A process for treating an H.sub.2S- and CO.sub.2-comprising fluid stream, in which a) the fluid stream is treated in a first absorber at a pressure of 10 to 150 bar with a first substream of a regenerated H.sub.2S-selective absorbent to obtain a treated fluid stream and an H.sub.2S-laden absorbent; b) the H.sub.2S-laden absorbent is heated by indirect heat exchange with regenerated H.sub.2S-selective absorbent; c) the heated H.sub.2S-laden absorbent is decompressed to a pressure of 1.2 to 10 bar in a low-pressure decompression vessel to obtain a first CO.sub.2-rich offgas and a partly regenerated absorbent; d) the partly regenerated absorbent is regenerated in a desorption column to obtain an H.sub.2S-rich offgas and regenerated absorbent; e) the H.sub.2S-rich offgas is fed to a Claus unit and the offgas from the Claus unit is fed to a hydrogenation unit to obtain hydrogenated Claus tail gas; f) the hydrogenated Claus tail gas and the first CO.sub.2-rich offgas are treated in a second absorber at a pressure of 1 to 4 bar with a second substream of the regenerated H.sub.2S-selective absorbent to obtain a second CO.sub.2-rich offgas and a second H.sub.2S-laden absorbent; and g) the second H.sub.2S-laden absorbent is guided into the first absorber. Also described is a plant suitable for performance of the process. The process is notable for a low energy requirement.

A process and system for treating a hydroprocessing unit effluent gas stream for recycling includes introducing the effluent gas stream into a hydrogen purification zone and recovering a hydrogen-rich gas stream and a liquid stream containing a mixture that includes C1 to C4 hydrocarbons and H.sub.2S which is then mixed with an oxidant and fed to an oxidation unit containing catalyst for conversion of the H.sub.2S to elemental sulfur vapors that is separated for recovery of the elemental sulfur, and recovering a sweetened mixture that includes C1 to C4 hydrocarbons. Alternatively, the hydroprocessing unit effluent gas stream containing H.sub.2S is cooled, contacted with a solvent to absorb the C1 to C4 hydrocarbons and H.sub.2S, with the hydrogen-rich stream being recovered for recycling to the hydroprocessing unit, and the rich liquid solvent being flashed to produce a lean solvent stream for recycling to the adsorption zone and a mixed gas stream that includes the C1 to C4 hydrocarbons and H.sub.2S that is passed to an oxidation zone and is reacted with an oxidant in the presence of a catalyst to complete the process as described above for the recovery of elemental sulfur and a mixture that includes the sweetened C1 to C4 hydrocarbons.

It is an object of the present invention to downsize facility for removing or reducing concentration of hydrogen sulfide and oxygen in gas and reduce facility cost. Syngas g contains hydrogen sulfide and oxygen as target constituents of removal or reduction in concentration. Hydrogen sulfide content and oxygen content in the syngas g are measured in a preceding measurement part 13. Then, the syngas g is contacted with desulfurizing agent 14a including iron oxide. Selection is made whether to further execute deoxidization in a deoxidizing part 16 or omit or simplify the deoxidization according to results of measurements in the preceding measurement part 13.

Recovering helium from a gaseous stream includes contacting an acid gas removal membrane with a gaseous stream to yield a permeate stream and a residual stream, removing a majority of the acid gas from the residual stream to yield a first acid gas stream and a helium depleted clean gas stream, removing a majority of the acid gas from the permeate stream to yield a second acid gas stream and a helium rich stream, and removing helium from the helium rich stream to yield a helium product stream and a helium depleted stream. A helium removal system for removing helium from a gaseous stream including hydrocarbon gas, acid gas, and helium includes a first processing zone including a first acid gas removal unit, a second processing zone including a second acid gas removal unit, a third processing zone, and a helium purification unit.

