TWI803060B - A combustion furnace with the mixing device of fume - Google Patents

Abstract

The present invention provides a combustion furnace with the mixing device of fume, the mixing device of fume which is a portion of the flue gas and the combustion gas are mixed to form a mixed gas. Then the mixed gas is discharged from the mixing device of fume to the furnace, and further can maintain the temperature of the furnace, in addition to greatly suppress generation of nitrogen oxides, but also can reduce carbon dioxide emissions and fuel savings, while increasing combustion efficiency.

Description

Combustion furnace with flue gas mixing device

A combustion furnace, in particular to a combustion furnace with a flue gas mixing device.

At present, most domestic steam-electricity co-generation plants mainly use coal-fired boilers. Boilers will produce air pollutants such as sulfur oxides and nitrogen oxides. Nitrogen oxides may be related to the formation of acid rain and ground ozone. Compared with existing nitrogen oxide emission control technologies, There are low NOx burner (LNB), staged combustion, reburning, flue gas recirculation (FGR), selective catalytic reduction (SCR), and selective non-catalytic reduction Therefore, it is still a big challenge to select and combine the most favorable control technologies to achieve the greatest possible reduction in emissions under economically feasible conditions.

In general, when the combustion reaction reaches a chemical equilibrium, a variety of primary and secondary products will be produced. If the combustion aid is air, a small amount of nitrogen oxides (NOx) will be formed. The oxidation number and Temperature is related, for example: burning sulfur in air, when the temperature exceeds 1540°C, NOx will start to be produced, and the NOx will be more at higher temperatures, and the amount of NOx will also change with the proportion of excess oxygen.

There are many types of nitrogen oxides in the atmosphere. Among them, NO and NO2 have the most impact on air pollution. A very small part of NO will become NO2 in the furnace, and NO2 is very toxic. These are collectively called NOx. In view of With the rising awareness of environmental protection, in order to reduce its NOx emission value, the government has attached the NOx emission standard of its industrial boilers to it, which has led to the emergence of various emission control technologies for reducing NOx.

The formation of NOx is mainly through two ways, one is fuel nitrogen oxides, which are formed by combining nitrogen components contained in fuel with oxygen during combustion, and the other is thermal nitrogen oxides, which are formed by flames at high temperatures. It is formed by the reaction of nitrogen and oxygen in the combustion gas. Especially when the peak flame temperature is greater than 1600 ° C, thermal nitrogen oxides will be produced rapidly. Therefore, many methods of suppressing nitrogen oxides are known, that is, through its combustion method Inhibit its production, but its inhibitory effect is limited.

The main purpose of the present invention is to provide a combustion furnace with a flue gas mixing device, which uses the first flue gas pipe of the flue gas mixing device to transport the flue gas discharged from the second regenerative burner to the pipe body, and through the second The air pipe fittings transport the combustion-supporting gas to the pipe body, and mix part of the flue gas with the combustion-supporting gas to form a mixed gas. This mixed gas system is a preheated gas, so after being transported to the combustion furnace, the temperature of the combustion furnace can be further maintained. Not only greatly suppresses the formation of nitrogen oxides, but also reduces carbon dioxide emissions.

In order to achieve the above object, one embodiment of the present invention discloses a combustion furnace with a flue gas mixing device, comprising: a combustion furnace and a flue gas mixing device, the combustion furnace includes a furnace body, and the furnace body is provided with a row Gas port and an air inlet, the flue gas mixing device includes a pipe, a first flue gas pipe, a second flue gas pipe, a first air pipe and a second air pipe, the pipe respectively communicates with the The first flue gas pipe, the second flue gas pipe, the first air pipe and the second air pipe, the first flue gas pipe is connected to the exhaust port, the first air pipe is connected to the air inlet, The second flue gas pipe is connected to an exhaust device, and the second air pipe is connected to an air intake device;

Wherein, the combustion in the furnace produces a flue gas, and the flue gas is output to the first flue gas pipe through the exhaust port, and the first flue gas pipe transports the flue gas to the pipe body, and passes through the second flue gas a pipe fitting to output a portion of the flue gas to the exhaust device;

Wherein, the air intake device outputs a combustion-supporting gas to the pipe body through the second air pipe, and the combustion-supporting gas is mixed with part of the flue gas in the pipe body to form a mixed gas, which is passed through the first air pipe. Pipes are delivered to the air inlet to allow combustion to take place within the furnace body.

