Principle of desulfurization of desulfurized magnesia

A demister is installed at the top of the absorption tower to remove fine droplets carried in the net flue gas. The net flue gas is discharged into the chimney after the mist remover reduces the moisture in the flue gas. Dust and dirt adhere to the defogger, which will cause the defogger to become clogged and the system pressure loss to increase. The defogger flushing water pump is needed to provide industrial water to spray the defogger.

Cyclic process

The absorption liquid falling into the bottom of the tower is re-delivered to the upper absorption zone of the absorption tower through the slurry circulation pump. The pH of the bottoms absorption liquid is adjusted by the auto-injection of 20% magnesium hydroxide slurry and is controlled by an acid-base meter. When the pH of the bottom slurry is lower than the set value, the magnesium hydroxide slurry is automatically replenished to the bottom of the absorption tower by the transfer pump, and the slurry is uniformly mixed under the action of the bottom agitator, and the supplementary hydrogenation is stopped when the pH reaches the set value. Magnesium slurry. The 20% magnesium hydroxide solution is produced by heating the water with magnesium oxide powder, or directly using magnesium hydroxide. Because the magnesium oxide powder is impure, and the solubility of magnesium hydroxide is very low, the matured slurry is very easy to deposit, so the mixer and the mixer The magnesium hydroxide solution transfer pump must be operated continuously to avoid precipitation of the pipeline and the bottom of the absorption tower.

Oxidation process

A large amount of compressed air is forced from the aeration blower into the bottom slurry to oxidize the chemical oxygen demand of MgSO3 to MgSO4. The chemical reaction at this stage is as follows:

MgSO3 + 1/2O2 → MgSO4

Mg(HSO3)2 + 1/2O2 → MgSO4 + H2SO3

H2SO3 + Mg(OH)2 → MgSO3 + 2H2O

MgSO3 + 1/2O2 → MgSO4

Absorption process

The main reactions that occur during the absorption process are as follows:

Mg(OH)2 + SO2 → MgSO3 + H2O

MgSO3 + SO2 + H2O → Mg(HSO3)2

Mg(HSO3)2 + Mg(OH)2 → 2 MgSO3 + 2H2O

The absorption liquid that absorbs sulfur falls into the bottom of the absorption tower, and the bottom of the absorption tower is mainly an oxidation and circulation process.