JPH08327007A - Supercritical variable pressure once-through boiler - Google Patents

Abstract

PURPOSE: To eliminate the life consumption of a furnace pressure resistant part by vertically dividing a furnace peripheral wall, providing lower and upper furnace peripheral wall tube outlet and inlet headers, and providing a mixer connected to the headers. CONSTITUTION: Combustion gas generated at the lower part of a furnace 14 is lifted while being heat absorbed, and fed from the upper part of the furnace to a rear flue 12. The peripheral wall of the furnace 14 is vertically divided at the intermediate part of its height, and the lower furnace peripheral wall tube outlet header 21 connected to the outlet of the heat transfer tube 16 for forming the lower furnace peripheral wall, the upper furnace peripheral wall inlet header 17 connected to the inlet of the heat transfer tube 15 for forming the upper furnace peripheral wall and the mixer 19 connected to the headers 21, 17 are provided. Even if the fluid of the tube 16 is irregular and the part has the degree of superheat, it is completely agitated and mixed by the mixer 19, and the fluid of uniform enthalpy level is distributed at the inlet of the tube 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a furnace system configuration of a supercritical pressure transformer once-through boiler for electric power industries and other industries.

[0002]

2. Description of the Related Art FIG. 20 is a system diagram showing an example of the configuration of a conventional supercritical pressure transformer once-through boiler. In this figure,
The feed water exiting the economizer (not shown) arranged in the rear flue (12) passes through the furnace inlet connecting pipe (1) to the furnace peripheral wall evaporation pipe inlet pipe drawer (4) at the lower part of the furnace (14). When entering, the furnace peripheral wall evaporation pipe (2) forming the furnace peripheral wall arranged almost vertically is heated and rises to reach the uppermost part of the furnace. Then, it flows into the steam-water separator (7) from the furnace peripheral wall evaporating pipe outlet header (5) through the furnace outlet connecting pipe (6), and is separated into steam and drain in the operation in the subcritical pressure region. . The steam separated by the steam separator (7) flows to the superheater (9) via the superheater inlet communication pipe (13). On the other hand, the drain separated in the steam separator (7) is returned to the inlet of the economizer by the circulation pump (11) via the drain discharge pipe (8). In this case, as a matter of course, the drain level adjusting valve (10) is controlled so that the drain level in the steam separator (7) does not fall below a certain level.

As a design consideration for the furnace peripheral wall evaporator tube (2) of the conventional boiler having such a system, it may be a once-through type, and the enthalpy level of the furnace outlet fluid is the static characteristics of the furnace shown in FIG. As shown in the data, it is set higher than the saturation temperature in the subcritical pressure region, but it is designed so that its superheat degree is as small as possible due to the reason described in the next section.

[0004]

In the conventional boiler as described above, there is a problem that a temperature imbalance occurs between the tube groups at the outlet of the furnace peripheral wall evaporation tube. This is because when there is a deviation in the amount of heat absorption in the wall surface due to the combustion condition in the furnace, this appears as an imbalance in the outlet fluid temperature of each evaporation tube. If an imbalance occurs in the metal temperature of the peripheral wall of the furnace, there is a risk of damage to the pressure-resistant part of the furnace due to the associated thermal stress. Therefore, early establishment of a countermeasure to prevent this temperature imbalance is urgently required.

As a design consideration for this, it is first considered that an orifice or the like is provided at the inlet of each evaporation pipe and the amount of water supplied is adjusted according to the heat absorption deviation to suppress the imbalance of the outlet fluid temperature. However, it is difficult to eliminate the temperature imbalance by this method because the deviation of the heat absorption amount and the water supply distribution characteristics change depending on the boiler load.

Therefore, as a fundamental method for eliminating this temperature imbalance, it is conceivable to design the furnace by setting the fluid enthalpy level at the outlet of the furnace peripheral wall evaporator tube to a wet state. Then, even if there is a slight difference in the amount of heat absorption between a and b of the static characteristic data of the furnace shown in FIG. 19 mentioned above, that is, even if an imbalance of the fluid enthalpy occurs, the temperature of the fluid remains saturated at the saturation temperature. Since it becomes constant, it does not appear as a temperature difference.

However, since the size of the furnace is determined as the space required for complete combustion of the fuel, it is not possible to make the furnace smaller than that and reduce the heat transfer area of the peripheral wall of the furnace. Therefore, there is an example in which the fluid enthalpy level at the outlet of the furnace peripheral wall evaporation pipe is designed to be wet by adding it to the boiler water system at the outlet of the furnace peripheral wall and further providing a heat transfer surface that functions as an evaporator on the downstream side. It was FIG. 21 is a diagram showing the furnace characteristics of such a conventional case. However, in this case, even if the static characteristic is wet, as shown in the figure, the dynamic characteristic shows a characteristic that there is a hysteresis between "load increase" and "load decrease" due to the heat storage capacity of the metal. . Especially in the case of "load reduction", a large degree of superheat may occur as shown in the figure. Further, FIG. 22 shows a case of a boiler in which the heat transfer surface composed of the evaporator is not provided in the rear flue unlike the case of FIG. 21.

