A system and method for processing unconditioned syngas first removes solids and semi-volatile organic compounds (SVOC), then removes volatile organic compounds (VOC), and then removes at least one sulfur containing compound from the syngas. Additional processing may be performed depending on such factors as the source of syngas being processed, the products, byproducts and intermediate products desired to be formed, captured or recycled and environmental considerations.

The absorption agent of the present invention contains water, an amine compound, and an organic solvent, and a value obtained by subtracting a solubility parameter of the organic solvent from a solubility parameter of the amine compound is 1.1 (cal/cm.sup.3).sup.1/2 or more and 4.2 (cal/cm.sup.3).sup.1/2 or less. The method for separation and recovery of an acidic compound of the present invention includes the steps of: bringing a mixed gas containing an acidic compound into contact with an absorption agent containing water, an amine compound, and an organic solvent to absorb the acidic compound into the absorption agent; causing the absorption agent that has absorbed the acidic compound to be phase-separated into a first phase containing the acidic compound in a high content and a second phase containing the acidic compound in a low content; and heating the first phase to release the acidic compound from the first phase.

A process for absorbing carbon dioxide from a gas stream containing carbon dioxide, including the steps of contacting the gas stream with an aqueous composition including a substituted heteroaromatic compound having a six-membered heteroaromatic ring with from 1 to 3 nitrogen atoms in the heteroaromatic ring and at least one substituent wherein at least one of the substituents is of formula —R.sup.1NH.sub.2 wherein R.sup.1 is selected from C.sub.1 to C.sub.6 alkylene and ethers of formula —R.sup.2—O—R.sup.3— wherein R.sup.2 and R.sup.3 are C.sub.1 to C.sub.3 alkylene.

A scrubbing solution for removing contaminants, including particularly hydrogen sulfide, from a fluid. The scrubbing solution includes at least one scrubbing reagent which has a primary or secondary amine and an acid, which may be phosphoric acid. The fluid being scrubbed is passed through the scrubbing solution. The contaminants react with the scrubbing reagent securing them in the scrubbing solution. The fluid being scrubbed and the scrubbing solution are then separated. The scrubbing solution is heated and, if the scrubbing solution is under pressure, the pressure is reduced. The acid facilitates thorough removal of the contaminants, and especially the hydrogen sulfide, from the scrubbing solution. The scrubbing solution is then ready for reuse. Because the scrubbing solution is rendered substantially free of hydrogen sulfides, it can absorb other sulfide contaminants that might not otherwise be absorbed.

A system for carbon dioxide capture from a gas mixture comprises an absorber that receives a lean solvent system stream (containing a chemical solvent, physical-solvent, and water) from the stripper, a stripper that receives the rich solvent stream from the absorber and produces the product carbon dioxide and the lean solvent through the use of a reboiler in fluid communication with a lower portion of the stripper, a condenser in fluid communication with a vapor outlet of the stripper, a cross-exchanger in fluid communication with a rich solvent system outlet from the absorber and a rich solvent system inlet on the stripper, and a splitter. The splitter is configured to separate the rich solvent system stream into a first portion and second portion, where the first portion directly passes to the stripper and the second portion passes through the cross-exchanger prior to passing to the stripper.

The invention provides a process for regenerating a liquid absorbent, including: contacting the liquid absorbent with a hydrophobic medium, wherein the liquid absorbent includes at least one amine of Formula (I)

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and degradation product thereof including at least one imine of Formula (II),

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wherein each Ar is independently an aromatic group and each R is independently selected from hydrogen, an organyl group and NH2; and selectively extracting the degradation product into or through the hydrophobic medium.

Disclosed is a process for regenerating a hybrid solvent used to remove contaminants from a fluid stream and to provide an improved yield of purified fluid. Said process comprises a purification unit (12) and at least one regeneration unit (40) wherein make-up water (72) is added to the regenerated lean hybrid solvent (55) prior to reuse in the first purification unit and no water is recycled into the regeneration unit.

A system and method for processing unconditioned syngas first removes solids and semi-volatile organic compounds (SVOC), then removes volatile organic compounds (VOC), and then removes at least one sulfur containing compound from the syngas. Additional processing may be performed depending on such factors as the source of syngas being processed, the products, byproducts and intermediate products desired to be formed, captured or recycled and environmental considerations.

An aqueous CO2 absorbent comprising a combination of 2-amino-2-methyl-1-propanol (AMP) and 3-aminopropanol (AP), or AMP and 4-aminobutanol (AB), is described. A method for capturing CO2 from a CO2 containing gas using the mentioned absorbent, and the use of a combination of AMP and AP, or a combination of AMP and AB are also described.

An aqueous liquid sorbent suitable for use in separating a target gas from a mixture of gases in a rotating packed bed gas capture system, comprising a first amine compound, a second amine compound and water, wherein the sorbent comprises at least 16 wt % of the first amine compound and at least 51 wt % of total amine compounds, the first amine compound has a reaction rate with the target gas that is greater than the reaction rate of the second amine with the target gas, and the second amine compound has a solubility in water that is greater than the solubility of the first amine compound in water.