JP2009109067A - Mixed combustion burner and boiler - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a mixed combustion burner, maintaining suitable combustion states (stable ignition performance and combustion stability) to implement reduction in NOx, even when using liquid fuel generated from biomass fuel or waste products. <P>SOLUTION: The mixed combustion burner 100 burning a plurality of sorts of fuel, comprises: a gas combustion part burning gas fuel F0 as primary combustion fuel; and a liquid combustion part burning liquid fuel F2 as second combustion fuel. The combustion gas generated in the gas combustion part is supplied near the liquid combustion part. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a mixed burner and a boiler.

  Conventionally, various burners for burning a plurality of types of fuel are known. As an example, a burner configured to be capable of fueling liquid fuel and gas fuel is known (see, for example, Patent Document 1).

  In such a conventional technique, a configuration in which a gas fuel burner is provided around a liquid fuel burner is disclosed, and the liquid fuel has a boiling point of 100 from the viewpoint of ease of pressure spraying and suppressing generation of soot. A configuration using “kerosene” having a temperature of from 350 ° C. to 350 ° C. is disclosed.

  In recent years, from the viewpoint of energy saving and the like, a technique for effectively using liquid fuel generated from biomass fuel, waste, or the like has been sought. However, since these liquid fuels have different properties such as kinematic viscosity, flash point, and calorific value, when they are burned with the same burner, flame temperature is lowered, problems occur at the time of ignition, and the like. Therefore, soot, CO, and NOx are likely to be generated.

  In the burner according to the prior art, as described above, it is preferable to use “kerosene” as the liquid fuel. Therefore, naturally, it is possible to cope with the liquid fuel generated from the biomass fuel or the waste. Can not. Even if the burner according to the prior art burns the liquid fuel generated from the biomass fuel or the waste, there is a problem that a large amount of soot, CO, and NOx are generated.

JP 2003-294 211 A

  Therefore, the present invention has been made to solve the above-described problems of the prior art, and even when liquid fuel generated from biomass fuel, waste, or the like is used, an appropriate combustion state (stable It is an object of the present invention to provide a mixed burner capable of maintaining low ignition efficiency while maintaining the ignition performance and combustion stability. The present invention has been made to solve the above-mentioned problems of the prior art, and is a case where liquid fuel generated from biomass fuel, waste, or the like by using the above-described burner is used. It is another object of the present invention to provide a boiler capable of maintaining a suitable combustion state (stable ignition performance, combustion stability) and reducing NOx.

  The present invention has been made in order to solve the above problems, and is a mixed combustion burner capable of burning a plurality of types of fuel, a gas combustion section for burning gaseous fuel which is a primary combustion fuel, and a secondary combustion fuel A liquid combustion section for burning the liquid fuel, and the combustion gas generated in the gas combustion section is supplied to the vicinity of the liquid combustion section.

That is, in the present invention, the first stage combustion is performed in the gas combustion section, and the second stage combustion is performed in the liquid combustion section. In addition, in this invention, the combustion gas produced | generated in the gas combustion part will be supplied to a liquid combustion part (and its vicinity). According to such a configuration, the ignition performance and combustion stability in the liquid combustion section (liquid fuel) are enhanced by the preheating of the combustion gas generated in the gas combustion section. Therefore, according to such a structure, the mixed combustion burner which can respond to a wide range of liquid fuels (for example, liquid fuel produced | generated from biomass fuel, a waste material, etc.) can be obtained.
Moreover, according to such a structure, the combustion gas produced | generated in the gas combustion part is supplied to a liquid combustion part, The effect substantially the same as exhaust gas recirculation (EGR) is acquired, and NOx reduction is achieved. Can be planned.
Furthermore, according to such a configuration, multi-stage combustion is performed in the gas combustion section and the liquid combustion section, so that NOx reduction can be achieved.

  Further, in the mixed combustion burner according to the present invention, the gas combustion section is configured to burn a premixed fuel in which the gaseous fuel and primary combustion fuel air are mixed, and the primary combustion fuel air is used as the primary combustion fuel air. A configuration in which more air than the theoretical air amount is supplied is preferable.

  According to this preferable configuration, since the premixed lean combustion is performed in the gas combustion section, NOx reduction can be achieved.

  Furthermore, in the mixed combustion burner according to the present invention, the gas combustion section is configured to burn a premixed fuel in which the gaseous fuel and primary combustion fuel air are mixed, and the primary combustion fuel air is used as the primary combustion fuel air. A configuration in which air in which the residual oxygen concentration of the combustion gas generated in the gas combustion section is 5% to 10% is supplied is preferable.

  According to this preferable configuration, since the premixed lean combustion is performed in the gas combustion section, NOx reduction can be achieved.

  In addition, the present invention has been made to solve the above-described problem, and has a can body having an inner water tube group and an outer water tube group arranged in an annular shape, and is disposed at a central portion of the inner water tube group. A boiler including a burner, wherein the burner is a mixed-burning burner according to any one of the above-described configurations.

  According to the boiler according to such a configuration, since the mixed combustion burner capable of exhibiting the various effects described above is mounted, even when liquid fuel generated from biomass fuel or waste is used, A boiler capable of maintaining an appropriate combustion state (stable ignition performance, combustion stability) and reducing NOx can be obtained.

