JP2012057913A - Steam supply device of boiler deposit removing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a steam supply system passage warm so that drainage is not contained in steam supplied to a boiler deposit removing device such as a soot blower and a deslagger disposed in a boiler, and to effectively use the steam after the steam supply system passage is kept warm.SOLUTION: A downstream pipe 10, connected to each boiler deposit removing device 2 of the steam supply system passage 1 to supply the steam from the boiler to each boiler deposit removing device 2 while adjusting its pressure to set pressure is connected to an intermediate pressure pipe 12 communicating with an intermediate pressure steam use device 11 using the steam of intermediate pressure lower than the set pressure, and a flow rate setting means 14 for setting a flow rate of the steam flowing from each downstream pipe 10 toward the intermediate pressure pipe 12 is disposed in each downstream pipe 10 so that an internal temperature of each downstream pipe 10 reaches a set temperature higher than a saturation temperature of the steam of the set pressure.

Description

  The present invention can maintain the steam supply path so that the steam supplied to the boiler deposit removing device such as the soot blower or the deslager provided in the boiler does not contain drain, and after the steam supply path is kept warm It is related with the steam supply apparatus of the boiler deposit removal apparatus which used effectively the steam of this.

  Conventionally, in a thermal power plant or the like, water is evaporated by a boiler using coal (pulverized coal) or the like as fuel to generate high-temperature and high-pressure steam, and a turbine is driven by this steam to generate power. As described above, when coal or the like is used as fuel for the boiler, the clinker is attached to the furnace wall tube of the boiler, and the heat exchanger disposed in the boiler or the rear heat transfer section at the rear of the boiler is provided. Soot adheres to the heat transfer tube surface and wall surface of the heat exchange section. When such clinker or soot adheres, there is a problem that the heat transfer efficiency with respect to water or steam flowing in the pipe by the high-temperature gas is lowered and the heat recovery of the boiler is deteriorated.

  In order to cope with this problem, conventionally, a deslagger for removing clinker generated in a furnace wall tube by injecting high-temperature and high-pressure steam generated in a boiler, or for removing soot generated in a heat transfer tube, etc. Boiler deposit removal devices called soot blowers are installed at multiple locations on the boiler. The boiler deposit removal device is a boiler furnace wall tube that is inserted into a boiler or a rear heat transfer section while rotating a rod-shaped device having a steam injection port on its peripheral surface around the shaft center, and using the steam jetted from the steam injection port. The clinker adhering to the wall, the heat transfer tube, and the wrinkles adhering to the wall surface are washed away.

  Each boiler deposit removing device is connected to a steam supply system that adjusts the high-temperature and high-pressure steam generated in the boiler to a predetermined pressure and opens and closes at the inlet of each boiler deposit removing device. Steam is injected by opening the valve. In the boiler deposit removing device, conventionally, the clinker and soot are removed by injecting steam of about 2 ton / hr for about 2 to 3 minutes once a day.

  On the other hand, when the steam is not jetted by the boiler deposit removing device, the on-off valve is closed to pause the boiler deposit removing device, but at this pause, the temperature of the steam supply path decreases. As a result, the steam in the steam supply system is drained one after another, and the drain is stored so as to fill the steam supply system. Therefore, if the steam is ejected again by the boiler deposit removing device in this state, the stored cold drain is jetted from the boiler deposit removing device, and this drain together with the particles in the gas, There may be a problem of erosion by colliding with the heat transfer tube, or a cold drain may hit the high temperature furnace wall tube or heat transfer tube, causing cracks in the furnace wall tube or heat transfer tube due to thermal shock.

  In order to avoid such a problem, first, steam is circulated through the steam supply system for about 10 minutes so that drain is not guided to the boiler deposit removing apparatus when the steam is injected by the boiler deposit removing apparatus. The work of warming up is performed by warming the steam supply system by discharging it outside the system. For this warm-up, for example, steam of 2.5 ton / hr or more may be used. Moreover, the steam used for warming has high temperature and high pressure (for example, 230 ° C., 2.5 MPa), and the steam used for warming is pure water used for steam generation in a boiler. Although it has the same high water quality, it is generally collected in a blow tank and drained. However, because a large amount of steam used for warming is discarded in this way, it has become extremely uneconomical.

  In order to cope with such conventional problems, it is unnecessary to warm up the steam supply system by constantly supplying steam to the steam supply system and keeping it warm. There is a device that uses steam to make effective use of steam by sending it to a drain tank or a condenser (see Patent Document 1).

  In Patent Document 1, the flow rate adjusting means is provided to adjust the pressure of the steam supplied to the low pressure device to 0.65 MPa, for example.

JP 2005-172400 A

  However, in the apparatus described in Patent Document 1, steam is constantly supplied to the steam supply system, and at this time, the pressure of the steam sent to the low-pressure device or the like is adjusted by, for example, 0.65 MPa. If the steam temperature in the steam supply system is below the saturated steam temperature because the pressure is controlled regardless of the steam temperature, the steam temperature is below the saturated steam temperature. In some cases, drain is stored in the steam supply system, and this drain is sprayed from the soot blower to the furnace wall tube and the heat transfer tube as in the conventional case, which may cause erosion and cracking problems.

