Explosions in the furnaces of boilers running on gaseous fuels. Instructions for emergency situations in the boiler room

EXPLOSIONS OF STEAM BOILERS, the destruction of the walls of the boiler, in which an instant equalization of pressure inside the boiler and atmospheric pressure is obtained, and the water heated in the boiler also instantly passes into a vapor state, and its huge potential energy is converted into kinetic energy. Statistics on steam boiler explosions in different countries show that about 60% of such explosions are due to poor care and cleaning. So, for 1925 and 1926, in Germany, explosions of steam boilers are distributed according to reasons in the following way: from design, material and installation flaws - 24%, from water leakage in the boiler - 39%, from corrosion and overheating of the walls - 23% and from various other reasons - 14%. Data on explosions of steam boilers in France for the period from 1880 to 1900, published in Annales des Mines, also confirm that largest number explosions are due to poor maintenance of the boilers. So, for example, for the period 1895-1900. Steam boiler explosions were distributed according to causes as follows: from design and installation defects - 14%, from unsatisfactory maintenance and cleaning - 55%, from low water levels - 6%, from excess pressure - 5% and from various other causes - 20%.

The strength of the explosion and the destruction caused by it depend on the size of the water space of the boiler and the temperature of the heated water. Therefore, explosions of steam boilers with a large water space (for example, cylindrical boilers) are the most severe in their consequences.

At present, despite the use of more high pressures, explosions of steam boilers occur less frequently and are less dangerous in their consequences than before, which can be explained by: the publication in almost all countries of rules and regulations that regulate the construction of new boilers and supervision during operation; improvement of boiler designs, quality of boiler material (Fig. 1) and methods of its processing; the ever-growing use of water-tube boilers (i.e., more efficient boilers, but with a relatively small water space); improved methods of studying the causes of the explosions themselves and, finally, raising the level of skill of stokers.

Causes of steam boiler explosions. These reasons can be put into two categories: 1) reasons beyond the stoker's control- deficiencies in the design and installation, unsatisfactory repair of the boiler (bad riveting, welding, etc.) and low strength of the material; 2) reasons depending on the stoker- poor condition of the boiler and its fittings, an increase in pressure above the permitted level, a decrease in the water level, which can lead to heating of the boiler walls.

1. Deficiencies in design and materials. A number of explosions that took place in recent times, occurred due to dangerous stresses in the boiler material during its heating due to irrational connections, unnecessary thickening of the material, heating of parts of the steam space that are in contact with high temperature gases, poor water circulation and other defects in the boiler design. Due to uneven heating of the walls of the boiler, the latter are deformed and sag, the edges of the bottoms are especially deformed. The same danger in relation to explosions is presented by bottoms having an irrational convexity, as well as flat bottoms, in which the edge is bent at a right angle. The design flaws should also include: inaccurate fit of sheets, inept riveting of sheets, and a number of other defects. Usually, most of these defects make themselves felt in the form of bulges and cracks (Fig. 2, 3 and 4).

In this case, b. A major overhaul has been undertaken to eliminate these causes. Bottoms of incorrect design must be replaced by others in accordance with the latest regulations.

One of the best measures to prevent explosions in steam boilers is to use high quality material and correct handling this material. Incorrect processing in the sheets results in harmful residual stresses, which, in case of accidental occurrence of other defects (for example, overheating or corrosion of the material), lead to an explosion of the boiler. The transformation of the structure of boiler iron into coarse-grained due to overvoltage and subsequent heating to 600-700° is shown in Fig. 5.

2. Excess pressure, if it is not the result of an oversight on the part of the stoker, it may be due to improper loading safety valve or insufficient size of the latter.

3. Lack of water in the boiler may happen. arr. due to poor condition or improper functioning of water-indicating and nutritional devices. Especially dangerous is the lack of water in boilers with flame tubes, since overheating of the flame tubes leads to their collapse and possible destruction (Fig. 6).

If there is a lack of water in the boiler, it is necessary to immediately remove the fire from the furnace and isolate the boiler by closing the steam and feed valves. Only upon detection of shortcomings and their elimination, it is possible to start filling the boiler with water.

