Thermal power plant is a power plant that generates electrical energy as a result of the conversion of thermal energy released during the combustion of organic fuel (Fig. E.1).

There are thermal steam turbine power plants (TPES), gas turbine power plants (GTPP) and combined cycle power plants (CGPP). Let's take a closer look at TPES.

Fig.D.1 TPP diagram

At TPES, thermal energy is used in a steam generator to produce high-pressure water steam, which drives a steam turbine rotor connected to an electric generator rotor. The fuel used at such thermal power plants is coal, fuel oil, natural gas, lignite (brown coal), peat, and shale. Their efficiency reaches 40%, power – 3 GW. TPES that have condensing turbines as a drive for electric generators and do not use the heat of exhaust steam to supply thermal energy to external consumers are called condensing power plants (the official name in the Russian Federation is the State District Electric Station, or GRES). State district power plants generate about 2/3 of the electricity produced at thermal power plants.

TPES equipped with heating turbines and releasing the heat of exhaust steam to industrial or municipal consumers are called combined heat and power plants (CHP); they generate about 1/3 of the electricity produced at thermal power plants.

There are four known types of coal. In order of increasing carbon content, and thereby calorific value these types are arranged as follows: peat, lignite, bituminous (fat) coal or hard coal and anthracite. In the operation of thermal power plants, mainly the first two types are used.

Coal is not chemically pure carbon; it also contains inorganic material (brown coal contains up to 40% carbon), which remains after the combustion of coal in the form of ash. Coal may contain sulfur, sometimes as iron sulfide and sometimes as part of the organic components of coal. Coal usually contains arsenic, selenium, and radioactive elements. In fact, coal turns out to be the dirtiest of all fossil fuels.

When coal is burned, carbon dioxide, carbon monoxide, as well as large quantities of sulfur oxides, suspended particles and nitrogen oxides are formed. Sulfur oxides damage trees, various materials and have a harmful effect on people.

The particles released into the atmosphere when coal is burned in power plants are called "fly ash." Ash emissions are strictly controlled. About 10% of suspended particles actually enter the atmosphere.

A 1000 MW coal-fired power plant burns 4-5 million tons of coal per year.

Since there is no coal mining in the Altai Territory, we will assume that it is brought from other regions, and roads are built for this purpose, thereby changing the natural landscape.

APPENDIX E

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 state district power plant is a station that operates by rotating a turbine under the powerful pressure of a steam jet. Explanation of the abbreviation GRES - state-owned district power plant- has now 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 supplied through heaters to the deaerator.

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



Advantages of TPP

A thermal power plant is therefore 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 advantage of such stations is that they 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, are very polluting 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 compared to hydroelectric power plants. 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 rotate not 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 of 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 State District Power Plant. 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.

Basic structural unit at most power plants it is shop . At thermal stations, there are workshops of main, auxiliary production and non-industrial facilities.

· The main production workshops produce the products for which the enterprise was created. At thermal power plants, the main ones are the workshops in which production processes to convert the chemical energy of fuel into thermal and electrical energy.

· The auxiliary production workshops of industrial enterprises, including power plants, are not directly related to the production of the main products of the enterprise: they serve the main production, contribute to the production of products and provide the main production with the necessary conditions for normal operation. These shops repair equipment, supply materials, tools, devices, spare parts, water (industrial), various types of energy, transport, etc.

· Non-industrial enterprises are those whose products and services do not relate to the main activities of the enterprise. Their functions include providing and servicing the household needs of the enterprise personnel ( housing estates, childcare facilities, etc.).

The production structures of a thermal station are determined by the power ratio of the main units (turbine units, steam boilers, transformers) and the technological connections between them. Decisive when determining the control structure is the power ratio and communication between turbines and boiler units. At existing power plants of medium and low power, homogeneous units are connected to each other by pipelines for steam and water (steam from boilers is collected in common collecting lines, from which it is distributed between individual boilers). This technological scheme is called centralized . Also widely used sectional a scheme in which a turbine with one or two boilers providing it with steam forms a section of a power plant.

• With such schemes, equipment is distributed among workshops that combine homogeneous equipment: in the boiler shop - boiler units with auxiliary equipment; turbine - turbine units with auxiliary equipment, etc. According to this principle, the following workshops and laboratories are organized at large thermal power plants: fuel transport, boiler, turbine, electrical (with an electrical laboratory), automation and thermal control workshop (laboratory), chemical (with a chemical laboratory), mechanical (when performing repairs of the power plant, this workshop becomes a mechanical repair shop), repair and construction shop.

Currently, due to the peculiarities of the technological process of energy production, stations with units with a capacity of 200...800 MW and above are used block equipment connection diagram. In block power plants, a turbine, a generator, a boiler (or two boilers) with auxiliary equipment form a block; there are no pipelines connecting the units for steam and water between the units; backup boiler units are not installed at power plants. Change technological scheme power plant leads to the need to reorganize the production management structure, in which the main primary production unit is the unit.

· For block-type stations the most rational management structure is shopless (functional) with the organization of an operation service and a repair service, headed by service heads - deputy chief engineer of the station. Functional departments report directly to the station director, and functional services and laboratories report directly to the station chief engineer.

· At large block-type stations, an intermediate management structure - block-shop . The boiler and turbine shops are combined into one and the following shops are organized: fuel and transport, chemical, thermal automation and measurements, centralized repairs, etc. When the station operates on gas, the fuel and transport shop is not organized.

Organizational and production structure of hydroelectric power plants

At a hydroelectric power station, there is both management of individual hydroelectric power stations and its associations located on the same river (canal) or simply in any administrative or economic area; such associations are called cascade (Fig. 23.2).

