The Numerical Simulation On Regenerative Catalytic Oxidation Technology Of Coal Mine Ventilation Air Methane

At present, there are20billion cubic meters of methane emissions through the ventilation air of methane (VAM) in China every year, which is both contributed to the greenhouse effect and a waste of the clean energy. The abatement and effective utilization of VAM is extremely urgent. Flow reversal catalytic oxidation technology is a kind of regenerative oxidation method, which can combust lean methane-air mixture and utilize VAM as low-calorific value fuel. Research and development of this technology is therefore important from both energy-efficient and environmental point of view.In this thesis, an one dimensional heterogeneous continuum model for catalytic flow reversal reactor (CFRR) was established. The model guaranteed both the calculation precision and calculation efficiency. Simulation research work includes the following:(1) Effects of structure parameters on the performance of CFRR. The temperature of the bed increased with the increase of diameter, decreased with the increase of catalytic length in the case of catalyst enough when superficial gas velocity was0.1m/s. The temperature of the bed increased to a certain value and then remained with the increase of regenerative length when superficial gas velocity was0.15m/s. The best bed structure ratio is1.2-2.0with catalytic length0.4m.(2) Effects of operating parameters on the performance of CFRR.The temperature of the bed increased with the increase of inlet concentration, decreased with the increase of extraction rates. Switching period and superficial gas velocity thresholds existed because of their interrelationship.(3) The operating ranges of the reactor at specific inlet concentra-tion and superficial gas velocity.The operating ranges of the reactor were researched when inlet concentration was0.35%and when superficial gas velocity was0.143m/s. It showed that operating parameters needed to be in the certain operating region to insure that the reactor could run normally. When operating parameters was out of the scope, it was necessary to adjust the operating points to return to region in case of overheating and reactor extinction.(4) Research of the regression model of using the operating parameters to predict reactor performanceAn equation of the relationship between the maximum temperature and the operation parameters was deduced with uniform design experiment method. Studies had shown that the interaction between quadratic inlet concentration and the superficial gas velocity had the most significant effects on the reactor performance. The regression model could predict the maximum temperature in the reactor, helpful to reactor control.