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Text 2. Thermal power station
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Unit 1
Memorize the words
to convert – превращать, преобразовать;
condensate – конденсат, конденсировать, превращать пар в воду, сгущать, сжимать;
vapour prime mover – паровой двигатель, паровая турбина;
furnace – топка, печь, корпус (многокорпусного котлоагрегата), котел центрального парового отопления.
boiler – котел, котельный агрегат, парогенератор, бойлер, подогреватель;
heater – подогреватель; калорифер;
heat exchanger – теплообменник;
drum – барабан, цилиндр;
boiling tube – кипятильные трубы котла;
coil – обмотка, катушка;
pump – насос, помпа; качать, накачивать, откачивать;
dust collector – коллектор пылеуловитель, пылевая камера, пылесборник;
duct –труба; трубопровод; канал, проход; туннель; короб, проходить, течь по каналу или трубе;
storage – запас, накопление, сборник, емкость;
pulverizer – распылитель, мельница для тонкого разлома;
feeder – питатель; подающий механизм, фидер;
fun – вентилятор;
suspension – взвесь; взвешенное состояние;
burner – горелка, форсунка;
hotwell – сборник конденсата; сборник горячей воды;
psi (pound per square inch) – фунтов на квадратный дюйм.
Text 1. The steam power plant
Do the following tasks:
1) Match English words and word combination with their Russian equivalents.
To convert, to discharge, prime mover, condenser, to generate, furnace, super heater, economizer, drum, to evaporate, feed water, chimney, pump, boiler, heat exchanger, combustion, dust collector, induced draft fan, forced-draft fan, pulverizer.
Конденсатор, газоохладитель; превращать; вырабатывать; разгружать, выпускать, выбрасывать; первичный двигатель, источник энергии; печь; цилиндр; пароперегреватель; питательная вода; подогреватель; испарять; дымовая труба, дымоход; теплообменник; искусственная вентиляция; насос; сгорание, воспламенение, возгорание; котел; пылевая камера, пылесборник; принудительная вентиляция; распылитель, мельница для тонкого размола.
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2) Make up 10 questions about the text and let your neighbour answer them, then change parts.
3) Retell each part of the text separately.
4) Give a written translation of the text into Russian.
The steam power plant
The function of a steam power plant is to convert the energy in nuclear reactions or in coal, oil or gas into mechanical or electric energy through the expansion of steam from a high pressure to a low pressure in a suitable prime mover such as a turbine or engine. A non-condensing plant discharges the steam from the prime mover at an exhaust pressure equal to or greater than atmospheric pressure.
In general, central-station plants are condensing plants since their sole outputs is electric energy and a reduction in the exhaust pressure at the prime mover decrease the amount of steam required to produce a given quantity of electric energy. Industrial plants are frequently non-condensing plants because large quantities of low pressure steam are required for manufacturing operations. The power required for operation of a manufacturing plant may often be obtained as a by-product by generating steam at high pressure and expanding this steam in a prime mover to the back pressure at which the steam is needed for manufacturing processes.
The steam generating unit consists of a furnace in which the fuel is burnt, a boiler, super heater, and economizer, in which high pressure steam is generated, and an air heater in which the loss of the energy due to combustion of the fuel is reduced to a minimum. The boiler is composed of a drum, in which a water level is maintained at about the mid-point so as to permit water to circulate from the drum through the tubes and back to the drum. The hot products of combustions from the furnace flow across the boiler tubes and evaporate part of the water in the tubes. The furnace walls are composed of tubes which are also connected to the boiler drum to form very effective steam-generating surfaces. The steam which is separated from the water in the boiler drum then flows through a super heater which is in effect a coil of tubing surrounded by the hot products of combustion. The temperature of the steam is increased in the super heater to perhaps 800° to 1100° F, at which temperature the high-pressure superheated steam flows through suitable piping to the turbine.
Since the gaseous products of combustion leaving the boiler tube bank are at a relatively high temperature and their discharge to the chimney would result in a large loss in energy, an economizer may be used to recover part of the energy in these gases. The economizer is a bank of tubes through which the boiler feed water is pumped on its way to the boiler drum.
A reduction in gas temperature may be made by passing the products of combustion through an air heater which is a heat exchanger cooled by the air required for combustion. This air is supplied to the air heater at normal room temperature and may leave the air heater at 400° to 600° F, thus returning to the furnace energy that would otherwise be wasted up the chimney. The products of combustion are usually cooled in an air heater to an exit temperature of 275° to 400° F, after which they may be passed through a dust collector which will remove objectionable dust and hence through an induced-draft fan to the chimney. The function of the induced-draft fan is to pull the gases through the heat-transfer surfaces of the boiler, super heater, economizer and air heater and to maintain a pressure in the furnace that is slightly less that atmospheric pressure. A forced-draft fan forces the combustion air to flow through the air heater, duct work, and burner into the furnace.