  Furthermore, the present invention has been made in order to solve the above-described problem, and has a can body having an inner water tube group and an outer water tube group arranged in a ring shape, and is disposed at a central portion of the inner water tube group. A boiler having a burner, wherein adjacent inner water tubes forming the inner water tube group are closed except for a portion where a gas flow channel is provided, and the gas flow channel is annular on one end side of the inner water tube group The burner is a mixed burner according to any one of the above-described configurations.

  According to such a configuration, since the mixed combustion burner capable of exhibiting the various effects described above is mounted, proper combustion is possible even when liquid fuel generated from biomass fuel, waste, or the like is used. A boiler capable of maintaining the state (stable ignition performance, combustion stability) and reducing NOx can be obtained. In addition, according to such a configuration, a gap between adjacent inner water tubes forming the inner water tube group is closed except for a portion where a gas flow channel is provided, and the gas flow channel is annularly connected to one end side of the inner water tube group. Therefore, the combustion gas flows uniformly to one end side (upper side or lower side) of the inner water tube group. That is, according to such a configuration, the gas generated in the burner flows evenly in the gas flow path, so that the combustion state in the can body is stabilized, more effectively improving the flammability and harmful substances The boiler which can implement | achieve reduction of can be obtained.

  Moreover, in the boiler concerning this invention, the structure by which the expanded heat-transfer surface is provided in at least one of the said inner side water pipe group and the said outer side water pipe group in the said gas flow path vicinity is preferable.

  According to this preferred configuration, an enlarged heat transfer surface is provided in the vicinity of the gas flow path, heat recovery is performed from the combustion gas at an early stage, and the combustion gas temperature is lowered early, thereby reducing the generation of thermal NOx. Is possible.

  According to the present invention, even when liquid fuel generated from biomass fuel, waste, or the like is used, an appropriate combustion state (stable ignition performance, combustion stability) is maintained, and NOx reduction is achieved. A co-fired burner that can be achieved can be obtained. Further, according to the present invention, by using the above-mentioned mixed combustion burner, even when liquid fuel generated from biomass fuel, waste, or the like is used, an appropriate combustion state (stable ignition performance, stable combustion) Therefore, it is possible to obtain a boiler capable of reducing NOx.

  Before describing the embodiments of the present invention, terms used in this specification will be described.

  In the present specification, when simply referred to as “gas”, the gas is a concept including at least one of a gas during a combustion reaction and a gas for which the combustion reaction has been completed, and may also be referred to as a combustion gas. In other words, the gas includes both the gas in the combustion reaction and the gas in which the combustion reaction is completed, the gas in the combustion reaction only, or the gas in which the combustion reaction is completed only. It is a concept that includes. Hereinafter, the same concept is used unless otherwise described.

  Further, the exhaust gas means a gas in which the combustion reaction is completed or almost completed. Further, unless otherwise specified, exhaust gas means either or both of the gas that passes through the boiler body and reaches the chimney and the gas that circulates in the body.

  Further, the gas temperature means the temperature of the gas during the combustion reaction unless otherwise specified, and is synonymous with the combustion temperature or the combustion flame temperature. Further, the suppression of the gas temperature means that the maximum value of the gas (combustion flame) temperature is kept low. In general, the combustion reaction is extremely small in the above-mentioned “gas for which the combustion reaction has been completed”, but continues, so “completion of the combustion reaction” means 100% completion of the combustion reaction. It is not a thing.

  Hereinafter, embodiments of the present invention will be described.

  First, the first aspect of the present embodiment is a co-burning burner capable of burning a plurality of types of fuel, a gas combustion section for burning gaseous fuel that is primary combustion fuel, and a liquid fuel that is secondary combustion fuel And a combustion gas generated in the gas combustion unit is supplied to the vicinity of the liquid combustion unit.

  Moreover, the 2nd aspect of this embodiment is comprised so that the said gas combustion part may burn the premixed fuel with which the said gaseous fuel and the air for primary combustion fuels were mixed in the mixed combustion burner concerning a 1st aspect. The primary combustion fuel air is configured to supply more air than the theoretical air amount.

  Further, according to a third aspect of the present embodiment, in the mixed combustion burner according to the first aspect or the second aspect, the gas combustion unit burns a premixed fuel in which the gaseous fuel and primary combustion fuel air are mixed. The primary combustion fuel air is configured to be supplied with air in which the residual oxygen concentration of the combustion gas generated in the gas combustion section is 5% to 10%.

  The fourth aspect of the present embodiment is a boiler including a can having an inner water tube group and an outer water tube group arranged in an annular shape, and a burner disposed in a central portion of the inner water tube group. And the said burner is a mixed-burning burner concerning the structure in any one of a 1st aspect to a 3rd aspect, It is characterized by the above-mentioned.

  Furthermore, a fifth aspect of the present embodiment is a boiler including a can having an inner water tube group and an outer water tube group arranged in an annular shape, and a burner disposed at a central portion of the inner water tube group. The adjacent inner water pipes forming the inner water pipe group are closed except for a portion where a gas flow path is provided, and the gas flow path is provided in an annular shape on one end side of the inner water pipe group, and the burner However, it is the mixed combustion burner concerning the structure in any one of a 1st aspect to a 3rd aspect, It is characterized by the above-mentioned.

  Further, according to a sixth aspect of the present embodiment, in the boiler according to the fifth aspect, an enlarged heat transfer surface is provided on at least one of the inner water tube group and the outer water tube group in the vicinity of the gas flow path. It is a feature.

