Ministry of Education and Science Russian Federation

Federal Agency for Education

GOU VPO "Magnitogorsk State Technical

University named after G.I. Nosova

Department of Thermal Engineering

And energy systems

Guidelines

to laboratory work

“Study of the thermal diagram of the heat treatment plant of the thermal power plant of OJSC MMK and the heating point of the main building of MSTU”

in the discipline “Sources and heat supply systems for enterprises”

for students of specialty 140104 “Industrial Thermal Power Engineering”

Magnitogorsk

2009
Compiled by: Art. Rev. S.V. Oskolkov, st. Rev. V.F. Tolmacheva, Shestakov M.S., Mukhamedyarov E.A.

Study of the thermal diagram of the heat treatment plant of the thermal power plant of OJSC MMK and the heating unit of the main building of MSTU: Guidelines for laboratory work in the discipline “Boiler installations and steam generators” for students of specialty 140104 “Industrial Heat and Power Engineering”. Magnitogorsk: State Educational Institution of Higher Professional Education MSTU named after. G.I. Nosova, 2009. 10 p.

Reviewer: Associate Professor of the Department of Gas Supply, Ventilation and Urban Management, MSTU, Ph.D., G.N. Trubitsyna

O Oskolkov S.V., Tolmacheva V.F.,

Shestakov M.S., Mukhamedyarov E.A., 2009

Purpose of the work:

1. Familiarize yourself with the technological process and thermal scheme for the preparation of coolants and the main heating networks of the thermal power plant of OJSC MMK.
2. Get acquainted with the work of the MTP of the Main building of MSTU and draw thermal diagram with the designation of the main equipment of the MTP.
3. Study the operational diagrams of the boiler rooms of the Right (Left) bank of the thermal power plant of OJSC MMK.

Equipment used

Stationary equipment - elevator, water-water heat exchangers for hot water supply, mud traps, heat pipelines, shut-off and control valves, pressure gauges and thermometers (MTP equipment of the Main building of MSTU).

General information

A thermal power plant is an enterprise whose products are electricity, as well as heat released in the form of steam and hot water, and the “raw material” is organic fuel (coal, gas). The power plant equipment is used to economically convert chemical energy into electrical energy.

Technological process of thermal power plant.

Let's consider the technological process of producing electricity and heat at a coal-fired thermal power plant (Figure 1).

The main elements of the power plant in question are a boiler plant that produces steam of high parameters; a turbine or steam turbine installation that converts the heat of steam into mechanical energy of rotation of the rotor of a turbine unit, and electrical devices(generator, transformers, etc.) providing electricity generation.

The main element of a boiler installation is the boiler. Coal arriving at the thermal power plant in special cars is unloaded, crushed to a size of pieces of 20-25 mm and conveyed by a belt conveyor into bunker 19, which has a supply of coal for several hours of operation. From the bunker, coal enters mill 13, in which it is ground to a powder state. Hot air, heated in the air heater 8, is continuously supplied to the mill by a special blowing fan 9. The hot air is mixed with coal dust and through the burners of the boiler is fed into its furnace - the chamber in which fuel combustion occurs. When pulverized fuel burns, a torch is formed, which is a powerful source of radiant energy, the flame temperature exceeds 1500°C. Thus, when the fuel burns, it is chemical energy turns into thermal and radiant energy of the torch.

The furnace walls are lined with 20 screens - pipes to which feed water is supplied from the economizer. The thermal power plant has drum boilers, in the screens of which multiple circulation of feed water is carried out, and steam is separated from the boiler water in the drum.

Dry saturated steam enters the superheater 6, in which its temperature and, consequently, potential energy increases.

The gaseous products of fuel combustion, having given up their main heat to the feed water, enter the pipes of the economizer 7 and the air heater 8, in which they are cooled to a temperature of 140-160 ° C and sent using a smoke exhauster 11 to the chimney 12. In the electric precipitators 10, dry volatiles are captured ash. Smoke exhauster and chimney create a vacuum in the furnace and gas ducts of the boiler; in addition, the chimney disperses harmful combustion products in the upper layers of the atmosphere, preventing their high concentration in lower layers. Ash formed during fuel combustion and not carried away by the gas flow is removed from the bottom of the furnace and transported to ash dumps.

The high-parameter steam obtained at the exit from the boiler plant is supplied through the steam line 4 to the steam turbine 3. Expanding in it, the steam rotates its rotor, connected to the rotor of the electric generator 2, in the windings of which an electric current is generated. Transformers 1 increase its voltage to reduce losses in power lines, transfer part of the generated energy to power the power plant's own needs, and the rest to the electrical system.

Both the boiler and the turbine can only operate at very high quality feed water and steam, allowing negligible admixtures of other substances. In addition, steam consumption is enormous (for example, in boiler units of thermal power plants, approximately 0.5 tons of water evaporate in 1 second). Therefore, nominal operation of the power unit is possible only by creating a closed circulation cycle of the working fluid of high purity. The steam leaving the turbine 3 enters the condenser 17 - a heat exchanger, through the tubes of which the cold water, supplied circulation pump from the Ural River. The steam coming from the turbine into the intermediate space of the condenser condenses and flows down. The resulting condensate is supplied by the condensate pump 16 through the regenerative heater 15 to the deaerator 5. In the heater 15, the temperature of the condensate increases due to the heat of the steam taken from the turbine. This will reduce fuel consumption in the boiler and increase the efficiency of the power plant. In the deaerator, deaeration occurs - the removal of gases dissolved in it from the condensate, which disrupt the operation of the boiler. At the same time, the deaerator tank is a container for boiler feed water.

