Liquid fuel production from syngas using bifunctional CuO–CoO–Cr2O3 catalyst mixed with MFI zeolite

Abstract

CuO–CoO–Cr2O3 mixed with MFI Zeolite (Si/Al=35) prepared by co-precipitation was used for synthesis gas conversion to long chain hydrocarbon fuel. CuO–CoO–Cr2O3 catalyst was prepared by co-precipitation method using citric acid as complexant with physicochemical characterization by BET, TPR, TGA, XRD, H2-chemisorptions, SEM and TEM techniques. The conversion experiments were carried out in a fixed bed reactor, with different temperatures (225–325°C), gas hourly space velocity (457 to 850h−1) and pressure (28–38atm). The key products of the reaction were analyzed by gas chromatography mass spectroscopy (GC-MS). Significantly high yields of liquid aromatic hydrocarbon products were obtained over this catalyst. Higher temperature and pressure favored the CO conversion and formation of these liquid (C5–C15) hydrocarbons. Higher selectivity of C5+hydrocarbons observed at lower H2/CO ratio and GHSV of the feed gas. On the other hand high yields of methane resulted, with a decrease in C5+ to C11+ fractions at lower GHSV. Addition of MFI Zeolite (Si/Al=35) to catalyst CuO–CoO–Cr2O3 resulted a high conversion of CO-hydrogenation, which may be due to its large surface area and small particle size creating more active sites. The homogeneity of various components was also helpful to enhance the synergistic effect of Co promoters.