JP6896382B2 - Boiler gas flow adjustment method, boiler and power generation system - Google Patents

Description

The present invention relates to a boiler gas flow adjusting method, a boiler and a power generation system.

Inside the duct of the exhaust heat recovery steam generator (HRSG) used in thermal power plants, exhaust gas with a heat recoverable temperature such as combustion gas flows, and a heat exchanger is provided to exchange heat with water supply and steam. Has been done. FIG. 19 shows a Gas Turbine Combined Cycle (GTCC) power generation system with an exhaust heat recovery steam generator (HRSG) in which the heat exchanger is applied as a low pressure economizer 53. The gas turbine combined cycle power generation system shown in FIG. 19 will be described later as an application example of the invention according to the embodiment of the present invention.

For example, as shown in FIGS. 15 to 17, the heat exchanger 10 is formed so that exhaust gas flows in the direction of the arrow from one side (lower side of the paper surface) to the other side (upper side of the paper surface) inside the duct 12. Has been done. A plurality of heat transfer tube blocks 13 are arranged in the heat exchanger 10, and the heat transfer tube block 13 has a plurality of heat transfer tubes 30 as shown in FIG. 17 (a diagram cut in a direction orthogonal to the cutting direction of FIG. 16). It is composed of.

As shown in FIGS. 15 and 16, the heat transfer tube block 13 is provided with a predetermined gap between adjacent heat transfer tube blocks 13 from the viewpoint of manufacturing, construction, and the like. As shown by the thin arrow in FIG. 15, when the exhaust gas passes through the gap between the heat transfer tube blocks 13, that is, a part of the exhaust gas does not pass through the plurality of heat transfer tubes 30 constituting the heat transfer tube block 13. In the case of a short pass, the amount of heat recovered from the heat transfer tube 30 with the exhaust gas is reduced. Therefore, as shown in FIGS. 16 and 17, the closing plate 11 is conventionally arranged in the gap provided between the adjacent heat transfer tube blocks 13. As a result, a part of the flow of the exhaust gas that tries to pass through the gap between the heat transfer tube blocks 13 is blocked by the closing plate 11, and the exhaust gas flows to the heat transfer tube 30 side without short-passing, so that the heat transfer tube 30 It is possible to recover heat from the exhaust gas.

Patent Document 1 below describes that a plurality of baffle plates are inserted between heat transfer tubes constituting a reheater. It is described that the gas flow velocity between the heat transfer tubes is increased by reducing the cross-sectional area of the exhaust gas flow path. Further, Patent Document 2 below describes that a bypass damper for adjusting the amount of gas bypass is provided in the gas bypass path provided in a part of the tube group of the evaporator. By adjusting the opening degree of the bypass damper to adjust the amount of bypass, the endothermic ratio between the evaporator and the heat exchanger on the downstream side of the exhaust gas is optimized. Further, Patent Document 3 below also describes a flow rate adjusting mechanism for adjusting the flow rate of exhaust gas bypassing the heater in the exhaust gas flow path provided in the superheater.

Japanese Unexamined Patent Publication No. 2000-161647 JP-A-2007-298244 JP-A-2010-144997

The exhaust gas flowing through the exhaust heat recovery boiler is exhaust gas having a temperature at which heat recovery is possible, which is discharged from the outlet of the gas turbine (GT). Since the air density of the air used for combustion in the combustor of the gas turbine changes depending on the season (change in outside temperature), the pressure of the exhaust gas (GT exhaust gas) of the gas turbine fluctuates according to the season. In the summer when the outside air temperature is high and the air density is low, the flow rate of the GT exhaust gas decreases and the exhaust gas pressure decreases, and in the winter when the outside air temperature is low and the air density is high, the GT exhaust gas flow rate increases and the exhaust gas pressure. Rise.

By the way, during the operation of the exhaust heat recovery boiler, if the pressure of the exhaust gas in the exhaust heat recovery boiler rises and exceeds a predetermined value, it is determined that the pressure of the GT exhaust gas becomes high and the GT operation continuation is hindered. Therefore, it is necessary to shut down the thermal power plant. In a thermal power plant, etc., after many years of operation, the pressure loss may increase when the exhaust gas passes through the exhaust heat recovery boiler due to the scale attached to the heat exchanger of the exhaust heat recovery boiler. .. Therefore, especially in winter when the air density is high and the flow rate of GT exhaust gas increases and the pressure rises, the pressure loss when the exhaust gas passes through in the exhaust heat recovery boiler increases, and the pressure of GT exhaust gas exceeds a predetermined value. Therefore, there is a high possibility that it will be judged that it is difficult to continue the operation.

Therefore, in order to reduce the pressure loss when the exhaust gas passes through the exhaust heat recovery boiler, the increase in pressure loss is expected without allowing a part of the exhaust gas to pass through the plurality of heat transfer tube sides constituting the heat transfer tube block. It is conceivable that a part of the exhaust gas is intentionally short-passed from the beginning. However, if the exhaust gas does not pass through the heat transfer tube and the short pass is continued at all times, the heat recovery efficiency from the exhaust gas will be reduced to some extent. Therefore, always short-passing the exhaust gas throughout the year is a factor that lowers the heat recovery efficiency. Therefore, it is not preferable to improve the performance of the entire plant such as a thermal power generation plant.

The present invention has been made in view of such circumstances, and suppresses a decrease in heat recovery efficiency throughout the year to increase an excessive pressure loss when exhaust gas passes through the boiler. It is an object of the present invention to provide a boiler gas flow adjusting method, a boiler and a power generation system capable of suppressing an increase in pressure of GT exhaust gas.

In order to solve the above problems, the boiler gas flow adjusting method, the boiler and the power generation system of the present invention employ the following means.
That is, in the method for adjusting the gas flow of the boiler according to the present invention, the length of the heat transfer tube is formed at the upper end in the vertical direction of the gap formed between the heat transfer tube block having a plurality of heat transfer tubes and the adjacent heat transfer tube blocks. A method for adjusting the gas flow of a boiler, which is installed so that the direction along the direction is the longitudinal direction and includes a closing plate that obstructs the flow of gas that tries to pass through the gap, and is supplied to the outside air temperature or the boiler. It has a step of attaching or detaching the closing plate according to the pressure of the gas.

