Waste incineration of municipal solid waste. Ecofan - waste incineration with heat generation for heating

In world practice, to date, the overwhelming amount of solid waste is still being taken to landfills (landfills). The most rational method of MSW processing is incineration. Its origin dates back to 1870. Its main advantage is the reduction of waste volumes by more than 10 times, and their mass - by 3 times. The main disadvantage of direct incineration of untreated MSW is associated with a serious risk of atmospheric pollution with harmful emissions. Waste incineration is the most complex and “high-tech” option for waste management. Incineration requires pre-treatment of MSW (with the production of so-called fuel extracted from waste). When separating from MSW, they try to remove large objects, metals (both magnetic and non-magnetic) and further crush it. In order to reduce harmful emissions, batteries and accumulators, plastic, and leaves are also removed from the waste. The incineration of an undivided waste stream is now considered extremely dangerous. Thus, waste incineration can only be one component of a comprehensive recycling program. Advantages of this method:

Reducing the volume of waste by 10 times;

Reducing the risk of soil and water pollution by waste;

Possibility of heat recovery.

Disadvantages of waste incineration of initial MSW:

the danger of air pollution;

destruction of valuable components;

high yield of ash and slag (about 30% by weight);

· low efficiency of recovery of ferrous metals from slags;

Difficulty in stabilizing the combustion process.

60.Solid waste incineration

The combustion of solid and pasty wastes can be carried out in all types of furnaces, with the exception of sparging and turbo sparging. The most widely used are torch-layer furnaces. The stratified combustion furnaces, which are used more than others for burning solid waste (primarily municipal solid waste and its mixture with industrial waste), are classified according to a number of other criteria: methods of feeding and igniting waste, removing slag, etc. According to the mode of supply of waste to the layer, combustion devices with periodic and continuous loading are distinguished. According to the organization of thermal preparation and ignition of waste in the layer, furnaces with lower, upper and mixed (unlimited) ignition are distinguished. According to the method of supplying fuel (waste) to the layer, there are the following schemes, which differ in the combination of directions of gas-air and fuel-slag flows: oncoming (counter-flow), parallel (forward flow), transverse (cross-current) and mixed. Numerous studies of the burning fuel layer (using zonometry, above-layer gas analysis, gas formation in the layer, temperature distribution in the layer) made it possible to conditionally divide the entire process in it into three main periods: preparation of fuel (waste) for combustion, combustion itself (oxidation and reduction zones) , afterburning of combustible and focal residues. In the preparation zone, the waste is heated, moisture is removed from it and volatile substances formed as a result of heating the waste are released. In the oxygen zone, the carbon of the coke is burned to form carbon dioxide and partially carbon monoxide, as a result of which the main amount of heat is released in the layer. At the end of the oxygen zone, the maximum CO2 concentration and layer temperature are observed. Directly adjacent to the oxygen zone is the reduction zone, in which the reduction of carbon dioxide, carbon monoxide occurs with the consumption of a known amount of heat. The combustion process ends with the burning of ashed coke. Layered furnaces are widely used for burning solid domestic and similar in morphological composition of fire.

Drum kilns- the main type of heat and power equipment, which is used for centralized combustion of solid and pasty waste. These furnaces are equipped with waste disposal stations. The main unit of the drum furnace (Fig. 3.12) is a horizontal cylindrical body 1, covered with a refractory lining 2 and supported by bandages 6 on rollers 7. The drum is inclined at a slight angle towards the slag discharge and during operation rotates at a speed of 0.8 ... 2 min- 1, receiving movement from the drive 10 through the ring gear 9. To avoid longitudinal displacement of the drum, rollers 8 are provided.

Scheme of a drum furnace: A - waste loading; B - unloading of ash (slag); C - flue gases; D - additional fuel; E - air; F - thermal radiation; 1 - body of a drum furnace; 2 - lining; 3 - unloading end; 4 - connecting segments; 5 - fan; 6 - bandages; 7 - support rollers; 8 - side rollers; 9 - ring gear; 10 - drive; 11 - water evaporation zone; 12 - waste; 13 - combustion zone; 14 - ash (slag).

Solid and pasty wastes are fed into the furnace body from its end in the direction of arrows A. If necessary, additional fuel or liquid combustible wastes (solvents) are sprayed through the nozzle (arrow D), raising the temperature inside the furnace. In zone 12, the incoming material, being mixed during the rotation of the furnace, is dried, partially gasified and moved to the combustion zone 13. Radiation from the flame in this zone heats the furnace lining and contributes to the burning out of the organic part of the waste and drying of the newly received material. The slag formed in zone 24 moves to the opposite end of the furnace in the direction of arrow B, where it falls into a device for wet or dry ash and slag quenching.

Products of human activities in everyday life, transport, in the fields of industry and economy, which do not find application directly in the places of their formation, or are used as raw materials in other areas of industry or during processing, are called waste. They can be the remains of materials, raw materials, residual semi-finished products that are formed during the production process and lose their useful physical qualities (in whole or in part). During the processing of raw materials, during the extraction, enrichment of minerals, products are also formed that are considered production waste, because this production is not engaged in obtaining these products. Unsuitable for further use for its intended purpose, decommissioned cars, various tools, household products are called consumer waste.

The possible use of waste defines it as recyclable and non-recyclable. With regard to recyclable waste, there are all kinds of technologies for their processing, accompanied by their involvement in the turnover of the economy or industry. For non-recyclable waste, such technologies do not currently exist. The classifier of industrial waste, the calculation of the hygienic values ​​of the substance or the experimental way determine the belonging of the waste to certain groups.

Wastes of all groups and classes are divided into:

• solid waste,
• paste-like,
• liquid,
• pulverized (gaseous).

Waste of the solid group includes unusable containers (metal, wood, cardboard, plastic), cleaning materials, used filter elements and filter materials, trimmings of polymer pipes, cable products residues. Waste of the pasty group includes sludge, resin, filter cakes and cakes from filters and sedimentation tanks after cleaning tanks from heat exchangers. Liquid waste can be sewage, which, due to its high toxicity, is not subject to biological treatment. Dust-like (gaseous) wastes are emissions from degreasing sites in metallurgical production, when painting equipment.

The belonging of waste to a chemical resistance group divides them into explosive, spontaneously igniting, decomposing (with the release of toxic gases), and stable. Waste is further divided into water-soluble waste and water-insoluble waste. Based on their origin, wastes are divided into organic, inorganic and mixed wastes. Industrial wastes are often chemical wastes, which are heterogeneous, complex mixtures of polycomponents that have all kinds of physical and chemical properties and may present chemical, toxic, corrosive, biological, fire and explosion hazards. Waste can be classified according to various characteristics: according to their chemical characteristics, according to their technological formation, according to their possible processing in the future and their further use. In Russia chemical wastes are divided into four hazard classes associated with the costs of their processing and disposal:

1. waste is extremely hazardous class; this includes wastes containing mercury and its compounds, as well as sublimate, potassium chromate and cyanide, antimony. The toxicity of mercury compounds is due to the harmful effects of the Hg2+ ion. Mercury enters the human and animal body not in the form of ions, but when combined with protein molecules in the blood, forming metalloproteins after such compounds. In case of poisoning with the above-mentioned substances, a violation of the functions of the central nervous system occurs, damage to the kidneys up to their complete failure, which subsequently leads to the death of the victim;
2. highly hazardous waste; this includes waste containing copper chloride, copper oxalate, antimony trioxide and lead compounds. Their toxicity manifests itself, like any process of poisoning, accompanied by anemia, stomach ulcers, changes in the liver and kidneys, hemorrhage in the internal organs, death;
3. waste of a moderately hazardous class; this includes waste containing lead oxides, nickel chlorides, 4-carbon chloride. With prolonged exposure to the body, the number of red blood cells decreases;
4. low-hazard waste containing magnesium sulfates, phosphates, zinc compounds. This includes wastes resulting from the flotation method of mineral processing, where amines are used. Once in the body, phosphate dust leads to the development of pneumosclerosis, contraction of the bronchi and blood vessels. Human skin contact with phosphates can cause dermatitis characterized by rash, burning and itching;
5. Waste is non-hazardous and non-toxic.

