MAIN EDUCATIONAL PROGRAM
Preparation of bachelors in the direction
Protection environment»
CURRICULUM DISCIPLINE
"State exam"
PURPOSE OF THE STATE EXAM
The purpose of the final state examination of bachelors in the direction 280 200.62 "Environmental Protection" is to assess the development of professional competencies by graduates and competitive selection among persons wishing to master the program of specialized master's training.
STRUCTURE OF THE ENTRANCE EXAM
The state exam is interdisciplinary in nature and includes the material provided for by the State Educational Standard of Higher Professional Education for the preparation of bachelors of engineering and technology in the direction 280200.62 (553500) "Environmental Protection" and the OOP MITHT them. M.V. Lomonosov.
On the state exam the student is offered a task consisting of three questions, reflecting the basic qualification requirements for the disciplines studied. The list includes disciplines:
1. Fundamentals of toxicology.
2. Theoretical foundations of environmental protection.
3. Industrial ecology.
4. Rationing and control in the field of the environment.
5. Economics of nature management and environmental protection.
Discipline "Fundamentals of toxicology"
Basic concepts of toxicology (harmful substances, xenobiotics, poisons, toxicants; toxicity, danger, risk; poisoning or intoxication). Toximetry. Toxicometry parameters: mean lethal dose and mean lethal concentration, acute exposure threshold toxic substance, threshold of chronic exposure to the substance, zones of acute toxic and chronic action of the substance. Sections of toxicology (experimental, professional, clinical, ecological, etc.). Methods of toxicology.
General principles for the study of the toxicity of substances. Principles for the study of toxicity (acute, subacute and chronic) substances. Types of experimental animals and experimental conditions. Interpretation of the results of experimental studies. Special types of toxic effects of substances (carcinogenicity, mutagenicity, embryo- and fetotoxicity, etc.).
Classification of poisons (or toxicants) and poisonings. Principles of classification of poisons. General classification poisons: chemical, practical, hygienic, toxicological, according to "selectivity of toxicity". Special classification: pathophysiological, pathochemical, biological, specific biological consequences poisoning. Classification of poisonings ("chemical injury"): etiopathogenetic, clinical and nosological.
Ways of entry of poisons into the body. Toxic-kinetic features of oral, inhalation and percutaneous poisoning. Distribution of poisons in the body. Deposit.
Factors affecting the distribution of poisons. Volume of distribution as a toxicokinetic characteristic of a toxicant.
Biotransformation of poisons as a process of detoxification of the body. Enzymatic biotransformation systems. General representations about enzymes. Substrate-enzyme interaction. Specific and non-specific enzymes. Microsomal and non-microsomal biotransformation enzymes.
toxic effects. Localization of the toxic effect of substances. Mechanisms of toxic action. Combined effects of substances on the body: additive effect, synergism, potentiation, antagonism.
Removal (excretion) of substances from the body. renal excretion. Other ways of removing substances from the body (through the intestines, through the lungs, through the skin). The immune system as a way to detoxify macromolecules. Intersystem cooperation of detoxification and excretion.
detox methods. Detoxification methods based on knowledge of the toxicological properties of substances. Toxicokinetic method of detoxification (influence on absorption, distribution, biotransformation and elimination of harmful substances). Toxicodynamic method of detoxification.
specific chemicals. Air, water, soil pollutants. Carbon monoxide, sulfur dioxide, nitrogen oxides, ozone, etc. Solvents; halogenated hydrocarbons, aromatic hydrocarbons. Insecticides (chlorinated hydrocarbons, organophosphate, carbamate, vegetable). Herbicides (chlorophenolic, dipyridyl). Polychlorinated biphenyls, dibenzodioxins and dibenzofurans, dibenzothiophenes. The specifics of the impact on the body of radioactive substances.
Discipline "Theoretical foundations of environmental protection"
Natural sources of environmental impact (OS). Comparative assessment of factors affecting the OS. Concepts and criteria for studying substances: volume of production, areas of application, distribution in the environment, stability and ability to decompose, transformations. Concepts and criteria for studying natural environments: atmosphere. Dust and aerosols: characteristics of pollution, occurrence, residence time in the atmosphere. The state of pollution in the atmosphere.
Pollution of the atmosphere with gases. Issues of emissions, transfer and penetration into the body. carbon monoxide. Conditions of anthropogenic emissions, physiological features, chemical reactions in the atmosphere. Carbon dioxide. The carbon cycle. Models of the possible development of the "greenhouse" effect. Issues of distribution, chemical behavior in the atmosphere, localization and physiological features for sulfur dioxide and nitrogen oxides. Fluorochlorohydrocarbons. atmospheric ozone.
Water distribution. Dynamics of water consumption. Assessment of water pollution.
organic remains. Substances destroyed by microorganisms and changes in the state of water. Stable or hard-to-break substances.
Surfactants (main types, features of chemical transformation in the hydrosphere). Inorganic residues: (fertilizers, salts, heavy metals). Alkylation processes.
Overview of the main methods of water purification. Branch concepts and criteria. Industries chemical industry. Waste water treatment and waste disposal systems.
Lithosphere. The structure and composition of soils. Anthropogenic pollution. Losses nutrients soil. Soil as an integral part of the landscape and living space. Issues and methods of soil reclamation.
Sources of artificial radionuclide in OS. Radioecology. Impact electromagnetic radiation. Basic concepts and terms. Electromagnetic fields of industrial frequency, HF and microwave ranges. Protective equipment.
Noise (sound) in the OS. Basic concepts. Noise propagation. Methods for assessing and measuring noise pollution. General methods to reduce noise pollution. Influence of vibration on the person and OS. Causes and sources of vibrations. Rationing. Carrying out acoustic calculation.
