Most desulfurizers in environmental protection desulfurization process are limestone powder. The quality, fineness, and particle distribution of limestone powder are one of the key factors affecting the desulfurization effect. It’s important for the entire desulfurization process to select the appropriate limestone powder process and equipment. Limestone-gypsum flue gas desulphurization wet process is the world’s most technologically advanced and widely used technology for controlling SO2 emissions. More than 90% of thermal power plants in China use limestone-gypsum desulfurization.

desulfurization wet process

Limestone-gypsum desulphurization works on the principle that the limestone powder is added with water to make a slurry. The absorbent is pumped into the absorption tower and is fully in contact with the flue gas. The sulfur dioxide in the flue gas and the calcium carbonate in the slurry and the air spurted from the lower part of the tower. The oxidation reaction produces calcium sulphate. After the calcium sulphate reaches a certain degree of saturation, crystals form dihydrate gypsum. After the gypsum slurry discharged from the absorption tower is concentrated and dehydrated to a moisture content of less than 10%, it is sent to the gypsum silo for storage by a conveyor. The desulfurized flue gas is passed through the demister to remove the droplets, and then heated by the heat exchanger. After warming, it is discharged from the chimney into the atmosphere. As the absorption agent slurry in the absorption tower is in contact with the flue gas through repeated circulation of the circulation pump, the utilization rate of the absorbent is high, the calcium and sulfur are relatively low, and the desulfurization efficiency may be greater than 95%.

Limestone-gypsum desulfurization process is to desulfurize and purify the flue gas after combustion. The medium that absorbs SO2 is limestone powder. The particle size of limestone powder has a great influence on the desulfurization efficiency. The smaller the particle size, the more favorable the absorption of SO2. The preparation of limestone powder has become a prerequisite for desulphurization in thermal power plants and steel plants to increase desulfurization efficiency. On the other hand, the preparation cost of limestone powder has a great influence on the desulfurization cost. The low-cost preparation of high-fine limestone powder technology has become an important part of environmental protection desulfurization technology.

6th June 2018