According to this configuration, the closing plate is attached or removed according to the outside air temperature or the pressure loss of the gas (exhaust gas) supplied to the heat transfer tube block. From this, for example, when the air density is low and the exhaust gas flow rate of the GT is reduced and the exhaust gas pressure loss inside the boiler tends to be low, a closing plate between the heat transfer tube blocks is attached to improve the heat recovery efficiency. Improve. On the other hand, when the air density is high and the exhaust gas flow rate of GT increases and the exhaust gas pressure loss inside the boiler tends to increase, the closing plate is removed to reduce the exhaust gas pressure loss and the GT exhaust gas pressure. Can be reduced. If the period during which the closing plate is removed can be shortened, the period during which the heat recovery efficiency decreases can be shortened, and the GT and the boiler can be operated throughout the year while suppressing the decrease in the heat recovery efficiency. The direction perpendicular to the cross section of the duct through which the gas of the exhaust heat recovery boiler flows is the vertical direction.

In the above invention, the outside air temperature is is lower than a predetermined threshold value, a step of removing the closing plate, when the outside air temperature is equal to or greater than a predetermined threshold, the organic and attaching the closing plate.

According to this configuration, since the outside air temperature is low, the closing plate is removed during the period when the air density is high and the GT exhaust gas flow rate increases and the pressure loss when the exhaust gas passes through the boiler tends to increase. Therefore, the pressure loss can be reduced and the operation of the GT and the boiler can be continued. On the other hand, since the outside air temperature is high, the air density is low and the exhaust gas flow rate of the GT is reduced, so that the exhaust gas pressure loss inside the boiler tends to be low. During a period of time, a closing plate can be attached to improve heat recovery efficiency. That is, since the period for removing the closing plate and the period for attaching the closing plate are determined according to the outside air temperature, it is possible to systematically carry out the removing and attaching work of the closing plate by utilizing the period when the boiler is stopped. ..

In the above invention, when the pressure of the gas supplied to the heat transfer tube block is higher than a predetermined threshold value, the step of removing the closing plate and the pressure of the gas supplied to the heat transfer tube block are equal to or lower than the predetermined threshold value. when it is closed and attaching the closing plate.

According to this configuration, the closing plate is removed during the period when the air density is high and the pressure of the gas (exhaust gas) supplied to the heat transfer tube block, that is, the exhaust gas pressure inside the boiler tends to be high, and the inside of the boiler is removed. Reduces pressure loss when exhaust gas passes through. On the other hand, during the period when the air density is low and the pressure of the gas supplied to the heat transfer tube block, that is, the exhaust gas pressure inside the boiler tends to be low, a closing plate can be attached to improve the heat recovery efficiency.

The boiler according to the reference example of the present invention has a direction along the longitudinal direction of the heat transfer tube at the upper end in the vertical direction of the gap formed between the heat transfer tube block having a plurality of heat transfer tubes and the adjacent heat transfer tube block. Is installed so as to be in the longitudinal direction, and includes a closing plate that obstructs the flow of gas that tries to pass through the gap, and the closing plate has a weight that does not move due to the fluid force of the gas supplied to the heat transfer tube block. Has.

According to this configuration, since the closing plate is maintained in a state of being attached by its own weight, it is not necessary to attach the closing plate to the heat transfer tube block by welding, and the closing plate can be easily removed and attached. be able to.

The boiler according to the reference example of the present invention has a direction along the longitudinal direction of the heat transfer tube at the upper end in the vertical direction of the gap formed between the heat transfer tube block having a plurality of heat transfer tubes and the adjacent heat transfer tube block. Is installed so as to be in the longitudinal direction, and a closing plate that obstructs the flow of gas that tries to pass through the gap, and a plate that is provided on the upper surface of the heat transfer tube block in the vertical direction along the longitudinal direction of the heat transfer tube. A guide member having a shaped member is provided, and the end face of the closing plate is provided in contact with the guide member.

According to this configuration, at least a part of the horizontal end face of the closing plate comes into contact with the guide member, so that the position of the closing plate is less likely to shift in the horizontal direction, and a gap is generated between the closing plate and the heat transfer tube block. This prevents a part of the exhaust gas from passing through in a short pass.

In the above reference example , the lower surface of the closing plate in the vertical direction is a plate-shaped member provided in a direction orthogonal to the longitudinal direction of the closing plate, and is in a vertical direction equal to or greater than a gap between adjacent heat transfer tube blocks. A first auxiliary plate having a height extending to may be provided.

According to this configuration, the auxiliary plate improves the rigidity of the closing plate and suppresses deformation, so that a gap between the closing plate and the heat transfer tube block prevents part of the exhaust gas from passing through in a short path. To do. In addition, since an auxiliary plate having a height higher than the gap between adjacent heat transfer tube blocks is provided, the closing plate can be used as a heat transfer tube block when the closing plate moves unexpectedly or when the closing plate is removed and attached. It can be prevented from falling from between.

In the above reference example , the vertical upper surface of the closing plate may be provided with a handle portion having a height along the vertical direction that is equal to or greater than the gap between the adjacent heat transfer tube blocks.

According to this configuration, since the handle portion having a height equal to or higher than the gap between the adjacent heat transfer tube blocks is provided, it is possible to prevent the closing plate from falling from between the heat transfer tube blocks.

In the above reference example , between the adjacent heat transfer tube blocks, a plurality of second auxiliary plates, which are plate-like members provided in a direction orthogonal to the main surface of the closing plate, have at least one end side of the heat transfer tube block. The installation interval between the second auxiliary plates, which are joined to each other and installed corresponding to the closing plate, may be smaller than the gap between the heat transfer tube blocks.

According to this configuration, since the installation interval of the plurality of auxiliary plates provided between the heat transfer tube blocks for each closing plate is smaller than the gap between the heat transfer tube blocks, the closing plates are placed between the heat transfer tube blocks. It can be prevented from falling.