Man has had an impact on the environment since ancient times. The constant economic development of the world improves human life and expands it natural environment habitats, but the condition of limited natural resources and physical capabilities remains unchanged. The creation of specially protected areas, the ban on hunting and deforestation are examples of restrictions on such impacts that have been introduced since ancient times. However, it was only in the 20th century that the scientific substantiation of this impact, as well as the problems that arose as a result, and the development of rational decision taking into account the interests of present and future generations.
In the 1970s, many scientists devoted their work to the issues of limited natural resources and environmental pollution, emphasizing their importance for human life.
For the first time, the term "ecology" was used by the biologist E. Haeckel: "By ecology, we mean general science about the relationship between the organism and the environment, where we include all the "conditions of existence" in broad sense this word." ("General morphology of organisms", 1866)
The modern definition of the concept of ecology has a broader meaning than in the first decades of the development of this science. The classical definition of ecology is the science that studies the relationship between living and non-living things. http://www.werkenzonderdiploma.tk/news/nablyudaemomu-v-nastoyaschee-83.html
Two alternative definitions of this science:
Ecology - knowledge of the economy of nature, the simultaneous study of all the relationships of living things with organic and inorganic components environment ... In a word, ecology is a science that studies all the complex relationships in nature, considered by Darwin as conditions for the struggle for existence.
· Ecology -- biological science, which explores the structure and functioning of superorganismal level systems (populations, communities, ecosystems) in space and time, in natural and human-modified conditions.
Ecology in scientific works logically moved into the concept sustainable development.
Sustainable development - ecological development- involves meeting the needs and aspirations of the present without undermining the ability of future generations to meet their needs. Transition to the era of sustainable development., R.A. flight, s. 10-31 // Russia in the surrounding world: 2003 (Analytical Yearbook). - M.: Publishing house MNEPU, 2003. - 336 p. http://www.rus-stat.ru/index.php?vid=1&id=53&year=2003 As this environmental concern has become greater over the past decades, concern for the fate of future generations and a fair distribution of natural resources between generations has become more and more evident.
The concept of biological diversity - biodiversity - is interpreted as the diversity of life forms, expressed through millions of species of plants, animals and microorganisms, together with their genetic pool and complex ecosystem.
Maintaining biodiversity is currently a global need for at least for three reasons. The main reason is that all species have the right to live in the conditions that are peculiar to them. Second, multiple life forms maintain the chemical and physical balance on Earth. Finally, experience shows that maintaining a maximum genetic pool is of economic interest to agriculture and the medical industry.
Today, many countries are faced with the problem of environmental degradation and the need to prevent further development of this process. Economic development leads to environmental problems, causes chemical pollution, and damages natural habitats. There is a threat to human health, as well as the existence of many species of flora and fauna. The problem of limited resources is becoming more and more acute. Future generations will no longer have the natural resources that previous generations had.
To solve a series environmental issues in the European Union, energy-saving technology is used; in the USA, emphasis is placed on bioengineering. At the same time, developing countries and countries with economies in transition have not realized the importance of environmental impact. Often the solution of problems in these countries occurs under the influence of external forces, rather than government policy. This attitude may lead to greater increase gap between developed and developing countries and, last but not least, to increased environmental degradation.
Summing up, it should be noted that with economic development and the development of new technologies, the state of ecology is also changing, and the threat of environmental degradation is increasing. At the same time, new technologies are being created to solve environmental problems.
1. General principles for the dispersion of pollutants in the atmosphere.
2. Scattering calculation mechanism harmful emissions industrial enterprises.
3. Theory of NO x formation during fossil fuel combustion.
4. The theory of the formation of sooty particles during the combustion of fossil fuels.
5. The theory of the formation of gas-formed underburning in boiler furnaces.
6. The theory of SO x formation during fossil fuel combustion.
7. Reduced NO x emissions.
8. Reducing the emission of SO x.
9. Reduced aerosol emissions.
10. Basic principles of the transfer of pollution in the atmosphere.
11. Influence of thermophysical and aerodynamic factors on the processes of heat and mass transfer in the atmosphere.
12. Basic provisions of the theory of turbulence from classical hydrodynamics.
13. Application of the theory of turbulence to atmospheric processes.
14. General principles of dispersion of pollutants in the atmosphere.
15. Spread of pollutants from the pipe.
16. Basic theoretical approaches used to describe the processes of dispersion of impurities in the atmosphere.
17. Calculation method for the dispersion of harmful substances in the atmosphere, developed in GGO them. A.I. Voeikov.
18. General patterns dilution of wastewater.
19. Methods for calculating the dilution of wastewater for watercourses.
20. Methods for calculating the dilution of wastewater for reservoirs.
21. Calculation of the maximum allowable discharge for flowing water bodies.
22. Calculation of the maximum allowable discharge for reservoirs and lakes.
23. The movement of aerosol pollutants in the stream.
24. Theoretical foundations for capturing solid particles from exhaust gases.
25. Theoretical foundations of environmental protection from energy impacts.
Literature
1. Kulagina T.A. Theoretical foundations of environmental protection: Textbook. allowance / T.A. Kulagin. 2nd ed., revised. And extra. Krasnoyarsk: IPTs KSTU, 2003. - 332 p.
Compiled by:
T.A. Kulagina
Section 4. ENVIRONMENTAL IMPACT ASSESSMENT AND Ecological Expertise
1. The system of environmental assessment, the subject, goals and main objectives of the course and the concept of the course, types of environmental assessments. Differences between environmental expertise (EE) and environmental impact assessment (EIA).
