Technical Standards and Safety Authority (TSSA) G3 Practice Exam

What theoretical gas to air ratio is necessary to achieve perfect combustion with an atmospheric natural gas burner?

1. 1 part of natural gas to 10 parts of air

2. 5 parts of natural gas to 5 parts of air

3. 5 parts of natural gas to 15 parts of air

4. 20 parts of natural gas to 1 part of air

The correct answer is: 1 part of natural gas to 10 parts of air

The requirement for perfect combustion with an atmospheric natural gas burner is to achieve a specific ratio of fuel to air that allows for complete oxidation of the fuel while minimizing the formation of by-products like carbon monoxide or unburned hydrocarbons. This ideal ratio is often derived from the stoichiometric equations of combustion. Natural gas is primarily composed of methane (CH4), and the theoretical combustion of methane requires a certain volume of air to ensure all of the methane reacts with oxygen. The combustion process can be summarized by the reaction: CH4 + 2O2 → CO2 + 2H2O This equation reveals that one molecule of methane requires two molecules of oxygen to completely combust. Air is composed of about 21% oxygen, which means it takes a greater volume of air to provide the necessary oxygen for combustion. Therefore, for every part of natural gas, a specific volume of air is needed to accommodate the oxygen requirement and ensure complete combustion occurs. In practical terms, achieving the ideal gas-to-air ratio ensures that there is sufficient air to react with all the available gas, thereby maximizing efficiency and reducing emissions. The correct answer indicates that 1 part of natural gas requires 10 parts of air to achieve this ideal condition, aligning with