JP2009160559A - Volatile organic matter recovery equipment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus for separating gas containing volatile organic matter into volatile organic matter and clean gas using a separation membrane, and cooling and recovering the separated volatile organic matter, while reducing running cost and eliminating the volatile organic matter discharged to the atmosphere. <P>SOLUTION: The apparatus is provided with a separation device 2 separating the gas G containing volatile organic matter V into the volatile organic matter V and clean gas C; an adsorption device 3 adsorbing the volatile organic matter V separated in the separation device 2; a liquefying device 4 recovering the volatile organic matter V adsorbed in the adsorption device 3 by liquefying; and a control part 18 controlling the separation device 2 and the liquefying device 4 according to the adsorbing status of the volatile organic matter V in the adsorption device 3. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a volatile organic substance recovery device that recovers a volatile organic substance by separating a volatile organic substance and a clean gas from a gas containing a volatile organic substance.

  Many proposals have been made as a device for collecting exhaust gas discharged from factories or the like and gasoline vapor discharged from a gas station or the like to prevent release to the atmosphere. Of these, considering the fact that the equipment can be used safely (no risk of ignition), that continuous processing is possible, that no large equipment is required, and that operation and maintenance are easy, etc. A volatile organic substance recovery device using a so-called separation membrane method is proposed in which the contained exhaust gas is separated into a solvent and a clean gas by a separation membrane, and the solvent trapped in the separation membrane is condensed and recovered by a cooling device. .

In gas separation by such a separation membrane method, the separated volatile organic matter is liquefied and recovered as needed, and therefore the cooling device has to be operated at all times. Although the cooling temperature of the cooling device differs depending on the solvent to be recovered, it requires a cooling capacity of about −20 ° C. to −40 ° C. Therefore, such a cooling device is always operated during the gas separation process. There was a problem that the running cost became high by keeping. Further, gas separation by the separation membrane method has a problem that when the concentration of volatile organic substances in the exhaust gas to be treated is changed, volatile organic substances that cannot be separated are released into the atmosphere as they are.
JP 2001-70737 A

  The present invention is an apparatus that separates volatile organic matter and clean gas using a separation membrane, and cools and collects the separated volatile organic matter, thereby reducing running costs and eliminating volatile organic matter released into the atmosphere. This is a problem to be solved.

  In order to solve the above problems, the present invention provides a separation means for separating a gas containing a volatile organic substance into a volatile organic substance and a clean gas, an adsorption means for adsorbing the volatile organic substance separated by the separation means, and this adsorption A liquefying means for liquefying and recovering the volatile organic substances adsorbed by the means, and a control means for controlling the separating means and the liquefying means in accordance with the state of adsorption of the volatile organic substances by the adsorption means.

  The adsorbing means comprises an adsorbent that adsorbs volatile organic substances, a weight measuring means for detecting the weight of the adsorbent, and a heating means for desorbing the volatile organic substances from the adsorbent, and the control means has an adsorbent weight. When it reaches a predetermined value, it is judged that the adsorbent adsorption amount is saturated, the heating means is operated to desorb the adsorbent, and the liquefying means is driven to cool and collect volatile organic substances. Yes.

  The separation means includes a gas separation module for separating volatile organic substances and an adjustment means for adjusting the inflow of gas to the gas separation module, and the control means is a unit time of the adsorbent weight detected by the weight measurement means. When the hit change value reaches a predetermined value, it is judged that the concentration of volatile organic substances in the gas is high, and the amount of gas flowing into the gas separation module is controlled by the adjusting means.

  Here, a plurality of adsorption means may be provided, and switching means for selectively switching introduction of volatile organic substances from the separation means may be provided. The adsorbent is preferably activated carbon, and the gas separation module is preferably a casing in which a silicone rubber hollow fiber membrane is housed.

  According to the present invention, compared to the conventional configuration in which the volatile organic substances separated by the separation means are immediately cooled and recovered, it is not necessary to always operate the cooling device, and the running cost can be reduced. In addition, by measuring the weight of the adsorbent and the weight change per unit time, it is possible to detect the saturation state of activated carbon and the concentration of volatile organic substances in the processing gas, and immediately regenerate the adsorbent and adjust the amount of processing gas. It is possible to reduce the risk of discharging volatile organic substances to the atmosphere. Furthermore, by providing a plurality of adsorption means and selectively switching the introduction of volatile organic substances from the separation means, the apparatus can be used continuously.

