WO2014080657A1

WO2014080657A1 - Boiler device

Info

Publication number: WO2014080657A1
Application number: PCT/JP2013/066185
Authority: WO
Inventors: 孝明大西; 栄紀鈴木; 啓二西村
Original assignee: 三浦工業株式会社
Priority date: 2012-11-22
Filing date: 2013-06-12
Publication date: 2014-05-30
Also published as: JP6123253B2; JP2014105881A

Abstract

Provided is a boiler device which is configured so that, even if an air heater is provided in an air supply duct, the ratio of mixing between combustion air and a fuel gas can be maintained constant. A boiler device (1) is provided with: a can body (10); an air blower (20); an air supply duct (30); an air heater (70); a gas supply line (40); punched metal (314) provided at the part of the air supply duct (30), which is closer to the air blower (20) than the air heater (70), and reducing the pressure of air flowing through the air supply duct (30); a first pressure detection unit (315) for detecting the pressure upstream of the punched metal (314); a second pressure detection unit (316) for detecting the pressure downstream of the punched metal (314); and a control device (80) for controlling, on the basis of the difference between the pressure detected by the first pressure detection unit (315) and the pressure detected by the second pressure detection unit (316), the amount of a fuel gas supplied from the gas supply line (40).

Description

Boiler equipment

The present invention relates to a boiler device. This application claims priority based on Japanese Patent Application No. 2012-256900 for which it applied to Japan on November 22, 2012, and uses the content here.

Conventionally, boilers that generate steam by heating water with combustion gas generated by burning fuel gas in a can body are known. In the boiler, the fuel gas is mixed with combustion air and then supplied to the can body. The ratio (air / fuel ratio) at which the combustion air supplied to the can body and the fuel gas are mixed needs to be kept constant in order to stabilize the combustion state inside the can body.

As a device for controlling the amount of fuel gas to be supplied in accordance with fluctuations in the amount of combustion air supplied to the can body, a pressure reducing means is provided inside the air supply duct through which the combustion air flows. Has been proposed (see, for example, Patent Document 1), which controls the amount of fuel gas to be supplied based on the pressure difference (pressure loss) between before and after.

By the way, by providing an air heater that performs heat exchange between the combustion air mixed with the fuel gas and supplied to the can body and the combustion gas after being used to generate steam, heat is generated from the combustion gas. Boilers that have improved thermal efficiency by performing recovery have also been proposed.

In a boiler in which such an air heater is provided in an air supply duct, the technique described in Patent Document 1 is applied to control the amount of gas supplied based on the pressure loss of combustion air flowing through the air supply duct Even if the volumetric flow rate (m ³ / h) of combustion air is the same, the mass flow rate (kg / h) of combustion air increases as the temperature of combustion air decreases, so the fuel gas supplied This amount tends to be smaller than the amount of fuel gas required for combustion. Conversely, if the temperature of the combustion air increases, the mass flow rate decreases even if the volume flow rate of the combustion air is the same, so the amount of fuel gas supplied is the amount of fuel gas required for combustion Tend to be more.

JP-A-11-108352

In this way, an air heater (air heater) for heating combustion air is provided in the supply duct of the boiler, and further, a pressure reducing member is provided in the supply duct, and the difference in pressure before and after the pressure reducing means is determined. When the amount of gas to be supplied is controlled based on this, there is a high probability that the difference between the actually required gas amount and the supplied gas amount will increase. In particular, when the boiler is started, the temperature of the combustion air is low, so the amount of gas supplied tends to be smaller than the amount of gas required for ignition, and it is difficult to ignite the fuel gas. There has been a case where a problem occurs.

The present invention solves the above-described problem, and even when an air heater is provided in an air supply duct, a boiler device capable of maintaining a constant ratio of mixing combustion air and fuel gas. The purpose is to provide.

The present invention relates to a can body, a blower that supplies air to the can body, an air supply duct that connects the can body and the blower, and through which air supplied from the blower circulates, and the air supply duct. An air heater that heats the air supplied from the blower, and a gas supply line that is connected to the can body side of the air heater in the air supply duct and supplies fuel gas to the air supply duct; A pressure-reducing member that is disposed closer to the blower than the air heater in the air supply duct and depressurizes the air flowing through the air supply duct, and a first pressure detection unit that detects a pressure upstream of the pressure-reducing member. And a second pressure detector that detects a pressure downstream of the decompression member, and a difference between the pressure detected by the first pressure detector and the pressure detected by the second pressure detector, The gas supply line A control unit for controlling the supply amount of the fuel gas supplied from relates boiler apparatus comprising a.

