Electricity is produced in power plants by using the energy hidden in various natural resources. As can be seen from table. 1.2 this happens 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 stations 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

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 Based on the coverage of energy load schedules, characterized by the number of hours of use of the installed capacity τ at the station, power plants are usually classified into: basic (τ at the station > 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 switched on during 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.

According to the 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 a fairly simple principle, implementing energy conversion technology. The general diagram of a thermal power plant (see Fig. 1.1) reflects the sequence of such conversion of one type of energy into another 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 different 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, a deaeration-feeding unit, a condensation unit, a heating unit (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, at thermal power plants, the most common are installations with an electric power of 100 and 50 MW, operating at initial parameters of 12.7 MPa, 540–560°C. For thermal power plants in large cities, installations with an electrical capacity of 175–185 MW and 250 MW (with a T-250-240 turbine) have been 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 the total amount of 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 graphs, annual graphs of electrical load (Fig. 1.6), which are constructed based on data from daily graphs, are of great importance.

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);
• variable operating modes of thermal power plants reduce efficiency, increase fuel consumption and lead 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 the world's electricity production. For this reason, much attention is being paid to improving TPP technologies and reducing their negative impact on the environment around the world (see section 6).

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 it to consumers, in addition to electrical energy, also thermal energy (with steam or hot water), etc.

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 capacity is determined by the needs of industrial enterprises for thermal and electrical energy and, as a rule, it is significantly less than that of district 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 combined heat and power plants for different levels of parameters are built in several stages - in queues, the parameters of which increase with the introduction of each new queue.

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). GRES produces 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 thus calorific value, these types are arranged as follows: peat, brown coal, 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

A couple of weeks ago, hot water disappeared from all the taps of Novodvinsk - there is no need to look for any machinations of enemies, just hydraulic tests came to Novodvinsk, a procedure necessary to prepare the city's energy and utilities for the new drinking season. Without hot water, I somehow immediately felt like a villager - pots of boiling water on the stove - wash, shave, - wash dishes in cold water, etc.

At the same time, a question arose in my head: how is hot water “made”, and how does it get into the taps in our apartments?

Of course, all the city’s energy is “powered” by the Arkhangelsk Pulp and Paper Mill, more precisely at TPP-1, where I went to find out where the hot water and heat in our apartments come from. The chief power engineer of the Arkhangelsk Pulp and Paper Mill, Andrei Borisovich Zubok, agreed to help in my search and answered many of my questions.

Here, by the way, is the desktop of the chief power engineer of the Arkhangelsk Pulp and Paper Mill - a monitor where a wide variety of data is displayed, a multi-channel telephone that rang repeatedly during our conversation, a stack of documents...

Andrey Borisovich told me how “in theory” TPP-1, the main power plant of the plant and the city, works. The very abbreviation TPP - thermal power plant - implies that the station generates not only electricity, but also heat (hot water, heating), and heat generation is perhaps even more of a priority in our cold climate.

Scheme of operation of TPP-1:


Any thermal power plant begins with the main control panel, where all the information about the processes occurring in the boilers, the operation of the turbines, etc. flows.

Here, the operation of turbines, generators and boilers is visible on numerous indicators and dials. From here the station's production process is controlled. And this process is very complex; in order to understand everything, you need to study a lot.

Well, nearby is the heart of TPP-1 - steam boilers. There are eight of them at TPP-1. These are huge structures, the height of which reaches 32 meters. It is in them that the main process of energy conversion occurs, thanks to which both electricity and hot water appear in our homes - steam production.

But in it all starts with fuel. Coal, gas, and peat can act as fuel at different power plants. At TPP-1, the main fuel is coal, which is transported here from Vorkuta by rail.

Part of it is stored, the other part goes along conveyors to the station, where the coal itself is first crushed into dust and then fed through special “dust pipes” to steam boiler furnace . To ignite the boiler, fuel oil is used, and then, as pressure and temperature increase, it is transferred to coal dust.

Externally, the boiler resembles a tangle of pipes, valves and some mechanisms. It’s hot next to the boiler, because the steam leaving the boiler has a temperature of 540 degrees.

There is also another boiler at TPP-1 - a modern Metso boiler installed several years ago with a Hybex grate. This power unit is controlled by a separate remote control.

