During the combustion process, a flame is formed, the structure of which is determined by the reacting substances. Its structure is divided into areas depending on temperature indicators.

Definition

Flame refers to gases in hot form, in which plasma components or substances are present in solid dispersed form. Transformations of physical and chemical types are carried out in them, accompanied by glow, release of thermal energy and heating.

The presence of ionic and radical particles in a gaseous medium characterizes its electrical conductivity and special behavior in an electromagnetic field.

What are flames

This is usually the name given to processes associated with combustion. Compared to air, gas density is lower, but high temperatures cause gas to rise. This is how flames are formed, which can be long or short. Happens often smooth transition one form into another.

Flame: structure and structure

For determining appearance It is enough to ignite the described phenomenon. The non-luminous flame that appears cannot be called homogeneous. Visually, three main areas can be distinguished. By the way, studying the structure of the flame shows that various substances burn with education various types torch.

When a mixture of gas and air burns, a short flame is first formed, the color of which is blue and purple shades. The core is visible in it - green-blue, reminiscent of a cone. Let's consider this flame. Its structure is divided into three zones:

1. A preparatory area is identified in which the mixture of gas and air is heated as it exits the burner opening.
2. This is followed by the zone in which combustion occurs. It occupies the top of the cone.
3. When there is a deficiency air flow, the gas does not burn completely. Carbon divalent oxide and hydrogen residues are released. Their combustion takes place in the third region, where there is oxygen access.

Now let's look separately different processes combustion.

Burning candle

Burning a candle is similar to burning a match or lighter. And the structure of a candle flame resembles a hot gas stream, which is pulled upward due to buoyancy forces. The process begins with heating the wick, followed by evaporation of the wax.

The lowest zone, located inside and adjacent to the thread, is called the first region. It has a slight glow due to a large amount of fuel, but a small volume of oxygen mixture. The process is carried out here complete combustion substances with the release of which are subsequently oxidized.

The first zone is surrounded by a luminous second shell, which characterizes the structure of the candle flame. A larger volume of oxygen enters it, which causes the continuation of the oxidation reaction with the participation of fuel molecules. Temperatures here will be higher than in the dark zone, but not sufficient for final decomposition. It is in the first two areas that when droplets of unburned fuel and coal particles are strongly heated, a luminous effect appears.

The second zone is surrounded by a low-visibility shell with high temperature values. Many oxygen molecules enter it, which contributes to the complete combustion of fuel particles. After the oxidation of substances, the luminous effect is not observed in the third zone.

Schematic illustration

For clarity, we present to your attention an image of a burning candle. Flame circuit includes:

1. The first or dark area.
2. Second luminous zone.
3. The third transparent shell.

The candle thread does not burn, but only charring of the bent end occurs.

Burning alcohol lamp

For chemical experiments Small containers of alcohol are often used. They are called alcohol lamps. The burner wick is soaked with the liquid poured through the hole. liquid fuel. This is facilitated by capillary pressure. When the free top of the wick is reached, the alcohol begins to evaporate. In the vapor state, it is ignited and burns at a temperature of no more than 900 °C.

The flame of an alcohol lamp has a normal shape, it is almost colorless, with a slight tint of blue. Its zones are not as clearly visible as those of a candle.

Named after the scientist Barthel, the beginning of the fire is located above the burner grid. This deepening of the flame leads to a decrease in the inner dark cone, and the middle section, which is considered the hottest, emerges from the hole.

Color characteristic

Various radiations are caused by electronic transitions. They are also called thermal. Thus, as a result of combustion of the hydrocarbon component in air environment, the blue flame is due to the release H-C connections. And with radiation particles C-C, the torch turns orange-red.

It is difficult to consider the structure of a flame, the chemistry of which includes compounds of water, carbon dioxide and carbon monoxide, OH connection. Its tongues are practically colorless, since the above particles, when burned, emit radiation in the ultraviolet and infrared spectrum.

The color of the flame is interconnected with temperature indicators, with the presence of ionic particles in it, which belong to a certain emission or optical spectrum. Thus, the combustion of certain elements leads to a change in the color of the fire in the burner. Differences in the color of the torch are associated with the arrangement of elements in different groups periodic system.

Fire is examined with a spectroscope for the presence of radiation in the visible spectrum. It was found that simple substances from general subgroup have a similar coloring of the flame. For clarity, sodium combustion is used as a test for this metal. When brought into the flame, the tongues turn bright yellow. Based color characteristics highlight the sodium line in the emission spectrum.

It is characterized by the property of rapid excitation of light radiation from atomic particles. When non-volatile compounds of such elements are introduced into the fire of a Bunsen burner, it becomes colored.

Spectroscopic examination shows characteristic lines in the area visible to the human eye. The speed of excitation of light radiation and the simple spectral structure are closely related to the high electropositive characteristics of these metals.

