JP2009160488A - Exhaust gas treating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas treating device to temporarily store, compressing and cooling an intermittently discharged exhaust gas containing a solvent to remove the solvent, which is capable of enhancing the stability to the explosion and fire, and of space-savingly preventing the generation of dew condensation of the gas discharge passage at a low cost. <P>SOLUTION: The exhaust gas treating device 1 is provided with a storing tank 3 to temporarily store the exhaust gas containing the solvent intermittently discharged, a compressor 4 to suck and compress the exhaust gas, which is arranged at the downstream of the storing tank 3, and a condenser 5 to cool the exhaust gas and to exhaust the treated gas that the solvent has been removed by condensation, which is arranged at the downstream of the compressor 4, wherein the storing tank 3 has a pipeline inside to become a gas passage 7 of the treated gas discharged from the condenser 5. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an exhaust gas treatment apparatus that cools and removes solvent-containing exhaust gas discharged intermittently.

  Various types of solvents are used in semiconductor and electronic equipment cleaning facilities, printing facilities, painting facilities, etc., depending on the application. Many of these solvents are highly volatile. Since the volatilized solvent has an adverse effect on the environment and the human body, its emission into the atmosphere is regulated. Therefore, an exhaust gas treatment device for the purpose of removing the solvent in the exhaust gas is connected to the cleaning equipment and the like. Moreover, since many flammable solvents are used, care is required.

  As a cleaning apparatus or the like, there is an apparatus that exhausts exhaust gas at a specific timing in one cycle by using a solvent in a part of one cycle process such as a cleaning / drying process. Such an apparatus discharges exhaust gas intermittently by repeating the process of one cycle.

  As an apparatus for treating exhaust gas, for example, in Patent Document 1, gas generated from a washing tank is sucked and compressed by a compressor and cooled to a predetermined temperature by a condenser (condenser and condensing recovery unit). A gas cooling recovery device for condensing and recovering the solvent therein is shown. In this apparatus, a pulsation absorption tank, a compressor for compressing the gas, and a condenser (condenser and condensing recovery unit) for cooling and recovering the gas by liquefying are arranged in this order from the washing tank generating the gas. The cooled gas after the treatment is discharged.

  When the exhaust gas is intermittently discharged from the cleaning tank, the flow rate of the exhaust gas is averaged by the pulsation absorption tank.

Japanese Utility Model Publication No. 6-29603

  In a conventional gas cooling and recovery apparatus disclosed in, for example, Patent Document 1, exhaust gas containing a large amount of solvent sucked from a cleaning tank is compressed by a compressor. Thereby, while exhaust gas becomes high temperature, the solvent concentration in exhaust gas also rises. For this reason, further consideration is necessary in view of high safety such that the exhaust gas may exceed the lower limit combustion range.

  Further, in the conventional gas cooling and recovery apparatus, the gas after the solvent is removed is discharged in a cold state. Thereby, there exists a problem that dew condensation occurs in the discharge channel of processed gas. For example, a heater may be arranged to heat the treated gas, but the cost is increased by the amount of the heater. Furthermore, a space for arranging the heater is required.

  The present invention has been made to solve such a problem, and in an exhaust gas treatment apparatus that temporarily stores, compresses, and cools solvent-containing exhaust gas discharged intermittently, an explosion occurs. Another object of the present invention is to provide an exhaust gas treatment apparatus that can improve the safety against fire and fire, and can prevent the occurrence of dew condensation in the gas discharge flow path at a low cost and in a space-saving manner.

  In order to achieve the above object, an exhaust gas treatment apparatus according to claim 1 of the claims includes a storage tank for temporarily storing solvent-containing exhaust gas discharged intermittently, and the storage tank. An exhaust gas treatment comprising: a compressor disposed downstream of the tank for sucking and compressing the exhaust gas; and a condenser disposed downstream of the compressor for cooling the exhaust gas and discharging the treated gas obtained by condensing and removing the solvent. In the apparatus, the storage tank is provided with a gas flow path for the processed gas discharged from the condenser.

