The negative environmental and social consequences of the construction of large hydroelectric power plants force us to take a close look at their possible place in the electric power industry of the future.

The future of hydroelectric power plants

Large hydroelectric power plants perform the following functions in the energy system:

1. power generation;
2. quick matching of generation power with power consumption, frequency stabilization in the power system;
3. accumulation and storage of energy in the form potential energy water in the Earth's gravitational field with conversion into electricity at any time.

Electricity generation and power maneuvering are possible at hydroelectric power plants of any scale. And energy accumulation for a period of several months to several years (for winter and dry years) requires the creation of large reservoirs.

For comparison, a 12 kg car battery with a voltage of 12 V and a capacity of 85 amp hours can store 1.02 kilowatt-hours (3.67 MJ). To store this amount of energy and convert it into electricity in a hydraulic unit with an efficiency of 0.92, you need to raise 4 tons (4 cubic meters) of water to a height of 100 m or 40 tons of water to a height of 10 m.

In order for a hydroelectric power station with a capacity of only 1 MW to operate on stored water for 5 months a year, 6 hours a day on stored water, it is necessary to accumulate at an altitude of 100 m and then pass through a turbine 3.6 million tons of water. With a reservoir area of ​​1 sq. km, the drop in level will be 3.6 m. The same volume of production at a diesel power plant with an efficiency of 40% will require 324 tons of diesel fuel. Thus, in cold climates, storing water energy for the winter requires high dams and large reservoirs.

In addition, on b O In most of the Russian territory in the permafrost zone, small and medium-sized rivers freeze to the bottom in winter. In these parts, small hydroelectric power stations are useless in winter.

Large hydroelectric power plants are inevitably located at a considerable distance from many consumers, and the costs of constructing power lines and energy losses and heating of the wires must be taken into account. Thus, for the Trans-Siberian (Shilkinskaya) hydroelectric power station, the cost of building a power line-220 to the Trans-Siberian with a length of only 195 km (very little for such a construction) exceeds 10% of all costs. The costs of building power transmission networks are so significant that in China the power of wind turbines, which are still not connected to the network, exceeds the power of the entire Russian energy sector east of Lake Baikal.

Thus, the prospects for hydropower depend on the progress of technology and energy production, storage and transmission together.

Energy is a very capital-intensive and therefore conservative industry. Some power plants are still in operation, especially hydroelectric power plants built at the beginning of the twentieth century. Therefore, to assess the prospects for half a century, instead of volumetric indicators of a particular type of energy, it is more important to look at the rate of progress in each technology. Suitable indicators technical progress in generation - efficiency (or percentage of losses), unit power of units, cost of 1 kilowatt of generation power, cost of transmission of 1 kilowatt per 1 km, cost of storage of 1 kilowatt-hour per day.

Energy storage

Storage electricity is a new industry in the energy sector. For a long time, people stored fuel (wood, coal, then oil and petroleum products in tanks, gas in pressure tanks and underground storage facilities). Then mechanical energy storage devices (raised water, compressed air, superflywheels, etc.), among them pumped storage power plants remain the leader.

Outside permafrost zones, the heat accumulated by solar water heaters can already be pumped underground to heat homes in winter. After the collapse of the USSR, experiments on the use of energy ceased solar heat for chemical transformations.

Known chemical batteries have a limited number of charge-discharge cycles. Supercapacitors have much more O greater durability, but their capacity is still insufficient. Magnetic field energy storage devices in superconducting coils are being improved very quickly.

A breakthrough in the spread of energy storage will occur when the price drops to $1 per kilowatt-hour. This will make it possible to widely use types of electricity generation that are not capable of operating continuously (solar, wind, tidal energy).

alternative energy

From technology generation The fastest pace of change is happening in solar energy. Solar panels make it possible to produce energy in any required quantity - from charging a phone to supplying megacities. The energy of the Sun on Earth is a hundred times greater than that of other types of energy combined.

Wind farms have come out of a period of declining prices and are now in a phase of increasing tower size and generator capacity. In 2012, the power of all wind turbines in the world exceeded the power of all power plants in the USSR. However, in the 20s of the 21st century, the possibilities for improving wind turbines will be exhausted and solar energy will remain the engine of growth.

The technology of large hydroelectric power stations has passed its “finest hour”; with each passing decade, fewer and fewer large hydroelectric power stations are being built. The attention of inventors and engineers is turning to tidal and wave power plants. However, tides and large waves are not present everywhere, so their role will be small. In the 21st century, small hydropower plants will still be built, especially in Asia.

Producing electricity from heat coming from the bowels of the Earth ( geothermal energy) is promising, but only in certain areas. Fossil fuel combustion technologies will continue to compete with solar and wind energy for several decades, especially where there is little wind and sun.

Technologies for producing flammable gas are being improved most rapidly by fermentation of waste, pyrolysis or decomposition in plasma). However, municipal solid waste will always require sorting (or better yet, separate collection) before gasification.

TPP technologies

The efficiency of combined cycle power plants exceeded 60%. Converting all gas-fired thermal power plants to combined-cycle power plants (more precisely, gas-steam power plants) will increase electricity production by more than 50% without increasing gas combustion.

Coal and fuel oil thermal power plants are much worse than gas ones in terms of efficiency, the price of equipment, and the amount of harmful emissions. In addition, coal mining requires the most lives per megawatt-hour of electricity. Coal gasification will prolong the existence of the coal industry for several decades, but it is unlikely that the miner's profession will survive into the 22nd century. It is very likely that steam and gas turbines will be replaced by rapidly improving fuel cells in which chemical energy is converted into electrical energy bypassing the stages of obtaining thermal and mechanical energy. In the meantime, fuel cells are very expensive.

Nuclear power

The efficiency of nuclear power plants has grown the slowest over the past 30 years. Improvements to nuclear reactors, which cost several billion dollars each, have been slow, and safety requirements have driven up construction costs. The “nuclear renaissance” did not take place. Since 2006, the world's commissioning of nuclear power plants has been less than not only the commissioning of wind, but also solar. However, it is likely that some nuclear power plants will survive into the 22nd century, although due to the problem of radioactive waste their end is inevitable. Perhaps thermonuclear reactors will also operate in the 21st century, but their small number, of course, “will not make a difference.”

The possibility of realizing a “cold thermonuclear” still remains unclear. In principle, the possibility of a thermonuclear reaction without ultra-high temperatures and without the formation of radioactive waste does not contradict the laws of physics. But the prospects for obtaining cheap energy in this way are very doubtful.

New technologies

And a little fantasy in the drawings. Three new principles of isothermal conversion of heat into electricity are currently being tested in Russia. These experiments have a lot of skeptics: after all, the second law of thermodynamics is violated. So far, one tenth of a microwatt has been received. If successful, batteries for watches and devices will appear first. Then light bulbs without wires. Each light bulb will become a source of coolness. Air conditioners will produce electricity instead of consuming it. There will be no need for wires in the house. It’s too early to judge when fantasy will become reality.

In the meantime, we need wires. More than half of the price of a kilowatt-hour in Russia is accounted for by the cost of construction and maintenance of power lines and substations. More than 10% of the generated electricity goes to heating the wires. “Smart grids”, which automatically manage multiple energy consumers and producers, can reduce costs and losses. In many cases, it is better to transmit direct current than alternating current to reduce losses. In general, you can avoid heating the wires by making them superconducting. However, superconductors that operate at room temperature have not been found and it is unknown whether they will be found.