Organizational structure of HPP management:

A- 1st and 2nd groups; 1 - director of the hydroelectric power station; 2 - deputy director for administrative and economic activities; 3 - deputy Director of Capital Construction; 4 - HR department; 5 - chief engineer; 6 - accounting; 7 - planning department; 8 - civil defense department; 2.1 - transport section; 2.2 - logistics department; 2.3 - administrative and economic department; 2.4 - housing and communal services department; 2.5 - protection of hydroelectric power stations; 5.1 - deputy Ch. operational engineer; 5.2 - head of the electrical department; 5.3 - head of the turbine shop; 5.4 - head of the hydraulic department; 5.5 - production and technical department; 5.6 - communication service; 5.7 - operation and safety engineer; 5.2.1 - electrical engineering laboratory; b- 3rd and 4th groups; 1 - logistics department; 2 - production and technical department (PTO); 3 - accounting; 4 - hydraulic workshop; 5 - electrical machine shop

Organizational structure for managing a cascade of hydroelectric power plants: A - option 1; 1 - head of the electrical department of the cascade; 2 - head of the cascade turbine shop; 3 - head of the hydraulic department of the cascade; 4 - head of technical department; 5 - head of GES-1; 6 - head of GES-2; 7 - head of GES-3; 8 - communication service; 9 - local relay protection and automation service; 10 - engineer-inspector for operation and safety; 5.1, 6.1, 7.1 - production personnel at GES-1, 2, 3, respectively; b- option 2; 1 - cascade director; 2 - administrative divisions of the cascade; 3 - chief engineer; 3.1, 3.2, 3.3 - head of HPP-1, 2, 3, respectively; 3.1.1, 3.2.1, 3.3.1 - production units, including operating personnel, respectively, GES-1, 2, 3

Depending on the power of the hydroelectric power station and the hydroelectric power station cascades, MW, according to the management structure, it is customary to consider six groups and the same number of hydroelectric power station cascades:

• IN first four groups mainly used shop organizational management structure . At a hydroelectric power station and its cascades of the 1st and 2nd groups, as a rule, electrical, turbine and hydraulic workshops are provided; 3rd and 4th groups - electric turbine and hydraulic;
• At low power hydroelectric power stations ( 5th group ) apply shopless management structures with the organization of relevant areas;
• At hydroelectric power plants and cascades with a capacity of up to 25 MW ( 6th group ) - only operational and repair personnel .

When organizing a cascade of hydroelectric power stations, one of the cascade stations, usually the largest in power, is chosen as the base station, where the cascade management, its departments and services, workshops, main central warehouses and workshops are located. With a shop management structure, each shop services the equipment and structures of all hydroelectric power plants included in the cascade, and the personnel are located either at the base hydroelectric power station or distributed among the stations of the cascade. In cases where the hydroelectric power stations of the cascade are located at a considerable distance from each other and, accordingly, from the base one, it is necessary to appoint those responsible for the operation of the hydroelectric power station included in the cascade.

When combining large-capacity hydroelectric power plants into a cascade, it is advisable to centralize only management functions (cascade management, accounting, supply, etc.). At each hydroelectric power station, workshops are organized that carry out full operational and repair maintenance. When carrying out major repair work, for example during the overhaul of units, part of the workers of the corresponding workshop from one or more hydroelectric power stations is transferred to the station where it is necessary.

Thus, a rational management structure in each case is adopted based on the specific conditions for the formation of the cascade. If there are a large number of hydroelectric power stations included in the cascade, a preliminary consolidation of stations located closest to each other, headed by the head of the hydroelectric power station group, is used. Each group independently carries out operational maintenance, including routine repairs of equipment and structures.

Definition

cooling tower

Characteristics

Classification

Combined heat and power plant

Mini-CHP device

Purpose of mini-CHP

Use of heat from mini-CHP

Fuel for mini-CHP

Mini-CHP and ecology

Gas turbine engine

Combined-cycle plant

Operating principle

Advantages

Spreading

Condensing power plant

Story

Operating principle

Basic systems

Environmental impact

Current state

Verkhnetagilskaya GRES

Kashirskaya GRES

Pskovskaya GRES

Stavropol State District Power Plant

Smolenskaya GRES

Thermal power plant is(or thermal power station) is a power plant that generates electrical energy by converting the chemical energy of fuel into the mechanical energy of rotation of the electric generator shaft.

The main components of a thermal power plant are:

Engines - power units thermal power station

Electric generators

Heat exchangers TPP - thermal power plants

Cooling towers.

cooling tower

Cooling tower (German: gradieren - to thicken brine; originally, cooling towers were used to extract salt by evaporation) - a device for cooling a large amount of water with a directed flow of atmospheric air. Sometimes cooling towers are also called cooling towers.

Currently, cooling towers are mainly used in circulating water supply systems for cooling heat exchangers (usually at thermal power plants, CHP plants). In civil engineering, cooling towers are used in air conditioning, for example, to cool the condensers of refrigeration units, to cool emergency power generators. In industry, cooling towers are used to cool refrigeration machines, plastic molding machines, and chemical purification of substances.

Cooling occurs due to the evaporation of part of the water when it flows in a thin film or drops along a special sprinkler, along which an air flow is supplied in the direction opposite to the movement of water. When 1% of water evaporates, the temperature of the remaining water drops by 5.48 °C.

As a rule, cooling towers are used where it is not possible to use large bodies of water (lakes, seas) for cooling. Besides, this method cooling is more environmentally friendly.

A simple and cheap alternative to cooling towers are spray ponds, where water is cooled by simple spraying.

Characteristics

The main parameter of the cooling tower is the value of irrigation density - the specific value of water consumption per 1 m² of irrigation area.

The main design parameters of cooling towers are determined by technical and economic calculations depending on the volume and temperature of the cooled water and atmospheric parameters (temperature, humidity, etc.) at the installation site.

Use of cooling towers in winter time, especially in harsh climatic conditions, can be dangerous due to the possibility of freezing of the cooling tower. This happens most often in the place where frosty air comes into contact with a large number warm water. To prevent freezing of the cooling tower and, accordingly, its failure, it is necessary to ensure uniform distribution of cooled water over the surface of the sprinkler and monitor the same density of irrigation in individual areas of the cooling tower. Blower fans are also often susceptible to icing due to improper use of the cooling tower.

Classification

Depending on the type of sprinkler, cooling towers are:

film;

drip;

splash;

By air supply method:

ventilatory (thrust is created by a fan);

tower (thrust is created using a high exhaust tower);

open (atmospheric), using the power of wind and natural convection as air moves through the sprinkler.

Fan cooling towers are the most effective from a technical point of view, as they provide deeper and higher-quality water cooling and can withstand large specific heat loads (however, they require costs electrical energy to drive fans).

