The present invention relates to an apparatus and method for recovering carbon dioxide (hereinafter also referred to as “CO.sub.2”) contained in a combustion exhaust gas, and more specifically relates to: an apparatus and method for reactively absorbing CO.sub.2 contained in a combustion exhaust gas into an amine compound-containing absorption liquid; an apparatus and method for desorbing CO.sub.2 contained in an amine compound-containing absorption liquid from the amine compound-containing absorption liquid; an apparatus and method for evaporating and separating impurities from the amine compound-containing absorption liquid containing the impurities; an apparatus and method for performing a pretreatment such as desulfurization, dust removal, and cooling on a combustion exhaust gas; and a carbon dioxide-recovering apparatus and method utilizing the above apparatuses and methods.

A granular sorption material including a plurality of porous granules formed by buildup agglomeration for separation, especially absorption, of harmful gases, especially of SO.sub.X and/or HCl, from offgases of thermal processes. The granules containing greater than 80% by weight, and preferably greater than 95% by weight, of Ca(OH).sub.2 and/or CaCO.sub.3 based on the dry mass. The granules having a dry apparent density ρ, determined by means of an apparent density pycnometer, of 0.5 to 1.2 kg/dm.sup.3, preferably 0.7 to 1.1 kg/dm.sup.3, and/or a porosity of 45% to 73% by volume, preferably 55% to 65% by volume, and have especially been increased in porosity. A process for producing the granular sorption material, in which pores are introduced into the granules by means of a porosity agent during the production.

A flue gas desulfurization unit is converted from operating with lime or magnesium enhanced lime under inhibited oxidation into a unit that operates using limestone under inhibited oxidation conditions. A ball mill grinding unit may be installed to crush the limestone thereby producing a suspended slurry of fine limestone particles which is pumped to the reaction vessel. When installed, the ball mill may be installed in the process immediately downstream of the existing slaking equipment. The suspended solution may be maintained at a pH in the range of 3.0 to 6.5, optimally at approximately 5.0 to increase the dissolution rate of the limestone reagent produced by the ball mill. The post-conversion process may also require the addition of organic acids and oxidation inhibitors to achieve better SO.sub.2 removal from the flue gas.

Sweep-based gas separation processes for reducing carbon dioxide emissions from gas-fired power plants. The invention involves at least two compression steps, a combustion step, a carbon dioxide capture step, a power generate step, and a sweep-based membrane separation step. One of the compression steps is used to produce a low-pressure, low-temperature compressed stream that is sent for treatment in the carbon dioxide capture step, thereby avoiding the need to expend large amounts of energy to cool an otherwise hot compressed stream from a typical compressor that produces a high-pressure stream, usually at 20-30 bar or more.

A reactor system for conducting an adsorption/desorption swing process comprising of at least o adsorption reactor; at least one desorption reactor and means for transporting a particulate adsorbent material between the at least one adsorption reactor and the at least one desorption reactor.

The present invention discloses a method for removing carbon dioxide from a reaction gas. The present invention fully utilizes the available heat in each part of the carbon dioxide removal system to reduce external heat exchange, and thereby significantly reduces the carbon dioxide content in the gas returned to the reactor, and also greatly reduces the steam consumption during the regeneration of the rich decarburizing solution. The present invention also discloses a system for removing carbon dioxide from the reaction gas and use thereof.

A process for treating effluent streams in a renewable transportation fuel production process is described. One or more of the sour water stream and an acid gas stream are treated directly in thermal oxidation section. The process allows the elimination or size reduction of a sour water stripper unit, waste water treatment plant, and sulfur recovery unit.

The present invention relates to a copolymer containing a constitutional unit derived from acrylic acid cesium salt or acrylic acid rubidium salt and a constitutional unit derived from vinyl alcohol, a resin composition containing the copolymer, a carbon dioxide gas separation membrane which can be manufactured with the resin composition, a carbon dioxide gas separation membrane module having the separation membrane, and a carbon dioxide gas separation apparatus including at least one type of the module.

Disclosed are methods and systems for removing submicron particles from a gas stream, in particular from urea prilling off-gas, wherein a Venturi ejector is used. A method comprises contacting a gas stream containing submicron particles in a Venturi ejector with an injected high velocity scrubbing liquid to provide a pumping action, wherein the scrubbing liquid has an initial velocity of at least 25 m/s and wherein the ratio of scrubbing liquid and gas flow is between 0.0005 and 0.0015 (m.sup.3/h)/(m.sup.3/h).

A mixed salt composition adapted for use as a sorbent for carbon dioxide removal from a gaseous stream is provided, the composition being in solid form and including magnesium oxide, an alkali metal carbonate, and an alkali metal nitrate, wherein the composition has a molar excess of magnesium characterized by a Mg:X atomic ratio of at least about 3:1, wherein X is the alkali metal. A process for preparing the mixed salt is also provided, the process including mixing a magnesium salt with a solution comprising alkali metal ions, carbonate ions, and nitrate ions to form a slurry or colloid including a solid mixed salt including magnesium carbonate; separating the solid mixed salt from the slurry or colloid to form a wet cake; drying the wet cake to form a dry cake including the solid mixed salt; and calcining the dry cake to form a mixed salt sorbent.