Description and properties of coal dust. Coal dust What is coal dust called?

Owners of private houses that are heated using solid fuel boilers regularly face the same problem - coal dust accumulates in fuel storage areas. If you do not clean the room, then over time a lot of waste accumulates, so many begin to wonder: is it possible and how to heat a house with coal dust. Experienced stokers say that this is quite possible. Moreover, there are two options for using dusty waste.

The simple method and its disadvantages

A simple way to heat a house using coal dust involves loading it into an already heated boiler. To do this, put dry wood in the firebox, light it, when the combustion process reaches a certain stage, load coarse coal. The fuel should burn well, otherwise, after loading the dust, the fire will simply go out. If you add coal suspension at the final stage this process, then it will smolder for a long time, releasing a sufficient amount of heat.

What are the disadvantages of the described technique? One of them has already been mentioned - If you load dust into the boiler at the wrong time or in too large quantities, combustion will stop, and when trying to re-ignite the fire, you may encounter certain difficulties. However, there is no formula for accurately calculating the required amount of dust. Here you have to focus on the internal volume of the firebox, the maximum draft force in the boiler and many other factors. That is, the required figure can only be determined experimentally.

The second drawback is more serious. The fact is that Coal dust itself is highly explosive. In a settled state, it does not pose a threat, but if the concentration of suspended matter in the air reaches certain values, an explosion is highly likely to occur. Its destructive power will not be so great, but the main danger in such situations comes from the subsequent fire. Owners who are seriously thinking about how to heat a house with coal dust should always remember this property of crushed fuel.

Preparation of a special mixture

It was an attempt to eliminate the fire hazard arising from the use of dry coal dust that led to the emergence of a second method of heating with its help. In this case first prepare a special mixture, somewhat reminiscent of fuel briquettes. There is nothing complicated about this technology and, in principle, anyone can master it at home.

So, to prepare the fuel mixture, take the same amount of coal dust and small sawdust, combine them, add water and mix until a homogeneous mass is obtained. The main secret here is to correctly determine the required amount of water, when adding it, they are guided by the consistency of the mixture. It should resemble too thick plaster, be slightly damp and set into dense lumps during mixing.

How to heat a house with coal dust, or rather with a mixture based on it? To begin with, firewood is loaded into the boiler, completely filling the volume of the firebox. For this purpose It is advisable to select wood with a dense structure, which when burned produces good coals and does not crumble into fine ash. After the firewood has ignited, wait 10-15 minutes so that a suitable temperature regime is established in the internal volume of the boiler. Next, the burning logs are carefully leveled using a poker and the prepared mixture is placed on top in a heap.

Since the coal-sawdust mixture has high humidity, immediately after loading it, the temperature in the boiler will drop sharply. That's why it is necessary to open the full draft, and, if possible, direct a strong flow of air into the lower blower. You can use a regular small fan for this. It is turned off as soon as the combustion process is restored and the temperature slowly rises. At the same time, cover the air duct damper.

A mixture of coal dust and sawdust will not so much burn as actively smolder. This process can last up to 5 hours - it all depends on the air exchange mode in the boiler. Experience shows that the thermal energy released during complete combustion of 15 liters of the mixture is sufficient to heat a house with an area of ​​100-120 square meters. meters for 10-12 hours. Thus, the above procedure will have to be repeated twice a day.

So, if you are seriously thinking about how to heat a house with coal dust, then you have two options. In the first case, you simply pour dust into the boiler, where coarse coal is already burning. In this case, it is very important to determine the optimal amount of pulverized fuel, and also to prevent the dust from becoming suspended, since this is fraught with its explosion with all that it entails. The second method is more complicated - the dust is mixed with sawdust and, gradually adding water, the desired consistency of the mixture is achieved, which is then loaded into the boiler on top of burning firewood. This method requires preliminary preparation, but it is safer and more effective.

INTRODUCTION

1. Chemical and physical properties of coal dust

Dangerous impact of coal mining in the Kemerovo region

Physiological mechanisms that damage organs

Occupational diseases of coal miners

Sanitary standards for coal mining

Means and methods of protection against harmful factor in production

CONCLUSION

Bibliography

INTRODUCTION

Relevance. The rapid development of the coal industry in the Donbass and other regions of the Russian Federation, the introduction new technology and technologies in production require workers, engineers and technicians to have clearer knowledge, careful adherence to occupational hygiene rules and healthy lifestyle standards.

Exposure to dust miners, metro builders, masons, workers in cement, brick, tile, flour mills, sugar factories, road workers, molders, foundry workers, textile workers are exposed confectionery production. When dust particles enter the respiratory tract, they cause inflammation of the tissue of the pulmonary vesicles, which leads to the development of connective tissue in them. Bronchopulmonary diseases of occupational etiology continue to be the most important medical problem in terms of the amount of social damage caused, which is primarily due to insufficient knowledge of the mechanisms of action of fibrogenic dust of mixed composition, as well as the action of combined factors of gases, aerosols, etc.

1. Chemical and physical properties of coal dust

Dust is characterized by a set of properties that determine its behavior in the air, its transformation in the body, and its effect on the body. Of the various properties of industrial dust, the most higher value have a chemical composition, solubility, dispersity, explosiveness, shape, electrical charge, radioactivity.

The most important properties of dust are directly determined by their dispersion, particle shape, good dissolution ability and unique chemical composition. To evaluate dust from a hygienic point of view, the most important characteristic is nothing more than dispersion.

Dust formation in different mines varies and depends on mining and geological conditions, the microstructure of coal, its strength, humidity, conditions of the seam, as well as the method of extracting coal, the mechanisms used, etc. It has been shown that on hard coals the formation of dust is approximately 25% greater than on soft ones. Wet coal produces less dust. More dust is formed on steep seams than on flat ones, which is associated with the descent of coal. Excavation of coal along the cleavage (bedding) produces less dust than excavation against the cleavage. The main operations associated with dust emission are coal mining with a combine, seam cutting with a cutter, manual and jackhammer breaking, loading onto a conveyor, breaking of coal on steep seams with jackhammers, loading coal from a conveyor into trolleys, work roadheader, drilling and blasting operations, mechanical loading of rock, delivery to the shaft by trolleys, unloading of skips.

In terms of dust generation intensity, not all of these operations are equivalent. According to research, 95% of all dust is generated in mines. Of the total amount of dust generated, 60% comes from the operation of machinery, about 20% from blasting in the face, 10% from breaking and 10% from other work. .

The amount of dust suspended in the air also varies in different mines depending on the reasons mentioned above. The highest dust content in the air is usually observed during the operation of combine harvesters; in the absence of dust control means, its concentration can reach several grams per 1 m3 of air. Another most dusty operation is the operation of a shearing machine, a roadheader. Dust concentrations can reach hundreds of milligrams per 1 m3. Air dust content during dry drilling can reach up to 1000 mg/m3. High dust levels are observed during blasting operations. On steeply dipping seams, large dust formation (several thousand milligrams per 1 m3) is observed when coal is lowered to the loading hatch.

Coal dust is generated during the following production operations:

.Coal breaking with combines and blasting operations.

.Drilling holes.

.Loading coal with loading machines.

.Transportation of coal by conveyors.

.Loading at loading and unloading points.

Maximum permissible concentrations of coal dust:

The process of grinding dispersed materials is well described by Rittinger's law ( specific consumption electricity for grinding is directly proportional to the size of the newly formed surface.

