JP2014084744A - Dust adhesion prevention device for stator blade of furnace top pressure recovery turbine - Google Patents

Abstract

Dust adhering to a stationary blade can be reliably removed with a small amount of water, and stable and efficient operation can be continued even during long-term continuous operation.
A furnace top pressure recovery turbine 10 that is used in a furnace top pressure recovery turbine power generation facility and that is rotated and connected by a blast furnace gas supplied from a blast furnace and connected to a generator, and a stationary blade of the turbine. In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine, which includes a water supply device 30 for supplying water for water washing through the water supply passage 43, the turbine is disposed upstream of the stationary blade. The outer peripheral wall 10a has a slit 41 extending in the circumferential direction, and this slit flows out the water supplied from the water supply device to the downstream side of the turbine and in a layered manner along the outer peripheral wall of the turbine. Let
[Selection] Figure 4

Description

  The present invention relates to an apparatus for preventing dust from adhering to a stationary blade of a furnace top pressure recovery turbine.

  Furnace top pressure recovery turbine power generation equipment used for power generation by installing a turbine in the exhaust gas passage of a blast furnace plant collects the pressure energy of the blast furnace gas generated in the blast furnace of the steel works as electric power by the turbine, It is a top pressure control system, and has recently become an extremely important facility for saving energy in steelworks and contributing to environmental conservation.

  There are two types of turbine top pressure recovery turbine power generation equipment: wet type and dry type. The wet top pressure recovery turbine power generation equipment is a furnace for driving a generator after washing the blast furnace gas from the blast furnace with a wet dust remover. It leads to a top pressure recovery turbine. On the other hand, in the dry type furnace top pressure recovery turbine power generation facility, since the blast furnace gas is dedusted without being washed with water by the dry type dust remover, the temperature of the blast furnace gas is not lowered, and the recovered power is 25 compared with the wet type. It is increased by ˜45%, and the power can be recovered efficiently.

  Since no fuel is required to drive the turbine for power generation, CO2 reduction and energy saving are extremely high. Most of the blast furnaces at domestic steelworks currently have wet or dry top pressure recovery turbine power generation. Equipment is installed.

  However, in the above-described wet furnace top pressure recovery turbine power generation facility, the blast furnace gas is washed with water by the wet dust remover, and as a result, the blast furnace gas contains steam up to a saturated state and cannot be recovered by the wet dust remover. Is accompanied. For this reason, as shown in FIG. 9, a problem arises in that a large amount of this dust adheres mainly to the rear edge portion on the convex surface (negative pressure surface) 102 of the first stage stationary blade 101 during normal operation.

  When dust adheres to the first stage stationary blade 101, the flow flowing into the first stage rotor blade 103 is disturbed, and a strong excitation force is generated for the first stage rotor blade 103. As a result, a repeated stress is generated on the moving blade 103, causing a problem that the fatigue limit of the first-stage moving blade 103 is significantly reduced. Further, there is a problem that an appropriate gas flow cannot be formed by dust, and the turbine efficiency is remarkably lowered.

  In order to perform furnace top pressure control, the first stage stationary blade is often provided with a variable angle mechanism. However, if a large amount of dust adheres to the convex surface of the first stage stationary blade as described above, the first stage stationary blade cannot be closed to its fully closed angle when fully closed, and the gas inflow to the turbine is reduced to a predetermined flow rate. This causes a problem that it cannot be reduced. In addition, there is a problem that the first stage stationary blade is caught in the dust deposit when fully closed, and excessive force acts on the blade portion and the angle variable mechanism to cause damage.

  For this reason, conventionally, during normal operation or the like, water injection is periodically performed from the inlet portion of the turbine or the upstream portion of the stationary blade, and the adhered dust is separated and removed (for example, (See Patent Document 1 and Non-Patent Document 1). For example, in the conventional water injection, water is directly injected into the gas flow path of the turbine from a plurality (for example, 20) of water injection nozzles disposed on the outer peripheral wall of the turbine case upstream of the first stage stationary blade. Has been done.

  At the same time, the applicants of the present application condensate the water contained in the blast furnace gas on the blade surface of the first stage stationary blade by circulating cooling water inside the first stage stationary blade and water-cooling the first stage stationary blade. An invention of a furnace top pressure recovery turbine that forms water droplets and / or a water film on the blade surface and thereby prevents dust from adhering to the first stage stationary blade has been disclosed (for example, see Patent Document 2).

