Experimental Study on Abrasion Characteristics of Rapidly Hydrated Sorbent for Moderate Temperature Dry Flue Gas Desulfurization

A rapidly hydrated sorbent for moderate temperature (600-800 degrees C) dry flue gas desulfurization (FGD) was developed with the fine calcium-containing particles formed by hydrating the lime adhering to the fly ash particles to increase the residence time of these fine particles in the circulating fluidized bed (CFB) reactor to increase the desulfurization efficiency. Abrasion of the rapidly hydrated sorbent was investigated by sieving the sorbent for 1 h with a sieving displacement of 1.5 mm. The abrasion ratio, R-a (%), which is the percentage of calcium (Ca) mass below the sieve to the original sorbent mass, was used to represent the sorbent abrasion characteristics. The sorbent desulfurization ability, R-d (mg/g), was represented by the mass of sulfur dioxide (SO2) absorbed per gram of sorbent. The experimental results show that R-a decreased from 7.35% to 3.16% as the fly ash particle size increased from 74 to 182 mu m, while R-d of sieved sorbent increased from 124 to 139 mg/g, indicating that sorbent made from larger fly ash particles had a lower abrasion ratio and retained higher desulfurization ability after sieving. The sorbents prepared by firing, alkali, and acid modified fly ash particles had lower abrasion ratios and higher desulfurization abilities than those of sorbent prepared from the original fly ash.