Coal dust is well transported by air flow or combustion products. The dust-air mixture forms a very mobile emulsion that has the properties of a liquid and is easily pumped through pipes. IN individual systems dust preparation facilities located directly at the steam generator, the dust concentration in the air mixture is relatively low and is usually |A1= = 0.5 h-1 kg of dust per 1 kg of air (or gases). If there is a central dust plant (CDP), dust is transported from the CPZ bins to the dust bunkers of steam generators at high concentrations (about 30-35 kg of dust/kg of air) through small-section pipelines using transfer pumps, in which the dust is mixed with compressed air having a pressure of 0. 5-1 MPa (5-10 kgf/cm2). Pumping of a highly concentrated dust-air mixture can be carried out over long distances, on the order of several hundred meters.

Factors affecting the explosiveness of coal dust:

1.The explosive concentration of suspended coal dust is from 16 - 96 g/m3 to 2000 g/m3.

2.The yield of volatile substances is 15% or more.

.The size of dust particles is up to 1 mm, the smaller it is, the more dangerous.

The ignition temperature of coal dust is 750 - 850 0 C. The speed of the blast wave is 1000 m/sec. The strongest explosion is at a concentration of 300 - 400 g/m3. When the combine is operating without irrigation, the dust content in the air is 50 g/m3, with blasting and blasting - 300 g/m3. The deposition of coal dust during the operation of a roadheader is 600 g/m3 per day at the face. When the shearer is operating - 900 g/m3 per day. At loading points (transfers) - 100 g/m3 per day. 4. Humidity and ash content - the higher the humidity and ash content of coal, the less explosive the dust is. The dispersion of dust suspended in the air is generally high: up to 40-80% of dust particles have sizes up to 1.3 microns, 15-35% - up to 2.6 microns, 5-20% - up to 4 microns and 3-10% - over 4 microns.

2. Dangerous impact of coal mining in the Kemerovo region

coal dust mining disease

The transition of the coal industry to market relations requires the profitable operation of its enterprises. The basis of such work is high-performance and reliable equipment that corresponds to the mining and geological conditions of the occurrence of coal seams. Many mines in Kuzbass are currently equipped with mechanized treatment complexes of domestic production, in particular, the Yurginsky Machine-Building Plant (KM-138, KM-142, KM-144). However, there is a steady trend towards the use of imported equipment. As a result of these processes, coal mining enterprises have already become dependent on foreign suppliers, whose services are becoming more and more expensive, which has a negative impact on the cost of coal. Approximately the same situation arises with underground transport equipment, especially with belt conveyors. A serious negative consequence of coal growth is a further deterioration of the environment in the Kemerovo region, which is already not the most prosperous region for life. In the Siberian regions (the cities of Omsk, Tomsk, Novosibirsk, Krasnoyarsk, Kemerovo) there are enough conversion engineering plants that can provide coal mining enterprises with highly productive and reliable equipment. It is necessary to reorient these enterprises to produce just such equipment, for example, by acquiring licenses for the production of the required equipment. Considering that domestic technology 3-4 times cheaper than imported ones, the transfer of the coal industry to domestic equipment will help increase its profitability. In addition, this will create thousands of new jobs in the regions of Siberia.

The problem of the impact of coal mining on the environment is not only hushed up, it remains poorly studied. The territory of the Kuznetsk Basin, where the coal basin of the same name is located, is, according to environmentalists, the most neglected area. Meanwhile, the largest cities of the region are concentrated in it - Novokuznetsk, Kemerovo, Prokopyevsk, Belovo, Leninsk-Kuznetsky, Tashtagol, Kiselevsk. The current methods of coal mining and processing in the Kuznetsk coal basin, whose capacity is estimated at 500 billion tons, have led to a significant transformation of the environment. Transformation is associated with catastrophic disturbances when, as a result of anthropogenic impact, the natural landscape, soil cover, and along with it flora and fauna are completely destroyed (due to the formation of quarries and dumps). Plowing of land, felling of forests, fires, construction of access roads, roads, damages the structure of phytocenoses. As a result, not a single river within the Kuznetsk Basin is suitable for drinking, although the water flows from the mountains is environmentally friendly. The situation is aggravated by the fact that the Kuznetsk basin is surrounded by the Shorsky highlands in the south, the Kuznetsk Alatau in the east and the Salair ridge in the west. This leads to the fact that harmful substances do not travel further than the mountain slopes, concentrating exclusively on the territory of Kuzbass.

Scientists see a way out of this situation in carrying out large-scale measures to rehabilitate disturbed areas, which should begin after the completion of the development of a coal mine or mine. The complex of these measures includes restoring land fertility, cleaning rivers, creating forest parks, protective forest belts and recreation areas. Specially protected areas should appear to preserve environmental biodiversity. The goal is to embed mining enterprises into the cultivated landscape and thereby preserve the biological diversity of the region.

3. Physiological mechanisms that damage organs

Among the occupational factors of coal production, the existence of which, their effect on the body and measures to prevent the health problems they cause, every miner should know about, first of all, dust should be mentioned. Along with the impact of coal dust on the respiratory system, it also affects other organs and systems of the body. Thus, coal dust contributes to the occurrence of pustular diseases of the skin of the subcutaneous tissue (boils, felons, abscesses). When dust is swallowed, the digestive tract can also be affected. Dust, irritating the mucous membrane of the eyes, contributes to the development of conjunctivitis and trauma to the cornea.

However, it should be noted that the impact of mixed dusts on the respiratory system has not been sufficiently studied. There is no justification for the possibility of using cytochemical indicators for rapid assessment of the degree of cygotoxicity of dust in alveolar macrophages, as well as for assessing the health status of workers industrial enterprises and the risk of occupational disease. In this regard, the cytochemical characteristics of neutrophils and erythrocytes in peripheral blood are of particular interest. It is known that peripheral blood obtained from a finger is convenient for a wide and multidisciplinary study and its indicators provide sufficient information for judging metabolic changes in the respiratory organs.

Working underground involves significant physical activity, which, combined with elevated temperature the working environment causes a sharp increase in sweating (up to 4 l/day), leading to a deficiency of water-soluble vitamins and minerals.

Energy costs for miners, depending on their professional background and the nature of the work performed, can fluctuate in a wide range of 14,640-20,900 kJ (3500-5000 kcal). The daily diet should contain proteins 110-190 g, fats 120-180 g, carbohydrates 480-620 g. With daily energy expenditure less than 16,700 kJ (4000 kcal), the ratio between proteins, fats and carbohydrates should correspond to the ratio 14:30:56, and with higher energy consumption - 14:35:51.

Probability of occurrence silicosis is reduced by methionine and cysteine. Therefore, the menu of those working under conditions of exposure to silicon compounds must include sources of milk proteins (cheeses), poultry, fish, legumes, etc.

The change in the nature of the clinical course of the disease is largely due to impaired immune reactivity and lipid metabolism.

Therefore, it seems advisable to monitor early immunological and metabolic changes during inhalation of AMR for timely diagnosis and preventive measures. Experimental models make this possible. In this regard, the purpose of the study was a clinical and experimental study of the characteristics of immune reactivity and lipid profile during inhalation of AMR.

The role played by coal dust in mine accidents is increasingly recognized as important, as noted in the paper, which noted that it was first recognized in the UK following a coal mine explosion in Northumberland (Wales) in 1803. However, understanding this role was still imperfect at that time. The subsequent 1844 disaster at Haswell's Durham mines killed 95 people; The famous scientist Michael Faraday was invited to conduct the investigation. And although the report on the accident noted that mine gas (methane) was not the cause, it was only more than 50 years later that Galloway, a professor of mining at Cardiff University, determined that the cause of both this and more serious explosions was mainly coal dust. .

