JP2012167859A - Marine boiler - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a marine boiler configured to be capable of increasing the temperature of superheated steam to thereby improve the efficiency.SOLUTION: A marine boiler 5 is configured so that the combustion gas generated by the combustion of a main burner 33 can flow from a furnace 31 through a superheater 37 and an evaporation pipe bundle 39, wherein the superheater 37 is constructed of a primary superheater pipe 59 disposed on the side of a furnace 31 and a secondary superheater pipe 61 disposed on the side of an evaporation pipe bundle 39, the primary superheater pipe 59 with the secondary superheater pipe 61 connected with each other in series.

Description

  The present invention relates to a marine boiler mounted on a ship.

2. Description of the Related Art Conventionally, a marine boiler mounted on a marine vessel is given priority to a compact structure because it has a larger installation space than a land boiler used in a power plant or the like.
For this reason, for example, as shown in Patent Document 1, the superheater is disposed on the upstream side of the evaporator tube group, and superheats steam by using radiant heat from the furnace in addition to convection heat. . This superheater is composed of one loop of superheater tubes.

JP 2009-97802 A

  By the way, in the superheater comprised by the one loop of a superheater pipe | tube as shown by patent document 1, the expansion of a heat transfer area is restrict | limited. For this reason, in order to obtain higher temperature superheated steam with the aim of improving efficiency, it is necessary to give a large amount of heat to the superheater tube. When the amount of heat supplied to the superheater pipe is increased, the surface temperature of the superheater pipe rises, so there is a limit to increasing the temperature of the superheated steam due to material limitations.

  In view of such circumstances, an object of the present invention is to provide a marine boiler capable of increasing the temperature of superheated steam and improving efficiency.

In order to solve the above problems, the present invention employs the following means.
That is, one aspect of the present invention is a marine boiler configured such that combustion gas generated by combustion of a burner flows from a furnace through a superheater and an evaporation tube group, and the superheater A primary loop of the superheater pipe arranged on the side and a secondary loop of the superheater pipe arranged on the evaporation pipe group side, and the primary loop and the secondary loop are connected in series. It is a marine boiler.

According to this aspect, the combustion gas generated by the burner combustion flows from the furnace through the superheater and the evaporator tube group. At this time, since the superheater is close to the furnace, it is heated by the convection heat and radiant heat of the combustion gas, so that it can be heated to a high temperature.
In this aspect, the superheater is composed of a primary loop of the superheater pipe disposed on the furnace side and a secondary loop of the superheater pipe disposed on the evaporation tube group side. The combustion gas passes through the secondary loop of the superheater tube following the primary loop of the superheater tube. Since the primary and secondary loops are connected in series, the steam will be superheated while passing through the primary and secondary loops.
Thus, since the steam is superheated through the primary loop and the secondary loop, the heat transfer area of the superheater tube can be made larger than that of the conventional one loop. For this reason, the temperature of superheated steam can be increased and the efficiency of a marine boiler can be improved.

  In the above aspect, a front bank tube through which water passes may be disposed on the furnace side of the superheater.

  If it does in this way, a part of calorie | heat amount of the combustion gas from a furnace will be absorbed by a front bank tube. In addition, a part of the radiant heat from the furnace is blocked by the front bank tube. Thereby, the excessive heating with respect to the superheater pipe | tube of a superheater, especially the superheater pipe | tube of a furnace side can be suppressed, and it can suppress that the surface temperature of a superheater pipe | tube becomes high temperature and a thinning trouble generate | occur | produces.

  In the above configuration, the front bank tubes may be arranged in multiple rows.

  If it does in this way, the calorie | heat amount and radiant heat amount of the combustion gas which act on a superheater pipe | tube can further be suppressed, and it can suppress that the surface temperature of a superheater pipe | tube becomes high temperature and a thinning trouble generate | occur | produces.

  In the aspect, in the superheater, steam may flow from the primary loop to the secondary loop.

If it does in this way, since the low-temperature steam before superheating passes through the superheater pipe by the side of a furnace, this steam can cool a superheater pipe.
Accordingly, excessive heating of the superheater tube on the furnace side can be suppressed, and the occurrence of a thinning trouble due to the surface temperature of the superheater tube becoming high can be suppressed.