Embodiment 1 of the present invention will be described below with reference to the drawings.
FIG. 1 is a configuration diagram of Example 1, in which 1 is a volatile organic matter recovery device, and a separation device 2 that separates exhaust gas containing volatile organic matter into volatile organic matter and clean gas, and a separation device 2. The adsorbing device 3 adsorbs the volatile organic matter separated in step 1 and the liquefying device 4 that liquefies and recovers the volatile organic matter adsorbed by the adsorbing device 3.

  The separation device 2 includes a gas separation module 7 in which a hollow fiber membrane 6 is housed in an elongated hollow tubular casing 5, a pressure feed pump 8 that pumps an exhaust gas G into the gas separation module 7, and a clean discharged from the gas separation module 7. A flow rate adjusting valve 9 for adjusting the discharge amount of the gas C and a vacuum pump 10 for extracting the volatile organic substance V through the hollow fiber membrane 6 of the gas separation module 7 are provided.

  The gas separation module 7 has an inlet 5a for exhaust gas G containing volatile organic substances at one end in the longitudinal direction, an outlet 5b for clean gas C at the other end, and an outlet 5c for volatile organic substances V at the outer peripheral surface. Further, a pressure pump 8 is connected to the gas inlet 5a, a flow rate adjusting valve 9 is connected to the clean gas outlet 5b, and a vacuum pump 10 is connected to the volatile organic substance outlet 5c. The hollow fiber membrane 6 is made of a silicone rubber that is particularly excellent in permeability and separability with respect to volatile organic substances and that can be easily processed into a thin film, and is filled in layers along the longitudinal direction in the gas separation module 7.

  The adsorbing device 3 is configured by filling the housing 11 with an adsorbent 12 made of activated carbon, and a weight measuring device 13 for detecting that the adsorbed amount of the volatile organic substance V in the adsorbent 12 is saturated, A heating device 14 for heating and regenerating the agent 12 is provided. The housing 11 has an inlet 11 a communicating with the volatile organic matter outlet 5 c of the gas separation module 7 and an outlet 11 b connected to the liquefying device 4. The adsorbent 12 is appropriately selected depending on the intended use and conditions such as silica gel and zeolite in addition to activated carbon.

  The liquefying device 4 includes a cooling device 15 that cools the volatile organic matter V that is heated and regenerated by the heating device 14 of the adsorption device 3, and a recovery tank 16 that collects the cooled volatile organic matter V. The cooling device 15 includes an introduction port 15a that communicates with the volatile organic matter discharge port 10b of the adsorption device 3, and a discharge port 15b that is connected to the recovery tank 16, and includes a refrigerant pipe 17 through which a refrigerant flows. Has been.

  A control unit 18 is connected to the pumping pump 8, the flow rate adjusting body 9, the vacuum pump 10 of the separation device 2, the weight measuring device 13 of the adsorption device 3, the heating device 14, and the cooling device 15 of the liquefying device 4. The control of the control unit 18 is executed based on the weight of the adsorbent 12 detected by the weight measuring device 13. That is, the saturation state of the adsorbent 12 is recognized by the weight of the adsorbent 12, and the heating device 14 and the cooling device 15 are controlled, or the change in the weight of the adsorbent 12 per unit time causes the volatile organic matter V in the exhaust gas G to change. The content (concentration) or the separation processing limit of the separation device 2 is estimated, and the pumping pump 8 and the flow rate adjusting body 9 are controlled.

Next, the operation of the first embodiment configured as described above will be described. FIG. 2 is a timing chart showing the operation timing of each part.
The pressure pump 8 communicated with the exhaust gas source is driven, and the exhaust gas G containing the volatile organic substance V is introduced into the gas separation module 7 from the inlet 5a. The exhaust gas G introduced into the gas separation module 7 is evacuated by the vacuum pump 10 and separated into the volatile organic substance V and the clean gas C by the hollow fiber membrane 6 in the gas separation module 7, and the volatile organic substance V is discharged. While being extracted from the outlet 5c, the clean gas C from which the volatile organic substances V have been removed is discharged from the outlet 5b to the outside air. Here, the separation capability of the gas separation module 7 is affected by two parameters, an internal and external pressure difference with respect to the hollow fiber membrane 6 and a flow rate. For this reason, pressurization to the gas separation module 7 by the pressure feed pump 8 and the vacuum pump 10 and flow rate adjustment by the flow rate adjusting valve 9 are set according to the capability of the hollow fiber membrane 6, and the optimum pressure and flow rate are maintained. .

