KR101053386B1 - Quicklime manufacturing method and apparatus - Google Patents

Abstract

The present invention relates to a method and apparatus for preparing quicklime.

The present invention comprises the steps of separating the rotary kiln into a primary kiln and a secondary kiln; Mounting a burner using pulverized coal and COG gas as a mixed fuel in a secondary kiln, and installing a burner using only COG gas as a fuel in a secondary kiln; Preheating the limestone by inputting 80 to 85% of pulverized coal and COG gas to the preheater and the primary kiln, and the secondary kiln and the cooler to 15 to 20% of the COG gas to the total amount of fuel used. It provides a method and apparatus for blowing pulverized coal comprising a multi-stage rotary firing furnace comprising the step of firing limestone into quicklime. According to the present invention, a mixture of pulverized coal and COG gas is used as a fuel for a rotary kiln, but the primary kiln and the secondary kiln are divided and the primary kiln is mainly used for preheating limestone by mixing and using pulverized coal and COG gas. In the secondary kiln, only the COG gas is used to burn unburned pulverized coal, as well as calcining limestone to be produced as a quicklime product, thereby improving the product quality.

Preheater, limestone, rotary kiln, quicklime, pulverized coal blown, COG gas

Description

Method and apparatus for preparing quicklime {METHOD AND APPARATUS FOR MANUFACTURING QUICKLIME}

1 is a block diagram showing an overall device for implementing the method for producing quicklime according to the present invention;

2 is an explanatory diagram showing primary and secondary firing furnaces provided in the quicklime manufacturing apparatus according to the present invention;

3 is a longitudinal sectional view showing a pulverized coal injection burner provided in a primary firing furnace equipped with a quicklime producing device according to the present invention;

4 is a detailed view of the pulverized coal injection burner shown in FIG.

         a) is a sectional front view of the flow path, and b) is a side sectional view of the flow path;

5 is a longitudinal sectional view showing a COG gas burner provided in a secondary kiln equipped with a quicklime producing device according to the present invention;

6 is a detailed view of the COG gas burner shown in FIG.

         a) is a sectional front view of the flow path, and b) is a side sectional view of the flow path;

7 is a block diagram showing an apparatus for producing quicklime according to the prior art.

       <Description of the symbols for the main parts of the drawings>

10 .... Primary firing furnace 20 .... Pulverized coal blowing burner                 

22 .... Pulverized coal blower 22a .... Vortex

24,28 .... combustion gas pipe 26 .... COG gas pipe

30 .... Secondary kiln 40 .... COG gas burner

200 .... Quicklime Making Equipment 205 .... Firing Furnace

210 .... preheater 220 .... burner

209 .... Charging hopper 210 .... Pre-heater

222 .... outlet 230 .... cooler

250 .... dust collector 260 .... stack

The present invention relates to a method and apparatus for preparing quicklime, and more specifically, to use a mixture of pulverized coal and COG gas as a fuel for a rotary kiln, and to separate the primary and secondary kilns in the primary kiln, the mixture of pulverized coal and COG gas. It is mainly used for preheating limestone. Secondary kiln is used to burn unburned pulverized coal using only COG gas, as well as calcined limestone to be produced as quicklime product. The present invention relates to a method and apparatus for blowing pulverized coal in a kiln.

In general, the conventional quicklime manufacturing apparatus 200 provided in an ironworks is provided with a preheater 210 on one side of the firing furnace 205, and passes through the preheater 210 as shown in FIG. 7. Limestone (CaCO ₃ ) is charged into. And, the kiln 205 is

The burner 220 is provided on the opposite side of the preheater 210, and an outlet 222 is formed on the lower side thereof to discharge the quicklime (CaO) from which calcining is completed.

In addition, the outlet 222 is provided with a cooler 230 for cooling the quicklime, and the calcining furnace 205 is rotated and calcined into the quicklime by the heat source of the burner 220 while the limestone contained therein is rotated.

