rotary dryer

rotary dryer design & working principle

rotary dryer design & working principle

For evaporating moisture from concentrates or other products from plant operations, Rotary Dryers are designed and constructed for high efficiency and economy in fuel consumption.Whenever possible to apply heat direct to the material to be dried, Rotary Dryers of the Direct Heating Design are used. If it is not possible to apply heat direct to the material to be dried, Rotary Dryers of the Indirect Heating Design can be furnished so that the heated gases will not come in direct contact with the material.

Rotary Dryer is a simple, inexpensive unit for reducing the moisture content of flotation concentrates, as well as chemical and industrial products. Frequently the saving of shipping weight so effected will pay for the dryer in a few months. Difficulties from freezing while in transit are also eliminated. Many industrial projects are now using Dryers for control and production purposes on many materials.

Three main types of Rotary Dryers can be supplied. The direct heat unit is used when it is permissible for the drying gases to come in direct contact with the material being dried. Partition plates increase the heating surface. Drying may be by hot air or exhaust gases from other operations. If this drying gas has a deleterious effect on the product, then an indirect type of dryer can be supplied. A further derivation is the Tedrow Steam Dryer.

Of the different types of dryers that there are the most common is the ROTARY DRUM DRYER/Kiln, This type of drier is common not only in the mining industry but you will find them in fertilizer plants, Cement plants, and peat hogs to name but a few.

The theories behind these machines are very simple, heat an air space up, and then tumble the material to be dried through this space until it is dried. All though it sounds simple there are problems that have to be solved before the required results are met. But first, so you know what we are talking about lets go through the design of a drier.

First is the KILN, this provides the heat, The BURNER is inside this portion. The fuel for the burner is usually diesel although heavy crude oil could be used in some cases. To be able to generate enough heat to dry the concentrate air must be added by way of a BLOWER. In front of the kiln is the point that the wet concentrate enters the drier. It is put into the revolving SHELL. The shell is on a slight incline. As the Concentrate is tumbled through the hot air mass of the drier it travels down this incline to the exit of the drier.

At this exit point the concentrate is either deposited straight into a storage area or taken to the storage area by a conveyor. It is also at this point that there is an EXHAUST HOOD. This provides a controlled escape passage for the fumes and water vapor that is generated by the concentrate drying. This is a very important function and the operator will have to be sure that it is open at all times. If it should become blocked the water vapor will not be able to escape. The concentrate will become wet and sticky which will result in the discharge plugging. The wet sticky concentrate will also lower efficiency level of the drier for an extended period of time. This happens because inside the drier shell are what are termed FLIGHTS these are flat pieces of metal that are bolted onto the shell.

They are there to lift the concentrate up to the top of the shells rotation and drop the concentrate through the hot air. If the water vapor isnt taken away, the concentrate becomes sticky from reabsorbing the water. This sticky concentrate will fill the spaces between the flights.

The concentrate will not be lifted and dropped through the hot air. This results in a long term condition of poor performance even after the initial problem has been cured. These flights will remain buried in concentrate. This removal of the water vapor is one of the functions of the blower. It assists the natural process of air movement as the hot air mass expands. To prevent the buildup of concentrate on the flights there are often CHAINS attached to them. As the drier revolves the chains slap the flights preventing concentrate from building up on dryers walls.

The drier shell is rotated separately from the stationary kiln section. To achieve the rotation a BULL GEAR is attached around the shell section. There are also two flat rings attached to the shell. These provide surfaces for support rollers to roll on. There is another problem that the inclined shell has, the incline causes the shell to want to slide in the direction of the incline. To prevent this additional rollers are attached to the last set of rollers.

rotary dryer - fodamon machinery

rotary dryer - fodamon machinery

Rotary dryer(Drying Machine) is used for drying materials with a certain humidity or granularity in milling of ores, building materials, metallurgy and chemical industry. Gyro drying machinery has a strong adaptability of materials and it can dry various materials. The operation is very simple and liable. For this reason, it is used widely.

