KR102260259B1 - Apparatus for increasing combustion efficiency of hot blast stoves - Google Patents

Abstract

Disclosed is an apparatus for increasing the combustion efficiency of an air heating furnace. According to an embodiment of the present invention, the apparatus for increasing the combustion efficiency of an air heating furnace includes: a cold air supply pipe supplying high-temperature cold air supplied from an air blower to a heat storage chamber of an air heating furnace to convert the same into high-temperature hot air; a hot air supply pipe supplying the high-temperature hot air to a blast furnace; a mixture cold pipe connecting the cold air supply pipe with the hot air supply pipe, and supplying at least some of the cold air passing through the cold air supply pipe to the hot air supply pipe to control the temperature of the hot air supplied to the blast furnace; and a parallel cold air pipe connected in parallel with the mixture cold pipe. During the progress of a combustion process, combustion gas, in which blast furnace gas is mixed with coke gas, and combustion air are supplied to a burner of the air heating furnace for primary combustion, and then, when an oxygen concentration of exhaust gas produced during the combustion is below a set value, the cold air is supplied to the burner through the parallel cold air pipe for secondary combustion.

Description

Apparatus for increasing combustion efficiency of a hot stove {APPARATUS FOR INCREASING COMBUSTION EFFICIENCY OF HOT BLAST STOVES}

The present invention relates to a device for increasing the combustion efficiency of a hot stove.

In the combustion process of the hot stove, the combustion air, which is the sucked atmospheric air, and the combustion gas in which the blast furnace gas (BFG) and coke gas (COG) are mixed is supplied to the burner of the combustion chamber of the hot stove and burned. Stove Waste Gas generated during combustion is discharged to the chimney, and the high-temperature gas passes through the heat storage chamber of the hot stove to preheat the furnace. At this time, the amount of supplied combustion air is a value obtained by multiplying the amount of combustion gas, the theoretical air amount, and the excess air ratio. And in the case of gas combustion, the excess air ratio is 1.05 to 1.1, and if the calorie (calorific value) of ^{the combustion gas is about 900Kcal/Nm 3} , the combustion air amount is about 80% when the combustion gas amount is 100% in the hot stove facility. Thereafter, the cold air supplied from the blower (Cold Blast) passes through the heat storage chamber and becomes hot air at high temperature and is supplied to the blast furnace.

On the other hand, the temperature of the combustion air and combustion gas supplied into the combustion chamber during the combustion operation of the hot stove for generating the hot air supplied to the blast furnace has a great influence on the combustion efficiency. Therefore, a method for improving thermal efficiency by increasing the temperature of combustion air and combustion gas supplied into the combustion chamber has been proposed.

For example, in the prior Korean Patent Application Laid-Open No. 10-2003-0054318 (published on July 2, 2003), while supplying cold air higher than room temperature through a blower, a part of it is supplied to the combustion air pipe to increase the temperature of the combustion air to improve combustion efficiency. We have presented the technology to make it happen.

However, for example, when the flow rate, pressure, and temperature of the cold air supplied from the blower are 3,900Nm ³ /min, 3.1Kg/cm ² , 170℃, respectively, and the combustion gas consumption is 110KNm ³ /h, the consumption of combustion air is 120KNm ³ / h, and when converted to the same unit as the cold air flow rate, the flow rate, pressure, and temperature are ^{about 2,000 Nm 3} /min, 800 mmAq, and 50 °C, respectively. Cold air flow 3,900Nm ³ / min in consideration of the maximum 200Nm ³ / min degree of cold spare is because it can be supplied to the combustion air pipe, 100Nm ³ / min with a 170 ℃ the combustion air of the atmospheric temperature 2,000Nm ³ / min It is difficult to actually increase the combustion efficiency because the temperature rise of the combustion air is insignificant even when the cold air of In order to raise the combustion air at 50°C to 110°C, which is increased by 60°C using cold air, about 700Nm ³ /min or more is required, so it is difficult to actually apply the above-described prior art.

