Is coal combustion a spontaneous reaction under ignition conditions? Is combustion all a spontaneous

Under a given condition, the process or reaction that can be carried out automatically once initiated without external help is called a spontaneous reaction, so combustion is not a spontaneous reaction.

Combustion, commonly known as "**" and "ignition", is a chemical reaction that exothermics and emits light.

It must meet three conditions:

1. There should be combustible substances. Regardless of solid, liquid, or gas, any substance that can react violently with oxygen or oxidants in the air is generally called a combustible substance, such as wood, gasoline, alcohol, hydrogen, and acetylene.

Wait; 2. There should be combustible substances. Any substance that helps and supports combustion is called a combustible substance. Such as air (oxygen), chlorine.

and potassium chlorate, potassium permanganate.

and other oxidants. Combustible gas emitted when a combustible substance is heated.

It can only be burned after mixing with oxygen. Combustible substances are completely combusted, and there must be sufficient oxygen. It has been determined that the volume of oxygen in the air generally accounts for about 21, and the oxygen content of general combustible substances in the air is less than 14%-18, and combustion will not occur.

3. There should be a fire source. Any thermal energy source that can cause the combustion of combustible substances is called an ignition source. Such as the flame of common matches, oil lamps, electric sparks, etc.

To make combustible substances burn, they need to have enough temperature and heat, and different combustible substances require different temperatures and heat when burning.

The above three conditions must be met at the same time, and they must be combined with each other and interact with each other for combustion to occur.

First, the coal must be flammable, secondly, it must have flammable gases such as oxygen or hydrogen, and finally it must have a ignition point. can burn.

What are the causes of natural combustion of coal, and what are the conditions for its spontaneous combustion.

Tips: Regarding the cause of spontaneous combustion of coal, there are many imitation theories to explain, and the generally recognized theory is the theory of coal-oxygen recombination, the main point of view is: coal absorbs oxygen in the air at room temperature, produces low-temperature oxidation, and Song Chan Sui releases heat and primary oxidation products, due to poor heat dissipation, heat accumulation, temperature rise, accelerates the process of low-temperature oxidation, and eventually leads to natural ignition.

The following conditions must be met at the same time for spontaneous combustion of coal: (1) Coal has a tendency to spontaneous combustion and is accumulated in a broken state.

There are many theories to explain the causes of spontaneous combustion of coal, and the generally accepted theory is the theory of coal-oxygen recombination, the main point of view is: coal absorbs oxygen in the air at room temperature, produces low-temperature oxidation, releases heat and primary oxidation products, and due to poor heat dissipation, heat accumulation, temperature rises, accelerates the process of low-temperature oxidation, and eventually leads to natural ignition.

Spontaneous combustion of coal must meet the following conditions at the same time:

1) Coal has a tendency to spontaneously combust and is piled up in a broken state.

2) Continuous ventilation and oxygen supply to maintain the continuous development of the oxidation process of coal.

3) The heat generated by coal oxidation can be accumulated in large quantities, and it is difficult to dissipate it in time.

4) The above two or three conditions exist at the same time and the time is greater than that of coal.

During the combustion reaction, if the resulting combustion products can no longer be burned, what is it called? As follows:

a.Burn completely.

b.Incomplete burning filial piety defeated Zheng burning.

c.Evaporation burns and burns.

d.Surface burning.

Which of the above four options will you choose?

Correct answer: aBurn completely.

Complete combustion refers to the combustion of all combustible substances (carbon, hydrogen, sulfur, etc.) contained in the fuel after oxidation to produce only carbon dioxide, water and sulfur dioxide. Because the calorific value of the fuel can be fully released during complete combustion, so that the fuel can be fully utilized, in the combustion equipment, it should be completely burned as much as possible. Achieve complete combustion of fuel.

The following conditions must be met:

1) There should be good combustion equipment suitable for the fuel variety;

2) When burning lump coal, the fuel should be evenly distributed on the grate (grate) as much as possible, the secondary air should be reasonably used when burning pulverized coal, and the good atomization quality should be ensured for liquid fuel;

3) Provide an appropriate amount of combustion air, that is, the excess air coefficient should be appropriate;

4) Carry out the necessary control of the combustion temperature so that it is not too low or too high;

5) Ensure that the fuel has enough residence time in the furnace (or combustion chamber). Choosong.

When the substance is completely transformed, it is "completely burned".

When the combustion products (flue gas, ash slag) after combustion no longer contain combustibles, that is, there is no solid combustible matter (solid carbon) left in the ash slag, and no combustible gas (CO, H2, CMHN) exists in the flue gas, it is called complete combustion.

During the combustion reaction, if the combustion products generated can no longer be burned, it is called complete combustion.

To achieve complete combustion of fuel, the following conditions must be met:

1) There should be good combustion equipment suitable for the fuel variety;

2) When burning lump coal, the fuel should be evenly distributed on the ruler or grate (grate) as much as possible, the secondary air should be reasonably used when burning pulverized coal, and the good atomization quality should be ensured for liquid fuel;

3) Provide an appropriate amount of combustion air, that is, the excess air coefficient should be appropriate;

4) Carry out the necessary control of the combustion temperature so that it is not too low or too high;

5) Ensure that the fuel has enough residence time in the furnace (or combustion chamber).

The burner structure that ensures the complete leakage of full combustion:

The size of the burner to ensure complete combustion is nearly 30% smaller than that of the ordinary burner with the same output, and the motor can be cooled more effectively because the burner head and the motor are arranged in parallel with the shaft, and the internal structure is carefully designed, and the motor is placed in the recess of the air inlet.

The burner head can be removed, so there is no need to remove the burner from the boiler when replacing the nozzle. All conductors are connected in the plug type, and the danger of misconnection is avoided due to the special shape of the mating plugs.