JP2019120476A - Marine boiler - Google Patents

Abstract

To improve the increase rate of the operation load of a marine boiler while protecting the stream turbine wheel chamber by reducing the temperature difference between the superheated steam by the supper heater and the reheat steam by the reheater.SOLUTION: A marine boiler 10 comprises: a main furnace 11; a main burner 13 for burning fuel in the main furnace 11; a supper heater 16 and an evaporator 15 through which combustion gas G created by the burning of the main burner 13 passes; and a first reheater 17 disposed on the upstream of combustion gas G flow of the supper heater 16 and the evaporator 15. By this configuration, since steam generation by the first reheater 17 can be performed on the upstream side of the flow of the combustion gas G, that is, the region where the gas temperature is relatively higher than the superheater 16 and the evaporator 15, it is possible to quickly reheat the steam at the first reheater 17.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a marine boiler.

  DESCRIPTION OF RELATED ART Conventionally, the technique regarding the reheat boiler provided with the reheat furnace and the reheater as a marine boiler is known. For example, in Patent Document 1, a reheating furnace that generates reheat gas by combustion of a reheat burner on the downstream side of the combustion gas than the superheater and the evaporation tube group is disposed on the upper side of the reheating furnace. Discloses a structure of a reheat boiler provided with a reheater.

JP, 2010-71513, A

  In the reheat boiler described in Patent Document 1, the reheater is disposed downstream of the superheater and the evaporation tube group, that is, in a region where the temperature of the combustion gas is relatively low. Therefore, when increasing the operating load of the boiler from low load to high load, the temperature rise of the superheated steam by the superheater disposed in the vicinity of the main furnace where most of the fuel necessary for the boiler is charged is increased again. The ability to follow up the temperature rise of reheated steam by the heater becomes low. That is, the temperature difference between the superheated steam and the reheated steam tends to be large. As a result, there may be a problem such as thermal deformation of the casing of the steam turbine casing due to the temperature difference between the overheated steam and the reheated steam. In addition, if the rate of increase in the load on the boiler is limited in order to reduce the temperature difference between the overheated steam and the reheated steam by the reheater, the efficiency of the marine boiler as a marine propulsion engine as a moving body is increased. Operation may be hampered.

  The present invention has been made in view of the above, and reduces the temperature difference between the superheated steam by the superheater and the reheated steam by the reheater to protect the steam turbine casing and operate the marine boiler The purpose is to improve the rate of increase in load.

  In order to solve the problems described above and achieve the object, the present invention provides a furnace, a burner for burning fuel in the furnace, and a superheater and an evaporator through which the combustion gas generated by the combustion of the burner passes. And a reheater disposed upstream of the flow of the combustion gas with respect to the superheater and the evaporator.

  With this configuration, the reheater can generate reheated steam upstream of the flow of the combustion gas, that is, in a region where the gas temperature is relatively higher than that of the superheater and the evaporator, so that reheating can be performed quickly. It is possible to reheat the steam. As a result, when the operating load of the marine boiler is increased from a low load to a high load, the temperature rise of the superheated steam by the superheater can be favorably followed by the temperature rise of the reheat steam by the reheater. Therefore, according to the marine boiler of the present invention, the temperature difference between the superheated steam by the superheater and the reheated steam by the reheater is reduced to protect the casing of the steam turbine, and the operating load of the marine boiler is increased. It is possible to improve the rate.

  Preferably, the reheater is attached to a wall forming the furnace and is positioned to the side of the flame formed by the burner.

  With this configuration, the reheater can be easily disposed in the high gas temperature region.

  Preferably, the reheater is provided within a range separated from the tip end of the burner by 0.5 times the maximum length of the flame in the longitudinal direction of the flame.

  According to this configuration, it is possible to generate reheat steam by the reheater in a region where the gas temperature is relatively high, even when the flame formed by the burner is small, that is, even during low load operation of the marine boiler. As a result, when the operating load of the marine boiler is increased from a low load, the temperature rise of the superheated steam by the superheater can be made to follow the temperature rise of the reheat steam by the reheater better. In addition, when the flame formed by the burner is large, that is, at the time of high load operation of the marine boiler, the reheater is disposed at a relatively distant position from the region where the temperature is high near the flame tip. Excessive heat transfer can be suppressed.

