February 1, 2008

8 Min Read
Drying & Evaporation Focus - February 08

Vacuum Dryer
This vacuum dryer can dry most solid materials to less than 0.5% moisture. The drying process is based on plow mixing technology, providing a mechanically fluidized bed of material to maximize product contact with the reactor vessel. The dryer can be operated at atmosphere to dry shear-sensitive materials that are not limited by temperature. If the material requires a short cycle time or if it is temperature sensitive, vacuum technology is implemented. High-speed choppers are available for deagglomerating lumps, ensuring maximum exposure of the material’s surface area to the process.
Scott Equipment Co., New Prague, MN 952-758-0440 www.scottequipment.com

Drying and Thermal Processing Systems
This company offers rotary dryers, coolers, kilns, calciners, and combination dryer-coolers. All designs are developed with efficiency, durability, and process flexibility in mind. Thermal systems can be designed in virtually any configuration. Examples are parallel flow or countercurrent flow models. Other examples are directly or indirectly fired models that utilize a variety of fuel sources such as natural gas, oil, steam, waste heat, etc. Single stand-alone thermal processing units or complete systems can be supplied.
FEECO International Inc., Green Bay, WI 920-406-6180 www.feeco.com

Thin-Layer Dryer
The Ecoflash thin-layer dryer allows for indirect heat drying using a thermal transfer fluid (hot oil) or saturated steam. Inside the drying chamber, a rotor equipped with adjustable pitch blades moves the material being dried in a dynamic action, creating an energy-efficient evaporation process. The evaporated water is removed from the dryer by means of a controlled countercurrent of air. The drying process is a one-pass continuous operation that results in a thermal load of less than 1450 Btu per pound of water.
Siemens Water Technologies, Holland, MI 229-227-8727 www.siemens.com

High-Temperature Walk-In Oven
No. 902 unit is an electric high-temperature walk-in oven with a maximum operating temperature of 850°F. Specially modified with rollout shelving, it is being used to heat-treat components at a customer’s facility. A 10,000-cfm, 7½-hp recirculating blower provides combination airflow to the workload, while 100-kW tubular heating elements are sheathed in Incoloy. This oven has overall workspace dimensions measuring 72 × 78 × 78 in., with a top-mounted heating chamber, aluminized steel interior and exterior, and three rollout steel shelves, each measuring 60 × 72 in. and rated for 400-lb loads. Oven walls measuring 8-in. thick have 2 in. of 1900°F block and 6 in. of rockwool insulation with a density of 10 lb/cu ft. The unit has inner and outer door gaskets.
The Grieve Corp., Round Lake, IL 847-546-8225 www.grievecorp.com

Cylindrical Plow Blender Dryers and Vacuum Dryers
These dryers use a combination of enhanced mixing technologies to fluidize ingredients. Fluidizing ingredients exposes more particles to the drying effects of heat and vacuum—that is, to indirect heating via ASME jackets designed for hot water, steam, hot oil, or vapor and to vacuum in a vacuum dryer. As a result, the flash point of liquid water or a solvent is lowered, shortening drying times and allowing for the lower-temperature drying and processing that are important for heat-sensitive ingredients. Enhanced mixing is achieved using agitators with a defined geometry at high rotational speeds, fluidizing ingredients and enabling particles of vastly different sizes, shapes, and densities to be mixed precisely and efficiently. Vessels can withstand internal working temperatures to 700°F, internal pressures to 700 psi, and full vacuum.
American Process Systems, div. Eirich Machines, Gurnee, IL 847-336-2444 www.apsmixers.com

Split-Shaft Seals for Dryers
Patented EX-PAC seals perform well on dryers, agitators, reactors, and other rotating equipment where thermal shaft growth, axial shaft movements, or pressure-vacuum cycles defeat other seals. The seals are available split and are offered in a variety of materials, making them compatible with hostile chemical environments and processes under 260°C.
Woodex Bearing Company, Inc., Georgetown ME 800-526-8800 www.mecoseal.com

