The impeller blades of this steam turbine are clearly visible.
A thermal power plant (CHP) uses the energy released by burning fossil fuels - coal, oil and natural gas - to convert water into steam high pressure. This steam, having a pressure of about 240 kilograms per square centimeter and a temperature of 524°C (1000°F), rotates the turbine. The turbine spins a giant magnet inside a generator, which produces electricity.
Modern thermal power plants convert about 40 percent of the heat released during fuel combustion into electricity, the rest is discharged into environment. In Europe, many thermal power plants use waste heat to heat nearby homes and businesses. Combined heat and power generation increases the energy output of the power plant by up to 80 percent.
Steam turbine plant with electric generator
A typical steam turbine contains two groups of blades. High-pressure steam coming directly from the boiler enters the flow path of the turbine and rotates the impellers with the first group of blades. The steam is then heated in the superheater and again enters the turbine flow path to rotate impellers with a second group of blades, which operate at a lower steam pressure.
Sectional view
A typical thermal power plant (CHP) generator is driven directly by a steam turbine, which rotates at 3,000 revolutions per minute. In generators of this type, the magnet, also called the rotor, rotates, but the windings (stator) are stationary. The cooling system prevents the generator from overheating.
Power generation using steam
At a thermal power plant, fuel burns in a boiler, producing a high-temperature flame. The water passes through the tubes through the flame, is heated and turns into high-pressure steam. The steam spins a turbine, producing mechanical energy, which a generator converts into electricity. After leaving the turbine, the steam enters the condenser, where it washes the tubes with cold running water, and as a result turns into a liquid again.
Oil, coal or gas boiler
Inside the boiler
The boiler is filled with intricately curved tubes through which heated water passes. The complex configuration of the tubes allows you to significantly increase the amount of heat transferred to the water and, as a result, produce much more steam.
At thermal power plants, people receive almost all the energy they need on the planet. People have learned to receive electricity otherwise, but still not accepted alternative options. Even if it is unprofitable for them to use fuel, they do not refuse it.
What is the secret of thermal power plants?
Thermal power plants It is no coincidence that they remain indispensable. Their turbine produces energy in the simplest way, using combustion. Due to this, it is possible to minimize construction costs, which are considered completely justified. There are such objects in all countries of the world, so one should not be surprised at the spread.
Operating principle of thermal power plants built on burning huge volumes of fuel. As a result, electricity appears, which is first accumulated and then distributed to certain regions. Thermal power plant patterns remain almost constant.
What fuel is used at the station?
Each station uses a separate fuel. It is specially supplied so that the workflow is not disrupted. This point remains one of the problematic ones, as transportation costs arise. What types of equipment does it use?
- Coal;
- Oil shale;
- Peat;
- Fuel oil;
- Natural gas.
Thermal circuits of thermal power plants are built on a certain form fuel. Moreover, minor changes are made to them to ensure the maximum coefficient useful action. If they are not done, the main consumption will be excessive, and therefore the resulting electric current will not be justified.
Types of thermal power plants
The types of thermal power plants are an important issue. The answer to it will tell you how the necessary energy appears. Today, serious changes are gradually being made, where alternative types will be the main source, but so far their use remains inappropriate.
- Condensing (IES);
- Combined heat and power plants (CHP);
- State district power plants (GRES).
The thermal power plant will require a detailed description. The types are different, so only consideration will explain why construction of such a scale is carried out.
Condensing (IES)
Types of thermal power plants begin with condensing ones. Such thermal power plants are used exclusively for generating electricity. Most often, it accumulates without immediately spreading. The condensation method provides maximum efficiency, so similar principles are considered optimal. Today, in all countries, there are separate large-scale facilities that supply vast regions.
Nuclear plants are gradually appearing, replacing traditional fuel. Only replacement remains an expensive and time-consuming process, since working on fossil fuels differs from other methods. Moreover, shutting down a single station is impossible, because in such situations entire regions are left without valuable electricity.
Combined heat and power plants (CHP)
CHP plants are used for several purposes at once. They are primarily used to generate valuable electricity, but burning fuels also remains useful for generating heat. Due to this, cogeneration power plants continue to be used in practice.
Important feature is that such thermal power plants are superior to other types of relatively not high power. They supply specific areas, so there is no need for bulk supplies. Practice shows how beneficial such a solution is due to the laying of additional power lines. The operating principle of a modern thermal power plant is unnecessary only because of the environment.
State district power plants
General information about modern thermal power plants GRES is not noted. Gradually they remain in the background, losing their relevance. Although state-owned district power plants remain useful in terms of energy output.
Different types Thermal power plants provide support to vast regions, but their capacity is still insufficient. During the Soviet era, large-scale projects were carried out, which are now being closed. The reason was inappropriate use of fuel. Although their replacement remains problematic, since the advantages and disadvantages of modern thermal power plants are primarily noted for the large volumes of energy.
Which power plants are thermal? Their principle is based on burning fuel. They remain indispensable, although calculations are actively underway for equivalent replacement. Thermal power plants continue to prove their advantages and disadvantages in practice. Because of which their work remains necessary.
