Single Drum Dryer Overview Manual
The single drum dryer is a new type of special drying equipment consisting of a heat source, a dispersing device, a belt feeder, a feeder, a rotary drum, a belt discharge machine, an induced draft fan, and an unloader.
The post will introduce some points on which should be payed more attention when choosing a single drum dryer.
What is the main applications of the single drum dryer?
The single drum dryer
1. Drying of coal slurry, raw coal, flotation fine coal, mixed fine coal and other materials in the coal industry
Coal slurry, raw coal and other coal materials have high humidity and cohesiveness that can not be dried by traditional dryer. But the single-cylinder dryer has a unique dispersing device to disperse the bonded coal slurry and then bake it, which increases the contact area between coal slime and hot air, greatly improving the heat utilization rate.
The single drum dryer can reduce the water of coal slurry to less than 12% at one time, then the dried slime can be directly used as fuel, turning the waste into treasure.
2. Drying of clay, bentonite, limestone, sand, quartz and other materials in the construction industry
Bentonite is a non-metallic mineral with montmorillonite as the main mineral component. It is a kind of clay rock that can be used in agriculture, light industry, cosmetics and pharmaceutical fields after drying. It can also be used as decolorizing agent, binder and touch, suspending agent, filling, feed, etc.
The single drum dryer can perform better and faster on such materials. During the process, the hot air flow is in full contact with the bentonite. The hing temperature and large drying strength make the moisture continuously evaporated in the cylinder body.
3. Drying of various metal concentrates, waste slag, tailings and other materials in the mineral processing industry
Under the situation of tight supply of global mineral resources, developed countries around the world have found that the remaining residues and tailings after the processing and utilization of mineral resources contain huge opportunities for secondary utilization.
The best choice for tailings dewatering - single drum dryer has become a necessary machine for drying tailings with advantages of large processing capacity, low energy consumption and saving labors.
The treated tailings moisture content is generally controlled below 10% or not more than 20%, which is convenient for transportation or transfer.
4. Drying of non-heat sensitive materials in the chemical industry
The non-heat sensitive material with moisture content of 15~17% is firstly dispersed by the special feeding device and then transported to the feeder by the belt feeding machine.
The wet material is conveyed by the feeding machine to the dryer drum. Under uniformly dispersing of the lifting plate device, the materials are fully contacted with the hot air for drying and mass transferring.
Why single drum dryer? - The comparison between single- and three-drum dryer
The comparison of the dryers
In the market, the rotary dryer can be divided into single drum dryer and three drum dryer, and the former is chosen by much more users because of its simple structure and small investment with large profit. In addition, we can find the exact answer through the following comparison.
1. Single drum dryer
- 1 The single drum dryer has lower water requirement (less than 50%);
- 2 It has features of compact structure, convenient installation, reliable operation, low energy consumption and high thermal efficiency;
- 3 It has high drying effect, and it is easy to realize automatic control with few operators;
- 4 The new-type internal structure strengthens the cleaning and heat conduction of the dispersed materials, eliminates the sticking phenomenon of the inner wall of the cylinder, and is more adaptable to the moisture and viscosity of the material.
The main disadvantage of the single drum dryer is that it occupies a long footprint.
2. Three drum dryer
- 1 The three-drum dryer is provided with three sleeve devices, which allows the material to be evenly dispersed inside the three drums, increasing the heat exchange area between the material and the heat transfer medium;
- 2 The heat transfer of materials and hot gases are carried out by means of reflux, so that the materials can contact with hot gases for a longer period of time;
- 3 The three-drum dryer is small in size and is only about half of the same capacity dryer.
- 1 Since inner cylinder space between sleeves is narrow, the behavior of the maintenance personnel is limited, which is inconvenient;
- 2 Since the support device between the sleeves determines the smooth operation of the entire cylinder, the production process of the equipment is relatively complicated, and the poor mastering will influence the stability of the equipment;
- 3 Because the multi-tube sleeves are together, the weighing ability of the support roll, the driving ring gear and the aperture need to be strengthened, which will cost more.
The process of the single drum dryer - Taking sand as an example
River sand is a relatively common building sand which has a very high water content and cannot be used when fishing out from river. It takes a certain period of time for the sand to dry naturally, which cannot meet the supply requirements of construction sand. The use of a single drum dryer can meet the using demand without the time and objective environment limits.
