Several doubts about the isothermal hydrogen evolution process
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As titled: During the hydrogenation shutdown process, once hot hydrogen contains oil, it enters the constant-temperature dehydrogenation stage. Question 1: To what extent does the temperature drop after hot hydrogen contains oil? (The book is rather vague; it only says to lower the temperature by 20–50°C, but this temperature is still within the range for catalyst hydrogen reduction!) ) 2. To what extent does the reaction system need to be purged with nitrogen before isothermal hydrogen evolution? A specific concentration requirement should be given.
1. Catalyst reduction: monitor hydrogen sulfide in the hydrogen circulation; add sulfur if it is insufficient
2 Use high-purity nitrogen, and then cyclically check whether the hydrogen content in the nitrogen increases. It will take about 3 days
Thank you for your reply. I just don’t quite understand it – does constant-temperature hydrogen evolution take three days?
Generally three days; is your time even shorter?
According to the text in the book, during the stripping stage, hydrogen gas should be circulated at the maximum flow rate, the quench hydrogen should be shut off, and part of the recycled gas with a purity of over 80% should be discharged from the high-pressure separator as needed. During the stripping phase, an appropriate amount of sulfiding agent must be added to maintain the hydrogen sulfide concentration above 0.1%
The reduction temperature for catalysts in the sulfided state is relatively high; it is necessary to consult the catalyst manufacturer for specific details. Our manufacturer specifies 300 degrees