This paper describes and illustrates the application of a methodology for thermo‐economic design and optimisation of fuel cell systems. This methodology combines the use of process simulation and process integration techniques to compute thermo‐economic performances of fuel cell systems that will be used in a multi‐objective optimisation framework. The method allows the generation of integrated fuel cell system configurations and their corresponding optimal operating conditions. It should be used as a preliminary design methodology, allowing the identification of promising system configurations, which would be further analysed. The methodology and the thermo‐economic models are described and demonstrated for the design of PEMFC hybrid systems, combining fuel cell and gas turbine technologies.

A system model including a PEM fuel cell and its fuel preparation process has been developed. The goal was to investigate the process configurations to identify the optimal operating conditions and the optimal process structure of the system by applying modelling and energy integration techniques. The Ballard&Alstom's system has been considered as the initial process structure in order to define the major equipments to be considered. A simulation model using a commercial chemical process simulation software (BELSIM-VALI) has been developed. The model includes a catalytic reforming, CO-removal (Shift) and preferential oxidation for the fuel processing as well as a PEM fuel cell model and the combustion chain. The equation solver approach used by this software tool offered a real flexibility for the process synthesis approach that has been applied. The energy and the material flows obtained by simulation have been used to compute the process composite curves of the system. This has been used to identify the best heat exchange opportunities and to define the optimal operating conditions of the reforming system that provide the best overall efficiency for the balance of plant.The system has been studied according to the energy efficiency, the exergy efficiency as well as thermoeconomical parameters in the context of the combined production of heat and power.By improving the energy integration of the system, the efficiency can be raised from 35% for the reference system to 48%. To illustrate the results that will be presented, the following charts show, for a given reforming temperature, the influence of steam to carbon ratio on the system efficiency for two different configurations as well as the corresponding composite curves resulting for the balanced system.

A method that combines process modelling and process integration techniques has been developed to tackle the design of complex integrated systems like fuel cell systems. This method uses the equations of the composite curves as constraints to model the ideal heat exchanger network and the corresponding utility system. When combined with the use of process modelling techniques, this method allows to synthesize optimized fuel cell integrated systems with high efficiency and that integrates the technological design constraints.