  In the above aspect, in the superheater, steam may flow from the secondary loop to the primary loop.

In this way, the steam flow and the combustion gas flow in the superheater have a countercurrent relationship, so that a large temperature difference between the combustion gas and the steam can be obtained in the entire flow direction, and the heat exchange efficiency can be improved. Can be improved.
Thereby, for example, even if the heat transfer area of the superheater tube on the furnace side is reduced, a predetermined high-temperature superheated steam can be obtained, excessive heating of the superheater tube on the furnace side can be suppressed, and the superheater tube It can suppress that surface temperature becomes high temperature and a thinning trouble generate | occur | produces. Therefore, the boiler can be made more compact even under the same steam condition.

  According to the present invention, the superheater is composed of a primary loop of the superheater pipe disposed on the furnace side and a secondary loop of the superheater pipe disposed on the evaporator tube group side. Since the next loop is connected in series, the temperature of the superheated steam can be increased, and the heat exchange efficiency of the marine boiler can be improved.

It is a mimetic diagram explaining a schematic structure of a marine propulsion plant using a marine boiler concerning a first embodiment of the present invention. It is a mimetic diagram explaining a schematic structure of a marine boiler concerning a second embodiment of the present invention. It is a graph which shows the temperature change of the combustion gas and steam in a superheater.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[First embodiment]
A marine boiler according to a first embodiment of the present invention will be described with reference to FIG.
FIG. 1 is a schematic diagram illustrating a schematic configuration of a marine propulsion plant using the marine boiler according to the present embodiment.

The marine propulsion plant 1 is provided with a propulsion turbine 3, a marine boiler 5, and a propeller 7 as a propulsion device.
The propulsion turbine 3 includes a high pressure turbine 9, an intermediate pressure turbine 11, a low pressure turbine 13, and a reverse turbine 15.
The high-pressure turbine 9 and the intermediate-pressure turbine 11 are connected via a single rotating shaft 17.
The low pressure turbine 13 and the reverse turbine 15 are connected via a single rotating shaft 21. The rotating shaft 17 and the rotating shaft 21 are connected to a speed reducer 23. A propeller 7 is connected to the speed reducer 23 via a propeller shaft 25. A shaft generator 19 is attached to the propeller shaft 25.

The marine boiler 5 is provided with a main furnace 27 and a reheating furnace 29. The main furnace 27 includes a hollow furnace 31 having a substantially rectangular parallelepiped shape, a main burner (burner) 33 installed on the top of the furnace 31, a front bank tube 35 through which water passes, a superheater 37, and an evaporation tube A group 39, a water drum 41, and a steam drum 43 are provided.
A wall tube 45 through which water passes is disposed on the wall portion of the furnace 31. The main burner 33 is supplied with fuel from a fuel source (not shown) through a fuel pipe 47. The fuel pipe 47 is provided with a flow rate adjusting valve 49 that adjusts the amount of fuel supplied.

The reheating furnace 29 extends in the vertical direction on the downstream side of the evaporation tube group 39 of the main furnace 27 and is configured to serve as a passage for combustion gas generated by the combustion of the main burner 33. A reheating burner 51 is provided at the lower part of the reheating furnace 29. Fuel is supplied to the reheat burner 51 through a fuel pipe 53 from a fuel source (not shown). The fuel pipe 53 is provided with a flow rate adjusting valve 55 that adjusts the amount of fuel supplied.
A reheater 57 is provided above the reheat furnace 29.

The superheater 37 includes a U-shaped primary superheater tube (primary loop of the superheater tube) 59 and a secondary superheater tube (secondary loop of the superheater tube) 61.
The primary superheater tube 59 is disposed on the furnace 31 side, and the secondary superheater tube 61 is disposed on the evaporation tube group 39 side with a space therebetween. Adjacent superheater tubes of the primary superheater tube 59 and the secondary superheater tube 61 are connected to communicate with each other.

The end of the primary superheater tube 59 on the furnace 31 side is configured to receive saturated steam from the steam drum 43. A superheater outlet pipe 63 is connected to the end of the secondary superheater pipe 61 on the evaporation pipe group 39 side. The other end of the superheater outlet pipe 63 is connected to the introduction part of the high-pressure turbine 9.
The superheater outlet pipe 63 is provided with a superheat branch pipe 65 that branches in the middle and supplies superheated steam to the reverse turbine 15. The superheater outlet pipe 63 and the superheat branch pipe 65 on the downstream side of the branch part are provided with on-off valves 67 and 69, respectively. By selectively opening and closing the on-off valves 67 and 69, the superheated steam is supplied to either the high-pressure turbine 9 or the reverse turbine 15.

