JP3726381B2 - Steam boiler - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention heats a heated fluid by catalytic combustion.Steam boilerIt is about.
[0002]
[Prior art]
With the recent increase in environmental problems, social demands for reducing air pollutant emissions from automobiles, industrial machinery, etc. have become more stringent, especially for NOx. Various measures for reducing air pollutants have been proposed, and one of them is the catalytic combustion method. This catalytic combustion method has an advantage that the combustion temperature can be lowered without increasing the CO generation amount and the NOx generation amount can be reduced by utilizing the catalyst surface reaction.
[0003]
In general, in a catalytic combustion apparatus, a mixed gas having a relatively high air ratio (about 2 to 4) is supplied. This is because the theoretical adiabatic flame temperature depends on the air ratio, and the lower the air ratio, the higher the flame temperature, and the catalyst burns all the fuel. This is because the heat resistance temperature of the catalyst is exceeded.
[0004]
Therefore, conventionally, the calorific value is small relative to the volume of the mixed gas to be supplied, and the improvement of the efficiency of the fluid heating device using such a catalytic combustion device, in other words, the achievement of downsizing has been hindered.
[0005]
Further, in such a catalytic combustion apparatus, the reaction flow path of the catalyst is short, so that unburned fuel components (CO, HC, etc.) may be discharged.
[0006]
[Problems to be solved by the invention]
The problem to be solved by the present invention is that combustion at a low air ratio is possible, no unburned portion is discharged, and high output is achieved.Steam boilerIs to provide. In other words, by controlling the reaction temperature (combustion temperature) at the catalyst part, even in the case of a mixed gas with a low air ratio, a stable combustion state is maintained by preventing burning and dissolution due to overheating of the catalyst. It is to achieve low CO of combustion exhaust gas.
[0007]
[Means for Solving the Problems]
This inventionA cylindrical partition wall and a cylindrical outer wall provided outside the partition wall, and formed in a fluid passage through which a fluid to be heated flows inside or between the partition wall and the outer wall; Forming between the outer walls or the inside of the partition wall in a gas passage through which a mixed gas of fuel and air flows, connecting a water supply pipe and a steam pipe to the fluid passage,In the gas passage 2, the above-described problems are solved by a configuration including a combustion heat transfer portion in which a catalyst portion and a heat transfer portion in contact with the partition wall are alternately arranged in the flow direction of the mixed gas. Is.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
The present invention relates to a fluid heating apparatus that heats a fluid to be heated by catalytic combustion. The fluid heating device as used in the present invention refers to the entire device for heating fluid such as a steam boiler, hot water boiler, hot air generator, etc., and includes those in which the fluid to be heated changes in phase, such as a steam boiler. It is out. Therefore, the fluid to be heated in the present invention refers to a liquid such as water or a gas such as air.
[0011]
In the catalytic combustion type fluid heating apparatus of the present invention, a fluid passage through which a fluid to be heated circulates and a gas passage through which a mixed gas of fuel and air circulates are partitioned by a partition, and a catalyst portion is provided in the gas passage. And the heat-transfer part made to contact with a partition is the structure provided with the combustion heat-transfer part formed by arrange | positioning alternately in the distribution direction of mixed gas. According to this configuration, the temperature of the mixed gas rises due to the catalytic reaction in the catalyst part, but immediately flows into the heat transfer part, and after heat exchange with the fluid to be heated and the partition wall, the temperature is lowered, It flows into the next catalyst part. By repeating this, the mixed gas having a low air ratio can be burned without overheating the catalyst portion.
[0012]
For this reason, in the present invention, the catalyst part constituting the combustion heat transfer part is configured to be at least shorter than the downstream catalyst part and set to have a low catalyst density, and each catalyst part in the combustion heat transfer part is The length, density, type of catalyst, and the like are set according to the oxygen concentration of the inflowing mixed gas and the fuel concentration so that the catalyst portion has a heat resistant temperature or lower. The density of the catalyst part is the area of the catalyst reaction surface per unit volume.
