Abstract: As a critical piece of equipment in ethylene cracking units, the structural design reliability of the steam drum has a decisive impact on the long-term safe operation of the entire plant. This paper systematically analyzes the structural configurations of the internal gas-liquid separation devices within high-pressure steam drums for large ethylene cracking furnaces. It clarifies the key requirements for separation efficiency and pressure drop, with a focused discussion on the influence mechanism of the structural parameters of the wire mesh demister on separation performance. Meanwhile, corresponding optimized design solutions are proposed for key components such as the boiler feedwater distribution device, supports for large-diameter, long-cylinder steam drums, and manhole structures. Furthermore, essential maintenance points for the safe operation of steam drums are summarized. Based on the structural and design optimizations, the operational reliability of the high-pressure steam drum has been enhanced. This provides effective technical support for the stable operation of the ethylene plant.

Key words: steam drum, gas-liquid separation, wire mesh demister, separation efficiency, boiler feedwater