rotary dryer efficiency

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 saka

rotary dryer saka

Rotary Dryers are known for their robust construction. Rotary dryers are able achieve to very high temperature. SAKA offers wide range of Rotary Dryers that are designed to deliver best output, efficiently.

Rotary Dryers are one of the widely used Dryer in process industry. Especially in fertilizer and minerals industry for drying products such as coal, clay, gypsum, kaolin, limestone, mineral sand, potash, silica sand etc.

Rotary Dryers from SAKA provide controlled, uniform and efficient drying to help you achieve desired product quality. With a specialized design and sturdy construction our Rotary dryers are able to provide excellent thermal efficiency.

Rotary Dryers consist of cylindrical shell supported by riding rings to provide circular motion. These dryers come with lifter or flights on its inner circumference to lift and distribute material. These lifter also facilitates material movement towards final discharge point. Rotary dryers are always aligned on slight slope to facilitate movement of material from feeding point to discharge point under gravity.

SAKA employs highly advanced methodology of Computational Fluid Dynamics (CFD) analysis, to deliver guaranteed results for your Business, Process reliability and system performance. CFD simulation helps to foresee performance before actual execution of the systems, without actual installation of the system. It also helps understand the most vital parameters for improving performance.

The Co-current type Rotary Dryer is ideal for the materials that has tendency to stick and has high moisture content. Here Air and feed are introduced from the same direction and material comes in contact of hot air at its highest temperature,which instantly evaporates surface moisture.

The initial heat transfer rate is high, causing an immediate and considerable drop in gas temperature, which prevents overheating of the material and the dryer shell. The material which is in its final stage comes in contact of air/gas at its lowest temperature thus enabling the easy control over the moisture.

Directly Fired Calcinersare used for high temperature application. The process usually has longer resistance time, The length of diameter ration is often in excess of 10:1 to control the temperature along the length of the Calciner. Burner fires directly from the discharge end of the dryer.

In Indirectly Fired Calciner, material is heated with the help of the burners which are on the outer periphery of the dryer. Here, the heat is transferred by way of radiation and conduction through the cylinder wall.

The rotary drum is partially enclosed and externally heated by a series of burners mounted in an insulated stationary chamber or jacket. Ideal for materials which require medium or low temperature, Indirectly Fired Calciners are used for drying dusty, fine or heat sensitive materials.

Tube Bundle Dryers provide effective and efficient drying for materials which require lower drying temperatures. Main element of these type of Dryers are steam heated tube, it dries the product by rotating inside a firm housing. SAKAs Tube Bundle Dryers are highly efficient and require less warm air to dry the product thus there is less emission of air.

In Tube Bundle Dryers, feed comes in contact of heated tube and not directly heating medium. This makes is perfectly applicable for products which are free flowing and non sticky. Typically these Dryers are indirect type Dryer with counter current flow principle i.e. warm air flow in opposite direction of the feed.

Conduction dryer transfers the heat by contact of two surfaces the metal wall and heat jacketed vessel with agitator. Using electricity as source of energy, jackets are heated up, which transfers the heat to the drying surface leading to controlled drying of feed.

The Conduction Dryer comes with unique feature of sectional starting, which means you can heat up specific section of the Dryer giving very high quality product output, zero degradation of the product and excellent energy efficiency.

rotary dryers - an overview | sciencedirect topics

rotary dryers - an overview | sciencedirect topics

Rotary dryers are mainly used in the chemical and mineral industry. In the area of food, their most common applications are for dehydrating waste materials (citrus peels, vegetable trimmings) and animal feedstuffs (alfalfa). Rotary dryers consist of a metal cylinder with internal flights or louvers (Fig. 22.21). The cylinder is slightly inclined. The material is fed at the high end and discharged at the low end. Hot air is blown in cocurrent or countercurrent direction. As the cylinder rotates, the material climbs in the direction of rotation. When it reaches a position where its angle of repose has been exceeded, the material falls back to the bottom of the cylinder (Fig. 22.21). Most of the drying takes place while the material falls through the air blast. Using very hot air or combustion gases, rotary dryers can also function as roasters for nuts, sesame seeds, and cocoa beans. A detailed method for the design of rotary dryers, based on a heat exchange approach has been described by Nonhebel (1971).

