Ni基催化剂管式固定床甲烷重整反应器中积炭效应的数值模拟

Numerical Simulation of the Carbon Deposition Effect in Tubular Fixed Bed Methane Reforming Reactor Over Ni-Catalyst

在综合考虑积炭效应对催化剂孔隙率以及催化剂活性影响的基础上,通过建立包含动量、能量、质量传递以及化学反应动力学方程的多物理场耦合数值模型,从热质传递的角度,计算了Ni基催化剂管式固定床甲烷重整反应器中的积炭效应,阐明了包含多孔介质催化剂段的反应通道中的速度、温度及压力场分布,并指出了在通道中随气体流动扩散的可移动炭以及催化剂表面沉积炭浓度分布规律,分析了积炭对催化剂孔隙率、活性以及反应通道压降的影响,并进一步讨论了甲烷浓度以及温度对积炭产生的影响,最后提出了消减积炭的方法。

Based on the effects of carbon deposition on catalyst porosity and activity, a multiphysics-coupled numerical model containing the equations of momentum, energy and mass transfer, as well as the chemical reaction kinetics was developed, to simulate the carbon deposition effect in tubular fixed bed methane reforming reactor over Ni-catalyst in the viewpoint of heat and mass transfer. The velocity and temperature field, as well as the pressure distribution in the reaction channel with porous media catalyst section were explained in detail. The distribution rules of movable coke, which is caused by the convection and diffusion, and the deposited coke on catalyst surface in the reaction channel were both pointed out. Meanwhile, the effects of carbon deposition on the porosity and catalyst activity of porous catalyst, as well as the pressure drop in reaction channel, were all discussed. Finally, the effects of methane inlet concentration and temperature on the carbon deposition effect were further analyzed, and the methods for coke elimination were proposed. The developed analytical model described the generation and distribution rules of carbon deposition effect systematically, which is helpful for the further research on the carbon elimination in CH4reforming reaction over Ni-catalyst. © 2016, Science Press. All right reserved.