When you would need a Steam Tube Dryer vs. a Direct Heat Dryer

When you would need a Steam Tube Dryer vs. a Direct Heat Dryer

Choosing the right drying system is a significant investment and critical to your process. It is essential to know the variations between the different dryer options. The heat source is one of the most common differences. Read on and consider the following reasons why we often recommend a steam tube dryer over a direct heat dryer.

 

Steam Tube Drying vs. Direct Heat Drying: What’s the Difference? 

 

Steam Tube Drying  

Steam tube dryers perform as if it were a rotating tube with a shell heat exchanger. The drum is fitted with a high-pressure chamber that distributes steam into tubes running the length of the drum. Because its applications are for low-temperature processes, the equipment required for thermal destruction is reduced or eliminated. 

 

Steam Tube Dryers Are the Most Efficient Industrial Dryer

The most efficient of all the dryers, the steam tube dryer has very little air being exhausted – making the stack loss significantly reduced. The air pollution control system is also much smaller in a steam tube dyer and, since only a minor amount of air is used to sweep out the water vapors, the exhaust volume is a fraction compared to that of a direct heat dryer.

Steam Tube Dryers are also one of the easiest dryer types to operate. Once the steam pressure is set, the unit will take what it needs to do the job. Think of it as having a set-it-and-forget-it technology.

A steam tube dryer is used extensively in processing high-moisture organic materials such as distiller’s grain, gluten feed from the wet milling industry, oilseeds, and a variety of sludges.

steam tube dryer

 

How Does an Industrial Steam Tube Dryer Work?

Material is fed into the drum and tumbles over the outside of the inner tubes. Inside those tubes, steam is collapsing to condensate. The latent heat from the steam—about 850 BTUs per pound—provides the heat energy for drying. The condensate from the steam is removed through a rotary joint. It is then taken back to the boiler for regeneration.

 

Direct Heat Drying

 

How Does A Direct Heat Rotary Dryer Work?

A direct heat rotary dryer uses a hot gas which is induced into a rotary drum. Its heat source may be as simple as a steam coil in low-temperature applications, or it can have a burner for higher temperatures. The burner may combust into a chamber or it may fire directly into the dryer drum. We use the term direct-fired when there is no combustion chamber.

direct heat dryer

 

Direct heat dryers typically work best when the burner system can operate with a minimal amount of excess air or near stoichiometric balance of the gas and air. This allows the dryer to minimize the air required to carry the thermal energy.

 

 

frac sand dryer

 

Wet material is fed into the same end of the drum (parallel flow) or the opposite end of the drum (counterflow) and is picked up and showered (or veiled) into the hot gas stream. The thermal energy is transferred from the hot gas to the material, which heats the solids and the water, ultimately evaporating the water. The primary heat transfer is by convection.

 

frac sand dryer

If your product is not affected by heat from the burner flame or the products of combustion, then a direct-fired unit will provide an efficient drying solution through the full utilization of all three heat transfer methods: radiation, convection, and conduction.

Heat-sensitive materials such as biomass and organic products could be processed with either a direct heat dryer (with an air heater to control the temperature) or a steam tube dryer.

 

 

Why Choose a Steam Tube Dryer over a Direct Heat Dryer? 

 

Developed more than 100 years ago, the Louisville Steam Tube Dryer has always been a quality choice for drying high moisture organic by-products such as brewers’ and distillers’ spent grain. Today, this same dryer technology serves thousands of applications. 

 

What Materials Does an Industrial Steam Tube Dryer Process?

A steam tube drying system is our recommended choice for drying and processing inorganic and organic chemicals and other bulk solid materials including, but not limited to: 

  • Hemp
  • Dried distillers grains (DDG, DDGS)
  • Wet corn (fiber, grits, meal)
  • Wood chips
  • Soda ash
  • Paper mill sludge
  • Oil Seed (soy, sunflower, canola)
  • Soy meal
  • Chemical products
  • Petrochemical products (TA, PTA)
  • Lithium processing
  • Copper concentrate

All our dryers, including the steam tube system, are built in our state-of-the-art factory using proven technologies. Our in-house design team of engineers have vast experience in every type of process and industry; thus, our customers always receive a drying system that is custom fit for their operation. 

