Rotary Dryer for sale

What are Rotary Dryers?

The single cylinder rotary dryer is for drying bulk materials in various industries: building materials, metallurgical, chemical, glass, etc. On the basis of heat engineering calculations, we select the most optimal dryer size and design for customer requirements.

The capacity of the drum dryer is from 0.5 tph to 100 tph. According to the calculations, a loading chamber, a burner, an unloading chamber, a mechanism for dust collecting and gas cleaning are manufactured. The dryer adopts automation system and a frequency drive to adjust the temperature and rotation speed. This makes it possible to vary the drying parameters and overall performance within a wide range.

Why Do We Need Rotary Dryers?

You need a rotary dryer for one primary reason: control. Raw materials from a quarry or stockpile have inconsistent moisture levels. This inconsistency is a disaster for any precise manufacturing process, like making concrete blocks. If your sand is too wet, your blocks will slump and have low strength. If it is too dry, it can absorb too much water from the mix, starving the cement of the water it needs for proper hydration. A drying system removes this variable. It gives you a perfectly consistent raw material, which directly leads to:

• Higher Product Quality: Fewer rejected blocks and more consistent strength.
• Reduced Costs: Less wasted cement, water, and labor from bad batches.
• Increased Production Speed: No need to constantly adjust your block machine mix formulas.
• Lower Transport Weight: Removing water from minerals or other products significantly reduces shipping costs.

Ultimately, a rotary dryer gives you control over your process, and control is the key to profit.

What are Different Types of Rotary Dryers?

Rotary dryers are mainly categorized by how they heat the material. The two most common types are direct heat and indirect heat dryers. Understanding the difference is crucial for choosing the right machine.

• Direct Heat Dryer: In a direct heat dryer, the hot gas from a burner comes into direct contact with the raw material. Think of it like a giant, industrial-scale clothes dryer. This is the most common and thermally efficient type of rotary dryer. It is perfect for robust materials like sand, clay, stone, and minerals that are not damaged by contact with the combustion gases. The vast majority of dryers used in the construction and mining industries are direct heat models because they offer the fastest and most economical drying.
• Indirect Heat Dryer: In an indirect heat dryer, the material does not touch the hot gas. The rotating drum is enclosed in an outer chamber or has internal tubes through which the heat is passed. The heat transfers through the drum’s metal shell to the material inside. This method applys for materials that are sensitive, combustible, or cannot be contaminated by exhaust gases, such as certain chemicals, foods, and specialty minerals. While less common, they are essential for specific high-value applications. The choice between direct vs indirect rotary dryer depends entirely on your material’s properties.

What are Applications of Rotary Dryer?

The what is a rotary dryer used for question has countless answers, as its applications span dozens of industries. At ZONEDING, we focus on heavy industrial applications where reliability is key. Some of the most common uses include:

• Construction Materials: Drying sand, gravel, and crushed stone for concrete and asphalt production. This is our primary focus.
• Mineral Processing: Drying concentrates like iron ore, copper, and limestone before further processing.
• Agriculture: Drying fertilizers, grains, and animal feeds for storage and sale.
• Waste Management: Drying municipal sludge, coal slurry, and other industrial byproducts.
• Chemical Industry: Drying various salts, powders, and crystals.

What is the Applicable Materials for the Rotary Dryer?

Rotary dryer is suitable to dry metallic and non-metallic mineral, clay in cement industry and coal in coal mine etc. For example, sand, vinasse, slag ,sludge, coal powder, sawdust, limestone powder, rice husk, mineral powder , clay, etc.

A rotary dryer is incredibly versatile. It can handle a huge range of materials, provided they are in a bulk or granular form. Here is a short list of common materials:

• Minerals and Ores: Sand, clay, limestone, quartz, slag, coal, fly ash, iron ore, copper concentrate.
• Fertilizers: Potash, phosphate, and other compound fertilizers.
• Building Materials: Sand, gravel, cement, gypsum.
• Biomass: Wood chips, sawdust, bagasse.
• Waste Products: Sewage sludge, animal manure, industrial residue.

Very sticky materials may require a back-mixing system to prevent them from clumping and sticking to the dryer shell.

Working Principle of Rotary Dryer

The working principle of a rotary dryer is based on gravity and heat exchange.

The wet materials that need to be dried are sent to the feeding hopper by a belt conveyor or a hoist, and then enter the material end through the feeding pipe. The slope of the feeding tube is greater than the natural inclination of the material, so that the material can enter the dryer smoothly.

The dryer cylinder is a rotating cylinder slightly inclined from the horizontal line. The material is added from the higher end, and the heating medium is in contact with the material. With the rotation of the cylinder, the material moves to the lower end under the action of gravity. In the process, the material and the heat carrier exchange heat directly or indirectly, so that the material is dried, and then sent out through a belt conveyor or a screw conveyor.

What are Features of Rotary Dryers from ZONEDING?

When you look at a rotary dryer, it might seem like a simple steel tube. However, the difference between a machine that lasts 5 years and one that lasts 30 years is in the engineering details. At ZONEDING, we build our dryers for long-term performance and reliability. A critical feature to examine is the trunnion rings (tires) and the girth gear. A cheap dryer might use a simple rolled steel bar for its tires, which wears unevenly and can’t be repaired. We use forged and machined trunnion rings. They are perfectly round, have hardened surfaces, and are designed to be resurfaced in-place after decades of service.

Similarly, the girth gear that turns the drum must be a two-piece or four-piece, cast steel, spring-mounted design. A one-piece gear welded to the shell cannot absorb the immense stress from thermal expansion and flexing. This stress will eventually crack the gear or the shell itself. Our spring-mounted design allows the gear to “float,” isolating it from these forces and ensuring a multi-decade lifespan. These are not just features; they are a philosophy of building equipment that becomes a long-term asset, not a short-term expense.

