KR20100058644A - Reheat boiler and gas temperature control method of reheat boiler - Google Patents

Abstract

A reheat boiler includes a main boiler arranged such that combustion gas generated through combustion of a burner flows from a furnace through a superheater and an evaporation pipe group; a reheat furnace (108) provided with a reheat burner (107) on the slipstream side of the evaporation pipe group; and a reheater (109) on the upper side of the reheat furnace (108) wherein a combustion air supply portion (12) for supplying a portion of combustion air as combustion air (11b) is provided at a position opposing the reheat burner (107) in the reheat furnace (108). Mixing of combustion gas (107a) and the combustion air (11b) is accelerated by counter collision thereof to cause a flow pattern of the combustion gas to be varied and so unbalance in temperature of the combustion gas (107a) to be reduced at the outlet of the reheat furnace (108).

Description

Reheat Boiler and Gas Temperature Control Method of Reheat Boiler {REHEAT BOILER AND GAS TEMPERATURE CONTROL METHOD OF REHEAT BOILER}

The present invention relates to a reheat boiler and a method of controlling the gas temperature of a reheat boiler which provide a reheater on the downstream side of the evaporation tube group and reduce unbalance of the gas temperature of the combustion gas near the outlet of the reheater.

Conventionally, what has a superheater is employ | adopted as a boiler for ships (patent document 1). Moreover, the reheat boiler provided with the reheat furnace and the reheater on the downstream side of the combustion gas of the conventional marine boiler is used.

An example of the structure of the conventional marine reheat boiler is shown in FIG. 6 is a schematic diagram schematically showing the configuration of a conventional reheat boiler. As shown in FIG. 6, the conventional reheat boiler 100 includes a burner 101, a furnace 102, a front bank tube 103, a superheater (SH) 104, and an evaporation tube group (rear bank tube). ) Main boiler 106 consisting of a (105), a reheating furnace 108 having a reheat burner 107 on the downstream side of the evaporation tube group 105, and a reheater 109 provided on the exhaust gas outlet side. Is done. Combustion gas generated by combustion of the burner 101 flows from the furnace 102 to the front bank tube 103, the superheater 104, and the evaporation tube group 105, and the combustion gas and the reheat furnace of the reheat burner 107 ( 108, and flows while performing heat exchange with the reheater 109, and flows out from the gas outlet 110 to operate efficiently.

In Fig. 6, reference numeral 111 denotes a water drum, 112 a steam drum, 113 and 114 a header, and 115 a wall tube.

Patent Document 1: Japanese Patent Application Laid-Open No. 2002-243106

By the way, in the conventional reheat boiler 100 for ships, the reheat burner 107 is provided only in the front wall side of the reheating furnace 108, and is not provided in the rear wall side of the reheating furnace 108. For this reason, as shown in FIG. 7, the front wall (in FIG. 7, X) side and the rear wall (FIG. 7) of the reheating path 108 are shown by the exit side (part B of FIG. 6) of the reheating furnace 108. FIG. Among them, there is a problem that large unbalance occurs in the combustion gas temperature on the Y) side.

Unbalance of the combustion gas temperature at the outlet side of the reheating furnace 108 (that is, the inlet side of the reheater 109) decreases the heat transfer performance of the reheating furnace 108 and the reheater 109 and at the same time the reheater There exists a problem that it may cause high temperature corrosion of the reheating tube of 109 and the strength fall of a support material. In addition, in FIG. 7, the code | symbol A is a part of a reheat burner, and the code | symbol C represents the exit part of the reheater 109. As shown in FIG.

In view of the above problems, the present invention provides a reheat boiler and a gas temperature control method for a reheat boiler, by which the unbalance of the gas temperature of the combustion gas at the outlet side of the reheat furnace is reduced by changing the flow pattern of the gas of the reheat burner. It is a task.

The 1st invention of this invention for solving the above-mentioned subject is a main boiler comprised by the combustion gas which arose by combustion of a burner through a superheater, an evaporation tube group from a furnace, and a reheat burner on the downstream side of the said evaporation tube group. And a reheat boiler having a reheater on the upper side of the reheater, and having a combustion air supply unit for supplying a part of combustion air to a position facing the reheat burner in the reheater. It is in a reheat boiler characterized by.

2nd invention is a reheating boiler characterized in that in the 1st invention, the said combustion air supply part is provided in at least 2 or more steps in the height direction in the said reheating furnace.

3rd invention is a reheating boiler characterized by inject | pouring a part of said combustion air in the ratio of 50% or less in the said combustion air supply part in 1st invention.

According to a fourth aspect of the present invention, in the combustion air supply unit, at least two stages or more are provided in the height direction in the reheating furnace, and the combustion air supply unit supplies a part of the combustion air in a different amount for each combustion air supply unit. The reheat boiler is characterized in that.

