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MINISTRY OF EDUCATION AND SCIENCE OF RUSSIA

federal state budgetary educational institution higher vocational education

Ural State Forestry University

Department: physical and chemical technology of biosphere protection

Abstract on the topic:

« Theoretical basis environmental protection"

Performed:

Bakirova E. N.

Course: 3 Specialty: 241000

Teacher:

Melnik T.A.

Ekaterinburg 2014

Introduction

Chapter 1. Theoretical foundations of water basin protection

1.1 Basic theoretical principles of cleaning Wastewater from floating impurities

1.2 Basic requirements for the extractant

Chapter 2. Air protection from dust

2.1 Concept and definition of specific surface area of dust and flowability of dust

2.2 Purification of aerosols under the influence of inertial and centrifugal forces

2.3 Statics of the absorption process

Bibliography

Introduction

The development of civilization and modern scientific and technological progress are directly related to environmental management, i.e. With global use natural resources.

An integral part of environmental management is the processing and reproduction of natural resources, their protection, and the protection of the environment as a whole, which is carried out on the basis of engineering ecology - the science of the interaction of technical and natural systems.

Theoretical foundations of environmental protection is a comprehensive scientific and technical discipline of environmental engineering that studies the fundamentals of creating resource-saving, environmentally friendly technologies industrial productions, implementation of engineering and environmental solutions for rational environmental management and environmental protection.

The process of environmental protection is a process as a result of which pollution harmful to the environment and humans undergoes certain transformations into harmless ones, accompanied by the movement of pollution in space, a change in their aggregate state, internal structure and composition, and the level of their impact on the environment.

IN modern conditions environmental protection has become the most important problem, the solution of which is related to the protection of the health of current and future generations of people and all other living organisms.

Concern for the conservation of nature lies not only in the development and compliance with legislation on the protection of the Earth, its subsoil, forests and waters, atmospheric air, flora and fauna, but also in the knowledge of cause-and-effect relationships between various types of human activity and changes in the natural environment.

Changes in the environment are still outpacing the pace of development of methods for monitoring and predicting its condition.

Scientific research in the field of environmental engineering should be aimed at finding and developing effective methods and means of reducing the negative consequences of various types production activities human (anthropogenic) impact on the environment.

1. Theotheoretical principles of water basin protection

1.1 Basictheoretical principles of wastewater treatment from floating impurities

Separation of floating impurities: the settling process is also used to purify industrial wastewater from oil, oils, and fats. Cleaning from floating impurities is similar to settling solids. The difference is that the density of floating particles is less than the density of water.

Settling is the separation of a coarse liquid system (suspension, emulsion) into its constituent phases under the influence of gravity. During the settling process, particles (drops) of the dispersed phase precipitate from the liquid dispersion medium or float to the surface.

Settling as a technological technique is used to separate dispersed substances or purify liquids from mechanical impurities. The efficiency of settling increases with increasing difference in the densities of the separated phases and the particle size of the dispersed phase. When settling in the system, there should be no intense mixing, strong convection currents, or obvious signs of structure formation that prevent sedimentation.

Settling is a common method of purifying liquids from coarse mechanical impurities. It is used in the preparation of water for technological and household needs, sewage treatment, dehydration and desalting of crude oil, in many chemical technology processes.

It is important stage in the natural self-purification of natural and artificial reservoirs. Settling is also used to isolate various industrial or natural products dispersed in liquid media.

Settling, the slow separation of a liquid dispersed system (suspension, emulsion, foam) into its constituent phases: a dispersion medium and a dispersed substance (dispersed phase), occurring under the influence of gravity.

During the settling process, particles of the dispersed phase settle or float, accumulating, respectively, at the bottom of the vessel or at the surface of the liquid. (If settling is combined with decanting, then elutriation occurs.) The concentrated layer of individual droplets near the surface that appears during settling is called cream. Particles of suspension or drops of emulsion accumulated at the bottom form a sediment.

The accumulation of sediment or cream is determined by the laws of sedimentation (settling). The settling of highly dispersed systems is often accompanied by particle enlargement as a result of coagulation or flocculation.

The structure of the sediment depends on the physical characteristics of the dispersed system and settling conditions. It is dense when settling coarse systems. Polydisperse suspensions of finely ground lyophilic products give loose gel-like precipitates.

The accumulation of sediment (cream) during settling is due to the rate of settling (floating) of particles. In the simplest case of free motion of spherical particles, it is determined by Stokes' law. In polydisperse suspensions, large particles first precipitate, and small ones form a slowly settling “dregs”.

The difference in the settling rate of particles differing in size and density underlies the separation of crushed materials (rocks) into fractions (size classes) by hydraulic classification or elutriation. In concentrated suspensions, it is not free, but so-called. solidary, or collective, settling, in which quickly settling large particles carry small ones with them, brightening the upper layers of the liquid. If there is a colloidal dispersed fraction in the system, settling is usually accompanied by the enlargement of particles as a result of coagulation or flocculation.

