Hydrogen sulfide heavy water production

The most important applications of hydrogen sulfide involve the production of sodium sulfide and other inorganic sulfides. Hydrogen sulfide obtained as a by-product often is converted into sulfuric acid. It also is used in organic synthesis to make thiols or mercaptans. Other applications are in metallurgy for extracting nickel, copper, and cobalt as sulfides from their minerals and in classical qualitative analytical methods for precipitation of many metals (see Reactions). It also is used in producing heavy water for nuclear reactors. 

Commercial-scale processes have been developed for the production of hydrogen sulfide from heavy fuel oils and sulfur as well as from methane, water vapor, and sulfur. The latter process can be carried out in two steps reaction of methane with sulfur to form carbon disulfide and hydrogen sulfide followed by hydrolysis of carbon disulfide (116). 

Hydrogen sulfide is also used in the production of heavy water for the nuclear industry (84). 

Hydrogen sulfide has a variety of industrial uses. Its major use is in the production of elemental sulfur and sulfuric acid. Hydrogen sulfide is also used in the manufacture of sodium sulfide and thiophenes. It is used in metallurgy and in the production of heavy water for the nuclear industry (Beauchamp et al. 1984 HSDB 1998). In the past, hydrogen sulfide was used as an agricultural disinfectant. 

Fig. 26. The production of heavy water is based upon the behavior of deuterium in a mixture of water and hydrogen sulfide. When liquid H2O and gaseous H2S are thoroughly mixed, the deuterium atoms exchange freely between die gas and file liquid. At high temperatures, file deuterium atoms tend to migrate toward file gas, while they concentrate in file liquid at lower temperatures. In the first and second stages of production, file towers of a heavy water plant are operated with the top section cold and file lower section hot. Hydrogen sulfide gas is circulated from bottom to top and water is circulated from top to bottom through the tower. In the cold section, the deuterium atoms move toward file water and are carried downward, while in file hot section, they move toward the gas and are carried upward. The result is that, both gas and liquid are enriched in deuterium at the middle of the tower. A series of perforated trays are used to promote mixing between the gas and water in the towers. A portion of the HjS gas, enriched in deuterium, is removed from file tower at the juncture of file hot and cold sections and is fed to a similar tower for the second stage of enrichment...

Applications Hydrogen sulfide is the starting material for the manufacture of sodium hydrogen sulfide, sodium sulfide and organic sulfur compounds, such as thiophenes or thiols. In several plants hydrogen sulfide is utilized for the production of heavy water. 

All of the previously mentioned plants except those employing distillation of water were parasitic to a synthetic anunonia plant. Their deuterium-production rate is limited by the amount of deuterium in ammonia synthesis gas. To produce heavy water at a sufficient rate, a growing industry of heavy-water reactors requires a deuterium-containing feed available in even greater quantity than ammonia synthesis gas. Of the possible candidates, water, natural gas, and petroleum hydrocarbons, water is the only one for which an economic process has been devised, and the dual-temperature hydrogen sulfide-water exchange process is the most economic of the processes that have been developed. 

Those plants that for primary concentration use water distillation (WD) or the dualtemperature, water-hydrogen sulfide (GS) process are self-contained plants whose sole product is heavy water. 

There have been many assessments and comparisons of heavy-water processes in Canada during the past three decades (15, 31, 32, 33). Despite the wide range of alternatives studied, none that can ofier unlimited production are able to compete with the GS process—deuterium exchange between water and hydrogen sulfide—which was chosen by the US AEG for their large-scale production needs nearly 30 years ago (34). 

Thioacetamide has been used as a substitute for hydrogen sulfide. It is readily obtainable, and the commercial product tested was free of all heavy-metal sulfides except a trace of silver. Thioacetamide is very soluble in alcohol, benzene, or water. The neutral water solution is stable for long periods of time. A slight cloudiness may form in long-stored water solutions but this may be removed by filtration. A solution of thioacetamide can be added directly to solutions so there is no loss of precipitate in hydrogen sulfide delivery tubes. 

Hydrogen sulfide, H2S, is a colourless, poisonous, corrosive, flammable and potentially explosive gas familiar to most people as rotten egg gas Its discovery is credited to Carl Wilhelm Scheele in 1777. The gas is commercially available and applications range from organosulfur and metal-sulfur chemistry to the production of heavy water (Girdler-Spevack process). 

Water pollutant chemicals Dissolved gases in water, rain water, ground water, marine pollution, etc. Carbon monoxide, carbon dioxide, ammonia, inorganic acids, hydrogen sulfide, oxides of sulfur and nitrogen, isocyanides, halogens, isocyanides, arsenides, toxic metals, methane, ethylene, benzene, toluene, xylene, formaldehyde, petroleum products heavy metal and its oxide, etc. 

Hydrogen sulfide is used commercially to purify hydrochloric and sulfiiric acid, to precipitate sulfides of metals, and to manufacture elemental sulfiir and organosulfur compounds. Chemical production processes using hydrogen sulfide include the manufacture of mercaptans pharmaceuticals plastics adhesives television, cathode ray tubes (CRT), and fluorescent tube phosphors dyes pigments biodegradable pesticides ethylene nylon soda ash sodium hydrosulfide heavy water and others. 

Hydrogen sulfide, H2S, is a product of the anoxic decay of organic matter containing sulfur. It is also produced in the anoxic reduction of sulfate by microorganisms (see Chapter 3, Reaction 3.8) and is evolved as a gaseous pollutant from geothermal waters. Wastes from chemical plants, paper mills, textile mills, and tanneries may also contain H2S. Its presence is easily detected by its characteristic rotten-egg odor. In water, H2S is a weak diprotic acid with pA i of 6.99 and of 12.92 S is not present in normal natural waters. The sulfide ion has tremendous affinity for many heavy metals, and heavy metals present in water containing H2S will precipitate as metal sulfides. 

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