Korean Patent Publication No. 10-2003-0054318 (published on July 2, 2003)

In an embodiment of the present invention, combustion gas and combustion air are supplied to a burner to achieve primary combustion, and high-temperature cold air is supplied to the upper part of the burner to achieve secondary combustion, thereby improving the combustion efficiency of the hot stove combustion efficiency. would like to provide

According to one aspect of the present invention, a cold air supply pipe for supplying high-temperature cold air supplied from a blower to a heat storage chamber of a hot air furnace to be converted into high-temperature hot air; a hot air supply pipe for supplying the high temperature hot air to the blast furnace; a mixed cooling pipe connecting the cold air supply pipe and the hot air supply pipe and supplying at least a portion of the cold air passing through the cold air supply pipe to the hot air supply pipe in order to control the temperature of the hot air supplied to the blast furnace; and a parallel cold wind pipe connected in parallel with the mixed cooling pipe; but, during the combustion process, the combustion gas and the combustion air in which the blast furnace gas and coke gas are mixed are supplied to the burner of the hot stove for primary combustion, When the oxygen concentration of the exhaust gas generated during the combustion is lower than the set value, the cold air is supplied to the burner through the parallel cold air pipe to provide a device for increasing the combustion efficiency of the hot stove for secondary combustion.

A combustion gas pipe for supplying the combustion gas to the burner, a combustion air pipe for supplying the combustion air to the burner, and a combustion gas flow rate for adjusting the flow rate of the combustion gas passing through the combustion gas pipe according to a set value A regulator, a combustion air flow rate regulator that adjusts the flow rate of the combustion air passing through the combustion air pipe according to a set value, and a combustion air amount calculated according to the concentration of components constituting the combustion gas in a state excluding the excess air rate and a theoretical air-fuel ratio calculator to deliver the input value of the air-fuel ratio calculator to the air-fuel ratio calculator, and a ratio obtained by multiplying the air-fuel ratio calculated by the air-fuel ratio calculator by the performance value of the combustion gas flow rate controller as the set value of the combustion air flow rate controller. can

A cold air flow rate regulator for adjusting the flow rate of the cold air supplied to the upper part of the burner through the parallel cold air pipe based on a set value, an exhaust gas discharge pipe for discharging the exhaust gas, and the exhaust gas discharged through the exhaust gas discharge pipe An oxygen amount regulator operated when the oxygen concentration of is lower than a set value, a first operator for multiplying a set value of the excess air rate and a set value of the combustion air flow rate controller to calculate a result value, the output value of the oxygen amount controller and the It may further include a second operator for transferring a value obtained by multiplying the result calculated by the first operator as a set value of the cold air flow rate controller.

In the apparatus for increasing combustion efficiency of a hot stove according to an embodiment of the present invention, primary combustion is performed by supplying combustion gas and combustion air to a burner, and secondary combustion is achieved by supplying high-temperature cold air to the upper part of the burner to increase the combustion efficiency of the hot stove. can be improved

Effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 shows an apparatus for increasing combustion efficiency of a hot stove according to an embodiment of the present invention.
Figure 2 shows the relationship between the combustion gas calories and the internal temperature of the hot air fan.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The embodiments introduced below are provided as examples in order to sufficiently convey the spirit of the present invention to those of ordinary skill in the art to which the present invention pertains. The present invention is not limited to the embodiments described below and may be embodied in other forms. In order to clearly explain the present invention, parts irrelevant to the description are omitted from the drawings, and in the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. Like reference numerals refer to like elements throughout.