The air supply duct further includes a damper that is disposed closer to the blower than the decompression member and adjusts the amount of air supplied from the blower, and the damper passes between the damper and the decompression member. It is preferable that the lengths are separated so as not to be affected by air drift.

According to the present invention, it is possible to provide a boiler device capable of maintaining a constant ratio of mixing combustion air and fuel gas even when an air heater is provided in an air supply duct.

BRIEF DESCRIPTION OF THE DRAWINGS It is an external view which shows the boiler apparatus which concerns on embodiment of this invention, FIG. 1 (a) is a front view of the said boiler apparatus, FIG.1 (b) is a right view of the said boiler apparatus, FIG. c) is a rear view of the boiler device, and FIG. 1D is a plan view of the boiler device. It is sectional drawing of the can part in the boiler apparatus which concerns on embodiment of this invention, and is a figure which shows the AA sectional view of FIG. (D). FIG. 3 is a sectional view taken along line BB in FIG. It is the schematic which shows the structure of the boiler apparatus which concerns on embodiment of this invention. It is the schematic shown about the shape of the air supply duct which connects an air blower and an air heater which looked at the boiler apparatus which concerns on embodiment of this invention from the left side surface.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the boiler apparatus 1 of the present embodiment has a can body 10, a blower 20 that feeds combustion air into the can body 10, and the combustion air flows through the connection between the can body 10 and the blower 20. An air supply duct 30, a gas supply line 40 (see FIG. 4) for supplying fuel gas to the air supply duct 30, an exhaust pipe 50 through which combustion gas discharged from the can body 10 circulates, and water in the can body 10 A water supply channel (not shown) to be supplied, an economizer 60 for exchanging heat between water supplied to the can 10 and the combustion gas, and an air heater for exchanging heat between the combustion gas and combustion air ( An air heater 70 according to the present invention and a control device 80 (see FIG. 4) for controlling a valve provided in the gas supply line 40 are provided.

As shown in FIGS. 2 and 3, the can body 10 includes a boiler housing 11, a plurality of water pipes 12, a connecting wall 13, a lower header 14, an upper header 15, and a burner 17.
The boiler housing | casing 11 comprises the external shape of the can 10, and is formed in the rectangular parallelepiped shape of planar view. An air supply port 18 is formed in the first side surface 11 a located on one end side in the longitudinal direction of the boiler housing 11, and a second side surface 11 b located on the other end side in the longitudinal direction of the boiler housing 11 is An exhaust port 19 is formed.
A front end portion of an air supply duct 30 described later is connected to the air supply port 18. The exhaust port 19 is connected to a base end portion of an exhaust cylinder 50 described later.

The plurality of water pipes 12 are disposed in the boiler casing 11 so as to extend in the vertical direction, and are disposed at predetermined intervals in the longitudinal direction and the width direction of the boiler casing 11.
In the present embodiment, the plurality of water pipes 12 are arranged along the longitudinal direction at the outer water pipe group 12 a arranged along the side part extending in the longitudinal direction of the boiler casing 11 and the center part in the width direction of the boiler casing 11. The central water pipe group 12b is disposed between the outer water pipe group 12a and the central water pipe group 12b.
The connection wall 13 connects the water pipes 12 arranged adjacent to each other in the outer water pipe group 12a.

The lower header 14 is formed of a rectangular parallelepiped container having a rectangular shape in plan view, and is disposed at the lower portion of the boiler casing 11. The lower header 14 is connected to lower ends of the plurality of water pipes 12. Water is supplied to the lower header 14, and water is supplied from the lower header 14 to the plurality of water pipes 12.

The upper header 15 is configured by a rectangular parallelepiped container having a rectangular shape in plan view, and is disposed on an upper portion of the boiler casing 11. The upper header 15 is connected to the upper ends of the plurality of water pipes 12. Steam generated in the plurality of water pipes 12 is collected in the upper header 15. The steam collected in the upper header 15 is led out to the outside through a steam outlet pipe 16 (see FIG. 1).
The burner 17 is disposed in the air supply port 18.

As shown in FIG. 1, the blower 20 is disposed at the lower part on the left side of the boiler device 1. The blower 20 has air wheel blades.
The air wheel blade is disposed inside the blower 20. As the air wheel blades rotate, the combustion air is drawn into the blower 20 and sent into an air supply duct 30 described later.

The air supply duct 30 has an upstream end connected to the blower 20 and a downstream end connected to the air supply port 18. The air supply duct 30 supplies the combustion air sent from the blower 20 to the can body 10.
As shown in FIG. 1, the air supply duct 30 includes an upward air supply passage portion 31, a first horizontal air supply passage portion 32, a first downward air supply passage portion 33, and a second horizontal air supply passage portion 34. And a second downward air supply passage 35.

