Basic principles of operation of the electrical power plant. Types and types of modern thermal power plants (TES)

An electrical power plant is a power plant that converts natural energy into electrical energy. The most common are thermal power plants (TPPs), which use thermal energy released by burning organic fuel (solid, liquid and gaseous).

Thermal power plants generate about 76% of the electricity produced on our planet. This is due to the presence of fossil fuels in almost all areas of our planet; the possibility of transporting organic fuel from the extraction site to a power plant located near energy consumers; technical progress at thermal power plants, ensuring the construction of thermal power plants with high power; the possibility of using waste heat from the working fluid and supplying consumers, in addition to electrical energy, also thermal energy (with steam or hot water) and so on.

A high technical level of energy can only be ensured with a harmonious structure of generating capacities: the energy system must include nuclear power plants that generate cheap electricity, but have serious restrictions on the range and rate of load change, and thermal power plants that supply heat and electricity, the amount of which depends on the demand for energy. heat, and powerful steam turbine power units operating on heavy fuels, and mobile autonomous gas turbine units that cover short-term load peaks.

1.1 Types of electrical power plants and their features.

In Fig. 1 presents the classification of thermal power plants using fossil fuels.

Fig.1. Types of thermal power plants using fossil fuels.

Fig.2 Schematic thermal diagram of thermal power plant

1 – steam boiler; 2 – turbine; 3 – electric generator; 4 – capacitor; 5 – condensate pump; 6 – low pressure heaters; 7 – deaerator; 8 – feed pump; 9 – high pressure heaters; 10 – drainage pump.

A thermal power plant is a complex of equipment and devices that convert fuel energy into electrical and (in general) thermal energy.

Thermal power plants are characterized by great diversity and can be classified according to various criteria.

Based on their purpose and type of energy supplied, power plants are divided into regional and industrial.

District power plants are independent public power plants that serve all types of consumers in the region (industrial enterprises, transport, population, etc.). District condensing power plants, which generate mainly electricity, often retain their historical name - GRES (state district power plants). District power plants that produce electrical and thermal energy (in the form of steam or hot water), are called combined heat and power plants (CHP). As a rule, state district power plants and district thermal power plants have a capacity of more than 1 million kW.

Industrial power plants are power plants that supply thermal and electrical energy to specific production enterprises or their complex, for example a chemical production plant. Industrial power plants are part of the industrial enterprises they serve. Their power is determined by the needs of industrial enterprises for heat and electrical energy and, as a rule, it is significantly less than regional thermal power plants. Often industrial power plants operate on the general electrical network, but are not subordinate to the power system dispatcher.

Based on the type of fuel used, thermal power plants are divided into power plants operating on fossil fuels and nuclear fuel.

Condensing power plants operating on fossil fuels, at a time when there were no nuclear power plants (NPPs), were historically called thermal power plants (TES - thermal power plant). It is in this sense that this term will be used below, although thermal power plants, nuclear power plants, gas turbine power plants (GTPP), and combined cycle power plants (CGPP) are also thermal power plants operating on the principle of converting thermal energy into electrical energy.

Gaseous, liquid and solid fuels are used as organic fuel for thermal power plants. Most thermal power plants in Russia, especially in the European part, consume natural gas as the main fuel, and fuel oil as a backup fuel, using the latter due to its high cost only in extreme cases; Such thermal power plants are called gas-oil power plants. In many regions, mainly in the Asian part of Russia, the main fuel is thermal coal - low-calorie coal or waste from the extraction of high-calorie coal (anthracite coal - ASh). Since before combustion such coals are ground in special mills to a dusty state, such thermal power plants are called pulverized coal.

Based on the type of thermal power plants used at thermal power plants to convert thermal energy into mechanical energy of rotation of the rotors of turbine units, steam turbine, gas turbine and combined cycle power plants are distinguished.

The basis of steam turbine power plants are steam turbine units (STU), which use the most complex, most powerful and extremely advanced energy machine - a steam turbine - to convert thermal energy into mechanical energy. PTU is the main element of thermal power plants, combined heat and power plants and nuclear power plants.

STPs 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. STUs equipped with heating turbines and releasing the heat of exhaust steam to industrial or municipal consumers are called combined heat and power plants (CHP).