5th invention is a gas temperature control method of the reheating boiler of any one of 1st-4th invention, and supplies a part of combustion air into the said reheating furnace from the position which opposes the said reheating burner, The gas temperature control method of a reheat boiler characterized by reducing the unbalance of the gas temperature of the combustion gas at an exit side.

According to the present invention, since a part of the combustion air is supplied into the reheat furnace from the combustion air supply unit which is installed at the position opposite to the reheat burner in the reheat furnace, the flow pattern of the gas ejected from the reheat burner can be changed. Therefore, the unbalance of the gas temperature of the combustion gas at the outlet side of the reheating furnace can be reduced.

Fig. 1A is a schematic diagram briefly showing the configuration of a reheating furnace and a reheater of a reheat boiler according to the first embodiment of the present invention.
It is sectional drawing seen from the direction orthogonal to the perpendicular direction of the reheating furnace in FIG. 1A.
FIG. 2 is a schematic diagram schematically showing a configuration of a reheat boiler according to the first embodiment of the present invention. FIG.
3 is an explanatory diagram showing a temperature distribution of combustion gas near an exit of a reheating furnace.
4 is a diagram schematically showing the configuration of only the reheat furnace and the reheater portion of the reheat boiler according to the second embodiment of the present invention.
It is explanatory drawing which shows the temperature distribution of the combustion gas in the vicinity of the exit of a reheating furnace.
6 is a schematic diagram schematically showing an example of the configuration of a conventional reheat boiler.
7 is an explanatory diagram showing a temperature distribution in the vicinity of an exit of a conventional reheating furnace.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail, referring drawings. In addition, this invention is not limited by this Example. In addition, the component in the following Example includes what can be easily estimated by a person skilled in the art, or what is substantially the same.

<First Embodiment>

A reheat boiler according to an embodiment of the present invention will be described with reference to the drawings.

Since the reheat boiler according to the present embodiment is provided with an air supply unit in the reheat furnace similarly to the structure of the conventional reheat boiler shown in FIG. 6, the same number is given to the same member, and redundant description is omitted.

FIG. 1A is a schematic diagram schematically showing the configuration of a reheater and a reheater of the reheat boiler according to the first embodiment of the present invention, and is a sectional view taken along the line I-I of FIG. 2. FIG. 1B is a sectional view seen from a direction orthogonal to the vertical direction of the reheating furnace in FIG. 1A, and FIG. 2 is a schematic diagram schematically showing the configuration of the reheating boiler according to the first embodiment of the present invention.

In addition, in FIG. 1A and 1B, the code | symbol X is a front wall side by reheat, and the code | symbol Y is a rear wall side of a reheat furnace.

As shown in FIG. 1A, FIG. 1B, and FIG. 2, the reheat boiler 10A which concerns on a present Example is burned by the burner 101 similarly to the structure of the conventional reheat boiler shown in FIG. The generated combustion gas is passed through the superheater 104 and the evaporation tube group 105 from the furnace 102, and the reheat furnace 108 in which the combustion gas is reburned by the reheat burner 107; The reburned combustion gas is a reheat boiler configured to pass through the reheater 109 and at the position opposite to the reheat burner 107 in the reheat furnace 108, as shown in FIGS. 1A and 1B. It has a combustion air supply part 12 which supplies a part of combustion air 11a supplied to the reheat burner 107 as combustion air 11b.

In the present invention, the combustion air supplied to the reheat burner 107 in the combustion air 11 is referred to as combustion air 11a and the reheat burner 107 in the combustion air 11. The remaining air supplied and supplied to the combustion air supply unit 12 is referred to as combustion air 11b.

By installing the combustion air supply part 12 in the reheat furnace 108 opposite the reheat burner 107, the combustion gas 107a and the combustion air supply part 12 ejected from the reheat burner 107 are provided. Since the supplied combustion air 11b collides against each other and the mixing of the combustion gas 107a with the combustion air 11b is promoted, the unbalance of the temperature of the combustion gas 107a at the outlet of the reheating furnace 108 is prevented. Can be reduced.

3 is explanatory drawing which shows the temperature distribution of the combustion gas in the exit of the reheating furnace shown in FIG. 1A. As shown in FIG. 3, the combustion air supply part 12 is installed in the reheating furnace 108 at the position facing the reheat burner 107, and the combustion air 11b is supplied into the reheating furnace 108. As shown in FIG. The width of the temperature distribution of the combustion gas 107a in the vicinity of the exit of the reheating furnace 108 (symbol B in FIGS. 1A and 2) is, for example, 600 to 800 ° C., and is shown in FIG. 7. It becomes narrower than the temperature distribution of the combustion gas 107a of the exit vicinity of the reheating furnace 108 in FIG. 6 and FIG. 7 in the reheat boiler 100, and can maintain about 700 degreeC on average.

