Coal washing plant cyclone module control with a pump-storage system

A control system for coal beneficiation dense medium cyclone (DMC) circuit has been presented. The objective of the controller is to minimize energy consumption and the associated cost, and to maintain the quality of fine coal output from the DMC circuit to set level. The former is achieved largely by introducing a pump-storage system and the latter is reached by manipulating the density of the dense medium used in the DMC. The medium circulation, including magnetite recycling and water and make-up magnetite addition are modelled mathematically, according to which the control problem under consideration is formulated. A controller is designed to adjust the positions of two valves responsible for water and magnetite addition, respectively, according to sampled measurements on the composition percentages in the run-of-mine feed coal to the DMC circuit. Using operating data from a real mine, the effectiveness of the presented system is investigated and verified. It is shown that the designed system is able to maintain fine coal quality to a set level while remarkably reducing energy consumption of the coal preparation plant. In the studied case, an energy saving of 62.4%, which translates to 52.78GWh per annum is obtained. This reduced energy consumption then contributes to 5 446 896 US dollars cost savings for the plant per annum.