Full operating principle of thermal power plant. Thermal power plants (CHP, IES): varieties, types, operating principle, fuel

Combined heat and power plant

The simplest diagrams of combined heat and power plants with various turbines and various schemes vacation couple
a - turbine with back pressure and steam extraction, heat release - according to an open circuit;
b - condensing turbine with steam extraction, heat release - through open and closed schemes;
PC - steam boiler;
PP - steam superheater;
PT - steam turbine;
G - electric generator;
K - capacitor;
P - adjustable production selection steam for the technological needs of industry;
T - adjustable district heating extraction;
TP - heat consumer;
OT - heating load;
KN and PN - condensate and feed pumps;
PVD and HDPE - high- and low pressure;
D - deaerator;
PB - feed water tank;
SP - network heater;
CH - network pump.

Combined heat and power plant (CHP)- a thermal power plant that generates not only electrical energy, but also heat, supplied to consumers in the form of steam and hot water. The practical use of waste heat from engines rotating electric generators is distinctive feature Thermal power plant is called district heating. The combined production of two types of energy contributes to more economical use fuel compared to the separate generation of electricity at condensing power plants (in the USSR - state district power plants) and thermal energy at local boiler plants. Replacement of local boiler houses that waste fuel and pollute the atmosphere in cities and towns, centralized system Heat supply contributes not only to significant fuel savings, but also to increasing the cleanliness of the air basin and improving the sanitary condition of populated areas.

Description

The initial source of energy at thermal power plants is organic fuel (at steam turbine and gas turbine thermal power plants) or nuclear fuel (at nuclear thermal power plants). The predominant distribution are steam turbine thermal power plants using fossil fuels, which, along with condensing power plants, are the main type of thermal steam turbine power plants (TSPP). There are CHP plants industrial type- for supplying heat to industrial enterprises, and heating type- for heating residential and public buildings, as well as to supply them with hot water. Heat from industrial thermal power plants is transferred over a distance of up to several kilometers (mainly in the form of steam heat), from heating plants - over a distance of up to 20-30 km (in the form of hot water heat).

• Coal power plant in England

Cogeneration turbines

The main equipment of steam turbine thermal power plants is turbine units that convert the energy of the working substance (steam) into electrical energy, and boiler units that generate steam for turbines. The turbine unit includes a steam turbine and a synchronous generator. Steam turbines used in CHP plants are called combined heat and power turbines (CHTs). Among them, CTs are distinguished: with back pressure, usually equal to 0.7-1.5 Mn/m2 (installed at thermal power plants supplying steam industrial enterprises); with condensation and steam extraction under pressure of 0.7-1.5 Mn/m2 (for industrial consumers) and 0.05-0.25 Mn/m2 (for municipal consumers); with condensation and steam extraction (heating) under a pressure of 0.05-0.25 MN/m2.

The waste heat from backpressure CTs can be fully utilized. However, the electrical power developed by such turbines depends directly on the magnitude of the thermal load, and in the absence of the latter (as is, for example, the case in summer time at heating CHP plants) they do not generate electrical power. Therefore, CTs with back pressure are used only in the presence of a sufficiently uniform thermal load, ensured for the entire duration of the CHP operation (that is, mainly in industrial CHP plants).

In CTs with condensation and steam extraction, only extraction steam is used to supply heat to consumers, and the heat of the condensation steam flow is transferred to the cooling water in the condenser and is lost. To reduce heat losses, such CTs must operate most of the time according to the “thermal” schedule, that is, with minimal “ventilation” steam passage into the condenser. CTs with condensation and steam extraction have become predominantly widespread at thermal power plants as they are universal in possible operating modes. Their use makes it possible to regulate thermal and electrical loads almost independently; in a particular case, with reduced thermal loads or in their absence, a thermal power plant can operate according to an “electric” schedule, with the required, full or almost full electrical power.

Power of heating turbine units

The electrical power of heating turbine units (as opposed to condensing units) is preferably selected not according to a given power scale, but according to the amount of fresh steam they consume. Thus, turbine units R-100 with back pressure, PT-135 with industrial and heating extractions and T-175 with heating extraction have the same fresh steam consumption (about 750 t/h), but different electrical power (100, 135 and 175 MW, respectively) . The boiler units that produce steam for such turbines have the same productivity (about 800 t/h). This unification allows the use of turbine units at one CHP plant various types with the same thermal equipment of boilers and turbines. In the USSR, boiler units used to operate TPES for various purposes were also unified. Thus, boiler units with a steam output of 1000 t/h are used to supply steam to both 300 MW condensing turbines and the world’s largest 250 MW HPs.