THERMAL POWER PLANTS. TPP STRUCTURE, MAIN ELEMENTS. STEAM GENERATOR. STEAM TURBINE. CAPACITOR
Classification of thermal power plants
Thermal power plant(TPP) - power plant , producing electrical energy as a result of the conversion of thermal energy released during the combustion of organic fuel.
The first thermal power plants appeared at the end of the 19th century (in 1882 - in New York, in 1883 - in St. Petersburg, in 1884 - in Berlin) and became widespread. Currently, TPP is main type of power stations. The share of electricity generated by them is: in Russia approximately 70%, in the world about 76%.
Among thermal power plants, thermal steam turbine power plants (TSPP) predominate, at which thermal energy used in a steam generator to produce high-pressure water steam that drives a steam turbine rotor connected to the rotor of an electrical generator (usually a synchronous generator) . The generator together with the turbine and exciter is called turbogenerator.In Russia, TPPP produces ~99% of the electricity generated by thermal power plants. The fuel used at such thermal power plants is coal (mainly), fuel oil, natural gas, lignite, peat, and shale.
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 (CPS). In Russia, IES is historically called the State District Electric Station, or GRES. . GRES produces about 65% of the electricity produced at thermal power plants. Their efficiency reaches 40%. The world's largest power plant, Surgutskaya GRES-2; its capacity is 4.8 GW; Reftinskaya GRES capacity is 3.8 GW.
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, respectively, about 35% of the electricity produced at thermal power plants. Thanks to more complete use of thermal energy, the efficiency of thermal power plants increases to 60 - 65%. The most powerful thermal power plants in Russia, CHPP-23 and CHPP-25 of Mosenergo, each have a capacity of 1,410 MW.
Industrial gas turbines appeared much later than steam turbines, since their manufacture required special heat-resistant structural materials. Compact and highly maneuverable gas turbine units (GTUs) were created based on gas turbines. Gas or liquid fuel is burned in the combustion chamber of a gas turbine unit; combustion products with a temperature of 750 - 900 ° C enter the gas turbine, which rotates the rotor of the electric generator. The efficiency of such thermal power plants is usually 26 - 28%, power - up to several hundred MW . GTUs are not economical due to high temperature flue gases.
Thermal power plants with gas turbine units are used mainly as backup sources of electricity to cover peaks in electrical load or to supply electricity to small settlements. They allow the power plant to operate at abruptly changing load; can stop frequently, provide quick start-up, high speed of power gain and fairly economical operation over a wide load range. As a rule, gas turbine plants are inferior to steam turbine thermal power plants in terms of specific fuel consumption and cost of electricity. The cost of construction and installation work at thermal power plants with gas turbine units is reduced by approximately half, since there is no need to build a boiler shop and pumping station. The most powerful thermal power plant with gas turbine unit GRES-3 named after. Klasson (Moscow region) has a capacity of 600 MW.
The exhaust gases of gas turbine plants have a fairly high temperature, as a result of which gas turbine plants have low efficiency. IN combined cycle plant(PGU), consisting of steam turbine and gas turbine units, the hot gases of the gas turbine are used to heat water in the steam generator. These are combined type power plants. The efficiency of thermal power plants with combined cycle gas turbine units reaches 42 - 45%. The CCGT is currently the most economical engine used to generate electricity. In addition, this is the most environmentally friendly engine, which is explained by its high efficiency. CCGT appeared a little over 20 years ago, however, now it is the most dynamic sector of the energy sector. The most powerful power units with combined cycle gas turbine units in Russia: at the South Thermal Power Plant of St. Petersburg - 300 MW and at the Nevinnomysskaya State District Power Plant - 170 MW.
Thermal power plants with gas turbine units and combined cycle gas turbine units can also supply heat to external consumers, that is, operate as a combined heat and power plant.
By technological scheme steam pipelines of thermal power plants are divided into block thermal power plants and on TPP with cross links.
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 own turbine, from which it returns after condensation only to its own 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.
According to the level of initial pressure, thermal power plants are distinguished subcritical pressure And supercritical pressure(SKD).
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). TPPs with supercritical parameters, for technical reasons, are performed with intermediate overheating and according to a block diagram.
The efficiency of thermal power plants is assessed efficiency(efficiency), which is determined by the ratio of the amount of energy released over a period of time to the expended heat contained in the burned fuel. Along with efficiency, another indicator is also used to evaluate the operation of thermal power plants - specific consumption of standard fuel(conventional fuel is fuel having a calorific value = 7000 kcal/kg = 29.33 MJ/kg). There is a connection between efficiency and conditional fuel consumption.
TPP structure
Main elements of thermal power plant (Fig. 3.1):
u boiler plant, converting the energy of chemical bonds of fuel and producing water vapor with high temperature and pressure;
u turbine (steam turbine) installation, converting the thermal energy of steam into mechanical energy of rotation of the turbine rotor;
u electric generator, ensuring the conversion of the kinetic energy of rotor rotation into electrical energy.
Figure 3.1. Main elements of thermal power plant
The heat balance of the thermal power plant is shown in Fig. 3.2.