2. Development of a system of environmental support for the project, life cycle project, ESHD.
3. Environmental support economic activity investment projects (differences in approaches, categories).
4. Legal and normative-methodical base of ecological expertise and EIA in Russia.
5. Classification of EE and EIA objects by types of nature management, by the type of exchange of matter and energy with the environment, by the degree of environmental hazard for nature and humans, by the toxicity of substances.
6. Theoretical foundations of environmental expertise (goals, objectives, principles, types and types of state environmental expertise, interaction matrix).
7. Subjects and objects of state environmental expertise.
8. Methodological provisions and principles of environmental design ..
9. The procedure for organizing and conducting environmental procedures (grounds, case, conditions, aspects, procedure for the State Environmental Expertise and its regulations for conducting).
10. List of documentation submitted for state environmental expertise (on the example of the Krasnoyarsk Territory).
11. The procedure for preliminary consideration of documentation submitted to the SEE. Registration of the conclusion of the state ecological expertise (composition of the main parts).
13. Public ecological expertise and its stages.
14. Principles of environmental assessment. The subject of environmental assessment.
15. Legal Framework environmental assessment and specially authorized bodies (their functions). Participants in the environmental assessment process, their main tasks.
16. Stages of the environmental assessment process. Methods and systems for selecting projects.
17. Methods for identifying significant impacts, matrices for identifying impacts (schemes).
18. The structure of the EIA and the method of organizing the material, the main stages and aspects.
19. Environmental requirements for the development of regulations, environmental criteria and standards.
20. Standards for environmental quality and permissible impact, use of natural resources.
21. Rationing of sanitary and protective zones.
22. Information base of ecological design.
23. Public participation in the EIA process.
24. Assessment of the impact of the investigated economic object on the atmosphere, direct and indirect criteria for assessing atmospheric pollution.
25. Procedure for conducting EIA (stages and procedures of EIA).
Literature
1. Law of the Russian Federation "On the Protection of the Environment" dated January 10, 2002 No. 7-FZ.
2. Law of the Russian Federation "On Ecological Expertise" dated November 23, 1995 No. 174-FZ.
3. Regulation “On Environmental Impact Assessment in the Russian Federation”. / Approved Order of the Ministry of Natural Resources of the Russian Federation of 2000 No.
4. Guidelines for the environmental review of pre-project and project documentation. / Approved. Head of Glavgosekoekspertiza dated 10.12.93. Moscow: Ministry of Natural Resources. 1993, 64 p.
5. Fomin S.A. "State Ecological Expertise". / In the book. Environmental law of the Russian Federation. // Ed. Yu.E. Vinokurov. - M.: Publishing house of MNEPU, 1997. - 388 p.
6. Fomin S.A. "Ecological Expertise and EIA". / In the book. Ecology, nature protection and ecological safety. // Under the general editorship. IN AND. Danilova-Danilyana. - M.: Publishing House of MNEPU, 1997. - 744 p.
Compiled by:
Candidate of Technical Sciences, Associate Professor of the Department of Engineering Ecology
and life safety"
STATE EDUCATIONAL INSTITUTION OF HIGHER PROFESSIONAL EDUCATION
MOSCOW STATE TECHNOLOGICAL UNIVERSITY "STANKIN"
FACULTY OF TECHNOLOGY
DEPARTMENT OF ENVIRONMENTAL ENGINEERING AND LIFE SAFETY
Doctor of Physics and Mathematics. sciences, professor
M.YU.KHUDOSHINA
THEORETICAL FOUNDATIONS OF ENVIRONMENTAL PROTECTION
LECTURE NOTES
MOSCOW
Introduction.
Environmental protection methods. Greening industrial production
Methods and means of environmental protection.
The environmental protection strategy is based on objective knowledge about the laws of functioning, relationships and development dynamics of the constituent elements of the environment. They can be obtained through scientific research within the framework of various fields of knowledge - natural sciences, mathematical, economic, social, public. On the basis of the regularities obtained, methods for protecting the environment are developed. They can be divided into several groups:
Propaganda methods
These methods are devoted to promoting the protection of nature and its individual elements. The purpose of their application is to form an ecological outlook. Forms: oral, printed, visual, radio and television. To achieve the effectiveness of these methods are used scientific developments in the field of sociology, psychology, pedagogy, etc.
Legislative Methods
The fundamental laws are the constitution, it fixes the main tasks and obligations of a citizen in relation to the environment, as well as the Law on ... Legal protection of land is provided by land legislation (Fundamentals ... Legal protection of subsoil (subsoil legislation, Subsoil Code) establishes state ownership of subsoil, …These methods include state and local organizational measures aimed at expedient, from the point of view of environmental protection, placement on the territory of enterprises, production and settlements, as well as on the solution of single and complex environmental problems and issues. Organizational methods ensure the holding of mass, state or international economic and other events aimed at creating effective conditions environment. For example, the transfer of logging from the European part to Siberia, the replacement of wood with reinforced concrete and the saving of natural resources.
These methods are based on system analysis, control theory, simulation modeling, etc.
Technical Methods
They determine the degree and types of impact on the object of protection or its surrounding conditions in order to stabilize the state of the object, including:
- Termination of impact on protected objects (order, conservation, prohibition of use).
Reduction and reduction of exposure (regulation), volume of use, harmful effects through the purification of harmful emissions, environmental regulation, etc.
· Reproduction of biological resources.
· Restoration of depleted or destroyed objects of protection (natural monuments, populations of plants and animals, biocenoses, landscapes).
· Strengthening the use (use in the protection of rapidly breeding commercial populations), rarefaction of populations to reduce mortality from infectious diseases.
