Flue gas from thermal power, metallurgy, chemical, cement and other industries contains large quantities of SO₂. The wet flue gas desulfurization system (FGD) is standard equipment for emission compliance, energy conservation and carbon reduction. As the core power equipment of FGD, desulfurization pumps deliver corrosive solid-containing slurry and directly determine desulfurization efficiency and system stability.
Combined with industrial operation practices, this article elaborates on the core functions, working principles, structural design, performance parameters, operation & maintenance key points and industry trends of desulfurization pumps in a concise manner, helping readers quickly master core knowledge and solve problems in model selection and operation & maintenance.
A desulfurization pump is a special horizontal centrifugal pump with corrosion and abrasion resistance tailored for wet flue gas desulfurization (FGD) working conditions, a subcategory of industrial slurry pumps, fundamentally different from ordinary clean water pumps.
It mainly transports acidic media such as limestone slurry and gypsum slurry, which carry solid particles with strong corrosiveness and high abrasiveness. Therefore, desulfurization pumps are specially reinforced in material, hydraulic structure and sealing system to stably adapt to 24-hour continuous high-load industrial operation for a long term.
Common types include absorber circulation pumps, gypsum discharge pumps, filtrate pumps and desulfurization wastewater pumps, covering the full process of slurry circulation, slag discharge and wastewater treatment within the desulfurization system.
Indispensable core equipment for wet desulfurization systems, desulfurization pumps focus on three major aspects: desulfurization efficiency improvement, stable working conditions and environmental emission reduction.
1.Efficient desulfurization to guarantee exhaust gas compliance
It continuously delivers limestone absorbent slurry to the spray layers of the absorber, which neutralizes SO₂ and SO₃ in flue gas to generate gypsum precipitates. The desulfurization efficiency of the equipment can exceed 95%, lowering flue gas SO₂ concentration below 35 mg/Nm³ to meet strict domestic and international environmental standards.
2.Closed-loop circulation to stabilize system operation
Through the closed circulation mode of "slurry suction at tower bottom, top spraying and reaction backflow", flue gas and slurry maintain full and continuous contact to avoid fluctuations in desulfurization efficiency and ensure long-term stable operation of the complete system.
3.Energy conservation and carbon reduction for resource recovery
It cuts sulfide emissions at the source to reduce air pollution and help enterprises meet dual-carbon emission reduction targets. Meanwhile, it transports gypsum waste residue to dewatering equipment to realize solid waste recycling and lower enterprise operation and maintenance costs.
4.Working condition balancing to assist system operation & maintenance
It conveys desulfurization wastewater and dewatering filtrate to balance absorber liquid level, preventing shutdown and desulfurization failure caused by abnormal liquid levels and ensuring non-stop equipment operation.
5.Main Application Scenarios
Desulfurization pumps operate based on the centrifugal force principle of centrifugal pumps at a rotational speed of 1450~2900 r/min. They convert mechanical energy into fluid potential energy to realize continuous circulating delivery of slurry, divided into three overall stages:
1.Slurry Suction
The motor drives the impeller to rotate at high speed, forming a negative pressure zone at the impeller center. Under air pressure difference, slurry at the bottom of the desulfurization tower is continuously drawn into the pump chamber.
2.Energy Conversion
The impeller does work on slurry, endowing it with kinetic energy and pressure energy. After slurry flows through the volute, it decelerates and stabilizes pressure, converting kinetic energy into static pressure energy to form high-pressure fluid with conventional delivery head ranging from 10 m to 150 m.
3.Spraying Circulation and Reaction
High-pressure slurry is delivered through pipelines to the tower top for atomized spraying, fully neutralizing counter-flow high-temperature flue gas for desulfurization. Slurry generated after reaction flows back to the tower bottom and re-enters the pump body for circulation, forming a sustained closed-loop desulfurization process.
Principle Summary: Desulfurization pumps boost pressure and circulate slurry via centrifugal force, providing stable medium power for flue gas desulfurization reactions and serving as the core foundation for efficient operation of desulfurization systems.
Targeting the characteristics of corrosive, abrasive and clog-prone desulfurization media, desulfurization pumps adopt exclusive optimized designs with core advantages reflected in three aspects: materials, sealing and hydraulic structure.
1.Corrosion and Abrasion Resistant Flow Components
2.Dual Sealing Protection System
3.Anti-clogging High-efficiency Hydraulic Model
Adopts widened flow passage design to pass solid particles up to 20 mm, drastically reducing clogging probability, adapting to long-term delivery of high-solid-content slurry with lower energy consumption and higher efficiency.
Accurate parameter matching is the key to stable equipment operation. General core parameters widely adopted in the industry are as follows:
Standardized operation & maintenance can effectively extend equipment service life and stabilize desulfurization efficiency. Core operation & maintenance key points are listed below:
1.Daily Patrol Inspection
Strictly control operating indicators: bearing temperature ≤ 65℃, vibration value ≤ 4.5 mm/s; regularly clean 20~40 mesh inlet filters and prohibit pump dry running without slurry to avoid abrasion.
2.Periodic Maintenance
Inspect impeller wear every 3 months (allowable wear loss ≤ 3 mm); replace mechanical seals and NLGI Grade 2 lithium-based lubricating grease every year, and clear slag deposits inside the pump body.
3.Common Fault Troubleshooting
The desulfurization pump industry is iterating toward intelligence, long service life and energy efficiency:
Desulfurization pumps are fully adapted to harsh desulfurization working conditions, with core distinctions from ordinary clean water pumps as follows:
Relying on the centrifugal principle of centrifugal pumps, desulfurization pumps realize continuous suction, pressure boosting and closed-loop circulation of desulfurization slurry, serving as core equipment for industrial wet desulfurization systems. With exclusive corrosion and abrasion resistant structures and stable operating performance, they efficiently complete flue gas desulfurization and emission reduction to help enterprises conduct production in compliance with environmental regulations.
Desulfurization pumps with reasonable model selection and standardized operation & maintenance can effectively reduce equipment failure rates, extend service life and cut production costs, acting as key equipment for green production in heavy industries.
Q1: What pump category does a desulfurization pump belong to?
A: Desulfurization pumps are horizontal corrosion and abrasion resistant slurry centrifugal pumps, special industrial pumps for wet desulfurization systems, not applicable to ordinary clean water working conditions.
Q2: Can desulfurization pumps replace ordinary clean water pumps?
A: Technically feasible yet extremely cost-inefficient. Desulfurization pumps carry higher costs and are designed exclusively for slag slurry working conditions; using them for clean water delivery results in wasted performance and capital, so mixed use is not recommended.
Q3: What are the main causes of reduced flow rate of desulfurization pumps?
A: Primary causes include impeller abrasion, pipeline/filter clogging, excessively low tower bottom liquid level and over-high slurry solid content. Targeted clog removal, component replacement and working condition adjustment can restore performance.
Q4: What are the upper limits of temperature resistance and allowable solid content for desulfurization pumps?
A: Standard models withstand temperatures from -20℃ to 120℃, while customized models reach up to 180℃. Conventional pumps adapt to slurry with solid content ≤ 60%, and reinforced models can be customized for high-concentration working conditions.
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