Translate into English

1. Качество топлива определяется его элементарным составом, теплотой сгорания, вязкостью, удельным весом, температурой вспышки, температурой воспламенения и застывания, а также некоторыми другими характеристиками.

2. Топливо состоит из следующих химических элементов – углерода, водорода, кислорода, азота и частично серы.

3. Теплота сгорания топлива – это тепловая энергия, высвобождаемая во время сгорания.

4. Различают две теплоты сгорания: высшую и низшую.

5. Вязкость – это сопротивление при течении жидкости.

6. Вязкость определяют с помощью вискозиметров.

7. Тяжелое топливо обычно характеризуется высокой вязкостью.

8. Удельный вес - это соотношение веса определенных равных объемов топлива и воды.

9. При температуре воспламенения топливо начинает гореть.

10. Температура застывания – это самая низкая температура, при которой топливо можно перекачивать.

11. Следует также принимать во внимание следующие характеристики топлива: содержание золы, серы, влаги, содержание механических примесей, общую кислотность и некоторые другие характеристики.

TEXT B

Fuel oils characteristics

Fuel oils have various characteristics which determine their performance and are quoted in specifications.

The specific gravity is the weight of a given volume of fuel compared to the weight of the same volume of water expressed as a ratio, and measured at a fixed temperature.

Viscosity is a resistance to flow. A highly viscous fuel will therefore require heating in order to make it flow. Measurement of viscosity is by Redwood, Saybolt seconds for a given volume of fuel.

The ignition quality of a fuel is measured by the time delay between injection and combustion, which should be short for good controlled burning.

The flash point is the temperature at which the fuel is ignited with a small open flame.

The pour point is slightly above the temperature at which the fuel just flows under its own weight. It is the lowest temperature at which the fuel can be easily handled.

Sulphur content is of importance since it is considered a cause of engine wear. A maximum limitis usually included in specifications.

The calorific value of a fuel is the heat energy released during combustion. Two values are used, the more common being the Higher Calorific Value, which is the heat energy resulting from combustion. The Lower Calorific Value is a measure of the heat energy available and does not include the heat energy contained in steam produced during combustion but passing away as exhaust. The measurement is obtained from a calorimeter test where a small fuel quantity is burnt under controlled conditions.

E X E R C I S E S

1. hydrometer; calorific value; pour point; flash point; heavy; specific gravity

1. The specific gravity is obtained by means of a …

2. … is the lowest temperature at which the fuel can be easily handled.

3. … oils usually have high viscosity.

Deposits; viscosity; calorimeter; hydrometer; fuel; automatically; steam.

1. In Europe to measure … they use either Redwood or Saybolt seconds.

2. The practical method of determining the B.t.u. equivalent of oil fuel is by means of a ….

1. 2. … is a relation between the weights of a definite volume of oil and water.

TEXT C

Пивненко стрю47 -9

UNIT 5

TEXT A

FEED WATER

Feed water is the water supplied to a boiler to generate steam or hot water. It is delivered to the boiler by the feed pump. As the water is evaporated, the impurities in it remain in the boiler in the form of the salt deposits.

Water containing impurities may lead to the following problems in boilers: scale, foaming, priming and corrosion.

The chief salts forming scale are those of calcium and magnesium. Magnesium sulphate is a salt commonly found in boiler water and it forms a soft, sludgy mass, not very harmful, which can be removed by blowing down. Calcium sulphate produces a hard scale.

Alkalis or phosphate are sometimes put into marine boilers to prevent scale.

Foaming may be the result of dirty water, certain types of organic matter, oils in solution, the presence of excess alkalinity. Oil is very injurious to a boiler: it adheres to the tube surfaces and causes overheating and rupture of tubes.

Priming may be due to improper construction of boiler or extremely high ratings. The most common measure to prevent foaming and priming is to maintain the water at the lowest level. Avoiding high water levels, excessive boiler loads, and sudden load changes also helps. If foaming and priming occur, the blow off is opened several times, and fresh water added.

The main cause of boiler corrosion results from the dissolved gases, oxygen and carbon dioxide, found in feed water. They will react with the metals in the boiler system and lead to boiler corrosion. In order to protect the boiler from these contaminants, they should be controlled or removed, usually by use of a deaerator.

Acids due to oils in solution may be neutralized by the addition of sodium carbonate.