The mechanism of the phenomenon is currently known. It lies in the fact that a relatively weak methane explosion can cause air flow turbulence sufficient to form a cloud of coal dust in the adit. The ignition of the dust, in turn, generates a shock wave that kicks up even more coal dust, eventually leading to a devastating explosion. The paper determined that the majority of 645 similar incidents of coal mine accidents that occurred in Great Britain alone from 1835 to 1850 were caused by dust explosions. Cybulski notes that the number of coal mine accidents worldwide with at least 50 casualties was 135 between 1900 and 1951, or an average of 151. for one accident. According to the same source, due to explosions in US mines, the average number of casualties for the period from 1931 to 1955 was 117 people. in year.

In order to prevent dust explosions in coal mines or ultimately reduce their consequences, the following is necessary: ​​a) prevent initiating explosions by removing methane and eliminating possible ignition sources; b) limit, if possible, the amount of dust in the adit; c) moisten coal dust; d) use inert powder. This inert powder is silicate-free dust, usually limestone. The powder is loaded into a chute suspended from the ceiling of the adit, which is preferable to simply mixing it with coal dust, as was done before. When an explosion occurs, the chute swings and inert powder is scattered, mixing in the air with coal dust. Lime absorbs the heat generated by combustion, and thus the speed of flame propagation is reduced. In addition, lime participates in an endothermic decomposition reaction, which cools the gas. In Fig. Figure 12.1 shows a diagram of the distribution by year of the number of victims from mine accidents that occurred in the UK (accidents with at least 20 victims were taken into account). It is easy to see that the largest accidents occurred in the distant past.

Analyzing the complaints of miners, it can be noted that a high frequency of colds among miners is observed in the initial period of working underground, when the worker’s body, having found itself in unfavorable conditions, has not yet adapted to them. Then, thanks to the compensatory-adaptive mechanisms of the body, colds are observed less frequently, and only in people with an experience of over 31 years, a slight increase in incidence is again observed, which is apparently associated with a decrease in the immunobiological properties of the body at the appropriate age. .

Dust and smoke, as harmful impurities in the air, have become objects of paramount importance in the struggle to maintain the frequency of the air environment, since their presence invariably created tangible inconveniences, and they themselves were most often a consequence of human activity. Dust is tiny solid particles that can remain suspended for some time. Dust is characterized by the chemical composition, size and shape of particles, their density, electrical, magnetic and other properties.

Damage to the mucous membrane of the respiratory tract by dust deposited on it gradually leads to chronic inflammation - “dust bronchitis”, in the development of which the microflora of the respiratory tract also plays an important role. Peribronchial sclerosis characteristic of silicosis, accompanied by deformation of the bronchi, as well as changes physical properties mucus associated with the effect of SiO2 on goblet cells disrupts the normal transport of this mucus along with dust particles and pathogenic microorganisms, promoting further development endobronchitic process. Thus, dust bronchitis is a combined infectious and dust lesion with a predominant role of one or another component. In addition, the development of chronic bronchitis can occur without significant participation of exogenous irritants (due to repeated colds and infectious diseases of the respiratory system), and among the irritants that certainly contribute to this development, non-occupational (primarily smoking) plays an important role. However, the increased prevalence of chronic bronchitis among eggs exposed to various industrial dusts is beyond doubt, and therefore in Kazakhstan this disease is officially classified as an occupational disease (“chronic dust bronchitis”). Under the influence of dust, diseases such as pneumoconiosis, eczema, dermatitis, conjunctivitis, allergies, etc. can occur. The finer the dust, the more dangerous it is for humans. The most dangerous particles for humans are considered to be particles ranging in size from 0.2 to 0.7 microns, which, entering the lungs during breathing, are retained in them and, accumulating, can cause diseases.

Modern scientific and technological progress in the coal industry has significantly influenced the sociological, physiological, psychological, production and economic aspects of miners' work. Working conditions in coal mines are often characterized by unfavorable combinations of temperature and relative humidity of the working environment, the possibility of contamination with harmful gases, high dust formation in all technological processes, lack of daylight, difficulties in organizing hot meals, water supply and sewage disposal underground, and often forced positioning of the body under earth. The operation of mining machines and mechanisms in confined spaces is accompanied by noise and vibration.

4. Occupational diseases of coal miners

Occupational morbidity in the Kemerovo region. remains one of the highest in the Russian Federation, almost 7-8 times higher than the level for the country as a whole; in 2005 it amounted to 10.8 cases ( Russian Federation- 1.6) per 10 thousand workers, 1102 newly identified occupational patients were registered.

The highest occupational morbidity is recorded in Anzhero-Sudzhensk, Osinniki and Prokopyevsk.

The incidence of miners with temporary disability is at an average level compared with the incidence of workers in other industries. The underground group of workers, as a rule, has a higher morbidity rate than the above-ground group of workers in the same mines. When comparing the incidence of miners of individual coal basins one can note a significant difference both in the overall level of morbidity and in its nature; here, to a certain extent, the specificity of sanitary and hygienic working and living conditions is affected, which are determined by many factors (the climatic and geographical zone of the mines, their depth and length, the state of ventilation, water supply, the method of extracting minerals, the quality medical care and etc.).

Miners, primarily working in production and preparation faces, have a very high level of occupational injuries. Miner injury rates have been steadily declining in recent years due to the mechanization of coal mining and greater compliance with safety regulations.

Of the nosological forms, the largest specific gravity(up to 25 - 30%) are occupied by influenza, catarrh of the upper respiratory tract, sore throat, etc., the so-called colds. Their appearance is promoted by cooling the body, getting wet clothes and shoes. One of the first places in the general morbidity of miners is occupied by pustular skin diseases, which is associated with skin contamination with dust, the use of dirty workwear, microtrauma to the skin, and the use of untreated mine water for washing.

The number of acute gastrointestinal diseases and helminthiases among miners is relatively high, which is due to the lack of properly organized underground sewage disposal and cleaning of mine workings in a number of mines, unsatisfactory drinking water supply, eating food directly at the place of work and improper diet.

Among hydraulic mine workers, high morbidity rates were noted for such nosological forms as diseases of the peripheral nervous system and rheumatism. The level of other nosological forms in the general structure of morbidity among miners differs little from the morbidity rates of workers in other industries. Working conditions in mines may cause occupational diseases miners.

Until 2005 in the structure of professional pathology first place was occupied by dust diseases of the respiratory system (31.5%), occupational hearing loss was 24.4%, vibration disease - 17.2%, diseases of joints and muscles - 20.9%. In 2005, changes occurred in the nosological structure of occupational pathology. The first place is occupied by diseases of the joints, tendons and muscles (27.9%), vibration disease accounts for 23%. Compared to 2001-2003, the proportion of respiratory diseases (21.2%) and occupational hearing loss (17.6%) decreased; occupational infectious diseases accounted for 1.5%.

The structure of morbidity with temporary disability is dominated by three nosological groups: diseases of the respiratory system, musculoskeletal system and injuries (up to 55% of all causes of temporary disability).

