CO+H_2合成醇体系的化学平衡分析

Ananalysisofchemicalequilibriuminsynthesisofhigheralcoholsfromsyngas

对ＣＯ＋Ｈ２合成醇反应体系进行了化学平衡分析，用最小自由能法计算得到不同温度、压力、合成气Ｖ（Ｈ２）／Ｖ（ＣＯ）比和ＣＯ２含量下的产物平衡组成及ＣＯ、Ｈ２的平衡转化率。ΔＧ°的计算表明，热力学上变换反应和生成烯烃的反应都比合成醇反应容易进行，低温对碳数高的醇生成有利，高温对碳数低的醇生成有利。与实验结果的对比表明，在ＺｎＣｒＫ催化剂上由合成气合成醇，在气相和超临界条件下反应，体系中甲醇合成反应和变换反应均接近化学平衡，生成Ｃ２＋ＯＨ的反应远离化学平衡，产物分布受动力学限制，而非受热力学限制。

Ananalysisofchemicalequilibriumisperformedinsynthesisofhigheralcoholsfromsyngas.ThechemicalequilibriumcompositionsofproductsandequilibriumconversionsofCOandH2areobtainedatdifferenttemperatures,pressures,V(H2)/V(CO) ratiosandCO2contentsbyminimizingtheGibbsfreeenergy.Thermodynamically,alkeneformationandgaswatershiftreactionproceedmorereadilythanhigheralcoholsformation.Itisfoundthat,insynthesisofhigheralcoholsfromsyngasoveraZnCrKcatalyst,methanolsynthesisandshiftreactionapproachtochemicalequilibriumbothforgasphasesynthesisat360410,75MPaandGHSV1700h-1andforsupercriticalphasesynthesisatthesameconditionsandareactionmedium(a mixtureofC11C13alkanes)pressureof178MPa,andthatproductdistributionislimitedkinetically,notthermodynamically.