4. Boiler wall corrosion are internal and external. a) Internal corrosion is the result of oxidation under the influence of acids or air. In the feed water, chloride salts of magnesium, calcium and sodium are often dissolved, which, decomposing at a relatively low temperature, form hydrochloric acid, which quickly corrodes the walls of the boiler. Sulfuric salts of iron, aluminum and magnesium are also very dangerous; the destructive effect of the first two salts is especially noticeable in the case of scale formation in certain places of the boiler, because in such places, due to the accumulation of heat, these salts decompose and form free sulfuric acid, which corrodes the boiler walls (Fig. 7).

The harmful effect of such feed water usually found in leaks at the edges of the sheets and near the rivets. Air dissolved in water can corrode the boiler wall to a crack if the metal stress is above the elastic limit (Fig. 8).

Recently, Professor Parr (USA), based on a number of studies, put forward the so-called alkaline hypothesis, specifically concerning the destruction of rivet joints under the influence of alkalis. According to this hypothesis, the alkalis present in the feed water, especially caustic soda, penetrate into rivet seams, under rivet heads, etc., and concentrate there; at the same time, if there are stresses in the material that exceed its yield strength, alkalis make the metal brittle and thereby cause destruction in it; the resulting cracks usually go from one rivet hole to another, but never go beyond the rivet seam.

The prerequisites for this hypothesis are, therefore, two conditions: a strong concentration of alkali in the rivet seams and overstressing of the material. The first premise, which assumes that all riveted joints are loose (otherwise the feed water could not penetrate them), is still disputed by the German school, headed by Professor Baumann; the second premise does not meet with objections, since Professor Bauman also establishes that the stresses in boiler seams sometimes exceed the yield strength of the material. To prevent all these types of corrosion, the feed water, before it enters the boiler, is neutralized by appropriate cleaning or deposits and scale are removed in a timely manner. Internal corrosion can also be caused by the use of condensate water containing lubricating oil. Fat deposits on the walls of the boiler, preventing the passage of heat into the water space, cause overheating of the material and the formation of acids. A locomotive boiler that exploded due to internal corrosion is shown in Fig. nine.

b) External corrosion are obtained under the influence of oxygen acting in the presence of moisture on the outer surface of the boiler. One of the more common causes of external corrosion is poor riveting or bad embossing. The resulting leak is detected during a hydraulic test of the boiler. The most reliable measure might be. riveting of several rivets. Another form of external corrosion is observed in locomobile and vertical boilers with an internal firebox, namely - in their lower part - in contact with the grate, where the presence of ash, greedily absorbing moisture, causes oxidation of the walls (Fig. 10).

Countermeasures: systematic cleaning bottom surface boiler walls and timely removal of ash. Further, corrosion can occur if the boiler rests directly on brickwork, since water seeping through it can cause rusting of the boiler walls. Therefore, the boilers are supported on cast-iron beams or iron rails, or erect masonry on cement. Rivet seams covered with lining can present a particular danger, as they make it difficult to inspect them. External corrosion is also caused by incorrect design and poor fitting of fittings, especially valves, which can lead to dangerous leakage. Finally, sulfur dioxide gases (sulphurous anhydride, sulfates, etc.) emitted by the fuel and causing rapid destruction of rivet joints (Fig. 11) can serve as a cause of corrosion. Countermeasures: switching to another fuel and caulking or re-riveting defective seams.

5. Scale prevents the passage of heat into the water space and leads to complete destruction separate parts boiler, causing an explosion hazard (Fig. 12).

