JP2000028106A - Horizontal flue part - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a horizontal flue part solving such a disadvantage that a ratio of the combustion gas flow rate flowing through a gap having a small passage resistance increases compared with the combustion gas flowing through heat exchanger tubes and hence the heat transfer efficiency of the heat exchanging part of the horizontal flue part gets worse because the weir of the horizontal flue part is positioned at the opening to the inlet of the vertical flue part of the gap. SOLUTION: A weir 1 installed at the bottom face of a horizontal flue part 05 which allows the combustion gas 016 generated in a furnace to nearly horizontally pass through the inside of heat exchanger tubes of a plurality of heat exchangers 011, 012 extended down from the ceiling firnace wall 09 and the inside of a gap formed at the lower part of the heat exchangers 011, 012 and enter a vertical flue part, is erected from the bottom face of the further upstream side than the middle part of the heat exchangers 011, 012 adjacently extended down from the ceiling furnace wall 09 or the heat exchanger part 011 installed at the uppermost upstram side of the horizontal flue part 05.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a boiler or a horizontal section of a flue provided in a combustion furnace, and forms a lower end of a heat exchange section and a bottom of the flue which are suspended from above the flue. The high-temperature gas generated in the furnace may be short-passed from the gap formed between the top of the intermediate furnace wall and the convection heat transfer section of the heat exchange section installed in the flue may be generated in the heat transfer tube. The present invention relates to a horizontal flue portion provided with a weir for correcting gas temperature imbalance.

[0002]

2. Description of the Related Art A conventional boiler is shown in FIG.
As shown in FIG. 3, fuel 02 and air 03 are supplied from a nozzle provided through the furnace wall 01 below the boiler 010 to the inside of the furnace.
4 in the tangential direction of the swirling flow to be formed in the furnace 0
4. A swirling flow is generated to cause uniform combustion in step 4 and the combustion is performed to produce a combustion gas 01 of 1200 to 1400 ° C.
6 is generated. The combustion gas 016 generated in the furnace 04 passes through a horizontal portion 05 (hereinafter, referred to as a horizontal flue portion) of a flue provided above the boiler 010, and passes through the intermediate furnace wall 06 with the furnace 04. Equipped in the furnace 04
The air is discharged to the outside through a flue 09 connected to a chimney (not shown) via a vertical portion 07 (hereinafter, referred to as a vertical flue portion) of the flue provided in the opposite direction.

[0003] A furnace wall 01, a ceiling furnace wall 09, and an intermediate furnace wall 0 arranged before, after, and after forming the outer periphery of the boiler 010.
6, heat transfer tubes (not shown) are provided, and heat exchange is performed between feed water flowing through the heat transfer tubes and the combustion gas 016 to cool the furnace walls 01, 09, and 06. The furnace walls 01, 09, and 06 are protected from the high temperature of the combustion gas 016, and the feed water for generating steam is preheated to improve the thermal efficiency of the boiler 10.

[0004] Further, in the horizontal flue 05, heat exchanging parts 01 and 012 formed by heat transfer tube groups are provided with a ceiling wall 09.
, And the vertical flue portion 07 also has heat exchange portions 013 and 0
14 is provided so as to be supported by the rear furnace wall 01, the intermediate furnace wall 06, and the right and left furnace walls 01, and passes the combustion gas 016 through the horizontal flue portion 05 and the vertical flue portion 07, respectively. To perform heat exchange between a heated medium such as steam or feed water and a combustion gas 016 that are caused to flow through the heat transfer tubes forming the heat transfer tube group, and to perform a high-temperature, high-pressure I try to generate steam.

[0005] As described above, the combustion gas 016, which burns the fuel 02 and the air 03 and reaches 1200 to 1400 ° C in the furnace 04, reaches about 1200 ° C at the entrance of the horizontal flue section 05, and further, Heat exchange sections 011, 01 in the flue section 05
2 and about 800 ° C. at the entrance of the vertical flue 07 discharged from the horizontal flue 05
And the heat exchange sections 013, 0 in the vertical flue section 07
Similarly, a positive heat exchange is performed at 14, so that the flue 09 inlet discharged from the vertical flue section 07 has about 40
The temperature is lowered to 0 ° C, and the heat is recovered by an economizer (conserving device) provided in a flue 09 (not shown). The temperature is further reduced, and the temperature is supplied to a denitration and dedusting device to perform denitration and dedusting. After that, it is discharged from the chimney to the outside.