Such quicklime manufacturing apparatus 200 is the quicklime manufacturing process is as follows. That is, after limestone is cleanly washed in a separate centuries (not shown), and then sorted into granules having a size of 10 to 30 mm, charged into a kiln pre-heater 210 from the charging hopper 209, After preserving for about 9 to 10 hours and preheated with the exhaust gas of about 1000 ~ 1100 ℃ discharged from the kiln 205, the exhaust gas is discharged to the stack 260 through the dust collector 250, limestone in the preheated state It charges into the rotary kiln 205 in the direction opposite to the discharge direction of waste gas.

   In the rotary kiln 205, the limestone preheated to a predetermined temperature is heated. Thus, the burner 220 burns fuel to generate hot combustion gas, and the inside of the kiln 205 is 1250 to 1300. Limestone is fired while rotating the firing furnace 205 at a temperature of 2.5 ° C. for 3 hours. Then, the quicklime is taken out from the kiln 205, charged in the cooler 230, and cooled for 2 to 3 hours to produce the final product (quicklime).                         

   The conventional rotary kiln 205 is very advantageous in producing high quality quicklime compared to the linear kiln 205 in which limestone is not rotated because limestone is uniformly heated by rotation.

However, in the conventional rotary kiln 200 as described above, when the amount of pulverized coal ejected and combusted from the pulverized coal blowing burner 220 uses 20% or more of the amount of COG gas, the COG gas and the pulverized coal of the burner 220 are used. When the fuel is ejected from the outlet and reaches the combustion section of the kiln, the highest flame part of the COG gas flame is completely burned at the combustion point of the kiln to burn the raw stone (limestone) inside the kiln, but some of the pulverized coal is due to the characteristics of the solid. During the preheating process, it falls down by its own weight and burns.

In addition, some of the pulverized coal is flowed backward in the reverse direction of the tip of the burner 220 and flows into the cooler 230 in which the product is stored, and the unburned pulverized coal is burned in the cooler 230. This results in the effect of absorbing unnecessary heat to the quicklime product that needs to be completely calcined and cooled, and this additional combustion action causes the undercurrent of the quicklime product (black burning and differentiation), leading to poor quality. It causes a problem.

Therefore, in order to reach the preheating and combustion section of the pulverized coal in the firing furnace 200 according to the related art, the injection amount and the injection speed of the pulverized coal blowing air are increased, and when the pulverized coal is injected by 20% or more with respect to the COG gas amount, The outside of the quicklime product was underestimated and the inside was not fired, resulting in quality defects. As such, the pulverized coal blown calcining furnace according to the prior art has a problem in that the use of pulverized coal is set at a certain limit (20% or less), and mixed with COG gas according to the ratio.

Therefore, the amount of pulverized coal is limited, and accordingly, the amount of COG gas is increased, thereby limiting the reduction in manufacturing cost.

The present invention is to solve the conventional problems as described above, the purpose is to divide the firing furnace into primary and secondary firing furnace, in the primary firing furnace to use the pulverized coal and COG gas to achieve the preheating of limestone as a raw material In the secondary kiln, the COG gas burner, which does not take pulverized coal, is fired to burn unbaked raw materials into quicklime to prevent underdevelopment, thereby increasing the use ratio of pulverized coal to COG gas, thereby reducing the production cost of the product. Of course, there is provided an improved method for producing quick lime to improve the amount and quality of quick lime produced as a finished product.

In order to achieve the above object, the present invention, in the limestone manufacturing method for blowing the pulverized coal as a heat source from the limestone provided from the preheater and firing it in quicklime inside the rotary kiln, and discharged through the cooler,

Dividing the rotary kiln into a primary kiln and a secondary kiln;

Mounting a burner using pulverized coal and COG gas as a mixed fuel in the primary kiln, and installing a burner using only COG gas as fuel in the secondary kiln;

Preheating limestone by inputting 80-85% of pulverized coal and COG gas to the preheater and the primary firing furnace; and,

By calcining limestone into quicklime by injecting COG gas of 15 to 20% of the total amount of fuel used in the secondary kiln and the cooler; by providing a method for producing quicklime.

