The rotary dryer is a kind 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 reported to be of the direct type if by virtue of its design, heat is added to or taken off the solids by direct exchange between the gas and solids. The direct heat dryer are definitely the simplest and the most economical class.
They are utilised whenever a direct connection with the new gas or air will not be detrimental for the fed. When high temperature is necessary for rotary evaporator in a direct-heated rotary dryer, a combustion chamber is utilized and once low temperature is needed on the contrary, for thermolabile materials, steam coil can be used. Rotary dryer may also be reported to be indirect when the heating medium is separated from contact with the solid by a metal wall or tube.
Single Shell Rotary Drum Dryer – The dryer is comprised of a big, rotating cylindrical tube, usually maintained by concrete columns or steel beams. The dryer is inclined to slopes slightly so the discharge end is less compared to the material feed end to be able to convey the material from the dryer under gravity. Material to become dried enters the dryer, and as the dryer rotates, the material is lifted up by a series of internal fins lining the inner wall in the dryer. If the material gets sufficient to roll back away the fins, it falls back down to the foot of the dryer, passing through the hot gas stream since it falls.
This gas stream may either be moving toward the discharge end through the feed end (referred to as co-current flow), or toward the feed end from your discharge end (referred to as counter-current flow). The gas stream can be made up of a combination of air and combustion gases coming from a burner, in which case the dryer is named a direct heated dryer. Alternatively, the gas stream may consist of air or some other (sometimes inert) gas that is preheated. If the gas stream is preheated by some means where burner combustion gases usually do not go into the dryer, the dryer known as an indirect-heated type. Often, indirect heated dryers are used when product contamination is a concern. In some cases, a mix of direct-indirect heated rotary dryers can also be found to enhance the overall efficiency.
A rotary dryer is suitable to dry metallic and nonmetallic mineral, clay in cement industrial and coal slime in coal mine, etc. Rotary dryers can be popular to dry various materials, and therefore are simple to operate.
Rotary Dryers have several applications but are most commonly noticed in the mineral industry for drying sands, limestone, stones and soil, ores, fertilizers, wood chips, coal, iron sulphate, filter cakes, sewage sludge, etc. Can be applied to 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 one particular shell or many, though any more than three drums is not usually necessary. Multiple drums is able to reduce the amount of space that the equipment consumes. Multi-shell dryers contain several concentric tubes. Multiple shells allow the dryer to get utilized in a more compact space. The drums tend to be heated directly by oil or gas burners. The addition of a combustion chamber on the entry end helps ensure efficient fuel usage, and that homogenous drying air temperatures. Because the material moves through the rotating drum is heated and moisture released. Some dryers also provide the option 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 top efficiency and economy in fuel consumption. Whenever you can to utilize heat direct to the material to become dried, Rotary Dryers from the Direct Heating Design are employed. When it is not possible to apply heat direct for the material to be dried, Rotary Dryers in the Indirect Heating Design may be furnished so the heated gases is not going to come in direct exposure to the material.
Rotary Dryer is an easy, inexpensive unit for lowering the moisture content of flotation concentrates, along with chemical and industrial products. Frequently the saving of shipping weight so effected pays tjihbx the dryer in a month or two. Difficulties from freezing whilst 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 after it is permissible for the drying gases in the future in direct exposure to the material being dried. Partition plates increase the heating surface. Drying may be by hot air or exhaust gases off their operations. If this drying gas has a deleterious effect on the product, then an indirect type of dryer could be supplied. Another derivation is the Tedrow Steam Dryer.
The movement in the material is due to combined effect of inclination from the shell towards the horizontal as well as the internal tumbling action or mechanical turn over thus the name tumbling dryer. The character of the feed determines the directions of gas flow through the cylinder which is in accordance with the solid. This drying equipment may also perform batch or continuous processing of the wet feed.