We need some info about drying of hydrocracker catalyst by long period recycle gas circulation in case of start up and shut down of hydrocracker unit and problems caused by this phenomenon. Can anybody help us? Is it very harmful for catalysts?
Answers
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07/10/2008
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A:
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Samuel Sinanan, IPSL, Samuel.Sinanan@ipsl.co.tt
IF your catalyst is a NiMo or CoMo catalyst there is a rule that once the catalyst is a high temperatures (>475 deg F), in the presence of hydrogen and there is less than 1000 ppm of H2S in the recycle gas, there can be permanent deactivation of the catalyst. In these instances the sulphur is stripped out of the catalyst. Catalyst dryout is only required after the unit is started after catalyst loading. If presulphided catalysts are utilised catalyst dryout is not recommended.
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