Catalysts For Steam Reforming Of Biomass Tar To Hydrogen-rich Gas

The tar from the biomass gasification not only decreases the product gas yield, but also leads to pipeline blockage and corrosion of equipment damage.the presence of tar effects the synthesis gas to liquid fuel for the purpose of gas process. It is a challenged problem to remove the tar during the biomass gasification. The External Circulating Concurrent Moving Bed (ECCMB) is developed in our laboratory. It can remove the tar to more synthesis gas. The catalysts are used for continuous recycle and regenerate. The catalysts should have good mechanical strength and recycling property. We prepared the modified olivine supported the nickel catalysts. The catalyst was evaluated using the biomass tar as raw materials in a fixed bed reactor.We prepared the modified olivine (MO) support by mixing through the addition of calcium aluminate cement and graphite, the following is shaping, curing, drying and calcination. The nickel was loaded with nickel nitrate by wetness impregnation, then drying and roasting to obtain the catalysts of loading nickel on the modified olivine(NiO/MO). According to the XRD, TPR, and BET characterization, It increased the BET specific surface area and mesopore for active component supported on MO. It enhanced the interaction between the NiO and carrier, There was the new phase of nickel on the NiO/MO catalysts to stabilize the active component. The 800℃was chosen the regenerate temperature according to investigation of different regeneration temperatures.the (H2+CO)/total product gas reached to 80% after five times regeneration, which was up to 90% of the fresh catalyst. The results showed the catalysts had good regenerability. XRF characterization showed the deactivation of the catalysts was caused by carbon distribution not the lost of active component. The NiO/MO catalysts have good regeneration, it can be used in the ECCMB system.According to the investigation of the addition of MgO, which percent was form 5% to 20%, The 10% MgO was the best addition result. The carbon conversion got to 95% with 10%MgO. Compared to the catalyst which had no MgO, the selectivity of synthesis gas was increased. The excess of MgO addition over 10% had no advantage of the activity of catalyst. Form the curves of TG, the carbon deposits decreased with the increasing of MgO. There was no carbon deposits with 15% and 20% MgO. The carbon deposit was decreased 1.57% between the 10% MgO and no MgO.Form the addition of Fe2O3, The iron- nickel catalyst had good catalytic ability by impregnation through the iron and nickel solution. The average of synthesis gas got to 85%. The catalytic ability was better than the catalyst with no iron. Form the steam to carbon(S/C), The iron- nickel catalyst was used at the low S/C, the high S/C made the catalyst poisoned.Compared to the commerce catalyst Z418, it was found the NiO/MO catalysts had better carbon conversion than Z418. From the the calcination temperature, the catalysts had the best catalytic ability at the 1000℃calcination.the blending method is simple, conserving energy, reducing the cost and requiring the gas steam, it can be used in the ECCMB system.