Here, in the first-stage catalyst portion on the most upstream side, a mixed gas having a low air ratio and high fuel concentration and oxygen concentration flows in, so that the temperature rapidly increases due to the catalytic reaction. Further, when the mixed gas flows into the next catalyst part, the fuel concentration and the oxygen concentration are reduced by combustion in the upstream catalyst part. Therefore, as described above, overheating of the catalyst portion is prevented by setting the length of the first-stage catalyst portion on the most upstream side short. Furthermore, as described above, the catalyst density per volume is increased in the downstream catalyst portion, or the catalyst portion is set longer in the flow direction of the mixed gas, so that a predetermined temperature is maintained. Further, in the heat transfer section, heat transfer from the mixed gas reacted in the previous catalyst section is performed to a temperature slightly higher than the catalyst activation temperature in the next catalyst section. Here, the catalyst activation temperature is a temperature at which the catalyst is activated to start a catalytic reaction and maintain this reaction.
[0013]
As described above, in the catalytic combustion type fluid heating apparatus according to the present invention, the temperature of the mixed gas is changed to the temperature of the catalyst unit by alternately repeating the temperature increase by the catalyst unit of each stage and the temperature decrease by the heat transfer unit. Control between the heat-resistant temperature and the temperature at which catalytic activity is exhibited.
[0014]
Furthermore, the catalytic combustion type fluid heating apparatus of the present invention has a configuration in which a gas processing unit including a catalyst unit is provided on the downstream side of the combustion heat transfer unit in the gas passage. Even if unburned fuel (hydrocarbon) or CO is generated in the combustion heat transfer section on the upstream side, the gas processing section is completely burned by the catalyst section of the gas processing section and prevents these emissions. . In short, the gas processing unit reacts the remaining fuel depending on how much the fuel in the mixed gas is reacted in the combustion heat transfer unit, and thereafter, the unburned fuel (hydrocarbon) and CO The length, density, type of catalyst, etc. of the catalyst part are set so as to prevent the discharge of etc. In this case, as will be described later, it is preferable to provide a heat recovery unit downstream of the gas processing unit and further recover the heat from the mixed gas from the gas processing unit.
[0015]
Furthermore, the catalytic combustion type fluid heating device of the present invention includes a heat recovery unit including a heat transfer member connected to the partition wall on the downstream side of the combustion heat transfer unit in the gas passage, and the catalyst unit. Alternatively, heat recovery is further performed from the combustion gas reacted in the gas processing section.
[0016]
Here, in the present invention, as described above, the catalyst parts and the heat transfer parts are alternately arranged, but the number of both is not necessarily the same. That is, the case where the catalyst part is arranged on the most upstream side and the most downstream side of the combustion heat transfer part is included. In this case, it is preferable to provide the above-described gas processing section and heat recovery section on the downstream side of the combustion heat transfer section.
[0017]
In each of the above catalyst parts, by interposing a heat insulating layer between the catalyst part and the partition wall, heat transfer in the catalyst part is prevented, and the catalyst reaction and the temperature increase due to this reaction can be easily controlled. This heat insulating layer is preferably composed of a general heat resistant heat insulating material such as ceramic or refractory mortar. The catalyst reaction surface is not formed on the peripheral surface of the catalyst portion facing the partition wall, and a gap is provided between the catalyst portion and the partition wall so that the catalyst portion and the partition wall are thermally blocked by this space. Good.
[0018]
Here, in the catalytic combustion type fluid heating apparatus of the present invention, each of the catalyst parts of the combustion heat transfer part and the gas processing part is composed of the catalyst itself, the catalyst is directly or directly on the member made of an appropriate material. Including those supported by a support layer. The catalyst used in this catalyst part is, for example, a noble metal such as Ag, Pt, Pd or the like having high low-temperature activity and a mixture of these with rare earth elements such as Ce, La, Y. A catalyst having low low-temperature activity such as composite oxide or SiC (silicon carbide) can also be used. Such a catalytic substance is supported on the surface of a structure such as a honeycomb shape or a pellet shape to form a catalytic reaction surface on the surface. At this time, the structure is made of alumina, silica, or a composite oxidation thereof. In the case of ceramic materials such as materials, it is directly supported on the surface, and when the structure is a metal material such as stainless steel, the surface is made of alumina, silica, or a composite oxide thereof. A catalyst carrier layer is formed and supported on the catalyst carrier layer. Here, the structure is preferably made of a material having high temperature durability such as a heat-resistant metal material such as stainless steel or a ceramic material such as SiN (silicon nitride) or cordierite.