<First Example>
Hereinafter, the boiler concerning the 1st example of the present invention is explained based on a drawing.

  FIG. 1 shows an explanatory view of a longitudinal section of a boiler according to a first embodiment of the present invention. FIG. 2 shows a simplified explanatory view of a cross section taken along line II-II in FIG. FIG. 3 shows a simplified explanatory view of a cross section taken along line III-III in FIG. FIG. 4 shows a simplified explanatory view of a cross section taken along line IV-IV in FIG.

  As shown in FIG. 1 etc., the boiler 1 concerning a present Example is comprised using the can 10 which has the water pipe group arranged in cyclic | annular form, and the burner 100 arrange | positioned in the center part of these water pipe groups. A wind box 70 for supplying combustion air to the burner 100 is provided above the burner 100.

  The can body 10 is configured by standing a plurality of water pipe groups (an inner water pipe group 20 and an outer water pipe group 30) between the upper header 11 and the lower header 12. The respective water tube groups 20 and 30 are arranged in a substantially concentric ring shape, and an outer water tube group 30 is provided at a predetermined interval from the inner water tube group 20, and the inner water tube group 20 and the outer water tube group 30 An annular gas flow path 80 is formed between the two.

  In the present embodiment, the inner water tube group 20 is configured using a plurality of inner water tubes 21 and first vertical fin portions 24. Each inner water pipe 21 is formed in an annular shape with a substantially uniform predetermined interval, and a first vertical fin connected between each inner water pipe 21 so as to eliminate a gap between adjacent inner water pipes 21. A portion 24 is provided. That is, in the present embodiment, the inner water tube group 20 is configured in an annular shape in close contact with the first vertical fin portion 24.

  Moreover, the lower end part 21a of each inner side water pipe 21 is a reduced diameter part, and in the inner side water pipe group 20 concerning a present Example, the space around this reduced diameter lower end part 21a is the inner side formed circularly. It will function as the gas channel 25 (corresponding to the “gas channel” of the present invention). That is, the inner gas channel 25 functions to guide the gas generated inside the inner water tube group 20 to the annular gas channel 80.

  In the present embodiment, the outer water tube group 30 is configured using a plurality of outer water tubes 31 and a second vertical fin portion 34. Each outer water pipe 31 is formed in an annular shape with a substantially uniform predetermined interval, and a second vertical fin connected to each other to eliminate a gap between adjacent outer water pipes 31. A portion 34 is provided. That is, in the present embodiment, the outer water pipe group 30 is configured in an annular shape in a close state using the second vertical fin portion 34.

  Further, as shown in FIG. 1, the second vertical fin portion 34 connected between the outer water pipes 31 is provided so as to have a predetermined space with the heat insulating material provided on the upper portion of the inner wall of the can body 10. In the outer water tube group 30 according to the present embodiment, a space formed above the second vertical fin portion 34 (a space formed between the second vertical fin portion 34 and the upper heat insulating material). However, it functions as the outer gas channel 35 formed in an annular shape. The outer gas channel 35 functions to guide the gas introduced into the annular gas channel 80 toward the exhaust cylinder 90. That is, the gas generated inside the inner water tube group 20 is collected in the exhaust pipe 90 via the inner gas flow path 25, the annular gas flow path 80, and the outer gas flow path 35, and the can is It is discharged outside the body 10.

  Each inner water pipe 21 constituting the inner water pipe group 20 has a plurality of first stud fins 22 (corresponding to the “expanded heat transfer surface” of the present invention) above the lower end 21a (in the vicinity of the inner gas flow path 25). Is provided. More specifically, a plurality of first stud fins are formed from a substantially central portion of each inner water pipe 21 facing the annular gas flow path 80 to a lower position (downstream of the lower end portion 21a (downstream of the gas flow)). 22 is provided. The inner water pipe 21 located on the downstream side (downstream side of the gas flow) where the first stud fins 22 are provided has a plurality of flat plate-like first fins 23 (flat plate shape) on the annular gas flow path 80 side. Fins).

  Each of the outer water pipes 31 constituting the outer water pipe group 30 is provided with a plurality of second stud fins 32 (corresponding to the “expanded heat transfer surface” of the present invention) in the vicinity of the inner gas flow path 25. More specifically, a plurality of second stud fins 32 are provided from a substantially central portion of each outer water pipe 31 facing the annular gas flow path 80 to a lower position. The outer water pipe 31 located on the downstream side (downstream side of the gas flow) where the second stud fins 32 are provided has a plurality of flat plate-like second fins 33 (flat plate shape) on the annular gas flow path 80 side. Fins).

  That is, in the present embodiment, the stud fins (first stud fins 22) are connected to the inner water pipe group 20 (the inner water pipe 21 constituting the inner water pipe group 20) and the outer water pipe group 30 (the outer water pipe 31 constituting the outer water pipe group 30) in the vicinity of the inner gas flow path 25. , Second stud fins 32) are provided, and flat fins (first fins 23, second fins 33) are provided downstream of these stud fins (downstream in the gas flow). In the present embodiment, the first fin 23 and the second fin 33 are inclined at an angle of about 20 ° to 85 ° with respect to the gas flow (vertical flow) (an inclination of about 5 ° to 70 ° with respect to the horizontal). Angle).

