• We frequently face the failure of the copper corrosion test of LPG from CCR Platforming Unit. 0.5 wt. ppm sulfur is maintained in the platforming unit feed by injection of DMDS. Kindly suggest operational response to address the problem.



  • Nagarathinam S Murthy, McKinsey & Company, Chennai, nssvdvr@gmail.com

    We faced similar problem at a refinery in India way back in 2000. All that we did, then was to drive out C2 (ethane) from LPG ex CCR as any presence of C2 in LPG (which is typically a mixture of C3 and C4s ex CCR). Further, the LPG from CCR with traces (~ 1 to 2ppm) of RSH can not protect failure of Cu strip by H2S even though present in LPG ex platformer less than < 0.5ppm. Another viable solution is to go for a new scrubber for CCR LPG with say 10% caustic. Good luck.




    Check for critical sulphur types that can get escaped during hydrotreating. Check for chloride species in LPG. Chlorides can also cause failures of copper strip corrosion of LPG product.



  • Marcio Wagner da Silva, Petrobras, marciows@petrobras.com.br

    Normally, the LPG production in catalytic reforming units are low and investment in a dedicated LPG treating section is not economically attractive. Considering that the DMDS injection is applied to minimize the coke deposition over the catalyst and this is already optimized, my suggestion is to study to send the LPG stream from your catalytic reforming unit to be treated in another LPG producer in the refinery like FCC or delayed coking units which normally relies on high flowrate LPG treating sections and can absorb and treat the LPG from catalytic reformer.