Low-rank coal powder rotary drying technology with dust removing function

Abstract

The invention provides a low-rank coal powder rotary drying technology with a dust removing function. The low-rank coal powder rotary drying technology comprises the following steps: feeding coal powder of which the particle size is smaller than or equal to 30 mm into a rotary drying furnace; heating the coal powder to 80 to 280 DEG C for drying, so as to reduce the water content of coal powder to 0 to 5 percent; moreover, removing more than 85 percent of coal dust of which the particle size is smaller than 0.5 mm from the dried coal in the rotary drying furnace. Gas discharged from the rotary drying furnace contains coal dust; the coal dust is removed after the gas enters a gas dust remover; the coal dust-free gas enters a drying gas cooling system for temperature reduction; the cooled gas enters a blower for pressurization; the pressurized gas returns to the rotary drying furnace. After dust removing and drying, coal powder of which the particle size is 0.5 to 30 mm enters a downstream pyrolyzing furnace for pyrolyzing. Through the adoption of the technology, the dust content of coal powder entering into the downstream pyrolyzing furnace can be reduced; the yield of a coal tar product can be improved.

Description

Technical field [0001] The invention relates to a low-rank pulverized coal rotary drying process with dust removal, and is particularly suitable for the field of dry distillation and quality upgrading and drying of pulverized coal. Background technique [0002] Low-rank coal refers to low-quality coal with a low degree of coalification and a short coal age. According to coal types, it mainly includes lignite, long flame coal, weakly caking coal and non-caking coal. When this kind of coal burns, the flame is longer and smokey, the carbon content is 75-90%, and it does not contain free humic acid. Most of it has cohesiveness and most of it can coke. Common low-rank coal processing methods include direct combustion of low-rank coal for power generation, low-rank coal pyrolysis (ie, dry distillation of low-rank coal), and direct liquefaction of low-rank coal. Among them, the process of producing coal tar by dry distillation of low-rank coal and by-product pyrolysis gas and upgraded ...

AI Technical Summary

Problems solved by technology

[0005] In the prior art, the pretreatment of low-rank coal is usually to simply perform mechanical screening and particle size classification on raw coal. However, such a treatment method has little effect on the mechanical screening of pulverized coal below 3mm, and it is still in the industry at present. There is no simple and effective way to solve the technical problem of low-rank pulverized coal pyrolysis resulting in a large amount of coal dust in the product

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