Referring to FIG. 1 , the apparatus 100 for increasing the combustion efficiency of a hot stove according to an embodiment of the present invention includes a combustion chamber 111 including a burner 101 and a shaft preheated by high-temperature gas supplied from the combustion chamber 111 . A hot stove 110 having a heat storage chamber 112 containing a hot-rolled furnace, a combustion gas pipe L11 for supplying a mixture of blast furnace gas and coke gas to the burner 101 to the combustion chamber 111, and a burner A combustion air pipe (L12) for supplying combustion air to 101, a cold air supply pipe (L13) for supplying the cold air supplied from the blower (10) to the heat storage chamber (112) to be converted into high-temperature hot air, and A hot air supply pipe (L14) for supplying hot air to the blast furnace (20), a cold air supply pipe (L13) and a hot air supply pipe (L14) are connected, and a cold air supply pipe (L13) to control the temperature of the hot air supplied to the blast furnace (20) It includes a mixed cooling pipe (L15) for supplying at least a portion of the cold air passing through to the hot air supply pipe (L14), and a parallel cold air pipe (L16) connected in parallel with the mixed cooling pipe (L15).

Here, during the combustion process, when the combustion gas and combustion air are supplied to the burner 101 to achieve primary combustion, and when the oxygen concentration of the exhaust gas generated during combustion is lower than the set value, through the parallel cold air pipe (L16) Cold air is supplied to the burner 101 to perform secondary combustion.

Through this, it is possible to maintain the internal temperature of the hot stove at the same level as in the prior art even when the combustion process is performed by reducing the amount of combustion gas compared to the prior art.

In addition, the hot stove combustion efficiency increasing device 100 includes a combustion gas flow rate regulator 120 that adjusts the flow rate of combustion gas passing through the combustion gas pipe L11 according to a set value, and the combustion air pipe L12. The input value of the combustion air flow rate controller 130 that adjusts the flow rate of the combustion air according to the set value, and the air-fuel ratio calculator 145 by calculating the amount of combustion air according to the concentration of components constituting the combustion gas in a state excluding the excess air rate A ratio that transmits the value obtained by multiplying the stoichiometric air-fuel ratio calculator 140 and the air-fuel ratio calculated by the air-fuel ratio calculator 145 and the performance value of the combustion gas flow rate controller 120 to the set value of the combustion air flow rate controller 130 . (150).

In addition, the apparatus 100 for increasing the combustion efficiency of the hot stove includes a cold air flow rate controller 160 that adjusts the flow rate of the high temperature cold air supplied to the upper part of the burner 101 through the parallel cold air pipe L16 based on the set value, and An exhaust gas discharge pipe (L17) for discharging exhaust gas generated during one combustion, and an oxygen amount regulator (170) which is operated when the oxygen concentration of the exhaust gas discharged through the exhaust gas discharge pipe (L17) is lower than the set value, and excess air The first operator 180 for multiplying the set value of the rate and the set value of the combustion air flow rate controller 130 to calculate a result value, and the output value of the oxygen amount controller 170 and the result value calculated by the first operator 180 and a second calculator 190 that transfers the multiplied value by the cold air flow rate controller 160 as a set value.

Hereinafter, the hot stove combustion process performed by the apparatus 100 for increasing the combustion efficiency of the hot stove will be described.

During the combustion process, combustion gas and combustion air are supplied to the burner 101 of the hot stove combustion chamber 111 through the combustion gas pipe L11 and the combustion air pipe L12, respectively. At this time, the BGV and BAV valves provided in the combustion gas pipe (L11) and the combustion air pipe (L12) are opened, respectively.

The flow rate of combustion gas passing through the combustion gas pipe (L11) is controlled by the combustion gas flow rate controller 120, and the flow rate of the combustion air passing through the combustion air pipe (L12) is controlled by the combustion air flow rate controller 130 do.

The combustion gas flow rate regulator 120 receives the flow rate of the combustion gas from the flow rate detector 21 provided in the combustion gas pipe L11, and controls the control valve 22 provided in the combustion gas pipe L11 based on the set value. Thus, it is possible to control the flow rate of the combustion gas passing through the combustion gas pipe (L11). The combustion gas flow rate controller 120 may be automatically operated when the flow rate of the combustion gas passing through the combustion gas pipe L11 exceeds a preset flow rate.

The combustion air flow rate controller 130 may be operated simultaneously with the automatic operation of the combustion gas flow rate controller 120 . The combustion air flow rate regulator 130 receives the flow rate of combustion air from the flow rate detector 23 provided in the combustion air pipe L12, and controls the control valve 24 provided in the combustion air pipe L12 based on the set value. Thus, it is possible to control the flow rate of the combustion air passing through the combustion air pipe (L12).