 

5 Benefits of A Steam Tube Drying System  

 

#1: More Cost-Effective

Louisville Steam Tube Dryers have been proven superior to other types of indirect-heat dryer installations in which hot gas, rather than steam, is used as the heat source. We provide solutions with the Lowest Cost per Revolution throughout our industries. Maintenance savings alone have often prompted the replacement of other dryer systems with the steam tube dryer.

 

 

#2: Better Quality

A steam tube dryer is classified as an ASME vessel. Thus, the requirements for its construction are more stringent than for other dryers. 

 

 

 

#3: More Efficient 

The steam tube dryer generally operates at a lower temperature than other dryers and rotates at a slower speed. Material tumbles gently around tubes that rotate with the shell, eliminating the friction forces that other types of dryers require.

 

 

 

#4: Easier Maintenance

Louisville Steam Tube Dryers enjoy a longer lifespan than most other dryers and require very little maintenance.

 

#5: Environmentally Friendly

Steam Tube Dryers are environmentally friendly. Since the steam tube dryer utilizes the latent heat of steam to drive the drying process, only a small amount of sweep air is required to remove the water vapor driven off the product generated in the drying process. Typically, the method uses less than about 30% of the exhaust gas required for a direct heat dryer

 

Purchasing A Steam Tube Dryer 

 

Because choosing the right drying system is a major investment and critical to your process, you should be sure you are getting the best equipment available. The Louisville Dryer Company manufacturing facilities hold esteemed accreditation by the American Society of Mechanical Engineers (ASME) and The National Board of Boiler and Pressure Vessel Inspectors

We extend personal attention and service to each customer, ensuring that their rotary processing equipment needs are efficiently met. If you are interested in learning more about the Louisville Dryer Company Steam Tube Drying System and its applications, please reach out directly to Hank Lawson, our Senior Process Engineer. He would be happy to listen and discuss the best options available for your application.

 

Call (800) 735-3163 or fill out our online contact form to get started.

 

Can a Rotary Dryer Operate Under Positive Pressure?

Can a Rotary Dryer Operate Under Positive Pressure?

Our process engineers were recently asked if a rotary dryer could operate under positive pressure. We thought it would be helpful to share the answer and provide a concise review of the distinct roles of positive and negative pressure within a Rotary Dryer system.

Atmospheric pressure is the downward force from the weight of air

Air Pressure, How Does It Work?

First, let’s consider a non-industrial description of air pressure. In the context of barometric pressure as reported by a weather forecaster, we essentially live at the bottom of a sea of air. That air is pushing down on our bodies at a force of about 14.7 pounds per square inch (atmospheric pressure at sea level).

In a closed system such as one with an attached pressure gauge that is set to zero, when suction is applied to the attached line in that system, air would be withdrawn from the system, and the gauge would then read less than zero.  Pressure that is lower than barometric pressure is negative pressure. Whereas if air was blown into the system, the gauge would read positive.

There are positive and negative air pressures

Similarly, in terms of pressure within a building, when you have a fan blowing air out of your house, you can open a window and then fresh air will enter the house – because the pressure in your house would be negative (lower than atmospheric pressure).

If you were to turn that same fan around – and blow air into your house, then the air already in the house would exhaust through the open window because the building is being positively pressurized.

 

How Air Pressure Effects the Drying Process

As it applies to a rotary drying vessel, a positive pressure is created at the burner from the combustion blower system while the rotary dryer is kept at a slight negative pressure to maintain burner flame envelope and to facilitate evacuation of evaporated moisture and dust particles in a controlled manner.

