Plant-wide Modeling, Design Consideration, and Practical Hierarchical Control Strategy Considering Key Variable Integral Characteristics for an Industrial Alkaline Water Electrolyzer Plant

The alkaline water electrolysis (AEL) system stands out in clean hydrogen production and is commercially available owing to its high technology readiness level. Despite the current progress, including modeling and control made for the critical component electrolyzer stack, in-depth research on the plant-wide model establishment and control strategy for the plant is still limited and should be investigated to realize the optimal operation of the whole AEL plant. To address this problem, a complete industrial AEL plant composed of multiple components, including the electric power supply and the auxiliary systems for the balance of the plant, is built up. Moreover, the manipulated variables and the controlled ones of the plant are determined, and the hierarchical control structure is proposed to maximize hydrogen production based on the established AEL plant model. The upper real-time optimization (RTO) layer in the structure calculates the economic decision in real time and then sends the set points of the critical variables to the lower supervisory layer. Proportional-integral-derivative (PID) and integral dynamic matrix control algorithms are utilized jointly in the lower layer, considering the dynamic characteristics of the AEL plant, to track the controlled variables to the optimal setpoints and reduce the computation burden as much as possible. Simulation on setpoint tracking is performed to verify the effectiveness of the proposed strategy in comparison with the traditional PID controller.