Common Problem

1. Reaction medium and principle: Wet desulfurization sprays slurry made of limestone or lime, enabling sufficient contact and mass transfer reaction between flue gas and liquid. Dry desulfurization injects slaked lime powder into flue ducts to remove sulfur dioxide via gas-solid reaction, whose reaction efficiency is inferior to that of the wet process.

2. Desulfurization efficiency: The efficiency of the wet process stably reaches 95%~99%, meeting ultra-low emission standards. The dry process only achieves 80%~90% desulfurization, failing deep desulfurization and only applicable to loose emission limits.

3. Water consumption and by-products: The wet process consumes large volumes of water and generates desulfurization wastewater requiring treatment. Its by-product is high-purity dihydrate gypsum available for comprehensive recycling. The dry process barely consumes water and discharges no wastewater, yet its by-product is mixed desulfurization ash with complex components hard to reuse.

4. Equipment and applicable working conditions: Wet desulfurization features bulky equipment and numerous supporting systems, suitable for large power plants and high-temperature flue gas from large-capacity boilers. Dry desulfurization boasts compact devices with small floor space and flexible start-stop performance, mostly adopted for medium and small kilns, low-temperature flue gas and sites with space constraints.

5. Flue gas state and supporting equipment: Flue gas temperature drops sharply after wet desulfurization, and saturated water vapor easily forms white flue plume, which usually requires supporting facilities such as wet electrostatic precipitators and magnetic dewhitening equipment. The dry process causes slight temperature reduction of flue gas with negligible white plume, eliminating the need for complicated dewhitening supporting devices.

6. Operation cost: The wet process has low reagent consumption but high energy consumption of water pumps and agitators, and wastewater disposal raises operation expenses. The dry process consumes less equipment power yet requires much higher dosage of lime powder, leading to higher long-term reagent costs.