Environmental problems associated with the use of fuel. Ecological problem of using heat engines

The impact of thermal power plants on the environment largely depends on the type of fuel burned (solid and liquid).

When burning solid fuel fly ash with particles of unburned fuel, sulfurous and sulfuric anhydrides, nitrogen oxides, a certain amount of fluorine compounds, as well as gaseous products of incomplete combustion of fuel enter the atmosphere. Fly ash in some cases contains, in addition to non-toxic components, more harmful impurities. So, in the ash of Donetsk anthracites, arsenic is contained in small amounts, and in the ash of Ekibastuz and some other deposits - free silicon dioxide, in the ash of shales and coals of the Kansk-Achinsk basin - free calcium oxide.

Coal - the most abundant fossil fuel on our planet. Experts believe that its reserves will last for 500 years. In addition, coal is more evenly distributed throughout the world and is more economical than oil. Synthetic liquid fuel can be obtained from coal. The method of obtaining fuel by processing coal has long been known. However, the cost of such products was too high. The process takes place at high pressure. This fuel has one indisputable advantage - it has a higher octane rating. This means that it will be more environmentally friendly.

Peat. The energy use of peat has a number of negative consequences for environment arising from large-scale peat mining. These include, in particular, violation of the regime of water systems, changes in the landscape and soil cover in peat extraction sites, deterioration in the quality of local fresh water sources and pollution of the air basin, and a sharp deterioration in the living conditions of animals. Significant environmental difficulties also arise in connection with the need to transport and store peat.

When burning liquid fuel(fuel oil) with flue gases into the atmospheric air enter: sulfurous and sulfuric anhydrides, nitrogen oxides, vanadium compounds, sodium salts, as well as substances removed from the surface of boilers during cleaning. From an environmental standpoint, liquid fuels are more “hygienic”. At the same time, the problem of ash dumps, which occupy large areas, completely disappears, excludes them. beneficial use and are a source of constant atmospheric pollution in the station area due to the removal of part of the ash with the winds. There is no fly ash in the combustion products of liquid fuels.

Natural gas. When burning natural gas Nitrogen oxides are a significant air pollutant. However, the emission of nitrogen oxides when natural gas is burned at thermal power plants is on average 20% lower than when coal is burned. This is due not to the properties of the fuel itself, but to the peculiarities of the combustion processes. The excess air ratio for coal combustion is lower than for natural gas combustion. Thus, natural gas is the most environmentally friendly type of energy fuel in terms of the release of nitrogen oxides during combustion.

The complex impact of thermal power plants on the biosphere as a whole is illustrated in Table. one.

Thus, coal, oil and oil products, natural gas and, less commonly, wood and peat are used as fuel in thermal power plants. The main components of combustible materials are carbon, hydrogen and oxygen, sulfur and nitrogen are contained in smaller amounts, traces of metals and their compounds (most often oxides and sulfides) are also present.

In the thermal power industry, the source of massive atmospheric emissions and large-tonnage solid waste are thermal power plants, enterprises and installations of steam power facilities, i.e. any enterprises whose work is associated with fuel combustion.

Along with gaseous emissions, thermal power engineering produces huge masses of solid waste. These include ash and slag.

Waste coal preparation plants contain 55-60% SiO 2 , 22-26% Al 2 O 3 , 5-12% Fe 2 O 3 , 0.5-1% CaO, 4-4.5% K 2 O and Na 2 O and up to 5% C. They enter the dumps, which produce dust, smoke and drastically worsen the state of the atmosphere and adjacent territories.

Life on Earth arose in a reducing atmosphere, and only much later, after about 2 billion years, did the biosphere gradually transform the reducing atmosphere into an oxidizing one. Wherein living matter previously taken out of the atmosphere various substances, in particular, carbon dioxide, forming huge deposits of limestone and other carbonaceous compounds. Now our technogenic civilization has generated a powerful flow of reducing gases, primarily due to the burning of fossil fuels in order to obtain energy. For 30 years, from 1970 to 2000, about 450 billion barrels of oil, 90 billion tons of coal, 11 trillion. m 3 of gas (Table 2).

Air emissions from a 1,000 MW/year power plant (tonnes)

The main part of the emission is occupied by carbon dioxide - about 1 million tons in terms of carbon 1 Mt. With wastewater from a thermal power plant, 66 tons of organic matter, 82 tons of sulfuric acid, 26 tons of chlorides, 41 tons of phosphates and almost 500 tons of suspended particles are annually removed. Ash from power plants often contains elevated concentrations of heavy, rare earth and radioactive substances.

A coal-fired power plant requires 3.6 million tons of coal, 150 m 3 of water and about 30 billion m 3 of air annually. These figures do not take into account environmental disturbances associated with the extraction and transportation of coal.

Considering that such a power plant has been actively operating for several decades, then its impact can be compared with that of a volcano. But if the latter usually throws out the products of volcanism in large quantities at a time, then the power plant does this all the time. For tens of millennia, volcanic activity has not been able to noticeably affect the composition of the atmosphere, and human economic activity has caused such changes over some 100-200 years, mainly due to the combustion of fossil fuels and emissions greenhouse gases destroyed and deformed ecosystems.

Coefficient useful action power plants is still small and amounts to 30-40%, most of fuel is wasted. The received energy is used in one way or another and eventually turns into heat, i.e., in addition to chemical pollution, thermal pollution enters the biosphere.