Analysis of the distribution of occupational diseases by industry in the Kemerovo region. showed that for 2003-2005. 77.8% of occupational patients are from the coal industry. Basically, these are people employed in underground mining operations Oh. In non-ferrous and ferrous metallurgy - 5.7% of professional patients, in mechanical engineering, metalworking and electrical industry - 4.7%, in construction - 2%, the share agro-industrial complex accounts for 1.9%, in healthcare - 1.4%. This structure has essentially remained unchanged over the past 5-6 years. Thus, it is confirmed that the coal industry of Kuzbass has the highest occupational morbidity rate

Of the factors in the working environment, the most significant for occupational risk are: noise, vibration, coal-rock aerosols, toxic substances (carbon monoxide, nitrogen dioxide) . The impact of noise and vibration on workers is due to the imperfection of mining equipment. So, according to the results of measurements on coal mines In Novokuznetsk, noise levels at the workplaces of excavator drivers exceed the maximum permissible level by 4 dB, general vibration - by 4 dB, local vibration levels are higher than the required values ​​- by 1-2 dB. At the workplaces of drilling rig operators, the levels of sound pressure and general vibration exceed the maximum permissible by 3 dB. In the driver's cabins of heavy-duty vehicles, noise levels are 2-4 dB above the maximum limit, and overall vibration exceeds the maximum limit by 6 dB.

When operating mining and transport equipment, in addition to noise and vibration, workers are adversely affected by heaviness and tension. labor process, characterized by physical overstrain of the muscles of the arms, shoulder girdle, and body, as a result of which pathology of the musculoskeletal system develops. An aggravating factor in the development of occupational diseases is a 12-hour work shift. The risk group for the development of occupational pathology includes such professions as excavator and bulldozer operators, drilling rig operators, and heavy truck drivers. The working conditions of these professions are characterized as hazardous, class 3. Exposure to dust miners, metro builders, masons, workers in cement, brick, tile, flour mills, sugar factories, road workers, molders, foundry workers, textile workers, and confectionery workers are exposed. When dust particles enter the respiratory tract, they cause inflammation of the tissue of the pulmonary vesicles, which leads to the development of connective tissue in them. Bronchopulmonary diseases of occupational etiology continue to be the most important medical problem in terms of the amount of social damage caused, which is primarily due to insufficient knowledge of the mechanisms of action of fibrogenic dust of mixed composition, as well as the action of combined factors of gases, aerosols, etc.

Coniotuberculosis occurs among coal workers much less frequently than among mining workers, and its course is much more favorable.

The prevalence of pneumoconiosis among coal industry workers is decreasing every year. In 1963-1964. in the Donetsk basin, during annual medical examinations, less than 1% of those examined were found to be ill. Pneumoconiosis in miners of the Donetsk basin is detected with an average dust exposure of 8-10 years.

Coal dust is assessed from two points of view: sanitary and hygienic and safety. The sanitary and hygienic significance of coal dust is determined by the changes that it causes in the respiratory system. The main place among them is pneumoconiosis. The most important role in protecting the body from harmful effects factors of the production environment belongs to nonspecific protection, its basal main link, namely, phagocytosis carried out by alveolar macrophages of the lungs and blood neutrophils. In the development of protective and adaptive mechanisms that arise in the body at the early stages of the pathological process, an important role belongs to the earliest metabolic reactions occurring at the cellular and subcellular levels.

A dust explosion is an object of intensive study, to which numerous works and individual monographs are devoted. It can be considered in two distinct aspects: dust explosions in adits and dust explosions in equipment and inside buildings. The former are characterized by a shock wave propagating along the adit, the length of which can reach several kilometers. Although the description of dust explosions in coal mines does not correspond to the main topic of this work.

This reduces the respiratory capacity of the lungs and disrupts gas exchange; Along with this, keratinization of the epithelium of the airways occurs, which reduces its ability to retain dust particles. Consequently, with systematic exposure to dust, the supply of oxygen to the body through the lung tissue deteriorates and the barrier function of the respiratory tract decreases, and occupational diseases develop, such as silicosis, which occurs under the influence of quartz dust. It is known that prolonged exposure to any damaging factor leads to disruption of enzyme systems and metabolism occurring in cells, which are classified as nonspecific protective factors. In recent years, factual material has been accumulated that suggests that changes in the functional and metabolic activity of blood leukocytes can act as sensitive indicators of homeostasis disturbances in the respiratory organs during early protective and adaptive reactions. According to the opinion, quantitative and qualitative changes in blood elements, namely a decrease in the functional activity of leukocytes, an increase in the level of destruction, reflect the initial phenomena of decompensation. .

The leading forms of occupational diseases are silicosis, anthracosis and dust bronchitis, vibration disease, diseases of the musculoskeletal system, auditory neuritis and bursitis. As evidenced by data from the Research Institute of Occupational Hygiene and Occupational Diseases of the USSR Academy of Medical Sciences [Vorontsova E.I., 1984], as a result of the introduction of health-improving measures of a social, engineering, technical and therapeutic-prophylactic nature, the level of occupational respiratory diseases is steadily decreasing. Thus, during the period from 1975 to 1980, the incidence rate of pneumoconiosis in the coal industry decreased by more than half. The forms of pneumoconiosis depend on the nature of the coal, in particular on its strength and ash content, the percentage of silicon dioxide in coal and rocks, as well as on the length of work in mines and work with coal or rock and the degree of dust in the air. The predominant type of pneumoconiosis in miners is stage I anthracosilicosis. It is registered among workers with 15 - 20 years of underground work experience. Chronic dust bronchitis is becoming increasingly important in the professional pathology of miners. In addition to industrial dust, factors predisposing to the development of chronic dust bronchitis are a cooling microclimate, pollution of the mine atmosphere with irritating gases, frequent acute respiratory diseases, and smoking.

Vibration disease ranks second after pneumoconiosis among the occupational diseases of miners. It can occur in miners who are constantly working with jackhammers and drilling hammers. Moments that aggravate the harmful effects of vibration are muscle overstrain, forced working posture, cooling of the hands and the whole body, which can be observed in water-rich mines, especially with low temperatures air and developed soil. Among miners who work for a long time in conditions of intense noise (100 dB and above), cases of auditory neuritis and other symptoms of noise pathology have been recorded.

Among the occupational diseases of the musculoskeletal system among miners, the leading place belongs to bursitis.

5. Sanitary and hygienic standards for coal mining

Microclimate parameters, levels physical factors(noise, vibration, ultra- and infrasound, electromagnetic fields), the content of dust and harmful substances in the air of the working area must comply with hygienic standards. The leading harmful factors in the mining and processing of coal (oil shale), leading to the development of severe occupational diseases, are high dust levels, intense noise and vibration, high severity and intensity of labor, most pronounced in underground mining.

For all technological processes requiring the use of water for dust suppression, and for sanitary services workers use water that meets bacteriological and sanitary-hygienic indicators, hygienic requirements for water quality centralized systems drinking water supply.

For dust suppression purposes, it is prohibited to use mine and other waters to supply water to sprinklers, foggers, drilling and loading machines if the concentration of radon or thoron in them exceeds curie/l. If there are no other sources of water supply, then to use waters containing emanations in large quantities, measures are taken to de-emanate them.

The use of surfactants (hereinafter referred to as surfactants) to bind settled dust is possible only by mechanized means. Workers who have direct contact with highly concentrated surfactant solutions polymer materials, reagents and antifreezes used for heat, hydro and gas insulation, prevention of sudden emissions and strengthening of mountain ranges, as well as means for treating coal against freezing and weathering, are provided with protective waterproof clothing and footwear, goggles, respirators, rubber gloves.