· Changing forms of use in the protection of forests and soils.
Domestication (Przewalski's horse, eider, bison).
· Fencing with fences and nets.
· Various methods of soil protection from erosion.
The development of methods is based on fundamental and scientific and applied developments in the field of natural sciences, including chemistry, physics, biology, etc.
Technical and economic methods
- Development and improvement of treatment facilities.
- Implementation of non-waste and low-waste industries and technologies.
- Economic methods: obligatory payments for environmental pollution; payments for natural resources; fines for violation environmental legislation; budget financing of state environmental programs; systems of state environmental funds; environmental insurance; a set of measures for economic stimulation of environmental protection .
Such methods are developed on the basis of applied disciplines, taking into account technical, technological and economic aspects.
Section 1. Physical bases of purification of industrial gases.
Topic 1. Directions for the protection of the air basin. Difficulties in cleaning gases. Features of air pollution
Air basin protection directions.
Sanitary - technical measures.
Installation of gas and dust cleaning equipment,
Installation of ultra-high pipes.
The criterion for the quality of the environment is the maximum permissible concentration (MAC).
2. Technological direction .
Creation of new methods for the preparation of raw materials, purifying it from impurities before being involved in production,
Creation of new technologies based in part or in full
closed cycles
Replacement of raw materials, replacement of dry methods of processing dusty materials with wet ones,
Automation of production processes.
planning methods.
Installation of sanitary protection zones, which are regulated by GOST and building codes,
The optimal location of enterprises, taking into account the wind rose,
- removal of toxic production facilities outside the city limits,
Rational planning city building,
Landscaping.
Control and prohibitive measures.
Maximum allowable concentration,
Maximum allowable emissions,
Emission control automation,
Prohibition of certain toxic products.
Difficulties in cleaning gases
The problem of cleaning industrial gases is primarily due to the following reasons:
· Gases are diverse in their composition.
· Gases have a high temperature and a large volume of dust.
· The concentration of ventilation and process emissions is variable and low.
The use of gas cleaning plants requires their continuous improvement
Features of air pollution
First of all, they include the concentration and disperse composition of dust. Usually 33-77% of the volume of pollution are particles up to 1.5 in size ... Atmospheric inversions Normal temperature stratification is determined by the conditions when an increase in height corresponds to a decrease ...Topic 2. Requirements for treatment facilities. Structure of industrial gases
Requirements to treatment facilities. The cleaning process is characterized by several parameters. 1. Overall cleaning efficiency (n):The structure of industrial gases.
Industrial gases and air containing solid or liquid particles are two-phase systems consisting of a continuous (continuous) medium - gases and dispersed phase(solid particles and liquid droplets), such systems are called aerodispersed or aerosols. Aerosols are divided into three classes: dusts, fumes, fogs.
Dust.
Consists of solid particles dispersed in a gaseous medium. Formed as a result of mechanical grinding solids into powders. These include: aspiration air from crushing, grinding, drilling units, transport devices, sandblasting machines, machine tools for mechanical processing of products, powder packaging departments. These are polydisperse and unstable systems with particle sizes of 5-50 µm.
Smokes.
These are aerodisperse systems consisting of particles with low vapor pressure and low sedimentation rate. They are formed during sublimation and condensation of vapors as a result of chemical and photochemical reactions. The particle size in them is from 0.1 to 5 microns and less.
fogs.
Consist of liquid droplets dispersed in a gaseous medium, which may contain dissolved substances or suspended solids. They are formed as a result of condensation of vapors and when a liquid is sprayed into a gaseous medium.
Topic 3. Main directions of gas flow hydrodynamics. Continuity equation and Navier-Stokes equation
Fundamentals of gas flow hydrodynamics.
Consider the action of the main forces on the elementary volume of gas (Fig. 1).
Rice. 1. The action of forces on an elementary volume of gas.
The theory of gas flow movement is based on two basic equations of hydrodynamics: the continuity (continuity) equation and the Navier-Stokes equation.
Continuity equation
∂ρ/∂τ + ∂(ρ x V x)/∂x + ∂(ρ y V y)/∂y + ∂(ρ z V z)/∂z = 0 (1)
where ρ is the density of the medium (gases) [kg/m3]; V - speed of gas (medium) [m/s]; V x , V y , V z are the component velocity vectors along the X, Y, Z coordinate axes.
This equation is the Law of Conservation of Energy, according to which a change in the mass of a certain elementary volume of gas is compensated by a change in density (∂ρ/∂τ).
If ∂ρ/∂τ = 0 - steady motion.
Navier-Stokes equation.
– ∂px/∂x + μ(∂2Vx/∂x2 + ∂2Vx/∂y2 + ∂2Vx/∂z2) = ρ (∂Vx/∂τ +… – ∂py/ ∂y + μ(∂2Vy/∂ x2 + ∂2Vy/∂y2 + ∂2Vy/∂z2) =…Border conditions
. Fig.2 Gas flow around the cylinder.Initial conditions
To characterize the state of the system in initial moment time set the initial conditions.
Boundary conditions
The boundary and initial conditions constitute the boundary conditions. They highlight the space-time region and ensure the unity of the solution.
Topic 4. Criterial equation. Turbulent flow of liquid (gas). boundary layer
Equations (1) and (2) form a system with two unknowns - V r (gas velocity) and P (pressure). It is very difficult to solve this system, so simplifications are introduced. One such simplification is the use of similarity theory. This makes it possible to replace system (2) with one criterion equation.
criterion equation.
f(Fr, Eu, Re r) = 0
These criteria Fr, Eu, Re r are based on experiments. View functional connection established by experience.