  An exhaust gas treatment apparatus according to a second aspect is the one according to the first aspect, wherein the gas flow path is constituted by a U-shaped or a zigzag-type pipe line.

  An exhaust gas treatment apparatus according to a third aspect is the one according to the first aspect, wherein the gas flow path is formed of a coiled pipe line.

  According to a fourth aspect of the present invention, there is provided an exhaust gas treatment apparatus as described in any of the first to third aspects, wherein the gas flow path is provided with fins around it.

  According to the exhaust gas processing apparatus of claim 1, the storage tank disposed upstream of the compressor is provided with a gas flow path for the cooled processed gas discharged from the condenser. Since the exhaust gas is cooled by heat exchange between the treated gas and the exhaust gas inside the tank, the exhaust gas temperature sucked into the compressor is lowered. Therefore, even if it compresses with a compressor, since exhaust gas temperature can be made low, the safety | security with respect to an explosion or a fire can be improved. Moreover, since the exhaust gas temperature after compression becomes low, the exhaust gas temperature pumped to the condenser becomes low. Therefore, the cooling energy in the condenser can be saved. Further, since the treated gas is heated by exchanging heat with the exhaust gas inside the storage tank, it becomes close to normal temperature. For this reason, it is possible to prevent the occurrence of dew condensation on the surface of the discharge channel when the temperature of the gas discharge channel approaches normal temperature. Therefore, there is no need to arrange a heater and heat the treated gas, so the cost does not increase. Furthermore, since a space for arranging the heater is not required, the space can be saved.

  According to the exhaust gas treatment apparatus of the second aspect, the surface of the gas flow path can be increased by configuring the gas flow path with a U-shaped or zigzag folded pipe, so that the heat of the exhaust gas and the treated gas can be increased. The efficiency of exchange can be improved.

  According to the exhaust gas processing apparatus of the third aspect, since the surface area of the gas flow path can be increased by configuring the gas flow path with a coiled pipe, the efficiency of heat exchange between the exhaust gas and the treated gas can be increased. Can be improved.

  According to the exhaust gas treatment apparatus of the fourth aspect, since the area in contact with the exhaust gas is further increased by attaching fins to the periphery of the gas flow path, the efficiency of heat exchange between the exhaust gas and the treated gas is further improved. Can be made.

Preferred form for carrying out the invention

  Examples of the present invention will be described in detail below, but the scope of the present invention is not limited to these examples.

  FIG. 1 is a configuration diagram showing a use state of an embodiment of an exhaust gas treatment apparatus to which the present invention is applied.

  An exhaust gas treatment device 1 shown in FIG. 1 is connected to an exhaust gas generation device 30 to remove the solvent in the exhaust gas intermittently discharged from the exhaust gas generation device 30 to purify the exhaust gas and discharge it to the atmosphere.

  The exhaust gas generator 30 is, for example, a cleaning / drying device that cleans an electronic device with a solvent such as an organic solvent and vacuum-dryes it. Every time, the exhaust gas containing the volatile solvent is discharged intermittently.

  The exhaust gas generator 30 bubbles a cleaning / drying chamber 31 that performs cleaning / drying, a feed pump 32 that depressurizes the cleaning / drying chamber 31, and exhaust gas that is sucked and discharged from the cleaning / drying chamber 31 by the feed pump 32. And an aeration tank 33 for recovering a part of the solvent. From the aeration tank 33, exhaust gas at about normal temperature (for example, about 25 ° C.) is discharged.

  The exhaust gas treatment device 1 is configured by an introduction means 2, a storage tank 3, a vacuum pump 4, and a condenser 5 arranged in this order from the exhaust gas generation device 30 side.

