JPS5913246B2 - Method for reducing harmful components in exhaust gas emitted from cement firing equipment with dry boiler - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for simultaneously reducing both nitrogen oxides (NOx) and sulfur oxides (SOx) in exhaust gas discharged from a cement firing apparatus with a dry boiler.

More specifically, the present invention provides a method for firing cement raw materials in a firing furnace of a cement firing apparatus equipped with a dry boiler.
The ratio (A/Ao) between the amount of air entering the kiln A and the theoretical amount Ao of air required for complete combustion of the fuel is (1+1.5 D)
(In this formula, D is the inner diameter of the firing furnace 00 m.) Adjust the exhaust fan installed between the boiler water pipe and the electrostatic precipitator so that the distance between the kiln bottom of the firing furnace and the boiler water pipe is The amount of suspended dust in the exhaust gas in the dust chamber provided at
Ammonia and/or a compound that generates ammonia is blown into the exhaust gas at 800 to 1100°C in the dust chamber and/or the bottom of the kiln of the kiln, and the ammonia and/or ammonia is
The present invention also relates to a method for reducing nitrogen oxides and sulfur oxides, which are harmful components in the exhaust gas discharged from a cement firing apparatus with a dry boiler, which is characterized by consuming compounds that generate ammonia.

In recent years, from the perspective of air pollution, research has become active on ways to remove or reduce harmful components such as SOx and NOx from exhaust gas emitted from various chemical plants and factories, and many proposals have already been made. However, there are few proposals regarding methods for removing or reducing harmful components emitted from cement firing equipment.

Conventionally, methods for reducing harmful components, especially NOx, in exhaust gas emitted from cement firing equipment are disclosed in Japanese Patent Application Laid-Open No. 52-10320 and Japanese Patent Application Laid-Open No. 52-14619.
It is stated in the No.

The methods described in these publications include JP-A-48-40805, JP-A-50-7774, and JP-A-50-35.
Application of the method of reducing NOx in the exhaust gas by introducing ammonia or a compound that generates ammonia into the exhaust gas, which is described in Japanese Patent Application Laid-Open No. 50-153762, Japanese Patent Application Laid-Open No. 51-20771, etc. Both relate to a method of reducing NOx in exhaust gas discharged from a cement firing apparatus with a suspension preheater.

However, no effective method has yet been proposed for removing or reducing harmful components in the exhaust gas discharged from a cement firing apparatus with a dry boiler.

In a dry type boiler-equipped cement firing apparatus, generally, as shown in the schematic cross-sectional view of Fig. 1, cement raw materials are fed into a firing furnace (rotary kiln) 1 through a raw material feed chute 2, and heavy oil is fed into a rotary kiln 1 through a raw material feed chute 2. Fuel, primary air, and secondary air are introduced, the fuel is combusted in burner 3, and cement raw materials are fired at approximately 1450°C in kiln 1 to produce clinker, but exhaust gas is generated at this time. The exhaust gas is drawn by the exhaust fan 7, passes through the dust chamber 8 from the bottom of the kiln of the kiln 1, and is led to the boiler water pipe 9 for exhaust heat recovery, and then to the electrostatic precipitator 10 and the chimney 11.
The system is different from that of a cement firing apparatus with a suspension preheater in that the exhaust gas contains a considerable amount of SOx as well as NOx.

Cement firing equipment with suspension preheater
Since exhaust heat recovery is performed using a multi-stage cyclone instead of the boiler water tube in the dry boiler-equipped cement firing equipment, SOx in the exhaust gas generated in the firing furnace reacts with the cement raw material and is absorbed when it passes through the cyclone.

However, since a dry boiler-equipped cement firing apparatus is not equipped with a cyclone, the exhaust gas released into the atmosphere contains a considerable amount of SOx as well as NOx.

Therefore, in a cement firing apparatus with a dry boiler, it is necessary to remove or reduce SOx as well as NOx, and it is not possible to remove or reduce both at the same time by simply applying conventionally known methods.

Conventionally, methods for reducing SOx in the exhaust gas emitted from a cement firing equipment with a dry boiler include (a) a method of modifying the equipment to a cement firing equipment with a suspension preheater, (a method of installing a zero smoke desulfurization equipment, (c) Methods such as using low-sulfur fuel are being considered, but ((
) method has problems such as modification costs, electric power, and location conditions, and method (f)) has problems such as desulfurization cost, processing of by-products, and large equipment, and e→
This method has problems such as fuel cost and energy situation, and no method or solution that is satisfactory in terms of both SOx reduction effect and economical efficiency has yet been found.

