JP5485933B2 - Furnace top pressure recovery turbine - Google Patents

Description

  The present invention relates to a furnace top pressure recovery turbine, and more particularly to a furnace top pressure recovery turbine capable of preventing dust from adhering to a stationary blade of the 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.

  Thus, at present, most blast furnaces in domestic steelworks are equipped with wet or dry furnace top pressure recovery turbine power generation facilities. 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. 7, this dust causes a problem that a large amount adheres on the convex 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. In addition, there is a problem that an appropriate gas flow cannot be formed by the dust and the turbine efficiency is lowered. Furthermore, chlorine ions are dissolved in the mist in the blast furnace gas, and a corrosive atmosphere is created. Therefore, there is also a problem that the chlorine ion concentration is increased inside the deposited dust and the material is corroded.

  On the other hand, in order to perform the 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.

  Therefore, conventionally, as shown in FIG. 8, a non-hydrophilic (water-repellent) film 105 having excellent corrosion resistance is formed exclusively on the surface of the stationary blade, and the stationary blade does not corrode even if dust adheres to it. I have done so. However, when the non-hydrophilic film 105 is formed, even if the water droplet 106 adheres to the film 105, the water droplet 106 only gets on the surface of the film 105 because of its water repellency, and the dust 107 cannot be removed. .

  In this way, the formation of this non-hydrophilic film having excellent corrosion resistance cannot prevent dust from adhering at all. Water vapor has been sprayed or sprayed to remove attached dust and remove it (see, for example, Patent Document 1 and Non-Patent Document 1).

  On the other hand, the applicant of the present application condenses moisture 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 surface and thereby prevents dust from adhering to the first stage stationary blades has been disclosed (for example, see Patent Document 2).

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 spraying or spraying of water or steam from the inlet part of the turbine or the stationary blade upstream part during normal operation or the like to remove the adhering dust, Alternatively, the water contained in the blast furnace gas is condensed on the blade surface of the first stage stationary blade by circulating cooling water inside the first stage stationary blade to cool the first stage stationary blade, so that water droplets and / or A water film has been formed to prevent dust from adhering to the first stage stationary blade.

  However, the former top pressure recovery turbine, which removes adhering dust by spraying or spraying water or steam from the inlet part of the former turbine or the upstream part of the stationary blade, removes the flow of blast furnace gas through the turbine. Extremely fast, water droplets etc. do not reach the surface of the stationary blade, especially its convex surface (negative pressure surface), and water or steam can be sprayed or sprayed uniformly on all of the stationary blades arranged in the circumferential direction. There is a problem that you can not.

  In addition, even if water droplets reach the surface of the stationary blade, a non-hydrophilic film has been formed in the past. There is a problem that can not be.

  As described above, it is the actual situation that water injection alone is not sufficient to prevent the adhesion of dust to the first stage stationary blade, and the aforementioned first stage blade is repeatedly stressed to cause fatigue of the blade. The problem of significantly lowering the limit, the problem of reducing the turbine efficiency without forming an appropriate gas flow, and the problem of being unable to reduce the gas flow into the turbine to a predetermined flow rate when fully closed The problem of causing corrosion of the material due to accumulated chlorine ions in the dust, and the problem that the first stage stationary blade bites into the dust deposits and causes damage to the blade portion, etc. still remain unsolvable. ing.

  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.

  At the same time, in the power generation equipment using the dry furnace top pressure recovery turbine, dust adhesion to the turbine stationary blades is not as serious a problem as wet, but the dry furnace top pressure recovery turbine power generation equipment with good power recovery efficiency. Therefore, it is necessary to take measures against dust adhesion to the dry-type furnace top pressure recovery turbine.

  The present invention has been made to solve such a problem, and can prevent a large amount of dust from adhering to the stationary blade, and can continue stable and efficient operation even during long-term continuous operation. It is an object of the present invention to provide a furnace top pressure recovery turbine capable of achieving the above.

  In order to solve the above-mentioned problems, the means employed by the present invention includes a turbine and a generator connected to the turbine, and is rotated by a blast furnace gas supplied from a blast furnace and generates power by the generator. In the furnace top pressure recovery turbine, a hydrophilic film is formed on the surface of the stationary blade of the turbine.

  Thus, in the furnace top pressure recovery turbine of the present invention, since the hydrophilic film is formed on the surface of the stationary blade of the turbine, even when dust adheres to the blade surface, during normal operation where it adheres to the surface of the stationary blade A water film is formed between the dust and the blade surface by the action of the hydrophilic film due to the condensed water and water droplets at the time of jetting water, and the dust can be easily separated. That is, the stationary blade itself has a self-cleaning function. Also, especially in the case of condensed water during normal operation, this water film is uniformly generated over the entire outer surface of the blades arranged in the circumferential direction, so that all the stationary blades with hydrophilic coatings are uniformly dusted. Can be peeled off.

  The furnace top pressure recovery turbine is disposed in a wet furnace top pressure recovery turbine power generation facility, and the stationary blade is preferably a first stage stationary blade. In wet furnace top pressure recovery turbines, a large amount of dust adheres to the first stage stationary blades in particular, so the formation of a hydrophilic film on the surface of the first stage stationary blades ensures the most efficient dust adhesion. Can be prevented.

