Isothermal reactor concepts economic evaluation

An isothermal reactor concept incorporating a ceramic membrane is more attractive compared to an adiabatic reactor concept from a thermodynamic point of view. In this concept we assumed a reactor with reactor tubes located in a direct-fired heater and operated in a cyclic way to remove coke formed on the catalyst. Parallel bed and heaters have been assumed [35-37]. 

On behalf of KTI an experimental programme on these reactor concepts has been started at the University of Southern California (USC). Some of the experimental results, concerning the use of Knudsen diffusion membranes are available in the literature [32,40]. These data have been used to calculate the economics of an isothermal propane dehydrogenation membrane reactor concept and are compared with the commercial Oleflex and Catofin processes, based on an adiabatic concept. The experimental circumstances of these lab-scale experiments, especially residence time, pressures and gas composition are not the same as in commercial, large-scale processes. However, we do not expect these differences to have a great influence on the results of the work presented here. 

Two process flow diagrams have been developed for a ceramic membrane reactor process  

The operating characteristics of these processes are given in Table 14.5. 

The design capacity of the plant is 150,000 MT/year polymer grade propylene, which is equivalent to a production of 18,750 kg/h (8,000 h/year). 

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