For sparsely populated areas with high transportation costs, the prevalence and general availability of energy sources is also important.

The most common energy is from the Sun, but the Sun is not always visible (especially above the Arctic Circle). But in winter and at night the wind often blows, but not always and not everywhere. However, wind-solar power plants are already making it possible to significantly reduce the consumption of diesel fuel in remote villages.

Some geologists claim that oil and gas are formed almost everywhere today from carbon dioxide that falls underground with water. It is true that the use of hydraulic fracturing (“fracking”) destroys natural places where oil and gas can accumulate. If this is true, then a small amount of oil and gas (tens of times less than now) can be extracted almost everywhere without harming the geochemical cycle of carbon, but exporting hydrocarbons means depriving oneself of the future.

Diversity natural resources in the world means that sustainable generation of electricity requires a combination different technologies in relation to local conditions. Anyway, unlimited amount Energy on Earth cannot be obtained for both environmental and resource reasons. Therefore, the growth in the production of electricity, steel, nickel and other material things on Earth in the next century will inevitably be replaced by an increase in the production of intellectual and spiritual things.

Igor Eduardovich Shkradyuk

The electric power industry, like other industries, has its own problems and development prospects.

Currently, the Russian electric power industry is in crisis. The concept of "energy crisis" can be defined as a state of tension resulting from a mismatch between needs modern society in energy and energy reserves, including due to the irrational structure of their consumption.

In Russia you can this moment highlight 10 groups the most pressing problems:

• 1). The presence of a large proportion of physically and morally outdated equipment. An increase in the share of physically worn-out assets leads to an increase in accident rates, frequent repairs and a decrease in the reliability of energy supply, which is aggravated by excessive utilization of production capacities and insufficient reserves. Today, equipment wear is one of the most important problems in the electric power industry. At Russian power plants it is very high. The presence of a large proportion of physically and morally obsolete equipment complicates the situation with ensuring the safety of power plants. About one fifth of production assets in the electric power industry are close to or have exceeded their design service life and require reconstruction or replacement. Equipment upgrades are being carried out at an unacceptably low pace and in clearly insufficient quantities (table).
• 2). The main problem of energy is that, along with ferrous and non-ferrous metallurgy, energy has a powerful negative impact on the environment. Energy enterprises generate 25% of all industrial emissions.

In 2000, the volume of emissions of harmful substances into the atmosphere was 3.9 tons, including emissions from thermal power plants - 3.5 million tons. Sulfur dioxide accounts for up to 40% of total emissions, solids - 30%, nitrogen oxides - 24%. That is, thermal power plants are the main cause of the formation of acid residues.

The largest air pollutants are Raftinskaya State District Power Plant (Asbest, Sverdlovsk region) - 360 thousand tons, Novocherkasskaya (Novocherkassk, Rostov region) - 122 thousand tons, Troitskaya (Troitsk-5, Chelyabinsk region) - 103 thousand tons, Verkhnetagilskaya (Sverdlovsk region) - 72 thousand tons.

Energy is also the largest consumer of fresh and sea ​​water, spent on cooling units and used as a heat carrier. The industry accounts for 77% of the total volume of fresh water used by Russian industry.

The volume of wastewater discharged by industry enterprises into surface water bodies in 2000 amounted to 26.8 billion cubic meters. m. (5.3% more than in 1999). The largest sources of water pollution are thermal power plants, while state district power plants are the main sources of air pollution. This is CHPP-2 (Vladivostok) - 258 million cubic meters. m, Bezymyanskaya CHPP (Samara region) - 92 million cubic meters. m, CHPP-1 (Yaroslavl) - 65 million cubic meters. m, CHPP-10 (Angarsk, Irkutsk region) - 54 million cubic meters. m, CHPP-15 and Pervomaiskaya CHPP (St. Petersburg) - a total of 81 million cubic meters. m.

The energy sector also produces a large amount of toxic waste (slag, ash). In 2000, the volume of toxic waste amounted to 8.2 million tons.

In addition to air and water pollution, energy enterprises pollute soils, and hydroelectric power plants have a strong impact on river regimes, river and floodplain ecosystems.

• 3). Tough tariff policy. In the electric power industry, questions have been raised about the economical use of energy and tariffs for it. We can talk about the need to save generated electricity. Indeed, the country currently uses 3 times more energy per unit of production than the United States. There is a lot of work to be done in this area. In turn, energy tariffs are growing at a faster pace. The current tariffs in Russia and their ratio do not correspond to world and European practice. The existing tariff policy has led to unprofitable activities and low profitability of a number of regional energy companies.
• 4). A number of areas are already experiencing difficulties in providing electricity. Along with the Central region, electricity shortages are observed in the Central Black Earth, Volga-Vyatka and North-Western economic regions. For example, in the Central Economic Region in 1995, a huge amount of electricity was produced - 19% of the all-Russian indicators (154.7 billion kW), but it was all consumed within the region.
• 5). Capacity growth is decreasing. This is due to low-quality fuel, worn-out equipment, work to improve the safety of units and a number of other reasons. The underutilization of hydroelectric power plants is due to the low water content of rivers. Currently, 16% of the capacity of Russian power plants has already exhausted its resource. Of these, hydroelectric power stations account for 65%, thermal power plants - 35%. The commissioning of new capacities decreased to 0.6 - 1.5 million kW per year (1990-2000) compared to 6-7 million kW per year (1976-1985).
• 6). The emerging opposition from the public and local authorities to the placement of electric power facilities due to their extremely low environmental safety. Particularly after Chernobyl disaster Many survey work, construction and expansion of nuclear power plants at 39 sites with a total design capacity of 109 million kW were stopped.
• 7). Non-payments, both from electricity consumers and from energy companies for fuel, equipment, etc.;
• 8). Lack of investment, associated both with the current tariff policy and with the financial “opacity” of the industry. The largest Western strategic investors are ready to invest in Russian electric power industry only subject to an increase in tariffs to ensure a return on investment.
• 9). Interruptions in power supply to certain regions, in particular Primorye;
• 10). Low efficiency of energy resources. This means that 57% of energy resources are lost annually. Most losses occur in power plants, in engines that directly use fuel, and in technological processes where fuel serves as a raw material. When transporting fuel, large losses of energy resources also occur.

As for development prospects electric power industry in Russia, then, despite all its problems, the electric power industry has sufficient prospects.

For example, the operation of thermal power plants requires the extraction of a huge amount of non-renewable resources, has a fairly low efficiency, and leads to environmental pollution. In Russia thermal power plants operate on fuel oil, gas, coal. However, on at this stage Regional energy companies with a high share of gas in the fuel balance structure are attractive as a more efficient and environmentally beneficial fuel. In particular, it can be noted that gas-fired power plants emit 40% less carbon dioxide into the atmosphere. In addition, gas stations have a higher installed capacity utilization rate compared to oil and coal stations, have a more stable heat supply and do not incur fuel storage costs. Gas-fired stations are located in better condition than coal and fuel oil, since they were put into operation relatively recently. Gas prices are also regulated by the state. Thus, the construction of thermal power plants using gas as fuel becomes more promising. Also, at thermal power plants it is promising to use dust cleaning equipment with the highest possible efficiency, while the resulting ash can be used as a raw material in the production of building materials.

