Limestone Grinding Mill for Power Plant Flue Gas Desulfurization Systems

Limestone Grinding Mill for Power Plant Flue Gas Desulfurization Systems

Introduction to Flue Gas Desulfurization (FGD) Systems

Flue Gas Desulfurization (FGD) systems are critical environmental control technologies employed by power plants worldwide to reduce sulfur dioxide (SO₂) emissions from coal and oil combustion. Among various FGD technologies, wet limestone scrubbing remains the most widely adopted and effective method due to its high removal efficiency and cost-effectiveness. The core chemical reaction involves limestone (CaCO₃) reacting with SO₂ to form gypsum (CaSO₄·2H₂O). The efficiency of this process is heavily dependent on the quality and fineness of the limestone powder used, making the selection of an appropriate limestone grinding mill a paramount consideration for power plant operators.

The Critical Role of Limestone Grinding in FGD Efficiency

The dissolution rate of limestone in the scrubber slurry is a key rate-limiting step in the SO₂ absorption process. Finer limestone particles possess a significantly larger specific surface area, which dramatically accelerates the dissolution and reaction kinetics. This leads to higher SO₂ removal efficiency, reduced limestone consumption, and improved gypsum quality. Typically, FGD systems require limestone powder with a fineness of 90% passing 325 mesh (44 μm) or even finer, such as 250 mesh (D90). Inadequate grinding can result in unreacted limestone, which not only wastes reagent but can also lead to scaling and plugging in the scrubber, causing operational downtime and increased maintenance costs.

Key Parameters for FGD-Grade Limestone Powder:

Selecting the Optimal Grinding Mill for FGD Applications

Choosing the right grinding equipment is essential for achieving the desired fineness, capacity, and operational economy. The ideal mill must offer precise particle size control, high energy efficiency, reliable operation with minimal downtime, and compliance with environmental standards for noise and dust emissions. Several types of mills are available, each with its own set of advantages and operational ranges.

Comparison of Mill Types for FGD Limestone Preparation

Recommended Mill Solutions for FGD Systems

Based on the stringent requirements of modern power plant FGD systems, we highly recommend two of our flagship products, which are engineered to deliver superior performance, reliability, and cost savings.

1. SCM Series Ultrafine Mill (45-5μm) – For Maximum Reactivity

For power plants seeking the highest possible SO₂ removal efficiency and aiming to minimize limestone consumption, the SCM Ultrafine Mill is the ideal solution. This mill is capable of producing limestone powder with a fineness of 325-2500 mesh (D97 ≤ 5μm), which provides an exceptionally large surface area for rapid dissolution in the scrubber.

Key Advantages for FGD:

• High Efficiency & Energy Saving: With a capacity twice that of jet mills and energy consumption reduced by 30%, it significantly lowers operational costs.
• High-Precision Classification: Its vertical turbine classifier ensures a narrow and consistent particle size distribution (D97), eliminating coarse particles that could remain unreacted.
• Durable Design: Special material rollers and grinding rings extend service life, while the bearingless screw grinding chamber ensures stable, long-term operation crucial for continuous power plant operation.
• Environmental Compliance: The integrated pulse dust collector exceeds international standards, ensuring dust emissions are kept to an absolute minimum, while the soundproof room design maintains noise levels below 75dB.

Model Specification Highlight (SCM Series):

2. MTW Series Trapezium Mill (600-45μm) – For High-Capacity Reliability

For large-scale power plants with substantial limestone consumption, the MTW Series Trapezium Mill offers an outstanding balance of high capacity, reliable operation, and excellent fineness control. It is perfectly suited for producing the standard 325-mesh limestone powder required by most FGD systems.

Key Advantages for FGD:

• Anti-Wear Shovel Design: The combined shovel blade reduces maintenance costs, and the curved design extends the life of the grinding roller, ensuring consistent performance.
• Optimized Airflow Path: The curved air channel reduces energy loss and increases transmission efficiency, contributing to lower power consumption.
• Efficient Drive System: The bevel gear integral transmission achieves 98% transmission efficiency, saving space and installation costs.
• Durable Structure: The wear-resistant volute structure with a non-resistance design improves air selection efficiency and reduces maintenance costs by 30%.

Model Specification Highlight (MTW Series):

Conclusion

The selection and operation of a limestone grinding mill are pivotal to the success of a power plant’s Flue Gas Desulfurization system. Investing in advanced grinding technology like the SCM Ultrafine Mill or the MTW Series Trapezium Mill translates directly into enhanced SO₂ removal efficiency, reduced reagent and energy costs, improved system reliability, and full compliance with stringent environmental regulations. By focusing on the quality of the limestone powder, power plants can ensure their FGD systems operate at peak performance, contributing to cleaner air and more sustainable power generation.