INTRODUCTION

On average, each person produces 58 grams of dried sludge per day. 6.9 million dry tons of municipal sewage sludge was produced in 1998, this figure will grows up to 7.6 million tons in 2005 and 8.2 million tons in 2010 (Biosolids Generation, Use, and Disposal in the United States , http://www.epa.gov/epaoswer/non-hw/compost/biosolid.pdf). There are more than 15,000 wastewater treatment plants in the USA

( http://www.srs.fs.usda.gov/pubs/viewpub.jsp?index=1050).

GENERATION, USE AND DISPOSAL OF BIOSOLIDS IN THE PAST AND FUTURE

Biosolids (historically known as sewage sludge) are the solid organic matter produced from wastewater treatment processes that can be beneficially used, especially as a soil amendment. Biosolids producing is inevitable, so we have to deal with properly.

There are two ways to treat sludge: one is to use it beneficially as land application; one is to dispose it, such as incinerating or landfill. In North America, dumping into the sea and river was prohibited, and landfill is becoming more and more difficult, especially in east of America. Because of sludge has high content of pathogens, so residents sued sludge transportation companies for their dumpling sludge (http://www.organicconsumers.org/Toxic/floridasludge.cfm). So we can only use it as land application or incinerating.

If we want to use it beneficially, that is to use it as land applications, it has to meet The Part 503 Biosolids Rule.

The Part 503 Biosolids Rule divides biosolids into “Class A?and “Class B?biosolids in terms of pathogen levels. It also imposes a vector attraction reduction requirement, providing specific alternatives for meeting the requirement. Class A biosolids must undergo treatment that reduces pathogens (including pathogenic bacteria, enteric viruses and viable helminth ova) in the biosolids below detectable levels. Once these goals are achieved, Class A biosolids can be land applied without any pathogen-related restrictions at the site. Class A biosolids (but not Class B) can be used as bagged biosolids marketed to the public. Some of the treatment processes described earlier, such as composting, heat drying, and high-temperature aerobic digestion, can meet the Part 503 Biosolids Rule Class A pathogen reduction requirements if they are conducted to meet operating conditions also specified in the rule. Biosolids having the least further restrictions on beneficial use are those meeting the Class A pathogen and vector attraction reduction requirements, and the high-quality pollutant concentration limits for metals. Once these requirements are met, the biosolids can be used with no more restrictions than any other fertilizer or soil amendment product (http://www.epa.gov/epaoswer/non-hw/compost/biosolid.pdf).

Class B biosolids ensure that pathogens in biosolids have been reduced to levels that are protective of public health and the environment under the specific use conditions. Site restrictions apply to Class B biosolids, which minimize the potential for human and animal contact with the biosolids until environmental factors have reduced pathogens to very low levels. Class B biosolids cannot be sold or given away in a bag or other container for land application at public contact sites, lawns, and home gardens. Class B biosolids can be used in bulk at appropriate types of land application sites, such as agricultural lands, forests, and reclamation sites, if the biosolids meet the limits on metals, vector attraction reduction, and other management requirements of Part 503 (http://www.epa.gov/epaoswer/non-hw/compost/biosolid.pdf).

In Europe, the regulation is even strict than in the USA, for landfill will be closed to waste with more than 5% of organic content in 2005. Landfill is also banned in some states in the USA (http://www.ocsd.com/civica/filebank/...sp?BlobID=3165).

According to estimation, about 60% of biosolids were beneficial used (41% land application; 12% advanced treatment; 7% other benefical use.), 40% of biosolids were disposed (http://www.epa.gov/epaoswer/non-hw/c.../biosolid.pdfs Generation, Use, and Disposal in The United States http://www.epa.org ). The situation is similar in Western Europe. All sludge was incinerated in Japan.

