Simulation And Optimization Of Catalyzed Isotopic Exchange Between Hydrogen And Water In Trickle Bed Reactor

Catalyzed isotopic exchange between hydrogen and water for separation of hydrogen isotopes is prospective during heavy water upgrading for fission reactor and waste water treatment for fusion reactor.A catalytic exchange reactor for deuterium removal from hydrogen of countercurrent trickle bed is simulated based on experiment,packed with a mixture of hydrophobic catalyst and hydrophilic packing.Parameters in correlations for mass transfer coefficient are fitted based on experimental data.Factors affecting deuterium removal efficiency of the pilot industrial non-adiabatic reactor and optimal operation condition is studied by developed model.Based on non-adiabatic reactor model,model for adiabatic reactor is established and its simulation result is compared with non-adiabatic condition.In non-adiabatic reactor,hydrogen humidification occurs mainly at the bottom of the reactor and neglecting its effect on humid as well as flow rates of gas and liquid leads to overestimation of removal percentage of deuterium.Gas-solid catalytic exchange and gas-liquid mass transfer of HDO sequentially limits the overall isotopic exchange rate from top to bottom of reactor and limiting step transforms near the bottom,where hydrogen humidification occurs simultaneously.Gas-solid catalytic exchange is strongly affected by internal diffusion according to low effectiveness factor of catalyst.Operation condition of non-adiabatic reactor is optimized by established model.In adiabatic reactor,axial temperature variance pronouncedly increases.At large molar ratio of gas and liquid feed,gas and liquid temperatures approach each other in the middle of adiabatic reactor.Meanwhile,humidification mainly takes place at the top and bottom of adiabatic reactor,which is relatively insufficient compared with non-adiabatic condition.Thus liquid flow variance and humidity decrease in the reactor.Adiabatic operation therefore improves gas-solid catalytic exchange and resists gas-solid catalytic exchange.However,it little affects effectiveness factor of catalyst.Optimal operation condition of adiabatic reactor is studied and compared with that of non-adiabatic reactor by established model.