Study On Preparation Of Catalyst And Combustion Performance Of Benzene

At present, catalytic combustion is the most commonly used technology at home andabroad when it comes to dealing with volatile organic compounds (VOCs). The factors thatinfluence the catalytic combustion efficiency in this technology is the performance, type anddispersion of active components of catalyst carrier. Transition metal catalysts due to theiradvantages of low cost and high catalytic activity are widely studied. So the hotspot in thefield of organic catalytic combustion is to make catalyst of high efficiency, low price andgood stability.In this thesis, The γ-Al2O3monolith support with high surface area and wide pore sizedistribution was prepared by extruding of a mixture of pseudo boehmite，organic aditives，subsequent drying and calculation, and with the equal volume impregnation methodsingle-component CuO/γ-A12O3catalyst, different mole ratio of copper manganese, copperchromium, copper molybdenum compound oxide catalysts（3:1,1:1,1:3,3:1） are alsomade. This thesis investigates the activity of the catalytic combustion of benzene of thesecompound oxide catalysts and characterized the catalytic structures with low temperaturenitrogen adsorption, X ray diffraction (XRD) and temperature programmed reduction(TPR).The result of the experiment of evaluation of benzene catalytic combustion activityshows that：(1) With the increase of CuO content,benzene catalytic combustion activity firstincreased and then decreased in the range of200-300℃.Benzene would burn completelyand degrade into CO2and H2O in the case that load of14%CuO/γ-A12O3catalyst in1800h-1space velocity,with1800mg/m3benzene inlet concentration under the temperatureof350℃.(2) while copper manganese compound oxide catalyst would show higher activitycomparing to copper manganese, copper chromium, copper molybdenum compound oxide catalyst. In addition, under the temperature of250℃with the same experimental conditions,the conversion rate of catalytic combustion of benzene reached100%. Through a variety ofmeans, the most active mole ratio for bi-component composite oxide catalyst is verified tobe1:3,two kinds of active component of the total looad of14%.(3) load double component catalyst activity was significantly higher than that of singlecomponent catalyst.The catalytic activity of the order:Cu(1)-Mn(3)＞Cu(1)-Cr(3)＞Cu(1)-Mo(3)＞Cu-14.Based on the result above, the influence of process conditions (including benzene inletconcentration, space velocity) on a fixed bed reactor to the properties and stability ofcatalyst is further investigated. The result shows that benzene inlet concentration within acertain range fluctuation had less effect while space velocity had more effect. To be detailed,when space velocity is under10000h-1, the catalytic burning conversion rate is about98%with slow falling speed, while space velocity is in the range of10000h-1~18000h-1, the ratedecline rapidly. And the70h stability experiment showed that benzene catalytic combustionactivity remain the same.This is can remain above97.7%.BET and TPR showed thatCu(1)-Mn(3) catalyst have a perfect benzene catalytic combustion activity,it has strongability of resistance to carbon deposition and poison resistance.