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Coal is delivered to the plant in railroad cars or barges which are unloaded by machinery. The coal may be placed in storage or may be crushed and elevated to the overhead raw-coal bunker in the boiler room.
The coal flows by gravity from the overhead bunker to the pulverizer or mill through a feeder which automatically maintains the correct amount of coal in the mill. In the mill the coal is ground to a fine dust. Some of the hot air from the air heater is forced through the mill to dry the coal and to pick up the finely pulverized particles and carry them in suspension to the burner where they are mixed with the air required for their combustion and discharged into the furnace at high velocity to promote good combustion.
The high-pressure, high-temperature steam is expanded in a steam turbine which is generally connected to an electric generator. From 3 to 5 percent of the output of the generator is needed to light the plant and to operate many motors required for fans, pumps, etc., in the plant. the rest of the generator output is available for distribution outside the plant.
The condensed steam, which is normally at a temperature of 70° to 100° F, is pumped out of the condenser by means of a hot-well pump and is discharged through several feed-water heaters to a boiler feed pumps that delivers the water to the economizer.
Most steam power plants of large size are now being built for operation at steam pressures of 1500 to 2400 psi, and in some plants pressures up to 5000 psi are being used. Steam temperatures of 1000° to 1100° F are in general use. Turbine generator capacities of 250,000 kw (1kilowatt =1.34 horsepower) are common, and units of 500,000 kw are in operation. Steam-generating units capable of delivering 3,000.000 1b of steam per hr are now in operation. Overall efficiency of the plant from raw coal supplied to electric energy delivered to the transmission line depends upon size, steam pressure, temperature, and other factors, and 40 percent is now being realized on the basis of a full year of operation.
Text 2. Thermal power station
Do the following tasks:
1) Make up a list of new terms you can find in the text. Translate them into Russian.
2) Read the text. Translate it into Russian.
3) Make up a detailed plan of each part of the text:
a) divide the text into several parts;
b) give each part a heading. Retell each part of the text separately.
4) Write an abstract to the text before doing the writing task read this to help you.
There are two types of abstracts informational and descriptive.
Informational abstracts:
- communicate contents of reports
- include purpose, methods, scope, results, conclusions and recommendations.
- highlight essential points.
- are short – from a paragraph to a page or two, depending upon the length of the report (10% or less of the report)
- allow readers to decide whether they want to read the report.
Descriptive abstracts:
- tell what the report contains
- include purpose, methods, scope, but not results, conclusions and recommendations
- are always very short – usually under 100 words.
- Introduce subject to readers, who must then read the report to learn study results.
Thermal power station
A thermal power station is a power plant in which the prime mover is steam driven. Water is heated, turns into steam and spins a steam turbine which drives an electrical generator. After it passes through the turbine, the steam is condensed in a condenser and recycled to where it was heated; this is known as a Rankine cycle. The greatest variation in the design of thermal power stations is due to the different fossil fuel resources generally used to heat the water. Some prefer to use the term energy center because such facilities convert forms of heat energy into electrical energy. Certain thermal power plants also are designed to produce heat energy for industrial purposes of district heating, or desalination of water, in addition to generating electrical power. Globally, fossil fueled thermal power plants produce a large part of man-made CO2 emissions to the atmosphere, and efforts to reduce these are varied and widespread.
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Almost all coal, nuclear, geothermal, solar thermal electric, and waste incineration plants, as well as many natural gas power plants are thermal. Natural gas is frequently combusted in gas turbines as well as boilers. The waste heat from a gas turbine can be used to raise steam, in a combined cycle plant that improves overall efficiency. Power plants burning coal, fuel oil, or natural gas are often called fossil-fuel power plants. Some biomass-fueled thermal power plants have appeared also. Non-nuclear thermal power plants, particularly fossil-fueled plants, which do not use co-generation are sometimes referred to as conventional power plants.
Commercial electric utility power stations are usually constructed on a large scale and designed for continuous operation. Electric power plants typically use three-phase electrical generators to produce alternating current (AC) electric power at a frequency of 50 Hz or 60 Hz. Large companies or institutions may have their own power plants to supply heating or electricity to their facilities, especially if steam is created anyway for other purposes. Steam-driven power plants have been used in various large ships, but are now usually used in large naval ships. Shipboard power plants usually directly couple the turbine to the ship's propellers through gearboxes. Power plants in such ships also provide steam to smaller turbines driving electric generators to supply electricity. Shipboard steam power plants can be either fossil fuel or nuclear. Nuclear marine propulsion is, with few exceptions, used only in naval vessels. There have been perhaps about a dozen turbo-electric ships in which a steam-driven turbine drives an electric generator which powers an electric motor for propulsion.
Combined heat and power plants (CH&P plants), often called co-generation plants, produce both electric power and heat for process heat or space heating. Steam and hot water lose energy when piped over substantial distance, so carrying heat energy by steam or hot water is often only worthwhile within a local area, such as a ship, industrial plant, or district heating of nearby buildings.
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