(158k) A Fuel Cell Module for a Chemical Process Control Course

Alternative energy research and development is once again receiving well-deserved attention, with fuel cell technology playing an important role in a so-called hydrogen economy of the future. Fuel cells offer the potential for a higher efficiency source of low pollution emission energy. There are several areas of key importance within fuel cell systems engineering, including catalytic reformer modeling and control. Reforming is the process of converting hydrocarbon feedstocks into hydrogen rich streams that are fed into the anode of PEM fuel cell stacks.

Educators are being encouraged to make chemical engineering courses more relevant and interesting to students, by incorporating more motivating examples. This presentation details a novel fuel cell case study appropriate for use as a “capstone” project in Chemical Process Control courses. The case study focuses on the fuel cell reformer, and develops a multivariable system that has challenging dynamic behavior. The measured outputs of the system are burner and reformer outlet temperatures, and they are controlled by the manipulated inputs of excess air ratio and flowrate of methane to the burner. The corresponding multivariable transfer function matrix contains both first order responses and lead-lag responses. Also included in the model is a disturbance input designed to mimic the sintering of catalyst particles, which is known to affect the performance of reformers. The work details the complete control design process, from modeling the system with open-loop step tests to the final multivariable controller design. The input-output pairings are determined on the basis of a relative gain array (RGA) analysis, and the controllers are designed using internal model based PID strategies. The directional sensitivity and operability of the system is analyzed through singular value decomposition (SVD), and the corresponding feasible operating regions are determined. The end result is the development of a complete fuel cell module that can be used in Chemical Process Control courses.