Experimental Study Of Coal Mine Ventilation Air Methane Preheat Catalytic Oxidation

More than twenty billion cubic meters of methane is discharged each yeah in China,80 percent of the coal mine methane is of ultra-low concentration,which has the quality of huge volume,low concentration and it fluctuate strongly in amount and concentration.So most of methane is discharged without any treatment,as a result,environment pollution and energy waste is increasingly serious.So it is of vital importance to study new technology dealing with ultra-low concentration methane.The characteristic of a late-model preheat catalytic oxidation device was experimentally studied in this paper.Before that,some improvements and new design were done to keep the device self-running.Then lots of experiments were done to study the performance of the device,the contents are as follows:(1)The study of starting performance shows that,with the increase of flow rate,the heating rate decrease,and the temperature of oxidation bed is more even;with the increase of heating power,the heating rate increase,and the evenness of temperature in oxidation bed is worse;the best coefficient of flow rate is between 0.3 and 0.4,the lowest starting power is 0.03kW/m3,and the optimum starting power is 1.3-1.6 times of the lowest starting power.(2)The study of oxidizing performance shows that,with the increase of flow rate,the temperature in oxidation bed and the conversion rate of methane increase slowly then decreases rapidly,the efficiency of energy recovering decreases rapidly,and the temperature of exhaust gas increases slightly;with the increases of concentration of methane,the temperature in oxidation bed and the conversion rate of methane increase,the efficiency of energy recovering increases,and the temperature of exhaust gas increases slightly;with the increase of temperature of oxidation bed entrance,the temperature in oxidation bed and the conversion rate of methane increase,the efficiency of energy recovering increases,and the temperature of exhaust gas increases to some extent.(3)The study of resistance characteristics shows that,resistance loss in each part increases with the increase of flow rate,but the pattern are different:the resistance loss in preheater increase quadratic,the resistance loss in oxidation bed increase linearly;resistance loss in each part increases with the increase of temperature in oxidation bed,but the pattern are different:the resistance loss in preheater increase quadratic,the resistance loss in oxidation bed increase linearly;empirical formula of the device was got on the basic of lots experiments.