Rotary dryers are often used for particulate material. Particles and hot air are continually fed to the drum. These large rotating drums have lifting flights which carry the particles upward as the drum rotates. The particles leave the lifting flight near the top of the drum and fall through the air stream. Heat is transferred to the particles both from the air and from contact with the dryer. The drums may have concentric sections so that the particles and air traverse the length of the drum up to three times. Residence time is on the order of minutes. Friable material, such as wafers or flakes, may be dried on trays or belts instead of in drums. Very fine material, such as fiber board furnish, might be dried in a tube dryer in which the air carries the fiber through the tube in seconds.

For particulate solids, a rotary dryer may help promote uniform and more rapid drying (Fig. 14.14). In the rotary cascade dryer, the material is placed in a rotating cylinder through which a hot air stream is passed. Flights on the cylinder wall lift and cascade the product through the air. In a variant, louvers are used instead of flights so that the product is mixed and rolled instead of dropped. The dryer is typically sloped, so that the product enters and gradually falls toward the discharge end. In direct rotary dryers, the air is passed through burners, and directly comingles with the product. Rotary dryers have been used to dry seeds, corn gluten, distillers grains, and some fruit.

A rice combine harvester usually performs with less loss of paddy; however, the potential shortcoming is that the paddy must be harvested at high moisture content, that is, ranging from 20% to 28%. The high moisture content of harvested paddy is conducive to rapid deterioration in quality such as discoloration, yellowing, germinating, and damage to milling quality.

The only practical means of preventing grain quality deterioration is immediate drying of high moisture paddy, because sun drying, the conventional method, is inadequate to guarantee the quality and quantity of the produce. Thus there is a high demand for mechanical drying facilities.

Most mechanical dryers available are suitable for rice millers and farm cooperatives that handle thousands of tons of paddy. Small-scale dryers were developed for farm use, such as a fixed bed dryer and solar rice dryer (Exell and Kornsakoo, 1977); however, those were not widely accepted because of the potential inconvenience in loading/unloading of paddy and unequal drying.

Jindal and Obaldo (1986) and Puechkamutr (1988) worked on accelerated drying of high moisture paddy using conduction heating for a rotary dryer. Their studies demonstrated the potential of high temperature for quick drying of paddy without significant damage to the grain. This technique is promising from an energy consumption point of view.

Puechkamutr (1985) developed a rotary dryer for paddy based on conduction and natural convection heating. Paddy was effectively dried from moisture content of 23% to 16% (w.b.) using a pipe heat exchanger at surface temperatures of 170C200C with a residence time of 3070s. Rapid drying and good milling quality of the paddy could be achieved with such a dryer.

A combination conductionconvection heating type rotary dryer was developed for on-farm drying as a first stage. It consisted of double cylinders: the external cylinder with 500mm diameter, attached to an inside surface with straight flight; and an inner cylinder, hexagonal in shape with an outer tray and firing device installed inside as a part of the inlet cylinder. The grain cascaded inside the external cylinder with a concurrent flow of air. Experimental results showed that about 3% of moisture content could be removed with single pass with a small reduction in milling quality (Likitrattanaporn, 1996).

Another study of a combined conductionconvection type rotary drum dryer was made by Regalado and Madamba (1997) on thermal efficiency. The fresh ambient air forced inside the drum in a counter flow direction of grain brought evaporative cooling of the hot grain as shown by the increase in moisture reduction whenever air velocity was increased.

A further improved prototype of a combined conductionconvection type rotary drum dryer used ambient air that was forced inside the drum in counter flow to the direction of the cascading grains. The grain was heated by conduction heating as drying proceeded and followed by convection heating as cooling occurred of the heated grain. The results showed that its partial drying capacity was approximately double that of the predryer developed by the International Rice Research Institute requiring only a single pass operation. Neither drum surface temperature nor ambient air velocity and their interaction influenced total milling recovery and head rice recovery.

Likitrattanaporn et al. (2003) designed and developed a combined conduction and convection heating rotary dryer for 0.5t/h capacity using liquefied petroleum gas (LPG) as the heat source, to dry high moisture paddy under farm conditions. The main aim was to find an affordable way of drying field paddy on the day of harvesting to facilitate handling and for higher returns of produce for the farmer. Emphasis was placed on operating conditions in which up to 3% moisture could be removed in a short time while grain quality should be closed to fresh paddy. Performance of the rotary dryer in terms of moisture removal, residence time, energy consumption, and milling quality were evaluated.

