Optimisation of a fuel cell system using process integration techniques

A model of a system including a proton exchange membrane (PEM) fuel cell and its fuel processing section 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 modeling and process integration techniques. A simulation model using commercial chemical process simulation software (BELSIM-VALI) has been developed. The model includes a steam methane reforming (SMR), a water gas shift (WGS) and a preferential oxidation (PROX) for the fuel processing feeding a proton exchange membrane cell stack (PEM) and a post-combustion unit. 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 in order to provide the best overall efficiency considering the balance of plant. By improving the energy integration of the system and by using optimisation of operating conditions, the efficiency can be raised from 35% for the reference system to up 49% in the optimized design. This is obtained both by process configuration modifications and by optimizing operating set-points. The model developed has been used for sensitivity analysis and will serve as a basis for further process design including the optimal structure determination and the thermo-economic optimisation.

Performance evolution and modeling of PEM fuel cell systems

Nicolas Roggo

In the context of climate change mitigation, different alternatives to reduce the atmospheric CO2 emissions are; increasing the efficiency, switching to renewable resource and reduce emissions from fossil resources by CO2 capture and storage (CCS) . Hydrogen is considered as potential alternative to cover the energy needs by using it as a fuel in internal combustion engines or fuel cells, or as chemical source. In proton exchange membrane (PEM) fuel cells, also known as polymer exchange membrane fuel cells, pure hydrogen fuelis combined with the oxygen from the atmosphere to produce water, heat and electricity. Many research has been done in recent years on fuel cell systems leading to higher efficiencies. The performance is influenced by the membrane properties, the catalysts, the number of cells and the operating conditions. For studying the performance of fuel cell systems process modeling is a well-known approach. Here the evolution of fuel cell efficiency, especially of PEMFC is studied within the aim of updating previously developed PEMFC process models to integrate them with different hydrogen production processes using fossil and renewable resources in order to assess the competitiveness on the energy market.

2012

A Methodology for Thermo-Economic Modeling and Optimization of SOFC Systems

Nordahl Autissier, François Maréchal, Francesca Palazzi, Jan Van Herle

Fuel cell systems integrate the fuel cell technology with fuel processing and post processing. A thermo-economic optimization method has been developed to systematically generate the most attractive configurations of the integrated system. In the developed methodology, the energy flows are computed using conventional process simulation software. The system is integrated using the pinch based methods that rely on optimization techniques. This defines the minimum of energy required and sets the basis to design the ideal heat exchanger network. A thermo-economic method is then used to compute the integrated system performances, sizes and costs. This allows performing the optimization of the system with regard to two objectives: minimize the specific cost and maximize the efficiency. The multi-objective optimization strategy identifies interesting system configurations and their performance. This method will be used as a support for decision makers when designing a new system. In this paper, the methodology is applied to study the integration of a Solid Oxide Fuel Cell system.

2005

Optimization and dynamic responses of an integrated fuel cell and battery system for an 800 kW ferry: A case study

Martin Daniel Gay, Hossein Pourrahmani, Jan Van Herle

The recent targets by different countries to stop the sales or registrations of internal combustion engines (ICE) have led to the further development of battery and fuel cell technologies to provide power for different applications. The main aim of this study is to evaluate the possibility of using an integrated Lithium-Ion battery and proton exchange membrane fuel cell (PEMFC) as the prime mover for a case study of a 800 kW ferry with a total length of 50.8 m to transport 780 passengers for a distance of 24 km in 70 min. Accounting for five types of Lithium-Ion batteries and different numbers of PEMFCs, twenty-five scenarios are suggested based on a quasi-static model. To perform the optimization, the Performance Criterion of the Fuel cell-Battery integrated systems (PCFB) is introduced to include the effects of the sizes, weights, costs, hydrogen consumption, efficiency, and power in addition to the number of fuel cells and the battery capacity. Results indicate that the maximum PCFB value of 10.755 (1/kg(2)m(3)

) can be obtained once the overall size, weight, efficiency, hydrogen consumption, and cost of the system are 18 m(3), 11160 kg, 49.25%, 33.6 kg, and 119.58 k

ELSEVIER2022

Optimization and dynamic responses of an integrated fuel cell and battery system for an 800 kW ferry: A case study

Martin Daniel Gay, Hossein Pourrahmani, Jan Van Herle

) can be obtained once the overall size, weight, efficiency, hydrogen consumption, and cost of the system are 18 m(3), 11160 kg, 49.25%, 33.6 kg, and 119.58 k

ELSEVIER2022