MCFC - Molten-Carbonate Fuel Cells

Introduction

Molten Carbonate Fuel Cells (MCFC) is in the class of high-temperature fuel cells. The higher functioning temperature allows them to use natural gas exactly without the need for a fuel processor and have furthermore been utilized with low-Btu fuel gas from developed processes and other causes and fuels. Developed in the mid 1960s, improvements have been made in fabrication procedures, presentation and endurance.

MCFCs work quite distinctly from other fuel cells. These cells use an electrolyte consist of a molten mixture of carbonate salts. Two mixtures are usually used theses days: lithium carbonate and potassium carbonate, or lithium carbonate and sodium carbonate. To dissolve the carbonate salts and get high ion mobility through the electrolyte, MCFCs operate at high temperatures (650ºC).

Discussion and Analysis

Molten Carbonate Fuel Cell Applications

Molten carbonate fuel cells demand such high functioning temperatures that most applications for this kind of cell are restricted to large, stationary power plants. Yet consumers might take advantage from this kind of cell, even if they never see it in their homes. The high functioning temperature opens the opportunity of utilizing waste heat to make vapor for space heating system, industrial processing, or in a steam turbine to develop more electricity. Many modern gas-fired power plants exploit this type of system, called cogeneration (Linden, 25).

Performance

Molten-carbonate fuel cells with two kinds of alkali carbonate mixture as the electrolyte have been operated. The resulting cell performances have been compared to optimize the composition of each carbonate mixture. One electrolyte type is a mixture of the high lithium eutectic ((Li0.62K0.38)2CO3) and an alkaline-earth carbonate, while the other is a mixture of the lithium-sodium eutectic ((Li0.52Na0.48)2CO3) and an alkaline-earth carbonate. Additions of CaCO3, SrCO3 and BaCO3 have been used. A small amount of each alkaline-earth carbonate to both eutectics does not affect the cell performance. On the other hand, larger amounts reduce the cell performance (Linden, 25). The needed content of each additive to supply optimum cell performance depends on both the additive itself and the host eutectic. The temperature dependence of cell presentation in the occurrence of the distinct additives has also been investigated. There is little difference between the behavior of ((Li0.62K0.38K0.38)2---Ca) CO3, ((Li0.62K0.38)2---Ba) CO3 and ((Li0.52Na0.48)2---Ca) CO3. By contrast, high temperature dependence was found for ((Li0.62K0.38)2---Sr) CO3, ((Li0.52Na0.48)2---Sr) CO3 and ((Li0.52Na0.48)2---Ba) CO3.

Molten Carbonate Fuel Cell conceive and Operation

Molten Carbonate Fuel Cells use a molten carbonate saline mixture as its electrolyte. The composition of the electrolyte varies, but generally comprises of lithium carbonate and potassium carbonate.

The Molten Carbonate Fuel Cell reactions that take place are:

The anode method involves a answer between hydrogen and carbonate ions (CO3=) from the electrolyte which makes water and carbon dioxide (CO2) while issuing electrons to the anode. The cathode process combines oxygen and CO2 from the oxidant stream with electrons from the cathode to produce carbonate ions which go in the electrolyte. The need for CO2 in the oxidant stream requires a system for collecting CO2 from the anode exhaust and mixing it with the cathode feed ...