good day
I am plant engineer on ethylene plant and I need your help for decoking procedure.
currently we face a difficulty to reduce Venturi critical pressure after complete decoking pressure CPR. we start decoking activity when cut HC feed and maintained COT at 820 C and dilution steam at 25 t/hr. at this point we introduce the air slowly until COT reached 850c and hold for 1 one hours after that we increase COT to 870 with almost same air flow and waiting for almost 10 hours. co2 concentration only increase at beginning of introducing air and it reached up to 1.5 %. Until end of the procedure, we never notice any change of CO2 concentration.
once complete this procedure, still CPR of several coils on high ration
I need you help if there is some mistake or improvement for this procedure
your help is highly appreciated
thanks