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Text 4. Industrial Gas Turbines



Gas turbines are widely used in industry for electrical power production. Industrial gas turbines range in size from truck-mounted mobile plants to enormous complex systems. They can be particularly efficient up to 60%, when waste heat from the gas turbines is recovered by a heat recovery steam generator to power a conventional steam turbine in a combined cycle configuration. They can also be used for space or water heating, cooling or refrigeration. The power turbines in the largest industrial gas turbines operate at 3,000 or 3,600 rpm to match the AC power grid frequency and to avoid the need for a reduction gearbox. Such engines require a dedicated enclosure. Simple cycle gas turbines in the power industry require smaller capital investment than either coal or nuclear power plants and can generate small or large amounts of power. Also, the actual construction process can take as little as several weeks to a few months, compared to years for base load power plants. Their other main advantage is the ability to be turned on and off within minutes, supplying power during peak demand. Since they are less efficient than combined cycle plants, they are usually used as peaking power plants, which operate anywhere from several hours per day to a couple dozen hours per year, depending on the electricity demand and the generating capacity of the region. In areas with a shortage of base load and load following power plant capacity a gas turbine power plant may regularly operate during most hours of the day and even into the evening. A typical large simple cycle gas turbine may produce 100 to 300 megawatts of power and have 35-40% thermal efficiency. The most efficient turbines have reached 46% efficiency.

Turboshaft engines are often used to drive compression trains (for example in gas pumping stations or natural gas liquefaction plants) and are used to power almost all modern helicopters.

Gas turbine engines have some essential advantages:

- very high power-to-weight ratio, compared to reciprocating engines (i.e. most road vehicle engines);

- smaller than most reciprocating engines of the same power rating;

- moves in one direction only, with far less vibration than a reciprocating engine, so very reliable;

- simpler design;

- low operating pressures;

- high operation speeds;

- low lubricating oil cost and consumption.

Gas turbine engines also have some disadvantages:

- cost is much greater than for a similar-sized reciprocating engine (very high-performance, strong, heat-resistant materials needed);

- use more fuel when compared to reciprocating engines and not so good unless in continual operation.

These disadvantages explain why road vehicles, which are smaller, cheaper and follow a less regular pattern of use than tanks, helicopters, large boats and so on, do not use gas turbine engines regardless of the size and power advantages.

 

Exercise 26. Translate the following universal words. Mind the difference in pronunciation and meanings in English and Ukrainian.

Mechanically, extract, atmospheric, form, combination, cycle, temperature, limit, factor, material, system, complex, maximum, micro, critical, optimize, ventilation, hydraulic, megawatt, configuration, mobile, refrigeration, reduction, investment, construction, process, base, minute, peak, region, typical, modern, prototype, stress, aerodynamic, optimal, radial, tank, optimal, integrity.

 

Exercise 27. Determine the parts of speech of the following words. Explain their grammar forms, name the affixes, if any, and translate.

Smaller, cheaper, less, regardless, single-stage, recuperator, expansion, atmospheric, pressure, thermodynamically, higher, withstand, might, hydraudynamic, oil-cooled, successfully, largely, largest, enormous, conventional, enclosure, several, anywhere, turboshaft, shortage, most, efficient, almost, all, both, well, thinner, power-to-weight, same, far, simpler, high-performance, heat-resistant, similar-sized, unless, gearbox, upstream, downstream, start-up, continual.

 

Exercise 28. Match the English terms in the left column with their Ukrainian equivalents in the right column.

 

1) ball bearing 2) piston 3) ducted fan 4) gearbox 5) turbojets 6) combustion chamber 7) heat exchanger 8) housing 9) journal bearing 10) thrust bearing a) редуктор b) корпус c) упорний підшипник d) поршень e) тяговий вентилятор f) радіальний підшипник g) камера згорання h) кульковий підшипник i) теплообмінник j) турбореактивні двигуни

 

Exercise 29. Translate the following attributive word combinations.

1) n + n:

single-stage compressor, gas turbines, fuel oil, air compressor, downstream turbine, combustion chamber, turbine blade, shaft power, heat engine, combustion temperature, heat exchanger, piston engine, rotor assembly, fuel system, thrust bearing, rotation rate, oil bearing, ball bearing, foil bearing, power plant, reduction gearbox, turboshaft engine, can combustion system, pressure ratio, diffuser exit, rotor suspension, power demand, power grid, rotor support, generator speed requirements.