  The introduction means 2 is provided with an intermittent introduction part and a continuous introduction part, and introduces the exhaust gas discharged from the exhaust gas generator 30 into the storage tank 3. The indirect introduction part introduces the exhaust gas in accordance with the exhaust gas emission, and the continuous introduction part continuously introduces the exhaust gas with a smaller limited flow rate than the intermittent introduction part. The intermittent introduction part connects the aeration tank 33 to the storage tank 3 to introduce exhaust gas 15, the manual valve 11 and the electromagnetic valve 12 attached to the pipe 15, and the control part 10 that controls the opening and closing of the electromagnetic valve 12. It consists of and. The manual valve 11 is a flow rate regulator that regulates the maximum flow rate. When the intermittent introduction part introduces the exhaust gas in accordance with the exhaust gas discharge, if the exhaust gas of the amount temporarily exceeding the processing capacity of the condenser 5 flows through the condenser 5, the manual valve 11 stores the exhaust gas. The maximum amount introduced into the tank 3 is regulated. Due to the restriction of the manual valve 11, the flow rate of the exhaust gas into the storage tank 3 is reduced. If the processing capacity of the condenser 5 is not exceeded, the manual valve 11 may not be provided.

  On the inlet side of the pipe 15 (aeration tank 33 side), a differential pressure sensor 18 for detecting a differential pressure from the atmospheric pressure is disposed. The differential pressure sensor 18 is connected to the control unit 10. The control unit 10 immediately opens the solenoid valve 12 when the detected value of the differential pressure sensor 18 becomes a predetermined value or less, that is, when the inlet pressure of the decompressed pipe 15 rises to become a predetermined pressure or more. . Further, the control unit 10 immediately closes the electromagnetic valve 12 when the detected value of the differential pressure sensor 18 becomes larger than a predetermined value, that is, when the inlet pressure of the pipe 15 decreases and becomes lower than the predetermined pressure. To do.

  In the continuous introduction portion, a manual valve 13 is attached to a bypass pipe 17 that bypasses the manual valve 11 and the electromagnetic valve 12. The manual valve 13 restricts the flow rate of the exhaust gas flowing through the manual valve 11 and the electromagnetic valve 12 attached to the pipe 15 as the continuous introduction portion to a small amount. The manual valve 13 may be an orifice that limits the flow rate. In this case, the limited flow rate limited by the manual valve 13 is smaller than the suction amount of the vacuum pump 4.

  The storage tank 3 is a pressure-resistant tank, temporarily stores the exhaust gas, and averages the flow fluctuation of the exhaust gas. A pipe 15 for introducing exhaust gas is connected to the input side of the storage tank 3. A vacuum pump 4 is connected to the output side of the storage tank 3 by piping.

  Inside the storage tank 3, a gas flow path for the processed gas discharged from the condenser 5 is arranged. This gas flow path is composed of a zigzag-type pipe line 7. The pipe line 7 is a metal (for example, copper) pipe line having excellent thermal conductivity, and is bent a plurality of times (five times in the drawing) as shown in the figure. A large number of metal (for example, aluminum) fins 8 having excellent thermal conductivity are provided around the pipe line 7. Both ends of the pipe line 7 are arranged so as to protrude to the outside by being sealed by the outer wall of the storage tank 3 so that the storage tank 3 can be connected to the pipe in a sealed state. Further, the pipe line 7 is arranged in the central portion of the storage tank 3 so that the exhaust gas flows therearound without the fins 8 being in contact with the inner wall of the storage tank 3.

  The size of the pipe line 7 including the fins 8 is configured so as not to affect the capacity of the storage tank 3.

  On the bottom side of the storage tank 3, a discharge valve 23 is attached for discharging the solvent liquefied inside and accumulated at the bottom to the outside. The discharge valve 23 automatically discharges the solvent when a certain amount of solvent is accumulated.

  The vacuum pump 4 is an example of a compressor according to the present invention, and sucks and compresses solvent-containing exhaust gas that is intermittently discharged from the exhaust gas generator 30 via the introduction means 2 and the storage tank 3 that are arranged upstream. . A condenser 5 is connected to the downstream of the vacuum pump 4 by piping.