Pollution and waste from energy facilities in the form of gas, liquid and solid phases are distributed into two streams: one causes global changes, and the other causes regional and local ones. The same is true in other sectors of the economy, but still energy and fossil fuel combustion remain a source of major global pollutants. They enter the atmosphere, and due to their accumulation, the concentration of small gas components of the atmosphere, including greenhouse gases, changes. In the atmosphere, gases appeared that were practically absent in it before - chlorofluorocarbons. These are global pollutants that have a high greenhouse effect and at the same time participate in the destruction of the stratospheric ozone screen.

Thus, it should be noted that on present stage thermal power plants emit into the atmosphere about 20% of the total amount of all harmful industrial waste. They significantly affect the environment of the area of their location and the state of the biosphere as a whole. The most harmful are condensing power plants operating on low-grade fuels. So, when burning at the station for 1 hour 1060 tons of Donetsk coal, 34.5 tons of slag is removed from the furnaces of boilers, 193.5 tons of ash is removed from the bunkers of electrostatic precipitators that clean gases by 99%, and 10 million m 3 are emitted into the atmosphere through pipes flue gases. These gases, in addition to nitrogen and oxygen residues, contain 2350 tons of carbon dioxide, 251 tons of water vapor, 34 tons of sulfur dioxide, 9.34 tons of nitrogen oxides (in terms of dioxide) and 2 tons of fly ash not “caught” by electrostatic precipitators.

Wastewater Thermal power plants and storm drains from their territories, contaminated with waste from technological cycles of power plants and containing vanadium, nickel, fluorine, phenols and oil products, when discharged into water bodies, can affect water quality and aquatic organisms. Change chemical composition of certain substances leads to a violation of the habitat conditions established in the reservoir and affects the species composition and abundance aquatic organisms and bacteria, and ultimately can lead to violations of the processes of self-purification of water bodies from pollution and to the deterioration of their sanitary condition.

The so-called thermal pollution of water bodies with diverse violations of their condition is also dangerous. Thermal power plants produce energy using turbines driven by heated steam. During the operation of the turbines, it is necessary to cool the exhaust steam with water, therefore, a stream of water continuously departs from the power plant, usually heated by 8-12 ° C and discharged into the reservoir. Large thermal power plants need large volumes of water. They discharge 80-90 m 3 /s of water in a heated state. This means that a powerful stream continuously enters the reservoir. warm water about the same scale as the Moscow River.

The heating zone, formed at the confluence of a warm "river", is a kind of section of the reservoir, in which the temperature is maximum at the spillway point and decreases with distance from it. The heating zones of large thermal power plants occupy an area of several tens of square kilometers. In winter, polynyas form in the heated zone (in the northern and middle latitudes). During the summer months, the temperatures in the heated zones depend on the natural temperature of the intake water. If the water temperature in the reservoir is 20 °C, then in the heating zone it can reach 28-32 °C.

As a result of an increase in temperatures in a reservoir and a violation of their natural hydrothermal regime, the processes of “blooming” of water are intensified, the ability of gases to dissolve in water decreases, the physical properties of water change, all chemical and biological processes occurring in it are accelerated, etc. In the heating zone the transparency of water decreases, pH increases, the rate of decomposition of easily oxidized substances increases. The rate of photosynthesis in such water is markedly reduced.

Among other social dangers, one of the first places is occupied by those associated with the use of heat engines.

What are heat engines for us

Every day we deal with the engines that drive cars, ships, industrial machinery, railway locomotives and aircraft. It was the emergence and widespread use of heat engines that rapidly advanced the industry.

Ecological problem The use of heat engines lies in the fact that thermal energy emissions inevitably lead to heating of surrounding objects, including the atmosphere. Scientists have long been struggling with the problem of the rise in the level of the World Ocean, considering the main factor influencing human activity. Changes in nature will lead to a change in the conditions of our life, but despite this, energy consumption is increasing every year.

Where are heat engines used?

Millions of cars with engines internal combustion engaged in the transport of passengers and goods. Powerful diesel locomotives go along the railways, motor ships go along the water trajectories. Airplanes and helicopters are equipped with piston, turbojet and turboprop engines. Rocket engines "push" in space stations, ships and satellites of the Earth. Internal combustion engines in agriculture are installed on combines, pumping stations, tractors and other objects.

Ecological problem of using heat engines

Human-used machines, heat engines, automobile manufacturing, gas turbine propulsion applications, aviation and rocket launchers, pollution aquatic environment ships - all this has a catastrophically destructive effect on the environment.

First, when coal and oil are burned, nitrogen and sulfur compounds detrimental to humans. Secondly, the processes use atmospheric oxygen, the content of which in the air drops because of this.

Air emissions are not the only factor in the impact of heat engines on nature. Production of mechanical and electrical energy cannot be carried out without significant amounts of heat being removed to the environment, which cannot but lead to an increase in the average temperature on the planet.

It is aggravated by the fact that the burning substances increase the concentration of carbon dioxide in the atmosphere. This, in turn, leads to the emergence of the "greenhouse effect". Global warming is becoming a real danger.

The environmental problem of using heat engines is that the combustion of fuel cannot be complete, and this leads to the release of ash and soot flakes into the air we breathe. According to statistics, worldwide power plants annually release into the air more than 200 million tons of ash and more than 60 million tons of sulfur oxide.

All civilized countries are trying to solve the environmental problems associated with the use of heat engines. The latest energy-saving technologies are being introduced to improve thermal engines. As a result, energy consumption for the production of the same product is significantly reduced, reducing the harmful effect on the environment.

Thermal power plants, internal combustion engines of automobiles and other machines are discharged in large quantities into the atmosphere, and then into the soil, harmful to all living wastes, for example, chlorine, sulfur compounds (during the combustion of coal), carbon monoxide CO, nitrogen oxides, etc. Car engines release about three tons of lead into the atmosphere every year.

