KR20210114501A - Boiler - Google Patents

Abstract

Provided is a boiler capable of cooling the sub-burner even when the small-capacity sub-burner is inactive while the large-capacity main burner is operating. A combustion vessel 11 forming the combustion chamber 24, a main burner formed in the combustion vessel 11, a main burner formed in the combustion vessel 11 and formed on the downstream side of a flame formed by the main burner The sub-burner 13 having a smaller capacity and the sub-burner 13 are accommodated, and air is supplied to the sub-burner wind box 40 and the sub-burner wind box 40 mounted in the combustion vessel 11. It is provided with the air fan 44 for sub-burners, and the control part which controls the air fan 44 for sub-burners. The control unit includes an air fan 44 for the sub-burner so that the pressure in the wind chamber 40 for the sub-burner becomes higher than the pressure in the combustion vessel 11 when the main burner is in operation and when the sub-burner 13 is not in operation. to control

Description

Boiler

The present invention relates to a boiler.

Boilers are known which form a flame in a combustion chamber by means of a burner to produce steam. The following patent document 1 discloses a boiler for ships mounted on a ship. The boiler disclosed in the same document is capable of handling from large capacity to small capacity by providing a burner of a small capacity in addition to a burner of a large capacity.

Japanese Public Utility Model Publication No. 57-81999

As a boiler mounted on a ship, there is a periodic boiler used as a power source for driving a propeller for propulsion. As a boiler having a smaller capacity than the main boiler, there is an auxiliary boiler used as an auxiliary power source for operating various devices mounted on a ship or driving an arrester.

The auxiliary boiler for generating high-pressure steam for high-load equipment and for generating low-pressure steam for low-load equipment may be required respectively. As a result, it causes an increase in the equipment score of the ship. In addition, since the auxiliary boiler requires time to increase the pressure, it is also necessary to continue the warm-up operation in order to quickly supply steam to the equipment. For this reason, especially the increase in fuel consumption by warm-up operation of the auxiliary boiler which produces|generates high pressure steam becomes a problem.

Then, by providing burners from which capacity|capacitance differs like patent document 1, it is made to correspond from a large capacity to a small capacity, and aiming at high turn-down is considered.

However, during operation of the large-capacity burner, the small-capacity burner is stopped, and there is a fear that the small-capacity sub-burner is damaged by the radiant heat of the flame of the large-capacity main burner.

The present disclosure has been made in view of such circumstances, and an object of the present disclosure is to provide a boiler capable of cooling a small-capacity burner when the large-capacity main burner is operating.

A boiler according to an aspect of the present disclosure includes a combustion vessel forming a combustion chamber, a main burner installed in the combustion vessel, and a flame installed in the combustion vessel and formed on the downstream side of the flame formed by the main burner, and the an air supply means for supplying air to a sub-burner having a smaller capacity than the main burner, a sub-burner wind box mounted to the combustion vessel while accommodating the sub-burner, and air to the sub-burner wind box; and a control unit for controlling, wherein the control unit drives the air supply means when the main burner is in operation and when the sub burner is not in operation.

A secondary burner is installed on the downstream side of the flame formed by the main burner. For this reason, when the main burner is in operation and when the secondary burner is not in operation, if combustion air is not supplied to the secondary burner, there is a fear that the secondary burner may be damaged by radiant heat from the flame by the main burner. Therefore, even when the sub-burner is not in operation, air is supplied from the air fan for the sub-burner to cool the sub-burner. Moreover, since air was supplied so that the pressure in the wind chamber for sub-burners may become higher than the pressure in a combustion container, with respect to the combustion chamber in a pressurized state, the sub-burner and the wind chamber for sub-burners can be sealed.

The control unit may control the air supply means so that the pressure in the wind chamber for the secondary burner becomes higher than the pressure in the combustion vessel when the main burner is in operation and when the secondary burner is not in operation.

In the boiler according to an aspect of the present disclosure, a cooling steam supply unit for supplying cooling steam for cooling the sub-burner is provided.

Further, since cooling steam is supplied, damage to the sub-burner due to radiant heat can be suppressed.

In the boiler according to an aspect of the present disclosure, the sub-burner includes an oil injection nozzle that injects oil fuel as a combustion fuel into the combustion chamber, and the oil injection nozzle is a part of the cooling steam supply unit.

