C and 1 atm. Fuel

Figure 6-15 Average Cell Voltage of a 0.37m 2 kW Internally Reformed MCFC Stack at 650°C and 1 atm. Fuel, 100% CH4, Oxidant, 12% C02/9% 02/77% N2 (12)...

Figure 6-5 Voltage and Power Output of a 1.0/m 19 cell MCFC Stack after 960 Hours at 965 °C and 1 atm, Fuel Utilization, 75 percent (50)...

Table 1. Flammability limits of fuel gases and vapors in air at 25°C and 1 atm...

The data presented in Table El are for fuel gases and vapors and are taken almost exclusively from Zabetakis. [IJS Bur. Mines Bull. 627 (1965)]. The conditions are for the fuel-air mixture at 25°C and 1 atm unless otherwise specified. As noted in the text, most fuels have a rich limit at approximately = 3.3 and a lean limit at approximately = 0.5. The fuels which vary most from the rich limit are those that are either very tightly bound as ammonia is or which can decompose as hydrazine or any monopropellant does. Additional sources of flammability limit data can be found in the Ignition Handbook by Babrauskas (Fire Science Publishers, Issaquah, WA, 2003) and from Kuchta [1/5 Bur. Mines Bull. 680 (1985)]. 

Figure 6-12 CH4 Conversion as a Function of Fuel Utilization in a DIR Fuel Cell (MCFC at 650"C and 1 atm, steam/carbon ratio = 2.0, >99% methane conversion achieved... 

Once again, the reference states for determination of the specific enthalpies in this equation must be those used to determine the value of A//°. If the heats of combustion in Table B.l are used, the reference states would be the fuel, combustion products (including liquid water), and inert species at 25 C and 1 atm. The fuel would be in whichever state (solid, liquid, or gas) Table B.l specifies. 

The fuel heating value is the total amount of energy that can be liberated by combustion of a fuel. The heating value may be normalized by mass, moles, or volume accordingly, it will have units of kj/kg, J/mol, or J/Nm. Customary units include Btu/lbm, Btu/lbmol, and Btu/scf. In the case of volume, some standard temperature and pressure must be chosen, such as 25°C and 1 atm. Two examples of unit volumes referenced to such conditions are the normal meter cubed (Nm ) and the standard cubic foot (scf). 

Used to denote heating value of fuel gas the temperature and pressure should be stated usually 0 C and 1 atm in scientific work. The U.S. natural gas industry uses. slaridard conditions of 5D°F and 14T7 lb 5i ... 

Electrochemical Reactor Design and Configurations, Fig. 3 Contributions of component overpotentials to a fuel cell polarization curve (a) simulated polarization curve for water-saturated H2 and air at 80 °C and 1 atm. The curves are (—) cell potential E, (— —) reversible potential Erev, ( ) transport-limited overpotential r)n, (— —) ohmic resistive overpotential r), and (— —)... 

Therefore, the reversible (theoretieal) hydrogen/oxygen fuel eell potential is 1.229 V at standard state (25 °C and 1 atm). This value varies with temperature. 

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