burner

Abstract

To provide a burner that can discharge combustion exhaust gas containing high-concentration carbon dioxide suitable for recovery of carbon dioxide by using a carbon dioxide separation device such as a PSA device, can suppress a combustion temperature and enables stable combustion.SOLUTION: A burner includes: a first pipe part for supplying first gas that is one of fuel gas and oxygen to a burner flame; a second pipe part surrounding the first pipe part and supplying second gas that is the other of the fuel gas and the oxygen to the burner flame; and a combustion exhaust gas supply part that supplies combustion exhaust gas containing carbon dioxide from a radial outer side of the second pipe part to the burner flame.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a burner. [Background technology]

[0002] 2. Description of the Related Art A burner is known that burns a mixed gas, which is a mixture of combustion exhaust gas containing carbon dioxide and oxygen, and a fuel gas (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 55-162414 Summary of the Invention [Problem to be solved by the invention]

[0004] It is preferable that a burner used in a furnace or the like can discharge a combustion exhaust gas containing a high concentration of carbon dioxide suitable for carbon dioxide capture by a carbon dioxide separation device such as a PSA (pressure swing adsorption) device. For this purpose, it is conceivable to increase the carbon dioxide concentration in the combustion exhaust gas discharged by combustion by using pure oxygen instead of air as a combustion supporting gas, but this may cause an excessive increase in combustion temperature and a problem of overheating in the burner and its surroundings. On the other hand, it is conceivable to suppress the combustion temperature while increasing the carbon dioxide concentration in the combustion exhaust gas discharged by combustion by using the combustion exhaust gas for combustion, but when using a mixed gas in which the combustion exhaust gas and oxygen are mixed in advance as described in Patent Document 1, there is a problem that the burner combustion is difficult to stabilize due to the flame quenching effect of carbon dioxide.

[0005] Therefore, an object of the present invention is to provide a burner that can discharge combustion exhaust gas containing a high concentration of carbon dioxide suitable for carbon dioxide recovery by a carbon dioxide separation device such as a PSA device, and can suppress the combustion temperature and perform stable combustion. [Means for solving the problem]

[0006] One aspect of the present invention is as follows.

[0007] [1] a first pipe portion that supplies a first gas, which is one of a fuel gas and oxygen, to a burner flame; a second pipe portion surrounding the first pipe portion and supplying a second gas, which is the other of the fuel gas and the oxygen, to the burner flame; a combustion exhaust gas supply section that supplies combustion exhaust gas containing carbon dioxide to the burner flame from a radially outer side than the second tube section.

[0008] [2] The burner according to [1], wherein the combustion exhaust gas supply section is formed by a third tubular section that surrounds the second tubular section and supplies the combustion exhaust gas to the burner flame.

[0009] [3] A burner body having the first tube portion and the second tube portion; A burner block attached to the burner body, The burner according to [1], wherein the combustion exhaust gas supply section is formed by the burner block.

[0010] [4] The burner block has a combustion exhaust gas supply port of the combustion exhaust gas supply section adjacent to the second pipe section in the radial direction of the second pipe section.

[0011] [5] The burner according to any one of [1] to [4], further comprising a mixing chamber for mixing the first gas and the second gas, located on a tip side of a tip of the first pipe portion.

[0012] [6] The first pipe section supplies the fuel gas as the first gas at a flow velocity of 12 m / s or more and 80 m / s or less, The second pipe section supplies the oxygen as the second gas at a flow velocity of 5 m / s or more and 30 m / s or less, The burner according to any one of [1] to [5], wherein the combustion exhaust gas supplying section supplies the combustion exhaust gas at a flow velocity of 10 m / s or less.

[0013] [7] The burner according to any one of [1] to [6], wherein the purity of the oxygen supplied from the second tube portion is 90% or more.

