A chemical composition for use in degassing of vessels is taught, said chemical composition including 1-10% by weight of an oxyalkylated dodecyl thiol; and 1-20% by weight of an alkyl di-substituted 9-decenamide. A method is further provided for degassing a vessel. The method includes charging said vessel with chemical composition and a carrier medium, wherein said chemical composition comprises 1-10% by weight of an oxyalkylated dodecyl thiol and 1-20% by weight of an alkyl di-substituted 9-decenamide.

A system for oxidizing nitrogen monoxide (NO) contained in exhaust gas injects a liquid oxidizing agent into the exhaust gas and simultaneously removes nitrogen oxides and sulfur oxides from exhaust gas using an organic catalyst. The system includes an absorption tank for storing an absorption solution containing an organic catalyst, the absorption tank communicating with an oxygen supply pipe for supplying oxygen-containing gas to the absorption tank; an absorption tower, extending upward from the absorption tank, through which the exhaust gas flows from an exhaust gas inlet duct to an exhaust gas outlet; a first injection unit to inject the absorption solution into the absorption tower; a second injection unit to inject an oxidizing agent solution into at least one of the inlet duct and the absorption tower; and an oxidizing agent supply unit for supplying the oxidizing agent solution to the second injection unit.

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 carbon dioxide absorbent of an embodiment includes a chain amine, a cyclic amine, and an acid. The chain amine is a compound expressed by Formula (1) of FIG. 1. R.sup.1 in Formula (1) is hydrogen or an alkyl chain having at least one hydroxyl group and 1 to 7 carbon atoms. R.sup.2 in Formula (1) is an alkyl chain having at least one hydroxyl group and 1 to 7 carbon atoms. R.sup.3 in Formula (1) is hydrogen, a straight alkyl chain having 1 to 7 carbon atoms, a branched alkyl chain having 1 to 7 carbon atoms, or a cyclic alkyl chain having 5 to 7 carbon atoms.

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.

Solvent absorption processes for separating components of an impure feed gas are disclosed. The processes involve two stages of gas purification. The acid gases including hydrogen sulfide, carbon dioxide and other sulfur compounds are simultaneously removed from the feed gas by contact with a physical solvent in two stages. The subject matter disclosed provides improved processes to reduce the operating costs of the system.

A method for treating a fluorine element-containing exhaust gas including a dilution step of diluting a fluorine element-containing exhaust gas (a) with an inert gas so as to have a fluorine gas (F.sub.2) concentration of 25% by volume or less to prepare a diluted gas (b) and a water absorption step of contacting the diluted gas (b) with water to obtain a treated gas (c).

A method and apparatus for recycling streams in a separations process comprising: determining a measured reading of a parameter of the separations processor is in a suboptimal range; separating, via a separation unit having a volume of contact fluid, the inert gas from the pollutant gas in the inlet flue gas stream to form a clean gas stream and a purified pollutant gas stream; removing at least 1% of the volume of contact fluid to form a removed volume of contact liquid; performing some unit operations on the removed volume of contact fluid; injecting the clean gas stream into the inlet flue gas stream to form a flue gas stream of lower pollutant concentration; and, repeating at progressively lower pollutant concentration, as the inlet stream until the processor determines that a measured reading of the parameter has been returned to a substantially optimal range.

Solvent absorption processes for separating components of an impure feed gas are disclosed. The processes involve two stages of gas purification. The acid gases including hydrogen sulfide, carbon dioxide and other sulfur compounds are simultaneously removed from the feed gas by contact with a physical solvent in two stages. The subject matter disclosed provide improved processes and apparatus to reduce the operating costs of the system.

A process for separating a vapor from a gas is disclosed. A cryogenic liquid is provided to an inlet of a froth flotation device. A carrier gas is provided to a gas distributor of the froth flotation device. The carrier gas comprises a product vapor. Bubbles of the carrier gas are produced and passed through the cryogenic liquid in the froth flotation device. A portion of the product vapor desublimates, condenses, crystallizes, or a combination thereof to produce a solid product and a product-depleted carrier gas. Bubbles of the product-depleted carrier gas collect the solid product as a froth concentrate. The froth concentrate is removed by overflowing out of the froth flotation device.