As shown in FIG. 1C, the upward air supply passage portion 31 extends upward from a connection portion with the blower 20. More specifically, as shown in FIG. 5, the upward air supply passage portion 31 includes a first bent portion 311 and a second bent portion 312 provided on the blower 20 side. The upward air supply passage 31 is bent by the first bent portion 311 and the second bent portion 312 to such an extent that the combustion air fed from the blower 20 does not cause a drift.
A damper 313 is disposed in the vicinity of the first bent portion 311 in the upward air supply passage portion 31. By adjusting the opening degree of the damper 313, the circulation amount of the combustion air sent from the blower 20 is adjusted.

The 1st horizontal air supply path part 32 is connected to the upper end of the upward air supply path part 31, and is extended in a horizontal direction, as shown in FIG.1 (c) and (d).
The first downward air supply path section 33 extends downward from the tip of the first horizontal air supply path section 32 as shown in FIGS.

As shown in FIG. 1 (b), the second horizontal air supply passage portion 34 extends substantially horizontally from the front end portion of the first downward air supply passage portion 35 above the can body 10.
As shown in FIGS. 1A and 1B, the second downward air supply passage portion 35 extends downward from the distal end portion of the second horizontal air supply passage portion 34 along the first side surface 11 a of the can 10. It extends and is connected to the air inlet 18.

The gas supply line 40 is connected to the second downward air supply passage 35 and supplies fuel gas to the air supply duct 30. The gas supply line 40 is provided with a regulating valve 41, an orifice 42, and a plurality of nozzles 43.
The adjustment valve 41 adjusts the flow rate of the fuel gas supplied to the air supply duct 30. The orifice 42 is disposed on the downstream side of the adjustment valve 41.
The plurality of nozzles 43 are disposed at the distal end portion of the gas supply line 40 and jet fuel gas into the air supply duct 30. The tip ends of the plurality of nozzles 43 extend upward, that is, in a direction facing the flow direction of combustion air in the air supply duct 30 (see FIGS. 2 and 4).

According to the air supply duct 30 described above, the combustion air sent out from the blower 20 circulates upward in the upward air supply passage portion 31 as shown in FIG. 1 and then the first horizontal air supply passage portion. 32 circulates in the horizontal direction, then circulates downward in the first downward air supply passage portion 33, then circulates in the second horizontal air supply passage portion 34 in the horizontal direction, and finally the second downward air supply passageway. It is supplied to the can 10 by flowing downward through the portion 35. Further, in the second downward air supply passage 35, the fuel gas is supplied from the gas supply line 40, and the fuel gas and the combustion air are mixed.

The exhaust tube 50 is connected to the second side surface 11b of the can body 10 (boiler casing 11). The exhaust cylinder 50 discharges combustion gas generated by burning the mixed gas inside the can 10. The exhaust tube 50 has an upward exhaust passage portion 51 extending upward along the second side surface 11b.
According to the exhaust pipe 50 described above, the combustion gas discharged from the can body 10 is exhausted through the upward exhaust path portion 51 upward as shown in FIG.

The economizer 60 is disposed in the vicinity of the second side surface 11b of the can 10 (boiler casing 11). The economizer 60 exchanges heat between water flowing through a water supply channel (not shown) and combustion gas flowing through the exhaust pipe 50 (upward exhaust channel portion 51).
More specifically, the economizer 60 heats the water by exchanging heat between the water flowing through the water supply channel from above to the combustion gas flowing through the upward exhaust passage 51 upward from below.

As shown in FIG. 1, the air heater 70 is disposed in a portion where the first downward air supply passage portion 33 and the upward exhaust passage portion 51 are located above the economizer 60. The air heater 70 performs heat exchange between the combustion air flowing through the air supply duct 30 and the combustion gas flowing through the exhaust pipe 50 (upward exhaust passage portion 51).
More specifically, the air heater 70 exchanges heat between the combustion air that circulates in the first downward air supply passage portion 33 from below to the combustion gas that circulates in the upward exhaust passage portion 51 from below to above. By doing so, the combustion air is heated.

The control device 80 controls the amount of fuel gas supplied to the air supply duct 30 by controlling the opening degree of the regulating valve 41. The control device 80 includes a punching metal 314 as a decompression member disposed in the air supply duct 30, a first pressure detector 315 disposed on the upstream side of the punching metal 314, and a downstream side of the punching metal 314. The second pressure detection unit 316, the control unit 81, and the storage unit 82 are provided.

