Study On CuFe Catalysts For Higher Alcohols Synthesis From Syngas

As an important chemical basic raw material,higher alcohols can be used to produce surfactants,detergents and plasticizers.The production of higher alcohols from synthesis gas is one of the research hotspots in Fischer-Tropsch synthesis,and the preparation of catalysts is the focus of research.In this paper,the CuFe catalyst was prepared by the liquid-phase reduction method.The reaction performance of the catalyst was evaluated in a fixed-bed reactor.The texture properties,reduction performance,and adsorption performance of the catalyst were characterized by using X-ray diffraction(XRD),Ar physical adsorption and desorption,temperature programmed reduction(H2-TPR),and temperature programmed desorption(CO-TPD),field emission scanning electron microscopy(FESEM),and transmission electron microscopy(TEM).Using SiO2,Al2O3 and CeO2 as supports,three supported CuFe catalysts were prepared.The SiO2 support facilitates the dispersion of copper-iron nanoparticles and promotes the reduction of iron species.More Fe active sites are beneficial to CO dissociative adsorption.The catalyst CuFe/SiO2 has a large amount of CO dissociative adsorption,which is conducive to the coupling growth of the carbon chain,showing the higher total alcohol selectivity and the proportion of C6+OH,which are 19.8%and 16.4 wt%,respectively.Al2O3 and CeO2 supports can promote catalyst dispersion,but the distribution of alcohols is mostly short-chain alcohols.The effects of catalyst preparation temperature,dispersant type and dosage,and copper and iron loading on the performance of the catalyst were investigated.The CuFe/SiO2 catalyst prepared under the conditions of 300 ml dispersant and ice-water bath has more metallic Cu amounts,which is conducive to CO insertion to generate alcohols,and the reaction performance is better than that of 150 ml dispersant and the catalyst prepared at room temperature.The addition of dispersant polyacrylic acid can inhibit the reduction of CuFe components and inhibit the production of alcohols.The catalyst CuFe/CeO2-EG prepared under the dispersant of ethylene glycol showed the higher CO conversion and total alcohol selectivity.When the catalyst loading is 40%,the catalyst 40CuFe/CeO2 has higher alcohol selectivity and the proportion of C6+OH on alcohols distribution.The effect of process conditions on the reaction performance of synthesis gas to higher alcohols was studied on CuFe/SiO2 catalyst.The best process conditions were reaction temperature 255℃,pressure 2.5 MPa,space velocity 3500 h-1 and feed gas H2/CO=1.