One of the more rational measures to prevent the formation of scale is to treat the feed water before it enters the boiler. This cleaning can be done mechanically or by chemical means. mechanical way consists in trapping impurities in a special vessel, and those of them that are heavier than water are directly deposited; those that are lighter than water are retained in a filter filled with a layer of gravel or coke (Reisert-type filter). Chemical cleaning produced in special devices(for example, Dervo systems), where feed water, depending on its composition, is treated with various reagents: lime - to precipitate calcium, then soda, and more recently permutite (aluminous silicate) - to convert insoluble sulfate salts of lime into sulfate salt sodium, which is highly soluble in water. The need for purification of feed water depends on the boiler system, the nature of its operation and the degree of its forcing. For boilers with a large water space, treatment of feed water can be considered necessary if its hardness exceeds 12 German degrees (1 German degree of hardness corresponds to a content of 1 G CaO in 100 liters of water). For those types of boilers where descaling is difficult, water purification is highly recommended already at 6-7 German degrees. Another very rational, but expensive way to purify water is to evaporate it and deposit the resulting steam in evaporators. This method has recently found application, in addition to ship boilers, also for stationary steam plants, especially if there is steam turbines. Since in the latter case the condensate can be used to feed the boiler, only about 5-15% of the total amount of feed water needs to be treated. Among other measures to prevent the formation of scale, one can point to the systematic blowing of the boiler and, finally, to the circulation device, which ensures the deposition of sediments in the places designated for this.

6. Weakening of the material after a long service life of the boiler. After prolonged operation, the material of the boiler is reborn. Although the issue of aging (fatigue) of the boiler material has not yet been finally resolved, however, there is no doubt that it eventually loses its original properties and, above all, the necessary viscosity. In addition, over time, the thickness of the sheets, as a result of rusting, decreases, and defects in rivet joints occur, for example, their weakening, etc.

Measures to combat explosions of steam boilers. These measures can be divided into two categories: 1) measures taken during boiler service- timely elimination of detected defects, which are often precursors of an explosion (these measures were indicated when considering individual causes of steam boiler explosions); 2) legislative measures: a) the rules governing the construction of steam boilers in relation to: the quality of the material, the study of the material and the methods of its processing; b) binding regulations and rules governing the supervision of steam boilers.

a) Regulations governing the construction of steam boilers. The use of high pressures for boilers, reaching up to 50-100 atm, and high superheat temperatures of steam, reaching 400 °, made it necessary to revise the standards already existing in some countries for the construction of steam boilers and issue new ones instead. That. the Würzburg and Hamburg norms that existed in Germany, published in recent years of the past and in the first years of this century, were replaced by new standards that entered into force on October 12, 1926. According to the new standards, materials used for the construction of steam boilers must be examined by experts who issue appropriate certificates. In addition to tensile strength and allowable elongation for various materials used in boiler building, the new standards establish, which is especially important, the minimum limits for the radii of the sides of the bottoms, since irregular shape bottoms often caused explosions. The same norms were published in 1924 in the USA. New American standards distinguish between fire and side plates. In addition, they prescribe for boiler sheets, depending on the grade, the limiting content of carbon, manganese, phosphorus and sulfur, which is not provided for by German standards. These standards establish minimum limits for tensile strength and elongation for side, fire sheets and other materials. AT general norms these are largely based on empirical formulas, in contrast to the German norms based on Ch. arr. on calculated data and being the product of long-term research.

b) Mandatory ordinances and regulations governing the supervision of steam boilers. Almost all countries have issued regulations governing the supervision of steam boilers. This supervision is carried out in different countries directly by government bodies, or by private companies representing associations of boiler owners, who are obliged in their actions to obey the rules existing for this purpose. These rules provide for the technical examination of steam boilers within the established time limits. So, the next examinations of the boiler, according to the rules of the tubing of the USSR, should be carried out normally within the following periods: external examination - once a year, internal examination - once every three years, hydraulic test combined with internal examination - once every six years. In relation to boilers that are more than 25 years old, the tubing rules provide for the study of the material during the next repair of the boiler.

Among heating systems, boiler houses remain the most popular option for generating energy and heat. At the same time, boiler rooms, according to the current norms of the law, are classified as hazardous production facilities that require increased attention to maintenance and operation. The source of danger of boiler equipment - high pressure and application gas fuel. According to statistics, accidents in boiler houses are the most frequent man-made emergencies in the thermal power industry.