Since oil is not supplied to the oil jet nozzle of the sub-burner during non-operation, the oil jet nozzle is a part of the cooling steam supply unit, and the cooling steam is supplied from the oil jet nozzle. Since the oil injection nozzle injects cooling steam from the tip of the sub-burner toward the inside of the combustion chamber, it is possible to effectively protect the sub-burner from radiant heat.

In the boiler according to an aspect of the present disclosure, a steam supply nozzle is formed as a part of the cooling steam supply unit in the wind chamber for the secondary burner.

In the wind chamber for secondary burners, a vapor supply nozzle was provided as a part of a cooling vapor supply part. Thereby, it is possible to cool the sub-burner accommodated in the wind box for the sub-burner. In addition, since a path for supplying the cooling steam can be formed separately from the fuel nozzle of the sub-burner, the cooling steam can be supplied regardless of the operation of the sub-burner.

As a vapor supply nozzle, it can be set as the vapor|steam ring nozzle which consists of a ring-shaped nozzle which surrounds a secondary burner, for example.

In the boiler according to an aspect of the present disclosure, the sub-burner includes a gas injection nozzle that injects gaseous fuel as a combustion fuel into the combustion chamber, and the gas injection nozzle is a part of the cooling steam supply unit.

The sub-burner is equipped with a gas injection nozzle so that gas fuel can be used in addition to oil fuel. The gas injection nozzle was made a part of the cooling vapor supply part, and the cooling vapor was supplied from the gas injection nozzle. Since the gas injection nozzle injects cooling vapor|steam toward the inside of a combustion chamber from the front-end|tip of a sub-burner, it can protect a sub-burner from radiant heat effectively.

In the boiler according to an aspect of the present disclosure, the cooling steam supply unit supplies cooling steam toward the downstream side of the flame formed by the main burner.

By supplying steam to the downstream side of the flame of the main burner, the flame temperature can be lowered and thermal NOx can be reduced.

In the boiler related to an aspect of the present disclosure, an air fan for a main burner for supplying air to a wind box for a main burner mounted to the combustion vessel while accommodating the main burner, and air to a wind box for the main burner, and the main burner and an air supply pipe for supplying air from the air fan to the wind chamber for the sub-burner.

It was assumed that air was supplied from the air fan for the main burner to the wind chamber for the sub-burner. Accordingly, even if the air fan for the sub-burner fails, cooling air can be supplied to the wind chamber for the sub-burner.

Moreover, the air supply from the air fan for main burners to the wind box for sub-burners is controlled by a control part. That is, when the air fan for a sub-burner does not fail, the control part controls an on-off valve etc. so that the flow of air may be stopped. When the air fan for the sub-burner fails, the control unit controls the on/off valve and the like so that air flows. Moreover, it is not limited to the malfunction of the air fan for sub-burners, You may make it supply air to the wind box for sub-burners from the fan for sub-burners when the amount of air supplied from the air fan for sub-burners is insufficient.

In the boiler according to an aspect of the present disclosure, a damper for opening and closing a flow path is formed at the outlet of the air supply means.

A damper was provided at the outlet of the air supply means. Thereby, by closing the damper when the air supply means is stopped, it is possible to prevent the air induced from the main burner air fan through the air supply pipe from flowing backward to the air supply means side.

Even when the sub-burner is inactive while the main burner is operating, since air is supplied from the air supply means, the sub-burner can be cooled.

BRIEF DESCRIPTION OF THE DRAWINGS It is a longitudinal sectional view which showed the boiler which concerns on 1st Embodiment.
FIG. 2 is a cross-sectional view taken along line AA of FIG. 1 .
3 is a cross-sectional view showing a schematic configuration of a sub-burner.
Fig. 4 is a side view showing a state in which an air fan is connected to the boiler.
Fig. 5 is a schematic configuration diagram showing a fuel oil path and a steam path of a sub-burner applied to the boiler according to the second embodiment.
6 is a cross-sectional view showing a boiler according to a third embodiment.
Fig. 7 is a front view showing the vapor ring nozzle of Fig. 6;

EMBODIMENT OF THE INVENTION Below, embodiment which concerns on this indication is described with reference to drawings.

[First Embodiment]

EMBODIMENT OF THE INVENTION Hereinafter, 1st Embodiment of this indication is described.

