JPH08189630A - Soot blower - Google Patents

Abstract

PURPOSE: To achieve a cooling of a lance tube extending into a furnace effectively in a soot blower while preventing the breakage of heat transfer tubes desired to remove soot by reducing a flow rate of steam. CONSTITUTION: A water supplying device (a water purifying tank 24, a press-fit pump 23 and a water injection pipe 11) is provided to inject water into steam to be supplied to a lance tube 6 adapted to jet out the steam supplied at a nozzle 8 provided at the tip part thereof and the lance tube 6 is cooled by an evaporation latent heat of the water.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soot blower applied to a coal fired boiler or the like.

[0002]

2. Description of the Related Art FIG. 3 shows a conventional soot blower. A soot blower is a device that blows off soot (soot) adhering to the heat transfer tubes in the boiler with a high-pressure, high-speed steam flow. Reference numeral 1 is a steam supply pipe, 2 is a head valve connected to the steam supply pipe 1, and the head valve 2 is provided with an operating rod 3. By moving the operating rod 3 up and down, the stop and flow of steam are controlled. . 5
Is a feed pipe, one end of which is connected to the outlet of the head valve 2 and the other end of which is inserted into a lance tube 6 which penetrates the boiler furnace wall 10. Reference numeral 7 denotes a seal device between the lance tube 6 and the feed tube, which connects the lance tube 6 along the outer circumference of the feed pipe 5 so as to be slidable / rotatable in the direction shown by an arrow 9 and also to connect the lance tube 6 and the feed pipe. Prevents steam leaks during the period 5.

The other end (tip) of the lance tube 6 is closed, and a nozzle 8 is provided at this end, and a supersonic vapor jet 4 is jetted from the nozzle 8 and provided in the furnace. The soot adhering to the outer circumference of the heat transfer tube 11 is blown off by the steam jet 4. Further, 12 is a carriage for sliding / rotating the lance tube 6, and 13 is a rail through which the carriage 12 passes.

[0004]

In the conventional sootblower, the amount of steam used is mainly determined from the following two points. (1) Soot removal capacity: The amount of steam used is determined by the soot removal capacity in the middle and low temperature range of the boiler. (2) Cooling capacity: In the high temperature region of the boiler, the lance tube is heated by radiation and convection from the gas in the furnace.
To cool this, it is necessary to increase the amount of steam.

When the cooling capacity is sufficient as described above, there is a problem that the steam jet flow is too strong, which may cause erosion in the heat transfer tube, and the amount of steam used also increases, resulting in high running cost.

The present invention is intended to solve the above problems, and it is an object of the present invention to reduce the amount of steam used in the high temperature range of a conventional sootblower and prevent the occurrence of problems such as damage to the heat transfer tube.

[0007]

According to the present invention, there is provided a soot blower equipped with a lance tube for ejecting steam supplied from a steam supply section from a nozzle provided at a tip portion of the soot supply section to the lance tube. It is characterized in that a water supply device for injecting water into the steam for mixing is provided.

[0008]

In the present invention, water is injected and mixed into the steam supplied from the steam supply section to the lance tube, so that the flow in the lance tube becomes a spray flow. This spray flow is heated and evaporated when flowing through the lance tube. Since the lance tube is cooled by this, it is not necessary to cool the lance tube by flowing a large amount of steam to increase the flow velocity in the tube as in the conventional case, and the supplied steam flow rate is greatly reduced. Further, as a result, the amount of steam jet from the nozzle of the lance tube becomes an appropriate amount, and damage to the heat transfer tube is prevented.

[0009]

FIG. 1 shows an embodiment of the present invention. Reference numeral 1 is a steam supply pipe, 2 is a head valve provided at an end of the steam supply pipe 1, and 3 is an operating rod of the head valve. By moving the operating rod 3 up and down, the stop / flow of steam is controlled. Reference numeral 5 denotes a circular tubular feed pipe, and a nozzle 22 connected to the outlet of the head valve 2 is arranged in one end of the feed pipe 5. The steam supply pipe 1, the head valve 2,
The actuating rod 3 of the head valve and the nozzle 22 constitute a steam supply unit.

The feed pipe 5 on the outer circumference of the nozzle 22.
An upper end of a water injection pipe 21 having a press-fitting pump 23 is connected to the portion of FIG. 4, and a lower end of the water injection pipe 21 is arranged in a water purification tank 24 for removing evaporation residual solids from the supply water. . Reference numeral 25 is water to be injected in the water purification tank 24. Reference numeral 26 is a venturi mechanism provided in a portion of the feed pipe 5 on the downstream side of the nozzle 22 for mixing steam and water.

Reference numeral 6 denotes a circular tubular lance tube into which the other end of the feed pipe 5 is inserted. The lance tube 6 extends through the boiler furnace wall 10 into the boiler furnace. A seal device 7 is provided at one end of the lance tube 6 and seals the feed pipe 5 and the lance tube 6 so that the feed pipe 5 and the lance tube 6 can move relative to each other. Feed pipe 5 so that it can move axially and circumferentially
Are arranged around. The tip of the lance tube 6 inside the boiler furnace is closed, and a nozzle 8 is provided near the tip. The lance tube 6 is driven by a drive device (not shown) via a mechanism similar to the conventional soot blower shown in FIG. 3, and as shown by an arrow 9, a shaft is provided along the feed pipe 5 via a seal device 7. It moves in the direction and rotates around the feed pipe 5.

