Preparation Of Ni-based Catalysts And Their Catalytic Performance In Reforming For Hydrogen Production

With the depletion of fossil fuel as well as the worsening of environmental pollution, H2has drawn more and more attention as a clean, pollution-free and high-efficient energy. With the development of the solid fuel cell hydrogen fuel, hydrogen production techniques are made small and convenient. As a kind of liquid hydrocarbon fuels, Aviation kerosene contains rich H that is used to improve the anti-coking of aerospace engines, and also applies to the energy for the spacecraft and fuel cell.The nickel-based catalysts supported on MgO were prepared by coprecipitation in steam reforming of kerosene for hydrogen.The impacts of the performance were investigated in aspcets of different precipitating agents, supports, calcining temperatures, nickel content, reaction temperatures, water-carbon ratios as well as other factors affecting the catalysts. The characterizations of catalysts were analysized by thermal gravimetric analysis (TG-DTA), X-ray diffraction (XRD), scanning electron microscopy (SEM) and other characterization methods. With NaOH as precipitating agent, polyvinylpyrrolidone (PVP) as template to prepare24%Ni/MgO catalyst shows high mechanical strength and good thermal stability. The active component of Ni and MgO support make an interaction to generate MgNiO2which can help to improve the catalytic activity. Under the conditions of773K and space velocity of2340h"’, catalytic activity is high but stability is poor in15h. The surface of catalyst was deposited by large amounts of carbon after reacting for30h, which also contributed to the deactivation of the catalyst faster.The Ni-M/MgO catalysts were prepared by containing additives M (M=Ce, Co, La). The effects of hydrogen production were inspected in different preparation methods, varius types of additives, reaction temperatures and steam to carbon ratios in steam reforming of kerosene. The results show that Ce can effectively improve the catalytic activity than Co, La in the reaction of10hour and the conversion rate of kerosene remained stable at90%. Highly dispersed CeO2on the surface of catalyst is favorable to improve the catalytic activity and resists the deposition of carbon. Under the conditions of773K, the space velocity of2340h-1and steam to carbon ratios of4.0, Ni-Ce/MgO catalyst that prepared by co-precipitation method shows high activity and stability than non-additive of Ni/MgO catalyst.