The boiler of this embodiment is demonstrated as a boiler for ships mounted on a ship. Specifically, it demonstrates as a case where a boiler is used as an auxiliary boiler which produces|generates the steam for various purposes for driving the steam turbine for cargo oil pumps, etc., for example. However, a boiler is not limited to an auxiliary boiler, For example, in the case of a ship, it can use also as a main boiler which becomes a power source at the time of navigation, or an auxiliary boiler which operates the machine mounted on the ship. The boiler is not limited to the use for ships, It can be used for the boiler of various uses.

<Entire configuration of boiler>

As shown in FIG. 1 , the boiler 10 includes a combustion vessel 11 , a main burner 12 , a sub-burner 13 , an evaporator 14 , and a control unit 15 .

The combustion vessel 11 has a box shape, and a combustion chamber 24 is formed therein. The combustion chamber 24 is in a pressurized state during operation of the main burner 12 or the sub-burner 13 . In addition, the operation of the burners 12 and 13 means a state in which a flame is formed, and the non-operation means a state in which a flame is not formed.

The combustion vessel 11 includes a ceiling portion 11a, a bottom portion 11b, a front wall portion 11c (see Fig. 2), a rear wall portion 11d (see Fig. 2), and a pair of side wall portions 11e. , 11f). A gas outlet 22 is formed in the ceiling 11a. The bottom portion 11b is formed to face the ceiling portion 11a. The front wall portion 11c, the rear wall portion 11d, and the pair of side wall portions 11e and 11f extend so as to connect between the ceiling portion 11a and the bottom portion 11b. The ceiling portion 11a, the bottom portion 11b, the front wall portion 11c, the rear wall portion 11d, and the side wall portion 11e form the combustion chamber 24 . The combustion chamber 24 is partitioned by the ceiling part 11a, the bottom part 11b, the front wall part 11c, the rear wall part 11d, the side wall part 11e, and the front bank tube 28 mentioned later, and it is comprised. Towards the combustion chamber 24, the main burner 12 and the sub-burner 13 face.

The combustion vessel 11 has an exhaust chamber 33 partitioned by a ceiling portion 11a, a bottom portion 11b, a front wall portion 11c, a rear wall portion 11d, a side wall portion 11f, and an evaporation tube 25 to be described later. ) is installed. A gas outlet 22 communicates with the exhaust chamber 33 . In the combustion vessel 11 , a partition 29 is formed in the vicinity of the central portion of the evaporator 14 and the front bank tube 28 in the height direction (up-down direction in FIG. 1 ). The partition 29 forms the gas outlet side passage 23 between the bottom part 11b in the area|region where the evaporator 14 and the front bank tube 28 are arrange|positioned. The gas outlet side passage 23 is a passage for the combustion gas G that mainly flows from the combustion chamber 24 to the exhaust chamber 33 .

One main burner 12 is provided in the position spaced apart from the gas outlet 22 on the side wall part 11e side of the ceiling part 11a. In addition, although the main burner 12 is one in this embodiment, plural number may be sufficient as it. The main burner 12 is connected to a fuel supply line and an air supply line. The main burner 12 has an igniter, not shown. The main burner 12 burns fuel gas in the combustion chamber 24 surrounded by the ceiling part 11a, the bottom part 11b, and the side wall part 11e, and forms the flame F1 which faces the bottom part 11b side. .

One sub-burner 13 is provided in the front wall part 11c, as shown in FIG. In addition, although the sub-burner 13 is one in this embodiment, plural number may be sufficient as it. The sub-burner 13 is connected to a fuel supply line and an air supply line different from the main burner 12 . The sub-burner 13 has an igniter, not shown, different from the main burner 12 . The sub-burner 13 burns fuel oil and/or fuel gas in the combustion chamber 24, and as shown in FIG. 2, the flame F2 which goes from the front wall part 11c to the rear wall part 11d is formed. do. The sub burner 13 has a smaller capacity than the main burner 12 . In the present embodiment, the capacity of the sub burner 13 is, for example, 1/5 or more and 1/3 or less of the capacity of the main burner 12 .

The sub-burner 13 is accommodated in the wind box 40 for sub-burners, as shown in FIG. The wind box 40 for secondary burners is formed so that it may protrude outward from the front wall part 11c. In the wind box 40 for sub-burners, air AR1 for sub-burners is supplied. The sub-burner air AR1 is used as the combustion air of the sub-burner 13, and is also used as sealing air or cooling air so as to be described later.