The structure of the sediment depends on the properties of the dispersed system and settling conditions. Coarsely dispersed suspensions, the particles of which do not differ too much in size and composition, form a dense sediment clearly demarcated from the liquid phase. Polydisperse and multicomponent suspensions of finely ground materials, especially with anisometric (for example, lamellar, needle-shaped, thread-like) particles, on the contrary, give loose gel-like sediments. In this case, there may not be a sharp boundary between the clarified liquid and the sediment, but a gradual transition from less concentrated layers to more concentrated ones.

Recrystallization processes are possible in crystalline sediments. When settling aggregatively unstable emulsions, the droplets that accumulate at the surface in the form of cream or at the bottom coalesce (merge), forming a continuous liquid layer. IN industrial environment settling is carried out in settling basins (reservoirs, vats) and special settling tanks (thickeners) of various designs.

Sedimentation is widely used in water purification in systems of hydraulic structures, water supply, and sewerage; during dehydration and desalting of crude oil; in many chemical technology processes.

Sedimentation is also used for barn cleaning of drilling fluids; purification of liquid petroleum products (oils, fuels) in various machines and technological installations. Under natural conditions, sedimentation plays an important role in the self-purification of natural and artificial reservoirs, as well as in the geological processes of formation of sedimentary rocks.

Precipitation is the separation in the form of a solid precipitate from a gas (vapor), solution or melt of one or more components. To do this, conditions are created when the system goes from an initial stable state to an unstable one and a solid phase is formed in it. Deposition from vapor (desublimation) is achieved by lowering the temperature (for example, when iodine vapor is cooled, iodine crystals appear) or chemical transformations of vapor, which are caused by heating, exposure to radiation, etc. Thus, when white phosphorus vapor is overheated, a precipitate of red phosphorus is formed; When vapors of volatile metal -diketonates are heated in the presence of O2, films of solid metal oxides are deposited.

Precipitation of the solid phase from solutions can be achieved different ways: lowering the temperature of a saturated solution, removing the solvent by evaporation (often in vacuum), changing the acidity of the medium, the composition of the solvent, for example, adding a less polar one (acetone or ethanol) to a polar solvent (water). The latter process is often referred to as salting out.

Various chemical precipitating reagents are widely used for precipitation, interacting with the released elements to form poorly soluble compounds that precipitate. For example, when a BaCl2 solution is added to a solution containing sulfur in the form of SO2-4, a precipitate of BaSO4 is formed. To separate precipitates from melts, the latter are usually cooled.

The work of crystal nucleation in a homogeneous system is quite large, and the formation of the solid phase is facilitated on the finished surface of the solid particles.

Therefore, to accelerate deposition, a seed - highly dispersed solid particles of the deposited or other substance - is often introduced into supersaturated steam and solution or into a supercooled melt. The use of seeds in viscous solutions is especially effective. The formation of sediment can be accompanied by coprecipitation - partial capture of cells. solution component.

After precipitation from aqueous solutions The resulting highly dispersed precipitate is often given the opportunity to “mature” before separation, i.e. keep the precipitate in the same (mother) solution, sometimes with heating. In this case, as a result of the so-called Ostwald ripening, caused by the difference in solubility of small and large particles, aggregation and other processes, sediment particles become larger, coprecipitated impurities are removed, and filterability improves. The properties of the resulting precipitates can be changed over a wide range due to the introduction of various additives (surfactants, etc.) into the solution, changes in temperature or stirring speed, and other factors. Thus, by varying the conditions for the precipitation of BaSO4 from aqueous solutions, it is possible to increase the specific surface area of the sediment from ~0.1 to ~ 10 m2/g or more, change the morphology of the sediment particles, and modify the surface properties of the latter. The resulting sediment usually settles to the bottom of the vessel under the influence of gravity. If the precipitate is fine, centrifugation is used to facilitate its separation from the mother liquor.

Various types of precipitation are widely used in chemistry in the detection chemical elements by characteristic sediment and in the quantitative determination of substances, to remove components that interfere with the determination and to isolate impurities by co-precipitation, when purifying salts by recrystallization, to obtain films, as well as in chemical applications. industry for phase separation.

In the latter case, sedimentation refers to the mechanical separation of suspended particles from a liquid in suspension under the influence of gravity. These processes are also called sedimentation. sedimentation, sedimentation, thickening (if sedimentation is carried out to obtain a dense sediment) or clarification (if pure liquids are obtained). For thickening and clarification, filtration is often additionally used.