Vacuum Dryer
VT vacuum dryers are based on state-of-the-art mechanically fluidized bed mix action augmented by high-speed choppers, the combined effect of which leads to efficient thermal processing technology. This unit can take products from liquids to dry powders. Because of the dryer’s excellent heat transfer and vacuum capabilities, products can be dried at lower temperatures than with comparable systems, making it ideal for temperature-sensitive materials.
Littleford Day Inc., Florence KY 800-365-8555 www.littleford.com

Single- and Twin-Rotor Dryers
TorusDisc indirect dryers can achieve heat transmission coefficients greater than many other indirect dryers. A design feature that is key to enhanced performance is the high relative velocity between the rotating disks and the product. Another is the dryers’ ability to set rotor speed for optimum heat exchange and thorough mixing independent of residence times. The units are indirect heat exchangers that mechanically agitate the material. They can be used for batch or continuous indirect heating, drying, cooling, or reaction of solids, slurries, gels, filter cakes, powders, and viscous materials. The rotors, disks, and body jacket can be heated or cooled with steam or thermal fluids. Agitator plows or scraper bars can be added to increase the exposure of new surfaces and prevent material buildup.
Bepex International, Minneapolis, MN 612-331-4370 www.bepex.com

Rotary Vacuum Dryers
These rotary vacuum dryers are designed and manufactured to suit the specific drying needs of difficult or sticky materials that can withstand agitation. During operation, materials are dried and mixed by a heated spiral ribbon or paddle agitator. Materials dry quickly and evenly without the problems associated with high-temperature drying. The systems are ideal for materials that are heat sensitive, pyrophoric, or subject to oxidation. The dryers are equipped with a vacuum gauge, vacuum-release valve, jacket pressure gauge, and jacket relief valve. They are fully enclosed, preventing product contamination and the release of hazardous gas into the air. The dryers are skid-mounted, piped, and wired, and they are tested for vacuum leaks.
McGill AirPressure LLC, Columbus, OH 614-829-1200 www.mcgillairpressure.com

Drying and Recovery System
Thin-film dryers are widely used throughout the process industries to convert liquids, slurries, and pastes to free-flowing solids in continuous, single-pass operation. Compact vertical and horizontal thin-film dryers can be operated individually or together as the Combi Dryer. Because of their low hold-up and self-cleaning heating surfaces, these dryers have a short residence time and are effective at processing heat-sensitive products. The systems are compact because they offer high heat-transfer rates. They are ideal for catalyst recovery, salt drying, and glycerin recovery.
LCI Corp., Charlotte, NC 704-394-8341 www.lcicorp.com

Dryers and Coolers
Bella dryers and coolers offer a new method of drying or cooling powders, granulates, and filter cakes. The dryers can be used for drying, mixing, spraying, agglomerating, and cooling in the same unit without the need for additional equipment or costs. Operation is extremely efficient because air flows around material while it is suspended in the weightless zone of the mixer. This maximizes the total surface that is exposed to the air, increasing the desired effect. The drying process undergoes adiabatic evaporation with thermal efficiency at about 80%. The units require lower air volumes than other fluidizing dryers.
Dynamic Air Inc., St. Paul, MN 651-484-2900 www.dynamicair.com

Fluid-Bed Batch Dryer
This circular vibratory fluid-bed processing system dries small batches of bulk solid materials. The self-contained system integrates an 18-in.-diam fluid-bed processor with a heater, blower, cyclone separator, and controls. The unit is ready for connection to a material inlet/outlet and power source. Intended for small-volume production and laboratory or pilot-plant testing, the system dries batches up to 1 cu ft. At the end of each drying cycle, a valve at the spout of the fluid-bed chamber opens automatically to evacuate the batch. Models up to 84-in. in diameter are available for drying, cooling, or moisturizing.
Kason Corp., Millburn, NJ 973-467-8140 www.kason.com

Vibrating Fluid-Bed Processors
These vibrating fluid-bed processors are custom engineered to match specific processing needs. They increase throughput while enhancing product quality. Capable of continuous or batch processing, the systems can be designed to heat, cool, coat, and dry product. They are available as individual units or complete system solutions.
General Kinematics Corp., Crystal Lake, IL 815-455-3222 www.generalkinematics.com

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