Figure 3.2. Thermal balance of thermal power plants
The main energy loss at thermal power plants occurs due to heat transfer from steam to cooling water in the condenser; More than 50% of the heat (energy) is lost with the heat of steam.
3.3. Steam generator (boiler)
The main element of the boiler installation is steam generator, which is a U-shaped structure with gas ducts rectangular section. Most of the boiler is occupied by the firebox; its walls are lined with screens made of pipes through which the feed water. A steam generator burns fuel, turning water into steam at high pressure and temperature. For complete combustion of fuel, heated air is pumped into the boiler furnace; To generate 1 kWh of electricity, about 5 m 3 of air is required.
When fuel burns, the energy of its chemical bonds is converted into thermal and radiant energy of the torch. As a result of a chemical combustion reaction, in which fuel carbon C is converted into oxides CO and CO 2, sulfur S into oxides SO 2 and SO 3, etc., and fuel combustion products (flue gases) are formed. Cooled to a temperature of 130 - 160 O C, flue gases leave the thermal power plant through the chimney, carrying away about 10 - 15% of the energy (Fig. 3.2).
Currently the most widely used drums(Fig. 3.3, a) and once-through boilers(Fig. 3.3, b). Repeated circulation of feed water is carried out in the screens of drum boilers; steam is separated from water in a drum. In direct-flow boilers, water passes through the screen pipes only once, turning into dry saturated steam (steam in which there are no water droplets).
A) b)
Figure 3.3. Schemes of drum (a) and direct-flow (b) paragenerators
IN Lately To increase the efficiency of steam generators, coal is burned at intra-cycle gasification and in circulating fluidized bed; at the same time, efficiency increases by 2.5%.
Steam turbine
Turbine(fr. turbine from lat. turbo vortex, rotation) is a continuous heat engine, in the blade apparatus of which the potential energy of compressed and heated water vapor is converted into the kinetic energy of rotation of the rotor.
Attempts to create mechanisms similar to steam turbines were made thousands of years ago. There is a known description of a steam turbine made by Heron of Alexandria in the 1st century BC. e., the so-called "Heron turbine". However, only at the end of the 19th century, when thermodynamics, mechanical engineering and metallurgy reached a sufficient level Gustaf Laval (Sweden) and Charles Parsons (Great Britain) independently created steam turbines suitable for industry. The manufacture of an industrial turbine required a significantly higher production standard than a steam engine.
In 1883 Laval created the first working steam turbine. Its turbine was a wheel with steam supplied to its blades. He then added conical expanders to the nozzles; which significantly increased the efficiency of the turbine and turned it into a universal engine. Steam, heated to a high temperature, came from the boiler through a steam pipe to the nozzles and exited. In the nozzles the steam expanded to atmospheric pressure. Due to the increase in steam volume, a significant increase in rotation speed was obtained. Thus, the energy contained in the steam was transferred to the turbine blades. The Laval turbine was much more economical than the old steam engines.
In 1884, Parsons received a patent for multi-stage jet turbine, which he created specifically to power an electric generator. In 1885, he designed a multi-stage jet turbine (to increase the efficiency of steam energy use), which was later widely used in thermal power plants.
A steam turbine consists of two main parts: rotor with blades - the moving part of the turbine; stator with nozzles - fixed part. The fixed part is made detachable in the horizontal plane to allow removal or installation of the rotor (Fig. 3.4.)
Figure 3.4. Type of the simplest steam turbine
Based on the direction of steam flow, they are distinguished axial steam turbines, in which the steam flow moves along the axis of the turbine, and radial, the direction of steam flow in which is perpendicular, and the working blades are located parallel to the axis of rotation. In Russia and the CIS countries, only axial steam turbines are used.
According to the method of action, turbine steam is divided into: active, reactive And combined. The active turbine uses kinetic energy couple, in reactive: kinetic and potential .
Modern technologies allow you to maintain the rotation speed with an accuracy of three revolutions per minute. Steam turbines for power plants are designed for 100 thousand operating hours (up to overhaul). A steam turbine is one of the most expensive elements of a thermal power plant.
Sufficiently complete utilization of steam energy in a turbine can only be achieved by operating steam in a series of turbines located in series, which are called steps or cylinders. In multi-cylinder turbines, the rotation speed of the working disks can be reduced. Figure 3.5 shows a three-cylinder turbine (without casing). To the first cylinder - the high pressure cylinder (HPC), 4 steam is supplied through steam lines 3 directly from the boiler and therefore it has high parameters: for SKD boilers - pressure 23.5 MPa, temperature 540 ° C. At the HPC outlet, the steam pressure is 3-3 .5 MPa (30 - 35 at), and the temperature is 300 O - 340 O C.
Figure 3.5. Three-cylinder steam turbine
To reduce erosion of turbine blades (wet steam) From the HPC, relatively cold steam returns back to the boiler, into the so-called intermediate superheater; in it the steam temperature rises to the initial one (540 O C). The newly heated steam is supplied through steam lines 6 to the medium pressure cylinder (MPC) 10. After expanding the steam in the MPC to a pressure of 0.2 - 0.3 MPa (2 - 3 atm), the steam is supplied to the receiver pipes 7 using exhaust pipes, of which is sent to the low pressure cylinder (LPC) 9. The steam flow speed in the turbine elements is 50-500 m/s. The blade of the last stage of the turbine has a length of 960 mm and a mass of 12 kg.