A variety of factors have influenced biosolids generation and use over the years. Advancements in wastewater and biosolids treatment technologies, including wastewater pretreatment, pollution prevention programs, and population growth, have resulted in increased volume of higher quality biosolids. Increases in biosolids amount and improvements in quality are only part of the story, however. Federal and state regulations and guidance, in particular the Part 503 Biosolids Rule, have encouraged recycling and use of biosolids rather disposal. Additionally, a number of factors have contributed to increased to increase biosolids use. These factors include outreach and marketing efforts, high costs for disposal of biosolids in some locations, bans on disposal of biosolids in landfills, landfill capacity concerns, closures of landfills following implementation of landfill regulation, bans of yard trimmings in landfills, and continuing research into the safe beneficial use of biosolids. So according to estimation, about 70% of biosolids were beneficial used (48% land application; 13.5% advanced treatment; 8.5% other beneficial use.), 30% of biosolids were disposed (10% landfilled, 19% incinerated; 1% other treated.) in North America (http://www.epa.gov/epaoswer/non-hw/compost/biosolid.pdf).

For land application, the wet sludge has to be composted or dried in order to produce Class A biosolids, that is to eliminate pathogens from wet sludge. In this application, drying process is necessary, for it can eliminate pathogens from wet sludge during drying process with high drying temperature. It can also reduce shipping fee by drying, for it reduces its volume to 1/3, its weight to 1/5 respectively.

There are some potential barriers to increase beneficial use of biosolids, such as, public acceptance, odors, environmental and health concerns, liability concerns, costs, crop consideration, etc. the land application for Class B will be more and more difficult. New Jersey, California, Arizona, etc. have developed, or are in the process of developing, ordinances that severely restrict or ban the land application of Class B biosolids. Recently Kern and Kings Counties banned land application of Class B biosolids. It has become clear that future requirements for managing biosolids will be more restrictive and costs will increase as current options are eliminated. Therefore, the Orange County developed their Long-Range Biosolids Management Plan (http://www.ocsd.com/civica/filebank/...sp?BlobID=3165). They wanted to develop a sustainable, reliable, and economical program for long-range biosolids management.

Even for Class A biosolids, it needs to be dried in order to reduce its tipping fee. In the past 3 years, the tipping fees for biosolids land application have risen from $25 per wet ton (pwt) to $35 pwt, representing an increase of 40 percent. In the interim period, the tipping fee is expected to increase to $45 to $50 for Class A biosolids land application. The current biosolids cake solids concentration is in the range of 20 to 22 percent, resulting in a cost of $200 to $250 per dry ton (pdt) for Class A biosolids land application.

Therefore, the Orange County focuses on more reliable Orange County and Southern California beneficial use markets through developing high-value products by:



1. Composting;

2. Heat drying;

3. Energy recovery;

4, Organo-mineral fertilizer manufacturing.

For incinerating, fluid bed incinerator is the best suitable way for sludge incinerating for its features over multiple hearth incinerator. It is better to dry sludge before incinerating, for the dried sludge can be also used as fuel for brick kilns, cement kilns, and coal-fired power plants. It is also a better way to incinerate in fluid bed incinerator for a lot of advantages over incinerating wet sludge directly, such as no additional fuel, no heat recovery for incinerating system, easy to operation, independent of the influence of the change of water content, etc.

There will be only two main ways to deal with municipal sludge: to dry it as fertilizer; to incinerate or use as fuel as other applications. Drying process will be necessary for both ways.

DRYING EQUIPMENT AND COMPANIES

There are about ten kind of sludge drying equipment and over 50 sludge drying company in the world. Foreign companies dominate America sludge drying market.

There are following kinds of sludge drying equipment in the world:

Triple pass rotary dryer;

Rotary dryer with smashing device;

Disc dryer;

Paddle dryer;

Tray dryer;

Fluid bed dryer;

Belt dryer;

Rotary dryer;

Solar energy dryer.

Following are brief introduction on five best selling sludge drying equipment and its company.

1, Triple pass rotary dryer

Triple pass rotary dryer was developed by Andritz Group, Baker-rullman, etc. and uses it to dry sludge. Andritz Group is the leading company in sludge drying field. They have over 40 projects in the world and developed several drying system on the basis of triple pass rotary dryer. They also developed sludge drying and incinerating with triple pass rotary dryer. Andritz Group also develop fluid bed dryer and belt dryer to dry sludge

((http://www.andritz.com/ANONIDZ22577E...s-general.htm, Energy-Efficient Sludge Drying,

http://www.javaram.com/upload/papers...geDrying.PDF,

Selection and Sizing of Thermal Drying Facilities,

http://www.sc-ec.org/PDFs/2002SCEC/5...d%20Sizing.pdf).

