Targeting reactor network synthesis

Significant recent approaches to chemical reactor network synthesis can be classified into two categories, viz. superstructure optimization and network targeting. In the former, a superstructure is postulated and then an optimal sub-network within it is identified to maximize performance index (Kokossis and Floudas, 1990). 

While synthesis strategies are well developed for energy integration and separation systems, relatively little work has been done in synthesizing reactor networks. This is due to the complex and nonlinear behavior of the reacting system, coupled with the combinatorial aspects inherent in all synthesis problems. This paper provides a brief summary of work to date in this area, focusing on targeting approaches for reactor network synthesis. 

Chapter 1 In this chapter, we introduce the idea of the reactor network synthesis problem and performance targeting. Ultimately, we attempt to articulate two important messages how do you know you have achieved the best You cannot fix what you don t know. 

Balakrishna, S. and Biegler, L.T., 1992b. Targeting strategies for the synthesis and energy integration of non-isothermal reactor networks. Industrial and Engineering Chemistry Research, 31(9), 2152. 

Balakrishna, S. and L. T. Biegler. Targeting Strategies for the Synthesis and Energy Integration of Nonisothermal Reactor Networks. Ind Eng Chem Res 31 2152-2164 (1992). 

S. Balakrishna and L. T. Biegler. A constructive targetting approach for the synthesis of isothermal reactor networks. Ind. Eng. Chem. Res., 31 300, 1992a. 

Given the reaction stoichiometry and rate laws for an isothermal system, a simple representation for targeting of reactor networks is the segregated-flow model (see, e.g., Zwietering, 1959). A schematic of this model is shown in Fig. 2. Here, we assume that only molecules of the same age, t, are perfectly mixed and that molecules of different ages mix only at the reactor exit. The performance of such a model is completely determined by the residence time distribution function,/(f). By finding the optimal/(f) for a specified reactor network objective, one can solve the synthesis problem in the absence of mixing. 

The synthesis problem of a chemical reactor network may be defined as follows. Given the reaction stoichiometry and kinetic expressions, initial feeds, reactor targets (productivity, selectivity, flexibility), technological constraints, the optimal reactor network structure, as well as sub-optimal alternatives. The following elements should be determined ... 

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