  Volatile organic substances V separated by the gas separation module 7 are introduced into the adsorption device 3 and adsorbed by the adsorbent 12. As shown in FIG. 2, the adsorbent 12 adsorbs the volatile organic substance V and increases its weight. When the adsorbent 12 reaches a predetermined weight Xt (about 30% increase of the adsorbent self-weight X), the adsorption amount is saturated. When the adsorbent 12 is saturated, the pumping pump 8 and the vacuum pump 10 are stopped, the suction of the exhaust gas G is interrupted, and the adsorbent 12 is regenerated. The regeneration of the adsorbent 12 is performed by heating the adsorbent 12 with the heating device 14 to desorb the volatile organic matter V, and then bringing the volatile organic matter V into contact with the pipe surface of the cooling device 15 and cooling it. The volatile organic substance V after desorption is recovered in the recovery tank 16 and reused or discarded.

  Moreover, while measuring the weight of the adsorbent 12, the weight change per unit time of the adsorbent 12 is also measured simultaneously. When the weight change of the adsorbent 12 exceeds the predetermined value ΔX, the concentration of volatile organic substances in the exhaust gas G introduced into the gas separation module 7 is high, or the flow rate of the exhaust gas G introduced into the gas separation module 7 is large. For this reason, there is a high possibility that the volatile organic matter V that cannot be separated by the gas separation module 7 will be released to the atmosphere from the discharge port 5b, so that the exhaust gas G introduced into the gas separation module 7 by adjusting the pressure pump 8 is adjusted. The amount of clean gas C discharged from the discharge port 5b is limited by limiting the amount or adjusting the opening of the flow rate adjusting valve 9.

FIG. 3 is a flowchart showing processing operations in the control unit 18.
In the control part 18, after driving the pressure feed pump 8 and the vacuum pump 10 (1), the weight measuring device 13 continuously measures the weight of the adsorbent 12 (2). When it is detected that the weight of the adsorbent 12 has reached the predetermined weight Xt (3), it is determined that the adsorbent 12 is saturated and the pumping pump 8 and the vacuum pump 10 are stopped (4). The apparatus 15 is driven (5) to regenerate the adsorbent 12. Thereafter, when the weight of the adsorbent 12 is recovered to near its own weight by the weight measuring device 13 (6), the process returns to the process (1) to restart the exhaust gas process.

  Further, when it is detected by the weight measurement of the process (2) that the weight change of the adsorbent 12 exceeds the predetermined value ΔX, (7) it is determined that the concentration of the volatile organic substance V is high or the flow rate of the exhaust gas G is large. Then, the amount of the clean gas C discharged from the discharge port 5b is limited by adjusting the opening degree of the pressure feed pump 8 and / or the flow rate adjusting valve 9 (8).

  Example 1 is configured as described above, and is characterized in that the separation by the hollow fiber membrane and the adsorption by the activated carbon are used in combination. With this configuration, compared to a configuration in which volatile organic substances separated by the hollow fiber membrane are immediately cooled and collected, it is not necessary to operate the cooling device at all times, and the running cost can be reduced. In addition, by measuring the weight of activated carbon and the change in weight per unit time, it is possible to detect the saturation state of activated carbon and the concentration of volatile organic substances in the processing gas, and immediately regenerate activated carbon and adjust the amount of processing gas. It becomes possible to reduce the risk of discharging volatile organic substances to the atmosphere.

  FIG. 4 is a configuration diagram of the second embodiment, and the same reference numerals are assigned to the same devices as those of the first embodiment. In Example 2, in order to realize continuous exhaust gas treatment, a plurality of adsorbers (two in this case) are provided side by side, and the adsorbers used at the regeneration timing of the adsorbent are switched.

