Is Your Dryer in a Tight Spot?

Is Your Dryer in a Tight Spot?

We can build a sectionalized rotary dryer replacement with factory specs.

What can material processors do when their aged and worn rotary dryer needs replacing and yet, since it was originally installed, structural steel or even a complete building has been erected around it? Now that the dryer needs to be replaced, both the dryer and the owner-operator are in a tight spot!

Yet Louisville Dryer Company has provided several customers with the ideal solution for such challenging circumstances. We custom-build sectionalized replacement dryers that are produced and completely assembled in our factories, then disassembled and shipped to the customer’s site, and then rebuilt onsite by our team with exacting precision. The new sectionalized dryer replaces the old dryer that had been cut up and removed from ‘inside the bottle’ using heavy lifting equipment including gantry cranes.

How We do it.

The individual sections are designed and custom-manufactured by our dryer craftsmen:

  • They are assembled in our ASME facility typically using flanges with machined pin holes and dowels, disassembled, and shipped, and then precisely reassembled at the customer site..
  • Initial alignment is achieved using bolts through the flanges, and then further fine tuning is done using dial indicators before the sections are permanently welded together.
  • Precise sectional welding is another area where our expertise shines – as we maintain the specified shell runout and consider weld draw (distortion of the metal from welding).

The Louisville Dryer installation and commissioning teams ensure that the new unit and all related components are professionally installed, precisely balanced and optimally performing.

Some of our numerous projects for which we have provided Sectionalized Rotary Dryer Replacements.

a steam dryer being loaded onto a barge

For a minerals processor in California

A mineral company processing sodium sulfate had two direct heat dryers which were beyond their useful life cycle. The feed ends of the units were partially nested in a building and the dryers were surrounded by dust control and process equipment.
Louisville Dryer developed a plan to build each of the replacement dryer drums in three sections. Each section was flanged so that the drum could be completely assembled in our shop to hold to normal runouts. Once transported to the customer, the dryer sections were lifted into place and flange-mounted, then the sections were field welded. The result was a fully fabricated drum operating to factory specifications.

a steam dryer being loaded onto a barge

A sectional hastelloy dryer for an agricultural products processor in Illinois

a steam dryer being loaded onto a barge

For a Western region mining and refining company

a steam dryer being loaded onto a barge

Additional sectionalized dryer projects

Challenges of Building Sectionalized Dryers

Some of the engineering challenges of a sectionalized dryer solution include:

  • Design it with the fewest number of shell sections.
  • Avoid locating a welding seam in the middle of a tire or gear tube support.
  • Maintain the specified shell runout, taking into account weld draw.
an industrial dryer being transported down the river on a barge

Ideal Solution for Processing Companies
who are in a Tight Spot.

While sectionalized rotary replacement dryers are more expensive than monolithic rotary dryers, they can be designed to either match or exceed the production rate of the original dryer. And they can often serve as the ideal solution for material processing companies who require such design ingenuity to resolve their space limitations and equipment challenges.

As we have proven time and time again – and as confirmed by thousands of satisfied customers – Louisville Dryer Company is the team who can help you and your dryer get out of a tight spot.

Incinerating Waste To Produce Energy

Incinerating Waste To Produce Energy

Rotary Kilns
Many kilns, by definition, are refractory lined – using materials which are resistant to decomposition by heat, pressure or chemical attack. The refractory retains its strength and form at high temperatures.

Basically, rotary kilns are rotary shells that are insulated on the inside – which must be done with precise engineering, design and installation of the refractory bricks or other interior lining. Special focus must be placed on the critical relationship between the dryer shell and its rolling components.

a steam dryer being loaded onto a barge

Refractory used in rotary kilns prevent premature shell degradation from heat, pressure and chemical attack.

Refractory-lined kilns are designed to operate 24/7 because the primary factor which shortens their operating life is the thermal changes experienced from ambient temperature ramping up to 1000°F or 2000°F or more. Rotary kilns must be designed and operated carefully to gradually elevate their temperature and then stabilize it at a given rate for its production.

