KR101205146B1 - desulphurizing agent made from by-product of lime cacination and manufacturing method - Google Patents

Abstract

The present invention relates to a method for preparing a desulfurization agent using lime calcined by-products.
The calcined sludge and the analyzed lime are mixed and ground, the calcined lime is mixed, and the water is mixed and stirred.
A slurry desulfurization agent is prepared, and the desulfurization agent is sprayed upward into the adsorption tower 40 to be in contact with the exhaust gas during the desulfurization reaction.
By using the waste calcined by-products, which can be used as a wet desulphurizer, waste emissions are reduced, and energy consumption is reduced because dry grinding is not necessary to reuse the calcined by-products.

Description

Desulphurizing agent made from by-product of lime cacination and manufacturing method

The present invention relates to a method for preparing a desulfurization agent using lime calcined by-products.

The steel mill performs a lime firing process to obtain quicklime for use in steelmaking and steelmaking.

In the calcining process, limestone (calcium carbonate (CaCO ₃ )) is heated while the air is blocked to remove carbon dioxide (CO ₂ ) to prepare quicklime (calcium oxide (CaO)).

An object of the present invention is to provide a method for preparing a desulfurization agent using the lime calcined by-products to recycle the lime calcined byproducts.

Desulfurization agent manufacturing method using a calcined calcined dispersion according to the present invention for achieving the above object, the step of mixing the calcined sludge and analyte, and pulverizing the mixture of the calcined sludge and analyte; Mixing the lime with the pulverized mixture, a water supply step of supplying water to the mixture of the calcined sludge and the analyte and the slaked lime, and a stirring step of mixing the calcined sludge with the analyte and the lime and the water. Characterized in that.

delete

delete

delete

delete

delete

delete

delete

delete

delete

delete

In addition, in the mixing of the calcined sludge with the analysis lime, 20 to 30% of the analyzed lime is mixed with respect to the weight of the calcined sludge, and the mixing of the calcined sludge with 70 to 120% of the calcined lime compared to the weight of the calcined sludge It features.

delete

In addition, the water supply step is characterized in that for supplying water of 75 ~ 85% of the weight of the mixture of the calcined sludge and the analysis lime and slaked lime.

delete

delete

delete

delete

delete

delete

delete

delete

delete

According to the present invention as described above,

Slurry type wet desulphurizer can be prepared by using calcined sludge, analyte and analyte and slaked lime which are by-products of the lime calcining process.

In addition, the sulfur component may be removed from the exhaust gas by contacting the exhaust gas in the absorption tower using the slurry type wet desulfurization agent.

Since it is possible to recycle the waste calcined sludge as described above, there is no need to dry pulverize to use as a lime substitute, thereby reducing energy consumption and reducing waste emissions.

1 is a schematic configuration diagram of an apparatus for producing a desulfurization agent and a flue gas desulfurization apparatus using the desulfurization agent according to the present invention;
2 is a block diagram showing a method for producing a desulfurizing agent according to the present invention;
3 is a block diagram showing a flue gas desulfurization method according to the present invention.

Hereinafter, with reference to the accompanying drawings, the present invention will be described in detail.

Table 1 shows the composition ratio, particle size and specific surface area of the desulfurization agent according to the present invention.

Item
CaO
SiO ₂
Al ₂ O ₃
FeO
Granularity
Specific surface area
Content (dry weight)
58-65%
1-3%
1 ~ 2%
1 ~ 2% 0.15 mm
Below
More than 75% 0.075 mm
Below
More than 40% 10-20
m ² / g

As can be seen in Table 1, the desulfurization agent according to the present invention, CaO (calcium oxide) 58 ~ 65%, SiO ₂ (silicon dioxide) 1 ~ 3%, Al ₂ O ₃ (alumina) 1 ~ 2% by dry weight ratio , FeO (iron oxide) contains 1 ~ 2%, the rest consists of water and impurities.

The impurity consists of C (carbon), MgO (magnesium oxide) and the like.

If the CaO is less than 58%, the desulfurization efficiency is excessively lowered. If the CaO is more than 65%, the desulfurization efficiency is slightly increased, but the increase in desulfurization efficiency is insignificant compared to the increase in content.

In addition, in the case of SiO ₂ , Al ₂ O ₃ , FeO, if the content is less than 1% is excessively low, there is no desulfurization effect, if more than 2% (3% in the case of SiO ₂ ) Ca is the main component of the desulfurization action As the content of the compound decreases and the density of the desulfurization agent increases, the weight increases, so that when it is injected upward in the desulfurization method described later, the drop rate is excessively high and the contact time and the frequency of contact with the exhaust gas are reduced. It is not preferable because it causes a decrease in efficiency.

