JP6081389B2 - Axial flow fan device and exhaust gas treatment system having the same - Google Patents

Description

  The present invention relates to an axial fan device and an exhaust gas treatment system including the same.

  Large axial fan devices are used as, for example, ventilators (for example, induction fans) in thermal power plants. These are suitable for increasing the capacity of boilers and consume less power at partial loads. It is used a lot. Lubricating oil is circulated and reused from the lubricating oil tank as a lubricant in the bearing portion of this axial fan device (Patent Document 1).

  As an axial fan device used in this boiler exhaust gas treatment system, for example, external normal temperature air is sucked and pushed into the boiler for combustion, and boiler exhaust gas is attracted and recirculated to the boiler side. The present invention is applied to an induction fan that keeps the pressure in the furnace slightly negative, an induction fan that sends desulfurization gas desulfurized by a desulfurizer to a chimney, a booster fan that boosts exhaust gas and ventilates the desulfurizer.

Japanese Patent Laid-Open No. 11-324997

  Here, in the case of an induction fan, it is necessary to protect the main bearing and the internal mechanism from dust and high temperature in the combustion exhaust gas. For this reason, there is a seal cooling mechanism that introduces external air into the axial fan device and performs sealing and cooling. It is attached.

By the way, the life and consumption factors of the axial fan device include corrosion, wear, fatigue, lubricant deterioration and the like. As for this corrosion, since the power plant is at the seaside, there are problems of corrosion due to salt, generation of bits due to corrosion of aluminum alloy, and fixation of sliding gaps due to chloride purification.
Further, when the axial fan device is stopped, the gas temperature is lowered, and moisture in the gas is condensed, so that highly corrosive drain is generated. There is a problem that this drain is mixed in the lubricating oil and its system and promotes deterioration.

The presence of a large amount of water in the lubricating oil rusts red rust of iron hydroxide at the metal part.
In addition, foreign matter is removed with a filter in the line where the lubricating oil is circulated and reused, but if red rust occurs, the filter breakthrough will be accelerated, so the function of the axial fan device must be kept sound. There is also a problem that it is not possible.

  Further, in the boiler operation method, in the DSS (daily start / stop) operation that is started and stopped every day, the axial fan device stops every time, so that there is a problem that moisture in the gas is often condensed. is there.

  Therefore, for example, in an exhaust gas treatment system of a boiler such as a power plant, the emergence of countermeasure technology with little deterioration of lubricating oil is desired for a large axial fan device.

  In view of the above problems, an object of the present invention is to provide an axial fan device in which deterioration of lubricating oil is reduced and an exhaust gas treatment system including the axial fan device.

A first invention of the present invention for solving the above-described problems is provided on a cylindrical outer cylinder, an inner cylinder arranged at a predetermined interval in the outer cylinder, and a base end side of the outer cylinder. and a motor, coupled to a drive shaft of said motor, a main shaft rotor blade is mounted in the interior of the inner cylinder, is arranged in the center of the inner cylinder, and blades mounted on the spindle, the movement A lubricating oil tank for supplying lubricating oil to the blade bearing; and a cooling gas introduction line for introducing a cooling gas containing CO ₂ having a CO ₂ concentration of 10% or more from the outside into the inner cylinder. Axial flow fan device.

  According to a second aspect of the present invention, there is provided an axial fan apparatus according to the first aspect, wherein a dehumidifier is interposed in the cooling gas introduction line.

  A third invention is the axial flow fan device according to the first or second invention, wherein a filter is interposed in the cooling gas introduction line.

A fourth invention is the axial fan apparatus according to any one of the first to third inventions, wherein the cooling gas is a desulfurization outlet gas containing CO ₂ from the desulfurization apparatus.

  A fifth invention is the axial fan apparatus according to any one of the first to fourth inventions, wherein the cooling gas has a temperature of 30 ° C. to 50 ° C.