During development technological processes and design of equipment, maximum mechanization of repair, installation and dismantling is provided and measures are provided to reduce the levels of factors working environment and the labor process when performing these works.

Operation and repair of devices with sources of ionizing radiation, radiation monitoring and registration of its results are carried out in accordance with the requirements for ensuring radiation safety.

Requirements for the conduct of work and for the premises in which mercury-filled instruments, devices, apparatus are installed must comply with the provisions sanitary rules when working with mercury.

The use and maintenance of lasers is carried out in compliance with hygienic requirements for their design and operation.

The employer provides workers with special clothing, safety shoes and equipment personal protection(hereinafter referred to as PPE), flushing and disinfecting preparations and organizes their proper storage, use, cleaning, washing, repair, disinfection and other types of preventive treatment.

In coal mining and processing organizations, production control in accordance with hygienic requirements to organizations engaged in mining and processing of coal (oil shale). The employer is obliged to provide information to the bodies authorized to carry out state sanitary and epidemiological supervision on the severity of factors in the working environment, the sanitary state of atmospheric air, water bodies, soil, solid industrial waste and the compliance of the technology used with the approved project.

In Russia, standards in the field of various harmful factors have been developed and put into effect long ago. Many countries have laws and federal programs Between the reclamation of the area and then carrying out mining operations, technologies have been developed for filling the mined-out space with household and construction waste. If mining regulations or safety requirements are not followed during mining operations, undesirable consequences such as underground fires, fires in dumps, pollution of watersheds with water containing acids, metals or suspended solids, and in addition landslides are possible unstable slopes. In many countries, including the USA, there is a series of laws that cover all aspects of development coal deposits and providing for the implementation of continuous monitoring during mining operations, eliminating the possibility of undesirable environmental consequences. .

The presence of substances with toxic properties in dust increases its danger. Dust concentration in real production conditions can range from several mg/m3 to hundreds of mg/m3. GOST 12.1.005-88 “General sanitary and hygienic requirements for the air of the working area” establishes maximum permissible concentrations (MAC) of dust in the air of the working area.

6. Means and methods of protection against harmful factors at work

Prevention and prevention measures: dust control measures are determined by the nature of production. In order to reduce the harmful effects of dust on workers, if the maximum permissible concentration is exceeded, work time is limited, personal protective equipment is used, local and general ventilation is used, and constant wet cleaning of premises is used.

Measures to combat the formation of coal dust:

1.Moistening of coal seams (preliminary injection of water into the seam).

2.Irrigation, pneumatic hydroirrigation.

.Water curtains.

.Water-air ejectors.

.Hydrojet sprayers.

.Dust collection (dust extractors, construction of casings on embankments, fabric partitions)

.Dust-removing ventilation

.Sharp cutting tool.

Measures to prevent coal dust explosion:

1.Rinse, moisturize.

2.Serging.

.Whitewashing: lime-cement mortar; 1 part cement, 2 parts lime, 30 parts water.

.Water curtains, foggers.

.Oslanization.

.Shale or water barriers.

.Drinking water, or from treatment facilities.

Wellness activities. Reduced dust levels; heating the air supplied to the mine in cold period of the year; eliminating seepage and accumulation of water in places where workers stay and move; installation of heated chambers in the courtyards near the shaft for miners waiting to rise; installation of rational welfare facilities with dressing rooms, showers, installations for storage, dust removal, drying, washing and repair of work clothes, daily sanitation of microtraumas, washing of safety shoes, ultraviolet irradiation of workers. In coal mines - the installation of mobile heated rooms to warm workers in the cold season, insulation of the cabins of excavators, bulldozers and dump trucks, timely delivery of the necessary protective clothing and footwear.

In order to prevent occupational diseases in the coal industry, mandatory pre-employment and periodic medical examinations have been introduced. Those working in tunneling and clearing operations are subject to a medical examination once every 12 months, other mine workers - once every 24 months. There is a wide network of dispensaries equipped with the necessary equipment for physiotherapeutic procedures, therapeutic exercises, and diet. Recently, the so-called comprehensive mechanization of coal mining has been widely introduced, based on the use of powerful coal miners, metal shields and powered roof supports, which will make it possible to switch to remote control units.

Protection of miners from the harmful effects of dust includes:

air dust removal;

organization of ventilation of mine workings;

measures to combat dust in the air entering the mine from the surface;

providing miners with personal protective equipment against dust (filtering respirators). Plays a major role in the prevention of occupational dust diseases healthy image life, giving up bad habits, adequate sleep, balanced nutrition, exercise, breathing exercises. .

CONCLUSION

Coal industry is a branch of industry for the extraction of hard coal from its deposits in the earth's crust. There are two methods of coal mining: closed (in mines) and open (in open pits, quarries).

The main work in mines is: cutting the seam using cutters, breaking coal using explosives, pneumatic jackhammers, combines, “mechanized” complexes or hydraulically. Coal is transported from the longwalls by conveyors to the haulage drift and delivered to the shaft by electric locomotives for delivery to the surface.

In open-pit mines, the coal seam is loosened using the drilling and blasting method, the coal is loaded onto dump trucks and transported to the surface.

Leading professions in underground work: tunnelers, drillers, blasters, bulk breakers, riggers, combine and cutter operators. In most mines they are organized into complex teams with wide interchangeability. The leading professions in the quarries are drillers, blasters, excavator and electric locomotive drivers, bulldozer and dump truck drivers.

Occupational hazards in the coal industry: unfavorable meteorological conditions, emission of dust (see) and harmful gases, noise (see), vibration (see), forced body position on gently sloping thin seams, in hydraulic mines there is a danger of eye injuries (for hydraulic monitor workers).

Almost all coal mines contain methane, carbon dioxide, carbon monoxide, sulfur dioxide and nitrogen oxides.

Dust in the air of mines and open pit mines consists of coal and rock particles. The mineral content in it ranges from 15 to 40%, free silicon dioxide - from 1 to 10%. According to Sanitary Standards SN 245-71, the maximum permissible concentration of coal dust in the air of workings should not exceed 10 mg/m3 - when the free silicon dioxide content in coal is up to 2% and 4 mg/m3 - when its content is more than 2%. However, dust content in the air often exceeds this value many times, especially when harvesters are operating. To reduce dust formation during coal mining, the following are used: 1) injecting water into the coal seam before extracting coal from it; 2) spray irrigation with water in places of greatest dust formation; 3) dry dust collection from coal mining sites using special devices of a combine or “mechanized complex”.

Occupational injuries are always higher among workers in the face group. The most common reasons are violations of safety regulations during mining and coal transportation.

Occupational diseases: silicosis, silicic anthracosis, anthracosilicosis; observed among workers in rock and coal faces with an average of 15-20 years of work experience. Bursitis (see) occurs in those working on gently sloping seams, vibration disease - in combine operators working in mines with steep seams and in drillers.

Pustular skin diseases and colds, myositis, neuritis, radiculitis are more common among workers in cold, damp coalfaces, when working in an uncomfortable position and under great physical stress.

Bibliography

1. T.A. Hwang, P.A. Hwang. Fundamentals of ecology. Series "Textbooks and teaching aids". - Rostov n/d: "Phoenix", 2001. - 256 p.

Belov S.V. Life safety - 1999 - 449 p.

O.E. Falova. Physiology of the respiratory system - 2006 - 124 p.