A necessary condition for deposition is the existence of a difference in the densities of the dispersed phase and the dispersion medium, i.e. sedimentation instability (for coarse systems). For highly dispersed systems, a sedimentation criterion has been developed, which is determined mainly by entropy, as well as temperature and other factors. It has been established that entropy is higher when deposition occurs in a flow rather than in a stationary liquid. If the sedimentation criterion is less than a critical value, sedimentation does not occur and sedimentation equilibrium is established, in which dispersed particles are distributed along the height of the layer according to a certain law. During the sedimentation of concentrated suspensions, large particles, when falling, entrain smaller ones, which leads to the enlargement of sediment particles (orthokinetic coagulation).

The deposition rate depends on the physical properties of dispersed and dispersed phases, dispersed phase concentration, temperature. The settling speed of an individual spherical particle is described by the Stokes equation:

where d is the diameter of the particle, ?g is the difference in densities of the solid (with s) and liquid (with f) phases, µ is the dynamic viscosity of the liquid phase, g is the acceleration of gravity. The Stokes equation is applicable only to the strictly laminar mode of particle motion, when the Reynolds number Re<1,6, и не учитывает ортокинетическую коагуляцию, поверхностные явления, влияние изменения концентрации твердой фазы, роль стенок сосуда и др. факторы.

The sedimentation of monodisperse systems is characterized by the hydraulic particle size, which is numerically equal to the experimentally determined rate of their sedimentation. In the case of polydisperse systems, the root-mean-square radius of the particles or their average hydraulic size is used, which is also determined experimentally.

During sedimentation under the influence of gravity in the chamber, three zones with different sedimentation rates are distinguished: in the zone of free fall of particles it is constant, then in the transition zone it decreases and, finally, in the compaction zone it sharply drops to zero.

In the case of polydisperse suspensions at low concentrations, sediments are formed in the form of layers - in the bottom layer the largest particles are, and then smaller ones. This phenomenon is used in elutriation processes, i.e., classification (separation) of solid dispersed particles according to their density or size, for which the sediment is mixed several times with a dispersion medium and left for various periods of time.

The type of precipitate formed is determined by the physical characteristics of the dispersed system and the deposition conditions. In the case of coarsely dispersed systems, the sediment is dense. Loose gel-like precipitates are formed during the precipitation of polydisperse suspensions of finely ground lyophilic substances. “Consolidation” of sediments in some cases is associated with the cessation of Brownian motion of particles of the dispersed phase, which is accompanied by the formation of a spatial structure of sediment with the participation of a dispersion medium and a change in entropy. In this case, the shape of the particles plays an important role. Sometimes, to speed up sedimentation, flocculants are added to the suspension - special substances (usually high molecular weight) that cause the formation of flaky flocculent particles.

1.2 Basic requirements for the extractant

Extraction methods of purification. To isolate organic substances dissolved in them, for example, phenols and fatty acids, from industrial wastewater, you can use the ability of these substances to dissolve in some other liquid that is insoluble in the water being treated. If such a liquid is added to the wastewater being treated and mixed, then these substances will dissolve in the added liquid, and their concentration in the wastewater will decrease. This physicochemical process is based on the fact that when two mutually insoluble liquids are thoroughly mixed, any substance in solution is distributed between them in accordance with its solubility according to the distribution law. If, after this, the added liquid is separated from the wastewater, then the latter turns out to be partially cleared of dissolved substances.

This method of removing solutes from wastewater is called liquid-liquid extraction; the dissolved substances removed in this case are the extractable substances, and the added liquid that does not mix with wastewater is the extractant. Butyl acetate, isobutyl acetate, diisopropyl ether, benzene, etc. are used as extractants.

There are a number of other requirements for the extractant:

· It should not form emulsions with water, as this leads to a decrease in the productivity of the installation and an increase in solvent losses;

· must be easily regenerated;

· be non-toxic;

· dissolve the extracted substance much better than water, i.e. have a high distribution coefficient;

· have high dissolution selectivity, i.e. the less the extractant dissolves the components that should remain in the wastewater, the more completely the substances that need to be removed will be extracted;

· have the greatest possible dissolving ability in relation to the extracted component, since the higher it is, the less extractant is required;

· have low solubility in wastewater and do not form stable emulsions, since the separation of the extract and raffinate is difficult;

· differ significantly in density from waste water to ensure rapid and complete phase separation;

Extractants can be divided into two groups according to their dissolving ability. Some of them can extract predominantly only one impurity or impurities of only one class, while others can extract most of the impurities of a given wastewater (in the extreme case, all). The first type of extractants is called selective.

The extractive properties of a solvent can be enhanced by exploiting the synergistic effect found in mixed solvent extraction. For example, when extracting phenol from wastewater, there is an improvement in extraction with butyl acetate mixed with butyl alcohol.