The outlet steam of the high-pressure turbine 9 is introduced into the lower end of the reheater 57 and is heated by the residual heat amount of the combustion gas generated by the combustion of the main burner 33 and the combustion gas of the reheat burner 51. The reheat steam reheated by the reheater 57 is introduced into the intermediate pressure turbine 11 from the upper end of the reheater 57.
The outlet steam of the intermediate pressure turbine 11 is supplied to the low pressure turbine 13, and after the low pressure turbine 13 is rotationally driven, it is sent to a condenser 71 that supplies water to the main furnace 27. The superheated steam supplied to the reverse turbine 15 is sent to the condenser 71 after the reverse turbine 15 is rotationally driven.

Hereinafter, operation | movement of the marine propulsion plant 1 provided with the marine boiler 5 concerning this embodiment comprised in this way is demonstrated.
The combustion gas generated by the combustion of the main burner 33 flows from the furnace 31 to the front bank tube 35 and heats the water flowing in the front bank tube 35. Thereby, a part of calorie | heat amount of combustion gas is absorbed.
At this time, by adjusting the thickness, the arrangement pitch, the amount of water, and the like of the heat transfer tubes constituting the front bank tube 35, the heat amount and the radiant heat amount that can be absorbed by the front bank tube 35, and therefore the primary superheater tube 59 acts. The amount of heat and radiant heat of the combustion gas can be adjusted. When reducing the amount of heat and radiant heat of the combustion gas acting on the primary superheater tube 59, the diameter of the heat transfer tube constituting the front bank tube 35 is increased, the pitch is decreased, or many in the combustion gas flow direction. Arrange rows and so on.
If it does in this way, calorie | heat amount and radiant heat amount of the combustion gas which act on the primary superheater pipe | tube 59 can further be suppressed, and it can suppress that the surface temperature of a primary superheater pipe | tube becomes high temperature and a thinning trouble generate | occur | produces. it can.

The combustion gas then flows through the superheater 37 and exchanges heat with the primary superheater tube 59 and then exchanges heat with the secondary superheater tube 61. Since the superheater 37 is close to the furnace 31, it is heated by the convection heat and radiant heat of the combustion gas, so that it can be heated to a high temperature.
On the other hand, the front bank tube 35 absorbs a part of the heat amount of the combustion gas from the furnace 31 and blocks a part of the radiant heat from the furnace 31, so that the primary superheater pipe 59 and the secondary of the superheater 37 are blocked. Excessive heating to the superheater pipe 61, especially the primary superheater pipe 59, can be suppressed, and the surface temperature of the primary superheater pipe 59 and the secondary superheater pipe 61 becomes high and the occurrence of a thinning trouble is suppressed. can do.

Saturated steam from the steam drum 43 is supplied to the primary superheater pipe 59 and flows through the secondary superheater pipe 61 next to the primary superheater pipe 59, while being superheated by the combustion gas to be superheated steam, Into the outlet pipe 63.
Thus, since the steam is superheated through the primary superheater tube 59 and the secondary superheater tube 61, the heat transfer area of the superheater tube can be made larger than that of the conventional one loop.
For this reason, the temperature of superheated steam can be increased and the efficiency of the marine boiler 5 can be improved.

  At this time, since saturated steam having a low temperature is supplied to the furnace 31 side of the primary superheater tube 59, the saturated steam having a low temperature cools the primary superheater tube 59. Therefore, in particular, it is possible to suppress excessive heating of the primary superheater tube 59 that is exposed to high-temperature combustion gas, and to prevent the surface temperature of the primary superheater tube 59 from becoming high and causing a thinning trouble. .

  The combustion gas from the main burner 33 exchanges heat through the evaporator tube group 39, is mixed with the combustion gas generated by the combustion of the reheat burner 51, is heat exchanged by the reheater 57, and then exhausted.

