Studies Of Cyclohexanone Exhaust Low Temperature Degradation By Pt/?-Al₂O₃ Catalyst Combined With Fix Bed Reactor

Catalytic degradation is a highly efficient and clean technology for the degradation of volatile organic pollutants?VOCs?at home and abroad,and it has attracted people's attention and research in the world.Cyclohexanone is very important material,widely used in the manufacture of caprolactam and adipic acid as well as other chemical products.At the same time,it is also a very important chemical solvents,such as a printing and dyeing industry,oil production and pesticide solvent.This researches explored catalytic degradation efficiency under different process parameters,and the mechanism,kinetics and pathways in the fixed bed reactorLow temperature catalytic degradation of cyclohexanone has a lot of advantages,such as the process is safe and reliable,no second pollution,and it has very broad application prospects.During the experiment,the gas chromatograph?GC?was used to measure the changes and to calculate the catalytic degradation efficiency.At the same time using the response surface method?RSM?to optimize parameters.By using gas chromatography mass spectrometry?GC-MS?,Fourier transform infrared spectrometer?FTIR?on the degradation of intermediates,final products were analyzed,and speculated the degradation mechanism.In addition,the catalysts use TEM?through high resolution transmission electron microscopy?XRD?X-ray diffraction?BET?low temperature nitrogen adsorptionand porosity determination?FTIR H2-TPR?hydrogen temperature programmed reduction?to characterize.The experimental points are as follows:1)Experiments was designed by fixed bed catalytic devices.We had made 0.6%,0.8%,1.0% Pt/?-Al₂O₃ catalyst by self-assembly method.And through XRD,TEM and BET?nitrogen adsorption?to characterized the related tests.2)In the fixed bed reactor,using single factor variable method first,then use the RSM to research multifactor interaction and to find the best conditions.Under 235 ?,explored the degradation efficiency of change in 10-70?relative humidity %?,gas concentration of cyclohexanone 500-4000 mg/m3,GHSV 5000-20000h-1.The best degradation condition is for 1992mg/m3? 11788h-1?47.02%?RH?,the efficiency is 89.6%,the actual efficiency is 86.5%.Factosr analysis of contribution degree:concentration×RH > GHSV×RH >.concentration×GHSV.3)Experimental kinetics of reaction is determined by the experiment of necessary conditions;the influence of internal and external diffusion of catalysts is eliminated.The conditions for the cyclohexanone mixed gas flow rate is 200 mL/min,catalyst loading quantity is 0.4g.The cyclohexanone catalytic degradation of order,the reaction activation energy E,refers to the former factor k0 have calculated,and got the cyclohexanone catalytic degradation reaction kinetics equation finally.4)By GC-MS analysis of degradation products,intermediates was toluene,benzene,cyclohexene ketone,methyl cyclopentanone and cyclopentanone;after absorption concentration on degradation products,FTIR analysis of the degradation products are methyl,ethyl,hydroxyl,carboxyl,aldehyde,etc.,and ultimately degradation products are CO2 and H2 O.5)Study of speculate cyclohexanone catalytic degradation is four step reactions: activation of cyclohexanone ortho-position,meta-position,para-position;ring opening reaction and bond rupture;intermediates polymerization reaction and restructuring;free radical oxidation reaction.The ring opening reaction of cyclohexanone is the main way for degradation,realized the purpose of harmless degradation.