Dryer Pressures effect burner flame shape and efficiency

That negative pressure is controlled by the induced draft fan which can be adjusted to increase the air velocity through the dryer to allow more of the material dust particles to be directed out of the product stream to the Dust Collection system which reduces fines in the finished product. Conversely, the air velocity through the dryer can be reduced to allow more of the finer particles to drop out of the air stream prior to leaving the dryer.

A Switchgrass Dryer and Dust Collection System by Louisville Dryer Company

With each of those factors in mind, the system’s fan should be properly configured so that the dryer is always operating under a slight negative pressure. Under this condition, combustion gases and noxious vapors can be directed to the air pollution control system and not escape through the seams.

A thorough understanding of how pressure dynamics relate to heat management, moisture control and dust flow is integral to the proper design and efficient operation of industrial drying equipment. So, rotary dryer owners and operators should wonder – and confirm – how well their dryers operate under pressure.

A three-stage classification system by Louisville Dryer Company. The knockout boxes and baghouse integrated with the rotary dryer effectively evacuate dust, fines and moisture from the drying process.

Louisville Dryer Company engineers have extensive knowledge and proven experience providing air/exhaust-handling solutions and complete dryer systems for customers throughout the U.S. and the world – from material assessment/product testing to the custom design, fabrication, installation, commissioning and servicing of all components – all of which helps you accomplish your business goals and our professional commitment to your Lowest Cost per Revolution.

To Learn More

Learn about our high-pressure steam tube dryers and other steam tube dryers, and then to request help designing your industrial drying solution, contact our team today.

Why Processors Value Our Hemp Dryers

Why Processors Value Our Hemp Dryers

With the increase of popularity and mainstream approval of CBD oils and other hemp products, the hemp growing and drying industry is booming. As we continue to understand the uniqueness of hemp, more market opportunities are arising. It’s no wonder hemp processors are developing ways to have more control over the quality of incoming product.

Hemp farmers are experts in growing and harvest, and while the whole process from seed to sale is precarious, the drying process is especially volatile. A lot of crop rots because, without the right equipment, farmers can’t keep up with the drying demand. In our last article we talked about the growing popularity of co-ops and drying facilities to help streamline the process and make it more affordable for the farmers; but, there is another rising trend.

Hemp Processors Are Offering Drying Services

Many hemp processing plants are starting to offer additional services to their farming customers. By adding drying services, for example, they keep their farmers focused on growing more acres of plants while assuring their processing plants produce the best quality products available on the market.

Improving on the hemp drying process means providing a higher quality product while decreasing product loss.

The Right Equipment to Speed Hemp Drying

Louisville Dryer Company is an industry leader in hemp drying solutions. Just like processors want farmers to be able to focus on farming, we want processors to do what they do best. We know that most farmers and processors are not experts in drying equipment, but we are. We support our customers long after they make a dryer purchase because it’s important to us that your equipment operates properly and safely.

10 Benefits Of Our Hemp Dryers

Our hemp clients have improved the efficiency and thoroughness of their drying process by incorporating one of our hemp dryers while also protecting their cannabinoids and profitability. Here are 10 benefits to Louisville Dryer Company’s robust hemp steam dryer system:

#1: Continuous Process

Traditional batch processing is labor-intensive and requires handling the material multiple times. Our hemp dryer continuously dries and discharges material for as long as desired. Materials can be stored for delayed extraction or made immediately ready for the next step in the process.

#2: Size

Natural hemp drying requires a large footprint but our steam tube hemp dryer can replace a plethora of drying barns with the relatively small footprint of the dryer system.

#3 Speed

The chemical process of the hemp plant starts as soon as it is harvested. Hemp needs to be stabilized quickly so it isn’t actively rotting. The plant loses potency and value when you lose speed. With our steam tube dryer, hemp can be dried within minutes instead of days. Residence or dwell-time for materials in the unit is typically less than one hour at our quoted throughputs.

#4: Temperature

By using steam as the heating medium, you can directly control the pressure and set a “do not exceed” temperature to ensure there is minimal to no product degradation.