In addition, as methods for reducing NOx in the exhaust gas emitted from cement firing equipment with a dry boiler, methods such as 0) changing combustion conditions and IF smoke denitrification methods are being considered.
Methods a) include the two-stage combustion method, the exhaust gas recirculation method, and the low-oxygen firing method. The low-oxygen firing method does not have the expected effect of reducing NOx, and in order to suppress the amount of NOx produced, the oxygen concentration is lower than the current level (necessary for complete combustion of the fuel). (approximately 1.02 times the theoretical air amount or less), the operation of the kiln becomes unstable, resulting in a decrease in cement production and cement quality, as well as a sharp increase in the SOx concentration in the exhaust gas. There is.

In addition, exhaust gas denitrification methods include a catalytic reduction method that reduces and decomposes NOx in exhaust gas in the presence of a catalyst, a wet absorption method that absorbs and removes NOx with various absorption liquids, and a catalyst that uses a catalyst for high-temperature exhaust gas. NO by adding a reducing substance such as ammonia.
There are methods such as the direct reductive decomposition of However, the wet absorption method has problems such as post-treatment of the absorbent used, treatment of by-products, and denitrification costs.

Regarding the non-catalytic NH3 method, as mentioned above, if most of the harmful components in the exhaust gas are NOx, as in the case of cement firing equipment with a suspension preheater, there is no need to particularly consider SOx; It is necessary to remove or reduce SOx as well as NOx from the exhaust gas from the equipment, and in the case of a cement firing equipment with a dry boiler, unlike the case of a cement firing equipment with a suspension preheater, there is no cyclone or calciner, and it is necessary to remove ammonia from the exhaust gas. There is not enough space to fully inject and mix the ammonia in two stages, and in cement firing equipment with a dry boiler, exhaust heat is recovered using boiler water pipes rather than cyclones, so the water pipes are used as oxidation catalysts for the ammonia blown into the cement firing equipment. acts as a NOx
By simply blowing in ammonia, it is not possible to remove or reduce both NOx and SOx at the same time.

The inventors have conducted intensive research on a method for simultaneously removing or reducing both NOx and SOx, which are harmful components in the exhaust gas from a cement firing apparatus with a dry boiler.

As a result, the amount of air A (Nm3/
By adjusting p) for the fuel, the amount of air entering the kiln A and the theoretical amount of air required to completely burn the fuel Ao (Nm”/
When the ratio A/Ao (combustion air ratio) of fuel to 9) is set to a predetermined value M or more, both NOx and SOx in the exhaust gas are significantly reduced when ammonia is injected into the exhaust gas, and the predetermined value M is closely related to the inner diameter D (c) of the firing furnace, and the following relationship exists between the predetermined value M and the inner diameter of the furnace 0. It is necessary to select the location where ammonia and/or the compound that generates ammonia will be injected, and in this case, the amount of suspended dust in the exhaust gas discharged from the kiln, the exhaust gas temperature, etc. We came to this invention after learning that it is necessary to take these into account.

This invention is based on the ratio (A/ Adjust the exhaust fan installed between the boiler water pipe and the electrostatic precipitator so that Ao) is at least (1 + 101) [in this formula, D is the inner diameter m of the firing furnace], and then The amount of suspended dust in the exhaust gas in the dust chamber provided between the butt and the boiler water pipe can be reduced from 0.1 to 0.1, mainly by adjusting the rotation speed of the exhaust fan.
97N to 0.6, 8 to 97N, dust chamber and/or
Or, blowing ammonia and/or an ammonia-generating compound into the exhaust gas at 800 to 1100°C in the kiln bottom of the kiln, and consuming the ammonia and/or the ammonia-generating compound in the kiln bottom or dust chamber of the kiln. This invention relates to a method for reducing nitrogen oxides and sulfur oxides, which are harmful components in the exhaust gas discharged from a cement firing device with a dry boiler, and the method of the present invention has the ability to reduce compared to conventionally known methods. It has the following advantages:

(1) Comparison with conventionally known SOx reduction methods Modifying a cement firing equipment with a suspension preheater or installing a flue gas desulfurization equipment requires enormous equipment costs and expenses, but the method of the present invention It is possible to reduce SOx without any modification or installation of a desulfurization device, and there is no need to particularly consider processing of by-products or fuel issues.