  A sixth invention is a denitration device that removes nitrogen oxides (NOx) in exhaust gas from a boiler, and an air heater that is arranged on the downstream side of the denitration device and exchanges heat between the air introduced from the outside and the exhaust gas. A dust collector disposed on the downstream side of the air heater and removing dust in the exhaust gas; and a desulfurization device disposed on the downstream side of the dust collector and removing sulfur oxide (SOx) in the exhaust gas. And at least one of an induction fan for sending the exhaust gas to the chimney, a pushing fan for pushing air into the air heater, and a gas recirculation fan for recirculating the exhaust gas to the boiler side. The exhaust gas treatment system is characterized by applying the axial fan device of the invention.

  According to a seventh invention, in the sixth invention, a gas passage in which the axial fan device is disposed, a bypass passage that bypasses the gas passage provided with the axial fan device, and an inlet portion of the gas passage and the bypass passage An inlet damper and an outlet damper for closing the outlet portion, and during operation of the boiler, the bypass passage side is closed with the inlet damper and the outlet damper, and gas is introduced into the gas passage to The exhaust gas treatment system is characterized in that when the gas is ventilated and the boiler is stopped, the gas passage side is closed by the inlet damper and the outlet damper, and the gas is introduced into the bypass passage.

According to the present invention, since the cooling gas containing CO ₂ having a CO ₂ concentration of 10% by volume or more is used as cooling inside the inner cylinder of the axial fan apparatus, the thermal conductivity of CO _{2 in} the desulfurization outlet gas is higher than that of air. Since it is low, when high temperature gas flows in, heat is prevented from being transferred into the inner cylinder.

Further, when the desulfurization outlet gas containing CO ₂ is used as the cooling gas containing CO ₂ , since the oxygen (O ₂ ) ratio is lower than that of air, the oxidative deterioration of the lubricating oil is largely prevented.

When the desulfurization outlet gas containing CO ₂ is introduced into the axial fan device, the amount of moisture in the gas is reduced by the dehumidifier, thereby further preventing the hydrolysis action of the lubricating oil.

FIG. 1 is a schematic diagram of an axial fan apparatus according to the first embodiment. FIG. 2 is a schematic diagram of an exhaust gas treatment system including an axial fan device according to the second embodiment. FIG. 3 is a schematic view of a gas passage provided with the axial fan device according to the third embodiment during boiler operation. FIG. 4 is a schematic diagram of the gas passage provided with the axial fan device according to the third embodiment when the boiler is stopped.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

FIG. 1 is a schematic diagram of an axial fan apparatus according to the first embodiment.
As shown in FIG. 1, an axial fan device 11 according to the present embodiment has an inner cylinder 13 mounted at a predetermined interval in a cylindrical outer cylinder (gas 10 passage) 12. A motor 14 is mounted on the base end of the motor. A first main shaft 17 and a second main shaft 19 are fixed to the drive shaft 15 of the motor 14 via an intermediate shaft 16 and the like, enter the central portion of the inner cylinder 13, and the first main shaft 17 is a first stage bearing 21. The second main shaft 19 is rotatably supported by the second stage bearing 22. A first stage moving blade 23 is mounted on the first main shaft 17, and a second stage moving blade 24 is mounted on the second main shaft 19.

  When the drive shaft 15 of the motor 14 is driven and rotated, the first main shaft 17 and the second main shaft 19 are rotationally driven through the intermediate shaft 16 and the like, and the outer cylinder is driven by the first stage moving blade 23 and the second stage moving blade 24. The gas 10 is sucked from the 12 inlet side, compressed inside, and discharged from the discharge side (left side in the figure). In addition, you may make it provide a stationary blade as needed.

  Here, as the axial flow fan, for example, external ambient temperature air is sucked and pushed into the boiler for combustion, and the boiler exhaust gas is attracted and recirculated to the boiler side. An induction fan (GRF: gas recirculating fan) that keeps the furnace pressure inside the boiler slightly negative, an induction fan (IDF: induced draft fan) that sends desulfurized gas desulfurized by the desulfurizer to the chimney, and boosts the exhaust gas Examples thereof include a booster fan (BUF) that ventilates the desulfurizer, but the present invention is not limited to these.