  In addition, the applicants of the present application form a hydrophilic film on the surface of the first stage stationary blade, and even if dust adheres to the blade surface, the condensed water and the water jet during normal operation adhered to the surface of the stationary blade are attached. Water droplets form a liquid film of water between the dust and the blade surface due to the action of the hydrophilic film, and the dust can be easily peeled off, that is, the top pressure recovery with the stationary blade itself having a self-cleaning function The invention of the turbine was proposed (Japanese Patent Application No. 2011-062053).

  Further, the applicants of the present application calculated the actual differential pressure between the stationary blade inlet gas pressure detected by the stationary blade inlet pressure sensor and the stationary blade outlet gas pressure detected by the stationary blade outlet pressure sensor. Based on the pressure, water is sprayed from the water spray device to the stationary blade, that is, this actual differential pressure is constantly monitored and water is sprayed onto the stationary blade. Adhesion is automatically detected and the adhering dust can be removed reliably, and the furnace top pressure recovery turbine can be operated with the dust adhesion always kept within a certain range. An invention of a recovery turbine has also been proposed (Japanese Patent Application No. 2011-077685).

Japanese Patent Laid-Open No. 2005-214033 JP 2007-315364 A

"Furnace pressure turbine power generation facility", Toshiaki Nakamura and five others, Kawasaki Heavy Industries Technical Report No. 155, P20-P23, Kawasaki Heavy Industries, Ltd., issued in May 2004

  In this way, the conventional furnace top pressure recovery turbine performs water injection periodically from the turbine inlet and the stationary blade upstream during normal operation, etc., or removes adhering dust, or Cooling water is circulated in the first stage stationary blade to cool the first stage stationary blade, thereby condensing moisture contained in the blast furnace gas on the blade surface of the first stage stationary blade, and water droplets and / or a water film on the blade surface. To prevent dust from adhering to the first stage stationary blade. In the conventional water injection, water is directly injected into the gas flow path of the turbine from a plurality (for example, 20) of water injection nozzles disposed on the outer peripheral wall of the turbine case upstream of the first stage stationary blade. Has been done.

  However, the furnace top pressure recovery turbine, which periodically injects water from a plurality of water injection nozzles to the inlet of the former turbine and removes adhering dust, is a flow of blast furnace gas that passes through the turbine. Is very fast, and on the convex surface (negative pressure surface) of the stationary blade, the water droplets injected directly into the gas are difficult to reach on the upstream side. There is a problem that it cannot be completely removed by only regular water injection.

  As described above, it is a fact that only the conventional water spray during normal operation does not provide a sufficient effect for preventing dust from adhering to the first stage stationary blade, and repeatedly generates stress on the first stage blade described above. The problem is that the fatigue limit of the rotor blade is significantly reduced, the problem is that the proper gas flow cannot be formed and the turbine efficiency is lowered, and the gas flow into the turbine is reduced to the specified flow rate when fully closed. However, the problem that the first stage stationary blade bites into the dust deposits and causes damage to the blade portion and the like still remains unsolvable. Together with these, it is also necessary to reduce the amount of water for water washing as much as possible.

  In addition, a furnace top pressure recovery turbine that circulates cooling water inside the latter first stage stationary blade and water-cools the first stage stationary blade can be expected to have a great effect in preventing dust adhesion, while circulating the cooling water. There is a concern that the cooling water supply apparatus and the first stage stationary blade must be provided with a cooling water channel, which increases the cost.

  The present invention has been made to solve such problems, and can reliably remove dust adhering to the stationary blade with a small amount of water, and can continue stable and efficient operation even during long-term continuous operation. It is an object of the present invention to provide an apparatus for preventing dust from adhering to a stationary blade of a furnace top pressure recovery turbine.

