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What are the consequences of too low hydrogen sulfide levels after diesel hydrodesulfurization? The lean liquid is not being used; the hydrogen sulfide level after desulfurization is 400. What are the effects of this? I seek advice from experts
A low hydrogen sulfide content in the recycled hydrogen may have an impact on the catalyst, especially when the nitrogen content is high.
Since the lean liquid was not used, the hydrogen sulfide content in the circulating gas remained at 400 PPm, which had no impact on the reaction process. However, given that this level remains low over an extended period, it is necessary to consult the catalyst manufacturer to determine whether this could affect the catalyst.
I don’t understand; isn’t it true that the lower the hydrogen sulfide content in the cycle, the better? Is it true that the higher, the better?
400 ppm in the recycled hydrogen is not considered low; it is necessary to ask the catalyst manufacturer what the lowest possible level is. It is said that if it is high-sulfur oil, it’s okay if the hydrogen sulfide content is a bit low
400 should work. The required range for hydrogenation catalysts is 300 to 1000; the main concern is that hydrogen at temperatures above 200 degrees can reduce the sulfided catalysts to lower-valent metals or elemental metals, thereby reducing their activity. Too low a level of hydrogen sulfide can disrupt this balance. There are also those who believe that if high-sulfur raw materials are processed, it is fine as long as there is no hydrogen sulfide after desulfurization.
The temperature tolerance of hydrogen-sulfur-free catalysts varies from manufacturer to manufacturer; this specific temperature needs to be confirmed with the manufacturer. Does the sulfur content in the circulating hydrogen remain consistently at 400 ppm when the desulfurization system is not in operation?
The impact is minimal; if the H2S concentration is low, reaction to produce H2S begins as soon as it enters the top of the reactor.
Our standard specifies a level of not less than 500 ppm, but under normal production conditions there is no problem, as long as the supply of raw materials is uninterrupted, the sulfur content in the reactor will not drop too low; the main concern is hydrogen reduction of the catalyst.
As long as the catalyst is not reduced, the problem won’t be serious.