[0019]
The catalyst part has a flow gap for flowing the mixed gas and contacting with the catalyst. The flow gap has a honeycomb shape having a large number of through holes such as a triangle, a quadrangle, a hexagon, and a circular cross section. In addition to the above-described ones, those formed by laminating corrugated sheets and flat plates having appropriate cross sections and those formed by arranging a large number of fin-like members are included. Here, the catalyst part in the combustion heat transfer part sets the area of the catalyst reaction surface and the amount and density of the supported catalyst so that the fuel in the mixed gas is completely combusted. When providing a part, it sets so that it may burn completely before leaving a gas processing part.
[0020]
In the catalytic combustion type fluid heating apparatus of the present invention, the heat transfer member constituting the heat transfer section and the heat recovery section performs heat transfer from the high-temperature mixed gas in the gas passage to the heated fluid via the partition wall. Therefore, it attaches at least with respect to a partition. This heat transfer member is a fin-shaped member, a honeycomb-shaped member as described above, or a member formed by laminating corrugated plates and flat plates.
[0021]
The heat recovery unit may be not only provided in a single stage in the gas passage, but also in a multi-stage arrangement in the gas passage in the flow direction of the mixed gas.
[0022]
Here, in this invention, the said partition is comprised as a heat exchanger tube which provided the fluid channel | path inside, for example, and the smoke tube which provided the gas channel | path inside. Furthermore, the fluid passage and the gas passage are not limited to one system as long as they are partitioned by a partition wall. For example, even if a plurality of sets of fluid passages and gas passages partitioned by partition walls are arranged, the partition walls may be configured in multiple cylinder shapes, and the gaps may be used as fluid passages and gas passages. . In the former case, each end of the plurality of fluid passages can be connected to a common flow path such as a header, and can be applied as a so-called multi-tubular fluid heating device. In the latter case, one passage alternately surrounds the other passage. Further, the flow direction of the mixed gas in the gas passage and the heated fluid in the fluid passage may be the same direction or the opposite direction. In particular, when a mixed gas with a low air ratio is burned, if the mixed gas and the fluid to be heated flow in the same direction, the mixed gas can be cooled by the cold fluid to be heated via the heat transfer member, so that the catalyst portion deteriorates The heat transfer member can be reduced in size.
[0023]
In this invention, mixed gas refers to the whole mixture of fuel and combustion air, and fuel includes not only gaseous fuel but also liquid fuel. In the case of gaseous fuel, it is supplied while being mixed with combustion air in a mixed gas previously mixed with combustion air or with a flow path upstream of the catalyst unit. In the case of the liquid fuel, the fuel vaporized or finely divided by a known means is handled in the same way as the gaseous fuel. In the present invention, in order to perform catalytic combustion, it is preferable that the fuel and the combustion air are mixed before reaching the catalytic reaction surface in the catalyst portion. Therefore, the gaseous fuel or the vaporized liquid fuel is mixed gas. It is preferable to supply in the form.
[0024]
【Example】
Hereinafter, a first embodiment in which the catalytic combustion type fluid heating apparatus according to the present invention is applied to a steam boiler will be described in detail with reference to FIGS. FIG. 1 is an explanatory diagram showing the configuration of the first embodiment of the catalytic combustion type fluid heating apparatus according to the present invention, and FIG. 2 shows the configuration example of the catalyst section in the catalytic combustion type fluid heating apparatus according to the present invention. FIG. 3 is an explanatory view showing a structural example of the heat transfer section in the catalytic combustion type fluid heating apparatus according to the present invention, and FIG. 4 shows the temperature change of the mixed gas in the catalytic fluid heating apparatus according to the present invention. FIG.