Types

Boiler-turbine power plants

Condensing power plants (GRES)

Combined heat and power plants (cogeneration power plants, combined heat and power plants)

Gas turbine power plants

Power plants based on combined cycle gas plants

Power plants based on piston engines

Compression ignition (diesel)

Spark ignited

Combined cycle

Combined heat and power plant

Combined heat and power plant (CHP) is a type of thermal power plant that produces not only electricity, but is also a source of thermal energy in centralized systems heat supply (in the form of steam and hot water, including for providing hot water supply and heating of residential and industrial facilities). As a rule, a thermal power plant must operate according to a heating schedule, that is, the production of electrical energy depends on the production of thermal energy.

When placing a thermal power plant, the proximity of heat consumers in the form of hot water and steam is taken into account.

Mini-CHP

Mini-CHP is a small combined heat and power plant.

Mini-CHP device

Mini-CHPs are thermal power plants used for the joint production of electrical and thermal energy in units with a unit capacity of up to 25 MW, regardless of the type of equipment. Currently, the following installations are widely used in foreign and domestic thermal power engineering: back-pressure steam turbines, condensing steam turbines with steam extraction, gas turbine plants with water or steam recovery of thermal energy, gas piston, gas-diesel and diesel units with recovery of thermal energy of various systems of these units. The term cogeneration plants is used as a synonym for the terms mini-CHP and CHP, but it has a broader meaning, as it implies joint production (co - joint, generation - production) various products, which can be both electrical and thermal energy, and other products, for example, thermal energy and carbon dioxide, electrical energy and cold, etc. In fact, the term trigeneration, which implies the production of electricity, thermal energy and cold, is also a special case of cogeneration . A distinctive feature of mini-CHP is the more economical use of fuel for the produced types of energy in comparison with conventional separate methods of their production. This is due to the fact that electricity nationwide, it is produced mainly in the condensation cycles of thermal power plants and nuclear power plants, which have an electrical efficiency of 30-35% in the absence of thermal acquirer. In fact, this state of affairs is determined by the existing ratio of electrical and thermal loads of populated areas, their different character changes throughout the year, as well as the inability to transfer thermal energy over long distances, unlike electrical energy.

The mini-CHP module includes a gas piston, gas turbine or diesel engine, generator electricity, a heat exchanger for recovering heat from water while cooling the engine, oil and exhaust gases. A hot water boiler is usually added to a mini-CHP to compensate for the heat load at peak times.

Purpose of mini-CHP

The main purpose of mini-CHP is to generate electrical and thermal energy from various types fuel.

The concept of constructing a mini-CHP in close proximity to to the acquirer has a number of advantages (compared to large thermal power plants):

allows you to avoid expenses to build the advantages of costly and dangerous high-voltage power lines;

losses during energy transmission are eliminated;

there is no need for financial costs to meet technical conditions for connecting to networks

centralized power supply;

uninterrupted supply of electricity to the purchaser;

power supply with high-quality electricity, compliance with specified voltage and frequency values;

perhaps making a profit.

IN modern world The construction of mini-CHP is gaining momentum, the advantages are obvious.

Use of heat from mini-CHP

A significant part of the energy of fuel combustion during electricity generation is thermal energy.

There are options for using heat:

direct use of thermal energy by end consumers (cogeneration);

hot water supply (DHW), heating, technological needs (steam);

partial conversion of thermal energy into cold energy (trigeneration);

the cold is generated by an absorption refrigeration machine that consumes not electrical, but thermal energy, which makes it possible to use heat quite efficiently in the summer for air conditioning or for technological needs;

Fuel for mini-CHP

Types of fuel used

gas: mains, Natural gas liquefied and other flammable gases;

liquid fuel: diesel fuel, biodiesel and other flammable liquids;

solid fuel: coal, wood, peat and other types of biofuels.

The most efficient and inexpensive fuel in the Russian Federation is mainline Natural gas, as well as associated gas.

Mini-CHP and ecology

The use of waste heat from power plant engines for practical purposes is distinctive feature mini-CHP and is called cogeneration (heating).

The combined production of two types of energy at mini-CHPs contributes to a much more environmentally friendly use of fuel compared to the separate generation of electricity and thermal energy at boiler plants.

Replacing boiler houses that irrationally use fuel and pollute the atmosphere of cities and towns, mini-CHPs contribute not only to significant fuel savings, but also to increasing the cleanliness of the air basin and improving the overall environmental condition.

The energy source for gas piston and gas turbine mini-CHPs is usually . Natural or associated gas, organic fuel that does not pollute the atmosphere with solid emissions

Gas turbine engine

Gas turbine engine (GTE, TRD) is a heat engine in which gas is compressed and heated, and then the energy of the compressed and heated gas is converted into mechanical energy work on the shaft of a gas turbine. Unlike a piston engine, in a gas turbine engine processes occur in a flow of moving gas.

Compressed atmospheric air from the compressor enters the combustion chamber, and fuel is supplied there, which, when burned, forms a large amount of combustion products under high pressure. Then, in the gas turbine, the energy of the combustion gases is converted into mechanical energy work due to the rotation of the blades by the gas jet, part of which is spent on compressing the air in the compressor. The rest of the work is transferred to the driven unit. The work consumed by this unit is the useful work of the gas turbine engine. Gas turbine engines have the highest power density among internal combustion engines, up to 6 kW/kg.

The simplest gas turbine engine has only one turbine, which drives the compressor and at the same time is a source of useful power. This imposes restrictions on engine operating modes.

Sometimes the engine is multi-shaft. In this case, there are several turbines in series, each of which drives its own shaft. The high-pressure turbine (the first after the combustion chamber) always drives the engine compressor, and subsequent ones can drive both an external load (helicopter or ship propellers, powerful electric generators, etc.) and additional compressors of the engine itself, located in front of the main one.

The advantage of a multi-shaft engine is that each turbine operates at the optimal speed and load Advantage load driven from the shaft of a single-shaft engine, the engine's acceleration, that is, the ability to spin up quickly, would be very poor, since the turbine needs to supply power both to provide the engine with a large amount of air (power is limited by the amount of air) and to accelerate the load. With a two-shaft design, a lightweight high-pressure rotor quickly comes into operation, providing the engine with air and the low-pressure turbine with a large amount of gases for acceleration. It is also possible to use a less powerful starter for acceleration when starting only the high pressure rotor.