  The condenser 5 cools the exhaust gas pumped from the vacuum pump 4 to condense the solvent. The condenser 5 is provided with an evaporator 20 of a refrigerator (refrigeration cycle) inside the container. A refrigerator main body 21 provided outside the condenser 5 is connected to the evaporator 20 by piping. The refrigerator main body 21 cools the evaporator 20 by circulating the refrigerant in the evaporator 20. The evaporator 20 is provided with fins (not shown) around its periphery to cool the exhaust gas flowing through it. On the bottom side of the condenser 5, a discharge valve 22 for discharging the cooled, condensed and liquefied solvent is disposed. A solvent recovery tank (not shown) is provided downstream of the discharge valve 22.

  One end of the conduit 7 of the storage tank 3 is connected to the downstream of the condenser 5 by a pipe 24. The other end of the pipe line 7 is connected to a discharge pipe 25 that discharges the processed gas to the outdoors.

  Next, the operation of the exhaust gas treatment apparatus 1 will be described with reference to FIG.

  The vacuum pump 4 operates continuously and sucks and compresses the exhaust gas via the introducing means 2 and the storage tank 3. During a period when the exhaust gas generator 30 does not discharge exhaust gas, the exhaust gas in the storage tank 3 is sucked by the vacuum pump 4 and the storage tank 3 is in a decompressed state. In this case, the solenoid valve 12 is closed, but the bypass pipe 17 is connected to the pipe 15 so that exhaust gas is continuously sucked. Since the bypass pipe 17 has a flow rate limited to a small amount by the manual valve 13, the inside of the storage tank 3 is in a decompressed state as compared with the inlet side of the pipe 15.

  When a large amount of exhaust gas is discharged from the exhaust gas generator 30 at a time, the inlet pressure of the pipe 15 increases, and the differential pressure from the atmospheric pressure detected by the differential pressure sensor 18 becomes a predetermined value or less. As a result, the control unit 10 controls the solenoid valve 12 to open. By opening the solenoid valve 12, the exhaust gas is introduced into the storage tank 3 not only from the continuous introduction part but also from the intermittent introduction part. In this case, since the storage tank 3 is depressurized, the exhaust gas is sucked at once and introduced into the storage tank 3. The exhaust gas introduced into the storage tank 3 is sequentially sucked into the vacuum pump 4 and the flow rate is averaged and sent to the condenser 5. Further, the remaining exhaust gas that could not be sucked into the storage tank 3 at the time of exhaust gas discharge is sucked into the vacuum pump 4 and sequentially sent to the condenser 5 through the storage tank 3. In this way, the exhaust gas is sequentially sent from the storage tank 3 to the condenser 5 so that the amount of exhaust gas to be processed is averaged. Since the condenser 5 only needs to be able to process a large amount of discharged exhaust gas during one cycle, a small device can be used. The storage tank 3 also has a capacity close to the total amount of exhaust gas that is intermittently discharged because the exhaust gas is sucked at once in accordance with the discharge and the remaining amount of exhaust gas is stored in accordance with the processing of the condenser 5. There is no need to provide a tank, and a small tank can be used. When the exhaust gas is almost processed, the inlet pressure of the pipe 15 starts to decrease. For this reason, since the differential pressure detected by the differential pressure sensor 18 exceeds a predetermined value, the control unit 10 controls the electromagnetic valve 12 to be closed. For this reason, the inside of the storage tank 3 is further reduced in pressure.

  The exhaust gas sequentially sent to the condenser 5 is cooled by the evaporator 20 to a low temperature (for example, −40 ° C.) where the solvent is condensed. For this reason, the solvent in the exhaust gas is liquefied and collected at the bottom of the condenser 5. When a certain amount of this liquefied solvent is accumulated, it is discharged from the discharge valve 22 and recovered in the solvent recovery tank. The exhaust gas is cleaned by liquefying and removing the solvent, and the treated gas cooled from the condenser 5 is discharged.