[0025]
The first embodiment shown in FIG. 1 is a specific example in which the catalytic combustion type fluid heating apparatus according to the present invention is a steam boiler, and the fluid to be heated is water. A partition wall 3 partitions a fluid passage 1 through which the fluid to be heated flows and a gas passage 2 through which a mixed gas of fuel and air and exhaust gas generated by combustion of the mixed gas circulate. The gas passage 2 in the first embodiment has a shape surrounding the fluid passage 1. That is, the partition wall 3 is configured as a heat transfer tube, water is supplied to the inside thereof, and a mixed gas is supplied to the outside for combustion. Further, the gas passage 2 is blocked from the outside by an outer wall 5. That is, the gas passage 2 is arranged so as to surround the outside of the fluid passage 1. Therefore, the fluid passage 1 and the gas passage 2 are partitioned by the partition wall 3, and the gas passage 2 is a space closed by the partition wall 3 and the outer wall 5.
[0026]
A water supply pipe 7 from a known water supply means (not shown) is connected to the upstream end (lower side in FIG. 1) of the fluid passage 1. On the other hand, a steam pipe 8 is connected to the downstream end (upper side in FIG. 1) of the fluid passage 1, and steam is supplied from the steam pipe 8 to a predetermined steam-using device.
[0027]
In the gas passage 2, there is provided a combustion heat transfer section 10 in which the catalyst section 11 and the heat transfer section 14 brought into contact with the partition wall 3 are alternately arranged in a plurality of stages in the mixed gas flow direction. It is. The flow direction of the mixed gas in the first embodiment is from the bottom to the top in FIG. 1, and is the same as the flow direction of the fluid to be heated. The catalyst unit 11 includes a large number of mixed gas flow gaps 18 (see FIG. 2), and a catalyst is supported on the wall surface of each flow gap 18.
[0028]
As shown in FIG. 2, the catalyst unit 11 in the first embodiment of the present invention has a configuration in which a corrugated plate-like member 16 and a flat belt-like member 17 are simultaneously wound in a spiral shape. The corrugated plate-like member 16 and the flat belt-like member 17 are configured to carry a catalyst. Of the catalyst units 11 constituting the combustion heat transfer unit 10, at least the first-stage catalyst unit 11 on the most upstream side is shorter than the other catalyst units 11 and the catalyst density is set low. This is because, on the most upstream side, a mixed gas having a low air ratio, high fuel concentration and high oxygen concentration flows in, and the temperature rapidly increases due to the catalytic reaction. Set the catalyst density low. Further, when the mixed gas flows into the next catalyst part, the concentrations of fuel and oxygen are reduced by combustion in the upstream catalyst part. Therefore, the length of the catalyst unit 11 is changed according to the oxygen concentration, the fuel concentration, and the temperature of the mixed gas flowing from the upstream side so that each catalyst unit 11 heated by the catalytic reaction of the mixed gas has a heat resistant temperature or less. The density, the type of catalyst, etc. are set. At this time, the catalyst density per volume of the downstream catalyst unit 11 is increased or the length of the catalyst unit 11 is set longer in the mixed gas flow direction. Thus, a predetermined temperature is maintained.
[0029]
On the other hand, the heat transfer section 14 flows in the high-temperature combustion gas from the catalyst section 11 and transfers heat held by the combustion gas to the fluid to be heated in the fluid flow path 1 through the partition wall 3. It is. The heat transfer section 14 transfers heat from the mixed gas reacted in the upstream (upstream side) catalyst section 11 to a temperature slightly higher than the catalyst activation temperature in the subsequent stage (rear stream side) catalyst section 11. Here, the catalyst activation temperature is a temperature at which the catalyst is activated to start a catalytic reaction and maintain this reaction.
[0030]
For example, as shown in FIG. 3, the heat transfer section 14 is configured by a large number of heat transfer fins 15 extending radially from the outer surface of the partition wall 3. In this first embodiment, the heat transfer portions 14 of each stage have the same arrangement pitch in the circumferential direction of the heat transfer fins 15 of the adjacent heat transfer portions 14 when viewed from the axial direction of the partition wall (heat transfer tube 3). And the heat transfer fin 15 of the other heat transfer section 14 is positioned between the heat transfer fins 15 of the one heat transfer section 14, and the temperature in the radial section of the catalyst section 11 on the downstream side The distribution is reduced.
