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While processing heavier and cracked feeds in Diesel Desulfurisation units the decativation could not take place due to metals poisoning or coke deposition. What are the views on predominant factor? If it is because of coke, is the only solution to make the feed lighter and process less of cracked stuff? However, if poisoning is due to metals, could a small bed of demet catalyst in the first bed prolong the life of the catalyst?
 
Answers
06/03/2008 A: Mukesh Patel, Reliance Industries Limited, mukesh.patel@ril.com
Monitoring of feed quality (e.g metals content, Condarson Carbon Residue etc) will help in knowing the type of feed contaminants which are responsible for deactivation. Most of the time, there will not be only one reason / contaminant which deactivate the catalyst. It is cumulative effect. This can be overcome by selecting proper demet catalyst.
03/03/2008 A: keith bowers, B and B Consulting, kebowers47@gmail.com
You should discuss this issue with your catalyst vendor. New generation catalysts can be tailored for maximum life for your specific feedstock. Catalysts can maintain full activity with over 50% weight added 'metals'. Sometimes this requires a bed of 'demet' catalyst.