  In recent years, low-quality coal has been used as a fuel. For this reason, the amount of deposits such as clinker and soot has increased, and soot blowers have been operated frequently. In addition, since the heat collection status of each part of the boiler corresponds to the amount of deposits, optimal soot blowers that operate the soot blower of each part of the boiler according to the heat collection status are being implemented. . As described above, if the operation of operating the soot blower at the necessary location with the optimum soot blower is frequently performed, the pressure in the steam supply system will fluctuate. There is a problem that a problem that drain is stored in the supply path is likely to occur.

  Further, in Patent Document 1, the flow rate of the steam supplied to the low pressure device is adjusted by providing the flow rate adjusting means. However, the provision of the flow rate adjusting means in a bad environment in the vicinity of the boiler easily causes a problem of failure. Furthermore, there is a problem that maintenance is also required.

  In Patent Document 1, 0.65 MPa steam that has passed through the soot blower path is sent to a device that uses low-pressure steam, a drain tank, or a condenser, but the pressure has decreased to 0.65 MPa. The location where steam is used is limited, and its use effect is small. When it is supplied to a drain tank or condenser, its heat and pressure are not used effectively and discarded. It was a disadvantage.

  The present invention has been made in view of the above-described problems, and keeps the steam supply path warm so that the steam supplied to the boiler deposit removing device such as a soot blower or a deslagger provided in the boiler does not contain drain, and the steam It is an object of the present invention to provide a steam supply device for a boiler deposit removing device that makes effective use of steam after the supply system is kept warm.

  In the present invention, the downstream piping connected to each boiler deposit removing device of the steam supply system that adjusts the steam from the boiler to the set pressure and supplies it to each boiler deposit removing device is lower than the set pressure. It is connected to an intermediate pressure pipe that communicates with an intermediate pressure steam using device that uses an intermediate pressure steam, and the internal temperature of each downstream pipe is set higher than the saturation temperature of the set pressure steam in each of the downstream pipes. The present invention relates to a steam supply device of a boiler deposit removing device, characterized by comprising a flow rate setting means for setting a flow rate of steam from each downstream pipe to an intermediate pressure pipe so as to reach a temperature.

  In the steam supply device of the boiler deposit removing device, it is preferable that the flow rate setting means is a needle valve.

  According to the steam supply device of the boiler deposit removal apparatus of the present invention, the internal temperature of each downstream pipe is lower than the saturation temperature of the steam at the set pressure in each downstream pipe of each boiler deposit removal apparatus in the steam supply system. Since there is provided a flow rate setting means for setting the flow rate of steam from each downstream pipe to the intermediate pressure pipe so as to reach a high set temperature, the temperature inside each downstream pipe does not drop below the saturation temperature of the steam. In addition, it is possible to reliably prevent the problem that drain is ejected from the boiler deposit removing device, and to effectively prevent the problem that erosion, cracks, and the like occur in the furnace wall tube and the heat transfer tube.

  Further, since the downstream pipe is connected to an intermediate pressure pipe connected to an intermediate pressure steam using apparatus that uses an intermediate pressure steam lower than the set pressure, the temperature and pressure of the steam taken out from the downstream pipe is wasted. Therefore, it can be used by supplying it to the intermediate pressure steam use device without lowering the temperature, and it is advantageous in that it becomes thermally advantageous.

It is a block diagram which shows one Example of the steam supply apparatus of the boiler deposit removal apparatus which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of a steam supply device of a boiler deposit removing apparatus according to the invention. In the figure, 1 is an outlet of a rear heat transfer section 3a (not shown) or a reheat steam pipe ( CRP) 3b is a steam supply system that constitutes the steam supply device of the present invention in which the steam from the steam extraction section 3 is guided, and 2 is a deslagger for removing clinker generated in the furnace wall tube of the boiler. 2a and a soot blower 2b for removing soot generated in a heat transfer tube or the like. The boiler deposit removing apparatus 2 is disposed in the air preheater 4 or the like in addition to the necessary parts of the boiler. ing.

  The steam extraction part 3 is provided with a pressure regulating valve 5, and the pressure of the steam supplied to the boiler deposit removing device 2 is set to a set pressure of 2.5 MPa, for example. Steam from the steam supply line 1 is branched and guided to a plurality of block pipes 6, and each block pipe 6 is further branched and guided to a plurality of branch pipes 7. 7 is connected to the boiler deposit removing device 2 by an introduction pipe 9 having an on-off valve 8.

  Each downstream pipe 10 downstream of the position where the introduction pipe 9 is connected in each branch pipe 7 is connected to an intermediate pressure pipe 12 that communicates with an intermediate pressure steam using device 11 that uses an intermediate pressure steam. The intermediate pressure steam using device 11 includes an aerator heating device, a condenser demineralizer heating device, a turbine seal, a steam heater, a steam converter, a heavy oil conveyance pipe heating device, or a heating device provided on the turbine side. In the present invention, steam of, for example, about 0.7 to 1.5 MPa used in these apparatuses is used as intermediate pressure steam.

