molten carbonate fuel cell

it is high temperature performing fuel cell.

1. Molten Carbonate Fuel Cell (MCFC) 1

2. Introduction MCFCs , or molten carbonate fuel cells , use molten mixture of carbonate salts: lithium, sodium, potassium carbonate as the electrolyte. The first MCFC was constructed in 1921 ,but it is developed in the year 1950 by Ketelaar and Broers . By 1960, they reported the first MCFC prototype. The cell operating temperature is high: between 873K-923K MCFCs are expected for high-efficiency power generation systems using hydrocarbon fuels, such as natural gas and coal gas. MCFCs are mainly used for stationary power generation in the 50 kW to 5 MW range. 2

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5. Arrangement of MCFC 5

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7. The electrode reactions for MCFCs are as follows, The overall reaction is a water producing reaction between oxygen and hydrogen, with the carbonate ions acting as intermediate agent to transfer oxide ion from cathode to anode. Electrons produced at the anode pass through an external circuit before flowing to the cathode, and thus electric power can be extracted . 7

8. Why carbonates are used? These carbonates are solid at room temperature , but they exhibit ion conductivity in a molten state at elevated temperatures and thus can be used as the electrolyte. Because of the high conductivity of molten carbonates, there is no need for a supporting electrolyte like those needed when using water or organic solvents as electrolytes. 8

9. Advantages of MCFCs Have high efficiency Do not need noble metal catalysts Have fast reaction kinetics (react quickly) Due to high temperature at which they operate, the fuels are converted to hydrogen within the fuel cell itself by a process called internal reforming , which reduce costs. 9

10. Disadvantages of MCFCs Having a liquid electrolyte, which introduces the handling of electrolyte. The known lifetime limiting phenomena are Corrosion of separator plate Electrolyte retention capacity Matrix cracking Contaminants 10

11. Comparison with other fuel cells 11

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13. Applications MCFCs are suitable for distributed generation and combined heat and power. It is used in large stationary power generation . Most of the fuel cells of megawatt capacity use MCFC as do large CHP* and CCP. These provide efficiency about 80% Molten Carbonate Fuel Cell (MCFC) has been developed by the European-funded MC WAP research project to be eventually used as an alternative power supply for ships . *Combined heat and power ( CHP ) systems, also known as cogeneration, generate electricity and useful thermal energy in a single, integrated system. 13

14. Conclusion Molten carbonate fuel cell (MCFC) has high potential for use as an energy converter of various fuels to electricity and heat. The MCFC is also a potential candidate for high temperature electrolysis , which is beneficial due to reduced overvoltage. The largest obstacles to a continued large scale introduction of MCFC onto the market of power generation are installation costs and life time issues related to performance degradation. A major concern is the presence of sulfur contaminants in fuel which shortens life time and causes the need of expensive gas cleaning installations for pre-treatment of the fuel. 14

15. References Viswanathan B,M.Aulice Scibioh , Fuel Cells-Principles and Applications, Universities Press,Hyderabad , India, 2006 Kouichi Takizawa, Molten Carbonate Fuel Cells , Energy Carriers And Conversion Systems – Vol. II,Tokyo Electric Power Company, Japan. http://www.eolss.net/sample-chapters/c08/E3-13-10-06.pdf http://www.fuelcell.co.uk/molten-carbonate-fuel-cells/ http://www.idconline.com/technical_references/pdfs/chemical_engineering/Molten_carbonate_fuel_cells.pdf http://www.youris.com/mobility/marine_transport/molten_carbonate_fuel_cells_an_alternative_and_cleaner_power_supply_for_ships.kl#ixzz53CR2NITl 15