The press-fitting pump 23 feeds the water 25 in the purified water tank 24 having a flow rate proportional to the axial movement length of the lance tube 6, that is, the insertion length of the lance tube 6 into the furnace by a mechanism not shown. It is designed to be supplied within 5. Reference numeral 11 in FIG. 1 is a heat transfer tube provided in the furnace.

In this embodiment, the high-speed steam supplied from the steam supply pipe 1 enters the lance tube 6 from the feed pipe 5, and the supersonic steam jet 4 from the nozzle 8 of the lance tube 6 enters the furnace. Erupted. The water 25 stored in the water purification tank 24 is sucked by the pump 23 and then pressure-increased, and the water 25 is injected from the nozzle 22 into the feed pipe 5 into which the high-speed vapor flow is flowing and mixed. The high-speed steam flow is throttled in the Venturi mechanism 26 provided in the feed pipe 5 to be further accelerated, and at the same time, water is sucked to promote mixing with the steam. After passing through the venturi mechanism 26, the steam and water are completely mixed to form a substantially uniform spray flow.
This spray flow flows into the lance tube 6, and the water droplets in the spray are contact-heated and evaporated to cool the lance tube 6 by evacuating latent heat of evaporation from the lance tube 6. Since the flow in the lance tube 6 is in a turbulent state and the mixing is sufficient, the water droplets in the lance tube 6 uniformly and gradually evaporate.

Since the amount of heat received by the lance tube 6 in the furnace is substantially proportional to the length of insertion in the furnace, the flow rate of the water supplied by the press-fitting pump 23 is proportional to the length of insertion of the lance tube 6 in the furnace as described above. By controlling, the amount of heat received by the lance tube 6 and the amount of latent heat of vaporization of water can be substantially balanced, and the temperature of the lance tube 6 can be kept substantially constant.

FIG. 2 shows the elapsed time, the steam flow rate, and the supply water flow rate during the operation of the soot blower. Since the conventional soot blower needs to flow steam at high speed in the lance tube for heat removal, the steam flow rate needs to be excessively higher than the amount required for soot removal, as indicated by line A in FIG. However, in the present embodiment, the cooling of the lance tube 6 is performed by the latent heat of vaporization of water supplied at the flow rate indicated by the line C in FIG. 2, so the supply steam flow rate is maintained at the injection pressure required for soot removal, The amount is sufficient to generate a spray flow and to act as a flow power, and a part of the steam required for soot removal is generated by water evaporation in the lance tube 6. Therefore, as shown by the line B in FIG. 2, the required steam flow rate can be significantly reduced.

On the other hand, considering the damage to the heat transfer tube, since the steam flow rate in the conventional soot blower is too large, erosion may occur, but in this embodiment, the cooling and soot removal of the lance tube 6 are as described above. Therefore, it is not necessary to increase the steam flow rate, and damage to the heat transfer tube 11 is inevitably avoided.

As described above, in this embodiment, the water supplied to the lance tube 6 is added to the water purification tank 24 and the press-fitting pump 23.
Water is injected from the water supply device including the water injection pipe 21 and mixed, and the steam and water are completely mixed in the Venturi mechanism 26 to form a uniform spray flow, which is made to flow in the lance tube 6. Because it is set to Lance tube 6
Is cooled by the latent heat of vaporization of water in the spray flow, so that the lance tube 6 can be effectively cooled and the supply steam flow rate can be reduced to prevent the heat transfer tube 11 from being damaged.

Further, since the flow rate of the water injected into the feed pipe 5 is controlled in proportion to the length of the lance tube 6 inserted in the furnace, the amount of heat received by the lance tube 6 and the latent heat of vaporization of water are almost equal to each other. The temperature of the lance tube 6 can be kept substantially constant by balancing.

[0019]

Since the soot blower of the present invention is provided with a water supply device for injecting water into the steam supplied from the steam supply section to the lance tube and mixing it, the lance tube is effectively cooled by the latent heat of vaporization of water. It is possible to reduce the running cost by reducing the flow rate of steam supplied at the same time, and to prevent the heat transfer tube from being damaged.

[Brief description of drawings]

FIG. 1 is an overall view of an embodiment of the present invention.

FIG. 2 is a graph showing a steam flow rate and a supply water flow rate of the soot blower of the same example and the related art.

FIG. 3 is an overall view of a conventional sootblower.

[Explanation of symbols]

 1 steam supply pipe 2 head valve 3 head valve operating rod 4 steam jet 5 feed pipe 6 lance tube 7 sealing device 8 nozzle 9 moving direction of lance tube 10 boiler furnace wall 11 heat transfer pipe 12 carriage 13 rail 21 water injection pipe 22 nozzle 23 Press-fitting pump 24 Water purification tank 25 Water 26 Venturi mechanism

Claims (1)

[Claims] 1. A soot blower having a lance tube for ejecting steam supplied from a steam supply section from a nozzle provided at a tip portion, wherein water is injected into steam supplied to the lance tube from the steam supply section. A soot blower characterized by having a water supply device that mixes it in by mixing.