How to calculate the slag and fly ash produced by coal burning?

How to calculate the slag and fly ash produced by coal burning? Coal cinder includes coal ash and slag. When pulverized coal burns in a boiler, it is called fly ash, and the slag discharged from the boiler is called slag.

(1) Slag output:

Glz = b× a× dlz/( 1-clz) where:

Glz- slag output, t/a;

B-coal consumption, t/a;

A-ash content of coal, 20%;

Dlz—— the percentage of ash in slag to total ash in coal combustion, taking 35%;

Clz- combustible content of slag, 20% (10-25%);

(2) Coal ash production:

Gfh = b× a× dfh× η/( 1-cfh) where:

GFH-coal ash output, ton/year;

B—— coal consumption, 800 tons/year;

A-ash content of coal, 20%;

Dfh—— The percentage of ash in smoke and dust in total ash of coal combustion, taking 75%.

(75-85% of pulverized coal furnace); dfh= 1-dlz

η-dust removal rate;

CFH- combustible content in coal ash, 25% (15-45%);

Note: 1) Clz of pulverized coal suspension combustion furnace can be 0-5%; Cf is 15%-45%, and fly ash in thermal power plant is 4%-8%. Clz, Cfh also

It can be selected according to the thermal balance data of the boiler, and can also be obtained by testing in the analysis room.

2) dfh value can be selected according to the boiler balance data, and can also be obtained by looking up the table. When burning coking bituminous coal, lignite or coal slime, the dfh value can be lower, but it can be higher when burning anthracite.

The difference between fly ash and slag 1, slag slag

Also known as slag. The melt floating on the surface of liquid substances such as metals in pyrometallurgical process is mainly composed of oxides (silica, alumina, calcium oxide, magnesium oxide), often containing sulfides and a small amount of metals.

The composition of slag is adjusted by adding proper flux (lime, quartz stone, fluorite, etc.). ). By controlling the composition and properties of slag in smelting process, product gangue and oxidized impurities can be smoothly separated from molten metal or sulfur, harmful impurities in metal can be removed, and nonmetallic inclusions in liquid metal can be absorbed without being directly polluted by furnace gas, thus enriching useful metal oxides; It is also a resistance heater in electric furnace smelting. Slag plays a decisive role in ensuring the smooth progress of smelting, the quality of smelting products and the recovery rate of metal. For example, there is a saying in steelmaking that "the slag is good to make steel".

According to different metallurgical processes, slag can be divided into smelting slag, refining slag and synthetic slag. According to the properties of slag, there are alkaline slag, acidic slag and neutral slag. Many slags have important uses. For example, blast furnace slag can be used as cement raw material; High phosphorus slag can be used as fertilizer; The slag containing vanadium and titanium can be used as raw materials for extracting vanadium and titanium respectively. Some slag can be used to make slag cement, slag brick, slag glass and so on.

2, the formation of fly ash

In the first stage, when pulverized coal starts to burn, the volatile matter with low gasification temperature first escapes from the gap between minerals and solid carbon, making pulverized coal become porous carbon particles. At this time, the particle state of coal ash basically maintains the irregular lump of original coal powder, but due to its porosity, its surface area is large.

In the second stage, with the complete combustion of organic matter in porous carbon particles and the increase of temperature, the minerals in them will also be dehydrated, decomposed and oxidized into inorganic oxides. At this time, coal ash particles will become porous glass body, although its morphology remains basically the same as porous carbon particles, but its specific surface area is obviously smaller than porous carbon particles.

In the third stage, with the progress of combustion, the porous glass gradually melts and shrinks to form particles, and its porosity decreases, roundness increases, and particle size decreases. Finally, the porous glass becomes a dense sphere with higher density and smaller particle size, and the specific surface area of particles decreases to the minimum. There are significant differences in chemical and mineralogical characteristics of ash particles with different particle sizes and densities. Small particles are usually more glassy and chemically active than large particles.

The final fly ash (80% ~ 90% of which is fly ash and 10% ~ 20% is bottom ash) is a complex and changeable multiphase substance with similar appearance and fine and uneven particles. Fly ash is the finest part of the dust entering the flue gas, and bottom ash is the separated coarse particles or slag. These things are heavy, and the burning zone extends to the bottom of the stove.

