Classified washing process for thermal coal

Abstract

The invention discloses a classified washing process for thermal coal. The classified washing process comprises the following steps that raw coal is screened to raw coal with three particle sizes of being more than 25mm, between 25mm and 13mm and less than 13mm, all raw coal with the particle sizes of being more than 25mm enters into a lump coal dense medium separation system, the separated lump clean coal and lump gangue enter into a lump coal dehydration and medium removal system for treatment and then output separately, and screened water enters into a slime water treatment system; and allraw coal with the particle sizes between 25mm and 13mm is directly transferred to a lump clean coal belt, the raw coal with the particle sizes of being less than 13mm is subjected to deep screening and pulverized coal removal, the raw coal with the particle sizes of being more than 6mm is transferred to the lump clean coal belt to be output, and slack coal with the particle sizes of being less than 6mm enters a slack coal bunker to be output. The raw coal is classified and then enters different separation processes for separation, the characteristics of low separation lower limit and high separation precision of a dense-medium shallow-groove separator are combined, and the classified washing process is particularly suitable for thermal coal preparation plants with fragile coal quality andstrict requirements for product granularity, has the advantages of simple process arrangement and low production cost, improves the quality of clean coal, and also guarantees the yield of lump coal.

Description

technical field [0001] The invention relates to the technical field of coal washing, in particular to a steam coal classification washing process. Background technique [0002] Among the proven coal reserves in my country, low metamorphic coal resources are the most, accounting for 57.4% of the total. With the continuous development of my country's coal industry, many large-scale coal fields dominated by lignite and long-flame coal have been developed. Some of the low-rank coals have the characteristics of low ash, low sulfur, high volatile content, etc., and have good reactivity and low price. Low advantage, it can be used as an ideal power coal and chemical raw material. Coal combustion will bring serious environmental problems. Therefore, it is the development requirement and trend of the coal industry to vigorously develop clean coal technology and promote efficient and clean utilization of coal resources. [0003] The quality-based utilization of coal is an effective w...

AI Technical Summary

Problems solved by technology

Among them, the lump coal gasification furnace has strict requirements on the particle size of the input material. If the particle size is too small, it is easy to be carried by the airflow to the outlet quickly, and there is no time to react. If the particle size is too large, it will easily sink to the bottom of the furnace and it is difficult to complete the reaction.

[0004] Steam coal preparation plants now mostly adopt the whole-stage washing process, which has flexible product structure adjustment, strong ash reduction ability, and is less affected by changes in coal quality. It can ensure the coal quality requirements of export steam coal and chemical coal; Suitable for thermal coal washing with friable coal quality and high clean coal particle size requirements

In addition, in the washing of a large amount of powdered coal, the dehydration effect of the slime is poor, and the calorific value is reduced due to high moisture content. Some coal preparation plants even have a phenomenon that the calorific value of the sorted product coal is lower than that of the raw coal.

In addition, when the slime is easy to slime, too much slime enters the sorting system, and the slime settles hard, which makes the slime content in the circulating water too high, which affects the sorting operation and the normal operation of the system, and reduces the economic benefits of the enterprise

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