  Each of the downstream pipes 10 is provided with a thermometer 13 for detecting the temperature of the steam in each of the downstream pipes 10 and a flow rate setting comprising a needle valve or the like that manually sets the flow rate of the steam flowing through the downstream pipe 10. Means 14 are provided.

  Therefore, in the flow rate setting means 14, the temperature detected by the thermometer 13 is set to a set temperature that is higher (for example, 2 to 3 ° C. higher) than the steam saturation temperature with respect to the set pressure set by the pressure control valve 6. The flow rate of steam from each downstream pipe 10 toward the intermediate pressure pipe 12 is set by a needle valve and fixed in that state.

  In the figure, 15 is a drain blow tank, and when the steam in the intermediate pressure pipe 12 becomes excessive with respect to the amount of steam used in the intermediate pressure steam using device 11, the regulating valves 16 and 17 are operated. Excess steam can be discharged to the drain blow tank 15.

  The operation of the above embodiment will be described below.

  The steam taken out from the steam take-out part 3 is set to a set pressure of 2.5 MPa by the pressure regulating valve 5. Further, the steam whose pressure is set by each pressure regulating valve 5 is led to a plurality of block pipes 6 and branch pipes 7, and then led from the downstream pipe 10 to the intermediate pressure pipe 12 and supplied to the intermediate pressure steam using device 11. Is done.

  At this time, the flow rate setting means 14 provided in each of the downstream pipes 10 is based on the temperature detected by the thermometer 13 that detects the temperature of the steam in each of the downstream pipes 10, The flow rate of the steam from each downstream pipe 10 to the intermediate pressure pipe 12 is set in advance so that the set temperature is higher than the saturation temperature. For example, when the saturation temperature of 2.5 MPa steam is 225 ° C., the flow rate of the steam toward the intermediate pressure pipe 12 so that the flow rate setting means 14 is maintained at a set temperature that is 2 to 3 ° C. higher than 225 ° C. Is set.

  Accordingly, the intermediate pressure steam is supplied to the intermediate pressure pipe 12 while being lower than the set pressure but maintained at a relatively high pressure and temperature. Used for.

  As described above, each downstream pipe 10 of the boiler deposit removal apparatus 2 includes a thermometer 13 and a flow rate setting unit 14, and the internal temperature of each downstream pipe 10 is higher than the saturated temperature of the steam at the set pressure. Since the flow rate of the steam from each downstream pipe 10 to the intermediate pressure pipe is set so as to become, the temperature inside each downstream pipe 10 does not drop below the saturation temperature of the steam, and the steam supply path 1 is always The temperature is kept above the saturation temperature.

  Therefore, when the on-off valve 8 of the introduction pipe 9 connected to the boiler deposit removing apparatus 2 is opened, steam with a set pressure is injected from the boiler deposit removing apparatus 2 and the clinker generated in the furnace wall pipe. And soot such as heat transfer tubes are removed. At this time, since the steam supply path 1 is kept at a temperature equal to or higher than the saturation temperature as described above, a problem that drain is injected from the boiler deposit removing device 2 can be reliably prevented. Therefore, it is possible to reliably prevent problems such as erosion and cracks occurring in the furnace wall tube and heat transfer tube due to the injection of drain from the boiler deposit removing device 2.

  Further, the downstream pipe 10 is connected to an intermediate pressure pipe 12 communicating with an intermediate pressure steam using device 11 that uses an intermediate pressure steam lower than a set pressure, and the temperature and pressure of the steam taken out from the downstream pipe 10 is wasted. Since it is used by supplying it to the intermediate pressure steam using apparatus 11 without lowering it, it becomes thermally effective.

  Further, the flow rate setting means 14 may set the flow rate in advance so that the internal temperature of the downstream pipe 10 is higher than the saturation temperature of the steam at the set pressure, and does not require flow rate adjustment. There is an advantage that the problem of occurrence of the problem can be reduced and the maintenance work can be reduced.

  In addition, the steam supply apparatus of the boiler deposit removal apparatus of this invention is not limited only to the above-mentioned Example, Of course, various changes can be added within the range which does not deviate from the summary of this invention.

DESCRIPTION OF SYMBOLS 1 Steam supply system 2 Boiler deposit removal apparatus 6 Pressure control valve 10 Downstream piping 11 Intermediate pressure steam using apparatus 12 Intermediate pressure piping 13 Thermometer 14 Flow rate setting means

Claims (2)

  Steam at an intermediate pressure lower than the set pressure is connected to each boiler deposit removing device in a steam supply path for adjusting the steam from the boiler to a set pressure and supplying the boiler deposit removing device to each boiler deposit removing device. Is connected to an intermediate pressure pipe communicating with the intermediate pressure steam using device, and the internal temperature of each downstream pipe is set to a set temperature higher than the saturation temperature of the steam at the set pressure in each downstream pipe. A steam supply device for a boiler deposit removing apparatus, further comprising a flow rate setting means for setting a flow rate of steam from each downstream pipe to the intermediate pressure pipe.   The steam supply device for a boiler deposit removing device according to claim 1, wherein the flow rate setting means is a needle valve.

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