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We are operating HCGO/VGO as feed in Coker hydrotreater unit with system pressure of 95kscg. But actual feed quality is much better than design feed quality.In fact Hydrogen partial pressure is maintained more than design 91 instead of 86 with purity recycle gas as 95%.We thought of optimizing hydrogen consumption as well as power reduction by reducing system pressure . Can anybody tell ,will this attempt help us to bring power in MUG? otherwise how much can I go down further on system pressure ? And I wanted to calculate based on feed spec, how much gas oil ratio is required for my system? Can anyone share calculation basis to arrive gas oil ratio and system pressure to maintain?
 
Answers
20/03/2016 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
Hydrogen to oil ratio or recycle gas to oil ratio is simple to calculate with the knowledge of recycle gas compressor operation curves. Process licensor or any designer can easily help you.
09/01/2016 A: Satish Angadi, Haldor topsoe, satish.angadi@gmail.com
Really interesting question.
Theoretically, Hydrogen partial pressure, at reactor outlet, needs to be maintained, so the pressure can be brought down by 95kscg x (91/96).
Please do simulation and you can see if above calculations matches to it or not.
Before embarking on actual implementation, check MUG/recycle gas performance curves. Will the catalyst licensor allow you?
conversely you can expect longer cycle length by factor of (95/86).
Any update on your analysis will be good.
12/12/2015 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
This is an interesting study, and fun to do. You need the set of curves that correlates the variables. If you have access to the process licensor, he can furnish you those curves. The correlation is useful for debottlenecking studies as well.