From the deaerator, feed water is supplied to the boiler by a feed pump 14 driven by an electric motor. This closes the technological cycle of converting the chemical energy of the fuel into the mechanical energy of rotation of the turbine rotor.

Heat is supplied to consumers by extracting steam from the turbine, in the same way as is done for regenerative heating of feedwater. For heating purposes, steam from the so-called turbine heating outlet is sent to network heaters, in the tubes of which network (heating) water circulates. Network heaters are installed in the turbine section of the thermal power plant.

The considered thermal power plant diagram can be depicted on a thermal diagram - graphical representation individual elements and pipelines using symbols.

CHPP of OJSC MMK.

The thermal power plant of OJSC MMK is a large thermal station with great value for stable independent operation of the Magnitogorsk Iron and Steel Works.

The thermal power plant covers about a third of the plant’s electricity needs, provides consumers with steam of high and medium parameters and hot water. From efficient work CHP depends successful work all redistributions of OJSC MMK. The thermal power plant supplies heat to the plant and the left bank part of the city, as well as part of the right bank, the area from the street. Gagarina to st. Soviet Army. In addition to generating electricity, the thermal power plant produces:

• industrial water With pumping stations No. 16, 16A for the technological needs of the oxygen compressor shop;
• chemically purified water from the chemical water treatment plant (CWT) of the thermal power plant for the needs of the plant.

In order to control technological processes at the thermal power plant, the most efficient power and auxiliary equipment was distributed among the following sections: fuel and transport section, water chemical, boiler room, turbine section, thermal automation and measurement section, electrical section.

The thermal power plant of OJSC MMK produces the following types of energy resources:

1) Electricity. Through the 110 kV power grid, the thermal power plant is connected to other power plants of the plant and the system of Chelyabenergo JSC.

2) Thermal energy. Thermal energy is supplied from the CHP plant:

• with hot water for district heating of the city and plant
• with live steam (P=10MPa, t=500°C) to the compressor turbines of KCC No. 4
• with saturated steam from a steam conversion unit for the technological needs of the plant.

3) Chemically purified water. It is released for the technological needs of the plant and to replenish losses of network water.

4) Process water. Sold to the water supply workshop.

Installed capacity of the thermal power plant:

Electric 300 MW

For heat and hot water supply 886 MW, incl. 327 MW.

For steam release from the steam generating unit 120t/h.

Chemical water treatment capacity 500t/h

The capacity of pumping stations is 172,000 t/h.

Boiler units and turbogenerators belong to the main energy equipment. Auxiliary equipment includes: condensate, drain, feed, oil and other pumps, boiler units, oil facilities, regenerative heaters, deaerators, etc. Technical characteristics of boilers and turbogenerators are given in Tables 1 and 2, respectively.

Table 1. Specifications

Electricity is produced at power plants, often using electromechanical induction generators. There are 2 main types of power plants − thermal power plants(TPP) and hydroelectric power plants (HPP) - differing in the nature of the engines that rotate the rotors of the generators.

The source of energy at thermal power plants is fuel: fuel oil, oil shale, oil, coal dust. The rotors of electric generators are driven into rotation using steam and gas turbines or engines internal combustion(ICE).

As is known, the efficiency of heat engines increases with increasing initial temperature of the working fluid. Therefore, the steam that enters the turbine is brought to about 550 °C at a pressure of about 25 MPa. The efficiency of thermal power plants reaches 40%.

At thermal power plants (CHP), most of the energy from waste steam is used in industrial enterprises and for domestic needs. The efficiency of thermal power plants can reach 60-70%.

At hydroelectric power stations, the potential energy of water is used to rotate the rotors of generators. The rotors are driven by hydraulic turbines.

The power of the station depends on the difference in water levels that are created by the dam (pressure), and on the mass of water that passes through the turbine in 1 second (water flow).

Part of the electricity consumed in Russia (approximately 10%) is produced at nuclear power plants(NPP).

Electricity transmission.

Basically, this process is accompanied by significant losses that are associated with the heating of power line wires by current. According to the Joule-Lenz law, the energy that is spent on heating the wires is proportional to the square of the current strength and the line resistance, so when long length power transmission lines may become economically unprofitable. Therefore, it is necessary to reduce the current, which, for a given transmitted power, leads to the need to increase the voltage. The longer the power line, the more profitable it is to use higher voltages (on some, the voltage reaches 500 kV). Generators AC produce voltages that cannot exceed 20 kV (which is due to the properties of the insulating materials used).

Therefore, step-up transformers are installed at power plants, which increase the voltage and reduce the current by the same amount. To supply electricity consumers with the required (low) voltage, step-down transformers are installed at the ends of the power transmission line. Voltage reduction is usually done in stages.

Electricity use.

Main consumers of electricity:

1. industry - 70%;
2. transport (electric traction);
3. household consumers (home lighting, electrical appliances).

Almost all electrical energy used is converted into mechanical energy. Almost all mechanisms in industry are driven by electric motors.

