Concentration and crystallization machines.

After purification, the juice, now called clear or thin juice, is pumped to multiple-effect evaporators similar to those used in raw cane sugar manufacture. In the evaporators the juice is concentrated to thick juice (60-65 percent dissolved solids), which is mixed with remelted lower grades of sugar to form

standard liquor. From this standard liquor, sugar is crystallized, usually in three stages. In all boiling systems, sugar obtained from the first stage is processed as a final product, while sugar from the second and third stages is remelted and recycled into another batch of thick juice.

Sugar is separated from mother liquor in basket centrifuges, and it is dried in either rotary louvred driers or fluidized-bed dryer-coolers.

Exercise 2. Answer the following questions.

1. Is equipment for beet sugar manufacture similar to that for cane sugar production? Explain your opinion.

2. What machines are used for beet washing?

3. What cutting machines are usually employed?

4. Where does sugar diffusion take place?

5. Why are temperatures above 700 C maintained in diffusers?

6. What stages does a modern purification system involve? 7. What is the purpose of an evaporator?

8. What machines are used for sugar separation?

9. What is sugar output at modern processing plants?

10. What sugar processing machine is a major energy consumer?

Exercise 3. Complete the scheme of the essential stages in white sugar manufacture.

beet from harvest

pulp pressing

pulp drying

Exercise 4. Translate the following word-combinations.

To be off-loaded at the factory, mud recirculation, cold main liming, to be washed in a flume to remove rocks and dirt, remaining beet pulp, a rotary louvred drier, raw cane sugar manufacture, remelted lower grades of sugar, in order to offer maximum surface area for extraction, a beet pulp drier.

Exercise 5. Complete each sentence with a word or phrase from the box.

multicell countercurrent diffuser multistage purification system slicing machine

basket centrifuge multiple-effect evaporators

1. The beet roots are cut into V-shaped strips by means of a ___. 2. A ___ is a device where sugar extraction takes place.

3. A ___ involves cold pre-liming followed by cold main liming, hot main liming, first carbonatation, filtration and mud recirculation, addition of heat and soda, second carbonatation, and filtration.

4. In the ___ the sugar beet juice is concentrated to thick juice. 5. The ___ is a machine for separating sugar from mother liquor.

Exercise 6. Make pairs of synonyms from the upper and lower lists.

a) syrup, thin juice, rotary, raw, to dry, melasse, imbibition, to off-load;

b) maceration, to discharge, revolving, blackstrap, clear juice, unprocessed, thick juice, to dehydrate.

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Exercise 7. Complete the table concerning the stages of beet sugar production using the information from the texts above and your own knowledge.

Process Purpose Equipment 1. Washing

2. Cutting

3. Juice extraction 4. Purification

5. Concentration 6. Crystallization 7. Separation

8. Drying

Compare processes of sugar manufacture from sugarcane and beet. What are their similarities and differences?

Exercise 8. Try the crossword and give the explanation of the hidden word.

1 1. A machine for sugar concentration

2 2. A device for cane crushing

3 3. A machine for breaking cane into shreds

4 4. Another word for "scraper"

5 5. A machine for sugar extraction

6 6. No 5 does much harm to the …

7 7. Water of imbibition or …

8 8. A drum machine where fruit is disintegrated

9 9. A device for fruit stalks removing

10 10. A dehydration machine

11 11. Beet roots are cut into …

12 12. A machine for separation crystals and liquor

Exercise 9. Word building.

What are the meanings of the prefixes in the box? Fill in the gaps with a correct prefix. mini micro mono inter multi deci semi self

1. The number system we use in everyday life is the ___mal system which has a base of 10.

2. In the middle of the 19th century certain characteristics of ___conductors began to be utilized for

commercial refrigeration.

3. The control process at the plant may be fulfilled by one ___computer. 4. Its screen may be ___chromatic or it may produce ___colour images.

5. Modern sugar purification systems are usually ___stage.

6. Temperatures about 1000 C destroy all ___organisms in products.

7. Operation principles of big meat processing plants do not differ from those of ___plants. 8. Single units in the processing lines may be ___linked via pipes or conveyors.

9. Modern smokehouse cabinets may be ___-cleaned.

10. Diffusion is not the ___action between substances, it is a process of mixing the substances.

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UNIT 5

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