Quality-improving process and apparatus for high-ash low rank coal

Abstract

The invention relates to a quality-improving process and apparatus for high-ash low rank coal and enables the problem that conventional quality-improving processes for low rank coal can only remove moisture but cannot remove ash to be overcome. The quality-improving process provided in the invention comprises the steps of primary drying for removal of external water in coal, secondary drying for removal of internal water in coal, dry cooling and removal of ash in cooled coal through winnowing so as to obtain high-quality coal. The apparatus provided in the invention comprises a drying system, a cooling system and a winnowing dedusting system. According to the invention, the advantages of a simple process, capacity of effectively removing water and ash, low production cost, low energy consumption and small investment for equipment are obtained.

Description

Technical field [0001] The invention relates to a coal upgrading process and device in the chemical industry, in particular to a high-ash low-rank coal upgrading process and device. Background technique [0002] China is a country with relatively abundant low-rank coal reserves. Most of the low-rank coal in my country has the characteristics of high moisture (about 30% by mass) and high ash content (about 20% by mass). Traditional low-rank coal quality improvement technologies are divided into two types: one is physical drying method, which only removes most of the moisture of low-rank coal; the other is dry pyrolysis method, which removes large amounts of coal through drying and pyrolysis processes. Part of moisture and volatile matter. Because these two low-rank coal upgrading technologies do not have the function of removing ash, the ash content in the upgraded product can be as high as 27-37%, which is equivalent to concentrating the ash in the raw coal into the solid upgrad...

AI Technical Summary

Problems solved by technology

But this method also has problems: (1) Although the drying effect is better after being crushed to coal powder, it brings the problem of separation difficulty after the flue gas and coal powder are mixed; (2) the separation process (such as cyclone separator or bag type Dust collector) is a gas-solid separation, which can only separate the tail gas from the pulverized coal, but cannot separate a large amount of dust contained in the pulverized coal, so that the above method does not have the effect of separating ash. Although the pulverized coal obtained in this way has a low water content, But the high ash content limits its scope of application

(3) To provide high-temperature flue gas with a temperature as high as 600-800°C, a separate high-temperature flue gas furnace needs to be installed, and the energy consumption is still high

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