#5: Consistency

Depending on where you live and how the weather changes, drying times and efficiencies are likely to change a lot. A machine built for hemp drying provides a consistency to your process that you can count on. Even with varying particle size and moisture content, a Louisville Dryer hemp dryer adjusts to deliver consistent uniform material.

#6: Scalability

Our dryer’s production is directly related to the surface area of the tubes and can be easily scaled to match the desired throughput.

#7: Ease of Operation

The Louisville Dryer steam tube dryer is the easiest dryer to operate in the industry.

#8: Efficiency & Processing Rates

Our steam tube dryer has significantly fewer energy losses than a hot gas-fired system. It only uses as much steam as is required to heat and dry the material. Thermal efficiency is 80% in the steam tube dryer compared to 50%-65% in convective systems.

#9: Green/Environmental

Our steam tube dryer has less exhaust than other dryers – which means fewer greenhouse gases are produced.

#10: Process Simplification

Partial decarboxylation of the hemp that takes place within the steam dryer leads to less processing needed downstream. Decarboxylation requires heat and time to unlock the therapeutic effects of cannabinoids. Hemp naturally contains CBD-A, which needs to be activated through decarboxylation to make CBD. It’s a very important process but timing is EVERYTHING. Our hemp dryer puts you in control of the decarboxylation process and prevents significant loss of your crop and profits.

Why Are Processors Choosing Louisville Hemp Dryers?

Processors are thinking ahead towards future growth and they want a machine that makes it possible to grow and process more plants at top quality. They cannot afford to risk ruined products because the hemp farming business demands are growing faster than the farmer’s processing capabilities. A hemp drying system by Louisville Dryer Company is a wise solution to helping processors (as well as farmers and drying facilities) to achieve a level of production needed for their business growth.

Processors need:

  • Dry, stabilized biomass
  • Moisture levels at 10% or less
  • Free of mold or mildew
  • No excess fiber which dilutes the CBD numbers
  • Finely shredded materials

Louisville Dryer Company’s hemp dryers are manufactured to be easy to use and act quickly and gently on hemp biomass.

Whether you are growing and processing for cannabinoids or using other parts of the plant for various hemp products, our hemp drying technology makes all the difference in the quality of your end-product. Louisville Dryer Company’s hemp dryers are the right choice to grow and scale your business.

Contact Our Hemp Expert

Hank Lawson, Senior Process Engineer at Louisville Dryer, made it his personal mission to learn the best way our company can support hemp farmers, processors, and co-op hosts. He gained his experience first-hand by operating a small hemp farm so he could understand our hemp customers and their unique struggles. We invite you to reach out directly to him for insights into the unique issues involved with growing and drying hemp.

If you’d like to contact Hank or any of our team members about an industrial dryer, please call us at (800) 735-3163 or fill out our online contact form. A more efficient and profitable drying method could change everything for your hemp business.

Hank Lawson, Senior Process Engineer at Louisville Dryer

Could Hemp Drying Co-ops Make Farming More Profitable?

Could Hemp Drying Co-ops Make Farming More Profitable?

Reducing moisture is an essential part of hemp processing. The traditional method of hang drying is a long and tedious process where the hemp is hung upside down and dried by hand. Growers must remove the stems and then cut the plants into small pieces to dry more thoroughly. It is a time-consuming process that leaves little room for error. 

Drying only batches at a time, traditional hang drying requires:
  • Around 5-10,000 square foot per acre
  • Many days to dry
  • Days of curing after the drying
  • 12-15 people to do it successfully
  • Numerous fans and dehumidifiers for more consistent drying.

It’s a fickle process, and a lot can go wrong. If the hemp is dried too slowly, the resulting product can be low-quality or ruined completely. Higher moisture takes more time and energy to dry, and a lot of crop rots because farmers can’t keep up with the drying demand and the army of people it takes to complete it. 

This method is not scalable or profitable, and most hemp farmers who try it will only ever do it once. 

As we heard someone recently say, “There aren’t enough arms and barns for where the hemp industry is going.”