Louisville Dryer Rotary Kilns
Louisville Dryer Company provides both refractory lined Direct-Fired Kilns and Indirect Heat Kilns – often for incineration and gasification of petroleum sludges, biomass, or municipal solid waste. The process material is heated in the rotary unit and in a semi-inert gas stream. The complex organic molecules are converted to synthesis gas. This syngas is withdrawn to a secondary combustion system – ultimately converting waste to energy.

an industrial dryer being transported down the river on a barge

This Louisville Dryer rotary dryer kiln shell was recently custom designed to incinerate industrial process waste and convert it into energy.

For this custom application, the biosolids will be gasified from complex organic compounds into simple hydrocarbons – which will be extracted and then routed back into the burn chamber.

Dimensions and weight of this Rotary Dryer Kiln Shell custom engineered and manufactured by Louisville Dryer craftsmen are approximately:
• 14.5 ft. in diameter x 40 ft. in length
• 9” thick refractory lining
• 50,000 lb. tires (riding rings)
• 250,000 lb. dryer shell + 250,000 lb. refractory = approx. 500,000 lbs. total unit weight.

an industrial dryer being transported down the river on a barge

Once the refractory has been installed (on the inside of this kiln), approximately half a million pounds of steel and brick will rotate to the customer’s specifications with high accuracy and longevity.

To learn how Louisville Dryer applications engineers can custom-design, fabricate and install a long-lasting rotary kiln for your application, contact us today.

Should You Insulate Your Dryer/Kiln?

Should You Insulate Your Dryer/Kiln?

The Answer is a Definite – Maybe.

For Starters
A number of people in the process industry have highly recommended and promoted the idea of insulating dryers and kilns, even some that are already operating in the field. There is absolutely no simple answer as to whether dryers and kilns should be insulated. As with most industrial equipment, a well-founded and accurate answer for your specific component in your specific application would require a professional study of the metallurgical and thermal transfer aspects of operating your dryer/kiln while processing its full range of materials at its full spectrum of operating temperatures.

Optimizing Results for each Customer
Louisville Dryer Company and our affiliates have built over 5,000 dryers for all types of industries processing a wide array of materials, temperatures, and production rates. Most every dryer/kiln is custom-designed and evaluated in our own fabrication facilities even though many of them are going to be commissioned within the same industry – as some will be operating in slightly different conditions.

a steam dryer being loaded onto a barge

Based on Louisville Dryer’s 120+ years of corporate legacy and solution-providing experience, we have honed best practices and procedures for calculating and projecting each unit’s performance longevity. We take pride in earning and continually maintaining the industry designation as providing rotary dryers and drums with The Lowest Cost per Revolution.

Precision Dryer Testing Laboratory
Our applications engineers indicate that the best way to confirm optimal results for a unit is through material testing. We have in own test laboratories multiple scale models and designs of test dryers, and operator-engineers with experience in precision testing.

To facilitate accurate test runs, we request that the processor or end-user send samples of their actual material(s) to be processed, which will be precisely measured and run under careful controls in the Louisville Dryer test lab unit. The test dryers are of the same design as full-scale in-production unit; they are just scaled-down versions.

Precision Dryer Testing Laboratory
Our applications engineers indicate that the best way to confirm optimal results for a unit is through material testing. We have in own test laboratories multiple scale models and designs of test dryers, and operator-engineers with experience in precision testing.

To facilitate accurate test runs, we request that the processor or end-user send samples of their actual material(s) to be processed, which will be precisely measured and run under careful controls in the Louisville Dryer test lab unit. The test dryers are of the same design as full-scale in-production unit; they are just scaled-down versions.

an industrial dryer being transported down the river on a barge

Louisville Dryer testing units include both direct-fired dryers (both in co-current and counter-current airflow patterns) and direct-heat dryers (where the source of hot gases is generated external to the units). Our lab also houses scaled rotary steam tube dryers – which can operate under a variety of steam temperatures and pressures and adjusted to very precisely remove moisture down to one-tenth of one percent.

Our test lab also operates indirect heat models where the heat is supplied on the external shell from multiple burner-firing positions. Having scale models of the full range of dryers is an important contribution toward our custom-design, fabrication and maintenance of full-scale units for very specific and demanding applications – considering all requirements of the material to be produced, moisture to be removed, temperature needed to effectively yet safely process the customer’s materials, and more.