  The treated gas flows in the order of the pipe 24, the pipe line 7 of the storage tank 3, and the discharge pipe 25, and is discharged to the outdoors. When the treated gas flows through the pipe line 7 of the storage tank 3, the exhaust gas at a normal temperature stored in the storage tank 3 exchanges heat with the cooled treated gas in the pipe line 7. In this case, since the pipe line 7 is composed of a zigzag type pipe line, the surface area in contact with the exhaust gas is large. For this reason, heat exchange can be performed efficiently. Furthermore, since the pipe 7 is provided with fins 8, the area in contact with the exhaust gas is further increased. For this reason, heat exchange can be performed more efficiently.

  Through the heat exchange, the exhaust gas is cooled and the treated gas is heated. As an example, the exhaust gas and the treated gas each have a temperature of about 5 ° C.

  As the exhaust gas is cooled, a part of the solvent in the exhaust gas is liquefied in the storage tank 3 and collected at the bottom of the storage tank 3. When a certain amount of solvent is accumulated, it is discharged from the discharge valve 23. Since part of the solvent can also be removed in the storage tank 3, the load on the condenser 5 can be reduced.

  Since the exhaust gas is cooled by heat exchange, the exhaust gas temperature sucked into the vacuum pump 4 is lower than in the conventional configuration in which the pipe line 7 is not arranged in the storage tank 3. Therefore, even if it compresses with the vacuum pump 4, it does not become high temperature too much and it can make exhaust gas temperature low. As an example, the exhaust gas temperature is about 40 ° C. due to compression.

  Here, as an example of the solvent, the hydrocarbon-based cleaning agent HC-250 manufactured by Tosoh Corporation has n-decane as a main component and its flash point is 53 ° C. Even if the temperature of the exhaust gas rises due to compression, the temperature is lower than this flash point. Therefore, the occurrence of explosions and fires can be reliably prevented, and safety can be improved.

  Moreover, since the exhaust gas temperature after compression becomes low compared with the conventional structure which does not distribute the pipe line 7 in the storage tank 3, the exhaust gas temperature pumped to the condenser 5 becomes low. For this reason, the cooling energy in the condenser 5 can be saved.

  Further, since the treated gas is heated by exchanging heat with the exhaust gas inside the storage tank 3, it becomes close to normal temperature. For this reason, the temperature of the discharge pipe 25 which is a gas discharge flow path approaches normal temperature, and it is possible to prevent the occurrence of condensation on the surface of the discharge pipe 25. Therefore, for example, it is not necessary to arrange and heat a heater that heats the treated gas with external energy such as electric power, so that energy can be saved. In addition, there is no need to provide a heater, so there is no cost increase. Furthermore, since a space for arranging the heater is not required, the space can be saved.

  Next, another embodiment of a storage tank used in an exhaust gas treatment apparatus to which the present invention is applied will be described with reference to FIG.

  The storage tank 3a to the storage tank 3e shown in FIG. 2 are similar to the storage tank 3 in the container (outer wall) of the tank, and the form of the gas flow path of the processed gas disposed inside the storage tank 3 The form is different. Any storage tank 3a to storage tank 3e can be replaced with the storage tank 3 of the exhaust gas treatment apparatus 1 shown in FIG. It is possible to exchange heat with the treated gas flowing through

  In the storage tank 3a shown in FIG. 2 (a), the gas flow path arranged inside is constituted by a U-shaped pipe line 7a. A large number of fins 8 are provided around the pipe line 7a. Although the surface area of the pipe line 7a may be smaller than the pipe line 7 of the storage tank 3 depending on the outer diameter of the pipe, the surface area can be increased as compared with the case of using a straight line.