For efficient boiler operation a chemical analysis of the feed water must be run at least once a day.

Vocabulary

feed water питательная вода

evaporate, v испаряться

impurity, n примесь; загрязнение

remain, v оставаться

salt deposits отложения солей

scale накипь

foaming вспенивание

priming вскипание

soft sludge мягкий шлак; шлам

brittle scale хрупкая, ломкая накипь

harmful, adj вредный

blowing down нижнее продувание

alkali, n щелочь

organic matter органическое вещество

solution, n раствор

excess alkalinity избыточная щелочность

injurious, adj вредный

adhere, v прилипать; приставать

rupture, n разрыв

rating, n мощность

load, n нагрузка

blow off верхнее продувание

fresh water свежая; пресная вода

dissolve, v растворять

contaminant, n загрязняющее вещество; примесь

deaerator, n деаэратор

acid, n кислота

sodium chloride хлорид натрия

E X E R C I S E S

1. Give English equivalents:

Питательная вода; подавать; питательный насос; содержать примеси; приводить к проблемам; коррозия; образовывать; кальций; магний; сульфат магния; мягкая масса; предотвращать образование накипи; наличие; вызывать перегрев; мера; избегать; чрезмерные нагрузки; углекислый газ; карбонат натрия, проводить химический анализ.

2.Change these sentences using the modal verbs may, can, must:

1. Foaming is due to the presence of dirty water in the boiler.

2. Oil in the feed water is very injurious to the boiler.

3. Priming is also due to a poorly designed steam drum.

4. Acids are neutralized by the addition of sodium carbonate.

5. A little of the chemicals is added at a time.

3. Change these sentences into the passive:

1. The addition of alkalis prevents scale formation.

2. The presence of oils in solution causes foaming.

3. Some of the salts produce a soft sludge.

4. The chlorides of sodium and magnesium and the sulphate of iron cause corrosion.

5. We may neutralize acids by the addition of sodium carbonate.

4. Supply prepositions:

1. Feed water is the water supplied … a boiler … the feed pump.

2. The impurities … the boiler remain … the form of the salt deposits.

3. Alkalis or phosphate are put … marine boilers to prevent scale.

4. Oil is very injurious … a boiler as it adheres … the tube surfaces.

5. Priming may be due … improper construction of boiler.

6. To prevent priming it is necessary to maintain the water … the lowest level.

7. Corrosion results … the dissolved gases found … feed water.

8. Acids may be neutralized … the addition of sodium carbonate.

5. Answer the questions:

1. What is feed water?

2. By what device is the feed water supplied to the boiler?

3. What substances remain in the boiler as the water is evaporated?

4. What problems may water containing impurities lead to?

5. How can a soft sludge be removed?

6. What salt produces a hard scale?

7. What may foaming be the result of?

8. What priming may be due to?

9. What gases cause corrosion?

10. How often must a chemical analysis of the feed water be run?

6. Translate into English:

1. Питательная вода подается в котел насосом.

2. Примеси воды остаются в котле в виде отложений.

3. Мягкий шлак может быть удален из котла продуванием.

4. Некоторые соли образуют твердую накипь.

5. Для предотвращения накипи в котле используются щелочи и фосфаты.

6. Содержание в воде органических веществ может привести к вспениванию.

7. В случае вскипания применяется продувание и добавляется свежая вода.

8. Растворенные в питательной воде кислород и углекислота вызывают коррозию стенок котлов.

9. Химический анализ питательной воды должен производиться на судне не реже одного раза в день.

TEXT B

Purity of boiler feed water

Modern boilers require very pure feed water. The water required for boiler feed purposes, i.e. for steam generation should be of very high quality and thus requires a lot of treatment. Untreated water, containing impurities may lead to the following problems in boilers.

Most pure water will contain some dissolved salts. These salts then adhere to the heating surfaces as a scale and reduce heat transfer, which can result in local overheating and failure of the tubes. Other salts remain in solution and may produce acids which will attack the metal of the boiler. An excess of alkaline salts in a boiler will cause cracking of the metal which may lead to serious failure.

