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What is the typical Distillation D-86 we maintain for LCGO and HCGO streams in Delayed Coker unit?
When trying to maintain the D-86 Distillation for LCGO heavier what are the specific issues we can face in Coker fractionator? We want to achieve D-86 T95 at 385 deg C, is it possible or we can face issues related to mis-operation or coking in the column?

Additional info:
Our worry is related to initiation of coking for HCGO stream if we try to cut the LCGO heavy up-to 380 deg C or 385 deg C. As per typical guideline of Licensor, 370 deg C should be the end -point of LCGO stream.
 
Answers
01/06/2016 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
You can optimize the cut between light and heavy gas oil in the usual manner, i.e., identify the objectives, simulate the column operation in a case by case manner and compare the key results with equipment capacities. Product qualities such as con carbon and metals will not be included in the simulations. Increasing the end point of the LCGO would directionally increase metals and concarbon content of the LCGO, but not significantly. Metals contents of the HCGO are important, however, so the final selected distillation scheme should include adequate liquid flow in the wash oil section. Changing the fractionation should not increase coke buildup in the bottom of the column.
01/06/2016 A: Sridhar Balakrishnan, Bharat Oman Refineries Limited , laksrid@yahoo.com
Typical range ASTM Distillation for LCGO are 170 to 380 deg.C , Distillation cut for HCGO is between 280 to 590 Deg.C .