Combined-cycle plant

A combined cycle plant is an electricity generating station used to produce heat and electricity. It differs from steam power and gas turbine plants in its increased efficiency.

Operating principle

A combined cycle plant consists of two separate units: steam power and gas turbine. In a gas turbine unit, the turbine is rotated by gaseous products of fuel combustion. The fuel can be either Natural gas or petroleum products. industry (fuel oil, diesel fuel). On the same shaft with the turbine there is a first generator, which, due to the rotation of the rotor, generates electric current. Passing through the gas turbine, the combustion products give it only part of their energy and still have a high temperature at the exit from the gas turbine. From the exit of the gas turbine, combustion products enter the steam power plant, the waste heat boiler, where water and the resulting water vapor are heated. The temperature of the combustion products is sufficient to bring the steam to the state necessary for use in a steam turbine (the flue gas temperature of about 500 degrees Celsius allows one to obtain superheated steam at a pressure of about 100 atmospheres). The steam turbine drives a second electric generator.

Advantages

Combined-cycle plants have an electrical efficiency of about 51-58%, while for separately operating steam power or gas turbine plants it fluctuates around 35-38%. This not only reduces fuel consumption, but also reduces greenhouse gas emissions.

Since a combined cycle plant extracts heat from combustion products more efficiently, it is possible to burn fuel at a higher high temperatures, as a result, the level of nitrogen oxide emissions into the atmosphere is lower than that of other types of installations.

Relatively low cost production.

Spreading

Despite the fact that the advantages of the steam-gas cycle were first proven back in the 1950s by the Soviet academician Khristianovich, this type of power generating installations was not widely used. Russian Federation wide application. Several experimental CCGT units were built in the USSR. An example is the power units with a capacity of 170 MW at the Nevinnomysskaya GRES and 250 MW at the Moldavskaya GRES. IN recent years V Russian Federation a number of powerful combined cycle power units. Among them:

2 power units with a capacity of 450 MW each at the North-Western Thermal Power Plant in St. Petersburg;

1 power unit with a capacity of 450 MW at the Kaliningrad CHPP-2;

1 CCGT unit with a capacity of 220 MW at Tyumen CHPP-1;

2 CCGT units with a capacity of 450 MW at CHPP-27 and 1 CCPP at CHPP-21 in Moscow;

1 CCGT unit with a capacity of 325 MW at Ivanovskaya GRES;

2 power units with a capacity of 39 MW each at Sochi TPP

As of September 2008, several CCPPs are in various stages of design or construction in the Russian Federation.

In Europe and the USA, similar installations operate at most thermal power plants.

Condensing power plant

A condensing power plant (CPP) is a thermal power plant that produces only electrical energy. Historically, it received the name “GRES” - state district power plant. Over time, the term “GRES” has lost its original meaning (“district”) and in the modern sense means, as a rule, a high-capacity condensing power plant (CPP) (thousands of MW), operating in the unified energy system along with other large power plants. However, it should be taken into account that not all stations with the abbreviation “GRES” in their names are condensing stations; some of them operate as combined heat and power plants.

Story

The first GRES Elektroperedacha, today's GRES-3, was built near Moscow in Elektrogorsk in 1912-1914. on the initiative of engineer R. E. Klasson. The main fuel is peat, power is 15 MW. In the 1920s, the GOELRO plan provided for the construction of several thermal power plants, among which the Kashirskaya State District Power Plant is the most famous.

Operating principle

Water, heated in a steam boiler to the state of superheated steam (520-565 degrees Celsius), rotates a steam turbine that drives a turbogenerator.

Excess heat is released into the atmosphere (nearby bodies of water) through condensing units, in contrast to cogeneration power plants, which release excess heat for the needs of nearby objects (for example, heating houses).

A condensing power plant typically operates according to the Rankine cycle.

Basic systems

IES is complex energy complex, consisting of buildings, structures, power and other equipment, pipelines, fittings, instrumentation and automation. The main IES systems are:

boiler plant;

steam turbine plant;

fuel economy;

system for ash and slag removal, flue gas purification;

electrical part;

technical water supply (to remove excess heat);

chemical cleaning and water treatment system.

When designing and constructing a CES, its systems are located in buildings and structures of the complex, primarily in the main building. When operating IES, the personnel managing the systems, as a rule, are united in workshops (boiler-turbine, electrical, fuel supply, chemical water treatment, thermal automation, etc.).

The boiler plant is located in the boiler room of the main building. In the southern regions of the Russian Federation, the boiler installation may be open, that is, without walls and a roof. The installation consists of steam boilers (steam generators) and steam pipelines. Steam from the boilers is transferred to the turbines through live steam lines. Steam lines of various boilers, as a rule, are not connected by cross connections. This type of scheme is called “block”.

The steam turbine unit is located in the machine room and in the deaerator (bunker-deaerator) compartment of the main building. It includes:

steam turbines with an electric generator on the same shaft;

a condenser in which the steam that has passed through the turbine is condensed to form water (condensate);

condensate and feed pumps that ensure the return of condensate (feed water) to steam boilers;

low and high pressure recuperative heaters (LHP and PHH) - heat exchangers in which feed water is heated by steam extraction from the turbine;

deaerator (also used as HDPE), in which water is purified from gaseous impurities;

pipelines and auxiliary systems.

The fuel economy has a different composition depending on the main fuel for which the IES is designed. For coal-fired CPPs, the fuel economy includes:

defrosting device (the so-called “heathouse” or “shed”) for thawing coal in open gondola cars;

unloading device (usually a car dumper);

a coal warehouse serviced by a grab crane or a special reloading machine;

crushing plant for preliminary grinding of coal;

conveyors for moving coal;

aspiration systems, blocking and other auxiliary systems;

dust preparation system, including ball, roller, or hammer coal grinding mills.

The dust preparation system, as well as coal bunkers, are located in the bunker-deaerator compartment of the main building, the remaining fuel supply devices are located outside the main building. Occasionally, a central dust plant is set up. The coal warehouse is designed for 7-30 days of continuous operation of the IES. Some fuel supply devices are redundant.

