Coal Powder Preparation Production Process and Equipment Selection

Coal Powder Preparation Production Process:

Modern coal powder preparation systems generally adopt a closed-loop process using vertical coal mills. The core concept is "integrated drying and grinding," resulting in a highly efficient and safe process. The specific steps are as follows:

1.Raw Coal Storage and Feeding:

Raw coal, after crushing (if necessary), is stored in a raw coal silo and continuously and stably fed into the vertical coal mill via a quantitative feeder (such as a belt scale or impeller feeder). Precise feeding is crucial for ensuring stable mill operation.

2.Drying and Grinding:

This is the core process. Hot air (approximately 200-300°C) from a hot blast stove (or cement kiln tail gas) is introduced into the vertical mill. Inside the mill, the hot air comes into full contact with the material, performing powerful drying while grinding, reducing the coal's moisture content to the target value (usually <1-2%).

3.Classification and Separation:

The ground and dried coal powder rises with the airflow to a dynamic classifier at the top of the mill. Coarse coal particles are returned to the grinding disc for regrinding by the classifier blades, while qualified fine coal particles (typically requiring a residue of <5-15% on an 80μm sieve, adjustable) are carried by the airflow to the next stage.

4.Collection and Storage:

The airflow carrying coal particles enters a high-concentration, explosion-proof baghouse dust collector. The dust collector efficiently separates and collects the coal particles from the airflow, which are then conveyed to a coal powder silo for storage via a screw conveyor and other equipment. The purified gas is discharged into the atmosphere by the main exhaust fan.

5.Conveying and Combustion:

The metering and conveying system (such as a rotor scale and screw pump) under the coal powder silo accurately and stably delivers the coal powder to the burners at the kiln head or furnace for combustion according to process requirements.

Key Equipment Selection:

Equipment selection directly determines the system's safety, energy consumption, stability, and finished product quality.

Main Unit: The Liming Heavy Industry vertical coal mill integrates drying, grinding, and classifying functions. Its power consumption is approximately 25-35% lower than traditional air-swept ball mills, and it has a smaller footprint and lower noise.

Dust Collection System: Explosion-proof pulse bag filter. Explosion-proof design is mandatory, including: anti-static filter bags, explosion-proof doors, pressure relief valves, and a nitrogen protection system (optional but crucial). Emission concentration must be <10mg/Nm³. Filter media material must be selected based on gas temperature (e.g., P84, fluoropolymer).

Main Exhaust Fan: High-pressure centrifugal fan, frequency converter control. Frequency converter speed regulation is essential to flexibly adjust system airflow, adapt to different coal qualities and production demands, and achieve energy savings.

Feeding Equipment: Sealed quantitative feeder to ensure uniform, stable, and metered feeding, and maintain negative pressure in the system to prevent hot air overflow.

Pulverized Coal Conveying: Rotary scale or loss-in-weight scale, requiring stable and accurate feeding to ensure stable kiln/furnace flame, which is crucial for improving combustion efficiency and quality.

Safety Core: CO-O₂online monitoring system, temperature monitoring, and inert gas extinguishing system to monitor the temperature of the hot air entering the mill and the O₂ and CO concentrations in the gas at the dust collector in real time. When the O₂ content exceeds the standard or the CO concentration rises sharply (indicating potential spontaneous combustion of pulverized coal), the system automatically alarms and initiates emergency measures (such as nitrogen purging).

The Liming Heavy Industry LM vertical coal mill integrates crushing, grinding, drying, and classifying processes through innovative process design, achieving efficient, safe, and environmentally friendly production from raw materials to finished products. The equipment is innovatively equipped with "five-level safety explosion-proof measures," providing comprehensive protection for the system's safe and stable operation.