Approximately a third of the electricity consumed by industry is used for technological purposes (electric welding, electric heating and metal smelting, electrolysis and so on).

Let us consider the movement of a conductor in a plane perpendicular to the direction of the field, when one end of the conductor is stationary and the other describes a circle. Electromotive force at the ends of the conductor is determined by the formula of the law of electromagnetic induction. A machine running...

Energy production should be understood as the transformation of energy from an “inconvenient” form for human use to a “convenient” form. For example, sunlight can be used by receiving it directly from the Sun, or it can be generated from it, which in turn will be converted into light indoors. You can burn gas in an internal combustion engine, converting it into - shaft rotation. Or you can burn gas in a fuel cell, converting the same chemical energy of bonds into electromagnetic energy, which will then be converted into mechanical energy of shaft rotation. The efficiency of different energy conversion algorithms varies. However, this is not a consequence of the “damage” of certain energy chains. The reason for the difference in efficiency is at different levels technology development. For example, the efficiency of large diesel engines installed on ocean-going oil tankers and container ships is significantly higher than the efficiency of automobile diesel engines. However, many times more is removed from a car engine horsepower, and in the end you have to pay with a decrease in efficiency.

In general, centralized energy looks attractive only at first glance

For example, hydroelectric power stations provide a lot of free electricity, but they are very expensive to build, have a destructive impact on the ecology of the region, and force settlements to be moved and cities to be built. And in arid countries, the consequences of the construction of hydroelectric power stations lead to the dehydration of entire regions, where residents do not even have enough water for drinking, let alone for agriculture. Nuclear power plants look attractive, but production creates the problem of disposal and disposal of highly radioactive waste. Thermal plants aren't so bad either, since they account for the vast majority of production and electricity. But they release carbon dioxide into the atmosphere and reduce mineral reserves. But why are we building all these stations, transmitting, converting and losing huge amounts of energy. The fact is that we need specific energy - electricity. But it is possible to build production and life processes in which there is no need to either produce energy at a significant distance from the consumer or transmit it over long distances. For example, the problem of obtaining hydrogen will be very difficult if we start producing it as fuel for cars on a global scale. The separation of hydrogen from water by electrolysis is a very energy-intensive process that would require doubling global electricity production if all cars were converted to hydrogen.

But is it really necessary to “plant” hydrogen production at old capacities?

After all, it is possible to separate hydrogen from ocean water on floating platforms using solar energy. Then it turns out that solar energy is reliably “canned” in hydrogen fuel and transported wherever needed. After all, this is much more profitable than transmitting and storing electricity. Today, the following devices and structures are used for energy production: furnaces, internal combustion engines, electric generators, turbines, solar panels, wind turbines and power plants, dams and hydroelectric power stations, tidal stations, geothermal stations, nuclear power plants, thermonuclear reactors.

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 high-pressure steam. This steam, having a pressure of about 240 kilograms per square centimeter and a temperature of 524°C (1000°F), drives 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 thereby produce much more steam.

in physics

on the topic “Production, transmission and use of electricity”

11th grade A students

Municipal educational institution No. 85

Catherine.

Abstract plan.

Introduction.

1. Electricity production.

1. types of power plants.

2. alternative sources energy.

2. Electricity transmission.

transformers.

3. Electricity use.

Introduction.

The birth of energy occurred several million years ago, when people learned to use fire. Fire gave them warmth and light, was a source of inspiration and optimism, a weapon against enemies and wild animals, a healing agent, an assistant in agriculture, a food preservative, a technological tool, etc.

The wonderful myth about Prometheus, who gave people fire, appeared in Ancient Greece much later, in many parts of the world, methods of quite sophisticated handling of fire, its production and extinguishing, preservation of fire and rational use of fuel were mastered.

For many years, fire was maintained by burning plant energy sources (wood, shrubs, reeds, grass, dry algae, etc.), and then it was discovered that it was possible to use fossil substances to maintain fire: coal, oil, shale, peat.

Today, energy remains the main component of human life. It makes it possible to create various materials, is one of the main factors in the development of new technologies. Simply put, without mastering various types energy, a person is not able to fully exist.

Electricity production.

Types of power plants.

Thermal power plant (TPP), a power plant that generates electrical energy as a result of the conversion of thermal energy released during the combustion of fossil fuels. The first thermal power plants appeared at the end of the 19th century and became widespread. In the mid-70s of the 20th century, thermal power plants were the main type of power plants.

In thermal power plants, the chemical energy of the fuel is converted first into mechanical energy and then into electrical energy. The fuel for such a power plant can be coal, peat, gas, oil shale, and fuel oil.

Thermal power plants are divided into condensation(IES), designed to generate only electrical energy, and combined heat and power plants(CHP), producing in addition to electrical thermal energy in the form of hot water and steam. Large CPPs of regional significance are called state district power plants (SDPPs).

The simplest circuit diagram A coal-fired IES is shown in the figure. Coal is fed into the fuel bunker 1, and from it into the crushing unit 2, where it turns into dust. Coal dust enters the furnace of a steam generator (steam boiler) 3, which has a system of tubes in which chemically purified water, called feedwater, circulates. In the boiler, the water is heated, evaporated, and the resulting saturated steam is brought to a temperature of 400-650 °C and, under a pressure of 3-24 MPa, enters steam turbine 4 through a steam line. Steam parameters depend on the power of the units.

