The Performance Researching Of Methane Catalytic Partial Oxidation On Rhodium-based Catalyst

With using methane reforming to syngas, and then use syngas to take a series of chemical products, natural gas is currently the most widely used chemical in a technical route. The main industrial production by steam reforming process syngas, but its investment, high energy consumption, the product is not conducive to the synthesis of methanol and F-T. At present, the catalytic partial oxidation of methane technology has been into the line of sight of researchers, which has a small investment, low energy consumption, mild reaction, and higher efficiency, suitable for large airspeed conditions. Also, the product is perfect for the synthesis of methanol and F-T synthesis. However, catalytic partial oxidation of methane technology also has many technical problems, such as non-precious metal catalyst, it has low activity, and easy to deactivation for coking, there is a hot issue during the reaction easily lead coked catalyst deactivation. This paper was prepared using different forms of precious metal Rh-based catalyst over saturation impregnation method, by SEM, XRD and gas chromatography(GC) to study the dispersion of the active ingredient of the prepared resulting catalyst, catalytic activity and selective activity under different conditions, thermal stability and prohibit to sulfur poisoning characteristics at a constant temperature and intake air conditions. The main conclusions are as follows:(1) To increase the amount of the active ingredient will reduce the load on the carrier surface dispersion, particulate CH4 completely oxidized Rh easy to make, adding La, Ce, Zr, Ti helps to improve the dispersion of Rh in the surface of the carrier, and also helps to improve the thermal stability of the catalyst. However, the four metal additives(La, Ce, Zr, Ti) did not significantly enhance the catalyst added resistance to sulfur poisoning.(2) The catalyst activity and selectivity with increasing Rh content of the active ingredient exhibits a reduced tendency increases first and then, the 0.5Rh catalyst having optimum activity and selectivity of the synthesis gas. With increasing temperature and catalyst activity selective show a gradual upward trend, and the large temperature effect on the activity and selectivity of the catalyst activity and selectivity best at 750 ℃. CH4 and H2 conversion activity with the intake air flow rate of selectivity decreases, and CO with the intake air flow rate increases. With increasing the CH4 concentration, the catalyst activity and selectivity decreased.(3) Adding La, Ce, Zr, Ti will help improve the catalyst activity, but with the ability to store oxygen additives(Ce, Zr, Ti) is easy to complete oxidation of CH4 to H2 O and CO2, it will reduce the selectivity of the catalyst, which 3La-0.5Rh, 3Ce-0.5Rh, 3Zr-0.5Rh and 5Ti-0.5Rh exhibit excellent catalytic activity and selectivity. While 3Zr-0.5Rh showed the best catalytic activity and selectivity in the synthesis gas for CO / H2≈1 / 2.(4) Rh-based catalyst catalytic partial oxidation of methane to follow the direct reaction mechanism, the reaction process containing CH4-H2 O reforming reaction and the water gas shift reaction, but no CH4-CO2 reforming reaction.