The invention provides the use of hydroxide ions as a heat source in a CO.sub.2 absorption process.

A CO.sub.2 cycle power generation unit including a power generation turbine using a CO.sub.2 fluid as a drive fluid, a CO.sub.2 first compression device pressurizing the CO.sub.2 fluid after driving the power generation turbine, and a combustor combusting a light hydrocarbon gas containing methane as fuel using oxygen supplied from an air separation device in a state of mixing the pressurized and heated CO.sub.2 fluids, wherein a combustion gas obtained by the combustor is supplied to the power generation turbine as a drive fluid, and a CO.sub.2 recovery unit recovering CO.sub.2 from an exhaust gas emitted by fuel combustion in an external combustion unit. A part of the CO.sub.2 fluid emitted from the CO.sub.2 cycle power generation unit and CO.sub.2 recovered by the CO.sub.2 recovery unit are supplied to a CO.sub.2 reception unit. Energy obtained by the CO.sub.2 cycle power generation unit is supplied to the CO.sub.2 recovery unit.

A process for hydrotreating a feed stream comprising a biorenewable feedstock is disclosed. The process comprises hydrotreating the feed stream in the presence of a hydrotreating hydrogen stream and a hydrotreating catalyst to provide a hydrotreated stream. The hydrotreated stream is separated into a hydrotreated liquid stream and a hydrotreated gas stream. The hydrotreated liquid stream is subjected to stripping to provide a stripper off-gas stream. At least a portion of the stripper off-gas stream is contacted with a caustic stream to provide a sulfur-lean gas stream and a sulfur-rich caustic stream. The sulfur-rich caustic stream is further treated to provide a treated gas stream.

Processes for separating CO from CO.sub.2 in flue gas streams from partial oxidation regenerator in FCC processes, as well as reducing the sulfur content of the flue gas stream are described. The processes involve separating the cooled reactor effluent stream into a CO.sub.2 product stream, the CO.sub.2 recycle stream, and a CO product stream. The processes may incorporate either dry sorbent injection (DSI) units or wet gas scrubbing units to remove sulfur compounds. The separation processes can utilize cryogenic fractionation, pressure swing adsorption (PSA) processes including vacuum PSA, and temperature swing adsorption (TSA) processes. The flue gas stream can be used to preheat the CO.sub.2 recycle stream.

In accordance with exemplary inventive practice, a catalytic system and a temperature swing adsorption system are thermally integrated. The temperature range of the adsorption system is lower than the catalyst operating temperature. Benefits of inventive practice include reduction of total energy consumption and of generated waste-heat. Total energy consumption is reduced by transferring some of the waste-heat generated by the catalytic system into the adsorption system during the sorbent heat-up portion of the sorbent regeneration cycle. The heat is transferred using a thermal reservoir, which accumulates heat from the catalytic apparatus and transfers it to the adsorption apparatus at a later time, and which is repeatedly cycled as the sorbent is cycled. The catalytic system and the adsorption system can be inventively integrated in various ways to reduce the total energy consumed, and/or to modify the sorbent regeneration temperature profile, and/or to obtain an optimum power load profile.

Apparatus and methods for denitrification and desulfurization of and dust removal from an FCC tail gas by an ammonia-based process. The apparatus may include a first-stage waste heat recovery system, a denitrification system, a dust removal and desulfurization system, a tail gas exhaust system, and an ammonium sulfate post-processing system. The dust removal and desulfurization system may include a dedusting tower and an absorption tower disposed separately. The top and the bottom of the absorption tower may be connected respectively to the tail gas exhaust system and the ammonium sulfate post-processing system. The absorption tower may include sequentially, from bottom to top, an oxidation section, an absorption section, and a fine particulate control section. The methods may be implemented with the apparatus.

Provided are a reclaimer 51 that introduces, through a branch line L.sub.11, and stores a part 17a of an absorbent 17 regenerated in a regenerator of a recovery unit that recovers CO.sub.2 or H.sub.2S in a gas, a first alkaline agent supply section 53A that supplies an alkaline agent 52 to the reclaimer 51, a heating section 54 that heats the absorbent 17 stored in the reclaimer 51 and to which the alkaline agent 52 has been mixed to obtain recovered vapor 61, a first vapor cooler 55A that cools the recovered vapor 61 discharged from the reclaimer 51 through a vapor line L.sub.12, a first gas-liquid separator 56A that separates a coexisting substance 62 entrained in the cooled recovered vapor 61 into a recovered absorption agent vapor (gas) 17b and the liquid coexisting substance 62 by gas-liquid separation, and an introduction line L.sub.13 that introduces the recovered absorption agent vapor 17b separated in the first gas-liquid separator 56A into a regenerator 20.

A method for treating flue gas including sulphur oxides and nitrogen oxides includes: cooling the furnace outlet flue gas; contacting it with a sulphur oxide neutralization agent, reducing the sulphur oxides by desulphurization reactions, and obtaining residues; separating the residues from the flue gas; reheating the flue gas; injecting a nitrogen oxide neutralization agent therein; and placing the reheated flue gas and the nitrogen oxide neutralization agent in contact with a catalyst, reducing the nitrogen oxides by denitrification reactions, the cooling of the flue gas achieved by reheating, inside the same heat exchanger, the flue gas separated from the desulphurization residues. The reheated flue gas is mixed, after injecting the nitrogen oxide neutralization agent, with the flue gas cooled after being placed in contact with the sulphur oxide neutralization agent, the separation of the residues and the contact with the catalyst being carried out inside a single separation device.

A method and an integrated system for reducing CO.sub.2 emissions in industrial processes. The method and integrated system (100) capture carbon dioxide (CO.sub.2) gas from a first gas stream (104) with a chemical absorbent to produce a second gas stream (106) having a higher concentration of carbon monoxide (CO) gas and a lower concentration of CO.sub.2 gas as compared to first gas stream. The CO gas in the second gas stream is used to produce C.sub.5 to C.sub.20 hydrocarbons in an exothermic reaction (108) with hydrogen (H.sub.2) gas (138). At least a portion of the heat generated in the exothermic reaction is used to regenerate the chemical absorbent with the liberation of the CO.sub.2 gas (128) captured from the first gas stream. Heat captured during the exothermic reaction can, optionally, first be used to generate electricity, wherein the heat remaining after generating electricity is used to thermally regenerate the chemical absorbent.

Processes and apparatuses for treating a sour synthesis gas are provided. The process comprises passing the sour synthesis gas stream to an acid gas removal unit to provide a treated synthesis gas stream and a CO.sub.2 rich stream. At least a portion of the CO.sub.2 rich stream is passed to a thermal oxidizer unit to provide a treated CO.sub.2 gas stream. At least a portion of the treated synthesis gas stream is passed to a pressure swing adsorption unit to obtain a purified hydrogen stream and a tail gas stream. At least a portion of the tail gas stream is passed to the thermal oxidizer unit.