Airstream Drying

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Airstream Drying, Cooling and Calcining

Welcome to Barr-RosinAs a leading supplier of Airstream drying systems, we offer a choice of dryers to dry a full range of wet materials, fromgranules, cakes and powders to sludges, slurries andsolutions. The dry products can be in the form of powders,granules or pellets. Coolers and calciners can also beincorporated.

Combining over one hundred years of drying experience, wecan offer you a complete service with proven systems andinnovative solutions in response to your drying needs.

For decades both Barr & Murphy and Rosin Engineering havespecialised in Thermal Process Systems for the Food, Chemicaland Polymer industries. Now united within the GEA group, ourcombined experience gained from building thousands ofinstallations is available to you in our advanced drying andprocessing systems.

Now you can call upon the leaders in airstream drying. We areready to answer your call.

GEA’s philosophy:Leading Technology - Individual Solutions

The Result:Taylored Systems - A Tradition of Innovation

Tailored SystemsAll Barr-Rosin systems are tailored to our customers’ needs.Each application is carefully considered and the best solutionis provided based on pilot plant test results where requiredand taking full account of product and site requirements.

Pilot Plant FacilitiesFully equipped test centres located in England and Canadaprovide services for carrying out pilot plant trials oncustomers’ products. Complementing these services, we havea number of standard mobile pilot plants available for on sitetesting at your company. Custom-built pilot plants can also bemanufactured to meet your special drying requirements.When your objectives are to improve quality, performance andproductivity our know-how, experience and technology canwork for you.

Quality StandardsOur equipment can be produced in accordance with ISO 9000standards and can be manufactured in all grades of stainlessand carbon steels, aluminium, and specialised materials. Wemanufacture to DIN, VDI, ASME and National Standards asmay be required.

‘P’ type ring dryer for modified starch

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Drying is a natural process that can be found in almostevery sphere of our physicalworld. The largest dryer wehave is the sun.

At Barr-Rosin we design andbuild systems where heat andair flow are combined in waysthat allow efficient drying on alarge scale. Our designs haveevolved in response to industry’sneed for increased capacity andhigher product quality, all withimproved efficiency andresponsibility towards ourenvironment.

We are focused on building anddeveloping Airstream DryingSystems. These can be classifiedby the following types andgeneral characteristics:

FlashMoist particles are dried and conveyed in a stream of hot air- removes surface moisture- product dries in seconds- dryer with a small footprint

RingProduct conveyed in a hot air stream with classifier in circuit to select and recycle semi-dry solids- removes surface moisture and some internal moisture- provides rapid, even and gentle drying- system handles difficult materials

Fluidised bedMoist particles ‘float’ on a cushion of hot air through abubbling bed of solids- removes surface and bound moisture- ensures controlled drying rates- extended residence time with gentle processing- drying, cooling or calcining

RotarySolids are dried in a rotating drum and cascade through a hot air stream- handles a wide size range of materials with extended

residence times- design permits highest possible drying temperatures- drying, cooling or calcining

RosinaireSolids spiral through a jacketed cylinder by the action ofpaddles on a rotating shaft- safely processes hazardous substances and/or non-aqueous

solvents- gas tight nitrogen capability

ColumnBulk solids flow by gravity in counter flow to purge gas(where required)- ensures uniform flow with residence times measured in hours- low operating costsColumn Dryer- removes residual moisture / volatilesColumn Cooler- air free cooling of granular materials

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DryersThe pneumatic or ‘flash’ dryer is used with products that dryrapidly owing to the easy removal of free moisture or whereany required diffusion to the surface occurs readily. Dryingtakes place in a matter of seconds. Wet material is mixed witha stream of heated air (or other gas) which conveys it througha drying duct where high heat and mass transfer rates rapidlydry the product.

Many of the largest dryers in the world are flash dryers - someexceeding 20 tonnes of water evaporation per hour in a singlesystem. Inlet air temperatures range from 100ºC to 650ºC whileairflow can exceed 200,000 m3/hr.