Further, in order to deal with the above-mentioned temperature imbalance problem between the tube groups at the outlet of the furnace peripheral wall evaporation tube, the superheat is already generated in the middle portion of the furnace peripheral wall evaporation tube, although it is in a dynamic state at the time of partial load. Paying attention to the fact that there is a tube having the above, as shown in FIG. 23, a furnace peripheral wall intermediate pipe header (22) is provided at a position of the intermediate height of the furnace peripheral wall, and the two-phase fluid of the lower furnace peripheral wall evaporation pipe is supplied to this intermediate pipe. There is also an example in which the system is introduced into the gather (22), mixed, and then flowed to the upper furnace peripheral wall evaporation pipe. However, the effect of reducing the imbalance of the fluid temperature at the upper furnace outlet is still insufficient.
This is because the precondition of the interfacial method is that there is an outlet to the upper furnace peripheral wall evaporation pipe at the interface level of the two phases of steam and water in the intermediate header (22), so that the fluid conditions in the intermediate part are made uniform. This is due to the fact that it is not always satisfied due to the level difference in the longitudinal direction of the inner interface of the pipe, pulsation, etc., and the difference in fluid conditions (dryness, etc.) between adjacent tubes is made uniform to some extent. You can do that, but Fig. 24
When a dry region is generated over a wide range as described above, it does not function as a means for reducing the temperature imbalance. Therefore, the mixing method in the middle portion cannot completely solve the problem of temperature imbalance, and further improvement is needed.

When a temperature imbalance occurs due to an increase in the degree of superheat as described above, a large thermal stress is generated in the wall surface of the furnace. Therefore, the thermal resistance of the furnace consumes its life due to the repeated thermal stress caused by the load change. As a result, damage may hinder the operation of the boiler.

[0010]

In order to solve the above-mentioned conventional problems, the present inventor proposes the following supercritical pressure transformer once-through boiler.

[1] A furnace having a peripheral wall formed of a heat transfer tube and a burner for injecting fuel and combustion air into the lower part of the furnace for combustion are provided, and combustion gas generated in the furnace is formed on the peripheral wall of the furnace. In a supercritical pressure variable pressure once-through boiler that rises while absorbing heat and flows from the upper part of the furnace to the rear flue, the furnace peripheral wall is divided into upper and lower parts, and it is connected to the outlet of the heat transfer tube forming the lower furnace peripheral wall. Lower furnace peripheral wall pipe outlet header, upper furnace peripheral wall pipe inlet header connected to the inlet of the heat transfer tube that constitutes the upper furnace peripheral wall, the lower furnace peripheral wall pipe outlet header and the upper furnace peripheral wall pipe inlet header And a mixer connected to the supercritical pressure transformer once-through boiler.

[2] A furnace having a peripheral wall composed of heat transfer tubes and a burner for injecting fuel and combustion air into the lower part of the furnace for combustion are provided, and combustion gas generated in the furnace is formed on the peripheral wall of the furnace. In a supercritical pressure transformer once-through boiler that rises while absorbing heat and flows from the upper part of the furnace to the rear flue, the furnace peripheral wall is divided into upper and lower parts, and the outlet of the heat transfer tube that constitutes the lower furnace peripheral wall and the upper furnace A supercritical pressure transformer once-through boiler, which is provided with a header having a partition wall which is connected to both an inlet of a heat transfer tube which constitutes a peripheral wall and which is twisted by 180 ° in the center of a cross section.

[3] A furnace having a peripheral wall composed of a heat transfer tube, and a burner for injecting and burning fuel and combustion air into the lower part of the furnace, and combustion gas generated in the furnace is formed on the peripheral wall of the furnace. In the supercritical pressure transformer once-through boiler that rises while absorbing heat and flows from the upper part of the furnace to the rear flue, the peripheral wall of the furnace is divided into upper and lower parts, and a partition is divided into two chambers by a longitudinal partition wall. The outlet of the heat transfer tube which is provided for each wall surface of the furnace peripheral wall and which constitutes the lower left half portion of each wall surface is provided in one of the chambers, and the heat transfer tube which constitutes the lower right half portion of each wall surface is The outlet is connected to the other side of the room, and the inlet of the heat transfer tube that constitutes the upper right half of each of the wall surfaces is further connected to the one side of the room, of the heat transfer tube that constitutes the upper left half of the wall surface. The entrance to the other of the above rooms, A supercritical pressure transformer once-through boiler characterized by being connected to each other.