The boiler according to the reference example of the present invention has a direction along the longitudinal direction of the heat transfer tube at the vertical upper end of the gap formed between the heat transfer tube block having a plurality of heat transfer tubes and the adjacent heat transfer tube block. Is installed so as to be in the longitudinal direction, and is provided on the vertical upper surface of the heat transfer tube block and a closing plate that obstructs the flow of gas that tries to pass through the gap, and is bent toward the gap between the heat transfer tube blocks. It is provided with a fixture having a shaped shape and a stopper having an inclined surface whose height changes in the vertical direction, which is inserted into a gap between the fixture and the closing plate.

According to this configuration, the closing plate is fixed to the heat transfer tube block by the fixture and the stopper. The closing plate and the fixture, and the fixture and the stopper are fixed by, for example, welding or spot welding to the extent that they do not move easily. In this case, the number of welded parts can be reduced as compared with the case where the closing plate is fixed to the heat transfer tube block by full-circle welding. Therefore, the work of removing and attaching the closing plate can be easily performed.

The boiler according to the reference example of the present invention has a direction along the longitudinal direction of the heat transfer tube at the upper end in the vertical direction of the gap formed between the heat transfer tube block having a plurality of heat transfer tubes and the adjacent heat transfer tube block. Is installed so as to be in the longitudinal direction, and the closing plate that obstructs the flow of gas that tries to pass through the gap is sandwiched between the heat transfer tube block and the closing plate, and the closing plate is tightened against the heat transfer tube block. It is equipped with a clamp that is fixed by force.

According to this configuration, the clamp sandwiches the heat transfer tube block and the closing plate, so that the closing plate is fixed to the heat transfer tube block by the clamp. In this case, the number of welded parts can be reduced as compared with the case where the closing plate is fixed to the heat transfer tube block by full-circle welding. Therefore, the work of removing and attaching the closing plate can be easily carried out.

The boiler according to the reference example of the present invention has a direction along the longitudinal direction of the heat transfer tube at the vertical upper end of the gap formed between the heat transfer tube block having a plurality of heat transfer tubes and the adjacent heat transfer tube block. Is installed so as to be in the longitudinal direction, and is provided with a closing plate that obstructs the flow of gas that tries to pass through the gap, and in the gap of the heat transfer tube block, the direction in which the closing plate is along the longitudinal direction of the heat transfer tube is A plurality of them are arranged so as to be in the longitudinal direction, and the longitudinal end portion of the closing plate has a step structure that is fitted to each other with the longitudinal end portion of the adjacent closing plate.

According to this configuration, the longitudinal (longitudinal) end of the closing plate is constrained by the end of another adjacent closing plate, so that the heat elongation difference due to the temperature difference between the vertical upper surface and the bottom surface of the closing plate. Deformation (warp) of the end of the closing plate due to the above is suppressed, a gap is generated between the closing plate and the heat transfer tube block, and a part of the exhaust gas is suppressed from passing through in a short path.

The power generation system according to the reference example of the present invention comprises a gas turbine driven by a high-temperature and high-pressure gas generated by burning fuel gas, the above-mentioned boiler to which exhaust gas generated by the gas turbine is supplied, and the above-mentioned boiler. A steam turbine driven by the discharged steam and a gas turbine and a generator driven by the rotational force of the steam turbine are provided.

According to the present invention, it is possible to suppress a decrease in heat recovery efficiency throughout the year, suppress an increase in pressure loss due to excessive exhaust gas, and suppress an increase in pressure of GT exhaust gas.

It is a vertical cross-sectional view which shows the closing plate structure between the heat transfer tube blocks which concerns on 1st Embodiment of this invention. It is a perspective view which shows the closing plate structure between the heat transfer tube blocks which concerns on 1st Embodiment of this invention. It is a perspective view which shows the 1st modification of the closing plate structure between the heat transfer tube blocks which concerns on 1st Embodiment of this invention. It is a perspective view which shows the 2nd modification of the closing plate structure between the heat transfer tube blocks which concerns on 1st Embodiment of this invention. It is a perspective view which shows the 3rd modification of the closing plate structure between the heat transfer tube blocks which concerns on 1st Embodiment of this invention. It is a perspective view which shows the 3rd modification of the closing plate structure between the heat transfer tube blocks which concerns on 1st Embodiment of this invention, and shows the state which the closing plate is removed. It is a vertical cross-sectional view which shows the closing plate structure between the heat transfer tube blocks which concerns on 2nd Embodiment of this invention. It is a side view which shows the closing plate structure between the heat transfer tube blocks which concerns on 2nd Embodiment of this invention. It is a top view which shows the closing plate structure between the heat transfer tube blocks which concerns on 2nd Embodiment of this invention. It is a side view which shows the 1st modification of the closing plate structure between the heat transfer tube blocks which concerns on 2nd Embodiment of this invention. It is a vertical cross-sectional view which shows the 2nd modification of the closing plate structure between the heat transfer tube blocks which concerns on 2nd Embodiment of this invention. It is a partially enlarged vertical sectional view which shows the 2nd modification of the closing plate structure between the heat transfer tube blocks which concerns on 2nd Embodiment of this invention. It is a partially enlarged vertical sectional view which shows the 3rd modification of the closing plate structure between the heat transfer tube blocks which concerns on 2nd Embodiment of this invention. It is a perspective view which shows the closing plate structure between the heat transfer tube blocks which concerns on 3rd Embodiment of this invention. It is a vertical cross-sectional view which shows the heat transfer tube block. It is a vertical cross-sectional view which shows the heat transfer tube block and the closing plate. It is a vertical cross-sectional view which shows the heat transfer tube block and the closing plate, and is the figure which cut in the direction orthogonal to the cutting direction of FIG. It is a perspective view which shows the closing plate installed in the gap between the heat transfer tube blocks. It is a schematic block diagram which shows the gas turbine combined cycle power generation system which includes the exhaust heat recovery boiler.

