Epoxidation Of Ethylene Over Monolithic Catalysts And Reactor Simulation

Monolithic catalysts, made of a set of narrow paralleled paths, offer someadvantages as low-pressure drop, near ideal flow pattern and higher catalystutilization compared with traditional pellet catalysts. Nowadays, monolithic catalystshave been widely used in the field of environmental protection such as automotiveand stationary emission control. They have also proved huge potentials in fields ofmethanation, water gas shift, steam reforming, hydrogenation, dehydrogenation andselective oxidation, especially in the field of gas-liquid-solid react. But many of theseare just at beginning of research in laboratory.There are many research publications about ethylene oxide synthesized ontraditional pellet Ag-catalyst, but only one on monolithic catalyst was found.This paper includes three parts: iolite monolithic supports was impregnated intothe argentamine to prepare Ag-catalysts used in the react of ethylene selective oxide,which was different from researches presently;influences of process parameters, suchas reaction temperature, composition of feed gas, as well as space velocity on thereaction conversation and selectivity were investigated;at the same time, models ofthe monolithic reactor were proposed.The molecular formula of iolite is 2MgO·2Al2O3·5SiO2. Specific surface area ofthe monolithic iolite used in this paper is about 10 m2/g. Through SEM we canobserve many Ag-granules, which are globular, about 0.2μm wide, and distributeuniformly on the surface of supports. The ethylene oxide selectivity, which hasreached about 81% with no catalyst promoters, no inhibitor in feed gas, atmosphereprocess, as well as air been used as oxidant, comes near the selectivity of commercialproduction. So we can arrive at a conclusion that monolithic catalysts have somepotential in the reaction of ethylene selective oxide. We can also come to a conclusionthat the feasible reaction condition is at temperature 230℃~270℃, SV 100~250h-1and4% ethylene of feed gas according to the experiment. The monolithic reactor issimulated with one-dimension pseudo-homogeneous model on the basis of thekinetics equation of Zhu Bingchen in East China University of Science andTechnology. Model parameters are calculated by MATLAB. The reaction conversionis described exactly by the model, but selectivity of calculation has some differencefrom the experiment. Then a three-dimension model is raised, which brings forth anew idea because of the special monolithic form with triangular cell.