The punching metal 314 is configured by a metal plate in which a large number of through holes are formed. As shown in FIG. 5, the punching metal 314 is disposed on the upstream side of the air heater 70 and on the downstream side of the damper 313 in the upward air supply path portion 31. The punching metal 314 depressurizes the combustion air flowing through the upward air supply passage 31.
In the present embodiment, as shown in FIG. 4, the punching metal 314 and the damper 313 are separated by a length (L1) that is not affected by the drift of the air that has passed through the damper 313. ing. The length L1 between the punching metal 314 and the damper 313 is preferably 80 cm or more, more preferably 100 cm or more.

The first pressure detector 315 detects the pressure upstream of the punching metal 314. The second pressure detection unit 316 detects the pressure on the downstream side of the punching metal 314.

The storage unit 82 corresponds to the difference between the pressure upstream and downstream of the punching metal 314 detected by the first pressure detection unit 315 and the second pressure detection unit 316 in the boiler device 1 (pressure loss in the punching metal: ΔP). The supply flow rate (G) of the combustion gas supplied from the gas supply line 40 is stored. The relationship between ΔP and G is set so that the mixing ratio of the combustion air and the fuel gas is such that the mixed gas burns well inside the can 10. Usually, when ΔP increases, G also increases because more fuel gas is required, and when ΔP decreases, the amount of required fuel gas decreases and G also decreases.

The control unit 81 calculates the pressure loss (ΔP) in the punching metal 314 from the upstream and downstream pressures of the punching metal 314 detected by the first pressure detection unit 315 and the second pressure detection unit 316, and stores the pressure loss (ΔP) in the storage unit 82. The opening degree of the adjustment valve 41 is adjusted so that the stored G becomes G corresponding to the calculated ΔP.

Next, the operation of the boiler apparatus 1 will be described mainly with reference to FIG.

The boiler device 1 draws combustion air by the blower 20 and sends it out to the air supply duct 30. Since the air blower 20 is provided on the upstream side of the air heater 70, the air blower 20 can draw the combustion air before being increased in volume by being heated by the air heater 70 and send it to the air supply duct 30. Compared to the case where the blower 20 is provided on the downstream side of the air heater 70 by such an arrangement, the volume of the combustion air sent out by the blower 20 becomes relatively small, so that the power consumption by the blower 20 can be suppressed.
In the air supply duct 30, the combustion air sent out from the blower 20 circulates upward in the upward air supply path portion 31. The flow rate of the combustion air flowing through the upward air supply passage 31 is first adjusted by the damper 313. The combustion air whose flow rate is adjusted by the damper 313 is decompressed by the punching metal 314. The pressure on the upstream side of the punching metal 314 is detected by the first pressure detector 315, and the pressure on the downstream side of the punching metal 314 is detected by the second pressure detector 316, respectively.

The combustion air that has passed through the punching metal 314 flows through the first downward air supply passage 33 after passing through the upward air supply passage 31 and the first horizontal air supply passage 32.

The combustion air flowing through the first downward air supply passage 33 is heated by the air heater 70 by being exchanged with the combustion gas discharged from the can 10 and flowing through the exhaust tube 50.
The combustion gas discharged from the can body 10 circulates through a water supply channel in the economizer 60 and exchanges heat with water supplied to the can body 10 before heat exchange (second heat exchange) in the air heater 70. (First heat exchange).

Then, the combustion air after heat exchange with the combustion gas flowing through the air heater 70 flows through the second horizontal air supply passage 34 and then the second downward air supply passage 35. Circulate.

In the second downward air supply passage 35, the fuel gas is supplied through the gas supply line 40 and a plurality of nozzles 43 provided at the tip of the gas supply line 40, and the fuel gas and the combustion air are mixed.
The amount of combustion gas supplied is adjusted by the adjustment valve 41. The plurality of nozzles 43 extend in the direction opposite to the flow direction of the combustion air in the air supply duct 30, but in this way, the plurality of nozzles 43 correspond to the flow direction of the combustion air in the supply air duct 30. Therefore, the mixing property of the fuel gas and the combustion air is improved by being arranged in a direction inclined by 0 ° to 90 ° from the direction orthogonal to the flow direction.
The mixed gas is supplied into the can 10 through the air supply port 18.

In the can 10, the mixed gas is injected by the burner 17 and burned. By the combustion of the mixed gas, water (canned water) in the water pipe disposed inside the can body 10 supplied from the above-described water supply channel boils and generates steam. The steam generated in the water pipe is stored in the upper header 15 and then led out to the outside through the steam outlet pipe 16.