Gas turbine thermal power plants (GTPPs) are equipped with gas turbine units (GTUs) running on gaseous or, in extreme cases, liquid (diesel) fuel. Since the temperature of the gases behind the gas turbine plant is quite high, they can be used to supply thermal energy to external consumers. Such power plants are called GTU-CHP. Currently, in Russia there is one gas turbine power plant (GRES-3 named after Klasson, Elektrogorsk, Moscow region) with a capacity of 600 MW and one gas turbine cogeneration plant (in the city of Elektrostal, Moscow region).

A traditional modern gas turbine unit (GTU) is a combination of an air compressor, a combustion chamber and a gas turbine, as well as auxiliary systems that ensure its operation. The combination of a gas turbine unit and an electric generator is called a gas turbine unit.

Combined-cycle thermal power plants are equipped with combined cycle gas units (CCGs), which are a combination of gas turbines and steam turbines, which allows for high efficiency. CCGT-CHP plants can be designed as condensing plants (CCP-CHP) and with thermal energy supply (CCP-CHP). Currently, four new CCGT-CHP plants are operating in Russia (North-West CHPP of St. Petersburg, Kaliningrad, CHPP-27 of Mosenergo OJSC and Sochinskaya), and a cogeneration CCGT plant has also been built at the Tyumen CHPP. In 2007, the Ivanovo CCGT-KES was put into operation.

Modular thermal power plants consist of separate, usually of the same type, power plants - power units. In the power unit, each boiler supplies steam only to its turbine, from which it returns after condensation only to its boiler. All powerful state district power plants and thermal power plants, which have the so-called intermediate superheating of steam, are built according to the block scheme. The operation of boilers and turbines at thermal power plants with cross connections is ensured differently: all boilers of the thermal power plant supply steam to one common steam line (collector) and all steam turbines of the thermal power plant are powered from it. According to this scheme, CESs without intermediate overheating and almost all CHP plants with subcritical initial steam parameters are built.

Based on the level of initial pressure, thermal power plants of subcritical pressure, supercritical pressure (SCP) and supersupercritical parameters (SSCP) are distinguished.

The critical pressure is 22.1 MPa (225.6 at). In the Russian heat and power industry, the initial parameters are standardized: thermal power plants and combined heat and power plants are built for subcritical pressure of 8.8 and 12.8 MPa (90 and 130 atm), and for SKD - 23.5 MPa (240 atm). For technical reasons, thermal power plants with supercritical parameters are replenished with intermediate overheating and according to a block diagram. Supersupercritical parameters conventionally include pressure more than 24 MPa (up to 35 MPa) and temperature more than 5600C (up to 6200C), the use of which requires new materials and new equipment designs. Often thermal power plants or thermal power plants at different levels parameters are built in several stages - queues, the parameters of which increase with the introduction of each new queue.

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 shops 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’s personnel (housing facilities, child care 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 managment 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, a 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 - personnel 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 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 workshop organizational structure management . 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, e.g. major renovation 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. At large number Hydroelectric power plants included in the cascade use a preliminary consolidation of stations located closest to each other, headed by the head of the hydroelectric power station group. Each group independently carries out operational maintenance, including routine repairs of equipment and structures.

ORGANIZATIONAL AND PRODUCTION STRUCTURE OF THERMAL POWER PLANTS (TPP)

Depending on the power of the equipment and the schemes of technological connections between the stages of production at modern thermal power plants, they distinguish between workshop, non-shop and block-shop organizational and production structures.

Shop organizational and production structure provides for the division of technological equipment and the territory of thermal power plants into separate areas and assigning them to specialized units - workshops, laboratories. In this case, the main structural unit is the workshop. Depending on their participation in production, workshops are divided into main and auxiliary. In addition, thermal power plants can also include non-industrial farms (housing and subsidiary farms, kindergartens, holiday homes, sanatoriums, etc.).

Main workshops are directly involved in energy production. These include fuel and transport, boiler, turbine, electrical and chemical shops.

The fuel transport workshop includes railway and fuel supply sections with a fuel warehouse. This workshop is organized at power plants that burn solid fuel or fuel oil when it is delivered by rail.

The boiler shop includes areas for supplying liquid or gaseous fuel, dust preparation, and ash removal.

The turbine shop includes: heating department, central pumping station and water management.

With two workshops production structure, as well as on large thermal power plants The boiler and turbine shops are combined into a single boiler and turbine shop (BTS).