The problems associated with the protection of the environment today occupy one of the first places among the urgently important tasks of mankind. Emissions from industrial enterprises into the atmosphere today reach such proportions that the tolerances for sanitary standards in relation to the level of pollution are exceeded several times. Tons of waste enter the biosphere in solid, pasty, liquid, gaseous form, thereby causing inestimable harm to nature, undermining its resources. In this regard, it became necessary to develop and implement new modern and safe methods for solving the problem of ridding the biosphere of its pollution by industrial and consumer waste. In order to choose a more rational way to solve this problem, a preliminary accounting of waste and their assessment is carried out.

After the waste is collected, it is assessed. Depending on this, the waste is processed, recycled or disposed of. Recycling is carried out on such waste that is useful in the future.

For example, used oils are cleaned from corrosion products, wear products, they are cleaned from suspended particles, thermal decomposition products, after which additives are introduced. As a result, oils are obtained for reuse.

Waste of rubber products, as car tires, crushed, then sent to a new production of the same products.

Mercury lamps are demercurized to produce mercury.

Spent nuclear fuel from nuclear power plants is processed at radiochemical plants. With such processing, plutonium and uranium are obtained, using them later in nuclear reactors.

Technological methods of waste processing and equipment, used for waste disposal of industrial enterprises, provide for the development of technological processes that include:

• reduction in the degree of chemical pollution of the environment toxic substances in waste disposal;
• improvement of equipment for the disposal and processing of waste, methods of their processing, methods for cleaning gas emissions into the atmosphere and treating wastewater.

Wastes that cannot be recycled and used in the future as secondary raw materials, that require complex and economically unprofitable processing, or that are in excess, that cannot be burned, cannot be neutralized, must be buried in landfills. It is advisable to use specially created storage facilities for the disposal of such waste, with the subsequent use of industrial waste in the future. When burying industrial waste, it is possible to use reservoirs of geological formations, such as granite, volcanic rocks, basalts, salt layers, gypsum, dolomite, clay, etc. Such storages can be built as independent storages, or they can be organized jointly with mining industries. With this disposal of waste certain conditions must be met:

• water resistance of layers and the presence of aquifers above and below them;
• exclusion of deformations arising from shear under the action of its own mass, dynamic loads, due to an earthquake, ground explosions that can make the water-conducting thickness;
• location of the storage near the settlement, the place of occurrence of floods, breakthroughs of dams and dams;
• available methods and means by which it will be possible to quickly and reliably "block" the workings through which waste is supplied to the goaf.

For underground waste disposal different depths and zones of hydrodynamics in the lithosphere are suitable, and therefore, the storage facilities are divided into shallow, medium-deep and deep. Underground tanks can also be created in unconventional ways using the energy of a camouflage explosion and a nuclear explosion. So, storage facilities for toxic industrial wastes are a complex geotechnical system with components of the geological environment, such as rock masses, groundwater. This also includes engineering structures of the ground-underground type, such as workings, wells and other types of communications.

explosive waste, which, after the creation of technologies for their processing and use, can be valuable and useful in the future, it is advisable to store in underground storage facilities, which are subject to increased requirements for ensuring safety and possible phlegmatization. The destruction of explosive waste is associated with a large investment in safety during the process. The location of storage facilities for explosive waste is subject to general protective measures for the storage of industrial waste. Mechanical type shocks, friction, exposure to high temperatures, electrical sparking or stray currents, chemical interactions between components, close explosion hazard can affect the waste and cause it to possibly explode. There are a number of separate requirements that apply to the storage of this type of waste:

• placement of explosive class waste in containers to prevent all types of the above mentioned impacts;
• remote location from power lines;
• laying a high-quality electrically conductive line for lighting utility rooms;
• protection from chemical interactions with other components, which is achieved at low storage temperatures and phlegmatization;
• careful methods of transportation and handling of explosive waste.

Landfills intended for the storage of industrial waste are temporary or intermediate destinations along the route of transporting waste to storage facilities. Placement of ground polygons in accordance with the rules for their design and creation is prohibited:

• next to fresh water deposits groundwater and their water protection zones;
• next to the located deposits of mineral waters (medical and industrial);
• near security resort areas;
• near nature reserves;
• among residential and recreational areas of settlements.

Toxic industrial waste can be neutralized by thermal methods. At this stage, there are many opportunities to reduce the amount of non-recyclable waste. Their chemical composition is always complex, so it is still quite difficult to process them into useful products, and it is also not economically feasible. Therefore, thermal methods for the neutralization of industrial waste are used:

1. Liquid-phase oxidation of industrial waste is used to neutralize waste in the liquid phase and sediment in wastewater. This method consists in the oxidation of organic and organoelement impurities of wastewater contained in the waste with oxygen. To implement the method, certain temperature values ​​​​of 150 - 350 ° C and pressure from 2 to 28 MPa are required. The intensity of liquid oxidation is favored by the high concentration of oxygen dissolved in water, which increases with high pressure. The parameters of pressure and temperature, the amount of impurities and oxygen itself, the duration of the process contribute to the oxidation of organic substances, in which organic acids (CH3COOH, HCOOH) or CO 2 , H 2 O and N 2 are formed. When organoelement compounds are oxidized in an alkaline medium, aqueous solutions of substances (chlorides, bromides, phosphates, nitrates, metal oxides) are formed. Liquid phase oxidation requires little energy compared to other methods, but is more expensive than these methods. Other disadvantages of this method include high corrosivity during the process: scale is formed on the heating surface. Some substances are not completely oxidized, wastewater with a high calorific value cannot be oxidized. The use of this method makes sense in the process of primary waste processing.
2. Heterogeneous catalysis finds application in the neutralization of industrial waste in gaseous and liquid phases. There are 3 varieties of heterogeneous catalysis of industrial waste. Oxidation of the thermal catalytic type is used to neutralize waste in the form of a gas that has few combustible impurities. On catalysts, the waste is oxidized at a temperature lower than the auto-ignition temperature of the combustible constituents of the gas. The nature of the impurities and the characteristics of the activity of the catalysts determine the oxidation temperature (250 - 400 °C), the oxidation process occurs in installations of various sizes. In thermal catalysts, CO, H 2 , hydrocarbons (HC), NH3, phenols, aldehydes, tar vapors, and carcinogenic compounds are successfully oxidized. During the oxidation process, CO 2 , H 2 O, N 2 are formed. To increase the specific catalyzed surface, porous ceramic plates made of aluminum oxide or oxides of other metals are used, which have catalytic activity.

In case of large amounts of dust and water vapours, do not use industrial type deep oxidation catalysts operating at max. 600 - 800 °C.

This method cannot be used also for the processing of waste containing high-boiling and high-molecular compounds. Substances are not completely oxidized, and the surface of the catalysts becomes clogged. The disadvantage of the method is the fact that it is not applicable to waste even with a small amount of P, Pb, As, Hg, S, halogens, which destroy catalysts.

The thermal catalytic type recovery finds application in the treatment of waste in the form of gas containing NOX. Vapor-phase oxidation by the catalytic method is used to transfer organic wastewater impurities to the vapor/gas phase, followed by oxygen-assisted oxidation.

It is better not to use heterogeneous catalysis methods as an independent method of waste neutralization, it is better to use it as a separate stage of the general technological cycle of neutralization.

Waste water containing inorganic substances with non-volatile properties can be neutralized by supplementing this process with the fire method or other methods of neutralizing industrial waste.

The following method of thermal disposal of industrial waste is pyrolysis. There are two different industrial waste pyrolysis processes: oxidative and dry pyrolysis.

Oxidative pyrolysis is a process of thermal decomposition of industrial waste, in which they are partially burned or in direct contact with the combustion products of the fuel. This method of thermal neutralization is used for many wastes that are "inconvenient" for incineration or gasification. These are wastes of a viscous or pasty state, wet sediments, plastics, sludge with a large amount of ash, earth with a large amount of fuel oil, oil and other compounds, wastes that are very dusty.