(2) Comparison with conventionally known NOx reduction methods With the method of the present invention, the kiln can be operated under almost conventional conditions, resulting in lower cement production and lower cement quality than in the case of the low-oxygen calcination method. It is possible to avoid troubles in the operation of the kiln and increase in SOx concentration in the exhaust gas, and because it does not use a catalyst like the catalytic reduction method, there are no associated troubles, and it uses an absorption liquid like the wet absorption method. There's no need to.

Also, unlike cement firing equipment with a suspension preheater, cement firing equipment with a dry boiler has equipment limitations and problems such as SOx as described above, making it difficult to apply the non-catalytic NH3 method. However,
According to the method of this invention, it is possible to effectively reduce not only NOx but also SOx in exhaust gas easily and at low cost. It is better than what would happen if the law were applied.

The method of the present invention will be explained with reference to a schematic sectional view of a cement firing apparatus with a dry boiler shown in FIG.

In this invention, the amount of air entering the firing furnace 1 [the total amount of primary air and secondary air A (N), the amount of theoretical air necessary for complete combustion of the twisting material, and the fuel fed into the firing furnace 1. Amount Ao (N
The boiler water pipe 9 and the electrostatic precipitator 10 are connected so that the ratio (A/Ao) to (m3/Kg of fuel) is at least (1+±) (in this equation, D is the inner diameter of the firing furnace 1, 00 m). It is important to adjust the exhaust fan 7 provided between the two.

Adjustment of the exhaust fan 7 can be easily carried out, for example, by increasing the rotation speed of the exhaust fan 7 by a factor of 10 to 20 or more over the rotation speed during conventional normal operation.

Air amount A entering the firing furnace 1 and the theoretical air amount A.

When the ratio (A/Ao) is smaller than (1+1.5D), the dust concentration in the exhaust gas becomes low and the SO
The content of The denitrification rate and denitrification rate are low, and the effect of reducing SOx and NOx in exhaust gas is not significant.

The upper limit of the air amount A entering the firing furnace 1 is not particularly limited, but if the air amount A becomes too large, the amount of exhaust gas will increase, and the amount of suspended dust in the exhaust gas will become excessive, resulting in SO
Although the desulfurization rate of x increases, the reaction between 0□ and NH3 in the exhaust gas is promoted and the denitrification rate not only decreases, but also causes problems such as maintaining the temperature of the kiln 1 and increasing the amount of ammonia used. Therefore, it is preferable that the value of (1+ri) does not become larger than 12, although it varies depending on the inner diameter of the firing furnace 1.

By adjusting the amount of air A that enters the kiln 1 with the exhaust fan 7, the SO2 produced by the combustion of cement raw materials, cement dust, and fuel (sulfur-containing heavy oil) can be removed in the kiln 1 and in the dust chamber 8. is the following formula: CaO+SO2+-H02-CaSO4 The desulfurization reaction progresses and SOx in the exhaust gas is reduced.

This desulfurization reaction becomes more pronounced as the 0□ concentration in the reaction system increases, and conversely, when the 0□ concentration is low and the temperature of the reaction system rises, the decomposition reaction of the generated CaSO4 progresses and the SO
It generates x.

Regarding NOx in the exhaust gas, suspended dust in the exhaust gas acts as a mixing medium and catalyst, promoting the mixing and diffusion of the injected ammonia and the exhaust gas, and the reaction between the ammonia and the NOx in the exhaust gas is effective. It is thought that this progresses and the amount of NOx in the exhaust gas decreases.

In the method of this invention, the amount of suspended dust in the exhaust gas in the dust chamber 8 is 97N@
``Preferably 0.2 to 0.5 Ky/Nm3.

If the amount of suspended dust is less than 0.1 K97 Nm3, the injected ammonia will not react sufficiently with NOx in the bottom of the kiln 1 or in the dust chamber 8 and will remain unconsumed and will be entrained in the exhaust gas and sent to the boiler. The ammonia reaches the water pipe 9 and not only contacts the boiler water pipe and is oxidized to NOx, but also has little effect as a mixing medium, which is undesirable because denitrification becomes poor.

In addition, when the amount of suspended dust exceeds 0.6 K97 Nm3, ammonia consumption reaction occurs, 4NH3 + 30□ → 6
H20+2N2 becomes significant and the denitrification rate decreases, which is not preferable.

