Energy-saving and environment-friendly drying method and device for coal slime and lignite

Abstract

The invention provides an energy-saving and environmentally-friendly drying method of coal slime and lignite, and comprises the steps that: air is heated by a heating furnace and is introduced to a drum dryer; the coal slime and lignite are discharged after performing heat transferring drying; high-temperature low-humidity hot gas is changed into medium-high-temperature high-humidity hot gas after being heat exchanged in a drying drum and is exhausted from the drum dryer, a large amount of dust coal in the hot gas is removed through a cyclone dust remover, the hot gas enters a first heat exchanger to cool, and is changed into medium-temperature high-humidity hot gas; the hot gas enters a heat pump unit after being cooled by the first heat exchanger, and is changed into low-temperature low-humidity hot gas after being cooled and removed dust; the hot gas is output from an outlet of the heat pump unit, and is changed into medium-temperature low-humidity hot gas through absorbing heat energy; and the hot gas is heated by a second heat exchanger and is changed into medium-high temperature low-humidity hot gas; and the hot gas is induced to the heating furnace for heating and is changed into high-temperature low-humidity hot gas. The device comprises a heating furnace, a drum dryer, a cyclone dust remover, a first heat exchanger, a heat pump unit including a dust removing cover anda second heat exchanger. The method and device provided by the invention have the advantages of efficiency, environment friendliness and good reliability.

Description

technical field [0001] The invention belongs to the technical field of coal and mineral drying, in particular to an energy-saving and environment-friendly drying method and device for coal slime and lignite. Background technique [0002] At present, the water content of coal slime after mining raw coal after water washing is about 30% after mechanical dehydration. The coal slime has fine particle size, high viscosity and low calorific value. There are about 40 million tons of such by-products in my country every year; lignite is produced in my country and China. There are huge reserves in the world, accounting for more than 30% of the total coal resources. Due to its water content of more than 30%, low calorific value, and high ash content, the annual output is hundreds of millions of tons; they must be removed to increase the calorific value. These coal slimes The chemical and physical composition is similar to lignite, and after dehydration and upgrading, the calorific value...

AI Technical Summary

Problems solved by technology

However, such energy-saving effect is only a limited use of the heat energy of the end exhaust gas.

When the production scale expands, domestic water and heat supply are very limited; especially when the temperature of the hot air flow at the outlet of the dryer is higher than 100°C, it is impossible to directly use the heat exchanger to recover heat energy and return it to the dryer, and a large amount of waste heat

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