Coal slime is the mineral coal with the lowest degree of coalification. A brown-black, dull low-rank coal between peat and bituminous coal. Because it is rich in volatiles, it burns easily and emits smoke. The traces of the original wood can be clearly seen on the section. Contains humic acid soluble in lye. The carbon content is 60% to 77%, the density is about 1.1-1.2, and the volatile content is greater than 40%. No glue layer thickness. The calorific value is about 23.0-27.2 MJ/kg (5500-6500 kcal/kg). Mostly brown or brown-black, with a relative density of 1.2 to 1.45.
Features of coal slime dryer
The coal slime dryer is designed for the characteristics that the initial moisture of blue carbon is higher than that of other materials, the specific gravity is smaller than that of other materials, and the fluidity changes greatly during the drying process. It has compact structure and less floor space, which is half of the floor space of single-cylinder drying with the same output. It has reliable operation, low energy consumption, high thermal efficiency, good material drying effect, easy to realize automatic control, and few operators. .
Working principle of coal slime dryer
Coal slime, fly ash, blue charcoal and other materials are sent to the feeder by the belt conveyor, and then the feeder transports the fly ash to the drying drum. , evenly dispersed and fully contacted with hot air to achieve the drying purpose of heat transfer and mass transfer. The dried fly ash is discharged through the unloader at the end of the drum, and the dry product is output by the belt discharge machine to complete the drying process.
Coal slime dryer process
The coal slime dryer uses a low-temperature four-stage drying process to evaporate the water content of the coal slime to less than 13% of the water content under the condition that the quality of the dried coal slime remains unchanged:
- The first-level drying zone removes most of the water at a high temperature of 400°C under high humidity to ensure that the chemical composition of the coal slime does not change and is not easy to burn;
- The room temperature of the secondary drying area is 300 ℃, and the high-yield water removal is carried out through the medium-temperature strong induced draft to ensure that the coal slime is not coked;
- The indoor temperature of the third-stage drying area is 120°C-210°C, and the crushing device in the drum is used to repeatedly impact and break up the materials, and then dry them downstream;
- The fourth-stage drying area is a high-exhaust area, with a room temperature of 60°C-80°C, and the water is removed by the low-temperature hot air flow with negative pressure in the induced air system.
The large chain ring cleaning chain is welded in the hopper of the coal slime dryer, which strengthens the cleaning effect and heat conduction effect of the chain on the dispersed material, and can effectively prevent the material from sticking inside and outside the lifting plate and on the inner wall of the drum.