Initial injection amount for catalyst sulfiding?
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For the wet sulfidation of catalysts, DMDS is used as the sulfiding agent. The initial dosage is determined based on the total dosage and the sulfidation time; it is generally around 1.5%. What is the basis for this? Should the initial injection temperature be below 200 degrees Celsius? Is it the liquid sulfiding agent that more easily penetrates the inner surface of the catalyst, or is gaseous hydrogen sulfide more likely to do so? Please have a thorough discussion
The temperature should be kept below 220. The specific parameters depend on the catalyst used, or the catalyst manufacturer will develop a suitable plan
It is all based on the plans provided by the catalyst manufacturers; if there is little sulfur initially but the temperature is high, it can easily lead to the reduction of the catalyst. During operation, we inject DMDS evenly, keeping the temperature rise below 20°C; if the temperature rises, we reduce the amount of DMDS injected. Additionally, if the temperature rise is low and the hydrogen sulfide level in the system is analyzed to be less than 1000 ppm, the injection amount of DMDS will be increased appropriately.
Generally, the reaction temperature is kept below 215°. It is not the sulfiding agent that enters the catalyst, but rather H2S generated by the decomposition of the sulfiding agent that reacts with the catalyst in its oxidized state to form a sulfided form!
Reputable manufacturers usually provide the optimal solution – uniform injection to control temperature rise
How should the DMDS-containing sulfurized oil discharged after introducing fresh feed be treated?
Some of the undecomposed DMDS should decompose as it enters the internal micropores along with the feed, right? ?
Calculate the theoretical amount of vulcanizing agent, and then divide it by the vulcanization time? So what are the differences in vulcanization time for different devices? What is the generally recommended vulcanization time?
The amount of vulcanizing agent to be injected should take into account the amount of catalyst loaded. As for the temperature at which the vulcanizing agent is injected, it is generally between 180 degrees Celsius and 200 degrees Celsius. It’s not absolute. I saw that the temperature for vulcanization is not allowed to exceed 200 degrees Celsius; in other words, under normal circumstances, the temperature at which the vulcanizing agent is introduced is below 200 degrees Celsius.
At 170–190°C, the temperature rise in the reactor for DMDS is quite significant; therefore, it is advisable to start the process at around 150°C
According to foreigners, it’s about checking the amount of circulating hydrogen; it seems to be 50 kg per 10,000 cubic meters