Thermal condensing power plants have low efficiency (30-40%), since most of the energy is lost with flue gases and condenser cooling water. It is advantageous to construct CPPs in close proximity to fuel production sites. In this case, electricity consumers may be located at a considerable distance from the station.

Combined heat and power plant differs from a condensing station by the special heating turbine installed on it with steam extraction. At a thermal power plant, one part of the steam is completely used in the turbine to generate electricity in the generator 5 and then enters the condenser 6, and the other, having high temperature and pressure is taken from the intermediate stage of the turbine and is used for heat supply. The condensate is supplied by pump 7 through the deaerator 8 and then by the feed pump 9 to the steam generator. The amount of steam taken depends on the thermal energy needs of enterprises.

Coefficient useful action CHP reaches 60-70%. Such stations are usually built near consumers - industrial enterprises or residential areas. Most often they run on imported fuel.

Thermal stations with gas turbine(GTPP), steam-gas(PHPP) and diesel plants.

Gas or liquid fuel is burned in the combustion chamber of a gas turbine power plant; combustion products with a temperature of 750-900 ºС enter a gas turbine that rotates an electric generator. The efficiency of such thermal power plants is usually 26-28%, power - up to several hundred MW . GTPPs are usually used to cover electrical load peaks. The efficiency of PGES can reach 42 - 43%.

The most economical are large thermal steam turbine power plants (abbreviated TPP). Most thermal power plants in our country use coal dust as fuel. To generate 1 kWh of electricity, several hundred grams of coal are consumed. In a steam boiler, over 90% of the energy released by the fuel is transferred to steam. In the turbine, the kinetic energy of the steam jets is transferred to the rotor. The turbine shaft is rigidly connected to the generator shaft.

Modern steam turbines for thermal power plants - very advanced, high-speed, highly economical machines with a long service life. Their power in a single-shaft version reaches 1 million 200 thousand kW, and this is not the limit. Such machines are always multi-stage, that is, they usually have several dozen disks with working blades and the same number, in front of each disk, of groups of nozzles through which a stream of steam flows. The pressure and temperature of the steam gradually decrease.

It is known from a physics course that the efficiency of heat engines increases with increasing initial temperature of the working fluid. Therefore, the steam entering the turbine is brought to high parameters: temperature - almost 550 ° C and pressure - up to 25 MPa. The efficiency of thermal power plants reaches 40%. Most of the energy is lost along with the hot exhaust steam.

Hydroelectric station (hydroelectric power station), a complex of structures and equipment through which the energy of water flow is converted into electrical energy. A hydroelectric power station consists of a series circuit hydraulic structures, providing the necessary concentration of water flow and creating pressure, and energy equipment that converts the energy of water moving under pressure into mechanical rotational energy, which, in turn, is converted into electrical energy.

The pressure of a hydroelectric power station is created by the concentration of the fall of the river in the area used by the dam, or derivation, or a dam and diversion together. The main power equipment of the hydroelectric power station is located in the hydroelectric power station building: in the turbine room of the power plant - hydraulic units, auxiliary equipment, devices automatic control and control; in the central control post - operator-dispatcher console or auto operator of a hydroelectric power station. Increasing transformer substation It is located both inside the hydroelectric power station building and in separate buildings or in open areas. Switchgears often located in an open area. A hydroelectric power plant building can be divided into sections with one or more units and auxiliary equipment, separated from adjacent parts of the building. An installation site is created at or inside the hydroelectric power station building for the assembly and repair of various equipment and for auxiliary operations for the maintenance of the hydroelectric power station.

According to installed capacity (in MW) distinguish between hydroelectric power stations powerful(over 250), average(up to 25) and small(up to 5). The power of a hydroelectric power station depends on the pressure (the difference between the levels of the upstream and downstream ), water flow used in hydraulic turbines and the efficiency of the hydraulic unit. For a number of reasons (due to, for example, seasonal changes water level in reservoirs, fluctuations in the load of the power system, repair of hydraulic units or hydraulic structures, etc.) the pressure and flow of water are constantly changing, and, in addition, the flow changes when regulating the power of a hydroelectric power station. There are annual, weekly and daily cycles of hydroelectric power station operation.

Based on the maximum used pressure, hydroelectric power stations are divided into high-pressure(more than 60 m), medium-pressure(from 25 to 60 m) And low-pressure(from 3 to 25 m). On lowland rivers pressures rarely exceed 100 m, in mountainous conditions, a dam can create pressures of up to 300 m and more, and with the help of derivation - up to 1500 m. The division of hydroelectric power stations according to the pressure used is of an approximate, conditional nature.

According to the pattern of water resource use and pressure concentration, hydroelectric power stations are usually divided into channel , dam , diversion with pressure and non-pressure diversion, mixed, pumped storage And tidal .

In run-of-river and dam-based hydroelectric power plants, the water pressure is created by a dam that blocks the river and raises the water level in the upper pool. At the same time, some flooding of the river valley is inevitable. Run-of-river and dam-side hydroelectric power stations are built both on lowland high-water rivers and on mountain rivers, in narrow compressed valleys. Run-of-river hydroelectric power plants are characterized by pressures up to 30-40 m.

