Catalytic Conversion Of Methanol To Fuels Over Fe-based Metal Oxide Catalysts

Methanol as an important organic solvents and industrial raw materials is widely used. Recently, Methanol conversion to fuel has been studied intensively. There are some conventional ways to convert methanol to other fuels production such as methanol reforming to produce H2, methanol to olefins, propylene and gasoline. This work demonstrates the different catalytic conversion of methanol over Fe-based catalysts. In this process, the in-situ regenerated H2 and CO in the methanol reforming reaction can be used as reaction gas in subsequent Fischer-Tropsch reaction. The Fe-based catalysts catalyze both the methanol reforming reaction and Fischer-Tropsch reaction. This work provides a direct route to convert abundant renewable methanol to liquid fuels. The major work and innovative results for this dissertation are as follows:In the first part of this thesis, MFe2O4(M=Ni, Zn, Mn, Co, Fe) binary metal oxide catalysts were prepared by solvothermal method. They were characterized by multiple methods such as XRD, SEM, N2 adsorption-desorption, H2-TPR and XPS. Meanwhile they were assessed in the catalytic conversion of methanol. The results show that gas products mainly contain H2, CO, CO2, CH4 and small portion of gaseous hydrocarbons such as C2H4, C2H6, C3H6, and C3H8. The M element in MFe2O4(M = Ni, Zn, Mn, Co, Fe) catalyst has a certain influence on the distribution of the liquid product. Among all these catalysts, ZnFe2O4 catalyst exhibits the highest yield of C6–C21 hydrocarbons. The main liquid products are C6–C21 hydrocarbons and the corresponding relative of C6–C21 hydrocarbons in liquid product is as much as 94%.Secondly, in order to find the single metal function and effect of Co element incorporation on MFe2O4, we used the same method to prepared the MO(M = Ni, Zn, Mn, Co, Fe) catalysts and M0.5Co0.5Fe2O4(M=Ni, Zn, Mn) catalysts. Meanwhile they were assessed in the catalytic conversion of methanol. The results show that gas products mainly contain H2, CO, CO2, CH4 and small portion of gaseous hydrocarbons such as C2H4, C2H6, C3H6, and C3H8. After catalysis conversion under Fe3O4, Co3O4 and M0.5Co0.5Fe2O4(M=Ni, Zn, Mn) catalysts, the main liquid product is C6-C21 hydrocarbons. The addition of the third metal component Co has a certain impact on the yield of C6-C21 hydrocarbons. With addition of Co element in MFe2O4, the yield of C6-C21 hydrocarbons decreases and that of CH4 in gas product increases. This is maybe that Co element can promote the methanation reaction.Finally, the effects of reaction temperature, reaction time, catalyst amount and Zn Fe2O4 supported on different carriers on catalytic conversion of methanol over ZnFe2O4 catalyst were studied. The optimized reaction conditions are as follows: the reaction temperature=300℃, the reaction time= 120 min, and the catalyst amount= 0.5 g. Four cycles’ reaction results show that the distribution of gas and liquid products has no obvious change, and the yield and relative content of the C6-C21 hydrocarbons in the liquid product are also stable, indicating Zn Fe2O4 catalyst is stable and reusable in the reaction conditions. After ZnFe2O4 supported on different carriers, yield and relative content of the C6-C21 hydrocarbons in the liquid product decreases.