 

 

2) V-ing + n:

resulting gases, supplying power, generating capacity, pumping station, running speed, leading efficiency, generating set, reciprocating engine, operating pressure, lubricating oil, moving part, limiting factor.

3) V-ed + n:

compressed air, wasted energy, combined cycle, combined heat, sophisticated turbine, cooled bearing, ducted fan, mounted plant, improved maintenance, produced gas, mixed air, ignited fuel, optimized parameters, connected fan, designed turbine, recovered energy, dedicated enclosure, advanced design, placed bearing, overhung suspension.

4) adj + n + n:

movable stator blades, hydrodynamic oil bearings, auxiliary power unit, single stage turbine, high pressure ratio, annular combustion chamber, dual fuel option, specific fuel consumption, industrial gas market.

 

Exercise 30. Complete the sentences, using Participles. Define the function of the Participles (an attribute; adverbial modifier, a part of a compound verbal predicate). Translate the sentences into Ukrainian.

1. A gas turbine extracts energy from a flow of hot gas (to produce) by combustion of gas or fuel oil in a stream of (to compress) air. 2. It has an upstream air compressor mechanically (to couple) to downstream turbine and a combustion chamber. 3. The (to result) gases are directed over the turbine blades, (to spin) the turbine and mechanically (to power) the compressor. 4. Finally, the gases are passed through a nozzle, (to generate) additional thrust. 5. Recuperators are heat exchangers that pass exhaust heat to the (to compress) air. 6. (To combine) cycle designs pass waste heat to steam turbine systems. 7. Simple turbines might have one (to move) part. 8. More (to sophisticate) turbines may have multiple shafts. 9. Jet engines are gas turbines (to optimize) to produce thrust from the exhaust gases or from (to duct) fans (to connect) to the gas turbines. 10. Industrial gas turbines range in size from truck–(to mount) mobile plants to enormous complex systems. 11. The power turbines in the largest industrial gas turbines require a (to dedicate) enclosure. 12. One of the main advantages of simple cycle gas turbines is the ability to be (to turn) on and off within minutes, (to supply) power during peak demand. 13. (To peak) power plants operate anywhere from several hours per day to a couple dozen hours per year, (to depend) on the electricity demand and the (to generate) capacity of the region. 14. Turboshaft engines are often (to use) in gas (to pump) stations.

 

Exercise 31. Match the synonyms and synonymous word combinations.

1) rate 2) recuperator 3) combustion chamber 4) radial 5) housing 6) waste gas 7) install 8) piston engine 9) usage 10) connect 11) continual a) casing b) internal combustion machine c) exhaust gas d) mount e) aplication f) speed g) continuous h) couple i) centrifugal j) heat exchanger k) combustor

 

Exercise 32. Match the beginnings (column A) and the ends of the sentences (column B).

A B
1. A gas turbine extracts energy from a flow of hot gas produced ... a) to produce thrust from the exhaust gases or from ducted fans.
2. Energy is released … b) that pass exhaust heat to the compressed air prior to combustion.
3. The limiting factor for heat engines is ability of steel, nickel, ceramic or other materials … c) for auxiliary power of larger machines, such as those inside an aircraft.
4. Recuperators are heat exchangers … d) which otherwise is wasted energy.
5. Most turbines also try to recover exhaust heat … e) to drive compression trains and to power almost all modern helicopters.
6. Jet engines are gas turbines optimized … f) to match the AC power grid frequency and to avoid the need for a reduction gearbox.  
7. Auxiliary power units are small gas turbines designed … g) reducing the turbine speed.
8. Turboshaft engines are often used … h) by combustion of gas or fuel oil in a stream of compressed air.
9. The power turbines in the largest industrial gas turbines operate … i) when compressed air is mixed with fuel and ignited in the combustor.
10. A flexible coupling connects the turbine to the two stage gearbox, … j) that make the engine to withstand heat and pressure.

