An overview of the development of chemical desulfurization technology for organic sulfur coal

Coal is a highly valuable energy source. It is used to generate electricity in power plants and is one of the most cost-effective fuels, becoming less expensive than natural gas and crude oil. Sulfur oxide is produced when high-sulfur coal is burned and reacts with water and oxygen to cause acid rain and pollution. Various chemical coal desulfurization techniques currently remove only inorganic sulfur, such as pyrite and sulfur ether, whereas organic sulfur, such as thiophene, is harder to remove. Organic sulfur is covalently bound to coal's macromolecular backbone, and the C-S bond must be broken to remove the sulfur efficiently. Coal's complex molecular structure and properties would be lost throughout this process. Chemical desulfurization was the most effective method of removing inorganic and organic sulfur. This method overcomes the limitations of conventional physical desulfurization, which primarily removes inorganic sulfur and can be lengthy in some cases. This article covered the development of chemical desulfurization technologies for organic sulfur coal, including acid and alkaline leaching, peroxyacetic acid oxidation, electrochemical or electrolysis desulfurization, microwave irradiation, and ultrasonic-assisted extraction.