Life safety: Tutorial. Part 2 / E.A. Rezchikov, V.B. Nosov, E.P. Pyshkina, E.G. Shcherbak, N.S. Chvertkin / Edited by E.A. Rezchikova. - M.: MGIU, - 1998.

5. Golubev E.I.. Cleaning works. - M: Medicine, 1998.

6. Ecology and life safety: textbook. manual for universities / D.A. Krivoshein, L.A. Ant, N.N. Roeva and others; Ed. L.A. Ant. - M.: UNITY-DANA, 2000. - 447 p.

Similar works to - Coal dust. Physiological mechanisms of damaging effects on the body

E.A. Elchanov and A.I. Shor studied the consequences of snow pollution by coal dust in the permafrost zone. Its increased amount near mines and quarries in the permafrost zone is due to the fact that frozen coals are more fragile, and this causes increased dust formation during their breaking. A large amount of coal dust is carried out of the mines by ventilation jets, and even greater spread of dust occurs when frozen coal is loaded into vehicles on the surface. As a result, the area around the mine within a radius of 15-20 km is clogged with coal dust. The snow cover melts here earlier than usual, and the depth of soil thawing increases by 2.5-3 times compared to the norm. All this causes the formation of lakes and increased swampiness of the territory. Due to the removal of dust, the water in lakes in the spring contains up to 30-60 g/l of suspended particles and is completely unsuitable for water supply to the population. Pollution of surface waters leads to the destruction of zoocenosis over an area significantly larger than the size of the aeolian dispersion of coal dust. Such a disruption of the natural cycle of matter ultimately causes very severe degradation of the landscape.[...]

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Coal dust is deposited in a person's lungs with such strength that it is easy to determine a person's profession by just the type of lungs. Coal dust promotes the development of coniosis. Fine quartz dust, present in the air of ore mines, processing plants and some other industries, leads to a person developing silicosis.[...]

The coal industry is a leader in the emission of solids and sulfur oxides into the atmosphere. However, the absolute emission of solid substances in 1996 in the coal industry amounted to 76.95 thousand tons. However, when assessing the environmental consequences of the use of coal in Russia, the work indicates “colossal emissions of coal dust and, in particular, during coal transport.” The emission of coal dust is 15 kg/tce, and the entrainment of dust during transport gives 3-6 kg/tce. Based on the production of 1 million tons of equivalent fuel. coal, such emissions of coal dust will amount to 15 thousand tons. and dust removal during transport is 3-6 thousand tons [...]

The supply of coal dust to the boiler furnace is regulated in accordance with the required steam output. The supply of limestone is regulated taking into account the sulfur content in the fuel according to the ratio Ca/8.[...]

Table 2 for the coal industry shows the specific emission of coal dust (15,000 tons) by .[...]

The pathogenic composition of dust depends on the content of free silicon dioxide in it. Coal dust with a high content in the air (about 100 g/m3) is explosive.[...]

In cyclone 2 coal dust is retained. It goes down into the unloading pipe, at the lower and upper ends of which there are cone valves.[...]

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The third category is flammable dust, which can explode at concentrations above 65 g/m3. This includes tobacco, zinc, and coal dust.[...]

From the cyclone, after rough cleaning of coal dust, the generator gas goes through a gas pipeline into special retort furnaces and burns in them. In the gas generator shaft 1 and bowl 6, from the bottom of the bowl to a level 200 mm above the grate 4, there is ash; above, for 1000 mm to the lower end of the drain pipe suspended under the loading box, lies charcoal.[ ...]

The determination does not interfere with iron, aluminum, coal dust, silicate dust containing aluminum and iron, quartz, tin and antimony.[...]

Coke production pollutes the air with coal dust and soot. The sources of these revenues are the following production processes: grinding coal, loading the charge into the chambers of the coke oven battery, unloading coke into the quenching car.[...]

In most cases, a mixture of coal dust and ground limestone was fed into the burners. In the furnace, when burning coal dust, limestone - calcium carbonate - dissociates into carbon dioxide and calcium oxide, and the latter, moving together with the combustion products through the flues of the boiler, interacts with sulfur and sulfur dioxide, forming calcium sulfite and calcium sulfate. Calcium sulfate and sulfite along with ash are collected in ash collectors. Free calcium oxide contained in fuel ash also binds sulfur oxides. The main disadvantage of this method of gas purification is the formation of durable deposits of ash and calcium sulfate on heating surfaces in the temperature range of 700-1000° C. [...]

Experiments were carried out with waters contaminated with sand, coal dust, scale or lime silt, in order to determine the magnitude of excess pressure and swirl speed necessary to obtain optimal coefficients useful action hydrocyclones and thickening. After numerous experiments, hydrocyclones with an internal diameter of 200-300 mm were designed, when purifying with excess atmospheric pressure from waters of the sugar industry, waters contaminated with fly ash of heating plants and washing scale of hot rolling plants, the purification coefficient was 94-96%. It has been established that a hydrocyclone is not suitable for treating paper industry wastewater contaminated with fiber. Particular importance was attached in BNR1 to experiments aimed at developing new methods for using activated sludge for the purification of municipal or non-industrial wastewater. On larger installations working with clarified water, with a passage time of 40 minutes. the purification coefficient in terms of BODco was 91.8% and those working on the original wastewater when passing through for 1 hour - 86.3%.[...]

Polyurethane foam, coal dust, crumb rubber, sawdust, pumice, peat, peat moss, etc. They even use straw, which, depending on the type of oil, adsorbs it in an amount that is 8 to 30 times its weight. They use a spongy material made of polyurethane foam, which absorbs oil well and continues to float after adsorption. According to calculations, 1 m3 of polyurethane open-cell foam can sorb about 700 kg of oil from the surface of the water.[...]

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Noteworthy is the device for preparing a coal suspension, proposed by V. S. Besan. This device consists of a conical funnel, which is equipped with four nozzles connected to a pressure pipe. The nozzles are located in such a way that the stream of water emerging from them moves along the conical part of the funnel in a spiral manner from top to bottom, capturing pulverized coal continuously entering the funnel. A conical visor is provided above the outlet of the device to prevent coal dust from clumping in water. In order to impart rectilinear movement to the resulting coal suspension, a guide pipe is installed at the outlet of the device.[...]

Fumming is the blowing of a molten slag bath with a mixture of coal dust and air through the tuyeres of periodically operating rectangular slag distillation furnaces. Their hearth dimensions are: width up to 2.5, length up to 10 and height up to 9m. At 1250-1300°C, the oxides of lead and zinc are reduced, and the vapors of these metals sublime. Above the bath and in the flue they are oxidized by residual oxygen from the blast and are carried away in the form of fine dust containing 15-25 and 60-75% lead and zinc, respectively. It is processed in zinc production. Coal consumption is about 20% of the slag mass. The latter after fuming is dump.[...]

According to research by Soviet doctors (Chizhevsky, Sokolov), air polluted with dust, particles of coal dust and acids from factories and factories weakens the human body: causes high blood pressure, drowsiness, a feeling of weakness, headaches. [...]

Wastewater from lignite briquette factories, resulting from the deposition of coal dust wet method, have a temperature of about 40-60 ° C, are very cloudy and dark brown in color. The deposited coal dust particles are very light (specific gravity less than or only slightly more than 1.0), greasy to the touch (due to the bitumen they contain) and therefore only difficult to mix with water. Initially, coal dust particles tend to float and settle only after they have absorbed a sufficient amount of water, i.e. after several weeks or even months.[...]

