A process for the stepwise separation of accompanying gases from a raw synthesis gas stream by a liquid absorbent countercurrently guided through all process steps and circulated via regeneration plants, wherein either the accompanying gases H.sub.2S, COS and CO.sub.2 are separated in a common absorption step or, in one of the selective absorption steps chiefly H.sub.2S and COS are separated and in the next step in flow direction of the gas chiefly CO.sub.2 is separated, and in the last step a separation of accompanying gas residues (fine wash) is effected, wherein before the separation of H.sub.2S and COS an absorption step chiefly for the separation of aromatics and subsequently an absorption step chiefly for the separation of methyl mercaptan is carried out.

The invention relates to a method for removing absorbable gases from pressurized industrial gases contaminated with absorbable gases, without supplying cooling energy. The method includes an industrial gas that is to be purified is purified by an absorbent solvent, the absorbable gases situated therein being removed by the solvent, and the loaded solvent is passed to a stripping stage in which the absorbed gas is desorbed again, and the desorbed gas is compressed, in such a manner that it is heated by the compression, whereupon it is cooled to standard temperature by means of cooling water or cooling air, then expanded, in such a manner that it cools and this cooled desorption gas is again returned to the industrial gas, in such a manner that said industrial gas is also cooled by the admixture.

The system is provided with: a first heat exchanger which is interposed at an intersection between a rich solution supply line and a lean solution supply line, which has absorbed CO.sub.2 and H.sub.2S extracted from a bottom portion of an absorber, and a regenerated absorbent; a second heat exchanger which is interposed at an intersection between a semi-rich solution supply line and a branch line branched at the branch portion C from the lean solution supply line, and the lean solution; a merging portion which merges a branch line configured to supply the lean solution after heat exchange with the lean solution supply line; and a flow rate adjusting valve which is interposed in the lean solution supply line to adjust the distribution amount of the lean solution.

A method of removing oxygenates from a hydrocarbon stream comprises passing a hydrocarbon stream to a caustic tower having a plurality of loops, contacting the hydrocarbon stream with a sulfided catalyst between a first loop of the plurality of loops and a second loop of the plurality of loops to produce a reaction product, passing the reaction product to the second loop, removing at least a portion of the hydrogen sulfide in the second loop of the caustic tower to produce a product stream, and separating the product stream into a plurality of hydrocarbon streams in a separation zone located downstream of the caustic tower. The hydrocarbon stream comprises hydrocarbons, oxygen containing components, and sulfur containing compounds. At least a portion of the sulfur compounds react in the presence of the sulfided catalyst to produce hydrogen sulfide in the reaction product.

The invention generally relates to processes for reducing fouling in amine systems and to equipment useful in such processes. Such amine systems are useful for removing one or more acidic gases such as CO.sub.2 or H.sub.2S from olefin containing hydrocarbon streams. The invention generally relates to minimizing residence time of foulant and foulant precursors at the relatively high temperature found in the amine regenerator and/or to purging the foulant and foulant precursors from the regenerator system. This is accomplished by operating the regenerator column as a stripper (no reflux) and re-routing reflux liquid containing foulant or foulant precursors to a processing location that is less prone to fouling or, optionally, by replacing the reflux liquid with fresh make-up amine or water.

Acid gas compounds are removed from a process gas such as, for example, syngas or natural gas, by flowing a feed gas into a desulfurization unit to remove a substantial fraction of sulfur compounds from the feed gas and flowing the resulting desulfurized gas into a CO.sub.2 removal unit to remove a substantial fraction of CO.sub.2 from the desulfurized gas.

Systems and methods for controlling an amine contactor are provided. An exemplary method includes determining a pickup ratio for a solvent in the contactor, measuring a temperature of a lower tray of the contactor, adjusting the pickup ratio based, at least in part, on the temperature, and adjusting a flow rate for an injection of lean solvent into the contactor based, at least in part, on the pickup ratio.

An absorbing liquid which absorbs the CO.sub.2 or H.sub.2S or both contained in a gas, and which comprises 1) at least one tertiary-monoamine main agent selected from a tertiary-monoamine group and 2) at least one secondary-diamine first additive selected from a secondary-diamine group, the secondary-diamine concentration being within the range of 0.05 to 0.5 in terms of the additive concentration index represented by the following expression (I).

(Additive concentration index)=[(secondary-diamine acid dissociation index) (pKa)/(tertiary-monoamine acid dissociation index) (pKa)](index ratio)×[(secondary-diamine molar concentration) (mol/L)/(tertiary-monoamine molar concentration) (mol/L)](molar ratio)  (I).

This disclosure relates to a process for removing acid gases from a gas stream enriched in acid gases, wherein: (a) the gas stream enriched in acid gases is contacted in an absorption zone with an absorption medium, wherein the absorption medium is an aqueous medium comprising an amine, to form a gas stream depleted in acid gases which comprises an entrained amine and an absorption medium enriched in acid gases; and (b) treating the gas stream depleted in acid gases which comprises an entrained amine in a first scrubbing zone with a first scrubbing medium, wherein the first scrubbing medium is an aqueous medium comprising an amine, the amount of amine comprised by the scrubbing medium being about 0.1 to about 50.0 wt. %, wherein the aqueous medium is saturated with carbon dioxide such that at least 75 wt. % of the amine, based on the total amount of amine comprised by the aqueous medium, is in its carbamate or carbonate form, to form a gas stream depleted in acid gases and in amine and a first scrubbing medium enriched in amine.

A method of removing acid gases from a gaseous stream is provided. The acid gases may include carbon dioxide, hydrogen sulfide and/or sulfur dioxide, by example. Embodiments of the method include mixing an amine-terminated branched polymer solvent with the gaseous stream, resulting in the substantial absorption of at least some of the acid gases. The solvent is an amine-terminated branched PEG, such as by example amine-terminated glycerol ethoxylate, amine-terminated trimethylolpropane ethoxylate, and/or amine-terminated pentaerithritol ethoxylate. Embodiments of the present inventive methods further include regenerating the solvent using electrolysis.