  In the marine boiler according to the present invention, a reheat furnace disposed downstream of the superheater and the evaporator, a reheat burner for burning fuel in the reheat furnace, the burner, and the reheat burner It is preferable to further include a second reheater through which the combustion gas generated by the combustion of the thermal burner passes and the vapor reheated by the reheater flows.

  According to this configuration, the combustion of the reheating burner provided in the reheating furnace is adjusted, and the second reheater disposed in a region where the gas temperature is relatively low brings the steam from the reheater to an appropriate temperature. It can be adjusted and supplied to equipment driven by the marine boiler as a power source. That is, the temperature control of the reheated steam can be finely adjusted.

  Moreover, it is preferable that the marine boiler concerning this invention is further provided with the overheat reduction device which cools the steam reheated by the said reheater.

  According to this configuration, it is possible to finely adjust the temperature of the reheated steam reheated by the reheater using the overheat reducer.

  Preferably, a plurality of the burners are provided in the furnace, and the reheater is attached to at least one of the wall portions forming the furnace which is close to the burner burning at the minimum load. .

  According to this configuration, when the operating load of the marine boiler is increased from the low load, the temperature rise of the superheated steam by the superheater can be favorably followed by the temperature rise of the reheated steam by the reheater.

FIG. 1 is a schematic view of a marine boiler according to the present embodiment. FIG. 2 is a cross-sectional view taken along the line A-A of FIG. FIG. 3 is a cross-sectional view showing a modification of the marine boiler according to the present embodiment.

  Hereinafter, an embodiment of a marine boiler according to the present invention will be described in detail based on the drawings. The present invention is not limited by this embodiment.

  The marine boiler according to the present embodiment is mounted on a ship and will be described as a main machine boiler serving as a power source at the time of navigation. However, the marine boiler is not limited to the main machine boiler, and may be, for example, an auxiliary boiler that generates miscellaneous steam for operating various devices mounted on a ship, or a boiler that generates steam serving as a driving source of a power plant. It can be used.

  FIG. 1 is a schematic view of a marine boiler according to the present embodiment, and FIG. 2 is a cross-sectional view taken along the line A-A of FIG. As shown in FIG. 1, the marine boiler 10 according to the present embodiment includes a main furnace (furnace) 11, a reheating furnace 12, a main burner (burner) 13, a reheating burner 14, and an evaporator 15. A superheater 16, a first reheater (reheater) 17, and a second reheater (second reheater) 18 are provided.

  The main furnace 11 and the reheating furnace 12 are formed in a hollow box-shaped combustion container 20. The combustion container 20 has a ceiling 20a, a bottom 20b, a front wall 20c (see FIG. 2), a rear wall 20d (see FIG. 2), and a pair of side walls 20e and 20f. The ceiling part 20a is formed with a flue 21 in which the gas outlet 22 is provided. The bottom 20b is provided to face the ceiling 20a. The front wall 20c, the rear wall 20d, and the pair of side walls 20e and 20f extend between the ceiling 20a and the bottom 20b.

  The main furnace 11 is divided by a ceiling 20a, a bottom 20b, a front wall 20c, a rear wall 20d, a side wall 20e and a front bank tube 28 described later. The main furnace 11 is provided with a main burner 13 and a first reheater 17.

  The reheating furnace 12 is partitioned by a ceiling 20 a, a bottom 20 b, a front wall 20 c, a rear wall 20 d, a side wall 20 f, and an evaporator 15. The reheating furnace 12 is provided with a reheating burner 14. In addition, the reheating furnace 12 is connected to the flue 21 at the top and communicates with the gas outlet 22.

  The main burner 13 is provided at a position apart from the flue 21 on the side wall portion 20 e side of the ceiling portion 20 a in the main furnace 11. The main burner 13 can burn the fuel gas by injecting the fuel gas into the main furnace 11 to form a flame F1 directed to the bottom 20b side.

  The reheating burner 14 is provided in the reheating furnace 12 at a position apart from the flue 21 of the front wall portion 20 c. The reheat burner 14 burns the fuel gas by injecting the fuel gas into the reheat furnace 12, and can form a flame F2 directed to the rear wall 20d side as shown in FIG.