  In order to solve the above-mentioned problems, the means employed by the present invention is a furnace that is used in a furnace top pressure recovery turbine power generation facility and that is driven by a blast furnace gas supplied from a blast furnace and is connected to a generator that is connected to the generator. In a device for preventing dust from adhering to a stationary blade of a furnace top pressure recovery turbine, comprising a top pressure recovery turbine and a water supply device for supplying water for water washing to the stationary blade of the turbine through a water supply passage The turbine has a slit extending in the circumferential direction on the outer peripheral wall portion on the upstream side of the stationary blade, and the slit supplies water supplied from the water supply device to the downstream side of the turbine and on the outer peripheral wall portion of the turbine. It is to make it flow out so that it may flow in layers along.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine of the present invention, the outer peripheral wall portion on the upstream side of the stationary blade has a slit extending in the circumferential direction, and the slit is supplied from the water supply device. Is discharged to the downstream side of the turbine and to flow in a layered manner along the outer peripheral wall portion of the turbine, so that the water discharged from the slit flows in a layered manner along the outer peripheral wall portion and reaches the stationary blade, The vanes enter the convex surface side of the stationary blade as they are, and flow in layers along the outer peripheral wall portion of the turbine mainly to the blade root portion on the outer side of the convex surface side.

  On the other hand, it is known that a secondary flow of gas flowing from the outer blade root portion to the radially inner side, that is, toward the center of the turbine is generated on the convex surface side of the stationary blade. Then, the water that has flowed in a layered manner along the outer peripheral wall of the turbine to the blade root on the outer side of the convex surface of the stationary blade is transferred to the center of the turbine from the blade root on the convex side of the stationary blade. It rides on the secondary flow and flows in a layered manner from the outer blade root to the center of the turbine on the convex blade surface, and then discharged from the center of the stationary blade to the downstream side of the turbine. Spread.

  In particular, water that has flowed in a layered manner along the outer peripheral wall of the turbine to the blade root on the outer side of the convex surface of the stationary blade is more concentrated on the rear edge of the stationary blade on the convex surface of the stationary blade where dust tends to adhere to the gas flow. Flowing. For this reason, dust adhesion which tends to occur at the rear edge of the stationary blade on the convex surface side can be extremely effectively prevented with a small amount of water, and dust already adhered can be efficiently removed.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine, it is desirable that the total opening area of the slit is larger than the total minimum sectional area of the water supply passage for supplying water from the water supply device to the slit. Thus, by forming the total opening area of the slit wider than the total minimum cross-sectional area of the water supply path for supplying water from the water supply device to the slit, the pressure of the water supplied from the water supply device is weakened The water can flow out from the slit into the turbine. Therefore, the water that has flowed out of the slit into the turbine flows in a more reliable layered manner along the outer peripheral wall portion of the turbine.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine, the slit includes a water storage section for temporarily storing water supplied from the water supply apparatus through the water supply path between the water supply path and the upstream side. The water reservoir preferably extends in the circumferential direction along the slit.

  The water supplied from the water supply device through the water supply passage is generally pressurized and supplied by a water pump or the like, but in the dust adhesion prevention device for the stationary blade of the furnace top pressure recovery turbine of the present invention, the slit is It is necessary to cause the water supplied from the water supply device to flow out to flow downstream in the turbine and in a layered manner along the outer peripheral wall of the turbine.

  Therefore, the slit is provided with a water storage section for temporarily storing water supplied from the water supply device through the water supply path between the water supply path on the upstream side, and the water storage section is arranged so as to extend in the circumferential direction along the slit. By providing, the water supplied from the water supply path can be flowed in a layered manner along the outer peripheral wall portion of the turbine without any breaks over the entire length of the slit.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine, it is desirable that the corner on the downstream side of the outer peripheral wall of the slit is subjected to R machining or chamfering. In this way, by performing R machining or chamfering on the downstream corner portion of the outer peripheral wall portion of the slit, water can be flowed from the slit along the outer peripheral wall portion of the turbine in a more reliable layered manner. it can.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine, it is desirable that the slit is disposed over the entire circumference of the outer peripheral wall. Thus, by arranging the slits over the entire circumference of the outer peripheral wall portion, it is possible to efficiently prevent the dust from adhering to all the stationary blades at that stage.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine, it is desirable that the slit is continuous over the entire circumference of the outer peripheral wall. In this way, by continuously disposing the slits over the entire circumference of the outer peripheral wall, the water that has flowed out of the slits uniformly enters the convex surfaces of all the stationary blades, and all the statics in that stage It is possible to reliably prevent dust adhesion on the convex surface side of the blade.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine, it is desirable that the slit is disposed at a connecting portion between the bell mouth of the turbine and the turbine case. The bell mouth of the turbine and the turbine case are coupled to each other by a connecting portion provided on both sides, for example, generally a fraud portion. Therefore, by forming the slit and the water storage part using the connecting part, it is very easy to form the slit and the water storage part.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine, the stationary blade has a Zabuton portion extending radially outward from the blade root portion in the circumferential direction of the turbine, and the diameter of the Zabbton portion is ( The chord length is preferably 0.6 to 0.8). As described above, since most of the washing water flows in a layered manner along the outer peripheral wall portion of the turbine from the slit to the Zabton portion of the stationary blade, the diameter of the Zabton portion of the stationary blade is (the chord length × 0.6 ~ 0.8) and larger than the conventional, the amount of cooling of the stationary blade is increased by the washing water flowing in layers on the large Zabton part, and dust adhesion to the convex surface of the stationary blade is further prevented. .