In a preferred embodiment, the second air pipe part further includes an injection pipe, the injection pipe is arranged at one end of the second air pipe part and is located in the pipe body, so as to deliver the combustion-supporting gas to the pipe body, and The smoke inside the suction pipe enters the first air pipe.

In a preferred embodiment, the first air pipe includes a tapering portion and a body portion, the tapering portion is connected to the pipe body and tapers toward the body portion, the distance between the end of the injection pipe and the body portion 55mm~95mm.

In a preferred embodiment, it further includes a gas conveying device, which communicates with the first flue gas pipe.

In a preferred embodiment, the flue gas mixing device is set at 10-12 times the hydraulic diameter downstream of the gas delivery device.

In a preferred embodiment, the flue gas mixing device is arranged at a hydraulic diameter more than 10 times downstream of the gas conveying device.

In the preferred embodiment, it further includes a first control valve, a second control valve and a control unit, the first control valve is connected to the first flue gas pipe, the first air pipe and the first regenerative One of the first external openings of the burner, the second control valve communicates with the first flue gas pipe, the first air intake pipe and the second external opening of the second regenerative burner, the control unit is connected with the The first control valve, the second control valve and an operation processing unit are connected in signal, and the control unit is used to control the first control valve and the second control valve to perform reversing switching.

The features and technical contents of the relevant patent applications of the present invention will be clearly presented in the following detailed description of preferred embodiments with reference to the drawings.

Please refer to the first figure and the second figure A, the first figure is a schematic diagram of the device according to one embodiment of the present invention, and the second figure A is a schematic diagram of the gas flow mixing according to one embodiment of the present invention. As shown in the figure, the combustion furnace with a flue gas mixing device of the present invention includes a combustion furnace 1 and a flue gas mixing device 2, which will be described in detail below.

Continuing from the above, the combustion furnace 1 includes a furnace body 11, and the furnace body 11 is provided with an exhaust port 101 and an air inlet 102, wherein combustion is carried out in the furnace body 11, and the combustion process will generate flue gas G1, and the flue gas G1 contains nitrogen oxides , carbon dioxide and other polluting gases, while the flue gas G1 is output through the exhaust port 101.

Refer to the first figure and the second figure A again, and refer to the third figure A and the third figure B together. The third figure A is an isometric schematic diagram of a flue gas mixing device according to an embodiment of the present invention, and the third figure B is the present invention. A schematic cross-sectional view of a flue gas mixing device according to an embodiment of the invention. As shown in the figure, the flue gas mixing device 2 includes a pipe body 21, a first flue gas pipe part 22, a second flue gas pipe part 23, a first air pipe part 24 and a second air pipe part 25, and the pipe body 21 communicates with the first flue gas respectively. The pipe fitting 22, the second flue gas pipe fitting 23, the first air pipe fitting 24 and the second air pipe fitting 25, wherein the pipe body 21 can communicate with the pipe fittings through the flange FL and bolts (not shown), and the first flue gas pipe fitting 22 is Connected to the exhaust port 101 of the furnace body 11, the second flue gas pipe 23 is connected to the exhaust device 3, the first air pipe 24 is connected to the air inlet 102 of the furnace body 11, and the second air pipe 25 is connected to the air intake device 4 .

Inheriting the above-mentioned device structure, the furnace body 11 of the combustion furnace 1 can be a box furnace, a vertical furnace, a cylindrical furnace or a large square furnace, but not limited thereto. Therefore, the furnace body 11 is heated by a burner. During this combustion process, flue gas G1 is generated in the furnace body 11, and the flue gas G1 is output to the first flue gas pipe 22 of the flue gas mixing device 2 through the exhaust port 101 of the furnace body 11. The flue gas pipe 22 reaches the inside of the pipe body 21. At this time, part of the flue gas G1 is transported to the exhaust device 3 through the second flue gas pipe 23 for exhaust gas discharge.

