Global Optimization Of Noble-Metal Catalyst Pellet And Fixed-Bed Reactor

In this work, optimal engineering design of a noble-metal catalyst, specialization of the catalyst pellet shape and the global optimization of fixed-bed reactor were extensively and thoroughly studied, taking the industrial gas-phase catalytic acetoxidation of ethylene as the target reaction.Firstly, the effects of the location of active layer in the catalyst on pellet activity and selectivity and the method to define its optimal location as well as the criterion of the existence of unique steady state were analytically discussed on the basis of the theory of optimal activity distribution of catalyst pellet. The results showed that under normal conditions, the optimal location (x_η) for activity will be in the inner layer of pellet, but the optimal location (x_δ) for selectivity is in the outer layer of pellet. For pellets with isothermal parallel two-reactar.ts reactions of low heat-effect. x_η>x_δ, and the optimal location (x_opt) by considering ccmpromisingly the activity and selectivity should be between x_η and x_s. Furthermore, the closer the approach of the active layer to the pellet center, the easier the happening of multiple steady state.In order to develop a catalyst with high activity and selectivity and to optimize the fixed—bed reactor, instrinsic and macro reaction kinetics for CT-II catalyst (Chinese - made) as well as the macro reaction kinetics of Bayer— I catalyst (German — made) were experimentally determined. The mechanism of the main reaction (Vinyl acetate...