半干法烟气脱硫技术是一项用于35T/H～670T/H容量锅炉的烟气脱硫技术，脱硫效率可达85%以上。

The semi-dry flue gas desulfurization technology is a type of desulfurization technology for flue gas from boilers with a capacity ranging from 35T/H to 670T/H, and its desulfurization efficiency can reach over 85%.

喷雾干燥是一种相对较新的FGD技术，相对于湿法工艺而言，其初投资较低，但脱硫剂用量较大，因而常常用于燃用中低硫煤（<1.5%）的中小型锅炉。

Spray drying is a relatively new FGD technology. Compared with the wet process, it has a lower initial investment but requires a larger amount of desulfurization agent. Therefore, it is often used in small and medium-sized boilers that burn medium and low-sulfur coal (<1.5%).

喷雾干燥脱硫技术是利用喷雾干燥的原理，来达到烟气脱硫的目的。喷雾干燥脱硫工艺分为5个步骤：（1）吸收剂制备；（2）吸收剂浆液雾化；（3）雾滴与烟气接触混合；（4）蒸发-二氧化硫吸收；（5）废渣排除，其中2、3、4三个步骤均在喷雾吸收塔中进行。

The spray drying desulfurization technology utilizes the principle of spray drying to achieve the purpose of removing sulfur dioxide from flue gas. The spray drying desulfurization process consists of five steps: (1) preparation of the absorbent; (2) atomization of the absorbent slurry; (3) contact and mixing of the droplets with the flue gas; (4) evaporation and sulfur dioxide absorption; (5) removal of waste residue. Steps 2, 3, and 4 are all carried out in the spray absorption tower.

　　化学反应过程

Chemical reaction process

　　当雾化的浆液在吸收塔中与烟气接触后，吸收剂开始蒸发，烟气冷却并增湿，石灰浆同SO2反应生成干粉产物。整个反应分为：SO2被液滴吸收生成亚硫酸钙，达到饱和后结晶析出；部分溶液中的CaSO3与溶于液滴中的氧反应，氧化成硫酸钙，从而结晶析出。随着脱硫过程中溶解的氢氧化钙消耗，更多的氢氧化钙固体进一步溶解以维持脱除二氧化硫的反应继续进行。

When the atomized slurry comes into contact with the flue gas in the absorption tower, the absorbent begins to evaporate, the flue gas cools down and becomes humid, and the lime slurry reacts with SO2 to form dry powder products. The entire reaction can be divided into: SO2 is absorbed by the droplets to form calcium sulfite, and when saturation is reached, crystals precipitate out; some CaSO3 in the solution reacts with the oxygen dissolved in the droplets to oxidize into calcium sulfate, and thus crystals precipitate out. As the calcium hydroxide dissolved during the desulfurization process is consumed, more solid calcium hydroxide further dissolves to maintain the reaction for removing sulfur dioxide to continue.

　　物理过程

Physical process

　　指液滴的蒸发干燥及烟气冷却增湿过程。液滴的干燥大致分为两个阶段：第一阶段由于浆料液滴中固体含量不大，基本上属于液滴表面水的自由蒸发，蒸发速度快而相对恒定。随着水分蒸发，液滴中固体含量增加，当液滴表面出现显着固态物质时，便进入第二阶段。由于蒸发表面积变小，水分必须穿过固体物质从颗粒内部向外扩散，干燥速率降低，液滴温度升高并接近烟气温度，最后由于其中水分蒸发殆尽形成固态颗粒而从烟气中分离。

It refers to the evaporation and drying process of droplets as well as the cooling and humidification process of the gas. The drying of droplets is roughly divided into two stages: The first stage is mainly the free evaporation of water on the surface of the liquid droplets, which occurs when the solid content in the slurry droplets is not high and is relatively fast and constant. As the moisture evaporates, the solid content in the droplets increases. When significant solid substances appear on the surface of the droplets, it enters the second stage. Due to the reduced surface area of evaporation, the moisture must pass through the solid substances from the inside of the particles to the outside, resulting in a reduced drying rate, an increase in droplet temperature approaching the temperature of the gas, and finally, as all the moisture evaporates completely, solid particles are formed and separated from the gas.

　　液滴从蒸发开始到干燥所需的时间，对吸收塔的设计和脱硫率都非常重要。影响液滴干燥时间的因素有液滴大小，液滴含水量以及趋进绝热饱和的温度值。

The time required for a droplet to go from evaporation to drying is of great significance for the design of the absorption tower and the desulfurization rate. The factors influencing the drying time of the droplets include droplet size, droplet moisture content, and the temperature value at which the droplets approach adiabatic saturation.