The invention relates to a process for removal of unwanted, in particular acidic gas constituents, for example carbon dioxide and hydrogen sulfide, from a crude synthesis gas by gas scrubbing with a scrubbing medium. According to the invention the flash gases obtained during the decompression of the laden scrubbing medium are supplied to a recompressor in order to recycle these to the crude synthesis gas and thus utilize them materially after the recompression. Alternatively or in addition the flash gases may also be supplied to a decompression turbine to recover refrigeration and mechanical work. If the recompressor and/or the decompression turbine are/is designed to have multiple stages, the flash gases obtained at different pressure levels are preferably supplied to a corresponding pressure level of the recompressor and/or of the decompression turbine.

The invention relates to a process for removal of unwanted, in particular acidic, gas constituents, for example carbon dioxide and hydrogen sulfide, from a crude synthesis gas containing metal carbonyls by gas scrubbing with a scrubbing medium. According to the invention water is added directly into the feed conduit of the methanol water mixture containing metal sulfides before the introduction thereof into the methanol-water separating column and/or water is injected directly into the methanol-water separating column at at least one point. This avoids deposits or encrustations of metal sulfide particles in the methanol-water separating column.

An absorption column including at least one external heat exchange circuit for cooling or heating the absorption liquid, including one or more serially connected heat exchangers, wherein the junction of the pipeline for withdrawal of the absorption liquid from the column is disposed above the junction of the pipeline into the first heat exchanger in the flow direction, wherein the pipeline also includes a dumped bed

The invention relates to a process for regenerating a laden scrubbing medium from a gas scrubbing for purifying raw synthesis gas in which the laden scrubbing medium is at least partially freed of bound gas constituents in a regeneration stage to obtain a regenerated scrubbing medium. According to the invention it is provided that after withdrawal from the regeneration stage the regenerated scrubbing medium is supplied to an intermediate vessel and the regenerated scrubbing medium is withdrawn from the intermediate vessel and supplied to an absorption apparatus for purifying raw synthesis gas. The invention further relates to an apparatus for performing the process according to the invention comprising a regeneration apparatus in which bound gas constituents are removable from a laden scrubbing medium, wherein according to the invention it is provided that the apparatus comprises an intermediate vessel into which a regenerated scrubbing medium producible in the regeneration apparatus is transferable and in which the regenerated scrubbing medium is storable.

Disclosed are methods useful in applications relating to blast furnace processes. The methods of the present invention provide enhanced deposition inhibition of particulate matter in top-pressure recovery turbines. The methods of the present invention comprise adding nitrogen-containing compounds to a top-pressure recovery turbine, inhibiting deposition of solids formed from blast furnace gas on top-pressure recovery turbine components.

The present invention relates to an absorbent, an absorbent system and a process for removing acidic gas such as CO.sub.2 from exhaust gases from fossil fuel fired power stations, from natural gas streams, from blast furnace oven off-gases in iron/steel plants, from cement plant exhaust gas and from reformer gases containing CO.sub.2 in mixtures with H.sub.2S and COS. The liquid absorbent, a mixture of amine and amino acid salt is contacted with a CO.sub.2 containing gas in an absorber and CO.sub.2 in the gas stream is absorbed into the liquid. The absorbed CO.sub.2 forms more than one type of solid precipitate in the liquid at different absorption stages. In a first absorption stage solid precipitate of amine bicarbonate is formed and is withdrawn as slurry from the bottom of a first absorber section. In a second absorption stage solid precipitate of alkali metal bicarbonate is formed and withdrawn as slurry at the bottom of a second absorber section. The slurry withdrawn from the first absorption section is heated to dissolve the precipitate with CO.sub.2 release in an amine flash regeneration tank. The slurry from the second precipitation stage is withdrawn from the bottom of the second absorber section and sent to a regenerator for desorption with CO.sub.2 release. The lean amine and amino acid salt mixture from the flash regenerator and desorber are mixed and returned to the top of the absorber. This absorbent system improves carbon dioxide removal efficiency due to its higher CO.sub.2 removal ability per cycle when compared with conventional amine, absorbent from organic acid neutralized with inorganic base and carbonate based absorbent system. It exhibits less solvent vaporization loss because part of the absorbent is in salt form.

Systems, apparatuses and methods of utilizing a Fischer-Tropsch (FT) tail gas purge stream for recycling are disclosed. One or more methods include removing an FT tail gas purge stream from an FT tail gas produced by an FT reactor, treating the FT tail gas purge stream with steam in a water gas shift (WGS) reactor, having a WGS catalyst, to produce a shifted FT purge stream including carbon dioxide and hydrogen, and removing at least a portion of the carbon dioxide from the shifted FT purge stream, producing a carbon dioxide stream and a treated purge stream. Other embodiments are also disclosed.

The invention relates to novel nitrogen compounds belonging to the family of tertiary diamines of general formula (I) below, wherein R is an alkanediyl radical (CH.sub.2)n- with n=2, 3, 4, 5 or 6. ##STR00001##
The compound according to the invention is for example N,N,N,N-(tetramethyl)-1,6-diamino-2,5-hexanediol or N,N,N,N-(tetramethyl)-1,8-diamino-2,7-octanediol. The invention also relates to the method for preparing them and to their use for removing acid compounds contained in a gaseous effluent.

The present invention relates to an aqueous alkanolamine solution demonstrating low volatility comprising 2-di-methylamino-2-hydroxymethyl-1, 3-propanediol useful for removing acid gases from gaseous mixtures. Said aqueous alkanolamine solution may further comprise one or more of an acid or acid-forming compound, another amino compound, an activator, a physical solvent, or one or more other compounds used in gal-liquid treatment practices. Further, the present invention relates to a process for removing acid gases from a gaseous mixture, preferably hydrogen sulfide, comprising the step of contacting the gaseous mixture with said aqueous alkanolamine solution. Examples of the gaseous mixtures include natural gas, synthesis gas, tail gas, and refinery gas.

Systems, apparatuses and methods of utilizing a Fischer-Tropsch (FT) tail gas purge stream for recycling are disclosed. One or more methods include removing an FT tail gas purge stream from an FT tail gas produced by an FT reactor, treating the FT tail gas purge stream with steam in a water gas shift (WGS) reactor, having a WGS catalyst, to produce a shifted FT purge stream including carbon dioxide and hydrogen, and removing at least a portion of the carbon dioxide from the shifted FT purge stream, producing a carbon dioxide stream and a treated purge stream. Other embodiments are also disclosed.