Synthesis of optimal serial reactor structures for homogeneous reactions. Part II: Nonisothermal reactors

Abstract

In Part I of this paper a methodology for the synthesis of optimal isothermal serial reactor structures for complex reactions was presented. This has been extended to nonisothermal systems in this paper.A complete review of the relevant background has been included in this paper. A graphical procedure has been presented for Type I1 complex reactions and a computer program has been described for Type I11 complex reactions. Two cases for the Van de Vusse reaction scheme and a naphthalene oxidation example have been used to illustrate the synthesis approach. S. P. CHITRA and RAKESH GOVIND SCOPEThe objective of this research is to find rules and procedures which could be used in specifying the type and arrangement of reactods) to maximize product yield for complex reactions. In Part I of this paper the methodology presented was limited to isothermal systems. In this paper a methodology has been described for the synthesis of serial nonisothermal reactor SYSterns. CONCLUSIONS AND SIGNIFICANCEIn Part I of this paper reactions were classified into three basic types. Type I reactions were called simple reactions, and Types I1 and I11 were denoted complex reactions.From a literature review summarized in this paper, it has been concluded that the rules presented in the literature for adiabatic and nonadiabatic reactor systems are only applicable for simple reactions and in general are not valid for complex reactions.For Type I1 complex reactions a graphical procedure has been INTRODUCTIONIn Part I of this paper a synthesis strategy was proposed for obtaining the optimum serial reactor structure consisting of isothermal reactors, for a Type I1 complex reaction scheme. An optimization strategy and a computer program was also described for obtaining an optimum serial reactor structure for Type 111 complex reactions.As noted in Part I, the objective of our research is to find rules and procedures which could be used in specifying the type and arrangement of the reactor(s) to maximize product yield for complex reactions.Conespndence concerning this paper should he addressed to Rakesh Govind.AlChE Journal (Vol. 31, No. 2) presented for obtaining the optimum temperature profile. Analytical results for obtaining the optimum serial reactor structure have been derived for Type I1 complex reactions. These results have been explained graphically in the form of a stepping procedure described in this paper.For Type I11 reactions an optimization procedure based on the modified complex method has been used to obtain the optimal serial reactor structure. The dominant eigenvalue method is used to converge the calculations.In this paper, the methodology presented earlier for isothermal serial structures will be extended to nonisotherrnal reactor systems.Although preliminary decisions can be made concerning operating temperature and reactor type based on isothermal operation, ultimately it is important to analyze the nonisothermal nature of the system. All industrial reactions are either exothermic or endothermic, and the associated heat eff...

Nonisothermal synthesis of homogeneous and multiphase reactor networks

“…Example 1: Naphthalene oxidation Ž This example has been studied by several groups Chitra and Govind, 1985b;Achenie and Biegler, 1986;Kokossis and . Floudas 1994b , each reporting a different solution.…”

“…It presents a method that is applicable to both homogeneous and multiphase systems. Rather than expanding isothermal Ž superstructures with heat-transfer units Achienie and Biegler, 1988Biegler, , 1990Chitra and Govind, 1985b;Kokossis and . Floudas, 1994a,b;Marcoulaki and Kokossis, 1999 , the article explains the use of temperature profiles and reports benefits over conventional techniques.…”

Investigation on Evolutionary Computation Techniques of a Nonlinear System

“…Optimization approaches initially addressed fixed reactor structures. Examples include the work of Paynter and Haskins [14] and Chitra and Govind [15][16][17]. The first studies of comprehensive structures should be attributed to Achenie and Biegler [18][19][20], who employed existing representations [11,12] to launch optimization techniques in the form of NLP methods.…”

A Structural Disturbance Propagation Model for the Conceptual Design of Highly Controllable Heat-Integrated Reaction Systems

“…Then, mixed integer nonlinear programming (MINLP) techniques are employed to derive optimal designs. On the other hand, heuristic approaches utilize various effective heuristic rules and=or functions to quickly derive highly desirable reactor system alternatives (Douglas, 1985;Chitra and Govind, 1985;Jacobs et al, 1996). By nature, heuristic approaches do not offer optimality.…”