Characteristic

The flame classification is based on the following characteristics:

• aggregate state of burning compounds. They come in gaseous, airborne, solid and liquid forms;
• type of radiation, which can be colorless, luminous and colored;
• distribution speed. There is fast and slow spread;
• flame height. The structure can be short or long;
• nature of movement of reacting mixtures. There are pulsating, laminar, turbulent movement;
• visual perception. Substances burn with the release of a smoky, colored or transparent flame;
• temperature indicator. The flame can be low temperature, cold and high temperature.
• state of the fuel - oxidizing reagent phase.

Combustion occurs as a result of diffusion or pre-mixing of the active components.

Oxidative and reduction region

The oxidation process occurs in a barely noticeable zone. It is the hottest and is located at the top. In it, fuel particles undergo complete combustion. And the presence of oxygen excess and combustible deficiency leads to an intense oxidation process. This feature should be used when heating objects over the burner. That is why the substance is immersed in top part flame. This combustion proceeds much faster.

Reduction reactions take place in the central and lower parts of the flame. It contains a large supply of flammable substances and a small amount of O 2 molecules that carry out combustion. When introduced into these areas, the O element is eliminated.

As an example of a reducing flame, the process of splitting ferrous sulfate is used. If FeSO 4 gets into central part burner torch, it is first heated, and then decomposed into ferric oxide, anhydride and sulfur dioxide. In this reaction, reduction of S with a charge of +6 to +4 is observed.

Welding flame

This type of fire is formed as a result of the combustion of a mixture of gas or liquid vapor with oxygen from clean air.

An example is the formation of an oxyacetylene flame. It distinguishes:

• core zone;
• middle recovery area;
• flare extreme zone.

This is how many gas-oxygen mixtures burn. Differences in the ratio of acetylene and oxidizing agent lead to different types flame. It can be of normal, carburizing (acetylenic) and oxidizing structure.

Theoretically, the process of incomplete combustion of acetylene in pure oxygen can be characterized by the following equation: HCCH + O 2 → H 2 + CO + CO (one mole of O 2 is required for the reaction).

The resulting molecular hydrogen and carbon monoxide react with air oxygen. The final products are water and tetravalent carbon oxide. The equation looks like this: CO + CO + H 2 + 1½O 2 → CO 2 + CO 2 +H 2 O. This reaction requires 1.5 moles of oxygen. When summing up O 2, it turns out that 2.5 moles are spent per 1 mole of HCCH. And since in practice it is difficult to find ideally pure oxygen (often it is slightly contaminated with impurities), the ratio of O 2 to HCCH will be 1.10 to 1.20.

When the oxygen to acetylene ratio is less than 1.10, a carburizing flame occurs. Its structure has an enlarged core, its outlines become blurry. Soot is released from such a fire due to a lack of oxygen molecules.

If the gas ratio is greater than 1.20, then an oxidizing flame with an excess of oxygen is obtained. Its excess molecules destroy iron atoms and other components of the steel burner. In such a flame, the nuclear part becomes short and has points.

Temperature indicators

Each fire zone of a candle or burner has its own values, determined by the supply of oxygen molecules. The temperature of the open flame in its different parts ranges from 300 °C to 1600 °C.

An example is a diffusion and laminar flame, which is formed by three shells. Its cone consists of a dark area with a temperature of up to 360 °C and a lack of oxidizing substances. Above it is a glow zone. Its temperature ranges from 550 to 850 °C, which promotes thermal decomposition of the combustible mixture and its combustion.

The outer area is barely noticeable. In it, the flame temperature reaches 1560 °C, which is due to natural characteristics fuel molecules and the speed of entry of the oxidizing agent. This is where the combustion is most energetic.

Substances ignite at different temperature conditions. Thus, magnesium metal burns only at 2210 °C. For many solids flame temperature is about 350 °C. Matches and kerosene can ignite at 800 °C, while wood can ignite from 850 °C to 950 °C.

The cigarette burns with a flame whose temperature varies from 690 to 790 °C, and in a propane-butane mixture - from 790 °C to 1960 °C. Gasoline ignites at 1350 °C. The alcohol combustion flame has a temperature of no more than 900 °C.

Home gas equipment does not always work flawlessly and uninterruptedly, and any breakdown can pose a serious danger. Therefore, as soon as a malfunction in the operation of the column is noticed, it must be eliminated immediately.

The gas in the column lights up yellow: the balance of the fuel mixture is imbalanced

The correct color of fire is blue. Has she suddenly changed, turned yellow? This may indicate that there is poor air supply to the burner.

And this happens for several reasons:

• The suction openings can become clogged with dust particles that interfere with the normal air supply;
• The gas in the column lights up yellow if the type of equipment does not match the type of gas used.

