1 reply to this topic

[paidis]

hi everybody

we check our unit and find hydrocarbone in flue gas of our reboiler and we think some coils of convection section has hole . ( we dont know how many holes and where there are. ) at now we ready snuffing steam for this heater for shut down time . is any producere for this situation for emergency and normal shut down .
what we must do for safty in start up and shut down until we repair it ?

reboiler has radiation section and 3 convection section . middile convection section has this problem and our fluid in this section is C8 aromatic .

thanks

[USR]

paidis:
I think you must immediately take your unit shutdown and get the coils replaced.Your oxygen analyzer and hydrocarbon analyzer must have given you enough indication about the leakage in the tubes.In my case we had leakage in the radiation coils of the furnace which gives preheat to the combined feed(hydrocarbon+hydrogen) before it enters the hydrotreater reactor.The reactor operates at an inlet pressure of 22kg/cm2 this inlet pressure started dropping because of the leakage in the tubes.We had dense smoke coming out of the stack.We tripped our recycle gas compressor.Cut off fuel gas supply to the furnace and stop the feed pump.The snuffing steam to the furnace was then lined up and the damper was kept 100% open.We also had water curtain for our furnace hope you have that installed too.After ensuring all this we finally depressurised our reactor circuit to the flare.Our recycle gas compressor has a N2 line on the discharge side of the compressor.After complete depressurisation and ensuring that the pressure is less than the N2 header pressure(5kg/cm2) N2 was lined up.Hope this experience helps.