On the other hand, the desulfurization agent according to the present invention contains 75% or more of particles having a particle size of 0.015 mm or less.

Since a large amount of particles having a small particle size is contained as described above, the specific surface area of the desulfurization agent is increased to improve the desulfurization efficiency.

In particular, the desulfurization agent contains 40% or more of particles having a particle size of 0.075 mm or less.

Since it contains 40% or more of very fine particles as described above, the desulfurization efficiency by increasing the specific surface area is further doubled.

On the contrary, when the particle size is larger than the particle size, the specific surface area of the desulfurization agent decreases, so the desulfurization efficiency is lowered.

In addition, the desulfurization agent according to the present invention has a specific surface area in the range of 10 ~ 20 m ² / g, when the specific surface area of the desulfurization agent is less than 10 m ² / g increases the particle size, the desulfurization efficiency is lowered, 20 m ² / When larger than g, theoretically, the desulfurization efficiency is increased, but it is difficult to prepare the desulfurization agent according to the present invention, which is mainly composed of calcined sludge, to have a larger specific surface area.

Now, a desulfurization agent production method for producing the desulfurization agent according to the present invention will be described.

As shown in Figure 2, the desulfurization agent manufacturing method according to the present invention, the step of mixing the calcined sludge and analyte (S11), the step of grinding the mixture of the calcined sludge and analyte (S12), Mixing the calcined lime with the pulverized mixture (S13), a water supply step of supplying water to the mixture of the calcined sludge and the analyte and the calcined lime (S14), and the calcined sludge with the analyte and the calcined lime and water It includes a stirring step (S15) to mix.

The calcined sludge is generated in the process of removing the fine powder by washing the limestone (raw material of the firing process) in advance in order to secure air permeability in the kiln and prevent the blockage of the pipe during transportation, and dehydrated using a filter press to reduce the volume. Emitted in form.

The lime-fired sludge can be recycled in the sintering and steelmaking process as a limestone substitute because the properties are almost the same as that of limestone, but due to the nature of the sludge, it requires a separate drying and grinding process, which is expensive. Due to the large heat loss, it is now almost discarded.

However, the present invention is very preferable in terms of waste utilization by preparing a desulfurization agent that can be used in wet conditions using the calcined sludge.

On the other hand, the analysis lime and slaked lime are also by-products of the firing process.

In step (S11) of mixing the calcined sludge and the analysis lime, dehydrated in the dehydrator (the filter press) and 20 to 30% of the weight of the calcined sludge discharged in the form of sludge cake. Add limestone to mix.

The calcined sludge discharged from the dehydrator has a water content of 12-16%.

Subsequently, in the step (S12) of crushing the mixture of the calcined sludge and the analyzed lime, the mixture of the calcined sludge and the analyzed lime is put into the grinder 10 (see FIG. 1) and wet-pulverized while supplying moisture.

A ball mill may be used as the grinder.

Subsequently, in step S13 of mixing the calcined mixture with the pulverized mixture, the pulverized mixture is added to the mixing tank 30 and 70 to 120% of the calcined lime is added to the calcined sludge.

Subsequently, in the water supply step (S14) of supplying water to the mixture of calcined sludge and analysis lime and slaked lime, water of 75 to 85% of the weight of the mixture contained in the mixing tank 20 is supplied.

Subsequently, in the stirring step (S15) of mixing the calcined sludge with the analyzed lime and the calcined lime and the water, the calcined sludge, the analyzed lime, the calcined lime and the water contained in the mixing tank 20 are stirred to form a slurry.

The mixing tank 20 is provided with a stirrer 30 for the stirring.

By the production method as described above, a slurry desulfurization agent having a water content of 75 to 85% is produced.

The slurry desulfurization agent is used in the flue gas desulfurization method described later without a separate drying process.

Now, a flue gas desulfurization method according to the present invention will be described.

As shown in FIG. 3 (see FIG. 1 simultaneously), the exhaust gas desulfurization method according to the present invention,

Desulfurizer supply step (S21), exhaust gas introduction step (S22), desulfurization reaction step (S23), and slurry discharge step (S24).

In the desulfurization agent supplying step (S21), the desulfurization agent in the slurry state stirred in the mixing tank 20 is injected into the absorption tower 40 through the desulfurization agent supply pipe 50 and sprayed upward.

A plurality of injection nozzles 41 connected to the desulfurization agent supply pipe 50 are installed on the inner wall of the absorption tower 40, and the injection nozzles 41 are formed with injection holes upward, so that the desulfurization agent in the slurry state is provided. When the pressure is supplied by the pump 35 is injected upward from the injection hole of the injection nozzle 41 into the interior space of the absorption tower 40.