The fresh steam pressure at thermal power plants is accepted in the USSR to be ~ 13-14 Mn/m 2 (mainly) and ~ 24-25 Mn/m 2 (at the largest heating power units - with a capacity of 250 MW). At thermal power plants with a steam pressure of 13-14 Mn/m 2, in contrast to state district power plants, there is no intermediate superheating of steam, since at such thermal power plants it does not provide such significant technical and economic advantages as at state regional power plants. Power units with a capacity of 250 MW at thermal power plants with a heating load are performed with intermediate superheating of steam.

The heat load at heating CHP plants is uneven throughout the year. In order to reduce costs for basic energy equipment, part of the heat (40-50%) during periods of increased load is supplied to consumers from peak water heating boilers. The share of heat released by the main power equipment at the highest load, determines the value of the heating coefficient of the thermal power plant (usually equal to 0.5-0.6). In a similar way, it is possible to cover the peaks of thermal (steam) industrial load (about 10-20% of the maximum) with peak steam

The operating principle of a combined heat and power plant (CHP) is based on unique property water vapor - to be a coolant. In a heated state, under pressure, it turns into powerful source energy driving the turbines of thermal power plants (TPPs) is a legacy of that already distant era of steam.

First thermal power plant was built in New York on Pearl Street (Manhattan) in 1882. A year later, St. Petersburg became the birthplace of the first Russian thermal station. Oddly enough, but even in our age high technology Thermal power plants have never found a full-fledged replacement: their share in the world energy sector is more than 60%.

And there is a simple explanation for this, which contains the advantages and disadvantages of thermal energy. Its “blood” is organic fuel - coal, fuel oil, oil shale, peat and natural gas are still relatively accessible, and their reserves are quite large.

The big disadvantage is that fuel combustion products cause serious harm to the environment. Yes, and the natural storehouse will one day be completely depleted, and thousands of thermal power plants will turn into rusting “monuments” of our civilization.

Principle of operation

To begin with, it is worth defining the terms “CHP” and “CHP”. In simple terms, they are sisters. A “clean” thermal power plant - TPP is designed exclusively for the production of electricity. Its other name is “condensing power plant” - IES.

Combined heat and power plant - CHP - a type of thermal power plant. In addition to generating electricity, it supplies hot water to central system heating and for domestic needs.

The operation scheme of a thermal power plant is quite simple. Fuel and heated air—an oxidizer—simultaneously enter the furnace. The most common fuel at Russian thermal power plants is crushed coal. The heat from the combustion of coal dust turns the water entering the boiler into steam, which is then supplied under pressure to the steam turbine. A powerful stream of steam causes it to rotate, driving the generator rotor, which converts mechanical energy to electric.

Next, the steam, which has already significantly lost its initial indicators - temperature and pressure - enters the condenser, where after a cold “water shower” it again becomes water. Then the condensate pump pumps it into the regenerative heaters and then into the deaerator. There, the water is freed from gases - oxygen and CO 2, which can cause corrosion. After this, the water is reheated from steam and fed back into the boiler.

Heat supply

The second, no less important function of the CHP is to provide hot water(ferry) intended for systems central heating nearby settlements And household use. In special heaters cold water heated to 70 degrees in summer and 120 degrees in winter, after which it is supplied to the shared cell mixing and then goes through the heating main system to consumers. Water supplies at the thermal power plant are constantly replenished.

How do gas powered thermal power plants work?

Compared to coal-fired thermal power plants, thermal power plants with gas turbine units are much more compact and environmentally friendly. Suffice it to say that such a station does not need a steam boiler. Gas turbine plant- this is essentially the same turbojet aircraft engine, where, unlike it, the jet stream is not emitted into the atmosphere, but rotates the generator rotor. At the same time, emissions of combustion products are minimal.

New coal combustion technologies

The efficiency of modern thermal power plants is limited to 34%. The vast majority of thermal power plants still operate on coal, which can be explained quite simply - coal reserves on Earth are still enormous, so the share of thermal power plants in the total volume of electricity generated is about 25%.