Over the decades Louisville Dryer Company has precision-tested numerous various materials and have catalogued the results, amassing a valuable source of performance information. And we still regularly test new combinations of materials and operating conditions since some processors want to do more than dry their materials, but also change the state or phase of material and/or combine ingredients to create a new product.

Custom Design of Every Dryer/Kiln
As our engineers step through the custom design process, they consider multiple operating factors including the angle of repose of the material, the amount of lifting material and if there is degradation by the veiling, the length of time in-process needed to remove either external or internal moisture of material, production rate, the amount and type of emissions (both particulate and products of combustion which may exit the rotary drying unit).

a steam dryer in transport along a railway

To Insulate or Not to Insulate

Rotary Kilns
Toward answering this frequently posed question, an initial differentiation is made between rotary dryers and rotary kilns. In general, many kilns, by definition, are refractory lined. Basically, the unit is insulated on the inside of the rotary shell, which must be done with a great deal of precise engineering, design and installation of the refractory brick or interior lining of the kiln.

Additional considerations must be made for kilns which need to be fabricated with less common materials or for those which will be processing end-user materials that require a high-heat input in at least a portion of the unit and, perhaps, cooling in the longer shell section.

Most of the refractory-lined kilns are designed to operate 24 hours a day/7 days a week because the factor which shortens their operating life more than anything is the thermal changes experienced from ambient temperature ramping up to 1000°F or 2000°F or more. Thus, they have to be designed and operated carefully to gradually elevate their temperature and then stabilize it at a given rate for its production materials.

replacement dryer being installed by louisville dryer company crew

Rotary Dryers
Generally speaking, rotary drying units which process materials at a lower temperature and at a constant 24/7 production are often better candidates for insulation. Of course, the insulating of rotary dryers yields lower savings than with rotary kilns because, with rotary dryers, there is less loss of shell heat from drying operations at lower temperatures.

The insulation decision become more complex when evaluating drying units with operating temperatures between those of the typical rotary kiln and rotary dryer. The drying units in this medial range are the ones which, perhaps, need to elevate material up to several hundred degrees Fahrenheit and then operate in a start-and-stop mode.

Such units which operate at these higher temperature ranges tend to affect the performance of the internal flighting, dams or baffling as the entire rotary cylinder heats and expands during processing. The rate of expansion of this rotary cylinder is very critical and will dramatically impact the entire life of the drying unit.

Furthermore, if the process is subject to stops and starts daily, or even multiple times a day, those operations also can create internal corrosion in the internal shell and dramatic corrosion between the external shell and any layer of insulating materials.

Again, perhaps there are some BTU savings of energy loss from the external of the shell, but this cost-wise is more than compensated for based on shortening the life and vastly increasing the chances for frequent maintenance of the entire shell, supporting tires, circumferential tires, support rollers and trunnions, the drive gear, the support pads and structures for the tires and gear, seal systems and many other factors.

If the calculations are not made precisely, the gap between the dryer/kiln when it’s heated up will have a lot of slack, what’s known as ‘creep’, and the unit will tend to wear in an irregular pattern and shorten the life of the tire-mounting and can also affect the carrier rolls/trunnions and the drive system.
Likewise, if the unit is not engineered correctly and the thermal expansion of the rotating shell presses into the tires too much, the result can crush the shell and then cause cracking, dents, and many other problems in the process.

With these real concerns in mind, one of the functions which our Louisville Dyer engineers perform in many heavy-duty design rotary units is an FEA (Finite Element Analysis) to measure and evaluate many of those factors. This process will then help them determine if insulation should be used on the shell or some portion of the unit.

