How to use the vulcanizing agent DMDS

Due to production and safety requirements, catalysts are in an oxidized state at the time of leaving the factory. Before use, they must undergo presulfurization to convert the oxidized catalyst into a stable sulfided state, thereby enhancing the catalyst’s activity and stability and extending its lifespan. Dimethyldisulfide is commonly used as a vulcanizing agent; some refineries also use hydrogen sulfide produced on-site. The pre-sulfurization of catalysts is generally carried out inside the reactor; abroad, there are also techniques for pre-sulfurization outside the reactor. Inside-the-reactor catalyst pre-sulfurization can be further divided into two types: wet pre-sulfurization, which uses sulfurized oil as the sulfurizing agent carrier, and dry pre-sulfurization, which uses recycled hydrogen as the sulfurizing agent carrier. During the pre-sulfurization of the catalyst, due to its inherent activity, excessive temperature rise may occur in case of an emergency if temperature control is inadequate. Furthermore, at higher temperatures and during the early stages of presulfiding when the hydrogen sulfide level in the system is low, the oxidized metal components on the catalyst can be reduced to metal by hydrogen, resulting in catalyst deactivation. Therefore, during the pre-sulfidization of the catalyst, it is necessary to strictly adhere to the relevant temperature specifications and continuously monitor the temperature of the catalyst bed to prevent excessive temperature rises. This post was last edited by han9th on 2008-3-9 21:24]