An oxidation-reduction desulfurization system includes a reactor vessel with sour gas inlet at the bottom and a gas outlet at the top. A primary stage phase separator includes a vertically-oriented pipe with an inlet located inside the reactor vessel. The ratio of the reactor vessel diameter to the pipe inlet diameter is in a range of 2:1 to 5:1. Surface foam and non-gaseous multi-phase mixture including emulsion flow into a partially gas-filled upper section of the vertically-oriented pipe and freefall to a lower level, thereby facilitating mechanical breaking of the foam and the emulsion. A secondary stage phase separator connected to the gas outlet separates non-gaseous surge from sweet gas. Valves and a controller automatically maintain target levels of the non-gaseous multi-phase mixture and non-gaseous surge.

A process and an apparatus are disclosed for a compact processing assembly to remove C.sub.5 and heavier hydrocarbon components from a hydrocarbon gas stream. The hydrocarbon gas stream is expanded to lower pressure and supplied to the processing assembly between an absorbing means and a mass transfer means. A distillation vapor stream is collected from the upper region of the absorbing means and cooled in a first heat and mass transfer means inside the processing assembly to partially condense it, forming a residual vapor stream and a condensed stream. The condensed stream is supplied to the absorbing means at its top feed point. A distillation liquid stream is collected from the lower region of the mass transfer means and directed into a second heat and mass transfer means inside the processing assembly to heat it and strip out its volatile components.

An absorbent for removing carbon dioxide from a fluid stream, comprising an aqueous solution a) of an amine of the general formula (I)

##STR00001##

in which R.sub.1, R.sub.2 and R.sub.3 are each 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.1-4alkyl 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; X is OH or NH(CR.sub.1R.sub.2R.sub.3); m is 2, 3, 4 or 5; n is 2, 3, 4 or 5; and o is 0 or 1; and b) at least one activator selected from b1) a sterically unhindered primary amine and/or a sterically unhindered secondary amine; and a carboanhydrase. The absorbent allows rapid absorption of carbon dioxide from fluid streams.

The invention relates to a method for treating a hydrocarbon gas stream containing H2S and mercaptans, in which dialkyldisulfides are produced then removed by hydrogenation, as well as a device for carrying out said method.

An absorbent for the selective removal of hydrogen sulfide from a fluid stream comprising carbon dioxide and hydrogen sulfide, wherein the absorbent contains an aqueous solution, comprising: a) an amine or a mixture of amines of the general formula (I) wherein R.sup.1 is C.sub.1-C.sub.5-alkyl; R.sup.2 is C.sub.1-C.sub.5-alkyl; R.sup.3 is selected from hydrogen and C.sub.1-C.sub.5-alkyl; x is an integer from 2 to 10; and b) an ether or a mixture of ethers of the general formula (II): R.sup.4—[O—CH.sub.2—CH.sub.2].sub.y—OH; wherein R.sup.4 is C.sub.1-C.sub.5-alkyl; and y is an integer from 2 to 10; wherein R.sup.1 and R.sup.4 are identical; wherein the mass ratio of b) to a) is from 0.08 to 0.5. The absorbent is suitable for the selective removal of hydrogen sulfide from a fluid stream comprising carbon dioxide and hydrogen sulfide. The absorbent has a reduced tendency for phase separation at temperatures falling within the usual range of regeneration temperatures for the aqueous amine mixtures and is easily obtainable. ##STR00001##

A method of removing impurities from a natural gas stream. A selective solvent is provided that absorbs a first impurity at a first rate and a second impurity at a second rate that is slower than the first rate. The solvent is cooled to a temperature below 60° F. to provide a cooled solvent. The cooled solvent is contacted with the natural gas stream, thereby generating a rich solvent that includes the first impurity. The rich solvent is removed from the natural gas stream, wherein an amount of the first impurity remaining in the natural gas stream is below a sales gas requirement.

A method for treating liquefied hydrocarbons including acid gases to remove said acid gases while minimizing loss of amine species, said method comprising the steps of contacting the liquefied hydrocarbons with an absorbent aqueous solution of a first amine compound, the first amine compound having the structure: ##STR00001##
wherein R.sub.1 is propane-2,3-diol; R.sub.2 is hydrogen, methyl ethyl, 2-hydroxyethyl, or propane-2,3-diol; and R.sub.3 is hydrogen, methyl, ethyl, 2-hydroxyethyl or propane-2,3-diol.

In an aspect, a method is disclosed that includes contacting a composition with an aqueous solution to yield a mixture, where the composition includes one or more of animal fats, animal oils, plant fats, plant oils, vegetable fats, vegetable oils, greases, and used cooking oil, about 5 wt. % or more of free fatty acids, about 10 wppm or more of total metals, about 8 wppm or more phosphorus, about 20 wppm or more of nitrogen, and the aqueous solution includes ((NH.sub.4).sub.2H.sub.2EDTA, (NH.sub.4).sub.4EDTA, a monoammonium salt of diethylenetriaminepentaacetic acid, a diammonium salt of diethylenetriaminepentaacetic acid, a triammonium salt of diethylenetriaminepentaacetic acid, a tetraammonium salt of diethylenetriaminepentaacetic acid, (NH.sub.4).sub.5DTPA, a combination of citric acid and Na.sub.4EDTA, a combination of citric acid and Na.sub.2H.sub.2EDTA, a combination of citric acid and a monosodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a disodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a trisodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and a tetrasodium salt of diethylenetriaminepentaacetic acid, a combination of citric acid and Na.sub.5DTPA, or a combination of any two or more thereof, where the method further includes centrifuging the mixture to yield a first treated composition, wherein the first treated composition has less total metals and less phosphorus than the composition.

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 methods apparatuses described herein involve recovering of glycol from an aqueous phase to form a stream of recovered glycol and a glycol recovery system. The aqueous phase is fed to the top of a lower theoretical stage in a distillation column. An overhead vapor stream is drawn from the distillation column overhead of an upper theoretical stage, and a bottom stream comprising a stream of regenerated glycol is drawn from the distillation column via a bottom outlet configured below the lower theoretical stage. The stream of recovered glycol comprises the regenerated glycol. In addition, a first middle theoretical stage is situated within the distillation column gravitationally above the lower theoretical stage and below the upper theoretical stage. A side stream of liquid water is drawn from the bottom of the upper theoretical stage in the distillation column.