[First Embodiment]
FIG. 1 shows the inside of the duct 12 of the exhaust heat recovery boiler (HRSG) used in a thermal power plant or the like. The direction perpendicular to the cross section of the exhaust gas passage of the duct 12 of the exhaust heat recovery boiler is defined as the vertical direction. In FIG. 1, the direction in which the exhaust gas flows is the vertical direction, and in the vertical exhaust heat recovery boiler 42 as shown in FIG. 19, the vertical direction is substantially the vertical direction. In the arrangement direction of the duct 12, the vertical direction does not necessarily have to be along the vertical direction. As shown in FIG. 1, the heat exchanger 10 is installed, and in the present embodiment, the exhaust gas (gas) is vertical from one side (lower side of the paper surface) of the heat exchanger 10 to the other side (upper side of the paper surface). It flows in the direction indicated by the arrow. A plurality of heat transfer tube blocks 13 are arranged in the heat exchanger 10, and the heat transfer tube block 13 is composed of a plurality of heat transfer tubes 30, and water supply and steam circulating in the heat transfer tube 30 exchange heat with exhaust gas. do. A predetermined gap is provided between the adjacent heat transfer tube blocks 13 from the viewpoint of manufacturing, construction, and the like. In the gap between the heat transfer tube block 13 and the duct 12, a fixing plate 14 is installed at one end of the upper surface of the heat transfer tube block 13 in the vertical direction so that the exhaust gas does not pass through in a short pass.

In the present embodiment, in order to prevent the heat recovery efficiency of the heat exchanger 10 from decreasing throughout the year, a closing plate 11 is arranged for a certain period of time in the gap provided between the adjacent heat transfer tube blocks 13 to exhaust gas. Is short-passed to prevent it from passing through, or the closing plate 11 is removed during another period to allow a part of the exhaust gas to pass through by short-passing without passing through the plurality of heat transfer tubes 30. ..

During the period when the outside air temperature is low, the air density is high and the exhaust gas flow rate of the GT increases, so that the pressure loss when the exhaust gas passes through the exhaust heat recovery boiler tends to increase. During this period, the closing plate 11 is removed to reduce the pressure loss and allow the GT and the exhaust heat recovery boiler to continue operation.

On the other hand, during the period when the outside air temperature is high, the air density is low and the exhaust gas flow rate of the GT is reduced, so that the exhaust gas pressure loss inside the exhaust heat recovery boiler tends to be low. During this period, the closing plate 11 is attached, and the heat recovery efficiency of the heat exchanger 10 can be improved.

Further, it is possible to make a judgment based on the pressure of the exhaust gas (GT exhaust gas) of the gas turbine regardless of the measurement of the outside air temperature. During the period when the air density is high and the pressure of the exhaust gas supplied to the heat transfer tube block 13, that is, the exhaust gas pressure inside the exhaust heat recovery boiler tends to be high, the closing plate 11 is removed and the exhaust gas inside the exhaust heat recovery boiler is removed. Reduces pressure loss as it passes.

On the other hand, during the period when the air density is low and the pressure of the gas supplied to the heat transfer tube block 13, that is, the exhaust gas pressure inside the exhaust heat recovery boiler tends to be low, the closing plate 11 is attached to the heat exchanger 10. The heat recovery efficiency can be improved.

That is, by setting an appropriate outside air temperature or GT exhaust gas pressure according to the specifications and operating conditions of the GT and the exhaust heat recovery boiler as a predetermined threshold, the GT exhaust gas can be adjusted according to the outside air temperature. It is possible to systematically carry out the removal and installation work of the closing plate 11 by determining the period for removing and installing the closing plate 11 according to the pressure and using the stop period of the exhaust heat recovery boiler or the like. It becomes.

The outside air temperature is measured by the intake inlet of the gas turbine. The pressure of the GT exhaust gas is measured by a pressure gauge (not shown) provided on the exhaust gas outlet side of the gas turbine.

The closing plate 11 installed in the gap between the heat transfer tube blocks 13 has a vertical length (in the direction orthogonal to the paper surface) that covers the vertical length of the heat transfer tube block 13, and the horizontal horizontal lengths are adjacent to each other. It is a length that covers the width of the gap between the heat transfer tube blocks 13. In addition, the plate thickness in the vertical direction is such that warpage deformation is unlikely to occur and can be fixed by welding or the like. In the present embodiment, for example, the length is about 2,000 to 4,000 mm, the width is 50 to 200 mm, and the plate thickness is about 3 to 5 mm. By arranging the closing plate 11 so that a part of the exhaust gas does not pass through the heat transfer tube block 13 by short-passing, the exhaust gas passes around the heat transfer tube 30, so that the heat recovery efficiency of the heat exchanger 10 is reduced. Can be suppressed. However, in this state, the pressure loss due to the flow of the exhaust gas in the exhaust heat recovery boiler becomes high when the flow rate of the GT exhaust gas increases. On the other hand, by removing the closing plate 11 and passing a part of the exhaust gas through a short pass without passing around the plurality of heat transfer tubes 30, the pressure loss of the exhaust gas in the exhaust heat recovery boiler can be reduced. However, in this state, the heat recovery efficiency of the heat exchanger 10 is slightly reduced.

Specifically, the period when the air density of the air used for combustion by the gas turbine increases and the exhaust gas flow rate increases, that is, the period when the outside air temperature decreases or the period when the GT exhaust gas pressure increases (mainly in winter) is a closing plate. Remove 11 On the other hand, the closing plate 11 is attached during the period when the air density of the air used by the gas turbine for combustion decreases and the exhaust gas flow rate decreases, that is, the period when the outside air temperature rises or the GT exhaust gas pressure decreases (mainly in summer). ..

In winter, a part of the exhaust gas passes through the part where the closing plate 11 is removed (the gap between the heat transfer tube blocks 13), and a part of the exhaust gas passes through the heat transfer tube 30 without passing through the short pass. The heat recovery efficiency of the heat exchanger 10 is reduced. However, since it becomes difficult for the exhaust gas pressure in the exhaust heat recovery boiler to rise to an excessive amount, it becomes difficult for the exhaust gas pressure to exceed a predetermined value, and it is judged that the GT is in a state of refraining from continuing operation. Absent. As described above, there is an advantage that the GT and the exhaust heat recovery boiler can be easily continued to operate only by removing the closing plate 11. On the other hand, in the summer, the closing plate 11 prevents a part of the exhaust gas from passing through in a short pass, and the exhaust gas passes around the heat transfer tube 30, so that the decrease in the heat recovery efficiency of the heat exchanger 10 is suppressed. it can. In the summer, the air density is low, the exhaust gas flow rate decreases, the pressure loss of the exhaust gas in the exhaust heat recovery boiler is small, and the pressure of the GT exhaust gas does not rise. The increase in pressure loss due to the exhaust gas flow of the recovery boiler does not hinder the continuation of GT operation. By attaching or detaching the closing plate 11 to or from the gap between the heat transfer tube blocks 13, the pressure loss due to the exhaust gas flow of, for example, 0.1 kPa to 0.5 kPa can be adjusted, and the fluctuation of the pressure of the GT exhaust gas can be absorbed. preferable.