The construction of a hydroelectric power station, in turn, requires the flooding of a large amount of fertile land, or as a result of water pressure on the earth's crust, a hydroelectric power station can cause an earthquake. In addition, fish stocks in rivers are declining. The construction of relatively small hydroelectric power plants, which do not require major capital investments and operate automatically mainly in mountainous areas, as well as the embankment of reservoirs to free up fertile lands, is becoming promising.

As for nuclear energy, the construction of nuclear power plants has a certain risk, due to the fact that it is difficult to predict the scale of the consequences when the operation of nuclear power units becomes complicated or under force majeure circumstances. Also, the problem of disposal of solid radioactive waste has not been resolved, and the protection system is also imperfect. Nuclear power engineering has the greatest prospects in the development of thermonuclear power plants. This is an almost eternal source of energy, almost harmless to the environment. The development of nuclear power in the near future will be based on the safe operation of existing capacities, with the gradual replacement of first-generation units with the most advanced Russian reactors. The largest expected increase in capacity will occur due to the completion of construction of already started stations.

There are 2 opposing concepts for the further existence of nuclear power in the country.

• 1. Official, which is supported by the President and the Government. Based on the positive features of nuclear power plants, they propose a program for the broad development of the Russian electric power industry.
• 2. Ecological, headed by Academician Yablokov. Proponents of this concept completely reject the possibility of new construction of nuclear power plants, both for environmental and economic reasons.

There are also intermediate concepts. For example, a number of experts believe that it is necessary to introduce a moratorium on the construction of nuclear power plants based on the shortcomings of nuclear power plants. Others suggest that stopping the development of nuclear power could lead to Russia completely losing its scientific, technical and industrial potential in nuclear power.

Based on all negative influences traditional energy on the environment, much attention is paid to studying the possibilities of using non-traditional, alternative energy sources. Practical use have already received the energy of the tides and the internal heat of the Earth. Wind power plants are available in residential settlements in the Far North. Work is underway to study the possibility of using biomass as an energy source. In the future, solar energy may play a huge role.

The experience of developing the domestic electric power industry has produced the following principles of location and operation of enterprises this industry:

• 1. concentration of electricity production at large regional power plants using relatively cheap fuel and energy resources;
• 2. combining the production of electricity and heat for district heating of populated areas, especially cities;
• 3. extensive development of hydro resources, taking into account comprehensive solution problems of electric power industry, transport, water supply;
• 4. need for development nuclear energy, especially in areas with a tense fuel and energy balance, taking into account the safety of using nuclear power plants;
• 5. creation of energy systems that form a single high-voltage network of the country.

At the moment, Russia needs a new energy policy that would be sufficiently flexible and provide for all the features of this industry, including the features of location. As main tasks of Russian energy development the following can be distinguished:

b Reducing the energy intensity of production.

ь Preservation of the integrity and development of the Unified Energy System of Russia, its integration with other energy associations on the Eurasian continent;

b Increasing the power factor of power plants, increasing operating efficiency and ensuring sustainable development of the electric power industry based on modern technologies;

ь Complete transition to market relations, liberation of energy prices, complete transition to world prices.

ь Speedy renewal of the power plant fleet.

b Bringing environmental parameters of power plants to the level of world standards, reducing harmful effects on the environment

Based on these tasks, a “General Scheme for the Location of Electric Power Industry Facilities until 2020” was created, approved by the Government of the Russian Federation. (diagram 2)

The priorities of the General Scheme within the established guidelines for long-term state policy in the electricity sector are:

ь accelerated development of the electric power industry, creation of an economically sound structure of generating capacities and electric grid facilities in it to reliably supply the country's consumers with electric and thermal energy;

b optimization of the fuel balance of the electric power industry through the maximum possible use of the development potential of nuclear, hydraulic, and coal-based thermal power plants and reducing the use of gas in the fuel balance of the industry;

b creation of a network infrastructure that is developing at a faster pace than the development of power plants and ensures the full participation of energy companies and consumers in the functioning of the electric energy and power market, strengthening intersystem connections that guarantee the reliability of mutual supplies of electric energy and power between the regions of Russia, as well as the possibility of exporting electric energy ;

b minimizing specific fuel consumption for the production of electrical and thermal energy through the introduction of modern, highly economical equipment operating on solid and gaseous fuels;

b reduction of the technogenic impact of power plants on the environment through the efficient use of fuel and energy resources, optimization of the industrial structure of the industry, technological re-equipment and decommissioning of obsolete equipment, increasing the scope of environmental protection measures at power plants, implementing programs for the development and use of renewable energy sources.

Based on the results of monitoring to the Government Russian Federation A report on the progress of the implementation of the General Scheme is presented annually. In a few years, it will be clear how effective it is and how much its provisions regarding the use of all prospects for the development of Russian energy are being implemented.

In the future, Russia must abandon the construction of new large thermal and hydraulic stations, which require huge investments and create environmental tension. It is planned to build low- and medium-power thermal power plants and small nuclear power plants in remote northern and eastern regions. On Far East It is planned to develop hydropower through the construction of a cascade of medium and small hydroelectric power stations. New thermal power plants will be built on gas, and only in the Kansk-Achinsk basin is it planned to build powerful condensing power plants due to cheap, open pit mining coal There are prospects for the use of geothermal energy. The areas most promising for the widespread use of thermal waters are Western and Eastern Siberia, as well as Kamchatka, Chukotka, and Sakhalin. In the future, the scale of use of thermal waters will steadily increase. Engagement studies are underway inexhaustible sources energy, such as the energy of the sun, wind, tides, etc., into economic circulation, which will make it possible to ensure savings in energy resources, especially mineral fuels, in the country.

Prospects for the development of thermal power plants and nuclear power plants

At the beginning of the 21st century, the issue of modernization and development of Russian energy became extremely acute, taking into account the following factors:

Wear and tear of equipment of power plants, thermal and electrical networks by the end of the first decade could exceed 50%, which meant that by 2020 depreciation could reach 90%;

Technical economic characteristics energy production and transport are replete with numerous centers of unproductive expenditure of primary energy resources;

The level of equipment of energy facilities with automation, protection and information technology equipment is at a level significantly lower than at energy facilities in Western Europe and the USA;

The primary energy resource at Russian thermal power plants is used with an efficiency not exceeding 32 - 33%, in contrast to countries that use advanced steam power cycle technologies with an efficiency of up to 50% and higher;

Already in the first five years of the 21st century, as the Russian economy stabilized, it became obvious that the energy sector from the “locomotive” of the economy could turn into an “obstacle course.” By 2005, the power supply system of the Moscow region became deficient;

Finding funds for the modernization and development of Russia's energy base in a market economy and energy reform, based on market principles.

Under these conditions, several programs have been created, but their additions and “development” continue.

Here is one of the programs created at the end of the last century (Table 6).

Table 6. Commissioning of power plant capacities, million kW.

Table 7. Investment needs of the electric power industry, billion dollars

The severity of the situation with the energy supply of the Russian economy and social sphere According to experts from RAO UES of Russia, this is illustrated by the emergence of energy-deficient regions (peak consumption loads occur in the autumn-winter period).

This is how the GOELRO-2 energy program came into being. It should be noted that in various sources are given significantly great friend indicators from each other. That is why in the previous tables (Table 6, Table 7) we present the maximum published indicators. Obviously, this “ceiling” level of forecasts can be used as a guide.