Here, the value obtained by multiplying the air-fuel ratio calculated by the air-fuel ratio calculator 145 and the performance value of the combustion gas flow rate controller 120 is input as a set value of the combustion air flow rate controller 130 .

To this end, the stoichiometric air-fuel ratio calculator 140 calculates the amount of combustion air according to the concentration of components constituting the combustion gas in a state excluding the excess air ratio, unlike the conventional one, and transmits it as an input value of the air-fuel ratio calculator 145, and the ratio unit ( 150) transmits the value obtained by multiplying the air-fuel ratio calculated by the air-fuel ratio calculator 145 and the performance value of the combustion gas flow rate controller 120 as a set value of the combustion air flow rate controller 130 . Through this process, for example, when the combustion gas calorie is 840Kcal/Nm ^{3 ,} when the combustion gas flow rate is 1, the combustion air can be supplied at a rate of about 0.75.

When the above-described combustion gas and combustion air are ignited by the burner 101, they are primarily combusted while generating high-temperature gas.

The gas of high heat is supplied to the heat storage chamber 112 to preheat the heat storage furnace, and the cold air supplied from the blower 10 through the cold air supply pipe L13 is supplied to the heat storage chamber 112 and converted into hot air of high temperature, of the hot air is supplied to the blast furnace 20 through the hot air supply pipe (L14). During the combustion process, the HBV valve of the hot air supply pipe L14 is maintained in a closed state.

At least a portion of the cold air passing through the cold air supply pipe (L13) is supplied to the hot air supply pipe (L14) through the mixed cooling pipe (L15), and the hot air is supplied to the blast furnace (20) through the hot air supply pipe (L14). temperature can be adjusted. A control valve 25 is provided in the mixed cooling pipe L15 , and the degree of opening of the corresponding control valve 25 may be adjusted by the flow rate controller 102 . During the combustion process, the CBMV valve of the mixed cooling pipe (L15) is maintained in a closed state. Since the parallel cold air pipe (L16) is provided to bypass the control valve 25 and the CBMV valve of the mixed cooling pipe (L15), the cold air flows through the parallel cold air pipe (L16) even when the mixed cooling pipe (L15) is closed. can

The exhaust gas generated during combustion by the above-described burner 101 passes through the chimney 103 through the exhaust gas discharge pipe L17 and is exhausted. For reference, when the combustion process is completed, the above-described BGV and BAV valves and the CBIMV valve of the exhaust gas discharge pipe L17 are closed.

When the oxygen concentration of the exhaust gas discharged through the exhaust gas discharge pipe (L17) is lower than the set value, the oxygen amount regulator 170 is automatically operated, and cold air is supplied to the burner 101 through the parallel cold air pipe (L16). do. The output signal (value) of the oxygen amount controller 170 is selected by the first selector SW1 and transmitted to the second operator 190 .

An exhaust gas temperature gauge T1 may be provided in the exhaust gas discharge pipe L17, and the exhaust gas temperature controller 172 is operated based on the temperature value measured by the exhaust gas temperature gauge T1. As the combustion time elapses, the temperature of the heat storage chamber 112 increases, and accordingly, the temperature of the exhaust gas temperature meter T1 increases. At this time, when the temperature rises above the first set value, it is selected from the second selector SW2 for protection of the harp (iron bearing) supporting the combustion chamber of the heat storage chamber 112, and the combustion gas flow rate controller 120 is set. It works to lower the value. Even after that, if the temperature of the exhaust gas temperature measuring device T1 rises and rises above the secondary set value, the operation of stopping the corresponding hot stove 110 is performed.

In addition, the hot stove temperature controller 174 is operated based on the temperature value of the hot stove temperature measuring device T2 for measuring the internal temperature of the hot stove 110 . The output signal of the hot stove temperature controller 174 may be selected from the first selector SW1 or the second selector SW2 and transmitted to the combustion gas flow rate controller 120 or the second operator 190 .