Froude criterion
It characterizes the ratio of the force of inertia to the force of gravity:
Fr \u003d Vg 2 / (gℓ)
where Vg 2 - the force of inertia; gℓ- force of gravity; ℓ - defining linear parameter, determines the scale of gas movement [m].
The Froude criterion plays an important role when the moving flow system is significantly affected by gravitational forces. When solving many practical problems, the Froude criterion degenerates, since gravity is taken into account.
Euler criterion(secondary):
Eu = Δp/(ρ g V g 2)
where Δp - pressure drop [Pa]
The Euler criterion characterizes the ratio of the pressure force to the force of inertia. It is not decisive and is regarded as secondary. Its form is found by solving equation (3).
Reynolds criterion
It is the main one and characterizes the ratio of inertial forces to the friction force, turbulent and rectilinear motion.
Re r = V g ρ g ℓ / μ g
where μ is the dynamic viscosity of the gas [Pa s]
The Reynolds criterion is the most important characteristic of the gas flow movement:
- at low values of the Reynolds criterion Re, friction forces predominate, and a stable rectilinear (laminar) gas flow is observed. The gas moves along the walls that determine the flow direction.
- with increasing Reynolds number laminar flow loses stability and, at a certain critical value of the criterion, passes into the turbulent regime. In it, turbulent masses of gas move in any direction, including the direction of the wall and the body in a flow.
Turbulent fluid flow.
Automodel mode.
Turbulent pulsations - determined by the speed and scale of movement. Movement scales: 1. The fastest pulsations have the largest scale 2. When moving in a pipe, the scale of the largest pulsations coincides with the pipe diameter. The magnitude of the ripple is determined ...Pulsation speed
Vλ = (εnλ / ρg)1/3 2. A decrease in the speed and scale of the pulsation corresponds to a decrease in the number ... Reλ = Vλλ / νg = Reg(λ/ℓ)1/3Automodel mode
ξ = A Reg-n where A, n are constants. With an increase in inertial forces, the exponent n decreases. The more intense the turbulence, the smaller n.…boundary layer.
1. According to the Prandtl-Taylor hypothesis, the motion in the boundary layer is laminar. Due to the absence of turbulent motion, the transfer of matter ... 2. In the boundary layer, turbulent pulsations gradually decay, approaching ... In the diffuse sublayer z<δ0, у стенки молекулярная диффузия полностью преобладает над турбулентной.Topic 5. Properties of particles.
Basic properties of suspended particles.
I. Density of particles.
The density of particles can be true, bulk, apparent. Bulk density takes into account the air gap between dust particles. When caking, it increases by 1.2-1.5 times. Apparent density is the ratio of the mass of a particle to the volume it occupies, including pores, voids, and irregularities. A decrease in the apparent density in relation to the true one is observed in dust prone to coagulation or sintering of primary particles (soot, non-ferrous metal oxides). For smooth monolithic or primary particles, the apparent density coincides with the true one.
II. Dispersion of particles.
Particle size is determined in several ways: 1. Clear size - the smallest size of the sieve openings through which more ... 2. The diameter of spherical particles or the largest linear size of particles of irregular shape. It is applied in…Distribution types
Different workshops have different composition of emitted gases, different composition of contaminants. The gas must be examined for the content of dust, consisting of particles of various sizes. To characterize the disperse composition, the percentage distribution of particles per unit volume by the number f(r) and by mass g(r) is used, respectively, counting and mass distributions. Graphically, they are characterized by two groups of curves - differential and integral curves.
1. Differential distribution curves
A) countable distribution
The fractions of particles whose radii are in the interval (r, r+dr) and obey the function f(r) can be represented as:
f(r)dr=1
The distribution curve that can describe this function f(r) is called the differential distribution curve of particles according to their size according to the number of particles (Fig. 4).
Rice. 4. Differential curve of aerosol particle size distribution according to their number.
B) Mass distribution.
Similarly, we can represent the particle mass distribution function g(r):g(r)dr=1
It is more convenient and popular in practice. The form of the distribution curve is shown in the graph (Fig. 5).
0 2 50 80 µm
Rice. Fig. 5. Differential curve of distribution of aerosol particles by size by their mass.
Integral distribution curves.
D(%) 0 10 100 µm Fig. 6. Integral curve of passagesInfluence of dispersion on the properties of particles
The dispersion of particles affects the formation of the free energy of the surface and the degree of stability of aerosols.
Free energy of the surface.
WednesdaySurface tension.
Aerosol particles, due to their large surface, differ from the starting material in some properties that are important for the practice of dedusting.
The surface tension for liquids at the interface with air is now precisely known for various liquids. It is, for example, for:
Water -72.5 N cm. 10 -5 .
For solids, it is significant and numerically equal to the maximum work expended on the formation of dust.
There are very few gases.
If the molecules of a liquid interact with the molecules of a solid more strongly than with each other, the liquid spreads over the surface of the solid, wetting it. Otherwise, the liquid collects into a drop, which would have a round shape if gravity did not act.
Scheme of the wettability of rectangular particles.
The diagram (Fig. 11) shows:
a) immersion of a wetted particle in water:
b) immersion in water of a non-wettable particle:
Fig.11. Wetting scheme
The wetting perimeter of particles is the boundary of the interaction of three media: water (1), air (2), solid body (3).
These three environments have delimiting surfaces:
Liquid-air surface with surface tension δ 1.2
Air-solid surface with surface tension δ 2.3
Surface "liquid - solid" with surface tension δ 1.3
Forces δ 1.3 and δ 2.3 act in the plane of a solid body per unit length of the wetting perimeter. They are directed tangentially to the interface and perpendicular to the wetting perimeter. The force δ 1.2 is directed at an angle Ө, called the contact angle (wetting angle). If we neglect the force of gravity and the lifting force of water, then when an equilibrium angle Ө is formed, all three forces are balanced.
