Improving batch reactors using attainable regions: Towards automated construction of the attainable region and its application to batch reactors

摘要

The Attainable Region is the set of all achievable states, for all possible reactorudconfigurations, obtained by reaction and mixing alone. It is a geometric methodudthat is effective in addressing problems found in reactor network synthesis. For thisudreason, Attainable Region theory assists towards a better understanding of systemsudof complex reaction networks and the issues encountered by these systems.udThis thesis aims to address two areas in Attainable Region theory:ud1. To help improve the design and operation of batch reactors using AttainableudRegions.ud2. To further advance knowledge and understanding of efficient Attainable Regionudconstruction methods.udUsing fundamental concepts of mixing and attainability established by AttainableudRegion theory, a graphical method of identifying opportunities for improving theudproduction rate from batch reactors is first presented. It is found that by modifyingudthe initial concentration of the batch, overall production performance mayudbe improved. This may be achieved in practice by retaining a fraction of the finaludproduct volume and mixing with fresh feed material for subsequent cycles. This resultudis counter-intuitive to the normal method of batch operation. Bypassing of feedudmay also be used to improve production rate for exit concentrations not associatedudwith the optimal concentration. The graphical approach also allows optimisation ofudbatches where only experimental data are given.udAn improved method of candidate Attainable Region construction, based onudan existing bounding hyperplanes approach is then presented. The method uses audplane rotation about existing extreme points to eliminate unachievable regions fromudan initial bounding set. The algorithm is shown to be faster and has been extendedudto include construction of candidate Attainable Regions involving non-isothermaludkinetics in concentration and concentration-time space.udWith the ideas obtained above, the application of Attainable Regions to batchudreactor configurations is finally presented. It is shown that with the appropriateudtransformation, results developed from a continuous Attainable Region may be usedudto form a related batch structure. Thus, improvement of batch reactor structures isudalso possible using Attainable Regions. Validation of candidate Attainable Regionsudis carried out with the construction algorithm developed in this work.