This paper develops two optimal control models for the energy management of a mining crushing process based on jaw crushers. The performance index for both models is defined as the energy cost to be minimized by accounting for the time-of-use electricity tariff. The first model is referred to as a variable loadbased optimal control with the feeder speed and closed-side setting of the jaw crusher as control variables. The second model is the optimal switching control. From the simulation results, it is demonstrated that there is a potential of reducing the energy cost and energy consumption associated with the operation of jaw crushing stations in deep mines while meeting technical and operational constraints. Due to the inefficiency of the jaw crushing machine, whose noload power consumption is between 40 and 50% of its rated power, the optimal switching control technique is shown to be a better candidate in reducing both energy cost and consumption of the jaw crushing station. The benefit of having an ore pass with a big storage capacity is shown to be of great importance in achieving more energy cost reduction of the primary jaw crushing station while improving the switching frequency profile associated with the switching controller.
This work proposes a systems optimization control model for energy management of a parallel crushing process made up with high-pressure grinding rolls (HPGR) machines. The aim is to reduce both energy consumption and cost through optimal control of the process and load shifting, respectively. A case study of a copper crushing process is solved under three scenarios in order to evaluate the effectiveness of the developed model. Simulation results show that 41.93% energy cost saving is achieved through load shifting by coordinating the rotational speed of HPGRs. It is further shown that the energy saving can be achieved when the two HPGRs are not operated with equal overall efficiency, but also through a small decrement in rolls operating pressure. In the first case, 1.87% energy saving is obtained while in the last case, about 4.5% energy saving is achieved for every decrement of 0.2N/mm 2 in rolls operating pressure without significant change in product quality.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.