Triple pass rotary dryer like conventional rotary dryer, can only dry granular materials, so they have to mix dried sludge with wet sludge first in order to produce granular sludge. In their sludge drying system, they have to use screener, crusher, mixer, etc. So their sludge drying system is very long and capital cost is very high. Its capital cost is about $7 MM for 8,800 lbs of water evaporation rate (its capital cost increases to $ 11 MM last year).

Triple pass rotary dryer has the highest efficiency in energy utilization among the existing sludge drying equipment. It only costs 1400 BTU to evaporate one pound of water (according to calculation based on its process parameters in Tampa facility, it costs 1500 BTU to evaporate one pound of water).

2, Rotary dryer with smashing device

Rotary dryer with smashing device was developed by Okawara Mfg. Co., Ltd.

In Japan, nearly 100% of sludge is incinerated after drying. So Okawara Mfg. Co., Ltd only uses rotary dryer with smashing device to dry wet sludge to 30 to 40% of water content, then incinerate dried sludge.

Up to now, 480 units of this dryers are applied to human waste and sewage treatment plants; 40 units to drinking purification plants; 1,200 units to other industrial factories

( see http://nett21.gec.jp/JSIMDATA/WASTE...l/Doc498.html).

The rotary dryer with smashing device is ideal drying equipment if the dried sludge is incinerated to provide energy for drying system.

First, it is very simple. The system only needs dryer, incinerator, cyclone, offgas treatment.

Second, it does not need additional energy.

Third, the size and its distribution of dried sludge are right for fluid bed incinerator. Fluid bed incinerator can incinerate low thermal value of fuels.

3, disc dryer

Disc dryer was developed by Atlas-Stord to dry sludge. Atlas-Stord has more than 20 years of experience in sludge drying business and has more than 100 sludge drying installations ( http://www.atlas-stord.com/showpage.asp?ID=152).



Atlas-Stord’s RotaDisc?Drier can dry sludge partly or fully. Partly dried sludge can be used immediately as fuel/ energy source in incinerators or can be used for alternative waste handling. In this drying system, it needs to mix the dried sludge with the wet sludge, which is same as triple pass rotary dryer

(http://www.atlas-stord.com/?id=73, http://www.atlas-stord.com/?id=74).

Disc dryer is similar to rotary dryer, but it requires mixing wet sludge with dried sludge.

4, paddle dryer

Paddle dryer was developed by Nara. Komline-Sanderson Engineering Corporation has exclusive license to manufacture paddle dryer in North America. Paddle dryer has been applied to dry sludge in numerous wastewater treatment plants in North America and in the world.

The paddle dryer is an indirect heat transfer drying equipment which utilizes a high degree of mechanical agitation to enhance contact with the product being dried. Dual counter-rotating shafts with unique intermeshing wedge-shaped paddles produce intimate mixing, optimize heat transfer, and provide a self-cleaning feature.

This kind of dryer needs steam or thermal oil, that is: it needs steam boiler or thermal oil boiler. Its efficiency in energy utilization is not as high triple pass rotary dryer. It costs about 1500 BTU to evaporate one pound of water (it costs 1600BTU or more to evaporate one pound of water, considering the efficiency in energy utilization for steam or thermal oil boiler).

Its dried sludge is powder and paddle dryer is lowest in capital cost. So it is suitable dryer for small treatment.

5, tray dryer

Tray dryer was developed by Seghers to dry sludge. It is a dryer and pelletizer at the same time

(http://www.segherskeppel.com/sk/home...256CC6003539CD ).

It has applied in 8 projects in the world

(http://www.segherskeppel.com/sk/home...stAll?openform ).

This dryer is indirect heating dryer. It needs steam or thermal oil to dry sludge, just like paddle dryer. Because its low heat transfer effect between heating media and wet sludge, it needs bigger heating transfer area. So its volume is huge for large treatment. And its structure is complicated, therefore it is the most expensive sludge drying equipment in the world. Its capital cost is about $7.5 MM for 8,800 lbs of water evaporation rate.

