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We are processing HHCGO in our FCCU. My question is that whether we have to process it as combined feed in feed surge drum or we have to process it by injection through individual feed nozzle a higher elevation. Which is the best option and why? And what is the impact on yield pattern?
 
Answers
03/05/2014 A: Arvinder Singh Sahney, Indian Oil Corporation Ltd, sahneyas@yahoo.com
Typicaly HCGO is processed either 'raw' or 'post hydrotreatment' in the FCC unit.
In case it is 'raw' processing, it would be a better idea to inject it in a seperate nozzle at a higher elevation as compared to the feed nozzles.
However, in case of HCGO hydrotreatment (prior to feeding to FCC), it is typical to process a combination of VGO and HCGO in the hydrotreater, in which case HCGO is to be necessarily fed to FCC in admixed condition.
12/04/2014 A: Virendra Kapoor, Petroleum Refining Consultants, vkkapoor9@yahoo.com
Both options are probably possible depending on the percentage of HCGO, suitability of feed nozzle and the desired yield pattern from the unit. Injecting it through nozzle at higher elevation may give an opportunity of Mixed Temperature Control hence higher conversion with greater catalyst to oil ratio management
09/04/2014 A: keith bowers, B and B Consulting, kebowers47@gmail.com
The hydrocracked heavy gas oil will 'over-crack' if admixed with the rest of the feed. Best liquid fuels yields will result from higher up feed injection.
09/04/2014 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
It is typically part of the combined feed. Light feeds, such as naphtha, are fed higher in the riser to increase propylene production. Refinery slop is sometimes fed directly to the riser, although some licensors discourage the technique.