  In the apparatus for preventing dust adhesion to the stationary blade of the furnace top pressure recovery turbine, the stationary blade is preferably a first stage stationary blade. As described above, dust is particularly likely to adhere to the rear edge of the convex surface side of the first stage stationary blade. Therefore, the dust adhesion preventing device for the stationary blade of the furnace top pressure recovery turbine is optimally implemented for the first stage stationary blade.

  The apparatus for preventing dust from adhering to the stationary blades of a furnace top pressure recovery turbine according to the present invention is used in a furnace top pressure recovery turbine power generation facility to generate power by a generator that is driven and connected by blast furnace gas supplied from a blast furnace. Preventing adhesion of dust to the stationary blades of a furnace top pressure recovery turbine having a furnace top pressure recovery turbine to be performed and a water supply device for supplying water for water washing to the stationary blades of the turbine through a water supply path In the apparatus, the turbine has a slit extending in the circumferential direction on the outer peripheral wall portion on the upstream side of the stationary blade, and the slit supplies water supplied from the water supply device to the downstream side of the turbine and the outer peripheral wall of the turbine. Because the dust flows out in a layered manner along the section, dust attached to the stationary blades of the furnace top pressure recovery turbine can be reliably removed with a small amount of water, and stable and efficient operation is possible even during long-term continuous operation. It can be continued, an excellent effect that.

It is a schematic diagram which shows a wet furnace top pressure collection | recovery turbine power generation equipment. It is a side view which shows the furnace top pressure recovery turbine of FIG. It is sectional drawing of the 1st stage stationary blade of the furnace top pressure recovery turbine of FIG. It is a longitudinal cross-sectional view which shows the dust adhesion prevention apparatus to the stationary blade of the furnace top pressure recovery turbine of this invention. It is an expanded sectional view which shows the slit of FIG. FIG. 6 is an enlarged cross-sectional view showing another slit different from FIG. 5. It is a figure which shows the flow of the water of the furnace top pressure recovery turbine of FIG. It is a figure which shows the flow of the water on the stationary blade of the furnace top pressure recovery turbine of FIG. It is a schematic diagram which shows the dust adhesion state of the conventional wet furnace top pressure recovery turbine.

  An embodiment for carrying out an apparatus for preventing dust adhesion to a stationary blade of a furnace top pressure recovery turbine according to the present invention will be described in detail with reference to FIGS. 1 to 8.

  As shown in FIG. 1, as an example, in a wet furnace top pressure recovery turbine power generation facility that uses a turbine in an exhaust gas passage of a blast furnace plant and uses it for power generation or the like, blast furnace gas exhausted from the blast furnace 1 is dust. Guided to the furnace top pressure recovery turbine 10 through the catcher 2, the wet dust collector 3, the inlet closing valve 4, the emergency shut-off valve 5, and the regulator valve 6 for adjusting the gas flow rate of the blast furnace gas to the turbine, The turbine 10 is driven to rotate.

  Electric power is generated by rotating the generator 7 connected to the turbine 10 by the furnace top pressure recovery turbine 10. The first stage stationary blade 11, the second stage stationary blade 12, and the third stage stationary blade 13 of the furnace top pressure recovery turbine 10 have a variable angle mechanism 15 for changing the angle with respect to the gas flow in order to continue stable and efficient operation. .

  A bypass passage for bypassing the blast furnace gas to the outside without passing through the furnace top pressure recovery turbine 10 is provided, and a bypass main valve 8 and a bypass control valve 9 for adjusting the flow rate of the blast furnace gas passing through the bypass passage are provided. The

  In the furnace top pressure recovery turbine power generation facility, when the furnace top pressure recovery turbine 10 is started and stopped, for example, the speed control valve opening control by the speed control valve 6 from the start start to the initial set speed is the initial set speed. The number of revolutions is controlled between the number and the set number of revolutions immediately before the start of the uniform speed. Further, a load is applied immediately after reaching the 100% rotation speed and entering the power grid, but load control is performed until the load increases and normal operation is performed. And turbine pre-pressure control is performed at the time of normal operation.