Therefore, by supplying the combustion air 11 to the reheating furnace 108 from the position facing the reheating burner 107, near the outlet of the reheating furnace 108 in the conventional reheating boiler as shown in FIG. In FIG. 6, FIG. 7, the unbalance of the temperature near the outlet of the reheating furnace 108 can be suppressed compared to the temperature of the combustion gas 107a indicated by the reference B. FIG.

In addition, in the reheat boiler 10A according to the present embodiment, the combustion air 11b includes the combustion air 11b except for the combustion air 11a supplied to the reheat burner 107 among the combustion air 11. It is preferable to supply at a ratio of 50% or less from (12). This is because the fuel is not sufficiently burned in the reheat burner 107 when the combustion air 11 is used as the combustion air 11b a lot.

In the reheat boiler 10A according to the present embodiment, the combustion gas 107a is supplied from the combustion air supply unit 12 after burning with the combustion air 11a supplied to the reheat burner 107. It combusts with the air 11b for combustion, and is made to input in steps. By this reason, the combustion gas (107a) 2-stage combustion by air (11a, 11b) for the combustion can be suppressed the generation of NO _X.

In addition, in 10 A of reheat boilers concerning this embodiment, the air amount of the combustion air 11b supplied from the combustion air supply part 12 is adjusted by air amount adjustment means, such as a damper, for example.

Therefore, according to the reheat boiler 10A according to the present embodiment, the combustion air 11b is reheated from the combustion air supply unit 12 installed at the position facing the reheat burner 107 in the reheating furnace 108. By supplying into the furnace 108, the flow pattern of the combustion gas 107a ejected from the reheat burner 107 can be changed, thereby reducing the unbalance of the gas temperature of the combustion gas 107a at the outlet side of the reheat furnace 108. can do. Thereby, the fall of the heat transfer performance of the reheating furnace 108 and the reheater 109 can be prevented, and the high temperature corrosion of the reheating tube of the reheater 109 and the fall of the strength of a support material can be prevented.

Second Embodiment

The reheat boiler according to the second embodiment according to the present invention will be described with reference to FIGS. 4 and 5.

4 is a diagram schematically showing the configuration of only the reheat furnace and the reheater portion of the reheat boiler according to the second embodiment of the present invention.

Since the reheat boiler according to the present embodiment is the same as that of the reheat boiler according to the first embodiment, the same number is given to the same member, and duplicated description is omitted.

As shown in FIG. 4, the reheat boiler 10B which concerns on a present Example has the three stage which shifted the position in the height direction of the reheating furnace 108 to the opposite position of the reheat burner 107 of the reheating furnace 108. As shown in FIG. The combustion air supply parts 12-1 to 12-3 are provided.

By supplying the combustion air 11b-1 to 11b-3 to the reheating furnace 108 from the air supply parts 12-1 to 12-3, the combustion gas with the combustion air 11b-1 to 11b-3 The degree of mixing can be arbitrarily adjusted to control the temperature distribution of the combustion gas near the outlet of the reheating furnace 108.

Moreover, in the boiler 10B which concerns on an Example, the flow volume of the combustion air 11b-1-11b-3 supplied to each by the air supply parts 12-1-1212 is adjusted. By adjusting the flow rates of the combustion air 11b-1 to 11b-3 supplied to the reheating furnace 108, the degree of mixing of the combustion gas 107a with the combustion air 11b-1 to 11b-3 is adjusted. The temperature distribution near the outlet of the reheating furnace 108 can be controlled. For example, the temperature distribution in the vicinity of the outlet of the reheating furnace 108 is made by making the air amount of the combustion air 11b-1 relatively large, and equalizing the air amount of the combustion air 11b-2, 11b-3. Can be equalized.

5 is explanatory drawing which shows the temperature distribution of the combustion gas in the vicinity of the exit of the reheating furnace shown in FIG. As shown in FIG. 4, as shown in FIG. 5, by adjusting the flow volume of the combustion air 11b-1-11b-3 supplied by the combustion air supply parts 12-1-12-3, Unbalance of the gas temperature of the combustion gas 107a at the exit side of the reheating furnace 108 can be reduced.

In this way, the combustion air 11b is divided into multiple stages and supplied into the reheating furnace 108, so that the width of the temperature distribution of the combustion gas 107a near the outlet of the reheating furnace 108 (symbol B in FIG. 4) is increased. For example, it becomes 620-780 degreeC, and the temperature of the combustion gas 107a of the exit vicinity of the reheating furnace 108 (symbol B in FIG. 6) in the conventional reheat boiler 100 as shown in FIG. It becomes narrower than distribution and can maintain about 700 degreeC on average.