The cold air flow rate controller 160 receives the flow rate of the cold air passing through the parallel cold air pipe L16 from the flow rate detector 26 provided in the parallel cold air pipe L16, and is provided in the parallel cold air pipe L16 based on the set value. By controlling the control valve (27), the flow rate of the cold air passing through the parallel cold air pipe (L16) is controlled.

The set value of the cold air flow rate controller 160 is a value obtained by multiplying the output value of the oxygen amount controller 170 received from the second calculator 190 and the result value calculated by the first calculator 180 . The result value calculated by the first calculator 180 is a value obtained by multiplying the set value of the excess air rate by the set value of the combustion air flow rate controller 130 .

Since the HBV valve of the hot air supply pipe (L14) is in a closed state, cold air (approximately 160 °C) is supplied to the heat rising by combustion in the burner 101 through the parallel cold air pipe (L16) to perform secondary combustion.

Using the conventional combustion method, the internal temperature of the hot air fan 110 in the condition of using the combustion gas of ^{840Kcal/Nm 3 of the combustion gas calories rises to approximately 1245 ℃.}

On the other hand, if the embodiment of the present invention in which the above-described primary combustion and secondary combustion are applied, the internal temperature of the hot air fan 110 is approximately 1275 under the condition that combustion gas of ^{840Kcal/Nm 3 of combustion gas calories is used in the same way as in the prior art.} rise to °C. This is an increase of 30°C compared to the prior art, and it can be seen that there is an effect of increasing the combustion efficiency of the hot stove. At this time, when the actual value of the oxygen amount regulator 170 is 0.8 to 1.2%, the internal temperature of the hot air fan 110 may rise to approximately 1275°C.

Specifically, referring to FIG. 2, assuming that the excess air rate during gas combustion is 1.05, when the combustion gas calories are 840Kcal/Nm ³ , the internal temperature of the hot air fan is approximately 1245° C. and the combustion gas calories are 965 Kcal/Nm ³ When It can be seen that the internal temperature of the hot air fan is 1275 °C. That is, in order to increase the internal temperature of the hot air fan by 30°C, it is necessary to increase the combustion gas calories by 125 Kcal/Nm ³ or increase the amount of combustion gas corresponding to this.

However, through the above-described embodiment of the present invention, Secondary combustion by supplying cold air (approximately 160℃) to the burner 101 through the parallel cold wind pipe (L16) without burning by increasing the combustion gas calories by 125Kcal/Nm ^{3 or by increasing the amount of combustion gas corresponding to this} By doing so, it is possible to increase the combustion efficiency of the hot stove.

As described above, when the apparatus 100 for increasing the combustion efficiency of the hot stove according to the present invention as shown in FIG. 1 is applied under the conditions of using the combustion gas of the amount of heat (840 Kcal/Nm ^{3 ) in the same manner as in the prior art, the internal temperature of the hot stove dome} is increased by 30 °C compared to the prior art. This is the same effect as when the amount of heat of combustion gas ^{is increased by 125 (Kcal/Nm 3} ), and when converted into the flow rate of combustion gas, it is as follows.

That is, since the combustion gas is ^{a mixed gas of BFG (766 Kcal/Nm 3} ) and COG (4250 Kcal/Nm ³ ), in order to increase the amount of heat in the same state, COG having a high calorific value must be increased.

Conventional combustion gas calorific value 840(Kcal/Nm ³ ) is the sum of BFG calorific value (766 Kcal/Nm ³ ) and COG calorific value (4250 Kcal/Nm ³ ), 766*(1-0.023)+4250*(0.023)=840 (Kcal/Nm ³ ).

When the above-described embodiment of the present invention is applied, the amount of heat is increased to 840(Kcal/Nm ³ )+125(Kcal/Nm ³ )= 965(Kcal/Nm ³ ), which is 766*(1-0.056)+4250* (0.056) = 960 (Kcal/Nm ³ ).

