What is flyash dryer?
In the coal-fired boiler system, the emission of coal ash can be divide into dry emission and wet emission. In the modern society, in the cement industry production, the dry coal ash can be as the admixture of cement, which has in short supply. However, the chemical characters of wet coal ash are same as the dry coal as, and the moisture content is large, which can up to 45% and not meet the requirements of cement plant. So it cannot meet the demands of market and just put in the storage bin to pollute environment.
Flyash dryer is a professional equipment for drying flyash particles. According to the flyash particles, it can be divided into the glass beads; spongy glass body (including the small particles, which has compact structure )and small pores and big particles, porous glass. The small beads content of the flyash, the most of ash is spongy glass body, whose particles is not equal. By the grinding process, it can destroy the raw materials’ structure to make the equal particles to improve the interface area, so that it can improve the surface activity and the difference of performance.
The flyash can be used as the admixture of cement, mortar and concrete, and it also is the composition of cement, concrete, the flyash can replace the raw materials of clay produces cement clinker, the making bricks, steam and gas concrete, foam concrete, hollow brick, sintering or non-sintering ceramic granule, paving road.
Constructing the dam, constructing the harbour, the farmland potholed lowland, the coal mine subsidence area and the mine backfill.
It can also be selected from bleaching, microbeads, iron powder, carbon, aluminum and other useful substances, among the beads can be used as insulation materials, refractory materials, plastics, rubber packing.
How to work?
There are some systems of the machine: the heating system, transportation system, drying system, dust removal system, silo and electric system.
When the hot air temperature up to the 350℃, under the PC system control, the equipment can work quickly. The wet materials conveyor can make the wet coal ash whose moisture content is less than 20% than can enter the feeding machine, the scattered feeding equipment has the two functions of scatter and conveyor which can make the materials enter the conveyor equally then enter the storage bin, through the spiral feeding machine to make the coal ash enter the drying cylinder equally. Compared with the traditional rotary drying machine, this type machine can save the energy by 1/3, which can greatly reduce the production cost.
The materials from the feeding device to enter the inside of three layers rotary cylinder to achieve the downstream dry. The materials will be lifted constantly by the lifting plate to do the spiral movement to achieve heating exchange. When the materials move to another end to enter the middle layer to be lifting repeatedly to do the counter current drying, which is marching into two steps forward and one back, so material in the middle is fully absorb heat coming from the inner cylinder, and absorb the middle roller heat and prolong the drying time again at the same time. It can dry material in the best condition.
Material to the middle at the other end and into the outer material within the outer cylinder rectangular loop travel more, to achieve the effect of drying in hot air under the action of moving fast discharge roller, did not achieve drying effect of wet material because of the weight can't advance rapidly, the material in this copy rectangular plate to fully dry, thus it can achieve drying effect to complete the whole drying process.
Wet coal ash and hot gas flow have been used as the heat transfer, the main way is convection and heat conduction, the way of radiation also has certain effect.
The three-layers roller structure is advantages to the time of stay in the equipment along the long material, which is to increase the heat exchange time, improve the thermal energy efficiency, and reduce the area of the equipment.
1. High drying rate. The final moisture content of the materials are less than 0.5%, which is the ideal equipment in the flyash or metal slag production line. Self-insulation thermal efficiency of cylinder can up to 80%( traditional single cylinder drying machine is only 35%), improved the thermal efficiency 45%, the fuel is suitable for the coal, oil, gas, which can dry the particles or bump materials whose size are less than 20mm.
2. Less occupation. Compared with the single cylinder dryer, this type dryer can reduce the occupation by 50%, the power consumption can reduce the 60%. The dryer adopts alloy steel materials to add the anti-wear rate of 4 times. It also can be adjusted the final moisture content in accordance with the requirements of customers.
3. Long service life and high quality final products. The temperature of outlet gas is low and the use life of the dust removal device is long. There are no need the rotation of gear to drive. It uses wet coal ash which features the high water content and low ratio. The traditional drying equipment cannot solve the problems of wet coal ash drying. Due to the wet materials will form a wind hole in the equipment to result in the hot gas short circuit,high waste gas temperature and heat loss is large.
4. Environmental protection. With the improvement of national government, it is necessary to turn the waste into treasure to get the good benefit of society and economy.