At nuclear power plants, another environmental problem in the use of thermal engines is the safety and disposal of radioactive waste.

Due to the incredibly high energy consumption, some regions have lost the ability to self-clean their own airspace. The operation of nuclear power plants has helped to significantly reduce harmful emissions, but operation requires huge amounts of water and large space under the ponds to cool the exhaust steam.

Solutions

Unfortunately, humanity is unable to abandon the use of heat engines. Where is the exit? In order to consume an order of magnitude less fuel, that is, to reduce energy consumption, it is necessary to increase the efficiency of the engine to carry out the same work. Fighting negative consequences The use of heat engines is only to increase the efficiency of energy use and switch to energy-saving technologies.

In general, it would be wrong to say that the global environmental problem of using heat engines is not being solved. An increasing number of electric locomotives are replacing conventional trains; battery cars are becoming popular; energy-saving technologies are introduced into the industry. There is hope that environmentally friendly aircraft and rocket engines will appear. Many governments are implementing international programs for the protection of the environment, directed against pollution of the Earth.

A heat engine is a device capable of converting the amount of heat received into mechanical work. Mechanical work in heat engines is performed in the process of expansion of a certain substance, which is called the working fluid. As a working fluid, gaseous substances (gasoline vapors, air, water vapor) are usually used. working body receives (or gives) thermal energy in the process of heat exchange with bodies having a large supply of internal energy.

ENVIRONMENTAL CRISIS, disruption of relationships within an ecosystem or irreversible phenomena in the biosphere caused by anthropogenic activities and threatening the existence of man as a species. According to the degree of threat natural life human and the development of society stand out unfavorable ecological situation, ecological disaster and ecological catastrophe

Pollution from heat engines:

1. Chemical.

2. Radioactive.

3. Thermal.

Efficiency of heat engines< 40%, в следствии чего больше 60% теплоты двигатель отдаёт холодильнику.

When fuel is burned, oxygen from the atmosphere is used, as a result of which the oxygen content in the air gradually decreases.

Fuel combustion is accompanied by the release of carbon dioxide, nitrogen, sulfur and other compounds into the atmosphere.

Pollution Prevention Measures:

1.Reduction of harmful emissions.

2.Exhaust gas control, filter modification.

3. Comparison of the efficiency and environmental friendliness of various types of fuel, the transfer of transport to gas fuel.

The main toxic vehicle emissions include: exhaust gases, crankcase gases and fuel fumes. The exhaust gases emitted by the engine contain carbon monoxide, hydrocarbons, nitrogen oxides, benzapyrene, aldehydes and soot. On average, with a car running 15 thousand km a year, it burns more than 2 tons of fuel and consumes about 30 tons of air. At the same time, about 700 kg are emitted into the atmosphere. carbon monoxide(CO), 400 kg of nitrogen dioxide, 230 kg of hydrocarbons and other pollutants, total which is more than 200 items. Every year, about 1 million tons of pollutants are emitted into the atmospheric air with exhaust gases from mobile sources.

Some of these substances, such as heavy metals and certain organochlorine compounds, persistent organic pollutants accumulate in natural environment and pose a serious threat to both the environment and human health. While maintaining the current growth rate of the car park, it is predicted that by 2015 the volume of pollutant emissions into the atmospheric air will increase to 10% or more.

An electric car could radically solve the problem of air pollution by transport. Today, electric locomotives are most widely used in railway transport.

2. From an environmental point of view, hydrogen is the best fuel for cars, which, in addition, is the most calorific

3. Attempts are being made to create engines using air, alcohol, biofuel, etc. as fuel. But, unfortunately, so far all these engines can rather be called experimental samples. But science does not stand still, let's hope that the process of creating an environmentally friendly car is not far off
Causes of air pollution from exhaust gases
cars.

The main cause of air pollution is the incomplete and uneven combustion of fuel. Only 15% of it is spent on the movement of the car, and 85% "flies into the wind." In addition, the combustion chambers of an automobile engine are a kind of chemical reactor that synthesizes toxic substances and throwing them into the atmosphere. Even innocent nitrogen from the atmosphere, getting into the combustion chamber, turns into toxic nitrogen oxides.
The exhaust gases of an internal combustion engine (ICE) contain over 170 harmful components, of which about 160 are derivatives of hydrocarbons, which are directly due to the incomplete combustion of fuel in the engine. Presence in exhaust gases harmful substances ultimately determined by the type and conditions of fuel combustion.
Exhaust gases, wear products of mechanical parts and vehicle tires, as well as road surfaces, account for about half of atmospheric emissions of anthropogenic origin. The most studied are emissions from the engine and crankcase of a car. The composition of these emissions, in addition to nitrogen, oxygen, carbon dioxide and water, includes such harmful components as oxide. Moving at a speed of 80-90 km / h on average, a car converts as much oxygen into carbon dioxide as 300-350 people. But it's not just carbon dioxide. The annual exhaust of one car is 800 kg of carbon monoxide, 40 kg of nitrogen oxides and more than 200 kg of various hydrocarbons. In this set, carbon monoxide is very insidious. Due to its high toxicity, its permissible concentration in the atmospheric air should not exceed 1 mg/m3. There are cases of tragic deaths of people who started car engines with the garage doors closed. In a single-seat garage, a lethal concentration of carbon monoxide occurs within 2-3 minutes after the starter is turned on. In the cold season, stopping for the night on the side of the road, inexperienced drivers sometimes turn on the engine to heat the car. Due to the penetration of carbon monoxide into the cabin, such an overnight stay may be the last.
Nitrogen oxides are toxic to humans and, in addition, have an irritating effect. A particularly dangerous component of exhaust gases are carcinogenic hydrocarbons, found primarily at intersections at traffic lights (up to 6.4 µg/100 m3, which is 3 times more than in the middle of the quarter).
When using leaded gasoline, the car engine releases lead compounds. Lead is dangerous because it can accumulate both in the external environment and in the human body.
The level of gas contamination of highways and at main territories depends on the intensity of car traffic, the width and topography of the street, wind speed, the proportion freight transport and buses in the general flow and other factors. With a traffic intensity of 500 vehicles per hour, the concentration of carbon monoxide in an open area at a distance of 30-40 m from the highway decreases by 3 times and reaches the norm. Difficulty dispersing car emissions in tight streets. As a result, almost all residents of the city experience bad influence polluted air.
Of the metal compounds that make up the solid emissions of vehicles, the most studied are lead compounds. This is due to the fact that lead compounds, entering the human body and warm-blooded animals with water, air and food, have the most harmful effect on it. Up to 50% of the daily intake of lead in the body falls on the air, in which a significant proportion is the exhaust gases of cars.
The release of hydrocarbons into the atmospheric air occurs not only during the operation of cars, but also during the spill of gasoline. According to American researchers in Los Angeles, about 350 tons of gasoline evaporate into the air per day. And it is not so much the car that is to blame for this, but the person himself. They spilled a little when pouring gasoline into a tank, forgot to close the lid tightly during transportation, splashed it on the ground when refueling at a gas station, and various hydrocarbons were drawn into the air.
Every motorist knows: it is almost impossible to pour all the gasoline into the tank from the hose, some part of it from the “pistol” barrel necessarily splashes onto the ground. A little. But how many cars do we have today? And every year their number will grow, which means that harmful fumes into the atmosphere will also increase. Only 300 g of gasoline spilled while refueling a car pollutes 200,000 cubic meters air. The easiest way to solve the problem is to create filling machines new design, not allowing even one drop of gasoline to spill onto the ground.