Dry pyrolysis is also a process of thermal decomposition of waste, but without access to oxygen. As a result of this process, pyrolysis gas is formed, which has a high calorific value, a product in liquid form and a carbonaceous residue in the solid state. This method of heat treatment of waste highly effectively neutralizes them and allows them to be used as fuel and chemical raw materials. This contributes to the development of low-waste and waste-free technologies, the rational use of natural resources.

There are low-temperature (450-550 °C), medium-temperature (max. 800 °C) and high-temperature pyrolysis (900 °C-1050 °C) depending on the temperature at which the process proceeds. The method of waste treatment by dry pyrolysis is becoming more widespread. Today, this is almost the most promising way to dispose of organic solid waste, which is characterized by the isolation of valuable components from these wastes.

The waste pyrolysis process is carried out in reactors with external and internal heating. The external type of heating is used in reactors designed in the form of vertical retorts, or in rotating drum reactors. In reactors, pyrolysis gases are not diluted with coolants, thereby maintaining a high characteristic of the calorific value. The gas produced in a reactor with an external type of heating contains a minimum of dust, because it does not mix with the gas coolant, which is a positive aspect of this equipment. Typically, the coolant is passed through a layer of waste containing fine particles.

In reactors with internal heating (vertical shaft type, with a fluidized bed, rotating drum type), gases are used as a coolant, but after they are heated to 600-900 ° C. These gases do not enter chemical reaction with waste (inert and combustible gases, without oxygen). It is best if the gas is circulating.

The disadvantage of this equipment is that in a reactor with internal heating, due to the use of gaseous coolants, the dust content of the pyrolysis gas increases. However, internal heating by convection makes the pyrolysis process intense and allows to reduce the dimensions of the reactors in comparison with reactors having external heating.

A few words should be given gasification method used for waste processing. The purpose of this method: obtaining combustible gas, resin, slag. Gasification is, like the methods described above, a thermochemical process carried out at high temperatures. In this process, the organic mass interacts with gasifying agents, while converting organic products into combustible gases. Gasifying agents are air, oxygen, water vapor, carbon dioxide, and mixtures thereof.

The gasification process takes place in mechanized mine-type gas generators. In this case, blast is used: air, steam-air and steam-oxygen. The advantages of gasification over incineration are as follows:

• use of formed combustible gases as fuel;
• the use of the resulting resins as fuel or chemical raw materials;
• the levels of emissions of ash and sulfur compounds into the air are reduced.

Disadvantages of gasification:

• when using air and steam-air blast, generator gas is formed with a low calorific value, unsuitable for transportation;
• it is impossible to process large-sized wastes of a pasty type, only crushed and loose wastes with gas-permeable characteristics are processed.

When using steam-oxygen gasification, a gas with a good calorific value is formed, which makes it possible to transport it over long distances.

Consider the following method of thermal processing of industrial waste. This is a fire method, which is based on the decomposition and oxidation of toxic components in waste at high temperatures. In this case, almost non-toxic or low-toxic products are formed, such as flue gases, ash. This method ensures the production of such valuable products as bleaching earth, activated carbon, lime, soda, etc. The chemical composition of industrial waste determines the content of flue gases (SOX, P, N 2 , H 2 SO4, HC1), salts of alkaline and alkaline earth elements plus inert gases. The fire type processing method used for industrial waste (toxic, chemical) is classified as follows, which is due to the type of waste and the method of their disposal:

• a simple way is to incinerate waste that can burn on its own; the combustion temperature with this method is min. 1200 - 1300 ° C. The disadvantage of the method lies in the fact that combustible waste may be of one value or another when further used in the future;
• the fire method by the oxidizing method is a complex process of several physical and chemical stages for the neutralization of non-combustible waste, used in the treatment of solid and pasty waste;
• the fire method in the recovery way is the destruction of toxic waste, which does not form by-products that can be further used as a separate raw material or an independent commercial product. Completely harmless products formed as a result of processing (flue gases, sterile slags) are dumped into dumps. This method can be used in the treatment of solid and gaseous emissions, MSW, etc.;
• with the help of fire regeneration, any reagents are extracted from the waste. This method restores the properties of spent reagents or materials. The positive qualities of this method are its environmental and resource-saving goals. However, to achieve these goals, it is necessary to determine the optimal temperatures by experiment, the duration of the process, the excess value of oxygen in the combustion chamber, and a uniform loading of waste, fuel and oxygen must be ensured. If these conditions are not observed, undesirable components appear in the flue gases. When neutralizing industrial waste by a purely thermal method or using catalysts, substances with organic elements that could become valuable raw material for target products, which is also a negative point.

In order to achieve a good degree of decomposition of industrial wastes, especially halogen-containing ones, a furnace designed for burning products must provide the necessary time for their stay in the combustion zone, good mixing of reagents with oxygen at a certain temperature. The amount of oxygen is adjustable. In order not to form halogens, but completely transform into hydrogen halides, an excess amount of water and as little oxygen as possible is necessary so that less soot is formed. If the temperature decreases at the time of decomposition of organochlorine products, this leads to the formation of dioxins, which are highly toxic and quite stable. This is also negative moment fire burning method. This gave impetus to the search for new technologies for the disposal of toxic waste.

A successful new direction based on application of low temperature plasma used in the disposal of hazardous waste. With the help of plasma, chemical waste is well neutralized ( chemical industry), including halogen-containing with elements of organic compounds, solid, pasty, liquid, gaseous, organic and inorganic wastes, of a weakly radioactive class, BO, admixture of carcinogenic substances are processed, subject to strict requirements for maximum permissible values ​​when released into air, water . Disposal of waste by the plasma method can be carried out in two ways:

• through the elimination of especially hazardous high toxicity waste by the plasma-chemical method;
• recycling of waste by the plasma-chemical method to obtain a commercial product.

The process of destruction of hydrocarbons, which promotes the formation of CO, CO 2 , H 2 , CH 4 , is most effective when using the plasma method. Plasma heating of hydrocarbons in solid and liquid form, which does not require consumption, promotes the formation of a gas semi-finished product (hydrogen with carbon monoxide). This synthesis gas has a certain value, it is used as steam for thermal power plants and in the manufacture of artificial liquid fuel, and the melt of the slag mixture is not harmful to the environment when it is buried in the bowels. Decomposition in the plasma torch of harmful products (polychlorinated biphenyls, methyl bromides, phenyl mercury acetates, chlorine- and fluorine-containing pesticides, polyaromatic dyes) occurs almost completely. As a result of decomposition, CO 2 , H 2 O, HC1, HF, P 4 O 10 are formed according to the following technologies:

• waste conversion process in air;
• in the aquatic environment;
• in the environment of steam / air;
• waste pyrolysis process at low concentrations.

Depending on the method of waste processing, it is possible to optimize the operation of the plasma torch for wastes with different chemical composition. The principle of operation of the plasma torch and its design are quite simple and are as follows: the process itself with the technology used takes place in a chamber with two electrodes: a cathode and an anode. They are usually made of copper, sometimes they are hollow. At a certain pressure, waste, oxygen and fuel are loaded into the chamber in predetermined volumes. Add water vapor. You can use catalysts. The pressure and temperature in the chamber are constant. When using the plasma method for processing waste in a reducing environment, valuable commercial products are obtained:

• acetylene, ethylene, HC1 and products based on them are obtained from liquid organic chlorine-containing wastes;
• in a plasma torch with hydrogen, during the processing of organic chlorine- and fluorine-containing wastes, gases are obtained with a content of 95 - 98% by weight of HC1 and HF.

For convenience, briquetting of wastes in solid form and heating of pasty wastes are used to convert the latter into a liquid phase.

