The rotary dryer is a type of industrial dryer employed to reduce or minimize the liquid moisture content of the material it is handling by bringing it into direct contact with a heated gas. A rotary dryer is said to be of the direct type if by virtue of its design, heat is added to or taken from the solids by direct exchange between the gas and solids. The direct heat dryer would be the simplest as well as the most economical class.
They are used when a direct exposure to the hot gas or air is not detrimental to the fed. When high temperature is required for rotary evaporator in a direct-heated rotary dryer, a combustion chamber is utilized so when low temperature is required on the other hand, for thermolabile materials, steam coil is utilized. Rotary dryer may also be reported to be indirect when the heating medium is separated from contact with the solid by way of a metal wall or tube.
Single Shell Rotary Drum Dryer – The dryer consists of a big, rotating cylindrical tube, usually backed up by concrete columns or steel beams. The dryer is inclined to slopes slightly in order that the discharge end is lower compared to material feed end in order to convey the material from the dryer under gravity. Material to get dried enters the dryer, and because the dryer rotates, the content is lifted up by a series of internal fins lining the inner wall of the dryer. When the material gets sufficient to roll back off the fins, it falls back down to the bottom of the dryer, passing with the hot gas stream since it falls.
This gas stream may either be moving toward the discharge end through the feed end (known as co-current flow), or toward the feed end through the discharge end (referred to as counter-current flow). The gas stream can be created up of a mixture of air and combustion gases from the burner, whereby the dryer is named a direct heated dryer. Alternatively, the gas stream may consist of air or any other (sometimes inert) gas which is preheated. Once the gas stream is preheated by some means where burner combustion gases usually do not enter in the dryer, the dryer referred to as an indirect-heated type. Often, indirect heated dryers are utilized when product contamination is a concern. In some cases, a combination of direct-indirect heated rotary dryers are also offered to enhance the overall efficiency.
A rotary dryer would work to dry metallic and nonmetallic mineral, clay in cement industrial and coal slime in coal mine, etc. Rotary dryers could be commonly used to dry various materials, and are easy to operate.
Rotary Dryers have many applications but are most commonly seen in the mineral industry for drying sands, limestone, stones and soil, ores, fertilizers, wood chips, coal, iron sulphate, filter cakes, sewage sludge, etc. Can also be applied on food industry mainly for liquids as well as for granular material like food grains, cereals, pulses,coffee beans, fermented tea leaves, etc.
Drum or shell variations: Double Shell Rotary Drum Dryer. Triple Shell Rotary Drum Dryer – A rotary dryer can consist of a single shell or many, though any further than three drums is not usually necessary. Multiple drums is effective in reducing the volume of space that this equipment consumes. Multi-shell dryers include several concentric tubes. Multiple shells allow the dryer to be utilized in a more compact space. The drums are often heated directly by oil or gas burners. Incorporating a combustion chamber on the entry end helps ensure efficient fuel usage, which homogenous drying air temperatures. Since the material moves through the rotating drum is heated and moisture released. Some dryers also provide the choice to cool, clean, shred, or separate the dried material.
For evaporating moisture from concentrates or some other products from plant operations, Rotary Dryers are made and constructed for high efficiency and economy in fuel consumption. Whenever possible to utilize heat direct towards the material to become dried, Rotary Dryers in the Direct Heating Design are employed. When it is not possible to utilize heat direct for the material to become dried, Rotary Dryers of the Indirect Heating Design may be furnished in order that the heated gases will not are available in direct connection with the fabric.
Rotary Dryer is a straightforward, inexpensive unit for lowering the moisture content of flotation concentrates, in addition to chemical and industrial products. Frequently the saving of shipping weight so effected will probably pay tjihbx the dryer in a month or two. Difficulties from freezing while in transit will also be eliminated. Many industrial projects are now using Dryers for control and production purposes on many materials.
Three main kinds of rotary evaporator could be supplied. The direct heat unit can be used when it is permissible for your drying gases to come in direct exposure to the material being dried. Partition plates boost the heating surface. Drying might be by heat or exhaust gases using their company operations. If this type of drying gas includes a deleterious effect on the product, then an indirect form of dryer could be supplied. Another derivation is definitely the Tedrow Steam Dryer.
The movement of the material is because of combined effect of inclination of the shell towards the horizontal as well as the internal tumbling action or mechanical turn over thus the name tumbling dryer. The character in the feed determines the directions of gas flow from the cylinder which is in accordance with the solid. This drying equipment can also perform batch or continuous processing from the wet feed.