JP2010028022A - Additive dissolving device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that an existing additive dissolving device requires a long processing time for completely dissolving a hard-to-dissolve additive powder since the hard-to-dissolve additive powder is put in transformer oil and dissolved while being dispersed by stirring. <P>SOLUTION: The transformer oil in which the additive powder is dispersed is pressurized to a high pressure and then atomized into a decompressed vacuum deaerating tank from an atomizing nozzle to be dissolved while the additive powder and transformer oil are given a shock, so the processing time up to complete dissolution becomes short. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an additive dissolving apparatus for dissolving a powdery additive such as hardly soluble BTA (benzotriazole) in a solvent such as insulating oil used in a transformer or the like.

  It is known from research in the 1970s that BTA has an effect of suppressing the flow electrification of a transformer. Recently, it has been found that BTA has an effect of suppressing copper sulfide generation in a transformer, which has been one of the causes of transformer accidents. Flow charging and copper sulfide production are known to increase over time, and adding BTA to transformer oil can avoid these risks and ensure the long-term reliability of aged transformers. It is valid. On the other hand, since the solubility of BTA powder in transformer oil is low, conventionally, BTA powder is completely dissolved in transformer oil over a long period of time in a separate stirring and dissolving tank that can be controlled in temperature. The water, air, etc. dissolved in the oil were degassed by sending to the vacuum deaerator (for example, Patent Document 1).

JP 2002-15919 A (paragraph 0004, FIG. 1)

  In the conventional additive dissolution apparatus, BTA powder, which is a poorly soluble additive, and transformer oil, which is a solvent, are placed in a stirring dissolution tank and mixed with a mixer having a propeller, etc., so the BTA powder is dissolved in the transformer oil. It has a problem that it takes a long time to do.

  This invention solves said subject and provides the additive melt | dissolution apparatus which can melt | dissolve a hardly soluble powdery additive (additive powder) rapidly.

  The additive dissolution apparatus according to the present invention includes an agitation / dissolution tank having an additive powder and a solvent inlet and stirring the additive powder in the solvent, a vacuum deaeration tank having an exhaust pump and depressurized, The spray nozzle provided in the said vacuum deaeration tank from the stirring dissolution tank was equipped with the oil feed pump which sends the said additive powder and the said solvent in a pressurized state.

  The additive dissolution apparatus of the present invention configured as described above sprays the solvent in which the additive powder is dispersed into a vacuum degassing tank under reduced pressure at a high pressure, so that the additive powder and the solvent are impacted. The additive powder can be dissolved in the solvent in a short time.

Embodiment 1 FIG.
Hereinafter, Embodiment 1 of the present invention will be described in detail with reference to the drawings. FIG. 1 is a configuration diagram showing a schematic configuration of an additive dissolution apparatus used in Embodiment 1 of the present invention. FIG. 2 is a saturation solubility curve for a BTA transformer oil (for example, type A-1 insulating oil defined in JIS C 2320).

  As shown in FIG. 1, the additive dissolving apparatus of the present invention includes a BTA container 101 containing BTA powder 1, an oil container 102 containing transformer oil 2, and a transformer that completely dissolves and degass the BTA after processing. A processing oil container 103 for containing oil 3, a stirring and dissolving tank 200 having an airtight bag 13 containing a stirring propeller 11 and a first heater 12, a spray nozzle 22 and a gas connected to the first oil feed pump 21 by piping. A rotary degassing pump 23 for exhausting, a vacuum deaeration tank 300 having a second oil feed pump 24, and a pipe and a valve for appropriately connecting each container and each tank.

  According to the saturation solubility curve for the BTA transformer oil in FIG. 2, the saturation solubility at 40 ° C. is about 400 mg / liter, and the saturation solubility at 60 ° C. is about 730 mg / liter. In order to completely dissolve BTA having low solubility, the BTA powder 1 having a fraction of the saturation solubility at a treatment temperature of 40 ° C. to 60 ° C. was put into the transformer oil 2. That is, a transformer oil in which BTA having a concentration of about 200 mg / liter is completely dissolved is obtained.

