Study On Cu-based Catalysts Of Slurry Bed Synthesis Ethanol From Syngas Prepared By Complete Liquid-phase Technology

Ethanol as a kind of basic chemical raw materials, has a broadapplication value. Because of a shortage of oil and gas resources in Chinaand big consumption for the national economic development, it leads toour country’s oil external dependency increasing year by year and a greatthreat to the national economy and energy security. Converting coal tosyngas and to catalyze it to ethanol is a energy routes of great strategicsignificance. Ethanol has unique superiority of high oxygen content, lowash and sulfur content, low toxicity, as the ideal liquid fuels, and acts asthe best choice of the alternative and saving of petrol. In this paper, aseries of Cu-based catalysts suitable for slurry-bed process were preparedby the technology of complete liquid-phase for the synthesis of ethanolfrom synthetic gas. The catalysts prepared by hydrolytic method andpre-alcoholysis method were characterized by XRD, N2adsorption,NH3-TPD, H2-TPR and XPS. The effect of different ratios of ethanol and ethanediol, the content of potassium, different gel temperature andpremixed way of PVP on the catalysts texture properties and catalyticperformance was investigated. The main conclusions are as follow:1. The catalysts prepared by hydrolytic method and pre-alcoholysismethod have a similar activity and a good stability, and the COconversion can reach to35%.2.The selectivity of ethanol of catalysts prepared by pre-alcoholysismethod has a evident rising trend in the reaction time of48h, reaching10%approximately, then falling rapidly. The catalytic activity of addingpotassium fertilizer catalysts increased slightly, and ethanol selectivitydid not improve very well.3. In pre-alcoholysis method, the catalytic activity of catalystsimproved with the increasing of the proportion of ethanol, and the ethanolselectivity of catalysts improved with the increasing of the proportion ofethanediol. And relatively low content of potassium can improve thecatalytic activity of the catalysts and the selectivity of ethanol, and highercontent of potassium can inhibit the catalytic activity.5. In hydrolysis method, the catalytic activity of catalysts prepared atthe gelling temperature of85℃is best; With the increasing of geltemperature, the ethanol selectivity of catalysts improves. And, thecatalytic activity of catalyst prepared by premixture of PVP with CuZnsolution is best. The CO conversion of catalysts prepared by premixture of PVP with water, nitric acid and CuZn solution improves with theextension of time, and the CO conversion of the catalyst prepared bypremixture of PVP withAl declines with the extension of time.6. The results show that the copper of catalyst was in the form oflow state. The catalytic activity of catalysts associates with reductionpeak temperature, reduction of peak area, acid amount and Cu/Zn ratio onthe surface. And the enrichment degree of Zn on the catalyst surface has arelation with the ethanol selectivity of catalysts. The enrichment degreeof Zn on the catalyst surface is higher, the ethanol selectivity of catalystsis better.