In the present invention, in the limestone manufacturing apparatus which blows pulverized coal as a heat source from limestone provided from a preheater, calcinates it into quicklime inside a rotary kiln, and discharges it through a cooler,

A primary firing furnace located at a rear side of the preheater to receive preheated limestone;

Pulverized coal injection burner for pre-heating limestone by injecting pulverized coal and COG gas of 80 ~ 85% of the total fuel used to provide a heat source to the primary kiln;

A secondary kiln connected to the primary kiln in series through a chute and receiving preheated limestone; and

It is to provide a quicklime manufacturing apparatus comprising a; a COG gas burner for firing limestone into quicklime by injecting COG gas of 15-20% of the total amount of fuel used to provide a heat source to the secondary kiln.

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

The method for producing quicklime according to the present invention includes first separating the rotary kiln into a primary firing furnace 10 and a secondary firing furnace 30.

In the present invention, limestone is introduced into rotary kilns 10 and 30 divided into 1st and 2nd stages, so that the limestones are sequentially moved. Secondary kilns are used by mixing pulverized coal with COG gas inside the primary kiln 10. In (30), only COG gas is used as fuel without using pulverized coal.

That is, in the conventional rotary kiln 205, when the pulverized coal is operated using pulverized coal 20% or more relative to the amount of gas as shown in FIG. 7, a part of the unburned pulverized coal is cooled ( By moving together with the limestone 230 and burned in the cooler 230, the quicklime product is underestimated to deteriorate its quality.

Therefore, the rotary kiln 205 using the conventional pulverized coal injection burner 220 has managed the pulverized coal injection amount to 20% or less with respect to the gas amount.

However, in the present invention, as shown in Figs. 1 and 2, the primary firing furnace 10 is provided on one side where the pulverized coal injection burner 20 is mounted, and the preheater 210 is provided at the front end of the primary firing furnace 10. ) Is located, the raw material outlet pipe 12 of the preheater 210 is connected to the front end of the primary kiln 10, the primary kiln 10 is secondary through the discharge chute 14 of the rear end Is connected to the front end of the kiln 30, the secondary kiln 30 is equipped with a COG gas burner (40).

Therefore, the preheater 210 collected at the front end of the primary firing furnace 10 preheats the raw material therein by the exhaust gas flowing from the primary firing furnace 10 to the preheater 210 side so that the raw material is the primary firing furnace ( 10) and the exhaust gas pipe 16 is connected to the dust collector 250 while being discharged from the upper side of the preheater 210 as shown in FIG.

In addition, a secondary firing furnace 30 is connected to the downstream side of the primary firing furnace 10 through a chute 14, and one side of the secondary firing furnace 30 does not emit pulverized coal to a COG gas burner 40. ) Is mounted, the cooler 230 for cooling the product is connected to the lower portion of the COG gas burner (40).

As described above, the present invention is equipped with a burner 20 using pulverized coal and COG gas as a mixed fuel in the primary firing furnace 10, and burner 40 using only COG gas as fuel in the secondary firing furnace 30. It includes the step of mounting.

In addition, the present invention is the combustion air supplied to the pulverized coal injection burner connected to the pulverized coal injection burner 20 provided on the primary firing furnace 10 side, and the pulverized coal injection burner 20 and the COG gas burners 40, combustion The air allows hot air to be provided through the conduit 232 withdrawn from the cooler 230. Therefore, the thermal efficiency of the burners 20 and 40 is improved.

The pulverized coal injection burner 20 used in the primary firing furnace 10 has a pulverized coal injection pipe 22 at the center thereof, as shown in FIGS. 3 and 4, and a plurality of combustion air engines ( 24 are formed, a COG gas pipe 26 is formed on the outside thereof, and another combustion air engine 28 is formed on the outside thereof.

The pulverized coal injection burner 20 includes a pulverized coal passing through the pulverized coal injection pipe 22 by forming a swirler 22a outside the pulverized coal injection pipe 22 to rotate combustion air, and COG The COG gas that has passed through the gas pipe 26 is mixed to burn them in the primary firing furnace 10.

As described above, the present invention does not have any problem with the content of pulverized coal used as fuel in the primary firing furnace 10, and has a feature of not limiting the amount of pulverized coal mixed with COG gas.

In the present invention, the preheater 210 and the primary firing furnace 10 are pre-heated limestone by inputting 80 to 85% of pulverized coal and COG gas relative to the total amount of fuel used, and the secondary firing furnace 30 and the cooler ( 230) includes calcining limestone with quicklime by introducing 15-20% of COG gas relative to the total amount of fuel used.