An experimental rotary dryer designed with concurrent flow system comprising two primary parts, a double cylinder and a discharge cover, is shown in Fig. 12.1. Forward movement of paddy takes place by inclination angle and rotary motion of the cylinder, while air is blown through the cylinder by the suction fan located on top of the discharge cover. A 1-hp motor with 1:60 reduction gear was used for driving the rotary dryer. The LPG lamp on the entry end heats up the air and heated air moves to other end by suction fan. During forward motion, paddy first contacts the outer surface of the inner cylinder where conduction heating takes place followed by a cascading action along the inside of the external cylinder resulting in convection heating. After this the paddy falls into the discharge cover and out of the dryer, while the suction fan sucks the moist air.

Relatively less moisture was removed during the last (third) pass at temperatures of 100C and 110C, that is, 1.5% and 1.7%, respectively. At 120C temperature, moisture content of 2.1% could be removed. Clearly, this is because there was less free water available at the third pass of drying.

The conduction and convection zones are shown in Fig. 12.2, along with the inlet and outlet temperatures of grain and the hot air. It can be seen that high temperature in the conduction zone can remove a higher amount of water than in the convection zone, which is, in turn, sucked out by hot moist air. It can also be observed that outlet grain temperature was dropped to the safe range (max. 52C) within a very short time (23min).

To demonstrate the dryers heat exchange efficiency, comparison of the effects of conduction heating and convection heating on moisture removal showed that the major moisture content of paddy was removed by the conduction heating for all temperatures, whereas the convection heating could remove moisture less than 0.4%.

Being designed as a mobile unit for drying paddy in the field, energy consumption is one of the most important aspects of consideration. The difference in weight before and after running a pass was recorded. A statistically insignificant difference was found in weight of LPG consumed at all temperatures. The average power consumption was, however, 0.6kWh and power of 0.46kg/h LPG. It was estimated that the operating cost of removing up to 1% of the moisture content of 1t of paddy was $0.23 in the first pass. The cost would increase up to $0.33 in the second pass and subsequently increase in the third pass depending on the availability of free moisture.

Likitrattanaporn et al. (2003) designed and developed a combined conduction and convection heating rotary dryer for 0.5ton hr1 capacity using liquefied petroleum gas (LPG) as the heat source, in order to dry high moisture paddy under farm conditions. The main aim was to find an affordable way of drying field paddy on the day of harvesting to facilitate handling and for higher returns of produce for the farmer. Emphasis was placed on operating conditions in which up to 3% moisture could be removed in a short time while grain quality should be closed to fresh paddy. Performance of the rotary dryer in terms of moisture removal, residence time, energy consumption, and milling quality were evaluated.

An experimental rotary dryer designed with concurrent flow system comprising two primary parts; a double cylinder and a discharge cover is shown in Figure 10.1. Forward movement of paddy takes place by inclination angle and rotary motion of the cylinder, while air is blown through the cylinder by the suction fan located on top of the discharge cover. A one horse power motor with 1:60 reduction gear was used for driving the rotary dryer. The LPG lamp on the entry end heats up the air and heated air moves to other end by suction fan. During forward motion, paddy first contacts the outer surface of the inner cylinder where conduction heating takes place followed by a cascading action along the inside of the external cylinder resulting in convection heating. After this the paddy falls into the discharge cover and out of the dryer, while the suction fan sucks the moist air.

Relatively less moisture was removed during the last (third) pass at temperatures of 100C and 110C, i.e. 1.5% and 1.7%, respectively. At 120C temperature, moisture content of 2.1% could be removed. Clearly, this is because there was less free water available at the third pass of drying.

The conduction and convection zones are shown in Figure 10.2, along with the inlet and outlet temperatures of grain and the hot air. It can be seen that high temperature in the conduction zone can remove a higher amount of water than in the convection zone which is, in turn, sucked out by hot moist air. It can also be observed that outlet grain temperature was dropped to the safe range (max. 52C) within a very short time (23min).

To demonstrate the dryers heat exchange efficiency, comparison of the effects of conduction heating and convection heating on moisture removal showed that the major moisture content of paddy was removed by the conduction heating for all temperatures, whereas the convection heating could remove moisture less than 0.4%.

Being designed as a mobile unit for drying paddy in the field, energy consumption is one of the most important aspects of consideration. The difference in weight before and after running a pass was recorded. A statistically insignificant difference was found in weight of LPG consumed at all temperatures. The average power consumption was, however, 0.6KWh and power of 0.46kg/hr LPG. It was estimated that the operating cost of removing up to 1% of the moisture content of 1 tonne of paddy was 0.23$ in the first pass. The cost would increase up to 0.33$ in the second pass, and subsequently increase in the third pass depending on the availability of free moisture.