The extraction method for the purification of industrial wastewater is based on the dissolution of the pollutant found in the wastewater with organic solvents - extractants, i.e. on the distribution of a pollutant in a mixture of two mutually insoluble liquids according to its solubility in them. The ratio of mutually equilibrating concentrations in two immiscible (or weakly miscible) solvents when equilibrium is reached is constant and is called the distribution coefficient:

k p = C E + C ST?const

where C e, C st is the concentration of the extracted substance in the extractant and waste water, respectively, at steady state equilibrium, kg/m 3 .

This expression is the law of equilibrium distribution and characterizes the dynamic equilibrium between the concentrations of the extracted substance in the extractant and water at a given temperature.

The distribution coefficient kp depends on the temperature at which the extraction is carried out, as well as on the presence of various impurities in the wastewater and extractant.

After reaching equilibrium, the concentration of the extracted substance in the extractant is significantly higher than in the branch water. The substance concentrated in the extractant is separated from the solvent and can be disposed of. The extractant is then used again in the purification process.

2. Air protection from dust

2.1 Concept and definition of specific surface area of dust and flowability of dust

Specific surface area is the ratio of the surface area of all particles to the occupied mass or volume.

Flowability characterizes the mobility of dust particles relative to each other and their ability to move under the influence of external force. Flowability depends on the size of the particles, their moisture content and the degree of compaction. Flowability characteristics are used to determine the angle of inclination of the walls of bunkers, chutes and other devices associated with the accumulation and movement of dust and dust-like materials.

The flowability of dust is determined by the angle of repose of the natural slope, which receives dust in a freshly poured state.

b= arctan(2H/D)

2.2 Purification of aerosols under the influence of inertial and centrifugal forces

Devices in which the separation of particles from a gas flow occurs as a result of twisting the gas into a spiral are called cyclones. Cyclones capture particles up to 5 microns. Gas supply speed is at least 15 m/s.

R c =m*? 2 /R avg;

R av =R 2 +R 1 /2;

The parameter that determines the efficiency of the apparatus is the separation factor, which shows how many times the centrifugal force is greater than Fm.

F c = P c /F m = m*? 2 / R av *m*g= ? 2 / R av *g

Inertial dust collectors: The operation of an inertial dust collector is based on the fact that when the direction of movement of the flow of dusty air (gas) changes, dust particles, under the influence of inertial forces, deviate from the flow line and are separated from the flow. Inertial dust collectors include a number of well-known devices: dust separator IP, louvered dust collector VTI, etc., as well as the simplest inertial dust collectors (dust bag, dust collector on a straight section of the gas duct, screen dust collector, etc.).

Inertial dust collectors catch coarse dust - 20 - 30 microns in size or more, their efficiency is usually in the range of 60 - 95%. The exact value depends on many factors: dust dispersion and its other properties, flow speed, apparatus design, etc. For this reason, inertial apparatuses are usually used at the first stage of cleaning, followed by dust removal of gas (air) in more advanced apparatuses. The advantage of all inertial dust collectors is the simplicity of the device and the low cost of the device. This explains their prevalence.

F iner =m*g+g/3

2.3 Statics of the absorption process

Absorption of gases (lat. Absorptio, from absorbeo - absorb), volumetric absorption of gases and vapors by a liquid (absorbent) with the formation of a solution. The use of absorption in technology for the separation and purification of gases and the separation of vapors from vapor-gas mixtures is based on the difference in solubility of gases and vapors in liquids.

During absorption, the gas content in the solution depends on the properties of the gas and liquid, on the total pressure, temperature and partial pressure of the distributed component.

The statics of absorption, i.e., the equilibrium between the liquid and gas phases, determines the state that is established during very long contact of the phases. The equilibrium between the phases is determined by the thermodynamic properties of the component and absorber and depends on the composition of one of the phases, temperature and pressure.

For the case of a binary gas mixture consisting of distributed component A and carrier gas B, two phases and three components interact. Therefore, according to the phase rule, the number of degrees of freedom will be equal to

S=K-F+2=3-2+2=3

This means that for a given gas-liquid system the variables are temperature, pressure and concentrations in both phases.

Consequently, at constant temperature and total pressure, the relationship between concentrations in the liquid and gas phases will be unambiguous. This dependence is expressed by Henry's law: the partial pressure of a gas above a solution is proportional to the mole fraction of this gas in the solution.

The numerical values of the Henry coefficient for a given gas depend on the nature of the gas and absorber and on temperature, but do not depend on the total pressure. An important condition determining the choice of absorbent is the favorable distribution of gaseous components between the gas and liquid phases at equilibrium.

The interphase distribution of components depends on the physicochemical properties of the phases and components, as well as on temperature, pressure and the initial concentration of the components. All components present in the gas phase form a gas solution in which there is only weak interaction between the molecules of the component. A gas solution is characterized by chaotic movement of molecules and the absence of a specific structure.