Possible causes of the accident

The emergence of an emergency situation is associated with a number of factors. Accidents in boiler houses occur primarily due to wear and tear of equipment and communication systems. According to statistics, average value depreciation of communication in heat supply is 65%. An accident in the boiler room also becomes a consequence of the following reasons:

• fuel. The use of a gas mixture makes the boiler a "time bomb" and violation of modes correct operation may cause an explosion. The cause of the explosion of gas boilers is the supersaturation of the combustible mixture that occurs when unburned fuel accumulates. Another cause of a fuel explosion is a malfunction of the burners;
• lower water level. Maintaining the required water level is a guarantee normal operation boiler. Long-term operation of boiler equipment with insufficient water level can lead to heating of steel pipes and their melting;
• violation of water treatment. Accidents in boiler rooms involving industrial boilers occur due to insufficient water softening or water pollution. Water treatment is a mandatory procedure to reduce the amount of scale formed and eliminate excess oxygen, which causes pitting oxygen corrosion. The cause of an accident due to a violation of water treatment is characterized by the appearance of through rust on a small area of ​​equipment, leading to a malfunction, which can cause an accident;
• violation of the boiler heating rules. When starting or stopping the boiler house, the equipment experiences increased loads, which requires strict adherence to the operating rules. Compliance with the warm-up schedule and following the stages of the necessary start-up operations will serve as a guarantee long term boiler service and prevent an accident.

Additional causes of accidents in boiler rooms are mechanical damage to pipes, improper storage of the boiler in idle mode, and errors in the installation of boiler equipment.

To avoid such problems, it is necessary to carry out certification of gas equipment in a timely manner. On the order of the procedure and the list of documents.

Statistical data on accidents in boiler houses

Specially crafted government agency– Rostekhnadzor, performs the task of ensuring safe work hazardous industrial facilities and monitors how the elimination of accidents at gas boilers takes place. Statistical data are recorded annually, allowing to trace the dynamics of the situation in the country as a whole and in individual regions, to track the most common causes accidents at boiler houses, the statistics for which is in tabular form for ease of perception. The statistics of accidents at boiler houses for 9 years is given in the following table:

In parallel with the general accounting of accidents at boiler houses, the statistics include data on the distribution of the category of workers injured in an emergency, the ratio of cases by traumatic factor, the distribution of emergency failures by type of boiler equipment.

For example, accidents at gas boilers, whose statistics are 43.2% of the total mass of all types of devices, rank first in terms of accidents. Indicators showing an increase in emergency cases may indicate gradual exit equipment failure and deterioration.

Consequences of the accident and their elimination

Any organization that has pressure equipment and is engaged in ensuring the production of heat must have a developed plan, according to which the elimination of accidents at gas boilers is carried out. It should contain the priority actions of the personnel, the warning system in the event of an emergency, the list of responsible persons responsible for the hazardous production facility. An important part The plan is to establish the extent of damage, the actions needed to eliminate them and the timing of repairs.

Upon the occurrence of an emergency, a commission is appointed, whose members include technical experts of Rotekhnadzor, whose duty is to conduct an examination.

Based on the results of the investigation, he draws up an act on the accident at the boiler house, which displays the consequences of the incident in the boiler rooms, the causes of occurrence, a descriptive part and technical information about the incident.

Real cases of accidents in boiler rooms

October 2016. There was a failure in Balashikha automatic system boiler room, which led to the failure of ventilation. The resulting explosion, which was caused by the accumulation of exhaust gases, damaged ventilation box and broke the windows of the building. No harm done.

December 2016. In Buzuluk, due to a pipeline break inside the boiler house, an emergency occurred, which resulted in a violation of the heating system of several microdistricts. Due to the consequences of the incident, residential buildings, schools and children's institutions were left without heating. Their liquidation required two days of intensive work of public utilities.

January 2017. As a result of the water hammer, the water supply was cut off in Shcherbinka. This is a small settlement, which is part of New Moscow. Feedback from residents suggests that the accident was promptly eliminated.

Another emergency occurred in Krasnogorsk. The accident happened due to the failure of the pumps. More than 12 thousand residents were left without heat supply for a long time at an ambient temperature of -25 degrees.