As described above, a heat transfer tube is provided upright, and a nose portion made of a refractory material is provided on the side of the furnace 04 above the intermediate furnace wall 06 which defines the furnace 04 and the vertical flue portion 07. 015
Is formed, the combustion gas 016 generated by swirling and burning in the furnace 04 has an appropriate flow passage area to the horizontal flue portion 05, and the combustion in the furnace 04 is performed stably. Thus, the temperature of the combustion gas 016 generated in the furnace 04 is prevented from being unbalanced.

FIG. 4 is a diagram showing an upper part of the boiler 010 as a model. As described above, the combustion gas 016 generated in the furnace 04 flows into the horizontal flue portion 05 through the flow passage whose flow passage area is regulated by the nose portion 015.
As described above, in the horizontal flue section 015, the heat exchange sections 011 and 012 formed by the heat transfer tube groups are provided so as to hang down from the ceiling wall 09, and the combustion flowing into the horizontal flue section 05 is provided. The gas 016 passes through the inside of the heat transfer tube group constituting the heat exchange units 011, 012, heats the medium to be heated in the heat transfer tubes, and connects the lower ends of the heat exchange units 011, 012 and the intermediate furnace wall. 06, between the heat exchange units 011, 0
In order to form a gap in consideration of elongation due to heating of 12, a part of the combustion gas 016 does not pass through the inside of the heat exchanger tube group, flows through this gap with a small flow path resistance at high speed, It may flow into the inlet of the vertical flue part 07.

That is, a part of the combustion gas 016 passes through the gap of the horizontal flue portion 015 without performing heat exchange with the medium to be heated flowing in the heat transfer tubes of the heat exchange portions 011, 012, and The combustion gas 016 as it is, the vertical flue 07
May flow into the entrance. As described above, in the gap formed between the lower end of the heat exchange section that is installed in the horizontal flue section 05 and hangs down in the horizontal flue section and the top of the intermediate furnace wall that forms the bottom of the horizontal flue section, Since a short path of the high-temperature combustion gas 016 generated in the furnace 016 occurs, the medium to be heated in the convection heat transfer unit heat transfer tubes of the heat exchange units 011, 012 is heated, and is inserted into the inlet of the vertical flue unit 07. Combustion gas inflow 01
6 may be unbalanced in temperature.

In particular, at a portion where the flow of the combustion gas 016 passing through the upper surface of the nose portion 015 passes through the gap in the horizontal flue portion 05 and flows into the inlet of the vertical flue portion 07, the gas further passes through the gap. Since the flow of the combustion gas 016 is accelerated, the local imbalance of the gas temperature for heating the heat transfer tube becomes remarkable, particularly in the heat exchange section 012 installed on the downstream side of the horizontal flue section 05.

For this reason, in the conventional boiler 10, as shown in the drawing, the height of the end of the horizontal flue portion 05, that is, the entrance of the vertical flue portion 07, is approximately twice the height of the gap. And a weir 017 perpendicular to the flow direction of the combustion gas 016
Is provided to solve this problem. Further, the provision of the weir 017 means that the high-temperature combustion gas 016 that has passed through the horizontal flue portion 05 at a high speed, hardly exchanges heat in the heat exchange portions 011, 012, and has reached the vertical flue portion 07. Of the vertical flue section 07, in particular, the heat exchange section provided in the vertical flue section 07, particularly, the heat transfer tube of the heat exchange section 013 provided near the entrance of the vertical flue section 07. It is also possible to avoid a local imbalance in the temperature of the gas for heating the heat transfer tube of the heat exchange unit 013 provided in the above.

