In the operation of delayed coking unit, the flow fluctuation of radiation feed pump is still the main cause of coking in furnace tubes. The influence of the change of sealing oil pressure on the radiant feed pump was analyzed emphatically, and the measures to solve the decrease of sealing oil pressure of the radiation feed pump were put forward. The analysis results show that the decrease of sealing oil pressure is caused by the blockage of filter in the inlet pipeline of radiation pump, which needs to be solved by switching to another group of filters. The decrease of sealing oil pressure will accelerate the wear and tear of the end face and cause leakage of the machine seal. The unobstructed condition of inlet filters of other pumps can be judged by referring to the change of sealing oil pressure.
