RSV乙烷回收影响CO2固体形成因素分析

对RSV流程CO2固体形成进行分析,重点分析RSV流程关键参数对CO2固体形成的影响、各关键参数对CO2固体形成、乙烷回收率、主体装置总压缩功的敏感性、RSV流程对原料气CO2含量的适应性。分析结果表明:为避免乙烷回收装置CO2固体形成,可提高脱甲烷塔塔压、降低低温分离器温度、增加低温分离器气相过冷量、减少外输气回流量、增加低温分离器液相过冷量、降低第二股进料位置或升高膨胀机进料位置。各关键参数对CO2固体形成的影响强弱依次为:脱甲烷塔塔压、低温分离器温度、低温分离器气相过冷比、低温分离器液相过冷比、外输气回流比。RSV流程对于CO2含量高于2%的较贫气质适应性较弱,原料气CO2含量越高、压力越低、原料气气质越贫,CO2冻堵控制难度越大。

Analysis on factors affecting the formation of CO2 solids by RSV ethane recovery

The factors affecting the formation of CO2 solids in RSV process were analyzed. The influence of key parameters of RSV process on the formation of CO2 solids,the sensitivity of each key parameter to CO2 solid formation,ethane recovery rate,total compression of main unit and the adaptability of the RSV process on CO2 content of the feed gas were analyzed. The analysis results show that the formation of CO2 solids in the ethane recovery unit can be avoided by increasing the demethanization tower pressure,lowering the temperature of the low temperature separator,raising the gas phase supercooling amount of the low temperature separator,reducing the external gas return flow rate,adding the low temperature separator liquid phase, lowering the second feed position or raising the expander feed position. The influence of each key parameter on the formation of CO2 solids is as follows:demethanization tower pressure,low temperature separator temperature,low temperature separator gas supercooling ratio,low temperature separator liquid supercooling ratio,and external gas reflux ratio. The RSV process is less adaptable to the leaner gas with a CO2 content higher than 2%. The higher the CO2 content of the feed gas,the lower the pressure,and the poorer the gas quality of the feedstock,the more difficult the control of CO2 freezing.