butyldiethanolamine and 2-amino-2-hydroxymethyl-1,3-propanediol; and 1-25 parts by weight of an amine compound (Y) selected from the group consisting of piperazine, piperidine, morpholine, glycine, 2-methylamino-ethanol, 2-piperidineethanol and 2-ethylaminoethanol.

Abstract: A method for the regeneration of an acid gas absorbing fluid which comprises bringing a gaseous mixture containing an acid gas such as, for example, gasified coal gas, synthesis gas, coke oven gas, petroleum gas, natural gas, and the like, into contact with an absorbing fluid containing methyldiethanolamine and a (lower alkyl)piperizine such as, for example, 2-methylpiperazine or 2,5-dimethylpiperazine, so as to absorb the acid gas into the absorbing fluid, and regenerating the absorbing fluid by releasing the acid gas from the absorbing fluid by releasing the acid gas from the absorbing fluid in a regeneration tower having a temperature of not less than 40° C., preferably from 40° C. to 80° C.

Abstract: A process is provided for removing carbon dioxide out of combustion exhaust gas by scrubbing the exhaust gas with an aqueous solution of monoethanolamine in a scrubber, and regenerating the carbon dioxide-loaded aqueous solution of monoethanolamine in a regenerator. The process is provided with means for replenishing the aqueous solution of monoethanolamine with a stock, aqueous solution containing from about 70% to about 75% by weight of monoethanolamine. By providing a stock, aqueous solution containing from about 70% to about 75% by weight of monoethanolamine, which is injected into the carbon dioxide-loaded aqueous solution of monoethanolamine being transferred from the scrubber to the regenerator, the entire carbon dioxide recovery system is free from flammables, rendering fire-fighting precautions unnecessary.

Abstract: The present invention provides a process for recovering a basic amine compound which comprises the steps of (a) supplying a CO.sub.2 -containing gas to a carbon dioxide absorption unit in which an absorbing solution, which contains a basic amine compound, absorbs carbon dioxide; (b) bringing the gas, from which carbon dioxide has been removed, into vapor-liquid contact with a washing water at a temperature from 20 to 60.degree. C. in an amine recovering unit of a carbon dioxide removal tower, recovering part of the basic amine compound accompanying the gas into the water phase and discharging the gas as an exhaust gas of the carbon dioxide removal tower; and (c) collecting the basic amine compound which remains in the exhaust gas of the carbon dioxide removal tower by passing the exhaust gas pass through a demister at a temperature from 20 to 60.degree. C. The basic amine compound can be recovered efficiently from the gas of the carbon dioxide removal tower by using the above process.

Abstract: This invention provides a method for the removal of carbon dioxide present in gases which comprises bringing a CO.sub.2 -containing gas into contact with an aqueous solution containing at least one amine compound of the general formula ##STR1## wherein R.sup.1 to R.sup.8 may be the same or different and each represent a hydrogen atom or an alkyl group of 1 to 4 carbon atoms, and m is 0 or 1. The method of the present invention makes it possible to remove carbon dioxide efficiently. In particular, since carbon dioxide can be easily desorbed by heating the aqueous solution having absorbed carbon dioxide, the thermal energy required for regeneration of the aqueous solution can be reduced.

Abstract: There are disclosed a method for removing CO.sub.2 from a combustion exhaust gas which comprises the step of bringing the combustion exhaust gas under atmospheric pressure into contact with an aqueous solution of a hindered amine selected from the group consisting of 2-amino-2-methyl-1-propanol, 2-methylaminoethanol, 2-ethylaminoethanol and 2-piperidineethanol; and another method for removing carbon dioxide from a combustion exhaust gas which comprises the step of bringing the combustion exhaust gas under atmospheric pressure into contact with a mixed aqueous solution of 100 parts by weight of an amine compound (X) selected from the group consisting of 2-amino-2-methyl-1,3-propanediol, 2-amino-2-methyl-1-propanol, 2-amino-2-ethyl-1,3-propanediol, t-butyldiethanolamine and 2-amino-2-hydroxymethyl-1,3-propanediol; and 1-25 parts by weight of an amine compound (Y) selected from the group consisting of piperazine, piperidine, morpholine, glycine, 2-methylaminoethanol, 2-piperidineethanol and 2-ethylaminoethanol.