  The evaporator 15 is constituted by a group of evaporation pipes in which a plurality of evaporation pipes 25 are bundled. The plurality of evaporation tubes 25 are disposed in the combustion vessel 20 along the fuel gas ejection direction of the main burner 13. The plurality of evaporation tubes 25 are connected to a water drum 26 whose lower end is supported by the bottom 20 b and connected to a steam drum 27 whose upper end is supported by the ceiling 20 a. Moreover, the front bank tube 28 is arrange | positioned by the evaporator 15 being arrange | positioned by bending the one part evaporation pipe 25 at the side wall part 20e side.

  The superheater 16 is constituted by a heat transfer tube group in which a plurality of heat transfer tubes 30 are bundled. The plurality of heat transfer tubes 30 are disposed in the combustion vessel 20 along the fuel gas ejection direction of the main burner 13. One end of the plurality of heat transfer tubes 30 is connected to the inlet header 31 through the bottom 20b, and the other end is connected to the outlet header 32 through the bottom 20b. The inlet header 31 and the outlet header 32 are disposed outside the combustion vessel 20. The superheater 16 is disposed between the plurality of evaporation tubes 25 and the front bank tube 28.

  The first reheater 17 is provided in the main furnace 11. The first reheater 17 is constituted by a heat transfer tube group in which a plurality of heat transfer tubes (not shown) are bundled. The heat transfer tube group of the first reheater 17 is connected at its lower end to a steam pipe 51 through which the steam extracted in the middle of the expansion process of a steam turbine (not shown) driven by steam from the marine boiler 10 flows. Further, the heat transfer tube group of the first reheater 17 is connected to the steam pipe 52 at the upper end.

  In the present embodiment, as shown in FIG. 2, the first reheaters 17 are respectively provided on the front wall 20 c, the rear wall 20 d, and the side wall 20 e that form the main furnace 11. That is, the first reheater 17 is disposed on the wall surface facing the flame forming area where the flame of the main furnace 11 is formed. Further, as shown in FIG. 1, the first reheater 17 is located on the side of the flame F1 formed by the main burner 13. That is, the first reheater 17 is attached to the front wall 20c, the rear wall 20d and the side wall 20e so as to surround the flame F1. More specifically, the first reheater 17 has a maximum length of the flame F1 from the tip 13a of the main burner 13 in the longitudinal direction of the flame F1 (the fuel gas ejection direction of the main burner 13: the vertical direction in FIG. 1). It is provided in a range separated by a distance L of 0.5 times the Lmax. The maximum length Lmax of the flame F1 is the length of the flame F1 formed by the main burner 13 during rated load operation of the marine boiler 10. Also, the maximum length of the flame F1 is the length of the flame planned at design time.

  The second reheater 18 is provided in the flue 21 on the side of the reheating furnace 12. The second reheater 18 is constituted by a heat transfer tube group in which a plurality of heat transfer tubes (not shown) are bundled. The heat transfer tube group of the second reheater 18 is connected to the steam pipe 52 at the upper end. Further, the heat transfer tube group of the second reheater 18 is connected at a lower end portion to a steam piping 53 which allows the reheated steam to flow into a steam turbine (not shown). An economizer 19 as a heat exchanger is provided closer to the gas outlet 22 than the second reheater 18 of the flue 21.

  In the present embodiment, as shown in FIG. 1, the steam piping 52 connecting the first reheater 17 and the second reheater 18 is provided with the overheat reducer 40 in the middle. The overheat reducer 40 cools the steam flowing in the steam pipe 52 to adjust the temperature. The overheat reduction device 40 is, for example, a water injection device capable of injecting cooling water to the steam flowing in the steam pipe 52. In addition, the overheat reduction device 40 may be anything as long as it can cool the steam flowing in the steam piping 52 and adjust the temperature.