The equilibrium condition is determined Young's formula :
δ 2.3 = δ 1.3 + δ 1.2 cos Ө
Angle Ө varies from 0 to 180°, and Cos Ө varies from 1 to –1.
At Ө >90 0, the particles are poorly wetted. Complete non-wetting (Ө = 180°) is not observed.
Wetted (Ө >0°) particles are quartz, talc (Ө =70°) glass, calcite (Ө =0°). Non-wettable particles (Ө = 105°) are paraffin.
Wetted (hydrophilic) particles are drawn into the water by the force of surface tension acting at the water-air interface. If the particle density less density water, gravity is added to this force, and the particles sink. If the density of the particle is less than the density of water, then the vertical component of the surface tension forces decreases by the lifting force of the water.
Non-wettable (hydrophobic) particles are supported on the surface by surface tension forces, the vertical component of which is added to the lift force. If the sum of these forces exceeds the force of gravity, then the particle remains on the surface of the water.
Water wettability affects the efficiency of wet dust collectors, especially when working with recirculation - smooth particles are wetted better than particles with an uneven surface, as they are in more covered with an absorbed gaseous membrane that makes wetting difficult.
According to the nature of wetting, three groups of solids are distinguished:
1. hydrophilic materials that are well wetted by water are calcium,
most silicates, quartz, oxidizable minerals, alkali halides
metals.
2. hydrophobic materials poorly wetted by water - graphite, sulfur coal.
3. absolutely hydrophobic bodies are paraffin, teflon, bitumen. (Ө~180 o)
IV. Adhesion properties of particles.
Fad = 2δd where δ - surface tension at the boundary between solid and air. The adhesion force is directly proportional to the first power of the diameter, and the force that breaks the aggregate, for example, gravity or ...V. Abrasiveness
Abrasiveness is the intensity of metal wear, at the same gas velocities and dust concentrations.
The abrasive properties of the particles depend on:
1. hardness of dust particles
2. shape of dust particles
3. dust particle size
4. Density of dust particles
The abrasive properties of the particles are taken into account when choosing:
1. velocity of dusty gases
2. wall thicknesses of apparatuses and flue gases
3. facing materials
VI. Hygroscopicity and solubility of particles.
Depends on:
1. chemical composition of dust
2. Dust particle chamber
3. shape of dust particles
4. The degree of surface roughness of dust particles
These properties are used to trap dust in wet type apparatuses.
VII. Electrical Properties dust.
Electrical contamination of particles.
Behavior in waste gases Collection efficiency in gas cleaning devices (electric filter) … Explosion hazardIX. The ability of dust to self-ignite and form explosive mixtures with air.
There are three groups of substances, according to the causes of ignition: 1. Substances that ignite spontaneously when exposed to air. The cause of the fire is oxidation under the influence of atmospheric oxygen (heat is released at low ...self-ignition mechanism.
Due to the highly developed contact surface of particles with oxygen, combustible dust is capable of spontaneous combustion and the formation of explosive mixtures with air. The intensity of a dust explosion depends on:
Thermal and chemical properties dust
Size and shape of dust particles
Dust particle concentrations
Composition of gases
Dimensions and temperatures of ignition sources
Relative content of inert dust.
When the temperature rises, ignition may occur spontaneously. Productivity, burning intensity can be different.
Intensity and duration of burning.
Dense masses of dust burn more slowly, since the access of oxygen to them is difficult. Loose and small masses of dust ignite in the entire volume. When the oxygen concentration in the air is less than 16%, the dust cloud does not explode. The more oxygen, the more likely the explosion and the greater its strength (at the enterprise when welding, when cutting metal). Minimum explosive concentrations of airborne dust - 20-500g / m 3, maximum - 700-800 g / m 3
Topic 6. Main mechanisms of particle deposition
The operation of any dust collecting apparatus is based on the use of one or more mechanisms for the deposition of particles suspended in gases. 1. Gravitational settling (sedimentation) occurs as a result of ... 2. Settling under the action of centrifugal force. It is observed during the curvilinear motion of an aerodispersed flow (flow ...Gravitational settling (sedimentation)
F= Sch, where is the drag coefficient of the particle; S h is the cross-sectional area of the particle, perpendicular to the motion; Vh - ...Centrifugal particle settling
F=mch, V= t m – particle mass; V is the speed; r is the radius of rotation; t- relaxation time Settling time of suspended particles in centrifugal dust collectors is directly proportional to the square of the particle diameter.…Influence of the Reynolds criterion on inertial settling.
2. With an increase in the Reynolds criterion, upon transition to turbulent motion, a boundary layer is formed on the surface of the streamlined body. As… 3. For values of the criterion greater than the critical value (500), the streamlines are stronger… 4. With developed turbulence approaching the self-similar regime, the Reynolds criterion can be ignored. AT…Engagement.
Thus, the deposition efficiency of this mechanism is higher than 0, and when there is no inertial deposition, the engagement effect is characterized by ... R = dh / dDiffusion deposition.
where D is the diffusion coefficient, characterizes the effectiveness of the Brownian ... The ratio of internal friction forces to diffusion forces is characterized by the Schmidt criterion:Deposition under the action of elementary charges
Elementary charging of particles can be carried out in three ways: 1. During the generation of aerosols 2. Due to the diffusion of free ionsThermophoresis
This is the repulsion of particles by heated bodies. It is caused by forces acting from the side of the gaseous phase on the non-uniformly heated ones in it ... If the particle size is more than 1 micron, the ratio of the final speed of the process to ... Note: a negative side effect occurs when solid particles settling from hot gases onto cold ...Diffusiophoresis.
