Adjustment of the raw material preheating temperature

Previous catalytic cracking units were equipped with heating furnaces. At that time, the technology related to crude oil nozzles was relatively backward; the temperature of the crude oil had to be raised to over 350°C by the heating furnace in order to ensure proper atomization. Later, various advanced nozzles came into use, eliminating the need for high preheating temperatures of the feed materials, and the heating furnaces in catalytic cracking units were also removed. Currently, the crude oil only exchanges heat with several heat sources in the distillation system; a three-way control valve is installed on the exchanger where the slurry meets the crude oil. In practice, however, flow always takes place through the main line, as the heat bypass is generally not used. The preheating temperature of the crude oil can reach at most around 250°C, so no adjustment is necessary.