Insulation of New Custom-Designed Dryers vs. Existing Rotary Dryers/Kilns vs. Used/Repurposed Rotary Dryers/Kilns:
Our engineers report that, once they have done the relevant testing and evaluation of new custom-designed dryers and considering the production and temperature ranges and other relevant factors, it is sometimes appropriate to insulate certain rotary dryer unit. While, on the other hand, it is often at great peril to plant/production facility when operator-owners choose to insulate an existing dryer or used/repurposed units without first employing proper testing.

replacement dryer being installed by louisville dryer company crew

One relevant example shown here is a rotary drying unit which is a very efficient rotary aggregate dryer. The input of its ambient material may be as low as 40°F, while the unit commonly processes and elevates the exit temperature of the material to over 850°F. What is remarkable is that the exit gas temperature going to the air pollution equipment is only around 280°F.

replacement dryer being installed by louisville dryer company crew

This case is a very efficient heat transfer rotary process. And it would absolutely be the worst candidate for insulating the rotary shell. The operation starts and stops multiple times every day. Since the shell frequently expands and contracts, were it to be insulated there would be great potential for corrosion and more rapid wear.

What would be even more severe for this case would be the cracking of the shell or compression of the shell by the tires if there was not ample design in the process for shell expansion. Another issue would be that the temperature on the shell on the burner end would be hundreds of degrees more than the shell on the intake material feed end.

So, the quandary would be trying to insulate its various sections differently: first a 20 ft, section with a certain amount/type, then a 27 ft. section with a different amount/type, and then none. This approach to shell insulation could not provide dependable nor desirable results.

replacement dryer being installed by louisville dryer company crew

Then, of course, there are several fly-by-night brokers or even scam artists who claim that virtually any rotary unit can be used to process most any material. They claim that a nominal rotary drying unit can be purposed for six or eight different types of material, at all temperatures, for all production rates – which is certainly misleading and, in many cases, fraudulent.

The Bottom Line
Insulation of a rotary drying unit can be acceptable when all the design and operation factors are tested and evaluated before custom-building the unit.

To learn more details about dryer/kiln insulation, or to request information on our custom dryer designs, contact us at 800-396-6365 and

Why Build a Seal Test Assembly?

Why Build a Seal Test Assembly?

When a customer requested our advice on the most effective long-lasting seal technology for steam tube dryers in petrochemical applications, our application engineers designed and ran a Seal Test Assembly to generate live test data to inform and confirm their recommendations.

To gather relevant data in a controlled environment, our engineers and fabricators built a scale-model steam tube dryer seal assembly in our own test lab.

a steam dryer being loaded onto a barge

For this test seal, we decided to use chevron V-packing in lieu of the traditional square packing. Whereas square-packing is made from woven PTFE and integrated graphite, the chevron V-packing is made of extruded polymer – which is optimally suited for maximal segregation of external oxygen from entering the internal dryer’s closed inert atmosphere. The V-packing is housed within a machined, cooling-jacketed, stuffing box.

an industrial dryer being transported down the river on a barge

To simulate a real processing environment, we mounted the test unit on a slew bearing, and allowed to float with the rotating seal surface using adjustable die springs.

an industrial dryer being transported down the river on a barge

Electrodes were attached to induce heat and ports were used to pressurize the system up to 1 PSIG, and gauges were installed and monitored.

a steam dryer in transport along a railway

The test unit operated continuously over the course of three years with only minimal tweaking such as bearing lubrication. The test data confirmed the effectiveness of using the longer life chevron V-packing on both the feed and discharge end of central discharge dryers in petrochemical applications. They significantly limit the leakage of ambient atmosphere or vapors and prevent the intake of external oxygen.

Why Central Discharge?

The Louisville Dryer “CS” Central Discharge Steam Tube Dryer design was developed for solvent extraction, and processing materials wetted with liquids other than water, which must be processed in an inert atmosphere and where the vapors must be captured and not allowed to escape to atmosphere.

replacement dryer being installed by louisville dryer company crew

Many materials at some point in their manufacture are volatile and reactive with O2 which can degrade the product, ignite, or explode. Some materials are processed with acids or volatile liquids where if leaked to atmosphere can cause injury to personnel, or damage to surrounding equipment or facilities.

The Louisville Dryer “CS” Central Discharge Steam Tube Dryer reduces the required sealing area by conveying the dried product through the center of the steam chest with helical discharge flights, into a very efficiently sealed discharge housing. The “CS” sealing mechanism is comprised of a machined mechanical seal and packing assembly which allows for static and dynamic purging with a variety of process gases and/or steam. Cooling water can be used in applications where required, as well as grease purge glands.

replacement dryer being installed by louisville dryer company crew

The Louisville Dryer “CS” seal design can be designed for process side pressures up to 1.5 PSIG, and in a number of carbon steel alloys and nickel alloys for highly corrosive applications. They are most effective when installed on both the feed end of the dryer and the discharge end.