  On the other hand, when the turbine 10 is stopped, for example, load control is performed from the normal operation until the load is reduced and immediately before the disconnection, and the rotation speed control is performed from the set rotational speed immediately after the disconnection to the initial set rotational speed. . Further, the speed control valve opening degree control by the speed control valve 6 is performed until the engine speed is stopped from the initially set rotation speed.

  When the turbine 10 is started, the governor valve 6 is gradually opened while the pre-pressure of the turbine 10 is increased to the pressure during normal operation, and the gas is guided to the blade row. When the speed regulating valve 6 is almost fully opened, the stationary blades 11 to 13 provided with the angle variable mechanism 15 are gradually opened from the flow channel initial setting angle, and the normal operation is started. At this time, the bypass main valve 8 is fully closed while the bypass control valve 9 is gradually closed, so that the pre-pressure of the turbine 10 is always maintained at the pressure during normal operation.

  In this furnace top pressure recovery turbine power generation facility, the main control of the start and stop operation of the turbine 10 is the variable angle mechanism 15 of the stationary blades 11 to 13 or the speed regulating valve 6, and the bypass control valve 9 is Used to maintain the pre-pressure of the turbine 10 at the pressure during normal operation. In this way, power generation by the furnace top pressure recovery turbine and turbine pre-pressure control are performed.

  As shown in FIG. 2, for example, the furnace top pressure recovery turbine 10 includes a three-stage turbine, and includes a first stage stationary blade 11, a first stage stationary blade 16, a second stage stationary blade 12, a second stage stationary blade 17, and a third stage stationary blade 13. The third stage blade 18 is arranged in this order from the upstream side of the gas path. On the upstream side of the turbine case 20, a bell mouth 40 for smoothly introducing the suction gas into the first stage stationary blade 11 is disposed.

  As shown in FIG. 3, on the first stage stationary blade 11, a corrosion resistant coating 25 having high corrosion resistance is formed on the entire convex surface (negative pressure surface) 22 and concave surface (positive pressure surface) 23 of the base material 21. . Here, the corrosion-resistant film is a film that is specially modified to a silicone resin and has excellent corrosion resistance against acid and alkali, seawater resistance, and steam resistance in addition to the heat resistance inherent in the resin. This refers to a polysiloxane having a highly reactive functional group.

  For this reason, in the above-mentioned wet furnace top pressure recovery turbine power generation facility, the blast furnace gas discharged from the blast furnace 1 is washed with water by the wet dust removing device 3, and as a result, the blast furnace gas contains steam to a saturated state. The base material 21 is prevented from corroding even if dust adheres to the first stage stationary blade 11 due to saturated steam accompanied by dust that could not be recovered by the wet dust removing device 3. Further, the above-described corrosion-resistant film is also formed on the surface of the second stage stationary blade 12 and the third stage stationary blade 13.

  Further, a hydrophilic film 26 is further formed on the convex surface 22 of the first stage stationary blade 11 on the corrosion-resistant film 25. For the hydrophilic film 26, a film having particularly excellent wear resistance is used, and for example, the hydrophilic film 26 is formed by coating by a coating method or coating by a sintering method. In this way, by forming the hydrophilic film by coating by a coating method or coating by a sintering method, a hydrophilic film 26 having extremely uniform and stable wear resistance is formed on the convex surface 22 of the stationary blade 11. Can be formed.

  As described above, since the hydrophilic film 26 is formed on the surface of the convex surface 22 of the first stage stationary blade 11, even if dust adheres to the surface of the convex surface 22 of the first stage stationary blade 11, water washing or the like which will be described later. Due to the attached water droplets, a water film is formed between the hydrophilic film 25 and the dust, and the firmly attached dust is easily peeled off.

  As shown in FIG. 4, the outer peripheral wall portion 10 a of the turbine 10 upstream of the first stage stationary blade 11 has a slit 41 extending in the circumferential direction, and the slit 41 is a bell mouth (outer peripheral wall portion) 40 of the turbine 10. It is formed so that it may open to the gas path side of the connection part 10b between a turbine case (outer peripheral wall part) 20, and may continue over the perimeter of the circumferential direction.

