Desulfurization principle and process flow

The desulfurization principle and process flow vary depending on the specific technology, but usually involves converting sulfur dioxide (SO₂) in flue gas into other compounds or substances, thereby reducing its pollution to the environment. The following is an overview of a typical wet desulfurization principle and process flow:

Desulfurization principle

Wet desulfurization technologies typically use limestone (CaCO₃) or lime (CaO) as desulfurizing agents that react with water to form calcium hydroxide (Ca (OH) ₂). When the flue gas containing SO₂ enters the absorption tower, SO₂ chemically reacts with the limestone/lime slurry sprayed down in the tower to generate calcium sulfite (CaSO₃) or calcium sulfate (CaSO₄). These compounds can then be converted to gypsum (CaSO₄ · 2H₂O) or other valuable by-products by further processing.

Process flow

1. Flue gas pretreatment: Flue gas from a boiler or kiln first passes through a dust collector to remove solid particulate matter from it. Then, the flue gas enters the absorption tower through the induced draft fan.

2. Absorption tower: The absorption tower is the core part of the desulfurization system. The flue gas contacts countercurrent with the sprayed limestone/lime slurry in the tower, and a chemical reaction takes place to convert SO₂ into calcium sulfite or calcium sulfate. At the same time, the tower is also equipped with a demister for removing water droplets in the flue gas.

Oxidation: In the oxidation zone of the absorption tower, calcium sulfite is oxidized to calcium sulfate by the blown air.

3. Gypsum generation: Calcium sulfate reacts with water to form gypsum (CaSO4·2H₂O). The gypsum can be further processed by dewatering equipment to form a dry gypsum product.

4. By-product handling: Gypsum or other by-products produced in the desulfurization process can be sent to the by-product processing system through conveying equipment for further processing and utilization.

5. Wastewater treatment: The wastewater generated by the desulfurization system needs to be treated to remove harmful substances from it, and discharged or reused after meeting the discharge standards.

6. Monitoring and control: The whole desulfurization system is equipped with monitoring and control equipment, which is used to monitor the emission concentration of flue gas, desulfurization efficiency and other parameters in real time, and adjust the operation parameters of the system as needed to ensure the stable operation and efficient desulfurization of the system.

It should be noted that different desulfurization technologies may adopt different principles and process flows. Therefore, in practical application, it is necessary to select the appropriate desulfurization technology and process flow according to the specific situation.