[Modification 1 of the first embodiment]
Conventionally, the closing plate 11 is left attached, and the closing plate 11 is fixed by full-circle welding as shown in FIG. 18 to prevent a part of the exhaust gas from leaking and passing between the closing plate 11 and the heat transfer tube block 13. There is. In FIG. 18, the welded portion is represented by the reference numeral W. Therefore, in order to attach or detach the closing plate 11 according to the outside air temperature or the pressure of the exhaust gas (GT exhaust gas) of the gas turbine, for example, at the transition time between summer and winter, it is necessary to perform full-circle welding. Rather than fixing the closing plate 11, it is desirable to adopt the following configuration to improve the workability of attaching and detaching.

In the present embodiment, the exhaust gas flows in the vertical upward direction, which is the direction indicated by the arrow in FIG. 1, so that the closing plate 11 is the upper surface of the heat transfer tube block 13 in the vertical direction as shown in FIG. It is arranged so as to close the gap between the heat tube blocks 13.

The closing plate 11 is, for example, a steel plate, and the surface thereof may be subjected to a surface treatment to prevent corrosion. The thickness of the closing plate 11 is, for example, a thick plate of about t10 mm to t30 mm, and the weight of the closing plate 11 is such that the closing plate 11 does not rise due to the pressure due to the fluid force of the exhaust gas. By setting the weight of the closing plate 11 in this way, the closing plate 11 is maintained in a state of being attached by its own weight, so that it is not necessary to attach the closing plate 11 to the heat transfer tube block 13 by welding, and the closing plate 11 is closed. The plate 11 can be attached / detached in a short period of time.

Further, as shown in FIGS. 1 and 2, when the closing plate 11 is installed on the upper surface of the heat transfer tube block 13 in the vertical direction, the guide hardware (L-shape) facing the end faces at both ends in the horizontal direction of the closing plate 11 is formed. The hardware) 15 may be installed on the upper surface of the heat transfer tube block 13 in the vertical direction in contact with at least a part of the end surface of the closing plate 11. By providing the guide hardware 15, the position of the closing plate 11 is less likely to shift in the horizontal direction. As a result, even if the closing plate 11 receives vibration during boiler operation or the fluid force of the exhaust gas, it is possible to prevent the displacement in the horizontal direction, and a gap is generated between the closing plate 11 and the heat transfer tube block 13 to generate the exhaust gas. It is preferable because it suppresses the passage of a part of the short pass.

The guide hardware 15 has a horizontal portion 15a and a vertical portion 15b, and the horizontal portion 15a has a main surface extending in the horizontal direction and is placed on the vertical upper surface of the heat transfer tube block 13. The vertical portion 15b is provided so as to extend in the vertical direction which is orthogonal to the horizontal portion 15a.

[Modification 2 of the first embodiment]
Further, in the present embodiment, as shown in FIG. 3, the first auxiliary plate 16 may be attached to the bottom surface of each closing plate 11. The first auxiliary plate 16 has, for example, a width of 30 to 100 mm, a height of 100 to 200 mm, and a plate thickness of about 3 to 10 mm. FIG. 3 shows a state in which the description of the heat transfer tube block 13 and the guide hardware 15 on the front side is omitted, unlike FIG. 2, in order to make the arrangement structure easy to understand. The first auxiliary plate 16 is attached by welding in a direction orthogonal to the bottom surface of the closing plate 11 near the center in the longitudinal direction of the closing plate 11 extending in the vertical direction. The rigidity of the closing plate 11 can be improved by the first auxiliary plate 16, and warpage deformation due to a temperature difference or the like can be suppressed. Further, the total length (β) of the height of the first auxiliary plate 16 and the plate thickness of the closing plate 11 is longer than the width (α) of the gap between the heat transfer tube blocks 13. Even if the closing plate 11 moves in an unpredictable situation, or when the closing plate 11 is removed and attached, the closing plate 11 may come off from the guide hardware 15 in the vertical downward direction (vertically downward in the present embodiment). , It is possible to prevent the closing plate 11 from falling into the gap between the heat transfer tube blocks 13.

[Modification 3 of the first embodiment]
Further, in the present embodiment, as shown in FIG. 4, although the first auxiliary plate 16 is not attached, the height of the handle portion 17 is increased, and the plate thickness of the closing plate 11 and the height of the handle portion 17 (γ) are increased. ) May be larger than the width (α) of the gap between the heat transfer tube blocks 13. The handle portion 17 is attached by welding in a direction orthogonal to the vertical upper surface of the closing plate 11 near the center in the longitudinal direction of the closing plate 11 extending in the vertical direction. Also in this case, even if the closing plate 11 is pulled out from the guide hardware 15 in the vertical downward direction (vertically downward in the present embodiment), the closing plate 11 falls into the gap between the heat transfer tube blocks 13. Can be prevented.

[Modification 4 of the first embodiment]
Further, in the above description of FIG. 3, the case where the first auxiliary plate 16 is installed on the bottom surface of the closing plate 11 has been described, but as shown in FIGS. 5 and 6, at least one second auxiliary plate 18 is provided. , At least one end of the second auxiliary plate 18 in the horizontal direction may be attached to the heat transfer tube block 13 by welding or the like so as to be installed in the gap between the heat transfer tube blocks 13. It is more preferable that two or more pairs of the second auxiliary plates 18 are provided for each closing plate 11. In this case, a plurality of second auxiliary plates 18 are installed side by side along the vertical direction (longitudinal direction of the closing plate 11) of the gap between the heat transfer tube blocks 13 and are provided in a ladder shape. The installation interval (δ) of the second auxiliary plate 18 is made smaller than the width of the gap (α) between the heat transfer tube blocks 13 for each closing plate 11, so that the closing plate 11 is tentatively below the guide hardware 15. Even if it comes off in the direction (vertically downward in the present embodiment), it is possible to prevent the closing plate 11 from falling into the gap between the heat transfer tube blocks 13.

