摘要
乙烯装置自产的甲烷尾气通常用作再生气和裂解炉燃料气,在深冷分离过程中,过多的乙烯损失到尾气中,造成尾气中烯烃浓度过高,对装置的经济性和长周期安全稳定运行带来不利影响。文中结合中石化LECT前脱丙烷前加氢分离流程,分析了高压脱甲烷系统中碳一和碳二分离效率是造成甲烷尾气中烯烃浓度波动的主要原因。通过分析裂解气组成中甲烷/氢气比值较低工况对高压脱甲烷塔系统分离效率的影响,研究了在维持主要分离工艺流程不变,通过优化操作条件和局部流程重构,采用调整脱甲烷塔系统的操作条件、增加循环甲烷、回收尾气中的乙烯等措施,改善塔顶冷凝器的换热效果,控制甲烷尾气中的乙烯量,并对比不同方案对装置投资和运行能耗水平的影响,建立了控制脱甲烷塔系统与甲烷尾气中乙烯浓度的多种方法。
The methane tail gas generated within ethylene plants is typically utilized as regeneration gas and fuel for cracking furnaces.During the cryogenic separation process,excessive ethylene is lost to the tail gas,resulting in a high concentration of olefins in the tail gas,which will have adverse effects on the economy and the long-term safe and stable operation of the plant.Based on the Front-End Depropanizer and C 2 hydrogenation of Sinopec LECT technology,this paper analyzes that the separation efficiency of C 1 and C 2 in the high-pressure demethanizer system is the primary cause of the olefin concentration fluctuations in methane tail gas.By analyzing the influence of low methane/hydrogen ratio in the cracked gas composition on the separation efficiency of high-pressure demethanizer system,this study explores the measures for enhancing the heat exchange efficiency of the overhead condenser and controlling the amount of ethylene in the methane tail gas by optimizing the operating conditions and locally reconstructing the processes while maintaining the primary separation process unchanged.These measures include adjusting the operating conditions of the demethanizer system,increasing the circulation of methane,and recovering ethylene from tail gas.Additionally,the study compares the impact of various schemes on plant investment and operational energy consumption levels,and establishes several methods for controlling the ethylene concentration in the demethanizer system and the methane tail gas.
作者
高斌
赵百仁
Gao Bin;Zhao Bairen(SINOPEC Engineering Incorporation,Beijing,P.C.100101)
出处
《乙烯工业》
2025年第4期1-6,9,I0001,共8页
Ethylene Industry
关键词
深冷系统
脱甲烷塔
甲烷/氢气
膨胀/再压缩机
乙烯损失率
再生气
cryogenic system
demethanizer
methane/hydrogen ratio
expander/recompressor
ethylene loss rate
regeneration gas
