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Control design and dynamic simulation of an HMR pre-combustion power cycle based on economic measures

Zhao, Lei, Michelsen, Finn Are, Foss, Bjarne
Energy 2013 v.51 pp. 171-183
carbon dioxide, combustion, controllers, dynamic models, electric power, energy, heat, hydrogen
This paper studies dynamic behaviour and control design of a hydrogen membrane reforming (HMR) power cycle based on economic measures. The HMR power cycle is a novel pre-combustion capture power cycle for electrical power production which incurs less of an energy penalty than current post combustion technologies. However, the HMR power cycle consists of a novel reformer and complex heat integration. For this type of power cycle to be competitive, it is important to have a thorough understanding of the system dynamics including robust control design which secures reasonable rejection of all important disturbances and tracking of desired outputs like load and CO₂ capture flow rates. First, a new dynamic model of the HMR power cycle aimed at control design is developed based on first principles. It is further validated against existing knowledge. Dynamic behaviour of the critical components as well as the whole plant is investigated based on the model. Then, control structures of the power cycle are designed by a systematic approach. To determine the control structures, an economic objective is chosen, the degrees of freedoms and constraints are found, and appropriate disturbances are assumed. To handle the constraints systematically, model predictive control (MPC) is used in some parts of the power cycle. Finally, the control structures with well-tuned MPC controllers, PI controllers and feedforward controllers are simulated and evaluated.