On the other hand, the combustion gas generated by the combustion of the mixed gas in the gas flow space is discharged from the exhaust port 19 to the exhaust pipe 50. The combustion gas discharged from the exhaust pipe 50 is discharged to the outside after being subjected to the first heat exchange and the second heat exchange described above (see FIG. 1).

The boiler device 1 according to the present embodiment has the following effects.
(1) In the boiler apparatus 1, in order to stabilize the combustion in the can 10, it is necessary to mix combustion air and fuel gas at an optimum ratio. This mixing ratio is based on the mass of the combustion air. It is required.
On the other hand, when the punching metal 314 is provided in the air supply duct 30 of the boiler device 1, the volume of combustion air is measured based on the pressure difference (pressure loss) between the upstream side and the downstream side of the punching metal 314. The flow rate (m ³ / h).
Normally, when the temperature of the combustion air is lowered, the volume of the combustion air is reduced, so that the mass flow rate (kg / h) of the combustion air is increased even if the volume flow rate of the combustion air is the same. Conversely, when the temperature of the combustion air increases, the volume of the combustion air increases, so that the mass flow rate decreases even if the volume flow rate of the combustion air is the same.
Accordingly, when the air heater 70 is provided in the air supply duct 30 of the boiler device 1 to heat the combustion air, and the amount of required fuel gas is calculated from the pressure loss of the combustion air flowing through the air supply duct 30, There is a high probability that a difference occurs between the calculated amount of fuel gas and the actually required amount of fuel gas.

In the boiler device 1 according to the present embodiment, the punching metal 314 is disposed closer to the blower 20 than the air heater 70 in the air supply duct 30. With such an arrangement, even if the combustion air is heated by the air heater 70, there is almost no temperature change of the combustion air in the vicinity of the punching metal 314, and the punching metal 314 is not considered even if the temperature change of the combustion air is taken into consideration. The ratio (mass ratio) for mixing the combustion air and the fuel gas based on the pressure loss before and after the above can be kept constant at all times. If the ratio of mixing the combustion air and the fuel gas can be kept constant, the combustion of the mixed gas inside the can 10 is stabilized.

(2) The boiler device 1 according to the present embodiment further includes a damper 313 that is disposed closer to the blower 20 than the punching metal 314 in the air supply duct 30 and adjusts the amount of air supplied from the blower 20. And the punching metal 314 are separated by a length that is not affected by the drift of the air that has passed through the damper 313.
With such an arrangement, the first pressure detection unit 315 and the second pressure detection unit 316 are not easily affected by the drift generated by the damper 313. Accordingly, it is possible to accurately measure the pressure loss before and after the punching metal 314, and it becomes easier to keep the ratio of mixing the combustion air and the fuel gas constant.

The preferred embodiment of the boiler device of the present invention has been described above, but the present invention is not limited to the above-described embodiment, and can be modified as appropriate.
For example, in the present embodiment, the upward air supply passage portion 31 includes the first bent portion 311 and the second bent portion 312, but is not limited thereto. That is, you may comprise an upward air supply path part linearly.

In this embodiment, the punching metal 314, the first pressure detection unit 315, and the second pressure detection unit 316 are arranged in the upward air supply path unit 31, but the present invention is not limited thereto. That is, the punching metal, the first pressure detection unit, and the second pressure detection unit may be arranged in other portions of the air supply duct as long as they are upstream of the air heater.

DESCRIPTION OF SYMBOLS 1 Boiler apparatus 10 Can body 20 Blower 30 Air supply duct 40 Gas supply line 70 Air heater (air heater)
80 Control device 313 Damper 314 Punching metal (decompression member)
315 First pressure detection unit 316 Second pressure detection unit

Claims

Can body,
A blower for supplying air to the can body;
An air supply duct that connects the can body and the blower, and through which air supplied from the blower flows,
An air heater provided in the air supply duct for heating air supplied from the blower;
A gas supply line connected to the can body side of the air heater in the air supply duct and supplying fuel gas to the air supply duct;
A pressure reducing member that is disposed closer to the blower than the air heater in the air supply duct, and depressurizes air flowing through the air supply duct;
A first pressure detector that detects a pressure upstream of the decompression member;
A second pressure detector for detecting the pressure downstream of the decompression member;
A control unit that controls a supply amount of the fuel gas supplied from the gas supply line based on a difference between the pressure detected by the first pressure detection unit and the pressure detected by the second pressure detection unit; A boiler device comprising:
It further includes a damper that is disposed closer to the blower than the decompression member in the air supply duct and adjusts the amount of air supplied from the blower.
The boiler device according to claim 1, wherein the damper and the pressure reducing member are separated by a length that is not affected by a drift of air that has passed through the damper.