Efficiency of heat engines and an ideal steam turbine, in particular, is determined by the expression:
,
where is the heat received by the working fluid from the heater, and is the heat given to the refrigerator. Sadi Carnot in 1824 theoretically obtained an expression for limit (maximum) efficiency value heat engine with a working fluid in the form of an ideal gas
,
where is the temperature of the heater, is the temperature of the refrigerator, i.e. steam temperatures at the turbine inlet and outlet, respectively, measured in degrees Kelvin (K). For real heat engines.
To increase turbine efficiency, lower inappropriate; this is due to additional energy consumption. Therefore, to increase efficiency, you can increase . However for modern development Technology has already reached its limit here.
Modern steam turbines are divided into: condensation And district heating. Condensing steam turbines are used to convert as much of the energy (heat) of steam as possible into mechanical energy. They work by releasing (exhausting) the spent steam into a condenser, which is maintained under a vacuum (hence the name).
Thermal power plants with condensing turbines are called condensing power stations(IES). The main end product of such power plants is electricity. Only a small part of the thermal energy is used for the power plant’s own needs and, sometimes, to supply heat to nearby settlement. Usually this is a settlement for energy workers. It has been proven that more power turbogenerator, the more economical it is, and the lower the cost of 1 kW of installed power. Therefore, high-power turbogenerators are installed at condensing power plants.
Cogeneration steam turbines are used to simultaneously produce electrical and thermal energy. But the main end product of such turbines is heat. Thermal power plants with cogeneration steam turbines are called combined heat and power plants(CHP). Cogeneration steam turbines are divided into: turbines with back pressure, with adjustable steam extraction And with selection and back pressure.
For turbines with back pressure, the entire exhaust steam is used for technological purposes(cooking, drying, heating). Electric power, developed by a turbine unit with such a steam turbine, depends on the need of the production or heating system for heating steam and changes with it. Therefore, a backpressure turbine unit usually operates in parallel with a condensing turbine or power grid, which covers the resulting electricity shortage. In turbines with extraction and back pressure, part of the steam is removed from the 1st or 2nd intermediate stages, and all exhaust steam is directed from the exhaust pipe to heating system or to network heaters.
Turbines are the most complex elements of thermal power plants. The complexity of creating turbines is determined not only by high technological requirements for manufacturing, materials, etc., but mainly by extreme science intensity. Currently, the number of countries producing powerful steam turbines does not exceed ten. The most complex element is the LPC. The main manufacturers of turbines in Russia are the Leningrad Metal Plant (St. Petersburg) and the Turbomotor Plant (Ekaterinburg).
The low value of the efficiency of steam turbines determines the effectiveness of its priority increase. Therefore, the main attention is given below to the steam turbine installation.
The main potential methods for increasing the efficiency of steam turbines are:
· aerodynamic improvement of the steam turbine;
· improvement of the thermodynamic cycle, mainly by increasing the parameters of the steam coming from the boiler and reducing the pressure of the steam exhausted in the turbine;
· improvement and optimization of the thermal circuit and its equipment.
Aerodynamic improvement of turbines abroad over the past 20 years has been achieved using three-dimensional computer modeling of turbines. First of all, it is necessary to note the development saber blades. Saber blades are curved blades that resemble a saber in appearance (in foreign literature terms used "banana" And "three-dimensional")
Firm Siemens uses "three-dimensional" blades for the HPC and CSD (Fig. 3.6), where the blades have a short length, but a relatively large zone of high losses in the root and peripheral zones. According to Siemens estimates, the use spatial blades in HPC and CSD allows increasing their efficiency by 1 - 2% compared to cylinders created in the 80s of the last century.
Figure 3.6. “Three-dimensional” blades for high-pressure cylinders and central cylinders of the company Siemens
In Fig. 3.7 shows three successive modifications of working blades for high-pressure engines and the first stages of low-pressure engines of steam turbines for nuclear power plants of the company GEC-Alsthom: regular (“radial”) blade of constant profile (Fig. 3.7, A), used in our turbines; saber blade (Fig. 3.7, b) and, finally, a new blade with a straight radial exit edge (Fig. 3.7, V). The new blade provides an efficiency 2% greater than the original one (Fig. 3.7, A).
Figure 3.7. Working blades for steam turbines for nuclear power plants of the company GEC-Alsthom
Capacitor
The steam exhausted in the turbine (the pressure at the LPC outlet is 3 - 5 kPa, which is 25 - 30 times less than atmospheric) enters the capacitor. The condenser is a heat exchanger through the pipes of which cooling water supplied continuously circulates. circulation pumps from the reservoir. At the outlet of the turbine, a deep vacuum is maintained using a condenser. Figure 3.8 shows a two-pass condenser of a powerful steam turbine.
Figure 3.8. Two-pass condenser of a powerful steam turbine
The condenser consists of a welded steel body 8, along the edges of which condenser tubes 14 are fixed in the tube sheet. Condensate is collected in the condenser and is constantly pumped out by condensate pumps.