[Second Embodiment]
Next, the closing plate structure according to the second embodiment of the present invention will be described.
In the above-described first embodiment, the case where the thickness of the closing plate 11 is a thick plate of about t10 mm to t30 mm has been described, but the present invention is not limited to this example.

As shown in FIGS. 7 to 10, the closing plate 11 has a conventional plate thickness (for example, about t3 to 5 mm), and the fixture 19 is welded and fixed to the heat transfer tube block 13 without making it a heavy object. , The closing plate 11 is inserted between the fixing tool 19 and the heat transfer tube block 13, and the closing plate 11 is fixed by inserting the stopper 20 between the closing plate 11 and the fixing tool.

As shown in FIGS. 7 and 8, the fixture 19 is provided so as to extend vertically upward from the vertical upper surface of the heat transfer tube block 13, and is bent toward the gap of the heat transfer tube block 13 at the upper part in the vertical direction. For example, it has an L-shape. The fixture 19 is fixed to the heat transfer tube block 13 by welding, fastening bolts, or the like. In FIG. 8, the fixed portion by welding is indicated by reference numeral W1.

When the closing plate 11 is installed between the gaps of the heat transfer tube block 13, the member of the fixture 19 that is bent toward the gap of the heat transfer tube block 13 at the upper end portion in the vertical direction is, for example, the closing plate 11. Is parallel to. Then, when the closing plate 11 is installed between the gaps of the heat transfer tube block 13, a stopper 20 having an inclined surface whose vertical length (height) changes in the vertical direction is inserted between the fixture 19 and the closing plate 11. It is possible. The fixtures 19 are, for example, vertical length: 20 to 50 mm × horizontal width: 50 to 100 mm × plate thickness: about 3 to 5 mm, and are installed one by one with a gap of the heat transfer tube block 13 in between. Will be done.

The stopper 20 has, for example, a wedge shape and has an inclined surface whose length (height) changes in the vertical direction. Between the fixture 19 and the closing plate 11, for example, it is inserted from the end side to the center side in the longitudinal direction of the closing plate 11, or from the center side to the end side in the longitudinal direction of the closing plate 11. Is inserted. The stopper 20 has a size of, for example, a height in the vertical direction: 10 to 30 mm × a horizontal direction: 30 to 50 mm × a plate thickness of about 10 to 20 mm. After being inserted between the fixture 19 and the closing plate 11, the stopper 20 is fixed to the fixture by spot welding so as not to easily move due to vibration during operation or the like. In FIGS. 8 and 9, the spot welded portion is indicated by reference numeral W2.

In this structure, the welded portion is limited between the fixture 19 and the heat transfer tube block 13 and between the fixture 19 and the stopper 20 (W1, W2). Therefore, as compared with the conventional fixing method (entire circumference welding), the number of welded points with the heat transfer tube block 13 is reduced, and the work period for attaching and detaching the closing plate 11 is shortened. The fixture 19 is a consumable item, and is replaced about once every several times of attaching and detaching the closing plate 11. Further, in order to prevent the stopper 20 from coming off due to vibration, the stopper 20 may be supported and fixed in a wedge shape (lower stopper 20A, upper stopper 20B) as shown in FIG. That is, in the stoppers 20 which are installed in pairs one by one with the gap of the heat transfer tube block 13 interposed therebetween, one lower stopper 20A is inserted from the end side to the center side in the longitudinal direction of the closing plate 11. The other upper stopper 20B is inserted from the central portion side to the end portion side in the longitudinal direction of the closing plate 11. It is more preferable that the lower stopper 20A, the upper stopper 20B, and the fixture are fixed by spot welding so as not to easily move due to vibration during operation or the like.

[Modification 1 of the second embodiment]
In the above-described embodiment, the configuration in which the closing plate 11 is fixed to the heat transfer tube block 13 by welding using the fixture 19 and the stopper 20 has been described, but the present invention is not limited to this example.

For example, as shown in FIGS. 11 and 12, the closing plate 11 may be fixed to the heat transfer tube block 13 by using a clamp 21 capable of holding a tightening force. The clamp 21 is, for example, a C-type clamp (also referred to as a mantis shrimp vise).

The clamps 21 are arranged, for example, at the four corners of the rectangular closing plate 11 so as to sandwich the heat transfer tube block 13 and the closing plate 11, and the tightening screws 22 of the clamp 21 are adjusted to face the movable base 23 and the fixing base. The closing plate 11 is fixed to and from 24 by a tightening force. Further, when the closing plate 11 has a long shape in one direction along the vertical direction, that is, a rectangular shape, a predetermined pitch, for example, not only at the four corners of the closing plate 11 but also on both sides in the short direction along the horizontal direction orthogonal to the vertical direction, for example. , The clamps 21 may be arranged at a pitch of 300 to 600 mm. Compared with the conventional fixing method (entire circumference welding), the number of welded points with the heat transfer tube block 13 is reduced, and the work period for attaching and detaching the closing plate 11 is shortened.
Further, the fixing pressure of the closing plate 11 can be finely adjusted by the tightening screw 22 of the clamp 21, and can be reused several times.

Further, in order to suppress a decrease in the tightening force of the clamp 21, the movable base 23 and the closing plate 11 may be welded (spot welded). In FIG. 12, the spot welded portion is indicated by reference numeral W3. Further, the thread of the tightening screw 22 may be crushed (thread crushing). As a result, the tightening screw 22 does not loosen, so that a decrease in the tightening force of the clamp 21 can be suppressed. When the screw thread is crushed, the used clamp 21 cannot be reused after removing the closing plate 11 and the clamp 21. In order to reuse the clamp 21, it is preferable to replace the tightening screw 22.

