Q & A > Question Details
We have a two coke drum DCU. We are facing issue of high Sulphur content in our pet coke. The feed quality has been fairly consistent. Normally we have been operating with a cycle time of 18 hrs & COT of 501 Deg C since last two years. The issue of high sulphur has surfaced over the last two months only. Can anyone suggest the reason?
 
Answers
11/11/2015 A: Sourav Patel, IOCL, souravpatel365@gmail.com
Definitely Sulphur comes from crude type you are processing. Since DCU is designed to process bottom of barrel of crude, the change in feed sulphur content to DCU will help you in analysing high S content in coke. A sulphur balance of your unit will help you to understand the change.
24/08/2015 A: Satyalal Chakravorty, Sr Consultant, satya1354@yahoo.co.in
Feed need to be analysed wrt Sulphur content & CCR vis a vis design. Further please carry out sulphur balance for input streams as well for off gases including H2S content in sour water etc Do you process slop in the coker?
22/08/2015 A: Sridhar Balakrishnan, Bharat Oman Refineries Limited , laksrid@yahoo.com
Crude Oil blend changes can certainly help to an extent. Avoiding asphaltic or highly aromatic crude oil in blend basket , because it contains high asphaltene content, hence more sulphur content. Sulphur species land in bottom of the barrel product.
21/08/2015 A: Ralph Ragsdale, Ragsdale Refining Courses, ralph.ragsdale@att.net
Even if the sulfur content of the crude is constant, the distribution of sulfur in the intermediate streams can change.
20/08/2015 A: Eric Vetters, ProCorr Consulting Services, ewvetters@yahoo.com
Sometimes the feed quality being consistent and feed slate being consistent can be very different. Did you start running a new crude about this time? The total crude sulfur might be the same but different crudes can have widely varying sulfur distributions. My guess is that you have a new crude that has more sulfur distributing to the coker feed than your normal crude slate.