某处理能力6×106m3/d天然气处理厂拟采用干气循环（RSV）工艺回收液化乙烷产品，CO2在脱甲烷塔中发生冻堵是影响天然气乙烷回收装置稳定运行的关键技术瓶颈。以提高乙烷回收率为目标，根据天然气生产液化乙烷工艺选择和CO2冻堵形成机理，模拟不同CO2含量下脱甲烷塔各塔板CO2分布、各塔板温度，通过模拟曲线对比分析得到结论：当进冷箱原料气中CO2含量小于5×10-5时，脱甲烷塔不会发生冻堵。根据不同脱碳工艺分析，选择醇胺法脱除CO2达到工艺需求。研究结果表明，通过采用PZ+MDEA溶液脱除原料天然气中CO2，可有效解决-90~-105℃深冷区的CO2冻堵问题，同时乙烷回收率可达到95%以上。

A natural gas processing plant with a capacity of 6×106m3/d plans to adopt the recycle split-vapor （RSV） process to recover liquefied ethane. CO2 freezing and plugging in the demethane tower is a key technical bottleneck affecting the stable operation. With the goal of improving the ethane yield， according to the selection of liquefied ethane process for natural gas production and the formation mechanism of CO2 freeze blockage， the CO2 distribution and temperature of each tower plate of each tower plate under different CO2 contents were simulated. Through the simulation curve comparison analysis， the conclusion was concluded that when the CO2 content of the raw gas in the cold box was less than 5×10-5， the demethanizer would not freeze blockage. According to the analysis of different decarbonization processes， the alcohol amine method is selected to remove CO2 to meet the process requirements. The research results show that by using PZ+MDEA solution to remove CO2 from raw natural gas， the problem of freezing and blocking of CO2 in the deep cold zone between -90℃ and -105℃ can be effectively solved， and the ethane yield can reach more than 95%.