The fuel economy of IES using Natural gas is the simplest: it includes a gas distribution point and gas pipelines. However, at such power plants, it is used as a backup or seasonal source. fuel oil, so a fuel oil farm is being set up. A fuel oil facility is being built at coal power plants, where it is used for lighting boilers. The fuel oil industry includes:

receiving and draining device;

fuel oil storage facility with steel or reinforced concrete tanks;

fuel oil pumping station with fuel oil heaters and filters;

pipelines with shut-off and control valves;

fire and other auxiliary systems.

The ash and slag removal system is installed only at coal-fired power plants. Both ash and slag are non-combustible coal residues, but the slag is formed directly in the boiler furnace and is removed through a tap hole (a hole in the slag shaft), and the ash is carried away with the flue gases and is captured at the boiler exit. Ash particles are significantly smaller in size (about 0.1 mm) than slag pieces (up to 60 mm). Ash removal systems can be hydraulic, pneumatic or mechanical. The most common system of recirculating hydraulic ash and slag removal consists of flushing devices, channels, tank pumps, slurry pipelines, ash and slag dumps, pumping stations and clarified water conduits.

The release of flue gases into the atmosphere is the most dangerous impact of a thermal power plant on surrounding nature. To collect ash from flue gases, various types of filters are installed after blower fans (cyclones, scrubbers, electric precipitators, bag fabric filters) that retain 90-99% of solid particles. However, they are not suitable for cleaning smoke from harmful gases. Abroad, and in lately and at domestic power plants (including gas and fuel oil), systems are installed for gas desulfurization with lime or limestone (the so-called deSOx) and the catalytic reduction of nitrogen oxides with ammonia (deNOx). The purified flue gas is emitted by a smoke exhauster into a chimney, the height of which is determined from the conditions for the dispersion of remaining harmful impurities in the atmosphere.

The electrical part of the IES is intended for the production of electrical energy and its distribution to consumers. IES generators create a three-phase electric current with a voltage of usually 6-24 kV. Since energy losses in networks decrease significantly with increasing voltage, transformers are installed immediately after the generators, increasing the voltage to 35, 110, 220, 500 kV and more. Transformers are installed on outdoors. Part of the electrical energy is spent on the power plant’s own needs. Connection and disconnection of power transmission lines extending to substations and consumers is carried out on open or closed switchgear devices (ORU, ZRU), equipped with switches capable of connecting and breaking a high-voltage electrical circuit without the formation of an electric arc.

The technical water supply system supplies a large amount of cold water to cool the turbine condensers. Systems are divided into direct-flow, circulating and mixed. In once-through systems, water is pumped from a natural source (usually a river) and discharged back after passing through a condenser. In this case, the water heats up by approximately 8-12 °C, which in some cases changes the biological state of reservoirs. In recirculating systems, water circulates under the influence of circulation pumps and is cooled by air. Cooling can be carried out on the surface of cooling reservoirs or in artificial structures: splash ponds or cooling towers.

In low-water areas, instead of a technical water supply system, air-condensation systems (dry cooling towers) are used, which are an air radiator with natural or artificial draft. This decision is usually forced, since they are more expensive and less efficient in terms of cooling.

The chemical water treatment system provides chemical purification and deep desalination of water entering the steam boilers and steam turbines, to avoid deposits on internal surfaces equipment. Typically, filters, tanks and reagent facilities for water treatment are located in the auxiliary building of the IES. In addition, at thermal power plants, multi-stage systems are created for treating wastewater contaminated with petroleum products, oils, equipment washing and rinsing water, storm and melt runoff.

Environmental impact

Impact on the atmosphere. When burning fuel, a large amount of oxygen is consumed, and a significant amount of combustion products is also released, such as fly ash, gaseous sulfur oxides of nitrogen, some of which have high chemical activity.

Impact on the hydrosphere. Primarily the discharge of water from turbine condensers, as well as industrial wastewater.

Impact on the lithosphere. Disposal of large masses of ash requires a lot of space. These pollution are reduced by using ash and slag as building materials.

Current state

Currently in the Russian Federation there are standard power plants with a capacity of 1000-1200, 2400, 3600 MW and several unique ones; units of 150, 200, 300, 500, 800 and 1200 MW are used. Among them are the following state district power plants (part of OGK):

Verkhnetagilskaya GRES - 1500 MW;

Iriklinskaya GRES - 2430 MW;

Kashirskaya GRES - 1910 MW;

Nizhnevartovskaya GRES - 1600 MW;

Permskaya GRES - 2400 MW;

Urengoyskaya GRES - 24 MW.

Pskovskaya GRES - 645 MW;

Serovskaya GRES - 600 MW;

Stavropol State District Power Plant - 2400 MW;

Surgutskaya GRES-1 - 3280 MW;

Troitskaya GRES - 2060 MW.

Gusinoozerskaya GRES - 1100 MW;

Kostroma State District Power Plant - 3600 MW;

Pechora State District Power Plant - 1060 MW;

Kharanorskaya GRES - 430 MW;

Cherepetskaya GRES - 1285 MW;

Yuzhnouralskaya GRES - 882 MW.

Berezovskaya GRES - 1500 MW;

Smolenskaya GRES - 630 MW;

Surgutskaya GRES-2 - 4800 MW;

Shaturskaya GRES - 1100 MW;

Yaivinskaya GRES - 600 MW.

Konakovskaya GRES - 2400 MW;

Nevinnomysskaya GRES - 1270 MW;

Reftinskaya GRES - 3800 MW;

Sredneuralskaya GRES - 1180 MW.

Kirishskaya GRES - 2100 MW;

Krasnoyarskaya GRES-2 - 1250 MW;

Novocherkasskaya GRES - 2400 MW;

Ryazanskaya GRES (units No. 1-6 - 2650 MW and block No. 7 (the former GRES-24, which was included in the Ryazanskaya GRES - 310 MW) - 2960 MW;

Cherepovetskaya GRES - 630 MW.

Verkhnetagilskaya GRES

Verkhnetagilskaya GRES is a thermal power plant in Verkhny Tagil ( Sverdlovsk region), working as part of OGK-1. In service since May 29, 1956.

