Process synthesis mixing

AGB stars constitute excellent laboratories to test the theory of stellar evolution and nucleosynthesis. Their particular internal structure allows two important processes to occur in them. First is the so-called 3(,ldredge-up (3DUP), a mixing mechanism in which the convective envelope penetrates the interior of the star after each thermal instability in the He-shell (thermal pulse, TP). The other is the activation of the s-process synthesis from alpha captures on 13C or/and 22Ne nuclei that generate the necessary neutrons which are subsequently captured by iron-peak nuclei. The repeated operation of TPs and the 3DUP episodes enriches the stellar envelope in newly synthesized elements and transforms the star into a carbon star, if the quantity of carbon added into the envelope is sufficient to increase the C/O ratio above unity. In that way, the atmosphere becomes enriched with the ashes of the above nucleosynthesis processes which can then be detected spectroscopically. 

Ignacio E. Grossmann, Mixed-Integer Optimization Techniques for Algorithmic Process Synthesis... 

Grossmann, I. E. and J. Hooker. Logic Based Approaches for Mixed Integer Programming Models and Their Application in Process Synthesis. FOCAPD Proceedings, AIChE Symp. Ser. 96 (323) 70-83 (2000). 

Raman, R. and I. E. Grossmann. Symbolic Integration of Logic in Mixed Integer Linear Programming Techniques for Process Synthesis. Comput Chem Eng 17 909-928, (1993). 

Grossmann, I.E. and Santibanez, J. (1980) Application of mixed-integer linear programming in process synthesis. Computers el Chemical Engineering, 4, 205. 

In this book we will focus our studies on nonlinear and mixed integer optimization models and present the fundamental theoretical aspects, the algorithmic issues, and their applications in the area of Process Synthesis in chemical engineering. Furthermore, we will restrict our attention to algebraic models with a single objective. The structure of such nonlinear and mixed integer optimization models takes the following form ... 

The mixed discrete-continuous nonlinear nature of the process synthesis problem implies two major challenges which are due to its ... 

This book aims at presenting the fundamentals of nonlinear and mixed-integer optimization, and their applications in the important area of process synthesis and chemical engineering. The first chapter introduces the reader to the generic formulations of this class of optimization problems and presents a number of illustrative applications. For the remaining chapters, the book contains the following three main parts ... 

This book has been prepared keeping in mind that it can be used as a textbook and as a reference. It can be used as a textbook on the fundamentals of nonlinear and mixed-integer optimization and as a reference for special topics in the mixed-integer nonlinear optimization part and the presented application areas. Material in this book has been used in graduate level courses in Optimization and Process synthesis at Princeton University, while Parts 1 and 2 were presented in a graduate level course at ETH. Selected material, namely chapters 3,5,7, and 8, has been used in the undergraduate design course at Princeton University as an introduction to optimization and process synthesis. 

A process-synthesis problem can be formulated as a combination of tasks whose goal is the optimization of an economic objective function subject to constraints. Two types of mathematical techniques are the most used mixed-integer linear programming (MILP), and mixed-integer nonlinear programming (MINLP). 

Thus, in ammonia synthesis, mixed oxide base catalysts allowed new progress towards operating conditions (lower pressure) approaching optimal thermodynamic conditions. Catalytic systems of the same type, with high weight productivity, achieved a decrease of up to 35 per cent in the size of the reactor for the synthesis of acrylonitrile by ammoxidation. Also worth mentioning is the vast development enjoyed as catalysis by artificial zeolites (molecular sieves). Their use as a precious metal support, or as a substitute for conventional silico-aluminaies. led to catalytic systems with much higher activity and selectivity in aromatic hydrocarbon conversion processes (xylene isomerization, toluene dismutation), in benzene alkylation, and even in the oxychlorination of ethane to vinyl chloride. 

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