The injected slurry rises by the spraying force as the desulfurizing agent particles are contained in the fine water droplets and then falls to the lower portion of the absorption tower 40 by its own weight.

On the other hand, in the exhaust gas introduction step (S22), the exhaust gas generated in the factory is introduced into the lower portion of the absorption tower 40 by riding the exhaust gas pipe (53).

An diffuser 42 is connected to an end of the exhaust gas pipe 53 inside the absorption tower 40, and the exhaust gas is discharged in a bubble form through the diffuser 42. To this end, the desulfurization agent is preliminarily applied to the lower portion of the absorption tower 40 for a sufficient time so that the desulfurization agent that falls falls to the cover of the diffuser 42. The diffuser 42 is installed in the absorption tower 40 near the bottom.

The exhaust gas discharged from the diffuser 42 moves to the upper portion of the absorption tower 40 and is discharged. In this process, the sulfur component is removed by contact with the desulfurizing agent particles falling.

Since the desulfurization agent is mainly composed of lime, and a large amount of Ca (OH) ₂ (calcium hydroxide) is produced in the water treatment process of the calcined sludge, desulfurization is performed through the following reaction.

Ca (OH) ₂ + CO ₂ → CaCO ₃ + H ₂ O

CaCO ₃ + 2SO2 + H2O → Ca (HSO ₃ ) ₂ + CO ₂

Ca (HSO ₃ 2 + O ₂ + CaCO ₃ + 3H ₂ O → 2 [CaSO _{4 ·} 2H ₂ O] + CO ₂

On the other hand, the slurry collected in the lower absorption tower 40 is discharged to the outside of the absorption tower 40 through the discharge pipe 51 by opening the valve 45 in the slurry discharge step (S24).

As described above, according to the present invention, sulfur components of flue-gases generated in steel mills and incinerators using slurry type wet desulphurizers prepared by mixing previously disposed lime-fired sludge and analytical lime and slaked lime which are by-products of another firing process. Can be removed.

On the other hand, the present invention may further include a sludge settling step (S25), a sludge dewatering step (S26) and a dewatered sludge discharge step (S27) after the slurry discharge step (S26).

The sludge precipitation step (S25) discharges the slurry discharged through the discharge pipe 51 in the slurry discharge step (S26) to the precipitation tank 60 to precipitate the sludge as a solid component in the slurry in the precipitation tank (60).

Subsequently, in the sludge dehydration step (S26), the sludge precipitated in the settling tank 60 is supplied to the dehydrator 90 to dehydrate the sludge.

Subsequently, the dewatered sludge is discharged from the dehydrator 90 in the dewatered sludge discharge step (S27).

The discharged sludge can be recycled as a gypsum substitute.

On the other hand, the present invention may perform a supernatant reuse step (S28) after the sludge precipitation step (S25).

In the supernatant using step (S28), the supernatant separated from the sludge in the sedimentation tank 60 is supplied back to the mixing tank 20 through a water supplement pipe 52 to supply water before stirring in the mixing tank 20. It can be used when performing (S14).

Since the lime component is dissolved in the supernatant, the desulfurization agent is more smoothly and easily made.

10: grinder 20: mixing tank
30: stirrer 35: pump
40: adsorption tower 41: injection nozzle
42: diffuser 45: valve
50: desulfurization supply pipe 51: discharge pipe
52: water supplement pipe 53: exhaust gas pipe
60: sedimentation tank 70: dehydrator

Claims (10)

delete delete delete delete Mixing the calcined sludge with analyte (S11),
Pulverizing the mixture of the calcined sludge and analyte (S12),
Mixing the lime with the ground mixture (S13);
Water supply step (S14) for supplying water to the mixture of the calcined sludge and analysis lime and slaked lime,
Method for producing a desulfurization agent using a calcined calcined by-product comprising the stirring step (S15) of mixing the calcined sludge with analytical lime, slaked lime and water. The method according to claim 5,
In the step of mixing calcined sludge and analyte lime (S11), 20 to 30% of analyte lime is mixed with respect to the weight of calcined sludge,
Method for producing a desulfurization agent using lime calcined by-products, characterized in that the calcined lime mixing step (S13) to mix the calcined lime of 70 to 120% by weight of the calcined sludge. The method according to claim 5,
Method for producing a desulfurization agent using lime calcined by-products, characterized in that for supplying water 75 to 85% of the weight of the mixture of the calcined sludge and the analysis lime and slaked lime in the water supply step (S14). delete delete delete

Images