Conclusion

It can be said without exaggeration that heat engines are currently the main converters of fuels into other types of energy, and without them progress in development would be impossible modern civilization. However, all types of heat engines are sources of environmental pollution. (Kostryukov Denis)

Analysis of the problem of extending the mechanisms of the Kyoto Protocol after the end of the first commitment period

graduate work

2.3 Determination of categories of emission sources associated with fuel combustion for energy needs

The revised 1996 IPCC Guidelines introduce the following classification of major source categories:

1) Energy. This category includes thermal power plants and CHPPs of RAO UES, and regional AO Energos, industrial CHPPs, other power plants, municipal and industrial boiler houses that supply energy to the grid common use for the needs of electricity and heat supply in the region, as well as enterprises of the fuel industry. The consumption of fuel for the generation of electricity and heat and for own needs, as well as losses are taken into account;

2) Industry and construction. In total, this category includes enterprises of all industries operating in the region, including ferrous metallurgy, non-ferrous metallurgy, chemical and petrochemical industries, light industry, food, forestry (logging) and woodworking and pulp and paper, machine building, production of building materials and construction itself, etc. The consumption of fuel burned for all final (own) energy needs in all basic ( production) and auxiliary shops and facilities of enterprises (organizations);

3) Transport. Includes rail, air, water, road and pipeline. The consumption of fuel burned directly by vehicles is taken into account, excluding on-farm transportation and auxiliary needs of transport enterprises;

4) The domestic sector includes social sphere services, urban economy, trade, catering and services. The consumption of fuel directly burned by enterprises for final energy needs is taken into account;

5) Population. The consumption of fuel burned in the household for various energy needs is taken into account;

6) Agriculture. The consumption of fuel burned by stationary and mobile sources during various agricultural activities by organizations of any type is taken into account. This is due to the composition of information on fuel and energy consumption in agriculture, adopted in Russian statistics;

7) Other stationary and mobile sources. The consumption of fuel burned for all other needs is taken into account, for which there is statistical information on fuel consumption, but it is not clear to which category it should be assigned.

The UNFCCC also has a number of features in the issue of ownership of GHG emissions, which should be specially noted.

Emissions from electricity production are wholly owned by the person who generated (and sold) it. That is, saving electricity is a reduction in greenhouse gas emissions only if the power plant is also included in the project or program to reduce emissions and the reduction is actually observed at the plant.

Emissions associated with bunker fuel sold to ships and aircraft that are international vehicles are reported separately and are not included in national emissions. That is, for the time being, they are actually excluded from the emission control system due to the impossibility of reaching a consensus on the issue of emission ownership (fuel shipment port, ship flag, ship registration place, etc.).

Emissions associated with the disposal and processing of waste do not belong to enterprises that produce waste, but to organizations involved in the operation of landfills and treatment facilities.

As a rule, greenhouse gas emissions are estimated there according to the gross data on the processing of solid or liquid waste.

Emissions from the combustion or decomposition of wood and its products, as well as agricultural waste (straw, etc.), are assumed where the wood was harvested and in the year of harvest. There is a very important consequence of this: the use of products or waste wood as fuel is not an emission. It is assumed that the removal of wood from the forest is already included as an emission in the calculation. overall balance CO 2 in forests (absorption minus emission).

There are direct and indirect greenhouse gas emissions.

Direct greenhouse gas emissions are emissions from sources that are owned or controlled by the enterprise conducting the inventory, such as emissions from boilers, manufacturing and ventilation installations through factory chimneys, emissions from vehicles owned by the enterprise.

