In our plant, we have 7 heaters for Distillation unit, NHT and CRU unit. Fuel Gas that is generating from CRU Unit (80% H2) is being used for all those heaters. But, gum or glue is observed at the pressure regulating system which is situated on fuel gas line which mean it is depositing at the reduced area due to restricted flow path. My question is that if the olefin/unsaturated compound present in the desulfurized naphtha ( CRU Feed), is it getting Oxygen from Oxygenated compound like MTBE, TAME or Methanol and so on to form gum or is it getting O2 from the existing system? If this is not the case then what could be the reason of forming gum in the fuel gas?