The sub-burner 13 is equipped with the oil injection nozzle 13a which injects oil fuel, and the gas injection nozzle 13b which injects gaseous fuel, as shown in FIG. The oil injection nozzle 13a is located at the center in the cross section of the sub burner 13 . A plurality of gas injection nozzles 13b are formed centering on the oil injection nozzle 13a at predetermined angular intervals. The periphery of the oil injection nozzle 13a and the gas injection nozzle 13b becomes a flow path through which the air AR1 for sub-burners (refer FIG. 2) flows. In addition, the number of objects of the oil injection nozzle 13a and the gas injection nozzle 13b is not limited to FIG. 3, The oil injection nozzle 13a may be plural, and more gas injection nozzles 13b may be provided. .

The sub burner 13 is provided in the front wall part 11c from the bottom part 11b side of the combustion vessel 11 rather than the main burner 12, as shown in FIG.1 and FIG.2. As shown in FIG. 1, the sub-burner 13 is provided at a position near the lower end that is downstream of the flame F1 formed by the main burner 12, and air can be supplied to the lower end of the flame F1. has been More specifically, the sub-burner 13 is, as an example, an unillustrated wall tube and a front bank tube 28 formed on the side wall portion 11e in the width direction of the combustion chamber 24 (left-right direction in Fig. 1). ) is installed in the center of the The sub-burner 13 is provided in the central part of the gas outlet side passage 23 in the height direction (up-and-down direction in FIG. 1) of the combustion chamber 24 as an example. In addition, the sub-burner 13 may be provided near the center of the wall tube and front bank tube 28 (not shown) formed on the side wall portion 11e, or may be provided near the center of the gas outlet passage 23 . .

The evaporator 14 is constituted by an evaporating tube group in which a plurality of evaporating tubes 25 are bundled. The plurality of evaporation tubes 25 are arranged in the combustion vessel 11 along the fuel gas ejection direction of the main burner 12 . The plurality of evaporation tubes 25 have a lower end connected to a water drum 26 supported by a bottom portion 11b and an upper end connected to a vapor drum 27 supported by a ceiling portion 11a. The evaporator 14 is disposed as a front bank tube 28 by having a part of the evaporation tube 25 bent toward the front wall portion 11c side.

The boiler 10 has a combustion chamber 24, a front bank tube 28, an evaporator 14, and an exhaust chamber 33 from the main burner 12 and the secondary burner 13 toward the gas outlet 22. are arranged in order. In addition, a plurality of wall tubes (furnace wall tubes) not shown as heat exchangers are formed on each wall surface of the combustion vessel 11 . Between the evaporator 14 and the front bank tube 28, a superheater for superheating the steam in the steam drum 27 to generate superheated steam may be provided.

In the boiler 10, the main burner 12 or the sub-burner 13 injects fuel into the combustion chamber 24 and burns it, so that the flame F1 or the flame F2 is formed, and the combustion gas G is produced|generated . The generated combustion gas G flows from the side wall part 11e side of the combustion vessel 11 to the side wall part 11f side. At this time, the combustion gas G passes sequentially from the combustion chamber 24 through the area where the front bank tube 28 is disposed and the area where the evaporator 14 is disposed to reach the exhaust chamber 33 . The combustion gas G passes through the front bank tube 28 and the evaporator 14 mainly through the lower region in FIG. 1 that is short-circuited by the partition 29, that is, the gas outlet side passage 23. And the combustion gas G mainly changes direction to the upper area|region in FIG. 1 which was short-circuited by the partition 29 in the exhaust chamber 33, passes through the evaporator 14 again, and gas Exit 22 is reached. The front bank tube 28 and the evaporator 14 are heat exchangers, respectively, and when the combustion gas G passes, heat exchange with the combustion gas G is performed, and the heat of the combustion gas G is It recovers and raises the temperature of water or steam (fruit) flowing inside.