These steps are used when the pulverized coal 20% or more of the amount of the COG gas injected from the pulverized coal injection burner 20 installed in the primary firing furnace 10, as shown in Figure 2, the gas flame of the burner 20 section ( While maintaining A), the pulverized coal which is ejected at the same time is injected into the section A, part of which is burned with the gas, the other part is burned and blown into the section B, while the other part is the section C. Into the secondary firing furnace 30 through the chute 14 together with the limestone product preheated and calcined in the primary firing furnace 10 to the primary preheating and firing.

In addition, the COG gas burner 40 installed in the secondary kiln 30 has a structure in which pulverized coal is not ejected, and limestone raw material entered from the primary kiln 10 while maintaining a state in which only the COG gas and combustion air are burned. The calcined into a high quality quicklime product, and serves to cool by sending to the cooler (230).

That is, the COG gas burner 40, as shown in Fig. 5 and 6, the COG gas pipe 44 is formed on the outside of the plurality of combustion air engines 42 having the swirler 42a, Outside the combustion engine 46 is formed structure.

The COG gas burner 40 rotates the combustion air through the swirler 42a, mixes the COG gas passing through the COG gas pipe 44 with the combustion air, and mixes them with the combustion air. It is burned internally.

In this case, in the secondary kiln 30, the flame from the COG gas burner 40 additionally adds the pulverized coal introduced from the primary kiln 10 in the front side section E of the secondary kiln 30. It burns and uses the heat as calcining heat, calcined limestone over the section (D) and calcined into quicklime. In section (E), the quicklime moves and falls to the cooling stage 230 without burning. .

Through the quicklime manufacturing method of the present invention, the pulverized coal which is ejected and combusted from the pulverized coal injection burner 20 provided in the primary firing furnace 10 does not completely burn in the primary firing furnace 10, and the primary Even in the case of flowing down to the secondary kiln 30 side with the product moving in the kiln 10, the COG gas burner 40 of the secondary kiln 30 side calcined the limestone to produce a quicklime It is reburned and removed.

In addition, the heat generated in the process of reburning the pulverized coal in the secondary kiln 30 is utilized in the firing of limestone in the secondary kiln 30 to be calcined into quicklime without undermining the limestone.

As described above, the present invention includes primary and secondary firing furnaces 10 and 30, and the amount of production thereof may be adjusted according to the amount of limestone cutout stored in the preheater 210 of the primary firing furnace 10. In the related art, as shown in Table 1 of FIG. 8A, limestone is maintained for 9 to 10 hours in the preheater 210, 2.5 to 3 hours in the kiln 205, and typically 2 to 3 hours in the cooler 230. After 3 hours of stay, it is produced and discharged as quicklime.

However, in the present invention, as shown in Table 2 of FIG. 8B), the preheater 210 and the primary firing furnace 10 stay in 8.5 to 9.5 hours, and in the secondary firing furnace 30 and the cooler 230, 2.5 to 3.5 hours. In this case, the fuel injection method uses a fuel amount of 80 to 85% of the total fuel consumption of the mixed fuel of pulverized coal and COG gas in the primary kiln 10, and the COG gas in the secondary kiln 30. Use bay fuel as much as 15-20% of total fuel usage.

In addition, the present invention is a residence time of the limestone 6 to 6.5 hours in the preheater 210, 2.5 to 3 hours in the primary kiln 10, and 1 to 1.5 hours in the secondary kiln (30) In the cooler 230, it stays for 1.5 to 2 hours.

And, according to the present invention, as shown in Table 3 of Figure 8c, it is possible to adjust the production amount and quality of quicklime according to the amount of cutting or retention time of the limestone stored in the preheater 210 in front of the primary firing furnace (10). That is, when the amount of cut out of the limestone in the preheater 210 is increased, that is, when the residence time is shortened, the yield is relatively increased, but the firing time is shortened so that the degree of firing is relatively lowered.

In addition, as shown in Table 4 of FIG. 8D, the quality of the firing degree can be adjusted according to the fuel injection ratio variation of the secondary firing furnace 30. In the primary kiln 10, the fuel input amount is generally used 80 ~ 85% and 15 ~ 20% in the secondary kiln 30, but according to the quality of the quicklime product of the total input calories in the secondary kiln (30) Increasing it to 10% can improve the plasticity.

