Design and Optimization Procedure

This process has two design optimization variables. We select the reactor inlet temperature 7in and the ratio of the reactant concentrations in the recycle stream v a/ b- Therefore the optimization problem involves a two-dimensional search for the values of these two variables that minimize the total annual cost of the process. The steps in the design procedure are detailed below  

Pick a reactor inlet temperature Tm and a y A/y B ratio (the design variables to be optimized). This fixes the reactor inlet composition and temperature. 

Calculate the molar flowrate Fjn of the gas entering the reactor using an energy balance around the reactor given as follows  

The conversion is known, so the heat generated is known (— A)(0.12 kmol s). Thus, given the inlet temperature (Tiri) and the outlet temperatures (Tout = 500 K), the inlet flowrate to the reactor can be calculated, using the fact that the term F Y =a yf pi applies to both the inlet flow and the outlet flow and the inlet compositions are known. Once the inlet flowrate is known, the outlet molar flowrate Thmt is given by 

Then component balances are used to calculate the reactor exit compositions. 

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Refs. [i] Brett CMA, Oliveira Brett AM (1996) Electrochemistry. Oxford University Press, Oxford, chap 2 [ii] Kreysa G (1991) Electrochemical cell design and optimization procedures. Wiley-VCH... 

U Dok Hi, D.Ohms, R.Franke, K.Wiesener Qiem. Techn. 42 (1990) 294-297. K.Wiesener, D.Ohms, A.M6bius DECHEMA, Society of Qiemical Industry -Electrochemical Technology Group (London), European Federation of Qiemical Engineering (Working Party, 432 Event) Conference "Electrochemical Cell Design and Optimization Procedures", Bad Soden, 24-26.9.1990, Abstr., and publ. in DECHEMA-Monographien 123 (1991), 95-109. 

Wendt H, Rohland B (1991) Design principles of fuel cells and their components. In Kreysa G (ed) Electrochemical cell design and optimization procedures. DECHEMA Monographs, vol 123. VCH, Weinheim... 

The representation of trial fiinctions as linear combinations of fixed basis fiinctions is perhaps the most connnon approach used in variational calculations optimization of the coefficients is often said to be an application of tire linear variational principle. Altliough some very accurate work on small atoms (notably helium and lithium) has been based on complicated trial functions with several nonlinear parameters, attempts to extend tliese calculations to larger atoms and molecules quickly runs into fonnidable difficulties (not the least of which is how to choose the fomi of the trial fiinction). Basis set expansions like that given by equation (A1.1.113) are much simpler to design, and the procedures required to obtain the coefficients that minimize are all easily carried out by computers. 

Elompart et al. (2001), like Jozefaciuk et al. (2003), use a combined R D section (the preferred format in Analytical Chemistry, the journal that published this article). Their R D section describes both preliminary tests and optimization procedures. Results and discussion of the preliminary tests were presented in excerpt 4C results and discussion of the optimization procedures are presented in excerpt 5A. The optimization process used a factorial design in which five experimental parameters were systematically varied and tested to improve the saponification technique. These variables included the concentration of NaOH, the volume of NaOH, the extraction and stirring times, and the kind of SPME fiber used. 

The conventional procedure for introducing resilience in a HEN (or general process plant) is to use empirical overdesign. That is, a nominal or conservative basis is selected for designing and optimizing the HEN. Empirical safety factors based on past experience are applied to the equipment sizes and extra units are also often introduced. However, although this empirical procedure will in general add resilience and... 

Rossiter, A. P., and Douglas, J. M., Design and optimization of solids processes. Part 1. A hierarchical decision procedure for process synthesis of solids systems. Chem. Eng. Res. Des. 64, 175 (1986a). 

However, there is a remarkable disproportion between the three main areas occupied today by RC, namely hazards, process design/optimization and for monitoring the physico-chemical transformations. If there is an extensive activity in the field of hazards, often with little contribution to increased safety, probably less than 20% of the process development laboratories use calorimeters for process design and optimization very little interest is shown for the use of heat released as a tracer for physico-chemical transformations since RC is still barely used in synthesis laboratories where reactions and process procedures are initiated. 