The front bank tube 28 is arranged on the side of the main burner 12 and the sub-burner 13 in the combustion vessel 11 , that is, in a region where the temperature inside the combustion vessel 11 is high. The front bank tube 28 is connected to the water drum 26 and the steam drum 27, and water and steam are circulating therein. The front bank tube 28 recovers heat of the combustion gas G by heat exchange between the combustion gas G and water or steam, thereby increasing the temperature of water or steam and lowering the temperature of the combustion gas G make it

The evaporator 14 has a plurality of evaporator tubes 25 , and is disposed on the gas outlet 22 side rather than the front bank tube 28 in the combustion vessel 11 . In the evaporator 14, the combustion gas G that has passed through the region where the front bank tube 28 is disposed passes. In the evaporator 14 , a water drum 26 and a steam drum 27 are connected to each end of the plurality of evaporation pipes 25 , respectively, and water and steam are circulating in each of the evaporation pipes 25 . When the evaporator 14 flows from the water drum 26 to the steam drum 27 through the respective evaporator tubes 25, the combustion gas G is heated by heat exchange between the combustion gas G and water or steam. By recovering heat, the temperature of water or steam is raised and the temperature of the combustion gas G is lowered. That is, when the water and steam in each evaporation tube 25 are heated by the combustion gas G, only steam rises and reaches the steam drum 27. As shown in FIG.

The combustion gas G that has passed through the evaporator 14 is discharged from the gas outlet 22 as exhaust gas (combustion gas G) as heat is recovered and the temperature is lowered to reach the exhaust chamber 33 . do.

The combustion vessel 11 and the wind chamber 40 are respectively provided with pressure sensors (not shown). The output of each pressure sensor is transmitted to the control part 15 .

The control unit 15 controls the operation of the boiler, such as the above-described main burner 12 and sub-burner 13 . The control unit is constituted of, for example, a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and a computer-readable storage medium. A series of processing for realizing various functions is stored in a storage medium or the like in the form of a program as an example, and the CPU reads the program into RAM or the like and executes information processing and arithmetic processing, whereby various functions are implemented. come true Further, the program may be applied in a form in which it is installed in advance in a ROM or other storage medium, in a form in which it is stored in a computer-readable storage medium, in a form in which it is delivered through a communication means by wire or wireless, etc. . The computer-readable storage medium is a magnetic disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.

<Cooling structure of sub-burner 13>

Next, the cooling structure of the sub-burner 13 is demonstrated using FIG.

The air fan 44 for sub-burners is connected to the wind box 40 for sub-burners via the air duct 42 for sub-burners. By the air fan 44 for sub-burners, air AR1 for sub-burners (refer FIG. 2) is supplied into the wind box 40 for sub-burners. The start and stop of the air fan 44 for sub-burners is controlled by the control part 15 (refer FIG. 1). Moreover, you may make it adjust the air flow rate by controlling the rotation speed of the air fan 44 for sub-burners by the control part 15. As shown in FIG.

At the outlet of the sub-burner air fan 44, a damper 46 for opening and closing the flow path is provided. Opening/closing of the damper 46 is controlled by a command from the control unit 15 . One end of the air supply pipe 48 is connected to the downstream side of the damper 46 and to an intermediate position of the air duct 42 for sub-burners. The other end of the air supply pipe 48 is connected to the intermediate position of the air duct 50 for main burners. The air supply pipe 48 is provided with an on-off valve 49 . The on-off valve 49 is controlled by the control unit 15 .

An air fan 52 for main burners is connected to the upstream end of the air duct 50 for main burners. The start and stop of the air fan 52 for main burners is controlled by the control part 15 (refer FIG. 1). Moreover, you may make it control the rotation speed of the air fan 52 for main burners by the control part 15, and make it adjust the air flow volume.

To the downstream end of the air duct 50 for main burners, the wind box 54 for main burners is connected. In the wind box 54 for a main burner, the main burner 12 (refer FIG. 1) is accommodated. The air supplied to the wind box 54 for the main burner is used as the combustion air of the main burner 12 .

<Operating method of boiler 10>

Next, the operation method of the boiler 10 is demonstrated. The control unit 15 adjusts the operation load of the boiler 10 by adjusting combustion by the main burner 12 and the sub-burner 13 according to the load of the use destination of the steam generated by the boiler 10 . .

When a low load less than a predetermined value is requested|required, for example, like the case where the steam turbine for cargo oil pumps is not driven, the control part 15 does not operate the main burner 12, but makes it non-operation. That is, combustion by the main burner 12 is not performed. At this time, the boiler 10 is warm-up driven by the sub-burner 13 . The control unit 15 operates only the sub-burner 13 to burn fuel oil and/or fuel gas. Thereby, without using the main burner 12 of high capacity, the boiler 10 is warmed up by the sub-burner 13 of a small capacity, and fuel consumption is suppressed, For example, when driving of a steam turbine becomes necessary, etc. By operating the burner 12, steam can be supplied from the boiler 10 quickly.