[0014] [8] A burner according to any one of [1] to [7], A carbon dioxide separator that separates the carbon dioxide; a recovery path for supplying the combustion exhaust gas from a furnace using the burner to the carbon dioxide separation device; a combustion exhaust gas supply path that supplies the combustion exhaust gas before it is supplied from the recovery path to the carbon dioxide separation device to the combustion exhaust gas supply section of the burner. Effect of the Invention

[0015] According to the present invention, it is possible to provide a burner that can discharge combustion exhaust gas containing a high concentration of carbon dioxide suitable for carbon dioxide capture by a carbon dioxide separation device such as a PSA device, and can suppress the combustion temperature and perform stable combustion. [Brief description of the drawings]

[0016] [Figure 1] FIG. 4 is a graph showing the relationship between oxygen concentration and flame temperature. [Diagram 2] FIG. 1 is a schematic diagram showing a carbon dioxide capture system according to one embodiment of the present invention. [Diagram 3] 1 is a cross-sectional view showing a burner according to a first embodiment of the present invention. [Figure 4] FIG. 4 is a front view of the burner shown in FIG. [Diagram 5] FIG. 4 is a cross-sectional view showing a burner according to a second embodiment of the present invention. [Figure 6](a) is a front view of the burner shown in FIG. 5, (b) is a first modified example of (a), (c) is a second modified example of (a), (d) is a third modified example of (a), (e) is a fourth modified example of (a), and (f) is a fifth modified example of (a). [Figure 7] FIG. 4 is a cross-sectional view showing a burner of a comparative example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0018] As shown in Figures 3 and 4, in the first embodiment of the present invention, the burner 1 has a first tubular section 3 that supplies a first gas, which is one of fuel gas and oxygen, to a burner flame 2, a second tubular section 4 that surrounds the first tubular section 3 and supplies a second gas, which is the other of fuel gas and oxygen, to the burner flame 2, and a combustion exhaust gas supply section 5 that supplies combustion exhaust gas containing carbon dioxide to the burner flame 2 from the radially outer side of the second tubular section 4.

[0019] According to the above configuration, by using the combustion exhaust gas for combustion, it is possible to suppress the combustion temperature while increasing the carbon dioxide concentration in the combustion exhaust gas discharged by combustion. Also, since the combustion exhaust gas can be supplied from the combustion exhaust gas supply unit 5 to the burner flame 2 from the radially outer side of the second pipe section 4, it is possible to maintain stable combustion of the fuel gas and oxygen from the first pipe section 3 and the second pipe section 4 radially inner side of the combustion exhaust gas supply unit 5. Therefore, it is possible to realize a burner 1 that can discharge combustion exhaust gas containing a high concentration of carbon dioxide suitable for carbon dioxide capture by a carbon dioxide separation device 6 such as a PSA device, and can suppress the combustion temperature and perform stable combustion.

[0020] The combustion exhaust gas supply section 5 is formed by the third pipe section 7 that surrounds the second pipe section 4 and supplies the combustion exhaust gas containing carbon dioxide to the burner flame 2. According to the above configuration, the combustion exhaust gas supply section 5 can be formed by the third pipe section 7. Furthermore, since the combustion exhaust gas can be supplied to the burner flame 2 from all around, even more stable combustion can be achieved.

[0021] The first pipe section 3 has a first inlet 3a, the second pipe section 4 has a second inlet 4a, the third pipe section 7 has a third inlet 7a, the inner surface of the first pipe section 3 forms a first supply passage 8, the outer surface of the first pipe section 3 and the inner surface of the second pipe section 4 form a second supply passage 9, and the outer surface of the second pipe section 4 and the inner surface of the third pipe section 7 form a third supply passage 10 as an exhaust gas supply passage for the combustion exhaust gas supply section 5, the first supply passage 8 introduces a first gas from the first inlet 3a and discharges it from the tip 3b of the first pipe section 3, the second supply passage 9 introduces a second gas from the second inlet 4a and discharges it from the tip 4b of the second pipe section 4, and the third supply passage 10 introduces the combustion exhaust gas from the third inlet 7a and discharges it from the tip 7b of the third pipe section 7. According to the above-mentioned configuration, it is possible to increase the carbon dioxide concentration in the combustion exhaust gas, suppress the combustion temperature, and improve the effects of stabilizing the combustion.

[0022] The burner has a burner body 11 having a first tube portion 3, a second tube portion 4, and a third tube portion 7, and a burner block 12 attached to the burner body 11, and the burner block 12 has a through hole 12a into which the burner body 11 is inserted. According to the above configuration, the burner body 11 can be fixed to the wall of a facility such as a furnace 13 (see FIG. 2) via the burner block 12. The tip of the burner body 11 may be arranged in a state of being axially recessed inside the through hole 12a of the burner block 12 as shown in FIG. 3, but is not limited to this. The material of the burner block 12 is not particularly limited, but it is preferable to form it from a fire-resistant material that can withstand the components and temperature of the burner flame 2 and the environmental atmosphere (such as the atmosphere inside the furnace), and for example, it can be formed from a castable of high-concentration alumina (for example, aluminum oxide 95% or more). In addition, the burner block 12 has a rectangular parallelepiped shape as shown in FIG. 3 to FIG. 4.