The main directions should include:

1. Focus on the creation of thermal power plants using solid fuel. As natural gas prices are brought to world levels, thermal power plants using solid fuels will be economically justified. Modern methods of coal combustion (in a circulating fluidized bed), and then combined cycle coal technologies with preliminary gasification of coal or its combustion in fluidized bed boilers under pressure make it possible to make thermal power plants using solid fuel competitive in the “market” of thermal power plants of the future.

2. The use of “expensive” natural gas at newly constructed thermal power plants will be justified only when using combined cycle plants, as well as when creating mini-thermal power plants based on gas turbine units, etc.

3. Technical re-equipment of existing thermal power plants will remain a priority due to increasing physical and moral wear and tear. It should be noted that when replacing components and assemblies, it becomes possible to introduce advanced technical solutions, including in matters of automation and computer science.

4. The development of nuclear energy in the near future is associated with the completion of the construction of high-readiness units, as well as work to extend the service life of nuclear power plants for an economically feasible period of time. In the longer term, capacity commissioning at nuclear power plants should be carried out by replacing dismantled units with new generation power units that meet modern safety requirements.

The future development of nuclear energy is determined by the solution of a number of problems, the main of which are achieving complete safety of existing and new nuclear power plants, closing nuclear power plants that have exhausted their service life, and ensuring the economic competitiveness of nuclear energy in comparison with alternative energy technologies.

5. An important direction in the electric power industry for modern conditions is the development of a network of distributed generating capacities through the construction of small power plants, primarily small-capacity cogeneration plants with combined cycle gas turbine units and gas turbine units

Despite the rapid development of non-traditional energy industries in recent decades, the majority of electricity produced in the world still accounts for the share of energy produced at thermal power plants. At the same time, the increasing demand for electricity every year has a stimulating effect on the development of thermal energy. Power engineers all over the world are working towards improving thermal power plants, increasing their reliability, environmental safety and efficiency.

TASKS OF THERMAL POWER ENGINEERING

Thermal power engineering is a branch of energy that focuses on the processes of converting heat into other types of energy. Modern thermal power engineers, based on the theory of combustion and heat transfer, study and improve existing power plants, study the thermophysical properties of coolants and strive to minimize the harmful environmental impact of the operation of thermal power plants.

POWER INSTALLATIONS

Thermal energy is unthinkable without thermal power plants. Thermal power plants operate according to the following scheme. First, organic fuel is fed into the furnace, where it is burned and heats the water passing through the pipes. Water, when heated, is converted into steam, which causes the turbine to rotate. And thanks to the rotation of the turbine, the electric generator is activated, thanks to which electric current is generated. Thermal power plants use oil, coal and other non-renewable energy sources as fuel.

In addition to thermal power plants, there are also installations in which thermal energy turns into electric without the auxiliary help of an electric generator. These are thermoelectric, magnetohydrodynamic generators and other power plants.

ENVIRONMENTAL PROBLEMS OF THERMAL POWER ENGINEERING

The main negative factor in the development of thermal power engineering has been the harm that thermal power plants cause to the environment during their operation. When fuel burns, a huge amount of harmful emissions are released into the atmosphere. These include volatile organic compounds, solid ash particles, gaseous oxides of sulfur and nitrogen, and volatile compounds of heavy metals. In addition, thermal power plants heavily pollute water and spoil the landscape due to the need to organize places for storing slag, ash or fuel.

Also, the operation of thermal power plants is associated with greenhouse gas emissions. After all, thermal power stations emit a huge amount of CO 2, the accumulation of which in the atmosphere changes the thermal balance of the planet and causes the greenhouse effect - one of the most pressing and serious environmental problems of our time.

That is why the most important place in modern developments of thermal energy should be given to inventions and innovations that can improve thermal power plants towards their environmental safety. We are talking about new technologies for purifying fuel used by thermal power plants, the creation, production and installation of special cleaning filters at thermal power plants, and the construction of new thermal power plants, originally designed taking into account modern environmental requirements.

DEVELOPMENT PROSPECTS

Thermal power devices are, and will continue to be, the main source of electrical energy for humanity for a very long time. Therefore, thermal power engineers around the world continue to intensively develop this promising branch of energy. Their efforts are primarily aimed at increasing the efficiency of thermal power plants, the need for which is dictated by both economic and environmental factors.

Strict requirements of the world community for the environmental safety of energy facilities stimulate engineers to develop technologies that reduce emissions from thermal power plants to maximum permissible concentrations.

Analysts claim that modern conditions are such that thermal power plants operating on coal or gas will be promising in the future, therefore it is in this direction that thermal power engineers around the world are putting the most effort.

The dominant role of thermal power engineering in meeting the world's human needs for electricity will continue long time. Indeed, despite the desire of developed countries to switch to energy sources that are more environmentally safe and accessible (which is important in light of the approaching crisis of fossil fuel depletion) as soon as possible, a quick transition to new methods of producing energy is impossible. This means that the thermal power industry will continue to actively develop, but, of course, taking into account new requirements for the environmental safety of the technologies used.

Thermal power plants (TPPs) running on fossil fuels have remained the mainstay for many decades. industrial source electricity, ensuring positive dynamics of global economic growth. According to the IEA (“Key World Energy Statistics 2007”), all thermal power plants in the world provided the production of 12,149 billion kWh of electrical energy in 2005, covering two-thirds of its global consumption. The main sources of primary energy for thermal power plants are fossil fuels - coal, natural gas and oil. The main one is coal, which provides 40.3% of current global electricity production. Natural gas accounts for 19.7% of global electricity production, oil – 6.6%.

According to IEA forecasts (World Energy Outlook 2006, IEA), the global demand for electricity by 2030 will more than double the current level and reach 30116 billion kWh (Fig. 6.1). If the current trends of moderate development of nuclear energy, as envisaged in the IEA forecast, continue, the share of thermal power plants in total electricity production will increase and slightly exceed the current level. If the 2006 IAEA forecast is implemented, which assumes a renaissance of nuclear energy with an increase in its share in global electricity production in 2030 to 25% against 11.7% according to the IEA forecast, thermal power plants will still cover more than half of humanity’s energy needs. electrical energy.

In accordance with the IEA forecast (World Energy Outlook 2006, IEA), coal will remain the main type of fuel for thermal power plants (Fig. 6.2). The dominant role of coal-fired thermal power plants will remain in the implementation of the IAEA scenario.

Proven reserves of fossil organic fuel are sufficient for sustainable operation of thermal energy for many decades. According to modern data, the supply of the world community's needs for oil and natural gas, based on proven recoverable resources, is estimated at 50–70 years, for coal - more than 200 years. Over the past 20–30 years, these periods have been constantly adjusted upward as a result of the rapid pace of geological exploration and the improvement of technologies for extracting proven reserves.

Most important issue The future development of thermal energy in the world remains, as before, further technological improvement of thermal power plants in order to increase the efficiency, reliability and environmental friendliness of the production of electrical and thermal energy.

Increasing the efficiency of thermal power plants is a natural process dictated by the need to compensate for the constantly growing costs of the fuel cycle. Exploration, development and exploitation of new oil, gas and coal deposits, as well as the development of existing ones, are increasingly expensive, and maintaining acceptable prices for electrical energy requires an adequate and rapid increase in efficiency. TPP. In addition, the need to improve efficiency is also dictated by environmental considerations.

