A coal crushing and screening plant is an integrated industrial system designed to process raw coal into specified sizes for diverse applications, including power generation, metallurgy, and chemical industries. These plants ensure coal meets the granulometric and quality standards required for efficient combustion or industrial processing.

Operational Stages and Mechanisms:

  1. Preparatory Phase and Feeding:

    • Raw coal, extracted in large chunks (200-500 mm), is transported to the plant via dump trucks or conveyors.

    • Pre-Screening: Some plants use vibrating grizzly screens to separate smaller coal particles (0-50 mm) before crushing, optimizing energy consumption.

  2. Crushing Stages:

    • Primary Crushing (Jaw/Impact Crushers):

      • Jaw Crushers: Utilize compressive force between fixed and movable jaws to reduce coal from 200-500 mm to 100-200 mm.

      • Impact Crushers: Use high-speed rotors to shatter coal, ideal for medium-hardness and moist coal.

    • Secondary Crushing (Cone/Roll Crushers):

      • Cone Crushers: Crush coal between a rotating mantle and concave, producing 20-50 mm output.

      • Roll Crushers: Employ twin rollers to generate fine coal (0-10 mm) for specialized uses like pulverized coal injection (PCI).

    • Tertiary Crushing (Vertical Shaft Impactors): Used in advanced plants to produce ultra-fine coal (0-5 mm) for niche applications.

  3. Screening Process:

    • Multi-Deck Vibrating Screens: Separate crushed coal into categories:

      • Coal Dust (0-5 mm): Used in briquetting or fluidized bed combustion.

      • Fine Coal (5-30 mm): Optimal for thermal power plants.

      • Coarse Coal (30-50 mm): Suitable for coke production in blast furnaces.

    • Closed-Loop System: Oversized particles are recirculated to crushers, ensuring 95%+ efficiency.

  4. Dust Suppression and Environmental Compliance:

    • Wet Dust Control: Water spray systems at transfer points and crushers suppress airborne particles.

    • Baghouse Filters: Capture fine dust (PM2.5-PM10) to meet EPA/EU emission standards.

    • Enclosed Design: Modern plants feature enclosed conveyors and crushers to prevent fugitive dust.

  5. Storage and Logistics:

    • Stockpile Management: Coal is stored in segregated bays to prevent contamination.

    • Automated Dispatch: RFID-tagged trucks and weighbridges streamline loading and transportation.

Technological Innovations:

  • Predictive Maintenance: IoT sensors monitor crusher wear and screen efficiency, reducing downtime.

  • AI-Powered Optimization: Machine learning algorithms adjust crusher speed and feed rates in real time.

  • Renewable Integration: Solar-powered conveyors and rainwater harvesting enhance sustainability.

Economic and Environmental Impact:

  • Cost Efficiency: Uniform coal size reduces transportation costs by 10-15% due to higher bulk density.

  • Waste Valorization: Coal fines are repurposed for brick manufacturing or soil stabilization.

  • Carbon Footprint Reduction: Advanced filtration cuts CO2-equivalent emissions by 25-30%.