[0023] 5 to 6(a), the burner 1 may have a burner body 11 having a first pipe portion 3 and a second pipe portion 4, and a burner block 12 attached to the burner body 11, and the combustion exhaust gas supply portion 5 may be formed by the burner block 12. According to the above configuration, the combustion exhaust gas supply portion 5 can be formed by the burner block 12.

[0024] In the second embodiment, the burner block 12 may have a combustion exhaust gas supply port 12b of the combustion exhaust gas supply section 5 adjacent to the second pipe section 4 in the radial direction of the second pipe section 4. According to the above configuration, by appropriately setting the number and arrangement of the combustion exhaust gas supply ports 12b provided in the burner block 12, a good combustion exhaust gas supply section 5 can be formed.

[0025] The burner block 12 has a plurality of combustion exhaust gas supply ports 12b arranged in the circumferential direction of the second pipe section 4. According to the above configuration, by appropriately setting the number and arrangement of the combustion exhaust gas supply ports 12b arranged in the circumferential direction, a good combustion exhaust gas supply section 5 can be easily formed. The number and arrangement of such combustion exhaust gas supply ports 12b are not particularly limited, and may be configured as shown in Figs. 6(b) to 6(f), for example.

[0026] In the second embodiment, the burner block 12 has a supply hole 12c having a combustion exhaust gas supply port 12b at its tip, the burner body 11 has a surrounding portion 14 surrounding the second pipe portion 4, the first pipe portion 3 has a first inlet 3a, the second pipe portion 4 has a second inlet 4a, the surrounding portion 14 has a surrounding portion inlet 14a and a connection port 14b connected to the base end of the supply hole 12c, the inner peripheral surface of the first pipe portion 3 forms a first supply passage 8, and the outer peripheral surface of the first pipe portion 3 and the inner peripheral surface of the second pipe portion 4 form a second supply passage. The first supply passage 8 introduces the first gas from the first inlet 3a and discharges it from the tip 3b of the first pipe 3, the second supply passage 9 introduces the second gas from the second inlet 4a and discharges it from the tip 4b of the second pipe 4, and the third supply passage 10 introduces the combustion exhaust gas from the surrounding inlet 14a and discharges it from the combustion exhaust gas supply port 12b. With the above configuration, it is possible to increase the carbon dioxide concentration in the combustion exhaust gas, suppress the combustion temperature, and improve the effects of stabilizing combustion.

[0027] In the first and second embodiments, the burner 1 has a mixing chamber 15 for mixing the first gas and the second gas on the tip side of the tip 3b of the first tube section 3. According to the above configuration, the mixing chamber 15 can realize more stable combustion. In the first embodiment, the mixing chamber 15 is formed between the tip 4b of the second tube section 4 and the tip 3b of the first tube section 3 that is recessed from the tip 4b of the second tube section 4. In the second embodiment, the mixing chamber 15 is formed inside the through hole 12a of the burner block 12 into which the second tube section 4 is inserted, between the tip surface 12d of the burner block 12 and the tip 3b of the first tube section 3 and the tip 4b of the second tube section 4 that are recessed from the tip surface 12d and arranged flush with each other.

[0028] In the first and second embodiments, the flow velocities of the first gas, second gas, and combustion exhaust gas are not particularly limited, but it is preferable that the first pipe section 3 supplies fuel gas as the first gas at a flow velocity of 12 m / s or more and 80 m / s or less, the second pipe section 4 supplies oxygen as the second gas at a flow velocity of 5 m / s or more and 30 m / s or less, and the combustion exhaust gas supply section 5 supplies the combustion exhaust gas at a flow velocity of 10 m / s or less.

[0029] The purity of the oxygen supplied from the second tube section 4 is not particularly limited, but is preferably 90% or more, and more preferably 93% or more.