At higher pressures, it turns out to be inappropriate to transfer hydrostatic water pressure to the hydroelectric power station building. In this case the type is used dam A hydroelectric power station, in which the pressure front is blocked along its entire length by a dam, and the hydroelectric power station building is located behind the dam, is adjacent to the tailwater.

Another type of layout dammed The hydroelectric power station corresponds to mountain conditions with relatively low river flows.

IN derivational Hydroelectric power station concentration of the river fall is created through diversion; Water at the beginning of the used section of the river is diverted from the river bed by a conduit with a slope significantly less than the average slope of the river in this section and with straightening the bends and turns of the channel. The end of the diversion is brought to the location of the hydroelectric power station building. Waste water is either returned to the river or supplied to the next diversion hydroelectric power station. Diversion is beneficial when the river slope is high.

A special place among hydroelectric power stations is occupied by pumped storage power plants(PSPP) and tidal power plants(PES). The construction of pumped storage power plants is driven by the growing demand for peak power in large energy systems, which determines the generating capacity required to cover peak loads. The ability of pumped storage power plants to accumulate energy is based on the fact that there is free energy in the energy system during a certain period of time. electrical energy used by pumped storage power plant units, which, operating in pump mode, pump water from the reservoir into the upper storage pool. During load peaks, the accumulated energy is returned to the power system (water from the upper pool enters the pressure pipeline and rotates hydraulic units operating as a current generator).

PES convert the energy of sea tides into electricity. The electricity of tidal hydroelectric power stations, due to some features associated with the periodic nature of the ebb and flow of tides, can be used in energy systems only in conjunction with the energy of regulating power plants, which make up for the power failures of tidal power stations within days or months.

The most important feature of hydropower resources compared to fuel and energy resources is their continuous renewability. The absence of fuel requirement for hydroelectric power plants determines the low cost of electricity generated by hydroelectric power plants. Therefore, the construction of hydroelectric power stations, despite significant specific capital investments by 1 kW installed capacity and long construction periods were and are given great importance, especially when this is associated with the placement of electricity-intensive industries.

Nuclear power plant (NPP), a power plant in which atomic (nuclear) energy is converted into electrical energy. The energy generator at a nuclear power plant is nuclear reactor. The heat that is released in the reactor as a result of the chain reaction of fission of the nuclei of some heavy elements is then converted into electricity in the same way as in conventional thermal power plants (TPPs). Unlike thermal power plants that run on fossil fuels, nuclear power plants run on nuclear fuel(based on 233 U, 235 U, 239 Pu). It has been established that the world's energy resources of nuclear fuel (uranium, plutonium, etc.) significantly exceed the energy resources of natural reserves of organic fuel (oil, coal, natural gas etc.). This opens up broad prospects for meeting rapidly growing fuel demands. In addition, it is necessary to take into account the ever-increasing volume of consumption of coal and oil for technological purposes in the world. chemical industry, which is becoming a serious competitor to thermal power plants. Despite the discovery of new deposits of organic fuel and the improvement of methods for its production, there is a tendency in the world towards a relative increase in its cost. This creates the most difficult conditions for countries with limited reserves of fossil fuels. There is an obvious need for the rapid development of nuclear energy, which already occupies a prominent place in the energy balance of a number of industrial countries around the world.

Schematic diagram of a nuclear power plant with nuclear reactor, having water cooling, is shown in Fig. 2. Heat released in core reactor coolant, is taken in by water from the 1st circuit, which is pumped through the reactor by a circulation pump. Heated water from the reactor enters the heat exchanger (steam generator) 3, where it transfers the heat received in the reactor to the water of the 2nd circuit. The water of the 2nd circuit evaporates in the steam generator, and steam is formed, which then enters the turbine 4.

Most often, 4 types of thermal neutron reactors are used at nuclear power plants:

1) water-water with plain water as a moderator and coolant;

2) graphite-water with water coolant and graphite moderator;

3) heavy water with water coolant and heavy water as a moderator;

4) graffito - gas with gas coolant and graphite moderator.

The choice of the predominantly used reactor type is determined mainly by the accumulated experience in the carrier reactor, as well as the availability of the necessary industrial equipment, raw materials reserves, etc.

The reactor and its servicing systems include: the reactor itself with biological protection , heat exchangers, pumps or gas-blowing units that circulate the coolant, pipelines and fittings for the circulation circuit, devices for reloading nuclear fuel, special ventilation systems, emergency cooling systems, etc.

To protect nuclear power plant personnel from radiation exposure, the reactor is surrounded by biological shielding, the main materials for which are concrete, water, and serpentine sand. The reactor circuit equipment must be completely sealed. A system is provided to monitor places of possible coolant leaks; measures are taken to ensure that leaks and breaks in the circuit do not lead to radioactive emissions and contamination of the nuclear power plant premises and the surrounding area. Radioactive air and a small amount of coolant vapor, due to the presence of leaks from the circuit, are removed from unattended rooms of the nuclear power plant by a special ventilation system, in which purification filters and holding gas tanks are provided to eliminate the possibility of air pollution. The compliance with radiation safety rules by NPP personnel is monitored by the dosimetry control service.

The presence of biological protection, special ventilation and emergency cooling systems and a dosimetric monitoring service makes it possible to completely protect NPP operating personnel from the harmful effects of radioactive radiation.