The station includes 11 power units with an electrical capacity of 1,497 MW and a thermal capacity of 500 Gcal/h. Station fuel: Natural gas (77%), coal(23%). The number of personnel is 1119 people.

Construction of the station with a design capacity of 1600 MW began in 1951. The purpose of the construction was to provide thermal and electrical energy to the Novouralsk Electrochemical Plant. In 1964, the power plant reached its design capacity.

In order to improve the heat supply to the cities of Verkhny Tagil and Novouralsk, the following stations were built:

Four condensing turbine units K-100-90 (VK-100-5) LMZ were replaced with heating turbines T-88/100-90/2.5.

On TG-2,3,4 network heaters of the PSG-2300-8-11 type are installed to heat network water in the heat supply circuit of Novouralsk.

Network heaters are installed on TG-1.4 for heat supply to Verkhny Tagil and the industrial site.

All work was carried out according to the project of the Central Clinical Hospital.

On the night of January 3-4, 2008, an accident occurred at Surgutskaya GRES-2: a partial collapse of the roof over the sixth power unit with a capacity of 800 MW led to the shutdown of two power units. The situation was complicated by the fact that another power unit (No. 5) was under repair: As a result, power units No. 4, 5, 6 were stopped. This accident was localized by January 8th. All this time, the state district power station worked in a particularly intense mode.

It is planned to build two new power units (fuel - Natural gas) by 2010 and 2013, respectively.

There is a problem of emissions into the environment at GRES. OGK-1 signed a contract with the Energy Engineering Center of the Urals for 3.068 million rubles, which provides for the development of a project for the reconstruction of the boiler at the Verkhnetagilskaya State District Power Plant, which will lead to a reduction in emissions to comply with ELV standards.

Kashirskaya GRES

Kashirskaya State District Power Plant named after G. M. Krzhizhanovsky in the city of Kashira, Moscow region, on the banks of the Oka.

A historical station, built under the personal supervision of V.I. Lenin according to the GOELRO plan. At the time of commissioning, the 12 MW station was the second largest power plant in Europe.

The station was built according to the GOELRO plan, construction was carried out under the personal supervision of V.I. Lenin. It was built in 1919-1922, for construction on the site of the village of Ternovo, the workers' settlement of Novokashirsk was erected. Launched on June 4, 1922, it became one of the first Soviet regional thermal power plants.

Pskovskaya GRES

Pskovskaya GRES is a state-owned regional power plant, located 4.5 kilometers from the urban-type settlement of Dedovichi, the regional center of the Pskov region, on the left bank of the Shelon River. Since 2006, it has been a branch of OJSC OGK-2.

High-voltage power lines connect the Pskov State District Power Plant with Belarus, Latvia and Lithuania. The parent organization considers this an advantage: there is an energy export channel that is actively used.

The installed capacity of the GRES is 430 MW, it includes two highly maneuverable power units of 215 MW each. These power units were built and put into operation in 1993 and 1996. Original advantage The first stage included the construction of three power units.

The main type of fuel is Natural gas, it enters the station through a branch of the main export gas pipeline. The power units were originally designed to operate on milled peat; they were reconstructed according to the VTI project for combustion Natural gas.

The cost of electricity for own needs is 6.1%.

Stavropol State District Power Plant

Stavropol State District Power Plant is a thermal power plant of the Russian Federation. Located in the city of Solnechnodolsk, Stavropol Territory.

Loading the power plant allows for the export of electricity abroad: to Georgia and Azerbaijan. This ensures the maintenance of flows in the system-forming electrical network of the United Energy System of the South at acceptable levels.

Part of the Wholesale Generating Company organizations No. 2 (JSC OGK-2).

The cost of electricity for the station’s own needs is 3.47%.

The main fuel of the station is Natural gas, but the station can use fuel oil as a reserve and emergency fuel. Fuel balance as of 2008: gas - 97%, fuel oil - 3%.

Smolenskaya GRES

Smolenskaya GRES is a thermal power plant of the Russian Federation. Part of the Wholesale Generating Company companies No. 4 (JSC OGK-4) since 2006.

On January 12, 1978, the first unit of the state district power station was put into operation, the design of which began in 1965, and construction in 1970. The station is located in the village of Ozerny, Dukhovshchinsky district, Smolensk region. Initially, it was intended to use peat as fuel, but due to the delay in the construction of peat mining enterprises, other types of fuel were used (Moscow region coal, Inta coal, shale, Khakass coal). A total of 14 types of fuel were changed. Since 1985 it has been finally established that energy will be obtained from Natural gas and coal.

The current installed capacity of the state district power plant is 630 MW.

Sources

Ryzhkin V. Ya. Thermal power plants. Ed. V. Ya. Girshfeld. Textbook for universities. 3rd ed., revised. and additional - M.: Energoatomizdat, 1987. - 328 p.

http://ru.wikipedia.org/

Investor Encyclopedia. 2013 .

Synonyms: Dictionary of synonyms

thermal power plant- — EN heat and power station Power station which produces both electricity and hot water for the local population. A CHP (Combined Heat and Power Station) plant may operate on almost … Technical Translator's Guide

thermal power plant- šiluminė elektrinė statusas T sritis fizika atitikmenys: engl. heat power plant; steam power plant vok. Wärmekraftwerk, n rus. thermal power plant, f; thermal power plant, f pranc. centrale électrothermique, f; centrale thermique, f; usine… … Fizikos terminų žodynas

thermal power plant- thermal power plant, thermal power plant, thermal power plant, thermal power plant, thermal power plant, thermal power plant, thermal power plant, thermal power plant, thermal power plant, thermal power plant, thermal power plant,... ... Forms of words - and; and. An enterprise that produces electrical energy and heat... Encyclopedic Dictionary

Electricity is produced at power plants by using the energy hidden in various natural resources. As can be seen from table. 1.2 this occurs mainly at thermal power plants (TPPs) and nuclear power plants (NPPs) operating according to the thermal cycle.