February 2017. In Kemerovo, when inside the boiler house, which arose as a result of a transformer fire, the heat supply was disrupted to several. Prompt arrival at the place of utility services made it possible to quickly reconnect the heat carriers to the backup operation scheme.

Steam and hot water boilers- devices having furnaces for burning fuel and designed to produce steam and hot water, respectively, used outside the boilers themselves; the heating process takes place at a pressure above atmospheric.

At PMP, steam boilers are used to prepare steam, and boilers and hot water boilers are used to prepare hot water. various types and designs.

The main causes of steam boiler explosions are:

1. Leakage of water (a sharp decrease in the water level in the boiler).

Leakage of water in the boiler leads to:

a) overheating of the boiler in the furnace part. The boiler wall heats up above the critical temperature. In this case, the mechanical properties of the metal change, its strength decreases, and under the steam pressure the walls are blown out, which can result in an explosion.

b) ingress of water on the overheated walls of the boiler. To prevent the possibility of water dropping below the permissible level, boilers must be equipped with devices for automatic control of the upper and lower limit water levels, automatic shutdown of fuel supply to the burners, two direct-acting water indicators, etc.

2. Excess allowable pressure in the boiler. It is a violation of the specified mode of its operation, a malfunction of the safety equipment. To prevent exceeding the permissible pressure, the boilers are equipped with pressure gauges and safety valves.

Pressure gauges are checked by the Gosstandart once a year, and once every 6 months they are controlled at the enterprise by a control pressure gauge.

3. Scale formation. Unsatisfactory water regime, i.e. violation of the quality and hardness of water, the supply boiler is the cause of the deposition of sludge and scale on the inside. boiler walls and overheating of the boiler walls is observed.

4. Defectiveness and malfunction of the main structural elements boiler, lowering them mechanical strength during operation, malfunction of safety equipment and measuring instruments.

5. Explosion of gases from the furnace part of the boiler. Cause: violation of the operating modes of draft devices or fuel supply.

For early detection possible defects boilers, they are subjected to technical certification, which is carried out by inspectors of Promatomnadzor in the presence of the head of the boiler room. An internal inspection is provided once every 4 years and hydraulic tests 1 time in 8 years, test pressure (1.25 - 1.5) R working.

Boilers that are not subject to registration with the Promatomnadzor bodies are examined by the person responsible for operation: internal inspection once every 1-2 years after cleaning and repair, hydraulic tests once every 6 years.

Maintenance of steam boilers may be entrusted to persons not younger than 18 years of age who have passed a medical examination, trained in an appropriate program and have a certificate from the qualification commission for the right to maintain boilers. These individuals are re-screened:

When transferring the boiler to another fuel;

Periodic, 1 time in 12 months;

When moving to another company.

The boiler explosion mechanism is simple. The risk zone mainly includes those boilers that do not work constantly, but sporadically. Weak spots are located where the heating system can be "grabbed" by ice - these are expansion tanks, circulation pipes and cold rooms such as attics.

The main reason why boilers explode is the freezing of the heating system, while the water in the pipes stops circulating. The fuel continues to burn. Water boils inside the cast iron (metal) sections of the boiler or pipes. In this case, the vapor pressure inside the system begins to increase very rapidly. At some point, a critical point of pressure growth will be reached, which the metal cannot withstand - and it is already impossible to predict what the consequences of the destruction of pipes and sections of the boiler will be. The fact is that at the same time a very large volume of steam-water mixture is ejected into a closed space. The pressure inside the room is rising rapidly. And, at best, everything will end in broken glass. In the worst case scenario, the structures of the room will be destroyed, causing harm to people's health or even death of people in the area of ​​the explosion, as a result of the collapse of the structures of the boiler room.

So, for example, on 01/04/2016 there was an explosion of a household solid fuel boiler installed in the apartment of a blocked residential building in Lyakhovichi. No one was hurt, the building envelope of the furnace room where the boiler was installed was damaged. The cause of the explosion was the lack of water circulation in the heating system, presumably as a result of the heating system, presumably as a result of the formation of an ice plug in the outlet pipeline. Contributing factors - unsystematic mode of boiler combustion, forced operation of the boiler by a person not knowing the rules safe operation boiler.

