裂解气干燥器运行存在的问题分析与对策

ANALYSIS AND COUNTERMEASURES FOR PROBLEMS IN OPERATION OF CRACKING GAS DRYERS

独山子石化公司1100 kt/a乙烯装置设置2台裂解气干燥器,一开一备,设计在线运行36 h后进行切换、再生操作。依据再生升降温次数对分子筛吸附性能衰减的关系,以及考虑乙烯装置的提质增效,将单台裂解气干燥器在线运行周期延长至72 h,运行11个月出现干燥器压差异常上涨8 kPa,导致裂解气压缩机出口压力上涨,影响装置长满优运行。文中从物料组成、再生介质、残余吸附量、进料温度、再生过程等方面分析与讨论造成压差上涨异常的因素,通过理论计算与实际生产结合,提出并实施了干燥器阶段化运行优化方案,解决其压差上涨异常的问题,实现平稳运行与节约成本的双重结合。

The 1100 kt/a ethylene plant of Dushanzi Petrochemical Company was equipped with two cracking gas dryers,one for operation and one standby.A single dryer was designed to run online for 36 h and then switched for regeneration.The online operation cycle of a single cracking gas dryer was extended to 72 h,in order to reduce the influence of regeneration times on the adsorption performance attenuation of molecular sieve and to respond to the call of ethylene plant to improve quality and efficiency.After 11 months of optimized operation,the pressure difference of the dryer increased by 8 kPa,leading to the increase of outlet pressure of cracking gas compressor and affecting the long-term and optimum operation of the plant at full load.In this paper,the factors causing the abnormal pressure difference rise are analyzed and discussed from the aspects of material composition,regeneration medium,residual adsorption capacity,feed temperature and regeneration process.Through the combination of theoretical calculation with practical production,some measures for optimizing the operation of the dryer in stages were proposed and adopted,solving the problem of abnormal pressure difference rise and realizing both stable operation and cost saving.