Continuing the above, in one embodiment, a gas delivery device 5 is further included, the gas delivery device 5 communicates with the first flue gas pipe 22, and the gas delivery device 5 is used to transport the flue gas G1 in the first flue gas pipe 22 to the pipe body 21. In one embodiment, the gas delivery device 5 can be an exhaust fan or a blower, but not limited thereto.

Continuing the above, the air intake device 4 will output the combustion-supporting gas G2, which is used to assist combustion, such as oxygen, but not limited thereto. The air intake device 4 is connected to the second air pipe 25. In one embodiment, the second air The pipe fitting 25 further includes an injection pipe 252. The injection pipe 252 is located at one end of the second air pipe fitting 25 and is located in the pipe body 21 to transmit the combustion-supporting gas G2 to the pipe body 21. The injection pipe 252 transmits the combustion-supporting gas G2 to the pipe body 21. In one embodiment, the first air pipe 24 includes a tapered portion 242 and a body portion 244. The tapered portion 242 is connected to the pipe body 21 and faces the body portion 244. The direction of the injection pipe 252 is tapered, the position of the end of the injection pipe 252 corresponds to the position of the main body 244, and the distance between the end of the injection pipe 252 and the main body 244 is 55mm~95mm, so as to enhance the flue gas G1 to be driven by the combustion-supporting gas G2 and entrained into it. The efficiency in the first air pipe fitting 24, when the flow rate of the flue gas G1 is 240 cubic meters per hour, and the flow rate of the combustion-supporting gas G2 is 220 cubic meters per hour, when the end of the injection pipe 252 and the body part 244 When the distance between them is 55mm, the proportion of cigarette smoke G1 can reach 9.7%. In a preferred embodiment, the exhaust pressure can also be adjusted, that is, the pressure of the first smoke pipe 22 to transmit the smoke G1. Under the same flow conditions Under lower conditions, the intake pressure, that is, the pressure of the transmission combustion-supporting gas G2, is 11,000 Pascals, and when the exhaust pressure is reduced to 1,850 Pascals, the proportion of cigarette gas G1 can reach 15.3%, but not limited thereto.

Continuing the above, in one embodiment, the flue gas mixing device 2 is arranged downstream of the gas delivery device 5 with a hydraulic diameter greater than 10 times, that is, the distance between the flue gas mixing device 2 and the gas delivery device 5 is greater than 10 times the hydraulic diameter, so that The ratio of the cigarette gas G1 in the injection pipe 252 can be maintained to avoid the distance between the smoke mixing device 2 and the gas delivery device 5 being too far, resulting in a decrease in the ratio of the cigarette gas G1, or the distance between the smoke mixing device 2 and the gas delivery device 5 Too close, so that the combustion-supporting gas G2 is entrained by the too strong flue gas G1 to the exhaust device 3 and discharged. In a preferred embodiment, the flue gas mixing device 2 is set at 10 to 12 times the hydraulic diameter downstream of the gas delivery device 5. But not limited to this.

Continuing the above, when the combustion-supporting gas G2 travels through the pipe body 21, the injection pipe 252 quickly transports the combustion-supporting gas G2, and entrains the flue gas G1 in the pipe body 21, so that the combustion-supporting gas G2 and the flue gas G1 in another part of the pipe body 21 are carried out. Mixing, this step is to preheat the combustion-supporting gas G2 to form a mixed gas G3, and the mixed gas G3 is transported to the air inlet 102 of the furnace body 11 through the first air pipe 24, so that the furnace body 11 burns according to the mixed gas G3 In this way, the gas produced after combustion is recovered and reused through the flue gas mixing device 2. Since the oxygen content of flue gas G1 is about 8-10%, its oxygen content is low, so the combination of nitrogen and oxygen The probability is greatly reduced, and the formation of nitrogen oxides can be suppressed.