The electrical workshop is in charge of: all electrical equipment of thermal power plants, an electrical laboratory, an oil production facility, and an electrical repair shop.

The chemical workshop includes a chemical laboratory and chemical water treatment.

Auxiliary workshops serve the main production. These include: a centralized repair shop, a repair and construction shop, a thermal automation and communications shop.

Non-industrial farms are not directly related to energy production and serve the household needs of thermal power plant workers.

Shopless organizational and production structure provides for the specialization of divisions in performing basic production functions: operation of equipment, its repair maintenance, technological control. This leads to the creation of production services instead of workshops: operation, repairs, control and improvement of equipment. In turn, production services are divided into specialized areas.

Creation block-shop organizational and production structure due to the emergence of complex energy units-blocks. The unit's equipment carries out several phases of the energy process - burning fuel in a steam generator, generating electricity in a turbogenerator, and sometimes converting it in a transformer. In contrast to the workshop structure, the main production unit of a power plant in a block-shop structure is the blocks. They are included in the CTC, which are engaged in the centralized operation of the main and auxiliary equipment of boiler and turbine units. The block-shop structure provides for the preservation of the main and auxiliary workshops that take place in the workshop structure, for example, the fuel and transport workshop (FTS), chemical, etc.

All types of organizational and production structure provide for production management on the basis of unity of command. At each thermal power plant there is administrative, economic, production, technical and operational dispatch management.

The administrative and economic head of the thermal power plant is the director, the technical manager is the chief engineer. Operational dispatch control is carried out by the duty engineer of the power plant. In operational terms, he is subordinate to the duty dispatcher of the EPS.

The name and number of structural divisions, and the need to introduce individual positions are determined depending on the standard number of industrial production personnel of the power plant.

The indicated technological, organizational and economic features of electric power production affect the content and tasks of managing the activities of energy enterprises and associations.

The main requirement for the electric power industry is a reliable and uninterrupted power supply to consumers and coverage of the required load schedule. This requirement is transformed into specific indicators that evaluate the participation of the power plant and network enterprises in the implementation of the production program of energy associations.

The power plant is ready to bear the load, which is set by the dispatch schedule. For network enterprises, a repair schedule for equipment and structures is established. The plan also specifies other technical and economic indicators: specific fuel consumption at power plants, reduction of energy losses in networks, financial indicators. However, the production program of energy enterprises cannot be strictly determined by the volume of production or supply of electrical energy and heat. This is impractical due to the exceptional dynamics of energy consumption and, accordingly, energy production.

However, the volume of energy production is an important calculation indicator that determines the level of many other indicators (for example, cost) and the results of economic activities.

Gilev Alexander

Advantages of TPP:

Disadvantages of TPP:

For example :

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COMPARATIVE CHARACTERISTICS OF TPP AND NPP FROM THE POINT OF VIEW OF ENVIRONMENTAL PROBLEM.

Completed: Gilev Alexander, 11 “D” class, lyceum of the Federal State Budget Educational Institution of Higher Professional Education "Dalrybvtuz"

Scientific adviser:Kurnosenko Marina Vladimirovna, teacher of higher physics qualification category, lyceumFSBEI HPE "Dalrybvtuz"

Thermal power plant (TPP), a power plant that generates electrical energy as a result of the conversion of thermal energy released during the combustion of fossil fuels.

What fuel do thermal power plants operate on?!

Coal: On average, burning one kilogram of this type of fuel results in the release of 2.93 kg of CO2 and produces 6.67 kWh of energy or, with an efficiency of 30%, 2.0 kWh of electricity. Contains 75-97% carbon,

1.5-5.7% hydrogen, 1.5-15% oxygen, 0.5-4% sulfur, up to 1.5% nitrogen, 2-45%

volatile substances, the amount of moisture ranges from 4 to 14%. The composition of gaseous products (coke oven gas) includes benzene,

toluene, xyols, phenol, ammonia and other substances. From coke oven gas after

purification from ammonia, hydrogen sulfide and cyanide compounds extract crude

benzene, from which certain hydrocarbons and a number of other valuable

substances.