  The furnace top pressure recovery turbine is disposed in a dry furnace top pressure recovery turbine power generation facility, and the stationary blade is preferably a final stage stationary blade. In dry type top pressure recovery turbines, dust adheres to the stationary blades of the final stage in particular, so the formation of a hydrophilic film on the surface of the stationary blades of the final stage most effectively prevents the adhesion of dust. be able to.

  It is desirable to form a hydrophilic film on the convex surface (negative pressure surface) of the stationary blade. Since dust tends to adhere particularly to the convex side of the stationary blade, dust adhesion can be most effectively prevented by forming a hydrophilic film on the convex surface of the stationary blade.

  It is desirable that a corrosion-resistant film is formed under the hydrophilic film of the stationary blade. In this way, by forming a highly corrosion-resistant corrosion-resistant film under the hydrophilic film of the stationary blade, the corrosion resistance of the stationary blade can be further enhanced along with the self-cleaning function of the hydrophilic film. .

  It is desirable to form the hydrophilic film by coating by a painting 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 very uniform and stable hydrophilic film can be formed on the surface of the stationary blade.

  A furnace top pressure recovery turbine according to the present invention includes a turbine and a generator connected to the turbine, and is rotated by a blast furnace gas supplied from a blast furnace and is generated by the generator. Since a hydrophilic film is formed on the surface of the stationary blades, it is possible to prevent a large amount of dust from adhering to the stationary blades of the furnace top pressure recovery turbine, which enables stable and efficient operation even during long-term continuous operation. There is an excellent effect that it can be continued.

It is a schematic diagram which shows the wet furnace top pressure recovery turbine power generation equipment as an example. It is a side view which shows the furnace top pressure recovery turbine of FIG. It is sectional drawing which shows the 1st stage stationary blade of FIG. It is a graph which shows the relationship between the cooling temperature of saturated gas, and the amount of condensed water of saturated gas. It is a figure for demonstrating the function of a hydrophilic membrane | film | coat. FIG. 3 is a schematic diagram illustrating a state of water injection with respect to the first stage stationary blade of FIG. 2. It is a trial figure which shows the dust adhesion state of the conventional furnace top pressure recovery turbine. It is a figure for demonstrating the function of a non-hydrophilic film | membrane.

  An embodiment for implementing a furnace top pressure recovery turbine according to the present invention will be described in detail with reference to FIGS. 1 to 6.

  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. The turbine 10 is 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 governing valve 6 to rotate the turbine 10.

  The furnace top pressure recovery turbine 10 generates power by rotating the generator 7 connected to the 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 include an angle variable mechanism 15 for changing an angle with respect to the gas flow in order to continue stable and efficient operation. ing.

  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 the 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, 12, 13 provided with the angle variable mechanism 13 are gradually opened from the initial setting angle of the flow path, 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 one that mainly controls the start and stop operations of the turbine 10 is the variable angle mechanism 15 of the stationary blades 11, 12, 13, or the governing valve 6, and is a bypass control valve. 9 is used to maintain the pre-pressure of the turbine 10 at the pressure during normal operation. In this manner, 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.

  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 example, Santomo (registered trademark) is used for the corrosion-resistant film 25.

  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.

  On the convex surface (negative pressure surface) 22 of the first stage stationary blade 11, a hydrophilic film 26 is further formed 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. A film can be formed.

  Here, the hydrophilicity of the film is generally evaluated by the contact angle, and the hydrophilic film means a film having a contact angle of 50 degrees or less. This hydrophilic film 26 is extremely excellent in wettability as compared with the above-described corrosion-resistant film 25. For example, Crystacoat (registered trademark), WIN-KOTE (registered trademark), ZACROM (registered trademark), SG-KOTE (registered trademark) or the like is used. In addition, these are only examples of a hydrophilic membrane | film | coat and are not necessarily limited to these.

  Since the blast furnace gas containing saturated steam flows while adiabatically expanding downstream in the turbine 10, the gas temperature gradually decreases, during which a large amount of condensed water is generated, and water droplets and water films are formed on the blade outer surface. Is generated. As shown in FIG. 4, when the temperature of the saturated gas decreases by 10 ° C. in the turbine 10, condensed water having a weight of about 3% is generated.

  As shown in FIG. 5, since the hydrophilic film 26 is formed on the surface of the convex surface 22 of the first stage stationary blade 11 as described above, the adhering water droplets cause a gap between the hydrophilic film 25 and the dust 28. The water film 27 is formed, and the dust 28 that is firmly attached is easily peeled off. The dust 28 that is easily peeled off in this way is easily peeled off during operation. Since this water film is uniformly generated on the entire outer surface of all the blades arranged in the circumferential direction, the dust 28 and the like can be peeled off evenly on all the stationary blades on which the hydrophilic film is formed.