Direct environmental hazards at the local and regional levels are created by atmospheric emissions of harmful substances with combustion products of organic fuel - gaseous oxides of sulfur and nitrogen, solid particles (ash), volatile organic compounds (in particular benzopyrene), volatile compounds heavy metals(mercury, vanadium, nickel). Thermal power plants also pose a certain environmental hazard as large-scale polluters of water basins. Modern thermal power plants account for up to 70% of industrial water intake from natural sources, which makes up a significant part of the water resources of many countries experiencing problems with water supply. fresh water. It is also impossible not to note the significant influence of thermal energy on direct and indirect changes in local landscapes in the processes of burial of ash and slag, extraction, transport and storage of fuel.

Almost all factors of the negative impact of thermal power plants on the environment must be reduced to environmentally friendly safe level, both due to increased efficiency and as a result of the implementation of known and newly developed environmental technologies, in particular technologies for trapping harmful substances in technological processes of fuel preparation, its combustion and removal of gas and solid combustion products, reagent-free water treatment technologies etc. These measures require significant costs. However, as forecasting studies show, proper organization of the consistent implementation of increasingly effective, albeit more expensive, environmental measures as the capabilities of the global economy grow will avoid the excessive impact of these costs on the price of electrical energy.

Along with local influences, thermal power plants around the world are increasingly increasing their contribution to global environmental processes, leading, in particular, to climate change on the planet. Thermal energy is one of the main sources of emissions of water vapor, carbon dioxide, dust and other components into the atmosphere - absorbers of long-wave infrared radiation from the earth's surface. An increase in the concentration of absorbing components of the atmosphere causes the so-called greenhouse effect - heating of the Earth's surface by short-wave solar radiation due to worsening conditions for its radiative cooling due to the shielding effect of the absorbing components of the atmosphere.

The operation of thermal power plants is accompanied by emissions of many greenhouse gases, the main of which are water vapor and carbon dioxide produced during the combustion of all types of hydrocarbon organic fuels. The release of water vapor from coal-fired thermal power plants does not lead to a noticeable increase in its concentration in the atmosphere, since it is negligible compared to the natural evaporation of water. In addition, a significant part of emissions from thermal power plants is condensed and removed with sediment. At the same time, the products of coal combustion and anthropogenic emissions of carbon dioxide, unlike steam, accumulate in the atmosphere, contributing to the development of the greenhouse effect. The annual emission of CO 2 by all thermal power plants in the world is approaching 10 billion tons of carbon dioxide, accounting for about 30% of all anthropogenic greenhouse gas emissions into the planet's atmosphere. Emissions of water vapor become noticeable when thermal power plants operate on natural gas, but at the same time specific emissions of CO 2 decrease.

It is generally accepted that the strengthening of the greenhouse effect, caused by an increase in the concentration of carbon dioxide in the atmosphere, leads to an increasingly noticeable increase in the temperature of the planet, which may have global catastrophic consequences in the near future. This statement is not supported by everyone, but due to the significance of the threat, it is considered officially accepted.

On February 16, 2005, the Kyoto Protocol to the UN Framework Convention on Climate Change came into force, with the goal of reducing emissions of gases that contribute to global warming. The protocol, signed in 1997 by 159 countries at an international summit held in Kyoto under the auspices of the UN, determined that 39 industrialized countries of the world undertake to reduce emissions of carbon dioxide and five other substances, the presence of which in the atmosphere affects climate change on the planet. The countries that signed the protocol pledged to reduce emissions of harmful gases into the atmosphere by 5.2% by 2012 compared to 1990 levels. The document has been ratified by 125 countries around the world, which account for more than 55% of total greenhouse gas emissions. The implementation of the agreement became possible after the ratification of the protocol in Russia, which accounts for 17.4% of greenhouse gas emissions. At the same time largest countries world - the United States, which produces 36% of global carbon emissions, as well as India and China, have not joined the protocol, although these countries are also working to reduce greenhouse gas emissions. In particular, the United States has established a five-year preferential tax period for renewable energy sources and energy saving technologies in the amount of 3.6 billion dollars. The planned volume of annual funding for activities aimed at preventing climate change in the United States amounted to $5.8 billion, including $3 billion. for the development of new technologies and another 2 billion for scientific research in this area.

However, efforts undertaken under the Kyoto Protocol have not yet produced the desired effect. According to the IEA, over the past decade, greenhouse gas emissions not only have not decreased, but have increased by more than 20%. When saving modern trends global development, greenhouse gas emissions will increase by another 2.5 times by 2050.

The results of forecast studies show that the growth in electricity production in developing countries will occur mainly due to the primary use of their own coal reserves - the primary energy carrier that produces the largest CO 2 emissions per unit of energy received.

For countries that do not have sufficient reserves, the growth of thermal energy based on local types of organic fuel, plant biomass, industrial and household waste is predicted.

Projected external conditions The future development of the world's thermal power industry is determined by the following long-term priorities for its technological growth:

• a significant increase in the efficiency and environmental safety of thermal energy using solid fuels, ensuring in the future close to zero emissions of harmful substances;
• a significant increase in the efficiency of natural gas power generation;
• development of combined production of electrical energy and other types of energy;
• development of cost-effective technologies for producing electrical energy from substandard and renewable organics;
• development of technologies for capturing and storing greenhouse gases.

As of 2003, the total installed capacity of thermal power plants in the world was 2591 GW, of which coal-fired thermal power plants - 1119 GW, natural gas

1007 GW, oil – 372 GW. About 11% of the world's thermal power plant fleet has served for more than 40 years, about 60% for more than 20 years. The average efficiency of thermal power plants in the world is slightly higher than 35%.

To ensure the predicted levels of electrical energy production, the total installed capacity of thermal power plants must be increased to 4352 GW by 2030. In accordance with the IEA forecast scenario, this will require the commissioning of 1,761 GW of new thermal power plants and the reconstruction of more than 2,000 GW of existing capacity.

In accordance with modern forecasts, taking into account the provision of fuel resources, improvement of technologies, economic and environmental consequences of increased emissions of pollutants, the capacity of thermal power plants using coal and natural gas will develop at the fastest pace in the coming decades.

Therefore, the greatest attention is paid to the improvement and implementation of new efficient technologies for thermal power plants using solid and gaseous fuels. Along with this, research work is being developed aimed at developing and implementing promising technologies for maximum capture of harmful substances, including greenhouse gases, from fuel combustion products, ensuring the environmental safety of thermal power plants.

Thermal power generation using natural gas

Promising technologies for thermal power plants running on natural gas, oriented for use in large-scale power generation, are most intensively developing in the following main areas: High-temperature gas turbine units (GTU).

• Combined or combined cycle gas plants (CCGTs), combining gas turbine and steam turbine cycles.
• High temperature fuel cells.
• Hybrid installations based on a combination of CCGT units with high-temperature fuel cells.