Abstract: This invention provides a method for the removal of carbon dioxide present in gases which comprises bringing a CO.sub.2 -containing gas into contact with an aqueous solution containing at least one amine compound of the general formula ?1! ##STR1## wherein R.sup.1 to R.sup.8 may be the same or different and each represent a hydrogen atom or an alkyl group of 1 to 4 carbon atoms, and m is 0 or 1. The method of the present invention makes it possible to remove carbon dioxide efficiently. In particular, since carbon dioxide can be easily desorbed by heating the aqueous solution having absorbed carbon dioxide, the thermal energy required for regeneration of the aqueous solution can be reduced.

Abstract: This invention provides a process for effecting desulfurization and decarbonation in two stages. A gas containing sulfur oxides and carbon dioxide is first treated in a desulfurization step so as to cause sulfur oxides to be absorbed in the form of calcium-sulfur oxide compounds; the gas is then treated in a decarbonation step so as to cause carbon dioxide and any sulfur oxides escaping from the desulfurization step to be absorbed in the form of amine salts; the absorbing solution containing the amine salts is regenerated by liberating carbon dioxide therefrom; a part of the regenerated absorbing solution is recycled to the decarbonation step while the remainder of the absorbing solution is fed to a secondary regeneration step where it is treated with a basic calcium substance to regenerate basic amine compound for recycle and to form a solid containing calcium-sulfur oxide compounds and calcium carbonate.

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: This invention relates to methods for the removal of hydrogen sulfide from various gases containing hydrogen sulfide. In order to remove hydrogen sulfide, an aqueous solution containing a di(lower alkyl)amino-(lower alkanol) or triethylenediamine is used. In order to remove hydrogen sulfide selectively from gases containing carbon dioxide and hydrogen sulfide, an aqueous solution containing tert-butyldiethanolamine, triisopropanolamine, triethylenediamine or 2-dimethylamino-2-methyl-1-propanol is used. In order to remove both carbon dioxide and hydrogen sulfide from gases containing carbon dioxide and hydrogen sulfide, an aqueous solution containing a mono(lower alkyl)amino-(lower alkanol) is used.

Abstract: This invention provides a method for the removal of CO.sub.2 present in combustion exhaust gas which comprises bringing combustion exhaust gas at atmospheric pressure into contact with a mixed aqueous solution containing 100 parts by weight of an amino acid metal salt (X), 1 to 25 parts by weight of piperazine (Y), and optionally a copper compound in such an amount as to give a divalent copper ion concentration of 10 to 1,000 ppm based on the mixed aqueous solution, the amino acid metal salt being of the general formulaCH.sub.3 NR.sup.1 CHR.sup.2 COOM (1)wherein R.sup.1 and R.sup.2 represent hydrogen atoms or lower alkyl groups, provided that R.sup.2 is a lower alkyl group when R.sup.1 is a hydrogen atom, and R.sup.2 is a hydrogen atom when R.sup.1 is a lower alkyl group, and M represents an alkali metal.Potassium dimethylaminoacetate is a preferred amino acid metal salt (X).

Abstract: This invention relates to a process for the removal of carbon dioxide from gases which comprises the carbon dioxide absorption step of bringing a gas having a carbon dioxide partial pressure in the range of 0.3 to 50 atmospheres (absolute pressure) into gas-liquid contact with an absorbing fluid comprising an aqueous solution containing an amine compound of the general formula ?1!R.sup.1 R.sup.2 NCH.sub.2 CH(OH)CH.sub.2 OH ?1!where R.sup.1 and R.sup.2 independently represent lower alkyl groups of 1 to 3 carbon atoms, so as to produce a treated gas having a reduced carbon dioxide content and a carbon dioxide-rich absorbing fluid; and the regeneration step of liberating carbon dioxide from the carbon dioxide-rich absorbing fluid by (1) flashing at atmospheric pressure or in the vicinity of atmospheric pressure and/or (2) steam stripping, so that a carbon dioxide-lean absorbing fluid is regenerated and recycled for use in the carbon dioxide absorption step.

Abstract: A method for removing carbon dioxide from a combustion exhaust gas under atmospheric pressure by the use of a mixed solution of a specific amine compound X having an alcoholic hydroxyl group and a primary amino group which is bonded to a tertiary carbon atom having two unsubstituted alkyl groups and another amine compound Y being a diaminotoluene (DAT) selected from the group consisting of 2,3-DAT, 2,4-DAT, 2,5-DAT, 2,6-DAT, 3,4-DAT and 3,5-DAT.

