Objective In order to improve the operational efficiency of ethylene cracking unit, a fast and efficient technical solution for the optimized operation of ethylene cracking furnaces was provided.

Methods The on-site calibration test plan for ethylene cracking furnace was established, the physical properties and composition of cracking raw materials were analyzed. Taking naphtha cracking furnace and hydrogenation tail oil (HTO) cracking furnace as examples, self-developed online sampling devices were utilized to conduct on-site calibration tests for guiding the optimization and adjustment of cracking furnace outlet temperature (COT) for ethylene cracking furnace.

Results The calibration test showed that the optimal COTs for the naphtha cracking furnace and the HTO cracking furnace were 855 ℃ and 830 ℃, respectively. Under the above control temperatures, the yield of diene (ethylene+propylene) and trienee (ethylene+propylene+1,3-butadiene) in the naphtha cracking furnace reached the highest values of 45.53% and 49.15%, respectively. The yield of diene and triene in the HTO cracking furnace reached the highest values of 52.10% and 59.21%, respectively. A significant improvement in yield was obtained.

Conclusions An independently developed online sampling device was used, and the calibration test plan described in this paper was implemented. At production capacity of 800×10³ t/a ethylene cracking unit, on-site calibration tests were conducted on different raw material cracking furnaces to optimize the cracking process, which could effectively improve the yield of cracking target products and achieve the goal of improving the operational efficiency of the ethylene cracking unit.