Abstract: In 2022, fire and explosion accidents caused by material leakage occurred frequently in chemical devices. Among them, the thought-provoking accident was an explosion and combustion accident that occurred in the quench heat exchanger of a cracking furnace in an ethylene plant during the feeding process. Based on the results of the accident investigation report, the safe operation status of the quench heat exchanger of the cracking furnace of an 800 kt/a steam cracking unit was analyzed by using the safety analysis methods of the accident tree analysis and the event tree analysis. The main danger and harmful factors existed in it were checked and identified. Measures to prevent or reduce its danger and improve the safe operation of the device were proposed.

Key words: ethylene plant, cracking furnace, fault tree analysis/FTA, event tree analysis/ETA, quench heat exchanger