A secondary combustion chamber is an essential component in many industrial and commercial heating processes, especially in waste incineration and biomass energy production. The purpose of a secondary combustion chamber is to provide a controlled environment for the complete combustion of any unburned particles and gases that may have escaped the primary combustion process. This serves to reduce harmful emissions and ensure maximum energy efficiency.
The science behind secondary combustion chambers lies in understanding the principles of combustion and the conditions necessary for complete combustion to occur. In a primary combustion chamber, fuel is ignited and burned in the presence of oxygen to produce heat energy. However, due to factors such as insufficient air supply, high moisture content in the fuel, or incomplete mixing of fuel and air, there may be unburned particles and gases that escape into the exhaust gas stream.
In a secondary combustion chamber, the unburned particles and gases are reintroduced to a higher temperature environment where they can undergo further reactions and complete combustion. This is achieved by maintaining a high temperature, prolonging the residence time of the gases, and providing an additional supply of oxygen if necessary.
The high temperature in the secondary combustion chamber is essential for promoting the reaction between unburned hydrocarbons and oxygen. This is because at higher temperatures, the kinetic energy of the molecules increases, enabling more collisions between the reactive species. Additionally, the presence of a catalyst in the secondary combustion chamber can further facilitate the combustion reactions by lowering the activation energy required for the reactions to occur.
Prolonging the residence time of the gases in the secondary combustion chamber is crucial for ensuring complete combustion. This is achieved by designing the chamber with sufficient volume and turbulence to allow for thorough mixing and reaction of the gases. The design of the chamber also plays a role in promoting airflow and ensuring uniform distribution of oxygen for efficient combustion.
The additional supply of oxygen in the secondary combustion chamber can be introduced through the use of air injection systems or other means of oxygen enrichment. This allows for the combustion of any remaining unburned fuel as well as the oxidation of carbon monoxide (CO) and other unburned hydrocarbons to less harmful compounds such as carbon dioxide (CO2) and water vapor.
Overall, the science behind secondary combustion chambers involves creating the right conditions for the complete combustion of unburned particles and gases through high temperature, prolonged residence time, and controlled oxygen supply. This not only reduces harmful emissions but also maximizes the energy recovery from the combustion process.
