Combustion of methane gas

FIGURE 6.29 The standard reaction enthalpy is the difference in enthalpy between the pure products and the pure reactants, each at I bar and the specified temperature (which is commonly but not necessarily 298 K). The scheme here is for the combustion of methane gas to carbon dioxide gas and liquid water. 

The temperature that a self-sustaining reaction could reach can be estimated, on the high side, by calculating the adiabatic flame temperature (McQuarrie and Simon, 1997). The adiabatic flame temperature is routinely calculated in physical chemistry. An example with the combustion of methane gas will illustrate the salient points. The balanced chemical reaction for the complete combustion of methane is, again... 

Q C99 Natural gas is mainly methane gas. If you have a natural gas furnace, stove, or water heater in your home, you must ensure that these appliances are always running at peak efficiency. In other words, the methane gas should undergo complete combustion so that carbon monoxide is not produced. Write a balanced chemical equation to show the complete combustion of methane gas. Write a second balanced equation to show the incomplete combustion of methane gas. 

Rossini (1 ) measured the enthalpy of combustion of methane gas. His value at 298.15 K was corrected to the presently accepted molecular weight of water. The enthalpy of formation was calculated using -68.3174 and -94.0540 kcal mol" for the enthalpy of formation of H20(t) and (g), respectively. 

For the complete combustion of methane gas, CH, represented above, AH is - 802 kJ. What is the value of AH if tlie combustion produced liquid water HjOtZ), rather than water vapor 1 I JlCg) (AH for the phase change 1 bO(g) HjOtZ) is -A4 kJ moT. )... 

Problem 12.17. Methane, octane, and polyethylene are members of the alkane family. Combustion of methane (gas heating) and octane (liquid-burning engines) are used as sources of energy. In eontrast polyethylene is used for producing objects such as milk, food, and detergent bottles. What macroscopic property is responsible for this difference What molecular-level property determines this difference ... 

The combustion of methane gas, the principal constituent of natural gas, is represented by the equation... 

The heats of combustion of methane and butane are 890 kj/mol (212 8 kcal/mol) and 2876 kJ/mol (687 4 kcal/mol) respectively When used as a fuel would methane or butane generate more heat for the same mass of gas" Which would generate more heat for the same volume of gas" ... 

Flame or Partial Combustion Processes. In the combustion or flame processes, the necessary energy is imparted to the feedstock by the partial combustion of the hydrocarbon feed (one-stage process), or by the combustion of residual gas, or any other suitable fuel, and subsequent injection of the cracking stock into the hot combustion gases (two-stage process). A detailed discussion of the kinetics for the pyrolysis of methane for the production of acetylene by partial oxidation, and some conclusions as to reaction mechanism have been given (12). 

Every chemical reaction is accompanied by the transfer of energy as heat. For example, complete reaction with oxygen is called combustion and the combustion of methane, the major component of natural gas, is the following reaction ... 

As another illustration of the use of Equation, we calculate the enthalpy of combustion of methane, the principal component of natural gas. We begin with the balanced chemical equation ... 

C06-0121. A home swimming pool contains 155 m of water. At the beginning of swimming season, the water must be heated from 20 °C to 30 °C. (a) How much heat energy must be supplied (b) If a natural gas heater supplies this energy with an 80% heat transfer efficiency, how many grams of methane must be burned (The heat of combustion of methane is -803 kJ/mol.)... 

Since air comprises about 21% oxygen and 79% nitrogen, with traces of other gases, e.g. CO2, complete combustion of methane (i.e. natural gas) in air can be represented as ... 

Gas may be formed by microbiological degradation of organics, evaporation and volatilization of volatile materials, or chemical reactions. The high combustibility of methane—a major component of landfill-generated gas—is a potential hazard. The emission of gas can be accelerated by elevated temperatures and venting conditions. Air pollution, which may result from gaseous... 

Heat Release Rate From Fuel Gas. The fuel gas used in these tests was a mixture of natural gas supplied by the local gas company. This gas mixture contains approximately 90 percent methane and small fractions of ethane, propane, butane, C02, and nitrogen, as analyzed by Brenden and Chamberlain (6). Although composition of the gas changes with time, the changes were small in our case. A statistical sample of gross heat of combustion of fuel gas over several months showed a coefficient of variation of 0.7 percent. Also, the gross heat of combustion of natural gas reported by the gas company on the day of the test did not vary significantly from test to test. Thus, we assumed that the net heat of combustion was constant. 

A furnace that provides heat by burning methane gas (CH4) must have the correct mixture of air and fuel to operate efficiently. What is the mole ratio of air to methane gas in the combustion of methane Hint Air is 20% oxygen. 

When discussing the efficiency of a fuel such as natural gas, you need to specify how that fuel is being used. Consider, for example, natural gas. Natural gas is primarily methane. Therefore, you can estimate an ideal value for energy production using the enthalpy of combustion of methane. 

Production of ammonia (NH ) Anhydrous (dry) ammonia is the fifth most produced industrial compound. The Haber-Bosch process uses steam on hot coke, which is mostly used in South Africa. In the United States, it is mostly produced from partial combustion of natural gas (methane) or by combining several gases using steam. Other methods use coke-oven gas, refinery gas (mostly methane), or even solar energy. Ammonia is toxic if inhaled and has a high pH value when mixed with water (hydration) to form ammonium hydroxide (NH OH), which has many uses, including as a household cleaner. Ammonia forms many compounds, including ammonium nitrate in fertilizer, rocket fuel, and explosives. Ammonia is also explosive when mixed with mercury or silver or when mixed as part of nitrocellulose. 

The combustion of natural gas, methane, to produce heat can be summarized in the following reaction ... 

The composition of the synthesis gas, particularly the concentrations of hydrogen, carbon monoxide, and carbon dioxide, affects the atmosphere throughout the reactor directly, and also indirectly by its effect on the composition of the recycle gas. Synthesis gas, prepared by partial combustion of methane or some less hydrogen-rich carbonaceous material, lacks sufficient hydrogen for the conversion of all the carbon monoxide to hydrocarbons, and in this sense the synthesis gas is deficient in hydrogen. Stoichiometrically methane has sufficient hydrogen to convert all its carbon to olefins by the two-step process ... 

Combustion is an oxidation-reduction reaction between a nonmetallic material and molecular oxygen. Combustion reactions are characteristically exothermic (energy releasing). A violent combustion reaction is the formation of water from hydrogen and oxygen. As discussed in Section 9.5, the energy from this reaction is used to power rockets into space. More common examples of combustion include the burning of wood and fossil fuels. The combustion of these and other carbon-based chemicals forms carbon dioxide and water. Consider, for example, the combustion of methane, the major component of natural gas ... 

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