The coal combustion process has remained virtually unchanged for many decades. However, new technologies have come here too.

Peculiarity this method consists in the fact that instead of air, pure oxygen separated from the air is used as an oxidizer when burning coal dust. As a result, from flue gases harmful impurities – NOx – are removed. The remaining harmful impurities are filtered out through several stages of purification. The CO 2 remaining at the outlet is pumped into containers under high pressure and subject to burial at a depth of up to 1 km.

"oxyfuel capture" method

Here, too, when burning coal, pure oxygen is used as an oxidizing agent. Only in contrast to the previous method, at the moment of combustion, steam is formed, causing the turbine to rotate. Then ash and sulfur oxides are removed from the flue gases, cooling and condensation are performed. Remaining carbon dioxide under a pressure of 70 atmospheres is converted into liquid state and placed underground.

Pre-combustion method

Coal is burned in the “normal” mode - in a boiler mixed with air. After this, ash and SO 2 - sulfur oxide are removed. Next, CO 2 is removed using a special liquid absorbent, after which it is disposed of by burial.

Five of the most powerful thermal power plants in the world

The championship belongs to the Chinese thermal power plant Tuoketuo with a capacity of 6600 MW (5 power units x 1200 MW), occupying an area of ​​2.5 square meters. km. It is followed by its “compatriot” - the Taichung Thermal Power Plant with a capacity of 5824 MW. The top three is closed by the largest in Russia Surgutskaya GRES-2 - 5597.1 MW. In fourth place is the Polish Belchatow Thermal Power Plant - 5354 MW, and fifth is the Futtsu CCGT Power Plant (Japan) - a gas thermal power plant with a capacity of 5040 MW.

Electric energy has long entered our lives. Even the Greek philosopher Thales in the 7th century BC discovered that amber rubbed on wool begins to attract objects. But for a long time No one paid attention to this fact. Only in 1600 did the term “Electricity” first appear, and in 1650 Otto von Guericke created an electrostatic machine in the form of a sulfur ball mounted on a metal rod, which made it possible to observe not only the effect of attraction, but also the effect of repulsion. This was the first simple electrostatic machine.

Many years have passed since then, but even today, in a world filled with terabytes of information, when you can find out for yourself everything that interests you, for many it remains a mystery how electricity is produced, how it is delivered to our home, office, enterprise...

We will consider these processes in several parts.

Part I. Generation of electrical energy.

Where does it come from? Electric Energy? This energy appears from other types of energy - thermal, mechanical, nuclear, chemical and many others. On an industrial scale, electrical energy is obtained at power plants. Let's consider only the most common types of power plants.

1) Thermal power plants. Today, all of them can be combined under one term - State District Power Plant (State District Power Plant). Of course, today this term has lost its original meaning, but it has not gone into eternity, but has remained with us.

Thermal power plants are divided into several subtypes:

A) A condensing power plant (CPP) is a thermal power plant that produces only electrical energy; this type of power plant owes its name to the peculiarities of its operating principle.

Operating principle: Air and fuel (gaseous, liquid or solid) are supplied to the boiler using pumps. The result is a fuel-air mixture that burns in the boiler furnace, releasing a huge amount of heat. In this case, the water passes through a pipe system, which is located inside the boiler. The released heat is transferred to this water, while its temperature rises and is brought to a boil. The steam that was produced in the boiler goes back into the boiler to overheat it above the boiling point of water (at a given pressure), then through steam lines it goes to the steam turbine, in which the steam does work. At the same time, it expands, its temperature and pressure decrease. Thus, potential energy the steam is transferred to the turbine, which means it turns into kinetic steam. The turbine, in turn, drives the rotor of a three-phase alternating current generator, which is located on the same shaft as the turbine and produces energy.

Let's take a closer look at some elements of IES.

Steam turbine.

The flow of water vapor enters through guide vanes onto curved blades fixed around the circumference of the rotor, and, acting on them, causes the rotor to rotate. As you can see, there are gaps between the rows of shoulder blades. They are there because this rotor is removed from the housing. Rows of blades are also built into the body, but they are stationary and serve to create the desired angle of incidence of steam on the moving blades.

Condensing steam turbines are used to convert as much heat as possible from steam into mechanical work. They operate by releasing (exhausting) the spent steam into a condenser where a vacuum is maintained.

A turbine and generator that are located on the same shaft are called a turbogenerator. Three-phase alternating current generator (synchronous machine).

It consists of:

Which increases the voltage to the standard value (35-110-220-330-500-750 kV). In this case, the current decreases significantly (for example, when the voltage increases by 2 times, the current decreases by 4 times), which makes it possible to transmit power over long distances. It should be noted that when we talk about voltage class, we mean linear (phase-to-phase) voltage.

The active power produced by the generator is regulated by changing the amount of energy carrier, and the current in the rotor winding changes. To increase the output active power it is necessary to increase the steam supply to the turbine, and the current in the rotor winding will increase. We should not forget that the generator is synchronous, which means that its frequency is always equal to the frequency of the current in the power system, and changing the parameters of the energy carrier will not affect its rotation frequency.

In addition, the generator also produces reactive power. It can be used to regulate the output voltage within small limits (i.e. it is not the main means of regulating voltage in the power system). It works this way. When the rotor winding is overexcited, i.e. when the voltage on the rotor increases above the nominal value, “excess” reactive power is released into the power system, and when the rotor winding is underexcited, the reactive power is consumed by the generator.

Thus, in alternating current we are talking about total power (measured in volt-amperes - VA), which is equal to the square root of the sum of active (measured in watts - W) and reactive (measured in volt-amperes reactive - VAR) power.

The water in the reservoir serves to remove heat from the condenser. However, splash pools are often used for these purposes.

or cooling towers. Cooling towers can be tower type Fig.8

or fan Fig.9

Cooling towers are designed in almost the same way as those, with the only difference being that water flows over the radiators, transfers heat to them, and they are cooled by the forced air. In this case, part of the water evaporates and is carried into the atmosphere.
The efficiency of such a power plant does not exceed 30%.

B) Gas turbine power plant.

On gas turbine power plant The turbogenerator is driven not by steam, but directly by gases produced during fuel combustion. In this case, only natural gas can be used, otherwise the turbine will quickly fail due to its contamination with combustion products. Efficiency per maximum load 25-33%

Much greater efficiency (up to 60%) can be achieved by combining steam and gas cycles. Such plants are called combined-cycle plants. Instead of a conventional boiler, they have a waste heat boiler installed, which does not have its own burners. It receives heat from the exhaust of a gas turbine. Currently, CCGTs are being actively introduced into our lives, but so far there are few of them in Russia.

IN) Thermal power plants (have become an integral part of large cities a long time ago). Fig.11

The thermal power plant is structurally designed as a condensing power plant (CPS). The peculiarity of a power plant of this type is that it can generate both thermal and electrical energy simultaneously. Depending on the type of steam turbine, there are various ways steam extractions, which allow you to take steam from it with different parameters. In this case, part of the steam or all of the steam (depending on the type of turbine) enters the network heater, transfers heat to it and condenses there. Cogeneration turbines allow you to regulate the amount of steam for thermal or industrial needs, which allows the thermal power plant to operate in several load modes:

thermal - the production of electrical energy is completely dependent on the production of steam for industrial or district heating needs.

electrical - the electrical load is independent of the thermal load. In addition, CHP plants can operate in fully condensing mode. This may be required, for example, if there is a sharp shortage of active power in the summer. This mode is unprofitable for thermal power plants, because efficiency is significantly reduced.

The simultaneous production of electrical energy and heat (cogeneration) is a profitable process in which the efficiency of the station is significantly increased. For example, the calculated efficiency of CES is a maximum of 30%, and that of CHP is about 80%. Plus, cogeneration makes it possible to reduce idle thermal emissions, which has a positive effect on the ecology of the area in which the thermal power plant is located (compared to if there were a thermal power plant of similar capacity).

Let's take a closer look at the steam turbine.

To district heating steam turbines include turbines with:

Back pressure;

Adjustable steam extraction;

Selection and back pressure.

Turbines with back pressure operate by exhausting steam not into a condenser, like in IES, but into a network heater, that is, all the steam that goes through the turbine goes to heating needs. The design of such turbines has significant drawback: the electrical load schedule is completely dependent on the thermal load schedule, that is, such devices cannot take part in the operational regulation of the current frequency in the power system.

In turbines with regulated selection pair, its selection takes place the right amount in intermediate stages, while selecting such stages for steam selection that are suitable in in this case. This type of turbine is independent of the thermal load and the regulation of the output active power can be adjusted within greater limits than that of a back-pressure CHP plant.

Extraction and backpressure turbines combine the functions of the first two types of turbines.

Cogeneration turbines of CHP plants are not always unable to change the heat load in a short period of time. To cover load peaks, and sometimes to increase electrical power By switching turbines to condensing mode, peak water heating boilers are installed at thermal power plants.

2) Nuclear power plants.

In Russia there are currently 3 types of reactor plants. General principle their work is approximately similar to the work of IES (in the old days, nuclear power plants were called state district power plants). The only fundamental difference is that thermal energy produced not in boilers using fossil fuels, but in nuclear reactors.

Let's look at the two most common types of reactors in Russia.

1) RBMK reactor.

A distinctive feature of this reactor is that the steam for rotating the turbine is obtained directly in the reactor core.

RBMK core. Fig.13

consists of vertical graphite columns in which there are longitudinal holes, with zirconium alloy pipes inserted there and of stainless steel. Graphite acts as a neutron moderator. All channels are divided into fuel and CPS (control and protection system) channels. They have different cooling circuits. A cassette (FA - fuel assembly) with rods (TVEL - fuel element) inside which are uranium pellets in a hermetically sealed shell is inserted into the fuel channels. It is clear that it is from them that thermal energy is obtained, which is transferred to a coolant continuously circulating from bottom to top under high pressure - ordinary water, but very well purified from impurities.

Water, passing through the fuel channels, partially evaporates, the steam-water mixture enters from all individual fuel channels into 2 separator drums, where steam is separated from water. The water goes back into the reactor using circulation pumps(a total of 4 per loop), and the steam goes through steam lines to 2 turbines. The steam is then condensed in a condenser and turns into water, which goes back into the reactor.

The thermal power of the reactor is controlled only with the help of boron neutron absorber rods, which move in the control rod channels. The water cooling these channels comes from top to bottom.

As you may have noticed, I have never mentioned the reactor vessel yet. The fact is that, in fact, the RBMK does not have a hull. The active zone that I just told you about is placed in a concrete shaft, and on top it is closed with a lid weighing 2000 tons.

The above figure shows the upper biological protection of the reactor. But you shouldn’t expect that by lifting one of the blocks you will be able to see the yellow-green vent of the active zone, no. The cover itself is located significantly lower, and above it, in the space up to the upper biological protection, there remains a gap for communication channels and completely removed absorber rods.

Space is left between the graphite columns for thermal expansion of the graphite. A mixture of nitrogen and helium gases circulates in this space. Its composition is used to judge the tightness of the fuel channels. The RBMK core is designed to rupture no more than 5 channels; if more are depressurized, the reactor cover will tear off and the remaining channels will open. Such a development of events will cause a repetition of the Chernobyl tragedy (here I do not mean the man-made disaster, and its consequences).

Let's look at the advantages of the RBMK:

—Thanks to channel-by-channel regulation of thermal power, it is possible to change fuel assemblies without stopping the reactor. Every day, usually, several assemblies are changed.

—Low pressure in the CMPC (multiple circuit forced circulation), which contributes to a smoother occurrence of accidents associated with its depressurization.

— Absence of a difficult-to-manufacture reactor vessel.

Let's look at the disadvantages of the RBMK:

—During the operation, numerous errors were discovered in the geometry of the core, which cannot be completely eliminated at the existing power units of the 1st and 2nd generations (Leningrad, Kursk, Chernobyl, Smolensk). RBMK power units of the 3rd generation (there is only one - at the 3rd power unit of the Smolensk NPP) are free from these shortcomings.

—The reactor is single-circuit. That is, the turbines are rotated by steam produced directly in the reactor. This means that it contains radioactive components. When the turbine depressurizes (and this happened on Chernobyl nuclear power plant in 1993) its repair will be greatly complicated, and perhaps impossible.

—The service life of the reactor is determined by the service life of the graphite (30-40 years). Then comes its degradation, manifested in its swelling. This process is already causing serious concern at the oldest RBMK power unit, Leningrad-1, built in 1973 (it is already 39 years old). The most likely way out of the situation is to plug the nth number of channels to reduce the thermal expansion of graphite.

—Graphite moderator is a flammable material.

—Due to the huge number shut-off valves, the reactor is difficult to control.

— On the 1st and 2nd generations there is instability when operating at low powers.

In general, we can say that the RBMK is a good reactor for its time. At present, a decision has been made not to build power units with this type of reactor.

2) VVER reactor.

The RBMK is currently being replaced by VVER. It has significant advantages compared to the RBMK.

The core is completely contained in a very strong casing, which is manufactured at the factory and delivered by rail, and then by car to the power unit under construction in a completely finished form. The moderator is pure water under pressure. The reactor consists of 2 circuits: water from the first circuit under high pressure cools the fuel assemblies, transferring heat to the 2nd circuit using a steam generator (performs the function of a heat exchanger between 2 isolated circuits). In it, the secondary circuit water boils, turns into steam and goes to the turbine. In the first circuit, the water does not boil, since it is under very high pressure. The exhaust steam is condensed in the condenser and goes back to the steam generator. Double-circuit circuit has significant advantages compared to single-circuit:

The steam going to the turbine is not radioactive.

The reactor power can be controlled not only by absorber rods, but also by the solution boric acid, which makes the reactor more stable.

The primary circuit elements are located very close to each other, so they can be placed in a common containment shell. In case of ruptures in the primary circuit, radioactive elements will enter the containment and will not escape into environment. In addition, the containment shell protects the reactor from external influences (for example, from the fall of a small aircraft or an explosion outside the perimeter of the station).

The reactor is not difficult to operate.

There are also disadvantages:

—Unlike the RBMK, fuel cannot be changed while the reactor is running, because it is in general building, and not in separate channels, as in RBMK. The time of fuel reloading usually coincides with the time of routine repairs, which reduces the impact of this factor on the installed capacity factor.

—The primary circuit is under high pressure, which could potentially cause a larger scale accident during depressurization than the RBMK.

—The reactor vessel is very difficult to transport from the manufacturing plant to the nuclear power plant construction site.

Well, we have looked at the work of thermal power plants, now let’s look at the work

The operating principle of a hydroelectric power station is quite simple. Chain hydraulic structures provides the necessary pressure of water flowing to the blades of the hydraulic turbine, which drives the generators that produce electricity.

The required water pressure is formed through the construction of a dam, and as a result of the concentration of the river in a certain place, or by diversion - the natural flow of water. In some cases, to receive required pressure water is used jointly by both the dam and the diversion. Hydroelectric power plants have very high flexibility of generated power, as well as low cost of generated electricity. This feature of hydroelectric power plants led to the creation of another type of power plant - pumped storage power plant. Such stations are capable of accumulating generated electricity and using it at times of peak load. The operating principle of such power plants is as follows: at certain periods (usually at night), pumped storage power plant hydroelectric units operate like pumps, consuming electrical energy from the power system, and pumping water into specially equipped upper pools. When demand arises (during peak loads), water from them enters the pressure pipeline and drives the turbines. PSPPs perform an extremely important function in the energy system (frequency regulation), but they are not widely used in our country, because they end up consuming more power than they produce. That is, a station of this type is unprofitable for the owner. For example, at the Zagorskaya PSPP the capacity of hydro generators in generator mode is 1200 MW, and in pumping mode – 1320 MW. However, this type of station in the best possible way suitable for quickly increasing or decreasing generated power, so it is advantageous to build them near, for example, nuclear power plants, since the latter operate in basic mode.

We have looked at exactly how electrical energy is produced. It’s time to ask yourself a serious question: “What type of stations best meets all modern requirements for reliability, environmental friendliness, and, in addition, will also have a low energy cost?” Everyone will answer this question differently. Let me give you my list of the “best of the best”.

1) CHP powered by natural gas. The efficiency of such stations is very high, the cost of fuel is also high, but natural gas is one of the “cleanest” types of fuel, and this is very important for the ecology of the city, within the boundaries of which thermal power plants are usually located.

2) HPP and PSPP. The advantages over thermal stations are obvious, since this type of station does not pollute the atmosphere and produces the “cheapest” energy, which, in addition, is a renewable resource.

3) CCGT power plant using natural gas. The highest efficiency among thermal stations, as well as the small amount of fuel consumed, will partially solve the problem of thermal pollution of the biosphere and limited reserves of fossil fuels.

4) Nuclear power plant. In normal operation, a nuclear power plant emits 3-5 times less radioactive substances into the environment than a thermal station of the same power, so partial replacement of thermal power plants with nuclear ones is completely justified.

5) GRES. Currently, such stations use natural gas as fuel. This is absolutely meaningless, since with the same success it is possible to utilize associated waste in the furnaces of state district power plants. petroleum gas(APG) or burn coal, the reserves of which are huge compared to natural gas reserves.

This concludes the first part of the article.

Material prepared by:
student of group ES-11b South-West State University Agibalov Sergey.

The impeller blades of this steam turbine are clearly visible.

A thermal power plant (CHP) uses the energy released by burning fossil fuels - coal, oil and natural gas - to convert water into steam high pressure. This steam, having a pressure of about 240 kilograms per square centimeter and a temperature of 524°C (1000°F), drives the turbine. The turbine spins a giant magnet inside a generator, which produces electricity.

Modern thermal power plants convert about 40 percent of the heat released during fuel combustion into electricity, the rest is discharged into the environment. In Europe, many thermal power plants use waste heat to heat nearby homes and businesses. Combined heat and power generation increases the energy output of the power plant by up to 80 percent.

Steam turbine plant with electric generator

A typical steam turbine contains two sets of blades. High-pressure steam coming directly from the boiler enters the flow path of the turbine and rotates the impellers with the first group of blades. The steam is then heated in the superheater and again enters the turbine flow path to rotate impellers with a second group of blades, which operate at a lower steam pressure.

Sectional view

A typical thermal power plant (CHP) generator is driven directly by a steam turbine, which rotates at 3,000 revolutions per minute. In generators of this type, the magnet, also called the rotor, rotates, but the windings (stator) are stationary. The cooling system prevents the generator from overheating.

Power generation using steam

At a thermal power plant, fuel burns in a boiler, producing a high-temperature flame. The water passes through the tubes through the flame, is heated and turns into high-pressure steam. The steam spins a turbine, producing mechanical energy, which a generator converts into electricity. After leaving the turbine, the steam enters the condenser, where it washes the tubes with cold running water, and as a result turns back into liquid.

Oil, coal or gas boiler

Inside the boiler

The boiler is filled with intricately curved tubes through which heated water passes. The complex configuration of the tubes allows you to significantly increase the amount of heat transferred to the water and thereby produce much more steam.

An electric station is a set of equipment designed to convert the energy of any natural source into electricity or heat. There are several varieties of such objects. For example, thermal power plants are often used to generate electricity and heat.

Definition

A thermal power plant is an electric power plant that uses any fossil fuel as an energy source. The latter can be used, for example, oil, gas, coal. Currently, thermal complexes are the most common type of power plants in the world. The popularity of thermal power plants is explained primarily by the availability of fossil fuels. Oil, gas and coal are available in many parts of the planet.

TPP is (transcript from Its abbreviation looks like “thermal power plant”), among other things, a complex with a fairly high efficiency. Depending on the type of turbines used, this figure at stations of this type can be equal to 30 - 70%.

What types of thermal power plants are there?

Stations of this type can be classified according to two main criteria:

• purpose;
• type of installations.

In the first case, a distinction is made between state district power plants and thermal power plants.A GRES is a station that operates by rotating a turbine under a powerful stream of steam. The deciphering of the abbreviation GRES - state district power plant - has currently lost its relevance. Therefore, such complexes are often also called CES. This abbreviation stands for “condensing power plant”.

CHP is also a fairly common type of thermal power plant. Unlike state district power plants, such stations are equipped not with condensation turbines, but with heating turbines. CHP stands for "heat and power plant".

In addition to condensation and heating plants (steam turbine), thermal power plants can use following types equipment:

• steam-gas.

TPP and CHP: differences

Often people confuse these two concepts. CHP, in fact, as we found out, is one of the types of thermal power plants. Such a station differs from other types of thermal power plants primarily in thatpart of the thermal energy it generates goes to boilers installed in rooms to heat them or to produce hot water.

Also, people often confuse the names of hydroelectric power stations and state district power stations. This is primarily due to the similarity of abbreviations. However, a hydroelectric power station is fundamentally different from a state district power station. Both of these types of stations are built on rivers. However, at a hydroelectric power station, unlike state regional power plants, it is not steam that is used as an energy source, but the water flow itself.