Test Your Product in Louisville Dryer Company’s Test Lab

Curious how testing your product in our production-worthy scaled dryers in our own leading-edge research and development lab can benefit your company? We have manufactured coolers to help companies develop new products such as wood composite, airbag propellant, rocket fuel, algae-derived oils and others. Our test engineers can help determine best processes and equipment for your team. Call us today at 800-735-3163.

Reducing Costs and Harmful Emissions with Green Drying

Reducing Costs and Harmful Emissions with Green Drying

Some rotary dryer manufacturers specialize in green drying by incorporating low energy and ecological features into their designs. Such eco-friendly measures can significantly reduce the operating expenses of processing industry businesses. Using clean steam rather than products of combustion, steam tube dryers are one of the most ecological drying technologies.

Steam tube dryers are indirect-heat dryers utilizing the latent heat from clean low-temperature saturated steam rather than hot gases used in fossil fuel-fired combustion systems. This highly efficient heat-transfer design also makes steam tube dryers one of the most thermally efficient drying technologies.

a steam dryer being loaded onto a barge

Pictured Above – Another clean green drying machine, we custom-engineered and built this massive steam tube dryer for processing mass quantities of canola flakes for an oil seeds processor in central Canada.

Higher thermal efficiency means lower fuel consumption and lower operating costs

Many industrial processes now utilize waste heat boilers which are designed to use process waste streams, or biomass, as fuel. What was once a waste stream can now be a low cost environmentally-friendly energy source in a steam tube dryer, which are often used to replace less efficient, higher emission drying processes.

Some steam tube dryer designs use low temperatures which release fewer volatiles from organic compounds than other types of higher temperature, direct heat drying technologies. This eliminates the need for costly thermal oxidizers often required for other drying technologies.

Lower temperature operation also means lower thermal stresses on the equipment and longer intervals between major maintenance requirements. As a premier rotary dryer manufacturer of long-lasting steam tube dryers, some of our steam tube dryers in service today were commissioned over 75 years ago.

an industrial dryer being transported down the river on a barge

Pictured Above – Weighing 610,000 pounds (empty shell weight) and 12’-9” in diameter and 128’ long, our steam tube dryer journeyed to Canada via highways, railways and waterways (as shown here rollin’ on the river).

Louisville Dryer’s steam tube dryers do not use heated air as energy to drive the drying process. Only a very small volume of air is used to carry out the water vapor generated in the drying process of their units. With such a small exhaust volume discharged from their dryers, the size and horsepower requirements of the air handling equipment are normally 80% less than direct-heat dryers. And, in some processes, the small amount of exhaust gas is sent directly to the boiler as combustion air, completely eliminating air emissions.

Turn Waste into Profit

The larger volumes of dryer discharge gas from Louisville Dryer steam tube dryers are used in many industries to convert process waste streams into valuable secondary products.

a steam dryer in transport along a railway

Pictured Above – Our jumbo steam tube dryer custom built for a Canada-based oils seeds processor made part of its journey north via 18-axle trailer and railway.

Some examples include:

The residual spent grains from the fermentation process in both beverage alcohol and ethanol production are dried in steam tube dryers and sold as high nutrient animal feed.

In the manufacture of soda ash, steam tube dryers are used to convert sodium bicarbonate into sodium carbonate – where CO2 is generated, captured in the dryer, and returned to the process to make more feedstock. Direct heat drying technologies would contaminate the valuable CO2 by-product.

Waste paper sludge which for decades had been sent to landfill is now being dried in Louisville Dryer’s steam tube dryers and returned to the boiler as fuel.

View our extensive list of customer products which our steam tube dryers and our other types of drying systems have heated, dried and processed over the years.

replacement dryer being installed by louisville dryer company crew

Pictured Above – Louisville Dryer Company steam tube dryers are frequently selected by distilleries and other grain processors across the country.