[4] A furnace having a peripheral wall formed of a heat transfer tube and a burner for injecting fuel and combustion air into the lower part of the furnace for combustion are provided, and combustion gas generated in the furnace is formed on the peripheral wall of the furnace. In the supercritical pressure transformer once-through boiler that rises while absorbing heat and flows from the upper part of the furnace to the rear flue, the peripheral wall of the furnace is divided into upper and lower parts, and a partition is divided into two chambers by a longitudinal partition wall. The outlet of the heat transfer tube provided on each wall surface of the furnace peripheral wall and forming the lower left and right corners of each wall surface is provided in one of the chambers, and the outlet of the heat transfer tube forming the lower center portion of each wall surface To the other side of the room, respectively, further the inlet of the heat transfer tube constituting the upper central portion of the wall surface to the one of the room,
A supercritical pressure variable pressure once-through boiler, wherein inlets of heat transfer tubes constituting upper left and right corners of each wall surface are respectively connected to the other of the chambers.

[5] A furnace having a peripheral wall composed of a heat transfer tube and a burner for injecting fuel and combustion air into the lower part of the furnace for combustion are provided, and combustion gas generated in the furnace is formed on the peripheral wall of the furnace. In a supercritical pressure transformer once-through boiler that rises while absorbing heat and flows from the upper part of the furnace to the rear flue, the peripheral wall of the furnace is divided into upper and lower parts, and a set of two pipes are attached to each wall surface of the peripheral wall of the furnace. And the outlet of the heat transfer tube that constitutes the lower left half of each wall is
The outlet of the heat transfer tube that constitutes the lower right half of each wall surface is connected to one of the pair of headers and is connected to the other of the headers, and the upper right half of each wall surface is further configured. The inlet of the heat transfer tube to the one of the above-mentioned tube drawers, the inlet of the heat transfer tube that constitutes the upper left half of each wall surface to the other of the above tube drawers,
A supercritical pressure transformer once-through boiler characterized by being connected to each other.

[6] A furnace having a peripheral wall composed of a heat transfer tube, and a burner for injecting fuel and combustion air into the lower part of the furnace for combustion are provided, and combustion gas generated in the furnace is formed on the peripheral wall of the furnace. In a supercritical pressure transformer once-through boiler that rises while absorbing heat and flows from the upper part of the furnace to the rear flue, the peripheral wall of the furnace is divided into upper and lower parts, and a set of two pipes are attached to each wall surface of the peripheral wall of the furnace. And the outlet of the heat transfer tube that constitutes the lower left and right corners of each wall surface is provided on one side of the pair of two pipes, and the outlet of the heat transfer tube that constitutes the lower center part of each wall surface is described above. The inlet of the heat transfer tube, which is connected to the other of the headers and which constitutes the upper central portion of each wall surface, is provided with the inlet of the heat transfer tube, which constitutes the upper left and right corners of each wall surface, at the one of the headers. Connected to the other side of the heading A supercritical pressure variable pressure once-through boiler.

[0017]

In the solution means [1], the peripheral wall of the furnace is divided into upper and lower parts, and the outlet wall of the lower peripheral wall of the furnace, which is connected to the outlet of the heat transfer tube forming the lower peripheral wall of the furnace, and the upper peripheral wall of the furnace. Since the upper furnace peripheral wall pipe inlet header connected to the inlet of the heat transfer pipe constituting the, and the mixer connected to the lower furnace peripheral wall pipe outlet header and the upper furnace peripheral wall pipe inlet header All the boiler water that has exited from the furnace peripheral wall heat transfer tube on the side flows through the mixer to the furnace peripheral wall heat transfer tube on the upper side. Therefore, even if there is variation in the fluid in the lower furnace peripheral wall heat transfer tube, and in some cases there is some superheat, it is completely agitated and mixed by the mixer, and at the inlet of the upper furnace peripheral wall heat transfer tube. A uniform enthalpy level of fluid is dispensed. As a result, the temperature difference between the heat transfer tube groups at the upper furnace peripheral wall heat transfer tube outlet is greatly reduced, and the furnace wall metal temperature imbalance remains in the safe area even in a transient state. The life of the pressure-resistant part of the furnace due to repeated thermal stress is not consumed, and further damage to the boiler furnace wall due to fatigue is prevented.