In the first case, complete combustion of propane/methane requires air - in sufficient quantities. Mixed with gas fuel, it provides high heating intensity of the coolant.

If there is not enough air, and the “gas component” is much larger, the latter does not burn in full, releasing carbon monoxide and turning the light yellow.

You will have to deal with it if the flame soon turns red. This means that even more “blue fuel” enters the burner, its flow rate is disrupted, soot appears, and, for this reason, the column may spontaneously. The equipment must be cleaned, and only a specialist can do this.

Why does the gas in the column burn with an orange flame?

Most often, the suction holes become clogged in new equipment. These are also the consequences of factory processing: after stamping, the oil film still remains in the ignition tube and burner for some time. Dust easily settles on it and, sticking to it, prevents the passage of air, and the supplied “blue fuel” is contaminated with it and the resulting soot, as a result giving the fire an orange color.

will begin with a specialist diagnosing the problem. It may be necessary not only to clean it, but also to replace the nozzle in the burner and adjust the boiler air seal.

Experts believe that advanced user"gas-bearing" devices, having discovered that the color of combustion has changed, is able to adjust the quality of the air-fuel mixture without contacting a technician. But if the gas in the column is red, you should pay special attention to this. When any fuel burns, carbon monoxide is released, commonly called carbon monoxide.

“We have gas in our apartment, what about you?” Recently, Lviv residents do not know the answer to this question from a nursery rhyme. They complain that the gas from the stove burners does not burn with the usual blue flame, but for some reason red. And the quality of such fuel is clearly lower.

The numbers in the bills are sky-high, and the gas is diluted! - Lviv resident Maryana Andrievskaya does not hide her indignation. - I run on red fuel Lenten borscht I cooked for an hour. And at that time the gas meter was spinning as if nothing had happened. But the worst thing was that after spending time in the kitchen, I felt unwell: my head began to spin, I felt nauseous, and I even fainted. I am sure that the fumes of this red gas are to blame for my illness, because I have never complained about my health before. After the experience, I strictly forbade my schoolchildren from turning on the gas stove. Now after school they heat lunches in the microwave - it’s also not very useful, but at least no one faints.

And our gas boiler began to malfunction,” complains Roman Kulbaba, a resident of the Lviv region. “They called a technician, who cleaned the unit and said that there was a lot of soot there, the injectors were completely smoked. The specialist himself said that the reason was low-quality fuel. Now, when we turn on the gas stove, we open the windows wide. But I have no idea what to do with the boiler.

And by the way, it’s not only Lviv residents who complain. The problem affected the whole of Ukraine.

“I have a gas meter,” says Kyiv resident Inna. – Three years ago, my husband and I spent no more than 3 cubic meters preparing food per month. We no longer began to eat or cook, but for some reason the gas meter began to reel in 7 cubic meters per month. I can only explain this by the fact that to prepare the same borscht, whether now or three years ago, you need more gas. Has he become colder, or what?

Ukrainians are seriously alarmed by the unusual color of the gas on the burners. First of all, residents are worried about their health, because who knows if the red gas is poisonous. And of course, people are interested in why Lately The time required to heat water in a kettle or boiler has increased. But at the same time gas meters They correctly calculate cube by cube.

COMPETENTLY

Why does gas change color?

A gas fire can change color for several reasons. According to experts, a blue flame indicates that the gas is burning completely, and its change can occur for several reasons.

The red color of the flame can have two reasons: contamination of the burners or insufficient ventilation, Kievgaz told us. - Most often we receive such a complaint from consumers who have modern plastic windows. According to safety requirements, in kitchens where plastic windows are installed, when using the stove, it is necessary to open the window in ventilation mode, or install a window ventilator.

Experts say that the color sometimes changes due to changes in the ratio of the components of the gas mixture.

The red color may be due to an increase in the amount of nitrogen in the mixture, says Dmitry Marunich, co-founder of the Energy Strategies Fund. – Its presence can actually slightly lower the combustion temperature of the mixture. If you have yellow flame, which means there is more propane-butane in the gas. In this case, this gas will even provide more heat. In Ukraine, according to GOST, household gas must contain at least 93% methane, and the caloric content of gas must be at least 7600 kcal per day. cubic meter. As far as I know, these parameters are controlled. And the same nitrogen is not deliberately added to the gas, since the mixture diluted in this way will be more expensive than the original one. Gas may be of poor quality if it is not cleared of impurities after production and is supplied directly to consumers. This happens if locality located from the deposit itself. In large cities, control is carried out by the regional gas companies themselves.

According to the specialist, there have been several attempts to prove that gas is supplied to consumers worse quality, than is prescribed in state standards, but after all the analyzes, it turned out that it complies with the standards.

