Conversion hydrogen sulfide

By-product processing Hydrogen sulfide Conversion to elemental sulfur or sulfuric acid by liquid absorption, wet oxidation to elemental sulfur, combustion to SO2... 

B. Gas purification (removal of water, dust, and hydrogen sulfide, conversion of organic sulfur in the presence of highly alkalized iron catalysts). 

Hydrogen sulfide conversions of up to 62 mL min i were obtained at 900 °C with a 40% H2S stream flowing at 200 mL mimL This corresponded to an equivalent current density of 710 mA cm and close to 550% removal beyond that expected from thermodynamic hydrogen sulfide thermal decomposition at this... 

Kahna DW, Mass ET Jr (1985) Indirect hydrogen sulfide conversion-I. An acidic electrochemical process. Int J Hydrogen Energy 10(3) 157-162... 

The conversion products, other than gas and hydrogen sulfide (H2S), are essentially a gasoline fraction that, after pretreatment, will be converted by catalytic reforming an average quality distillate fraction to be sent to the gas oil pool and an atmospheric residue or vacuum distillate and vacuum residue whose properties and impurity levels (S, N, Conr. 

Gaseous Effluents. Twenty percent of the carbon disulfide used in xanthation is converted into hydrogen sulfide (or equivalents) by the regeneration reactions. Ninety to 95% of this hydrogen sulfide is recoverable by scmbbers that yield sodium hydrogen sulfide for the tanning or pulp industries, or for conversion back to sulfur. Up to 60% of the carbon disulfide is recyclable by condensation from rich streams, but costly carbon-bed... 

Conversion of carbon in the coal to gas is very high. With low rank coal, such as lignite and subbituminous coal, conversion may border on 100%, and for highly volatile A coals, it is on the order of 90—95%. Unconverted carbon appears mainly in the overhead material. Sulfur removal is faciUtated in the process because typically 90% of it appears in the gas as hydrogen sulfide, H2S, and 10% as carbonyl sulfide, COS carbon disulfide, CS2, and/or methyl thiol, CH SH, are not usually formed. 

In this process, any sulfur present in the coal exits the gasifier as hydrogen sulfide which is removed by various processes such as a Hohnes-Stretford unit where the sulfide is absorbed and regenerated. The resulting sulfur is filtered out as a cake (39 wt %) which is sold as a valuable feedstock (see Coal CONVERSION PROCESSES, GASIFICATION SULFURREMOVAL AND RECOVERY). 

Alternative means for removal of carbonyl sulfide for gas streams iavolve hydrogenation. For example, the Beavon process for removal of sulfur compounds remaining ia Claus unit tail gases iavolves hydrolysis and hydrogenation over cobalt molybdate catalyst resulting ia the conversion of carbonyl sulfide, carbon disulfide, and other sulfur compounds to hydrogen sulfide (25). 

Conversion Processes. Most of the adsorption and absorption processes remove hydrogen sulfide from sour gas streams thus producing both a sweetened product stream and an enriched hydrogen sulfide stream. In addition to the hydrogen sulfide, this latter stream can contain other co-absorbed species, potentially including carbon dioxide, hydrocarbons, and other sulfur compounds. Conversion processes treat the hydrogen sulfide stream to recover the sulfur as a salable product. 

As worldwide attention has been focused on the dangers of acid rain, the demand to reduce sulfur dioxide [7446-09-5] emissions has risen. Several processes have been developed to remove and recover sulfur dioxide. Sulfur can be recovered from sulfur dioxide as Hquid sulfur dioxide, sulfuric acid, or elemental sulfur. As for the case of hydrogen sulfide, sulfur dioxide removal processes are categorized as adsorption, absorption, or conversion processes. 

Disposal of the spent caustic solution can be a troublesome environmental problem. Depending on the plant location, acid gases are either sent to a fired heater or treated in a Claus unit for conversion of hydrogen sulfide to elemental sulfur. 

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