JP3190939B2 - Steam generator - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steam generator, and more particularly to a steam generator suitable for reducing the temperature of a tube metal of a suspended heat transfer surface (superheater, reheater) and improving steam conditions. Related to the device.

[0002]

2. Description of the Related Art FIG.
FIG. 3 shows an example of a portion of a conventional suspended heat transfer surface structure (secondary reheater) of a boiler. In FIG. 2, high-temperature gas generated by combustion in the furnace 1 is cooled by a suspended heat transfer surface 4 suspended above the boiler, and then transferred to a horizontal heat transfer surface 5 where a lower-temperature fluid flows. And get out of the boiler after being cooled. FIG. 3 shows the configuration of the suspended heat transfer surface 4. The suspended heat transfer surface 4 is a ceiling wall tube 7 constituting a gas flow path.
And the bottom wall pipe 8, the upper part of which is arranged above the ceiling wall pipe 7 so as not to come into contact with the high-temperature gas, and the non-heating part pipes 21 and 22 connected thereto and the non-heating part pipes connected thereto. Heating unit tubes 23 and 24 arranged in a gas passage and heated by a high-temperature gas;
Non-heating portion pipes 25 and 26 are disposed outside the gas passages connecting the portions 3 and 24, respectively, and the outlet pipe 18 is connected to the non-heating portion tubes 25 and 26.

[0003] In the suspended heat transfer surface 4, the outer peripheral heating section tube 24 receives more radiant heat from the space than the heating section tube 23, and the length of the outer peripheral section heating section tube 24 is reduced. 23, the heat absorption amount in the outer peripheral portion heating tube 24 is larger than that in the heating portion tube 23. as a result,
The steam temperature of the outer peripheral portion heating tube 24 is higher than that of the heating portion tube 23. In addition, since the length of the outer heating section tube 24 is longer than that of the heating section tube 23, the pressure loss of the outer heating section tube 24 becomes relatively large, and the steam flow rate in the tube is reduced. The steam temperature of the section heating section tube 24 is more likely to rise.

In the structure of the conventional suspended heat transfer surface shown in FIG. 3, a method of adopting a tube material and a wall thickness that withstands the increased steam temperature is employed, or the inner diameter of the outer peripheral heating section tube 24 is increased. The method of increasing the steam flow rate is adopted. However, in the former method, when the quality of the pipe material is increased, the heat transfer coefficient is reduced, and when the pipe wall thickness is increased, the heat capacity is reduced. Not suitable. Further, in the latter method, the inner diameter of the heat transfer is different between the heating portion tube 23 and the outer peripheral portion heating portion tube 24, and the heat transfer area is increased in the outer peripheral portion heating portion tube 24 having the increased inner diameter. Because the heat absorption rate is high, the amount of heat absorption also increases significantly, and the effect of reducing the steam temperature rise due to the increase in the steam flow rate due to the increase in the inner diameter is halved, and at the same time the steam flow rate in the pipe is reduced, so the pipe cooling effect is also reduced There is a disadvantage that it decreases. In addition, the structure of the conventional suspended heat transfer surface shown in FIG. 3 is complicated, so that gas drift may occur, so that the steam condition for improving plant efficiency may be improved, or coal ash caused by gas drift may occur. The structure was not considered for a coal-fired boiler that caused erosion due to the above.

[0005]

The structure of the suspended heat transfer surface of the above-mentioned conventional boiler has a steam flow rate corresponding to the heat absorption amount,
No consideration was given to securing the steam flow rate, and there was a problem that the steam conditions for improving plant efficiency were improved or that the fuel was not suitable for a boiler using coal. Therefore, an object of the present invention is to suppress the imbalance in the amount of heat absorption between the outer peripheral heating unit tube of the suspended heat transfer surface and the inner peripheral heating unit tube inside the suspended heat transfer surface only to the difference between the tube length and the tube arrangement. That is.

