Methane, as fuel

Fundamental investigations of soot growth and oxidation were performed by many researchers in both diffusion and premixed flames with ethene and methane as fuels (see, e.g., Santoro and Shaddix, 2002 Schulz et al., 2006). 

The stack delivered 9.2 kWei in operation with hydrogen and 5.4 kWei with methane as fuel gas [1]. Whilst a small fraction of hydrogen was added to... 

Dimensional requirements for critical components for DMFC devices using methane as fuel are strictly dependent on the electrical power-generating capacity of the cell. DMFC cell designers recommend the typical dimensions for various components as shown in Table 3.12. 

The synthesis gas route also consumes methane as fuel in contrast to the direct route. The fuel is converted into carbon dioxide which represents a loss. However, Figure 15 illustrates that the two routes have almost the same CO2 production which may be taken as a rough measure of the process efficiency. 

As it can be seen, low-temperature and high-temperature fuel cells can be distinguished. Low-temperature fuel cells are the Alkaline Fuel Cell (AFC), the Polymer Electrolyte Fuel Cell (PEMFC), and the Phosphoric Acid Fuel Cell (PAFC). The high-temperature fuel cells operate in the temperatures region from 500 to 1000 °C two different types have been developed the Molten Carbonate Fuel Cell (MCFC) and the Solid Oxide Fuel Cell (SOFC). They have the ability of using methane as fuel and thus present high inherent generation efficiency (45-60 % for common fuels such as natural gas, 90 % with heat recovery [3]). 

Fig. 5.50 SOFC-GT hybrid system where the combustion chamber has been replaced by a fuel cell. The system configuration is labeled Case 1 (for hydrogen as fuel) and Case 2 (for methane as fuel)...

When coal is coked at a temperature of approximately 1000°C, about 70—75% of the product is coke. Nearly 20% of the product is a light gas, mostiy methane and hydrogen, that typically is used as fuel to heat the ovens. Coal tars amount to about 4% of the product and light oil or naphtha is about 1%. Ammonia is recovered in an amount equal to about 0.3% of the feed coal. The ammonia is usually converted to ammonium sulfate and sold as a fertilizer. Littie or no ammonia [7664-41-7] is produced inlow temperature carbonization (3). 

Landfill G as Recovery. This process has emerged from the need to better manage landfill operations. Landfill gas is produced naturally anaerobic bacteria convert the disposed organic matter into methane, carbon monoxide, and other gases. The quantity of methane gas is substantial and could be utilized as fuel, but generally is not. Most of the methane simply leaks into the surrounding atmosphere. 

Removal of volatile matter to about 0.5 wt% can be accomplished by calcming in a rotary kiln, rotary hearth, or vertical shaft calcmer All of these processes heat green coke to temperatures in excess of 1000°C where shrinkage and subsequent densification take place. The volatile components are comprised primarily of methane, ethane, hydrogen, and hydi ogen sulfide gases which can be employed as fuel for process heat. 

A natural gas having the volumetric composition of 90% methane, 8% ethane, and 2% nitrogen at 1 atm and 25°C is used as fuel in a power plant. To ensure complete combustion 75% excess air is also supplied at 1 atm and 25°C. Calculate (i) the lower and higher heating values of the fuel at 25°C and (ii) the theoretical maximum temperature in the boiler assuming adiabatic operation and gaseous state for all the products. 

As a constituent of natural gas, ethane is normally burned with methane as a fuel gas. Ethane s relation with petrochemicals is mainly through its cracking to ethylene. Ethylene is the largest end use of ethane in the U.S. while it is only 5% in Western Europe. Chapter 3 discusses steam cracking of ethane. 

We are so used to free air that we do not think of oxygen as an important chemical. For example, we buy natural gas (mostly methane) as a fuel and burn it in air to furnish heat to us. If methane were free in the air and oxygen were scarce so that we had to purchase it we would consider oxygen to be the fuel. In either case, the amount of heat released would be that for the reaction represented by the following equation. 

HO oxidation of CO is much faster than the reaction with methane, resulting in a mean CO lifetime of about two months, but considerably slower than reaction with the majority of the nonmethane hydrocarbons. Table I gives representative removal rates for a number of atmospheric organic compounds their atmospheric lifetimes are the reciprocals of these removal rates (see Equation E4, below). The reaction sequence R31, R13, R14, R15 constitutes one of many tropospheric chain reactions that use CO or hydrocarbons as fuel in the production of tropospheric ozone. These four reactions (if not diverted through other pathways) produce the net reaction... 

In the search of high-performance SOFC anode, doped ceria have been evaluated as possible anode materials [9,10]. Comparing Ni-samaria-doped ceria (SDC) with Ni-YSZ, the Ni-SDC anode exhibits higher open-circuit voltages and a lower degree of polarization with either methanol as the fuel, as shown in Fig. 5, or methane as the fuel, as shown in Fig. 6. It was found that the depolarization ability of the anode is associated with the catalytic activity, the electrical conductivity, and the oxygen ionic conductivity of the anode materials [9]. It was also found that the anodic polarization and electro-catalytic activity strongly depend on the Ni content in the anode, and the optimum result for the Ni-SDC anode is achieved with 60... 

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