Indirect greenhouse gas emissions - emissions that occur as a result of activities this enterprise, but outside its control, for example: emissions from the production of electricity that the enterprise buys; emissions from the production of products purchased under contracts; emissions associated with the use of manufactured products. According to the methodology of the IPCC, the inventory implies taking into account only direct emissions. Company-level inventory methodologies, such as those developed by the World Business Council for sustainable development The GHG Accounting Protocol recommends taking into account indirect emissions in certain cases. Also, when planning projects to reduce emissions, it is desirable to at least approximately estimate indirect emissions, since their changes as a result of the project can significantly increase or decrease the value of the project.

The absorption of CO 2 by forests and agricultural lands is a "minus emission".

Under the UNFCCC and the Kyoto Protocol, absorption (also called greenhouse gas sinks or removals) is also accounted for, but separately from emissions. In some cases, it is considered to be equivalent to emissions, for example when calculating country-level commitments for the first commitment period of the Kyoto Protocol. But in most cases, CO2 uptake by forests is highly unequal, which to some extent reflects the temporality and instability of such absorption, because forests cannot store carbon forever, in the end the wood either decomposes or is burned - and CO 2 is returned back in atmosphere. For this, special absorption units have been introduced, there are strong restrictions on the types of forest projects, etc.

In methodological terms, the issues of accounting for absorption have not yet been finally resolved on international level. For example, the IPCC methodology does not include a chapter on absorption due to land use change at all. Due to the great difficulties, it was decided to prepare a separate Toolkit which is nearing completion.

Since this publication is of a general educational nature, without an emphasis on forestry activities, a huge array of problems and difficulties in accounting for CO 2 absorption by forests is not considered in detail here.

Known inventory techniques allow you to approach it very flexibly. They practically imply several "levels" of detail and precision in the estimation of outliers. The simplest level (level 1) usually requires a minimum of data and analytical capabilities. The more complex (Tier 2) is based on detailed data and usually takes into account specific features country/region. Most high level(Tier 3) implies disaggregation of data to the level of enterprises and individual installations and direct measurements of emissions of most gases.

The obligatory use of one or another level is usually not regulated by international methodology, but depends on decisions at the national level. These issues are discussed in detail below, in the methodological section.

In the vast majority of cases, emissions from a source are not measured, but calculated from data on fuel consumption and production (if its production leads to greenhouse gas emissions), etc. In the very general view calculation is based on the scheme:

(data on some activity, such as fuel combustion) x (emission factors) = (emissions)

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Federal State Budgetary Educational Institution of Higher Professional Education

"Saratov State Technical University named after Yu.A. Gagarin»

Vocational Pedagogical College.

Abstract on the topic: "Ecological problems associated with the use of heat engines"

Work completed

student of group ZChS-912

Petrova Olesya

Introduction

5. Environmental protection from thermal emissions

Conclusion

release thermal atmosphere fuel

Introduction

There is an inextricable relationship and interdependence of the conditions for ensuring heat and power consumption and environmental pollution. The interaction of these two factors of human life and the development of production forces attracts gradual attention to the problem of interaction between heat power engineering and the environment.

At an early stage in the development of thermal power engineering, the main manifestation of this attention was the search in the environment for resources necessary to ensure heat and power consumption and stable heat and power supply to enterprises and residential buildings. In the future, the boundaries of the problem covered the possibility of a more complete use of natural resources by finding and rationalizing processes and technologies, extracting and enriching, processing and burning fuel, as well as improving thermal power plants.

With the growth of unit capacities of units, thermal power stations and thermal power systems, specific and total levels of heat and power consumption, the task arose of limiting polluting emissions into the air basin, as well as more fully using their natural dissipative capacity.

At the present stage, the problem of interaction between thermal power engineering and the environment has acquired new features, spreading its influence over the vast volumes of the Earth's atmosphere.

Even more significant scales of development of heat and power consumption in the foreseeable future predetermine further intensive growth of various impacts on the atmosphere.

Fundamentally new aspects of the problem of interaction between thermal power engineering and the environment have arisen in connection with the development of nuclear thermal power engineering.

The most important side of the problem of interaction between thermal power engineering and the environment in the new conditions is the ever-increasing reverse influence, the determining role of environmental conditions in solving practical tasks thermal power engineering (selection of the type of thermal power plants, location of enterprises, selection of unit capacities of power equipment and much more).

1. general characteristics thermal power industry and its emissions

Thermal power engineering is one of the main components of the energy industry and includes the process of generating thermal energy, transportation, considers the main conditions for energy production and the side effects of the industry on the environment, the human body and animals.

As Yu.V. Novikov, in terms of total emissions of harmful substances into the atmosphere, thermal power engineering ranks first among industries.

If a steam boiler is the “heart” of a power plant, then water and steam are its “blood”. They circulate inside the plants, turning the turbine blades. So this "blood" was made supercritical by increasing its temperature and pressure several times. Thanks to this, the efficiency of power plants has increased significantly. Such extreme conditions ordinary metals could not survive. It was necessary to create fundamentally new, so-called structural materials for supercritical temperatures.

The lion's share of electricity is generated in the world at thermal and nuclear power plants, where water vapor serves as the working fluid. The transition to its supercritical parameters (temperature and pressure) made it possible to increase the efficiency from 25 to 40%, which gave a huge savings in primary energy resources - oil, coal, gas - and in a short time greatly increased the power supply of our country. This became real largely due to the fundamental research of A.E. Sheindlin thermophysical properties of water vapor in supercritical states. In parallel with it, many scientists of the world were developing in this direction, but the domestic energy industry managed to find a solution. He developed methods and experimental setups that had no analogues in the world. The results of calculations by A.E. Sheindlin became the basis for the construction of power plants in many countries. In 1961, Sheindlin created the Institute for High Temperatures, which became one of the leading scientific centers of the Russian Academy of Sciences.

