This document discusses different types of dryers and drying processes. It describes spray dryers, oven dryers, freeze dryers, vacuum dryers, rotary dryers, and drum dryers. For each type of dryer it provides a definition, describes the drying process, and lists some common applications. The key information provided includes how each dryer works by removing moisture from materials using methods like applying heat, reducing pressure, or rotating materials to facilitate drying.

1. DRYERS and DRYING PROCESS

2. Drying An operation in which a liquid, usually water, is removed from a wet solid in equipment termed a dryer.

3. Dryers Spray dryer Oven dryer Freeze dryer Vacuum dryer Rotary dryer Drum dryer

4. I. Spray dryer a device used in spray drying can dry a product very quickly compared to other methods of drying

5. Spray dryer

6. Spray drying a method of producing a dry powder from a liquid or slurry by rapidly drying with a hot gas use some type of atomizer or spray nozzle to disperse the liquid or slurry into a controlled drop size spray

7. Spray drying process ATOMIZATION HEATED GAS STREAM SEPARATION

8. A=Solution or suspension to be dried in B=Atomization gas in 1= Drying gas in, 2=Heating of drying gas 3=Spraying of solution or suspension 4=Drying chamber 5=Part between drying chamber and cyclone 6=Cyclone 7=Drying gas is taken away 8=Collection vessel of product, arrows mean that this is co-current lab-spray dryer

9. Applications (Spray drying) Food: milk powder, coffee, tea, eggs, cereal, spices, flavorings Pharmaceutical: antibiotics, medical ingredients, additives Industrial: paint pigments, ceramic materials, catalyst supports

10. II. Oven dryer/ kiln A kiln is a thermally insulated chamber, or oven, in which a controlled temperature regime is produced

11. Oven drying A drying oven is a device for applying low heat over a long time to a variety of objects for a variety of purposes

12. Oven drying process

13. Applications (Oven drying) toilet bowls, sewer pipe, tiles, and glassand porcelain. manufacture of chlorine gas curing of rubber and plastics

14. III. Freeze dryer A device used for freeze drying The result is a product that can be stored at room temperature for years without spoilage, or packed in limited storage spaces and reconstituted with water later

15. Freeze drying also known as lyophilisation is a dehydrationprocess typically used to preservea perishable material or make the material more convenient for transport.

16. Freeze drying process Cooling Vacuum chamber sublimation

17. Applications (Freeze drying) Pharmaceutical companies often use freeze-drying to increase the shelf life of products Food: instant coffee, astronaut food, freeze- dried fruits, cereals Technological industry: freeze-drying is often reserved for materials that are heat-sensitive, such as proteins, enzymes, microorganisms, and blood plasma

18. IV. Vacuum dryer can be used for delicate materials and save up significant energy quantities due to lower drying temperatures

19. Vacuum drying Vacuum drying is a process in which materials are dried in a reduced pressure environment, which lowers the heat needed for rapid drying. It does not take place in a true vacuum, despite the name

20. Vacuum drying process

21. Applications ( Vacuum drying) commonly used for drying thick hard wood and other materials

22. V. Rotary dryer A rotary dryer is a device that uses rotation, gravity and warm gasses to dry a material

23. Rotary drying A direct heated dryer uses the combustion gases generated by the heater mixed with an artificially heated gas. This second gas is nearly always common air, but it can be any inert gas.

24. Rotary drying process

25. Applications (Rotary drying) A rotary dryer is a device that uses rotation, gravity and warm gasses to dry a material. These driers range from small household clothes dryers to large industrial systems. Regardless of their size, the majority of rotary dryers work the same way.

26. VI. Drum dryer adrum dryer is a rotating cylinder that uses steam or hot air to heat feedstockand reduce the moisture content during a manufacturing process

27. Drum drying Depending upon the products it will be processing, a drum dryer is typically made from cast iron or stainless steel. The length of time the feedstock remains on the drum depends on the original moisture content and the desired ending moisture content

28. Drum drying process

29. Application (Drum drying) Powdered milk, starches, breakfast cereals, baby food, instant mashed potatoes