Rotary dryer(Drying Machine) is used for drying materials with a certain humidity or granularity in milling of ores, building materials, metallurgy and chemical industry. Gyro drying machinery has a strong adaptability of materials and it can dry various materials. The operation is very simple and liable. For this reason, it is used widely.

Materials are sent to hopper of rotary dryer by belt conveyor or bucket elevator.The barrel is installed with slope to horizontal line. Materials enter the barrel from the higher side, and hot air enters the barrel from the lower side, materials and hot air mix together. Materials go to the lower side by gravity when the barrel rotates. Lifters on the inner side of barrel lift materials up and down to make materials and hot air mix completely. So drying efficiency is improved.

Fodamon specializes in the production of large dryers, industrial dryers, etc., which are also called drum dryers, rotary dryers, etc. According to the different drying materials, they are also called cement dryers, slime dryers, sludge dryers, animal dung, bean dregs, palm dregs, desulfurization gypsum dryers, sand dryers, fly ash dryers, lignite dryers, etc. Dry mortar dryer and so on.

According to the different processing materials, it can be divided into talc dryer, kaolin dryer, lignite dryer, sludge dryer, sand dryer, river sand dryer, slag dryer, slime dryer, fly ash dryer, clay dryer, gypsum dryer, concentrate dryer, desulfurization dryer, etc.

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rotary dryer diagram - palet

rotary dryer diagram - palet

The three layers of drums are rotated at the same number of revolutions and the material direction is as follows: the wet material enters the inner drum, returns to the middle drum from the end, goes to the first end, then to the outer drum, and finally discharges from the end of the outer drum.

AB section: preheating section, the material through the scraper conveyor into the dryer, due to the role of high-temperature hot air makes the material heat up, reaching the wet ball temperature of the hot air, at this time the material moisture barely changes, the hot air temperature is slightly reduced, the heat emitted is mainly used for preheating the material.

BC section: equal speed drying section, the drying rate is constant, there is always a layer of free water on the surface of the material in this section, the heat transferred from the hot air to the material is all used for water vaporization. As a result, the temperature of the surface of the material always remains the same as the temperature of the wet ball of air, the temperature of the hot air and the moisture of the material is rapidly reduced.

CD section: Dry into deceleration section. The internal water diffusion rate of the material is less than the surface water vaporization rate, the material surface does not have enough water, so the drying rate is reduced.

The heat transferred from the air to the material is greater than the heat consumed by the vaporization of water, so the surface temperature of the material keeps increasing and the air temperature further decreases. If the material temperature reaches the level of insulation, the material temperature will coincide with the hot air temperature.

DE section: for the cooling section, the moisture content of the material has been reduced to the required value, discharged from the dryer, into the cooling system, through the cold air, so that the temperature of the dried material quickly slightly above room temperature, directly bagged and shipped out.

Adopt the following energy-saving measures.(1) New process for high temperature fast drying(2) Exhaust gas recycling: i.e., the exhaust gas (about 100C) is mostly returned to the blending chamber and heated again as a new drying medium.(3) High efficiency coal-fired hot air furnaceThe above measures resulted in a combined heat efficiency of over 76%(4) The installed capacity of the machine is only one-eighth that of a conventional drum dryer(5) Automation of the whole machine, saving the operator and thus greatly saving power.

Due to the use of high temperature rapid drying process, the material in the drying system, the flow time is only a few minutes, in order to ensure the quality of drying, when the moisture content of the wet material changes, the corresponding drying parameters must produce changes in line with it.

This change must be done by an automated control system. In this drying system, our company designed and manufactured a unique control method, first set the water content of the material after drying, in the drying process, regardless of the initial water content of the material and hot air temperature changes, the automatic control system will automatically adjust the corresponding parameters to ensure that the set water content of dry materials.

