Wangpo Coal Preparation Plant′s existing coal blending system turned into an accurately controlled one through optimization

The problems with the use of traditional coal blending systems are low accuracy and reliability and delayed action, causing the blended coal product to fluctuate widely in quality. To deal with this situation, an optimized coal blending scheme capable of being accurately controlled is proposed. Through addition of ash meter and mixer, execution of electric gate position quantitative simulation and coal blending automatic control, as well as use of two coal washing systems, the coal blending operations can be made in an automatic and accurate manner. Practice shows that the system can maintain a stable operation; when raw coal remains normal in quality, the standard deviation of ash of coal before and after blending shows only a slight change while in the case that the raw coal is abnormal in quality, the said deviation is noticeably lowered from 2.25 before blending to 0.57; if raw coal quality deteriorates, and the ash of the blended coal cannot drop to the level as required with solely the clean small coal of the washing system A as the blend, the clean coal products of both washing systems can be used as blends for effective reduction of ash of blended coal product; with the use of the clean coal products from both systems as blends, the ash of blended product can be reduced from 27.09% to 25.03%, with the standard deviation decreasing from 1.81 to 0.84; while ensuring the required quality of blended coal , an optimized coal blending effect can be achieved; and 22,000 tons of clean coal can be saved per year, creating, as a result, an additional economic revenue of around 8.8 million yuan for the company. The use of the blending system can lead to upgrading of blended coal product and reduction waste of coal resource, allowing the coal resource to be utilized in a more rational manner.