Heterogeneous catalytic processes commercial process technology

The discovery of solid catalysts led to a breakthrough of the chemical process industry. Today most commercial gas-phase catalytic processes are carried out in fixed packed bed reactors. A fixed packed bed reactor consists of a compact, immobile stack of catalyst pellets within a generally vertical vessel. On macroscopic scales the catalyst bed behaves as a porous media. The fixed beds are thus employed as continuous tubular reactors in which the reactive species in the mobile fluid (gas) phase are reacting over the catalyst surface (interior or exterior) in the stationary packed bed. Compared to other reactor types or designs utilizing heterogeneous catalysts, the fixed packed bed reactors are preferred because of simpler technology and ease of operation. 

In conclusion, a fundamental understanding of CFB hydrodynamics continues to lag behind commercial operating experience. Although CFB provides considerable advantages of operational flexibility, concerns about operational complexity and scale-up hinder commercialization of heterogeneous catalytic reactions. Concentrated research in the areas of gas-solid contact in the entry region, effect of internals, riser diameter, and solid fines content is required. The continued interaction between academia and industry, as seen in the four international conferences of CFB technology, will be necessary to further optimize commercial operations but also to further develop revolutionary industrial processes. 

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