急冷油黏度控制是决定乙烯装置节能降耗和稳定运行的关键和难点，通过急冷油增黏机理分析，发现急冷油中沥青质含量是导致黏度升高的主要原因。总结了行业内普遍实施的定期引入调质油、设置减黏塔、注入减黏剂等减黏措施，结合生产实际提出了原料结构优化、裂解反应深度控制、塔釜温度控制、焦粉脱除等工艺调整措施，确保急冷油系统高效、稳定、长周期运行。

The control of viscosity of quench oil is the key and difficult point for an ethylene plant to reduce energy consumption and remain stable operation.Through analyzing the viscosity-rising mechanism of quench oil,it is found that the asphaltene content in quench oil is the main reason for the rise in viscosity.General viscosity reduction measurements practiced widely in the industry are summarized,such as regularly adding diesel,installing a viscosity reducing tower,and injecting t viscosity reducer,etc.Combined with actual production,some process adjustment measures are proposed such as feedstocks formula optimization,deeply controlling cracking reaction,control of tower bottom temperature and coke powder removal,aiming to ensure efficient,stable,and long-term operation of the quench oil system.