However, in the above-described weir 017 provided at the end of the conventional horizontal flue section 05, particularly, the heat exchange section 0 whose heat exchange efficiency with the combustion gas 016 is deteriorated is reduced.
In 12, the flow of the high-temperature combustion gas 016 passing through the gap and flowing into the inlet of the vertical flue section 07 at high speed is deflected upward by the installation of the weir 017, and the heat exchange section 0
In order to heat the twelve heat transfer tubes, there is an advantage that the heat exchange efficiency is improved.
Because the flow of the combustion gas 016 on the upstream side is small,
It hardly contributes to the improvement of the heat exchange efficiency of the heat exchange unit 011, and the improvement of the heat exchange efficiency of the heat exchange unit 012 is also limited to the heating of the heat transfer tubes downstream of the heat exchange unit 012. However, there is a problem that it does not significantly contribute.

Further, as shown in FIG. 4, even if the combustion gas 016 in the high temperature state passing through the gap is splashed upward by the weir 017 and flows in above the inlet of the vertical flue portion 07, heat exchange is performed. No heat exchange section is provided above the vertical flue section 07 above the section 013, and no improvement in thermal efficiency can be expected due to the combustion gas 016 jumped up above this section. With respect to the heat exchange units 013 and 014 installed in the passage 07, the landing point of the flow is simply farther away, and in particular, the heat exchange unit 013 provided below the exit end of the horizontal flue 05 A large imbalance only occurs in the heating temperature of the heat transfer tube of the vertical heat transfer section 013, and only the heat transfer effect of the heat exchange section 013 is reduced.
However, the heat exchange units 013 and 014 installed in the have a problem that the heat transfer effect can hardly be expected.

[0013]

SUMMARY OF THE INVENTION The present invention relates to a boiler or a combustion furnace, which is installed in a horizontal flue section and which is short-circuited from a gap formed at the lower end of a heat exchange section which is hung down from the horizontal flue section. In order to eliminate the above-mentioned disadvantages of the conventional horizontal flue section, which prevents the heat transfer efficiency from being lowered by the passing combustion gas, the high-temperature combustion gas passing through the gap is raised upstream of the horizontal flue section. The horizontal flue, which could hardly be expected to improve the heat transfer efficiency with the installation of weirs so far, was able to reduce the short path of the combustion gas passing through the gap while maintaining the high temperature state. Can improve the heat transfer efficiency of the heat exchange section installed on the upstream side of the section, and further reduce the flow of combustion gas flowing into the inlet of the vertical flue section through the gap of the horizontal flue section To improve the heat transfer efficiency The heat transfer efficiency of the heat exchange section installed downstream of the flue section can be further improved, and the flow of high-temperature combustion gas reaching the vertical flue section is provided in the vertical flue section. It is possible to avoid directly hitting the heat exchange section, particularly, the heat exchange section of the heat exchange section provided near the entrance of the vertical flue section, and thereby the heat exchange section of the heat exchange section arranged in the vertical flue section is reduced. It is possible to avoid local unbalance of the temperature of the gas to be heated, and the landing point that flows in from the horizontal flue and collides with the heat transfer tube of the heat exchange section provided in the vertical flue becomes far away, An object of the present invention is to provide a horizontal flue portion that does not cause a local imbalance in the temperature of a gas to be heated.

Further, the present invention corrects the flow rate imbalance of the swirling flow of the combustion gas generated in the furnace in the furnace width direction, and makes the heat flow rate of the heat exchange section installed in the horizontal flue section uniform. It is an object to provide a horizontal flue section that can be designed.

[0015]

For this reason, the horizontal flue section of the present invention has the following means.

(1) The combustion gas generated in the furnace is substantially horizontal in the heat transfer tube group of the plurality of heat exchange sections provided by hanging from the ceiling furnace wall and in the gap formed below the heat exchange section. A weir installed on the bottom of the horizontal flue section, which is to be introduced into the vertical flue section, adjacent to the middle part of the heat exchange section provided hanging from the ceiling furnace wall, or horizontal The heat exchanging section was installed on the most upstream side of the flue section, and was set up from the bottom of the horizontal flue section on the upstream side.

Preferably, the weir is made of a heat-resistant steel plate and its height is about twice as large as a gap formed below the heat exchange part. In addition, the horizontal flue section does not refer to the flue in which the combustion gas flows horizontally in a strict sense, but refers to the flue where the horizontal component of the flow of the combustion gas becomes large.