[0030] 2, in one embodiment of the present invention, a carbon dioxide capture system 16 includes a burner 1 according to the first or second embodiment or a modified example thereof, a carbon dioxide separation device 6 such as a PSA device that separates carbon dioxide, a recovery path 17 that supplies combustion exhaust gas from a furnace 13 that uses the burner 1 to the carbon dioxide separation device 6, and a combustion exhaust gas supply path 18 that supplies the combustion exhaust gas before being supplied from the recovery path 17 to the carbon dioxide separation device 6 to the combustion exhaust gas supply section 5 of the burner 1. According to the above configuration, it is possible to realize a carbon dioxide capture system 16 having a burner 1 that can discharge combustion exhaust gas containing a high concentration of carbon dioxide suitable for carbon dioxide capture by a carbon dioxide separation device 6 such as a PSA device, and that can suppress the combustion temperature and perform stable combustion.

[0031] The recovery path 17 has a cooler 17a for cooling the combustion exhaust gas, a filter 17b for removing dust from the combustion exhaust gas, a denitrifier 17c for removing nitrides and oxides from the combustion exhaust gas, and a dehumidifier 17d for removing water from the combustion exhaust gas. With the above configuration, a higher quality combustion exhaust gas can be supplied to the carbon dioxide separation device 6. The combustion exhaust gas supply path 18 has a blower as an air supply device 18a, but is not limited thereto.

[0032] The recovery path 17 includes, in this order from upstream to downstream, a cooler 17a, a filter 17b, a denitrifier 17c, and a dehumidifier 17d. According to the above configuration, it is possible to supply the combustion exhaust gas to the carbon dioxide separation device 6 with higher quality.

[0033] The combustion exhaust gas supply path 18 supplies the combustion exhaust gas from between the cooler 17a and the filter 17b in the recovery path 17 and the carbon dioxide separator 6 to the combustion exhaust gas supply unit 5 of the burner 1. According to the above configuration, it is possible to supply higher quality combustion exhaust gas to the combustion exhaust gas supply unit 5 of the burner 1.

[0034] 2, the combustion exhaust gas supply path 18 supplies the combustion exhaust gas from between the cooler 17a, the filter 17b, the denitrifier 17c, and the dehumidifier 17d in the recovery path 17 and the carbon dioxide separator 6 to the combustion exhaust gas supplying section 5 of the burner 1. According to the above configuration, it is possible to supply higher quality combustion exhaust gas to the combustion exhaust gas supplying section 5 of the burner 1.

[0035] The combustion exhaust gas supply path 18 may be configured to supply the combustion exhaust gas to the combustion exhaust gas supply section 5 of the burner 1 from between the cooler 17a and the filter 17b in the recovery path 17 and the denitrifier 17c and the dehumidifier 17d, as shown by the dashed line in Figure 2.

[0036] The carbon dioxide capture system 16 of this embodiment will be described in more detail below, but the carbon dioxide capture system 16 of this embodiment is not limited to this.

[0037] Industrial furnaces, which mainly burn fossil fuels as a heat source to heat, melt, and dissolve products in the steel, non-ferrous, ceramic, cement, and other manufacturing industries, emit more than 200 million tons of carbon dioxide per year in Japan, equivalent to approximately 18% of total greenhouse gas emissions. To achieve carbon neutrality by 2050, industrial furnaces are required to reduce carbon dioxide emissions to zero by using electric heating with green electricity and burning carbon-free fuels such as blue or green hydrogen and ammonia. However, for industrial furnaces that require the use of fossil fuels such as natural gas, the carbon dioxide generated must be captured and reused as a raw material, or stored underground.

[0038] Carbon dioxide capture methods include, for example, chemical absorption using amine absorbing liquids, which are large-scale facilities, and solid adsorption using solid absorbents, and are used to capture carbon dioxide from large-flow flue gas from thermal power plants and other sources. However, most industrial furnaces are small in size and are scattered in large numbers, so it is expected that the above capture methods are not suitable for capturing carbon dioxide from flue gas in small and medium-sized industrial furnaces in many cases. PSA devices using the physical adsorption method are expected to be used in society as a low-cost capture method for small and medium-sized industrial furnaces, and their device characteristics make them suitable for capturing carbon dioxide from flue gas from small-scale industrial furnaces. PSA devices have the characteristic that the higher the carbon dioxide concentration in the flue gas, the higher the carbon dioxide capture rate, and the device size and device price per kg of carbon dioxide captured can be reduced.