 

Exercise 33. Translate the following terminological word combinations into Ukrainian.

a) Combustion of gas or fuel oil; upstream air compressor; downstream turbine; hot exhaust gas; all-cyclic heat engine; higher combustion temperature; greater efficiency; internal combustion piston engine; alternative rotor assembly; movable stator blades; complex piping; combined heat and power; rotation rate; turbine blade tip speed; hydrodynamic oil bearing; oil-cooled ball bearing; direct impulse; start-up power; power generation gas turbine; truck-mounted mobile plant; combined cycle configuration; AC power grid frequency; base load power plant; peaking power plant; single stage radial turbine; thinner blade tip region; inlet of the guide vanes; exhaust at diffuser exit; optimal running speed; thermal expansion; rotor support housing; overhung rotor suspension; two-stage gearbox; complete gas turbine generating set; low operating pressure;

b) to withstand heat and pressure; to maintain tip speed; to recover exhaust heat; to use waste heat; to determine the maximum pressure; to produce thrust; to generate thrust; to be designed for auxiliary power; to supply air for ventilation; to range in size; to be recovered by a heat recovery steam generator; to power a steam turbine; to be used for space or water heating; to avoid the need for a reduction gearbox; to be turned on and off within minutes; to be used as a peaking power plant; to depend on the electricity demand and the generating capacity; to drive compression trains; to be placed in the front of the rotor support housing; to avoid oil supply; to reduce the turbine speed.

 

Exercise 34. Complete the sentences giving English equivalents of the words in brackets and translate them.

1. Most turbines also try to recover (видiлене тепло) which is (марна витрата енергії). 2. Recuperators are (теплообмінники) that pass exhaust heat to the (стиснене повітря) prior to (згорання). 3. Mechanically gas turbines can be considerably less complex than (поршневий двигун внутрішнього згорання). 4. Jet engines are gas turbines optimized to produce thrust from the (вихлопний газ) or from (тяговий вентилятор) connected to the gas turbines. 5. Jet engines may have multiple (вали), hundreds of (лопатка турбіни), movable (лопатка статора) and a vast system of complex (трубопроводи), (камера згорання) and heat exchangers. 6. Traditionally (упорний підшипник) and (радіальний підшипник) have been hydrodynamic (масляний підшипник) or oil-cooled (кульковий підшипник). 7. (Допоміжні силові установки) are small gas turbines designed for (додаткова потужність) of larger machines. 8. Industrial gas turbines can be particularly efficient when (відпрацьоване тепло) from the gas turbine (регенерувати) by a (тепловий регенеруючий парогенератор) to power a conventional steam turbine in a combined cycle configuration. 9. The (силові турбіни) in the largest industrial gas turbines operate at 3,000 or 3,600 rpm to match the (електромережа змінного струму) frequency and to avoid the need for (редуктор). 10. (Турбовальні двигуни) are often used to drive (ряд розташованих послідовно один за одним компресорів) in (газонасосна станція) or (газозжижувальна установка).

 

Exercise 35. Translate the following sentences into English.

1. Газова турбіна – це механізм, який має одноступеневий відцентровий компресор, турбіну, рекуператор і пластинкові підшипники. 2. Газова турбіна вибирає енергію з потоку гарячого газу, створену у результаті згорання газу або палива у потоці стисненого повітря. 3. Енергія вивільняється, коли стиснене повітря змішується з паливом і займається у камері згорання. 4. Похідні гази направляються на лопатки турбіни, обертаючи турбіну і механічно живлячи компресор. 5. Нарешті гази проходять через сопло, виробляючи додаткову тягу, завдяки прискореному виштовхуванню гарячих вихлопних газів в атмосферний тиск. 6. Більшість турбін намагаються утилізувати видалене тепло, яке в іншому випадку є це марно витраченою енергією. 7. Рекуператори – це теплообмінники, які перепускають видалене тепло у стиснене повітря перед згоранням. 8. Механічні газові турбіни можуть бути значно простішими ніж поршневі двигуни внутрішнього згорання. 9. Прості турбіни можуть мати одну рухому частину: вал / компресор / турбіну / ротор, не враховуючи паливну систему. 10. Більш складні турбіни, як наприклад у сучасних реактивних двигунах, можуть мати декілька валів, сотні турбінних лопаток, рухомі лопатки статора, цілу систему складних трубопроводів, камеру згорання і теплообмінники. 11. Упорні і радіальні підшипники є важливою складовою частиною конструкції. 12. Реактивні двигуни використовуються для вироблення тяги від вихлопних газів або тягових вентиляторів, з’єднаних з газовою турбіною. 13. Допоміжні силові установки – це маленькі газові турбіни, які призначаються для вироблення додаткової потужності двигунів. 14. Промислові газові турбіни можуть бути особливо ефективними у випадку, коли відпрацьоване тепло від газової турбіни регенерується тепловим регенеруючим парогенератором для живлення звичайної парової турбіни у комбінованій циклічній системі. 15. Силові турбіни у найбільших промислових газових турбінах відповідають вимогам функціонування електромереж змінного струменя і не потребують використання редукторіві. 16. Прості за циклом вироблення енергії газові турбіни можуть виробляти малу або велику кількість енергії. 17. Однією з переваг цих газових турбін є те, що їх можна запускати або зупиняти за лічені хвилини, постачаючи енергію у період найбільшого попиту. 18. Турбовальні двигуни зазвичай використовуються для запуску ряду послідовно розташованих один за одним компресорів, наприклад, на газонасосних станціях або газозжижувальних заводах, а також для живлення майже усіх сучасних гелікоптерів.

