A Combinatorial Optimization Problem to Control a Solar Reactor

AbstractIn the scope of the HYDROSOL project and the consecutive HYDROSOL-2 project, both funded by the EC, a pilot plant was installed in the SSPS solar tower at CIEMAT–Plataforma Solar de Almería (PSA), Spain, for producing solar hydrogen from water using a ferrite-based redox technology. It consists of two reactors where hydrogen and oxygen production cycles are alternated for quasi-continuous hydrogen production. In the first step (water splitting), an exothermic reaction takes place at an operating temperature of 800°C. The second step (thermal reduction) is an endothermic reaction which requires an operating temperature of 1200°C.The HYDROSOL-3D project focuses on the next step towards commercialisation, carrying out all the activities necessary to prepare the erection of a 1 MW solar demonstration plant. HYDROSOL-3D concerns, for example, the implementation of the control strategies and algorithms in a specific process control system for the plant. This paper summarises the work carried out by CIEMAT-PSA to develop a control strategy using a dynamic model of a solar hydrogen production plant which was developed based on previous experiments with this pilot plant. This model includes both a solar field and a processing plant and is able to simulate the concentrated solar power received by the reactors and the thermal and chemical reactor behaviour. Particular attention is given to the control strategy for controlling the operating temperatures in the solar hydrogen reactor, considering a new algorithm to choose the heliostats which must be focused