二氧化碳在环烷烃中的溶解度和体积膨胀

Solubility of CO_2 in cycloalkanes and cycloalkane volume expansion

为研究环烷烃对注CO_2提高采收率效果的影响,利用PVT仪测量了在不同温度、压力条件下CO_2在环己烷(CH)和甲基环己烷(MCH)中的溶解度和在溶解了气体之后环烷烃的体积膨胀系数,并系统讨论了温度、压力、分子结构对溶解度、体积膨胀系数的影响,使用扩展的Chrastil模型关联了实验数据。研究表明:温度不利于CO_2在环烷烃中的溶解,压力增加溶解度增大。当环己烷上的氢原子被甲基取代后,溶解度略有降低。体积膨胀系数和溶解度随温度、压力、分子结构的变化趋势一致。膨胀系数受到CO_2在环烷烃中溶解度的影响。扩展的Chrastil模型的关联效果较好,最大平均相对误差为2.8%。

To study the effect of cycloalkanes on CO2 enhanced oil recovery,the solubility of CO2 in cyclohexane（CH） and methyl cyclohexane（MCH） and the volume expansion factor of cycloalkanes after CO2 dissolution at various temperatures and pressures were investigated using a pressure-volume-temperature（PVT） apparatus. The impact of temperature,pressure,molecular structure on solubility of CO2 in cycloalkanes and volume expansion factor was systemically discussed. The extended Chrastil model was used to correlate the experimental data. The research shows that increasing temperature is not benefit for CO2 dissolution and the CO2 solubility will increase with the pressure increasing in both CH and MCH. When the hydrogen atom on CH is replaced by a methyl,the solubility in CH will be a little lower. Volume expansion factor and solubility have a same variation tendency with temperature,pressure and molecular structure. The volume expansion factor is influenced by solubility of CO2 in cycloalkanes. The extended Chrastil model has a good correlation result and the maximum average relative deviation is 2. 8%.