The rotary dryer is a kind of industrial dryer employed to reduce or minimize the liquid moisture content of the material it is actually 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 from the solids by direct exchange between the gas and solids. The direct heat dryer would be the simplest and the most economical class.
They are utilized each time a direct contact with the new gas or air will not be detrimental towards the fed. When high temperature is required for rotary evaporator in a direct-heated rotary dryer, a combustion chamber can be used so when low temperature is needed on the contrary, for thermolabile materials, steam coil is used. Rotary dryer may also be reported to be indirect if the heating medium is separated from exposure to the solid by way of a metal wall or tube.
Single Shell Rotary Drum Dryer – The dryer consists of a large, rotating cylindrical tube, usually supported 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 to be able to convey the content through the dryer under gravity. Material to become dried enters the dryer, and because the dryer rotates, the material is lifted up by a series of internal fins lining the interior wall in the dryer. When the material gets sufficient to roll back away the fins, it falls down again to the bottom of the dryer, passing from the hot gas stream because it falls.
This gas stream either can be moving toward the discharge end from your feed end (referred to as co-current flow), or toward the feed end through the discharge end (known as counter-current flow). The gas stream can be made up of a blend of air and combustion gases coming from a burner, whereby the dryer is known as direct heated dryer. Alternatively, the gas stream may contain air or another (sometimes inert) gas which is preheated. When the gas stream is preheated by some means where burner combustion gases tend not to enter in the dryer, the dryer known as an indirect-heated type. Often, indirect heated dryers are used when product contamination is a concern. In some instances, a mix of direct-indirect heated rotary dryers can also be found to enhance the entire efficiency.
A rotary dryer is acceptable to dry metallic and nonmetallic mineral, clay in cement industrial and coal slime in coal mine, etc. Rotary dryers could be widely used to dry various materials, and are easy to operate.
Rotary Dryers have several applications but are most frequently observed in the mineral industry for drying sands, limestone, stones and soil, ores, fertilizers, wood chips, coal, iron sulphate, filter cakes, sewage sludge, etc. May 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 anymore than three drums is not usually necessary. Multiple drums is effective in reducing the quantity of space that the equipment consumes. Multi-shell dryers consist of several concentric tubes. Multiple shells enable 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. Because the material moves through the rotating drum is heated and moisture released. Some dryers offer an opportunity to cool, clean, shred, and separate the dried material.
For evaporating moisture from concentrates or any other products from plant operations, Rotary Dryers are made and constructed for high efficiency and economy in fuel consumption. Anytime you can to use heat direct towards the material to become dried, Rotary Dryers in the Direct Heating Design are used. If it is unachievable to apply heat direct towards the material to be dried, Rotary Dryers from the Indirect Heating Design can be furnished so that the heated gases will not are available in direct contact with the material.
Rotary Dryer is a simple, inexpensive unit for reducing 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 couple of months. Difficulties from freezing when in transit are also eliminated. Many industrial projects are actually using Dryers for control and production purposes on many materials.
Three main varieties of rotary evaporator may be supplied. The direct heat unit can be used when it is permissible for that drying gases in the future in direct connection with the fabric being dried. Partition plates increase the heating surface. Drying might be by hot air or exhaust gases off their operations. If this drying gas includes a deleterious effect on the product, then an indirect form of dryer can be supplied. A further derivation will be the Tedrow Steam Dryer.
The movement from the material is due to 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 nature in the feed determines the directions of gas flow from the cylinder and it is relative to the solid. This drying equipment could also perform batch or continuous processing of the wet feed.