For the processing of combustible radioactive waste(low and medium activity) a technology was developed based on the use of the energy of plasma jets of air. At the same time, activated hydrocarbon feedstock is introduced into pure form or containing galenides. This method contributes to the transfer of hazardous waste into an inactive phase with a decrease in their volume by several times. The disadvantage of this method is its energy consumption and the complexity of the process itself. Therefore, it is used for processing only those wastes, the processing of which by the fire method of neutralization does not comply with environmental requirements.

When collecting waste, they are separated depending on their further use, methods of their processing, disposal or disposal. This greatly simplifies and reduces the cost of their further processing, because the costs spent on their separation are significantly reduced. Waste recycling is the most important stage in ensuring the safety of their life, it serves to protect the environment from pollution and preserve natural resources.

During the smelting of metals, formation of metallurgical slags, during the formation of which the interaction of ore, fluxes, fuel occurs during high temperature. The composition of these slags is determined by the components of the interacting materials, their types, and the specifics of the metallurgical process. Ferrous metallurgy slags are subdivided into blast-furnace, steel-smelting, ferroalloy, cupola. The type of furnaces contributes to the production of open-hearth, converter or electrosmelting slags. A fairly common method of processing blast-furnace slags is granulation, which consists in rapid cooling with water, steam or air. This method As a rule, blast-furnace slags are processed, the utilization of which is about 60%. The main application of blast-furnace slags is found in the cement industry, where they serve as additives to raw materials in the production of Portland cements. There, by the way, the use of other slags, slowly cooled, is most common. Steel-smelting slags are utilized only by 30%.

Metallurgical slags are used for the preparation of crushed slag using a special technology. It is prepared by crushing slag from a dump, in which the slag has lain for about 5 months, becoming stable in composition. Crushed stone is cast. The molten slag is discharged in layers up to 500 mm thick. Slag crushed stone is also used in road construction. And slag wool is widely used as an insulating material.

Non-ferrous metallurgy slags are distinguished by their diversity, they have a significantly higher yield compared to ferrous metallurgy slags. Their disposal today has a number promising directions, consisting in their complex processing: first, non-ferrous and rare metals are extracted, and the remaining silicate residue is used for the manufacture of building materials, by analogy with ferrous metallurgy slags. Slags are also used in the secondary processing of metals, adding them to deoxidize steel, while saving scarce ferrosilicon. Their use as an abrasive material is allowed, which is used to clean the bottoms of ships. Converter slags are often used for backfilling dams, replacing soil with them. In order to recover iron from waste, the method of reverse flotation of tailings, direct flotation of ore, dry method of magnetic separation, and magnetic flotation method are used.

In addition to slag, many different types of dust and sludge are formed in metallurgy; they accumulate in dumps and sludge collectors. This waste does not contain anything: compounds of lead, magnesium, iron, sulfur and many other elements. Before use, the sludge is dehydrated (leaving a moisture content of up to 9%), harmful impurities are removed from them, subsequently adding them to the sintering charge. They are stored as mechanically or thermally formed pieces with the addition of astringents.

The next way to dispose of iron-containing dust is to include it in the charge when producing paint, cement, and dyes. When iron is released from a blast furnace, graphite dust is formed, which is graphite flakes that are released from the iron during its overflow. The demand for graphite is growing very strongly, it is used for the manufacture of electrodes, crucibles, molds are powdered with it before casting, it serves as an additive in the production of graphite-colloidal paints, etc. The production of diamonds, cermets, pencils also cannot do without graphite. So graphite dust from ferrous metallurgy enterprises is considered a valuable secondary raw material. Today, graphite dust is disposed of in two ways:

• enterprises with a large amount of dust grind it themselves, enrich it by the flotation method according to the usual scheme, then bring it up chemically and use it at their enterprise;
• graphite dust is enriched at metallurgical enterprises with subsequent processing of the concentrate at graphite enterprises.

Thus, both graphite dust and sludge (ash- and sulfur-containing) have another direction of utilization: they are used in agriculture as an ameliorant for various soils, such as acidic, podzolized, for example. Sludge neutralizes soils with high acidity.

Wastewater from the pipe-rolling industry contains scale and oils of various kinds. During cleaning, scale is separated, which is utilized as an additive to the sintering charge. In the case of strong oiling of scale, it is treated with steel-smelting slag in the liquid phase. Scale-enriched slag is a valuable metallurgical product when solidified.

To resolve the issue of disposal of slags and ashes, a number of technical issues should be resolved to develop prerequisites for their use, units and technologies for their processing, to study the psychology of consumers of secondary mineral products.

The existing waste disposal technologies on the market today were analyzed and the following conclusion was made:

All technologies offered on the market today for the disposal / thermal treatment of industrial waste are based on pyrolysis methods or their varieties, incineration, which requires huge amounts of gas or diesel (plasma). Both pyrolysis itself and many of its varieties have existed for over a hundred years, but are used in industry, or in the processing of pure products (coal, wood, oil), or pyrolysis boilers are used with a cycle load. In the first case, we are talking about the pyrolysis method, for example, in the oil refining industry, in the second we are talking about clean waste disposal. In both cases, we are talking about the disadvantage of the pyrolysis method as a problem associated with the formation of tar deposits in the presence of sulfur and other hazardous elements. This results in frequent equipment shutdowns, equipment breakdowns, accelerated metal corrosion and even fires. The trouble-free operation of such equipment is associated with frequent preventive maintenance, cleaning of boilers (and there must be at least 3 of them, since the operation mode goes in cycles), etc.

Gas cleaning pyrolysis is also a big problem today. During this process, it is necessary to neutralize the highly carcinogenic ash collected by the scrubber. Plasma utilizers do not have this problem, carbon deposits do not form, but plasma is not so easy to obtain, it can only be used when disposing expensive materials.

Today, for the neutralization of hazardous waste, there is equipment based on the use of microwave energy, but all the technologies available today are carried out in cycles, it practically disinfects waste, and the temperature in the chamber does not exceed 130ºC.

Today, more and more new developments of equipment appear on the market, new generation equipment capable of neutralizing, utilizing various types of waste and materials, with unique microwave gas cleaning systems. These technologies, which are being worked on by research companies and institutions in Europe, are based on the action of a high concentration microwave field on neutralized materials or hazardous gases.

With the help of two new technologies (MTO - microwave thermal treatment and MOG - microwave gas oxidation), various types of waste are neutralized or disposed of, while microwave equipment operates continuously, providing a positive energy balance.

Microwave units are rightly called "omnivorous", because they are able to dispose of any waste: from biological to pesticides, including medical waste. The loading system is configured individually for the material being recycled, in accordance with the customer's assignment, operating parameters and functional modes of the equipment. The innovative method works on instant heating of waste up to 1000 °C with a high concentration of microwave energy and has many positive factors:

• materials are heated throughout the volume;
• the process environment is controlled: in the absence of oxygen or in its deficiency (various gases), or in an excess environment);
• types of waste determine the supply of air or inert gases to the equipment chamber;
• emissions of a small amount of gases are effectively neutralized (afterburning takes place in the MOG chamber);
• on the equipment it is possible to carry out pyrolysis of organic substances, while regulating the stabilization of pyrolysis gases;
• it is possible to carry out gasification of organic substances (partial or complete);
• waste incineration (partial or complete).

The issues of industrial waste disposal are of concern to scientists all over the world, since today there is no single integrated approach to the issues of processing and using secondary products and industrial waste. This topic is also of great importance in the context of respect for the environment. The topic of waste disposal in our country outlines a number of issues that are simply necessary to solve and are considered possible only in conjunction, with the involvement of specialists in various fields: technologists for the production part of the process, medical workers, environmental service workers and economists. The issues of disposal of chemical waste are constantly worrying scientists around the world. Evidence of this is the emergence of many new devices and methods that are intended to at least slightly change such a sad situation in this area in a positive direction. Some believe that the easiest way out is to ship waste off the earth, all processing plants should be moved to space, and all new plants should be built in Earth orbit, from where all industrial waste will immediately go to the sun. But these are all expensive projects of the future, and if they are ever implemented, then only for waste, which poses a real danger to humanity.

