| Adsorption Enhanced Reforming (AER) is a new method for hydrogen production. The equilibrium of the reaction of steam methane reforming has been broken through by using adsorption to remove the CO2. The reaction temperature is reduced from 750～900℃ to 500～650℃, and the methane conversion is increased and 95% hydrogen has been produced directly with a lower residue of CO, CO2 content.This paper studied the method to prepare a new complex catalyst used in AER process for hydrogen production. The composition proportion of the complex catalyst and the reaction conditions and kinetics has been detailed studied.First, a NiO/CaO complex catalyst has been studied according to different precursors, NiO content and CaO content and evaluated the relative properties. The results showed that the catalyst prepared from nickel nitrate has the best performance. The optimal content is NiO 15%, CaO 35%. The package methods by complex catalyst and the mixing of catalyst and the adsorbent were investigated. The experimental results showed that the complex catalyst had a higher H2 yield, higher CH4 conversion and lower residue of CO2 content.The reaction conditions were studied in lab-scaled fixed-bed reactor. The result showed that the complex catalyst reduce the reaction temperature and increase the reaction rate obviously under the temperature of 600～640℃, pressure of 0.2 MPa and ratio of steam to methane 4～6. The H2 yield was above 95%. Increase the reaction pressure was unfavorable to the reaction. Increase the ratio of steam to methane give rise to increase the CH4 conversion and H2 yield significantly. The recommend ratio of steam to methane is 4～5 for the considering of energy saving.Under the temperature of 560～680℃, pressure of 0.2MPa, ratio of steam to methane 4 and CH4 space velocity of 158h-1 the reaction kinetics was studied. A three-sector model was set to describe the kinetics as following:(1) Adsorption enhanced sector model and mechanics(2) Transition sector model and mechanics(3) Equilibrium sector model and mechanicsThe activation energy of adsorption enhanced sector was 236.92kJ·mol-1; the activation energy of transition sector and equilibrium sector were 138.36kJ·mol-1 and 191.30kJ·mol-1. The analytical results of the equations indicate that the calculated data agree well with the experimental data. The average deviation was 3.62%. |
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