Elevated drying temperatures can be used with manyproducts since flashing-off of surface moisture instantly coolsthe drying gas without appreciably increasing the producttemperature.

Applications include the drying of filter cakes, crystals,granules, pastes, sludges and slurries; in fact almost anymaterial where a powdered product is required. Proper feedconditioning is the key to drying materials with high initialmoisture contents, and these systems include:

• Single and twin shaft paddle mixers

• Cascading screens

• Disintegrators

• Kicker mills

• Rotary slings

As the drying air also conveys the product, this system can beused to discharge at elevation. Product is separated from thedrying gas in either single or multi cyclones, and/or bagfilters. Sometimes cyclones are followed by scrubbers for finalcleaning of the exhaust gases.

For even greater thermal efficiency and where inertisation isrequired we use Exhaust Gas Recycle, a special dryingtechnique that can be applied to all our airstream dryingsystems. Inertisation is achieved by the reduction of theoxygen content in the drying gas. Here a major proportion ofthe exhaust gases are recycled back into the direct fired airheater. Automated control is incorporated to vary the quantityof recycle gas (via actuated dampers) depending on dryer load.

CoolersPneumatic coolers are a simple and reliable method of coolingand conveying dried product. In many instances ambient airwill achieve the desired cooling effect. Where required, greatercooling capacity and a finer degree of control can be achievedwith conditioned air at controlled humidity and temperature.

Flash Dryers and Coolers

Two flash dryers rated for 15 t/h evaporation

Typical Flash Dryer

ExhaustFan

Feed

Product

Heater

Steam

BagFilter

Sling

Condensate

AirInlet

Mixer

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The Ring Dryer employs the same basic principle as the flashdryer in that the material to be dried is dispersed andconveyed through the dryer in a hot air stream. However theRing Dryer incorporates a centrifugal classifier (either full orsimplified) which allows selective internal recirculation ofsemi-dried solids, effectively lengthening the retention time oflarger particles in the dryer, while finer material, which driesmore rapidly, exits the dryer with the exhaust air.

The heart of the system is the Manifold Classifier which usesdeflector blades to select and classify airborne particles basedon individual densities. By centrifugal action, wetter (and thusheavier) particles follow the manifold contours more closelythan the lighter and drier fractions which are carried alongwith the airstream. The blades are adjusted to direct thelighter, drier particles out of the dryer for collection, while thelarger, heavier particles are recycled through the ring duct foran additional pass of drying.

Ring Dryers may be fitted with in-line disintegrator millswhere de-agglomeration and a degree of particle sizereduction is desired. Drying air with airborne recycledmaterial continuously enters the disintegrator, located at thebase of the drying ring, and provides for effective drying ofdifficult materials at higher capacities. The combined effect ofthe disintegrator and manifold assures excellent particle sizecontrol together with efficient and even drying.

For selective airborne product recycling without additionalmilling, we use our ‘P-type’ Ring Dryer with top recycle loop,via a simplified manifold, recycling the heavier material backinto the warm air stream. Several different configurations ofRing Dryer are available to suit a wide range of products,drying requirements and site conditions. Examples of this areour Low Melting Point (LMP) and Feed Type dryers.

Low Melting Point (LMP) DryerThe LMP dryer is a special Ring Dryer designed to handle,without thermal damage, materials that are extremely heatsensitive or have a low melting point. The wet material isintroduced into a stream of warm recycle air, which carries it tangentially into a drying chamber incorporating a centralhot air inlet. The hot air diffuses slowly into the swirlingstream of recycle air, so that the product is gently heated andnever subjected to the full dryer inlet temperature. In this waylow temperature drying with maximum efficiency is assured. The LMP Ring Dryer can be used for metallic soaps, stearatesor plastics, amongst other products.