Abstract: A process for removing both CO.sub.2 and NO.sub.x from combustion gases consists, first, in cooling a combustion gas to 50 to 100.degree. C. and adding ozone to oxidize NO in the combustion gas to NO.sub.2. Then in a CO.sub.2 removal step, the gas is brought into contact with an aqueous solution of an alcoholic hydroxyl-containing secondary- or tertiary-amine to remove NO.sub.2 together with CO.sub.2 from the gas.

Abstract: This invention relates to the process for removing CO.sub.2 from CO.sub.2 -containing gas such as combustion gas. For example, it is the process for removing CO.sub.2 from combustion gas through the contact of the gas at the atmospheric pressure with an aqueous solution of an amine represented by the general formula R.sup.1 NHC(CH.sub.3).sub.2 CH.sub.2 OH in which R.sup.1 is a lower alkyl group having 1-4 carbon atoms, or an aqueous solution containing both an amine represented by the general formula R.sub.2 CHR.sub.3 NHCH.sub.2 CH.sub.2 OH in which R.sup.2 is a hydrogen atom or a lower alkyl group having 1-4 carbon atoms and R.sup.3 is a hydrogen atom or methyl group and a piperazine compound selected from the group consisting of piperazine, 2-methylpiperazine, 2,3-dimethylpiperazine, and 2,5-dimethylpiperazine, or an mixed aqueous amine solution containing a secondary amine and a tertiary amine at concentrations of 10-45% by weight each, or an aqueous solution of a piperazine derivative.

Abstract: This invention relates to methods for the removal of hydrogen sulfide from various gases containing hydrogen sulfide. In order to remove hydrogen sulfide, an aqueous solution containing a di(lower alkyl)amino-(lower alkanol) or triethylenediamine is used. In order to remove hydrogen sulfide selectively from gases containing carbon dioxide and hydrogen sulfide, an aqueous solution containing tert-butyldiethanolamine, triisopropanolamine, triethylenediamine or 2-dimethylamino-2-methyl-1-propanol is used. In order to remove both carbon dioxide and hydrogen sulfide from gases containing carbon dioxide and hydrogen sulfide, an aqueous solution containing a mono(lower alkyl)amino-(lower alkanol) is used.

Abstract: A heat pipe includes: a pipe barrel; and a large number of fins disposed on the peripheral surface of the pipe barrel at least on either a heat collecting section side or a radiating section side, each of the fins is attached to the pipe barrel on a plane perpendicular to the axis of the pipe barrel, and each of the fins is composed of a metal plate and net-like material adhered to both surfaces of the metal plate.A heat exchanger of gas-liquid contacting plate type includes: a plurality of heat transfer plates, disposed vertically at certain intervals, defining air flow passages therebetween which allow air to rise, and each of the plates has a heat medium flowing passage thereinside for allowing a heat medium to flow therethrough while the side surfaces of each of the heat transfer plates, which define the air flow passages, are adhered with nets for allowing a liquid to flow downward along the nets and plates.

Abstract: A process for removing CO.sub.2 from a combustion gas which comprises removing CO.sub.2 from the combustion gas through contact of an aqueous hindered amine solution used as a CO.sub.2 absorbent solution with the combustion gas at atmospheric pressure and then, in a regeneration column, liberating CO.sub.2 from the absorbent solution that has absorbed CO.sub.2 by heating it and thereby regenerating the absorbent solution. The process further comprises a partial absorbent solution regeneration step in at least one stage wherein the absorbent solution that has absorbed CO.sub.2 is heated through heat exchange with a high-temperature regenerated absorbent solution and part of the CO.sub.2 that is liberated is separated from the absorbent solution. Following this, according to the necessity, part of the partially regenerated absorbent solution thus obtained is returned to the step of removing CO.sub.2 from the combustion gas for use as part of the CO.sub.

Abstract: An apparatus for gas-liquid contact in which tubular structure fillers having a cross section of any of various shapes and having straight tubular portions are arranged in a substantially vertical direction in the form of plural steps so that the gas-liquid contact surfaces of the fillers may be parallel with the flow of the gas,the apparatus for gas-liquid contact being characterized in that the gas-liquid contact surfaces comprise rough surface portions, porous surface portions, meshes or plates to which meshes adhere, or there is interposed, between the plural steps of the fillers, a dispersing plate for receiving the liquid downward coming from the site above the fillers, dispersing the liquid, and allowing the liquid to downward flow.