As shown in FIG. 13, the movable base 23 and the fixed base 24 are opposed to each other so that the tightening force is reduced due to the thermal expansion of the clamp 21 and the closing plate 11 does not shift or the mantis shrimp vise does not fall off. The cushion material 25 may be sandwiched between the closing plate 11 and the closing plate 11. The cushion material 25 is, for example, a material having elasticity up to the operating temperature (200 to 300 ° C. in this embodiment) such as mild steel, copper, and engineering plastic.

[Third Embodiment]
Next, the closing plate structure according to the third embodiment of the present invention will be described. The detailed description of the configuration and the action and effect overlapping with the first embodiment or the second embodiment will be omitted.
In the first and second embodiments described above, a plurality of closing plates 11 are arranged in the longitudinal direction along the vertical direction. The adjacent closing plates 11 may be arranged so that their smooth longitudinal end faces are abutted against each other, or in the present embodiment, the longitudinal end faces are provided with a meshing shape so as to be slightly free from each other. They may be joined with a gap that allows them to move.

When the closing plate 11 is made of a thick plate as in the first embodiment described above, warpage deformation is likely to occur due to a temperature difference between the front and back surfaces. Therefore, as shown in FIG. 14, the shapes of the end portions in the longitudinal direction along the vertical direction of the adjacent closing plates 11 are convex and concave, respectively, and the adjacent end portions are slightly free to move with each other. It has a stepped structure that is held together. That is, of the two adjacent closing plates 11, the convex portion 26 is formed at the longitudinal end portion of one closing plate 11, and the concave portion 27 is formed at the longitudinal end portion of the other closing plate 11. The convex portion 26 has a shape protruding in the longitudinal direction from the longitudinal end portion of the closing plate 11 at the central portion in the plate thickness direction of the closing plate 11, and the concave portion 27 is located at the central portion in the plate thickness direction of the closing plate 11. Therefore, the closing plate 11 has a shape recessed in the longitudinal direction from the end portion in the longitudinal direction.

Due to this structure, the longitudinal end of the closing plate 11 is adjacent to the other closing plate 11, and the longitudinal end of the closing plate 11 restrains the warp deformation in the vertical direction while allowing mutual thermal elongation in the longitudinal direction. Deformation (warp) that occurs mainly in the vertical direction of the longitudinal end of the closing plate 11 due to the difference in thermal elongation due to the temperature difference between the upper surface and the bottom surface in the direction, and further includes horizontal deformation if there is an in-plane temperature distribution. It is suppressed, the generation of a gap between the heat transfer tube block 13 and the closing plate 11 can be suppressed, and the amount of exhaust gas passing through this gap in a short pass can be reduced.

In a plate-shaped member such as the closing plate 11, it is known that the amount of deformation (warping amount) increases as the plate length in the longitudinal direction increases. Therefore, the plate length of the closing plate 11 is shortened. Warpage deformation may be suppressed. By using a thick plate as the closing plate 11, the amount of warpage deformation increases as the temperature difference between the front and back surfaces increases. Therefore, by shortening the plate length and combining the closing plate 11 with an uneven fitting structure on the end surface in the longitudinal direction, warpage deformation can be suppressed and the closing plates 11 can be displaced from each other. It is possible to prevent the occurrence of gaps.

The fitting structure of the closing plates 11 is not limited to the convex portion 26 and the concave portion 27, and may be a combination of L-shaped protruding portions.

Hereinafter, a gas turbine combined cycle (GTCC) power generation including an exhaust heat recovery steam generator (HRSG) to which the heat exchanger 10 according to the first to third embodiments of the present invention is applied as a low-pressure economizer 53. The system will be described.

As shown in FIG. 19, the gas turbine combined cycle power generation system 40 includes a gas turbine 41, an exhaust heat recovery boiler 42, a steam turbine 43, a condenser (condenser) 44, and a water supply circulation line (water supply means) 62. And have.

The gas turbine 41 sucks air from the atmosphere, compresses it with the compressor 45, and sends high-pressure air to the combustor 46. On the other hand, the fuel gas is supplied to the combustor 46, and the fuel is burned by the high-pressure air supplied from the compressor 45 to become a high-temperature, high-pressure gas. The high-temperature and high-pressure gas rotates the turbine 47 to rotationally drive the gas turbine 41. Further, the steam turbine 43 is rotationally driven by the steam (low pressure steam, high pressure steam) generated in the exhaust heat recovery boiler 42 to drive the compressor 45, and at least one of the rotational drive of the steam turbine 43 and the gas turbine 41. The generator 48 is rotationally driven to generate electric output and generate electricity.

Then, the exhaust gas (GT exhaust gas) generated by combustion in the gas turbine 41 is sent to the exhaust heat recovery boiler 42.

The exhaust heat recovery boiler 42 includes a duct 12, a high-pressure superheater 49, a high-pressure economizer 50, a high-pressure economizer 51, a low-pressure economizer 52, a low-pressure economizer 53, and the like. The high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure economizer 52, and the low-pressure economizer 53 are placed in the duct 12 from the front flow side to the back flow side along the gas flow direction of the exhaust gas. They are arranged in this order. The heat exchanger 10 described above is a low-pressure economizer 53 arranged at the top of a plurality of heat exchangers arranged in the duct 12 of the exhaust heat recovery boiler 42.

The duct 12 has a gas inlet portion 54 into which the exhaust gas from the gas turbine 41 is introduced, and an outlet damper 55 leading to the chimney. In the example shown in FIG. 19, the flow path of the exhaust gas formed in the duct 12 extends in the vertical vertical direction, and is formed so that the exhaust gas flows from the vertical lower side to the vertical upper side. The outlet damper 55 is connected to the chimney, and the exhaust gas discharged from the outlet damper 55 is released from the chimney to the atmosphere.

The high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure economizer 52, and the low-pressure economizer 53 are housed in the duct 12. The high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure evaporator 52, and the low-pressure economizer 53 are composed of a plurality of heat transfer tubes 30. Further, in the example of FIG. 19, the high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure economizer 52, and the low-pressure economizer 53 are arranged in the duct 12 so that their longitudinal directions are horizontal. Has been done. The high-pressure superheater 49, the high-pressure evaporator 50, the high-pressure economizer 51, the low-pressure economizer 52, and the low-pressure economizer 53 are provided so as to intersect the exhaust gas flow path of the exhaust gas, and flow from vertically downward to vertically upward. It is arranged so that it is exposed to exhaust gas.

