Study On Application Of Dry De-powdering Process In Pingshuo Coal Preparation Plant

In recent years,the proportion of thermal coal washing has increased significantly in China.At the same time,the main process of thermal coal separation is gradually formed by depulverizing,and the core of the whole process is the deep screening of fine particle size of raw coal.However,at present,there are many coal preparation plants due to improper selection of screening size,low screening efficiency and other problems,leading to prominent problems in the separation process of block coal,coal preparation plants low economic benefits.In this study,Pingshuo coal preparation plant as a typical,based on small for large,research suitable for China's steam coal raw coal fine depth screening process.This research has important guiding significance for improving thermal coal separation technology in China,improving coal resource recovery rate,reducing bulk solid waste(low-quality slime),and increasing economic benefits of enterprises.Based on the coal preparation plants of Pingshuo Group,the research of raw coal fine grained deep screening technology was carried out.By analyzing the existing coal preparation process,it is found that the raw coal 13 mm screening efficiency is low,which leads to the imbalance of the feeding amount of block coal system.It is proposed that improving the 13 mm classification efficiency is the key to balance the feeding amount of block coal system.At the same time,it is found that when the raw coal quality is good,the raw coal with particle size of 0mm?3 mm can meet the calorific requirement of the product,and it is necessary to depulverize the raw coal.Combined with the product market demand,through economic benefit calculation,it is found that the economic benefit of 3 mm depulverization of raw coal is the highest.And after comparing the advantages and disadvantages of the existing pulverizing equipment,it is determined that 13 mm grading and 3 mm pulverizing equipment are cross-screened.The coal preparation process is optimized as follows: 150-13 mm lump coal is mainly re-separated by heavy medium shallow groove separator,and 13-3 mm final coal is mainly re-separated by heavy medium cyclone.-3 mm pulverized coal can not only enter the heavy medium cyclone for separation,but also be mixed with products,and can also be partially selected and partially mixed with products.After the implementation of the project,the results show that the classification efficiency of 13 mm raw coal is 84.42%,and the pulverization efficiency of 3 mm is82.12%,reaching the expected effect.On the other hand,after 3 mm depulverization,the tail slime is significantly reduced compared with the non-depulverization process.After the depulverization process is adopted,the coarse coal slime in high quality steam coal decreases by 59.43% and the slime decreases by 66.39%.The slime in washing and blending coal decreased by 55.74%.Flexible realization of-3 mm powder coal can not only enter the production system,but also directly as a product;The addition of pulverizing technology does not affect the existing production technology of the coal preparation plant,but only complements and improves the flexibility of the existing process system.With the improvement of screening efficiency in 13 mm screening process,the content of slime in heavy medium suspension was significantly reduced.The mass coal system dielectric consumption decreased to 0.7kg/ ton;after 3 mm depulverization,the processing capacity of the final coal system is released,the processing capacity of the slime water system is also released,and the overall coal carrying capacity of the system is improved.Economic benefit accounting shows that:based on the single system of the main plant of Antai Bao coal preparation plant,which is 4 million tons/year,the total annual increase in income is 13.0215 million yuan,with significant economic benefits,while reducing the emission of bulk solid waste(lowquality coal slime)and significant social benefits.This study focuses on the existing core problems in the process of thermal coal pulverization,taking Pingshuo coal preparation plants as a typical example,to see the big from the small.According to the market demand of products,the quality of selected coal and the existing process problems are analyzed,the advantages and disadvantages of the existing pulverizing equipment are compared,the depth screening process of raw coal is studied,the optimized process is put forward,and the influence on the whole process is analyzed.This study has significant significance for improving the economic benefits of enterprises and creating social benefits.