[0031]
A gas processing unit 20 is provided on the downstream side of the combustion heat transfer unit 10 described above. In the illustrated embodiment, the gas processing unit 20 has three stages of catalyst units 21 having the same configuration as described above. The difference between the catalyst unit 21 in the gas processing unit 20 and the catalyst unit 11 of the combustion heat transfer unit 10 is set relatively long in the flow direction of the mixed gas in the gas passage 2 to increase the density of the catalyst. It is a point. That is, in the gas processing unit 20, the fuel in the mixed gas is consumed by the catalytic reaction in the upstream combustion heat transfer unit 10 and flows in as a mixed gas having a low oxygen concentration. Therefore, in the gas processing unit 20 as well, the catalyst surface 21 on the downstream side is made smaller in the equivalent diameter of the flow gap 18 to increase the catalyst surface area per unit volume, or the length of the mixed gas in the flow direction is set longer. For example, even a mixed gas with a low oxygen concentration can increase the calorific value and can be reliably burned.
[0032]
A heat recovery unit 30 having the same configuration as the heat transfer unit 14 in the combustion heat transfer unit 10 is provided on the downstream side of the gas processing unit 20.
[0033]
Now, the operation of the catalytic combustion type fluid heating apparatus having the above configuration will be described.
First, at least the catalyst unit 11 of the combustion heat transfer unit 10 is preheated by appropriate preheating means. As described above, this preheating means heats the catalyst part 11 itself, or heats it by supplying high-temperature air. Then, the supply of the mixed gas to the gas passage 2 is started in a state where the temperature at which the catalytic reaction can be started is reached. This mixed gas is considerably lower than an air ratio (about 2 to 5) of a mixed gas used in a general catalytic combustion apparatus, and an air ratio (1 to 1... Of a mixed gas used in a general flame combustion apparatus. About 5). In a conventional combustion apparatus that performs combustion only by a catalytic reaction without performing combustion by a flame, in order to avoid burning and melting of the catalyst, such a mixed gas having a low air ratio is not supplied.
[0034]
Since the catalyst unit 11 of the combustion heat transfer unit 10 has already been preheated and has been heated to a temperature at which catalytic combustion is possible, the combustion reaction starts immediately upon arrival of the mixed gas. The mixed gas is discharged as a high-temperature gas while passing through the catalyst unit 11 by catalytic combustion. After the catalytic combustion starts, the temperature of the catalyst part 11 and the high temperature gas from the catalyst part 11 rises. Further, in the combustion heat transfer section 10, the catalyst density per volume in the upstream catalyst section 11 is set so that the downstream catalyst density is small or the flow path length is set short. The mixed gas flows out from the catalyst unit 11 before reaching the heat resistant temperature of the catalyst 11. And the mixed gas which became high temperature by the catalytic reaction in this catalyst part 11 flows in into the heat-transfer part 14 of the next stage.
[0035]
In the heat transfer section 14, the heat of the high-temperature mixed gas is transferred to the heated fluid in the fluid passage 1 through the heat transfer fins 15 and the partition walls 3, so that the temperature of the mixed gas rapidly decreases. The temperature drop of the mixed gas due to heat transfer at this time is a temperature at which the catalytic reaction can be sufficiently started when the mixed gas flows into the next catalyst portion 11.
[0036]
And the mixed gas which flowed in the catalyst part 11 of the next stage starts a catalytic reaction immediately, and the temperature rises. Here, the mixed gas that has flowed into the catalyst unit 11 consumes fuel due to the catalytic reaction in the catalyst unit 11 on the upstream side, and the fuel concentration and the oxygen concentration are reduced. For this reason, the catalyst density per volume of the catalyst unit 11 is increased, or the flow path length is set long to continue the reaction, and the mixed gas temperature at the outlet of the catalyst unit 11 is kept high. This temperature is lower than the heat-resistant temperature of the catalyst part 11 as described above. And the mixed gas which became high temperature by the catalytic reaction in this catalyst part 11 flows in into the heat-transfer part 14 of the next stage further.