The unit operates using innovative technology - fuel combustion in a bubble fluidized bed (Hybex). To produce steam, bark fuel (270 thousand tons per year) and sewage sludge (80 thousand tons per year) are burned here; it is brought here from wastewater treatment plants.

A modern boiler is also a huge structure, the height of which is more than 30 meters.

Or bark fuel enters the boiler through these conveyors.

And from here, after preparation, the fuel mixture goes directly into the boiler furnace.

There is an elevator in the new boiler building at TPP-1. But there are no floors in the form familiar to an ordinary city dweller - there areservice mark height- so the elevator moves from mark to mark.

More than 700 people work at the station. There is enough work for everyone - the equipment requires maintenanceand constant monitoring by staff. Working conditions at the station are difficult- high temperatures, humidity, noise, coal dust.

And here workers are preparing a site for the construction of a new boiler - its construction will begin next year.

Here the water for the boiler is prepared. In automatic mode, the water is softened in order to reduce the negative impact on the boiler and turbine blades (already at the time when the water turns into steam).

And this is the turbine hall - steam from the boilers comes here, here it spins powerful turbines (there are five in total).

Side view:

In this hall, steam works: passing through superheaters, the steam is heated to a temperature of 545 degrees and enters the turbine, where under its pressure the turbine generator rotor rotates and, accordingly, electricity is generated.

Lots of pressure gauges.

But here it is - a turbine, where the steam works and “turns” the generator. This is turbine No. 7 and, accordingly, generator No. 7.

Eighth generator and eighth turbine. The power of the generators is different, but in total they are capable of producing about 180 MW of electricity - this electricity is enough for the needs of the station itself (which is about 16%), and for the needs of the production of the Arkhangelsk Pulp and Paper Mill, and for providing “third-party consumers” (about 5% of generated energy).

The interweaving of pipes is fascinating.

Hot water for heating (network) is obtained by heating water with steam in heat exchangers (boilers). It is pumped into the network by these pumps - there are eight of them at TPP-1. Water “for heating,” by the way, is specially prepared and purified and, at the exit from the station, meets the requirements for drinking water. Theoretically, this water can be drunk, but still it is not recommended to drink it due to the presence of a large number of corrosion productsin heating pipes.

And in these towers - section of the chemical workshop of TPP-1,- water is prepared and added to the heating system, because part of the hot water is consumed - it needs to be replenished.

Then the heated water (coolant) flows through pipelines of various cross-sections, because TPP-1 heats not only the city, but also the industrial premises of the plant.

And electricity “leaves” the station throughthrough electrical distribution devices and transformers and is transmitted to the power system of the plant and the city.

Of course, there is a pipe at the station - that very “cloud factory”. There are three such pipes at TPP-1. The highest is more than 180 meters. As it turned out, the pipe is really a hollow structure where gas ducts from various boilers converge.Before entering the chimney, flue gases undergo an ash removal system. On a new boiler this happens in the electric precipitator.The effective degree of flue gas purification is 99.7%.On coal boilers, cleaning is done with water - this system is less efficient, but still most of the “emissions” are captured.

Today, renovations are in full swing at TPP-1: and if the building can be repaired at any time...

Therefore, major repairs of boilers or turbines can only be carried out in the summer during periods of reduced loads. By the way, this is precisely why “hydraulic tests” are carried out. A programmatic increase in the load on heat supply systems is necessary, firstly, to check the reliability of utility communications, and, secondly, power engineers have the opportunity to “drain” the coolant from the system and replace, for example, a section of pipe. Repair of power equipment is an expensive undertaking that requires special qualifications and permission from specialists.

Outside the plant, hot water (also known as coolant) flows through pipes - three “exits” to the city ensure uninterrupted operation of the city’s heating system. The system is closed, water constantly circulates in it. In the coldest time of the year - the temperature of the water leaving the station is 110 degrees Celsius, the coolant returns, having cooled by 20-30 degrees. In summer, the water temperature is reduced - the norm at the exit from the station is 65 degrees Celsius.

By the way, hot water and heating are turned off not at thermal power plants, but directly in houses - this is done by management companies. The thermal power plant “turns off” the water only once - after hydraulic tests, in order to make repairs. After repairs, power engineers gradually fill the system with water - the city has special mechanisms for bleeding air from the system - just like in batteries in an ordinary residential building.