On January 8, 2017, in the city of Luban (Minsk region), a household solid fuel boiler exploded in the boiler room of a residential building. The explosion caused the collapse brick wall, the roof was damaged, the boiler room and the boiler were destroyed. There were no casualties. The cause of the explosion is being established.

Over the past eight years, this is already the seventieth emergency situation that occurred during the operation of domestic heating boilers.

To reduce the risk of freezing piping in the boiler and heating system, Safety Regulations require owners to potentially dangerous objects, i.e. boilers, so that the installation and adjustment of heating systems is carried out only by specialized organizations registered in the territory of the Republic of Belarus and having at the same time the appropriate permit (license) of Gospromnadzor to perform this type of work.

At the same time, employees or specialists of this organization must train the owner in the rules for the safe operation of the boiler and heating system and make a note about this in the boiler passport.

Before starting the boiler, the homeowner must make sure that the shut-off systems must be opened on two pipelines at once - the one that supplies the coolant to the boiler, and the one that removes the coolant from the boiler. All you need to do is open locking devices installed on the heating system. From the bottom branch chimney accumulated condensate must be removed. This will help avoid poisoning. carbon monoxide. The condition of the chimney head and chimney channels should be checked regularly. Before starting to fire up the boiler, it is necessary to open the system make-up line and the filling control line. expansion tank. The fact that the system has not frozen will become clear when water starts to flow from the control line.

But let's imagine the following situation: no water has flowed from the control line of the heating system. What to do in this case? If the pressure in the boiler increases continuously and reaches the pressure water supply network, this indicates that the heating system is frozen. In this situation, it is strictly forbidden to kindle the boiler. There is no need to hope that the steam will overcome the ice plug - along with this, the steam will smash both the pipeline and the boiler. It is necessary to determine the approximate place of freezing of the heating system, warm it up and check whether water ran out of the control lines of the heating system with open make-up. And only if this happens, start igniting the boiler, while monitoring the readings of the pressure gauge. If the pressure of the coolant in the heating system approaches the maximum allowable, you must immediately stop the fuel supply. If the boiler runs on local fuels, it must be removed from the boiler to a safe place. This state of the heating system indicates that the heating system is not warmed up.

Infrequently, but it also happens that the boiler installed there freezes in the attic. Like a pipe, it is strictly forbidden to warm it with an open fire; this can be done using, for example, hot water. However, if during heating you saw that water came out from the heating surface of the boiler, this means that the boiler has depressurized. And there is only one way for him - to the repair shop. In this state, the boiler is unsuitable for further operation. A steel boiler will be digested by specialists who have the appropriate permission, but, in a cast-iron boiler, they will replace the damaged sections and repack them again.

Of particular concern in the Gospromnadzor bodies is the operation of boilers created (welded) by the so-called “kulibins” (craftsmen) in the people.

Over the past five years, eight of the boilers that exploded were homemade. Craftsmen somehow riveted heating units. But it is clear that in this case there is a huge risk that problems can begin with heating surfaces, furnaces, stagnant zones of boilers ... In the end, this ends up with the water overheating, which leads to the rupture of the boiler. In addition, it must be borne in mind that, as a rule, neither thermometers, nor pressure gauges, nor safety valves are installed on “home-made products”.

And therefore Gospromnadzor warns: do not use homemade boilers and do not entrust the installation of certified heating units to persons who do not have special qualifications. The money you save on this can come back to haunt you with a fire, severe destruction or severe injury to people. So is it necessary to take risks for the sake of saving material resources with your property, housing, and maybe health or even life?

Chief State Inspector Pavlyushchenko V.V.

Leading State Inspector

Misyun V.M., Kazimirsky O.S.