Provided is a wet desulfurization process using a suspension bed. The process comprises mixing desulfurization slurry with a hydrogen sulfide containing gas to obtain a first mixture, and passing the first mixture into a suspension bed reactor from bottom to top, with controlling the first mixture to have a dwell time of 5-60 minutes in the reactor to allow they contact and react sufficiently with each other; and subjecting a second mixture obtained from the reaction to gas liquid separation to produce a purified gas. The process of the present invention may reduce the hydrogen sulfide content in the hydrogen sulfide containing gas from 2.4-140 g/Nm.sup.3 to 50 ppm or less, so that the desulfurization efficiency is 98% or more. The process of the present invention is simple and reasonable, with high desulfurization and regeneration efficiency, simple equipment, little occupation of land and low investment, which is very suitable for industrial promotion.

A process for treating an H.sub.2S- and CO.sub.2-comprising fluid stream, in which a) the fluid stream is treated in a first absorber at a pressure of 10 to 150 bar with a first substream of a regenerated H.sub.2S-selective absorbent to obtain a treated fluid stream and an H.sub.2S-laden absorbent; b) the H.sub.2S-laden absorbent is heated by indirect heat exchange with regenerated H.sub.2S-selective absorbent; c) the heated HS-laden absorbent is decompressed to a pressure of 1.2 to 10 bar in a low-pressure decompression vessel to obtain a first CO.sub.2-rich offgas and a partly regenerated absorbent; d) the partly regenerated absorbent is regenerated in a desorption column to obtain an H.sub.2S-rich offgas and regenerated absorbent; e) the H.sub.2S-rich offgas is fed to a Claus unit and the offgas from the Claus unit is fed to a hydrogenation unit to obtain hydrogenated Claus tail gas; f) the hydrogenated Claus tail gas and the first CO.sub.2-rich offgas are treated in a second absorber at a pressure of 1 to 4 bar with a second substream of the regenerated H.sub.2S-selective absorbent to obtain a second CO.sub.2-rich offgas and a second H.sub.2S-laden absorbent; and g) the second H.sub.2S-laden absorbent is guided into the first absorber. Also described is a plant suitable for performance of the process. The process is notable for a low energy requirement.

The present invention relates to a method and a system for catalytic oxidation of a lean H.sub.2S stream. More specifically, the invention concerns a novel way of removing sulfur dioxide (SO.sub.2) formed by catalytic oxidation of hydrogen sulfide (H.sub.2S) with the purpose of removing H.sub.2S from a gas. This catalytic oxidation of H.sub.2S yields sulfur dioxide (SO.sub.2) through the use of known catalysts, so-called SMC catalysts.

A combustible gas from carbon black production is utilized in a gas engine by adding an oxygen-containing gas to the combustible gas, passing said mixed gas over a selective catalyst, which is active for oxidizing H.sub.2S to SO.sub.2 but substantially inactive for oxidation of CO, H.sub.2 and other hydrocarbons with less than 4 C-atoms, passing the converted gas through an SO.sub.2 removal step, and passing the cleaned gas to a gas engine or to an energy recovery boiler. This way, the tail gas from carbon black production, which is normally combusted in a CO boiler or incinerated, can be utilized to good effect.

Installation and method for treating a flow comprising hydrogen sulfide The invention relates to an installation and a method for treating hydrogen sulphide. In particular, the invention relates to an installation and a method comprising at least one system for oxidizing hydrogen sulfide to sulfur (S) and water (H.sub.2O) with a solid reagent and at least one oxidizing system with an agent for oxidizing the solid reagent present in the reduced state, wherein the system of oxidizing the hydrogen sulfide to sulfur and the system for oxidizing the solid reagent, are so arranged that the hydrogen sulfide is not brought into contact with the agent oxidizing the solid reagent.

A two or particularly three-phase process, and corresponding apparatus, desulfurizes sour hydrocarbon gas, e.g., natural gas, generally better than known, using a fixed-bed, two-phase processes in terms of the amount of H.sub.2S scavenged and the breakthrough time of H.sub.2S. The three-phase process is effective in scavenging H.sub.2S at ambient temperature and pressure, using a copper salt catalyst impregnated on alumina or other generally inert support, which is regenerable.