The front water chamber 4 is used to supply and remove cooling water. Water is supplied from below to the right side of chamber 4 and, through holes in the tube sheet, enters the cooling tubes, along which it moves to the rear (rotary) chamber 9. Steam enters the condenser from above and meets cold surface and condenses on them. Since condensation occurs at a low temperature, which corresponds to a low condensation pressure, a deep vacuum is created in the condenser (25-30 times less than atmospheric pressure).
In order for the condenser to provide low pressure behind the turbine, and, accordingly, steam condensation, a large amount of cold water. To generate 1 kWh of electricity, approximately 0.12 m 3 of water is required; One power unit of NchGRES uses 10 m 3 of water per 1 s. Therefore, thermal power plants are built either near natural sources water, or build artificial reservoirs. If it is not possible to use a large amount of water for steam condensation, instead of using a reservoir, the water can be cooled in special cooling towers - cooling towers, which due to their size are usually the most visible part of the power plant (Fig. 3.9).
From the condenser, the condensate is returned to the steam generator using a feed pump.
Figure 3.9. Appearance cooling towers of thermal power plants
TEST QUESTIONS FOR LECTURE 3
1. Structural diagram of a thermal power plant and the purpose of its elements – 3 points.
2. Thermal diagram TPP – 3 points.
3. Thermal balance of thermal power plants – 3 points.
4. Steam generator of thermal power plant. Purpose, types, structural diagram, efficiency – 3 points.
5. Steam parameters at thermal power plants – 5 points
6. Steam turbine. Device. Developments by Laval and Parsons - 3 points.
7. Multi-cylinder turbines – 3 points.
8. The efficiency of an ideal turbine is 5 points.
9. Condensing and heating steam turbines – 3 points.
10. What is the difference between CES and CHP? The efficiency of CES and CHP is 3 points.
11. TPP condenser – 3 points.
Depending on the power and technological features of power plants, it is possible to simplify the production structure of power plants: reducing the number of workshops to two - thermal power and electric at power plants of small capacity, as well as power plants operating on liquid and gaseous fuels, combining several power plants under the leadership of a general directorate with the transformation of individual power plants to the workshops.
There are three types of management at energy enterprises: administrative and economic, production and technical and operational and dispatch. In accordance with this, management bodies have been built, bearing the names of departments or services, staffed with employees with appropriate qualifications.
Administrative and economic management the general director carries out through the chief engineer, who is his first deputy. (The General Director may have deputies for administrative and economic activities, financial activities, capital construction, etc.). This includes functions for planning and implementing technical policy, introducing new equipment, monitoring uninterrupted operation, timely and high-quality repairs and so on.
Operational management of enterprises is carried out through a dispatch service. All lower-level duty officers at energy enterprises are operationally subordinate to the duty dispatcher. Here one of the features of energy enterprise management is revealed, which is that the duty personnel are in double subordination: in operational terms they are subordinate to the superior duty officer, and in administrative and technical terms - to their line manager.
The dispatch service, based on the approved plan for energy production and equipment repair, distributes the operating mode, based on the requirements of reliability and efficiency and taking into account the availability of fuel and energy resources, outlines measures to improve reliability and efficiency.
The functions of individual employees are determined by the functions of the relevant bodies - departments and services. The number of employees is regulated by the scope of functions performed, depending mainly on the type and power of the station, the type of fuel and other indicators that are expressed in the category assigned to the enterprise.
The administrative and economic head of the station is the director, who, within the limits of the rights granted to him, manages all the funds and property of the power plant, manages the work of the team, and compliance with financial, contractual, technical and labor discipline at the station. Directly subordinate to the director is one of the main departments of the station - the planning and economic department (PED).
The PEO is responsible for two main groups of issues: production planning and labor and wage planning. The main task of production planning is the development of long-term and current plans for the operation of thermal power plants and monitoring the implementation of planned operating indicators. For the proper organization and planning of labor and wages at thermal power plants, the department periodically photographs the working day of the main operating personnel and time-keeping the work of the personnel of the fuel, transport and mechanical repair shops.
TPP accounting carries out accounting of cash and material resources of the station (group - production); calculations of personnel wages (accounting part), current financing (banking operations), settlements under contracts (with suppliers, etc.), preparation of financial statements and balance sheets; control over the correct expenditure of funds and compliance with financial discipline.
At large stations, for the management of the administrative and economic department and the departments of material and technical supply, personnel and capital construction, the positions of special deputy directors (except for the first deputy chief engineer) for administrative and economic issues and for capital construction and assistant director for personnel are provided. At high-power stations, these departments (or groups), as well as accounting, report directly to the director.
Run by the department logistics(MTS) the station is supplied with all necessary operating materials (except for the main raw material - fuel), spare parts and materials and tools for repairs.
The HR department deals with the selection and study of personnel, formalizes the hiring and dismissal of employees.
The capital construction department carries out capital construction at the station or controls the progress of construction (if construction is carried out by contract), and also manages the construction of residential buildings at the station.