 

Exercise 36. Say whether the given statements are true or false. If a statement is wrong, correct it. If true, enrich it with details.

1. Gas turbine engines are of very high power-to-weight ratio. 2. Reciprocating engines are smaller than gas turbine engines of the same power rating. 3. Gas turbine engines are of simpler design than reciprocating engines. 4. One of the main disadvantage of the gas turbine engine is its high operation speeds. 5. High operating pressure is the advantage of gas turbine engines. 6. Gas turbine engines need very high-performance, strong and heat-resistant materials, so they are high in cost. 7. Gas turbine engines disadvantage is that they use more fuel, as compared to reciprocating engines and they are not so good unless in continual operation.

 

Exercise 37. Work in pairs. Complete the following questions on texts 3, 4 and answer them.

… is a gas turbine?

… does a gas turbine have?

… is energy released?

… does a gas turbine operate?

… does higher combustion temperature mean greater efficiency?

… are combined cycle designs used for hot water production?

… is the difference in simple and more sophisticated designs?

… are jet engines optimized for?

… do jet engines produce thrust?

… are auxiliary power units designed for?

… can industrial gas turbines be efficient?

… can industrial gas turbines be used?

… are the advantages of simple cycle gas turbines?

… of industrial gas turbines is more efficient?

… are turboshaft engines used?

… are radial gas turbines applications?

… are the main distinctive features of radial gas turbines design?

… are the main advantages of gas turbine engines?

 

Exercise 38. Speak on:

1. Types of Turbines.

2. Turbines Operation and Purposes.

3. Gas Turbines Design and Operation.

4. Industrial Gas Turbines.

 

Exercise 39. Choose the right answers to the questions on texts 3 and 4.

1. What is a turbine used for?

a) for compression of gas;

b) for refinery of gas;

c) for extraction of energy from a fluid flow.

2. What turbines require a pressure casement?

a) impulse turbines;

b) reaction turbines;

c) wind turbines.

3. What types of turbines are used in power plants using coal, fuel oil or nuclear power?

a) water turbines;

b) wind turbines;

c) steam turbines.

4. What turbines are referred to internal combustion machines?

a) wind turbines;

b) water turbines;

c) gas turbines.

5. How are turbines with a shroud at rotor blade tips called?

a) shroudless turbines;

b) bladeless turbines;

c) shrouded turbines.

6. What influences the efficiency of all cyclic heat engines?

a) more complex construction;

b) higher combustion temperature;

c) larger size of engine.

7. What does rotor tip speed depend on?

a) combustion temperature;

b) engine design;

c) engine size.

8. What engines produce thrust primarily from the direct impulse of exhaust gases?

a) turbofans;

b) turboshaft engines;

c) turbojets.

9. What industrial gas turbines are used to supply power during peak demand?

a) combined cycle gas turbines;

b) simple cycle gas turbines;

c) large industrial gas turbines.

10. What are the disadvantages of gas turbine engines?

a) low operating pressure;

b) simple design;

c) high fuel consumption.







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