The amount of suspended dust can be adjusted mainly by adjusting the rotation speed of the exhaust fan 7, and also by adjusting the rotation speed of the firing furnace 1 as needed, or by adjusting the rotation speed of the firing furnace 1 as needed. This is done by modifying the bottom of the kiln 1 and the outlet of the raw material feed chute 2.

In the method of the present invention, ammonia is suitably injected into the kiln bottom and/or dust chamber 8 of the kiln 1, and the kiln 1 is located as far away from the boiler water pipe 9 as possible.
The ammonia blowing pipe 12 is preferably located near the raw material feed chute 2 at the bottom of the kiln of the kiln 1 and/or near the exhaust gas outlet of the kiln 1.

The purpose of blowing ammonia can be achieved sufficiently by blowing from one place using only the raw material feed chute or one blowing pipe, but it is also possible to blow ammonia from two or more places. You can also blow it in through the blowpipe.

As the ammonia blowing pipe 12, a pipe with a water cooling sleeve as shown in FIGS. 2 and 3 is suitable. The pipe in FIG. Water is supplied from the arrow 2 and blown from the tip A of the ammonia supply pipe 13, and water is supplied from the arrow 2 and discharged from the arrow 3 in order to prevent the ammonia from decomposing.

The pipe in Fig. 3 consists of an ammonia supply pipe 15, a cooling pipe 16, and a cleaning pipe 17. Ammonia is supplied from arrow 4, water is supplied from arrow 5 to prevent decomposition of ammonia, and water is discharged from arrow 6. When the tag or dust adheres to the tip of the ammonia supply pipe 15, it can be cleaned by supplying water, air, steam, etc. from the arrow T in order to clean it.

By blowing ammonia into the dust chamber 8 and/or the bottom of the firing furnace 1, NOx and ammonia in the exhaust gas are calculated by the following formula: 4NO+4NH3+02→6H20+4N26NO+4
It is thought that the denitrification reaction progresses by NH3→6H20+5N2.

The form of ammonia used for blowing is gas, liquid,
It may be in any form such as an aqueous solution, and it is generally convenient to use it in a gaseous form, or it may be used after being diluted with water vapor, nitrogen, or the like.

In addition, although ammonia is generally preferred for blowing, a compound that generates ammonia when heated in the reaction system may be used instead of ammonia, or ammonia and a compound that generates ammonia may be used in combination. You may do so.

Compounds that generate ammonia include, for example, ammonium carbonate, ammonium hydrogen carbonate, ammonium sulfate,
Mention may be made of ammonia derivatives such as urea, ammonium carbamate, ammonium oxalate, ammonium formate, and hydroxylamine.

In the method of this invention, the amount of ammonia blown is N
It may be determined according to the degree of Ox emission regulation, but it is usually 0.5 per mole of NOx in the exhaust gas from the firing furnace 1.
A suitable amount is mol or more, preferably about 0.75 to 4 mol.

Note that even if 1 mol or more is injected, the rate of improvement in the denitrification rate is small.

If the amount of ammonia blown in is less than 0.5 mol, the denitrification rate will be low, and if the amount of ammonia blown in is too large, the amount of ammonia blown in will vary depending on the amount of suspended dust in the exhaust gas, the oxygen content, etc. Ammonia is in the kiln 1
This is because the ammonia is not completely consumed in the bottom of the kiln or in the dust chamber 8 and remains in the boiler water pipe 9 and comes into contact with the water pipe, where it is oxidized to NOx or leads to an increase in the amount of ammonia used due to the ammonia consumption reaction as described above. ,NOx
About 1 mol of ammonia per 1 mol is sufficient.

When a compound that generates ammonia is injected as ammonia, the amount of ammonia injected is within the above range in terms of NH.

In the method of this invention, the ammonia flow velocity at the tip of the ammonia blowing pipe is set to 200 m/sec or more,
Preferably, ammonia is blown into the furnace at a temperature of 220 to 300 m//SeC, or blades 18 as shown in FIGS. Providing a wall 19 as shown in FIG. 6 downward from the ceiling of the dust chamber 8 has the great effect of improving the denitrification rate, especially at an NH3/NOx molar ratio of 1.0 or less.

The vanes and walls are preferably made of firebrick.

