Читать книгу Coal-Fired Power Generation Handbook - James Speight G., James G. Speight - Страница 60

The rotary breaker essentially consists of an outer cylinder with an inner rotating perforated cylinder fitted with lifters which is operated at the lowest speed that will cause a small particle on the liner to centrifuge (Speight, 2013). Coal is fed into one end of the rotating cylinder where it breaks because of the tumbling action due to gravity fall, and pieces less than the hole sizes [typically 1% in. (38 mm)] pass out to a bottom collection trough, giving a product with positive upper size control. The flow rate through the breaker is adjusted so that pure coal has broken through and rock passes through the exit; in practice, some coal will pass out with the rock. Large pieces of hard, dense rock will also act as grinding media. Because of the relatively mild breakage action, the production of fines is minimized. For hard coal, the length-to-diameter ratio is increased, and the diameter is increased to give a higher force due to the greater fall.

The raw coal from the rotary breaker can be utilized directly, undergo further size reduction, or the quality of the product can be upgraded in a coal-washing facility (Speight, 2013).