Pre-sulfurization of hydrogenation catalyst in SCOT unit
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Hey everyone, does anyone have any information related to pre-sulfidization with acidic gases? The catalysts used here are TG107 from Axens and TGS-02 from Porocel; both of them belong to the category of low-temperature catalysts. Before pre-sulfidization, the hydrogen concentration in the gas generator was 3%, after which acidic gas (H2S) was introduced for pre-sulfidization. The temperature was gradually increased; hydrogen was consumed rapidly, and it was almost completely used up after 4 hours. However, the temperature at the bottom of the reactor still did not reach its maximum value, resulting in incomplete pre-sulfidization. Pre-sulfidization continued with hydrogen production. The acid gas concentration cannot be maintained at 1%; estimation is the only option available. Due to the impact of plant startup, the pre-sulfurization of the acid gas is incomplete. After the gas enters the system, a Claus three-stage sulfur cooling process is used for pre-sulfurization of the gas, but overheating occurs at the bottom, reaching 340°C. How long does pre-sulfurization of acid gas usually take? What is the basis for determining when pre-vulcanization is complete (in the absence of sampling at the reactor inlet and outlet for analysis – it’s a rather odd approach here, as neither the process gas nor the acid gas is analyzed)? And the temperature rise distribution phase during pre-vulcanization? The hydrogen consumption in the gas generator cannot keep up with the amount of sour gas fed in; when the hydrogen level here drops, the supply of sour gas is stopped. Why is then the hydrogen consumption so high?
The sulfidation process requires a large amount of hydrogen; when too much acidic gas is introduced, more hydrogen is consumed. There is a certain ratio required between acidic gas and hydrogen, and this depends on the requirements of various catalyst manufacturers or on the on-site sulfidation experience of their technicians. These two foreign catalysts are almost being replaced by domestic ones.
The situation is rather special; I’ve been using foreign products all along, and I switched to a domestic one once, but the performance was poor
What is the highest temperature reached during vulcanization? The maximum temperature requirement has not been met; what is the temperature during actual operation, and is it too high?
Reduce the air supply to the sulfur production furnace, increase the hydrogen sulfide content in the acidic gas, lower the sulfur dioxide level, and the hydrogen content will decrease as well. The amount of hydrogen is not simply the amount added; a large portion of it comes from the hydrogen generated by the side reactions that occur earlier.
Reduce the air supply to the sulfur production furnace, increase the hydrogen sulfide content in the acidic gas, lower the sulfur dioxide level, and the hydrogen content will decrease as well. The amount of hydrogen is not simply the amount added; a large portion of it comes from the hydrogen generated by the side reactions that occur earlier.
During the vulcanization process, the maximum temperature reaches 260–270; after the gas is introduced during the cutting process, the peak temperature rises to 310. Once vulcanization is complete, the material is pre-vulcanized once more using the process gas
How are Porocel catalysts? They aren’t widely used in China
If the presulfiding effect is good, the reaction is relatively mild, with modest temperature increases at the inlet and outlet, resulting in overall stability.
What is the inlet temperature? Is it a low-temperature catalyst? Currently, in China for SCOT applications, domestic agents are mostly used; imported agents are likely to be more expensive.
The inlet temperature during operation is around 235, while the outlet temperature is between 250 and 260