正丁烷异构化制异丁烷反应热力学分析及试验研究

THERMODYNAMIC ANALYSIS AND EXPERIMENTAL STUDY ON THE ISOMERIZATION OF n-BUTANE TO ISOBUTANE

在分析正丁烷异构化制异丁烷反应特点的基础上,通过系统的热力学计算,获得了不同反应温度下目标反应的标准摩尔焓变、标准摩尔吉布斯自由能变、标准平衡常数及正丁烷平衡转化率,并以Pt/Al_(2)O_(3)-Cl为催化剂进行了正丁烷异构化反应试验研究。结果表明,正丁烷异构化属微放热反应,降低反应温度可提高正丁烷的平衡转化率;对于Pt/Al_(2)O_(3)-Cl催化正丁烷异构化反应,反应温度、反应压力、正丁烷进料空速和氢/烃摩尔比均对正丁烷转化率有较明显的影响,选择合适的反应温度和压力,并适当降低进料空速和氢/烃摩尔比,有利于提高正丁烷转化率;在优化的反应条件下,正丁烷的试验转化率与热力学平衡转化率基本吻合,验证了热力学分析结果的可靠性。

Based on the analysis of the reaction characteristic and thermodynamic behaviors of n-butane isomerization to isobutane,standard molar enthalpy change,standard molar Gibbs free energy change,standard equilibrium constant and equilibrium conversion of n-butane at different temperatures were obtained,and the n-butane isomerization over Pt/Al_(2)O_(3)-Cl catalyst was investigated.The results show that the isomerization of n-butane is an exothermic reaction,and the equilibrium conversion of n-butane can be increased by lowering the reaction temperature.In the n-butane isomerization catalyzed by Pt/Al_(2)O_(3)-Cl,the reaction temperature,reaction pressure,space velocity of n-butane and molar ratio of hydrogen to hydrocarbon(H_(2)/HC)have obvious effects on the conversion of n-butane.The n-butane conversion can be increased by selecting reaction temperature and pressure carefully and decreasing n-butane space velocity and H_(2)/HC molar ratio properly.Under optimum reaction conditions,the conversion of n-butane was in good agreement with that of thermodynamic equilibrium,which proved the reliability of thermodynamic analysis.