International Award Committee " global energy determined three laureates. The 2004 bonus fund of $900,000 was divided between them. The prize "For the development of physical and technical foundations and the creation of fast neutron power reactors" was awarded to Academician of the Russian Academy of Sciences Fedor Nitenkov and Professor Leonard J. Koch (USA). Academician of the Russian Academy of Sciences Alexander Sheindlin was awarded the prize "For fundamental research of the thermophysical properties of substances at extremely high temperatures for power engineering".

2. Impact on the atmosphere when using solid fuel

Coal industry enterprises have a significant negative impact on water and land resources. The main sources of emissions of harmful substances into the atmosphere are industrial, ventilation and aspiration systems of mines and processing plants, etc.

Pollution of the air basin in the process of open and underground coal mining, transportation and enrichment of hard coal is caused by drilling and blasting, the operation of internal combustion engines and boiler houses, dusting of coal warehouses and rock dumps, and other sources.

In 2002, the volume of emissions of harmful substances into the atmosphere from the enterprises of the industry increased by 30% compared to 1995, mainly due to newly taken into account methane emissions from ventilation and degassing installations at mines.

In terms of emissions of harmful substances, the coal industry ranks sixth in the industry Russian Federation(contribution at the level of 5%). The degree of capture and neutralization of pollutants is extremely low (9.1%), while hydrocarbons and VOCs are not captured.

In 2002, emissions of hydrocarbons (by 45.5 thousand tons), methane (by 40.6 thousand tons), soot (by 1.7 thousand tons), and a number of other substances increased; there was a decrease in emissions of VOCs (by 5.2 thousand tons), sulfur dioxide (by 2.8 thousand tons), solid substances (by 2.2 thousand tons).

The zoning of coal supplied from individual suppliers to thermal power plants exceeds 79% (in the UK it is 22% in accordance with the law, in the USA it is 9%). And the increase in fly ash emissions into the atmosphere continues. Meanwhile, only one Semibratov plant produces electrostatic precipitators for ash collection, satisfying the annual demand for them by no more than 5%.

Solid fuel thermal power plants intensively emit into the atmosphere products of coal and shale, containing up to 50% of non-combustible mass and harmful impurities. The share of thermal power plants in the country's electricity balance is 79%. They consume up to 25% of the produced solid fuel and discharge more than 15 million tons of ash, slag and gaseous substances into the human environment.

In the US, coal continues to be the main fuel for power plants. By the end of the century, all power plants there must become environmentally friendly, and efficiency must be increased to 50% or more (now 35%). To accelerate the adoption of coal cleaning technologies, a number of coal, energy and engineering companies, with federal government support, have developed a program that will require $3.2 billion to implement. Within 20 years, in the USA alone, new technologies will be introduced at existing power plants with a total capacity of 140,000 MW and at new converted power plants with a total capacity of 170,000 kW.

Environmentaltechnologyincinerationfuel. The traditional diffusion method of burning even high-quality hydrocarbon fuels leads to pollution ambient atmosphere mainly nitrogen oxides and carcinogens. In this regard, environmentally friendly technologies for burning these types of fuel are needed: high quality spraying and mixing with air to the combustion zone and intensive combustion of a depleted, pre-mixed, fuel-air mixture, an optimal combustion chamber (CC) from a thermochemical point of view should provide preliminary evaporation of the fuel, complete and uniform mixing of its vapors with air and stable combustion of depleted fuel mixture with a minimum time of its stay in the combustion zone.

In this regard, the traditional diffuse hybrid combustion method is much more efficient, which is a combination of a diffuse zone with a channel for pre-evaporation and mixing of fuel with air.

Technologies have been developed for burning coal in boilers with a circulating fluidized bed, where the effect of binding environmentally hazardous sulfur impurities is achieved. This technology was introduced during the reconstruction of Shaturskaya, Cherepetskaya and Intinskaya GRES. A thermal power plant with modern boilers is being built in Ulan-Ude. The Teploelektroproekt Institute has developed a technology for coal gasification: it is not the coal itself that is burned, but the gas released from it. This is an environmentally friendly process, but so far it, like any new technology, dear. In the future, even petroleum coke gasification technologies will be introduced.

When coal is burned in a fluidized bed, the emission of sulfur compounds into the atmosphere is reduced by 95%, and nitrogen oxides - by 70%.

Flue gas cleaning. To clean flue gases, a lime-catalytic two-stage method is used to obtain gypsum, based on the absorption of sulfur dioxide by a limestone suspension in two stages of contact. This technology, as evidenced by world experience, is most common at thermal power plants that burn liquid and solid fuels with different sulfur content in it, and provides a degree of gas purification from sulfur oxides of at least 90-95%. A large number of domestic power plants operate on fuel with medium and high content sulfur in it, so this method should be widely used in the domestic energy sector. In our country, there was practically no experience in cleaning flue gases from sulfur dioxide by the wet limestone method.

Thermal power plants account for about 70% of nitrogen oxide emissions into the atmosphere. In the USA and Japan, methods for cleaning flue gases from nitrogen oxides are widely used, in these countries there are more than 100 installations that use the method of selective catalytic reduction of nitrogen oxides with ammonia on a platinum-vanadium catalyst, however, the cost of these installations is very high, and the service life catalyst is negligible.

AT last years In the United States, Genesis Research of Arizona has developed a technology for producing the so-called self-cleaning coal. Such coal burns better, and when it is used, 80% less sulfur dioxide is found in flue gases, while additional costs are only a fraction of the costs of installing scrubbers. The technology for producing self-cleaning coal includes two stages. Initially, impurities are separated from the coal by flotation, then the coal is ground into powder and added to the sludge, while the coal floats and the impurities sink. At the first stage, almost all inorganic sulfur is removed, while organic sulfur remains. In the second stage, the powdered charcoal is combined with chemicals whose names are trade secrets and then compacted into grape-sized lumps. When burned, these chemicals react with organic sulfur, and the sulfur is securely sealed to prevent it from escaping into the atmosphere. Lumps of such modified coal can be transported, stored and used like regular coal.