The technical manager of the thermal power plant is the first deputy director of the plant - Chief Engineer. The chief engineer is in charge of technical issues, organizes the development and implementation of advanced labor methods, rational use of equipment, economical consumption of fuel, electricity, and materials. Equipment repairs are carried out under the leadership of the chief engineer. He heads the qualification commission to test the technical knowledge and preparedness of the power plant’s engineering and technical workers. The production and technical department of the station is directly subordinate to the chief engineer.
Production and technical department(PTO) TPP develops and implements measures to improve production, performs operational and commissioning tests of equipment; develops, together with the PEO, annual and monthly technical plans for workshops and planned targets for individual units; studies the causes of accidents and injuries, keeps records and analyzes the consumption of fuel, water, steam, electricity and develops measures to reduce these costs; draws up technical reports for thermal power plants, monitors the implementation of the repair schedule; prepares requests for materials and spare parts.
The PTO usually includes three main groups: technical (energy) accounting, adjustment and testing, and repair and design.
The technical accounting group, based on the readings of water meters, parameters, electricity meters, determines electricity production and heat supply, steam and heat consumption, analyzes these data and their deviations from planned values; prepares monthly reports on the operation of power plants.
The commissioning and testing group is in charge of setting up and testing new equipment and equipment coming from repairs.
The repair and design group is in charge of major and current repairs of station equipment and the development of design changes (improvements) of individual equipment units, as well as issues of simplifying thermal circuits of thermal power plants.
The organizational and production structure of a thermal power plant (production management scheme) can be workshop or block.
Until now, the most common one was the shop management scheme. At shop diagram Energy production is divided into the following phases: preparation and on-site transportation of fuel (preparatory phase); conversion of chemical energy of fuel into mechanical energy of steam; conversion of mechanical energy of steam into electricity.
The control of individual phases of the energy process is carried out by the corresponding workshops of the power plant: fuel and transport (first, preparatory phase), boiler (second phase), turbine (third phase), electrical (fourth phase).
The thermal power plant workshops listed above, as well as the chemical workshop, are among the main ones, since they are directly involved in the technological process of the main production of the power plant.
In addition to the main production (for which this enterprise is created), auxiliary production is considered. Auxiliary workshops at thermal power plants include:
Thermal automation workshop and measurements (TAIZ), which is in charge of thermal control devices and automatic regulators of thermal processes of the station (with all auxiliary devices and elements), as well as supervision of the state of the weighing facilities of workshops and stations (except for carriage scales);
Mechanical shop, which is in charge of general station workshops, heating and ventilation units production and service buildings, fire and drinking water supply and sewerage systems, if the repair of station equipment is carried out by the thermal power plant itself, then the mechanical shop turns into a mechanical repair shop and its functions include carrying out scheduled preventive maintenance of equipment in all workshops of the station;
Repair and construction a workshop that carries out operational supervision of industrial office buildings and structures and their repair and carries out work to maintain roads and the entire territory of the power plant in proper condition.
All plant workshops (main and auxiliary) are administratively and technically subordinate directly to the chief engineer.
Each workshop is headed by a workshop manager. For all production and technical issues, he reports to the chief engineer of the thermal power plant, and for administrative and economic issues, he reports to the plant director. The head of the workshop organizes the work of the workshop team to fulfill planned targets, manages the funds of the workshop, and has the right to reward and impose disciplinary sanctions on the workshop workers.
Separate sections of the workshop are headed by foremen. The foreman is the site manager, responsible for the implementation of the plan, the placement and use of workers, the use and safety of equipment, the expenditure of materials, wage funds, occupational health and safety, correct labor regulation and other tasks facing the foreman require from him not only technical training, but also knowledge of the economics of production, its organization; he must understand the economic indicators of the work of his site, workshop, and enterprise as a whole. Foreman directly supervise the work of foremen and teams of workers.
The power equipment of the workshops is maintained by the workshop operational personnel on duty, organized into shift teams (watches). The work of each shift is supervised by duty shift supervisors of the main workshops, reporting to the station duty engineer (DIS)
DIS TES provides operational management of all on-duty operating personnel of the station during the shift. The duty engineer is administratively and technically subordinate to the chief engineer of the thermal power plant, but operationally he is subordinate only to the duty dispatcher of the power system and carries out all his orders for the operational management of the production process of the thermal power plant. In operational terms, the DIS is the sole commander of the station during the corresponding shift, and his orders are unconditionally carried out by the station's registered duty personnel through the corresponding shift supervisors of the main workshops. In addition to maintaining the regime, DIS immediately responds to all problems in the workshops and takes measures to eliminate them to prevent accidents and defects in the operation of power plants.
Another form of organizational structure is block diagram.
The main primary production unit of a block power plant is not a workshop, but a complex energy unit (block), which includes equipment that carries out not one, but several successive phases of the energy process (for example, from fuel combustion in the boiler furnace to the production of electricity by the generator of a steam turbine unit) and not having cross connections with other units - blocks. Energy blocks can include one turbine unit and one boiler fully providing it with steam (monoblock) or a turbine unit and two boilers of equal productivity (double block).
With a block diagram there is no separate control various types main equipment (boilers, turbines), i.e. "horizontal" control scheme. The equipment is controlled according to a “vertical” scheme (boiler-turbine unit) by the unit’s duty personnel.