Conventionally, when the amount of heat is 840 (Kcal/Nm ³ ) at the flue gas flow rate of 110,000 (Nm ³ /h), BFG is 107,470 (Nm ³ /h), COG is 2,530 (Nm ³ /h), and the amount of heat is 965 (Kcal/h) At Nm ³ ), BGF is 103,840 (Nm ³ /h) and COG is 6,160 (Nm ³ /h), indicating that expensive COG is 3,630 (Nm ³ /h) more. It can be seen that through the embodiment of the present invention, the effect of using a large amount of heat can be obtained even when the ^{amount of COG used is 3,630 (Nm 3 /h) less.} The price of BFG 1 (Nm ³ /h) is about 29.9 won, and the price of COG 1 (Nm ³ /h) is about 175.8 won, which is 6 times difference. It can save billions of dollars in cost.

In the above, specific embodiments have been shown and described. However, the present invention is not limited to the above embodiments, and those of ordinary skill in the art to which the invention pertains can make various changes without departing from the spirit of the invention described in the claims below. will be able

101: burner 110: hot stove
111: combustion chamber 112: heat storage chamber
120: combustion gas flow regulator 130: combustion air flow regulator
140: theoretical air-fuel ratio calculator 145: air-fuel ratio calculator
150: ratio unit 160: cold air flow rate controller
170: oxygen amount regulator 180: first operator
190: second operator L11: combustion gas pipe
L12: Combustion air pipe L13: Cool air supply pipe
L14: hot air supply pipe L15: mixed cooling pipe
L16: Parallel cold air pipe L17: Exhaust gas discharge pipe

Claims (3)

a cold air supply pipe for supplying high-temperature cold air supplied from the blower to the heat storage chamber of the hot air furnace to be converted into high-temperature hot air;
a hot air supply pipe for supplying the high temperature hot air to the blast furnace;
a mixed cooling pipe connecting the cold air supply pipe and the hot air supply pipe and supplying at least a portion of the cold air passing through the cold air supply pipe to the hot air supply pipe in order to control the temperature of the hot air supplied to the blast furnace; and
A parallel cold wind pipe connected in parallel with the mixed cooling pipe; including,
During the combustion process, combustion gas and combustion air in which the blast furnace gas and coke gas are mixed are supplied to the burner of the hot stove to perform primary combustion,
When the oxygen concentration of the exhaust gas generated during the combustion is lower than the set value, the cold air is supplied to the burner through the parallel cold air pipe to achieve secondary combustion. According to claim 1,
a combustion gas pipe for supplying the combustion gas to the burner;
a combustion air pipe for supplying the combustion air to the burner;
A combustion gas flow rate regulator for adjusting the flow rate of the combustion gas passing through the combustion gas pipe according to a set value;
a combustion air flow rate regulator for adjusting the flow rate of the combustion air passing through the combustion air pipe according to a set value;
A stoichiometric air-fuel ratio calculator that calculates the amount of combustion air according to the concentration of components constituting the combustion gas in a state excluding the excess air ratio and transmits it as an input value of the air-fuel ratio calculator;
The apparatus for increasing the combustion efficiency of a hot stove further comprising a ratio unit for transferring a value obtained by multiplying the air-fuel ratio calculated by the air-fuel ratio calculator by the performance value of the combustion gas flow rate controller as a set value of the combustion air flow rate controller. 3. The method of claim 2,
a cold air flow rate controller for adjusting the flow rate of the cold air supplied to the upper part of the burner through the parallel cold air pipe based on a set value;
an exhaust gas discharge pipe for discharging the exhaust gas;
an oxygen amount regulator operated when the oxygen concentration of the exhaust gas discharged through the exhaust gas discharge pipe is lower than a set value;
A first calculator for calculating a result value by multiplying the set value of the excess air rate and the set value of the combustion air flow rate controller;
The apparatus for increasing the combustion efficiency of a hot stove further comprising a second calculator for transferring a value obtained by multiplying the output value of the oxygen amount controller and a result value calculated by the first calculator as a set value of the cold air flow controller.

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