When the firing furnace 1 is provided with blades, it is preferable to provide approximately 6 to 12 blades at an angle of -15 to 45 degrees in the circumferential direction of the firing furnace 1.

In addition, if a wall is provided from the ceiling of the dust chamber 8, the D/
At least one wall with a length extending downward from the ceiling at a distance of 2 to D [D is the inner diameter m of the firing furnace 1] to reach an extension of the central axis P of the firing furnace 1, preferably 1 to Three plates are provided, and an ammonia blowing pipe 12 is installed between the firing furnace 1 and the wall.
It is good to have a

It is thought that by providing such blades and walls, the flow of the exhaust gas is disturbed and the mixture of the exhaust gas and ammonia is improved, thereby improving the denitrification rate.

In the method of this invention, the contact humidity between ammonia and exhaust gas is 800 to 1100°C, preferably 900 to 1
If the exhaust gas temperature is lower than 800°C, the denitrification reaction will not be sufficiently promoted, and if it is higher than 1100°C, ammonia will be oxidized to NOx and the denitrification rate will decrease, which is not preferable.

According to the method of the invention, the blown ammonia is almost completely consumed before it reaches the boiler water pipe 9.

Another great feature is that both SOx and NOx in the exhaust gas can be significantly reduced at the same time without significantly modifying the conventional dry boiler-equipped cement firing apparatus.

Next, examples and comparative examples will be shown to provide a detailed explanation of the present invention.

The denitrification rate and the denitrification rate in each example are in accordance with the following - Examples 1 to 4 and Comparative Examples 1 to 2 Size: 85m1 Cement clinker - firing rate: 40t/hr, usage of heavy oil with 2.3% sulfur content: 6Kl/hr, theoretical exhaust gas volume from the kiln end: 77,00
0 Nm3/hr), the number of revolutions of the exhaust fan was varied as shown in Table 1 to calculate the amount of air A that enters the kiln and the theoretical amount A of air required for complete combustion of fuel (heavy oil).
o (combustion** air ratio) A/Ao as shown in Table 1, and the end of the firing furnace (dust chamber side at the bottom of the kiln)
An ammonia blowing pipe of the same type as the one shown in Figure 2 was installed 1.5 m away from the furnace so that it penetrated the ceiling of the dust chamber and reached the inside of the dust chamber. Gaseous ammonia was blown into the reactor at a flow rate of 38 m/SeC at a rate of 1 mol per mol of NOx in the exhaust gas.

As a result, the SOx concentration, NOx concentration, desulfurization rate, and denitrification rate in the flue gas discharged from the chimney were as shown in Table 1.

From this Table 1, it can be seen that the amount of air entering the kiln by the exhaust fan is adjusted according to the method of the present invention, and A/A is obtained.

It can be seen that when 1.06 or more, SOx and NOx in the flue gas are significantly reduced compared to the conventional case (corresponding to Comparative Example 2).

In addition, although the amount of ammonia injected was the same as in Example 2, only the number of ammonia injection pipes was changed from one to two, but the results were almost the same as in Example 2, so the description will be omitted. .

Examples 5 to 7 and Comparative Examples 3 to 4 Using the same kiln as in Example 1, by changing the amount of heavy oil used, the amount of clinker burned out, and the rotation speed of the exhaust fan, the kiln bottom exhaust gas temperature was adjusted to the temperature shown in Table 2. The combustion air ratio was fixed at 1.08 as in Example 2, and ammonia gas was blown in the same manner as in Example 2 at a rate of 1 mole of NOx in the exhaust gas from the bottom of the kiln.

As a result, the desulfurization rate was about 90 in all cases, and the denitrification rate was as shown in Table 2.

From Table 2, even if the fuel-air ratio (A/Ao) is within the range of this invention, if the temperature when blowing ammonia is too low or too high, both SOx and NOx cannot be reduced at the same time. I understand that.

Examples 8 to 11 and Comparative Examples 5 to 6 A firing furnace with an inner diameter of 2.5 m was used, and Example **1
In the same way as in ~4, the rotation speed of the exhaust fan was changed and the combustion air ratio (A/Ao) was changed as shown in Table 3. Ammonia gas was blown into the dust chamber at a flow rate of 38 m/sec at a rate of 1 mol.

The results are shown in Table 3. From Table 3, the inner diameter of the firing furnace is 2
．． In the case of 5 m, it is found that the combustion air ratio (A/Ao) needs to be 1.04 or more, and from Tables 1 and 3, the inner diameter Dfr1) of the firing furnace and the combustion air ratio (A/Ao)
The relationship M=1+±5D holds true with the lower limit (goods) of .