Reliability and Profitability from Seed-to-Sale

Success in the hemp industry starts with the farmer. If the farmer can’t grow successfully, the whole industry is affected. 

While the former process of harvesting, drying, and storing was adequate for growing a couple of acres of crop, hemp growers who wanted to increase production needed to speed the processing rate of wet biomass. 

With the increase of popularity and mainstream approval, the hemp growing and drying industry is booming. Laws have shifted to allow growth, processing, and transportation of hemp—even across state lines. Improving the hemp drying process means farmers can provide a higher quality product and decrease their product loss.

The problem for many farmers is cost and sustainability. 

       We understand. 

Known for our robust dryer systems, Louisville Dryer understands that the hemp market is turbulent and requires affordable dryers. We have worked diligently to bring a dryer to the market which also meets the needs of hemp producers. 

Hemp farmers need practical solutions to enhance reliability and profitability from seed-to-sale.

Our equipment is tailored to the process and we examined the return on investment for the end-user. When we work with farmers, they need to know they can trust our reputation and experience because they are not experts in industrial dryers. Our service to our hemp clients doesn’t stop with the purchase. We provide customer support after the sale to make sure the equipment operates properly and safely.

A Unique Option: Hemp Co-Ops and Drying Facilities

If you’re a farmer that wants to grow in the hemp and CBD industry, you will need to produce a top-quality product. Yet, many hemp farmers are unsure if they need an industrial-sized hemp drying system. 

Hemp co-ops and drying facilities may be the way of the future. 

Hemp co-ops and drying facilities team people together to share industrial machines—like our hemp dryers. They pool their money to purchase manufacturing equipment and then allow farmers to become members to gain access to their resources.

These co-ops and drying facilities provide a cost-effective opportunity for farmers and allow local-areas access to drying services. They maximize profit, reduce the cost of doing business, and mitigate risks. Also, members help other members through education, knowledge, expertise, experience, influence, capital, relationships, and other resources. Their commitment is to serve the farmer, from the field to the final product.

Don’t have a hemp drying co-op near you? This may be an opportunity to join with other growers in your area and get one started.

The Highest Standard of Hemp Production

Louisville Dryer has a desire to partner with the agriculture industry, drying co-ops, and drying and bagging facilities to create the highest standard in hemp production. We can help you speed up the long and tedious process of drying hemp for more efficient and consistent results.  

There are three things you should consider before investing in a hemp dryer:

  1. How much material do you want to dry?
  2. Calculate the dryer production rate in pounds per hour. 

Divide the pounds you plan to produce by the daytime hours you have to harvest. 

  1. Submit your Request for Quote for the dryer early. We suggest starting your purchase process in the winter

Allow five (5) to six (6) months to build and install the equipment. 

Our custom-designed hemp drying system is ideal for improving the process of hemp drying. Our equipment uses the proper time and temperature controls to remove the plant’s moisture without damaging its integrity. Our engineers also understand the importance of the decarboxylation process, which requires the proper heat and time to unlock the therapeutic effects of cannabinoids. 

 

Let’s Connect And Grow Together

Whether you already own a hemp co-op or drying house, or you are considering starting one, we’d love to talk to you about how our hemp dryers can be part of your scalable plan for growth. You’ll be making an investment that will create future growth for yourself and many other farmers and processors. Over time you’ll find that your expenses can be significantly minimized by automating your process, reducing risk, and cutting overhead costs.

Louisville Dryer is a leader in hemp drying solutions. Our hemp clients have been able to improve the efficiency and thoroughness of their drying process. We have the knowledge and experience to help businesses like yours increase profit and sustainability. We can help you meet the unique needs of your business to produce a final quality product.

We engineered our hemp dryers to be fast and gentle on hemp biomass. Whether you are growing for cannabinoids or using other parts of the plant, our drying technology makes all the difference in the quality of your product.

Think about your future. Not only can our hemp dryers help you now, but they can also help you grow into a larger operation. We’re here to grow and scale with you. 