  In the axial fan device 11 of the present embodiment, the lubricating oil tank 32 that circulates and stores the lubricating oil 31 from the bearings of the first stage moving blade 23, the second stage moving blade 24, the motor 14, and the like, and the lubricating oil The tank 32 includes a level meter 32a for monitoring the level of the lubricating oil 31, an oil supply port 32b, an air breather 32c, a suction strainer 32d, a drain line 32e, and a drain valve 32f.

The lubricating oil tank 32 sucks and feeds the lubricating oil 31 by the pump P to the second stage bearing 22 of the second stage moving blade 24 using the first lubricating oil supply line L ₁ . 1 to store lubricant return the lubricating oil return line L _2.

The lubricating oil tank 32 sucks and feeds the lubricating oil 31 with the pump P to the first stage bearing 21 of the first stage rotor blade 23 using the second lubricating oil supply line L _11, and the 2 lubricating oil return line L ₁₂ returns to store lubricant.

Further, the lubricating oil tank 32 uses the third lubricating oil supply line L ₂₁ to suck and feed the lubricating oil 31 to the step bearing 14 a and the oil pump 14 b of the motor 14, as well as third lubricating. an oil return line L ₂₂ returns to store lubricant.
Each first lubricating oil supply line L ₁ , second lubricating oil supply line L ₁₁ , and third lubricating oil supply line L ₂₁ is provided with a filter 41 to remove foreign matter such as rust and dust. Yes. Note that the second lubricating oil supply line L _11, the oil cooler 42 is interposed, and the lubricating oil 31 such that the feed in a cold state. In FIG. 1, reference numeral P denotes a lubricating oil pump, M denotes a motor for driving the lubricating oil pump P, 73 denotes a gas introduction fan, and 74 denotes a damper.

In the present embodiment, the desulfurization outlet gas 110 is used as a cooling gas containing CO ₂ having a CO ₂ concentration of 10% by volume or more, and is introduced into the inner cylinder by the gas supply line 111 to cool and cool the space in the inner cylinder 13. I try to seal it. Note that the atmosphere is excluded because the CO ₂ concentration in the atmosphere is as low as about 0.4% by volume.

In this embodiment, a dehumidifier 131 containing a dehumidifying agent is interposed in the gas supply line 111. Examples of the dehumidifying agent include aluminum oxide (Al ₂ O ₃ ).

As a result, when the desulfurization outlet gas 110 containing CO ₂ having a CO ₂ concentration of 10% by volume or more is introduced into the inner cylinder 13 as a cooling gas, moisture in the desulfurization outlet gas 110 is removed. Further, it is possible to prevent deterioration due to hydrolysis and decrease in emulsification when drain water generated when compressed in the inner cylinder 13 is mixed into the lubricating oil 31.

In this embodiment, the desulfurization outlet gas 110 discharged from the desulfurizer to the chimney is used as the cooling gas containing CO ₂ having a CO ₂ concentration of 10% by volume or more. However, the present invention is not limited to this. is not.
Further, as an example of a cooling gas containing CO ₂ having a CO ₂ concentration of 10% by volume or more other than the desulfurization outlet gas, for example, gas that has passed through a filter of diesel engine exhaust gas or CO ₂ after being used for storage of a boiler Inert gas or the like can be used.

According to the present embodiment, the inside of the inner cylinder 13 of the axial fan apparatus 11 is used by using a cooling gas containing CO ₂ having a CO ₂ concentration of 10% by volume or more instead of introducing the atmosphere as a cooling gas as in the prior art. Since the thermal conductivity of CO ₂ is lower than that of air, the heat of the gas 10 is prevented from being transferred into the inner cylinder when the high-temperature gas 10 is introduced.

Here, air has a thermal conductivity of 0.0280 W / mk (50 ° C.), whereas carbon dioxide (CO ₂ ) has a low thermal conductivity of 0.0183 W / mk (50 ° C.).

The properties of the desulfurization outlet gas are, for example, CO ₂ (15% by volume (hereinafter “%”)), N ₂ (75 to 80%), O ₂ (2 to 4%), and H ₂ O (6%). On the other hand, since the properties of air are CO ₂ (about 0.4%), O ₂ (21%), and N ₂ (78%), the desulfurization outlet gas 110 has an excessive amount of CO _2. , The proportion of oxygen is low.