  In FIG. 4, adsorption devices 3A and 3B are provided side by side, branch lines 19A and 19B are branched from the downstream of the vacuum pump 10, and on-off valves 20A and 20B are attached to communicate with the adsorption devices 3A and 3B, respectively. Further, the discharge ports of the adsorption devices 3A and 3B are connected to the liquefaction device 4, and the volatile organic substances V generated by the regeneration of the adsorbent in the adsorption devices 3A and 3B are cooled and collected. .

The operation in such a configuration will be described with reference to the timing chart of FIG.
First, the on-off valve 20A is opened, and the volatile organic substance V separated by the gas separation module 7 is introduced into the adsorption device 3A. When the weight of the adsorbent 12A in the adsorbing device 3A reaches the predetermined value Xt, it is determined that the adsorbing amount is saturated, the on-off valve 20A is closed, and the heating device 14A and the cooling device 15 are driven to regenerate and volatilize the adsorbent 12A. The organic organic substance V is collected.

  When the on-off valve 20A is closed, the on-off valve 20B is changed and the volatile organic substance V separated by the gas separation module 7 is introduced into the adsorption device 3B. Thereafter, when it is determined that the adsorbent 12B is saturated, the on-off valve 20B is closed, and the heating device 14B and the cooling device 15 are driven to regenerate the adsorbent 12B and recover the volatile organic matter V. In this way, exhaust gas treatment can be continuously performed by causing the adsorption devices 3A and 3B to function alternately.

1 is a configuration diagram of Example 1. FIG. FIG. 3 is a timing chart illustrating the operation timing of each unit in the first embodiment. FIG. 7 is a flowchart showing processing operations in the control unit 18. FIG. 6 is a configuration diagram of Example 2. FIG. 10 is a timing chart illustrating the operation timing of each unit in the second embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Volatile organic substance collection | recovery apparatus 2 Separation apparatus 3 Adsorption apparatus 4 Liquefaction apparatus 5 Casing 5a Inlet 5b Clean gas discharge port 5c Volatile organic substance discharge port 6 Hollow fiber membrane 7 Gas separation module 8 Pumping pump 9 Flow control valve 10 Vacuum pump 11 Housing 11a Inlet 11b Discharge 12 Adsorbent 13 Weight measuring device 14 Heating device 15 Cooling device 16 Recovery tank 17 Refrigerant pipe 18 Control unit 3A First adsorber 3B Second adsorber 19A Branch pipe 19B Branch pipe 20A Open / close Valve 20B On-off valve

Claims (6)

Separation means for separating a gas containing a volatile organic substance into volatile organic substance and clean gas, an adsorption means for adsorbing the volatile organic substance separated by the separation means, and a volatile organic substance adsorbed by the adsorption means are liquefied. And a control means for controlling the separating means and the liquefying means in accordance with the state of adsorption of the volatile organic substances by the adsorption means.
The adsorption means comprises an adsorbent that adsorbs volatile organic substances, a weight measuring means for detecting the weight of the adsorbent, and a heating means for desorbing the volatile organic substances from the adsorbent,
When the adsorbent weight detected by the weight measuring means reaches a predetermined value, the control means determines that the adsorbed amount of the adsorbent is saturated, operates the heating means to desorb the adsorbent, and 2. The volatile organic substance recovery device according to claim 1, wherein the volatile organic substance is cooled and recovered by driving the means.
The separation means includes a gas separation module for separating volatile organic substances, and an adjustment means for adjusting the inflow of gas to the gas separation module,
The control means determines that the concentration of volatile organic substances in the gas is high when the change value per unit time of the adsorbent weight detected by the weight measuring means reaches a predetermined value, and the adjusting means determines the gas separation module to be high. 3. The volatile organic substance recovery device according to claim 2, wherein the amount of gas flowing into the gas is controlled.
The volatile organic substance recovery apparatus according to any one of claims 1 to 3, further comprising a switching means that is provided with a plurality of the adsorption means and selectively switches the introduction of the volatile organic substances from the separation means.
5. The volatile organic substance recovery device according to claim 1, wherein the adsorbent is made of activated carbon.
The volatile organic substance recovery device according to any one of claims 1 to 4, wherein the gas separation module includes a casing with a silicone rubber hollow fiber membrane.

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