Dried citrus peel is one of the most common feeds. It is manufactured by pressing peel through a rotary dryer and adding citrus molasses to help the drying process and help prevent the peel from burning. The moisture content of dried peel must be below 10%. Many experiments published in the 1970s have shown that dried orange pulp, partially or completely replacing cereals in concentrate mixtures, are particularly useful in reducing feeding costs in dairy cows, have no influence on production, and have a good palatability. Dried pulp has also been used in swine, which have been shown to utilize it at a ratio of up to 2025%. Besides its use as a substitute for maize, up to 20% in diet has no influence on the growth and production of laying hens. The dried pulp can be pelletized and is consumed more easily by ruminants with advantages of storage, shipping, and microbial spoilage. Pellets made from dried pulp have different dimensions, and several factors affect their characteristics, such as the energy used in pelletizing and the proportions of citrus molasses (about 515% of the total weight gives excellent results) used as binding agents.

Thermal desorption is a technology of physical separation based on heating the contaminated soil to volatilize water and organic contaminants. Soils are heated in a thermal desorption system, the rotary dryer being the most commonly used equipment. Thesystems require the treatment of the off-gas to remove particlesand contaminants. Its effectiveness depends on the contaminant. Decontaminated soil usually returns to the original site. Based on the operating temperature, these processes can be categorized into two groups: high-temperature thermal desorption ranging from 320 to 560C and low-temperature thermal desorption ranging from 90 to 320C. Thermal desorption can be used in a place where some other cleanup methods cannot be used, such as at sites that have a high soil contamination, and can be a soil remediation method that is faster than others.

Thermal methods may also be applied as an in situ technique. In this case, heat is applied to soil to volatilize semivolatile organic compounds (SVOCs), which can be extracted via collection wells and treated. It is a particular case of SVE. Heat can be introduced into the subsurface by electrical resistance heating, radio frequency heating, or injection of hot air or steam. Thermal methods can be particularly useful for dense nonaqueous phase liquids (DNAPLs) or light nonaqueous phase liquids (LNAPLs).

development of a high-efficiency rotary dryer for sewage sludge | springerlink

development of a high-efficiency rotary dryer for sewage sludge | springerlink

A rotary drum dryer having an internal rotating body was designed and tested in this study. It was shown that the developed dryer is effective for drying sewage sludge. The best operating conditions in the dryer were low energy input and almost 10% moisture content. The conditions are 255C for the rotary drum temperature, 17min for the sludge residence time, and 55kg/m3h for the dryer load. Under these conditions, the drying efficiency was 84.8%. The average diameter of dried sludge was less than 8mm, and the weight reduction rate was 80%. Parametric screening studies achieved the following results. The drying efficiency increased with the increase of the internal temperature and the sludge residence time in the rotary drum, while the drying efficiency decreased when increasing the dryer load. In addition, it was shown that NH3 and CO2 were the primary components released from the sewage sludge drying process. The amounts of both of these components increased when the rotary drum temperature was increased.

Deng W-Y, Yan J-H, Li X-D, Wang F, Lu S-Y, Chi Y, Cen K-F (2009) Measurement and simulation of the contact drying of sewage sludge in a Nara-type paddle dryer. Chem Eng Sci 64(24):51175124. doi:10.1016/j.ces.2009.08.015

Kim H-S, Shin M-S, Jang D-S, Na E-S (2005) A study for the thermal treatment of dehydrated sewage sludge with gas-agitated double screw type dryer. J Environ Sci Health A 40:203213. doi:10.1081/ESE-200038512

Deng W-Y, Yan J-H, Li X-D, Wang F, Zhu X-W, Lu S-Y, Cen K-F (2009) Emission characteristics of volatile compounds during sludges drying process. J Hazard Mater 162:186192. doi:10.1016/j.jhazmat.2008.05.022

Gonzlez JF, Romn S, Encinar JM, Martnez G (2009) Pyrolysis of various biomass residues and char utilization for the production of activated carbons. J Anal Appl Pyrolysis 85:134141. doi:10.1016/j.jaap.2008.11.035

Zhai YB, Liu Q, Zeng GM, Li CT, Yang F, Li SH (2008) Experimental study on the characteristics of sewage sludge pyrolysis under the low temperature conditions. Environ Eng Sci 25:12031212. doi:10.1089/ees.2007.0208

