Which element is NOT typically a part of flue gas composition?

Flue gases are the byproducts of combustion processes, and their composition primarily includes elements and compounds resulting from the burning of fuels. Typically, flue gas consists of nitrogen, oxygen, water vapor, carbon dioxide, and small amounts of other gases.

Argon, on the other hand, is an inert gas that makes up a small portion of the Earth's atmosphere but does not participate in the combustion process. Since argon's role in combustion is negligible, it is not considered a significant component of flue gas.

In contrast, nitrogen is present because it is the most abundant gas in the atmosphere, and while some of it may be involved in the combustion process at high temperatures, it largely passes through the combustion process unchanged. Oxygen is a vital reactant in combustion, leading to the formation of combustion products, including carbon dioxide and water vapor. Water vapor is created during combustion when hydrogen in the fuel combines with oxygen. Thus, argon stands out as the element not typically found in the composition of flue gases.