This movement of particles is caused by the concentration gradient of the components gas mixture. Manifested in the processes of evaporation and condensation. When evaporating with...Settling of particles in a turbulent flow.
Turbulent fluctuation velocities increase, vortex diameters decrease, and small-scale fluctuations perpendicular to the wall already appear on…Use of an electromagnetic field for the sedimentation of suspended particles.
When gases move in a magnetic field, a particle is acted upon by a force directed at a right angle and in the direction of the field. As a result of such exposure… The total efficiency of particle trapping under the influence various mechanisms deposition.Topic 7. Coagulation of suspended particles
The approach of particles can occur due to brownian motion(thermal coagulation), hydrodynamic, electrical, gravitational and others ... The rate of decrease in the countable concentration of particlesSection 3. Mechanisms for the spread of pollution in the environment
Topic 8. Mass transfer
The spread of pollution in the environment (Fig. 13) occurs mainly due to natural processes and depends on the physico-chemical properties of substances, physical processes associated with their transfer, biological processes involved in global processes circulation of substances, cyclic processes in individual ecosystems. The tendency of substances to spread is the cause of the uncontrolled regional accumulation of substances.
A - atmosphere
G - hydrosphere
L - lithosphere
F - animals
H - man
P - plants
Rice. 13. Scheme of mass transfer in the biosphere.
In the ecosphere, in the process of transfer, the physicochemical properties of molecules, vapor pressure, and solubility in water primarily play a role.
Mass transfer mechanisms
Diffusion is characterized by the diffusion coefficient [m2/s] and depends on the molecular properties of the solute (relative diffusion) and… Convection is the forced movement of solutes by the flow of water.… Dispersion is the redistribution of solutes caused by the inhomogeneity of the flow velocity field.Soil - water
The spread of pollution in the soil occurs mainly due to natural processes. They depend on the physical and chemical properties of substances, physical ... Soil-water interface plays an important role in the transfer process. Basic…Langmuir equation
x/m is the ratio of the mass of the adsorbed substance to the mass of the adsorbent; and - constants characterizing the considered system; is the equilibrium concentration of a substance in a solution.
Freundlich isothermal adsorption equation
K is the adsorption coefficient; 1/n - characteristic of the degree of adsorption The second equation is used mainly to describe the distribution ...Topic 9. Receipt and accumulation of substances in living organisms. Other types of transfer
Any substance is absorbed and assimilated by living organisms. The steady state concentration is the saturation concentration. If it is higher than in ... The processes of accumulation of substances in the body: 1. Bioconcentration - enrichment chemical compounds organism as a result of direct replenishment from the environment ...Topic 10. Models of impurity propagation in media
Models of impurity distribution in the aquatic environment
Distribution of pollutants in the atmosphere.
Calculation of dispersion in the atmosphere of harmful substances contained in emissions ... Criteria for assessing atmospheric pollution.Methods for cleaning industrial emissions from gaseous pollution.
There are the following main methods:
1. Absorption- flushing of emissions with solvents of impurities.
2. Chemisorption- flushing of emissions with solutions of reagents that bind at
mixes chemically.
3. Adsorption- absorption gaseous impurities solid active ingredients.
Thermal neutralization of exhaust gases.
biochemical methods.
In gas purification technology, adsorption processes are called scrubber processes. The method consists in the destruction of gas-air mixtures into its constituent parts by... Organizing the contact of a gas stream with a liquid solvent is carried out: ... · Passing gas through a packed column.physical adsorption.
Its mechanism is as follows:
Gas molecules stick to the surface of solids under the action of intermolecular forces of mutual attraction. The heat released in this case depends on the force of attraction and coincides with the heat of steam condensation (reaches up to 20 kJ / m 3). In this case, the gas is called an adsorbate, and the surface is an adsorbent.
Advantages This method is reversible: with increasing temperature, the absorbed gas is easily desorbed without changing the chemical composition (this also occurs with decreasing pressure).
Chemical adsorption (chemisorption).
The disadvantage of chemisorption is that in this case it is irreversible, the chemical composition of the adsorbate changes. As an adsorbate, choose ... Adsorbents can be both simple and complex oxides (activated ...Section 4. Theoretical foundations for the protection of the hydrosphere and soil
Topic 11. Theoretical foundations for the protection of the hydrosphere
Industrial waste water
According to the nature of pollution, industrial wastewater is divided into acid-base, containing heavy metal ions, chromium, fluorine, and cyanide. Acid-alkaline wastewater is formed from the processes of degreasing, chemical etching, applying various coatings.
Reagent method
At the stage of pre-treatment of wastewater, various oxidizing agents, reducing agents, acids and alkaline reagents are used, both fresh and ... Post-treatment of wastewater can be carried out on mechanical and carbon filters. …Electrodialysis.
With this method, wastewater is treated electrochemically using chemical reagents. The quality of purified water after electrodialysis can be close to distilled. It is possible to purify waters with a variety of chemical contaminants: fluoride, chromium, cyanides, etc. Electrodialysis can be used before ion exchange to maintain a constant salt content of water, during the regeneration of waste solutions and electrolytes. The disadvantage is a significant consumption of electricity. Commercially available electrodialysis units such as EDU, ECHO, AE, etc. are used. (capacity from 1 to 25m 3 /h).