  Between the bell mouth 40 and the turbine case 20, a concave portion is formed over the entire circumference so as to be concave on the bell mouth 40 side of the connecting portion 10 b. And the bell mouth 40 and the turbine case 20 are connected, and the large cavity continuously extended over the perimeter of the circumferential direction is formed in the upstream of the slit 41. As shown in FIG. This cavity becomes the water reservoir 42. The bell mouth 40 is provided with a water supply passage 43 for supplying water pressurized by an unillustrated water pump or the like from the external water supply device 30 to the water storage section 42.

  Since the above-described water storage section 42 forms a large cavity in this way and continuously extends along the slit 41 in the circumferential direction of the turbine 10, when the cleaning water is supplied from the water supply path 43. In addition, the supplied water flows in a layered manner along the outer peripheral wall portion 10a of the turbine 10 from the slit 41 in a continuous and uniform manner over the entire length thereof.

  At the same time, the total opening area of the slits 41 extending continuously in the circumferential direction in the outer peripheral wall portion 10a of the turbine 10 is the total minimum cross-sectional area of the water supply passage 43 for supplying water from the water supply device 30 to the water storage portion 42. It is much more widely formed. Therefore, the water supplied from the water supply device 30 flows out from the slit 41 into the turbine 10 after being reduced to a very low pressure. Due to the characteristics of the incompressible fluid, the pressure of water is weakened when it flows out of the water supply passage 43 into the water reservoir 42.

  Further, as shown in FIG. 5, the corner 41 on the downstream side of the outer peripheral wall portion 10a of the slit 41 is subjected to R machining 41a or chamfering 41b having an inclination angle of about 45 ° as shown in FIG. Has been.

  The water washing for the stationary blades 11 to 13 is normally performed after the furnace top pressure recovery turbine 10 reaches the rated operation state, that is, during normal operation.

  As described above, the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine has the slit 41 extending in the circumferential direction on the outer peripheral wall portion 10a on the upstream side of the first stage stationary blade 11. Moreover, the water storage part 42 which consists of the big cavity continuously extended over the perimeter of the circumferential direction is provided, and the total opening area of the slit 41 is formed much wider than the total minimum cross-sectional area of the water supply path 43. Yes. Therefore, the water supplied from the water supply device 30 is supplied to the turbine 10 through the slit 41 after being reduced to a very low pressure.

  Therefore, as shown in FIG. 7, the slit 41 causes the water supplied from the water supply device 30 of FIG. 4 to flow out to the downstream side of the turbine 10, but this outflowed water has dropped to an extremely low pressure. The water flowing out from the slit 41 to the downstream side of the turbine 10 flows in a layered manner along the turbine case 20 of the turbine 10. Then, it flows in a layered form as it is along the turbine case 20 and reaches the first stage stationary blade 11, and enters the convex side 22 of the first stage stationary blade 11 while remaining in a layered form.

  As shown in FIG. 8, the water that has entered the convex surface side 22 of the first stage stationary blade 11 has a bowl-shaped short columnar shape extending radially outward from the convex surface side 22 from the blade root portion 28 to both sides in the circumferential direction of the turbine 10. It flows in a layered manner to the Zabuton part (outer peripheral wall part) 27 and the blade root part 28 that follows it. On the other hand, it is known that a secondary flow of gas flowing from the outer blade root portion 28 to the radially inner side, that is, toward the center of the turbine 10 is generated on the convex surface side 22 of the first stage stationary blade 11.

  For this reason, the water that has flowed in layers to the outer blade root portion 28 on the convex surface 22 side of the first stage stationary blade 11 rides on the secondary flow of this gas flowing from the blade root portion 28 side toward the center of the turbine 10, On the blade surface on the convex surface 22 side, it flows in a layered manner from the blade root portion 28 side toward the center of the turbine 10, and then discharged from the center side on the convex surface 22 side to the downstream side of the turbine 10, and finally into the gas flow. Spread.

  In particular, the water flowing in a layered manner along the outer peripheral wall portion 10a of the turbine 10 up to the outer blade root portion 28 on the convex surface 22 side of the first stage stationary blade 11 is the first to which dust easily adheres due to the action of the gas flow. It flows more concentrated on the rear edge portion 22a of the step vane 11 on the convex surface 22 side. For this reason, dust adhesion that tends to occur on the rear edge portion 22a of the first stage stationary blade 11 on the convex surface 22 side is extremely effectively prevented, and dust that has already adhered is efficiently removed.

