Coal mill is a medium speed ball-and -race mill working on the ball bearing principle. The machine is manufactured in different size. The numeric specification on the equipment indicates the pitch circle of the balls in inches.
Most electric utility installations utilize the medium size. Our coal mills can provide outstanding mill performance when optimum operational and maintenance practices are adhered to. Optimum operation of the mill requires the following:
- Coal fineness of 75% passing 200 Mesh and <0.1% remaining on 50 Mesh. Coal mills that utilize ball bearing type grinding achieve very high 50 Mesh fineness much easier than other types of mills;
- A maximum imbalance of ±5% deviation from the mean dirty airflow between each mill’s separate fuel lines;
- A maximum imbalance ±10% deviation from the mean fuel flow between each mill’s separate fuel lines;
- Pipe to pipe clean air balance within ±2% of the mean pipe velocity;
- Air to fuel ratio of 1.75 to 1.8 pounds of air per pound of fuel;
- Pulverizer to mill mass air and fuel balance within ±5%;
- Pulverizer outlet temperature of 160°F or higher;
- Minimum fuel line velocity of 3,300 Fpm.
Coal grinding mill is designed with lower maintenance in mind. The components are arranged so that work can be performed through a single, large maintenance door. Specially designed tooling is provided with the grinding mill allowing a crew to handle grinding mill components efficiently and safely. The gearbox design permits easy removal without grinding mill tear down. With our grinding mill’s small footprint and large maintenance door, 360-degree access is not necessary, making it the perfect choice for both new and retrofit applications.