As described above, while repeating the catalytic reaction and heat transfer, the mixed gas is burned and the heated fluid is heated.
[0037]
Further, the mixed gas flowing out from the combustion heat transfer unit 10 flows into the gas processing unit 20. In the catalyst unit 21 of the gas processing unit 20, the residence time in the catalyst unit 21 is lengthened by setting the gas mixture in the flowing direction of the mixed gas to completely react the unburned portion. That is, most of the fuel reacts in the upstream catalyst section 11, and the amount of fuel in the mixed gas in the gas processing section 20 is very small. Further, in the gas processing unit 20, the catalyst density per volume is increased toward the downstream side, and the unburned portion is completely burned by this.
[0038]
Further, the mixed gas obtained by completely reacting the unburned portion in the gas processing unit 20 flows into the heat recovery unit 30 as high-temperature exhaust gas. This exhaust gas is heated by the catalytic reaction in the gas processing unit 20. The degree of the temperature rise is due to the reaction of the unburned portion in the gas processing unit 20, and thus the temperature rise is not as high as that of the combustion heat transfer unit 10, but the heat including the heat generated at this time is heated. The recovery unit 30 further performs heat transfer to the fluid to be heated. And the mixed gas which became low temperature by this heat transfer is discharged | emitted. Up to the gas processing unit 20, the heated fluid in the fluid passage 1 performs sufficient heat transfer and becomes steam.
[0039]
As described above, according to the catalytic combustion type fluid heating apparatus according to the present invention, in the combustion heat transfer section 10, the fuel in the mixed gas is reacted in multiple stages in an adiabatic state and disposed between the catalyst sections 11. By transferring heat to the object to be heated by the heat transfer section 14, even if the mixed gas has a low air ratio, excessive rise of the catalyst section 14 is suppressed, and stable combustion without causing burning or melting of the catalyst section 11. Heat transfer can be performed while performing. At this time, the mixed gas passes through the catalyst unit 11 and the heat transfer unit 14 alternately, thereby repeatedly raising the temperature and cooling. However, the mixed gas is controlled within a certain temperature range.
[0040]
Here, FIG. 4 is a diagram showing a change in the temperature of the mixed gas in the catalytic fluid heating apparatus according to the present invention. This diagram shows the case where the mixed gas having an air ratio of 1.2 and 1.1 is converted into a calorific value and supplied in an amount of 8.14 kw in the catalyst combustion type fluid heating apparatus having the above-described configuration. The length in the flow path direction is shown on the horizontal axis and the mixed gas temperature is shown on the vertical axis. In FIG. 4, the black squares on the horizontal axis are the arrangement ranges of the catalyst units 11 and 21, and the white squares on the horizontal axis are the installation ranges of the heat transfer units 14 and 31. As shown in FIG. 4, in the catalytic combustion type fluid heater of the present invention, even if a mixed gas with a low air ratio is supplied, the temperature of the catalyst part is all below the heat-resistant temperature of the catalyst, which is impossible in the past. The mixed gas having the same air ratio as that of the conventional combustion apparatus is stably burned without causing deterioration or burning of the catalyst.
[0041]
In the first embodiment, between the catalyst part 11 and the partition wall 3 and the outer wall 5 in the combustion heat transfer part 10, heat insulating layers 12 and 13 using appropriate heat insulating members such as ceramics are interposed, Further, heat insulating layers 22 and 23 are interposed between the catalyst unit 21 and the partition wall 3 and the outer wall 5 in the gas processing unit 20. As described above, by interposing the heat insulating layers 12, 13, 22, and 23 in the respective catalyst portions 11 and 21, heat radiation in each of the catalyst portions 11 and 21 is suppressed as much as possible so that heat is transferred only by combustion. This reaction state is stabilized by reacting the mixed gas in an adiabatic state. That is, the temperature change of the catalyst parts 11 and 21 due to heat transfer to the fluid to be heated is suppressed, and the catalytic reaction is stabilized as much as possible.