  Through the piping 111 of the BTA container 101 and the piping 112 of the oil container 102, 300 g of BTA powder 1 and 1500 liter of transformer oil 2 are injected into the airtight bag 13 provided in the stirring dissolution tank 200. With this injection, the airtight bag 13 itself swells as indicated by the broken line arrow in the figure. When the injection is completed, the stirring propeller 11 and the first heater 12 are energized, the BTA powder 1 is dispersed in the transformer oil 2, and the liquid temperature of the transformer oil 4 in which the BTA powder 1 is dispersed is 40. Heat to ℃. During this time, the gas generated or present in the airtight bag 13 is exhausted through an exhaust valve (not shown) provided on the upper portion of the airtight bag 13. As a result, the moisture and air once turned into gas are not dissolved in the transformer oil 2 again. When the liquid temperature of the transformer oil 4 reaches 40 ° C., the exhaust valve (not shown) is closed, and the airtight bag 13 is isolated from the external gas and sealed. The first heater 12 is energized until the liquid temperature of the transformer oil 4 in which the BTA powder 1 is dispersed reaches 60 ° C., and maintains the liquid temperature at 60 ° C. as it is.

  On the other hand, the gas in the vacuum deaeration tank 300 is exhausted through the pipe 132 by the operation of the rotary pump 23 while the liquid temperature of the transformer oil 4 in the stirring dissolution tank 200 reaches 40 ° C. And reach a vacuum of about 100 mP. When the liquid temperature of the transformer oil 4 reaches 40 ° C., the first oil feed pump 21 is operated. The transformer oil 4 in which the BTA powder 1 is dispersed is sucked into the oil feed pump 21 from the stirring dissolution tank 200 via the pipe 121 at a flow rate of about 100 L / min, pressurized to about 0.3 MP, and It is injected into the vacuum deaeration tank 300 from five spray nozzles 22 (hole diameter: 1 mm) attached to the tip. Note that the number of spray nozzles 22 is a design matter and need not be particularly five. At this time, since the transformer oil 4 in which the BTA powder 1 is dispersed is released from a high pressure into a vacuum, it is sprayed while the water and gas components dissolved in the oil are vaporized and expanded all at once. A reflecting plate 25 is provided at an opposing position of about 30 cm with respect to the spray hole of the spray nozzle 22, and the BTA powder 1 and the transformer oil 5 that are sprayed in the meantime collide with each other at high speed, Since the BTA powder 1 is also refined at once, stirring and diffusion dissolution are repeated at a high speed, so that the dissolution rate in the transformer oil is remarkably increased.

  The transformer oil 5 in which the sprayed BTA powder 1 is dissolved and dispersed is converted into a liquid again while releasing the dissolved water and gas by the action of the rotary pump 23. The oil 6 is accumulated at the bottom of the vacuum deaeration tank 300. At this time, the reduced BTA powder 1 remains in the BTA-dissolved transformer oil 6. A second heater 26 is provided at the bottom of the vacuum deaeration tank 300, and the BTA-dissolved transformer oil 6 accumulated at the bottom is heated, and the liquid temperature is 60 until the amount is accumulated to a predetermined amount. Reach ℃. In addition, you may provide the stirring apparatus 27 in the bottom of the vacuum deaeration tank 300. FIG.

  When the transformer oil 6 reaches a predetermined amount, the pipe 134 connected to the vacuum deaeration tank 300 and the pipe 122 connected to the stirring and dissolving tank 200 are connected using the three-way valve 400 and the second oil pump is operated. Thus, the transformer oil 6 in the vacuum deaeration tank 300 is inserted into the airtight bag 13 of the stirring dissolution tank 200. The inserted BTA-melting transformer oil 6 collides with the baffle plate 14 disposed at a position facing the discharge end of the pipe 122, and then comes into contact with the transformer oil 4 in which the BTA powder 1 is dispersed, and the stirring propeller 11 Are mixed together to form transformer oil 4 in which BTA powder 1 is newly dispersed. Then, the new transformer oil 4 is sprayed again from the stirring / dissolving tank 200 into the vacuum degassing tank 300, dissolved in the transformer oil while refining the BTA powder 1, and circulated to the stirring / dissolving tank 200.

  The liquid temperature of the transformer oil 4 in the stirring / dissolving tank 200 is heated to 60 ° C., and after a while, the BTA powder 1 in the stirring / dissolving tank 200 is completely dissolved in the transformer oil. The time required until the BTA powder 1 is completely dissolved in the transformer oil in the above process is shorter than when only the stirring dissolution tank 200 is used (when the vacuum degassing tank 300 is not used). It's time.