The final point of hot water is the same tap in any of the city apartments, only now there is no water in it - hydraulic tests.

This is how difficult it is to “do” something without which it is difficult to imagine the life of a modern city dweller - hot water.

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What types of power plants are there?

On the threshold of the 21st century, people increasingly began to think about what would become the basis of their existence in the new era.

Energy has been and remains the main component of human life. People have gone from the first fire to nuclear power plants.

The main sources of electricity are thermal (~ 70-80%) and nuclear (10-20%).

There are types of alternative energy: the energy of the sun and wind, sea waves and hot springs, ebbs and flows.

Based on these natural resources, power plants were created: wind, tidal, geothermal, solar.

Thermal power plants.

Thermal power plants operate on the following principle: fuel is burned in the furnace of a steam boiler. The heat released during combustion evaporates the water circulating inside the pipes located in the boiler and overheats the resulting steam. The steam, expanding, rotates the turbine, which, in turn, rotates the shaft of the electric generator. The exhaust steam is then condensed; water from the condenser is returned to the boiler through the heater system.

Thermal power plants run on fossil fuels and are usually built near fuel extraction sites.

Thermal power plants use relatively cheap coal and fuel oil as fuel. But these types of fuel are irreplaceable natural resources. The main energy resources in the world today are coal (40%), oil (27%), gas (21%). These reserves, according to some estimates, will last, respectively, for 270, 50 and 70 years, and only if humanity uses them at the same rate as it does today.

Thermal power plants operate on fossil fuels and therefore they are built near the places of its production. Cheap coal and fuel oil are used as fuel. But, unfortunately, these are irreplaceable natural resources that will only last for a few decades. In addition, during the combustion of fuel, harmful substances are formed that adversely affect the environment.

Thermal power plant operating diagram

Such power plants operate on the same principle as thermal power plants, but use the energy obtained during radioactive decay for steam generation.

Enriched uranium ore is used as fuel. A nuclear reactor operates on the basis of a nuclear chain reaction, where the fission of one nucleus causes the fission of other nuclei; thus the reaction is self-sustaining.

The practical implementation of chain reactions is not as simple a task as it looks in the diagram. Neutrons released during the fission of uranium nuclei are capable of causing the fission of only nuclei of the uranium isotope with a mass number of 235, but their energy is insufficient to destroy the nuclei of a uranium isotope with a mass number of 238. In natural uranium, the share of uranium-238 is 99.3%, and the share of uranium-235 is only 0.7%.

The minimum mass of uranium in which a chain reaction can occur is called the critical mass. The critical mass for uranium-235 is several tens of kilograms. “The first nuclear reactors were slow neutron reactors.

Slow neutrons interact well with uranium-235 nuclei and are absorbed by them 500 times more efficiently than fast neutrons. Therefore, when natural uranium is irradiated with slow neutrons, most of them are absorbed not in the nuclei of uranium-238, but in the nuclei of uranium-235 and cause their fission. This means that for a chain reaction to develop in natural uranium, neutron velocities must be reduced to thermal ones. Neutrons slow down as a result of collisions with atomic nuclei of the medium in which they move. To slow down the reactor, a special substance called a moderator is used. Usually it is water or graphite.

The reactor is controlled using special control rods inserted into the reactor core. Control rods are made of boron or cadmium compounds, which absorb thermal neutrons with very high efficiency. By absorbing a significant portion of neutrons, they make it impossible for a chain reaction to develop. To start the reactor, the rods are removed from the core until the energy release reaches a predetermined level. When the power increases above the set level, automatic machines are switched on, plunging the control rods deep into the core.

Currently, scientists are working on the creation of thermonuclear power plants, the advantage of which is to provide humanity with electricity for an unlimited time. A thermonuclear power plant operates on the basis of thermonuclear fusion - the reaction of synthesis of heavy hydrogen isotopes with the formation of helium and the release of energy. The thermonuclear fusion reaction does not produce gaseous or liquid radioactive waste and does not produce plutonium, which is used to produce nuclear weapons. If we also take into account that the fuel for thermonuclear stations will be the heavy hydrogen isotope deuterium, which is obtained from simple water - half a liter of water contains fusion energy equivalent to that obtained by burning a barrel of gasoline - then the advantages of power plants based on thermonuclear reactions are become obvious.