Next, in the above-mentioned solving means [2] to [6], the peripheral wall of the furnace is divided into upper and lower parts, and the outlets of the heat transfer tubes forming the lower peripheral wall of the furnace and the heat transfer tubes forming the upper peripheral wall of the furnace are formed. Or a pipe head connected to both the inlet and having a partition wall twisted 180 ° in the center of the cross section,
Alternatively, the furnace peripheral wall is divided into upper and lower parts, and a pipe partitioning into two chambers by longitudinal partition walls is provided for each wall surface of the furnace peripheral wall, and the lower left half part of each wall surface is formed. The outlet of the heat pipe is connected to one of the rooms, the outlet of the heat transfer tube forming the lower right half of each wall is connected to the other of the room, and the transfer forming the upper right half of each wall is connected. The inlet of the heat tube is connected to the one side of the room, the inlet of the heat transfer tube forming the upper left half of each wall is connected to the other side of the room, or the lower left and right corners of each wall are connected. The outlet of the heat transfer tube that constitutes the above is connected to one of the chambers, the outlet of the heat transfer tube that configures the lower central portion of each of the wall surfaces is connected to the other of the chamber, and the upper central portion of each of the wall surfaces is configured. Set the inlet of the heat transfer tube to the above one side of the above room and The inlet of the heat transfer tube that constitutes the upper left and right corners is connected to the other of the above-mentioned chambers respectively, or the furnace peripheral wall is divided into upper and lower parts, and two pairs of pipes are attached to each wall surface of the furnace peripheral wall. The outlet of the heat transfer tube that is provided and constitutes the lower left half of each wall surface is provided to one of the pair of pipes, and the outlet of the heat transfer tube that constitutes the lower right half of each wall is described above. The inlet of the heat transfer tube, which is connected to the other of the headers and further constitutes the upper right half of each wall surface, is provided with the inlet of the heat transfer tube, which constitutes the upper left half of each wall surface, to the one of the headers. Is connected to the other of the headers, or the outlet of the heat transfer tube that constitutes the lower left and right corners of each of the wall surfaces is connected to one of the pair of headers and the lower side of each wall surface. The outlet of the heat transfer tube that constitutes the central portion is connected to the other of the above-mentioned tube drawers, respectively, Note: The inlet of the heat transfer tube that constitutes the upper center portion of each wall surface is connected to the one side of the above-mentioned header, and the inlet of the heat transfer tube that constitutes the upper left and right corners of each wall surface is connected to the other one of the above header. Therefore, the fluid in the furnace peripheral wall heat transfer tube on the lower side moves in the header provided at the intermediate height of the furnace and flows to the furnace peripheral wall heat transfer tube at another position on the upper side. And the mixing of the fluids is promoted during the movement. Therefore, even if a dry region is formed over a considerable width of the central portion of each wall of the furnace peripheral wall during partial load, load drop, or subcritical pressure, as shown in FIG. The fluid around the corners and the fluid in the dry area are sufficiently mixed.

[0019]

FIG. 1 is a system diagram showing a supercritical pressure transformer once-through boiler according to a first embodiment of the present invention, and FIG. 2 is a system diagram showing in detail a furnace peripheral wall intermediate pipe header of the supercritical pressure transformer once-through boiler. ,
Fig. 3 is a horizontal sectional view (section III-III in Fig. 4) showing the intermediate part of the furnace peripheral wall, Fig. 4 is a vertical sectional side view taken along line IV-IV in Fig. 3, and Fig. 5 is a rear view taken along the line V-V in Fig. 3. 6 and 6 are partial detailed views of the intermediate portion of the intermediate wall of the furnace wall, and FIG. 7 is VII- of FIG.
FIG. 7 is a side view taken along the arrow VII.

First, as shown in FIG. 1, in the boiler of this embodiment, a peripheral wall is constituted by a heat transfer tube, and a furnace (14) which stands almost vertically, and fuel and combustion air are introduced into the lower part thereof. Combustion equipment consisting of burners, air jets, etc. for combustion is provided so that combustion gas generated in the lower part of the furnace (14) rises while being absorbed by the peripheral wall of the furnace and flows from the upper part of the furnace to the rear flue (12). Has become. In this embodiment, the peripheral wall of the furnace (14) is divided into upper and lower parts at the middle part of its height,
Lower furnace peripheral wall pipe outlet header (21) connected to the outlet of the lower furnace peripheral wall (16) and upper part connected to the inlet of the upper furnace peripheral wall (15) A furnace peripheral wall tube inlet header (17), a lower furnace peripheral wall tube outlet header (21) and a mixer (19) connected to the upper furnace peripheral wall tube inlet header (17) are provided.

Speaking of the water supply and steam system, from the outlet of the economizer (not shown) installed in the rear flue (12), through the furnace inlet connecting pipe (1), the lower furnace peripheral wall pipe inlet pipe (2)
The feed water that entered 0) enters the lower furnace peripheral wall heat transfer tube (16) and rises while absorbing heat from the combustion gas in the furnace (14), and is installed in the middle part of the height of the furnace (14). It goes out to the peripheral wall pipe outlet pipe header (21). As shown in FIG. 2, the lower furnace peripheral wall tube outlet header (21) is connected to the furnace (1
4) It is a square ring-shaped structure that surrounds
The mixer (19) is fixed by directly connecting its inlet. Two of them are arranged near the corners on the left and right of the front wall, and two are similarly arranged on the rear wall side. Since the lower furnace peripheral wall pipe outlet pipe header (21) is ring-shaped, both ends of (21) in FIG. 2 are connected. The two-phase fluid that has been sufficiently stirred and mixed by the mixer (19) flows through the connecting pipe to the inlet (17) of the upper furnace peripheral wall pipe on average. In the illustrated example, the upper furnace peripheral wall pipe inlet pipe header (17) is divided into four parts corresponding to the four wall faces.