Types of thermal power plants

Based on the type of energy generated and released, thermal power plants are divided into two main types: condensing power plants (CHPs), intended only for the production of electricity, and heating plants, or combined heat and power plants (CHPs). Condensing power plants operating on fossil fuels are built near the places of its production, and combined heat and power plants are located near heat consumers - industrial enterprises and residential areas. CHP plants also operate on fossil fuels, but unlike CPPs, they generate both electrical and thermal energy in the form of hot water and steam for production and heating purposes. The main types of fuel of these power plants include: solid - hard coal, anthracite, semi-anthracite, brown coal, peat, shale; liquid - fuel oil and gaseous - natural, coke, blast furnace, etc. gas.

Table 1.2. Electricity generation in the world

Indicator			2010 (forecast)
Share of total output by power plants, % NPP Thermal power plant on gas TPP on fuel oil
Electricity generation by region, % Western Europe Eastern Europe Asia and Australia America Middle East and Africa
Installed capacity of power plants in the world (total), GW Including, % NPP Thermal power plant on gas TPP on fuel oil Thermal power plants using coal and other types of fuel Hydroelectric power stations and power plants using other renewable types of fuel
Electricity generation (total), billion kWh

Nuclear power plants, predominantly of the condensing type, use the energy of nuclear fuel.

Depending on the type of thermal power plant for driving an electric generator, power plants are divided into steam turbine (STU), gas turbine (GTU), combined cycle (CCG) and power plants with internal combustion engines (ICE).

Depending on the duration of work TPP throughout the year by covering energy load graphs, characterized by the number of hours of use installed capacityτ at st, power plants are usually classified into: basic (τ at st > 6000 h/year); half-peak (τ at station = 2000 – 5000 h/year); peak (τ at st< 2000 ч/год).

Basic power plants are those that carry the maximum possible constant load for most of the year. In the global energy industry, nuclear power plants, highly economical thermal power plants, and thermal power plants are used as base plants when operating according to a thermal schedule. Peak loads are covered by hydroelectric power plants, pumped storage power plants, gas turbine plants, which have maneuverability and mobility, i.e. quick start and stop. Peaking power plants are turned on at the hours when it is necessary to cover the peak part of the daily electrical load schedule. Half-peak power plants, when the total electrical load decreases, are either transferred to reduced power or put into reserve.

By technological structure Thermal power plants are divided into block and non-block. With a block diagram, the main and auxiliary equipment of a steam turbine plant does not have technological connections with the equipment of another installation of the power plant. For fossil fuel power plants, steam is supplied to each turbine from one or two boilers connected to it. With a non-block TPP scheme, steam from all boilers enters a common main and from there is distributed to individual turbines.

At condensing power plants that are part of large power systems, only block systems with intermediate superheating of steam are used. Non-block circuits with cross-coupling of steam and water are used without intermediate overheating.

Operating principle and main energy characteristics of thermal power plants

Electricity at power plants is produced by using energy hidden in various natural resources (coal, gas, oil, fuel oil, uranium, etc.), according to sufficient simple principle, implementing energy conversion technology. General scheme Thermal power plant (see Fig. 1.1) reflects the sequence of such conversion of some types of energy into others and the use of the working fluid (water, steam) in the cycle of a thermal power plant. The fuel (in this case coal) burns in the boiler, heats the water and turns it into steam. The steam is supplied to turbines, which convert the thermal energy of the steam into mechanical energy and drive generators that produce electricity (see section 4.1).

A modern thermal power plant is a complex enterprise that includes a large number of various equipment. The composition of the power plant equipment depends on the selected thermal circuit, the type of fuel used and the type of water supply system.

The main equipment of the power plant includes: boiler and turbine units with an electric generator and a condenser. These units are standardized in terms of power, steam parameters, productivity, voltage and current, etc. The type and quantity of the main equipment of a thermal power plant correspond to the specified power and the intended operating mode. There is also auxiliary equipment used to supply heat to consumers and use turbine steam to heat boiler feedwater and meet the power plant’s own needs. This includes equipment for fuel supply systems, deaeration and feed installations, condensation installations, heating plants (for thermal power plants), technical water supply systems, oil supply systems, regenerative heating of feed water, chemical water treatment, distribution and transmission of electricity (see section 4).

All steam turbine plants use regenerative heating of feed water, which significantly increases the thermal and overall efficiency of the power plant, since in circuits with regenerative heating, the steam flows removed from the turbine to the regenerative heaters perform work without losses in the cold source (condenser). At the same time, for the same electric power of the turbogenerator, the steam flow in the condenser decreases and, as a result, efficiency installations are growing.

The type of steam boiler used (see section 2) depends on the type of fuel used in the power plant. For the most common fuels (fossil coal, gas, fuel oil, milling peat), boilers with a U-, T-shaped and tower layout and a combustion chamber designed in relation to a particular type of fuel are used. For fuels with low-melting ash, boilers with liquid ash removal are used. At the same time, high (up to 90%) ash collection in the firebox is achieved and abrasive wear of heating surfaces is reduced. For the same reasons, steam boilers with a four-pass arrangement are used for high-ash fuels, such as shale and coal preparation waste. Thermal power plants usually use drum or direct-flow boilers.

Turbines and electric generators are matched on a power scale. Each turbine has a specific type of generator. For block thermal condensing power plants, the power of the turbines corresponds to the power of the blocks, and the number of blocks is determined by the given power of the power plant. Modern units use 150, 200, 300, 500, 800 and 1200 MW condensing turbines with steam reheating.

Thermal power plants use turbines (see subsection 4.2) with back pressure (type P), with condensation and industrial steam extraction (type P), with condensation and one or two heating extractions (type T), as well as with condensation, industrial and heating extraction pair (PT type). PT turbines can also have one or two heating outlets. The choice of turbine type depends on the magnitude and ratio of thermal loads. If the heating load predominates, then in addition to the PT turbines, type T turbines with heating extraction can be installed, and if the industrial load predominates, type PR and R turbines with industrial extraction and back pressure can be installed.

Currently, the most widely used thermal power plants are installations with an electrical capacity of 100 and 50 MW, operating at initial parameters of 12.7 MPa, 540–560°C. For CHP major cities installations with an electrical capacity of 175–185 MW and 250 MW (with a T-250-240 turbine) were created. Installations with T-250-240 turbines are modular and operate at supercritical initial parameters (23.5 MPa, 540/540°C).