Please refer to the second figure B and the second figure C, and also refer to the third figure A and the third figure B. The second figure B to the second figure C are the schematic diagrams of gas flow mixing according to another embodiment of the present invention. As shown in the figure, the combustion furnace 1 further includes a first regenerative burner 12 and a second regenerative burner 13, the first regenerative burner 12 has a first pair of inner openings 121 and a first outer opening 122, the first pair of The inner opening 121 and the first outer opening 122 are respectively arranged on both sides of the first regenerative burner 12, the second regenerative burner 13 has a second inner opening 131 and a second outer opening 132, the second inner opening 131 and the second external opening 132 are respectively arranged on both sides of the second regenerative burner 13, and the first inner opening 121 of the first regenerative burner 12 communicates with the air inlet 102 of the furnace body 11, and the second regenerative burner 12 The second inner opening 131 of the burner 13 communicates with the exhaust port 101 of the furnace body 11. In one embodiment, the first regenerative burner 12 and the second regenerative burner 13 include at least one fuel pipe FP for The fuel F is delivered to the furnace body 11 .

Continuing the above, as shown in the second figure B, the first regenerative burner 12 burns according to the fuel F, and outputs the flame FI to the furnace body 11 through the first pair of inner openings 121 of the first regenerative burner 12, and in a In the embodiment, the workpiece A to be heated is placed in the furnace body 11 of the combustion furnace 1, and the workpiece A placed in the furnace body 11 is processed. The inner opening 121 and the second inner opening 131 of the second regenerative burner 13 are oppositely arranged, and the workpiece A can be heated by the first inner opening 121 of the first regenerative burner 12 outputting the flame FI. During this combustion process, flue gas G1 is generated, which is inhaled through the second inner opening 131 of the second regenerative burner 13, and then output to the first flue gas pipe 22 of the flue gas mixing device 2 through the second outer opening 132 , the flue gas G1 will arrive at the pipe body 21 along the first flue gas pipe 22, and part of the flue gas G1 will be transported to the exhaust device 3 through the second flue gas pipe 23 for exhaust gas discharge.

Continuing from the above, the air intake device 4 outputs the combustion-supporting gas G2, and the combustion-supporting gas G2 is transmitted to the pipe body 21 through the injection pipe 252. When the combustion-supporting gas G2 travels through the pipe body 21, it is mixed with another part of the flue gas G1 in the pipe body 21, and the The combustion-supporting gas G2 is preheated to form a mixed gas G3, and the mixed gas G3 is transported to the first regenerative burner 12 through the first air pipe 24, so that the first regenerative burner 12 burns according to the mixed gas G3 and fuel F, by This can recycle the gas produced after combustion. Since the oxygen content of flue gas G1 is about 8-10%, its oxygen content is low, so the combination probability of nitrogen and oxygen is greatly reduced, and nitrogen oxidation can be inhibited The generation of things.

Please refer to the second figure C, the third figure A, the third figure B and the fourth figure. The fourth figure is a schematic diagram of the device of another embodiment of the present invention. As shown in the figure, further, the first smoke The first control valve C1 is set in the pipe fitting 22, and the second control valve C2 and the control unit 7 are set in the first air pipe fitting 24. The first control valve C1 is connected to the first flue gas pipe fitting 22, the first air pipe fitting 24 and the first The first external opening 122 of the regenerative burner 12, the second control valve C2 is connected to the first flue gas pipe 22, the first air pipe 24 and the second external opening 132 of the second regenerative burner 13, and the control unit 7 is respectively It is connected with the signal of the first control valve C1, the second control valve C2 and the arithmetic processing unit 6, and the control unit 7 is used to control the opening of the first control valve C1 and the second control valve C2 to adjust, wherein, the first control valve C1 and the The second control valve C2 is a reversing valve, but not limited thereto.

Continuing the above, in one embodiment, the first regenerative burner 12 and the second regenerative burner 13 can be used to switch the delivery gas through the first control valve C1 and the second control valve C2, that is, one of the burners Convert from exhaust gas to intake air and generate combustion flame FI to the furnace body 11. As shown in the second figure C, after the first regenerative burner 12 and the second regenerative burner 13 are reversed, the first regenerative burner 12 The connected first air pipe 24 is converted into the first flue gas pipe 22 , and the first flue gas pipe 22 connected to the first regenerative burner 12 is converted into the first air pipe 24 .