Water purification from oil products
International Convention of 1954 (as amended in 1962, 1969, 1971) for the Prevention of Marine Pollution by Oil established a ban on the discharge of bilge and ballast water containing oil products overboard within the coastal zone (up to 100-150 miles) with a concentration of more than 100 mg / l). The following maximum permissible concentrations (MPCs) of oil products in water have been established in Russia: high-sulfur oil products - 0.1 mg/l, non-sulphurous oil products - 0.3 mg/l. Concerning great importance for environmental protection is the development and improvement of methods and means of water purification from oil products contained in it.
Methods of purification of oily waters.
_Coalescence. This is the process of particle enlargement due to their merging. Coarseness of oil particles can take place spontaneously when they ... Some increase in the rate of coalescence can be obtained by heating ... Coagulation. In this process, particles of petroleum products are coarsened when various ...Topic 12. Theoretical foundations of soil protection
The theoretical foundations of soil protection include, among other things, the issues of the movement of contaminants in the soil for regions with different… The model of the distribution of contaminants in the soilRice. 14. Types of waste disposal
a - dump type of burial; b - burial on the slopes; in - burial in pits; G - burial in an underground bunker; 1 - waste; 2 - waterproofing; 3 - concrete
Disadvantages of dump type burials: difficulty in assessing the stability of slopes; high shear stresses at the base of slopes; the need to use special building structures to increase the stability of the burial; aesthetic load on the landscape. Burials on the slopes in contrast to the considered burials of the dump type, they require additional protection of the body of the burial from slipping and from being washed away by water flowing down the slope.
Burial in pits in lesser degree affects the landscape and does not pose a sustainability hazard. However, it requires the removal of water using pumps, since the base is located below the surface of the earth. Such disposal creates additional difficulties for waterproofing the side slopes and the base of the waste disposal site, and also requires constant monitoring of drainage systems.
Burials in underground bunkers in all respects more convenient and environmentally friendly, however, due to the high capital costs of their construction, they can only be used to remove small amounts of waste. Underground burial is widely used for isolation radioactive waste, as it allows, under certain conditions, to ensure radioecological safety for the entire required period and is the most cost-effective way to handle them. Waste should be deposited at the landfill in layers no thicker than 2 m, with obligatory compaction to ensure the greatest compactness and absence of voids, which is especially important when burying bulky waste.
Compaction of waste during disposal is necessary not only to maximize the use of free space, but also to reduce the subsequent settling of the burial body. In addition, a loose burial body having a density below 0.6 t/m makes it difficult to control the leachate, since many channels inevitably appear in the body, making it difficult to collect and remove it.
However, sometimes, primarily for economic reasons, the storage is filled section by section. The main reasons for section filling are the need to separate various types waste within the same landfill, as well as the desire to reduce the area on which the leachate is formed.
When assessing the stability of a burial body, one should distinguish between external and internal stability. Internal stability is understood as the state of the burial body itself (stability of the sides, resistance to swelling); external stability is understood as the stability of the burial ground (subsidence, crushing). Lack of stability can damage the drainage system. The objects of control at landfills are air and biogas, ground water and leachate, soil and burial body. The scope of monitoring depends on the type of waste and the design of the landfill.
Requirements for landfills: prevention of impact on the quality of soil and surface water, on the quality of the air environment; prevention negative impact associated with the migration of pollutants into the underground space. In accordance with these requirements, it is necessary to provide: impermeable soil and waste covers, leakage control systems, maintenance and control of the landfill after closure, and other appropriate measures.
Basic elements of a safe landfill: a layer of surface soil with vegetation; drainage system along the edges of the landfill; an easily permeable layer of sand or gravel; an insulating layer of clay or plastic; waste in compartments; fine soil as the basis for an isolating word; ventilation system to remove methane and carbon dioxide; drainage layer for liquid drainage; lower insulating layer to prevent seepage of contaminants into groundwater.
Bibliography.
1. Eremkin A.I., Kvashnin I.M., Junkerov Yu.I. Rationing of emissions of pollutants into the atmosphere.: tutorial- M., ed. ASV, 2000 - 176 p.
2. Hygienic standards "Maximum Permissible Concentrations (MPC) of pollutants in the atmospheric air of populated areas" (GN2.1.6.1338-03), with Additions No. 1 (GN 2s.1.6.1765-03), Additions and changes No. 2 (GN 2.1.6.1983-05). Enacted by the Decrees of the Chief Sanitary Doctor of the Russian Federation No. 116 of May 30, 2003, No. 151 of October 17, 2003, No. 24 of November 3, 2005 (registered by the Ministry of Justice of Russia on June 9, 2003, reg. No. 4663; 10.21.2003 reg. No. 5187; 02.12.2005 reg. No. 7225)
3. Mazur I.I., Moldavanov O.I., Shishkov V.N. Engineering ecology, general course in 2 volumes. Under the general editorship. M.I. Masuria. - M.: graduate School, 1996. - v.2, 678 p.
4. Methodology for calculating the concentrations in the atmospheric air of harmful substances contained in the emissions of enterprises (OND-86). Decree of the USSR State Committee for Hydrometeorology dated 04.08.1986 No. 192.
5. CH 245-71. Sanitary norms for the design of industrial enterprises.
6. Uzhov V.I., Valdberg A.Yu., Myagkov B.I., Reshidov I.K. Purification of industrial gases from dust. -M.: Chemistry, 1981 - 302 p.
7. the federal law"On the Protection of Atmospheric Air" (as amended on December 31, 2005) dated May 4, 1999 No. 96-FZ
8. Federal Law "On Environmental Protection" dated 10.01.2002 No. 7-FZ (as amended on December 18, 2006)
9. Khudoshina M.Yu. Ecology. Laboratory workshop UMU GOU MSTU "STANKIN", 2005. Electronic version.
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