Thermodynamic Analysis of a Molten Carbonate Fuel Cell Systems Using Waste Heat Derived Fuel

The increasing energy demand along with the growing concern for the environmental issues requires a significant research effort on the development of energy systems with high efficiency and low environmental impact. The use of waste derived fuel in fuel cell systems provides the benefits of high efficiency and very low polluting emissions as well as an effective way of waste disposal. In the present work an investigation of the potential use of waste derived fuel gas in Molten Carbonate fuel cell systems has been performed. A detailed description of the simulation model developed by the authors with the Aspen Plus thermodynamic flow sheet code is presented. The basic configuration of the plant uses pure methane as fuel. An improved plant configuration has been proposed which allows an optimal exploitation of all the thermal streams giving as an output high electrical yield and heat at high temperature. The plant is then adapted to different gas blends as fuel: landfill gas and gas from the gasification of MSW (Municipal Solid Waste). The analysis is focused on the comparison between different fuel gases plants in terms of efficiency, feasibility and process requirements. Depending on the fuel characteristics, different solutions are applied to the plant in order to achieve optimal exploitation of the thermal streams. A general conclusion is that the use of low BTU gas results in an efficient and environmentally sound power generation but leads to a reduction of the plant net power output especially in the case of using gas derived from existing gasification plants. A consistent research activity is required to identify waste derived fuel processing systems that can yield gases which allow an optimal exploitation in fuel cell systems