It uses steam or thermal oil, just as paddle dryer. Its efficiency in energy utilization is not high; it costs about 1500 BTU to evaporate one pound of water (it costs 1600BTU or more to evaporate one pound of water, considering the efficiency in energy utilization for thermal oil boiler). Those are the reasons why this kind of sludge dryer only has 8 projects in the world.

dryruntech@yahoo.ca ■

There are two kind of vibrating fluid bed dryer:Horizontal Vibrating Fluid Bed Dryer and Vertical Multi Layer Vibrating Fluid Bed Dryer. Vertical Multi Layer Vibrating Fluid Bed Dryer can also be used to roast various kinds of nuts in food industry.

Horizontal Vibrating Fluid Bed Dryer

Solid materials move straightaway in Horizontal Vibrating Fluid Bed Dryer mainly due to vibration. Vibrating fluidized bed can be used for drying or cooling process. It is suitable for the following conditions: material particles are too big or irregular to be fluidized, lower speed of fluidization is required to keep particles complete, materials are sticky or sensitive to temperature. Since the thickness of particle layer is not more than 200mm in vibrating fluidized bed while it can reach 1500mm in non-vibrating one, the residue time of particles in per unit area is much shorter compared with non-vibrating fluidized bed.



Vertical Multi Layer Vibrating Fluid Bed Dryer/Roaster

In Vertical Multi Layer Vibrating Fluid Bed Dryer/Roaster, the materials move forward in circle motion in each layer, and then drop down to another layer below. The hot air goes through the perforated distributor plate from bottom layer to top layer. Therefore, the flow of materials and hot air is in counter-flow. The materials are dried first by low temperature air, roasted by high temperature. The temperature drop is bigger than usual roaster. The materials move forward at the same angle speed in each layer, so its detention time is same. Therefore, its roasting quality is the best comparing to the other roasting equipment existing, over-roasted or under-roasted never happens in this equipment.

Vertical Multi Layer Vibrating Fluid Bed Dryer has many virtues such as high efficiency of heat, small base area, and so on. It can be used for food to accomplish drying and baking processes. Roasting at the same equipment.





FEATURES

Less energy consumption: 30% heat and 40% electrical power are saved compared with the similar equipment.

Continuous: The material is fed and discharged continuously.

High efficiency: Vibration intensifies heat and mass transfer, which results in less time and higher efficiency for drying.

Wide usages: By changing velocity of airflow steplessly in definite range, the resident time of material can be adjusted to adapt to various materials.

Lower noise, better vibration absorber, placement on the ground without fixing, long useful life.

Material can be fed automatically.



APPLICATIONS for Horizontal Vibrating Fluid Bed Dryer - Partial Listing

Ammonium Sulphate

Animal Feed

Botanicals

Bran Puffed Rice

Breadcrumbs

Brewer's Grain

Bromine Derivate (TBBA)

Butyl Rubber

C.M.C.

Calcium Chloride

Cat Litter

Cereal

Cheese (Cheese Powder)

Cheese Pieces

Chemicals

China Clay

Chocolate

Chocolate Beans

Chopped Glass Fibers

Chromic Acid

Clay Pellets

Clay Sludge Pellets

Coconut Shells

Compost

Corn Grain

Corn grit

Crumb

Crystals

DDGS [Distillers Dried Grains and Solubles]

Detergent

Dextrose

DSMA (herbicide)

Fertilizer - Granulated/waxed

Fertilizer Products

Fiberglass

Fibers

Food Products

GDL

Grains

Granite

Granitsplit

Gypsum

Gypsum Waste

Haisol NPK

Herbs

Hexamine

Iron and Slag of Copper

Iron Oxide

Iron Sulphate

KCl

KCl/NaCl/K2SO4

KGA

Lactitol

Lactose

Leaves

Limestone

Limestone and Sand

Meat

Milk Products

Municipal Sludge

Na2SO4

NaCl

NaCl (from fluegas treatment)

Natrium acetate

Natrium formiate

Natriumpercarbonate

NH4 Cl

NH4 SO4

Nuts

Orange Peel

Paper Sludge

Paprika

Peanuts

Pepper

Pharmaceuticals

Plasma

Plastic Granulate

Plastic Starch

Polymer

Potash

Potassium Nitrate

PVB

PVC

Rasped Potatoes

Rice [100's of varieties]