 

Modernizing Hemp Drying for Efficiency and Profit

Modernizing Hemp Drying for Efficiency and Profit

For years, farmers hung hemp plants in environmentally controlled tobacco barns, where the harvest required a drying-time of three to five days. The barns needed to be retrofitted with forced-air units to dry the excess moisture out of the plants. Each farm required as many as 20 barns, each large enough to hold up to an acre’s worth of harvested plants. 

There has been a steep rise in the hemp growing industry since the 2018 Farm Bill legalized hemp-derived products. It’s no wonder many farmers started looking for ways to cash in on this rapidly growing market. Just three years ago, the U.S. hemp industry was producing around $820M in revenue, but experts expect that number to rise by approximately 15% by 2022.

A Better Way for Hemp Drying

When properly dried and processed, valuable CBD oil can be extracted from the hemp plant and used in a variety of in-demand products. While the former process of harvesting, drying and storing was adequate for growing a couple of acres of crop, hemp growers who wanted to increase their production quickly realized the need to speed the rate at which wet biomass is processed. 

Louisville Dryer did extensive research to develop a dryer that would alleviate the need for faster drying. We started with a desire to understand the unique position of hemp farmers. Hank Lawson, our Senior Process Engineer, made it his mission to learn how our company could best support hemp farmers and improve their business. 

“Properly drying your hemp is an essential part of processing it for CBD oil extraction or other medical or industrial purposes. I made it my mission to get you the best equipment to speed up your drying process, while also understanding all of your pain points as a grower.”

– Hank Lawson, Senior Process Engineer

Hank grew two-acres of hemp and saw the farming process through to drying and extraction. It provided invaluable insights into what hemp farmers experience as they plant, grow, harvest, dry, and extract. The most notable thing Hank learned was how much work it takes to grow hemp. After enduring the entire process, it was even more motivating to the Louisville Dryer team to develop the best agricultural-grade direct heat dryer available to our hemp farming clients. 

 

Farming, Drying, and Processing Hemp to Maximize your Harvest – Our Journey

 

Specific Needs for Drying Hemp 

Using Hank’s research, Louisville Dryer designed and manufactured our hemp drying system to improve your specific hemp-drying needs. Our design implements the same technology we have been using for decades to dry other agricultural products successfully but addresses two particular needs. 

Steam Tube Dryer

Steam Tube Dryer

#1: Moisture Levels Reduction

Hemp has a naturally high moisture level content, making it is critical to reducing its biomass to an acceptable level of moisture to extract quality CBD oil. 

#2: Decarboxylation Process 

If you wish to create CBD products from the cannabinoid-rich oil extracts derived from your hemp harvest, decarboxylation is essential. It is the necessary process of converting THCA or CBDA into the THC or CBD. 

Get The Outcome You Need

What if you could expedite decarboxylation through the drying process? You can.

Hemp dried in our Steam Tube Dryer aids in the decarboxylation process at the same time moisture is removed. This makes the extraction process move faster. 

We developed our steam dryer models to specifically dry 4, 6, 8 and up to 10 tons of wet hemp biomass per hour with an output moisture content between 10-12%. The result is a more efficient extraction with a higher yield. And a higher yield means higher profit per acre.

Louisville Dryer also builds direct heat dryers for customers who do not have steam.

Removing a Barrier to Higher Profit

While our hemp dryer shares many similarities to our other direct heat dryers, one distinguishing factor for this product is that it’s priced especially for the agricultural economy. It is more affordable than some of our other models of direct heat dryers.

If you’re looking for a more efficient drying system that includes decarboxylation, we can help streamline your process. 

We Are Here for You

Reach out directly to Hank for his specific insights into the unique issues involved with growing, harvesting, and drying hemp. He is always happy to have a conversation and is uniquely positioned to anticipate your needs.

If you’d like to contact Hank or any of our team members about a direct heat or steam tube dryer, please call us at (800) 735-3163 or fill out our online contact form. A more efficient and profitable drying method could change everything for your hemp business.