To learn how your company can benefit from the green technologies of a steam tube dryer, watch our video series here and call our applications engineers today at 800-735-3163.

Five Important Questions From the Petrochemical Industry

Five Important Questions From the Petrochemical Industry

When it comes to rotary drying equipment in the petrochemical industry, versatility is key. Such a substantial investment requires research and careful consideration. It’s essential to weigh the pros and cons, as well as heed advice from experts on the subject. 

Louisville Dryers have been a production asset for the petrochemical industry for over 130 years. As the industry has changed and evolved over that time, Louisville Dryers have changed right along with it. Always improving aspects of our design and equipment, we focus on meeting the ever-changing needs of petrochemical production.

Industries considering the investment and commitment of a petrochemical product dryer can glean wisdom and knowledge from our Senior Applications Engineer, John Robertson. John has worked in the industry for over 35 years and is an outstanding asset to the Louisville Dryer team and our customers. 

Recently we asked John to answer five top questions customers often have about our company and petrochemicals. John offers the answers to these questions with simplicity and expertise.


The Petrochemical Industry’s Five Questions 

As answered by Senior Applications Engineer, John Robertson

What role does Louisville Dryer play in the production of petrochemicals?

Louisville Dryers have been synonymous with rotary drying equipment for over a century. We do everything from the designing, manufacturing, and installation of a variety of rotary process equipment for the petrochemical industry. 

Our expansive areas of expertise include: 

Each piece of equipment is specifically and uniquely designed to accommodate the mechanics and the processes of the product application.

What makes our Steam Tube Dryer, in particular, well-equipped for the petrochemical industry?

When it comes to longevity and saving money over the life of the equipment, it all comes back to precision and efficiency. 

Our Steam Tube Dryer is the most efficient type of rotary dryer because of its steam-filled tube heating source. The steam is only replaced when heat is transferred to the product itself, so the amount of heat loss from the system is very minimal. Our Steam Tube Dryer allows for slow gentle drying, so the moisture that’s physically held within the particles of the product can move to the surface and dry. 

The sheer versatility of our Steam Tube Dryer makes it a home run for the vast operations of the petrochemical industry. It can be used in many different applications and can be modified to suit specific plant or product needs. 


What unique capabilities make Louisville Dryer a good fit for working within the petrochemical industry?

Louisville Dryer designs and manufactures all of its equipment in various alloys to suit the nature and product of the plant. Standard stainless steel, 304 and 316, duplex stainless steel, super stainless steel, as well as corrosion and heat resistant nickel alloys can be incorporated into our equipment. 

If a product needs an inert atmosphere or if a solvent is being driven off and needs to be recovered, we can design special seals for the feed and discharge hoods that limit the leakage of the ambient atmosphere or the loss of solvent. 

We can also design the dryer to use a steam pressure of up to 450 PSIG if a chemical reaction needs to take place. Our Steam Tube Dryer can also purely be used as a heat source to bring a product from one temperature to another.


How can companies in the petrochemical industry save money by going with Louisville Dryer?

Our exceptional quality. 

Louisville Dryer’s commitment to quality control is the number one factor that saves companies money over going with another brand of dryers. 

Our clients demand reliability, and we give it to them. All of our equipment is designed and manufactured with extreme precision and robust components. Our goal is to run continuous operations that meet or exceed our clients’ production needs. We are focused on less maintenance, less loss of production, and less equipment replacement. 

But don’t just take our word for it. Look at our proven record. Louisville Dryer has equipment in the field that has been in operation for 50 years, and we will continue to uphold our reputation of reliability for years to come. 


How can someone get the best insights and information about their specific petrochemical needs?


Contact us. The Louisville Dryer team is open and willing to share our knowledge with you. This is a substantial investment, so we want to feel confident about your decision and make sure you get it right. 

Our employees have hundreds of years of combined experience in mechanical design, process design, manufacturing, application, and service of industrial rotary processing equipment, especially dryers. You can speak with us directly and even schedule a site visit. It starts with making a phone call to us at (800) 735-3163 or by taking a moment to fill out our online contact form.


See Our Petrochemical Case Study: