How does CHP work? Cherepetskaya gres. what does a modern coal power plant look like?

Climate Analytics continues to insist that coal power in Europe must be eliminated by 2030 - otherwise the EU will not meet the goals of the Paris climate agreement. But which stations should be closed first? Two approaches are proposed - environmental and economic. "Oxygen.LIFE" I took a closer look at the largest coal-fired power plants in Russia, which no one is going to close.

Close in ten years

Climate Analytics continues to insist that to achieve the goals of the Paris climate agreement, EU countries will have to close almost all existing coal-fired power plants. Europe's energy sector is in need of total decarbonization, as a significant portion of the EU's total greenhouse gas (GHG) emissions comes from coal-fired power. Therefore, phasing out coal in this industry is one of the most cost-effective methods for reducing GHG emissions, and such action will provide significant benefits in terms of air quality, public health and energy security.

Now in the EU there are more than 300 power plants with 738 power units operating on coal fuel. Naturally, they are not evenly distributed geographically. But overall, hard coal and lignite (brown coal) provide a quarter of all electricity generation in the EU. The most coal-dependent EU members are Poland, Germany, Bulgaria, the Czech Republic and Romania. Germany and Poland account for 51% of installed coal capacity in the EU and 54% of GHG emissions from coal power in the entire united Europe. At the same time, in seven EU countries there are no coal thermal power plants at all.

“The continued use of coal for electricity production is incompatible with the implementation of the task of sharply reducing GHG emissions. The EU therefore needs to develop a coal phase-out strategy faster than it currently does,” Climate Analytics concludes. Otherwise, total emissions across the EU will increase by 85% by 2050. Modeling by Climate Analytics found that 25% of currently operating coal-fired power plants would need to close by 2020. In another five years, it is necessary to close 72% of thermal power plants, and completely get rid of coal energy by 2030.

The main question is how to do this? According to Climate Analytics, “the critical question is what criteria should be used to determine when to close certain thermal power plants? From the point of view of the earth's atmosphere, the criteria do not matter, since GHG emissions will be reduced at the desired pace. But from the point of view of policymakers, business owners and other stakeholders, developing such criteria is a critical point in decision-making.”

Climate Analytics suggests two possible strategies for eliminating coal from electricity generation entirely. The first is to first close those thermal power plants that lead in GHG emissions. The second strategy is to close stations that are least valuable from a business perspective. For each of the strategies, there is an interesting infographic showing how the face of the EU will change in the years following the closure of coal plants. In the first case, Poland, the Czech Republic, Bulgaria and Denmark will be under attack. In the second there are also Poland and Denmark.

There is no unity

Climate Analytics also assigned the closure years for all 300 stations in accordance with two strategies. It is easy to notice that these years differ significantly from the operating times of these stations as usual (the so-called BAU - businnes as usual). For example, Europe's largest Belchatov station in Poland (capacity of more than 4.9 GW) can operate at least until 2055; whereas it is proposed to close it by 2027 - the same period under any scenario.

In general, it is precisely the five Polish thermal power plants that can quietly smoke until the 2060s that Climate Analytics proposes to close three to four decades ahead of schedule. Poland, whose energy supply is 80% dependent on coal, is unlikely to be happy with this development (remember, this country is even going to challenge the climate obligations imposed on it by the EU in court). Another five stations in the Top 20 are in the UK; eight are in Germany. Also in the top twenty for closure are two thermal power plants in Italy.

At the same time, the English Fiddler's Ferry (capacity 2 GW) should be closed already in 2017, and the rest of the British thermal power plants, as stated by the government of this country, by 2025. That is, only in this country can the process take place relatively painlessly. In Germany everything can stretch until 2030, the implementation of the two strategies will differ depending on the specifics of the land (there are coal mining regions). In the Czech Republic and Bulgaria, coal generation will need to be phased out by 2020 - primarily due to significant emissions.

Renewable energy sources should replace coal. Reducing the cost of solar and wind generation is an important trend that needs to be supported and developed, according to Climate Analytics. Thanks to renewable energy sources, it is possible to transform the energy sector, including by creating new jobs (not only in the industry itself, but also in the production of equipment). Which, among other things, will be able to employ personnel released from the coal energy sector.

However, Climate Analytics admits that there is no unity in Europe regarding coal. While some countries have significantly reduced production and announced a complete phase-out of this type of fuel in the next 10-15 years (among them, for example, the UK, Finland and France), others are either building or planning to build new coal-fired power plants (Poland and Greece). “Ecological issues are given a lot of attention in Europe, but it will hardly be possible to quickly abandon coal generation. First, it is necessary to put into operation replacement capacities, because both the population and the economy need heat and light. This is all the more important given that earlier decisions were made to close a number of nuclear power plants in Europe. Social problems will arise, some of the employees of the stations themselves will need to be retrained, a significant number of jobs will be cut in a variety of industries, which will certainly increase tension in society. The closure of coal power plants will also have an impact on budgets, since there will be no significant group of taxpayers, and the operating performance of those companies that previously supplied them with goods and services will decrease significantly. If any solution is possible, it may consist in a time-extended abandonment of coal generation, while simultaneously continuing work to improve technologies in order to reduce emissions from coal combustion and improve the environmental situation at coal power plants,” he says on this occasion. Dmitry Baranov, leading expert of Finam Management.

Top 20 coal-fired power plants in Europe, which, according to Climate Analytics, will need to be closed

What do we have?

The share of thermal generation in the structure of electricity generation in Russia is more than 64%, in the structure of the installed capacity of UES stations - more than 67%. However, in the TOP 10 largest thermal power plants in the country, only two stations operate on coal - Reftinskaya and Ryazanskaya; Basically, thermal energy in Russia is gas. “Russia has one of the best fuel balance structures in the world. We use only 15% coal for energy production. The global average is 30-35%. In China – 72%, in the USA and Germany – 40%. The task of reducing the share of non-carbon sources to 30% is being actively addressed in Europe. In Russia, this program has, in fact, already been implemented,” said the head of the Russian Ministry of Energy Alexander Novak, speaking at the end of February at the panel session “Green Economy as a Vector of Development” as part of the Russian Investment Forum 2017 in Sochi.

The share of nuclear energy in the country’s total energy balance is 16-17%, hydropower generation is 18%, and gas accounts for about 40%. According to the Institute of Energy Research of the Russian Academy of Sciences, coal in electricity production has long been actively replaced by gas and nuclear power, and most rapidly in the European part of Russia. The largest coal thermal power plants are located, however, in the center and in the Urals. But if you look at the picture in the energy sector in terms of regions, and not individual stations, the picture will be different: the most “coal” regions are in Siberia and the Far East. The structure of territorial energy balances depends on the level of gasification: in the European part of Russia it is high, and in Eastern Siberia and beyond it is low. Coal as a fuel is usually used in urban thermal power plants, where not only electricity is generated, but also heat. Therefore, generation in large cities (like Krasnoyarsk) is completely based on coal fuel. In general, thermal stations in the Siberian IPS alone currently account for 60% of electricity generation - this is about 25 GW of “coal” capacity.

As for renewable energy sources, the share of such sources in the energy balance of the Russian Federation now accounts for a symbolic 0.2%. “We plan to reach 3% - up to 6 thousand MW through various support mechanisms,” Novak forecast. The Rosseti company gives more optimistic forecasts: the installed capacity of renewable energy sources in Russia may increase by 10 GW by 2030. However, a global restructuring of the energy balance in our country is not expected. “It is predicted that by 2050 there will be about 10 billion people in the world. Already today, about 2 billion do not have access to energy sources. Imagine what humanity’s need for energy will be in 33 years, and how renewable energy sources should develop to meet all demand,” Alexander Novak proves the viability of traditional energy.

“We are definitely not talking about “giving up coal” in Russia, especially since, according to the Energy Strategy until 2035, it is planned to increase the share of coal in the country’s energy balance,” recalls Dmitry Baranov from Finam Management. - Along with oil and gas, coal is one of the most important minerals on the planet, and Russia, as one of the largest countries in the world in terms of its reserves and production, is simply obliged to pay due attention to the development of this industry. Back in 2014, at a meeting of the Russian government, Novak presented a program for the development of the Russian coal industry until 2030. It focuses on creating new coal mining centers, primarily in Siberia and the Far East, improving scientific and technical potential in the industry, as well as implementing projects in the coal chemistry.”

The largest thermal power plants in Russia operating on coal fuel

Reftinskaya GRES (Enel Russia)

It is the largest coal-fired thermal power plant in Russia (and second in the top 10 thermal power plants in the country). Located in the Sverdlovsk region, 100 km northeast of Yekaterinburg and 18 km from Asbest.
Installed electrical capacity is 3800 MW.
Installed thermal power - 350 Gcal/h.
Provides energy supply to industrial areas of the Sverdlovsk, Tyumen, Perm and Chelyabinsk regions.
Construction of the power plant began in 1963, the first power unit was launched in 1970, and the last in 1980.

Ryazanskaya GRES (OGK-2)

Fifth in the top 10 largest thermal stations in Russia. It runs on coal (first stage) and natural gas (second stage). Located in Novomichurinsk (Ryazan region), 80 km south of Ryazan.
Installed electrical capacity (together with GRES-24) is 3,130 MW.
Installed thermal power is 180 Gcal/hour.
Construction began in 1968. The first power unit was put into operation in 1973, the last one on December 31, 1981.

Novocherkasskaya GRES (OGK-2)

Located in the Donskoy microdistrict in Novocherkassk (Rostov region), 53 km southeast of Rostov-on-Don. Runs on gas and coal. The only thermal power plant in Russia that uses local waste from coal mining and coal preparation - anthracite pellets.
Installed electrical capacity is 2229 MW.
Installed thermal power is 75 Gcal/hour.
Construction began in 1956. The first power unit was put into operation in 1965, the last - the eighth - in 1972.

Kashirskaya GRES (InterRAO)

Located in Kashira (Moscow region).
Powered by coal and natural gas.
Installed electrical capacity is 1910 MW.
Installed thermal power - 458 Gcal/h.
Commissioned in 1922 according to the GOELRO plan. In the 1960s, the station underwent large-scale modernization.
Pulverized coal power units No. 1 and No. 2 are planned to be decommissioned in 2019. By 2020, the same fate awaits four more power units operating on gas-oil fuel. Only the most modern unit No. 3 with a capacity of 300 MW will remain in operation.

Primorskaya GRES (RAO ES Vostoka)

Located in Luchegorsk (Primorsky Territory).
The most powerful thermal power plant in the Far East. Powered by coal from the Luchegorsk coal mine. Provides most of Primorye's energy consumption.
Installed electrical capacity is 1467 MW.
Installed thermal power is 237 Gcal/hour.
The first power unit of the station was put into operation in 1974, the last one in 1990. The GRES is located practically “on board” a coal mine - nowhere else in Russia has a power plant been built in such close proximity to a fuel source.

Troitskaya GRES (OGK-2)

Located in Troitsk (Chelyabinsk region). Advantageously located in the industrial triangle Ekaterinburg - Chelyabinsk - Magnitogorsk.
Installed electrical capacity is 1,400 MW.
Installed thermal power - 515 Gcal/hour.
The launch of the first stage of the station took place in 1960. The equipment of the second stage (1200 MW) was decommissioned in 1992-2016.
In 2016, a unique pulverized coal power unit No. 10 with a capacity of 660 MW was put into operation.

Gusinoozerskaya GRES (InterRAO)

Located in Gusinoozersk (Republic of Buryatia), it provides electricity to consumers in Buryatia and neighboring regions. The main fuel for the station is brown coal from the Okino-Klyuchevsky open-pit mine and the Gusinoozersk deposit.
Installed electrical capacity is 1160 MW.
Installed thermal power - 224.5 Gcal/h.
Four power units of the first stage were put into operation from 1976 to 1979. Commissioning of the second stage began in 1988 with the launch of power unit No. 5.

CHP is a thermal power plant that not only produces electricity, but also provides heat to our homes in winter. Using the example of the Krasnoyarsk Thermal Power Plant, let’s see how almost any thermal power plant works.

There are 3 thermal power plants in Krasnoyarsk, the total electrical power of which is only 1146 MW (for comparison, our Novosibirsk CHPP 5 alone has a capacity of 1200 MW), but what was remarkable for me was Krasnoyarsk CHPP-3 because the station is new - not even a year has passed , as the first and so far only power unit was certified by the System Operator and put into commercial operation. Therefore, I was able to photograph the still dusty, beautiful station and learn a lot about the thermal power plant.

In this post, in addition to technical information about KrasTPP-3, I want to reveal the very principle of operation of almost any combined heat and power plant.

1. Three chimneys, the height of the highest one is 275 m, the second highest is 180 m

The abbreviation CHP itself implies that the station produces not only electricity, but also heat (hot water, heating), and heat generation may even be a higher priority in our country, which is known for its harsh winters.

2. The installed electrical capacity of Krasnoyarsk CHPP-3 is 208 MW, and the installed thermal capacity is 631.5 Gcal/h

In a simplified way, the operating principle of a thermal power plant can be described as follows:

It all starts with fuel. Coal, gas, peat, and oil shale can be used as fuel at different power plants. In our case, this is B2 brown coal from the Borodino open-pit mine, located 162 km from the station. Coal is transported by rail. Part of it is stored, the other part goes along conveyors to the power unit, where the coal itself is first crushed to dust and then fed into the combustion chamber - the steam boiler.

A steam boiler is a unit for producing steam at a pressure above atmospheric pressure from feed water continuously supplied to it. This happens due to the heat released during fuel combustion. The boiler itself looks quite impressive. At KrasCHETS-3, the height of the boiler is 78 meters (26-story building), and it weighs more than 7,000 tons.

6. Steam boiler brand Ep-670, manufactured in Taganrog. Boiler capacity 670 tons of steam per hour

I borrowed a simplified diagram of a power plant steam boiler from the website energoworld.ru so that you can understand its structure

1 - combustion chamber (furnace); 2 - horizontal gas duct; 3 - convective shaft; 4 - combustion screens; 5 - ceiling screens; 6 — drain pipes; 7 - drum; 8 – radiation-convective superheater; 9 — convective superheater; 10 - water economizer; 11 — air heater; 12 — blower fan; 13 — lower screen collectors; 14 - slag chest of drawers; 15 — cold crown; 16 - burners. The diagram does not show the ash collector and smoke exhauster.

7. View from above

10. The boiler drum is clearly visible. The drum is a cylindrical horizontal vessel having water and steam volumes, which are separated by a surface called the evaporation mirror.

Due to its high steam output, the boiler has developed heating surfaces, both evaporative and superheating. Its firebox is prismatic, quadrangular with natural circulation.

A few words about the principle of operation of the boiler:

Feed water enters the drum, passing through the economizer, and goes down through the drain pipes into the lower collectors of the pipe screens. Through these pipes, the water rises and, accordingly, heats up, since a torch burns inside the firebox. The water turns into a steam-water mixture, part of it goes into the remote cyclones and the other part back into the drum. In both cases, this mixture is divided into water and steam. The steam goes into the superheaters, and the water repeats its path.

11. Cooled flue gases (approximately 130 degrees) exit the furnace into electric precipitators. In electric precipitators, gases are purified from ash, the ash is removed to an ash dump, and the purified flue gases escape into the atmosphere. The effective degree of flue gas purification is 99.7%.
The photo shows the same electrostatic precipitators.

Passing through superheaters, the steam is heated to a temperature of 545 degrees and enters the turbine, where under its pressure the turbine generator rotor rotates and, accordingly, electricity is generated. It should be noted that in condensing power plants (GRES) the water circulation system is completely closed. All steam passing through the turbine is cooled and condensed. Having turned into a liquid state again, the water is reused. But in the turbines of a thermal power plant, not all the steam enters the condenser. Steam extraction is carried out - production (use of hot steam in any production) and heating (hot water supply network). This makes CHP more economically profitable, but it has its drawbacks. The disadvantage of combined heat and power plants is that they must be built close to the end consumer. Laying heating mains costs a lot of money.

12. Krasnoyarsk CHPP-3 uses a direct-flow technical water supply system, which makes it possible to abandon the use of cooling towers. That is, water for cooling the condenser and used in the boiler is taken directly from the Yenisei, but before that it undergoes purification and desalting. After use, the water is returned through the canal back to the Yenisei, passing through a dissipative release system (mixing heated water with cold water in order to reduce thermal pollution of the river)

14. Turbogenerator

I hope I was able to clearly describe the operating principle of a thermal power plant. Now a little about KrasTPP-3 itself.

Construction of the station began back in 1981, but, as happens in Russia, due to the collapse of the USSR and crises, it was not possible to build a thermal power plant on time. From 1992 to 2012, the station worked as a boiler house - it heated water, but it learned to generate electricity only on March 1 of last year.

Krasnoyarsk CHPP-3 belongs to Yenisei TGC-13. The thermal power plant employs about 560 people. Currently, Krasnoyarsk CHPP-3 provides heat supply to industrial enterprises and the housing and communal sector of the Sovetsky district of Krasnoyarsk - in particular, the Severny, Vzlyotka, Pokrovsky and Innokentyevsky microdistricts.

17.

19. CPU

20. There are also 4 hot water boilers at KrasTPP-3

21. Peephole in the firebox

23. And this photo was taken from the roof of the power unit. The large pipe has a height of 180m, the smaller one is the pipe of the starting boiler room.

24. Transformers

25. A 220 kV closed gas-insulated switchgear (GRUE) is used as a switchgear at KrasTPP-3.

26. Inside the building

28. General view of the switchgear

29. That's all. Thank you for your attention

Until yesterday, in my mind, all coal power plants were about the same and were ideal horror movie sets. With structures blackened by time, boilers, turbines, millions of different pipes and their cunning plexuses with a generous layer of black coal dust. Rare workers, more like miners, are repairing some complex units in the scanty lighting of green gas lamps, here and there, hissing, clouds of steam and smoke are escaping, thick puddles of dark-colored liquids have spilled on the floor, something is dripping everywhere. This is how I saw coal stations and thought that their age was already passing. The future belongs to gas, I thought.

It turns out not at all.

Yesterday I visited the newest coal power unit of the Cherepetskaya State District Power Plant in the Tula region. It turns out that modern coal plants are not grimy at all, and the smoke from their chimneys is not thick or black.

1. A few words about the operating principle of GRES. Water, fuel and atmospheric air are supplied to the boiler using pumps under high pressure. The combustion process occurs in the boiler furnace - the chemical energy of the fuel is converted into thermal energy. Water flows through a pipe system located inside the boiler.

2. Burning fuel is a powerful source of heat that is transferred to water, which is heated to boiling point and evaporates. The resulting steam in the same boiler is overheated above the boiling point, to approximately 540 °C, and under high pressure of 13–24 MPa, it is supplied to the steam turbine through one or more pipelines.

3. The steam turbine, electric generator and exciter make up the whole turbine unit. In a steam turbine, steam expands to a very low pressure (about 20 times less than atmospheric pressure), and the potential energy of the compressed and heated steam is converted into kinetic energy of rotation of the turbine rotor. The turbine drives an electric generator, which converts the kinetic energy of rotation of the generator rotor into electric current.

4. Water is taken directly from the Cherepetskoye reservoir.

5. The water undergoes chemical purification and deep desalting so that deposits do not appear on the internal surfaces of equipment in steam boilers and turbines.

6. Coal and fuel oil are delivered to the station by rail.

7. At an open coal warehouse, loader cranes unload wagons. Then the big one comes into play and feeds it onto the conveyor.

8. This way the coal enters the sections of the crushing plant for preliminary grinding of the coal and subsequent pulverization. Coal is supplied to the boiler itself in the form of a mixture of coal dust and air.

10. The boiler plant is located in the boiler room of the main building. The boiler itself is something ingenious. A huge complex mechanism as tall as a 10-story building.

14. You can walk through the labyrinths of the boiler plant forever. The time allotted for filming had already run out twice, but it was impossible to tear yourself away from this industrial beauty!

16. Galleries, elevator shafts, passages, stairs and bridges. In a word - space)

17. The rays of the sun illuminated a tiny man against the backdrop of everything that was happening, and I couldn’t help but think that all these complex giant structures were invented and built by a man. This little man came up with ten-story furnaces to generate electricity from minerals on an industrial scale.

18. Beauty!

19. Behind the wall from the boiler plant there is a machine room with turbo generators. Another gigantic room, more spacious.

20. Yesterday, power unit No. 9 was solemnly put into operation, which was the final stage of the Cherepetskaya GRES expansion project. The project included the construction of two modern pulverized coal power units with a capacity of 225 MW each.

21. The guaranteed electrical capacity of the new power unit is 225 MW;
Electrical efficiency - 37.2%;
The specific consumption of equivalent fuel for electricity generation is 330 g/kWh.

23. The main equipment includes two steam condensing turbines manufactured by OJSC Power Machines and two boiler units manufactured by OJSC EMAlliance. The main fuel of the new power unit is Kuznetsk hard coal of the DG grade.

24. Control room.

25. The power units are equipped with the first integrated dry dust and desulfurization system for flue gases with electrostatic filters on the Russian market.

26. Outdoor switchgear transformers.

28. The commissioning of a new power unit will make it possible to decommission the outdated coal-fired equipment of the first stage without reducing the volume of electricity generation and the total installed capacity of the station.

29. Along with the new power unit, two 87-meter cooling towers were built - part of the process water supply system, which supplies large quantities of cold water to cool the turbine condensers.

30. Seven spans of 12 meters. From below, this height does not seem so serious.

31. On the upper platform of the chimney it was both hot and cool at the same time. The camera constantly fogged up.

32. View of the power unit from the cooling tower. The new power capacities of the station are designed in such a way as to significantly reduce emissions of pollutants, reduce dust emissions when working at a coal warehouse, reduce the amount of water consumed, and also eliminate the possibility of environmental pollution from wastewater.

34. Inside the cooling tower everything turned out to be quite simple and boring)

36. The photo clearly shows the new power unit and two old ones. How the chimney of the old power unit and the new one smokes. Gradually, the old power units will be decommissioned and dismantled. So it goes.

At thermal power plants, people receive almost all the energy they need on the planet. People have learned to receive electric current in a different way, but still do not accept alternative options. Even if it is unprofitable for them to use fuel, they do not refuse it.

What is the secret of thermal power plants?

Thermal power plants It is no coincidence that they remain indispensable. Their turbine produces energy in the simplest way, using combustion. Due to this, it is possible to minimize construction costs, which are considered completely justified. There are such objects in all countries of the world, so one should not be surprised at the spread.

Operating principle of thermal power plants built on burning huge volumes of fuel. As a result, electricity appears, which is first accumulated and then distributed to certain regions. Thermal power plant patterns remain almost constant.

What fuel is used at the station?

Each station uses a separate fuel. It is specially supplied so that the workflow is not disrupted. This point remains one of the problematic ones, as transportation costs arise. What types of equipment does it use?

• Coal;
• Oil shale;
• Peat;
• Fuel oil;
• Natural gas.

Thermal circuits of thermal power plants are built on a specific type of fuel. Moreover, minor changes are made to them to ensure maximum efficiency. If they are not done, the main consumption will be excessive, and therefore the resulting electric current will not be justified.

Types of thermal power plants

The types of thermal power plants are an important issue. The answer to it will tell you how the necessary energy appears. Today, serious changes are gradually being made, where alternative types will be the main source, but so far their use remains inappropriate.

1. Condensing (IES);
2. Combined heat and power plants (CHP);
3. State district power plants (GRES).

The thermal power plant will require a detailed description. The types are different, so only consideration will explain why construction of such a scale is carried out.

Condensing (IES)

Types of thermal power plants begin with condensing ones. Such thermal power plants are used exclusively for generating electricity. Most often, it accumulates without immediately spreading. The condensation method provides maximum efficiency, so similar principles are considered optimal. Today, in all countries, there are separate large-scale facilities that supply vast regions.

Nuclear plants are gradually appearing, replacing traditional fuel. Only replacement remains an expensive and time-consuming process, since working on fossil fuels differs from other methods. Moreover, shutting down a single station is impossible, because in such situations entire regions are left without valuable electricity.

Combined heat and power plants (CHP)

CHP plants are used for several purposes at once. They are primarily used to generate valuable electricity, but burning fuels also remains useful for generating heat. Due to this, cogeneration power plants continue to be used in practice.

An important feature is that such thermal power plants are superior to other types with relatively low power. They supply specific areas, so there is no need for bulk supplies. Practice shows how beneficial such a solution is due to the laying of additional power lines. The operating principle of a modern thermal power plant is unnecessary only because of the environment.

State district power plants

General information about modern thermal power plants GRES is not noted. Gradually they remain in the background, losing their relevance. Although state-owned district power plants remain useful in terms of energy output.

Different types of thermal power plants provide support to vast regions, but still their power is insufficient. During the Soviet era, large-scale projects were carried out, which are now being closed. The reason was inappropriate use of fuel. Although their replacement remains problematic, since the advantages and disadvantages of modern thermal power plants are primarily noted for the large volumes of energy.

Which power plants are thermal? Their principle is based on burning fuel. They remain indispensable, although calculations are actively underway for equivalent replacement. Thermal power plants continue to prove their advantages and disadvantages in practice. Because of which their work remains necessary.

Fuel, cold water and air are what a thermal power plant consumes. Ash, hot water, smoke and electricity are what it produces.

Thermal power plants operate on various types of fuel.

In the central zone of the Soviet Union, many power plants operate on local fuel - peat. It is burned in the furnaces of steam boilers in lump form on moving grates or in the form of peat chips - milled peat - in mine-mill furnaces or furnaces of the engineering system. Shershneva.

Milled peat is obtained by removing small shavings and crumbs from the peat mass using toothed drums - cutters. Then this crumb is dried.

The combustion of milled peat in its pure form remained an unresolved problem for a long time, until in the USSR engineer Shershnev designed a firebox in which milled peat is burned in suspension. Milled peat is blown into the firebox by air. Unburnt large particles fall, but are again picked up by a strong stream of air and, thus, remain suspended in the combustion chamber until complete combustion.

In 1931, the world's first power plant was launched in the USSR, burning milled peat in such furnaces. This is the Bryansk regional power plant.

Later, mine-mill furnaces were designed to burn milled peat. In shaft mills, milled peat is dried, crushed, mixed with air and, in the form of very small dried particles, enters the furnace, where it burns.

In the oil regions of the USSR there are also power plants that operate on liquid fuel - fuel oil (waste from oil distillation). Power plants located near metallurgical plants consume blast furnace gas and coke oven gas as fuel. With the discovery of natural gas deposits, some power plants began to use this gas in the furnaces of their boilers.

But none of these fuels are as common as coal. Most thermal power plants in the USSR consume various types of coal as fuel.

Modern power plants are very unpretentious to the quality of coal. They can use high-ash and high-grade coals, which are unsuitable for combustion in the furnaces of steamships and locomotives, in blast furnaces and open-hearth furnaces.

Previously, at power plants, coal was burned in the furnaces of steam boilers on grates - the same as in kilns for sod peat and firewood. Practice has shown that it is much more profitable to burn coal in the form of fine powder - coal dust. To obtain it, coal is ground in mills. It is dried in the same mills. Most modern thermal power plants run on coal dust.

A thermal power plant requires a very large amount of water. Steam boilers need to be powered. But most of the water is used to cool the exhaust steam and condense it.

Modern large thermal power plants are mostly built on the banks of a river, lake or specially created pond. But there is not always a sufficient amount of water in the place where the power plant is built. In this case, they are content with a small reservoir, where the water is artificially cooled using spray pools or cooling towers.

Fig. 4-4. Distribution of losses and useful energy in a steam turbine power plant.

Numbers from 7 to 6 show losses: 1 - losses in the boiler (wasted into the surrounding air and into heating the boiler room); 2-losses with flue gases;^- losses in steam pipelines; 4 - losses in the turbine and for heating the turbine room; 5 - losses in the generator; 6 - losses with cooling water.

In a condensing power plant, internal and cooling water losses are 77%. At a combined heat and power plant, part of the heat contained in the selected and exhaust steam of turbines is used in industrial enterprises 7 and for domestic needs 8. The total losses are 65%.

Warm water comes under pressure to the spray pools. A pipe system distributes this water among a number of nozzles. Water comes out of them in small fountains, is sprayed into small splashes, cooled by the surrounding air, and, already cooled, falls into the pool.

Cooling towers are tall towers that are hollow inside. In their lower part there are gratings around the circumference. Warm water pours onto the grates in a fine rain. The air passes through this artificial rain, is heated by the heat of the water and, together with water vapor, enters the central part of the cooling tower. This giant pipe creates draft. Warm air rises and is thrown out. There are always huge clouds of steam above the cooling towers.

Combined heat and power plants - abbreviated CHP - are power plants that, in addition to electricity, also provide heat to consumers in the form of steam for the technological needs of factories and factories and in the form of hot water used for heating homes and household needs of the population.

Combined heat and power plants are much more economical than simple or, as they are called, condensing power plants. In the latter, more than half of the heat produced by burning fuel is carried away with the cooling water. At thermal power plants, these losses are much less, since part of the steam exhausted in the turbines goes directly to consumers and to heat water for heating and hot water supply to the surrounding area.

So, the most common one in the USSR is a thermal power plant that runs on coal burned in the furnaces of steam boilers in a pulverized state. This is the power plant we will visit.

Fuel supplied

In order to generate 1 kWh of electricity at a modern power plant, only a few hundred grams of coal are consumed, but even an “average” power plant consumes several thousand tons of coal per day.

Now the gates of the power plant have opened and, clanging their buffers, another train of heavy Figs slowly enters. 4-5. technological process of a thermal power plant (fuel supply and boiler room). 1 lump coal, fed in self-unloading cars into the bunkers of the unloading shed, through the conveyor system 2, enters the bunkers 3 of the crushing tower and through the magnetic separator 4 and the grate screen 5 into the crusher 6, where it is crushed into pieces measuring 10-13 ΛίΛί. After the crusher, fine coal is fed through conveyor 2 to the conveyors of the bunker gallery 7 and through them into the raw coal bunkers of the boilers 8.

From the raw coal bunkers, through a belt feeder 9 combined with a belt scale, the coal enters a ball mill 10, where it is ground and dried by flue gases supplied to the mill through a gas pipeline 11. The mixture of coal dust and gases is sucked out of the mill by a mill fan (exhauster) 12, passes through the mill separator 13, where large dust particles are separated and returned through the dust line 14 back to the mill. Fine dust with gases enters the left cyclone 15, where the dust is separated from the gases and poured into the dust hopper 16. From the dust cyclone 15, gases are sucked out through a gas pipeline 17 and through a burner 19

They are blown into the boiler furnace 20.

In the same flow of gases, through dust feeders 18, the amount of dust required for a given boiler load is added. Blower fan 21 takes heated air from the upper part of the boiler room, drives it through air heater 22, where the air is brought to a temperature of 300 - ^50 °, and supplies it in the amount necessary for complete combustion of dust through air boxes 23 to burners 19. Fire torches , leaving the burners, have a temperature of about 1,500°. The hot flue gases formed during the combustion of dust give off part of their heat by radiation to the screen pipes 24, are sucked out of the firebox by the smoke exhauster 29 and are thrown out into the chimney 31 through the hog 30.

On the way from the furnace, gases wash boiling pipes 25, superheater 26, water heater - water economizer 27 and air heater 22. The gas temperature drops below 200°. In electric precipitators 28, exhaust gases are cleaned of ash, which is poured together with slag from the furnace into hydraulic ash removal channels 12, from which it is carried away by a powerful stream of water.

Water enters the boiler from the turbine room through the feedwater pipeline 33, passes through the water economizer 27, where it is heated to approximately the boiling point for a given pressure, fed into the boiler drum 34 and from there fills the entire pipe system. The resulting steam is discharged from the upper part of the boiler balaban through steam removal pipes 35 into the superheater 26. The superheated steam through the main steam valve 37 along the superheated steam steam line 36 goes to the turbine room to the turbines.

four-axle self-unloading gondolas. Everyone is capable! hold up to 60 tons of coal.

The train is fed to carriage scales, where each gondola is weighed. Weighing fuel is necessary to maintain accurate records of the technical and economic indicators of the power plant’s operation and monetary settlements with the railway and supplier mines.

After weighing, some of the cars go to the coal warehouse, where they are unloaded to create coal reserves. A warehouse is needed in case of possible transport disruptions.

The coal warehouses of the power plant are equipped with powerful loading and unloading mechanisms - portal cranes, cable cranes, steam or electric self-propelled grab cranes. Downtime of wagons during loading and unloading is reduced to a minimum.

Depending on fuel supply conditions, the warehouse stores a quantity of coal that is sufficient to ensure the station operates at full load for several days or even weeks.

The other part of the cars, which remained at the carriage scales, is picked up by the station locomotive I 1 and delivered to a long building - the unloading shed. The large double doors of the unloading shed open, the warning lights come on, the bell rings, and the entire train, along with the locomotive, goes inside for unloading.

Workers turn the locking levers, open the lower side shields of the gondolas and a black stream of coal pours into large pits covered with large-mesh iron grates located on both sides of the railway track. These are unloading bunkers. The powerful electric lamps under the ceiling seem dim from the rising clouds of dust. The coal was served dry, which is why there are so many Figs. 4-6. technological process (continuation of Fig. 4-5). thermal power plant (machine room and electrical part).

Superheated steam from the boilers through steam line 1 enters steam turbine 2, where the thermal energy of the steam is converted into mechanical energy. The turbine rotor rotates the generator rotor L connected to it. The steam exhausted in the turbine enters 4, where it liquefies - condenses, giving up its heat to the circulating water. The steam turned into water - condensate - is pumped out by condensate pump b and sent to storage tanks 7 and deaerator b, in which oxygen is removed from the heated water. In addition to condensate, water is added to the deaerator '4 through pipeline 12 from chemical water treatment to compensate for condensate losses, and drainage from collecting drain tanks 10 is supplied here by transfer pump 9. Depending on the water consumption of the boiler room, condensate is either accumulated in the storage tank or consumed from it to the deaerator. The release of water from oxygen dissolved in it occurs when passing the deaerator head 11.

The feed pump /5 takes water from the deaerator and, under pressure, drives it through the heater 14, where the water is heated by the exhaust steam of the turbine and goes through the feed water pressure pipeline 15 to the boiler room to the boilers. Exhaust steam from the turbine, in addition to the heater, is also supplied to the deaerator head.

A powerful circulation pump 16 pumps cold water (circulation water) through the brass pipes 5 of the condenser. The exhaust steam from the turbine washes these tubes, gives off its heat to the circulating water and condenses. Warm circulating water through pipeline 17 enters the outlet 18 of the cooling tower, flows from there along the grate 19 in the form of fine rain and, meeting the flow of air going into the tower 20 of the cooling tower, is cooled and from the receiving pool 2/, already cooled, returns to the suction circulation pump 16.

From the generator stator, the generated electrical energy by cable 22 through the generator disconnectors 23 and the oil switch 24 is discharged to the busbars of the switchgear 27. From the busbars, part of the electricity through step-down auxiliary transformers is used to power auxiliary electric motors and to illuminate the station. The main part of the electricity through step-up transformers 26 and oil switches 27 goes along the high-voltage line 28 to the general high-voltage line.

power system network.

dust. But it also happens differently. In autumn and winter, when there is heavy rain and snowfall, the moisture content of coal increases enormously. The coal freezes and has to be knocked out of the gondolas with crowbars.

From the unloading bunkers, coal through a system of belt conveyors, first underground and then rising upward along inclined galleries, enters the crushing tower. Here hammer crushers crush it into pieces measuring 10-13 mm. From here the coal goes to the raw coal bunkers of steam boilers. This ends the operation of the fuel supply workshop.

Steam Factory

When you stand downstairs in the boiler room, in the passage between the boilers, it seems as if you are on a narrow street between tall buildings. Only the houses are of an unusual appearance, clad in black-painted steel sheets and surrounded by light lattice steel walkways and stairs. Modern boilers reach the height of a five-story building.

On all sides, the boiler has a smooth black casing. Only at the very top is a silver dome visible, as if an airship was built inside the cauldron. This is the boiler drum. The dome of the steel drum is covered with a layer of thermal insulation and painted with aluminum bronze. The dome has a hatch so that you can climb inside the drum during installation and repair.

In several places on the boiler casing there are small peek-a-boo doors. Let's open one of them. Your face immediately becomes hot, and the unbearably bright light hits your eyes. The peepholes go into the boiler furnace, where fuel combustion occurs. Opposite one of the open burners there is a black tube with a glass lens at the end, like half a binocular. This is an optical pyrometer that measures the temperature in the firebox. A sensitive sensor is placed inside the pyrometer tube. Wires from it go to a galvanometer mounted on the control heat panel of the boiler. The galvanometer scale is graduated in degrees.

The temperature inside the boiler furnace is more than one and a half thousand degrees, and the lining of its walls is only warm. The flame in the firebox is surrounded on all sides by a series of pipes filled with water and connected to the boiler drum. These pipes - the water screen, as they are called - receive the radiant energy of the hot gases of the firebox. Behind the screen pipes there is a masonry of refractory bricks. Behind the layer of refractory brick is a layer of insulating diatomite brick with very low thermal conductivity. And behind this brick, directly under the steel sheathing panels, there is another layer of glass wool or asbestos. The pipes leaving the boiler are covered with a thick layer of thermal insulation. All these measures significantly reduce heat loss to the environment.

Inside the firebox

A nearby boiler was stopped for repairs. Through an opening in its wall you can go inside the firebox to a temporary plank platform made for the duration of the repair. How gray everything is inside!

All four walls of the firebox are covered with water screen pipes. The pipes are covered with a layer of loose ash and slag. In some places on the side walls of the firebox, the pipes are separated and gaping black holes are visible - burners, through which coal dust is blown into the firebox:

At the bottom, the walls of the firebox narrow in the form of an overturned pyramid, turning into a narrow shaft. This is a slag bunker and a slag mine. The slag formed during the combustion of coal dust falls here. From slag mines, slag and ash are washed off with a strong stream of water into hydraulic ash removal channels or poured into trolleys and transported to ash dumps.

When you stand at the bottom of the firebox, poor lighting initially conceals the height of the firebox space. But this height becomes noticeable if you look around one of the pipes of the water screen from the very bottom to the top.

Down at the platform level, the pipes seem to be as thick as an arm and the spaces between them are clearly visible. At the top the roughs bend, forming a flat arch. And up there, these pipes seem like straws laid in even rows. You have to tilt your head back to inspect the arch of the firebox. Involuntarily, the mouth opens and ash pours into it.

When the boiler is operating, all its water pipes are continuously covered with a layer of soot, a layer of ash and soot. This impairs heat transfer from hot gases to water in the pipes. During a boiler repair, all of its water pipes are thoroughly cleaned.

Steam boiler designers adjust the speed of hot gases flying through the tube bundles to be high enough to reduce the deposition of particulates on them. Otherwise, growths would have formed, similar to stalactites and stalagmites in caves.

In addition, while the boiler is operating, it is necessary to blow its pipes from time to time with a strong jet of compressed air or steam.

The volume of the boiler furnace is more than a thousand cubic meters. It’s scary to think what’s going on in this huge space during the operation of the boiler, when it’s all filled with raging flames and whirlwinds of hot gases.