The main objectives of research and development in the field of gas turbine technologies are increasing power, efficiency. and environmental performance of gas turbines, the creation of “flexible” gas turbine units operating on gasification products of various types of fuel, gas turbines for operation as part of large combined and hybrid units. The main directions for improving gas turbines include increasing the initial gas temperatures in front of the gas turbine through the use of more efficient high-temperature construction materials and creating more effective systems thermal protection of high-temperature elements of gas turbine plants while simultaneously improving the processes of environmentally friendly fuel combustion. To date, power-generating gas turbine plants for initial temperatures of 1260–1400°C with efficiency have been industrially developed. 35–36.5%. At the stage of demonstration and pilot industrial samples there are gas turbine units of a new generation based on metal ceramics with an operating temperature above 1500°C and efficiency. at the level of 40% and above.

An important area of ​​use of highly efficient power gas turbines is their use as part of powerful combined cycle power units of thermal power plants and combined heat and power plants. Operating combined cycle gas turbine units (CCGTs), which implement a high-temperature gas turbine Brayton cycle with heat removal into a double-circuit steam turbine Rankine cycle (two-pressure cycle), ensure operational electrical efficiency. at the level of 48–52%. In particular, Russia’s first cogeneration CCGT units with a capacity of 450 MW, installed at the North-West CHPP in St. Petersburg, operate according to this scheme. They have a calculated efficiency. net 51%, actual operating efficiency in power control mode – 48–49%.

Prospects for further improvement of binary combined cycle gas plants are determined by increasing the efficiency of heat transfer from gas turbine exhaust gases to the steam turbine cycle and reducing losses during steam condensation. The traditional direction for solving these problems is associated with increasing the number of circuits (pressure stages) of the steam turbine cycle. Efficiency has been achieved in the three-circuit unit of the Yokohama TPP (Japan). at 55%.

The use of more efficient gas turbines will improve efficiency. CCGT units with two- and three-circuit circuits up to 60%, the use of water cooling and other circuit solutions - up to 61.5–62% and more.

More distant prospects for increasing efficiency Thermal power plants using natural gas are associated with the creation of hybrid installations, which are a combination of high-temperature electrochemical current sources ( fuel cells) with a steam-gas plant.

High-temperature fuel cells (HF), solid oxide fuel cells (SOFC) or molten carbonate fuel cells (MCFC), operating at temperatures of 850 and 650°C, serve as heat sources for the CCGT. To date, samples of high-temperature energy fuel cells with a unit power from 200 kW to 10 MW have been created, suitable for this purpose. High temperature fuel cells can run on hydrogen and/or synthesis gas (a mixture of hydrogen and carbon monoxide). To obtain it, the process of reforming (steam reforming) of natural gas is used. To obtain hydrogen from synthesis gas, a catalytic oxidation process is used carbon monoxide followed by removal of CO 2 . These processes are widely used in the nitrogen industry.

During the implementation of the US scientific and technical program “Vision-21”, efficiency was obtained on a demonstration hybrid installation with a capacity of about 20 MW. at 60%. The launch of a hybrid plant with efficiency is planned for 2010. at 70%. In the longer term, efficiency is expected to be achieved. at 75% with creation power plants with a capacity of up to 300 MW or more (Fig. 6.3). By 2012–2015 It is planned to create all the necessary technological components for this.

In the field of small-scale energy (see section 4.4), cogeneration technologies based on gas engines are of greatest interest internal combustion and electrochemical current sources (fuel cells). To date, pilot batches of low- and medium-temperature cogeneration fuel cells with proton-exchange membrane (PEFC) and phosphate-acid (PAFC) are being used in the USA, Japan, and Europe. These units are silent, more efficient and environmentally friendly than gas internal combustion engines. The prospects for large-scale use of cogeneration fuel cells are associated with a decrease in their unit cost.

Promising coal energy technologies

Among the intensively developed areas of environmentally friendly use solid fuel, expected to industrial implementation in the short term (until 2010) and long term, these include steam turbine thermal power plants with supersupercritical steam pressure (parameters); combined cycle thermal power plants on coal; hybrid combined cycle thermal power plants.

Work on the creation of power units for super-supercritical steam parameters was started in the USA and USSR in the middle of the last century. The creation of SSKD power units is based on known methods increasing thermal efficiency Rankine cycle due to the transition to higher operating temperatures and steam pressure in front of the turbine. The application of these measures in practice is limited by the strength characteristics of the materials used, as well as the increasing cost of installation. There is a technical and economic optimum of steam temperatures and pressures, determined by the properties of the power plant materials and fuel prices. In the second half of the last century, these conditions were met by the supercritical Rankine cycle with a single intermediate superheat of steam, an initial pressure of 23.5 MPa, and a temperature of primary and secondary superheat of 540 ° C. In recent years, advances in materials science have made it possible to further improve the parameters of the Rankine cycle.

In Denmark and Japan, coal-fired power units with a capacity of 380–1050 MW with fresh steam pressure of 24–30 MPa and superheating up to 580–610 °C have been built and are successfully operating. Among them there are blocks with double reheating up to 580°C. Efficiency the best Japanese blocks are at the level of 45–46%, Danish ones operating on cold circulating water with deep vacuum are 2–3% higher. In Germany, brown coal power units with a capacity of 800–1000 MW with steam parameters up to 27 MPa, 580/600°C and efficiency were built. up to 45%.

Work on a power unit with super-supercritical steam parameters (pressure 30 MPa, temperature 600/600°C) has been resumed in Russia. They confirmed the reality of creating such a unit with a capacity of 300–525 MW with efficiency. about 46% in the coming years.

After a long break, work aimed at introducing super-supercritical steam parameters in the USA has been resumed. They concentrate mainly on the development and testing of the necessary materials capable of ensuring the operation of equipment at steam temperatures up to 870 ° C and pressures up to 35 MPa.

In countries European Union with large group Energy and mechanical engineering companies are developing an improved pulverized coal power unit SSKD with a fresh steam pressure of 37.5 MPa, a temperature of 700°C and double reheating to 720°C at pressures of 12 and 2.35 MPa. At a condenser pressure of 1.5–2.1 kPa, efficiency block may reach 53–54%. Commissioning is scheduled after 2010. By 2030, efficiency is expected to be achieved. up to 55% at steam temperatures up to 800°C.

The importance of significantly increasing the efficiency of thermal power plants through further improvement of proven technologies is shown in Table 6.1 using the example of three thermal power plants built in Germany in 2002–2004.

Promising developments of coal-fired combined cycle gas plants carried out by many countries. The greatest progress is expected in two areas of work: coal gasification and direct combustion of coal under pressure. Scientific and technical development of coal-fired CCGT units is intensively carried out in the USA within the framework of the Clean Coal Technologies program for

11 projects with a funding volume of $2.9 billion. The capacity of the installations involved in the projects exceeds 2.2 GW. Five projects are devoted to CCGT units with coal combustion under pressure, 4 – CCGT units with coal gasification, 2 – to promising combustion technologies using internal combustion engines.

The operating cycle of a CCGT with gasification includes air or steam-air gasification of coal under pressure created by the compressor of the gas turbine unit, purification of the generator gas from sulfur compounds and solid particles, subsequent combustion of the generator gas in the combustion chamber of a combined cycle gas plant operating in the same way as with natural gas. Today, about 400 large industrial gasification plants with a total capacity of 46 GW are in operation in the world. Half of them run on coal. However, the implementation of CCGTs based on them is associated with certain difficulties. They are due, on the one hand, to the lower quality of thermal coals, which usually contain a large amount of mineral inclusions, sulfur and resins, and on the other hand, to the high requirements for the purity of the generator gas under the conditions of chemical corrosion and mechanical erosion of a gas turbine unit. In addition, significantly higher requirements than in industry are placed on the energy efficiency of the processes for producing and purifying generator gas, as well as on the weight and size characteristics of gas generators. These circumstances create significant difficulties in the practical implementation of coal-fired CCGT units with acceptable efficiency indicators. and unit cost.