In the sand drying project, it has entered the following four working areas:
The process of sand drying
1. Feeding port
Wet sand in this area is in contact with high-temperature air to quickly evaporate water, and then copied through a lifting plate (to avoid sticking) and enter the next work area.
2. Dispersing area
Wet sand are dispersed in this area by means of a lifting device, which greatly increases the heat exchange area of the sand and hot air.
3. Inclined lifting plate area
The material is in full contact with the hot air, and the moisture in the wet sand rapidly evaporates to form water vapor, which is pumped away by the induced draft fan.
When the material falls, it occurs to bonding phenomenon, so the cleaning device is specially installed in this area; the loose sand with low moisture content after the heat exchange to achieve the required moisture state, finally entering the discharge port.
4. Discharge port
The drum does not have a lift board in this area, and the material slides to the discharge opening in this area to complete the whole drying process.
The choice of heating medium for single drum dryer
Single drum dryer on site
The use of a single drum dryer is inseparable from the use of a heating medium. Choosing a better heating medium can make the tumble dryer use better. So, how should it be chosen?
1. Hot fire furnace
If the solid material to be treated can stand high temperature, a hot air furnace can be used as the heat carrier, thus a higher volume evaporation rate and thermal efficiency can be obtained.
For example, for the drying of materials with high water content, when the gas inlet temperature is 300 degrees, the volume evaporation rate of the dryer is 5 kg/M3/h, and the thermal efficiency is 30%-50%. If the gas inlet temperature is 500 degrees, the volume evaporation rate is 35 kg/M3/h, and the thermal efficiency is 50%-70%.
2. Gas generator
If the treated material is not allowed to be contaminated with high required temperature, the gas generator can be used as a heating medium which has features of saving energy, environmental protection and high thermal efficiency.
If local environmental protection requirements are strict, it is best to use gas generators for saving energy and sanitation. The gas generator has at least 20% energy saving than the combustion furnace in terms of energy saving, and it also saves a lot in labor.
Generally, the gas generator only need one worker to operate, and does not need to be continuously added coal. It can be used for as long as 10 days, and you can continue to use it next time.
Under normal circumstances, hot air furnace is the choice of most users because of their simple structure, low investment and low heat loss.
Note: In addition to the choice of heat carrier, the main heat source, as well as fuel consumption is also a concern of users. Their usage can be calculated and screened according to the following formula.
Calculation of the volume of the heating material
1. The capacity X is known, feeding moisture is Y(%), discharge humidity is Z(%)
The total feeding amount of material W=X(1-Z)/(1-Y), the moisture evaporated by the dryer q=W-X
2. It is known that the heat required to evaporate 1t of water is 1 million kcal (10^6kcal)
Total heat required to dry the material: p=qx10^6kcal=(W-X)x10^6kcal
3. The heat generated by the unit heating material is known as m (ie the calorific value of the fuel)
Total heating material = p / m (without considering heat loss) = (W-X) x 10^6/ m
Fuel calorific values of different materials
Coal: 1 kg---5000 kcal
Gas: 1 m^3---8000-9000 kcal
Liquefied petroleum gas: 1 kg---12000 kcal
Diesel: 1 L---9180 kcal
Electricity: 1 kw---860 kcal
When drying sand, and it is assumed that the heating material is gas(1 m^3---8000-9000 kcal)
|Material||The capacity X||Feeding Humidity Y||Discharging Humidity X||The total volume of feeding materials W|
|Sand||90 t/h||20%||5%||106 t/h|
Therefore, the moisture evaporated by the single drum dryer: q=106-90=16 t.
2. So, p=16x10^6/m
3. The total required heating material = p/m(m=8000 kca) = 2000 m^3.
It can be seen from the above that if the sand capacity is 90 t/h, the feeding humidity is 20%, and the discharging humidity is 5%, and the desired gas consumption is 2000 m^3.
Fote Heavy Machinery focuses on the production of drying equipment, integrating research and development, production, installation, after-sales, staff training, technical guidance. The company has a complete and mature system and technology to produce single drum dryer with affordable and high quality, and it is choose by more and more overseas customers.
Fote Heavy Machinery(FTM)