[0039] The combustion exhaust gas from an oxygen combustion burner, which burns fuel with pure oxygen, contains no nitrogen derived from the air used for combustion (hereafter referred to as combustion air), and therefore has a high concentration of carbon dioxide. More specifically, the combustion exhaust gas after dehumidification is composed of the excess oxygen used for combustion in the burner, trace amounts of nitrogen derived from the air drawn into the furnace from the outside, and carbon dioxide, and has a high concentration of carbon dioxide of 80-90% or more. In addition, the flow rate of the combustion exhaust gas from an oxygen combustion burner is significantly reduced to about 25-30% compared to the combustion exhaust gas from an air combustion burner, which burns air as a supporting gas, and the sensible heat carried away by the combustion exhaust gas from the furnace can be significantly reduced. As a result, the heat input into the furnace can be reduced, and fuel consumption can be significantly reduced (energy saving).

[0040] However, compared to the flame of an air-fuel burner, the flame of an oxygen-fuel burner is very hot (see Figure 1), and there is a risk of localized overheating inside the furnace. Therefore, in industrial furnaces with relatively low furnace temperatures of 1400°C or less, oxygen-enriched combustion, in which oxygen is added to the combustion air to increase the oxygen concentration in the combustion-supporting gas to 25-40%, is often used instead of oxygen combustion. The flame temperature in oxygen-enriched combustion decreases as the oxygen concentration in the combustion-supporting gas approaches 21%, the same as air, and approaches the flame temperature in air combustion. Oxygen-enriched combustion can reduce fuel consumption (energy saving) according to the reduction in the flow rate of the combustion exhaust gas. However, when oxygen-enriched combustion is performed, a large amount of nitrogen derived from the combustion air is present in the combustion exhaust gas, so the carbon dioxide concentration decreases (14-24% after dehumidification), and there was a problem in carbon dioxide capture using the above-mentioned PSA device, which has a lower carbon dioxide capture rate compared to the case of oxygen combustion, and the size and price of the device per kg of carbon dioxide captured increases.

[0041] The above-mentioned problems of overheating and recovery rate can be solved by using a burner that uses combustion exhaust gas containing high concentration of carbon dioxide instead of the combustion air used in an oxygen-enriched combustion burner that uses combustion air and oxygen as the supporting gas. However, when using a mixed gas in which combustion exhaust gas and oxygen are mixed in advance as described in Patent Document 1, the combustion speed drops significantly when the oxygen concentration in the mixed gas becomes low compared to oxygen-enriched combustion in which fuel gas is burned with a supporting gas containing oxygen and nitrogen (Reference: Safety Engineering Handbook, compiled by the Japan Society of Safety Engineering, Corona Publishing Co., Ltd., first edition published on September 30, 1973, page 241, Figures 3-89 and 3-90). In particular, when the temperature of this mixed gas is low near room temperature and the oxygen concentration falls below 40%, there is a problem that the burner combustion flame becomes unstable and blows out. If the mixed gas is heated to 900°C or higher through a heat exchanger, the flame does not easily blow out, but at lower temperatures, especially at room temperature, the above-mentioned problem occurs. The carbon dioxide capture system 16 of the present embodiment uses combustion exhaust gas containing carbon dioxide and oxygen as combustion supporting gases, and can stably combust fuel gas even at low temperatures near room temperature.

[0042] The carbon dioxide capture system 16 of this embodiment can stably and completely burn fuel using the combustion exhaust gas containing carbon dioxide and oxygen as a combustion supporting gas, while facilitating the capture by the PSA device by increasing the carbon dioxide concentration in the combustion exhaust gas generated by burning fossil fuel to 80% or more (after removing moisture), and provides heating performance equivalent to that of a conventional oxygen-enriched combustion burner that burns fuel with a combustion supporting gas containing oxygen and nitrogen. The carbon dioxide capture system 16 of this embodiment is used in industrial furnaces for heating, melting, and dissolving products in the manufacturing industries of steel, non-ferrous metals, ceramics, cement, etc., and captures carbon dioxide. The captured carbon dioxide is used or stored. The combustion exhaust gas discharged from the industrial furnace is cooled, and impurities such as dust and nitrogen oxides and moisture are removed, and then a part of it is blown by a blower and supplied to the burner 1 (see FIG. 2). In this exhaust gas treatment, removal is performed according to the purity required for the raw material gas by the PSA device in the subsequent stage and the required cleanliness inside the industrial furnace. Depending on the quality requirements of the product to be heated in the industrial furnace, the combustion exhaust gas discharged from the industrial furnace may be cooled, dust removed, and then sent by a blower before removing nitrogen oxides and moisture, and supplied to the burner 1. In that case, the combustion exhaust gas containing carbon dioxide will have a temperature of 300°C or less, and if it is sent to the burner 1 while maintaining a temperature of 100°C or more, it will contain a high concentration of water vapor (up to 64%) generated by the combustion of the fuel gas.