Steam and gas systems. An effective integrated system that not only captures harmful impurities from the flue gases of thermal power plants, but also reduces the specific fuel consumption for electricity generation by about 20%, was developed in Energy Institute G.N. Krzhizhanovsky. Its essence is that before burning in the furnace of TPP steam boilers, coal is gasified, cleaned of solid (containing harmful substances) impurities and sent to gas turbines, where combustion products with a temperature of 400-500 degrees Celsius are discharged into ordinary steam boilers. Similar combined-cycle systems are widely used by power engineers in a number of countries to reduce emissions into the atmosphere.

Deep complex processing of coal. Abroad, intensive work is underway to develop technologies and equipment for coal gasification to fully supply the industry with combustible gases, synthesis gas and hydrogen. A demonstration coal oxy-gasification plant for a 250 MW power unit has been commissioned in the Netherlands. It is planned to commission four such units from 175 to 330 MW in Europe, ten units from 100 to 500 MW in the USA and one unit with a capacity of 400 MW in Japan. Gasification processes at high temperatures and pressures make it possible to process a wide range of coals. There are known studies on high-speed pyrolysis and catalytic gasification, the implementation of which promises huge benefits.

The need to deepen the processing of coal is dictated by the previous course of development of the heat and power industry: the best results are achieved with the combined processing of coal into electricity and heat. A qualitative leap in the use of coal is associated with its complex processing within the framework of flexible technologies. Solution to this difficult problem will require new technological installations for energy-chemical complexes, which will ensure an increase in the efficiency of thermal power plants, a reduction in capital unit costs and a fundamental solution to environmental issues.

3. Impact on the atmosphere when using liquid fuel

At one time, oil supplanted coal and came out on top in the global energy balance. However, this is fraught with certain environmental problems.

Yes, in 2002 Russian enterprises industries emitted 621 thousand tons of pollutants into the atmosphere ( solids, sulfur dioxide, carbon monoxide, nitrogen oxides, etc.). Wastewater in the amount of up to 1302.6 million m3 is discharged into surface water bodies and on relief.

When liquid fuels (fuel oil) are burned with flue gases, sulfur dioxide and sulfuric anhydrides, nitrogen oxides, gaseous and solid foods incomplete combustion of fuel, vanadium compounds, sodium salts, as well as substances removed from the surface of boilers during cleaning. From an ecological point of view, liquid fuel has more “hygienic” properties: there is no problem of ash dumps, which occupy large areas, exclude their beneficial use and are a source of constant pollution of the atmosphere and the station area due to ash carried away with winds. There is no fly ash in the combustion products of liquid fuels. The use of dual-fuel hybrid combustion chambers instead of traditional single-zone diffusion combustion chambers using partial replacement of a part of hydrocarbon fuel with hydrogen (6% of the mass of hydrocarbon fuel) reduces the consumption of petroleum fuel by 17-20%, the emission levels of soot particles - by an order of magnitude, benzopyrene - by 10-15 times, nitrogen oxides - 5 times).

In most countries, the combustion of petroleum fuels with a sulfur content above 0.5% is prohibited, while in Russia half of the diesel fuel does not fit into this standard, and the sulfur content of boiler fuel reaches 3%.

Burn oil, in the words of D.I. Mendeleev, it's the same as heating the stove with banknotes. Therefore, the share of the use of liquid fuel in the energy sector has been significantly reduced in recent years. The emerging trend will further intensify due to a significant expansion of the use of liquid fuels in other areas of the national economy: in transport, in the chemical industry, including the production of plastics, lubricants, household chemicals, etc. Unfortunately, oil is not used in the best way. In 1984, with the world production of petroleum products of 2750 million tons of gasoline, 600 million tons of kerosene and jet fuel - 210, diesel fuel - 600, fuel oil - 600 million tons were obtained. Good example Resource conservation has shown Japan, which seeks to minimize the country's dependence on oil imports. To address this important economic task over the past 20 years, simply gigantic efforts have been made. Priority attention was given to energy-saving technology. And as a result of the work done, for the production of the same volume of the gross national product of Japan today, half as much oil is required as in 1974. Undoubtedly, innovations have had a positive impact on improving the environmental situation.

4. Impact on the atmosphere when using natural gas

According to environmental criteria, natural gas is the most optimal fuel. The combustion products do not contain ash, soot and carcinogens such as benzopyrene.

When gas is burned, nitrogen oxides remain the only significant air pollutant. However, the emission of nitrogen oxides when natural gas is burned at thermal power plants is on average 20 percent lower than when coal is burned. This is due not to the properties of the fuel itself, but to the peculiarities of the processes of their combustion. The excess air ratio for coal combustion is lower than for natural gas combustion. Thus, natural gas is the most environmentally friendly type of energy fuel in terms of the release of nitrogen oxides during combustion.

Changes in the environment during gas transportation. A modern main pipeline is a complex engineering equipment, which, in addition to the linear part (the pipeline itself), includes installations for preparing oil or gas for pumping, pumping and compressor stations, tank farms, communication lines, an electrochemical protection system, roads running along the route, and entrances to them, as well as temporary residential settlements of operators.

For example, total length gas pipelines in Russia is approximately 140 thousand km. For example, on the territory of the Udmurt Republic there are 13 main pipelines, the share of emissions of which is more than 30% of the corresponding volume in the republic. Emissions, mainly of methane, are distributed along the length of gas pipelines, mostly outside of populated areas.