When a high load of a predetermined value or more is requested|required, for example, when driving of the steam turbine for cargo oil pumps is required, for example, the control part 15 increases the load of a steam turbine (operating load required for the boiler 10). increase), the supply amount of fuel oil and/or fuel gas to the main burner 12 is gradually increased. In this way, when performing combustion using only the main burner 12, the control part 15 supplies air from the air fan 44 for sub-burners so that the sub-burner 13 may be cooled. At this time, fuel oil and fuel gas are not supplied to the sub-burner 13 . The control part 15 controls the air fan 44 for sub-burners so that the pressure in the wind box 40 for sub-burners becomes higher than the pressure in the combustion vessel 11.

The air supplied to the wind box 40 for sub-burners is supplied to the vicinity of the lower end of the flame F1 formed by the main burner 12 after cooling the sub-burner 13 . As a result, the NOx production amount of combustion by the main burner 12 is reduced by cooling the flame in the vicinity of the lower end of the flame F1.

<Operation in case of failure of air fan 44 for sub-burner>

When the air fan 44 for sub-burners fails and air cannot be supplied to the wind box 40 for sub-burners, the following operation|movement is implemented.

When the control unit 15 detects a failure of the sub-burner air fan 44 , the control unit 15 operates the on-off valve 49 provided in the air supply pipe 48 from fully closed to fully opened. Thereby, a part of the air supplied from the air fan 52 for main burners is supplied to the wind box 40 for sub-burners through the air supply pipe 48 and the air duct 42 for sub-burners. At this time, the control unit 15 operates the damper 46 from fully open to fully closed. Thereby, the backflow of air into the air fan 44 for sub-burners is prevented. In addition, the failure of the air fan 44 for sub-burners can be detected by monitoring the fan rotation speed, etc.

According to this embodiment, the following effects are exhibited.

A sub-burner 13 is provided on the downstream side of the flame F1 formed by the main burner 12 . For this reason, when the main burner 12 is in operation and at the time of the non-operation of the sub-burner 13, if the combustion air is not supplied to the sub-burner 13, the flame F1 by the main burner 12 There is a possibility that the sub-burner 13 may be damaged by the radiant heat caused by the Therefore, even when the sub-burner 13 is not in operation, air is supplied from the sub-burner air fan 44 to cool the sub-burner 13 . Moreover, since air was supplied so that the pressure in the wind box 40 for sub-burners may become higher than the pressure in the combustion vessel 11, the sub-burner 13 and the wind fan for sub-burners with respect to the combustion chamber 24 in a pressurized state. (40) can be sealed. Thereby, when the pressure in the wind box 40 for sub-burners is lower than the pressure in the combustion vessel 11, the possibility that the combustion gas of the main burner 12 penetrates into the sub-burner 13 (backflow) can be avoided.

The air supply pipe 48 was used to supply air from the air fan 52 for a main burner to the wind box 40 for sub-burners. Thereby, even if the air fan 44 for sub-burners fails, cooling air can be supplied to the wind box 40 for sub-burners by any chance.

In addition, it is not limited to the failure of the sub-burner air fan 44, and when the amount of air supplied from the sub-burner air fan 44 is insufficient, the sub-burner wind blow 40 from the main burner air fan 52. may be supplied with air.

The damper 46 was provided at the outlet of the air fan 44 for sub-burners. Accordingly, by closing the damper 46 when the sub-burner air fan 44 is stopped, the air induced from the main burner air fan 52 through the air supply pipe 48 is transferred to the sub-burner air fan ( 44) to prevent backflow.

[Second embodiment]

Next, a second embodiment of the present invention will be described. This embodiment differs from 1st embodiment in that it is provided with the structure which cools the sub-burner 13 using steam. Therefore, below, a different structure is demonstrated with respect to 1st Embodiment.

The system which supplies fuel oil to the oil injection nozzle 13a (refer FIG. 3) provided in the sub burner 13 by FIG. 5 is shown. A fuel oil supply path 60 and a vapor supply path (cooling vapor supply part) 62 are connected to the oil injection nozzle 13a.

