Pneumatic Dryer

Convey your material through a heated oven section that removes moisture by evaporation.

Flash dryers offer an effective and efficient method of removal of surface or on bound moisture from a feed product. Flash dryers are pneumatic driers having very low residence time within the equipment, thus flashing off the moisture from the feed. They are used for efficient drying of moist powders. slurries, filter cakes, granules, etc. They operate on varying throughput rates from few hundred kilograms per hour to hundreds of tons per hour. Low temperature dehumidified air could be used for heat sensitive products to hot gases with temperature upto 500 - 600 deg. C. for temperature resistant products. Flash dryers comprises of the feeding section normally a screw feeder, rotary valve, vibratory feeder, etc. which feeds the wet product in a controlled fashion into the throat of the flash drier, where it is mixed with hot air produced by a hot air generator or heat exchanger.

I have experienced very limited success with conveyor drying as the process is limited to drying only the exposed surface leaving the under lying powder unaffected. The thorough put is also not good. After several trials I have found the flash drying is very fast and extremely effective for dehumidification.

Tkanks for your reply. My material is SBS Sodiam bita sulphonate. In flash dryer there is disperser , Venturi ,Air heater ,Hot air box. I want to know how much temperature of air should be kept to dry this material . This material is like clay having 15% moisture.Any design Or any literature which can help me to deisgn this dryer .

You have to get a professional advise. Also the design of flash dryer involve some critical issues that can can be addressed only through trials. My suggestion would be to work with a company specialised in drying equipment.

Yep. Field trials with a pilot scale unit is the only way to go. Are there any manufacturers with suitable pilot units who want to play ball?

I appreciate your response.

Most reputed manufacturers of drying equipment offer pilot/field trials services as an essential prerequisite in powder drying process to arrive at operating parameters.

To get an idea of the thermal input needed, take 13% (15-2) of the weight per time of your material, multiply by about 1000 Btu/h for vaporizing the water, and further multiply by about 1.3 as a safety factor (some of the hot air will blow through without full heat exchange with the material). The 1.3 factor is a bit of a guess, and would depend on further specifics of the design.

You may want to investigate microwave drying. Microwaves can be tuned to selectively heat water molecules without raising the temperature of your product.

Can we dry this material using screw ribbon mixer having length 4-5meter & which is having steam jacket. But How much heat & residence time is requiered to dry this material in conveyor .