  After the BTA powder 1 in the stirring and dissolving tank 200 is completely dissolved in the transformer oil 2, a pipe 134 connected to the vacuum deaeration tank 300 and a pipe 113 connected to the processing oil container 103 using the three-way valve 400, And the transformer oil in the vacuum deaeration tank 300 is inserted into the processing oil container 103. Then, the transformer oil in the stirring / dissolving tank 200 gradually decreases, and the airtight bag 13 itself contracts. When the airtight bag 13 itself shrinks to a predetermined size, the energization of the agitation propeller 11 and the first heater 12 is stopped, the first oil pump 21 is stopped after a predetermined time, and then the second oil pump. 24, the rotary pump 23, the 1st heater 12, etc. are stopped, and the melt | dissolution process to the transformer oil 2 of BTA powder 1 is complete | finished in a shorter time than before. In the first embodiment of the present invention, the transformer oil is repeatedly degassed a plurality of times in the vacuum degassing tank 300, and is isolated from the external gas using the stirring and dissolving tank 200 having the airtight bag 13. Therefore, the special effect which can obtain the transformer oil 3 which is a moisture concentration lower than before is also acquired.

  In the first embodiment, BTA powder is used as an insoluble additive, and transformer oil is used as an insoluble solvent as an example. However, any combination of an insoluble additive and an insoluble solvent can be used. In the same manner as in the first embodiment, the dissolution treatment can be performed in a short time. Further, the airtight bag 13 used for preventing moisture and air from being dissolved again in the transformer oil 2 is an example, and the transformer oil in the stirring and dissolving tank 200 is isolated so as not to come into contact with external gas containing air and moisture. As long as it is a partition wall or a partition wall film for ensuring airtightness, any material may be used.

Embodiment 2. FIG.
Hereinafter, a second embodiment of the present invention will be described in detail with reference to the drawings. FIG. 3 is a block diagram showing a schematic configuration of an additive dissolving apparatus used in Embodiment 2 of the present invention. In addition, in each site | part in FIG. 3, the same code | symbol is provided to the part same as FIG. 1, or an equivalent part.

  As shown in FIG. 3, the additive dissolution apparatus according to the second embodiment of the present invention is connected to the pipe 121 connected to the stirring and dissolving tank 200 of the additive dissolution apparatus according to the first embodiment with a filter at the end of the pipe 121. -15 is attached, and other configurations are the same as those in the first embodiment.

  As a result of the research, it has been found that the BTA powder reduced to a certain extent (for example, a diameter of several tens of μm) in a state of about 80% or less of the saturation solubility can be completely dissolved in the vacuum deaeration tank 300. However, it was also found that the particle size at which the BTA powder dissolves depends on the structure of the vacuum deaeration tank 300, the running method thereof, and the BTA concentration dissolved in the transformer oil. Therefore, the filter 15 described in the second embodiment of the present invention has a filter diameter smaller than the particle diameter of the powder in which the BTA powder is completely dissolved in the vacuum degassing tank 300 under the processing conditions used. It is. Needless to say, the filter diameter can be easily confirmed each time the vacuum degassing tank to be used and the processing conditions such as the operation thereof are determined.

  In the first embodiment, the transformer oil is circulated between the stirring / dissolving tank 200 and the vacuum degassing tank 300 until the BTA powder 1 in the stirring / dissolving tank 200 disappears, and then the vacuum is removed after the BTA powder 1 disappears. It was necessary to put the transformer oil 3 in which the BTA powder 1 was completely dissolved into the processing oil container 103 through the deaeration tank 300. Therefore, in order to obtain the transformer oil 3 in which the BTA powder 1 is completely dissolved, it is necessary to carry out by batch processing. This is because when new BTA powder 1 is added to the transformer oil 3, it is necessary to wait for dissolution of the added BTA powder 1 each time.

  In the additive dissolution apparatus according to the second embodiment of the present invention, a filter is attached to the end of the pipe 121, so that the vacuum degassing is performed even before the BTA powder 1 in the stirring dissolution tank 200 is completely eliminated. The transformer oil 4 in which the BTA powder 1 sent to the tank 300 is dispersed dissolves the BTA powder 1 completely in the vacuum degassing tank 300, so that it is not necessarily between the stirring dissolution tank 200 and the vacuum degassing tank 300. There is no need to circulate the transformer oil, and the transformer oil 3 in which the BTA powder is completely dissolved can be put in the processing oil container 103. Therefore, the effect that the process for obtaining the transformer oil 3 containing no BTA powder can be continuously performed is newly obtained. Moreover, since the transformer oil 3 that does not contain BTA powder can be obtained even before the BTA powder 1 in the stirring dissolution tank 200 is completely removed, The effect of eliminating the need to set the value as low as a fraction of the saturation solubility of the transformer oil is obtained.

Embodiment 3 FIG.
Hereinafter, the third embodiment of the present invention will be described in detail with reference to the drawings. FIG. 4 is a block diagram showing a schematic configuration of another additive dissolving apparatus used in Embodiment 3 of the present invention. In addition, in each site | part in FIG. 4, the same code | symbol is provided to the same part thru | or an equivalent part as FIG. 1 or FIG.

