1.Whether DMDS injection is keeping continuously at platformer feed by refiners ? 2.Control at stripper bottom sulphur by NHT operation to maintain recycle gas H2S at platformer ;Is it acceptable ?
Subramoni Iyer M.R., CGM (Tech.), BPCL-Kochi(Expert) - 13-Mar,2019 07:40
1. DMDS is continuously injected into the platforming section to avoid Metal catalyzed coking (MCC). 1-2 ppm of H2S in RG will prevent MCC formation. 2. Desulphurisation is the easy reaction and denitrificatiion is difficult reaction. By reducing reactor temperature to slip Sulphur will lead to slippage of nitrogen.
Jayesh Patel, CTSM, IOCL-Mathura(Expert) - 15-Mar,2019 14:54
I am agreed to sir Recycle gas should have 1-2 ppm H2S to avoid MCC. In my view:- CCRU feed sulfur ends up in recycle gas as H2S. As per thumb rule, Recycle gas H2S will be 3-4 times of feed sulfur. So, If feed having 0.3 ppm sulfur, RG H2S will be 1-1.2 ppm. But by injecting DMDS in feed, Reformer tubes will be passivated (As DMDS shall decompose at 230 o C and H2S is liberated) , this is required to avoid scale formation. So, DMDS injection is preferred over increase in NHT stripper bottom sulfur. Nitrogen ends up as ammonium chloride and it is being precipitated at 55 o C (Mainly in RGC suction circuit.
(2) Comments