When gas is burned, the oxygen in the air mixes with hydrogen and carbon from the gas. This interaction creates carbon dioxide, water, and a release of heat. The general composition of air is 21% oxygen, 78% nitrogen, and 1% miscellaneous gases. During combustion, nitrogen weakens the reaction thereby removing energy from the combustion's gaseous byproduct. Increasing the oxygen content in this type of system would prevent energy loss.
Oxygen-enriched combustion is a common practice in industrial furnaces in the glass-melting industry. To increase the oxygen content in the combustion air, liquid oxygen is used or pressure swing absorption devices operate to remove nitrogen. There is another option involving oxy-fuel burners in addition to standard burners to aid the process. In addition, there are combustion headers that use pure oxygen to increase the oxygen content in combustion air while others opt for mixing in the oxygen. Another alternative includes staging the combustion process and diversifying the oxygen content during various combustion stages. The final option involves artificially injecting oxygen into or near the fuel's flame to counteract the presence of the nitrogen.
Oxygen-enriched combustion can decrease the toxic emission of carbon monoxide, nitrogen oxide, and hydrocarbons. The process is environmentally friendly.
Having a higher concentration of oxygen available increases the stability of the combustion and, in turn, can lead to higher combustion temperatures. This results in a more effective transfer of heat.
Since the oxygen content of the air increases, there is less nitrogen available to remove heat from the furnace so the process is more efficient.
The same input of fuel can yield increased productivity because the furnace flame's temperature is higher. Therefore, less money can be spent on fuel.