Introduction to the MCFC

The MCFC (Doyon etal., 2003) can use natural gas directly via medium-temperature anode reform, and therefore does not require a commercial and cheap hydrogen source. The MCFC is incomplete in the sense of circulators as covered in the first three chapters and Appendix A. 

In Japan, IHI, Mitsubishi and Hitachi are prominent in the MCFC business. Italy (Ansaldo Research) and the Netherlands (ECN-InDEC) are major players in Europe. Korea, via the Korea Institute of Science 

Fuel Cells, Engines and Hydrogen - An Exergy Approach Frederick J. Barclay 2006 John Wiley 6c Sons, Ltd 

At equilibrium there is zero electric current, and the motor terminal potential difference is the same as that of the cell. The CO3- ion circulation is zero. Inside the cell, ion migration in the potential gradient is matched by counter migration in the concentration gradient. (Hydrogen Fuel) 

With methane fuel and a reformer, the port-manteau equation, which embraces reform and shift reactions is  

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The various types of fuel cells are at somewhat different stages in the technology cycle the MCFC is ready for market introduction but faces the typical problem of a new technology, i.e., is expensive because of the lack of economies of scale for its production and the lower cost of its technical rivals (engine-driven co-generation and microturbines). From the technical point of view, the phase of euphoria has almost passed for PEMs and SOFCs and further R D activities are necessary for these two types to match the technical performance of their competitors or the necessary cost level for fuel cells to be technologically and economically ripe for the market. Only the DMFC has reached a standard that allows its use in niche markets, like caravans or yachts, despite poor efficiency levels. 

In this chapter, we focus on the MCFC with internal reforming. After a brief technical introduction of this type of fuel cell, a model is presented that describes the interaction of the reforming reaction and the electrochemical oxidation reaction inside the MCFC with a set of only two ordinary differential equations (ODE) and some algebraic equations (AE). A diagram is introduced which allows the simulation results to be displayed in an easily interpretable way. Finally, the usefulness of the model and its accompanying diagram are demonstrated in several applications. 

After two decades of intensive fuel cell research and development, some of the described technologies have come close to the market. This is particularly the case for the PEFC technology developed worldwide by automotive industry. Market introduction is planned, according to various sources, by the year 2015. However, still issues of cost and reliability remain and provide ample space for further research. Unfortunately, other technologies, e.g., the SOFC and MCFC technology, have recently seen some setbacks, due to the fact that some longstanding prominent advocates of fuel cell development have decided not to continue their effort (e.g., SOFC by Siemens, MCFC by Tognum (formerly MCFC solutions), others). 

The high operative temperatures and the electrolyte chanistry can be responsible of some issues. The high temperature requires significant time to reach operating conditions and responds slowly to changing power demands. These characteristics rnake MCFCs more suitable for constant power applications. The carbonate electrolyte can also cause electrode corrosion problems [92, 93], Furthermore, since CO2 is consumed at the anode and transferred to the cathode, introduction of CO2 and its control in air stream becomes an issue for achieving optimum performance that is not present in any other fuel cell [13]. 

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