Reduction temperature of diesel hydrogenation catalyst (sulfided state)
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During normal diesel hydrogenation operations, can catalyst reduction occur in the reaction system when the hydrogen sulfide level is at 0? What is the reduction temperature? No theoretical data needed; please reply with practical experience from hands-on work. Thank you
Before the device is put into operation, the patent association specifies the operating temperature and limits. Each device uses a different catalyst and operates at a different temperature ； The reduction temperature also varies depending on whether it is the first time using a new catalyst or an existing, used catalyst; specific requirements should be referred to those provided by the patent holder. I think there are few cases of dry reduction of catalysts, so it’s quite difficult to find practical experience in this area.
The catalyst varies, and so does the reduction temperature; refer to the solution provided by the catalyst manufacturer!
We use 160 as the feed value, then adjust the temperature to increase it; nothing bad has happened, and in fact the value can be a bit higher
The catalysts we use are mainly Yabao and Axens. During startup, when hydrogen is circulated to raise the temperature, it is strictly prohibited to exceed 160°C; once this temperature is reached, the feed pump must be started to introduce oil in order to establish a circulation between the light and heavy fractions before further temperature increase is allowed； Shutting down is also required to ensure that the highest point of the reactor bed does not exceed 160 before the hydrogen feed pump can be started. If the circulating hydrogen is at 0, the catalyst becomes almost completely deactivated within 2 hours.
In the normal production process of diesel hydrogenation, it is impossible for the hydrogen sulfide level in the reaction system to be 0; under normal operating conditions, the hydrogen sulfide content in the system can never reach 0. Generally, its level is below 300 PPM, and when the temperature is above 260 degrees, a reduction reaction is likely to occur