  As shown in FIG. 1, the marine boiler 10 is directed from the main burner 13 to the gas outlet 22, the main furnace 11, the first reheater 17 in the main furnace 11, the front bank tube 28, the superheater 16, and the evaporator. 15, the reheating furnace 12, the second reheater 18, and the economizer 19 are disposed in this order. The main burner 13 injects the fuel gas to the main furnace 11 and burns it, thereby forming a flame F1 and generating the combustion gas G. The generated combustion gas G flows from the side wall portion 20 e side of the main furnace 11 to the side wall portion 20 f side. At this time, the combustion gas G sequentially passes through the area in which the first reheater 17 is disposed, the area in which the front bank tube 28 is disposed, the area in which the superheater 16 is disposed, and the area in which the evaporator 15 is disposed. Then, the reheating furnace 12 is reached.

  The first reheater 17 is disposed on the upstream side of the flow of the combustion gas G than the superheater 16 and the evaporator 15, that is, in a region where the gas temperature in the combustion vessel 20 is relatively high. In the first reheater 17, water or steam used in a steam turbine (not shown) introduced through the steam piping 51 flows in each heat transfer pipe. The first reheater 17 recovers the heat of the combustion gas G by heat exchange between the combustion gas G and water or steam, thereby raising the temperature of water or steam and decreasing the temperature of the combustion gas G.

  The front bank tube 28 is disposed on the main burner 13 side in the combustion vessel 20, that is, in the region where the temperature in the combustion vessel 20 is high. The front bank tube 28 is connected to the steam drum 27 and the header 33, and water and steam flow inside. The front bank tube 28 recovers the heat of the combustion gas G by heat exchange between the combustion gas G and water or steam when water or steam flows from the header 33 through the evaporation tubes 25 to the steam drum 27. , Raise the temperature of water and steam, and lower the temperature of combustion gas G.

  The superheater 16 passes the combustion gas G which has passed through the area where the front bank tube 28 is disposed. In the superheater 16, the inlet header 31 and the outlet header 32 are respectively connected to the ends of the plurality of heat transfer tubes 30, and water and steam flow in the respective heat transfer tubes 30. The superheater 16 recovers the heat of the combustion gas G by heat exchange between the combustion gas G and water or steam when water or steam flows from the inlet header 31 through the heat transfer pipes 30 to the outlet header 32. , Raise the temperature of water and steam, and lower the temperature of combustion gas G.

  The evaporator 15 is disposed closer to the gas outlet 22 than the superheater 16 in the combustion vessel 20. The evaporator 15 passes the combustion gas G which has passed through the area where the superheater 16 is disposed. The evaporator 15 has a water drum 26 and a steam drum 27 respectively connected to the ends of the plurality of evaporation tubes 25, and water and steam flow in the evaporation tubes 25. The evaporator 15 recovers the heat of the combustion gas G by heat exchange between the combustion gas G and water or steam when water or steam flows from the water drum 26 through the evaporation pipes 25 to the steam drum 27. , Raise the temperature of water and steam, and lower the temperature of combustion gas G.

  Heat is recovered from the combustion gas G that has passed through the evaporator 15 to lower its temperature and reach the reheating furnace 12. The reheating furnace 12 burns the fuel gas by the reheating burner 14 to generate the combustion gas G again. The combustion gas G generated in the reheating furnace 12 and the combustion gas G passing through the evaporator 15 flow to the flue 21 and the region where the second reheater 18 is disposed, the region where the economizer 19 is disposed The gas passes sequentially to the gas outlet 22.

  In the second reheater 18, water and steam from the first reheater 17 introduced through the steam pipe 52 flow in each heat transfer pipe. The second reheater 18 raises the temperature of the water or steam and lowers the temperature of the combustion gas G by recovering the heat of the combustion gas G by heat exchange between the combustion gas G and water or steam. In addition, water flows inside the economizer 19, and the heat of the combustion gas G is recovered by heat exchange between the combustion gas G and the water to raise the temperature of the water, and the temperature of the combustion gas G is increased. Reduce. Heat is recovered from the combustion gas G that has passed through the second reheater 18 and the economizer 19, the temperature is reduced, and the exhaust gas is discharged from the gas outlet 22 to the outside.