[0043] A preferred embodiment of the carbon dioxide capture system 16 of the present embodiment described above will be described in more detail. The fuel gas may be city gas (13A), natural gas, LPG (liquefied petroleum gas), other gaseous fossil fuels, carbon monoxide, etc. In the carbon dioxide capture system 16 of the present embodiment, the downstream side refers to the region inside the furnace where the burner flame 2 is formed by combustion, and the upstream side refers to the opposite side to the downstream side.

[0044] In the carbon dioxide recovery system 16 of this embodiment, the combustion exhaust gas is a combustion exhaust gas discharged from an industrial furnace, and has a total concentration of carbon dioxide and water vapor of 80% or more. Preferably, the carbon dioxide concentration of the combustion exhaust gas containing carbon dioxide is 80% or more when converted into a dry gas (converted value when dehumidified). Furthermore, the combustion exhaust gas contains nitrogen and oxygen as secondary components in addition to carbon dioxide and water vapor. However, the gas components of the secondary components are not particularly limited.

[0045] The flow rate of the fuel gas and oxygen is expressed as the ratio of the actual oxygen amount to the theoretical oxygen amount for combustion as the oxygen ratio m (m = actual oxygen supply amount / theoretical oxygen amount for combustion), and the fuel gas and oxygen are supplied to the burner 1 so that the value of m (m value) is in the range of 1.05 to 1.1. By setting the m value to 1.05 or more, the fuel can be completely burned. By setting the m value to 1.1 or less, unnecessary oxygen that is not involved in the combustion reaction can be eliminated, and the carbon dioxide concentration of the combustion exhaust gas can be increased. Even if the m value is 1.1 or more, it does not adversely affect the stability of the burner flame 2. The m value is preferably set to 1.05, and the carbon dioxide concentration in the combustion exhaust gas after dehumidification can be increased. The fuel gas is ejected from the fuel gas supply pipe (first pipe section 3) located in the center toward the downstream at a flow velocity of 12 m / s to 80 m / s. By setting the fuel gas flow velocity to 12 m / s or more, complete combustion can be achieved without a large amount of unburned matter such as soot adhering to the end of the fuel gas supply pipe. By setting the flow velocity of the fuel gas to 80 m / s or less, the fuel gas can be burned stably. Oxygen is ejected downstream from the oxygen supply pipe on the radially outer side at a flow velocity of 5 m / s or more and 30 m / s or less. By setting the flow velocity of the oxygen to 5 m / s or more, a pilot flame is formed at the end of the fuel gas supply pipe, and a stable burner flame 2 can be obtained. By setting the flow velocity of the oxygen to 30 m / s or less, a similarly stable burner flame 2 can be obtained. The oxygen concentration of the oxygen ejected from the oxygen supply pipe is 90% or more, and preferably 93% or more. By setting the oxygen concentration to 93% or more, the fuel gas can be burned stably and the carbon dioxide in the combustion exhaust gas can be highly concentrated.

[0046] The combustion exhaust gas is supplied to the burner 1 at a flow rate such that the ratio of the oxygen flow rate to the total gas flow rate (combustion exhaust gas and oxygen flow rate) excluding the fuel gas ejected downstream from the burner 1 is 0.1 to 1.0, and is ejected downstream from the carbon dioxide supply section (combustion exhaust gas supply section 5) at a flow velocity of 10 m / s or less. As a result, the fuel gas can be burned stably.

[0047] Since the burner 1 is composed of separate fuel gas supply pipes, oxygen supply pipes, and carbon dioxide supply units, the fuel gas, oxygen, and combustion exhaust gas containing carbon dioxide are supplied independently to the burner 1. As a result, a stable pilot flame is formed by the fuel gas and oxygen. This makes it possible to maintain a stable burner flame 2 even if carbon dioxide, which has a flame-extinguishing effect, is supplied to the burner 1.