The low-pressure steam and high-pressure steam discharged from the exhaust heat recovery boiler 42 are supplied to the steam turbine 43. The steam turbine 43 is rotationally driven by the low-pressure steam and high-pressure steam generated by the exhaust heat recovery boiler 42. The low-pressure steam and high-pressure steam used as the drive source of the steam turbine 43 are discharged to the water supply circulation line 62 and sent to the condenser 44. The condenser 44 condenses the low-pressure steam and high-pressure steam used as the drive source of the steam turbine 43 to condense the water. The condensate discharged from the condensate 44 is supplied by the pump 56 to the exhaust heat recovery boiler 42 via the water supply circulation line 62 as water supply.

The water supplied to the exhaust heat recovery boiler 42 is sent to the low-pressure economizer 53 and heated by exchanging heat with the exhaust gas, heated in the low-pressure evaporator 52, and sent to the low-pressure drum 57. The liquid is separated. The low-pressure steam separated by the low-pressure drum 57 is discharged from the low-pressure drum 57 and supplied to the low-pressure steam turbine 58 of the steam turbine 43 to rotationally drive the low-pressure steam turbine 58.

Further, the water supply is pressurized by the pump 59, then sent to the high-pressure economizer 51 to be heated, and then heated in the high-pressure evaporator 50 and sent to the high-pressure drum 60 for gas-liquid separation. The high-pressure steam separated by the high-pressure drum 60 is discharged from the high-pressure drum 60, heated by the high-pressure superheater 49, and then supplied to the high-pressure steam turbine 61 of the steam turbine 43 to rotationally drive the high-pressure steam turbine 61. .. The steam discharged from the high-pressure steam turbine 61 is sent into the low-pressure evaporator 52 by a steam pipe (not shown), reheated, gas-liquid separated by the low-pressure drum 57, and supplied to the low-pressure steam turbine 58 of the steam turbine 43. To.

As described above, in the gas turbine combined cycle power generation system 40, the turbine 47 of the gas turbine 41 is rotated to drive the gas turbine 41, and the low pressure steam turbine 58 and the high pressure of the steam turbine 43 are used by using low pressure steam and high pressure steam. The steam turbine 61 is rotated, the steam turbine 43 is rotationally driven, and the generator 48 is rotationally driven to generate power.

Further, the low-pressure steam and the high-pressure steam are supplied to the steam turbine 43, then supplied to the condenser 44 to be condensed water, and are circulated as water supply to the exhaust heat recovery boiler 42. The low-pressure steam and high-pressure steam generated by the exhaust heat recovery boiler 42 are supplied to the steam turbine 43 to rotate the steam turbine 43, and the generator 48 is rotated by at least one of the rotary drive of the steam turbine 43 and the gas turbine 41. Drive to generate electricity.

As described above, according to the first to third embodiments of the present invention, by attaching or detaching the closing plate 11 to the gap between the heat transfer tube block 13 and the heat transfer tube block 13, the GT exhaust gas due to the change in the outside air temperature, that is, the air density can be obtained. It can absorb fluctuations in flow rate and pressure of exhaust gas, and even when the pressure loss of exhaust gas in the exhaust heat recovery boiler increases and the pressure of GT exhaust gas rises, it is possible to avoid the state where the pressure of GT exhaust gas exceeds a predetermined pressure value. .. As a result, the operation can be continued without stopping the GT.

Further, according to the first to third embodiments of the present invention, the installation work period for attaching and detaching the closing plate 11 is improved as compared with the case where the entire circumference of the closing plate 11 is welded, so that the installation work period is shortened. Is possible.

10: Heat exchanger 11: Closing plate 12: Duct 13: Heat transfer tube block 14: Fixed plate 15: Guide hardware 15a: Horizontal part 15b: Vertical part 16: First auxiliary plate 17: Handle part 18: Second auxiliary plate 19 : Fixing tool 20: Stopper 20A: Lower stopper 20B: Upper stopper 21: Clamp 22: Tightening screw 23: Movable base 24: Fixing base 25: Cushion material 26: Convex part 27: Recessed part 30: Heat transfer tube 40: Gas turbine combined Cycle power generation system 41: Gas turbine 42: Exhaust heat recovery boiler 43: Steam turbine 44: Water recovery device 45: Compressor 46: Combustor 47: Turbine 48: Generator 49: High pressure overheater 50: High pressure evaporator 51: High pressure Economizer 52: Low pressure evaporator 53: Low pressure coal saver 54: Gas inlet 55: Outlet damper 56: Pump 57: Low pressure drum 58: Low pressure steam turbine 59: Pump 60: High pressure drum 61: High pressure steam turbine 62: Water supply Circulation line

Claims (2)

A heat transfer tube block with multiple heat transfer tubes and
It is installed at the upper end of the gap formed between the adjacent heat transfer tube blocks in the vertical direction so that the direction along the longitudinal direction of the heat transfer tube is the longitudinal direction, and the flow of gas trying to pass through the gap is allowed to flow. With a blocking plate that hinders
It is a method of adjusting the gas flow of a boiler equipped with
When the outside air temperature is lower than a predetermined threshold value, a step of removing the closing plate,
Wherein when the outside air temperature is above the predetermined threshold, Rubo Ira method for a gas flow adjustment having a and attaching the closing plate. A heat transfer tube block with multiple heat transfer tubes and
It is installed at the upper end of the gap formed between the adjacent heat transfer tube blocks in the vertical direction so that the direction along the longitudinal direction of the heat transfer tube is the longitudinal direction, and the flow of gas trying to pass through the gap is allowed to flow. With a blocking plate that hinders
It is a method of adjusting the gas flow of a boiler equipped with
When the pressure of the gas supplied to the heat transfer tube block is higher than a predetermined threshold value, the step of removing the closing plate and the step of removing the closing plate.
When the pressure of the gas supplied to the heat transfer thermal tubes block is below the predetermined threshold, Rubo Ira method for a gas flow adjustment having a and attaching the closing plate.

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