Coal drying and upgrading method

Abstract

The invention is applicable to the technical fields of coal drying and coal dressing, and particularly relates to a coal drying and upgrading method. The method is mainly characterized in that a microwave drying system is used for drying raw coal, and a dry dressing system based on a sensor is used for separating out waste rocks or high-ash coal in the raw coal. The microwave drying has the advantages of high drying rate, energy saving, high production efficiency, uniform drying, clean production and favorable safety performance, is easy to realize automatic control, overcomes the problems of high coal burning possibility, high dust explosion possibility and the like in the high-temperature and medium-temperature drying process, and does not change the original property of the coal, thus being especially suitable for the drying of lignite, other metamorphic coal varieties, other high-activity coal varieties and other inflammable materials; and the dry dressing system avoids the use of a water source, solves the problem on coal separation in a water-deficient area, is compact in system structure and high in separation accuracy and efficiency, and has the advantages of low energy consumption, energy saving, environment friendliness and the like in comparison with traditional pneumatic coal separation. The invention organically combines the microwave drying system and the dry dressing system, and widens the application range, thereby being beneficial to the popularization of the coal upgrading technology.

Description

technical field [0001] The invention relates to a coal drying and upgrading method, which is used in the technical field of coal drying and coal preparation. Background technique [0002] my country's bituminous coal, anthracite and other high-quality coal resources have been fully utilized, and the expansion space is limited, while the large-scale development and utilization of lignite has just begun. my country's lignite resources are relatively rich, with a predicted resource of 190.3 billion tons, accounting for the national predicted coal resource. 41.18%. Young coals such as lignite and long-flame coal have the characteristics of high water content (20%~50%), low calorific value, high volatile matter, poor thermal stability, high chemical activity, and easy spontaneous combustion, making them difficult to transport, store, and sell. High water content in young coal directly increases transportation costs, device construction and operating costs, and even affects the no...

AI Technical Summary

Problems solved by technology

Wet coal preparation is a kind of coal preparation method in which water, resuspension or other liquid fluids are used as the separation medium. This method has been widely used, but gradually the amount of water is large, and the product needs to be dehydrated (or de-medium), dried and Subsequent treatment such as coal slime water and gangue treatment is required. The process is more complicated, the production cost is higher, and it is easy to cause coal slime water pollution. In addition, young coal types in my country are easy to muddy when exposed to water, so wet separation is not suitable; dry coal preparation Coal preparation method using air as the separation medium

This method requires low external moisture of raw coal, narrow grade of feed particle size, high lower limit of separation density and low efficiency, the separation effect is not as good as that of wet method, large working air volume, serious dust pollution of equipment, and small application range

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