[0006]

The above object of the present invention is achieved by the following constitution. That is, the inlet pipe arranged outside the high-temperature gas flow path and the outer peripheral non-heating part pipe and the inner peripheral part non-heating part pipe connected thereto, and further connected to the respective non-heating part pipes, The outer peripheral heating section tube and the inner peripheral section heating section pipe which are arranged in a row and heated by the high-temperature gas, and the outer peripheral section non-heating section pipe and the inner peripheral section which are respectively connected to the both heating section pipes and arranged outside the gas passage. In a steam generator having a suspended heat transfer surface composed of a non-heated portion pipe and an outlet pipe connected to the non-heated portion pipe, an outer peripheral portion of the suspended heat transfer surface having a relatively large heat absorption amount A steam generator in which the inner diameter of the outer peripheral non-heating section pipe connected to the heating section pipe is increased, and the internal diameter of the inner peripheral non-heating section pipe connected to the inner section heating section pipe, which has a relatively small heat absorption, is reduced. Or the inlet pipe located outside the hot gas flow path and the outer pipe connected to it Outer heating section pipe and inner heating section pipe, which are connected to the respective non-heating section pipes and are arranged in a gas passage and heated by a high-temperature gas. A pipe, an outer peripheral non-heating part pipe connected to the two heating part pipes and arranged outside the gas passage, an inner peripheral part non-heating part pipe, and an outlet pipe connected to the non-heating part pipe. In a steam generator with a suspended heat transfer surface, the length of the outer peripheral non-heating part pipe connected to the outer peripheral heating part pipe, which has a relatively large heat absorption, is relatively shortened, and the relative heat absorption is achieved. A steam generator with a relatively long inner peripheral non-heating part pipe connected to the inner peripheral heating part pipe with a small amount, or an inlet pipe located outside the high-temperature gas flow path and it The outer peripheral non-heating part pipe and the inner peripheral part non-heating part pipe to be connected, An outer peripheral heating section pipe and an inner peripheral section heating section pipe arranged in a gas passage and heated by a high-temperature gas; and an outer peripheral non-heating section pipe respectively connected to the heating section pipes and arranged outside the gas passage. In the steam generator having a suspended heat transfer surface composed of an inner peripheral portion non-heated portion pipe and an outlet pipe connected to the non-heated portion pipe, the relative heat absorption of the suspended heat transfer surface Increase the inner diameter of the outer peripheral non-heating part pipe connected to the outer peripheral heating part pipe with a large amount, and reduce the inner diameter of the inner peripheral non-heating part pipe connected to the inner peripheral heating part pipe with relatively small heat absorption And
Reducing the length of the outer peripheral non-heating part pipe connected to the outer peripheral heating part pipe with relatively large heat absorption, and connecting the inner peripheral heating part pipe with relatively small heat absorption to the inner heating part pipe This is a steam generator in which the length of the peripheral non-heating part tube is relatively long.

[0007]

The inner diameter of the outer peripheral non-heating part tube connected to the outer peripheral heating part pipe having a relatively large heat absorption is increased, while the inner peripheral heating part pipe having a relatively small heat absorption is connected to the inner peripheral heating part pipe. By reducing the inner diameter of the inner peripheral non-heating portion tube, the pressure loss of the steam flowing through the outer peripheral non-heating portion tube decreases, and the pressure loss of the steam flowing through the inner peripheral portion non-heating portion tube increases. As a result, a relatively large amount of steam can flow through the outer heating section tube than the inner heating section pipe.

In addition, the length of the outer peripheral non-heating part pipe connected to the outer peripheral heating part pipe having a relatively large heat absorption is relatively short, and the inner peripheral heating part having a relatively small heat absorption is relatively small. Reducing the pressure loss of the steam flowing through the outer heating section tube, which has a relatively large heat absorption, by increasing the length of the inner peripheral non-heating section pipe connected to the pipe, also reduces the outer heating section section. A relatively larger amount of steam can flow through the tube than the inner peripheral portion heating portion tube.

The above effect can be enhanced by adjusting the inner diameter of the pipe, adjusting the length of the pipe, or adjusting both of them. Further, since the inner diameter of the inner peripheral portion heating portion tube arranged in parallel with the outer peripheral portion heating portion tube does not need to be changed (can be the same), the imbalance of the heat absorption amount of each heat transfer tube can be reduced. The difference can be suppressed only by the arrangement of the pipe lengths, and no side effects such as an increase in heat absorption and a decrease in the steam flow velocity in the pipe do not occur. In this way, the steam temperature in each heat transfer tube can be made uniform, and the temperature of the tube metal of the outer peripheral portion heating portion tube can be reduced.