International thermonuclear reactor ITER.

I would like to believe that the era of environmentally hazardous hydroelectric and nuclear power plants will soon end, and the time will come for new power plants - thermonuclear ones. But, despite the fact that the ITER (International Thermonuclear Reactor) project is almost ready; Despite the fact that already at the first operating experimental thermonuclear reactors a power exceeding 10 MW was obtained - the level of the first nuclear power plants, the first thermonuclear power plant will not work earlier than in twenty years, because its cost is very high. For example, the construction of ITER requires, according to the most conservative estimates, from 8 to 10 billion dollars and 10 years of work. These figures cause deep confusion among the participants in the project; the United States even withdrew from it.

Wind power plants.

The principle of operation of wind power plants is simple: the wind turns the blades of the windmill, driving the shaft of the electric generator. The generator, in turn, produces electrical energy. It turns out that wind power plants work like battery-powered toy cars, only the principle of their operation is the opposite. Instead of converting electrical energy into mechanical energy, wind energy is converted into electrical current.

To obtain wind energy, different designs are used: multi-blade “daisies”; propellers like airplane propellers with three, two, or even one blade (then it has a counterweight); vertical rotors resembling a barrel cut lengthwise and mounted on an axis; some semblance of a helicopter propeller “standing on end”: the outer ends of its blades are bent upward and connected to each other. Vertical structures are good because they catch wind from any direction. The rest have to turn with the wind.

Wind turbines are very cheap to produce, but their power is low and their operation is dependent on the weather. In addition, they are very noisy, so large installations even have to be turned off at night. In addition, wind power plants interfere with air traffic and even radio waves. The use of wind turbines causes a local weakening of the strength of air flows, which interferes with the ventilation of industrial areas and even affects the climate. Finally, their use requires huge areas much larger than for other types of electric generators.

Tidal power plants.

This type of power plant uses tidal energy to generate electricity. The first such power plant (Pauzhetskaya) with a capacity of 5 MW was built in Kamchatka. To set up a simple tidal power station (TPP), you need a pool - a dammed bay or a river mouth. The dam has culverts and turbines that drive a generator. At high tide, water flows into the pool. When the water levels in the pool and the sea are equal, the gates of the culverts are closed. With the onset of low tide, the water level in the sea decreases, and when the pressure becomes sufficient, the turbines and electric generators connected to it begin to work, and the water gradually leaves the pool.

It is considered economically feasible to build tidal power plants in areas with tidal fluctuations in sea level of at least 4 m. The design capacity of a tidal power plant depends on the nature of the tide in the area where the station is built, on the volume and area of ​​the tidal basin, and on the number of turbines installed in the dam body.

In double-acting tidal power plants, turbines operate by moving water from the sea to the basin and back. Double-acting tidal power plants are capable of generating electricity continuously for 4-5 hours with breaks of 1-2 hours four times a day. To increase the operating time of turbines, there are more complex schemes - with two, three or more pools, but the cost of such projects is very high. The disadvantage of tidal power plants is that they are built only on the shores of seas and oceans, moreover, they do not develop very much power, and the tides occur only twice a day. And even they are not environmentally friendly.

They disrupt the normal exchange of salt and fresh water and thereby the living conditions of marine flora and fauna. They also influence the climate, since they change the energy potential of sea waters, their speed and area of ​​movement. Marine heating stations, built on the temperature difference of sea water, contribute to the release of large amounts of carbon dioxide, heating and reducing the pressure of deep waters and cooling of surface waters. And these processes cannot but affect the climate, flora and fauna of the region.

Power plants of this type convert the internal heat of the Earth (energy from hot steam-water sources) into electricity.

The first geothermal power plant was built in Kamchatka. There are several schemes for generating electricity from a geothermal power plant.

Direct scheme: natural steam is directed through pipes to turbines connected to electric generators.

Indirect scheme: steam is first (before it enters the turbines) purified from gases that cause pipe destruction. Mixed scheme: untreated steam enters the turbines, and then gases that have not dissolved in it are removed from the water formed as a result of condensation.

The disadvantages of geothermal electrical installations include the possibility of local soil subsidence and the awakening of seismic activity. And the gases coming out of the ground create considerable noise in the surrounding area and may, moreover, contain toxic substances. In addition, a geothermal power plant cannot be built everywhere, because certain geological conditions are required for its construction.