Atmospheric air is exposed to significant pollution due to losses from large and small “breaths” of reservoirs, gas leaks, etc.

Atmospheric pollution as a result of an accidental release of gas or the combustion of oil and oil products, which are different on the surface during an accident, is characterized by a much shorter period of exposure, and it can be classified as short-term.

Atmospheric air is also polluted as a result of gas leakage through leaky pipeline connections, leakage and evaporation during storage and loading and unloading operations, losses in oil and gas and oil product pipelines, etc. As a result, vegetation growth can be suppressed and airborne exposure limits can be raised.

5. Protection of the atmosphere from thermal emissions

Solving the problem of protecting the environment from the harmful effects of thermal power plants requires an integrated approach.

Location of TPP. A number of restrictions and technical requirements when choosing a site for construction is dictated by environmental considerations.

Firstly, the so-called pollution background, which arises in connection with the work in this zone of a number of industrial enterprises, and sometimes already existing power plants. If the magnitude of pollution at the site of the proposed construction has already reached or close to the limit values, the location of, for example, a thermal plant should not be allowed.

Secondly, in the presence of a certain, but not high enough pollution background, detailed assessments should be carried out to compare the values of possible emissions from the planned thermal plant with those already existing in the area. In this case, it is necessary to take into account factors of various nature and content: the direction, strength and frequency of winds in this area, the probability of precipitation, the absolute emissions of the station when operating on the proposed type of fuel, the instructions for the combustion devices, the indicators of emission purification and trapping systems, etc. After comparing the obtained total (taking into account the impact from the projected thermal plant) emissions with the maximum allowable, a final conclusion should be made on the feasibility of building a thermal power plant.

During the construction of power plants, primarily thermal power plants, in cities or suburbs, it is planned to create forest belts between the station and residential areas. They reduce the impact of noise on nearby areas, contribute to the retention of dust during winds in the direction of residential areas.

When designing and building thermal power plants, it is necessary to plan their equipping with highly efficient means of cleaning and recycling waste, discharges and emissions of pollutants, and the use of environmentally friendly fuels.

Air basin protection. Protection of the atmosphere from the main source of TPP pollution - sulfur dioxide - occurs primarily through its dispersion in the higher layers of the air basin. To do this, chimneys are built 180, 250 and even 420 m high. A more radical means of reducing sulfur dioxide emissions is the separation of sulfur from the fuel before it is burned at thermal power plants.

The most effective way to reduce sulfur dioxide emissions is the construction of limestone sulfur trapping plants at TPPs and the introduction of installations for the extraction of pyrite sulfur from coal at concentrating plants.

One of important documents in the protection of the atmosphere from thermal emissions on the territory of the Republic of Belarus is the Law of the Republic of Belarus "On the Protection of Atmospheric Air". The Law emphasizes that atmospheric air is one of the main vital important elements environment, the favorable state of which is the natural basis for sustainable socio-economic development of the republic. The law is aimed at preserving and improving the quality of atmospheric air, its restoration to ensure the environmental safety of human life, as well as preventing harmful effects on the environment. The law establishes the legal and organizational framework for the norms of economic and other activities in the field of the use and protection of atmospheric air.

Conclusion

The main danger of thermal power engineering for the atmosphere is that the combustion of carbon-containing fuels leads to the appearance of carbon dioxide CO2, which is released into the atmosphere and contributes to the greenhouse effect.

The presence of sulfur additives in the burning coal leads to the appearance of sulfur oxides, they enter the atmosphere and, after reacting with water vapor in the clouds, create sulfuric acid, which falls to the ground with precipitation. This is how acid precipitation with sulfuric acid occurs.

Another source of acid precipitation is nitrogen oxides, which occur in the furnaces of thermal power plants at high temperatures (at ordinary temperatures, nitrogen does not interact with atmospheric oxygen). Further, these oxides enter the atmosphere, react with water vapor in the clouds and create nitric acid which, along with precipitation, falls to the ground. This is how acid precipitation with nitric acid occurs.

A coal-fired thermal power plant that generates electricity with a capacity of 1 GW = 10 "W consumes 3 million coal annually, emitting 7 million tons of CO2, 120 thousand tons of sulfur dioxide, 20 thousand tons of nitrogen oxides NO2, and 750 thousand tons of nitrogen oxides into the environment. tons of ash.

Coal and fly ash contain significant amounts of radioactive impurities. An annual release into the atmosphere in the area of a 1 GW thermal power plant leads to the accumulation of radioactivity on the soil, which is 10-20 times higher than the radioactivity of annual emissions from a nuclear power plant of the same power.

Thus, the protection of the atmosphere from thermal emissions should be aimed at reducing the volume of gas emissions and their purification and include the following measures:

Monitoring the state of the environment;

Application of methods, methods and means that limit the volume of gas emissions and its supply to the field gas collection network;

Use in emergency cases of flare devices that ensure complete combustion of the discharged gas;

Ensuring compliance with environmental standards by the designed facilities and structures;

Application of the automatic blocking system technological flows in oil refining, which allows sealing hazardous areas in emergency situations and discharging this link into the flare system;

The maximum possible change in the fuel modes of thermal power plants in favor of environmentally friendly types of fuel and modes of its reduction;

Achievement of the main volume of reducing gas emissions in oil refining through the construction of installations for the treatment of associated and petroleum gas and gas pipeline systems that ensure utilization.

Reducing the volume of harmful emissions and oil refining is achieved in the process of reconstruction and modernization of the oil refining industry, accompanied by the construction of environmental facilities.

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