The superheated steam generated in the superheater 37 is supplied to the high-pressure turbine 9 through the superheater outlet pipe 63 to drive the high-pressure turbine 9 to rotate.
The steam exhausted from the high-pressure turbine 9 is supplied to the reheater 57 and reheated by the combustion gas such as the reheat burner 51. The reheat steam reheated by the reheater 57 is supplied to the intermediate pressure turbine 11 to drive the intermediate pressure turbine 11 to rotate.

The steam exhausted from the intermediate pressure turbine 11 is supplied to the low pressure turbine 13 to rotate the low pressure turbine 13. The steam exhausted from the low pressure turbine 13 is sent to the condenser 79. The water condensed by the condenser 79 is supplied to the main furnace 27.
The rotation of the high-pressure turbine 9 and the intermediate-pressure turbine 11 is transmitted to the speed reducer 23 through the rotation shaft 17, and the rotation of the low-pressure turbine 13 is transmitted through the rotation shaft 21. The speed reducer 23 rotates the propeller shaft 25 at the decelerated rotational speed and rotates the propeller 7.

[Second Embodiment]
Next, a marine boiler according to a second embodiment of the present invention will be described with reference to FIGS.
In this embodiment, since the supply position of the saturated steam to the superheater 37 is different from that in the first embodiment, this different part will be mainly described here, and the same part as that in the first embodiment described above will be duplicated. The description that has been made will be omitted.
In addition, the same code | symbol is attached | subjected to the same member as 1st embodiment.
FIG. 2 is a schematic diagram illustrating a schematic configuration of the marine boiler 5 according to the present embodiment.

In the present embodiment, the saturated steam of the steam drum 43 is supplied to the end of the secondary superheater tube 61 on the side of the evaporator tube group 39. The superheater outlet pipe 63 is connected to the furnace 31 side end of the primary superheater pipe 59.
Saturated steam from the steam drum 43 is supplied to the end of the secondary superheater pipe 61 on the furnace 31 side, and then flows into the primary superheater pipe 59 next to the secondary superheater pipe 61, while being superheated by the combustion gas, It becomes superheated steam and flows into the superheater outlet pipe 63.

In this way, the steam flow and the combustion gas flow in the superheater 37 have a countercurrent relationship. FIG. 3 shows a steam temperature change 73 and a combustion gas temperature change 75 in this embodiment. In addition, FIG. 3 shows, as a comparative example, a steam temperature change 77 when a parallel flow relationship is used as in the first embodiment.
The temperature change 73 can take a large temperature difference between the combustion gas and the steam in the entire flow direction, and can improve the heat exchange efficiency.

  Thereby, for example, even if the heat transfer area of the primary superheater tube 59 is reduced, a predetermined high-temperature superheated steam can be obtained. Since the contact with the combustion gas is reduced, excessive heating of the primary superheater tube 59 can be suppressed, and the occurrence of a thinning trouble due to the high surface temperature of the primary superheater tube 59 can be suppressed. . Therefore, the boiler can be made more compact even under the same steam condition.

The present invention is not limited to the embodiments described above, and various modifications may be made without departing from the spirit of the present invention.
For example, in the said embodiment, although demonstrated as the marine boiler 5 provided with the reheater 57, it is not limited to this. That is, the present invention can also be applied to the marine boiler 5 that does not have the reheater 57.

5 Marine Boiler 31 Furnace 33 Main Burner 35 Front Bank Tube 37 Superheater 39 Evaporation Tube Group 59 Primary Superheater Tube 61 Secondary Superheater Tube

Claims (5)

Combustion gas generated by combustion of a burner is a marine boiler configured to flow from a furnace through a superheater and an evaporation tube group,
The superheater includes a primary loop of a superheater pipe disposed on the furnace side and a secondary loop of a superheater pipe disposed on the evaporator tube group side, and the primary loop and the secondary loop A marine boiler characterized in that the loops are connected in series.   The marine boiler according to claim 1, wherein a front bank tube through which water passes is disposed on the furnace side of the superheater.   The marine boiler according to claim 2, wherein the front bank tubes are arranged in multiple rows.   The marine boiler according to any one of claims 1 to 3, wherein steam flows from the primary loop to the secondary loop in the superheater. The marine boiler according to any one of claims 1 to 3, wherein steam flows from the secondary loop to the primary loop in the superheater.

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