POSSIBLE EMERGENCIES

Emergencies that cause a violation of the normal operation of boilers, in which, according to the requirements of the Rules for the Design and Safe Operation of Steam and Hot Water Boilers, they must be immediately stopped by the operation of automation or personnel on duty, include:

Safety valve failure detection;

If the pressure in the boiler drum has risen by 10% above the allowed one and continues to grow;

Reducing the water level below the lowest permissible level, in this case, feeding the boiler with water is strictly prohibited;

Raising the water level above the highest permissible level;

Termination of all nutrient pumps;

Termination of all direct water level indicators;

If cracks, bulges, gaps in their welded seams, breakage of an anchor bolt or connection;

Unacceptable increase or decrease in pressure in the once-through boiler path to the built-in valves;

Extinction of torches in the furnace during chamber combustion of fuel;

Reducing the water flow through the boiler below the minimum allowable value;

Decrease in water pressure in the boiler path below the permissible level;

Increasing the temperature of the water at the outlet of the boiler to a value 20°C below the saturation temperature corresponding to the operating water pressure in the outlet header of the boiler;

Malfunctions of safety automatics or alarms, including power failure on these devices;

The occurrence of a fire in the boiler room that threatens the operating personnel or the boiler;

The appearance of leaks in the lining, at the installation sites of safety-explosion valves and gas ducts;

Interruption of power supply or loss of voltage on remote, automatic control devices and measuring instruments;

Malfunctions of instrumentation, automation and signaling equipment;

Failure of safety locking devices;

Malfunctions of burners, including non-barriers;

The appearance of gas contamination, detection of gas leaks on gas equipment and internal gas pipelines;

Explosion in the furnace space, explosion or ignition of combustible deposits in gas ducts;

Accidents in the gas industry.

CAUSES AND CONSEQUENCES OF ACCIDENTS AND FAULTS IN THE OPERATION OF BOILERS

The most serious consequences of the accident are explosions when the density of the boiler is violated due to non-compliance with the operating modes and operating rules, as well as explosions associated with the gas contamination of the furnace due to improper maintenance and combustion of fuel.

Pops and explosions occur in the furnace and gas ducts when the concentration of gas in the air is in the range of explosive limits and an explosive gas-air mixture is created.

In a boiler house operating on solid fuel, during layered combustion of fuel in the furnace and gas ducts, combustible gases are released in large quantities from fresh fuel if, during a short stop of the boiler, it is thrown onto the remaining unburned fuel, and not removed from the furnace.

The reasons for the formation of an explosive gas-air mixture in the furnaces and gas ducts of a gasified boiler house may be incorrect actions of personnel during the operation of the boilers, a malfunction of the locking devices in front of the burners and turning them on when the automatic flame control is faulty or turned off, the lack of devices for monitoring the tightness of the shut-off organs of the burners.

When burning liquid fuel, fires and explosions in the furnace and gas ducts occur in the case of poor-quality atomization by nozzles, which leads to leakage of fuel oil into the embrasure and onto the walls of the furnace. In case of poor mixing of fuel oil with air and its incomplete combustion, there is an increased removal of soot into the gas ducts. In the event of fires of deposits and soot, the temperature of the gases rises, the thrust decreases, the skin heats up significantly, and sometimes the flame is knocked out.

The cause of the accident may be the unsatisfactory water regime of the boilers. As a result, deposits of scale are formed, causing an increase in the temperature of the metal of the pipes and their burnout. The accumulation of scale and sludge can also lead to disruption of water circulation. Causes of damage and accidents may be a factory defect in the boiler, poor quality the material from which individual components of the boiler are made, as well as the unsatisfactory condition of the equipment due to poor installation or repair.

Table 1 lists typical cases of accidents and malfunctions in the operation of boiler houses and indicates their causes and possible consequences.

Table 1

Typical cases of accidents and failures in the operation of boiler houses, their causes and possible consequences

Malfunction

Possible consequences

Fire in the boiler room

Non-compliance with the requirements of the production instructions and fire safety rules. Ignition of flammable materials and substances. Malfunctions in the operation of boiler equipment. Malfunction of the boiler safety automatics. Electrical fault

Accidents and loss of life. Material damage

NOTIFICATION PROCEDURE IN CASES OF EMERGENCIES

Owners of boilers registered with Gospromnadzor are obliged to immediately notify the territorial technical supervision body and other state institutions of each accident, fatal, severe or group accident in accordance with the regulation on the procedure for technical investigation of the causes of accidents and incidents at hazardous production facilities.