What are the requirements for thermal power plants?

A thermal power plant is a thermal power station where electricity is generated and consumed simultaneously. Therefore, such a complex must fully comply with a number of economic and technological requirements. This will ensure uninterrupted and reliable supply of electricity to consumers. So:

• thermal power plant premises must have good lighting, ventilation and aeration;
• the air inside and around the plant must be protected from pollution by solid particles, nitrogen, sulfur oxide, etc.;
• water supply sources should be carefully protected from the ingress of wastewater;
• water treatment systems at stations should be equippedwaste-free.

Operating principle of thermal power plants

TPP is a power plant, on which turbines can be used different types. Next, we will consider the principle of operation of thermal power plants using the example of one of its most common types - thermal power plants. Energy is generated at such stations in several stages:

Fuel and oxidizer enter the boiler. Coal dust is usually used as the first one in Russia. Sometimes the fuel for thermal power plants can also be peat, fuel oil, coal, oil shale, and gas. In this case, the oxidizing agent is heated air.

The steam generated as a result of burning fuel in the boiler enters the turbine. The purpose of the latter is to convert steam energy into mechanical energy.

The rotating shafts of the turbine transmit energy to the shafts of the generator, which converts it into electricity.

The cooled steam that has lost some of its energy in the turbine enters the condenser.Here it turns into water, which is fed through heaters into the deaerator.

Deae The purified water is heated and supplied to the boiler.



Advantages of TPP

A thermal power plant is thus a station whose main type of equipment is turbines and generators. The advantages of such complexes include primarily:

• low cost of construction compared to most other types of power plants;
• cheapness of the fuel used;
• low cost of electricity generation.

Also a big plus It is believed that such stations can be built in any desired location, regardless of the availability of fuel. Coal, fuel oil, etc. can be transported to the station by road or rail.

Another advantage of thermal power plants is that they occupy a very small area compared to other types of stations.

Disadvantages of thermal power plants

Of course, such stations have not only advantages. They also have a number of disadvantages. Thermal power plants are complexes that, unfortunately, heavily pollute the environment. Stations of this type can emit huge amounts of soot and smoke into the air. Also, the disadvantages of thermal power plants include high operating costs. In addition, all types of fuel used at such stations are considered irreplaceable natural resources.

What other types of thermal power plants exist?

In addition to steam turbine thermal power plants and thermal power plants (GRES), the following stations operate in Russia:

Gas turbine (GTPP). In this case, the turbines do not rotate from steam, but from natural gas. Also, fuel oil or diesel fuel can be used as fuel at such stations. The efficiency of such stations, unfortunately, is not too high (27 - 29%). Therefore, they are mainly used only as backup sources electricity or intended to supply voltage to the network of small settlements.

Steam-gas turbine (SGPP). The efficiency of such combined stations is approximately 41 - 44%. In systems of this type, both gas and steam turbines simultaneously transmit energy to the generator. Like thermal power plants, combined hydroelectric power plants can be used not only for generating electricity itself, but also for heating buildings or providing consumers with hot water.

Examples of stations

So, any object can be considered quite productive and, to some extent, even universal. I am a thermal power plant, a power plant. Examples We present such complexes in the list below.

Belgorod Thermal Power Plant. The power of this station is 60 MW. Its turbines run on natural gas.

Michurinskaya CHPP (60 MW). This facility is also located in the Belgorod region and runs on natural gas.

Cherepovets GRES. The complex is located in the Volgograd region and can operate on both gas and coal. The power of this station is as much as 1051 MW.

Lipetsk CHPP-2 (515 MW). Powered by natural gas.

CHPP-26 "Mosenergo" (1800 MW).

Cherepetskaya GRES (1735 MW). The fuel source for the turbines of this complex is coal.

Instead of a conclusion

Thus, we found out what thermal power plants are and what types of such objects exist. The first complex of this type was built a long time ago - in 1882 in New York. A year later, such a system started working in Russia - in St. Petersburg. Today, thermal power plants are a type of power plant, which account for about 75% of all electricity generated in the world. And apparently, despite a number of disadvantages, stations of this type will provide the population with electricity and heat for a long time. After all, the advantages of such complexes are an order of magnitude greater than the disadvantages.