Zoneding Rotary Dryers Advantages

• Highly Customizable: Tailored to specific material requirements, with options for high/low inlet temperatures, short/long residence times, and co-current or counter-current flow modes.
• Wide Specification Range: Diameters from 3′ – 15′ (1 – 4.6m) and capacities from 1 TPH – 200+ TPH (1 MTPH – 181+ MTPH).
• Efficient Heat Transfer: Specially designed internal lifting flights maximize heat exchange efficiency between the material and the hot gas stream.
• Robust and Durable: Heavy-duty design and construction ensure long-term stable operation and extended service life.
• Flexible Configurations: Available in both co-current (parallel flow) and counter-current airflow configurations.
• Various Drive Assemblies: Different drive assemblies available to suit specific needs.
• Multiple Material Options: Choice of materials including Carbon Steel, Stainless Steel, Specialty Alloys, Explosion Bonded, and AR (Abrasion-Resistant) Steel.
• Broad Fuel Adaptability: Accommodates various fuel types such as Fuel Oil, Natural Gas/Propane, Waste Heat, and Biomass.
• Process & Mechanical Warranties: Comprehensive warranties covering both process performance and mechanical aspects.
• Added Benefit: For agglomerated materials, the tumbling action also provides rounding and polishing effects.

Rotary Dryers Burner

Gas burners, light oil burners, heavy oilburners, pulverized coal burners, andbiomass pellet burner, etc.

Burning chamber

Provide space for fuel combustion, theend of the chamber is provided with anair inlet and an air regulating valve, andthe interior is built with refractory
cement and bricks, and the temperaturein the burning chamber can reach up to1200 C. lts structure is exquisite andreasonable, and it is closely combinedwith the dryer cylinder to providesufficient heat source for the dryer

The Classification of Rotary Drum Dryer

Given different structures and applications, the rotary drum dryer is divided into several types. And thus, drying technology is more targeted.

According to the structure, rotary dryers are divided into the single-cylinder type and multi-cylinder type.

Based on experience and customer feedback, Zoneding engineers will recommend the single-cylinder rotary dryer. These two types of rotary dryers have almost the same drying efficiency. While the structure of the single-cylinder one is simpler, resulting in more convenient daily maintenance. The maintenance personnel can directly get into the cylinder body for inspection. For multi-cylinder dryers, this is difficult to achieve.

Working site of single-cylinder rotary dryer and multi-cylinder rotary dryer

According to the heat transfer mode, the rotary dryer is divided into the direct type and indirect type, or it can also be divided into a co-current rotary dryer and counter-current rotary dryer.

What is the Structure of Rotary Dryer?

The main structure of a rotary drum dryer consists of several key parts working together:

1. Drum or Shell: This is the main rotating cylinder, made from heavy-duty steel plate. It houses the lifters and is the heart of the machine.
2. Burner and Hot Gas Furnace: Provides the hot gas needed for drying.
3. Feed and Discharge Chutes: The stationary points where material enters and exits the rotating drum.
4. Tires and Trunnion Rollers: The drum rides on massive steel rings called tires, which are supported by trunnion rollers. These carry the entire weight of the dryer.
5. Thrust Rollers: A set of smaller, powerful rollers that prevent the tilted drum from sliding downhill.
6. Drive System: A motor, gearbox, and large girth gear that rotates the entire drum assembly.
7. Sealing System: The seal is not an accessory; it is a key performance component. The points where the stationary chutes meet the rotating drum are critical. A poor seal allows cold “tramp air” to be sucked into the dryer, which kills your fuel efficiency. It also allows valuable product dust to escape. We use high-quality sealing systems, often with graphite blocks or spring-loaded leaves, to create a tight seal while allowing for thermal expansion. A good seal can improve fuel efficiency by 10-15% on its own and dramatically reduce dust in your plant.

How Does the Rotary Dryer Work?

The rotary dryer working principle is a combination of mechanics and thermodynamics. Material is fed into the high end of the tilted, rotating drum. Inside the drum are a series of metal plates called “lifters.” As the drum rotates, these lifters pick up the material and drop it from the top of the drum down to the bottom. This process is repeated over and over as the material slowly moves down the length of the dryer. The most important part of this process is the creation of a “curtain.”

Efficiency is not about maximum temperature; it is about the curtain. The most efficient heat transfer happens when the lifters distribute the material in a uniform, dense curtain that fills the entire cross-section of the drum. Hot gas from the burner is forced to pass through this curtain, giving up its heat directly to the material. If your lifters are poorly designed or the rotation speed is wrong, you get a poor curtain with big gaps. The hot gas then bypasses the material and goes straight out the smokestack. You could have a 1000°C inlet temperature, but if the gas is not touching the product, you are just heating the sky. A lower temperature with a perfect, dense curtain is vastly more fuel-efficient and is the secret to an effective drying system.

What is the Price of the Rotary Dryer?

The industrial rotary dryer price can range from $30,000 for a small, simple unit to over $500,000 for a large, high-capacity system. The price depends on one crucial factor: evaporation capacity, not tonnage. This is the single most expensive mistake customers make. They say, “I need a dryer for 20 tons per hour of sand,” and they get a price. But drying 20 tons of sand with 5% starting moisture is completely different from drying 20 tons with 20% starting moisture.

The second scenario requires a machine with four times the evaporation capacity. This means a much larger burner, a larger drum diameter for a longer residence time, and a more powerful fan system. Buying a dryer based on output tonnage without specifying the exact water removal rate is a recipe for failure. You will either buy a machine that is too small and can never meet your goals or one that is oversized and incredibly inefficient. A true price can only be determined after a detailed analysis of your material, moisture content, and production needs.

Rotary Dryer Specification

Drying Machine Production Process

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