(A) Thus, in the horizontal flue section of the present invention, as in the case of the conventional weir installed at the most downstream side of the horizontal flue section, the heat exchange provided by hanging from the ceiling furnace wall. Through the gap formed in the horizontal flue below the pipe, the heat recovery in the heat exchanger is reduced, and to the heat exchanger tubes of the heat exchanger in the vertical flue of hot combustion gases. In addition to avoiding direct hits and avoiding local imbalance of the combustion gas that heats the heat transfer tubes, in addition to the high temperature combustion that flows from the inlet side of the horizontal flue and passes through the gap Combustion that passes through the gap while maintaining high temperature by increasing the flow rate of combustion gas flowing inside the heat exchanger tube group of the heat exchange section by blowing gas upward on the upstream side of the horizontal flue section The short path of gas is reduced, Improvement of heat transfer efficiency can not be throat expected N 殆, it is possible to improve the heat transfer efficiency of the heat exchange portion so as to installed upstream of horizontal smoke path unit.

Furthermore, the flow of the combustion gas flowing into the inlet of the vertical flue section through the gap of the horizontal flue section is reduced, and the combustion gas is installed on the downstream side of the horizontal flue section to improve the heat transfer efficiency. As for the heat transfer efficiency of the heat exchange section, the amount of heat transfer not only on the downstream side of the heat exchange section but also on the upstream side of the heat exchange section is improved by the combustion gas jumped from the gap. Thermal efficiency can be further improved.

Further, by providing a conventional weir at the entrance of the vertical flue portion in the gap, the combustion gas flowing from the horizontal flue portion and colliding with the heat transfer tube of the heat exchange portion provided in the vertical flue portion is provided. It is also possible to prevent the landing point from becoming distant, and accordingly, it is possible to reduce the local imbalance of the gas temperature for heating the heat transfer tubes in the heat exchange unit installed in the vertical flue.

Further, the horizontal flue section of the present invention is characterized in that (1)
In addition to the above means, the following means were adopted. (2) The weir provided in the horizontal flue section is installed by changing the height in the width direction of the horizontal flue section, that is, the direction perpendicular to the direction of the flow of the combustion gas.

The height of the horizontal flue of the weir in the width direction is
At the center in the width direction of the horizontal flue section, the height is changed from about twice the height of the gap formed below the heat exchange section to about the height of the gap. Is preferred.

(B) Thus, in the horizontal flue section of the present invention, in addition to the above (a), the height of the weir provided in the horizontal flue section in the width direction of the horizontal flue section is different, so that the furnace The swirl flow of combustion gas generated inside the furnace can be corrected to the flow width imbalance in the furnace width direction flowing out to the horizontal flue section, and the heat flow rate of the heat exchange section installed in the furnace width direction of the horizontal flue section Can be made uniform.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a horizontal flue section dam according to the present invention will be described below with reference to the drawings. In the drawings, the same or similar members as those shown in FIGS. 3 and 4 are denoted by the same reference numerals, and description thereof will be omitted as much as possible. FIG. 1 is a view showing a first embodiment of the horizontal flue section of the present invention.

As shown in the figure, in the horizontal flue section of the present embodiment, the heat exchanging sections 011 and 01 composed of a group of heat transfer tubes suspended from the ceiling furnace wall 09 in the horizontal flue section 05.
The weir 1 erected from the bottom of the horizontal flue section 05 is provided adjacent to the heat exchange sections 011 and 0 so as to be orthogonal to the flow of the combustion gas 016 flowing in the gap formed below the lower section 2.
12 are provided in the furnace width direction.

By installing the weir 1, a gap formed between the lower end of the heat exchange section 011 provided on the upstream side and the upper surface of the nose section 015 formed of a refractory material on the upper end of the intermediate furnace wall 06. The high-temperature combustion gas 016 passing through is heated upward from a position in front of the heat exchange unit 012 provided downstream of the weir 1. The high-temperature combustion gas 016 jumped upward by the weir 1 heats the heat transfer tubes on the rear end side forming the heat transfer tube group of the upstream heat exchange unit 011 to heat the downstream heat exchange unit 012. After passing through the heat transfer tube group, heat exchange is performed with steam or feed water inside the heat transfer tubes forming the heat transfer tube group, and the temperature of the heat transfer tube is reduced to flow downstream.

