Desulfurization of Hexiang Refractory Magnesium Oxide

氧化镁法脱硫法

氧化镁法脱硫法

锅炉烟气由引风机送入吸收塔预冷段，

冷却至适合的温度后进入吸收塔，

往上与逆向流

下的吸收浆液反应，

脱去烟气中的硫份。

吸收塔顶部安装有除雾器，

用以除去净烟气中携带

的细小雾滴。

净烟气经过除雾器降低烟气中的水分后排入烟囱。

粉尘与脏东西附着在除雾器

上，

会导致除雾器堵塞、

系统压损增大，

需由除雾器冲洗水泵提供工业水对除雾器进行喷雾

清洗。

吸收过程发生的主要反应如下：

Mg(OH)

2

 + SO

2

→ MgSO

3

 + H

2

O 

MgSO

3

 + SO

2

 + H

2

O → Mg(HSO

3

)

2

Mg(HSO

3

)

2

 + Mg(OH)

2

→ 2MgSO

3

 + 2H

2

O 

吸收了硫分的吸收液落入吸收塔底，吸收塔底部主要为氧化、循环过程。

氧化过程，

由曝气鼓风机向塔底浆液内强制提供大量压缩空气，

使得造成化学需氧量的

MgSO

3

氧化成

MgSO

4

。这个阶段化学反应如下：

 Magnesium oxide is used for desulfurization. Magnesium oxide desulfurization and magnesium oxide desulfurization are used for desulfurization. The boiler flue gas is fed into the pre-cooling section of the absorption tower by the induced draft fan, cooled to a suitable temperature and then into the absorption tower. It reacts with the absorption slurry under the reverse flow to remove the sulfur in the flue gas. A mist eliminator is installed on the top of the absorption tower to remove small droplets carried in the clean flue gas. The net smoke is discharged into the chimney after it is reduced by a mist eliminator. Dust and dirt are attached to the demister, resulting in blockage of mist eliminator and increase of system pressure loss. It is necessary to wash water pumps with mist eliminator to provide industrial water for spray cleaning of mist eliminator. The main reactions in the absorption process are as follows: Mg (OH) 2 + SO2 MgSO3 + H2O MgSO3 + SO2 + H2O Mg (HSO 3) 2 Mg (HSO 3) 2 + Mg (OH) 2 2MgSO3 + 2H 2, which absorbs sulfur and falls to the bottom of the absorption tower. The bottom of the absorption tower is mainly oxidation and circulation process. During the oxidation process, a large amount of compressed air is forced to be supplied to the slurry at the bottom of the tower by an aeration blower, which causes the oxidation of MgSO3 to MgSO4. In this stage, the chemical reactions are as follows: MgSO3 + 1/2O2 MgSO4 Mg (HSO 3) 2 + 1/2O2 MgSO4 + H2SO3 + Mg (OH) 2 MgSO3 + 2H2O MgSO3 + 1/2O2 MgSO4 circulation process is that the absorbent liquid falling into the bottom of the tower is re-transported to the upper absorption zone of the absorber through slurry circulation pump. The pH of the absorbent liquid at the bottom of the tower is adjusted by 20% magnesium hydroxide slurry injected automatically, and controlled in chain with the acid-base meter. When the bottom slurry pH is lower than the set value, magnesium hydroxide slurry is automatically added to the bottom of the absorption tower through the conveying pump. Under the action of the bottom agitator, the slurry is evenly mixed, and the magnesium hydroxide slurry is stopped when the pH reaches the set value. 20% magnesium hydroxide solution is produced by heating water with magnesium oxide powder or directly using magnesium hydroxide. Because of the impurity of magnesium oxide powder and the low solubility of magnesium hydroxide, the slurry after maturation is very easy to deposit. Therefore, the mixer and the magnesium hydroxide solution pump must run continuously to avoid precipitation at the bottom of the pipeline and absorption tower.