What combustion technique is used to reduce the initial excess air in the combustion process?

Staged combustion is a technique designed to reduce the initial excess air during the combustion process. This method involves dividing the fuel feed into stages, where the primary combustion occurs with a controlled, reduced amount of air. By optimizing the air-to-fuel ratio in different stages, staged combustion minimizes the excess air that can lead to inefficiencies and higher levels of pollutants, such as nitrogen oxides (NOx).

This approach effectively allows for more complete combustion of the fuel by ensuring that there is sufficient fuel present to react with the available oxidizer in a more controlled manner. The controlled stages of combustion enhance the overall efficiency of the combustion process while also addressing emissions, making it a preferred method in many industrial applications.

In contrast, continuous combustion generally implies a steady and constant supply of fuel and air, which may not effectively address the issue of initial excess air. Partial oxidation is a method often used for gasification and may not focus specifically on reducing excess air. Complete combustion requires a stoichiometric ratio of air to fuel, where all fuel is burned completely but does not address the management of excess air before combustion starts. Thus, staged combustion is the most effective technique for reducing initial excess air.