The combustion of fuel is a complex chemical reaction process in which combustible substances in the fuel react rapidly with oxygen in the air at an appropriate temperature, producing a bright flame and releasing a large amount of heat energy. In combustion, we can divide it into two main types: complete combustion and incomplete combustion. Complete combustion means that there is no unburned fuel remaining in the flue gas during the combustion process, while incomplete combustion means that there is still incompletely burned fuel in the flue gas.

In the combustion of boiler fuel, we pursue complete combustion, and complete combustion of fuel requires the synergy of many factors, including appropriate oxygen supply, high-quality fuel, appropriate temperature and pressure, and uniform mixing and distribution. and advanced burner design and control systems. Today we will introduce in detail the combustion methods of boiler fuel, which are classified according to different combustion processes and technical characteristics:

Stratified combustion (fire bed combustion):

Stratified combustion is a method in which solid fuel is distributed on the grate at a certain thickness and then ignited. This combustion method is generally suitable for various types of coal and has relatively low requirements on particle size. However, if there is insufficient oxygen supply or insufficient mixing of air and fuel, incomplete combustion may result, reducing combustion efficiency. Although stratified combustion has the advantages of maintaining a high temperature in the fuel layer, being easy to stabilize, not easy to flame out, and easy to ignite, it is more suitable for small-capacity boilers.

Suspension combustion (fire chamber combustion):

Suspension combustion is to spray fuel into the furnace in the form of powder, mist or gas together with air, and then burn it in a suspended state in the tall furnace. This method has the advantages of rapid ignition, complete combustion, high thermal efficiency, adaptability to external load changes, and automated operation. However, it is sometimes difficult to maintain combustion stability and more fly ash may be produced.

Cyclone Burning:

Cyclone combustion is a stable combustion method in which air and fuel enter the combustion chamber in a tangential direction, where a high-speed airflow is formed, producing a strong spiral motion for combustion. The advantages of this method include stable combustion, high efficiency, adaptability to a variety of coal types and high ash capture capacity. However, it requires a large amount of ventilation energy and the equipment structure is relatively complex, and when high-ash content coal is used, it may result in greater ash loss.

Boiling combustion (fluidized bed combustion):

Boiling combustion is a method in which air is blown at an appropriate speed in the furnace to suspend the fuel particles at a certain height, mix with the air to form a fluid, and burn in a fluidized boiling state. This method is also called fluidized bed combustion. It has the advantages of stable combustion, high efficiency, adaptability to a variety of coal types, high ash capture capacity and automated operation. However, it requires a large amount of ventilation energy and the equipment structure is complex, and when high-ash content coal is used, it may result in greater ash loss.

Conclusion

In summary, the combustion of fuel is a critical process used to generate heat and energy. In the combustion of boiler fuel, different combustion methods and technologies are widely used to meet energy needs under different needs and conditions. Each combustion method has its own unique advantages and limitations, from the stability of the fuel layer of stratified combustion to the high efficiency of suspension combustion, to the stability and adaptability of cyclone combustion, and the stability and high capture efficiency of boiling combustion. gray ability.

In practical applications, choosing the appropriate combustion method depends on several factors, including fuel type, boiler capacity, combustion efficiency, environmental requirements and degree of automation. Regardless of method, careful engineering and operation are required to ensure that the combustion process is efficient, environmentally friendly, and safe. Continuous advancement and innovation in boiler combustion technology will help to use energy resources more efficiently and reduce environmental impact to meet the challenges of future energy demand.