The coking heating furnace is the core equipment of this unit. Its function is to heat the residue flowing rapidly in the furnace to a high temperature of about 500°C. Therefore, a high heat transfer rate in the furnace is required to ensure that sufficient heat is provided to the oil in a short time. At the same time, a uniform thermal field is required. Prevent local overheating causing coking of the furnace tube. For this reason, flameless furnace is usually used for delayed coking.