By the way, many citizens have Italian boilers that do not work quite correctly with our gas,” continues Dmitry Marunich. - The fact is that Italian gas should have a calorie content of 9,000 kcal per cubic meter, while ours is no lower than 7,600 kcal per cubic meter. Because of this, if the boiler is not adjusted and certified in Ukraine, it may burn more gas.

By the way, in most civilized countries, consumers pay not only for the volume of gas, but also for its calorie content. That is, if the gas is less caloric, then the bill will be lower, and vice versa, if the gas was more caloric.

In Germany, for example, recalculation is done depending on the supply season,” the expert summarizes. – And here they sell only based on volume. Now they say that we need to switch to European system, but even now we have a lot of unresolved problems. The old equipment is so inaccurate that due to the drop in temperature in winter, meters do not take into account about 500 million cubic meters of gas that goes to consumers. First, we need to put things in order in accounting for gas volumes, and only then move on to changing the price depending on its calorie content.

Household gas equipment is considered a high-risk device, so it is important to know some of the symptoms of breakdowns for a prompt response. If you find that in gas appliance When gas burns, yellow color predominates, black soot falls, and you can feel bad smell burnt, most likely the flame smokes. Yellow or Orange color on the flames indicates a lack of air mixture (injection failure). In this article we will talk in detail about gas combustion and analyze external signs bad work gas burner.

Proper gas combustion - blue color

In order for the gas to burn completely, with maximum heat release and high heating intensity, it must receive required amount air, which is mixed with gas in the main burner in the correct proportions. But when the amount of incoming air is limited by something, gas combustion is incomplete and is released a large number of carbon monoxide (CO is a by-product) and the flame turns yellow.

The color of the flame and the thermal load (heating of the coolant) directly depend on the amount of oxygen supplied. Air intake within normal limits turns the flame blue. If the air-fuel mixture is unbalanced (gas predominates), the flame turns yellow, and over time turns red and white. This is caused by increased gas supply to the main burner.As a result, fuel is not consumed correctly - the burner smokes. At the same time, the water heater does not heat the water, the boiler does not warm up the coolant well, the gas stove leaves a black mark on the dishes, “saturating” the food with sulfur.

Gas lights orange or yellow

An imbalance in the air-fuel mixture occurs for various reasons. The air intake holes become clogged with dust particles, preventing the passage of air. In the first year of operation, gas equipment is especially susceptible to plaque. After stamping, the burner and pilot tube retain an oily film for some time. Adhering dust prevents the passage of air, but not gas. Increased gas supply to the burner upsets the balance when mixing the fuel supply to the main burner. When dust or soot falling from above enters with the gas, when burned in the chamber, they give a yellow or orange color to the flame.

A common mistake. At the time of buying gas equipment under a different type of gas, and not the one you are using, is also the reason for the appearance yellow color flame. For proper combustion of propane and natural gas different proportions of air are required. Therefore, if you decide to buy a geyser, pay attention to what type of gas it is configured for.

Concerning gas stove . The air supply control valve may be closed, fallen or come off the mount. By preventing the required amount of air from flowing in. In the absence of sufficient oxygen, only some types of stoves can easily ignite from electric ignition and have a blue flame, the rest lose heat and smoke, the stove should be repaired.

Gas burns red

Carbon monoxide is a byproduct of the combustion of any fuel. Gas water heaters, which have a blue flame when burning gas, emit safe level CO. An orange or red flame indicates an increased presence of CO emissions. The symptoms of carbon monoxide poisoning are similar to those of the flu, headache, dizziness and nausea.

Carbon monoxide is called the “silent killer”, fatally poisoning the unsuspecting user, while being odorless and colorless. Therefore, if the gas burns red and the geyser goes out, you should take care of professional cleaning.

Several decades ago, due to the lack of a gas control system, gas water heaters killed up to a hundred people a year by poisoning them with carbon monoxide. We, as a company engaged in the repair and sale of gas equipment, recommend not to let things get to this point, but at the first manifestation of a malfunction geysers call a professional technician.

What to do in this situation

The solution to this problem begins with understanding that yellow, red or orange gas is dangerous. If these symptoms are detected, the next step will be the scheduled arrival of a qualified technician for a technical inspection and repair of the gas water heater or other gas equipment. Prepare for the fact that you will need to clean the gas water heater, adjust the air seal in the boiler, and replace the burner nozzles. The air-fuel mixture can be adjusted independently. Important element each home boiler room - installation of sensors for the presence of carbon monoxide in the room

Eliminating flame smoking is a simple and short process for craftsmen with extensive experience. The required tool can be found in any home set. On average, our technicians spend about 30 minutes with a client, so choose and calculate a convenient time for your visit and submit a repair request.