Solar power plants.

Currently, solar power plants are built mainly of two types: solar power plants of the tower type and solar power plants of the distributed (modular) type.

Tower solar power plants use a central receiver with a heliostat field that provides a concentration degree of several thousand. The solar tracking system is significantly complex, as it requires rotation around two axes. The system is controlled using a computer. The working fluid in a heat engine is usually water vapor with a temperature of up to 550°C, air and other gases - up to 1000°C, low-boiling organic liquids (including freons) - up to 100°C, liquid metal coolants - up to 800°C.

The main disadvantage of tower solar power plants is their high cost and large footprint. Thus, to accommodate a solar power plant with a capacity of 100 MW, an area of ​​200 hectares is required, and for a nuclear power plant with a capacity of 1000 MW - only 50 hectares. Tower solar power plants with a capacity of up to 10 MW are unprofitable, their optimal power is 100 MW, and the tower height is 250 m.

Distribution-type (modular) solar power plants use a large number of modules, each of which includes a parabolic-cylindrical solar radiation concentrator and a receiver located at the focus of the concentrator and used to heat the working fluid supplied to the heat engine, which is connected to an electric generator. The largest solar power plant of this type was built in the USA and has a capacity of 12.5 MW.

With low power, modular solar power plants are more economical than tower ones. Modular solar power plants typically use linear solar energy concentrators with a maximum concentration ratio of about 100.

Energy from solar radiation can be converted into direct electric current through solar cells, devices made of thin films of silicon or other semiconductor materials. The advantage of photoelectric converters (PVCs) is due to the absence of moving parts, their high reliability and stability. Moreover, their service life is practically unlimited. They are lightweight, easy to maintain, and effectively use both direct and diffuse solar radiation. The modular type of design allows you to create installations of almost any capacity and makes them very promising. The disadvantage of PV cells is their high cost and low efficiency (currently almost 10-12%).

Solar batteries are still used mainly in space, and on Earth only to supply power to autonomous consumers with a power of up to 1 kW, power radio navigation and low-power electronic equipment, and drive experimental electric vehicles and aircraft. In 1988, the first global solar car rally took place in Australia. As solar panels improve, they will find application in residential buildings for autonomous power supply, i.e. heating and hot water supply, as well as for generating electricity for lighting and powering household electrical appliances.

Hydroelectric power stations.

Hydroelectric power plants convert the energy of water flow into electricity through hydraulic turbines that drive electric generators. A hydroelectric power plant has the greatest efficiency when the flow of water falls on the turbine from above. For these purposes, a dam is built to raise the water level in the river and concentrate the water pressure at the location of the turbines.

Scheme of operation of the hydroelectric power station:

The energy of moving water is converted into electricity by feeding it directly to the turbine.

When a dam is built, a reservoir is formed. Water that has flooded vast areas irreversibly changes the environment. Raising the river level by a dam can cause waterlogging, salinity, and changes in riparian vegetation and microclimate. In addition, the dam blocks the path of fish going to spawn. Fields and forests are flooded, people are evicted from their homes.

Renewable types of energy.

There are many different ideas and proposals put forward for the use of all kinds of renewable energy. Even manure can serve as a source of energy! Not only manure, but also its processed products are used as fuel. Manure is often processed together with municipal waste. The fact is that both types of biomass contain microorganisms that, under certain conditions (in particular, at a temperature of 50-60°C, without air access) decompose organic substances into biogas. This process necessarily occurs with the participation of special substances - enzymes - and is therefore called fermentation.

Animal waste recycling scheme.

The waste goes through a pipeline to a power plant, where it is subjected to biological processing in a special reactor. The resulting gas is used to generate electricity, and the waste processed by bacteria is used for fertilizer. electric fusion reactor

Power plants with internal combustion engines.

