Methane and Oxygen Gases Reaction | CH4 + O2
Methane, a combustible gas, is used to generate heat by burning with oxygen gas in heat requirement processes. As products, carbon dioxide gas and water are given if complete combustion is achieved. Otherwise, carbon monoxide can be given as another product if the supplied oxygen gas amount is not sufficient. In this tutorial, we will see how methane is combusted successfully and how it is practically used in industry.
CH4(g) + 2O2(g) → CO2(g) + 2H2O
In this tutorial, we will discuss followings.
Stoichiometric balanced chemical reaction of methane and oxygen gases
One mole of methane reacts with two moles of oxygen gas and produce one mole of carbon dioxide and two moles of water.
Heat and power generation
Under the controlled combustion of methane gas with oxygen gas, heat can be generated. The generated heat can be used to generate electricity. The common concept of biogas generation uses this kind of technology to generate electricity. In a biogas generation plant, a biological system is developed to generate biogas (which mainly contains methane gas, hydrogen sulfide, and nitrogen gas in minor quantities).
Thermal energy of the methane and oxygen reaction
Enthalpy of combustion of methane gas per unit mass (kg) or per mole is used to calculate how much energy can be generated (or released) for a specific requirement after combustion of a defined quantity of methane gas. We will show you how those calculations are done with a few examples in this tutorial.
- Standard enthalpy of combustion of methane (mol basis): -890.16 kJ/mol
- Standard enthalpy of combustion of methane (weight basis): 55.514 MJ/kg
Example: Calculation of heat generation due to methane combustion
How much energy is released if 25g of methane gas is burnt with excess oxygen gas.
According to the value of standard enthalpy of combustion of methane, you know how much energy is generated if 1kg of methane gas is completely burnt. In this example, you only burn 25g of methane gas. Therefore, it is straightforward to calculate the generated heat.
- Heat generated by 25g of methane combustion = 55.514 * 25/1000
- Heat generated by 25g of methane combustion = 1.39 MJ
If a water heating system is developed to absorb heat from the above combustion process, calculate what is the final temperature of the water after absorbing heat. Use following data for calculations.
- Initial temperature of water = 300C
- Efficiency of heat transferring of the equipment = 80%
- Total amount of water= 10kg
- Specific heat capacity of water = 4.2 KJ/ mol
Calculate amount of heat transferred to water
- Total energy transferred to water = 1.39 * 80/100
- Total energy transferred to water = 1.11 MJ
Calculate final temperature of water after water absorbs heat
Use the equation, Q = mc(T1 - T2)
- 1.11 * 103 = 10 * 4.2 * (T - 30)
- T = 56.430C
Health, safety, and environmental impacts
Because this reaction involves some gases, there may be health and safety measures and environmental impacts. Here, we can discuss them.
Health and Safety
Low concentrations of methane gas are non-toxic. But, in higher concentrations, methane can displace oxygen gas to make breathing issues. But, methane is a highly inflammable chemical that can result in sudden explosions.
Environmental impacts
Methane is a leading greenhouse gas than carbon dioxide. Therefore, it has a higher potential for global warming.
Questions
If methane can be used as a fuel, why it is still not much used instead of LPG?
Methane cannot be liquidized by increasing the pressure as LPG in room temperature. Therefore, there are practical issues of storing methane.
Which chemical can generate more heat, methane or ethane?
Both methane and ethane belong to alkanes in organic chemistry. Standard enthalpy of combustion of ethane (weight basis)is 51.87 MJ/kg. Therefore, methane can generate more energy by burning 1kg.