Therefore, at ordinary pressures, a gas solution should be considered as a physical mixture in which each component exhibits its own individual physical and chemical properties. The total pressure exerted by a gas mixture is the sum of the pressures of the components of the mixture, called partial pressures.

The content of components in a gaseous mixture is often expressed in terms of partial pressures. Partial pressure is the pressure under which a given component would be if, in the absence of other components, it occupied the entire volume of the mixture at its temperature. According to Dalton's law, the partial pressure of a component is proportional to the mole fraction of the component in the gas mixture:

where y i is the mole fraction of the component in the gas mixture; P is the total pressure of the gas mixture. In a two-phase gas-liquid system, the partial pressure of each component is a function of its solubility in the liquid.

According to Raoult's law for an ideal system, the partial pressure of a component (pi) in a vapor-gas mixture above a liquid under equilibrium conditions, with low concentration and non-volatility of other components dissolved in it, is proportional to the vapor pressure of the pure liquid:

p i =P 0 i *x i ,

where P 0 i is the saturated vapor pressure of the pure component; x i is the mole fraction of the component in the liquid. For nonideal systems, positive (pi / P 0 i > xi) or negative (pi / P 0 i< x i) отклонение от закона Рауля.

These deviations are explained, on the one hand, by the energy interaction between the molecules of the solvent and the dissolved substance (change in the enthalpy of the system - ?H), and on the other hand, by the fact that the entropy (?S) of mixing is not equal to the entropy of mixing for an ideal system, since during the formation solution, the molecules of one component acquired the ability to be located among the molecules of another component a large number ways than among similar ones (entropy has increased, a negative deviation is observed).

Raoult's law applies to solutions of gases, critical temperature which are higher than the temperature of the solution and which are capable of condensing at the temperature of the solution. At temperatures below critical, Henry's law applies, according to which the equilibrium partial pressure (or equilibrium concentration) of a substance dissolved above a liquid absorber at a certain temperature and in the range of its low concentration, for non-ideal systems, is proportional to the concentration of the component in the liquid x i:

where m is the distribution coefficient of the i-th component at phase equilibrium, depending on the properties of the component, absorber and temperature (Henry’s isothermal constant).

For most systems, the water - gaseous component coefficient m can be found in the reference literature.

For most gases, Henry's law is applicable at a total pressure in the system of no more than 105 Pa. If the partial pressure is greater than 105 Pa, the m value can only be used in a narrow range of partial pressures.

When the total pressure in the system does not exceed 105 Pa, the solubility of gases does not depend on the total pressure in the system and is determined by Henry's constant and temperature. The effect of temperature on the solubility of gases is determined from the expression:

purification absorption extraction precipitation

where C is the differential heat of dissolution of one mole of gas in an infinitely large amount of solution, defined as the magnitude of the thermal effect (H i - H i 0) of the transition of the i-th component from gas to solution.

In addition to the noted cases, in engineering practice there is a significant number of systems for which the equilibrium interphase distribution of a component is described using special empirical dependencies. This applies in particular to systems containing two or more components.

Basic conditions of the absorption process. Each of the components of the system creates a pressure, the magnitude of which is determined by the concentration of the component and its volatility.

When the system remains in constant conditions for a long time, an equilibrium distribution of components between the phases is established. The absorption process can occur provided that the concentration (partial pressure of the component) in the gas phase that comes into contact with the liquid is higher than the equilibrium pressure above the absorption solution.

Bibliography

1. Vetoshkin A.G. Theoretical foundations of environmental protection: tutorial. - Penza: PGASA Publishing House, 2002. 290 p.

2. Engineering protection of surface waters from industrial wastewater: textbook. allowance D.A. Krivoshein, P.P. Kukin, V.L. Lapin [and others]. M.: Higher School, 2003. 344 p.

4. Fundamentals of chemical technology: a textbook for students of chemical and technical universities / I.P. Mukhlenov, A.E. Gorshtein, E.S. Tumarkin [Ed. I.P. Mukhlenova]. 4th ed., revised. and additional M.: Higher. school, 1991. 463 p.

5. Dikar V.L., Deineka A.G., Mikhailiv I.D. Fundamentals of ecology and environmental management. Kharkov: Olant LLC, 2002. 384 p.

6. Ramm V.M./ Absorption of gases, 2nd ed., M.: Chemistry, 1976.656 p.

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...

Dean of the Faculty

aircraft

“___”______________200 g.

WORK PROGRAM of the academic discipline

theoretical foundations of environmental protection

OOP in the direction of training a certified specialist

656600 – Environmental protection

specialty 280202 “Engineering environmental protection”

Qualification – environmental engineer

Faculty of Aircraft

Course 3, semester 6

Lectures 34 hours.

Practical classes: 17 hours.