Inguanzo M, Domnguez A, Menndez JA, Blanco CG, Pis JJ (2002) On the pyrolysis of sewage sludge: the influence of pyrolysis conditions on solid, liquid and gas fractions. J Anal Appl Pyrolysis 63:209222. doi:10.1016/S0165-2370(01)00155-3

Shao J, Yan R, Chen H, Wang B, Lee DH, Liang DT (2008) Pyrolysis characteristics and kinetics of sewage sludge by thermogravimetry Fourier transform infrared analysis. Energy Fuels 22:3845. doi:10.1021/ef700287p

Chun, Y.N., Lim, M.S. & Yoshikawa, K. Development of a high-efficiency rotary dryer for sewage sludge. J Mater Cycles Waste Manag 14, 6573 (2012). https://doi.org/10.1007/s10163-012-0040-6

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.

maximizing rotary dryer performance with process audits

maximizing rotary dryer performance with process audits

The performance of a rotary dryer is vital to maximizing process efficiency and capacity in any industrial process setting. While a well-designed dryer will yield few problems of its own, various factors can cause the performance of the overall drying operation to degrade.

A process audit is a thorough inspection and analysis of rotary dryer operation. Unlike an equipment audit, which focuses on the mechanical and structural components of a rotary dryer, a process audit focuses on a dryers overall performance. Both the dryer and exhaust system are typically examined.

The most common reason for conducting a dryer process audit is to check and potentially improve fuel efficiency. An audit allows a process engineer to gather all the data and systematically determine how dryer efficiency could be improved.

It is often desirable to improve capacity without purchasing a new dryer. A dryer process audit will identify issues that are keeping the dryer from reaching its potential. With a dryer capacity increase, fuel efficiency will also often improve.

Flight/Lifter design is key to efficient dryer operation. The wrong type of lifter can result in build-up problems and poor showering. Often the design of the lifter changes along the length of the dryer because the material properties change.

In addition to the reasons listed above, process audits can also serve as a valuable opportunity to gather benchmark data. When conducted regularly, the analysis of benchmark data over time can reveal more subtle indications of a potential problem.

The most common reason a drying operation is experiencing issues is because of ambient air leakage. Air in-leakage can reduce the gas temperature at the dryer feed end, resulting in reduced capacity and higher fuel consumption. Leakage at the discharge end adds extra volume to the gas handling system.

Flight, or material lifter design has a significant impact on the end product and overall dryer performance. Flights must be designed around the characteristics of the feed material in order to yield optimal performance and results. If feed or process conditions change, flight design and pattern may need to be re-evaluated. If wet or sticky feed is consistently building up in the feed end of the dryer, for example, this may indicate that the lifter design is not appropriate for the feed.

Lifters are also the key to achieving higher dryer efficiency; by using the correct lifter design, including shape and size, the showering of material in the dryer can be improved, leading to better gas-to-solids contact and improved drying.

FEECO process audits begin with the Customer Service Engineer discussing the issues and goals of the process audit with the plants engineers and ideally, operators. Operators are typically most familiar with the process and material, making them a valuable resource in an audit. This initial discussion often provides a direction for the process audit, or gives the Customer Service Engineer an idea of where it might be best to start.

The Customer Service Engineer also requests all available operating data to be gathered for review. If a problem is not immediately visible, the engineer will begin by conducting a number of tests and measurements on the operational unit.

The Customer Service Engineer utilizes the data gathered during testing to systematically assess where an issue is originating. This starts by performing a heat & mass balance and checking the dryer operation against what is expected. Upon a thorough analysis, the Customer Service Engineer will provide a comprehensive audit report consisting of the data collected, a summary of the work that was carried out, and most importantly, recommendations to optimize the process or resolve any issues.

Making operational or equipment modifications identified by the Customer Service Engineer will help improve process performance. As a result, the following benefits may be observed (depending on the scenario):

Drying in an industrial process setting is integral to achieving the required product quality. A drying operation that is not running as designed can cause a variety of issues, and may originate from any number of sources. For this reason, rotary dryer process audits are an effective tool to improve process operation.

The FEECO Customer Service Team is highly experienced in dryer performance and can efficiently assess any drying operation for optimization and issue resolution. In addition to dryers, process and equipment audits are also available for rotary coolers, as well as agglomeration operations.

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