APC 400kW1MW User Manual download pdf (Page 17)

2.2.2 Molten Carbonate Fuel Cell

A molten carbonate fuel cell contains an electrolyte made of lithium-potassium carbonate

salts. These salts are heated to about 1,200°F (650°C), which causes them to melt into a

molten state that is able to conduct ions [22, para 2]. Because these fuel cells operate at such

high temperatures, non-precious metals are used. The catalyst and cathode are made of nickel

and nickel-oxide, respectively. Because they are made of metallic stack components that are

suitable for common manufacturing methods, the initial investment costs of MCFCs are reduced

[6, para 12; 23, p. 11].

The MCFC’s high operating temperature enables fuel reforming to be done internally,

making it a good candidate for heat recovery and steam generation. They are able to produce

waste heat at temperatures ranging from 750°F to 840°F (400° to 450°C) [23, p. 11; 6, para 14].

MCFCs are primarily used in industrial and large commercial applications with a typical power

output range of 250kW to 2000kW [12, p. 6].

MCFCs are able to reach considerably higher electrical efficiencies compared to the

other fuel cell types. Their electrical generation efficiency is 50%. and, when used in CHP

applications, efficiencies can reach 90%. The efficiencies are independent of the load and

remain high throughout the lifetime of the MCFC [23, p. 11-12; 22, para. 4-5].

MCFCs have a few notable advantages over the PAFC. With higher efficiencies,

MCFCs are able to offer significant operating cost reductions over phosphoric acid technology.

The less expensive nickel catalyst compared to the pricey platinum catalyst of the PAFC adds to

the cost difference of these two fuel cells [23, p. 11; 22, para 4-5].

In case there are concerns with interruptions in the gas grid, MTU CFC Solutions has

tested the reaction of their HotModule MCFC when it is switched to a liquid fuel supply, such as

methanol and liquefied petroleum gas. Tests showed that the HotModule provided continuous

power while switching the fuel supply from natural gas to methanol, as shown in Figure 2-4.

These test results prove that a facility can be independent from a single fuel provider and

protected from interruptions in the gas grid [23, p. 13].

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APC 400kW1MW User Manual Page 17