Description

Furnaces (installations) for waste and garbage incineration is a compactly assembled technological line for the thermal disposal of liquid, biologically hazardous waste, waste in the petrochemical and chemical industries, as well as various equipment used for the disposal of solid industrial waste and garbage.

The purpose of waste and garbage disposal by incineration is to reduce the volume and mass of waste and garbage.

Temperature of burning of industrial wastes and garbage: from 700 to 900°C.

Afterburning of exhaust gases occurs at temperatures up to 1200°C, which ensures complete decomposition and combustion of complex organic compounds.

Advantages of using furnaces for incineration and disposal of waste and garbage:

• Full disposal of waste and garbage at the place of their formation
• An excellent way to recycle various polymers (polyethylene, PVC, polystyrene, etc.)
• Solving the problem of waste and garbage disposal and improving the environment, full compliance with industrial safety requirements
• A wide range of incinerated waste and garbage
• Utilization of heat used for own needs
• Highly efficient gas cleaning system

The principle of operation of furnaces (installations):

1. Preliminary preparation of the processed material - mixing with sand using a loader to the required consistency
2. Calculation of the amount of heat required for the utilization of the source material (given by the physical properties of the processed material, the actual working temperature determined depending on the current indicators).
3. The automatic burner provides constant heating of the processed product. The burner is the key device of the furnace, the operating parameters of the burner determine the main technical indicators of the entire installation. Furnace and burner are insulated with double stainless steel sealing plates.
4. The combustion of hydrocarbons takes place in the furnace. Forced ventilation is created using a fan mounted on a rotary kiln.
5. The inlet of the secondary chamber is designed to allow turbulent mixing with the combustion air and the ignition burner flame. The residence time of the gases in the secondary chamber guarantees the complete combustion of all hydrocarbons.
6. The auxiliary blower provides a constant supply of air necessary for the combustion process. The amount of air is controlled by a continuous oxygen sensor.

Complete set (scope of delivery) of furnaces and installations for incineration and recycling of waste and garbage:

• rotary kiln with burner
• cyclone (dust cleaning device)
• secondary chamber, receives hydrocarbons from a rotary kiln
• hopper with vibrating sieve
• double auger
• band conveyer
• oven feed screw
• kiln discharge conveyor
• cyclone conveyor
• screw mixing conveyor
• control system

Incineration and pyrolysis of municipal solid waste

Experience shows that for large cities with a population of more than 0.5 million inhabitants, it is most expedient to use thermal methods for the disposal of solid waste.

Thermal methods of processing and disposal of MSW can be divided into three methods:

- layer combustion of initial (unprepared) waste in waste incineration boilers (MSK);

- layer or chamber combustion of specially prepared waste (freed from ballast fractions) in power boilers together with natural fuel or in cement kilns;

- pyrolysis of wastes with or without preliminary preparation.

Despite the heterogeneity of the composition of municipal solid waste, they can be considered as low-grade fuel (a ton of waste gives 1,000-1,200 kcal of heat when burned). Thermal processing of MSW not only neutralizes them, but also allows you to receive thermal and electrical energy, as well as extract the ferrous scrap metal contained in them. When incinerating waste, the process can be fully automated, and therefore, the maintenance personnel can be drastically reduced, reducing their duties to purely managerial functions. This is especially important given that staff have to deal with such unsanitary material as MSW.

Layer combustion of MSW in boiler units. At this method neutralization, all waste entering the plant is incinerated without any preliminary preparation or treatment. The method of layered combustion of initial waste is the most common and studied. However, incineration produces a large amount of pollutants, so all modern waste incineration plants are equipped with highly efficient devices for capturing solid and gaseous pollutants, their cost reaches 30% cap. costs for the construction of the MSZ.

The first waste incineration plant with a total capacity of 9 t/h was put into operation in Moscow in 1972. It was intended for burning residues after composting at a waste processing plant. The incineration shop was located in the same building with the rest of the plant, which was closed in 1985 due to the imperfection of the technological process and the resulting compost, as well as due to the lack of a consumer for this product.

The first domestic waste incineration plant was built in Moscow (special plant No. 2). The operating mode of the plant is round-the-clock, seven days a week. The heat generated from waste incineration is used in the city's heating system.

In 1973, the CKD-Dukla enterprise (CSFR) acquired a license from the Deutsche-Babkok company (Germany) for the manufacture of MSCs with a roll grate. According to foreign trade relations, boilers manufactured by this enterprise were purchased for a number of cities in our country.

In 1984, the largest domestic waste incineration plant was put into operation in Moscow. Plant No. 3. The capacity of each of its four units is 12.5 tons of incinerated waste per hour. Distinctive feature unit - an afterburner drum installed behind a cascade of tilt-and-push grates.

The operating experience of domestic plants made it possible to identify a number of shortcomings that affect the reliability of the main technological equipment and the state of the environment. To eliminate the identified deficiencies, it is necessary:

-ensure separate collection of ash and slag;

- provide for the installation of backup conveyors for the removal of ash and slag waste;

- to increase the degree of extraction of ferrous scrap from slag;

- ensure the cleaning of the extracted scrap metal from ash and slag contamination;

- provide for additional equipment for packing the recovered ferrous scrap;

-develop, manufacture and install a technological line for the preparation of slag for recycling;

Installations or plants for the processing of municipal solid waste by pyrolysis operate in Denmark, the USA, Germany, Japan and other countries.

The intensification of scientific research and practical developments in this area began in the 70s of the twentieth century, during the "oil boom". Since that time, the production of energy and heat from plastic, rubber and other combustible waste products by pyrolysis has been considered as one of the sources for the generation of energy resources. Particularly great importance is attached to this process in Japan.

high temperature pyrolysis. This method of disposal of solid waste, in essence, is nothing more than gasification of garbage. The technological scheme of this method involves the production of secondary synthesis gas from the biological component (biomass) in order to use it to produce steam, hot water, electricity. An integral part of the process of high-temperature pyrolysis are solid products in the form of slag, i.e., non-pyrolyzable residues. The technological chain of this recycling method consists of four successive stages:

1. selection of large-sized objects, non-ferrous and ferrous metals from garbage using an electromagnet and by induction separation;

2. processing of prepared waste in a gasifier to produce synthesis gas and side chemical compounds - chlorine, nitrogen, fluorine, as well as slag during the melting of metals, glass, ceramics;

3. purification of synthesis gas in order to improve its environmental properties and energy intensity, cooling and entering it into a scrubber for cleaning with an alkaline solution from pollutants of chlorine, fluorine, sulfur, cyanide compounds;

4. combustion of purified synthesis gas in waste heat boilers to produce steam, hot water or electricity.

When processing, for example, wood shavings, synthesis gas contains (in%): moisture - 33.0; carbon monoxide - 24.2; hydrogen - 19.0; methane - 3.0; carbon dioxide -10.3; nitrogen - 43.4, as well as 35-45 g / nm of tar.

From 1 ton of solid waste, consisting of 73% MSW, 7% rubber waste (mainly car tires) and 20% coal, 40 kg of tar used in the boiler room and m3 of wet gas are obtained. The volume fraction of dry gas components is as follows (in%): hydrogen - 20, methane - 2, carbon monoxide - 20, carbon dioxide - 8, oxygen - 1, nitrogen - 50. Net calorific value 5.4-6.3 MJ/m3 . The slag is 200 kg/t.

waste incineration is an old tradition. Since ancient times, people sent to the oven what was not useful for livestock feed or fertilizing the land. The people of Austria, back in early XIX For centuries, they learned to burn garbage, because they had to pay a tax, the size of which was proportional to the volume of garbage removed.

In most European private houses in the 20th century, incinerators were installed. But, despite the effective reduction of waste, the method turned out to be not safe - leaks of harmful gases quite often occurred.

England was the first to burn garbage in factories in 1870. The workers simply threw it into the stove, and removed the ashes from there.