The presence of dissolved oxygen and carbon dioxide in boiler feed water can cause considerable corrosion of the boiler and feed systems. When boiler water is contaminated by suspended matter, an excess of salts or oil, foaming may occur. This is foam which collects on the water surface in the boiler drum. Foaming leads to priming which is the carry-over of water with the steam leaving the boiler drum. Any water present in the steam entering a turbine will do considerable damage.

Various amounts of different metal salts can be found in water. These include the chlorides, sulphates and carbonates of calcium, magnesium. These dissolved salts in water make up the 'hardness' of the water. Calcium and magnesium salts are the main causes of hardness.

TEXT C

CONTAMINATION OF FEED water

The quality of boiler water plays an important role in boiler operation. Contamination of boiler water leads to several types of problems, including the main ones – corrosion and scale formation.

Inside the boiler system, the boiler feed water passes through a series of tubes and equipment. The feed water is always chemically treated to reduce the effects of harmful minerals and gases.

The main problem starts when a lot of this boiler feed water is lost through leakages and processes such as boiler blow down, soot blowing etc., and make-up water is added to compensate this loss. This make-up water brings in a lot of the impurities into the boiler system.

How is the make-up feed water contaminated?

Boiler feed water is mainly taken from the fresh water generator. The sea water contains a large amount of salts and other dissolved minerals and gases. Many of them are harmful and eventually lead to boiler problems.

Saltdeposits act as insulators and lower the heat transfer rate.

The insulating effect of deposits also causes the boiler metal temperature to rise and lead to tube-failure by overheating.

Large amounts of such deposits throughout the boiler can reduce the heat transfer and decrease the overall boiler efficiency.

UNIT 6

TEXT A

BOILER PARTS. THE FURNACE

A furnace provides steady burning of fuel.

The furnaces of marine water-tube boilers are lined with refractory firebrick backed up by the insulating bricks. This brickwork acts as furnace insulation and also, by maintaining a high furnace wall temperature, assists combustion.

Water walls are used in water-tube boilers to contain the heat of the furnace and reduce the amount of refractory material required. Water walls consist of a number of tubes and extend along the sides of the furnace setting.

To provide the efficient combustion process of burning oil fuel, a certain set of conditions is necessary: maintenance of high furnace temperature, provision of continuous oil fuel and air supply and removing products of combustion.

The oil is first heated in steam or electric fuel oil heaters. This reduces its viscosity and makes it easier to pump, filter, and finally to atomize. The heated oil passes through the burners where it is atomized; this process breaks it up into a fine spray of droplets presenting a very large surface area of oil to the combustion processes.

Different types of burners have been designed for burning liquid fuel. Mechanical oil burners and steam-assisted ones are employed to obtain efficient atomization. Mechanical atomizing oil burners may be classified according to their method of atomization as centrifugal atomizers and rotary cup atomizers.

Steam-assisted oil burners are widely spread in marine practice. Their advantages are high quality atomization and a wide range of fuel oil feed control.

Vocabulary

steady, adj устойчивый

firebrick, n огнеупорный кирпич

brickwork, n кирпичная кладка

insulation, n изоляция

assist, v помогать; способствовать

water wall экран из водогрейных трубок

amount, n количество

setting, n кладка; обмуровка

set of conditions комплекс условий

maintenance, n поддержание

atomize, v распылять; тонко измельчать

to break up разбивать(ся)

droplet, n капля

surface, n поверхность

mechanical oil burner механическая форсунка

steam-assisted oil burner паромеханическая форсунка

centrifugal atomizer центробежный распылитель

rotary cup atomizer форсунка с вращающимся распылителем

range, n диапазон

oil feed подача топлива

E X E R C I S E S

1. Give English equivalents:

Обеспечивать; горение топлива; облицовывать (футеровать); выступать в качестве; горение; тянуться; поддерживать; высокая топочная температура; непрерывная подача; продукты сгорания; топливоподогреватель; уменьшать вязкость; проходить; мелкораспыленная струя; по методу распыления; преимущество; регулирование.

2. Supply prepositions:

1. Water-tube boilers are lined … refractory firebrick.

2. The brickwork acts … furnace insulation.

3. Water walls consist … a number of tubes and extend … the sides of the furnace setting.

4. The oil is first heated … steam or electric fuel oil heaters.

5. The heated oil passes … the burners where it is atomized.

6. Mechanical atomizing oil burners may be classified … … their method of atomization.

7. Steam-assisted oil burners are widely spread … marine practice.