General management of the power plant and control over the operation of equipment and operating personnel is concentrated in the operation service, subordinate to the deputy chief operation engineer.
It is envisaged to have a centralized repair shop (CRM), which carries out repairs of all equipment of the station, subordinate to the deputy chief engineer for repairs.
Operational management of the station is carried out by shift duty engineers of the station, subordinate in administrative and technical terms to the deputy chief engineer for operation, and in operational terms to the duty dispatcher of the power system.
Unlike a station with a workshop structure, the main primary production unit of a block station, as noted above, is one or two double blocks controlled from one control panel. The maintenance personnel of one control panel (for one or two blocks) includes the duty manager of a block or block system (two blocks), three-shift assistants to the head of the block system (panel room, turbine and boiler equipment); duty foreman (turbine and boiler equipment), two auxiliary equipment linemen (turbine and boiler units). In addition, linemen for the mine pumping station, ash removal, hydraulic structures, coastal pumping station and auxiliary workers are subordinate to the head of the block system.
The head of the block system is the operational manager of the operation of the equipment of the block and two (double) blocks, responsible for its trouble-free and economical operation in accordance with the rules of technical operation. One of his assistants is on duty at the block control panel and keeps a logbook. Two other assistants monitor the operation of boiler and turbine equipment during their shift.
The on-duty technicians, with the help of linemen, monitor the technical condition of boiler and turbine equipment on site and eliminate any identified defects. The mine pumping station attendant, together with auxiliary workers, maintains the ash removal system. A hydraulic structure lineman maintains the water supply system.
The station's fuel and transport facilities, led by the fuel supply shift manager, are allocated to an independent production unit.
Directly subordinate to the duty engineer of the station is an electrical engineer, an instrumentation and automation engineer, a master chemist and a master in oil production.
In addition to the duty (shift) personnel, the operation service includes station laboratories: heat measuring and metal control laboratory, electrical laboratory (including communications), chemical laboratory.
The currently used organizational structure of high-capacity block power plants can be called block-shop diagram, since, along with the creation of power boiler-turbine units, the shop division of the station and the centralization of control of all station “boiler-turbine” units in the integrated boiler-turbine shop are preserved.
In addition to the boiler-turbine shop (BTS), the organizational structure of the station includes: fuel and transport shop (with the participation of heat supply and underground communications); chemical workshop (with chemical laboratory); fuel automation and measurement workshop (with heat measuring laboratory); boiler-turbine equipment adjustment and testing workshop; centralized equipment repair shop (with a mechanical workshop).
For stations with a capacity of 800 MW or more, a separate dust preparation workshop is provided. At stations with a capacity of more than 1000 MW, burning multi-ash fuel and having a complex set of hydraulic structures, in organizational structure The hydraulic workshop is turned on.
The boiler and turbine shop (BTS) is in charge of the technical operation of all boiler and turbine equipment of the station (including all auxiliary equipment) and the operational management of all power (boiler and turbine units).
The shift supervisors of the dual power units, which are controlled from a common (two units) switchboard, report to the CTC shift manager.
The fuel and transport workshop includes: a fuel warehouse, railway tracks and rolling stock, an unloading shed, car dumpers, car scales and fuel supply paths.
An electric power plant is a power plant used to convert natural energy into electrical energy. The type of power plant is determined primarily by the type of natural energy. The most widespread are thermal power plants (TPPs), which use thermal energy released by burning fossil fuels (coal, oil, gas, etc.). 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. .
Basic principles of operation of thermal power plants (Appendix B). Let's consider the principles of operation of thermal power plants. Fuel and oxidizer, which is usually heated air, continuously flow into the boiler furnace (1). The fuel used is coal, peat, gas, oil shale or fuel oil. Most thermal power plants in our country use coal dust as fuel. Due to the heat generated as a result of fuel combustion, the water in the steam boiler is heated, evaporates, and the resulting saturated steam flows through a steam line into a steam turbine (2), designed to convert the thermal energy of steam into mechanical energy.
All moving parts of the turbine are rigidly connected to the shaft and rotate with it. In the turbine, the kinetic energy of the steam jets is transferred to the rotor as follows. Steam of high pressure and temperature, which has high internal energy, enters the nozzles (channels) of the turbine from the boiler. A jet of steam at a high speed, often above the sound speed, continuously flows out of the nozzles and enters the turbine blades mounted on a disk rigidly connected to the shaft. In this case, the mechanical energy of the steam flow is converted into mechanical energy of the turbine rotor, or more precisely, into the mechanical energy of the turbogenerator rotor, since the shafts of the turbine and electric generator (3) are interconnected. In an electric generator, mechanical energy is converted into electrical energy.
After the steam turbine, water vapor, already at low pressure and temperature, enters the condenser (4). Here, the steam, with the help of cooling water pumped through the tubes located inside the condenser, is converted into water, which is supplied to the deaerator (7) by a condensate pump (5) through regenerative heaters (6).
The deaerator is used to remove gases dissolved in it from water; at the same time, in it, just like in regenerative heaters, the feed water is heated by steam, taken for this purpose from the turbine outlet. Deaeration is carried out in order to bring to acceptable values the content of oxygen and carbon dioxide in it and thereby reduce the rate of corrosion in water and steam paths.