Fuel oil: Fuel oil (possibly from the Arabic mazhulat - waste), liquid product dark brown, the residue after separation of gasoline, kerosene and gas oil fractions from oil or its secondary processing products, boiling up to 350-360°C. Fuel oil is a mixture of hydrocarbons (with a molecular weight from 400 to 1000 g/mol), petroleum resins (with a molecular weight of 500-3000 or more g/mol), asphaltenes, carbenes, carboids and organic compounds containing metals (V, Ni, Fe, Mg, Na, Ca)
Gas: Main part natural gas Methane (CH4) is from 92 to 98%. Natural gas may also contain heavier hydrocarbons - homologues of methane.

Advantages and disadvantages of thermal power plants:

Advantages of TPP:

The most important advantage is the low accident rate and endurance of the equipment.
The fuel used is quite cheap.
Requires less capital investment compared to other power plants.
Can be built anywhere regardless of fuel availability. Fuel can be transported to the power plant location by rail or road transport.
Using natural gas as fuel virtually reduces emissions harmful substances into the atmosphere, which is a huge advantage over nuclear power plants.
A serious problem for nuclear power plants is their decommissioning after their resource has been exhausted; according to estimates, it can amount to up to 20% of the cost of their construction.

Disadvantages of TPP:

After all, thermal power plants that use fuel oil as fuel coal heavily pollute the environment. At thermal power plants, the total annual emissions of harmful substances, which include sulfur dioxide, nitrogen oxides, carbon oxides, hydrocarbons, aldehydes and fly ash, per 1000 MW of installed capacity range from approximately 13,000 tons per year at gas-fired thermal power plants to 165,000 at pulverized-coal thermal power plants.
Thermal power plant with a capacity of 1000 MW consumes 8 million tons of oxygen per year

For example : CHPP-2 burns half of the coal per day. This is probably the main drawback.

What if?!

What if an accident occurs at a nuclear power plant built in Primorye?
How many years will it take for the planet to recover after this?
After all, CHPP-2, which is gradually switching to gas, practically stops emissions of soot, ammonia, nitrogen, and other substances into the atmosphere!
To date, emissions from CHPP-2 have decreased by 20%.
And of course, another problem will be eliminated - the ash dump.

A little about the dangers of nuclear power plants:

It’s enough just to remember the accident at Chernobyl nuclear power plant April 26, 1986. In just 20 years, approximately 5 thousand liquidators in this group died from all causes, and this is not counting civilians... And of course, this is all official data.

Factory "MAYAK":