In 1893, near Paris, the first garbage incineration plant was built, which caused disapproval of agronomists - why destroy organic waste if it can be used usefully as fertilizer. At first, their opinion was listened to, but in 1906, organic waste was again allowed to be destroyed if there was no buyer for them.

At first, traditional fuels, such as coal or fuel oil, were added to the garbage. Over time, the equipment has been improved. In 1930, a grill oven appeared, which significantly increased efficiency (burned up to 90% of the mass) and facilitated human labor.

Waste can turn into fuel. Similar to low-grade coal. But only on condition that they remove wet organic waste, iron, glass.

The incineration plant, among other things, will need filters to purify the smoke before it is released into the atmosphere. Since it contains harmful gases and particles called "fly ash" (particles ranging in size from fractions of a micron to 0.14 mm). It is also necessary to filter out volatile compounds of heavy metals, gaseous hydrochloric acid.

The solid residues remaining after cleaning (35-50 kilograms of toxic substances per ton of waste incinerated) are chemically stabilized or pressed, and then sent to specialized storage facilities as “hazard class 1 waste”.

When burned, slag remains. They can be useful in the steel industry, for producing aluminum wires, after screening - for laying the underlying soil when laying roads designed for light loads, such as pedestrian and parking lots. True, the use of such slags is subject to strict regulations, because they may contain toxic inclusions and residues of combustible substances.

The technology of heat treatment and destruction of waste is used primarily by developed countries. For example, Japan, Belgium, Germany, France, the Netherlands, Switzerland, Sweden, Austria, Denmark. The number of factories does not increase, but their sizes increase.

Disadvantages of incineration technology

• Harmful chemical compounds and microparticles hazardous to health and the environment, too small for filter cleaning.
• Furnaces require a constant load, so there is a high probability of burning raw materials that could be recycled.

The Council of the European Union at one time issued a dozen directives regulating waste management, including: limits for emissions of harmful substances into the atmosphere, the availability of permits from enterprises, operating conditions, control and measurement of substances.

The Waste Directive of 15 July 1975 stipulates that waste must be disposed of without damage to human health and without damage to the environment. The directive of June 1989 dealt specifically with air pollution from garbage incineration.

In 2000, the European Union issued an even stricter waste incineration regulation. Article 6, not much different from the conditions for the operation of recycling enterprises, described in the directive of 1989:

The gases released during combustion must be heated for at least 2 seconds, at a temperature of at least 850 °C. If hazardous wastes containing more than 1% halogenated organic compounds (eg chlorine) are incinerated, the temperature must be 1100 °C minimum. If the temperature drops, the burners should turn on automatically.

If the emission limits are exceeded, under no circumstances should the waste incineration be continued for more than four hours of continuous operation. During the year they should be recruited no more than 60 hours.

Factories had to reckon with this newer regulation and acquire new smoke treatment equipment, the cost of which is up to two-thirds of all costs.

In Art. 6 (point 1) the need for 2 seconds of heating the smoke at a temperature of 850 ° C is prescribed, for the destruction of dioxins and furans - in total about 20 compounds of varying degrees of toxicity. Also, the surviving dioxins are absorbed by activated carbon or decomposed by means of catalysts. Despite precautions, poisoning of livestock, people and the environment still occurs. For example, in Savoy, dioxin poisoning from incinerator fumes led to the slaughter of 7,000 head of cattle in 2001.

Explosion at the chemical plant of the Swiss pharmaceutical company Hoffmann-La Roche in Seveso (Italy) in 1976.

After an explosion at a chemical plant in the city of Seveso in Italy, a cloud with a high concentration of dioxin spread over an area of ​​16 square kilometers and caused mass poisoning of people and pets. In fact, dioxin emissions at the plant are controlled (with the exception of emergency situations). More powerful sources are burning landfills, bonfires, in which garbage and plant waste are burned, including in garden plots. Their combustion temperature is relatively low - up to 600°C. In this mode, dozens of times more dioxins and furans are formed than in waste incinerators, where a high-temperature process (about 1000 ° C) is used. If the technology is followed, the amount of harmful emissions will be close to the prescribed European standards.

In France, in 2007, the Isseana plant was built to heat 79,000 dwellings and generate electricity for 50,000 apartments. Heeding environmentalists, the administration deliberately lowered production rates to encourage the people of Ile-de-France to reduce their waste by resorting to more complete pre-sorting in order to increase the amount of recycled raw materials. The sorting shop also contributes to the same.

Waste incineration plants have been renamed "enterprises for the use of waste as energy raw materials." Simply destroying waste by incineration is inefficient and unprofitable; it is necessary to pre-sort the waste and reuse it. And burn the remains using the resulting heat. At the government level, in Germany, in the Netherlands, in the Scandinavian countries, they decided to reduce the amount of waste through sorting, processing and recycling.

WASTE INCINERATION - disposal of waste by burning at special installations (incinerators).[ ...]

Hazardous waste. Hazardous wastes are those containing pathological, explosive, radioactive or poisonous substances. Incinerator residues or ash in household waste can ignite in waste collection or disposal facilities. Waste liquid and solid materials that present a hazard are, in some cases, collected in containers and included in the general solid waste stream. The waste collection team must identify all hazardous waste. Hazardous waste is handled separately from the rest with the adoption of appropriate safety measures. Ordinary and special machines to collect waste, it is necessary to provide fire extinguishing equipment and protective clothing used when handling hazardous materials.[ ...]

Incineration of waste solvents must be carried out either in a special installation on the territory of the enterprise, or, in agreement with the local sanitary and fire authorities, at specially designated landfills.[ ...]

Waste incineration in a plant with a capacity of 40-45 tons/day exacerbates the environmental situation, since chlorine and organic compounds are present in the sludge. Their combustion at a temperature of 750°C inevitably leads to the formation of dioxins that enter the atmosphere.[ ...]

Incineration of waste plastics is the least effective way to remove and neutralize them, since it completely destroys the expensive polymer and other plastic components. It is used in the processing of waste plastics only in cases where other methods cannot be used for technical or economic reasons. In particular, the incineration of waste plastics is used when their separation from a mixture of other wastes is impossible or too expensive.[ ...]

Burning waste in incinerators reduces the volume of waste by 70 to 90%, depending on the composition. The densely populated and most significant cities of the world actively introduced experimental furnaces. The heat released from the burning of garbage began to be used to generate electricity, but these projects were not able to justify the costs everywhere. The high cost of them would be appropriate if there were no cheap way of burial. Many cities that used these stoves soon abandoned them due to the deterioration of the air composition. Waste disposal remains one of the most popular methods for solving this problem.[ ...]

Waste incineration. The first oven for Waste incinerator, considered as a waste incinerator, was built in England in 1874. The development of the industrial revolution in Great Britain led to the emergence of waste having a relatively high calorific value. The cholera epidemic in 1892 hastened the construction of Europe's first waste incinerator (Hamburg, Germany, 1983). This installation operated until 1924. In the same city in 1912 and 1913. two other waste incinerators were built. In England, by 1914, there were already 200 waste incinerators (65 of them were used to obtain energy from steam generators installed there) in 160 cities.[ ...]

The combustion of waste oils can be realized using a turbo sparging method. The process includes the following stages: waste supply, crushing, evaporation, mixing of fuel with air, ignition and combustion. The principle of operation here is that air is passed through the layer of burnt waste oils, intensively mixing the layer of liquid waste. At the same time, another air stream is introduced tangentially into the combustion chamber. The total amount of air introduced must be sufficient for complete incineration of the waste. The turbo-bubbling combustion method is implemented in several versions of the Vikhr plant. However, it is necessary to carry out preliminary dehydration of combustible waste. The turbo-bubbling method belongs to the nozzleless type of furnace processes, and in furnaces of this type, the function of the spraying device is performed by the foam layer.[ ...]

Waste incineration in waste incineration plants. In developed countries, part of MSW is destroyed in special waste incinerators. At the same time, in some cases, electricity is generated, in others - steam, which is used to heat nearby enterprises or residential areas. In Russia, this method is not widely used, mainly because the foreign technologies used at these plants cannot cope with unsorted Russian waste.[ ...]