Qingdao palet machinery co,.ltd is a professional manufacturer of biomass wood pellet mill, wood pellet plant, rotary dryer, activated carbon rotary klin,activated carbon machine, hammer mill, crusher, etc.

complete rotary dryer design and calculation-palet

complete rotary dryer design and calculation-palet

Rotary DryerfromQingdao Palet Machinerycan reduce the biomass material moisture content from 40-55% to below 10% -15%, according to the customers request. How to choose the rotary dryer design for wood chips?Wehave finished a successful project for wood chips dryer in Malaysia.

Qingdao palet machinery co,.ltd is a professional manufacturer of biomass wood pellet mill, wood pellet plant, rotary dryer, activated carbon rotary klin,activated carbon machine, hammer mill, crusher, etc.

rotary dryers

rotary dryers

Weve built a reputation on building the best rotary dryers in the industry. All of our dryers are custom designed to suit the unique processing needs of your material. Whether you require low or high inlet temperatures, short or long residence times, counter current or co-current flow, FEECOs design team can design a rotary drum dryer for your application.

Rotary dryers are a highly efficient industrial drying option for bulk solids. They are often chosen for their robust processing capabilities and their ability to produce uniform results despite variance in feedstock.

The drum is positioned at a slight horizontal slope to allow gravity to assist in moving material through the drum. As the drum rotates, lifting flights pick up the material and drop it through the air stream in order to maximize heat transfer efficiency. When working with agglomerates, the tumbling action imparted by the dryer offers the added benefit of further rounding and polishing the granules.

All FEECO equipment and process systems can be outfitted with the latest in automation controls from Rockwell Automation. The unique combination of proprietary Rockwell Automation controls and software, combined with our extensive experience in process design and enhancements with hundreds of materials provides an unparalleled experience for customers seeking innovative process solutions and equipment.

Rotary dryers are known as the workhorse of industrial dryers. They are able to process a wide variety of materials, and can lend a hand in nearly any industry requiring industrial drying solutions. Some of the most common industries and materials in which rotary dryers are employed include:

Unlike direct dryers, indirect dryers do not rely on direct contact between the material and process gas to dry the material. Instead, the rotating drum is enclosed in a furnace, which is externally heated. Contact with the heated drum shell is what dries the material.

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Our rotary dryers are built to the highest quality standards, with longevity in mind. The best part about buying a FEECO rotary dryer, is that you get the security of knowing your equipment is backed by over 60 years of experience, material and process knowledge, and a proven track record.

rotary dryer: operating principle, classifications, uses, advanta

rotary dryer: operating principle, classifications, uses, advanta

The rotary dryer also known as tumbling dryer is an equipment employed to minimize the moisture content of feed materials by bringing it in direct contact with a heated gas. It consists of an inclined long drum or cylindrical shell often fitted with internal flights or lifters; rotated slowly upon bearings through which the material to be dried flow with a tumbling/cascading action in concurrent (for heat-sensitive materials) or counter-current flow with the heating air or gases.

The movement of the material is due to the combined effect of inclination of the shell to the horizontal and the internal tumbling action or mechanical turn over thus the name tumbling dryer. The nature of the feed determines the directions of gas flow through the cylinder and it is relative to the solid. This drying equipment can also perform batch or continuous processing of the wet feed.

A rotary dryer is said to be of the direct type if, by virtue of its design, heat is added to or removed from the solids by direct exchange between the gas and solids. The direct heat dryers are the simplest and the most economical class. They are used when direct contact with the hot gas or air is not detrimental to the fed.

When high temperature is required for the drying process in a direct-heated rotary dryer, a combustion chamber is used and when low temperature is required on the other hand, for thermolabile materials, steam coil is used.

Although there is an infinite variation of rotary dryers, which present characteristics suitable for drying, chemical reactions, mixing, solvent recovery, thermal decompositions, sintering and agglomeration of solids, the main types of rotary dryers include;

1. Excessive entrainment losses in the exist gas stream is possible especially if the material contains extremely fine particles due to the large gas volumes and high gas velocities that are usually required.

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