Abstract: The original operation mode of heating furnace in delayed coking unit of Tianjin Petrochemical Company severely constrain the improvement of process load of delayed coking unit. Through optimizing feed mode and water injection mode of heating furnace and replacing burner, the process load of the delayed coking unit is increased by 10% over the designed value, and light oil yields of the whole factory is increased by 1. 7%, realizing an annual additional economic benefits of 51. 3 million RMB.