Fluidized bed combustion boiler

Fluidized Bed Combustion Boiler

Fluidized bed combustion (FBC) is a modern and advanced technology used in combustion of solid fuels such as coal and lignite. Fluidized beds are most commonly used for the burning of fuels because of their supremacy in providing lower emission of polluting components such as NOx and SO2. The key principle of fluidized bed technology is to use a finely divided and evenly blended fuel and sand or ash, suspended in an upward flow of inert gas, such as air. The gas flow also serves to contain and lift the particles, and distributes them uniformly through the bed. The result is a highly efficient and clean burning process.

FBC boilers are composed of a water wall evaporator, a furnace, and an air preheater. The air preheater is used to provide the air necessary for combustion. The air preheater is either a separate device located outside of the furnace, or it may be integrated in the furnace itself. The furnace is designed to hold the material being burned and the gas necessary to maintain the fluidized bed.

Within the furnace the gas expands rapidly, creating a fluidized bed of material, into which the fuel is injected and combusted. The combustion of the fuel generates high heat, which is transferred to the contained material particles and this, in turn, transfers heat through the walls of the furnace to the water, which is then turned into steam and used as a power source.

The fluidized bed is maintained in a state of turbulence and supports burning within the bed. This relative movement of the gas and particles results in better mixing of the combustion materials, promoting improved combustion efficiency. By preventing the oxygen from being completely consumed, the fuel particles remain suspended in the otherwise dense medium. The addition of various additives can also allow FBC to burn cold materials, such as biomass and waste plastics, that are otherwise difficult to burn in traditional combustion practices.

The advantages of a FBC boiler compared to conventional boilers include:

• Reduced emissions of NOx and SO2

• Low ash content and improved fuel efficiency

• Low cost in comparison to other combustion technologies

• Low power consumption

• Stable combustion and high level of automation

• Ability to burn a wide range of fuels, including biomass and waste plastics

• The ability to meet environmental regulations with lower capital investment

FBC boilers represent a modern and efficient way of burning solid fuels, with the added benefit of being able to burn materials like biomass and waste plastic. These advantages make FBC boilers a viable option for power production and industries with higher efficiency than many of its traditional counterparts.