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This research is a preliminary design study relating to the importation of liquefied natural gas (LNG) in the United Kingdom, focusing on the process design, simulation and control of a flexible LNG reception terminal. The primary operating objective of the proposed LNG reception terminal is to accept a wide variety of LNG feedstocks, and to continuously produce output with consistent specifications. This requirement to provide "feedstock flexibility" was the major influence in the development of this research. The process design was derived from the application of selection criteria to assess the impact of feedstock flexibility on process unit performance. The subsequent dynamic simulation had to represent multiple operating conditions and feedstock changeovers for a multicomponent system. This required the incorporation of an interactive physical properties database and the adoption of a pseudo-binary distillation column model in the simulation. Regulatory control loops were developed and tuned to provide stable operation for all the plant's operating conditions. In order to assess the impact of multiple feedstock conditions, control system performance was evaluated for disturbance rejection and control valve action. A changeover mechanism was developed which enabled successful dynamic simulation of feedstock changeovers. The simulation also identified significant interactions between certain process units in the flowsheet. In conclusion, the primary objective of the supervisory control system would be management of these interactions as opposed to maintenance of product specifications. This work has provided a preliminary flowsheet and a design tool for process and control studies, for a flexible LNG reception terminal. These will enable the design engineer to investigate a range of changes to the process design and to assess their implications for the plant's overall dynamic behaviour.

In the promotion and development of renewable energy systems, control engineering is one area which can directly affect the overall system performance and economics and thus help to make renewable energies more attractive and popular. For cost effectiveness, ideally the renewable energy industry requires a control design technique which is very effective yet simple with methods that are transparent enough to allow implementation by non-control engineers. The objective of this thesis is to determine if Model Based Predictive Control (MBPC) is a suitable control technique for use by the renewable energy industry. MBPC is chosen as it uses simple and fairly transparent methods yet claims to be powerful and can deal with issues, such as non linearities and controller constraints, which are important in renewable energy systems. MBPC is applied to a solar power parabolic trough system and a variable speed wind turbine to enable the general applicability of MBPC to renewable energy systems to be tested and the possible benefits to the industry to be assessed. Also by applying the MBPC technique to these two strongly contrasting systems much experience is gained about the MBPC technique itself, and its strengths and weaknesses and ease of application are assessed. The investigation into the performance of Model Based Predictive Control and in particular its application in the renewable energy industry leads to two contrasting conclusions. For simple systems with non-demanding dynamics and having a good model of the system, MBPC provides a very good and effective solution. However for more demanding systems with complex dynamics and strong non-linearities, a basic MBPC controller, applied by a non-control engineer, cannot be recommended.

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