A part of the combustion gas 016 that has passed through the heat exchanger tube groups of the heat exchange units 01 1 and 012 is
Flows through the gap formed below the gap, but compared to the case where the weir 017 is provided at the most downstream portion of the conventional gap,
The combustion gas 016 passing through the gap passes through the heat transfer tube group of the heat exchange unit 012, performs heat exchange with the heat transfer tube of the heat exchange unit 012, and then flows into the gap. And the combustion gas 0 flowing into the inlet of the vertical flue section 07
A low-temperature gas equivalent to the temperature to 16 and the vertical flue 07
You will reach the entrance.

As described above, according to the horizontal flue section weir of the present embodiment, in addition to the effect obtained when the weir 017 is provided at the most downstream of the conventional gap, the horizontal flue section 05 The heat exchange section 0 that flows in from the inlet side and is provided in the horizontal flue section
The high-temperature combustion gas passing through the gap formed below 11,012 is splashed upward on the upstream side of the horizontal flue section 05 and passes through the inside of the heat transfer tube group of the heat exchange sections 011,012. The flow rate of the flowing combustion gas 016 increases, the short path of the combustion gas 016 passing through the gap in a high temperature state can be reduced, and the installation of the conventional weir 017 hardly improves the heat transfer efficiency. The heat transfer efficiency of the heat exchange unit 011 arranged upstream of the unit 05 can be improved.

Further, it is possible to prevent the landing point of the combustion gas 016 flowing from the horizontal flue portion 05 from colliding with the heat transfer tube of the heat exchange portion 13 provided in the vertical flue portion 07. Heat exchange unit 0 installed in vertical flue 07
The local imbalance of the gas temperature for heating the thirteen heat transfer tubes can also be reduced.

Next, FIG. 2 is a view showing a second embodiment of the horizontal flue section dam of the present invention. As shown in the figure, in the horizontal flue section weir of the present embodiment, similarly to the horizontal flue section weir of the first embodiment, the transmission suspended from the ceiling furnace wall 09 in the horizontal flue section 05 is shown. Heat exchange unit 011, consisting of a heater tube group
Combustion gas 01 flowing in a gap formed below 012
The weir 2 is provided upright from the bottom of the horizontal flue section 05 in the furnace width direction between the adjacent heat exchange sections 011 and 012 so as to be orthogonal to the flow of 6.

Further, the height of the weir is changed in the furnace width direction as shown in FIG. 2 (b). That is, a terrace is formed at the center in the furnace width direction so that the height on the right furnace wall 01 'side is about twice as high as the height on the left furnace wall 01 "side. .

As described above, weir 2 provided in horizontal flue section 05
Is changed in the furnace width direction to pass through a gap formed between the lower part of the heat exchange part 011 and the upper surface of the nose part 015, similarly to the weir 1 in the first embodiment described above. The high-temperature combustion gas 016 is jumped upward by the weir 2 provided on the upstream side of the heat exchange unit 012 provided on the downstream side, and the high-temperature combustion gas 016 thus jumped up is separated from the heat exchange units 011, 012. As a result, the heat transfer efficiency increases, the temperature of the combustion gas 016 decreases, flows downstream, and reaches a vertical flue portion 07 as a low-temperature gas as compared with the conventional case. The same operation and effect as those of the first embodiment can be obtained.

Further, in the horizontal flue section weir of the present embodiment, the height of the weir 2 is changed in the furnace width direction, so that the weir is provided through the furnace wall 01 below the boiler 010. In parallel with the control of the inflow direction of the fuel 02 and the air 03 from the nozzles so as to form a swirling flow, as shown in FIG. Thus, the in-furnace swirling flow 3 that swirls in a substantially perfect circular state can be generated, and the generation of the in-furnace swirling flow 3 corrects the flow imbalance of the combustion gas 016 that may have occurred in the furnace width direction. The heat exchange units 011, 012, 0
13 can make the heat flux uniform,
The heat transfer efficiency of the heat exchange units 011, 012, and 013 can be further improved.