Nuclear power plants, which are the most modern look power plants have a number of significant advantages over other types of power plants: under normal operating conditions, they do not pollute the environment at all, do not require connection to a source of raw materials and, accordingly, can be located almost anywhere. New power units have a capacity almost equal to that of an average hydroelectric power station, but the installed capacity utilization factor at a nuclear power plant (80%) significantly exceeds this figure for a hydroelectric power station or thermal power plant.

NPPs have practically no significant disadvantages under normal operating conditions. However, one cannot fail to notice the danger of nuclear power plants under possible force majeure circumstances: earthquakes, hurricanes, etc. - here old models of power units pose a potential danger of radiation contamination of territories due to uncontrolled overheating of the reactor.

Alternative energy sources.

Solar energy.

Recently there has been interest in the problem of using solar energy has increased sharply, because the potential for energy based on the use of direct solar radiation is extremely high.

The simplest solar radiation collector is a blackened metal (usually aluminum) sheet, inside of which there are pipes with a liquid circulating in it. Heated by solar energy absorbed by the collector, the liquid is supplied for direct use.

Solar energy is one of the most material-intensive types of energy production. Large-scale use of solar energy entails a gigantic increase in the need for materials, and, consequently, in labor resources for the extraction of raw materials, their enrichment, obtaining materials, manufacturing heliostats, collectors, other equipment, and their transportation.

So far, electrical energy generated by the sun's rays is much more expensive than that obtained by traditional methods. Scientists hope that the experiments they will conduct at pilot installations and stations will help solve not only technical, but also economic problems.

Wind energy.

The energy of moving air masses is enormous. The reserves of wind energy are more than a hundred times greater than the hydropower reserves of all the rivers on the planet. Winds blow constantly and everywhere on earth. Climatic conditions allow the development of wind energy over a vast territory.

But today, wind engines supply just one thousandth of the world's energy needs. Therefore, aircraft specialists who know how to select the most appropriate blade profile and study it in a wind tunnel are involved in creating the designs of the wind wheel, the heart of any wind power plant. Through the efforts of scientists and engineers, a wide variety of designs of modern wind turbines have been created.

Energy of the Earth.

People have long known about the spontaneous manifestations of gigantic energy hidden in the depths of the globe. The memory of mankind contains legends about catastrophic volcanic eruptions that claimed millions of human lives and changed the appearance of many places on Earth beyond recognition. The power of the eruption of even a relatively small volcano is colossal, it is many times greater than the power of the largest power plants created by human hands. True, there is no need to talk about the direct use of the energy of volcanic eruptions; people do not yet have the ability to curb this rebellious element.

The Earth's energy is suitable not only for heating premises, as is the case in Iceland, but also for generating electricity. Power plants using hot underground springs have been operating for a long time. The first such power plant, still very low-power, was built in 1904 in the small Italian town of Larderello. Gradually, the power of the power plant grew, more and more new units were put into operation, new sources of hot water were used, and today the power of the station has already reached an impressive value of 360 thousand kilowatts.

Electricity transmission.

Transformers.

You purchased a ZIL refrigerator. The seller warned you that the refrigerator is designed for a mains voltage of 220 V. And in your house the mains voltage is 127 V. A hopeless situation? Not at all. You just have to make an additional expense and purchase a transformer.

Transformer- a very simple device that allows you to both increase and decrease voltage. The conversion of alternating current is carried out using transformers. Transformers were first used in 1878 by the Russian scientist P. N. Yablochkov to power the “electric candles” he invented, a new light source at that time. P. N. Yablochkov’s idea was developed by Moscow University employee I. F. Usagin, who designed improved transformers.

The transformer consists of a closed iron core, on which two (sometimes more) coils with wire windings are placed (Fig. 1). One of the windings, called the primary winding, is connected to an alternating voltage source. The second winding, to which the “load” is connected, i.e., instruments and devices that consume electricity, is called secondary.

The operation of a transformer is based on the phenomenon of electromagnetic induction. When alternating current passes through the primary winding, an alternating magnetic flux appears in the iron core, which excites an induced emf in each winding. Moreover, the instantaneous value of the induced emf e V any turn of the primary or secondary winding according to Faraday’s law is determined by the formula:

e = - Δ F/ Δ t

If F= Ф 0 сosωt, then

e = ω Ф 0 sin ω t , or

e = E 0 sin ω t ,

Where E 0 = ω Ф 0 - amplitude of the EMF in one turn.

In the primary winding, which has n 1 turns, total induced emf e 1 equal to p 1 e.

In the secondary winding there is a total emf. e 2 equal to p 2 e, Where n 2- the number of turns of this winding.

It follows that

e 1 e 2 = n 1 n 2 . (1)

Sum voltage u 1 , applied to the primary winding, and EMF e 1 should be equal to the voltage drop in the primary winding:

u 1 + e 1 = i 1 R 1 , Where R 1 - active resistance of the winding, and i 1 - current strength in it. This equation follows directly from the general equation. Usually the active resistance of the winding is small and i 1 R 1 can be neglected. That's why

u 1 ≈ -e 1 . (2)

When the secondary winding of the transformer is open, no current flows in it, and the following relationship holds:

u 2 ≈ - e 2 . (3)

Since instant EMF values e 1 And e 2 change in phase, then their ratio in formula (1) can be replaced by the ratio of effective values E 1 And E 2 of these EMFs or, taking into account equalities (2) and (3), the ratio of effective voltage values ​​U 1 and U 2 .

