Coal Rotary Drying Solution
Coal (Wet Basis) from Coal storage yard or coal mine is loaded into belt conveyor and conveyed to sealing feeder for a direct fed into the JNG energy saving drum dryer. After undergoing a process of medium heat exchange drying, the coal is loaded into discharging conveyor belt from the discharging box. Then the coal is conveyed to THE storage yard.
Hot medium（hot fuel gas）for coal drying is produced and prepared in coal-fired hot blast heater. The environment air, which is sucked into the flue pipe with air blower and hot fuel gas from the hot blast furnace, is sent to drum dryer after temperature adjustment where it heats the wet coal and absorbs the water vapor. The mixture of hot gas and water vapor go through discharging box and flue pipe and is sent to dust collect cyclone for powdered coal recovery. The preliminary purified gas is sent to bag filter for further purification. Then the waste gas goes through the exhaust funnel and is discharged to the atmosphere by the induced draft fan.
The powdered coal collected by First Stage dust collector is loaded onto discharging conveyor by discharging spiral and sealed coal discharger, then mix with the dried coal. The powder coal collected from the second stage bag filter is loading into discharging conveyor by discharging spiral.
Take lignite coal for example
Features of lignite:
Lignite, also called brown coal, is the mineral coal with the lowest degree of coalification. It is a low-grade coal with brownish black like the color between peat and pitch coal, and unpolished. As it is rich in vdaf, it is easy to burn and smoke. The woody trace can be seen clearly from the section. The lignite contains humic acid that is soluble in alkali liquor. Its carbon content is 60%~77% and its density is about 1.1~1.2 and volatilization component is more than 40%.
Without thickness of colloidal matter layer, its heat value is about 23.0-27.2 MJ/kg (5500-6500 kilocalorie/kg). its color is brown or brown black with 1.2~1.45 relative density.
Technology of Lignite Dryer:
The previous drying adopts the centrifugal mechanical dehydration method whose equipment is expensive, output is low, and dehydration amplitude is small with 10% dehydration rate once and 15-20% moisture remains. The rotary lignite dryer adopts new technology of breaking and disperse the lignite before drying it by heat which realizes the serialization, industrialization, and automation of drying process. After the lignite drying fabrication processing, the moisture of the wet lignite decreases from 25%-30% to less than 13%. It can be used as fuel coal and has favorable economic, social and environmental benefit after perfecting the coal washing and screening techniques.
Working Principle of Lignite Dryer:
Rotary lignite dryer adopts low temperature four-stage drying techniques, making the lignite moisture evaporate to less than 13% with the lignite quality being changeless. The first stage drying area removes most moisture at high temperature of 400 centigrade degree on super wet condition to ensure the chemical component of lignite is the same and difficult to burn. The second stage drying area has a room temperature of 400 Celsius degree. Dehydrate by the medium temperature inducing air forcefully to ensure the lignite coking not. The third stage drying area’s room temperature is 120 Celsius degree to 210 Celsius degree. By the crushing plant in the rotary drum, the material is stricken repeatedly, dispersed, and dried in direct flow way. The fourth stage drying is high air exhausting area with room temperature of 60 Celsius degree to 80 Celsius degree. Dehydrate by the negative pressure low temperature hot current in the induced draft system.
Drum Coal Drying System
The drying machine is a rotary metal drum, which is set at an angle about 3-5 degree and rotates at a speed of 2-8 R/Min. The coal remains in the drum for 8-12min. The coal drum dryer are uniflow which mean the hot fuel gas and coal are fed in one end and discharged at the other. The heat exchange takes place during the process of gas-solids concurrent flow in the drum.
1. The process is simple and operation reliable. The factory is reasonably and compactly laid out as a whole with a combination of feeding,
crushing, drying and discharging. The total investment is low and service life is long.
2. The temperature of the heat transfer medium can be up to 600℃, and down to 100℃ when discharging. The drying thermal efficiency is high compared with other drying system.
3. The feeding quantity is adjustable with sealed coal feeder. The coal flows fluent and unblocked.
4. Measures are adopted to collect the dust and prevent the smoke at the drying drum, hot blast furnace and system transfer point. You will not see the air rebounded with dust and smoke
5. Automatic monitoring system can monitor temperature and pressure at four points: furnace, dryer inlet, and dryer outlet, inlet of induced draft fans which guarantee the normal and safe production.
6. Big volume drum dryer is adopted to shorten the residence time of coal in the dryer to prevent coal burning and pulverization.
Coal Drying Projects
| No. |
Project Item |
Notice |
| 1 |
Huaren county quanxi coal washing company |
|
| 2 |
Second Stage Drying Project of Henan Tianghong Coking Company |
|
| 3 |
Pingmei Group Chemical Limited Company |
|
| 4 |
Pingdingshan tanhong Coke Company Limited |
|
| 5 |
Xiaoyi Jinshui Coking Limited |
|
| 6 |
Pingdingshan Jingding Industry Co.,Ltd |
|
| 7 |
Pingdingshan Hongyao Coke Co.,Ltd |
|
| 8 |
Inner Mongolia Yidong Keyu High Technology Co., Ltd |
|
| 9 |
Handan Coal Prep Plant of Fengfeng Group |
|
| 10 |
Pingdingshan Huayang coal company |
|
| 11 |
Coal Chemical Branch of Datang International |
|
| 12 |
Jiaozuo Coal Chemical Group |
|
| 13 |
Coal Chemical Co.,Ltd of Inner Mongolia |
|
| 14 |
Shanxi Dayukou coal industry company |
|
In designing the drum dryer, we consider reliable performance, high capacity, high thermal efficiency, avoidance of caking, etc. In designing furnace, we consider easy ignition, quick heating, etc. In designing the dust collector, we chose deducting cyclone, which is high temperature resistant and without moving components, and high efficient pulse bag filter.
We have high technical strength and abundant work experience, which can assume technical and equipment design as well as provision of supporting equipments for coal drying system. It can also provide hot blast stove, dust collector, feeding and discharge machines as well as system auto monitoring equipments compatible with drying system. Owing to the adoption of new technologies, new techniques and new equipments, this system has a profound application in coal selection industry, chemical industry and coking industry both domestically and abroad, and has brought considerable economic and social benefits for its customers.
In recent years, the research office has abundant experiences through extensive efforts on the research of coal drying technologies, and has obtained numerous technological achievements and national-level patents of advanced international level.
Please provide the following information for a preliminary coal drying system design and quotation:
1. What is the particle size distribution of the raw coal? Please note that the coal fed into our drying system should be less than 50mm.
2. What are the requirements of drying capacity per hour and per annual? What is the local work system about working hours per shift and per day? How many days they work per annual?
3. What is the moisture content of the raw coal as received basis? What is the moisture content on air dried basis?
4. What is the lower heating value of the raw coal?
5. What is the requirement of the moisture content of the dried coal?
6. What is the local climate condition?
7. What's the coal type?