In the above-described embodiment, each of the weirs 1 and 2 is provided between the heat exchanging unit 011 and the heat exchanging unit 012, which are both suspended from the horizontal flue 05. Although the upright portion is provided from the bottom of the passage portion 05, the present invention is not limited to such an embodiment, and the horizontal flue portion 05 such as the upper surface of the nose portion 015 on the upstream side of the heat exchange portion 11 is provided. However, it can also be provided on the more upstream side.

[0035]

As described above, in the horizontal flue section of the present invention, a weir to be installed on the bottom of the horizontal flue section is adjacently suspended from the ceiling furnace wall of the horizontal flue section. In the middle part of the provided heat exchange part, or the heat exchange part which is installed on the most upstream side of the horizontal flue part, it is set up from the bottom of the horizontal flue part further upstream and installed. did.

Thus, the high-temperature combustion gas flowing from the inlet side of the horizontal flue section and passing through the gap is splashed upward at the upstream side of the horizontal flue section, so that the inside of the heat exchange section heat transfer tube group is formed. By increasing the flow rate of the combustion gas flowing through the gap, it is possible to reduce the short path of the combustion gas passing through the gap while maintaining the high temperature state, and to improve the heat transfer efficiency of the heat exchange section installed on the upstream side of the horizontal flue section. As well as being able to improve, the heat transfer efficiency of the heat exchange section, which is arranged on the downstream side of the horizontal flue section, also improves the heat transfer amount of almost all the heat transfer tubes by the combustion gas jumped up from the gap, The heat transfer efficiency of the heat exchange section can be improved, and the heat transfer efficiency of the boiler can be improved.

Further, the combustion gas flowing from the horizontal flue section can be prevented from arriving at a distant point of collision with the heat transfer tube of the heat exchange section provided in the vertical flue section. In the heat exchange section installed in the road, the local imbalance of the gas temperature for heating the heat transfer tubes can be reduced,
From this point as well, the heat transfer efficiency of the boiler can be improved.

Further, the horizontal flue section of the present invention is installed with its height changed in the width direction of the horizontal flue section. As described above, by changing the height of the weir in the width direction of the horizontal flue section, it is possible to correct the flow rate imbalance in the furnace width direction of the swirling flow of the combustion gas generated in the furnace, and thereby to improve the horizontal flue. It is possible to make the heat flow rate of the heat exchange unit installed in the unit uniform.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of a horizontal flue section of the present invention,

FIG. 2 is a view showing a second embodiment of the horizontal flue section of the present invention, wherein FIG. 2 (a) is a cross-sectional view, and FIG. 2 (b) is a view taken along the line AA shown in FIG. 2 (a). 2 (c) is a front view of FIG.
FIG. 3A is a plan view taken along the line BB shown in FIG.

FIG. 3 is an overall cross-sectional view of a conventional boiler,

FIG. 4 is a cross-sectional view showing a model of an upper portion of the boiler shown in FIG.

[Explanation of symbols]

 01 Furnace wall 02 Fuel 03 Air 04 Inside the furnace 05 Horizontal flue section 06 Intermediate furnace wall 07 Vertical flue section 08 Flue stack 09 Ceiling furnace wall 010 Boiler 011,012 Horizontal flue section heat exchange section 013,014 Vertical flue section Heat exchange part 015 Nose part 016 Combustion gas 017 Weir 1 Weir 2 Weir 3 Swirling flow 10 Boiler 10 'Boiler

Claims (2)

[Claims] A combustion gas generated in a furnace is substantially horizontal in a heat transfer tube group of a plurality of heat exchange units provided by hanging from a ceiling furnace wall and in a gap formed below the heat exchange unit. In the horizontal flue section where the weir is installed in the gap where the weir is introduced into the vertical flue section, the weir is located in the middle of the heat exchange section adjacent to A horizontal flue section, which is installed on the bottom surface on the upstream side of the heat exchange section installed on the upstream side. 2. The horizontal smoke according to claim 1, wherein the weir is installed with a height changed in a width direction of the horizontal flue portion orthogonal to a direction of the flow of the combustion gas. Dobu.