  5 and 6 are schematic views of the mixed burner provided in the boiler according to the present embodiment. Here, FIG. 5 shows an explanatory view of a longitudinal section of the mixed combustion burner according to the present embodiment, and FIG. 6 shows a bottom view of the mixed combustion burner shown in FIG.

  The mixed combustion burner 100 constituting the boiler 1 according to the present embodiment is installed in a partition wall 71 in a wind box 70 as an air supply means for supplying combustion air to the mixed combustion burner 100 (FIGS. 1 and 5). reference). Specifically, the mounting plate 101 constituting the mixed burner 100 is mounted on the partition wall 71 from above, and the mounting plate 101 is fastened to the partition wall 71 with fastening means (not shown) such as bolts. The mixed burner 100 is installed on the partition wall 71 in the wind box 70. In the present embodiment, the configuration of the blower that supplies air into the wind box 70 is omitted because it is a well-known technique.

  The burner according to the present embodiment is a mixed combustion burner 100 capable of burning a plurality of types of fuel, and includes a gas combustion portion that burns gaseous fuel that is primary combustion fuel, and a liquid that burns liquid fuel that is secondary combustion fuel. A combustion unit, and the combustion gas generated in the gas combustion unit is configured to be supplied to the vicinity of the liquid combustion unit.

  The co-fired burner 100 according to the present embodiment includes an outer cylinder part 111, a metal knit burner part 112 provided so as to be connected to the outer cylinder part 111, a guide part 113 provided on the lower inner side of the metal knit burner part 112, Inner cylinder part 121 provided on the inner side of outer cylinder part 111 and metal knit burner part 112, burner nozzle part 122 provided on the inner side of inner cylinder part 121, and baffle plate provided in the vicinity of the tip of this burner nozzle part 122 123 or the like.

  In the present embodiment, a region configured between the outer cylinder portion 111 and the inner cylinder portion 121 functions as the first premixed fuel flow path 115, and is between the metal knit burner portion 112 and the inner cylinder portion 121. The region configured as (1) functions as the second premixed fuel flow path 117. A region formed between the inner cylinder part 121 and the burner nozzle part 122 functions as the air flow path 127.

  The gas combustion part which comprises the mixed combustion burner 100 concerning a present Example is comprised so that the gaseous fuel F0 which is a primary combustion fuel may be burned, Specifically, gaseous fuel F0 and the primary combustion fuel air A0 are comprised. The mixed premixed fuel F1 is ejected from the metal knit burner portion 112 and burned (premixed lean combustion). As shown in FIG. 5 and the like, the gas combustion part includes an outer cylinder part 111, a metal knit burner part 112 provided so as to be connected to the outer cylinder part 111, and a guide provided below the metal knit burner part 112. Part 113, first premixed fuel flow path 115, second premixed fuel flow path 117, and the like. In the present embodiment, for example, LPG, city gas or the like is used as the gaseous fuel F0.

  The metal knit burner portion 112 is provided with a large number of fine ejection hole portions on the entire surface of the cylinder, and the configuration thereof is not particularly limited. For example, the metal knit burner unit 112 may be configured by laminating a plurality of wire meshes and winding them into a cylindrical shape. Further, for example, the metal knit burner portion 112 may be configured by stacking a plurality of disk-shaped members having uneven portions on the surface in the vertical direction. Further, for example, the metal knit burner 112 may be configured by drilling minute holes on the entire surface of a metal cylinder.

  The guide portion 113 is provided so as to have a predetermined angle so that the premixed fuel F <b> 1 flowing into the second premixed fuel flow channel 117 is uniformly ejected from the metal knit burner portion 112.

  The liquid combustion part that constitutes the mixed combustion burner 100 according to the present embodiment is configured to burn the liquid fuel F2 that is the secondary combustion fuel. Specifically, the liquid fuel F2 ejected from the burner nozzle part 122 and The secondary fuel combustion air A2 is mixed and held in the vicinity of the baffle plate 123 to burn and burn. As shown in FIG. 5 etc., the liquid combustion part is comprised using the inner cylinder part 121, the burner nozzle part 122, the baffle plate 123, the air flow path 127 grade | etc.,. In the present embodiment, as the liquid fuel F2, for example, liquid fuel generated from ethanol, biomass fuel, waste, or the like, waste oil, or the like is used.

  The baffle plate 123 is provided with an ejection hole portion 123a at the center thereof so as to allow the liquid fuel F2 ejected from the burner nozzle portion 122 to pass therethrough. Further, a plurality of (eight in this embodiment) slit portions 123b are provided radially from the ejection hole portion 123a. The baffle plate 123 configured in this manner disturbs the flow of the secondary combustion fuel air A2 ejected via the air flow path 127, and effectively uses the secondary combustion fuel air A2 and the liquid fuel F2. It creates a proper mixed state and functions to properly hold the combustion gas (flame).

  The boiler 1 concerning a present Example is comprised as mentioned above, and acts as follows based on the structure. Hereinafter, the operation will be specifically described with reference to FIGS.