Deaerated water is supplied to the boiler plant by a feed pump (8) through heaters (9). The condensate of the heating steam formed in the heaters (9) is passed cascade into the deaerator, and the condensate of the heating steam of the heaters (6) is supplied drain pump(10) into the line through which condensate flows from the condenser (4).
The most difficult technically is the organization of the operation of coal-fired thermal power plants. At the same time, the share of such power plants in the domestic energy sector is high (~30%) and it is planned to increase it (Appendix D).
Fuel in railway cars (1) is supplied to unloading devices (2), from where it is sent to the warehouse (3) using belt conveyors (4), and from the warehouse the fuel is supplied to the crushing plant (5). It is possible to supply fuel to the crushing plant and directly from unloading devices. From the crushing plant, fuel flows into raw coal bunkers (6), and from there through feeders into pulverized coal mills (7). Coal dust is pneumatically transported through a separator (8) and a cyclone (9) to a coal dust hopper (10), and from there by feeders (11) to the burners. Air from the cyclone is sucked in by the mill fan (12) and supplied to the combustion chamber of the boiler (13).
The gases generated during combustion in the combustion chamber, after leaving it, pass sequentially through the gas ducts of the boiler installation, where in the steam superheater (primary and secondary, if a cycle with intermediate superheating of steam is carried out) and the water economizer they give off heat to the working fluid, and in the air heater - supplied to the steam boiler to air. Then, in ash collectors (15), the gases are purified from fly ash and released into the atmosphere through the chimney (17) by smoke exhausters (16).
Slag and ash falling under the combustion chamber, air heater and ash collectors are washed off with water and flow through channels to the bagger pumps (33), which pump them to ash dumps.
The air required for combustion is supplied to the air heaters of the steam boiler by a blower fan (14). Air is usually taken from the top of the boiler room and (for high-capacity steam boilers) from outside the boiler room.
Superheated steam from the steam boiler (13) enters the turbine (22).
Condensate from the turbine condenser (23) is supplied by condensate pumps (24) through low-pressure regenerative heaters (18) to the deaerator (20), and from there by feed pumps (21) through high-pressure heaters (19) to the boiler economizer.
In this scheme, the losses of steam and condensate are replenished with chemically demineralized water, which is supplied to the condensate line behind the turbine condenser.
Cooling water is supplied to the condenser from the receiving well (26) of the water supply by circulation pumps (25). The heated water is discharged into a waste well (27) of the same source at a certain distance from the point of intake, sufficient to ensure that the heated water does not mix with the taken water. Devices for chemical treatment of make-up water are located in the chemical workshop (28).
The schemes may provide for a small network heating installation for district heating of the power plant and the adjacent village. Steam is supplied to the network heaters (29) of this installation from turbine extractions, and condensate is discharged through line (31). Network water is supplied to the heater and removed from it through pipelines (30).
The generated electrical energy is removed from the electrical generator to external consumers through step-up electrical transformers.
To supply electric motors, lighting devices and devices of the power plant with electricity, there is an electrical Switchgear own needs (32) .
Combined heat and power plant (CHP) is a type of thermal power plant that produces not only electricity, but is also a source of thermal energy in centralized systems heat supply (in the form of steam and hot water, including for providing hot water supply and heating of residential and industrial facilities). The main difference between a thermal power plant is the ability to take away part of the thermal energy of the steam after it has generated electrical energy. Depending on the type of steam turbine, there are various steam extractions that allow you to extract steam with different parameters from it. CHP turbines allow you to regulate the amount of extracted steam. The selected steam is condensed in network heaters and transfers its energy to network water, which is sent to peak water heating boilers and heating points. At thermal power plants it is possible to shut off thermal steam extraction. This makes it possible to operate the CHP plant according to two load schedules:
· electrical - the electrical load does not depend on the thermal load, or there is no thermal load at all (priority is the electrical load).
When constructing a thermal power plant, it is necessary to take into account the proximity of heat consumers in the form of hot water and steam, since heat transfer over long distances is not economically feasible.
CHP plants use solid, liquid or gaseous fuel. Due to the greater proximity of thermal power plants to populated areas, they use more valuable fuels that pollute the atmosphere less with solid emissions - fuel oil and gas. To protect the air basin from pollution by solid particles, ash collectors are used; to disperse solid particles, sulfur and nitrogen oxides in the atmosphere, they are built chimneys height up to 200-250 m. CHP plants built near heat consumers are usually located at a considerable distance from water supply sources. Therefore, most thermal power plants use a circulating water supply system with artificial coolers - cooling towers. Direct-flow water supply at thermal power plants is rare.
At gas turbine thermal power plants as a drive electrical generators use gas turbines. Heat supply to consumers is carried out due to the heat taken from the cooling of the air compressed by the compressors of the gas turbine unit, and the heat of the gases exhausted in the turbine. Combined-cycle power plants (equipped with steam turbine and gas turbine units) and nuclear power plants can also operate as thermal power plants.
CHP is the main production link in the centralized heat supply system (Appendix E, E).