Numerical Simulation Of Ventilation Air Methane Counter-current Oxidation Reaction In Porous Media

In china, a plenty of ventilation air methane (VAM) is directly discharged into theatmosphere every year. Methane included in VAM is the main greenhouse gas, which not onlydestroys the environment, but also the heat quantity cannot be recovered. In this paper, the stablecombustion of VAM is studied for the countercurrent oxidizing reactor in porous media. Thecombustion characteristics of VAM are numerically computed for the countercurrent oxidationin porous media. The countercurrent oxidation technology in porous media can widen the leanflammability limit of methane and realize ultra-low value stable combustion. The quantity ofnitrogen oxides and CO generated owing to combustion is significantly increased during thecountercurrent oxidation. It is an advanced combustion technology with development potential.1D and2D model are presented for the countercurrent oxidation reaction of VAM. Theeffects of different operating parameter on the countercurrent oxidation process of VAM arenumerically studied by applying FLUENT software. Based on the1D model, the pressure andvelocity are coupled by using the SIMPLE algorithm, and the oxidation of CH4is simplified atotal package reaction with a single step. The radiation in porous media is considered, and theeffects of equivalent ratio, half-cycle, velocity and porosity of porous media are analyzed on thecountercurrent oxidation of VAM. The computed results show that the field of temperature incountercurrent oxidation device present trapezium distribution. The equivalent ratio and velocityhave larger effect on the countercurrent oxidation. When the half-cycle is constant, increasingthe equivalent ratio and velocity of CH4/air mixture, the zone with high temperature will becomewidened, and the temperature at exit and maximum temperature are also increased. Thehalf-cycle has little effect on the maximum temperature in the countercurrent oxidation device,but the temperature at exit will increase with increasing the half-cycle. Based on the2D model,the combustion process of CH4and the temperature distribution are analyzed.