Rice Conditioning

Rock salt

Rubber

Rubber Pellets

Rusk

Rusk Biscuits

Rusk/Breadcrumb

Salt

Salt - Evaporated

Sand

Silica Gel

Slag

Slag Sand

Soy Beans

Soy Meal

Spices

Steel Slag

Stems

Sugar

Sugar extrudate

Sulphanilic Acid

Talcum Pellets

Tobacco

Tomato Pulp

Twaron (Kevlar) Pulp

Vanadium Oxide

Vegetables

Vitamins

Washed Plastic Granules

Waste Products

Wheat

Wheat

Wheat and Bran

White Sugar

Zn/Pb granulate



APPLICATIONS for Roasting with Vertical Multi Layer Vibrating Fluid Bed Dryer Dryers

Cocoa

Peanut

Sunflower seed

Pine tree seed

Snack food



Additional information about Roasting Equipment

The working process of vertical multi layer fluid bed dryer/roaster is as follow:

In vertical multi layer vibrating fluid bed dryer/roaster, the materials move forward in circle motion in each layer, and then drop down to another layer below. The hot air goes through the perforated distributor plate from bottom layer to top layer directly. Therefore, the flow of material being dried or roasted and the gas being used in this system is countercurrent, so the gas contacts several times with material being treated. The materials are dried first by low temperature air, then dried/roasted by high temperature. The temperature drop is bigger than conventional roaster (from 490F to 190F), for it has 5 or 8 layers, depending on process requirement. The materials move forward at the same angle speed in each layer, so its detention time is same. Therefore, its roasting quality is the best comparing to the existing roasting equipment, over-roasted or under-roasted never happens in this equipment.

Vibrating fluid bed dryer/roaster has another advantage: its intensity of mass and heat transfer is much bigger than rotary drum and belt dryer (conveyer dryer) because of fluidization by means of vibrating.

The detention time is adjustable by the number of layer (in design) and installing angle of vibration motor (in operation) according to different drying time and roasting time.

Its capability can be from 40 Kg/h to 1000 Kg/h for drying and roasting process.

It can be used to roast shelled and in-shell nuts without at the same equipment.

dryruntech@yahoo.ca ■

There are following kind of Fluid Bed Dryer being used in the world:¡¡smashing fluid bed dryer, fluid bed dryer with built-in heat exchangers, fluid bed dryer with inertia particles, pulsed fluid bed dryer, and spray fluid bed dryer.

FLUID BED TECHNIQUE

Fluid Bed Technique is most effectively utilized in a number of heat and mass transfer applications like:

Drying

Cooling

Calcinations / Roasting

Carbonization

Reaction

Sterilization

ADVANTAGES

Fluid Bed Techniques have the following advantages:

Intimate contact of hot air and solids result in high heat transfer co-efficient. This makes the drying system compact.

Higher operating temperatures possible because of rapid heat and mass transfer rates.

No overheating of heat sensitive products because of special constructional features.

Unique and thermally efficient design of embedded Heat Exchanger.

Lower capital costs

Easy control of residence time simple to adjust moisture content of dried product.

Easy handling of feed and product.

No moving parts, stabilized operation and negligible maintenance.



CONTINUOUS FLUID BED DRYER

Fluid Bed is designed to dry products as they float on a cushion of air or gas.

The process air is supplied to the bed through a special perforated distributor plate and flows through the bed of solids at a velocity sufficient to support the weight of particles in a fluidized state. Bubbles form and collapse within the fluidized bed of material, promoting intense particle movement. In this state, the solids behave like a free flowing boiling liquid. Very high heat and mass transfer values are obtained as a result of the intimate contact with the solids and the differential velocities between individual particles and the fluidizing gas.

For even greater thermal efficiency is required, recycling of exhaust gases can be used. This can be implemented on all our air stream drying systems and retrofitted on customer's existing drying operations.

Continuous Fluid Bed Dryer units ranging from pilot scale to 200 ft2 (20 m2) have been supplied.

The fluid bed has been used to dry products in many industries including food, chemical, mineral and polymer. A broad range of feed materials including powders, crystals, granules and pellets can be processed.

This technology can also be used for cooling applications; either as a separate unit or combined with drying in a single zoned bed.