An oil tank (not shown) and an oil supply pump are connected to the upstream side of the fuel oil supply path 60 . A control valve 64 is formed in the fuel oil supply path 60 . The control valve 64 is controlled by the control unit 15 .

A vapor source (not shown) is connected to the upstream side of the vapor supply path 62 . The vapor supply path 62 is branched into the atomized vapor supply path 62a and the purge vapor supply path 62b.

The atomized vapor supply path 62a is connected to the oil injection nozzle 13a. A control valve 66 and a check valve 67 controlled by the control unit 15 are provided in the atomized vapor supply path 62a. The vapor supplied from the atomized vapor supply path 62a is originally used in order to atomize fuel oil. However, in this embodiment, it can be used as cooling vapor|steam.

The downstream end of the purge vapor supply path 62b is connected to the fuel oil supply path 60 . The control valve 68 and the check valve 69 controlled by the control part 15 are formed in the purge vapor|steam supply path|route 62b. The vapor supplied from the purge vapor supply path 62b is originally used in order to purge the path|route through which fuel oil flows with vapor|steam. However, in this embodiment, it can be used as cooling vapor|steam.

Steam cooling of the sub-burner 13 according to the present embodiment is performed as follows.

When the control valve 64 of the fuel oil supply path 60 is closed and the supply of fuel oil is stopped, the sub-burner 13 becomes inactive. At this time, when the main burner 12 is in operation, the control part 15 uses the vapor|steam supply path 62 to inject vapor from the oil injection nozzle 13a. Specifically, the control valve 66 of the atomized vapor supply path 62a is opened, and the control valve 68 of the purge vapor supply path 62b is opened, and the steam is injected into the oil spray nozzle 13a. ) leads to The sub-burner 13 is protected from radiant heat radiated from the flame F1 formed in the combustion chamber 24 by being sprayed with steam from the oil injection nozzle 13a.

By spraying cooling steam radially (shad-shaped) from the tip of the oil spray nozzle 13a, a swirler or a gas nozzle mounted on the oil spray nozzle 13a is easily damaged by the radiant heat of the flame of the main burner 12. The point can be blocked with cooling steam, so that the sub-burner 13 can be more effectively protected.

According to this embodiment, the following effects are exhibited.

Since oil is not supplied to the oil jet nozzle 13a of the sub-burner 13 during non-operation, the oil jet nozzle 13a is a part of the cooling steam supply unit, and cooling steam is discharged from the oil jet nozzle 13a. was to supply. Since the oil injection nozzle 13a injects cooling vapor|steam toward the inside of the combustion chamber 24 from the front-end|tip of the sub-burner 13, it can protect the sub-burner 13 effectively from radiant heat.

By injecting steam from the oil injection nozzle 13a of the secondary burner 13, steam can be supplied to the downstream side of the flame F1 of the main burner 12. Thereby, the temperature of the flame F1 can be reduced, and thermal NOx can be reduced. Also, if steam is supplied to the source of the flame F1, mixing of fuel and air is inhibited and combustion becomes unstable. On the downstream side of the flame F1 (the tip of the flame F1), the combustion reaction is close to the end, and since a lot of air is not required, there is no fear that combustion becomes unstable.

Further, instead of jetting steam from the oil jet nozzle 13a or in addition to jetting steam from the oil jet nozzle 13a, steam from the gas jet nozzle 13b (see Fig. 3) of the sub-burner 13 is may be supplied. Thereby, the cooling vapor can be supplied from the gas injection nozzle 13b by making the gas injection nozzle 13b a part of a cooling vapor|steam supply part. Since the gas injection nozzle 13b injects cooling vapor|steam toward the inside of the combustion chamber 24 from the front-end|tip of the sub-burner 13, it can protect the sub-burner 13 effectively from radiant heat. Further, the gas injection nozzle 13b protruding into the combustion chamber 24 can be effectively cooled.

[Third embodiment]

Next, a third embodiment of the present invention will be described. This embodiment differs from 1st embodiment in that it is provided with the structure which cools the sub-burner 13 using steam. Therefore, below, a different structure is demonstrated with respect to 1st Embodiment.

As shown in FIG. 6, the vapor|steam ring nozzle (steam supply nozzle) 72 is formed in the wind box 40 for sub-burners. The steam ring nozzle 72 is connected to the steam source which is not shown in figure, and injects steam toward the inside of the combustion chamber 24 from the wind fan 40 for sub-burners. As shown in FIG. 7, the vapor ring nozzle 72 has a ring-shaped pipe, and the some injection hole 72a is formed with respect to this pipe at predetermined intervals. The vapor ring nozzle 72 is provided so as to surround the base end of the sub-burner 13 .