Feed Type Ring Dryer.The Feed Type Ring Dryer incorporates a top bend andsimplified manifold, with the heavier material recycled via a chute into the wet feed disperser. This dryer is capable ofevaporation rates up to 20 t/h, utilising maximum gas inlettemperatures of 650ºC. The Feed Type Ring Dryer has beensuccessfully used for waste products, sludges, animal feeds,organic fertilisers and chemicals.

Ring Dryers

Ring dryer with full manifold for vital wheat gluten

TypicalRingDryer Scrubber

Feed

Air Inlet

Fuel

Disintegrator

Product

Manifold

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Fluidised Bed Dryers and Coolers

Our Fluidised Beds are in widespread use throughout theprocess industries for drying, cooling and calcining ofpowders, crystals and granules.

Materials processed in a Fluidised Bed Dryer or Cooler float on acushion of air or gas. The hot or cold air is supplied to the bedthrough a special perforated distributor plate and flowsthrough the layer (or bed) of solids at a velocity sufficient tosupport the weight of particles in a fluidised state. Bubblesform and collapse within the fluidised bed of materialpromoting intense particle movement. In this state, the solidsbehave like a free-flowing boiling liquid. Very high heat andmass transfer values are obtained as a result of the intimatecontact with the solids and differential velocities betweenindividual particles and the fluidising gas.

The design of the distributor plate ensures that the fluidisinggas is evenly distributed across the area of the bed. The gasvelocity is such that only the very fine material fraction iscarried over to the dust collection equipment. A highturndown ratio of production capacity is possible andfluctuations of the feed rate are easily absorbed. In most casesthere are no moving parts in contact with the product.

Fluidised Beds can also be built with:

• drying and cooling zones in the same unit

• multiple stages for drying and conditioning of heatsensitive materials

• exhaust gas recycle, either between sections or full recyclewhen, for example, toxic materials are processed.

Two fluid bed dryer/coolers for sand

Fluid bed cooler for sugar incorporating cooling tubes

Vibrating fluid bed dryer for cooked grains

Fluid Bed with in-bedtubes & gas recycle

DryProduct

DryProduct

Recycle

Steam

Steam

Tubes TubesWater

Condensate

CoolerSection

Feed

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Contact TubesA deep fluidised bed fitted with contact tubes offers significantimprovements in three key areas: emissions, plant size andoperating costs. Up to 90% of the heat can be supplied (drying)or removed (cooling) by the steam or fluid circulating throughthe tubes. The result is an enormous reduction in airflowcompared with the typical standard fluidised bed plant. Contactfluidised beds are best suited to non-cohesive materials.

Vibrating BedsMany materials begin at or pass through a sticky, softening orcohesive phase during processing. Vibrating beds are extremelyeffective in keeping the material in a live fluidised state duringthis transitory phase. They are also suitable for materialswhich have a wider particle distribution.

Stirred BedsWhere materials at the feed point are particularly sticky, arotating agitator can be incorporated within the first dryingsection of the bed. This slow moving device serves to gentlyagitate the wet material, encouraging even fluidisation andeliminating ‘rat-holing’ without causing particle degradation.

High Temperature Fluid BedsA range of thermal processing systems is also available for theuniform heat treatment and cleaning of metallic parts,reclamation of foundry sands, de-coating of recyclable scrapmaterials and calcination. While the operating principle isgenerally similar to our standard static fluid beds, in manycases it is the heat transfer medium, at temperatures up to1200ºC, that is fluidised rather than the product. The bed has a high thermal capacity which ensures accurate temperaturecontrol and a rapid uniform heat treatment of the product.

Combined fluid bed dryer/cooler for minerals

High temperature fluid bed calciner with integralcontact fluid bed cooler for catalyst

Fluid Bed dryer withstirrer & cooler section

DryProduct

Scrubber

Heater

Steam

Stirrer

WaterCoolerSection

Feed

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Rotary Dryers Coolers and Calciners

DryersThe Rotary Dryer is extensively used throughout the processindustries and is highly reliable under the most arduousoperating conditions. It is notable for its flexibility and heavyconstruction and is frequently described as the ‘workhorse ofthe industry’.

