Abstract: Since the overhaul of the delayed coking unit in 2016, there have been corrosion on the top of the raw material buffer tank，the feed line on the coke tower，the shell of the reboiler at the bottom of the tower, and the cooler bundle at the top of the tower. The causes of corrosion were analyzed and protective measures were proposed. The short joint corrosion on the top of the raw material buffer tank is high temperature sulfur corrosion, which needs to adopt measures such as material upgrading or pipeline lining. The corrosion of the elbows of the feed line on the coke tower is due to the joint action of low temperature sulfur corrosion and erosion corrosion. The valve should be cut off or added heat tracing at the top of the tower. The corrosion of the reboiler shell at the bottom of the analytical tower is the electrochemical corrosion. It is necessary to control the sulfur content of the raw materials and to upgrade the reboiler equipment. The corrosion of the cooler tube bundles on the top of the stability tower is the inner wall scaling and metal corrosion of the tube bundles.The operation of the device showed that protective measures were proper and the corrosion risk was basically controllable．

Key words: delayed coking, high temperature sulfur corrosion, wet hydrogen sulfide corrosion, metal corrosion, anti-corrosion measure