  As shown in FIG. 4, the additive dissolution apparatus according to the third embodiment of the present invention has a BTA concentration meter attached to the stirring dissolution tank 200 of the additive dissolution apparatus according to the second embodiment. The piping for returning the transformer oil toward the inside 200 is eliminated, and the other configuration is the same as that of the first embodiment. The BTA densitometer may be any concentration measurement method such as concentration measurement by liquid chromatography or concentration measurement by infrared absorption spectroscopy, that is, measure the concentration of BTA in transformer oil. Anything is possible.

  It is known that even if an amount of BTA powder 1 that becomes a supersaturation condition is added to the stirring dissolution tank 200, the actual solubility of BTA is low, so that it does not reach about 80% of the saturation solubility without considerable time. It has been. Therefore, if the actual BTA concentration in the stirring dissolution tank 200 is about 80% or less of the saturation solubility, the BTA powder 1 sent to the vacuum degassing tank 300 is completely dissolved in the vacuum degassing tank 300. be able to.

  As shown in FIG. 4, the additive dissolving apparatus according to the third embodiment of the present invention includes a BTA concentration meter in the stirring and dissolving tank 200, so the BTA concentration in the transformer oil in the stirring and dissolving tank 200 is Can be confirmed. As a result, the BTA concentration in the transformer oil sent to the vacuum deaeration tank 300 can be controlled to about 80% or less of the saturation solubility, and attached to the end of the pipe 121 in such a state that the BTA concentration is controlled. The BTA powder 1 can be completely dissolved in the transformer oil in the vacuum deaeration tank 300 by performing the dissolution treatment while filtering with the filter-15. Therefore, the transformer oil 3 in which the BTA powder 1 is completely dissolved can be put into the processing oil container 103 from the vacuum deaeration tank 300. At that time, as shown in FIG. 4, there is no need for piping or the like for returning the transformer oil from the vacuum degassing tank 300 into the stirring and dissolving tank 200, and as in the additive dissolving apparatus of the third embodiment of FIG. In the same way, the BTA powder can be dissolved in a short time. Therefore, in the additive dissolution apparatus according to the third embodiment of the present invention, an amount of BTA powder 1 that becomes a supersaturation condition can be added to the stirring and dissolving tank 200, and a transformer that completely dissolves BTA in a short time. Oil 3 can be obtained. Moreover, the special effect that the transformer oil 3 which melt | dissolved BTA powder by high concentration from the conventional additive melt | dissolution apparatus can be obtained is acquired.

It is a schematic block diagram of the additive melt | dissolution apparatus used for Embodiment 1 of this invention. It is a saturation solubility curve which the transformer oil shows with respect to BTA. It is a schematic block diagram of the additive melt | dissolution apparatus used for Embodiment 2 of this invention. It is a schematic block diagram of the additive melt | dissolution apparatus used for Embodiment 3 of this invention.

Explanation of symbols

1 BTA powder (additive powder)
2 Transformer oil (solvent)
3 Transformer oil completely dissolved in BTA
4 Transformer oil in which BTA powder is dispersed 13 Airtight bag (partition, partition membrane)
15 Filter
21 First oil pump 22 Spray nozzle 23 Rotary pump (exhaust pump)
24 Second oil pump
200 Stirring dissolution tank 300 Vacuum degassing tank

Claims (6)

A stirring / dissolving tank having an additive powder and solvent inlet and stirring the additive powder in the solvent, a vacuum degassing tank having an exhaust pump and depressurized, and the vacuum degassing tank from the stirring / dissolving tank An additive dissolving apparatus comprising: an oil feed pump for feeding the additive powder and the solvent in a pressurized state to a spray nozzle provided therein. 2. The additive dissolving apparatus according to claim 1, further comprising a partition wall for separating the solvent and the external gas in the stirring and dissolving tank. 3. The additive dissolving apparatus according to claim 1 or 2, wherein a filter is provided on the inlet side of a pipe connecting the inside of the stirring and dissolving tank and the oil feed pump. 4. The additive dissolving apparatus according to claim 1, further comprising a concentration meter for measuring the concentration of the additive in the stirring dissolution tank. The additive dissolution apparatus according to any one of claims 1 to 4, further comprising a pipe for sending a liquid from a vacuum degassing tank to a stirring dissolution tank. 6. The additive dissolving apparatus according to claim 1, wherein the additive powder is a powder containing benzotriazole, and the solvent is a transformer oil.

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