Multi-Fuel Reforming and Fuel Cell Systems for Aviation Applications: The Role of Bio-Diesel and its Synergy with Global Interests

The rising cost of fuel prices, in part due to the perception of diminishing supplies of common fuelstocks, as well as worldwide attention to reducing emissions has pushed the need to explore the use of many alternative fuels. The aviation industry has been under recent scrutiny due to its contribution of greenhouse gas emissions (GHG). Current contribution of GHG by airplanes is relatively small, 2% of the total GHG emissions, but world air traffic is anticipated to continue to grow and may have a corresponding increase in emissions. Both commercial and government aviation sectors have efforts to seek ways to lower fuel consumption through efficiency and reduce emissions. Development of a suitable alternative fuel that can be seamlessly used in place of conventional jet fuel is desirable. A strategy to enable this goal is to be fuel flexible; utilizing an array of fuels from bio-diesel to current jet fuel. One pathway to this fuel-flexibility is to start with bio-diesel and its next generation of alternative fuels. The use of hybrid fuel cell systems operating on alternative fuels such as bio-diesel in ground support equipment and eventual use in aircraft can enhance energy efficiency while reducing emissions. Bio-diesel is free of sulfur, allowing the development of the core fuel processing and fuel cell components of the system. Bio-diesel is also a good starting point towards fuel-flexible reforming systems that can work with other traditional and alternative fuels with only minimal changes in the operating condition of the system.

In this paper, we will speak to the development of a 1 kW fuel cell/fuel processing system operating on bio-diesel. The system consists of a fuel-flexible fuel process for the conversion of bio-diesel into hydrogen, a fuel cell, and a unique modular power and control architecture that is adaptable to the potential use of other various types of fuels. We will discuss a prototype fuel cell system utilizing bio-diesel, and explain our approach for achieving larger power ranges and fuel flexibility, including the incorporation of desulphurization technology into the existing process. We will also describe some of the larger advantages of our approach in helping the aviation sector with using cleaner and readily-available alternative fuel sources.