It is believed that the inventor of the internal combustion engine (ICE) is the outstanding Dutch mathematician H. Huygens. However, the engine he proposed was not built. In 1866, German scientists Langen and N. Otto created a more efficient gas engine. And in 1891, the German engineer R. Diesel built an internal combustion engine with compression ignition of the mixture. The idea and principle of operation of Rudolf Diesel's engine was stated as follows:

A working process in an internal combustion engine, characterized in that the piston in the cylinder compresses air or a mixture of some other indifferent gas (steam) with air so strongly that the resulting compression temperature significantly exceeds the ignition temperature of the fuel; in this case, the combustion of the fuel gradually introduced after the dead point occurs in such a way that there is no significant increase in pressure and temperature in the engine cylinder.

When carrying out the working process described above, a multi-stage compressor with a receiver is attached to the working cylinder. It is also possible to connect several working cylinders to each other or to cylinders for pre-compression and subsequent expansion.

A year after receiving the patent, the theoretical part of Diesel’s work was outlined by him in the brochure “The Theory and Design of a Rational Heat Engine Designed to Replace the Steam Engine and Other Currently Existing Engines.” In such an engine, Diesel believed, the temperature of the expanding gas mixture should increase not only as a result of fuel combustion, but also before the start of this process - by pre-compressing clean air in the cylinder. The “rational engine,” like Otto’s gas engines, was supposed to operate on a four-stroke cycle.

However, the latter did not suck in clean air, but a working mixture consisting of air and gaseous fuel, which did not allow, due to the possibility of premature ignition of the mixture, to achieve high compression ratios. Clean air sucked in through the Diesel cycle could be brought to any technically feasible compression ratio. If in Otto engines the mixture was ignited by an electric spark, then in a Diesel engine the hot air itself ignited the incoming fuel. Finally, Diesel planned to gradually burn the fuel as it was supplied without significantly increasing the temperature in the cylinder during the power stroke, while in the Otto engine the mixture burned quickly, almost explosively. Thus, Diesel hoped to come close to the implementation of the thermodynamic Carnot cycle.

The hundred-year history of the development of internal combustion engines, combined with the latest advances in the field of electronics and computer technology, has contributed to the creation of modern power plants with internal combustion engines.

Currently, compact mobile power plants are becoming an item of everyday use. Home power plants running on gasoline and diesel fuel allow you to supply electricity to the house autonomously, without a centralized power grid, which is why they are increasingly used in cottages and dachas. Autonomous electric generators do not take up much space, and some models have an automatic start system with switching of the consumer to the power plant (autostart). In this case, approximately 20-50 seconds after the power supply is disconnected, all turned on household electrical appliances can be “revitalized” again by the home power plant, and when the centralized power supply is restored, it will automatically turn off with an interruption in the supply of voltage to the network for only 2-5 seconds.

Components of a diesel/gasoline electric unit.

A home power plant consists of an internal combustion engine (carburetor or diesel) driving a generator that produces electricity at 220 or 380 V at a frequency of 50 Hz. Synchronous type generators are most often used, although they can also be asynchronous. Some models of electric generators provide a three-phase voltage of 380 or 400 V, as well as a constant voltage of 12 V for recharging the car battery. Power plants with a carburetor engine run on gasoline (usually AI-92), and those with a diesel engine run on diesel fuel. The simplest engine used is a single-cylinder, air-cooled two-stroke, and the most complex is a twelve-cylinder, four-stroke, water-cooled diesel engine.

Power plants differ in the values ​​of operating parameters: power, resource, efficiency and a number of others.

Their power can be from 0.35 kW to 500 kW or more, but for home use it usually does not exceed 5-20 kW. It should be noted that gasoline electric generators have a power from 0.35 to 11 kW, while diesel power plants have a power from 2.5 kW and above.

Another important parameter is the resource of guaranteed trouble-free operation until the first major overhaul of the power plant, measured in engine hours. According to it, power plants can be divided into three groups - seasonal (with a resource from 500 to 1000 operating hours), robustas - only for powering household electrical appliances and power tools (with a resource from 1500 to 2500 operating hours) and long-term use (with a resource of 3000 operating hours and more). The cost of a power plant, both gasoline and diesel, increases in proportion to its resource.

The third operating parameter is fuel consumption, expressed in liters of fuel consumed per hour of continuous engine operation, or abbreviated as l/hour. Having these data, it is possible to calculate the efficiency of the power plant, which is estimated at the cost of one hour of its operation in rubles.

This article discusses a far from complete list of methods for generating electricity and, accordingly, not all types of power plants. This article will be updated as new information becomes available.

Posted on Allbest.ru

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