Sulfur transformation in coal during gasification
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According to the book, in the gasification of coal using water-coal slurry, all the sulfur in the coal is converted into crude gas, appearing as H2S and a small amount of COS. I would like to ask everyone whether the non-volatile sulfur in coal also undergoes conversion? What do the actual production data look like?
I only know that the total sulfur content outside is around 0.2% after the transformation; I haven’t conducted any tests to obtain more detailed data
This post was last edited by pyp222 on 2017-5-23 at 14:07. The total amount of sulfur in various forms in coal is referred to as total sulfur. Sulfur in coal usually exists in two forms: organic sulfur and inorganic sulfur. Organic sulfur in coal refers to sulfur that is incorporated into the organic structure of coal; its composition is very complex, with the main forms being thiol, thioether, disulfide, as well as sulfur quinones and thiophenes in heterocyclic forms. Organic sulfur mainly comes from the proteins in coal-forming plants and microbial proteins. The sulfur content in proteins ranges from 0.3% to 2.4%, while the total sulfur content in plants is generally less than 0.5%. Therefore, most coals with a sulfur content of less than 0.5% primarily contain organic sulfur ； Inorganic sulfur in coal mainly comes from various sulfur-containing compounds in minerals. It mainly contains sulfide sulfur and a small amount of sulfate sulfur, with elemental sulfur present occasionally. The sulfur in sulfides is mainly in the form of pyrite, followed by marcasite, magnetite (Fe7S8), sphalerite (ZnS), galena (PbS), etc. During coal gasification, both organic sulfur and sulfide sulfur can enter the gas through combustion; only sulfate sulfur cannot burn and ends up in the coal ash. Therefore, sulfate sulfur is also referred to as fixed sulfur, non-combustible sulfur, or non-volatile sulfur. Organic sulfur and sulfide sulfur are referred to as combustible sulfur; during coal gasification, this portion of sulfur enters the gas mainly in the form of H2S and COS, with H2S accounting for the majority of the total sulfur content in the gas. Since current desulfurization technologies are unable to remove sulfur in the COS form, it is necessary to convert COS into H2S, which can be removed, using sulfur-resistant catalysts in a conversion unit.