A feature of the operation of power stations in the network is that total quantity The electrical energy generated by them at each moment of time must fully correspond to the energy consumed. The main part of the power plants operates in parallel in the unified energy system, covering the total electrical load of the system, and the thermal power plant simultaneously covers the heat load of its area. There are local power plants designed to serve the area and not connected to the general power grid.

A graphical representation of the dependence of power consumption over time is called electrical load graph. Daily graphs of electrical load (Fig. 1.5) vary depending on the time of year, day of the week and are usually characterized by a minimum load at night and a maximum load during peak hours (the peak part of the graph). Along with daily charts great value have annual graphs of electrical load (Fig. 1.6), which are constructed based on data from daily graphs.

Electrical load graphs are used when planning electrical loads of power plants and systems, distributing loads between individual power plants and units, in calculations for selecting the composition of working and backup equipment, determining the required installed power and the required reserve, the number and unit power of units, when developing equipment repair plans and determining the repair reserve, etc.

When operating at full load, the power plant equipment develops its rated or as long as possible power (performance), which is the main passport characteristic of the unit. At this maximum power (performance), the unit must operate for a long time at the nominal values ​​of the main parameters. One of the main characteristics of a power plant is its installed capacity, which is defined as the sum of the rated capacities of all electric generators and heating equipment, taking into account the reserve.

The operation of the power plant is also characterized by the number of hours of use installed capacity, which depends on the mode in which the power plant operates. For power plants carrying base load, the number of hours of use of installed capacity is 6000–7500 h/year, and for those operating in peak load coverage mode – less than 2000–3000 h/year.

The load at which the unit operates with the greatest efficiency is called the economic load. The rated long-term load can be equal to the economic load. Sometimes it is possible to operate equipment for a short time with a load 10–20% higher than the rated load at lower efficiency. If the power plant equipment operates stably with the design load at the nominal values ​​of the main parameters or when they change within acceptable limits, then this mode is called stationary.

Operating modes with steady loads, but different from the design ones, or with unsteady loads are called non-stationary or variable modes. In variable modes, some parameters remain unchanged and have nominal values, while others change within certain acceptable limits. Thus, at partial load of the unit, the pressure and temperature of the steam in front of the turbine can remain nominal, while the vacuum in the condenser and the steam parameters in the extractions will change in proportion to the load. Non-stationary modes are also possible, when all the main parameters change. Such modes occur, for example, when starting and stopping equipment, dumping and increasing the load on a turbogenerator, when operating on sliding parameters and are called non-stationary.

The thermal load of the power plant is used for technological processes and industrial installations, for heating and ventilation of industrial, residential and public buildings, air conditioning and domestic needs. For production purposes, steam pressure of 0.15 to 1.6 MPa is usually required. However, in order to reduce losses during transportation and avoid the need for continuous drainage of water from communications, steam is released from the power plant somewhat overheated. The thermal power plant usually supplies hot water with a temperature of 70 to 180°C for heating, ventilation and domestic needs.

The heat load, determined by the heat consumption for production processes and domestic needs (hot water supply), depends on the outside air temperature. In the conditions of Ukraine in summer, this load (as well as electrical) is less than in winter. Industrial and domestic heat loads change during the day, in addition, the average daily heat load of the power plant, spent on domestic needs, changes on weekdays and weekends. Typical graphs of changes in the daily heat load of industrial enterprises and hot water supply to a residential area are shown in Figures 1.7 and 1.8.

The operating efficiency of thermal power plants is characterized by various technical and economic indicators, some of which assess the perfection of thermal processes (efficiency, heat and fuel consumption), while others characterize the conditions in which the thermal power plant operates. For example, in Fig. 1.9 (a,b) shows approximate heat balances of thermal power plants and CPPs.

As can be seen from the figures, the combined generation of electrical and thermal energy provides a significant increase in the thermal efficiency of power plants due to a reduction in heat losses in turbine condensers.

The most important and complete indicators of the operation of thermal power plants are the cost of electricity and heat.

Thermal power plants have both advantages and disadvantages compared to other types of power plants. The following advantages of TPP can be indicated:

• relatively free territorial distribution associated with the wide distribution of fuel resources;
• the ability (unlike hydroelectric power plants) to generate energy without seasonal power fluctuations;
• the area of ​​alienation and withdrawal from economic circulation of land for the construction and operation of thermal power plants is, as a rule, much smaller than that required for nuclear power plants and hydroelectric power plants;
• Thermal power plants are built much faster than hydroelectric power plants or nuclear power plants, and their specific cost per unit of installed capacity is lower compared to nuclear power plants.
• At the same time, thermal power plants have major disadvantages:
• the operation of thermal power plants usually requires much more personnel than hydroelectric power plants, which is associated with the maintenance of a very large-scale fuel cycle;
• the operation of thermal power plants depends on the supply of fuel resources (coal, fuel oil, gas, peat, oil shale);
• variability of operating modes of thermal power plants reduces efficiency, increases fuel consumption and leads to increased wear and tear of equipment;
• existing thermal power plants are characterized by relatively low efficiency. (mostly up to 40%);
• Thermal power plants have a direct and adverse impact on the environment and are not environmentally friendly sources of electricity.
• The greatest damage to the environment of the surrounding regions is caused by power plants burning coal, especially high-ash coal. Among thermal power plants, the “cleanest” ones are those that use natural gas in their technological process.

According to experts, thermal power plants around the world annually emit about 200–250 million tons of ash, more than 60 million tons of sulfur dioxide, large amounts of nitrogen oxides and carbon dioxide (causing the so-called greenhouse effect and leading to long-term global climate change), into the atmosphere. absorbing large amounts of oxygen. In addition, it has now been established that the excess radiation background around thermal power plants operating on coal is, on average, 100 times higher in the world than near nuclear power plants of the same power (coal almost always contains uranium, thorium and a radioactive isotope of carbon as trace impurities ). However, well-developed technologies for the construction, equipment and operation of thermal power plants, as well as the lower cost of their construction, lead to the fact that thermal power plants account for the bulk of global electricity production. For this reason, much attention is paid to improving TPP technologies and reducing their negative impact on the environment around the world (see section 6).