乙酸选择性加氢制乙醇反应性能研究

在固定床反应器上考察了反应温度、反应压力、乙酸(HAC)液体进料空速、H_2/HAC(总气体空速GHSV或H_2流量)对乙酸选择性加氢制乙醇反应的影响,研究了乙酸转化率、产物选择性、乙醇时空收率的变化规律,验证了自主开发催化剂的稳定性。结果表明,副产物的选择性受反应条件的影响,选择合适的反应条件可以抑制乙酸乙酯和丙酮的生成。原料与催化剂床层接触时间小于5s时,可以避免发生乙酸加氢分解脱羰反应生成甲烷气相产物,也避免了乙醇的进一步反应生成乙烷。在反应温度为280℃,反应压力为2.5 MPa,乙酸进料液时空速为0.72 h~(-1),H_2/HAC(mol ratio)为16的条件下,乙酸乙酯选择性为6%。900 h长周期实验表明,自主开发催化剂具有较好的工业应用前景。

Study on the selective hydrogenation of acetic acid to ethanol

Effects of temperature, pressure, acetic acid(HAC) feeding rate and H₂/HAC(GHSV or H₂ flow) on the conversion of acetic acid, product selectivities and the productivity of ethanol in selective hydrogenation of acetic acid to ethanol were investigated in a fixed-bed reactor. The good stability of the lab-made catalyst was verified. The results show that the reaction rate of esterification and decarboxylation/ketonization are very fast. Selectivities of ethyl acetate and acetone are affected by the catalyst composition and reaction conditions. The hydrodecarbonylation of acetic acid to methane and the further conversion of ethanol can be avoided when the contact time of the reactants with the catalyst is less than 5 s. Optimum reaction conditions were found at 280 ℃, 2.5 MPa, LHSV=0.72 h^-1, H₂/HAC(mol ratio)=16, under which the selectivity of ethyl acetate could reach 6%.Life time test more than 900 h shows that the lab-made catalyst has a good potential for industrial application.