Therefore, when the desulfurization outlet gas containing CO ₂ is used as the cooling gas containing CO ₂ , since the oxygen (O ₂ ) ratio is lower than that of air, the oxidative deterioration of the lubricating oil is largely prevented.

Further, the water content in the air, in the case of 50 ° C. is about 80 g / m ^3, drops to about 30 g / m ³ For 30 ° C.. The outlet temperature of the desulfurization apparatus is, for example, about 30 to 50 ° C.

Therefore, when the low-temperature desulfurization outlet gas 110 containing CO ₂ is introduced into the inner cylinder 13 of the axial fan device 11, the moisture content in the gas is further reduced by the dehumidifier 131, thereby hydrolyzing the lubricating oil. The action is further prevented.

Thus, the axial fan device 11 of the present embodiment is provided on the outer cylinder 12 having a cylindrical shape, the inner cylinder 13 arranged at a predetermined interval in the outer cylinder 12, and the base end side of the outer cylinder 12. Motor 14, a main shaft (first main shaft 17 and second main shaft 19) connected to the drive shaft 15 of the motor 14, and a rotor blade (first stage) disposed at the center of the inner cylinder 13 and mounted on the main shaft Since the moving blade 23 and the second stage moving blade 24) and the cooling gas introduction line 111 for introducing the cooling gas 110 containing CO ₂ from the outside into the inner cylinder 13 are provided, air is used as the cooling gas as in the conventional case. Compared with the case of using, deterioration due to moisture in the lubricating oil is greatly reduced.

FIG. 2 is a schematic diagram of an exhaust gas treatment system including an axial fan device according to the second embodiment. In addition, about the member which overlaps with the member of Example 1, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.
An exhaust gas treatment system 100 according to the present embodiment includes a denitration device 103 that removes nitrogen oxides (NOx) in exhaust gas 102 from a boiler 101, and air that is disposed on the downstream side of the denitration device 103 and is introduced from the outside. 109 and the exhaust gas 102 are disposed on the downstream side of the air heater 104, the dust collector 105 is disposed on the downstream side of the dust collector 105, and is disposed on the downstream side of the dust collector 105. A desulfurization device 106 that removes sulfur oxide (SOx), an induction fan (IDF) that sends the exhaust gas 102 to the chimney 107, a pushing fan (FDF) that pushes the air 109 into the air heater 104, and a boiler that removes the exhaust gas 102 The axial fan apparatus according to the first embodiment is applied to a gas recirculation fan (GRF) that is recirculated to the 101 side.
In FIG. 2, reference numeral 105 a is an ash treatment for treating the dust ash from the dust collector 105, 106 a is lime (CaCO ₃ ) used in the wet lime gypsum method, 106 b is oxidizing air, 106 c is gypsum, and 106 d is desulfurized. It is drainage.
Note that the desulfurization outlet gas 110 discharged from the chimney 107 is heated by the afterburner 108 and discharged after white smoke prevention measures are taken.

  In the present embodiment, the induction fan IDF, the pushing fan FDF, and the branching fans 111-1, 111-2, and 111-3 branching a part of the desulfurization outlet gas 110 from the desulfurization device 106 from the gas supply line 111, When introduced into the inner cylinder 13 of the axial fan device 11 of FIG. 1 applied to the gas recirculation fan GRF, heat is transferred into the inner cylinder when a high-temperature exhaust gas 102 such as FDF flows in. Will be prevented.

Further, since the desulfurization outlet gas containing CO ₂ is used, the oxygen (O ₂ ) ratio is lower than that of air, so that the oxidative deterioration of the lubricating oil is largely prevented.

When the desulfurization outlet gas containing CO ₂ is introduced into the axial fan apparatus, the moisture content in the gas is reduced by the dehumidifier 131, thereby further preventing the hydrolysis action of the lubricating oil.

  Further, in this embodiment, a filter 132 is provided on the upstream side of the dehumidifier 131, and the dust component in the desulfurization outlet gas 110 is removed so that the purified gas is introduced into the inner cylinder.