U 1 /U 2 = E 1 / E 2 = n 1 / n 2 = k . (4)

Magnitude k called the transformation ratio. If k>1, then the transformer is step-down, when k <1 - increasing

When the secondary winding circuit is closed, current flows in it. Then the ratio u 2 ≈ - e 2 is no longer fulfilled exactly, and accordingly the connection between U 1 and U 2 becomes more complex than in equation (4).

According to the law of conservation of energy, the power in the primary circuit must be equal to the power in the secondary circuit:

U 1 I 1 = U 2 I 2, (5)

Where I 1 And I 2 - effective values ​​of force in the primary and secondary windings.

It follows that

U 1 /U 2 = I 1 / I 2 . (6)

This means that by increasing the voltage several times using a transformer, we reduce the current by the same amount (and vice versa).

Due to the inevitable energy losses due to heat release in the windings and iron core, equations (5) and (6) are satisfied approximately. However, in modern powerful transformers, the total losses do not exceed 2-3%.

In everyday practice we often have to deal with transformers. In addition to those transformers that we use willy-nilly due to the fact that industrial devices are designed for one voltage, and the city network uses another, we also have to deal with car bobbins. The bobbin is a step-up transformer. To create a spark that ignites the working mixture, a high voltage is required, which we obtain from the car battery, after first converting the direct current of the battery into alternating current using a breaker. It is not difficult to understand that, up to the loss of energy used to heat the transformer, as the voltage increases, the current decreases, and vice versa.

Welding machines require step-down transformers. Welding requires very high currents, and the welding machine's transformer has only one output turn.

You probably noticed that the transformer core is made from thin sheets of steel. This is done so as not to lose energy during voltage conversion. In sheet material, eddy currents will play a smaller role than in solid material.

At home you are dealing with small transformers. As for powerful transformers, they are huge structures. In these cases, the core with windings is placed in a tank filled with cooling oil.

Electricity transmission

Electricity consumers are everywhere. It is produced in relatively few places close to sources of fuel and hydro resources. Therefore, there is a need to transmit electricity over distances sometimes reaching hundreds of kilometers.

But transmitting electricity over long distances is associated with noticeable losses. The fact is that as current flows through power lines, it heats them up. In accordance with the Joule-Lenz law, the energy spent on heating the wires of the line is determined by the formula

where R is the line resistance. With a large line length, energy transmission may become generally unprofitable. To reduce losses, you can, of course, follow the path of reducing the resistance R of the line by increasing the cross-sectional area of ​​the wires. But to reduce R, for example, by 100 times, you need to increase the mass of the wire also by 100 times. It is clear that such a large consumption of expensive non-ferrous metal cannot be allowed, not to mention the difficulties of fastening heavy wires on high masts, etc. Therefore, energy losses in the line are reduced in another way: by reducing the current in the line. For example, reducing the current by 10 times reduces the amount of heat released in the conductors by 100 times, i.e., the same effect is achieved as from making the wire a hundred times heavier.

Since current power is proportional to the product of current and voltage, to maintain the transmitted power, it is necessary to increase the voltage in the transmission line. Moreover, the longer the transmission line, the more profitable it is to use a higher voltage. For example, in the high-voltage transmission line Volzhskaya HPP - Moscow, a voltage of 500 kV is used. Meanwhile, alternating current generators are built for voltages not exceeding 16-20 kV, since a higher voltage would require more complex special measures to be taken to insulate the windings and other parts of the generators.

That's why step-up transformers are installed at large power plants. A transformer increases the voltage in the line by the same amount as it decreases the current. The power losses are small.

To directly use electricity in the electric drive motors of machine tools, in the lighting network and for other purposes, the voltage at the ends of the line must be reduced. This is achieved using step-down transformers. Moreover, usually a decrease in voltage and, accordingly, an increase in current occurs in several stages. At each stage, the voltage becomes less and less, and the territory covered by the electrical network becomes wider. The diagram of transmission and distribution of electricity is shown in the figure.

Electric power stations in a number of regions of the country are connected by high-voltage transmission lines, forming a common power grid to which consumers are connected. Such an association is called a power system. The power system ensures uninterrupted supply of energy to consumers regardless of their location.

Electricity use.

The use of electrical power in various fields of science.

The twentieth century became the century when science invades all spheres of social life: economics, politics, culture, education, etc. Naturally, science directly influences the development of energy and the scope of application of electricity. On the one hand, science contributes to expanding the scope of application of electrical energy and thereby increases its consumption, but on the other hand, in an era when the unlimited use of non-renewable energy resources poses a danger to future generations, the urgent tasks of science are the development of energy-saving technologies and their implementation in life.

Let's look at these questions using specific examples. About 80% of the growth in GDP (gross domestic product) of developed countries is achieved through technical innovation, the main part of which is related to the use of electricity. Everything new in industry, agriculture and everyday life comes to us thanks to new developments in various branches of science.

Most scientific developments begin with theoretical calculations. But if in the 19th century these calculations were made using pen and paper, then in the age of STR (scientific and technological revolution) all theoretical calculations, selection and analysis of scientific data, and even linguistic analysis of literary works are done using computers (electronic computers), which operate on electrical energy, which is most convenient for transmitting it over a distance and using it. But if initially computers were used for scientific calculations, now computers have come from science to life.