[0048] In the carbon dioxide capture system 16 of this embodiment, when the burner 1 of the first embodiment or the various modified examples described above is included, the downstream end of the fuel gas supply pipe is disposed upstream of the downstream end of the oxygen supply pipe, thereby forming a fuel and oxygen mixing chamber 15 without carbon dioxide. In this case, the distance L1 (see FIG. 3) between the downstream end of the oxygen supply pipe and the downstream end of the fuel gas supply pipe is 1 to 3 times the inner diameter D1 of the oxygen supply pipe. As a result, the pilot flame of the burner flame 2 formed from the end of the fuel gas supply pipe toward the downstream is stabilized, and the influence of the flame quenching action of carbon dioxide supplied from the outside can be suppressed.

[0049] In the carbon dioxide capture system 16 of this embodiment, when the burner 1 of the second embodiment or the various modified examples (including the first to fifth modified examples) described above is included, the burner block 12 has a combustion exhaust gas supply port 12b (see FIG. 5 and FIG. 6(a) to (f)). In addition, by arranging the downstream end of the fuel gas supply pipe and the downstream end of the oxygen supply pipe upstream of the tip face 12d of the burner block 12 where the combustion exhaust gas supply port 12b is located, a mixing chamber 15 of fuel and oxygen without carbon dioxide is formed. At this time, the distance L2 (see FIG. 5) between the tip face 12d of the burner block 12 and the downstream end of the fuel gas supply pipe and the downstream end of the oxygen supply pipe is 1 to 10 times the inner diameter D2 of the tip of the through hole 12a of the burner block 12. As a result, the pilot flame of the burner flame 2 formed from the end of the fuel gas supply pipe toward the downstream is stabilized, and the influence of the flame quenching action of carbon dioxide supplied from the outside can be suppressed.

[0050] By providing the combustion exhaust gas supply port 12b in the burner block 12, the distance between the combustion exhaust gas containing carbon dioxide and the burner flame 2 becomes short, so that the combustion exhaust gas and the combustion gas in the burner flame 2 can be mixed uniformly. As a result, unevenness in temperature distribution and gas composition is less likely to occur in the industrial furnace. If the radius of the inner peripheral surface of the oxygen supply pipe (second pipe section 4) shown in FIG. 6(a) is R1 and the distance from the center of the second pipe section 4 to the center of the combustion exhaust gas supply port 12b is R2, R2 / R1 is preferably 2 to 10, more preferably 2 to 7. By setting R2 / R1 in this range, the combustion exhaust gas and the combustion gas can be mixed more uniformly. As shown in FIG. 6(a) to (f), the burner block 12 preferably has a plurality of combustion exhaust gas supply ports 12b arranged at equal angles on a concentric circle in the circumferential direction of the second pipe section 4, and this configuration makes it easier to mix the combustion exhaust gas and the combustion gas more uniformly.

[0051] In the carbon dioxide capture system 16 of the present embodiment described above, the fuel supply pipe is located at the center and the oxygen supply pipe is located on the outside thereof, but this is not limited thereto, and the oxygen supply pipe may be located at the center and the fuel supply pipe may be located on the outside thereof.

[0052] Although the embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment, and the above-described embodiment can be modified in various ways without departing from the gist of the present invention.

[0053] For example, the burner 1 may have a plurality of first pipe sections 3. The burner 1 may have a second pipe section 4 surrounding the plurality of first pipe sections 3. The burner 1 may have a plurality of second pipe sections 4. EXAMPLES

[0054] <Example 1 and Example 2> Tables 1 and 2 show the combustion state and the visual flame length when the burner 1 according to the first and second embodiments (second modified example) of the present invention is burned in the air and the flow rate of the natural gas and oxygen as fuel gases supplied to the burner 1 according to the configuration of the present invention is constant and the flow rate of the combustion exhaust gas containing carbon dioxide is changed. The fuel gas used was a gas obtained by vaporizing liquefied natural gas, the oxygen used was oxygen obtained by vaporizing liquefied oxygen with a purity of 99.6% or more, and the combustion exhaust gas containing carbon dioxide was carbon dioxide with a purity of 99.5% or more delivered from a liquefied carbon dioxide container. The flow rate unit Nm 3 The flow rate in m / s and the flow rate in m / s are converted to an atmosphere at 0 degrees Celsius and atmospheric pressure. The oxygen concentration in the combustion supporting gas indicates the ratio of the oxygen flow rate to the flow rate of the combustion supporting gas, which is the sum of the oxygen flow rate and the combustion exhaust gas flow rate. Table 1 shows the combustion results of the burner 1 according to the first embodiment of the present invention as Example 1, and Table 3 shows the design dimensions. Table 2 shows the combustion results of the burner 1 according to the second embodiment (second modified example) of the present invention as Example 2, and Table 4 shows the design dimensions. In either case, a stable burner flame 2 could be obtained, and a similarly stable flame could be obtained under condition 7, in which the amount of combustion exhaust gas mainly composed of carbon dioxide was increased so that the oxygen concentration in the combustion supporting gas was 10%.