[0042]
Next, a second embodiment of the catalytic combustion type fluid heating apparatus according to the present invention will be described with reference to FIG. FIG. 5 is an explanatory diagram showing the configuration of the second embodiment of the catalytic combustion type fluid heating apparatus according to the present invention. In the second embodiment shown in the figure, the fluid passage 1 surrounds the outside of the gas passage 2. According to this configuration, all of the heat generated in the gas passage 2 is transferred to the heated fluid in the fluid passage 1 located outside the gas passage 2 except for the amount discharged together with the exhaust gas. Radiates less heat and improves thermal efficiency.
[0043]
Furthermore, in each embodiment of the present invention, the fluid passage 1 and the gas passage 2 are divided by the partition wall 3 so that one passage surrounds the other passage. In the present invention, the fluid passage 1 Alternatively, the gas passage may surround the outer periphery, and the fluid passage may surround the outer periphery.
Furthermore, the fluid heating device shown in each of the above embodiments is of a so-called monotube type using a single heat transfer tube, but a so-called multi-tube type in which a plurality of heat transfer tubes are connected at each end with a header. It is also possible to apply as a fluid heating device.
Further, the heat transfer section 14 and the heat recovery section 30 in each of the above embodiments are arranged with the heat transfer fins 15 and 31 shifted by a half pitch in the circumferential direction, but may be arranged at the same pitch. In this case, the heat transfer fins 31 in the heat recovery unit 30 can use long ones over the entire length of the heat recovery unit 30, and the number of parts and assembly man-hours can be reduced.
[0044]
【The invention's effect】
As described above, according to the steam boiler according to the present invention, the fluid passage through which the fluid to be heated flows and the gas passage through which the mixed gas of fuel and air flows are partitioned by the partition wall, The temperature of the mixed gas rises due to combustion in the catalyst unit by the configuration including the combustion heat transfer unit in which the catalyst unit and the heat transfer unit brought into contact with the partition wall are alternately arranged in the flow direction of the mixed gas. Since the gas passage is circulated while repeating the temperature drop due to heat transfer to the fluid to be heated in the heat transfer section, even if it is a mixed gas with a low air ratio, it does not cause burning or melting in the catalyst section. Stable steady combustion is possible.Further, since the fluid passage and the gas passage are formed in a double cylinder shape, a steam boiler with a simple configuration can be provided.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a configuration of a first embodiment of a catalytic combustion type fluid heating apparatus according to the present invention.
FIG. 2 is an explanatory diagram showing a configuration example of a catalyst unit in the catalytic combustion type fluid heating apparatus according to the present invention.
FIG. 3 is an explanatory view showing a configuration example of a heat transfer section in the catalytic combustion type fluid heating apparatus according to the present invention.
FIG. 4 is a diagram showing a change in the temperature of the mixed gas in the catalytic fluid heating apparatus according to the present invention.
FIG. 5 is an explanatory view showing a configuration of a second embodiment of the catalytic combustion type fluid heating apparatus according to the present invention.
[Explanation of symbols]
1 Fluid passage
2 Gas passage
3 Bulkhead
10 Combustion heat transfer section
11 Catalyst part
12 Insulation layer
14 Heat transfer section
15 Heat transfer fin (heat transfer member)
20 Exhaust gas treatment section
21 Catalyst part
30 Heat recovery unit
31 Heat transfer fin (heat transfer member)

Claims (1)

A tubular partition wall 3 and a cylindrical outer wall 5 provided outside the partition wall 3, and a fluid passage 1 through which a fluid to be heated flows inside the partition wall 3 or between the partition wall 3 and the outer wall 5. On the other hand, a gas passage 2 through which a mixed gas of fuel and air flows is formed between the partition wall 3 and the outer wall 5 or inside the partition wall 3, and a water supply pipe 7 and a steam pipe 8 are provided in the fluid path 1. And a combustion heat transfer section 10 in which the catalyst section 11 and the heat transfer section 14 brought into contact with the partition wall 3 are alternately arranged in the flow direction of the mixed gas. A featured steam boiler .

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