Continuing the above, as shown in the second figure C, the second regenerative burner 13 burns according to the fuel F, and outputs the flame FI to the furnace body 11 through the second inner opening 131 of the second regenerative burner 13, and burns During the process, flue gas G1 is generated, and after being inhaled through the first inner opening 121 of the first regenerative burner 12, the flue gas is output to the first flue gas pipe 22 of the flue gas mixing device 2 through the first outer opening 122, and the flue gas G1 will reach the pipe body 21 along the first flue gas pipe 22, and part of the flue gas G1 will be transported to the exhaust device 3 through the second flue gas pipe 23 for exhaust gas discharge.

Continuing from the above, the air intake device 4 outputs the combustion-supporting gas G2, and the combustion-supporting gas G2 is transmitted to the pipe body 21 through the injection pipe 252. When the combustion-supporting gas G2 travels through the pipe body 21, it is mixed with another part of the flue gas G1 in the pipe body 21, and the The combustion-supporting gas G2 is preheated to form a mixed gas G3, and the mixed gas G3 is transported to the second regenerative burner 13 through the first air pipe 24, so that the second regenerative burner 13 burns according to the mixed gas G3 and fuel F, by This can recover and reuse the gas produced after combustion.

Referring to the fourth figure again, as shown in the figure, the first flowmeter F1, the second flowmeter F2 and the first temperature sensor T1 are further provided, and the first flowmeter F1 is arranged on the first flue gas pipe 22 Anywhere, but not limited thereto, the first flow value of flue gas G1 can be detected. The second flow meter F2 is set anywhere on the first air pipe 24, but not limited here. It is enough to detect the second flow value of the combustion-supporting gas G2. The first temperature sensor T1 is installed anywhere on the furnace body 11 of the combustion furnace 1, but not limited thereto. It can sense the temperature of the furnace body The working temperature within 11 is sufficient, wherein the first temperature sensor T1 can be a thermocouple, but not limited thereto.

Continuing the above, the first flue gas pipe 22 can be further provided with a second temperature sensor T2 for sensing the first temperature value of the flue gas G1, and the first air pipe 24 can be further provided with a third temperature sensor T3 , used to sense the second temperature value of the combustion-supporting gas G2, and through the operation processing unit 6 and the first flow meter F1, the second flow meter F2, the first temperature sensor T1, the second temperature sensor T2 and the second temperature sensor The three temperature sensors T3 are connected with signals, and can receive and perform calculations based on the first flow value, the second flow value, the working temperature value, the first temperature value and the second temperature value, and generate calculation processing results, wherein the second The temperature sensor T2 and the third temperature sensor T3 are thermocouples, but not limited thereto.

To sum up, in the combustion furnace with flue gas mixing device of the present invention, the flue gas mixing device can further mix part of the flue gas with the combustion-supporting gas, that is, use the heat energy of the recovered flue gas to preheat the combustion-supporting gas to form Mixed gas, so as to reduce carbon dioxide emissions and inhibit the generation of nitrogen oxides. At the same time, it can save 30-40% of fuel, and recover and reuse up to 90% of waste heat, greatly improving combustion efficiency, so it can indeed achieve the goal of the present invention. Purpose.

But the above-mentioned ones are only preferred embodiments of the present invention, and should not limit the implementation scope of the present invention, that is, any simple equivalent changes and modifications made according to the scope of the patent application for the present invention and the contents of the description of the invention, All still belong to the scope covered by the patent of the present invention.

