Alberta Boilers Safety Association (ABSA) Practice Test

What is a common method of ensuring proper combustion in a boiler?

1. Decreasing the fuel input

2. Increasing the water temperature

3. Controlling the air-fuel mixture

4. Installing a secondary burner

The correct answer is: Controlling the air-fuel mixture

Controlling the air-fuel mixture is a common and essential method for ensuring proper combustion in a boiler. This involves balancing the amount of combustion air with the amount of fuel being supplied to the burner. An optimal air-fuel mixture is crucial because it affects the efficiency and safety of the combustion process. If the mixture is too rich (excess fuel), it can result in incomplete combustion, leading to higher emissions of pollutants like carbon monoxide and soot formation. Conversely, if the mixture is too lean (excess air), it can reduce the heat output and efficiency of the boiler while also increasing combustion temperatures, which can lead to operational issues and equipment damage. In contrast, while decreasing the fuel input can affect combustion, it is not a method that directly optimizes the combustion process itself. Increasing the water temperature relates to the boiler's efficiency but does not directly influence the combustion quality. Installing a secondary burner might be a solution for a particular scenario but does not address the fundamental parameters of combustion control. Therefore, managing the air-fuel mixture is the most direct and effective approach to ensuring that combustion occurs correctly within a boiler system.