The personnel on duty servicing boiler plants, in case of any failure in the operation of equipment, an accident, an accident, and in the event of a fire or a threat of fire, must:

Immediately notify the person responsible for the good condition and safe operation of the boilers (head of the boiler room);

notify everyone officials according to a pre-compiled list;

Prior to the arrival of the commission to investigate the circumstances and causes of the accident or accident, ensure the safety of the entire situation of the accident (accident), if this does not pose a danger to human life and health and does not cause further development of the accident or emergency;

Draw up an explanatory note, which will be the primary document of the preliminary investigation into the causes of the accident.

GENERAL SAFETY PRECAUTIONS IN THE EMERGENCY OF SOLID, LIQUID AND GAS FUEL BOILERS

When eliminating accidents associated with an emergency shutdown of boilers, the maintenance personnel must be able to quickly assess the current emergency situation, remain calm and act confidently at any stage of the development of accidents.

In case of emergency shutdown of boilers, the following safety precautions must be observed.

When the boiler house is operating on solid fuel, the burning fuel from the furnace of the stopped boiler should be removed. In exceptional cases, when it is impossible to quickly remove fuel from the furnace, burning fuel can be filled with water. At the same time, the driver (fireman) should pay special attention to ensuring that the water jet does not hit the walls of the boiler furnace and the lining. It is possible to fill in the slag being scooped out only with the use of a fire hose from a distance that ensures the safety of personnel during pouring (at least 2-3 m).

It is forbidden not only to "damp" the flame with fuel, but also to stop the air supply when the fuel is removed. If this instruction is not followed, then this will lead to the ejection of the flame from the furnace with gases accumulated in it and injury to the attendants.

Locks must be put on the doors of the furnace, which exclude the possibility of ejection of gases and flames from the furnace and smoke in the boiler room.

When the boiler is operating on liquid fuel, the fuel supply to the nozzle or air is immediately shut off when the air spray nozzle is installed. If the design allows, the nozzle is removed from the furnace. The valve is turned off at the outlet of the pipeline to the nozzle of the emergency boiler, the common valve of the intra-boiler pipeline.

When the boiler room is operating on gaseous fuel, the shut-off device at the inlet of the gas pipeline in front of the boiler room or the safety shut-off valve and the shut-off valve in front of the emergency boiler are closed to disconnect it from the general gas pipeline.

At the same time, the gas supply is first quickly shut off, then the air supply, and then the valve on the safety plug gas pipeline is opened.

The operation of gas equipment with disabled control and measuring devices, interlocks and alarms provided for by the project is prohibited.

HAZARDOUS ACTIONS OF BOILER ROOM SERVICE PERSONNEL, CAUSED POSSIBILITY OF EMERGENCY SITUATIONS

In order to avoid possible accidents and failures during the operation of the boiler equipment, the operator (fireman) is prohibited from:

Seize safety valves or additionally load them;

Perform on boilers that are under pressure, repair work(lubricate bearings, stuff and tighten seals, flange bolts);

Open and close fittings with hammer blows or other objects, as well as with the help of elongated levers;

To allow the water level in the steam boiler to fall below the permissible lower level or rise above the permissible upper level;

Allow the arrow to cross the red line indicated on the pressure gauge;

Purge the boiler in case of faulty purge fittings;

Blow out the boiler from soot, blow it out without using gloves and goggles;

Use open fire to find gas leaks;

Enable and disable electrical devices if there is a smell of gas in the boiler room;

Turn on and off the electric motors of pumps and smoke exhausters without electrical protective gloves and in the absence of electrical equipment grounding;

Use electric lamps with a voltage of more than 12 V in chimneys and boilers;

clutter the boiler room with foreign objects;

Perform any other duties while on duty that are not provided for by the production instruction;

Leave the boiler without constant monitoring both during the operation of the boiler and after it has stopped until the pressure in it drops to atmospheric;

Allow unauthorized persons who are not related to the operation of boilers and boiler room equipment.