03/15/1953 - a self-sustaining chain reaction. The plant personnel were re-exposed;
10/13/1955 - rupture of technological equipment and destruction of parts of the building.
04/21/1957 - SCR (spontaneous chain reaction) at plant No. 20 in the collection of oxalate decantates after filtering the precipitate of enriched uranium oxalate. Six people received radiation doses ranging from 300 to 1000 rem (four women and two men), one woman died.
10/02/1958 - SCR at the plant. Experiments were carried out to determine the critical mass of enriched uranium in a cylindrical container at various concentrations of uranium in solution. The personnel violated the rules and instructions for working with nuclear material (nuclear fissile material). At the time of SCR, the personnel received radiation doses from 7600 to 13000 rem. Three people died, one person was injured radiation sickness and went blind. In the same year, I. V. Kurchatov spoke at top level and proved the need to establish a special government department on safety. LBL became such an organization.
07/28/1959 - rupture of technological equipment.
12/05/1960 - SCR at the plant. Five people were overexposed.
02/26/1962 - explosion in the sorption column, destruction of equipment.
09/07/1962 - SCR.
12/16/1965 - SCR at plant No. 20 lasted 14 hours.
12/10/1968 - SCR. The plutonium solution was poured into a cylindrical container with a dangerous geometry. One person died, another received a high dose of radiation and radiation sickness, after which his two legs and right arm were amputated.
On 02/11/1976 at a radiochemical plant, as a result of unqualified actions of personnel, an autocatalytic reaction of concentrated nitric acid with an organic liquid of complex composition developed. The device exploded, causing radioactive contamination of the repair area and the adjacent area of the plant. INEC-3 index.
10/02/1984 - explosion on the vacuum equipment of the reactor.
11/16/1990 - explosive reaction in containers with the reagent. Two people received chemical burns, one died.
07/17/1993 - An accident at the radioisotope plant of the Mayak PA with the destruction of the sorption column and the release of a small amount of α-aerosols into the environment. The radiation release was localized within the production premises of the workshop.
08/2/1993 - Failure of the pulp delivery line from a liquid radioactive waste treatment plant; an incident occurred involving the depressurization of the pipeline and the release of 2 m3 of radioactive pulp onto the surface of the earth (about 100 m2 of the surface was contaminated). The depressurization of the pipeline led to the leakage of radioactive pulp with an activity of about 0.3 Ci to the surface of the earth. The radioactive trace was localized and the contaminated soil was removed.
On December 27, 1993, an incident occurred at a radioisotope plant, where, when replacing a filter, radioactive aerosols were released into the atmosphere. The release was 0.033 Ci for α-activity and 0.36 mCi for β-activity.
02/04/1994 recorded increased emissions radioactive aerosols: by β-activity of 2-day levels, by 137Cs of daily levels, total activity 15.7 mCi.
On March 30, 1994, during the transition, daily emissions of 137Cs were exceeded by 3 times, β-activity by 1.7, and α-activity by 1.9 times.
In May 1994, a release of 10.4 mCi of β-aerosols occurred through the ventilation system of the plant building. The 137Cs emission was 83% of the control level.
On July 7, 1994, a radioactive spot with an area of several square decimeters was discovered at the instrument plant. The exposure dose rate was 500 μR/s. The stain was formed as a result of leaks from a plugged sewer.
31.08. 1994 an increased release of radionuclides into the atmospheric pipe of the radiochemical plant building was registered (238.8 mCi, including the share of 137Cs amounting to 4.36% of the annual maximum permissible release of this radionuclide). The cause of the release of radionuclides was the depressurization of VVER-440 fuel rods during the operation of cutting off the blank ends of spent fuel assemblies (spent fuel assemblies) as a result of the occurrence of an uncontrolled electric arc.
On March 24, 1995, a 19% excess of the plutonium loading norm for the apparatus was recorded, which can be considered a nuclear-hazardous incident.
On September 15, 1995, a cooling water leak was discovered at the vitrification furnace for high-level liquid radioactive waste (liquid radioactive waste). Regular operation of the furnace was stopped.
On December 21, 1995, while cutting a thermometric channel, four workers were exposed to radiation (1.69, 0.59, 0.45, 0.34 rem). The cause of the incident was a violation of technological regulations by the company's employees.
On July 24, 1995, a release of 137Cs aerosols occurred, the value of which was 0.27% of the annual MPE for the enterprise. The reason is the fire of the filter fabric.
09/14/1995 when replacing covers and lubricating stepper manipulators was registered sharp increase air pollution with α-nuclides.
On 10/22/96, the cooling water coil of one of the high-level waste storage tanks depressurized. As a result, the pipelines of the storage cooling system became contaminated. As a result of this incident, 10 department employees received radioactive exposure from 2.23×10-3 to 4.8×10-2 Sv.
On November 20, 1996, at a chemical and metallurgical plant, during work on the electrical equipment of an exhaust fan, an aerosol release of radionuclides into the atmosphere occurred, which amounted to 10% of the permitted annual release of the plant.
On August 27, 1997, in the building of the RT-1 plant, floor contamination with an area of 1 to 2 m2 was discovered in one of the premises; the dose rate of gamma radiation from the spot ranged from 40 to 200 μR/s.
On 10/06/97, an increase in the radioactive background was recorded in the assembly building of the RT-1 plant. Measurement of the exposure dose rate showed a value of up to 300 µR/s.
09/23/98 when the power of the LF-2 reactor (“Lyudmila”) increased after automatic protection was triggered permissible level capacity was exceeded by 10%. As a result, part of the fuel elements in three channels depressurized, which led to contamination of the equipment and pipelines of the primary circuit. The content of 133Xe in the release from the reactor within 10 days exceeded the annual permissible level.
On 09.09.2000 there was a power outage at PA Mayak for 1.5 hours, which could have led to an accident.
During an inspection in 2005, the prosecutor's office established a violation of the rules for handling environmentally hazardous waste from production in the period 2001-2004, which led to the dumping of several tens of millions of cubic meters of liquid radioactive waste produced by the Mayak PA into the Techa River basin. According to the deputy head of the department of the Prosecutor General's Office of the Russian Federation in the Ural Federal District, Andrei Potapov, “it has been established that the factory dam, which has long been in need of reconstruction, allows liquid radioactive waste into the reservoir, which creates serious threat For environment not only in Chelyabinsk region, but also in neighboring regions." According to the prosecutor's office, due to the activities of the Mayak plant in the floodplain of the Techa River, the level of radionuclides has increased several times over these four years. As the examination showed, the area of infection was 200 kilometers. About 12 thousand people live in the danger zone. At the same time, investigators stated that they were under pressure in connection with the investigation. to CEO PA "Mayak" Vitaly Sadovnikov was charged under Article 246 of the Criminal Code of the Russian Federation "Violation of environmental protection rules during the production of work" and parts 1 and 2 of Article 247 of the Criminal Code of the Russian Federation "Violation of rules for handling environmental hazardous substances and waste." In 2006, the criminal case against Sadovnikov was dropped due to an amnesty for the 100th anniversary of the State Duma.
Techa is a river polluted by radioactive waste discharged by the Mayak Chemical Plant, located in the Chelyabinsk region. On the banks of the river, the radioactive background was exceeded many times over. From 1946 to 1956, medium- and high-level liquid waste from the Mayak Production Association was discharged into the open Techa-Iset-Tobol river system, 6 km from the source of the Techa River. In total, 76 million m3 were discharged over these years. Wastewater with a total β-radiation activity of over 2.75 million Ci. Residents of coastal villages were exposed to both external and internal radiation. In total, 124 thousand people living in settlements on the banks of the rivers of this water system were exposed to radiation. Residents of the Techa River coast (28.1 thousand people) were exposed to the greatest amount of radiation. About 7.5 thousand people resettled from 20 settlements, received average effective equivalent doses in the range of 3 - 170 cSv. Subsequently, a cascade of reservoirs was built in the upper part of the river. Most (in terms of activity) of liquid radioactive waste was dumped into the lake. Karachay (reservoir 9) and “Old swamp”. The river's floodplain and bottom sediments are contaminated, and silt deposits in the upper part of the river are considered solid radioactive waste. Groundwater in the lake area. Karachay and the Techa cascade of reservoirs are polluted.
The accident at Mayak in 1957, also called the “Kyshtym tragedy,” is the third largest disaster in the history of nuclear energy after the Chernobyl accident and the accident at the Fukushima I nuclear power plant (INES scale).
The issue of radioactive contamination in the Chelyabinsk region was raised several times, but due to the strategic importance of the chemical plant, each time it was ignored.