  The marine boiler 10 burns the fuel gas by the main burner 13 to generate the combustion gas G, and exchanges heat between the combustion gas G and water or steam by the front bank tube 28 and the evaporator 15 to raise the temperature of water. The steam is stored in the steam drum 27. Then, the steam of the steam drum 27 is superheated by the superheater 16 and becomes superheated steam. The marine boiler 10 drives and rotates a propeller shaft, which is a propeller, by supplying the superheated steam to a steam turbine (not shown), and generates electric power with a generator using a part of the steam.

  Further, the marine boiler 10 reheats the steam used in the steam turbine (not shown) by the first reheater 17 and the second reheater 18 to generate steam (reheat steam), and Supply to the steam turbine again. Further, the marine boiler 10 includes the combustion of the overheat reducer 40 provided in the steam pipe 52 connecting the first reheater 17 and the second reheater 18 and the reheat burner 14 provided in the reheat furnace 12. Adjust the steam to be reheated to a suitable temperature by controlling.

  As described above, the marine boiler 10 according to the present embodiment includes the main furnace 11, the main burner 13 for burning the fuel in the main furnace 11, and the overheat through which the combustion gas G generated by the combustion of the main burner 13 passes. And a first reheater 17 disposed upstream of the flow of the combustion gas G than the superheater 16 and the evaporator 15.

  With this configuration, the reheat steam can be generated by the first reheater 17 on the upstream side of the flow of the combustion gas G, that is, the region where the gas temperature is relatively higher than the superheater 16 and the evaporator 15. In the first reheater 17, it is possible to quickly reheat the steam. As a result, when the operating load of the marine boiler 10 is increased from a low load to a high load, the temperature rise of the superheated steam by the superheater 16 is made to follow the temperature rise of the reheated steam by the first reheater 17 well. Can. Therefore, according to the marine boiler 10 according to the present embodiment, the temperature difference between the superheated steam by the superheater 16 and the reheated steam by the first reheater 17 is reduced, and protection of the steam turbine casing (not shown) is achieved. The increase rate of the operation load of the marine boiler 10 can be improved.

  In addition, by arranging the first reheater 17 in a region where the gas temperature in the combustion container 20 is relatively high, the heat transfer from the combustion gas G to the first reheater 17 is favorably performed. One reheater 17 can also be miniaturized.

  The first reheater 17 is attached to the front wall 20c, the rear wall 20d, and the side wall 20e that form the main furnace 11, and is positioned on the side of the flame F1 that the main burner 13 forms.

  According to this configuration, the first reheater 17 can be easily disposed in the region where the gas temperature is high.

  Further, the first reheater 17 is provided in a range separated by a distance L of 0.5 times the maximum length Lmax of the flame F1 from the tip 13a of the main burner 13 in the longitudinal direction of the flame F1. .

  With this configuration, the reheat steam is generated by the first reheater 17 in a region where the gas temperature is relatively high even when the flame F1 formed by the main burner 13 is small, that is, even during low load operation of the marine boiler 10. Can. As a result, when the operating load of the marine boiler 10 is increased from the low load, the temperature rise of the reheated steam by the first reheater 17 can be made to follow the temperature rise of the superheated steam by the superheater 16 better. it can. In addition, when the flame F1 formed by the main burner 13 is large, that is, during high load operation of the marine boiler 10, the first reheater 17 is disposed at a relatively distant position from the region where the temperature near the tip of the flame F1 is high. Thus, excessive heat transfer to the first reheater 17 can be suppressed.

  Further, the marine boiler 10 according to the present embodiment includes the reheating furnace 12 disposed on the downstream side of the superheater 16 and the evaporator 15, the reheating burner 14 for burning fuel in the reheating furnace 12, and the main The second reheater 18 is further provided, through which the combustion gas G generated by the combustion of the burner 13 and the reheat burner 14 passes and the vapor from the first reheater 17 flows.

  According to this configuration, the steam from the first reheater 17 is controlled by the second reheater 18 which controls the combustion of the reheat burner 14 provided in the reheat furnace 12 and is disposed in a region where the gas temperature is relatively low. Can be adjusted to an appropriate temperature, and can be supplied again to an apparatus (in the present embodiment, a steam turbine not shown) driven by the marine boiler 10 as a power source. That is, the temperature control of the reheated steam can be finely adjusted.

