Limestone/gypsum wet desulfurization is a process to desulfurize flue gas. It has the advantages of mature technology, low investment, high efficiency, low operating cost, and it is suitable for large capacity units. It's the most widely used desulfurization process in the world.
The limestone with high calcium content is crushed to meet the feeding requirements of the mill.
The suitable raw materials are continuously sent to the grinding chamber of the main machine through the feeder for grinding. The milled fine powder rises under the action of the air flow of the fan and is sent to the classifier for classification. The qualified fine powder enters the collection stage through the air outlet pipe.
The dust gas from the mill enters the cyclone collector through the air outlet pipe of the main engine, and under the action of centrifugal force, most of the finished fine powder is separated and collected, and transported to the finished product conveying stage through the screw conveyor. At the same time, the exhaust gas is transformed into clean gas and discharged through the pulse dust collector.
The finished mineral powder is sent to the bucket elevator by the screw conveyor, and then enters the slender deep bin finished material tank. The dust gas in the tank is collected by the top dust remover, and then the finished product is stored in the finished product tank, and the clean gas is discharged.
The finished stone powder is transported to the absorption tower after pulping. The slurry in the absorption tower is sent to the spray device for spray by the circulating pump. Chemical reaction with SO2 entering the absorption tower to achieve the purpose of desulfurization.
In order to ensure the comprehensive utilization of desulfurization gypsum and reduce waste water discharge, the content of CaCO3 in limestone used for desulfurization should be higher than 90%. The fineness of limestone powder should guarantee 90% screening rate of 250mesh for boilers burning medium and low sulphur fuel coal, and 90% screening rate of 325mesh for boilers burning medium and high sulphur content coal. Quicklime can also be used as absorbent. The purity of quicklime should be higher than 85%.