1: Burning furnace 101: Exhaust port 102: air inlet 11: furnace body 12: The first regenerative burner 121: The first pair of inner openings 122: The first external opening 13: Second regenerative burner 131: The second pair of inner openings 132: Second external opening 2: Flue gas mixing device 21: tube body 22: The first flue gas pipe 23: The second flue gas pipe 24: First air fitting 242: tapered part 244: Body Department 25:Second air pipe fitting 252: Injection pipe 3: exhaust device 4: Air intake device 5: Gas delivery device 6: Operation processing unit 7: Control unit A: Workpiece C1: first control valve C2: Second control valve F: Fuel F1: first flow meter F2: Second flow meter FI: Flame FL: Flange FP: fuel pipe fittings T1: The first temperature sensor T2: Second temperature sensor T3: The third temperature sensor G1: Smoke G2: combustion gas G3: mixed gas

The first figure: it is a device schematic diagram of an embodiment of the present invention; The second figure A: it is a schematic diagram of gas flow mixing in an embodiment of the present invention; The second figure B to the second figure C: it is a schematic diagram of gas flow mixing in another embodiment of the present invention; Figure 3 A: It is an isometric schematic diagram of a flue gas mixing device according to an embodiment of the present invention; Figure 3 B: It is a schematic cross-sectional view of a flue gas mixing device according to an embodiment of the present invention; and Figure 4: It is a schematic diagram of a device according to yet another embodiment of the present invention.

1: Burning furnace

11: furnace body

101: Exhaust port

102: air inlet

2: Flue gas mixing device

3: exhaust device

4: Air intake device

5: Gas delivery device

Claims (7)

A combustion furnace with a flue gas mixing device, comprising: a combustion furnace including a furnace body, a first regenerative burner and a second regenerative burner, the furnace body is provided with an exhaust port and an air inlet , one of the first internal openings of the first regenerative burner communicates with the air inlet, one of the second internal openings of the second regenerative burner communicates with the exhaust port; and a flue gas mixing device, comprising a Pipe body, a first flue gas pipe, a second flue gas pipe, a first air pipe and a second air pipe, the pipe respectively communicates with the first smoke pipe, the second smoke pipe, the second An air pipe and the second air pipe, the first smoke pipe communicates with the exhaust port, the first air pipe communicates with the air inlet, the second smoke pipe communicates with an exhaust device, and the first air pipe communicates with the air inlet. The two air pipes are connected to an air intake device; wherein, the combustion in the furnace produces a flue gas, which is output to the first flue gas pipe through the exhaust port, and the first flue gas pipe delivers the flue gas to the The pipe body, and part of the flue gas is output to the exhaust device through the second flue gas pipe; wherein, the air intake device outputs a combustion-supporting gas to the pipe body through the second air pipe, and the combustion-supporting gas is delivered to the pipe body through the second air pipe. The pipe body is mixed with part of the flue gas to form a mixed gas, which is transported to the air inlet through the first air pipe, so that the furnace body is combusted. According to a combustion furnace with a flue gas mixing device described in Claim 1, wherein the second air pipe part further includes an injection pipe, the injection pipe is arranged at one end of the second air pipe part and is located in the pipe body, To transmit the combustion-supporting gas to the pipe body, and suck the smoke in the pipe body into the first air pipe. According to claim 2, a combustion furnace with a flue gas mixing device, wherein the first air pipe includes a tapered portion and a body portion, and the tapered portion is connected to the pipe body and tapers toward the body portion , the distance between the end of the spray pipe and the main body is 55mm~95mm. According to claim 1, a combustion furnace with a flue gas mixing device further includes a gas delivery device, which communicates with the first flue gas pipe. According to claim 4, a combustion furnace with a flue gas mixing device, wherein, the flue gas mixing device is arranged downstream of the gas conveying device 10 to 12 times the hydraulic diameter. A combustion furnace with a flue gas mixing device according to claim 4, wherein the flue gas mixing device is arranged at a hydraulic diameter more than 10 times downstream of the gas delivery device. According to claim 1, a combustion furnace with a flue gas mixing device further comprises a first control valve, a second control valve and a control unit, the first control valve is connected to the first flue gas pipe, the The first air pipe piece and the first external opening of the first regenerative burner, the second control valve is connected to the first flue gas pipe piece, the first air intake pipe piece and the first one of the second regenerative burner The two are open to the outside, and the control unit is respectively connected with the first control valve, the second control valve and an operation processing unit for signals, and the control unit is used to control the first control valve and the second control valve to perform reversing switching.

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