Exploration and practice of reducing electricity cost in Sanxing Coal Preparation Plant

The equipment used in coal preparation operations are mostly large ones. Strengthening power management is, therefore, of vital importance for stabilizing power transmission, improving energy efficiency, and curtailing operating costs. The high cost of electricity incurred at Sanxing Coal Preparation Plant is attributed to the high unit consumption and high unit price of electricity. In order to tackle this problem, an analysis is made of the cost structure and the influencing factors causing the high cost of electricity. Based on result of analysis, and in line with the current national policy on reform of power system, a host of targeted measures is adopted by the plant. These include improvement of coal washing efficiency, reducing of time of shutdown caused by equipment failures, practice of fine management mode, arrangement of production to stagger the peak-load periods, and increase of power with reactive-load compensation equipment. Practice shows implementation of these measures has led to reduction of the total installed capacity of the plant to 2778 kW from previously 2794 kW; increase of raw coal treating capacity to 380 t/h from 280 t/h; cut of the time of shutdown caused by failure of equipment to one hour from 3 hours for every 100 hours of raw coal treated; rise of the share of the time period of coal washing operation at valley-load periods from 45% to around 60% of the total operating time; drop of power cost from 4.25 yuan to 2.79 yuan per ton of raw coal treated; and a save of electricity cost of 1.752 million yuan per year. The total input costs for implementing the above mentioned measures can be recouped in a period of 10 months.