[0010]

An embodiment of the present invention will be described with reference to the drawings. Fig. 2 shows the overall structure of the boiler required for explaining the suspended heat transfer surface structure.
Will be described first. In FIG. 2, a high-temperature gas generated by combustion of fuel in a burner 2 on a wall of a furnace 1 is cooled by a suspended heat transfer surface 4 suspended above the boiler, and then flows through a lower-temperature fluid. The heat is further cooled by the horizontal heat transfer surface 5 and discharged from the boiler. An after-air port 3 for introducing air for complete combustion of fuel is provided on an upper wall surface of the wall surface on which the burner 2 is disposed.
Is provided. The suspended heat transfer surface 4 is suspended from the ceiling wall tube 7 and is disposed between the ceiling wall tube 7 and the bottom wall tube 8. The horizontal heat transfer surface 5 is disposed inside the rear heat transfer wall tube 6.

FIG. 1 shows a detailed view of the structure of the suspended heat transfer surface 4. The suspended heat transfer surface 4 is partitioned into a ceiling wall tube 7 and a bottom wall tube 8 that constitute a gas flow path, and the upper part of the ceiling wall tube 7 is arranged so as not to come into contact with high-temperature gas.
1 and the non-heating part pipes 12 and 13 connected thereto and the heating part pipes 14 and 15 and the heating part pipes 14 connected to the non-heating part pipes 12 and 13 and arranged in the gas passages and heated by the high-temperature gas, respectively. 15 and the non-heating part tubes 1 and 17 arranged outside the gas passage connecting the
6 and 17 are connected to an outlet pipe 18.

An outer peripheral non-heating tube 1 on the inlet side connected to an outer peripheral heating tube 15 located on the outer periphery of the inner peripheral heating tube 14.
3 or the inner diameter of the outer peripheral non-heating part pipe 17 on the outlet side is:
The inner diameter of the other inner peripheral non-heating part pipe 12 on the inlet side and the inner peripheral non-heating part pipe 16 on the outlet side are made larger than the inner diameter of the pipe. And
The inner diameters of the inner peripheral portion heating tube 14 and the outer peripheral portion heating portion tube 15 are the same. In addition, the inner peripheral non-heating portion tube 12 on the inlet side having a small inner diameter of the inner tube connected to the inlet tube portion 11 has an arrangement structure in which the tube is largely swung so as to increase its length.

The length of the outer peripheral portion heating section tube 15 is longer in terms of arrangement, and the heat transfer surface is correspondingly larger. At the same time, the outer peripheral heating section tube 15 faces the space disposed before and after the suspended heat transfer surface, and receives radiant heat therefrom, so that more heat is absorbed than the inner inner peripheral section heating section tube 14. Have received the quantity. The inner diameter of the outer peripheral non-heating part pipe 13 on the inlet side connected to the inlet and outlet of the outer peripheral heating part pipe 15 and the inner diameter of the outer peripheral non-heating part pipe 17 on the outlet side are defined as the outer peripheral non-heating part pipe 12 on the inlet side. The inner diameter of the non-heating part pipe 16 on the outlet side is larger than the inner diameter of the pipe, and the non-heating part pipe 13 on the inlet side is connected to the inlet pipe 11 with the shortest length. Is being reduced.

On the other hand, the inner diameters of the inlet-side inner peripheral portion non-heating portion tube 12 and the outlet side inner peripheral portion non-heating portion tube 16 connected to the inlet side inner peripheral portion heating portion tube 14 have outer diameters on the inlet side. The non-heating part tube 13 on the outlet side and the outer side non-heating part pipe 17 on the outlet side are smaller than those on the outlet side. It is designed so that the pressure loss of the steam flowing through the pipe is increased by increasing the length.

Due to these considerations, the pressure loss between the inlet pipe 11 and the outlet pipe 18 is substantially the same for each heat transfer pipe, and the outer peripheral section connected to the outer peripheral non-heating section pipe 13 on the inlet side with less pressure loss. The heating unit tube 15 has another inner peripheral heating unit tube 1.
More than four steams can flow. By utilizing this effect, the steam temperature in each heat transfer tube is made uniform by setting the steam flow rate in proportion to the heat absorption amount of the outer peripheral portion heating section tube 15, so that the tube metal temperature can be reduced.

Conventionally, a steam flow rate proportional to the amount of heat absorption could not be distributed except by changing the inner diameter of the heating section tube. The flow rate of steam flowing through the heat transfer tube can be changed by increasing the value of. According to such a configuration, side effects such as expansion of the heat absorption imbalance of the heat transfer tube and reduction of the steam flow velocity in the tube do not occur. Thus, it is possible to use a heat transfer tube made of a conventional material even in a boiler that improves steam conditions.