Chemical and process engineering today is concerned with the understanding and development of systematic procedures for the design and optimal operation of chemical and process systems, ranging from micro-systems to industrial scale continuous and batch processes ( Mah, 1990 Thome, 1993 Savkovic-Stevanovic, 1995). 

A calibration set containing between 7-9 pg mL of Apt, 1-3 pg mL" of Ace-K, and 2-A pg niL of Sac was used. The designed and optimized training set of calibration was applied to the determination of three sweeteners of several synthetic mixtures. The method was also applied to commercial drinks and satisfactorily results were obtained. The procedures do not require any separation step for colorless sample (powder drink), but only an extraction step for colored beverages (powder and liquid) was used. The effect of cyclamate (CA) and ascorbic acid (AA) was also investigated. 

The discussion presented in the previous sections assumes that a process model is available. However, optimization of process operation is also possible when process models are not available. In this case, one must rely on available experimental process data and/or empirical modeling approaches. For instance, the process performance can be mapped within the experimental region of interest with the help of experimental design techniques. Experiments are performed in accordance with the proposed experimental design and empirical cubic models (or other types of empirical models) are fitted to the obtained experimental data. Then, the empirical models can be used to provide the searched optima. This type of experimental design-based optimization procedure was performed to optimize the operation of fermentors used for production of bacterial polyesters (177], as it is very difficult to develop a fundamental model for bacterial polymerizations. In this particular case, the medium composition was manipulated to allow for maximization of polymer production and rninirnization of the batch time. 

In future work the combination of the various methods for obtaining periodic states with both continuation and optimization procedures will be addressed. The final goal is a generic strategy for the analysis, design and optimization of cyclically operated processes. 

As this book serves as an introduction, we do not go into more complex examples whose formulation and solution procedure are out of the scope of this work. For those interested in the topic, we recommend specialized literature on systematic process design and optimization [14,15]. Furthermore, the literature is rich in papers on the design of different facilities of industrial interest such as hydrocarbon separation [16], hydrodealkylation (HDA) production process optimization [4], distillation columns sequence design, heat exchanger networks, power plants and IGCC modeling... 

As the subtitle indicates, the overriding intention of the authors has been to provide a practical guide to the design of electrolytic plant. We wanted to show that the procedures for the design and optimization of such a plant are essentially simple and can be performed by readers comparatively new to the electrochemical field. It was important to realize that electrochemical engineering should not be confused with applied electrochemistry but had to be based on the principles of chemical engineering. For this reason, reference is often made to standard chemical engineering texts. 

Summarizing, the proposed approach suggests the combination of the constructive and optimization methods to develop a tractable approach to tackle the complex process and control design problem. The construetive part provides the building of the controller, the means to assess the corresponding closed-loop dynamics, fundamental connections between process and control design, and a procedure to simplify the search of the optimal solution for the process and control design problem. 

Next, the particular experimental setup to prepare a set of calibration samples can be deployed following the procedures explained in Chapter 3 (experimental design and optimization). We have found it very useful to set a Plackett Burman design at each level of the analyte concentration but, of course, other possibilities exist. The important point here is to obtain a sufficiently large number of calibration samples so that any (reasonable) combination of concomitants and analyte that might appear in the problem samples has been considered previously in the cahbration. This is the general rule that you should model first what you want to predict afterwards ... 

It must be noted after a model is identified, a new set of experimental data is required to validate it in order to have confidence in its accuracy for the purpose or application it is established for. Establishing a valid model is one of the scientific and reliable tools researchers or practitioners use to undertake system analysis and design and optimize the system configuration and performance in order to establish and validate various concepts and ideas. To this end, significant research has been dedicated to the modeling and identification of EAP transducers. The procedure for model identification, which aims to obtain a mathematical model from input-output data, is depicted in Fig. 9. 

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