CPE drying equipment



FLUID BED DRYER WITH BUILT-IN HEAT EXCHANGER

Heat transfer units (tube or plate type) are built inside the equipment. About 60% - 80% of heat capacity necessary for drying is supplied from the units. Consequently, the quantity of hot air can be decreased, the equipment becomes compact and auxiliary equipment is also miniaturized.

The distributor plate is fixed at the bottom of a rectangular vessel. Hot air is passed through the Distributor plate; wet material is fed into Fluid Bed Dryer continuously by a screw feeder at constant rate. The air velocity can be varied as desired. After lapse of designed residence time, the dried product is continuously discharged at the overflow and underflow outlets. The exhaust air is vented out after processing through a dust separation system.



FEATURES

As wet material fed to the first drying chamber is mixed and dispersed into the residence material, the material with comparatively high moisture content can be also dried.

At and after a second drying chamber piston, flow ability can be obtained by adjusting the numbers of the partition plates according to the required residence period.

The adoption of the discharging method by an overflow gate ensures the easy control of residence period.

The perforated plate with the fixed direction ensures easy discharging.

Due to few destruction of particle, suitable for drying granular or crystallized material.



TYPICAL APPLICATIONS

ABS

Ammonium

Bromide

Chemicals & Fertilizers

Citric Acid

Common Salt

Detergent Powders

Maize

Milk Powder

Pesticides

Pharmaceuticals & Food Stuff

Polyethylene

Polypropylene

Potassium Chloride

PVC

Quartz

Salt

Sand

Sodium Sulphate

Soya

Sugar

Synthetic Resins & Polymers

Tea

Urea

Removing Chemical-bound water from inorganic salts, such as:

FeSO4.4H2O

ZnSO4.4H2O

MgSO4.4H2O

ZnSO4.4H2O

CuSO4.H2O

MnSO4.4H2O

MgCl2.2H2O

AlKSO4.12H2O, etc.



FLUID BED DRYER WITTH INTERNAL PARTICLE

The fluid bed dryer with internal particle is a kind of drying equipment for drying slurry material continuously and taking out the solids dispersed in the slurry with a size of primary particle.

The slurry material is supplied by a pump direct the media particle group (a fluidized bed) being fluidized by a hot air inside the drying tower. The supplied slurry material is dispersed into the fluidized bed through adhering membranously with the surface of the media particle being fluidized actively, and dried by a hot air.

Due to a very large surface area of media particle group, the evaporated moisture inside the slurry material can be dried in a short time. The solids remained on the surface of media particle continuously exfoliate by the mutual contact of media particle and are discharged together with the exhaust air out of the drying tower and collected as dried powder through a cyclone and a bag filter, etc.





TYPICAL APPLICATIONS

INORGANIC SLURRY :

Alumina

Zirconia

Barium Sulfate

Ferrite

ORGANIC SLURRY:

Emulsion resin

Dyes

Pigments

Medicines

Blood plasma

dryruntech@yahoo.ca ■

The following ROTARY DRYERS are widely used in various industry:

----Indirect Rotary Dryer

----Direct Rotary Dryer

----Rotary Dryer with Self-clearance Device

----Rotary Dryer with Disintegrator----Super Rotary Dryer





Rotary Dryer possesses large drying capacity and smooth operation features.

The directly heated rotary dryer operates on the principle of lifting and showering the product through a hot gas stream moving either in parallel or counter-flow.

In the indirect dryer, which is more suited to fine and dusty materials, there is little or no contact between the product and the drying gases since they are heated from the outside, via a stationary jacket fitted with either multiple burners or other external heat source.

The rotary dryer with self-clearance operates on the same principle of conventional rotary dryer. In this new type of rotary dryer, self-clearance device is employed in order to clear up the sticky materials from Internal Lifters. Therefore, it can be used to dry sticky materials and avoid overheated or explosion because of sticky materials stick to Internal Lifters.

The rotary dryer with disintegrator also operates on the same principle of conventional rotary dryer. In this new type of rotary dryer, rotating disintegrator is employed, so it is possible to dry sludge in this new type of rotary dryer. Thanks to the Internal Lifters and Rotating Disintegrator in the drum, the wet materials directly being fed into rotary dryer with disintegrator are carried forward and crushed into small pieces by disintegrator and exposed to the hot gas during falling process. Heat and mass transfer is taken place between hot gas and wet material surface. Large blocks of wet material are broken into small pieces during repeating processes of carrying and falling in order to increase the surface area of wet material. The small particles are dried by hot air, and discharged until desired water content is achieved. The fine powder carried by air is collected by dust catcher.