In work, the sludge is alkalized with Ca(OH)2 to pH = 8.5-14.0, mixed with 10-60% (may.) iron sulfate grinding dust and 10% (may.) copper sulfate, add sawdust and coal dust or peat in the amount necessary to obtain a granular mass, and burn at 800-2000 °C. Heat treatment electroplating sludge is a passive way to solve the problem. Please note that burning sludge leads to air pollution and damages environment. It is necessary to develop technologies that would allow the use of valuable chemical components of sludge and completely prevent environmental damage.[...]

In Fig. 35 shows a diagram of an installation adapted by the Lurgi company for burning liquor with coal dust.[...]

When grinding coal, loading charge into batteries and unloading coke at coke production plants, coal dust and soot are formed. During the coking process, a gas containing vapors of hydrocarbons (resinous substances) is released. The amount of gaseous emissions is 3-5 m3, tarry substances 0.2-0.5 kg per 1 ton of coal used.[...]

Fuses are formed as a result of enveloping a volatile solid phase (coal, shale, peat dust) with resin contained in a vapor-gas mixture during thermal processing of solid fuel in coking chambers or gas generators. When coking coal, for example, slurries are deposited during the settling of the gas phase condensate (due to the difference in their density from the density of tar water and resin), they are periodically removed from the decanter. At low temperatures, fuses harden into a brittle material. Due to the partial dissolution of coal dust or components of pulverized shale (peat) in the resin and the physical state of the resulting materials, the separation of fuses into components is a difficult task for practical implementation.[...]

A special feature of the UVV series electric precipitators is that, due to the possible occurrence of an explosion hazard when coal dust accumulates, the casings of the electrostatic precipitators are made in the form of a shaft open to the atmosphere. This prevents the case from being destroyed by “popping”. In addition, all internal devices of electrostatic precipitators are designed in such a way as to avoid dust accumulation. This is achieved by not including horizontal platforms or covering them with beveled canopies, as well as by constructing bunker walls with large slope angles.[...]

Wastewater generated from watering lump chamotte before crushing, from washing quartzite, wet air cleaning from dust, washing scrubbers of ventilation units, cutting table during plastic molding (in old factories), washing off the floors of the coal grinding department, is contaminated only with mechanical impurities - clay, chamotte , quartzite, magnesite, chromium-magnesite and coal dust. Magnesite and chromium-nickel dust have a crystalline structure; the content of suspended substances in wastewater reaches 20-60 g/l. Fireclay dust contains a significant portion of dispersed clay particles, the concentration of suspended substances in wastewater is 15-23 g! l. Clay dust is predominantly finely dispersed; the content of suspended solids in wastewater is 3.5-21 g!l. The estimated content of suspended solids in the total runoff of polluted waters can be taken as 30-50 g/l. Water purified in settling tanks is used for circulation. In addition to the above, there are acidic waters from washing refractory powders, containing hydrochloric acid up to 5 g/l and dissolved impurities - iron, beryllium, zirconium, magnesium, etc. This water is neutralized with lime and clarified in settling tanks, and beryllium water due to the fineness of the suspension pre-filtered. Effluents from laboratories are also acidic.[...]

Electrostatic precipitators of the UVV series (Fig. 1.102) are unified vertical plate dry electrostatic precipitators for collecting coal dust from gases at temperatures up to 130 “C. Just like in electric precipitators of the UV series, the main elements are unified with the corresponding elements of electrostatic precipitators of the UG series. Since coal dust shakes well, the shaking mechanisms of the UVV series electric precipitators are lightweight.[...]

Currently, another TPP-312 boiler is being reconstructed at the Ladyzhinskaya State District Power Plant according to the same scheme, using finer ground coal dust for the reburning process.[...]

Polycyclic organic compounds, the main sources of which are coal and wood stoves, coal dust when burned, and coke production, may predispose to lung cancer. They account for more than 90% of the contamination with polycyclic substances.[...]

Compound different types fuses,%: 30-70 substances insoluble in toluene, 20-60 resins, 2-7 ash, 3-10 water. Substances insoluble in toluene (or benzene) are coal dust of varying degrees of thermal destruction and sedimentation, as well as resinous particles formed as a result of coagulation of high-molecular multi-ring compounds. These substances are often called free carbon. The yield of volatile substances from it is 9-17%, and from fuses - 30-65% in relation to their dry weight. The granulometric composition of the latter varies widely - from 63% class[...]

In London, the number of fogs and their intensity increased in parallel with the growth of factories and factories. 225-380 g of soot falls on 1 km 1 of London. Human lungs from coal dust lose their pink natural color and become slate-gray.[...]

A second long-term hazard to miner health that is currently of particular concern in the United States is the high levels of coal dust in the air. Conventional coal mining machines seem to bite into the coal seam with teeth located on a rotating drum. In this case, pieces of coal are crushed and a huge amount of fine dust is formed, which is extremely difficult to get rid of. The safe concentration of such dust particles is set by the federal government at 2 mg/m3. Conventional coal mining machines, not equipped with special dust collectors, create dust concentrations of about 20 mg/m3, and often when operating at full capacity permissible level dust limits set by the US federal government are exceeded. At the same time, during hydraulic coal mining, as measurements have shown, the dust level is only about 0.15 mg/m3, which is much lower than the established norm and, therefore, ensures greater safety for workers.[...]

Let us also note other properties of aerosols that directly threaten health and life - their explosiveness and possible spontaneous combustion. We have already noted these properties of aerusols in relation to coal dust (Lotosh. They are also inherent in other types of them. These include, for example, fine dusts of iron, aluminum, zinc. The explosion hazard and spontaneous combustion of dusts depend on their chemical composition, concentration and dispersion.[ ...]

Thus, an ideal example of wood pyrolysis in a gaseous environment is the pyrolysis of wood flour in a fluidized bed, in which each particle is washed on all sides by a coolant. But at the same time, it is difficult to combat the entrainment of coal dust particles and capture vapors of valuable products when they are very diluted with non-condensable gases. The amount of loss of valuable products may exceed their additional yields. [...]

In Kopeisk Chelyabinsk region planned to build thermal power plant with a circulating fluidized bed.[...]

In Uzbekistan, humic preparations developed at the Institute of Chemistry of the Academy of Sciences of the Uzbek SSR based on the use of local coals turned out to be very highly effective. The drugs in this group include the following. It has the appearance of coal dust with a faint odor of ammonia. Contains 3.6% nitrogen and 30-40% humic acids. Humophos is an ammoniated mixture of weathered Kizyl-Kaya coal and superphosphate in a 1:1 ratio. Contains 2% nitrogen, 9-10 humic acids and 10-12% plant-available phosphorus. GU-VU is a new humic fertilizer made from weathered coal in the form of initial coal dust or granules. Contains 30% humic acid. HA - humic acid, isolated from the same coals. The main active principle of carbon-humic fertilizers is humic acids.[...]

The ventilation exhaust stream freed from SBD is sent for cleaning from entrained coal dust particles into cyclones and then released into the atmosphere. The captured coal dust is returned by the auger to the adsorber.[...]

The gas containing SC>2 is treated with an absorption solution containing magnesium oxide, resulting in the formation of magnesium sulfite. After this, the absorbent containing magnesium sulfite is mixed with a carbon-containing substance. The resulting mixture is heated (200 - 400°C) in a regeneration apparatus to release concentrated SO2 (more than 10%) for subsequent processing into sulfuric acid, and magnesium oxide is returned to the process. In order to reduce the cost of the process, coal dust or a mixture of carbon monoxide and hydrogen is used as a carbon-containing substance.[...]