When waste is incinerated in drum kilns, in principle, it is possible to achieve higher combustion temperatures, but high-temperature incineration of MSW leads to rapid wear of a rather thin lining in furnaces of this type (once every six months, it is necessary to replace the inner lining of the furnace - a laborious, complex and expensive operation, its cost is about 10% of the cost of the furnace itself). To increase the durability of the furnace, sometimes instead of lining, water cooling of the drum wall is used or cooling of the furnace lining is arranged. The productivity of drum kilns is up to 10 t/h (usually 1-5 t/h).[ ...]

The mode of waste incineration (temperature, duration, blowing air consumption) cannot be arbitrary and must ensure the decomposition of very dangerous organic substances formed from some plastics - dibenzodioxins and dibenzofurans to harmless compounds. Numerous studies and practice of operating foreign plants show that these substances, which are very dangerous for human health, decompose by 99.9% at a temperature of 900 - 1000 ° C. At the same time, at most domestic plants, the combustion temperature does not exceed 800 ° C (primarily due to the unpreparedness of waste for incineration).[ ...]

Open burning of waste in landfills or in yard ovens is the most primitive form of incineration and is currently banned in the United States due to the risk of air pollution.[ ...]

Waste disposal. One of the most simple ways elimination of plastic waste is their incineration. Developed and continue to improve various designs combustion furnaces: hearth, rotary, fluidized-bed nozzles, etc. Preliminary fine grinding and spraying of wastes at a sufficiently high temperature ensure their almost complete conversion into CO2 and H2O-However, the combustion of some types of polymers is accompanied by the formation of toxic gases: hydrogen chloride, nitrogen oxides, ammonia, cyanide compounds, etc., which necessitates measures to protect atmospheric air. Moreover, despite the significant thermal energy incineration of plastics, the economic efficiency of this process is the lowest compared to other processes for the disposal of plastic waste. Nevertheless, the comparative simplicity of the organization of combustion determines the fairly widespread use of this process in practice. A typical technological scheme of waste incineration using a tube furnace is shown in Fig.[ ...]

Waste incineration products are non-toxic ash and flue gases, which are cleaned using standard equipment. At the same time, the emission of harmful substances does not exceed! There is no established value of maximum permissible concentrations.[ ...]

Waste incineration costs have changed dramatically between 1965 and 1975 for a number of reasons.[ ...]

However, before incineration, the waste must be cleaned of unwanted components, and after incineration, exhaust gases must be carefully neutralized. World practice has accumulated significant experience in waste disposal by incineration. The main obstacle to the widespread use of this method is the complexity and high cost of exhaust gas purification systems.[ ...]

Waste incinerator project "Volund" type. The crane lifts the waste and throws it into the furnace through a funnel-shaped chute. The first section of the furnace consists of a grate-dryer, on which the material is exposed to heat radiated from the walls of the furnace. This process produces steam and some gases. The speed at which the waste moves is controlled so that the waste is well dried before it passes to the next chamber.[ ...]

For the destruction of petrochemical waste, furnaces of complex design and very simple devices are used. The latter include an open vertical shaft with a section of 2.4x2.4 m with a tiled floor, on which waste is burned. Air blast is supplied to the upper part of one of the walls of the shaft through special nozzles with a diameter of 50 and 75 mm. Fan power - tor - 77.5 m / min per 1 running. m of the blast line at a pressure of 250-375 mm of water, art. In installations of this type, many solid and liquid wastes are successfully incinerated, ash remains in the furnace, which is periodically unloaded.[ ...]

As experiments on the combustion of aqueous solutions of some organic substances and bottom residues of a number of industries have shown, their fairly stable and complete combustion in chambers with small heat losses in environment(¿/о.с 5%) is observed at 1300 °С, and this temperature is necessary and sufficient for independent combustion of waste. In combustion chambers with large heat removal through the walls, an additional condition for stable and complete combustion of the waste without the use of additional fuel is to ensure the required temperature of the exhaust gases from the combustion reactor. So, when burning wastes containing low molecular weight oxidized hydrocarbons, this temperature should be o.g 950 °C. Recommendations for choosing ¿0.g for other combustible substances are given in Ch. 5.[ ...]

Experts believe that the incineration of organochlorine wastes under certain, specially created conditions is the most reliable and economical way to neutralize them. In the technology of recycling waste from organochlorine production, various schemes for incinerating waste with subsequent capture of hydrogen chloride and the release of commercial hydrochloric acid have gained some popularity.[ ...]

The main useful product of waste incineration is usually the heat of waste gases used as a secondary energy source to generate steam, electricity, hot water for industrial and domestic needs.[ ...]

Calcination is the incineration of waste, carried out in order to reduce the volume and mass of the reacting components. However, the calcination process generates wastes (ash and slag, flue gases, fly ash and waste water from ash handling and flue gas cleaning) that adversely affect the environment. Therefore, incineration is not the best way to dispose of solid organic waste.[ ...]

The principle of the turbo-bubbling combustion method is that the so-called primary air is passed through the layer of combusted oil waste, intensively mixing the layer of liquid oil waste. At the same time, secondary air is tangentially fed into the combustion chamber. The total amount of air introduced must be sufficient for the complete incineration of the waste.[ ...]

The Japanese Patent discloses an oil waste incinerator which consists of several flow chambers. The volume of the chambers is gradually decreasing. Waste enters the first, largest combustion chamber, adapted for combustion, then the residue sequentially passes into subsequent afterburning chambers. The flue gases are cleaned with a jet of water and filtered, and the waste water with impurities is also filtered and removed through a pipeline at the bottom of the furnace.[ ...]

From production shops Waste is supplied to the incineration section both through pipelines and in containers. The departments have working, overflow and reserve tanks for storage and preparation of waste. Some of the tanks are equipped with devices for heating and mixing waste. Each container is equipped with a level gauge, the readings of which are displayed on the control panel. The temperature and flow rate of the waste fed into the furnace were not always measured, although these measurements are provided for in the project.[ ...]

Experience shows that industrial and domestic waste can be extremely dangerous for humans and nature, especially those that contain super-ecotoxicants 155-58]. Problems arise not only during waste storage or disposal, but also during incineration. For a long time it was believed that thermal technologies can effectively neutralize toxic waste with the formation of non-toxic substances. Meanwhile, the data of the last 10-15 years indicate that waste incineration is a source of a constant supply of super-ecotoxicants, such as dioxins, into the environment 59-61 .[ ...]

The next most effective method is incineration of garbage. New types of incinerators produce waste, which is an excellent material for storage, and the resulting heat can be used to generate steam (heating buildings) or generate electricity. However, this method has significant drawbacks. The population is opposed to this method (as well as to sanitary earth fillings). Waste incineration residue can also be a source of pollution, as its leaching products can enter ground or surface water. Recently released air pollution control standards have greatly increased the cost of incinerating waste.[ ...]

The classification of combustion devices for waste incineration is based on aerodynamic characteristics as the most important, since they determine the supply of oxidizer to the reacting surface, which has the greatest effect on the specific heat output and efficiency of the combustion process. In this regard, there are layered furnaces - for burning lumpy fuel, for example, non-crushed municipal solid waste (MSW), and chamber - for burning gaseous and liquid waste, as well as solid waste in a pulverized (or finely crushed) state. The combined method of combustion is implemented in torch-layer furnaces. A special place in this classification is occupied by bubbling and turbo-bubbling furnaces for burning liquid waste. Bubbling devices are sometimes traditionally referred to as burners.[ ...]

Living in a civilization creates mountains of solid waste, which is not at all easy to get rid of. The first step is waste incineration. Most organic waste is oxidized to CC>2 and water during combustion. After incineration, the volume of waste is significantly reduced; valuable elements such as chromium, molybdenum, and lead can be recovered relatively easily from residues, and the heat generated by incineration can be put to good use. The end products, which consist mainly of silicon and aluminum compounds, are of little value. Approximately 25.7% of all minerals consists of silicon and 7.4% of aluminum. Iron is also abundant and is the fourth most abundant element. Some end products can be used in the construction of buildings, roads and highways if the combustion temperature is high enough. Further, a certain amount can be used in earthworks, such as the construction of dams, embankments and for soil improvement. The remains (no more than 10% of the original volume) can only be thrown away and buried, therefore, we need to think about where it is better to do this.[ ...]

