Delayed coking process: Delayed coking is similar to thermal cracking, except that it is heated to the temperature required for the coking reaction in a short time, and the raw material is controlled to basically not crack in the furnace tube, but is delayed to the special coke tower for cracking reaction. The delayed coking device is mainly composed of 8 parts: the folding coking part, the main equipment is a heating furnace and a coke tower. There are one furnace and two towers, two furnaces and four towers, and some are directly combined with other devices. In the folding fractionation part, the main equipment is a fractionation tower. In delayed coking, it is generally necessary to add chemicals such as defoamers/scorch inhibitors/liquid yield enhancers. Folding coking gas recovery and desulfurization. The main equipment is absorption tower, desorption tower, stabilization tower, reabsorption tower, etc. Fold the hydraulic decoking part. Taking into account the high hydrocarbon ratio of heavy residual oil, which is very easy to coke, the raw oil is quickly heated to a relatively high temperature (480~500℃), so that the heavy residual oil is too late to react in the tubular heating furnace. It is sent to a hollow container (called coke tower), where the heated oil undergoes cracking and condensation reaction. Heating and coking do not occur at the same time, so it is called delayed coking. The 415℃ high-temperature oil and gas generated by the cracking reaction in the coke tower escapes from the top of the coke tower into the feed section of the lower section of the main fractionation tower. After washing the coke particles carried by the washing plate (herringbone baffle), it rises from the evaporation section and enters the wax oil. Distillation and separation above the oil collection tank, fractional distillation of rich gas, gasoline, diesel and light and heavy wax oil fractions, while the coke formed by the condensation reaction in the coke tower remains in the coke tower, when the coke tower has reached a certain degree of coking, switch to another The coke drum continues to be coked into coke, while the original coke drum performs coke cleaning operations. Usually 2 to 4 coke towers are often used in a coking unit. The coke cleaning adopts the hydraulic decoking method. First, a hole is drilled in the center of the coke layer with a drill, from the top to the bottom, and then high-pressure water with a pressure of 12 to 30 MPa is introduced from the bottom to the top. The impact of the water is used to beat the coke. Come down and drain from the bottom. The high-pressure water delivered by the high-pressure water pump passes through the water line, hose, drill pipe to the nozzle of the hydraulic coke cutter, and the high-pressure water sprayed from the nozzle of the coke cutter forms a high-pressure jet, which uses the powerful impact of the high-pressure jet to remove the oil. The coke is cut down. The drill rod is continuously raised and lowered and rotated until the coke is removed.