[0055] [Table 1]

[0056] [Table 2]

[0057] [Table 3]

[0058] [Table 4]

[0059] <Comparative Example> As a comparative example of the present invention, the combustion state and the length of the flame were confirmed under the same conditions as in the above-mentioned Examples 1 and 2, except that a burner 1 shown in FIG. 7 was used, which uses a mixed gas in which combustion exhaust gas and oxygen are mixed in advance as a combustion supporting gas as shown in Patent Document 1. The results are shown in Table 5. The burner 1 used in the comparative example has the same first tube section 3, second tube section 4 and mixing chamber 15 as in Example 1, does not have the third tube section 7, and is configured so that the second tube section 4 is attached to the through hole 12a of the burner block 12. Moreover, the burner 1 used in the comparative example supplied fuel gas through the first tube section 3 and supplied mixed gas through the second tube section 4. Moreover, the value of L2 / D2 in the burner 1 used in the comparative example was the same as in Example 2. In the comparative example, as shown in Table 5, the flame was blown off and misfired under conditions in which the oxygen concentration in the combustion supporting gas was greater than the above-mentioned 10% in Examples 1 and 2 (see Condition 5).

[0060] [Table 5] [Explanation of symbols]

[0061] 1 Burner 2 Burner flame 3. First Pipe Section 3a 1st inlet 3b tip 4. Second Pipe Section 4a Second entrance 4b Tip 5. Combustion exhaust gas supply section 6 Carbon Dioxide Separator 7. Third Pipe Section 7a 3rd inlet 7b Tip 8 1st supply route 9 2nd supply route 10 Third supply route 11 Burner body 12 Burner block 12a Through hole 12b Combustion exhaust gas supply port 12c supply hole 12d Tip surface 13 Furnace 14 Enclosure 14a Enclosure inlet 14b Connection port 15 Mixing chamber 16 Carbon dioxide capture system 17 Recovery Route 17a cooler 17b Filter 17c denitrifier 17d dehumidifier 18 Combustion exhaust gas supply route 18a Air supply device D1 Inner diameter D2 Inner diameter L1 distance L2 distance R1 radius R2 distance

Claims

1. a first pipe portion that supplies a first gas, which is one of a fuel gas and oxygen, to the burner flame; a second pipe portion surrounding the first pipe portion and supplying a second gas, which is the other of the fuel gas and the oxygen, to the burner flame; a combustion exhaust gas supply section that supplies combustion exhaust gas containing carbon dioxide to the burner flame from a position radially outside of the second tube section.

2. 2. The burner of claim 1, wherein the flue gas supply is formed by a third tubular section surrounding the second tubular section and supplying the flue gas to the burner flame.

3. A burner body having the first tube portion and the second tube portion; A burner block attached to the burner body, 2. The burner of claim 1, wherein the flue gas supply is formed by the burner block.

4. The burner according to claim 3 , wherein the burner block has a combustion exhaust gas supply port of the combustion exhaust gas supply portion adjacent to the second pipe portion in a radial direction of the second pipe portion.

5. The burner according to claim 1 , further comprising a mixing chamber for mixing the first gas and the second gas, the mixing chamber being disposed on a tip side of the tip of the first tube portion.

6. The first pipe section supplies the fuel gas as the first gas at a flow velocity of 12 m / s or more and 80 m / s or less, The second pipe section supplies the oxygen as the second gas at a flow velocity of 5 m / s or more and 30 m / s or less, The burner according to claim 1 , wherein the flue gas supply unit supplies the flue gas at a flow velocity of 10 m / s or less.

7. 2. The burner according to claim 1, wherein the purity of the oxygen supplied from the second tube portion is 90% or more.

8. A burner according to claim 1; A carbon dioxide separator that separates the carbon dioxide; a recovery path for supplying the combustion exhaust gas from a furnace using the burner to the carbon dioxide separation device; a combustion exhaust gas supply path that supplies the combustion exhaust gas before it is supplied from the recovery path to the carbon dioxide separation device to the combustion exhaust gas supply section of the burner.

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