The operation of a chemical process plant has become more complex with the addition of process integration and intensification. A greater emphasis on producing goods with the lowest product variability in the safest manner possible and stringent environmental regulation limiting the quantity of effluent release have all put more constraints on the physical and economic performance of the chemical plant. The performance of a plant is quantified by the ability of the process system to achieve its objectives, which is governed by its process design and control. The conventional approach to process design and control selection starts sequentially by proposing a process flowsheet for the plant. The selection criteria for a flowsheet are normally based only on its environmental impact and economic merits. It is after a process flowsheet is deemed financially suitable that process control development commences. However, a more integrated approach to process design and control stage may thus lead to a plant that has better achievable performance. The aim of this project is to provide a new approach to quantitative dynamic controllability analysis for integration of process design and control by using the concept of passivity and passive systems. Passivity is an input/output property of processes. Passive processes are stable and minimum phase and therefore very easy to control. For a given process, its shortage of passivity, which reflects destabilizing effects of factors such as time delays and Right-Half Plane (RHP) zeros, can be used to indicate its controllability. The project focuses in developing the proposed controllability analysis by combining the idea of passivity and IMC invertibility, which is then formulated into an optimization problem that can be solved by either using Semi-Definite Programming or Non-Linear Optimization. The achievable performance of the plant is quantified in terms of the sensitivity function of the open-loop process. The selection of a process from four different heat-integrated distillation column schemes was used as a case study and the result had clearly shown that the passivity-based controllability analysis was able to select a process based on the plant achievable performance under the constraint of passivity and design parameters.
| Identifer | oai:union.ndltd.org:ADTP/215408 |
| Date | January 2005 |
| Creators | Suryodipuro, Andika Diwaji, School of Chemical Engineering & Industrial Chemistry, UNSW |
| Publisher | Awarded by:University of New South Wales. School of Chemical Engineering and Industrial Chemistry |
| Source Sets | Australiasian Digital Theses Program |
| Language | English |
| Detected Language | English |
| Rights | Copyright Andika Diwaji Suryodipuro, http://unsworks.unsw.edu.au/copyright |
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