Flowsheeting methodology

We have used the scoping flowsheet methodology to calculate Level 1 and Level 2 efficiencies for the CU-SO4, Zn-SO4, and CuCl cycles, as well as for a new cycle, Mg-Cl [1, 4]. All are hybrid cycles i.e., they contain an electrochemical reaction. The methodology is illustrated in detail for the CU-SO4 cycle. Only the results are presented for the other cycles evaluated. 

Table 3. Summary of the efficiency calculations for the candidate cycles evaluated with the scoping flowsheet methodology...

We developed a scoping flowsheet methodology to evaluate the potential of alternative cycles. 

The methodology for proposing flowsheet modifications to ensure the existence of an ASVS is described in this section. 

The second example that is used to illustrate the design methodologies is a modification to the EDTA problem as follows. The structure of the flowsheet is exactly the same as the one presented in Section IV. The only change to the problem is the statement that sulfuric acid and formaldehyde should not be allowed to come into contact with each other. 

Level 7 Process-Control System. The key issues of process dynamics and control, namely fresh feed policy and stability in operation of the reaction/separation/ recycle system, are solved at Level 3. Consequently, the implementation of a process-control system may be realized without affecting the basic flowsheet structure, but taking into account fundamental process control principles, as proposed in the methodology developed by Luyben and Tyreus [20]. 

The hierarchical approach is a simple but powerful methodology for the development of process flowsheets. It consists of a top-down analysis organized as clearly defined sequence of tasks aggregated in levels. Each level handles a fundamental conceptual problem input/output structure, reactor design, structure of separa-... 

M. H. Locke, and A. W. Westerberg The Ascend-II System—A Flowsheeting Application of Successive Quadratic Programming Methodology, Comput. Chem. Eng., v. 7, p. 615 (1983). 

More recant efforts to develop computer-aided process synthesis methodologies can be cbeincterized as either sequential modular, simultaneous modular, or equation oriented, Sequeatial-modular approaches are ben for steady-state simulation where process inputs are defined and process para met ara ate available. The best feature of sequential-modular approaches is that they are flowsheet oriented, bot they are not as flexible as the other methodologies in parfonuing design and optimization tasks.39... 

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