Returning to FIG. 1, the fluid that has entered the upper furnace peripheral wall pipe inlet pipe inlet (17) into the upper furnace peripheral wall heat transfer pipe (15) is reheated in the upper part of the furnace, and the upper furnace peripheral wall pipe outlet outlet (18) is reheated. Go to. Then, it flows into the steam separator (7) through the furnace outlet communication pipe (6), and is separated into steam and drain there. The steam separated by the steam separator (7) is guided to the superheater (9) through the superheater inlet communication pipe (13). On the other hand, the drain separated by the steam separator (7) is returned to the inlet of the economizer by the circulation pump (11) via the drain discharge pipe (8). In this case, of course, the drain level adjusting valve (10) is controlled so that the drain liquid level in the steam separator (7) does not fall below a certain level.

Next, a concrete structure of the furnace intermediate pipe pulling portion will be described with reference to FIGS. In side view, the furnace (1
4) In the middle part of the height, a lower furnace peripheral wall tube outlet outlet (21) is provided so as to surround the furnace (14), and a total of four mixers (19) are provided on the left and right front walls and the left and right rear walls. It can be seen in plan view that is connected directly to this header (21) in the longitudinal direction. Then, the steam-water two-phase boiler water mixed in the mixer (19) was divided into four parts by the connecting pipe, including the front and rear walls and the side wall.
7) You will enter. There are a total of 48 connecting pipes that fit this heading, one quarter of which is 12
They are connected by a connecting pipe of a book, and the pipe arrangement between the mixers (19) is almost the same.

In this embodiment, the lower furnace peripheral wall tube outlet header (21) has a square ring-shaped single structure, and the upper furnace peripheral wall tube inlet header (17) has four walls corresponding to the four wall surfaces. It is divided. However, these headers (17),
In all of (21), the peripheral wall heat transfer tubes in charge are the total number of furnace peripheral walls independently, or the number of peripheral wall heat transfer tubes obtained by dividing the peripheral wall, or the number of peripheral wall heat transfer tubes surrounding the peripheral wall of the furnace. It may be installed as a single header or a plurality of headers facing a single or a plurality of wall surfaces of the peripheral wall.

Next, FIG. 8 is a plan view showing a furnace peripheral wall intermediate pipe pulling portion in the second embodiment of the present invention, and FIG. 9 is IX-IX of FIG.
It is an arrow crossing side view. In the present embodiment, a furnace peripheral wall intermediate pipe (22) provided with a partition wall (25) along the longitudinal direction at the center of the cross section at the middle height portion of the vertical furnace is provided with respect to the four peripheral wall surfaces of the furnace (14). Provide each. The partition wall (25) is twisted 180 ° at a key point. Then, the lower furnace peripheral wall heat transfer tube (1
6) and the upper furnace peripheral wall heat transfer tube (15) are both connected. At that time, each furnace peripheral wall intermediate pipe header (22) connects the lower left half side of the peripheral wall heat transfer tube of each wall surface to the upper right half side, and conversely connects the lower right half side to the upper left half side, It is possible to form two streams separated by a partition wall (25) in the header. That is, as shown in FIG. 9, the fluid in the lower furnace peripheral wall heat transfer tube (16) in the right half part horizontally flows into the furnace peripheral wall intermediate tube header (22) from the left side, and the intermediate tube header (22). After moving inside, the partition wall (25) was twisted 180 ° at the middle part on the left and right and passed through the place where it was installed. Then, from the position shifted in the width direction of the furnace, move horizontally to the right and to the left. It flows into the upper furnace peripheral wall heat transfer tube (15) in the half part.

Although not shown in the drawing, when the parts in the width direction of the furnace for mixing are the left and right corners and the central part, the partition wall (2
There are two 180 ° twists in 5), and the positions are provided at the boundary between both corners and the central part, and from the left and right ends of the header to about ¼ of the header length.

Next, FIG. 10 is a plan view showing a furnace peripheral wall intermediate pipe pulling portion in a third embodiment of the present invention, and FIG. 11 is a plan view of FIG.
XI-XI arrow cross-sectional side view, FIG. 12 is a XII-XII arrow cross-sectional side view of FIG. The difference of this embodiment from the second embodiment is that the partition wall (26) in the header is flat and not twisted. Therefore, the fluid coming from the lower furnace peripheral wall heat transfer tube (16) moves to the furnace peripheral wall intermediate pipe (2
It is the same as flowing through 2) to the upper furnace peripheral wall heat transfer tube (15) and moving laterally in the header to mix the fluid, but the left half XI-XI cross section (Fig. 11) and right Half of XII-XI
In the I section (Fig. 12), the entrance and exit of the peripheral wall heat transfer tubes are opposite. Although not illustrated, as in the case of the second embodiment, there may be cases where the parts in the width direction of the furnace where they are mixed are the left and right corner parts and the central part.

