Common Problem

1. Slurry quality and calcium-sulfur ratio The concentration of limestone slurry and the molar ratio of calcium to sulfur directly affect reaction sufficiency. A higher calcium-sulfur ratio provides more absorbent to capture SO₂ and lifts efficiency, yet excessively high ratio increases reagent cost and gypsum impurity. Insufficient limestone leads to incomplete sulfur dioxide absorption and low removal rate.

2. Liquid-gas ratio and contact time A higher liquid-gas ratio creates more slurry droplets for gas-liquid contact. Sufficient residence time of flue gas inside the absorption tower enables full mass transfer between SO₂ and limestone slurry. Too small liquid-gas ratio or short contact time will reduce desulfurization performance obviously.

3. Flue gas parameters High flue gas temperature weakens the solubility of sulfur dioxide in slurry and cuts efficiency. High inlet SO₂ concentration may exceed the absorption capacity of the system if absorbent supply cannot be adjusted timely. Dust carried by raw flue gas will cover limestone particles and hinder chemical reactions.

4. Oxidation air volume Forced oxidation air oxidizes calcium sulfite into stable calcium sulfate dihydrate. Inadequate aeration causes accumulated sulfite to restrain the absorption reaction of SO₂, lowering overall desulfurization effect.

5. Slurry pH value The suitable pH range of circulating slurry is 5.0–5.8. Low pH reduces limestone dissolution rate and weakens SO₂ absorption capacity; overly high pH inhibits oxidation reaction and deteriorates gypsum quality.

6. Operation and equipment status Blocked spray nozzles, damaged demisters or uneven slurry distribution reduce effective gas-liquid contact area. Abnormal circulation pumps and insufficient slurry supply will also restrain stable high desulfurization efficiency.