In addition, in the reheat boiler 10A according to the first embodiment as shown in FIG. 3, the temperature is more uniform than the temperature distribution of the combustion gas 107a near the outlet of the reheating furnace 108 (symbol B in FIG. 2). It can be done.

Therefore, the combustion air 11b-1 to 11b-3 is supplied to the reheating furnace 108 from the position which opposes the reheat burner 107, and the air volume of the combustion air 11b-2 and 11b-3 is minutely adjusted. By adjusting, the unbalance of the temperature near the exit of the reheating furnace 108 can be suppressed.

Further, by finely adjusting the flow rate of the air 11b-1 to 11b-3 for combustion, the reduction zone conditions such as temperature and residence time can be adjusted, so that generation of NO _X can be suppressed. For example, generation of NO _X is made by reducing the flow rate of the combustion air 11b-1, increasing the flow rate of the combustion air 11b-3, and making the inside of the reheating furnace 108 insufficient air. Can be suppressed.

Therefore, according to the reheat boiler 10B according to the present embodiment, a plurality of combustion air supply units 12-1 provided by shifting the position in the height direction at a position opposed to the reheat burner 107 of the reheating furnace 108. 12-3 to supply the combustion air 11b-1 to 11b-3 and finely adjust the flow rate of the combustion air 11b-1 to 11b-3 supplied to the reheating furnace 108 to thereby reheat. Since the gas flow pattern of the burner 107 can be changed, the unbalance of the gas temperature of the combustion gas 107a at the exit side of the reheating furnace 108 can be further reduced. Thereby, the fall of the heat transfer performance of the reheating furnace 108 and the reheater 109 can be prevented, and the high temperature corrosion of the reheating tube of the reheater 109 and the fall of the strength of a support material can be prevented.

In addition, the degree of mixing of the combustion gas 107a with the combustion air 11b-1 to 11b-3 can be finely adjusted to control the temperature distribution at the outlet portion of the reheating furnace 108. In addition, since the air amount of the combustion air 11b-1 to 11b-3 can be fine-adjusted and the conditions for the reduction region of the reheating furnace 108 can be adjusted, generation of NO _X can be suppressed.

In the reheat boiler 10B according to the present embodiment, although the positions are shifted in the height direction in the reheating furnace 108, three stages of the air supply units 12-1 to 12-3 for combustion are provided. The invention is not limited to this, and the air supply unit 12 may be provided in three or more stages.

In addition, the reheat boilers 10A and 10B according to the present invention supply part of the combustion air 11b into the reheat furnace 108 from a position facing the reheat burner 107 in the reheat furnace 108. Since the flow pattern of combustion gas can be changed and the unbalance of the gas temperature of the combustion gas at the exit side of the reheating furnace 108 can be reduced, it can be used as a marine boiler, but this invention is not limited to this.

As described above, in the reheat boiler and the gas temperature control method of the reheat boiler according to the present invention, at least one air supply unit for combustion is provided at a position opposite to the reheat burner in the reheat furnace and shifted in the height direction in the reheat furnace. Since the flow pattern of combustion gas can be changed by supplying a part of combustion air from the inside into a reheat furnace, it is suitable for use in a reheat boiler for ships aiming at the reduction of the unbalance of the gas temperature of the combustion gas at the exit side of a reheat furnace. .

10A, 10B: Reheat Boiler
11, 11b-1 to 11b-3: combustion air
12, 12-1 to 12-3: air supply for combustion
101: burner
102: brazier
103: front bank tube
104: superheater (SH)
105: evaporation tube group (rear bank tube)
106: main boiler
107: reheat burner
108: reheat
109: reheater
110: gas outlet
111: water drum
112: steam drum
113, 114: header
115: wall tube

Claims (5)

The combustion gas generated by the combustion of the burner flows from the furnace through the superheater and the evaporator tube group, the reheat furnace having a reheat burner on the downstream side of the evaporator tube group, and the ash on the upper side of the reheat furnace. Is a reheat boiler with hot air,
And a combustion air supply unit for supplying a part of combustion air at a position opposed to the reheat burner in the reheat furnace. The reheat boiler according to claim 1, wherein the combustion air supply unit is provided in at least two stages in a height direction in the reheating furnace. The reheat boiler according to claim 1, wherein a part of the combustion air is introduced into the combustion air supply unit at a rate of 50% or less. The said combustion air supply part is provided in at least 2 or more stages in the height direction in the said reheating furnace, and supplies a part of said combustion air of a different quantity for every combustion air supply part, The said air supply part of Claim 1 characterized by the above-mentioned. , Reheat boiler. The gas temperature control method of the reheat boiler of any one of Claims 1-4,
A part of combustion air is supplied into the said reheating furnace from the position facing the said reheat burner, and the unbalance of the gas temperature of the combustion gas at the exit side of the said reheating furnace is reduced, The gas temperature control method of the reheating boiler.

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