Next, FIG. 13 is a plan view showing a furnace peripheral wall intermediate pipe pulling portion in a fourth embodiment of the present invention, and FIG. 14 is a plan view of FIG.
XIV-XIV arrow cross-sectional side view, FIG. 15 is a XV-XV arrow cross-sectional side view of FIG. As in the case of the second and third embodiments, the configuration of the fourth embodiment includes a lower furnace peripheral wall heat transfer tube (16) and an upper furnace peripheral wall heat transfer tube (15) at an intermediate height position of a vertical furnace. The same is the point that the furnace peripheral wall intermediate pipe headers connected to both are provided correspondingly to the four peripheral wall faces of the furnace (14), but the pipe divider partition walls (25) and (26) are not used, but instead. Two furnace peripheral wall intermediate pipes for each wall
The difference is that it is configured using (22a) and (22b). In other words, the two fluid flows in the opposite directions are moved to the partition wall (2
5), (26) instead of two furnace peripheral wall intermediate pipe (2
This is realized by using 2a) and (22b). One direction is the left half side of the lower furnace peripheral wall heat transfer tube (16) to the right half side of the upper furnace peripheral wall heat transfer tube (15), and the other direction is the reverse half of the lower furnace peripheral wall heat transfer tube (16). Is connected to the left half side of the upper furnace peripheral wall heat transfer tube (15), and the left and right fluids are mixed during lateral movement within the header of the tube.

Next, FIG. 16 is a plan view showing a furnace peripheral wall intermediate pipe pulling portion in a fifth embodiment of the present invention, and FIG. 17 is a plan view of FIG.
XVII-XVII arrow cross-sectional side view, FIG. 18 is XVIII- of FIG.
It is a cross-sectional side view taken along the arrow XVIII. In the above-described fourth embodiment, the mixing portion in the furnace width direction that receives from the lower furnace peripheral wall heat transfer tube (16) and distributes to the upper furnace peripheral wall heat transfer tube (15) is such that the lower left half side is the upper right half side. While the lower right half side was connected to the upper left half side, respectively, in the fifth embodiment, the lower furnace peripheral wall heat transfer tube (16)
The tubes on both corner sides (both left and right corners) of the upper furnace peripheral wall heat transfer tube (15) are opposite to the lower furnace peripheral wall heat transfer tube (1
6) is different in that the central pipe is connected to both corner side pipes of the upper furnace peripheral wall heat transfer pipe (15).

The operation and effect peculiar to each embodiment having the above-mentioned structure will be described below.

First, the first embodiment will be described. The point that the furnace heat transfer tube heat transfer tube is divided into two parts at the intermediate height part of the two-phase flow region and a pipe offset is provided is the conventional method described in FIG. In the present embodiment, the lower furnace peripheral wall pipe outlet pipe outlet (21) and the upper furnace peripheral wall pipe inlet pipe inlet (17) are provided, and four mixers (19) are provided between them. Then, all the fluids which come out from the heat transfer tubes of the lower furnace peripheral wall and which have a superheat degree in some cases and have variations are always passed through one of the mixers (19) to be completely stirred and mixed. As a result, the fluid condition of the boiler water becomes uniform at the inlet of the upper furnace peripheral wall heat transfer tube (15).
The temperature difference between the heat transfer tube groups at the outlet of the upper furnace peripheral wall heat transfer tube (15) is significantly reduced, and the furnace wall metal temperature imbalance remains in a safe region even in a transient case. In this way, it is possible to eliminate the lifetime consumption of the furnace pressure-resistant portion due to the repeated thermal stress caused by the load change, and to prevent damage accidents of the boiler furnace wall due to fatigue.

Next, in the second to fifth embodiments, when the load is dropped by partial load and the pressure is subcritical pressure, as shown in FIG. 24, a considerable amount of the central portion of each wall surface of the furnace peripheral wall is provided. Paying attention to the fact that a dry region is generated over the width and that the left and right corners and their surroundings remain at the saturation temperature even at such a time, a header is provided at the furnace center height position on each wall, The deviation of heat absorption peculiar to the furnace is leveled by connecting to the heat transfer tube at another upper position so as to cancel the fluid condition difference due to the position in the furnace width direction of the furnace peripheral wall heat transfer tube below the tube draw position. It will be transformed. Further, at that time, the fluid moves in the pipe header, and thereby the fluids are mixed at the same time, so that the mixing effect becomes large in combination with both of them. In particular, the fifth embodiment is a system in which the central portion in the furnace width direction and the left and right corners are interchanged at the upper and lower sides of the tube shift, and the heat absorption by the position in the furnace width direction of the furnace peripheral wall heat transfer tube above the burner level of the furnace peripheral wall is absorbed. Considering the characteristics, the leveling effect is considered to be great.