FUKUSHIMA-1

The accident at the Fukushima-1 nuclear power plant is a major radiation accident (according to the Japanese officials- level 7 on the INES scale), which occurred on March 11, 2011 as a result of a powerful earthquake in Japan and the subsequent tsunami

Thermal power plants can be equipped with steam and gas turbines, with internal combustion engines. Most common thermal stations with steam turbines, which in turn are divided into: condensing (KES)— all the steam in which, with the exception of small selections for heating feedwater, is used to rotate the turbine and generate electrical energy; heating power plants- combined heat and power plants (CHP), which are the source of power for consumers of electrical and thermal energy and are located in the area of their consumption.

Condensing power plants

Condensing power plants are often called state district power plants (GRES). IES are mainly located near fuel extraction areas or reservoirs used for cooling and condensing steam exhausted from turbines.

Characteristic features of condensing power plants

for the most part, there is a significant distance from consumers of electrical energy, which necessitates the need to transmit electricity mainly at voltages of 110-750 kV;
block principle of station construction, which provides significant technical and economic advantages, consisting in increasing operational reliability and facilitating operation, and reducing the volume of construction and installation work.
Mechanisms and installations providing normal functioning stations make up its system.

IES can operate on solid (coal, peat), liquid (fuel oil, oil) fuel or gas.

Fuel supply and preparation of solid fuel consists of transporting it from warehouses to the fuel preparation system. In this system, the fuel is brought to a pulverized state for the purpose of further injecting it into the burners of the boiler furnace. To maintain the combustion process, a special fan forces air into the firebox, heated by the exhaust gases, which are sucked out of the firebox by a smoke exhauster.

Liquid fuel is supplied to the burners directly from the warehouse in a heated form by special pumps.

The preparation of gas fuel consists mainly of regulating the gas pressure before combustion. Gas from the field or storage facility is transported through a gas pipeline to the gas distribution point (GDP) of the station. Gas distribution and regulation of its parameters are carried out at the hydraulic fracturing site.