  When operating the mixed combustion burner 100 according to the present embodiment, first, a blower (not shown) is driven, and the primary combustion fuel air A0 and the secondary combustion fuel air A2 are passed through the wind box 70, The first premixed fuel flow path 115, the second premixed fuel flow path 117, and the air flow path 127 are supplied. In the gas combustion section, gaseous fuel F0, which is the primary combustion fuel, is supplied in accordance with the ignition timing. As a result, the first premixed fuel flow path 115 and the second premixed fuel flow path 117 are The premixed fuel F1 obtained by mixing the primary combustion fuel air A0 and the gaseous fuel F0 is supplied. That is, in the present embodiment, the igniter (not shown) is energized in accordance with the supply timing of the premixed fuel F1 (which constitutes the gaseous fuel F0).

  At this time, in the gas combustion unit according to the present embodiment, more air than the theoretical air amount is supplied according to the supplied gaseous fuel F0. More specifically, the first premixed fuel flow path 115 and the second premixed fuel flow path 117 constituting the gas combustion section are generated by the gas combustion section (the metal knit burner section 112 constituting the gas combustion section). Air is supplied so that the residual oxygen concentration of the combustion gas is 5% to 10%. That is, in this embodiment, premixed lean combustion is performed in the metal knit burner portion 112 that constitutes the gas combustion portion.

  Next, in the present embodiment, the liquid fuel F2 is sprayed in a hollow cone shape from the burner nozzle portion 122, and mixing of the secondary combustion fuel air A2 and the liquid fuel F2 supplied via the air flow path 127 described above is performed. Done. The liquid fuel F2 thus mixed is ignited while being preheated by the combustion gas from the already ignited gas combustion part, and in the liquid combustion part, a flame (combustion gas) is generated in the vicinity of the baffle plate 123. The flame is held.

  In the mixed combustion burner 100 according to the present embodiment, combustion is performed by appropriately controlling at least one of the supply pressure of the gaseous fuel F0 supplied to the gas combustion unit and the supply pressure of the liquid fuel F2 supplied to the liquid combustion unit. The amount can be adjusted. That is, for example, the mixed combustion burner 100 can be configured to switch to any one of the stopped state, the low combustion state, and the high combustion state.

  The amount of air supplied to the mixed burner 100 is generally adjusted using a damper (not shown) provided in a duct between the wind box 70 and the blower, an inverter for controlling the rotation speed of the blower, or the like (not shown). Is done. And this air is supplied corresponding to the supply amount of gaseous fuel and liquid fuel. As described above, in this embodiment, since a large amount of air is supplied to the gas combustion section, premixed lean combustion is performed in the gas combustion section, and rich combustion is performed in the liquid combustion section. Will be performed. And as the whole mixed-burner 100, a combustion state will be maintained by the appropriate air quantity as needed.

  In the mixed combustion burner 100 configured and functioning as described above, combustion gas (flame) (not shown) is formed in the vicinity of the metal knit burner portion 112 and the baffle plate 123 shown in FIG. It will be. Then, the combustion gas G0 generated in the mixed combustion burner 100 flows downward along the inner water tube group 20. The gas that has flowed downward along the inner water tube group 20 collides with the lower surface of the can body 10, and then becomes a flow of gas G1 (see FIGS. 1 and 2) that flows radially in the circumferential direction. It is introduced into the annular gas flow path 80 through the inner gas flow path 25.

  The gas G <b> 2 introduced into the annular gas channel 80 via the inner gas channel 25 then flows upward along the inner water tube group 20 and the outer water tube group 30. At this time, the gas G2 flows upward according to the inclination angle of the flat fins (first fin 23, second fin 33) provided in the inner water tube group 20 and the outer water tube group 30. Then, the gas G2 that has flowed upward collides with the upper surface of the can 10 and then becomes a flow of gas G3 (see FIGS. 1 and 4) that flows radially in the circumferential direction. The gas is collected in the exhaust cylinder 90 through 35 and discharged to the outside of the can body 10 through the exhaust cylinder 90.

  In the gas flow as described above, the thermal energy of the flame (combustion gas) generated by the mixed combustion burner 100 is recovered by the inner water tube group 20 and the outer water tube group 30.

  More specifically, first, the gas G0, G1 and the inner surface of the inner water tube group 20 are in contact with each other on the inner surface side of the inner water tube group 20 (the side where the mixed combustion burner 100 is provided (combustion chamber side)). Thus, heat recovery is performed. Next, when the gas G1 passes through the inner gas flow path 25, the inner water pipe group 20 (the lower end portion 21a of the inner water pipe 21 constituting the gas pipe G1) and the gas G1 come into contact with each other to recover heat.

  Next, after the gas G1 passes through the inner gas passage 25, the gas collides with the lower end of the outer water tube group 30, and in addition, stud fins 22 and 32 are provided in the vicinity of the inner gas passage 25. Therefore, a turbulent state is promoted in the vicinity of the inner gas flow path 25. Therefore, in the vicinity of the inner gas flow path 25, the first stud fins 22 and the second stud fins 32 are effectively brought into contact with the gas, and highly efficient heat recovery is performed.

  Next, the gas G2 flowing upward in the annular gas channel 80 is supplied to the inner water tube group 20, the outer water tube group 30, and the flat fins (the first fin 23, the first fin provided in each of the water tube groups 20, 30). Heat recovery from the gas G2 is performed by contacting the two fins 33) and making contact therewith. Finally, the gas G3 that has flowed upward in the annular gas flow path 80 contacts the outside of the outer water tube group 30 (exhaust pipe 90 side) until it is collected in the exhaust pipe 90 via the outer gas flow path 35. By doing so, heat recovery is performed.