FIG. 3 is a schematic view of a gas passage provided with the axial fan device according to the third embodiment during boiler operation. FIG. 4 is a schematic diagram of the gas passage provided with the axial fan device according to the third embodiment when the boiler is stopped. In addition, about the member which overlaps with the member of Example 1 and 2, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.
In the present embodiment, the gas passage 120 in which the axial fan device 11 is disposed, the bypass passage 121 that bypasses the gas passage 120 provided with the axial fan device 11, and the inlet and outlet of the gas passage 120 and the bypass passage 121. An inlet damper 122 and an outlet damper 123 that close the section are provided. The inlet damper 122 and the outlet damper 123 can be opened and closed by a hinge 124.

  As shown in FIG. 3, during the operation of the boiler, the bypass passage 121 side is closed by the inlet damper 122 and the outlet damper 123, the gas is introduced into the gas passage 120, and the axial flow fan device 11 ventilates the gas. Like to do.

  On the other hand, while the boiler is stopped, as shown in FIG. 4, the gas passage 120 side is closed with the inlet damper 122 and the outlet damper 123, and the gas 10 is introduced into the bypass passage 121.

  As a result, as shown in FIG. 4, when the boiler is stopped, inflow to the axial fan device 11 due to a backflow of air or the like from the outside is prevented.

  As a result, even when the moisture in the exhaust gas is condensed due to the boiler stop, the gas passage 120 side is closed by the inlet damper 122 and the outlet damper 123, so that further condensation of moisture is prevented and condensation into the drain is performed. Inflow of water will be suppressed.

DESCRIPTION OF SYMBOLS 10 Gas 11 Axial-flow fan apparatus 13 Inner cylinder 31 Lubricating oil 110 Desulfurization exit gas 111 Gas supply line

Claims (7)

A cylindrical outer cylinder,
An inner cylinder arranged at a predetermined interval in the outer cylinder;
A motor provided on the base end side of the outer cylinder;
A main shaft connected to a drive shaft of the motor and mounted with a moving blade inside the inner cylinder ;
A moving blade disposed at the center of the inner cylinder and mounted on the main shaft;
A lubricating oil tank for supplying lubricating oil to the rotor blade bearing;
An axial flow fan device comprising a cooling gas introduction line for introducing a cooling gas containing CO ₂ having a CO ₂ concentration of 10% or more from the outside into the inner cylinder. In claim 1,
An axial flow fan device comprising a dehumidifier in the cooling gas introduction line. In claim 1 or 2,
An axial-flow fan device comprising a filter in the cooling gas introduction line. In any one of Claims 1 thru | or 3,
The axial flow fan device, wherein the cooling gas is a desulfurization outlet gas containing CO ₂ from the desulfurization device. In any one of Claims 1 thru | or 4,
The axial flow fan device, wherein the cooling gas has a temperature of 30 ° C to 50 ° C. A denitration device for removing nitrogen oxides (NOx) in the exhaust gas from the boiler;
An air heater that is arranged on the downstream side of the denitration device and exchanges heat between the air introduced from the outside and the exhaust gas;
A dust collector disposed on the downstream side of the air heater to remove the dust in the exhaust gas;
A desulfurization device that is disposed on the downstream side of the dust collector and removes sulfur oxide (SOx) in the exhaust gas,
An attraction fan for sending the exhaust gas to the chimney;
A pushing fan for pushing air into the air heater;
The exhaust gas treatment system according to any one of claims 1 to 5, wherein the axial fan device according to any one of claims 1 to 5 is applied to at least one of a gas recirculation fan for recirculating the exhaust gas to a boiler side. In claim 6,
A gas passage in which the axial fan device is disposed;
A bypass passage for bypassing the gas passage provided with the axial fan device;
An inlet damper and an outlet damper for closing an inlet portion and an outlet portion of the gas passage and the bypass passage;
During the operation of the boiler, the bypass passage side is closed with the inlet damper and the outlet damper, the gas is introduced into the gas passage, and the gas is ventilated with the axial fan device,
An exhaust gas treatment system in which the gas passage side is closed with an inlet damper and an outlet damper while the boiler is stopped, and gas is introduced into the bypass passage.

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