  That is, in the furnace top pressure recovery turbine of the present invention, the first stage stationary blade 11 itself has a self-cleaning function. As described above, conventionally, from the viewpoint of removing water droplets and preventing corrosion of the base material, a corrosion-resistant film having water repellency has been formed on the surface of the stationary blade. The film forms not only corrosion resistance but also hydrophilicity that provides a self-cleaning function and abrasion resistance.

  As shown in FIG. 6, water injection or water spraying is performed from a water injection device (not shown) to the first stage stationary blade 11 with a predetermined angle θ with respect to the mainstream gas. This is because the first stage stationary blade 11 has a certain angle with respect to the mainstream gas. The angle adjustment of the first stage stationary blade 11 is performed by the operation of the angle variable mechanism 15 described above. At this time, if the water jet or water spray directly collides with the concave surface 23 of the first stage stationary blade 11 and there is adhesion of dust or the like, the dust or the like attached by the force of this water injection is removed.

  On the other hand, the water jet or water spray does not directly collide with the convex surface 22 of the first stage stationary blade 11, but adheres to the surface as water droplets. Since the hydrophilic film 26 is formed on the surface of the convex surface 22 of the first stage stationary blade 11 as described above, the blade surface and the dust coated with the hydrophilic film by the attached water droplets, as in the normal operation, and dust. A water film is formed between them, and the dust adhering firmly becomes easy to peel off. The dust that has been easily peeled off in this manner is easily peeled off during the water jetting or water spraying or during the subsequent operation.

  As described above, the furnace top pressure recovery turbine of the present invention can prevent a large amount of dust from adhering to the stationary blades, and can continue stable and efficient operation even during long-term continuous operation. It is. Further, by preventing the adhesion of dust, it is possible to solve all the problems such as the corrosion of the base material.

  The hydrophilic film can be formed directly on the surface of the base material 21 without forming the corrosion-resistant film 25 on the base material 21 of the first stage stationary blade 11. In addition, by circulating cooling water inside the first stage stationary blade 11 and water-cooling the first stage stationary blade 11, moisture contained in the blast furnace gas is condensed on the blade surface of the first stage stationary blade 11 and on the blade surface. If the invention of a furnace top pressure recovery turbine that forms water droplets and / or a water film and thereby prevents dust from adhering to the first stage stationary blade 11 (see, for example, Patent Document 2) is performed at the same time, the dust adhesion preventing effect is further enhanced. It will be a thing.

  The above-described furnace top pressure recovery turbine power generation equipment is only an example, and there are various other types of wet furnace top pressure recovery turbine equipment. Of course, it can also be applied to the stationary blades of the furnace top pressure recovery turbine of the dry type furnace top pressure recovery turbine power generation facility. In this dry-type furnace top pressure recovery turbine, dust tends to adhere to the convex surface (negative pressure surface) of the final stage stationary blade, so a hydrophilic film is formed on the final stage stationary blade, particularly the convex surface (negative pressure surface). If formed, it is extremely effective in preventing dust adhesion. For power generation equipment using a dry type furnace top pressure recovery turbine, it is expected that the installation will increase in the future because of the high recovery efficiency of power, so it is useful to take measures against dust adhesion according to the present invention. .

  The furnace top pressure recovery turbine of the present invention is not necessarily limited to the above-described wet and dry furnace top pressure recovery turbine power generation facilities, and is extremely cost effective. It is expected to be widely used for other turbines.

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 11 First stage stationary blade 12 Second stage stationary blade 13 Third stage blade 15 Variable angle mechanism 16 First stage blade 17 Second stage blade 18 Third stage blade 21 Base material 22 Convex surface 23 Concave surface 25 Non-hydrophilic coating 26 Corrosion resistant coating 27 Water film 28 Dust 101 First stage stationary blade 102 Convex surface 103 First stage blade 105 Non-hydrophilic film 106 Water droplet 107 Dust θ Predetermined angle

Claims (6)

  A furnace top pressure recovery turbine that includes a turbine (10) and a generator (7) connected to the turbine and is rotationally driven by a blast furnace gas supplied from a blast furnace (1) and generates power by the generator. A furnace top pressure recovery turbine characterized in that a hydrophilic film (26) is formed on the surface of a stationary blade (11) of the furnace.   The furnace top pressure recovery turbine (10) is disposed in a wet furnace top pressure recovery turbine power generation facility, and the stationary blade is a first stage stationary blade (11). The furnace top pressure recovery turbine according to claim 1.   The furnace according to claim 1, wherein the furnace top pressure recovery turbine is disposed in a dry furnace top pressure recovery turbine power generation facility, and the stationary blade is a final stage stationary blade. Top pressure recovery turbine.   The furnace top pressure recovery turbine according to any one of claims 1 to 3, wherein the hydrophilic coating (26) is formed on the convex surface (22) of the stationary blade (11).   The top pressure recovery turbine according to any one of claims 1 to 4, wherein a corrosion resistant coating (25) is formed under the hydrophilic coating (26) of the stationary blade (11). .   The furnace top pressure recovery turbine according to any one of claims 1 to 5, wherein the hydrophilic film (26) is formed by coating by a painting method or coating by a sintering method.

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