Transient response methods for assisted design of gas phase heterogeneous catalysts: experimental techniques and mathematical modeling

The use of transient response techniques to obtain transport and kinetic rate equation parameters for gas-phase heterogeneous catalyzed systems is presented from the perspective of assisted catalyst design. The emphasis here is first placed on providing an overview of the various tasks involved in improving catalyst technology for existing processes, or developing novel catalyst compositions for new processes. Included here is a discussion on the role of various inputs needed to support the catalyst development process, and the role of mathematical models in developing assisted catalyst design concepts. Various laboratory scale reactor systems which can be used to generate some of the needed supporting experimental input information, such as that normally associated with quantitative description of reaction kinetics and mechanisms, are reviewed next. Particular reactor types which are covered here include various versions of fixed-bed pulse reactors, continuous flow stirred tank reactors, and various single-pellet reactors. Key qualitative features of these reactors, including their advantages and disadvantages, are presented along with typical experimental hardware arrangements. The final section reviews mathematical modeling of selected reactor types under transient conditions along with example applications. Recommendations on how transient response techniques can be more directly utilized in assisted catalyst design, and some of the outstanding technical problems that must be overcome, are also summarized.