  Since the mixed burner 100 and the boiler 1 according to this embodiment are configured and function as described above, the following effects can be obtained.

  The co-firing burner 100 according to the present embodiment includes a gas combustion unit that combusts the gaseous fuel F0 that is the primary combustion fuel, and a liquid combustion unit that combusts the liquid fuel F2 that is the secondary combustion fuel. The generated combustion gas is configured to be supplied to the vicinity of the liquid combustion unit. That is, in the present embodiment, the first stage combustion is performed in the gas combustion section, and the second stage combustion is performed in the liquid combustion section. In addition, in the present embodiment, the combustion gas generated in the gas combustion unit is supplied to the liquid combustion unit (and the vicinity thereof).

  According to such a configuration, ignition performance and combustion stability in the liquid combustion section (liquid fuel F2) are increased by preheating the combustion gas generated in the gas combustion section. Therefore, according to such a structure, the mixed combustion burner 100 which can respond to a wide range of liquid fuel F2 (for example, liquid fuel produced | generated from biomass fuel, a waste material, etc.) can be obtained. Moreover, according to such a structure, the combustion gas produced | generated in the gas combustion part is supplied to a liquid combustion part, The effect substantially the same as exhaust gas recirculation (EGR) is acquired, and NOx reduction is achieved. You can plan. Furthermore, according to such a configuration, multi-stage combustion is performed in the gas combustion section and the liquid combustion section, so that NOx reduction can be achieved.

  Further, in the mixed combustion burner 100 according to the present embodiment, the gas combustion unit is configured to burn the premixed fuel F1 in which the gaseous fuel F0 and the primary combustion fuel air A0 are mixed. The air A0 is configured to supply more air than the theoretical air amount.

  According to such a configuration, since premixed lean combustion is performed in the gas combustion section, NOx reduction can be achieved.

  Furthermore, in the mixed combustion burner 100 according to the present embodiment, the gas combustion unit is configured to burn the premixed fuel F1 in which the gaseous fuel F0 and the primary combustion fuel air A0 are mixed, and is used for the primary combustion fuel. The air A0 is configured to be supplied with air in which the residual oxygen concentration of the combustion gas generated in the gas combustion section is 5% to 10%.

  According to such a configuration, since premixed lean combustion is performed in the gas combustion section, NOx reduction can be achieved.

  Further, the boiler 1 according to the present embodiment includes a can body 10 having an inner water tube group 20 and an outer water tube group 30 arranged in an annular shape, and a burner disposed in a central portion of the inner water tube group 20. It is a boiler 1, Comprising: This burner is the mixed combustion burner 100 concerning one of the structures mentioned above, It is characterized by the above-mentioned.

  According to the boiler 1 having such a configuration, since the mixed combustion burner 100 capable of exhibiting the various effects described above is mounted, it is a case where liquid fuel generated from biomass fuel, waste, or the like is used. However, it is possible to obtain the boiler 1 that can maintain an appropriate combustion state (stable ignition performance, combustion stability) and achieve low NOx.

  Furthermore, the boiler 1 according to the present embodiment includes a can body 10 having an inner water tube group 20 and an outer water tube group 30 arranged in an annular shape, and a burner disposed in a central portion of the inner water tube group 20. In the boiler 1, between adjacent inner water tubes constituting the inner water tube group 20 is closed except for a portion where the inner gas flow channel 25 (gas flow channel) is provided, and the inner gas flow channel 25 is formed in the inner water tube group 20. The burner is provided in an annular shape on the lower end side, and this burner is a mixed-burning burner 100 according to any one of the above-described configurations.

  According to such a configuration, since the mixed combustion burner 100 capable of exhibiting the various effects described above is mounted, even when liquid fuel generated from biomass fuel, waste, or the like is used, it is appropriate. A boiler capable of maintaining a combustion state (stable ignition performance, combustion stability) and reducing NOx can be obtained. In addition, according to such a configuration, the adjacent inner water tubes forming the inner water tube group 20 are closed except for the portion where the inner gas flow channel 25 is provided, and the inner gas flow channel 25 is closed at the lower end of the inner water tube group 20. Since it is provided in a ring shape on the side, the combustion gas flows evenly to the lower end side of the inner water tube group 20. In other words, according to such a configuration, the gas generated in the mixed combustion burner 100 flows evenly into the inner gas flow path 25, so that the combustion state in the can 10 is stabilized and more effectively combustible. A boiler capable of improving and reducing harmful substances can be obtained.

  In the boiler 1 according to this embodiment, the stud fins 22 and 32 (enlarged heat transfer surfaces) are provided in the inner water tube group 20 and the outer water tube group 30 in the vicinity of the inner gas flow path 25. That is, the boiler 1 is configured as described above, and the gas flows in the can body 10 as described above, so that heat recovery is effectively performed and an extended heat transfer surface (fin or the like) having high durability is provided. The boiler 1 provided with the water pipe group which has can be obtained.

