Anonymous
Dear karthik, we had also faced same problem in our coker history, to avoid choking of SP6 increse the purge steam presurre of SP6 and also keep open the body purge steam R/O bypass valve in onlne drum . because steam goes through R/o is very less and it will lead to coking in sp 6. after done it now a days we dont have any problem with sp6 since long time