  In the apparatus for preventing dust from adhering to the stationary blade of the furnace top pressure recovery turbine described above, the total opening area of the slit 41 is wider than the total minimum cross-sectional area of the water supply passage 43 that supplies water from the water supply device 30 to the slit 41. Since it formed, the water which flowed out into the turbine 10 from the slit 41 comes to flow in a layered manner along the outer peripheral wall portion 10a of the turbine 10.

  In addition, a water storage section 42 for temporarily storing water supplied from the water supply apparatus 30 through the water supply path 43 is provided between the water supply path 43 on the upstream side of the slit 41, and the water pressure is reduced by the water storage section 42. Therefore, it is possible to flow in a layered manner from the slit 41 along the outer peripheral wall portion 10a of the turbine 10 more reliably.

  Further, since the corner 41 on the downstream side of the outer peripheral wall portion 10a of the slit 41 is subjected to the R processing 41a or the chamfering processing 41b, this also reliably follows the outer peripheral wall portion 10a of the turbine 10 from the slit 41. It can be flowed in layers. Further, since the slit 41 is disposed over the entire circumference of the outer peripheral wall portion 10a, it is possible to efficiently prevent dust from adhering to all the first stage stationary blades 11, and the slit 41 is formed on the outer peripheral wall portion 10a. Since it is continuous over the entire circumference, the water flowing out from the slit 41 can be uniformly fed into all the first stage stationary blades 11, and the dust adhesion on the convex surface 22 side of all the first stage stationary blades 11 can be surely achieved. Can do.

  Moreover, since the slit 41 is arrange | positioned in the connection part 10b between the bellmouth 40 of the turbine 10, and the turbine case 20, the above-mentioned slit 41 and the water storage part 42 are formed using the connection part 10b. This makes it very easy to form them. In addition, the formation of the water supply path 43 is easy.

  Then, the water diffused into the gas flow from the rear edge 22a of the first stage stationary blade 11 on the convex surface 22 side further cleans the second stage stationary blade 12 and the third stage stationary blade 13 on the downstream side. Of course, the water flowing in a layered manner along the turbine case 20 from the slit 41 also flows to the concave surface 23 side of the first stage stationary vane 11, and the concave surface 23 side is also washed with water.

  Further, since the cleaning water flows in a layered manner along the outer peripheral wall portion 10 a of the turbine 10 from the slit 41 to the Zabton portion 27 of the first stage stationary blade 11, by increasing the diameter of the Zabton portion 27, The amount of cooling of the first stage stationary blade 11 is increased by the washing water flowing in layers, and dust adhesion to the convex surface 22 of the first stage stationary blade 11 is further prevented. For this reason, the diameter of the Zabton portion 27 is formed to be (the chord length × 0.6 to 0.8). In particular, it is most desirable to have the maximum (blade chord length × 0.8) in the cascade theory.

  Thus, the dust adhesion prevention device for the stationary blade of the furnace top pressure recovery turbine of the present invention is pressurized and supplied from the water injection device like the conventional dust adhesion prevention device for the stationary blade of the furnace top pressure recovery turbine. Rather than injecting the generated water into the gas flow from the water injection nozzle, the water flows out in a layered manner along the outer peripheral wall portion 10a of the turbine 10 from the slit 41, and the gas on the convex surface 22 side of the first stage stationary blade 11 The first stage stationary blade 11 is washed with water using the secondary flow of

  Therefore, the dust adhesion preventing apparatus for the stationary blade of the furnace top pressure recovery turbine can surely remove the dust attached to the top pressure recovery turbine 10, particularly the first stage stationary blade 11, with a small amount of water. Stable and efficient operation can be continued even during continuous operation.

  As described above, the dust adhesion prevention device for the stationary blades of the furnace top pressure recovery turbine is based on a completely different technical idea from the conventional dust adhesion prevention device, and dust that can be expected to make dramatic progress in this field. It is an adhesion prevention device.

  A dust adhesion prevention device on the stationary blade of the furnace top pressure recovery turbine causes repeated stress on the first stage blade caused by dust adhesion on the stationary blade, thereby significantly increasing the fatigue limit of the blade. The problem of reducing, the problem of reducing the turbine efficiency without being able to form a proper gas flow, the problem of being unable to reduce the inflow of gas to the turbine to a predetermined flow rate when fully closed, and The problem that the first stage stationary blade bites into the dust deposits and causes damage to the blade portion can be solved at the same time.