[0033]

EFFECTS OF THE INVENTION According to the present invention, the temperature imbalance of the furnace wall metal, which has been conventionally generated when the load is lowered during partial load operation of the supercritical pressure transformer once-through boiler, does not dynamically occur. The life of the pressure-resistant portion of the furnace is not consumed due to repeated thermal stress generated, and further, there is an effect of preventing damage to the boiler furnace wall due to fatigue.

[Brief description of drawings]

FIG. 1 is a system diagram showing a supercritical pressure transformer once-through boiler according to a first embodiment of the present invention.

FIG. 2 is a system diagram showing in detail a furnace peripheral wall intermediate pipe pulling section of the above-mentioned supercritical pressure variable pressure once-through boiler.

FIG. 3 is a horizontal cross-sectional view (cross-section III-III in FIG. 4) showing the furnace peripheral wall intermediate pipe pulling portion.

FIG. 4 is a vertical sectional side view taken along the line IV-IV of FIG.

5 is a rear view taken along the line VV of FIG.

FIG. 6 is a partial detailed view of the furnace peripheral wall intermediate pipe pulling portion.

FIG. 7 is a side view taken along the line VII-VII of FIG.

FIG. 8 is a plan view showing a furnace peripheral wall intermediate pipe pulling portion in a second embodiment of the present invention.

9 is a lateral cross-sectional view taken along the line IX-IX of FIG.

FIG. 10 is a plan view showing a furnace peripheral wall intermediate pipe pulling portion in a third embodiment of the present invention.

11 is a lateral cross-sectional view taken along the line XI-XI of FIG.

12 is a lateral cross-sectional view taken along the line XII-XII of FIG.

FIG. 13 is a plan view showing a furnace peripheral wall intermediate pipe pulling portion in a fourth embodiment of the present invention.

14 is a lateral cross sectional view taken along the line XIV-XIV of FIG.

15 is a cross-sectional side view taken along the line XV-XV of FIG.

FIG. 16 is a plan view showing a furnace peripheral wall intermediate pipe pulling portion in a fifth embodiment of the present invention.

17 is a lateral cross-sectional view taken along the arrow XVII-XVII in FIG.

18 is a lateral cross sectional view taken along the line XVIII-XVIII of FIG.

FIG. 19 is the furnace static characteristic data of the supercritical pressure transformer once-through boiler.

FIG. 20 is a system diagram showing an example of a configuration of a conventional supercritical pressure variable pressure once-through boiler.

FIG. 21 is a diagram showing an example of furnace characteristics of a conventional supercritical pressure variable pressure once-through boiler.

FIG. 22 is a diagram showing another example of furnace characteristics of a conventional supercritical pressure variable pressure once-through boiler.

[Fig. 23] Fig. 23 is a perspective view showing an example of a furnace peripheral wall intermediate pipe provided in a conventional variable pressure once-through boiler.

FIG. 24 is a view exemplifying a fluid temperature distribution in a furnace peripheral wall intermediate pipe inlet / outlet portion.

[Explanation of symbols]

(1) Furnace inlet connection pipe (2) Furnace peripheral wall evaporation pipe (3) Furnace peripheral wall evaporation pipe outlet (4) Furnace peripheral wall evaporation pipe inlet pipe (5) Furnace peripheral wall evaporation pipe outlet pipe (6) Furnace outlet communication pipe ( 7) Steam separator (8) Drain discharge pipe (9) Superheater (10) Drain level control valve (11) Circulation pump (12) Rear flue (13) Superheater inlet connection pipe (14) Furnace (15) Upper furnace peripheral wall heat transfer pipe (16) Lower furnace peripheral wall heat transfer pipe (17) Upper furnace peripheral wall pipe inlet pipe (18) Upper furnace peripheral wall pipe outlet pipe (19) Mixer (20) Lower furnace peripheral wall pipe inlet pipe (21) ) Lower furnace peripheral wall pipe outlet outlet (22), (22a), (22b) Furnace peripheral wall intermediate outlet (25), (26) Pipe divider

Claims (6)