During hydrotransport of the adsorbent, mixing of the dispersed and continuous phases is ensured by turbulent pulsations of the flow. To intensify the mixing process and accelerate the absorption of dissolved substances by active carbons, special inserts or devices 5 are often installed in pipelines, causing additional development of turbulence in the flow when the fluid speed changes in magnitude and direction. They are made in the form of cones, lattices, alternating vertical partitions of various configurations, and helical twisted elements. Waste water that has undergone purification is subjected to partial clarification from suspended coal in settling tanks or open multi-tier hydrocyclones 6. Waste coal retained in settling tanks is sent through slurry pipeline 7 for regeneration. The final release of purified water from coal dust is carried out using rapid coarse filters 8.[...]

Another type of electrical detection consists of recording selected characteristic mass lines of elements by automatically switching the voltage magnetic field or accelerating and focusing voltages. In this case, the ion current corresponding to each selected type of ion is integrated over a significantly longer period of time, which makes it possible to “smooth out” the instability of the ion current of the discharge source and reduce the influence of sample heterogeneity on the analysis results. An increase in the registration time also causes a significant increase in the sensitivity of this detection method compared to that in the method of sequential scanning of all mass lines. The use of selected ion detection techniques in the analysis of samples containing unknown elements is associated with significant difficulties, which is a significant drawback of this method. However, electrical detection, by reducing the time required for analysis, makes the IC method suitable for routine use, allowing studies to be carried out at relatively low resolution. Due to this, spark mass spectrometry is used to determine the elemental composition of trace contamination in coal dust aerosols and coal gasification products.

Coal dust is generated during the following production operations:

1. Coal breaking with combines and blasting operations.
2. Drilling holes.
3. Loading coal with loading machines.
4. Transportation of coal by conveyors.
5. Loading at loading and unloading points.

Maximum permissible concentrations coal dust:

Factors affecting the explosiveness of coal dust:

1. Explosive concentration of suspended coal dust
   from 16 - 96g/m3 to 2000 g/m3.
2. The yield of volatile substances is 15% or more.
3. The size of dust particles is up to 1 mm, the smaller it is, the more dangerous.

The ignition temperature of coal dust is 750 - 850 0 C.
Blast wave speed 1000 m/sec.
The strongest explosion at a concentration of 300 - 400 g/m3,
When the combine is operating without irrigation, the air dust content is
50 g/m3, with blast-blasting - 300 g/m3.
The deposition of coal dust during the operation of a roadheader is 600 g/m3 per day at the face.
When the shearer is operating - 900 g/m3 per day.
At loading points (transfers) - 100 g/m3 per day.
4. Humidity and ash content - the higher the humidity and ash content of coal, the less explosive the dust is.

Measures against education coal dust:

1. Moistening of coal seams (preliminary injection of water into the seam).
2. Irrigation, pneumatic hydroirrigation.
3. Water curtains.
4. Water-air ejectors.
5. Hydrojet sprayers.
6. Dust collection (dust extractors, construction of casings on embankments, fabric partitions)
7. Dust-removing ventilation
8. Sharp cutting tool.

Explosion Prevention Measures coal dust

1. Rinse, moisturize.
2. Serging.
3. Whitewashing: lime-cement mortar; 1 part cement, 2 parts lime, 30 parts water.
4. Water curtains, foggers.
5. Oslanization.
6. Shale or water barriers.
7. Drinking water, or from treatment facilities.

Localization of explosions methane gas and coal dust

Screens.

Designed to localize (prevent the spread of) methane explosions
and coal dust.

SHALE– shelves - trapezoidal support. Width 250-500 mm.
The distance between the shelves is equal to the width of the shelf.
There are small sides - 5 cm. Inert dust is filled in -
(from slate, dolomite, shell rock)
The shelves are filled at the rate of 400 kg per 1 m2 of cross section
workings, the length of the barrier is at least 20 m.
The first barrier is installed no closer than 60m from the face,
subsequent ones - no further than 300m.

WATER– vessels with a capacity of more than 80 liters, trapezoidal cross-section 150 x 300 x 250
The amount of water and vessels at the rate of 400 liters per 1 m2 of cross-sectional area of ​​the excavation, length 30 m installation - no closer than 75 m,
Subsequent ones no further - 250m.

Automatic system explosion suppression - explosion localization (ASVP-LV)

Organic dust in most cases, pneumoconiosis itself does not cause. The cases of coniosis caused by certain organic dusts described in the literature, upon a more careful analysis of the symptomatology, often turn out to be not coniosis, but other forms of lung disease. From all types of organic dusts highest value has coal dust. Lung fibrosis observed in anthracosilicosis is not caused by coal, but, as mentioned above, by the mineral dust contained in it as an admixture, which includes quartz and silicates.

Admixture of mineral particles in coal dust can be quite significant; Thus, in brown coals it reaches 25-30%. It is quite difficult to distinguish coal dust particles from mineral particles under a microscope, since the large black coal particles cover the colorless mineral particles. The opinion that pulmonary fibrosis in these cases is caused by mineral dust is confirmed by the fact that an increased amount of silica is chemically determined in the lung tissue of workers who inhaled coal dust mixed with mineral dust.

However research recent years conducted by the Institute of Occupational Physiology (Rabbi et al.) indicate the possibility of developing pulmonary fibrosis under the influence of inhalation of pure coal dust containing neither quartz nor silicates. These fibroses are benign.

Dust and pneumonia. Penetration of dust into the alveoli may be accompanied by the formation of inflammatory exudate in them. This exudate, in the presence of sufficiently virulent pathogenic microbes, can spread to a more or less extensive area of ​​lung tissue and give the clinical picture of lobar, or lobular, pneumonia. These acute dust pneumonias are possible primarily in workers engaged in grinding the so-called Thomas slag, a by-product of steel production.

The latter thanks to great content of phosphorus salts is a valuable artificial fertilizer. To make the slag suitable for consumption, it is ground into powder. During the period when grinding of Thomas slag was introduced at factories, workers, according to foreign authors, often experienced severe pneumonia and a large percentage mortality, and the mortality rate from pneumonia among workers engaged in grinding Thomas slag was 30-60 times higher than among the rest of the population of the same age.

Form in question pneumonia most often refers to lobar. Its outcome in cases ending in recovery may be severe emphysema. In addition to Thomas slag, pneumonia is caused by dust from manganese ore (brown iron ore) and potassium dichromate. In Russia, these pneumonias are rare.

Along with the dust lungs Spores of various fungi can be introduced - molds, radiata, etc., which leads to the development of so-called pneumomycosis. The most common infection is with species of the genus Aspergillus. Flour millers, agricultural workers, brewery workers, workers dealing with animal hair, etc. are susceptible to infection of the lungs with fungi. The disease occurs either in the form of pneumonia or in the form of bronchitis, for the most part sluggish, with remissions, and in most cases ends with recovery.

Plant dust lead to acute, subacute, as well as chronic lung lesions. Their mode of action is not clear, and in some cases the harmful agent present in the plant matter of the seeds is unknown, such as certain proteins, alkaloids or other irritating and toxic substances; sometimes their harmful effects are due to biological (bacteria, spores, mycelium) and mineral (silicon) contamination.