Furnace tube treatment. Dimethyl Sulfide (DMS) is used to prevent the build-up of coke deposits in furnaces used to manufacture directly reduced iron (DRI). Coke formation is a persistent problem in direct iron ore reduction. Coke can decrease the gas flow as it accumulates in furnace tubes. It also acts as an insulator in the tube, requiring higher heat input to maintain furnace performance. DMS can be used as an additive in the gas feed to inhibit the formation of coke in the furnace tube and minimize these issues.
Additionally, coke build-up leads to carburization, which involves the diffusion of carbon into the metal of the furnace. This leads to premature failure of the furnace tube, and an associated maintenance/repair expense.