[Claims] 1. A furnace having a peripheral wall formed of a heat transfer tube,
A burner for injecting fuel and combustion air into the lower part of the furnace for combustion is provided, and the combustion gas generated in the furnace rises while being absorbed by the peripheral wall of the furnace and rises from the upper part of the furnace to the rear flue. In the critical pressure transformer once-through boiler, the furnace peripheral wall is divided into upper and lower parts, and the lower furnace peripheral wall tube outlet pipe header connected to the outlet of the heat transfer tube forming the lower furnace peripheral wall and the transfer forming the upper furnace peripheral wall are connected. An upper furnace peripheral wall pipe inlet header connected to the inlet of the heat pipe, and a mixer connected to the lower furnace peripheral wall pipe outlet header and the upper furnace peripheral wall pipe inlet header are provided. Pressure-transforming once-through boiler. 2. A furnace having a peripheral wall formed of a heat transfer tube,
A burner for injecting fuel and combustion air into the lower part of the furnace for combustion is provided, and the combustion gas generated in the furnace rises while being absorbed by the peripheral wall of the furnace and rises from the upper part of the furnace to the rear flue. In the critical pressure once-through boiler, the furnace peripheral wall is divided into upper and lower parts, and is connected to both the outlet of the heat transfer tube forming the lower furnace peripheral wall and the inlet of the heat transfer tube forming the upper furnace peripheral wall and crossing 18 in the center of the plane
A supercritical pressure transformer once-through boiler, which is provided with a header having a partition wall twisted by 0 °. 3. A furnace having a peripheral wall composed of a heat transfer tube,
A burner for injecting fuel and combustion air into the lower part of the furnace for combustion is provided, and the combustion gas generated in the furnace rises while being absorbed by the peripheral wall of the furnace and rises from the upper part of the furnace to the rear flue. In the critical pressure once-through boiler, the peripheral wall of the furnace is divided into upper and lower parts, and a pipe partitioning into two chambers is provided for each wall surface of the peripheral wall of the furnace under the respective wall surfaces. The outlet of the heat transfer tube forming the left side half is connected to one of the rooms, the outlet of the heat transfer tube forming the lower right half of each wall is connected to the other side of the room, and The inlet of the heat transfer tube forming the upper right half is connected to the one side of the room, and the inlet of the heat transfer tube forming the upper left half of each wall is connected to the other side of the room. Supercritical pressure transformer once-through boiler. 4. A furnace having a peripheral wall formed of a heat transfer tube,
A burner for injecting fuel and combustion air into the lower part of the furnace for combustion is provided, and the combustion gas generated in the furnace rises while being absorbed by the peripheral wall of the furnace and rises from the upper part of the furnace to the rear flue. In the critical pressure once-through boiler, the peripheral wall of the furnace is divided into upper and lower parts, and a pipe partitioning into two chambers is provided for each wall surface of the peripheral wall of the furnace under the respective wall surfaces. The outlet of the heat transfer tube that constitutes the left and right side corners is connected to one of the chambers, the outlet of the heat transfer tube that constitutes the lower center of each of the wall surfaces is connected to the other of the room, and the upper side of each of the wall surfaces is connected. The supercritical characterized in that the inlet of the heat transfer tube forming the central portion is connected to the one side of the room, and the inlet of the heat transfer tube forming the upper left and right corners of each wall surface is connected to the other side of the room, respectively. Voltage-transforming once-through boiler 5. A furnace having a peripheral wall formed of a heat transfer tube,
A burner for injecting fuel and combustion air into the lower part of the furnace for combustion is provided, and the combustion gas generated in the furnace rises while being absorbed by the peripheral wall of the furnace and rises from the upper part of the furnace to the rear flue. In a critical pressure transformer once-through boiler, the peripheral wall of the furnace is divided into upper and lower parts, and a set of two pipes is provided for each wall surface of the peripheral wall of the furnace, and a lower left half part of each wall surface is constituted. The outlet of the heat pipe is connected to one of the two pairs of the headers, the outlet of the heat transfer tube forming the lower right half of each wall is connected to the other of the headers, and the upper side of each wall is connected. The inlet of the heat transfer tube that constitutes the right half part is connected to the one of the above-mentioned tube headers, and the inlet of the heat transfer tube that constitutes the upper left half part of each wall surface is connected to the other of the above-mentioned tube headers, respectively. Supercritical pressure transformer once-through boiler. 6. A furnace having a peripheral wall composed of a heat transfer tube,
A burner for injecting fuel and combustion air into the lower part of the furnace for combustion is provided, and the combustion gas generated in the furnace rises while being absorbed by the peripheral wall of the furnace and rises from the upper part of the furnace to the rear flue. In the critical pressure transformer once-through boiler, the peripheral wall of the furnace is divided into upper and lower parts, and a set of two pipes is provided for each wall surface of the peripheral wall of the furnace, and the lower left and right corners of each wall surface are formed. The outlet of the heat pipe is connected to one of the two pairs of the headers, and the outlet of the heat transfer tube forming the lower central portion of each wall surface is connected to the other of the headers,
Further, the inlet of the heat transfer tube forming the upper center portion of each wall surface is connected to the one of the headers, and the inlet of the heat transfer tube forming the upper left and right corners of each wall surface is connected to the other of the header. A supercritical pressure variable pressure once-through boiler.