Most types operate on the principle of lifting and showeringthe product through a hot gas stream moving either in parallelor counter-flow. Rotary dryers handle a vast range of materialsbut are particularly suited to heavy products and longretention times. Their robust construction also favoursapplications where very high temperatures are permissibleand where the product size is extremely variable. Even withhigh moisture products, pre-treatment of the feed material isnot normally required.

For hazardous products, or simply saving energy, exhaust gasrecycle can be specified here as with our other Airstream DryingSystems. In addition, for the highest moisture content applications,our full range of feed conditioning systems is available.

Typical rotary dryer internals

Rotary dryer with pneumatic exhaust

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In the indirectly heated dryer there is little or no contact betweenthe product and the drying gases since heat transfer is mainly via the cylinder wall. This design is therefore moreappropriate for fine, dusty materials, including thosenecessitating an inert atmosphere, or for applications wherecontamination is to be avoided.

CoolersRotary coolers are supplied in two basic forms - the counter-flow cascade type, which operates on the same principle as thedryer, but requires ambient or chilled air and the indirect typewhich uses recirculated cooling water, either sprayed on theoutside of the drum, or circulated through internal channels.

The cascade cooler is widely used for coarse and granularmaterials, whereas the indirect water cooler is more suitablefor the gentle handling of high temperature, fine and dustyproducts discharged from kilns, calciners and ovens.

CalcinersMany processes requiring a chemical or physical reaction, orchange of state, are carried out in rotary calciners.

These are usually direct-fired and refractory lined for thehighest temperature applications, but may be of the unlined,directly or indirectly heated type for lower calciningtemperatures.

Combined dryer, calciner & coolerDryer internals for crystalline product

Rotary pre-dryer/dryer

Rotary Dryer

Typical Rotary Dryer

DryProduct

ExhaustFan

GasRecycle

Fines

VenturiScrubber

Feed

Heater

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The Rosinaire™ is well suited for the drying of toxic substancesand for the evaporation and recovery of solvents. It has alsobeen successfully used for heating, calcining and cooling. The material is maintained in an agitated state inside theRosinaire™ by a horizontal rotating shaft fitted with adjustablepaddles which keep the product in contact with the internalsurface of the shell. The heating or cooling media (gas orliquid) circulates in an outer vessel jacket.

High heat transfer coefficients are achieved through intimatecontact between the material particles and the vessel wall. A small gas stream is drawn through the system to carry awaythe evaporated water or solvent vapour.

The Rosinaire™ paddles can be adjusted to provide variablematerial residence time – up to typically 20 minutes. The unitsare available in a range of standard sizes up to 2.1m diameterand 15m jacketed length. Systems often utilise full nitrogenrecycle and incorporate condensers and heaters.

Rosinaire Paddle Dryer Column Dryers and Coolers

Column DryersThese are normally used for drying essentially free flowingmaterials such as amorphous or crystalline powders andgranules to very low residual moisture or volatile content. Due to the long retention times possible, these columns arefrequently used for diffusion controlled processes or purgingproducts (e.g. catalysts) of residual monomers.

Many units have been supplied for drying of polyester andnylon chips.

Column dryers have been designed for plug flow and have a special gas distribution cone to ensure uniform counter-current gas flow up through the material. The effectiveness ofthe Barr-Rosin design allows us to specify very low gas flowrates thereby achieving extremely low operating costs. This isespecially important when the process gas is nitrogen, steamor other treated gas. Residence time can vary from 1 to 24hours, depending on the diffusion rate of moisture throughthe material. Heating coils may be incorporated to enhancethermal input to the material.

Column coolersColumn coolers are similarly suitable for free-flowing powders,crystals and granules.