The above information comes from Baidu, I hope it will help you.

At present, fly ash and slag are the key projects of turning waste into treasure in China, which are widely used in the construction industry.

Baking-free bricks are made of different raw materials and different proportions of raw materials, so there is no difference in the final product quality. There is little difference between compression resistance, antifreeze and waterproof.

What is the difference between fly ash and slag? Fly ash is the fine ash in the flue gas produced by coal combustion (generally referring to the fine ash collected in the flue gas of coal-fired power plants).

Coal cinder is the waste residue discharged by industrial and civil boilers and other devices (mainly coal-fired power plants, gas boilers in fertilizer plants and civil boilers in the north).

1, slag

Also known as slag. The melt floating on the surface of liquid substances such as metals in pyrometallurgical process is mainly composed of oxides (silica, alumina, calcium oxide, magnesium oxide), often containing sulfides and a small amount of metals.

The composition of slag is adjusted by adding proper flux (lime, quartz stone, fluorite, etc.). ). By controlling the composition and properties of slag in smelting process, product gangue and oxidized impurities can be smoothly separated from molten metal or sulfur, harmful impurities in metal can be removed, and nonmetallic inclusions in liquid metal can be absorbed without being directly polluted by furnace gas, thus enriching useful metal oxides; It is also a resistance heater in electric furnace smelting. Slag plays a decisive role in ensuring the smooth progress of smelting, the quality of smelting products and the recovery rate of metal. For example, there is a saying in steelmaking that "the slag is good to make steel".

According to different metallurgical processes, slag can be divided into smelting slag, refining slag and synthetic slag. According to the properties of slag, there are alkaline slag, acidic slag and neutral slag. Many slags have important uses.

2, the formation of fly ash

In the first stage, when pulverized coal starts to burn, the volatile matter with low gasification temperature first escapes from the gap between minerals and solid carbon, making pulverized coal become porous carbon particles. At this time, the particle state of coal ash basically maintains the irregular lump of original coal powder, but due to its porosity, its surface area is large.

In the second stage, with the complete combustion of organic matter in porous carbon particles and the increase of temperature, the minerals in them will also be dehydrated, decomposed and oxidized into inorganic oxides. At this time, coal ash particles will become porous glass body, although its morphology remains basically the same as porous carbon particles, but its specific surface area is obviously smaller than porous carbon particles.

In the third stage, with the progress of combustion, the porous glass gradually melts and shrinks to form particles, and its porosity decreases, roundness increases, and particle size decreases. Finally, the porous glass becomes a dense sphere with higher density and smaller particle size, and the specific surface area of particles decreases to the minimum. There are significant differences in chemical and mineralogical characteristics of ash particles with different particle sizes and densities. Small particles are usually more glassy and chemically active than large particles.

The final fly ash (80% ~ 90% of which is fly ash and 10% ~ 20% is bottom ash) is a complex and changeable multiphase substance with similar appearance and fine and uneven particles. Fly ash is the finest part of the dust entering the flue gas, and bottom ash is the separated coarse particles or slag. These things are heavy, and the burning zone extends to the bottom of the stove.

What is the difference between F-class fly ash and C-class fly ash and 1 class fly ash and 2-class fly ash? Class F: Fly ash collected by burning anthracite or bituminous coal.

Class C: Fly ash collected after lignite or sub-bituminous coal is calcined, and its calcium oxide content is generally greater than 10%.

Grade I: fineness not greater than 12.0% Grade II: not greater than 25.0%.

The water demand is not more than 95%, and the water demand is not more than 105%.

The loss on ignition shall not exceed 5.0%, and the loss on ignition shall not exceed 8.0%.

What fly ash is used for cement precast slab? Is it the fly ash left by coal burning in the power plant? Fly ash can be mixed into cement to make cement precast slab, but it needs very fine fly ash. In the power plant, only the fly ash after the third electric field of electrostatic precipitator can meet the requirements. Therefore, in order to increase income, power plants often set up sorting systems to separate other coal ash, so as to obtain more qualified fly ash.

Does fly ash swell? Fly ash can be used as insulation material instead of slag after being made into blocks or ceramsite.