RGZ 6th semester

Independent work 34 hours

Exam 6 semester

Total: 85 hours

Novosibirsk

The work program is drawn up on the basis of the State educational standard higher professional education in the direction of training a certified specialist – 656600 - Environmental protection and specialty 280202 – “Engineering environmental protection”

Registration number 165 technical/ds dated March 17, 2000.

Discipline code in the State Educational Standards – SD.01

The discipline “Theoretical Foundations of Environmental Protection” belongs to the federal component.

Discipline code according to the curriculum - 4005

The work program was discussed at a meeting of the Department of Environmental Engineering Problems.

Minutes of the department meeting No. 6-06 dated October 13, 2006

The program was developed

professor, doctor of technical sciences, professor

Head of the department

Professor, Doctor of Technical Sciences, Associate Professor

Responsible for the main

professor, doctor of technical sciences, professor

1. External requirements

General requirements for education are given in Table 1.

Table 1

State Standards requirements for mandatory minimum

disciplines

"Theoretical foundations of environmental protection"

Theoretical foundations of environmental protection: physical and chemical foundations of wastewater and waste gas treatment processes and solid waste disposal. Processes of coagulation, flocculation, flotation, adsorption, liquid extraction, ion exchange, electrochemical oxidation and reduction, electrocoagulation and electroflotation, electrodialysis, membrane processes (reverse osmosis, ultrafiltration), precipitation, deodorization and degassing, catalysis, condensation, pyrolysis, remelting, roasting , fire neutralization, high-temperature agglomeration.

Theoretical foundations of environmental protection from energy impacts. The principle of screening, absorption and suppression at the source. Diffusion processes in the atmosphere and hydrosphere. Dispersion and dilution of impurities in the atmosphere and hydrosphere. Dispersion and dilution of impurities in the atmosphere and hydrosphere. Calculation and dilution methods.

2. Goals and objectives of the course

The main goal is to familiarize students with the physical and chemical principles of neutralizing toxic anthropogenic waste and mastering the initial skills of engineering methods for calculating equipment for neutralizing this waste.

3. Requirements for discipline

The basic requirements for the course are determined by the provisions of the State Educational Standard (SES) in the direction 553500 - environmental protection. In accordance with the State Standards for the specified direction in work program The following main sections are included:

Section 1. Main environmental pollutants and methods of their neutralization.

Section 2. Fundamentals of calculation of adsorption, mass transfer and catalytic processes.

4. Scope and content of the discipline

The scope of the discipline corresponds to the curriculum approved by the Vice-Rector of NSTU

The name of the topics of lecture classes, their content and volume in hours.

Section 1. Main environmental pollutants and methods of their neutralization (18 hours).

Lecture 1. Anthropogenic pollutants of industrial centers. Water, air and soil pollutants. Formation of nitrogen oxides in combustion processes.

Lecture 2. Basics of calculating the dispersion of impurities in the atmosphere. Coefficients used in contaminant dispersion models. Examples of impurity dispersion calculations.

Lectures 3-4. Methods for cleaning industrial gas emissions. Concept of purification methods: absorption, adsorption, condensation, membrane, thermal, chemical, biochemical and catalytic methods for neutralizing pollutants. Areas of their application. Basic technological features and process parameters.

Lecture 5. Wastewater treatment based on separation methods. Purification of wastewater from mechanical impurities: settling tanks, hydrocyclones, filters, centrifuges. Physico-chemical basis for the use of flotation, coagulation, flocculation to remove impurities. Methods for intensifying wastewater treatment processes from mechanical impurities.

Lecture 6. Regenerative methods of wastewater treatment. The concept and physicochemical basis of the methods of extraction, stripping (desorption), distillation and rectification, concentration and ion exchange. Use of reverse osmosis, ultrafiltration and adsorption for water purification.

Lectures 7-8. Destructive methods of water purification. The concept of destructive methods. Use for water purification chemical methods, based on the neutralization of acidic and alkaline pollutants, reduction and oxidation (chlorination and ozonation) of impurities. Purification of water by converting pollutants into insoluble compounds (formation of sediments). Biochemical wastewater treatment. Features and mechanism of the cleaning process. Aerotanks and digesters.

Lecture 9. Thermal method neutralization of wastewater and solid waste. Technological diagram of the process and types of equipment used. The concept of fire neutralization and pyrolysis of waste. Liquid-phase oxidation of waste – concept of the process. Features of activated sludge processing.

Section 2 Fundamentals of calculating adsorption, mass transfer and catalytic processes (16 hours).

Lecture 10. Main types of catalytic and adsorption reactors. Shelf, tube and fluidized bed reactors. Areas of their application for neutralization of gas emissions. Designs of adsorption reactors. Use of moving layers of adsorbent.