  Specifically, according to the boiler 1 according to the present embodiment, the stud fins 22 and 32 (enlarged heat transfer surfaces) are provided in the vicinity of the inner gas channel 25 (gas channel), which is a region where the temperature difference is large. Therefore, heat recovery can be performed effectively. In addition, since the enlarged heat transfer surfaces provided in the vicinity of the inner gas flow path 25 are the stud fins 22 and 32, even if an overheated state occurs, cracks, dropouts, and the like are unlikely to occur. Further, according to such a configuration, the stud fins 22 and 32 are provided in the vicinity of the inner gas flow path 25, and heat recovery is performed from the combustion gas at an early stage, and the temperature of the combustion gas is lowered early. Can be reduced.

  Further, in the boiler 1 according to the present embodiment, flat fins 23 and 33 inclined with respect to the gas flow are provided on the downstream side of the stud fins 22 and 32 provided in the vicinity of the inner gas flow path 25. It has been. According to such a configuration, it becomes possible to configure the boiler 1 that can be recovered more effectively and operated with high efficiency without wasting the heat energy that could not be recovered by the stud fins 22 and 32. .

  Further, in the boiler 1 according to the present embodiment, the plate-like fins 23 and 33 provided on the downstream side of the stud fins 22 and 32 are provided to be inclined at a predetermined angle with respect to the gas flow. The inside of the annular gas flow path 80 is raised. That is, according to the present embodiment, compared to the case where fins are provided at right angles to the gas flow, the fins 23 and 33 do not obstruct the gas flow, so that the boiler 1 capable of realizing a low pressure loss can be obtained. .

  Furthermore, according to the boiler 1 according to the present embodiment, as described above, it is possible to effectively recover the heat, so that it is possible to reduce the size of the boiler. . That is, by increasing the heat recovery rate, it is possible to increase the operating efficiency of the boiler, and accordingly, the boiler can be reduced in size.

<Other examples>
The present invention is not limited to the above-described embodiments and examples (hereinafter referred to as “the above-described embodiments and the like”), and various modifications are made as necessary within the scope that can meet the gist of the present invention. It is also possible to implement them, and they are all included in the technical scope of the present invention.

  For example, the boiler 1 according to the present invention is not limited to the structure of the can 10 described with reference to FIG. 1 and the like, and various modifications can be made as necessary. Therefore, for example, a configuration as shown in FIG. Here, FIG. 7 shows a simplified explanatory view of a transverse section of a boiler according to another embodiment of the present invention.

  A boiler according to another embodiment has the same basic configuration as that of the first embodiment described above. Therefore, in the following, the same parts as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and the detailed description thereof is omitted, and the configuration different from the first embodiment will be mainly described. .

  FIG. 7 shows a simplified explanatory view of a cross section of a boiler according to another embodiment of the present invention. More specifically, it is a simplified explanatory diagram corresponding to FIG. 2 according to the first embodiment described above. That is, FIG. 7 shows a simplified explanatory view of a cross section in the vicinity of the inner gas flow path 25 (corresponding to the “gas flow path” of the present invention) of the boiler according to the present embodiment.

  As described above, the boiler 1 according to the present embodiment basically has the same configuration as that of the first embodiment, and the difference from the first embodiment is that the inner gas flow path 25 is in the vicinity. It is the number of stud fins provided. In the present embodiment, more second stud fins 32 are provided at the lower end of the outer water pipe 31 than in the first embodiment.

  As described in the first embodiment, after the gas G <b> 1 passes through the inner gas passage 25, the gas collides with the lower end portion of the outer water tube group 30. After that, in the vicinity of the inner gas flow path 25, the gas mainly flows upward along the outer water tube group 30. If so, it is possible to increase the number of contact with the gas by providing more stud fins (second stud fins 32) in the outer water tube group 30 in the vicinity of the inner gas flow path 25.

  A present Example is comprised paying attention to this gas flow, and aims at providing the boiler 1 which can perform heat recovery with higher efficiency.

  As described above, the boiler according to the present embodiment is provided with the stud fins 22 and 32 in the inner water tube group 20 and the outer water tube group 30 in the vicinity of the inner gas flow path 25, and more than the outer water tube group 30. Stud fins are provided.

  According to the boiler 1 according to the present embodiment, after the combustion gas generated in the burner 100 provided in the central portion of the inner water tube group 20 contacts the outer water tube group 30 via the inner gas passage 25, It circulates between water pipe groups (between the inner water pipe group 20 and the outer water pipe group 30) (annular gas flow path 80). At this time, the gas continuously flows from the inner water tube group 20 toward the outer water tube group 30, so in the annular gas flow path 80, the gas contact time is inevitably higher in the outer water tube group 30 than in the inner water tube group 20. Will be longer. According to the present embodiment, the outer water tube group 30 is provided with more stud fins than the inner water tube group 20, and therefore heat recovery from the combustion gas can be performed more effectively.

  Moreover, according to the boiler 1 concerning this other Example, in addition to the said effect, the effect obtained in a 1st Example can also be naturally obtained.

  Further, in the above-described embodiment and the like, the case where the stud fins 22 and 32 are provided in both the inner water tube group 20 and the outer water tube group 30 in the vicinity of the inner gas channel 25 (gas channel) has been described. It is not limited to the configuration. Therefore, for example, it is good also as a structure which provides a stud fin only in the outer side water pipe group 30 in the inner side gas flow path 25 vicinity. As described above, since the gas continuously flows from the inner water tube group 20 toward the outer water tube group 30, the gas contact time in the annular gas flow path 80 is longer than that of the inner water tube group 20. Will be longer. Therefore, even when the stud fin is provided only in the outer water tube group 30 in the vicinity of the inner gas flow path 25 in this way, heat recovery from the combustion gas can be performed relatively effectively.

