Rotary Sand Dryers are divided into several categories according to the different types of sand, such as river sand dryers, silica sand dryers, dryers for mountain sand, sea sand and sand of casting applications, etc.. those different types of sand have different physical properties like sizes, moisture, etc.. and according to final their applications, they are always specific requirements for final dried sand. For example, silica sand for ceramic and glass industry, Iron is very sensitive in the material and cause coloring of final products, so stainless steel is used to avoid iron contamination. Meanwhile, same dryer may have different output capacity because different physical properties (see following chart).
Nowadays, our three-cylinder rotary dryers have completely replaced conventional rotary dryers in sand drying plants and they been proved to have many advantages.
1. Heat efficiency improved 40% more than conventional rotary dryers
2. Coal consumption (as fuel) is 30% of conventional dryers, less than 9kgs of coal to dry 1 ton of sand and power consumption is 60% of conventional dryers.
3. Output sand and outer shell temperature is no more than 60 C, exhaust air temperature is less than 120 C. filter bags can work twice longer time than conventional dryers, the output sand could be conveyed to warehouse directly without further cooling.
4. Airtight sealing avoids air leakage in conventional rotary dryers
5. Floor area requested for installation is 40% of conventional rotary dryers, saving 60% of infrastructure costs.
6. Output moisture could be guaranteed at 0.5% to 1% if input moisture is 15%, it is ideal choice for cements plants, dry mixed mortar plants, etc..
7. Heating source could be anthracite, bituminous coal, coal gangue, oil and gas. It could dry materials in lumps(size less than 40mm), granular and powdery materials.
8. Price is no more than 20% of similar equipment made in Europe. The barrel is made of manganese steel. Wear resistance is improved by 3 to 4 times.
Installation guide:
General Data of three cylinder rotary dryers drying different types of sand
Model | Capacity(t/h) | Output moisture | Coal consumption | Motor power | Weight | ||||
Mountain sand | River sand | Sea sand | Silica sand | Casting sand | |||||
DLS623 | 3-5 | 3-3.5 | 2.5-3 | 4-5 | 3-4 | <0.5 | 5-7 | 4 | 3.2 |
DLS625 | 5-6 | 4.5-5.8 | 4.5-5 | 5-7 | 5-6 | <0.5 | 5-7 | 5.5 | 5.1 |
DLS628 | 8-9 | 7.5-8.5 | 7-8 | 9-10 | 8.5-10 | <0.5 | 6-8 | 7.5 | 7.8 |
DLS6210 | 10-12 | 10-11 | 9-10 | 11-15 | 10-13 | <0.5 | 8-10 | 4×2 | 9.3 |
DLS6215 | 15-17 | 15-16 | 14-15 | 17-20 | 16-19 | <0.5 | 8-10 | 5.5×2 | 14.9 |
DLS6220 | 21-23 | 20-22 | 20-21 | 25-27 | 24-26 | <0.5 | 8-10 | 4×4 | 24.8 |
DLS6225 | 25-28 | 23-25 | 22-25 | 33-35 | 32-35 | <0.5 | 8-12 | 5.5×4 | 26.4 |
DLS6230 | 30-35 | 29-32 | 28-32 | 40-45 | 38-43 | <0.5 | 8-12 | 7.5×4 | 42.4 |
General information of Rotary Dryers
Rotary dryer is by far the most commonly encountered dryer in the mineral industry, rotary dryers are cylindrical drums normally supported on two or more tires running on a set of rollers at a slight incline to help convey the material. Wet feed enters the dryer through a feed chute, belt conveyor, screw conveyor, vibrating conveyor, or other suitable means. Drying air flows through the shell in either a co-current or countercurrent fashion. Lifters in the drum shower the material over the cross section of the shell to induce intimate contact with the drying air. Rotary dryers are very versatile and economic for large-tonnage drying of relatively low-value materials. In the mineral industry, they range from 1.5 to 4 m in diameter and are 6- to 30-m long. Evaporative capacities are of the order of 30 to 120 kg/h/m3 (dryer volume); thermal efficiencies range from 35 to 70%. Low capital costs, close quality control, low maintenance costs, and trouble-free operation over extended periods are some of the advantages of rotary dryers. Among the disadvantages are the difficulty of sealing, high structural load, and non-uniform residence times. For fine materials that tend to cause a dusting problem when dry, it is difficult to operate rotary dryers at high efficiency without more complicated mechanical modifications.
It is impossible to use one type of dryer for all applications. Pilot-plant tests and prior experience are the best guides in the selection of the proper type as well as the optimal operating conditions for the specific problem at hand. All elements of drying costs, namely, drying system (including pretreatment of feed and post-treatment of dry product), fuel, power, and maintenance costs, must be examined carefully before selecting the drying equipment. Efficient use of heat generally requires the control of entering- and exit-gas temperature and the control of the drying time to minimize heat losses. In the mineral industry, it is not common to use heat-recovery equipment even with modern installations. Maintenance costs are related to the first costs. Inadequate attention to mechanical and structural considerations, which may lower initial costs, may in the long run lead to higher maintenance costs.
For directly heated counter-flow or parallel-flow rotary dryers, the typical heat requirement for evaporation ranges from 670 to 1230 Kcal/Kg. For efficient operation, it is desirable to use the highest possible air temperature; in the mineral industry the normal range is 760 C to 980 C. For heat-sensitive materials, lower temperatures may be needed. For best heat transfer, it is necessary to use the highest possible air velocity; for dusty materials this poses a problem. For product moistures below 1%, a counter-flow dryer is recommended if the product is not heat-sensitive. For thermolabile materials with product moisture in excess of 1%, a parallel-flow dryer is desirable as the feed is in contact with hot gases while drying the surface moisture. The solid temperature does not exceed the corresponding wet-bulb temperature (corrected for radiation effects). For sticky or caking solids, which do not shower well, it is often necessary to allow more residence time in the dryer. New designs include special internals within the shell to break up the formation of large agglomerates in the drum so that a rotary dryer could be used to dry sticky or pastelike feeds.
Dryer loading may vary from 3 to 15%, of which 8 to 12% is the most common. This represents the volume occupied by the material within the dryer as a percentage of the total volume of the shell. Rotary dryers have a retention time of 5 to 25 min, with the normal range of 7 to 15 min. Dryer speed and inclination can be adjusted to attain the desired retention time for a given material.
1. Free consultation on technical &commercial issues, provide market evaluation, project feasibility based on each customers' condition.
2. Provide free drawings at no cost for factory layout, piping & wiring systems, installation plannings,
3. Free installation, commissioning and operation training services at no costs to customers.
4. 24/7 aftersales service, free of charge if repair service required within 1 year after installation.