| 摘要 |
<p>A flue gas desulfurization process by cycling absorption with magnesium sulfite regenerated by calcium based alkali compound, in which flue gas containing sulfur dioxide is introduced into an absorption tower (1) continuously. Sulfur dioxide is circularly absorbed from the flue gas by magnesium sulfite absorption liquid, and magnesium sulfite is converted to magnesium bisulfite. A portion of the absorption liquid from tower bottom is branched away to perform double decomposition reaction with calcium hydrate to obtain mixed slurry of magnesium hydrate and calcium sulfate. Another portion of the absorption liquid from tower bottom is also branched and introduced into a regeneration system outside the tower, and regenerated with the mixed slurry of magnesium hydrate in which magnesium bisulfite is regenerated to magnesium sulfite. Solid-liquid separation is conducted to recover the mixed slurry of magnesium sulfite and calcium sulfate, and the filtrate is returned to the absorption tower (1) for cycling absorption. The recovered mixture of magnesium sulfite and calcium sulfate is oxidized with air, as such magnesium sulfite is oxidized into magnesium sulfate. The magnesium sulfate filtrate is recovered and returned for cycling absorption. Sludge generated by filter-pressing is transported outwards for comprehensive utilization.</p> |