00 Examples 12-13 The amount of ammonia blown was determined by adjusting the amount of ammonia injected into the
An attempt was made to reduce SOx and NOx in the exhaust gas in the same manner as in Example 2, except that x (concentration: 830 ppIn) was changed to 1.5 mol and 2.0 mol per mol.

The results are shown in Table 4. In addition, S in the flue gas
Regarding the Ox concentration, the results were almost the same as in Example 2 (130 ppm), so the description will be omitted.

Comparative Examples 7-8 The same procedure as Comparative Example 2 was carried out, except that the amount of ammonia blown was changed to 1.5 mol and 2.0 mol per mol of NOx in the kiln bottom exhaust gas as in Examples 12-13. Attempts were made to reduce SOx and NOx in exhaust gas.

The results are shown in Table 4. In addition, SOx in flue gas
Regarding the concentration, the results were almost the same as those of Comparative Example 2 (850 ppm), so the description will be omitted.

Examples 14 to 24 Inside the end of the firing furnace of Example 1 (on the dust chamber side of the bottom of the kiln), a refractory brick blade with a height of soom, a thickness of 200M, and a length of 800M was installed in the circumferential direction of the firing furnace. 30°
6 pieces should be installed at equal intervals so that the angle of 6 o of 2) Install one sheet vertically until it reaches the extension of the central axis of the firing furnace, or furthermore, install both blades and walls to remove the exhaust gas from the bottom of the firing furnace (temperature approximately 940℃, NOx NOx1 in concentration 830 Wm1 suspended dust amount 0.3 Ky/N7713)
Add ammonia at a rate of 0.75 mol or 1.0 mol per mol, and
Ammonia was blown into the dust chamber at the flow rate shown in Table *5 from a single ammonia blowing pipe that was inserted through the ceiling of the dust chamber at a distance of m.

Note that the combustion air ratio (A/Ao) was 1.08.

Table 5 shows the results.

The result when neither the blade nor the wall is provided is also the same as the fifth one.
Shown in the table.

The desulfurization rate was 90% in all cases.

[Brief explanation of drawings]

FIG. 1 is a schematic sectional view of a cement firing apparatus with a dry boiler, FIG. 2 is a schematic sectional view of one embodiment of the ammonia blowing pipe, and FIG. 3 is a schematic sectional view of another embodiment of the ammonia blowing pipe. Figure 4 is a schematic cross-sectional view of the end of the firing furnace when blades are provided on the inner surface of the end of the furnace, and Figure 5 is a cross-sectional view along line AA' of Figure 4 when six blades are installed. 1 is a schematic cross-sectional view of a dust chamber when a wall is provided in the dust chamber. 1...Calcination furnace, 2...Raw material feed chute, 3...Burner, 4...Fuel supply pipe, 5...1 Next air supply pipe, 6...2
Next air inlet, 7...exhaust fan, 8...
...Dust chamber, 9...Boiler water pipe,
10...Electric precipitator, 11...Chimney,
12... Ammonia blowing pipe, 13...
... Ammonia supply pipe, 14 ... Cooling pipe, 15
......Ammonia supply pipe, 16...Cooling pipe, 17...Cleaning pipe, 18...Blade,
19... Wall.

Claims (1)

[Scope of Claims] 1. When cement raw materials are fired in the furnace of a cement firing apparatus with a dry boiler, the ratio of the amount of air A that enters the furnace to the theoretical amount of air 1.5D Ao required for complete combustion of fuel ( A/Ao) is (1+TTT) [In this formula, D
is the inner diameter of the firing furnace).Adjust the exhaust fan installed between the boiler water pipe and the electrostatic precipitator so that the dust The amount of suspended dust in the exhaust gas in the chamber can be adjusted to 0.1 to 0.0 by adjusting the rotation speed of the exhaust fan.
6 Ky/N7713, ammonia and/or a compound that generates ammonia is blown into the exhaust gas at 800 to 1100°C in the dust chamber and/or the bottom of the kiln of the kiln, and the ammonia and/or A method for reducing nitrogen oxides and sulfur oxides, which are harmful components in the exhaust gas discharged from a cement firing equipment with a dry boiler, which is characterized by consuming compounds that generate ammonia.