  Further, in the above-described embodiment and the like, the case where the boiler is configured using a can body in which two rows of water pipe groups are arranged substantially concentrically has been described, but the present invention is not limited to this configuration, and as necessary. In addition, the can body may be configured by arranging three or more groups of water tubes. If a can body is configured by arranging three rows of water tube groups (for example, an inner water tube group, an intermediate water tube group, and an outer water tube group) in a substantially concentric circle, one end side (for example, the lower end side) of the inner water tube group If the inner gas flow path is provided in the intermediate water pipe group, the intermediate gas flow path is provided on the other end side (for example, the upper end side), and the outer gas flow is provided on one end side (for example, the lower end side) of the outer water pipe group. It is preferable to do.

  Furthermore, in the above-described embodiment and the like, a case where a boiler is configured using a can body in which two rows of water tube groups are arranged substantially concentrically, a so-called “round can body” has been described. However, the boiler may be configured using a “square can” as necessary. That is, the above-described mixed burner 100 may be applied to the boiler of this “square can body”. Here, the “square can body” is, for example, configured by accommodating a can body composed of a plurality of parallel water pipe rows in a square housing or casing, and includes a blower, a water supply pump, It is a can that has been devised so that the entire structure becomes a very thin structure by assembling equipment such as a burner.

  Moreover, in the said embodiment etc., although the case where the cylindrical stud fins 22 and 32 were used was demonstrated, this invention is not limited to this structure, The protrusion with high durability which can be welded appropriately to a water pipe Any shape may be used as long as it is a thing. Therefore, for example, an oblique cylinder shape, an elliptic cylinder shape (including an oblique elliptic cylinder shape), a prismatic shape (including an oblique prism shape), a cone shape (including an oblique cone shape), a pyramid shape (including an oblique pyramid shape), etc. Stud fins having the following shape may be used.

It is explanatory drawing of the longitudinal cross-section of the boiler concerning the 1st Example of this invention. FIG. 2 is a simplified explanatory diagram of a cross section taken along line II-II in FIG. 1. FIG. 3 is a simplified explanatory diagram of a cross section taken along line III-III in FIG. 1. FIG. 4 is a simplified explanatory diagram of a cross section taken along line IV-IV in FIG. 1. The explanatory view of the longitudinal section of the mixed combustion burner concerning the first example of the present invention is shown. FIG. 6 is a bottom view of the mixed burner shown in FIG. 5. It is a simplified explanatory drawing of the cross section of the boiler concerning the other Example of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Boiler 10 ... Can body 11 ... Upper header 12 ... Lower header 16 ... Combustion chamber 20 ... Inner water pipe group 21 ... Inner water pipe 21a ... Lower end part 22 ... First stud fin 23 ... First fin (flat fin)
24 ... first vertical fin part 25 ... inner gas flow path 30 ... outer water pipe group 31 ... outer water pipe 32 ... second stud fin 33 ... second fin (flat fin)
34 ... Second vertical fin part 35 ... Outer gas flow path 70 ... Wind box 71 ... Bulkhead 80 ... Annular gas flow path 90 ... Exhaust pipe 100 ... Burner 101 ... Mounting plate 111 ... Outer cylinder part 112 ... Metal knit burner part 113 DESCRIPTION OF SYMBOLS ... Guide part 115 ... 1st premix fuel flow path 117 ... 2nd premix fuel flow path 121 ... Inner cylinder part 122 ... Burner nozzle part 123 ... Baffle plate 123a ... Injection hole part 123b ... Slit part 127 ... Air flow path

Claims (6)

A mixed burner capable of burning multiple types of fuel,
A gas combustion section for burning a gaseous fuel that is a primary combustion fuel, and a liquid combustion section for burning a liquid fuel that is a secondary combustion fuel,
A mixed combustion burner characterized in that combustion gas generated in the gas combustion section is supplied in the vicinity of the liquid combustion section. The gas combustion unit is configured to burn a premixed fuel in which the gaseous fuel and primary combustion fuel air are mixed,
The co-firing burner according to claim 1, wherein more air than the theoretical air amount is supplied as the primary combustion fuel air. The gas combustion unit is configured to burn a premixed fuel in which the gaseous fuel and primary combustion fuel air are mixed,
The co-firing burner according to claim 1 or 2, wherein air for supplying a residual oxygen concentration of the combustion gas generated in the gas combustion section of 5% to 10% is supplied as the primary combustion fuel air. A boiler comprising a can having an inner water tube group and an outer water tube group arranged in an annular shape, and a burner disposed in the center of the inner water tube group,
The boiler according to any one of claims 1 to 3, wherein the burner is a mixed-burning burner. A boiler comprising a can having an inner water tube group and an outer water tube group arranged in an annular shape, and a burner disposed in the center of the inner water tube group,
Between the adjacent inner water pipes forming the inner water pipe group is closed except for a portion where a gas flow path is provided, and the gas flow path is annularly provided on one end side of the inner water pipe group,
The boiler according to any one of claims 1 to 3, wherein the burner is a mixed-burning burner. The boiler according to claim 5, wherein an enlarged heat transfer surface is provided on at least one of the inner water tube group and the outer water tube group in the vicinity of the gas flow path.

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