Study On Catalysts And Technology Of Methanol Synthesis From Biomss Syngas

With declining reserves of fossil fuels and the threat of global climate deterioration caused largely by the combustion of fossil fuels, the search for a renewable substitute as raw material to replace petroleum has been intensified all over the world. Since biomass feedstock is clean, cheap and renewable, the developments and utilizations of the biomass resources areprospective in the future. Methanol synthesis via biomass syngas, highly efficient and low-cost, has already been suggested as a way of utilizing biomass.Through the study of the technology and catalysts of methanol synthesis from biomass syngas, data related to methanol synthesis of biomass syngas has been achieved, and the rules concluded. The catalytic test of methanol for biomass syngas were carried out in an integral micro-reactor, and the catalysts were characterized by the means of XRDn SEM and XPS. The major achievements are:Four kinds of raw gas, such as biomass syngas (VCO:VH2:VCO2:VN2= 22:47:27:4), industrial syngas (VCo:Vh2:Vco2:VN2=27: 66: 3: 4) , reformed biomass syngas (VCO: Vh2:VCo2: VN2=36:55:5:4 ) and hydrogen added biomass syngas (VcO:Vh2:Vco2: Vn2=:64:14:18:4) , were used inmethanol synthesis experiments. It was found that the conversion of CO fluctuated greatly with temperature, pressure or (and) space velocitychanging, but the conversion of CO2 fluctuated slightly and maintained ata low level (0.6%~4%). By contrast with the yield of methanol from CO2-low gas, that from CO2 -rich gas was about 20% lower, but the selectivity of methanol in liquid products from CO2 -rich gas was just 2%~3% lower than that from CO2 -low gas. In addition, high concentration of carbon dioxide resulted in the rising of optimal temperature , from 250℃ in CO2-low atmosphere to 255℃ in CO2-rich one. In our experiments, the order of the methanol yields is industrial syngas > reformed biomass-gas > hydrogen added biomass-gas > biomass-gas.The experiments of methanol synthesis from biomass syngas were carried out on different catalysts. The results showed that the activity of the Cu-Zn catalyst for methanol synthesis decreased with the reaction time, and reduced by 15% after running for 40 hours. The addition of Al could enhance the stability of the Cu-Zn catalyst. As XRD and SEM shown, the addition of Cr, Zr and Li improved the dispersion of CuO, but the addition of Ce reduced that of CuO. The order of different catalysts activities in methanol synthesis from biomass syn-gas was Li2O (5%) , Cr2O3(1 %) > Cr2O3(0.5%) ≈ ZrO2 (2% ) > CeO2 (2%) > Cr2O3(5%), and which in industrial syngas atmosphere was Li2O (5%) > Cr2O3(1%) >...