Fire- Oxygen Relationship

Without fire, it’s possible we would not exist. Fire has had a variety of meanings throughout human history.

In some civilizations people have even worshiped this “interesting chemical process “ by sanctifying with fire.

Today, we will only approach ordinary and scientific usages.

There are 3 elements required for the formation of fire and occurring in flame. According to the chemistry, we call this the combustion triangle.

1.) Material that will burn in the environment (Fuel)
2.) Oxygen
3.) Ignition temperature, (Energy)

We also need the presence of these elements to provide the ideal combustion in gas burners. Typically the oxygen component has not been properly emphasized as much energy or fuel.

A gas burner requires oxygen in two stages; primary and secondary. Gas fuel needs to mix with oxygen before it will form a flame. The oxygen provided in the first phase is called primary oxygen.

Up to 70 percent of the oxygen needed can be mixed with gas. Failure to provide adequate oxygen at this stage may lead to deterioration in flame quality, reduced efficiency and increased waste gases. On the other hand if the primary oxygen is too great it will cause a flame imbalance, leading to fluctuations and flying out.

The second stage is called secondary oxygen and is required for burning after the ignition temperature is reached. If there is not enough oxygen at this stage, the flame does not occur and in order to combust it travels instead to a location with the oxygen. Without a sufficient oxygen level in the proximity of the burner, the flame will lift up and cause flame extension deformation.

This situation will exacerbate and even affect the flame continuity and will ultimately cause extinction of the flame. Waste gases are generated during combustion. Carbon monoxide, carbon dioxide, water vapor, carbon and nitrogen are released. (CO, CO2, H2O, C1-N2). The wastes CO2 and CO are life threatening. Therefore, laws limit the amount of these emissions.

This waste gas needs to be removed from the environment. Otherwise the secondary oxygen cannot reach the desired location. The inlet vents, which are sufficient for the new oxygen supply, and the flue from which the smoke is to be removed must be present. If the chimney size, cross-section, shape and position are not correct and sufficient, the secondary oxygen cannot successfully arrive into the burner environment and correct combustion will not occur. As users, we sometimes overlook proper chimney conditions and we look for problems in other places.

Adequate testing prior to finalizing the design helps us determine the correct chimney design. We should remember that the principle of the rise of heated gases is an important aid in the design of the chimney.


Mehmet KEKEÇ