Now they are used in all areas of human activity: for recording and storing information, creating archives, preparing and editing texts, performing drawing and graphic work, automating production and agriculture. Electronicization and automation of production are the most important consequences of the “second industrial” or “microelectronic” revolution in the economies of developed countries. The development of complex automation is directly related to microelectronics, a qualitatively new stage of which began after the invention in 1971 of the microprocessor - a microelectronic logical device built into various devices to control their operation.

Microprocessors have accelerated the growth of robotics. Most of the robots currently in use belong to the so-called first generation, and are used for welding, cutting, pressing, coating, etc. The second generation robots that are replacing them are equipped with devices for recognizing the environment. And third-generation “intellectual” robots will “see,” “feel,” and “hear.” Scientists and engineers name nuclear energy, space exploration, transport, trade, warehousing, medical care, waste processing, and the development of the riches of the ocean floor among the highest priority areas for using robots. The majority of robots operate on electrical energy, but the increase in electricity consumption by robots is offset by a decrease in energy costs in many energy-intensive production processes due to the introduction of more rational methods and new energy-saving technological processes.

But let's get back to science. All new theoretical developments after computer calculations are tested experimentally. And, as a rule, at this stage, research is carried out using physical measurements, chemical analyzes, etc. Here, the tools of scientific research are diverse - numerous measuring instruments, accelerators, electron microscopes, magnetic resonance imaging, etc. The bulk of these instruments of experimental science are powered by electrical energy.

Science in the field of communications and communications is developing very rapidly. Satellite communications are no longer used only as a means of international communication, but also in everyday life - satellite dishes are not uncommon in our city. New means of communication, such as fiber technology, can significantly reduce energy losses in the process of transmitting signals over long distances.

Science has not bypassed the sphere of management. As scientific and technological progress develops and the production and non-production spheres of human activity expand, management begins to play an increasingly important role in increasing their efficiency. From a kind of art, which until recently was based on experience and intuition, management today has turned into a science. The science of management, the general laws of receiving, storing, transmitting and processing information is called cybernetics. This term comes from the Greek words “helmsman”, “helmsman”. It is found in the works of ancient Greek philosophers. However, its rebirth actually occurred in 1948, after the publication of the book “Cybernetics” by the American scientist Norbert Wiener.

Before the start of the “cybernetic” revolution, there was only paper computer science, the main means of perception of which was the human brain, and which did not use electricity. The "cybernetic" revolution gave birth to a fundamentally different one - machine informatics, corresponding to the gigantically increased flows of information, the source of energy for which is electricity. Completely new means of obtaining information, its accumulation, processing and transmission have been created, which together form a complex information structure. It includes automated control systems (automated control systems), information data banks, automated information databases, computer centers, video terminals, copying and phototelegraph machines, national information systems, satellite and high-speed fiber-optic communication systems - all this has unlimitedly expanded the scope of electricity use.

Many scientists believe that in this case we are talking about a new “information” civilization, replacing the traditional organization of an industrial-type society. This specialization is characterized by the following important features:

· widespread use of information technology in material and non-material production, in the field of science, education, healthcare, etc.;

· the presence of a wide network of various data banks, including public ones;

· turning information into one of the most important factors in economic, national and personal development;

· free circulation of information in society.

Such a transition from an industrial society to an “information civilization” became possible largely due to the development of energy and the provision of a convenient type of energy for transmission and use - electrical energy.

Electricity in production.

Modern society cannot be imagined without the electrification of production activities. Already at the end of the 80s, more than 1/3 of all energy consumption in the world was carried out in the form of electrical energy. By the beginning of the next century, this share may increase to 1/2. This increase in electricity consumption is primarily associated with an increase in its consumption in industry. Main part industrial enterprises runs on electrical energy. High electricity consumption is typical for energy-intensive industries such as metallurgy, aluminum and mechanical engineering.

Electricity in the home.

Electricity is an essential assistant in everyday life. We deal with her every day, and we probably can’t imagine our life without her. Remember the last time your lights were turned off, that is, there was no electricity coming to your house, remember how you swore that you didn’t have time to do anything and you needed light, you needed a TV, a kettle and a bunch of other electrical appliances. After all, if we were to lose power forever, we would simply return to those ancient times when food was cooked over fires and we lived in cold wigwams.

A whole poem can be dedicated to the importance of electricity in our lives, it is so important in our lives and we are so accustomed to it. Although we no longer notice that it is coming into our homes, when it is turned off, it becomes very uncomfortable.

Appreciate electricity!

List of used literature.

1. Textbook by S.V. Gromov “Physics, 10th grade”. Moscow: Enlightenment.

2. Encyclopedic dictionary of a young physicist. Compound. V.A. Chuyanov, Moscow: Pedagogy.

3. Ellion L., Wilkons U.. Physics. Moscow: Science.

4. Koltun M. World of Physics. Moscow.

5. Energy sources. Facts, problems, solutions. Moscow: Science and Technology.

6. Non-traditional energy sources. Moscow: Knowledge.

7. Yudasin L.S.. Energy: problems and hopes. Moscow: Enlightenment.

8. Podgorny A.N. Hydrogen energy. Moscow: Science.