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How to Calculate Percentage of Excess Air in Combustion Process

In this post, I want to share how to calculate percentage of excess air flow in combustion process. The known data are:

  1. Fuel composition
  2. Flue gas composition

Before we jump into the calculation, we need to understand about excess air and why we need it.

To ensure complete combustion of the fuel used combustion chambers are supplied with excess air. Excess air increases the amount of oxygen to the combustion and the combustion of fuel. When fuel and oxygen from the air are in perfect balance – the combustion is said to be stoichiometric.

The combustion efficiency increases with increased excess air – until the heat loss in the excess air is larger than the heat provided by more efficient combustion.

Let’s see example below. Read More