Processes in the steam-water circuit

The main steam-water circuit carries out the following processes:

The combustion of fuel in the firebox is accompanied by the release of heat, which heats the water flowing in the boiler pipes.
Water turns into steam with a pressure of 13...25 MPa at a temperature of 540..560 °C.
The steam produced in the boiler is supplied to the turbine, where it performs mechanical work - it rotates the turbine shaft. As a result, the generator rotor, located on a common shaft with the turbine, also rotates.
The steam exhausted in the turbine with a pressure of 0.003...0.005 MPa at a temperature of 120...140°C enters the condenser, where it turns into water, which is pumped into the deaerator.
In the deaerator, dissolved gases are removed, and primarily oxygen, which is dangerous due to its corrosive activity. The circulating water supply system ensures that the steam in the condenser is cooled with water from an external source (reservoir, river, artesian well). Cooled water, having a temperature not exceeding 25...36 °C at the outlet of the condenser, is discharged into the water supply system.

An interesting video about the operation of the thermal power plant can be viewed below:

To compensate for steam losses, make-up water, which has previously undergone chemical purification, is supplied to the main steam-water system by a pump.

It should be noted that for normal operation of steam-water installations, especially with supercritical steam parameters, important has the quality of the water supplied to the boiler, so the turbine condensate is passed through a system of desalting filters. The water treatment system is designed to purify make-up and condensate water and remove dissolved gases from it.

At stations using solid fuel, combustion products in the form of slag and ash are removed from the boiler furnace by a special slag and ash removal system equipped with special pumps.

When burning gas and fuel oil, such a system is not required.

There are significant energy losses at IES. Heat losses are especially high in the condenser (up to 40..50% of the total amount of heat released in the furnace), as well as with exhaust gases (up to 10%). Coefficient useful action of modern CES with high steam pressure and temperature parameters reaches 42%.

The electrical part of the IES represents a set of main electrical equipment (generators, ) and electrical equipment for auxiliary needs, including busbars, switching and other equipment with all connections made between them.

The station's generators are connected into blocks with step-up transformers without any devices between them.

In this regard, a generator voltage switchgear is not being built at the IES.

Switchgears for 110-750 kV, depending on the number of connections, voltage, transmitted power and the required level of reliability, are made according to standard electrical connection diagrams. Cross connections between blocks take place only in switchgears of the highest level or in the power system, as well as for fuel, water and steam.

In this regard, each power unit can be considered as a separate autonomous station.

To provide electricity for the station's own needs, taps are made from the generators of each block. Generator voltage is used to power powerful electric motors (200 kW or more), while a 380/220 V system is used to power lower-power motors and lighting installations. Electrical circuits for the station’s own needs may be different.

Another interesting video about the work of a thermal power plant from the inside:

Combined heat and power plants

Combined heat and power plants, being sources of combined generation of electrical and thermal energy, have a significantly larger CES (up to 75%). This is explained by this. that part of the steam exhausted in turbines is used for the needs of industrial production (technology), heating, and hot water supply.

This steam is either directly supplied for industrial and domestic needs or partially used to preheat water in special boilers (heaters), from which water is sent through the heating network to consumers of thermal energy.

The main difference between the technology of energy production in comparison with IES is the specificity of the steam-water circuit. Providing intermediate extraction of turbine steam, as well as in the method of energy delivery, according to which the main part of it is distributed at the generator voltage through a generator switchgear (GRU).

Communication with other power system stations is carried out at increased voltage through step-up transformers. During repairs or emergency shutdown of one generator, the missing power can be transferred from the power system through the same transformers.

To increase the reliability of the CHP operation, sectioning of busbars is provided.

Thus, in the event of an accident on the tires and subsequent repair of one of the sections, the second section remains in operation and provides power to consumers through the remaining energized lines.

According to such schemes, industrial ones are built with generators up to 60 MW, designed to power local loads within a radius of 10 km.

Large modern ones use generators with a power of up to 250 MW with a total station power of 500-2500 MW.

These are built outside the city limits and electricity is transmitted at a voltage of 35-220 kV, no GRU is provided, all generators are connected into blocks with step-up transformers. If it is necessary to provide power to a small local load near the block load, taps from the blocks are provided between the generator and the transformer. Combined station schemes are also possible, in which there is a main switchgear and several generators connected according to block diagrams.