What type of fuels are typically categorized as gaseous fuels?

Gaseous fuels are typically characterized by their state of matter at normal temperature and pressure, which is gas. Natural gas and propane are both examples of gaseous fuels, as they are found in a gaseous state under the appropriate conditions. They are commonly utilized in various applications, including heating, cooking, and as engine fuel, due to their clean-burning properties and high energy content.

In contrast, solid and liquid fuels, such as wax, paper, and gasoline, do not fit the definition of gaseous fuels. Solid fuels are in a solid state and typically require a combustion process to convert them to gas, while liquid fuels exist in liquid form and may require vaporization to utilize their combustive qualities. Large quantities of logs and biomass also fall into the category of solid fuels, and while they can produce gases when combusted, they are not classified as gaseous fuels in their natural state.