1. technical name

Industrial flue gas desulfurization, dust removal, deep purification and water recovery technology.

2. scope of application

Control of flue gas from coal-fired power plant boilers, steel sintering machines, and cement kilns in areas where water is short and temperatures are low all year round.

3. technical content

3.1 technical principle

The flue gas and the slurry generate a controllable turbulent space through the swirling coupling device, which improves the gas-liquid-solid three-phase mass transfer rate, completes first-stage desulfurization and dust removal, and simultaneously realizes rapid cooling and uniform flow field distribution; the flue gas continues to pass through the efficient spraying system to realize Deep removal of SO2 and secondary removal of dust; Flue gas enters the tube bundle type dust removal and mist removal device. Under the action of high-speed centrifugal force generated by cyclone separator, mist droplets and dust collide with each other during movement and condense into larger droplets. The droplets are thrown to the inner wall surface of the cylinder and captured by the liquid film layer attached to the wall surface, so as to realize deep removal of dust and mist droplets. A guide ring is arranged between the separators to improve the centrifugal movement speed of the airflow and maintain a proper airflow distribution state to control the thickness of the liquid film and the outlet state of the airflow and prevent the secondary entrainment of the liquid droplets. Saturated pure flue gas with ultra-low emission enters the cooling condensation section, and is subjected to intense gas-liquid contact and mixing with the cooling circulating water sprayed down through the cyclone coupling device layer to realize temperature reduction. The pure flue gas after temperature reduction continues to contact with liquid droplets in the spray layer, most of the fine liquid droplets are captured and fall down together with the spray liquid, and the rest fine liquid droplets are captured in the demister layer at the upper part, and a very small part is discharged along with the condensed clean flue gas. Cooling circulating water is heated in the cooling condensation tower, and a small amount of SO2, SO3, dust and gypsum droplets remaining in the clean flue gas at the outlet of the absorption tower are further removed. After the recovered circulating water and flue gas condensate are added to adjust the pH value, they are pumped to the air cooler by water pump to be cooled to 40 ° C, and then returned to the cooling condensation tower. The recovered condensate overflows into the recovered water tank for use in the desulfurization system or other water points. The working pressure of the spray layer nozzle should be 0.07Mpa, and the spray slurry droplet size at the nozzle outlet should be 0 - 2000μm.

3.2 main innovations

(1) Developed and applied an integrated flue gas desulfurization and water extraction tower to realize the integration of the two towers of the desulfurization tower and the condensation tower, and optimized the design of the gas lifting plate in the tower to achieve gas-liquid separation and water collection in the tower. (2) Developed efficient desulfurization and water pumping combined with ultra-clean flue gas treatment technology to further reduce the concentration of pollutants such as SO2 and soot. Under design conditions, SO2, NOx, soot, etc. are lower than the standards of gas units. The coordinated treatment of SO3 by flue gas desulfurization and water lifting has been realized, and the "blue smoke" effect in the chimney has been eliminated.

4. Pollution control or environmental restoration effects

Taking the 2×660MW coal-fired steam turbine generator unit project of Jingneng (Xilingol) Power Generation Co., Ltd. as an example, the SO2 concentration in the outlet flue gas is ≤10mg/m3, the particulate matter concentration is ≤5mg/m3, and the SO3 concentration is ≤ 0.08 mg/m3. The synchronous condensation recovery water volume is 100 t/h~120t/h, which can meet the water replenishment of production water in the plant area, and the power plant can achieve zero-water replenishment operation.

5. Technology demonstration

The 2×660MW coal-fired steam turbine generator unit of Jingneng (Xilingol) Power Generation Co., Ltd. is the first unit at home and abroad to apply this technology. The concentrations of SO2, particulate matter and SO3 in the outlet flue gas are far lower than the emission requirements of medium-fired gas turbine units in the "Emission Standards for Air Pollutants for Thermal Power Plants"(GB13223-2011). Flue gas recovered water is supplied to the water production workshop of the power plant to produce desalinated water, which meets the use of power generation production, and realizes zero-water replenishment operation for power generation of the power plant.

6. investment estimation

Taking the 2×660MW industrial flue gas desulfurization, dust removal and deep purification and recycling water project as an example, the total investment is 60.5631 million yuan.

7. investment recovery period

Taking the 2×660MW industrial flue gas desulfurization, dust removal and deep purification and recycling water project as an example, the static investment payback period is 6 years.

8. Prospects for transformation and promotion of technological achievements

This technology can be used in many industries such as electricity, heating, and petrochemicals. It is especially suitable for air pollution control in areas with fragile environments and scarce water resources, and has good application prospects.