Industrial dryers

Drying is one of the most frequently encountered chemical engineering operations. Drying generally signifies the removal of liquid from a solid by evaporation, although gases are also dried.

Industrial dryers are used for removing moisture from substances, products or materials in a business or manufacturing capacity. The term "industrial dryer" is a general reference that applies to dryers no matter what their particular method of drying is: air, infrared or spray drying. Because of the variety, there is no single design or model of industrial dryer, though there are some shared characteristics.

Many dryers are made from stainless steel because it is strong, sanitary and corrosion resistant. They are often cylindrical tanks or rectangular boxes with multiple intake and output valves, connections, openings, gauges and controls. Some may be continuous-able to dry a constant flow of materials and utilize a conveyor belt while others work in batches. The capacity depends on the kind of dryer and the material that will be dried. Certain dryers can dry over 25,000 pounds an hour while others can be built to hold only one cubic foot. Dryers are essential for the pharmaceutical, food processing, manufacturing, agricultural, pollution control, water treatment and paper industries and have multiple functions when working with chemicals, dairy products, fertilizers, grains, minerals, paper, plastics, refuse and more.

Most industrial dryers are bolted or welded together, depending on the importance of the seams, the anticipated product and any motion the dryer will endure. The three main methods of drying encompass a variety of models that carry out the task in different ways.

Air dryers are the most common industrial dryers. They bring materials into direct contact with hot air which causes moisture to evaporate and diffuse into the air, leaving behind a dry product.

Flash dryers, freeze dryers, fluid bed dryersand rotary dryers all fit in this category though their designs vary. Flash dryers use a short intense burst of heat to dry materials almost instantly while freeze drying uses cold air and vacuums to freeze moisture and sublime it away.

Fluid bed dryers shoot steam up through a perforated plate in order to cause the solid material to behave like a fluid; rotary dryers are large drums that dry products as they turn and tumble the material through the hot air contained inside.

Infrared dryers rely on electromagnetic radiation from a certain segment of the wavelength to dry solid materials quickly and without overheating them because the wavelength can be matched to the absorption rate of the product to maximize energy and resources.

Spray drying introduces the material to jets of hot steam which causes the moisture to flash dry and evaporate. Spray drying is highly suited for the continuous production of dry solids in either powder, granulate or agglomerate form from liquid feedstocks as solutions, emulsions and pumpable suspensions. Therefore, spray drying is an ideal process where the end-product must comply to precise quality standards regarding particle size distribution, residual moisture content, bulk density, and particle shape.

4. Answer the questions to the text:

1. What does drying signify?

2. What are main methods of drying?

3. What shared characteristics do industrial dryers have?

4. What are dryers essential for?

5. What is the principle of action of air dryers?

6. What do flash dryers use to dry materials?

7. What dryers rely on electromagnetic radiation from a certain segment of the wavelength?

8. What is spray drying highly suited for?

5. Complete the word combinations according to the context and translate them into Ukrainian:

	Ukrainian translation
1. particular method of __________
2. intake and output __________
3. water treatment and paper _________
4. direct contact with hot __________
5. a short intense burst of heat _________
6. steam up through a perforated plate__________
7. to dry solid materials quickly and without __________
8. to flash dry and __________

6. Match the words from the text with their synonyms on the right:

1) moisture	a) production	1)
2) method	b) flood	2)
3) characteristic	c) movement	3)
4) utilize	d) expected	4)
5) manufacturing	e) vapor	5)
6) anticipated	f) feature	6)
7) motion	g) make	7)
8) cause	h) humidity	8)
9) flow	i) use	9)
10) steam	j) way	10)

7. Point out the sentences containing information directly from the text:

1. Because of the variety, there is no single design or model of industrial dryer, though there are some shared characteristics.

2. Fluidized spray dryers are operationally flexible and enable production of a wide range of physical properties and optimum thermal efficiency because of the drying at the low temperature.

3. Flash dryers are extensively used for drying powders and granules, crystalline material.

4. Many dryers are made from stainless steel because it is strong, sanitary and corrosion resistant.

5. All spray dryers use some type of atomizer or spray nozzle to disperse the liquid or slurry into a controlled drop size spray.

6. The three main methods of drying encompass a variety of models that carry out the task in different ways.

7. In chemical synthesis, products are often freeze-dried to make them more stable, or easier to dissolve in water for subsequent use.

8. Spray drying introduces the material to jets of hot steam which causes the moisture to flash dry and evaporate.

9. Air heating increases the driving force for heat transfer and accelerates drying.

10. Every spray dryer consists of feed pump, atomizer, air heater, air disperser, drying chamber, and systems for exhaust air cleaning and powder recovery.

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