(Example)

In order to use the present invention was carried out practical operation as shown in Table 3 and Table 4 in the rotary kiln to produce 315 ~ 320 tons a day.

As shown in Table 3, when the residence time is changed by adjusting the amount of cutout in the preheater 210, that is, when the preheating time is changed, the product output is varied by ± 10% from minimum 90% to maximum 110%, respectively, The operation was carried out accordingly.

In addition, as shown in Table 4, when the fuel input amount in the secondary kiln 30 is changed from ± 90% to 90% at the minimum of 90% based on 100%, the plasticity of the product is changed from 95.5% to 98.5%.

That is, in order to manufacture high-quality quicklime, it was found that increasing the input amount of COG gas fuel in the secondary kiln 30 and changing the cutting amount of the preheater 210 can obtain the desired quality of the operator.

As described above, according to the present invention, it is possible to operate by supplying the ratio of the pulverized coal ejected from the pulverized coal injection burner 20 provided in the primary firing furnace 10 to 20% or more in comparison with gas. Since the pulverized coal can be used in a larger amount as compared with the conventional method, the pulverized coal flows in the direction of the limestone product which does not completely burn in the primary firing furnace 10 but moves inside the primary firing furnace 10 and the secondary firing furnace 30. Even if it flows in, the pulverized coal is burned by the COG gas burner 40 in the secondary kiln 30 to contribute to calcining limestone to quicklime.

As described above, the present invention not only has a problem with the content of pulverized coal injected from the primary firing furnace 10, but also saves the amount of COG gas due to not limiting the amount of pulverized coal included in the COG gas. In addition, the effect of producing high quality quicklime products is obtained by increasing the hydration rate of the fired products.

Claims (5)

In the method for manufacturing quicklime, the fine limestone supplied from the preheater 210 is blown as a heat source, fired into quicklime in the rotary kiln, and discharged through the cooler 230. Dividing the rotary kiln into a primary kiln (10) and a secondary kiln (30); Mounting a burner (20) using pulverized coal and COG gas as a mixed fuel in the primary firing furnace (10) and a burner (40) using only COG gas as a fuel in the secondary firing furnace (30); Preheating limestone by inputting 80-85% of pulverized coal and COG gas to the preheater 210 and the primary firing furnace 10; and, Calcining limestone by calcining the secondary calcining furnace (30) and the cooler (230) with a COG gas of 15-20% of the total amount of fuel used; calcined lime production method comprising a. The method of claim 1, wherein the preheater 210 to hold limestone for 6 to 6.5 hours, the primary firing furnace 10 to 2.5 to 3 hours, the secondary firing furnace 30 to 1 to 1.5 hours, the cooler At 230, quicklime manufacturing method characterized in that to stay 1.5 to 2 hours. In the limestone manufacturing apparatus which blows pulverized coal as a heat source from the limestone provided from the preheater 210, calcines it into quicklime inside the rotary kiln and discharges it through the cooler 230, A primary firing furnace (10) positioned at a rear side of the preheater (210) to receive preheated limestone; Pulverized coal injection burner 20 for pre-heating limestone by injecting the pulverized coal and COG gas of 80 ~ 85% of the total used fuel amount to provide a heat source to the primary kiln (10); A secondary kiln 30 connected to the primary kiln 10 in series via a chute 14 and receiving preheated limestone; and And a COG gas burner (40) for calcining limestone with quicklime by injecting 15-20% of COG gas relative to the total amount of fuel used to provide a heat source to the secondary kiln (30). The raw material outlet pipe 12 of the preheater 210 is connected to the front end of the primary firing furnace 10, the primary firing furnace 10 through the discharge chute 14 of the rear end Quicklime manufacturing apparatus, characterized in that connected to the front end of the primary kiln (30). The method of claim 3, wherein the pulverized coal injection air connected to the pulverized coal injection burner 20, and the combustion air supplied to the pulverized coal injection burner 20 and the COG gas burners (40), in the cooler (230) Quicklime manufacturing apparatus, characterized in that the hot air is provided through the conduit 232 is drawn.

Images