Sources of superecotoxicants are toxic waste incinerators. US only total hazardous waste subjected to incineration is more than 4 million tons per year. However, despite the widespread use of waste incineration plants (in particular, using furnaces of cement plants), none of the technologies meets the requirements of environmental safety. The main argument against incineration technologies is the pollution of atmospheric air with toxic substances and the creation of new, potentially hazardous wastes (fly ash, sludge), which, in turn, require disposal in landfills. Many experts believe that hazardous waste incinerators are the same landfills, but posing an even greater environmental threat.[ ...]

According to C. Mantell, emissions of dust particles from waste incineration into the atmosphere range from 4 to 27 kg per 1 ton. For good furnaces, these emissions are 1% of the amount of waste burned. But even so, large stations emit thousands of tons of harmful dust and gases into the atmosphere per day. If we also take into account the unprofitability of obtaining thermal energy obtained by burning waste, then this method of eliminating precipitation rather indicates an unsatisfactory solution to this important problem. Therefore, the generally accepted opinion about the possibility of using the method of burning sludge is completely fair only when no other more efficient way of using sludge is possible.[ ...]

In our country, the content of only four harmful components in the composition of waste gases from waste incineration is regulated: solid particles (dust), oxides of sulfur, carbon and nitrogen. At the same time, abroad, in the first place, the most dangerous, specific for waste, harmful emissions are normalized: heavy metals (in total and individually - zinc, cadmium, lead, copper and mercury), organic substances (dibenzodioxins and dibenzofurans), as well as hydrogen chloride and fluoride.[ ...]

For many years, energy recovery has been practiced by burning specialized waste, especially wood chips. This problem is of particular interest in countries with more expensive fuel than in the United States, especially in Western Europe and Japan. Due to the shortage of oil and gas for domestic use and the increase in the cost of energy, the problem of its separation from solid waste is becoming more and more urgent in the United States. In order to put this energy into perspective, it should be noted that the available energy in all US municipal solid waste is approximately 1.69-1015 kJ per year, or less than 3% of the total US energy demand. It can be concluded that the incineration of solid waste can become a significant source of energy, but in itself will not provide a solution to the energy crisis. It can also be noted that when waste is burned, carbon returns to the atmosphere faster than when it is buried in the ground, which makes it possible to accelerate the natural process of the carbon cycle through photosynthesis (although the contribution of combustion to the carbon cycle is insignificant).[ ...]

On fig. 9.8 shows a general view of the plant, which implemented layered combustion of waste in a drum rotary kiln.[ ...]

One of the most common and effective methods disposal of waste is their incineration. At the same time, organic waste is completely gasified; in the presence of inorganic impurities, ash is also formed. The resulting gases contain, in general, carbon dioxide in water, as well as nitrogen in the air. During the half-burning of wastes consisting of hydrocarbons and oxygen-containing compounds, flue gases directly enter the atmosphere. If the waste contains appreciable amounts of heteroatomic compounds containing sulfur, halogens, nitrogen and metals, the gaseous products of combustion must be subjected to secondary treatment before being released into the atmosphere to bring the content of harmful components to MPC standards. After that, the gases are emitted into the atmosphere, and the resulting small amount of solid waste is stored.[ ...]

Purification of flue gases from nitrogen oxides. To reduce emissions of nitrogen oxides from fuel units and waste incinerators, various technological processes are used. Primary measures that reduce the formation of nitrogen oxides to a limited extent relate to the design of the furnace space and combustion processes. In secondary measures, the possibility of reducing nitrogen oxide emissions in the path of flue gases between the economizer and the air heater or between the electrostatic precipitator and the chimney is used.[ ...]

NPO Algon (Moscow) has developed and is implementing a process for high-temperature processing of solid household and industrial waste (Fig. 17). The main unit is a bubbling furnace, in the liquid slag bath of which intensive mixing (using an oxygen-enriched gas jet) and burning of waste at 1400-1600 °C take place. There is no need to carry out preliminary preparation of waste and their sorting. When burning, the complete decomposition of harmful compounds, the complete oxidation of combustible components occurs. In the process of waste incineration, their mineral part passes into a slag melt suitable for the production of environmentally friendly building materials: stone casting, crushed stone, mineral fiber and concrete fillers. In metallurgical production, the process makes it possible to obtain pig iron directly from raw ore and any iron-containing materials (chips, pellets, waste, etc.) using any coal, which significantly reduces material costs. The technology for processing household waste has been developed at the Ryazan Pilot Plant of Gintsvetmet.[ ...]

Garbage from urban waste can also pollute the atmosphere. The ego depends on the methods of destroying it. In many cities, waste processing is carried out centrally, but open burning of waste in the air is also practiced, which significantly pollutes it. Even when waste is burned in closed furnaces, a large amount of fly ash, nitrogen oxides and sulfur oxides are released into the atmosphere.[ ...]

The heat treatment method for the purpose of sludge dehydration is widely used abroad. In 1995, about 85% of solid toxic waste at chemical plants of Union Carbide, USA, was either disposed of, incinerated or treated to reduce its volume and toxicity. In Switzerland, Denmark and Japan, waste incineration is the dominant technology (70%)[ ...]

The productivity of the installation is 1.3-3.0 t/h of oil sludge, which is 2-4 times higher than the productivity of the above-described installation with a fluidized bed furnace. Waste incineration at a modern petrochemical plant of optimal capacity can ensure the operation of a power station with a capacity of 1 million kW.[ ...]

The given data from world practice show that the main methods of neutralization and destruction of solid industrial waste are chemical neutralization and incineration. The method of waste incineration, due to the greatest radicalism, has become the most widespread. However, it is impossible to consider waste incineration as the only method of their elimination and neutralization, since in addition to negative aspects process (complexity of equipment, the presence of flue gases, etc.) there is a loss of waste as a raw material resource. Therefore, in recent years, in world practice, more and more importance is attached to the processing of all types of waste in order to obtain various products.[ ...]

In the USSR, the design of landfills for the centralized processing of software is regulated by the sanitary rules “Procedure for the accumulation, transportation, neutralization and disposal of toxic industrial waste”, approved by the Chief State sanitary doctor USSR December 29, 1984 N 3183-84. The requirements of these rules apply to the design, construction and operation of landfills only for the disposal and incineration of industrial waste, for which disposal methods have not yet been developed.[ ...]

The introduction of stricter environmental standards in the West, as well as public opposition, led many companies to head to the countries of Eastern Europe looking for new markets for waste disposal.[ ...]

The main node of this system is a fluidized bed incineration plant at a temperature of 730 C. The exhaust gases of this plant are cleaned in a scrubber irrigated with water before being released into the atmosphere and practically do not contain soot and any foul-smelling impurities.[ ... ]

Hydrogen chloride is sometimes present in the air in workplaces when hydrochloric acid is used as an etching and cleaning agent for metal and ceramic surfaces. In the chemical industry, hydrogen chloride is most often a waste product or by-product of the widely used chlorination of organic compounds in plastics and insecticides. However, HC1 is almost never found in emissions from industrial enterprises, since it is easily washed out of the exhaust gases and is used in the form of hydrochloric acid, from which chlorine has recently been obtained by electrolysis. Increasingly, hydrogen chloride is formed during the combustion of waste chlorine-containing plastics (especially polyvinyl chloride), which makes it necessary to control.[ ...]

In the garden, no matter how small it may be, you always need a ladder, even two - an ordinary side ladder and a smaller ladder. You need a bench for rest, benches for sitting, in the garden, a cart or a wheelbarrow, a set of garden tools, half of which you can make yourself. A small stove is useful for burning waste and garbage.