Noted for their flexibility and heavy construction, rotary dryers are less sensitive to wide fluctuations in throughput and product size.

For greater thermal efficiency is required, recycling of exhaust gases can be used. This can be implemented on all our air stream drying systems and retrofitted on customer's existing drying operations.

Rotary dryers are suitable for a wide variety of products, ranging from granular, powdered and crystalline materials, through to filter cakes and sludge for the food, chemical and mineral industries.



FEATURES

Rotary dryer offers distinct advantages, such as simple & sturdy construction, their adaptability to fluctuating feed rates as well as moisture content of the products.



APPLICATIONS

Chemical Industry:

Dye pigments

Salts

Phosphates

Metal sludge

Fertilizer

Soda ash etc.¡

Petrochemical Industry:

Polymers, such as PVC, HDPE, etc.



Non-Metallic minerals industry:

Clay

Fireclay

Coal

Limestone

Plaster

Sand

Slag



Fodder Production:

Drying Agricultural products such as green stuff, grain, root vegetables etc.



APPLICATIONS for Rotary Dryer with self-clearance device/ disintegrator can dry the following materials

Alfalfa

Antibiotic residues

Bakery waste

Blood

Bone

Canning yproducts

Choline Chloride

Coffee rounds

Composts

Corn obs

Crab & fish scrap

Feather meal

Food processing waste

Forage

Fruit pulp waste

Grain byproducts

Humus

Industrial waste

Manure

Marine vegetation

Meat & poultry byproducts

Municipal sludge

Paper pulp

Parboiled rice

Peat moss

Tomato pomace

Vegetable waste

West/dry corn miller's byproducts

Wood waste.

dryruntech@yahoo.ca ■

SPIN FLASH DRYER





Spin Flash Dryer is a kind of continuous drying equipment that is designed especially for drying caky, pasty and slurry materials. Fresh air for the drying process enters in tangential direction into the drying chamber, which forms strong turbulent whirling airflow with action of the mechanical dasher. The wet materials are fed into the drying chamber quantitatively, smashed and dried by dasher and whirling airflow. The fine powder products are discharged from the top of chamber after being separated by the granularity classification, collected by the latter separator. The other larger ones return to the chamber to be smashed and dried continuously.



FEATURES

Adapted widely to the low viscosity liquid material containing fine granules that don’t dissolve in water or solvent, slurry, pasty, filtered cakes.

The materials need no dilution.

Power consumption is low.

Continuous one step drying operation, compact layout, easy operation and cleanout.

Rapid heat and mass transfer, less heat loss.



APPLICATIONS

Amino Acids

Dyes & Dye intermediates

Pigments etc

Starch

Gluten

dryruntech@yahoo.ca ■

PADDLE DRYER





Paddle Dryer/Processor is a highly efficient, mechanically agitated, indirect heat transfer device for putting heat into or removing heat from a process mass. The heat transfer medium, steam, oil, thermal fluid, water, or glycol is isolated from the process mass. Dual counter-rotating shafts with unique intermeshing wedge shape paddles produce intimate mixing and optimize heat transfer. The use of hollow paddles for heat transfer results in a compact machine. Paddle Dryer can be used for both process/production applications and for drying sludge and biosolids.

All or nearly all of heat capacity necessary for drying are brought by the direct heat transfer from the paddle shafts and the jacket. The hot air is only used as a carrier preventing evaporated vapors from dew formation.

Depending on your specific requirements, XXX can provide you with a dryer, or a complete system. You have the following choices:

Indirectly heated with steam or hot oil:

Steam from 30 to 200 psig (or higher)

Hot Oil up to 750?F

Products having different dryness levels or high discharge temperatures:

Dry to 99+% dry solids

Partially dry to achieve autogenous conditions

Produce a product of any intermediate dryness

Product can approach the temperature of the heating medium

Continuous or batch operation:

Continuous process on a once-through basis

Batch operation with a reduced drying time

Enclosed process:

Atmospheric, vacuum, or pressure designs

Purged systems with solvent recovery

Product discharge by weir or screw conveyor:

Overflow weir allows for constant volume operation

Variable speed bottom discharge screw conveyor

Bottom discharge screw conveyor used for rapid product removal







FEATURES

Compact construction and small installation space.