Lecture 11. Fundamentals of calculations for gas emissions neutralization reactors. The concept of reaction speed. Hydrodynamics of stationary and fluidized granular layers. Idealized reactor models - ideal mixing and ideal displacement. Derivation of material and heat balance equations for ideal mixing and ideal displacement reactors.

Lecture 12. Processes on porous adsorbent and catalyst granules. The stages of the process of chemical (catalytic) transformation on a porous particle. Diffusion in a porous particle. Molecular and Knudsen diffusion. Derivation of the material balance equation for a porous particle. Concept of degree of use inner surface porous particles.

Lectures 13-14. Fundamentals of adsorption processes. Adsorption isotherms. Methods for experimental determination of adsorption isotherms (weight, volume and chromatographic methods). Langmuir adsorption equation. Mass and heat balance equations for adsorption processes. Stationary sorption front. The concept of equilibrium and nonequilibrium adsorption. Examples of practical application and calculation of the adsorption process for purifying gases from benzene vapors.

Lecture 15. The mechanism of mass transfer processes. Mass transfer equation. Equilibrium in the liquid-gas system. Henry and Dalton equations. Schemes of adsorption processes. Material balance of mass transfer processes. Derivation of the process operating line equation. Driving force mass transfer processes. Determination of average driving force. Types of adsorption devices. Calculation of adsorption apparatuses.

Lecture 16. Purification of exhaust gases from mechanical pollutants. Mechanical cyclones. Calculation of cyclones. Selection of cyclone types. Calculation determination of dust collection efficiency.

Lecture 17. Basics of gas purification using electric precipitators. Physical foundations trapping mechanical impurities with electric precipitators. Calculation equations for assessing the efficiency of electric precipitators. Basics of designing electrostatic precipitators. Methods for increasing the efficiency of trapping mechanical particles by electric precipitators.

Total hours (lectures) – 34 hours.

The name of the topics of practical classes, their content and volume in hours.

1. Methods for cleaning gas emissions from toxic compounds (8 hours), including:

a) catalytic methods (4 hours);

b) adsorption methods (2 hours);

c) gas purification using cyclones (2 hours).

2. Basics of calculating reactors for gas neutralization (9 hours):

a) calculation of catalytic reactors based on ideal mixing and ideal displacement models (4 hours);

b) calculation of adsorption devices for gas purification (3 hours);

c) calculation of electric precipitators to capture mechanical pollutants (2 hours).

________________________________________________________________

Total hours (practical classes) – 17 hours

Name of topics for calculation and graphic tasks

1) Determination of the hydraulic resistance of the fixed granular layer of the catalyst (1 hour).

2) Study of fluidization regimes for granular materials (1 hour).

3) Study of the process of thermal neutralization of solid waste in a fluidized bed reactor (2 hours).

4) Determination of the adsorption capacity of sorbents to capture gaseous pollutants (2 hours).

________________________________________________________________

Total (calculation and graphic tasks) – 6 hours.

4. Forms of control

4.1. Protection of calculation and graphic tasks.

4.2. Defense of abstracts on course topics.

4.3. Questions for the exam.

1. Fundamentals of absorption processes for gas purification. Types of absorbers. Basics of calculation of absorbers.

2. Designs of catalytic reactors. Tubular, adiabatic, with a fluidized bed, with radial and axial gas flow, with moving layers.

3. Distribution of emissions from pollution sources.

4. Adsorption processes for gas purification. Technological schemes of adsorption processes.

5. Wastewater treatment by oxidizing impurities with chemical reagents (chlorination, ozonation).

6. Diffusion in a porous granule. Molecular and Knudsen diffusion.

7. Conditioning methods of gas purification.

8. Thermal disposal of solid waste. Types of decontamination furnaces.

9. Equation of an ideal mixing reactor.

10. Membrane methods for gas purification.

11. Hydrodynamics of fluidized granular beds.

12. Fluidization conditions.

13. Basics of aerosol capture by electric precipitators. Factors influencing the effectiveness of their work.

14. Thermal neutralization of gases. Thermal neutralization of gases with heat recovery. Types of thermal decontamination furnaces.

15. Fundamentals of extraction wastewater treatment processes.

16. Model of a plug-flow reactor.

17. Fundamentals of chemical methods of gas purification (irradiation of electron flows, ozonation)

18. Hydrodynamics of stationary granular layers.

19. Equilibrium in the “liquid - gas” system.

20. Biochemical gas purification. Biofilters and bioscrubers.

21. Biochemical purification - the basics of the process. Aerotanks, metatanks.

22. Idealized models of catalytic reactors. Material and heat balances.

23. Types of wastewater pollutants. Classification of cleaning methods (separation, regenerative and destructive methods).

