Coal Preparation » Process Control
This report describes a new type of online slurry ash analyser. The device calculates the density of particles in a slurry and makes use of the relationship between particle density and ash content. Particle density is measured by using a commercial online slurry density unit (Micro Motion Coriolis Meter) and a commercial online solids concentration meter (Markland 502-TP Suspended Solids Meter). The results from these two meters are combined to calculate the average particle density.
Experimental results showed that slurry density can be measured accurately, but accurate solids concentration results were more difficult to achieve. Comparison between online ash content and the laboratory results often displayed constant offsets. This could be explained by the fact that laboratory methods used to calculate slurry density and ash value do not allow for the effect of salt concentration or water temperature on density. A revised laboratory method for determining slurry density has been included in Appendix 1.
With the removal of the constant offset noted above, the online meter provides a reasonable determination of the current conditions in a particular slurry stream. The constant information gathered from the online meter can be used to accurately follow trends in particle density. Knowledge of particle density has been shown in this work to be sufficient enough to improve the control of flotation systems. The conversion from particle density to ash content simply provides a familiar term that one can relate to.
The application of this system is relevant to more than just the control of flotation systems. The use of this technology could extend into any application where a coal or any other slurry is measured.