Table 6.1 Increasing the efficiency of thermal power plants by improving proven technologies using the example of three thermal power plants built in Germany in 2002–2004

Note. The year of efficiency achievement is indicated in brackets.

However, given the significant medium- and long-term prospects associated with the further application of CO 2 capture technologies, these difficulties seem surmountable.

Design studies of various CCGT schemes with gasification of coal of the most common grades were carried out in the USSR at the turn of the 1990s. They showed the possibility of creating a CCGT unit with a unit capacity of 250 - 650 MW with acceptable environmental characteristics and efficiency. 38–45% based on the existing gas turbine engine base at that time.

In the USA, there are 4 pilot industrial CCGT installations with coal gasification, including the Polk CCGT with a capacity of 250 MW, Puyertollano (350 MW), Bugenno (250 MW), Wabash River, showing the possibility of obtaining p.d. at the level of 46–48%, which is also typical for SKD power units. The actual average specific heat consumption (based on the higher calorific value) of the Polk CCGT is 9864 kJ/kWh, the Wabash River CCGT is 9400 kJ/kWh, which corresponds to the efficiency. according to the lower calorific value at the level of 38 and 40%, respectively. In 2010, it is planned to commission the Mesaba CCGT unit (Minnesota) with coal gasification with a capacity of 531 MW and an efficiency of 41.7%.

A project for the construction of a demonstration CCGT unit with a capacity of 500 MW is under consideration, which involves obtaining initial efficiency. 44.4%, bringing it to 46%. In the future, as we move to high-temperature gas turbine units using synthesis gas, the efficiency will increase. CCGT with coal gasification can be increased to 53%.

The greatest industrial development of CCGT units with gasification of solid fuels was achieved in Italy in relation to the use of petroleum coke, a product of large-scale oil refining. There are 3 CCGT units with petroleum coke gasification at the thermal power plants “Isab” (520 MW), “Sarlux” (550 MW) and “Falconara” (280 MW). In 2005, it was planned to commission a CCGT unit at the Ferrera Erbognone thermal power plant with a capacity of 250 MW near the Sannazaro oil refinery. Another 10 CCGT units have been commissioned or are being built at chemical plants in Italy.

Coal gasification technology is believed to provide the most versatile and clean way to convert coal into electricity, hydrogen and other valuable energy products. It is gasification that can become the basis for the creation of new generation power plants for the coming decades.

When developing units and components of promising gasification CCGT units using low-grade thermal coals, carried out today in several large-scale projects, not only immediate but also more distant goals are pursued. These include, in particular, the creation, based on CCGT with gasification, of hybrid thermal power plants, including high-temperature fuel cells, as well as energy technology installations that combine the generation of electricity with the production of high-quality transport fuel from synthesis gas, emission-free power plants that implement capture, binding and disposal carbon dioxide and dramatically improve fuel efficiency.

Currently, fuel cells with a capacity of 200 kW - 1 MW have been created, capable of operating on synthesis gas and/or hydrogen obtained from synthesis gas.

In coal-fired CCGT units, the technology of direct combustion of coal in a furnace under pressure is used. Air is supplied to the coal furnace by a gas turbine compressor with a pressure of 1–1.5 MPa; the combustion products, after being cleaned from fly ash, expand in the gas turbine and produce useful work. The combustion heat of coal and the heat of gas turbine exhaust gases are used in the steam turbine cycle. The main advantages of CCGT units with coal combustion under pressure are due to the possibility of obtaining high environmental characteristics of thermal power plants due to the proper organization of the combustion process. The combustion temperature of coal in such installations is maintained at the level

800–900°C, which allows maintaining an acceptably low rate of nitrogen oxide formation. In addition, the combustion process is accompanied by chemical binding of sulfur compounds as a result of their reaction with dolomite, which significantly reduces their presence in the exhaust gases of the installation. The main difficulties in the practical implementation of installations of this type are associated with the prevention of mechanical erosion of the gas turbine, which occurs due to the presence of solid fly ash particles in the flue gases, as well as with a decrease in the weight and size characteristics of furnaces operating under pressure.

The experience gained during the long-term operation of several thermal power plants of this type with a capacity of about 20 MW has confirmed the high environmental and economic characteristics of these installations. A typical example of a coal combustion plant under pressure is, in particular, a thermal power plant operating in Stockholm, Sweden. The thermal power plant uses the process of burning a pre-prepared paste from a moistened mixture of coal with dolomite, squeezed out through profile holes in the bottom of the boiler furnace with a diameter of about 20 m. The heat of combustion of the fuel is perceived by submersible heat exchangers of the steam turbine circuit. Flue gases, after preliminary cleaning from fly ash in high-temperature bag filters, enter the gas turbine. The exhaust gases undergo additional purification from solid particles in bag filters, after which they are discharged into the chimney. Average electrical efficiency installations is 45%. Significant erosive wear of the gas turbine was not recorded.

The main difficulty in extending the described technology to power units of thermal power plants with a capacity of 100–300 MW and above is due to the unacceptable increase in the weight and size characteristics of the furnace in terms of strength, which requires intensification of the coal combustion process. The highest speed of this process is ensured by the combustion of a coal-dolomite mixture in a pressurized fluidized bed (FBL). It is this coal-fired CCGT technology that is considered today as the most promising. CCGT units with pressure boosters (PFBC technology), as noted above, are being intensively studied in the USA at five demonstration units.

The advantages of CCGT with CSD include completeness (> 99%) of combustion of various types of coal, high heat transfer coefficients and small heating surfaces, low (up to 850°C) combustion temperatures and, as a result, low (less than 200 mg/m 3 ) NO X emissions, absence of slagging, the possibility of adding sorbent (limestone, dolomite) to the layer and binding 90–95% of the sulfur contained in coal in it.

Quite high efficiency (40–42% in condensing mode) is achieved in a CCGT unit with a pressure compressor already at moderate powers (about 100 MWel) and subcritical steam parameters. Due to the small size of the boiler and the lack of desulphurization, the area occupied by a CCGT with a CSD is small. Block-packaged supply of their equipment and modular construction with a reduction in its cost and time are possible. These circumstances determine the possibility of using this technology in the reconstruction of existing coal-fired power units.

The technology of CCGT units with pressure boosters is simpler and more familiar to power engineers than gasification plants, which are complex chemical production. Various combinations of both technologies are possible. Their goal is to simplify gasification and gas purification systems and reduce their characteristic losses, as well as increase the temperature of gases in front of the turbine and gas turbine power in schemes with pressure boosters.

Hybrid solid fuel plants are a combination of coal gasification CCGT units with a high-temperature fuel cell running on hydrogen or synthesis gas from solid fuels (Fig. 6.4). The operating principle of hybrid installations using coal is the same as those using natural gas. The only difference is in the method of producing hydrogen and/or synthesis gas for fuel cells. In coal hybrid installations, the source fuel must be subjected to gasification to produce hydrogen or synthesis gas, and in natural gas installations, reforming (steam reforming) to produce the same gases. Further differences lie in the purification processes of the resulting products. For coal hybrid plants, for obvious reasons, they are more complicated and less efficient than for gas ones.

