The effect of grindability upon nozzle pulverization

To determine the effect of the grindability of coal upon nozzle pulverization by running tests, in a small nozzle pulverizer unit, on various grindability coals from different coal seams in Virginia and West Virginia.

The authors want the reader to know that maximum pulverization was not the object of this test. The relative pulverization of the different coals was the goal to be obtained. In a more efficiently designed nozzle pulverizer unit with a better nozzle, higher pressure drop across the nozzle, and different coal-air ratios, greater coal pulverization can be obtained.

1. A small nozzle pulverizer unit can be built on which reproducible results may be obtained.
2. From the results obtained, grindability has an effect upon nozzle pulverization, but it is small over the range of Hardgrove Grindabilities studied.
3. The Hardgrove Grindability seemed to have less effect upon the per cent of fines produced than on the larger sized coal particles.