A method of treating oil and gas streams to remove total organic sulfur or total acid gas including the step of treating the gas stream with a solution of an amine, physical solvent, and water wherein the amine solution may optionally also contain an activator.

The invention pertains to processes for separating gases, acid gas, hydrocarbons, air gases, or combinations thereof. The processes may employ using a liquid phase cloud point with or without subsequent liquid-liquid separation. In some embodiments membranes can be employed with reverse osmosis to regenerate a solvent and/or an antisolvent. In some embodiments thermal switching phase changes may be employed during absorption or desorption to facilitate separation.

Treatment of streams containing hydrogen and/or hydrocarbons, and in one non-limiting embodiment refinery distillates, with alkyl carbonates, such as dimethylcarbonate, alone or together with at least one solvent results in reduction or removal of hydrogen sulfide (H.sub.2S) that is present to give easily removed alkyl sulfides and/or mercaptans. In one non-limiting embodiment, the treatment converts the original hydrogen sulfide into alkyl sulfides and/or mercaptans that can be extracted from the stream with caustic solutions, mercaptan scavengers, solid absorbents such as clay or activated carbon or liquid absorbents such as amine-aldehyde condensates and/or aqueous aldehydes.

In one aspect, the invention provides a method for the capture of at least one acid gas in a composition, the release of said gas from said composition, and the subsequent regeneration of said composition for re-use, said method comprising performing, in order, the steps of: (a) capturing the at least one acid gas by contacting said at least one gas with a capture composition comprising at least one salt of a carboxylic acid and at least one water-miscible non-aqueous solvent; (b) releasing said at least one acid gas by adding at least one protic solvent or agent to said composition; and (c) regenerating the capture composition by partial or complete removal of said added protic solvent or agent from said composition. Optionally, said capture composition comprising at least one salt of a carboxylic acid and at least one water-miscible non-aqueous solvent additionally comprises water or another protic solvent. In another aspect, the invention envisages a composition which additionally comprises at least one protic solvent or agent and release of the at least one acid gas is achieved solely by subjecting the composition to the application of heat or stripping with a stream of air. The method is typically applied to the capture and subsequent release of carbon dioxide, and offers a convenient and simple process which uses inexpensive consumables and offers significant advantages over the methods of the prior art.

A liquid/gas contactor unit includes a unit housing having a liquid inlet and a liquid outlet, and an air inlet and an air outlet. The liquid inlet and the liquid outlet are configured to flow liquid through the unit housing in a gravity liquid flow direction. The air inlet and the air outlet are configured to flow air through the unit housing in an air flow direction. A plurality of porous media layers are contained within the unit housing and along the air flow channel. Each porous media layer is separated from an adjacent porous media layer by an air gap. Each porous media layer has opposing major surfaces separated by a thickness. The opposing major surfaces are orthogonal to the gravity liquid flow direction.

A method of treating oil and gas streams including hydrogen sulfide (H.sub.2S) comprising treating the gas stream with an aqueous solution of an amine and a physical solvent which, when mixed in equal mass ratio with the amine or amine mixture, display a dielectric constant of at least about 20, wherein the pKa of the amine is at least about 9.0 and the amine boiling point is at least 200 C.

A compound of the general formula (I) ##STR00001##
in which R.sub.1, R.sub.2 and R.sub.3 are independently selected from C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.4 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; each R.sub.5 is independently selected from hydrogen, C.sub.1-4-alkyl and C.sub.1-4-hydroxyalkyl; m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is an integer from 0 to 10. A preferred compound of the formula (I) is 2-(2-tert-butylaminoethoxy)ethylamine. Absorbents comprising a compound of the formula (I) have rapid absorption of carbon dioxide from fluid streams and are also suitable for processes for the simultaneous removal of H.sub.2S and CO.sub.2, where given H.sub.2S limits have to be observed but complete removal of CO.sub.2 is not required.

A method for removing SO.sub.x from a gas by using a polyol composite solution is provided. The polyol composite solution is made by mixing a polyol with an organic acid and/or organic acid salt, the polyol composite solution is brought into contact with the gas containing SO.sub.x to absorb the SO.sub.x in the gas, wherein x=2 and/or 3, and the polyol refers to an organic compound other than ethylene glycol and polyethylene glycol, which contains simultaneously two or more than two hydroxyl groups in a same organic molecule.

A hybrid method for capturing CO.sub.2 from a gas mixture is provided, comprising a step of contacting the CO.sub.2 containing gas mixture with a slurry consisting of a liquid medium, imidazole or imidazole derivative(s), and a metal-organic framework material (MOFs). For the slurry system, the mass fraction of the imidazole or imidazole derivative(s) in it ranging from 2 to 50% and the mass fraction of the metal-organic framework material in it ranging from 5 to 25%. In the technical solution provided in the present invention, through combining absorptive separation by the liquid solution in which the imidazole or imidazole derivative(s) is dissolved, adsorption separation by the MOF material suspended in the solution, and selective permeation separation by a liquid medium film forms on the outside surface of the suspended MOFs, an absorption-adsorption hybrid separation effect for CO.sub.2 gas mixtures is efficiently achieved. In the CO.sub.2 capture method provided in the present invention, conventional absorption separation and adsorptive separation technologies are effectively combined, furthermore, the addition of imidazole or imidazole derivative(s) substantially increases both the CO.sub.2 capture ability and capture amount of the MOFs/liquid slurry, showing a great potential in industrial applications.

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