The efficiency of hybrid plants in comparison with other coal combustion technologies is shown in Fig. 6.5.

Carbon dioxide removal and capture technologies

Complete environmental friendliness of thermal energy can be ensured by capturing and storing carbon dioxide. The possibilities of creating appropriate technologies are already being intensively studied in many countries around the world. Capture technologies represent the third, most radical way to combat climate warming, along with the other two - increasing efficiency. and carbon removal from fossil fuels. The term carbon removal refers to capturing carbon from energy plants and sequestering it in natural sinks such as forests and farms. Carbon dioxide captured from anthropogenic emissions can be buried underground in geological formations or in the oceans, and can be processed into fuels, harmless solids, or useful products.

The main areas of work on the complex problem of CO 2 capture and disposal, being developed in the USA, include: development of processes for CO 2 capture with the formation of solid hydrates at low temperatures And high pressures; in a vortex tube; dry sorbent based on sodium.

In geology, this is complex research and demonstration on an industrial scale of CO 2 burial in deep, undeveloped coal seams; displacement of natural gas from voids when filling with CO 2; optimal geological conditions for the accumulation of CO 2 in saline porous aquifers of the USA; new methods of injecting CO 2 into salt-bearing formations; chemical fixation of CO 2 in deep salinity formations in the US Midwest.

Promising concepts: gas extraction from landfills; CO 2 mineralization; membrane technologies for separating CO 2 from a gas mixture; selective high-temperature ceramic membranes for carrying out gas reforming reactions with simultaneous CO 2 separation; converting CO 2 into biomass using algae.

Particular attention to preventing CO 2 emissions should be paid when improving coal technologies. In the United States, it is planned to create coal-fired energy complexes capable of competing with thermal power plants running on natural gas. It is advisable to construct them in stages: the first stage is a promising environmentally friendly CCGT unit with gasification; the second stage is the introduction of a CO 2 removal and transportation system; the third stage is the organization of the production of hydrogen or clean transport fuel.

In addition, schemes for new installations are being intensively developed where carbon dioxide is used as a working fluid, ultimately turning into a liquid to be buried. Such a thermal power plant may be based on the following processes:

• gasification of a coal-water suspension with the addition of hydrogen and the production of CH 4 and H 2 O. Coal ash is removed from the gasifier, and the steam-gas mixture is purified;
• carbon, which has passed into a gaseous state, in the form of CO 2 is bound by calcium oxide in the reformer, where purified water is also supplied. The hydrogen generated in it is used in the hydrogasification process and, after fine purification, is supplied to a solid oxide fuel cell to generate electricity;
• at the third stage, the CaCO 3 formed in the reformer is calcined using the heat released in the fuel cell and the formation of CaO and concentrated CO 2, suitable for further processing;
• the fourth stage is the transformation chemical energy hydrogen into electricity and heat, which is returned to the cycle. CO 2 is removed from the cycle and mineralized in carbonization processes of minerals such as,
• for example, magnesium silicate, which is ubiquitous in nature in quantities orders of magnitude greater than coal reserves. The end products of carbonization can be buried in mined-out mines.

Efficiency conversion of coal into electricity in such a system will be about 70%. With the total cost of CO 2 removal equal to 15–20 dollars. US per ton, it will cause an increase in the price of electricity by approximately $0.01. US/kWh.

Thermophysical problems in thermal power engineering that require further research and development

The rapid growth of electricity needs in the 21st century, the crisis state of the environment, and the technological problems that must be solved to meet these needs, based on modern criteria for a sharp increase in energy efficiency, cost reduction and minimization of the impact on the environment, require a significant expansion of scientific research and development in thermal power engineering. Research, development and design work in the thermal power industry should be aimed at creating highly efficient and environmentally friendly thermal power plants using advanced technologies and energy equipment, ensuring the solution of the following tasks: increasing the efficiency of energy supply by increasing its reliability and reducing the cost of electricity production; maximum reduction of harmful emissions from thermal power plants into the environment; increased productivity and improved working conditions; reduction of costs for repair and restoration work.

Important areas of scientific and technological progress in thermal power engineering are:

• creation of new generations of power equipment;
• reconstruction and modernization of existing equipment;
• transition from the concept of extending the service life of equipment to the concept of resource management based on modern combined methods and criteria with joint consideration of indicators of its reliability and efficiency;
• security required level industrial safety energy equipment.
• highly efficient production of electricity and heat based on the use of combined cycle and gas turbine plants, technical re-equipment and further development of thermal power plants to increase their economic and environmental efficiency, reliability, maneuverability and controllability;
• development of environmentally friendly coal technologies based on the use of boilers with a circulating fluidized bed, the use of water-coal suspensions, various coal gasification schemes, etc.;
• creation of effective gas cleaning systems for power equipment;
• complex automation of equipment of units and power plants;
• solving scientific and technical problems related to the development of equipment for supercritical steam parameters, technologies for obtaining cheap equipment for fuel cells, electrical energy storage systems;
• Creation small installations for the combined production of electrical energy and heat (cogeneration) using piston engines, gas turbines (CHP of low and medium power, mini-CHP).

The growth of the technical level of thermal power engineering, the development of supercritical and supersupercritical steam parameters, the increase in unit capacities of units and power units are accompanied by an increase in the calculated heat flux densities perceived by both radiation and convective heating surfaces, and necessitate the intensification of combustion processes, as well as the processes of generation and superheating of steam. It is necessary to intensify heat transfer so that, with an increase in the unit power of installations, acceptable weight and size characteristics of the equipment are maintained. Therefore, the issues of studying radiation heat transfer in furnaces and gas radiation, intensification convective heat exchange in bundles of pipes, as well as the thermal state of heating surfaces under conditions of slagging and intensive entrainment of ash deposits, work on heat transfer during boiling water in pipes, studies of heat transfer of supercritical coolant parameters, critical heat flows.

Currently, the role of high-temperature gas turbine and combined cycle plants in the energy sector is increasing. Therefore, the development of cooling systems for gas turbines, research into turbulent heat transfer in turbine grids and on the plate, including heat transfer under conditions of coolant injection, as well as research into various cooling systems, the use of water vapor as a promising coolant, and optimization of cooling schemes remain relevant.

Strategic directions for the development of the domestic thermal power industry are associated with solving a whole range of problems, including in the field of power engineering. These include:

• creation of domestic highly efficient gas turbine units with a capacity of up to 180 MW for high initial gas temperatures with the aim of widespread introduction of combined cycle gas technologies in the construction of new and reconstruction of existing power plants;
• development and production of highly efficient steam turbine units new generations at super-supercritical steam parameters and at temperatures of 600°C and higher with increasing efficiency. up to 55% or more;
• production of energy boilers with improved organization of combustion processes, the use of new burners and other devices that reduce harmful emissions into the atmosphere;
• creation and development of boiler units with circulating fluidized bed furnaces for power units with a capacity of 200–300 MW;
• creation of equipment for environmentally friendly combined cycle gas plants with fluidized bed boilers under pressure;
• development and mastery of advanced solid fuel combustion technologies;
• creation of gasification systems for solid fuels in order to develop environmentally friendly combined cycle gas plants using coal and for technical re-equipment pulverized coal power plants.