Barr-Rosin Column Coolers transfer 90-100% of the heat to cooling water flowing through tubes suspended across avertical column of slowly moving hot material. In some cases,the heat transferred to the cooling medium can be utilisedelsewhere in the plant. The column is designed as a mass flowvessel giving uniform residence time and even cooling to allthe solids. A small counter-current flow of gas passing upthrough the material can add a convective component toincrease the overall process efficiency and provide a smoothrunning operation.

The Column Dryer and Cooler has no moving parts, other thanthe feed and discharge conveyors and the water recirculationpump. It is simple and reliable – an ecological and economicalanswer to the problem of cooling hot bulk solids.

Rosinaire dryer for PVA

Closed circuit Rosinairewith 2nd stage column

Cooler

Steam ColumnDryer

Pump

Condensate

Condensate

Feed Steam

Product

Solvent

ScrubberCondenser

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Barr-Rosin has extensive pilot plant facilities, located in theUK and Canada. This enables comprehensive testing of clients’materials on the full range of equipment offered by thecompany. A well equipped laboratory is also located on eachsite to provide rapid analysis of moisture contents, bulkdensity and particle size distribution. For more specialistanalyses local laboratories are used.

In addition to the equipment available in our test facilities, anumber of units (as identified below) are available for hire foron-site testing. In addition, we would be pleased to supplystandard or specialist units for clients’ own pilot plants.

The equipment available includes :-

• Two 50mm ring/flash dryers, one with direct gas firedheater, disintegrator and cyclone/bag filter productcollection and the second with electric heating,disintegrator and cyclone/bag filter dust collection.

• 50 mm open circuit ring dryer, fitted with electric heating,disintegrator and cyclone. This unit is skid mounted for use at clients’ sites.

• 100 mm ring dryer with open circuit and full recyclecapability, fitted with electric heating, disintegrator, bagfilter, backmix facility for feed conditioning andcondenser. The complete system is certified for explosionproof environment and capable of operating withnitrogen. This unit is skid mounted for use at clients’ sites.

• 150 mm ring dryer with direct gas fired heater,disintegrator, backmix facility for feed conditioning andcyclone product collection system. This unit is skid mountedfor use at clients’ sites.

• 300 mm diameter static batch fluid bed dryer/cooler fittedwith indirect electric heating, bag filter product collectionand optional stirrer.

• Two 300 mm diameter vibrating batch fluid beddryer/coolers, one fitted with direct gas fired air heatingand cyclone/bag filter combined product collection; theother with electric heating and cyclone dust collection.

Pilot Plant

• Static continuous fluid bed dryer (230 x 910 mm), withoptional cooler (200 x 800 mm), fitted with electric heatingand independent dryer and cooler bag filter productcollection. This unit is skid mounted for use at clients’ sites.

• Non-tubed column dryer fitted with gas dehumidificationand electric heating. This unit is skid mounted for use atclients’ sites.

• Column dryer/cooler with internal contact heat transfertubes, fitted with heating/cooling water distributionmanifold and control valves, activated discharger and thefacility for purge gas. This unit is available for hire at clients’ sites.

• Rosinaire™ dryer/cooler fitted with feed hopper, variablespeed discharge screw conveyor and explosion proofmotor, allowing for use with hydrocarbon solvents.

• 600mm diameter direct fired rotary dryer capable ofoperating in co-current or counter -current mode, fittedwith product feed hopper and variable speed screwconveyor and cyclone product collection system.

Rotary dryer pilot plant

Pilot plant ring dryer manifoldRosinaire dryer pilot plant with partially extracted rotor

GEA is a global technology company with multi-billion euro sales operations in more than 50 countries. Founded in

1881 the company is one of the largest providers of innovative equipment and process technology. GEA is listed in the

STOXX® Europe 600 Index. In addition, the company is included in selected MSCI Global Sustainability Indexes.

We live our values.Excellence • Passion • Integrity • Responsibility • GEA-versity

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