  In the storage tank 3b shown in FIG. 2 (b), the gas flow path disposed inside is constituted by a coiled pipe line 7b. The pipe line 7b is composed of a coiled pipe line wound in a loose winding. Since the surface area of the pipe line can be increased by forming the coil shape in this manner, the efficiency of heat exchange between the exhaust gas and the treated gas can be improved.

  In the storage tank 3c shown in FIG. 2 (c), unlike the storage tank 3 in FIG. For example, in the case where sufficient heat exchange can be performed without attaching the fins 8, the fins 8 are not attached to the pipe line 7, so that the configuration can be made inexpensively. Similarly, the U-shaped pipe line 7 a with the fins 8 shown in FIG. 2A can be configured without the fins 8.

  The storage tank 3d shown in FIG. 2 (d) is partially shown in an enlarged view, and shows an example in which a large number of fins 8 are attached to the coiled conduit 7b in FIG. 2 (b). Thus, the heat exchange efficiency can be improved by attaching a large number of fins 8 to the coiled pipe line 7b.

  In the storage tank 3e shown in FIG. 2 (e), a gas flow path is formed by connecting a plurality of stages (three stages in the figure) of the U-shaped pipes 7a shown in FIG. 2 (a). A large number of fins 8 are further attached to the pipe line 7a connected in a plurality of stages. Thus, by connecting in multiple stages, the surface area can be further increased, and the efficiency of heat exchange can be further improved. Similarly, the coiled conduit 7b of FIG. 2B and the zigzag folded conduit 7 of FIG. 2C can be connected in multiple stages, and a large number of fins 8 can be attached.

  In the gas processing apparatus 1 described above, an example in which the gas processing apparatus 1 is configured using a tank having a smaller capacity by arranging the introduction section 2 upstream of the storage tank 3 has been described. The gas processing apparatus 1 can also be configured by arranging a storage tank 3 of a tank having approximately the same capacity with respect to the amount of exhaust gas discharged, without arranging it. In this case, the gas processing apparatus 1 is configured by directly connecting the aeration tank 33 and the storage tank 3 by connecting the aeration tank 33 and the storage tank 3 with a large capacity pipe. Even in this case, it is possible to exchange heat between the exhaust gas introduced into the storage tank 3 and the treated gas flowing in the gas flow path.

It is a block diagram which shows the use condition of the waste gas processing apparatus to which this invention is applied. It is a block diagram which shows another embodiment of the storage tank used for the waste gas processing apparatus to which this invention is applied.

Explanation of symbols

  1 is an exhaust gas treatment device, 2 is an introduction means, 3, 3 a, 3 b, 3 c, 3 d, and 3 e are storage tanks, 4 is a vacuum pump, 5 is a condenser, 7, 7 a and 7 b are conduits, 8 is a fin, 10 Is a control unit, 11 and 13 are manual valves, 12 is a solenoid valve, 15 and 24 are pipes, 17 is a bypass pipe, 18 is a differential pressure sensor, 20 is an evaporator, 21 is a refrigerator main body, and 22 and 23 are discharge valves. , 25 is a discharge pipe, 30 is an exhaust gas generator, 31 is a washing and drying chamber, 32 is a feed pump, and 33 is an aeration tank.

Claims (4)

  A storage tank that temporarily stores solvent-containing exhaust gas discharged intermittently, a compressor that is disposed downstream of the storage tank and sucks and compresses the exhaust gas, and is disposed downstream of the compressor to cool the exhaust gas And an exhaust gas treatment apparatus comprising a condenser for discharging the treated gas from which the solvent has been removed by condensation, wherein the storage tank has a gas flow path for the treated gas discharged from the condenser inside. An exhaust gas treatment apparatus provided in   The exhaust gas processing apparatus according to claim 1, wherein the gas flow path is configured by a U-shaped or zigzag-type pipe line.   The exhaust gas treatment apparatus according to claim 1, wherein the gas flow path is configured by a coiled pipe line.   The exhaust gas treatment apparatus according to any one of claims 1 to 3, wherein fins are attached to the gas flow path.

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