For optimal performance in a fluidized bed coal boiler, the coal should be crushed to what size or smaller?

For optimal performance in a fluidized bed coal boiler, coal should be crushed to 1/4 inch or smaller. This size is ideal because it ensures that the coal particles are small enough to be effectively suspended in the fluidized bed. The fluidization process relies on the ability of the air flow to lift and carry the coal particles, creating a uniform mixture that allows for better combustion efficiency and heat transfer.

When coal is ground to this size, it leads to more complete combustion, reduced emissions, and improved heat output. Additionally, smaller particles have a larger surface area relative to their volume, which facilitates a quicker and more efficient reaction with the air, further enhancing performance.

Crushing coal to sizes larger than 1/4 inch can negatively impact the fluidization quality, leading to incomplete combustion and greater emissions, which are detrimental to both efficiency and environmental compliance.