Big heat transfer coefficient and high heat efficiency.

Self-cleaning effect among paddles.

Easy control of temperature and residence period of processed material.

Material with high moisture content can be processed.

Piston flowability is secured.



APPLICATIONS

Drying (Recovery of solvent), Heating, Cooling.

Synthetic resins

Foods

Industrial chemicals

Industrial and Municipal Sludge

dryruntech@yahoo.ca ■

HEAT PUMP DRYER





Heat pump drying process



The drying process for Heat Pump is different from the thermal drying procedures.

For the thermal drying process, with the help of heat exchangers, large quantities of air is heated up from a low to a high temperature. By this increase in temperature the air due to physical characteristics is capable of taking up moisture. Thus the wet materials are dried. The only way to remove the moisture from the drying chamber is to emit it to the environment. Hence a big disadvantage of this system is the high loss of energy.

The drying principle for Heat Pump Dryer is based on the conservation of energy, i.e. the system is closed. Of course there is a certain loss of energy by radiation, but the drying system itself does not incur any loss of energy. In contrast to thermal drying, the Heat Pump Drying System does not emit warm air loaded with moisture into the environment but leads it back through special heat exchanger systems. Two major steps for this process: the conservation of energy which is in the re-heated air and the dehumidification of the air. The drying system operates on a special dehumidifying principle. Warm, dry and unsaturated air is led over the surface of the parts to be dried. Now the air takes up the water adhering to the surface. Afterwards the water condensates in the dryer with the help of a refrigeration cycle; the air is warmed again. A both ecologically and economically sensible cycle is closed.

The temperatures vary - depending on the product - between 30¡æ and 85¡æ. With this economic dry-air system the hitherto high power consumption can be reduced by up to 80%. Considerable improvements of the drying quality are attained of a wide range of parts and products. Due to the low temperatures, products can be dried gently. This, again, increases the product quality. Sometimes any sort of refinishing work is no longer necessary. Furthermore cycle times can usually be reduced significantly as well.









FEATURES

Small energy consumption because of closed-loop system. One KWH of electric energy can evaporate 3.5 to 4.5 Kg of water.

No temperature load of the articles which can be dried, since the drying temperature between 20¡æ to 40¡æ

Heating of the material, the workpieces, the conveying engineering and the environment is not necessary

There is not a danger of the overheating of the drying property with stop of the conveying engineering

After the drying process, no cooling stretch is necessary

Simple structure of plant, since by the low drying temperatures, an isolation of the dryer housings is not necessary

No discharge of warmth, humidity and harmful air emits into the atmosphere

Always stable drying conditions, independently of the weather

Reduction of the drying times with temperature-sensitive parts



APPLICATIONS

Sludge

Auto parts

Lumber

Chemical products

Agricultural and biological products

Chemical and pharmaceutical products

Solvent recovering from drying process

dryruntech@yahoo.ca ■

Some inorganic salts contain chemical-bound water, such as FeSO4, ZnSO4, MgSO4, CuSO4, AlKSO4, MgCl2, etc. It is easy to agglutinate, therefore it is difficult to use and store. For long distance transportation, it also increases the transporting cost. Therefore, it is necessary to remove chemical-bound water from them. The heating temperature must reach to its melting point in order to remove its chemical-bound water, that is: it must change from solid state into liquor state. So drying oven or spray dryer must be employed in order to remove its chemical-bound water. For drying oven, its energy efficiency is low and its end product has to mill into the required size. For spray dryer, its capital cost is high. Fluid bed dryer can overcome the above disadvantages, but it will agglutinate in fluid bed dryer when it reaches its melting point, for fluid bed dryer can only dry granules. XXX solved the above problem by increasing the height of fluid bed dryer and velocity at special area inside fluid bed dryer. It has been successfully applied into the removing chemical-bound water from the following inorganic salts:

FeSO4

CuSO4,

ZnSO4

MgSO4

AlKSO4

MgCl2

MnSO4

dryruntech@yahoo.ca ■