[0017]

According to the present invention, the flow rate of steam flowing through the heat transfer tube can be changed without increasing the heat absorption imbalance of the heat transfer tube, the pipe metal temperature can be greatly reduced, and the steam conditions can be improved. The current material can be used in the boiler to be used.

[Brief description of the drawings]

FIG. 1 is a view showing a suspended heat transfer surface structure according to an embodiment of the present invention.

FIG. 2 is a schematic diagram of the entire boiler and a diagram showing a place where a suspended heat transfer surface is arranged.

FIG. 3 is a diagram showing an example of a conventional suspended heat transfer surface structure.

[Explanation of symbols]

1 ... furnace, 4 ... suspended heat transfer surface, 11 ... near inlet pipe, 1
2, 16: inner peripheral non-heating part pipe, 13, 17: outer peripheral non-heating part pipe, 14: inner peripheral heating part pipe, 15: outer peripheral heating part pipe, 18: outlet pipe

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) F22B 1/18 F22B 37/10 F22B 37/12 F22G 3/00

Claims (4)

(57) [Claims] 1. A pipe connected to an inlet pipe located outside of a high-temperature gas flow path, an outer peripheral non-heater pipe connected to the inlet pipe, an inner peripheral non-heater pipe connected to the inlet pipe, and further connected to the respective non-heater pipes. An outer peripheral heating section pipe and an inner peripheral heating section pipe arranged in the gas passage and heated by the high-temperature gas, and an outer peripheral non-heating section pipe connected to both the heating section pipes and arranged outside the gas passage; In a steam generator having a suspended heat transfer surface composed of an inner peripheral portion non-heated portion pipe and an outlet pipe connected to the non-heated portion pipe, the heat absorption amount of the suspended heat transfer surface is relatively small. The inner diameter of the outer peripheral non-heating part pipe connected to the larger outer peripheral heating part pipe is increased, and the inner diameter of the inner peripheral non-heating part pipe connected to the inner peripheral heating part pipe with relatively small heat absorption is reduced. A steam generator characterized by the above-mentioned. 2. A pipe connected to an inlet pipe located outside the high-temperature gas flow path, an outer peripheral non-heater pipe connected to the inlet pipe, an inner peripheral non-heater pipe connected to the inlet pipe, and further connected to the respective non-heater pipes. An outer peripheral heating section pipe and an inner peripheral heating section pipe arranged in the gas passage and heated by the high-temperature gas, and an outer peripheral non-heating section pipe connected to both the heating section pipes and arranged outside the gas passage; In a steam generator having a suspended heat transfer surface composed of an inner peripheral non-heating part pipe and an outlet pipe connected to the non-heating part pipe, an outer peripheral heating part pipe having a relatively large heat absorption amount The length of the outer peripheral non-heating part tube connected to the inner peripheral part non-heating part pipe connected to the inner peripheral part heating part pipe with relatively small heat absorption is relatively reduced. A steam generator characterized by being lengthened. 3. A pipe connected to an inlet pipe located outside the high-temperature gas flow path, an outer peripheral non-heater pipe and an inner peripheral non-heater pipe connected thereto, and further connected to the respective non-heater pipes. An outer peripheral heating section pipe and an inner peripheral heating section pipe arranged in the gas passage and heated by the high-temperature gas, and an outer peripheral non-heating section pipe connected to both the heating section pipes and arranged outside the gas passage; In a steam generator having a suspended heat transfer surface composed of an inner peripheral portion non-heated portion pipe and an outlet pipe connected to the non-heated portion pipe, the heat absorption amount of the suspended heat transfer surface is relatively small. Increase the inner diameter of the outer peripheral non-heating part pipe connected to the larger outer peripheral heating part pipe, and reduce the inner diameter of the inner peripheral non-heating part pipe connected to the inner peripheral heating part pipe with relatively small heat absorption. The length of the outer peripheral non-heating part pipe connected to the outer peripheral heating part pipe with relatively large heat absorption Shortened, steam generator, characterized in that relatively long and the inside length of the peripheral portion unheated section tube that connects to the inner peripheral portion heating unit pipe less relatively heat absorption. 4. The steam generator according to claim 1, wherein the outer peripheral heating section tube and the inner peripheral section heating section tube have the same inner diameter.