Experimental study on the porous structure of variously sized fly ash particles under different combustion conditions

With the aid of the N₂ isothermal (77 K) adsorption method, the porous structure of fly ash, of different granular sizes, emitted in coal fired power plants, under different combustion conditions, were tested and analyzed with their specific surface areas calculated by the BET method. Adsorption isotherms under low, and desorption isotherms under high pressure conditions, were studied with HK and BJH methods. Results show, that the ash particles' specific surface area, as well as their pore volume, increase with rising oxygen concentration, rising calcium to sulfur ratio and reducing coal to coke ratio; on the other hand with reducing granular size, especially when below 2.5 μm, the porous structure gets more developed, causing specific surface area and pore volume to rise rapidly.