24. Adsorption front. Equilibrium adsorption. Stationary adsorption front.

25. Dust collection equipment- cyclones. Cyclone calculation sequence.

26. Methods for separating mechanical impurities: settling tanks, hydrocyclones, filters, centrifuges).

27. Concentration - as a method of wastewater treatment.

28. Adsorption front. Equilibrium adsorption. Stationary adsorption front.

29. Fundamentals of flotation, coagulation, flocculation.

30. Heat (mass) exchange during adsorption.

31. Sequence of calculation of a packed absorber.

32. Physical principles of intensification of wastewater treatment processes (magnetic, ultrasonic methods).

33. Transformation processes on a porous particle.

34. Sequence of calculations of adsorbers.

35. Desorption is a method of removing volatile impurities from wastewater.

36. Adsorption wastewater treatment.

37. The concept of the degree of utilization for catalyst particles.

38. Distribution of emissions from pollution sources.

39. Distillation and rectification in wastewater treatment.

40. Nonequilibrium adsorption.

41. Reverse osmosis and ultrafiltration.

42. Adsorption isotherms. Methods for determining adsorption isotherms (weight, volume, chromatography).

43. Fundamentals of liquid-phase oxidation of wastewater under pressure.

44. Driving force of mass transfer processes.

45. Wastewater treatment by neutralization, recovery, sedimentation.

46. Thermal and thermal equations material balance adsorber.

47. Dust collection equipment - cyclones. Cyclone calculation sequence.

48. Biochemical purification - the basics of the process. Aerotanks, metatanks.

49. Basics of aerosol capture by electric precipitators. Factors influencing the effectiveness of their work.

1. Equipment, structures, fundamentals of designing chemical and technological processes, protecting the biosphere from industrial emissions. M., Chemistry, 1985. 352 p.

2. . . Maximum permissible concentrations of chemicals in the environment. L. Chemistry, 1985.

3. B. Bretschneider, I. Kurfurst. Protection of the air basin from pollution. L. Chemistry, 1989.

4. . Neutralization of industrial emissions by afterburning. M. Energoatomizdat, 1986.

5., etc. Industrial wastewater treatment. M. Stroyizdat, 1970, 153 p.

6., etc. Industrial wastewater treatment. Kyiv, Tekhnika, 1974, 257 p.

7. . . Wastewater treatment in the chemical industry. L, Chemistry, 1977, 464 p.

8. AL. Titov, . Disposal of industrial waste: M. Stroyizdat, 1980, 79 p.

9. , . The impact of thermal power plants on the environment and ways to reduce the damage caused. Novosibirsk, 1990, 184 p.

10. . Theoretical foundations of environmental protection (lecture notes). IC SB RAS - NSTU, 2001. – 97s.

Humans have had an impact on the environment since ancient times. The constant economic development of the world improves human life and expands its natural habitat, 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 twentieth century that the scientific basis for this impact, as well as the problems that arose as a result, arose, and the development 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.

The term “ecology” was first used by the biologist E. Haeckel: “By ecology we mean the general science of the relationship between the organism and the environment, where we include all the “conditions of existence” in the broad sense of the 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 classic definition of ecology: a science that studies the relationships between living and inanimate nature. http://www.werkenzonderdiploma.tk/news/nablyudaemomu-v-nastoyaschee-83.html

Two alternative definitions of this science:

· Ecology is the knowledge of the economy of nature, the simultaneous study of all relationships between living things and organic and inorganic components of the environment... In a word, ecology is a science that studies all the complex relationships in nature, considered by Darwin as conditions of the struggle for existence.

· Ecology is a biological science that studies the structure and functioning of systems at the supraorganism level (populations, communities, ecosystems) in space and time, in natural and human-modified conditions.

Ecology in scientific papers logically moved into the concept of sustainable development.

Sustainable development - environmental development - involves meeting the needs and aspirations of the present without compromising the ability of future generations to meet their needs. Transition to the era of sustainable development., R.A. Flight, p. 10-31 // Russia in the world around us: 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 concern over environmental issues has increased over the past decades, concern for the fate of future generations and the 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 now a global need for at least three reasons. The main reason is that all species have the right to live in the conditions that are characteristic of them. Second, multiple life forms maintain chemical and physical balance on Earth. Finally, experience shows that maintaining a maximum genetic pool is of economic interest to Agriculture and 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 increasingly acute. Future generations will no longer have the natural resource reserves that previous generations had.

To solve a number of environmental problems, the European Union uses energy-saving technology; in the United States, the emphasis is on bioengineering. However, developing countries and countries with economies in transition have not realized the importance of environmental impact. Often the solution to problems in these countries occurs under the influence of external forces, and not public policy. This attitude could lead to an even greater widening of the gap between developed and developing countries, and, just as importantly, to increased environmental degradation.

To summarize, it should be noted that with economic development With the development of new technologies, the state of the environment is also changing, and the threat of environmental degradation is increasing. At the same time, new technologies are being created to solve environmental problems.