  In addition, the marine boiler 10 according to the present embodiment further includes an overheat reducer 40 that cools the steam reheated by the first reheater 17.

  According to this configuration, the temperature reducing device 40 can be used to finely adjust the temperature of the reheated steam in the first reheater.

  The first reheater 17 is not limited to the mounting position shown in the present embodiment, and may be provided at any position as long as it is disposed upstream of the flow of the combustion gas G than the superheater 16 and the evaporator 15 It may be done. For example, the first reheater 17 may be attached to any one or any two of the front wall 20c, the rear wall 20d, and the side wall 20e. Further, the first reheater 17 is provided at a position separated from the tip 13a of the main burner 13 in the longitudinal direction of the flame F1 by a distance L which is 0.5 times the maximum length Lmax of the flame F1. May be

  FIG. 3 is a cross-sectional view showing a modification of the marine boiler according to the present embodiment. As illustrated, the marine boiler 100 according to the modification is provided with a plurality (three in the present embodiment) of main burners 131, 132, 133 in the main furnace 11. Here, when the operation load of the marine boiler 100 is the minimum load, combustion is performed by the main burner 132 located at the center in the figure. In the marine boiler 100 according to the modification, the first reheater 17 is attached to the side wall portion 20e as illustrated. That is, among the front wall portion 20c, the rear wall portion 20d, and the side wall portion 20e which form the main furnace 11, at least, it is attached to the one close to the main burner 132 which burns with the minimum load. With this configuration, when the operating load of the marine boiler 10 is increased from a low load, the temperature rise of the superheated steam by the superheater 16 can be favorably followed by the temperature rise of the steam by the first reheater 17. In addition, you may attach the 1st reheater 17 to all the front wall part 20c, the rear wall part 20d, and the side wall part 20e similarly to the marine boiler 10 shown in FIG.

  In the present embodiment, the marine boilers 10, 100 are provided with the reheating furnace 12, the reheating burner 14, and the second reheating device 18. However, the reheating furnace 12, the reheating burner 14, the second reheating furnace The heater 18 may be omitted from the marine boilers 10, 100, and the steam from the first reheater 17 may be supplied to a steam turbine (not shown). Also, the economizer 19 may be omitted from the marine boilers 10, 100. In addition, the overheat reduction device 40 may be omitted from the marine boiler 10, 100.

10, 100 Marine boiler 11 Main furnace 12 Reheating furnace 13, 131, 132, 133 Main burner 13a Tip 14 Reheating burner 15 Evaporator 16 Superheater 17 First reheater 18 Second reheater 19 Economizer 20 Combustion vessel 20a ceiling 20b bottom 20c front wall 20d back wall 20e side wall 20f side wall 21 flue 22 gas outlet 25 evaporation tube 26 water drum 27 steam drum 28 front bank tube 30 heat transfer tube 31 inlet header 32 outlet header 33 header 40 Overheat reducer 51, 52, 53 Steam piping F1, F2 flame G combustion gas

Claims (6)

A furnace and
A burner for burning fuel in the furnace;
A superheater and an evaporator through which the combustion gas generated by the combustion of the burner passes;
A reheater disposed upstream of the flow of the combustion gas than the superheater and the evaporator;
A marine boiler characterized by comprising:   The marine boiler according to claim 1, wherein the reheater is attached to a wall forming the furnace, and is positioned to the side of a flame formed by the burner.   3. The apparatus according to claim 2, wherein the reheater is provided in a range separated from the tip of the burner by 0.5 times the maximum length of the flame in the longitudinal direction of the flame. Marine boiler as described in. A reheating furnace disposed downstream of the superheater and the evaporator;
A reheat burner for burning fuel in the reheat furnace;
A second reheater through which the combustion gas generated by the combustion of the burner and the reheat burner passes and the steam reheated by the reheater flows;
The marine boiler according to any one of claims 1 to 3, further comprising:   The marine boiler according to any one of claims 1 to 4, further comprising a desuperheater for cooling the steam reheated by the reheater. A plurality of the burners are provided in the furnace,
The said reheater is attached to the thing of the wall part which forms the said furnace at least near the said burner which burns with the minimum load, The any one of the Claims 1-5 characterized by the above-mentioned. Marine boiler as described in.

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