  The slit is not necessarily limited to the upstream side of the first stage stationary blade, but may be provided upstream of the second stage or lower stationary blade. The present invention is not limited to the above-described embodiment, and various forms can be implemented.

  The apparatus for preventing dust adhesion to the stationary blade of the furnace top pressure recovery turbine of the present invention is not necessarily limited to the above-described wet furnace top pressure recovery turbine power generation turbine, but is applicable to other types of turbines. It can also be expected to be widely used.

DESCRIPTION OF SYMBOLS 1 Blast furnace 2 Dust catcher 3 Wet dust collector 4 Inlet closing valve 5 Critical shutoff valve 6 Control valve 7 Generator 8 Bypass main valve 9 Bypass control valve 10 Top pressure recovery turbine 10a Outer wall part 10b Connection part 11 1st Stage vane 12 Second stage vane 13 Third stage vane 15 Angle variable mechanism 16 First stage bucket 17 Second stage bucket 18 Third stage bucket 20 Turbine case 21 Base material 22 Convex surface 22a Trailing edge 23 Concave surface 25 Corrosion resistant coating 26 Hydrophilic film 27 Zabton part 28 Blade root part 30 Water supply device 40 Bell mouth 41 Slit 41a R processing 41b Chamfering process 42 Water storage part 43 Water supply path 101 First stage stationary blade 102 Convex surface 103 First stage moving blade

Claims (8)

  A furnace top pressure recovery turbine (10) that is used in a furnace top pressure recovery turbine power generation facility and that is driven to rotate by a blast furnace gas supplied from a blast furnace (1) and connected to a generator (7), and the turbine The apparatus for preventing dust from adhering to the stationary blade of the top pressure recovery turbine, comprising a water supply device (30) for supplying water for water washing to the stationary blade (11) of the turbine through the water supply passage (43) The turbine has a slit (41) extending in the circumferential direction on the outer peripheral wall portion (10a) on the upstream side of the stationary blade, and the slit feeds water supplied from the water supply device downstream of the turbine. An apparatus for preventing dust from adhering to a stationary blade of a furnace top pressure recovery turbine, wherein the dust flows out in a laminar manner along the outer peripheral wall portion of the turbine.   The total opening area of the slit (41) is wider than the total minimum cross-sectional area of the water supply passage (43) for supplying water from the water supply device (30) to the slit. The dust adhesion prevention apparatus to the stationary blade of the furnace top pressure recovery turbine of description.   The slit (41) includes a water storage section (42) for temporarily storing water supplied from the water supply device (30) through the water supply path (43) between the water supply path and the upstream side. The said water storage part is extended in the circumferential direction along the said slit, The dust adhesion prevention apparatus to the stationary blade of the furnace top pressure recovery turbine of Claim 1 or 2 characterized by the above-mentioned.   The corner portion of the outer peripheral wall portion (10a) on the downstream side of the slit (41) is subjected to R processing (41a) or chamfering processing (41b). The apparatus for preventing dust from adhering to the stationary blades of the top pressure recovery turbine described in 1.   The dust on the stationary blade of the top pressure recovery turbine according to any one of claims 1 to 4, wherein the slit (41) is disposed over the entire circumference of the outer peripheral wall (10a). Adhesion prevention device.   The said slit (41) is continuing over the perimeter of the said outer peripheral wall part (10a), The dust adhesion prevention apparatus to the stationary blade of a furnace top pressure recovery turbine of Claim 5 characterized by the above-mentioned.   The said slit (41) is arrange | positioned by the connection part (10b) between the bellmouth (40) of the said turbine (10), and a turbine case (20), The Claim 1 thru | or 6 characterized by the above-mentioned. The dust adhesion prevention apparatus to the stationary blade of the furnace top pressure collection | recovery turbine in any one.   The stationary blade (11) has a Zabuton portion (27) extending radially outward from the blade root portion (28) in the circumferential direction of the turbine (10), and the diameter of the Zabuton portion is (chord length × The apparatus for preventing dust from adhering to a stationary blade of a furnace top pressure recovery turbine according to any one of claims 1 to 7, wherein the apparatus is formed to have a thickness of 0.6 to 0.8).

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