According to this embodiment, the following effects are exhibited.

In the wind chamber 40 for secondary burners, the vapor ring nozzle 72 was provided as a part of a cooling vapor|steam supply part. Thereby, the sub-burner 13 accommodated in the wind box 40 for sub-burners can be cooled.

Moreover, since cooling steam can be supplied to the whole sub-burner 13 by the steam ring nozzle 72, a point easily damaged by the flame of the main burner 12, such as the swirler and the gas injection nozzle 13b. can be effectively cooled. Moreover, the flame cooling effect by steam injection is also wide and NOx reduction becomes possible.

In addition, since a path for supplying the cooling steam can be formed separately from the oil injection nozzle 13a or the gas injection nozzle 13b of the sub-burner 13, the cooling steam is supplied regardless of the operation of the sub-burner 13. can supply By blowing in steam at the time of operation of the sub-burner 13, NOx reduction of the sub-burner 13 itself becomes possible.

Further, by supplying steam from the steam ring nozzle 72 toward the inside of the combustion chamber 24 , steam can be supplied to the downstream side of the flame F1 of the main burner 12 . Thereby, the temperature of the flame F1 can be reduced, and thermal NOx can be reduced.

10 ; Boiler
11 ; combustion vessel
12 ; main burner
13 ; sub burner
13a; oil spray nozzle
13b; gas injection nozzle
14 ; evaporator
15 ; control
22 ; gas outlet
24 ; combustion chamber
26 ; water drum
27 ; steam drum
29 ; bulkhead
33 ; exhaust room
40 ; wind blower for sub burner
42 ; Air duct for sub-burner
44 ; Air fan for sub-burner (air supply means)
46 ; damper
48 ; air supply pipe
49 ; on-off valve
50 ; Air duct for main burner
52 ; Air fan for main burner
54 ; wind blower for main burner
60 ; fuel oil supply route
62 ; steam supply path
62a; Atomized steam supply route
62b; Purge steam supply path
64 ; control valve
66 ; control valve
67; check valve
68; control valve
69 ; check valve
72 ; Steam Ring Nozzle (Steam Supply Nozzle)
AR1 ; air for sub-burner
F1, F2 ; flame
G ; combustion gas

Claims (9)

a combustion vessel forming a combustion chamber;
a main burner formed in the combustion vessel;
a secondary burner formed in the combustion vessel and formed on the downstream side of the flame formed by the main burner and having a smaller capacity than the main burner;
a wind vane for a sub-burner mounted on the combustion vessel while accommodating the sub-burner;
an air supply means for supplying air to the wind chamber for the sub-burner;
and a control unit for controlling the air supply means,
The control unit, when the main burner is in operation and when the sub-burner is not in operation, driving the air supply means, the boiler. The method of claim 1,
The control unit, the boiler to control the air supply means so that the pressure in the wind chamber for the secondary burner is higher than the pressure in the combustion vessel. The method of claim 1,
A boiler having a cooling steam supply unit for supplying cooling steam for cooling the sub-burner. 4. The method of claim 3,
The sub-burner is provided with an oil injection nozzle for injecting oil fuel into the combustion chamber as a fuel for combustion,
The oil injection nozzle is a part of the cooling steam supply unit. 4. The method of claim 3,
A steam supply nozzle is formed as a part of the cooling steam supply unit in the wind chamber for the sub-burner. 5. The method according to claim 3 or 4,
The sub-burner is provided with a gas injection nozzle for injecting a gas fuel as a fuel for combustion into the combustion chamber,
The gas injection nozzle is a part of the cooling steam supply unit. 4. The method of claim 3,
The cooling steam supply unit, for supplying cooling steam toward the downstream side of the flame formed by the main burner, boiler. 3. The method according to claim 1 or 2,
A windshield for the main burner mounted on the combustion vessel while accommodating the main burner,
An air fan for the main burner for supplying air to the wind chamber for the main burner,
A boiler having an air supply pipe for supplying air from the air fan for the main burner to the wind chamber for the sub-burner. 9. The method of claim 8,
A damper for opening and closing a flow path is formed at an outlet of the air supply means.

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