JP2009240857A - System of treating volatile organic compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve the efficiency of energy by reducing the amount of steam necessary for desorbing a volatile organic compound from an adsorbent in a system of treating volatile organic compounds. <P>SOLUTION: The system of treating volatile organic compounds includes a circulation means 4 and X8 for allow a part of volatile compound-containing steam, which is steam containing volatile compounds desorbed from an adsorbent 10 and discharged from a container 11, to merge with pure steam being the steam supplied to the container 11 with containing no volatile compounds to return it to the container 11. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The volatile organic compound contained in the gas to be treated is removed from the gas to be treated by adsorbing it with the adsorbent contained in the container, and the volatile organic compound adsorbed in the adsorbent is volatilized by supplying water vapor to the container. The present invention relates to a volatile organic compound treatment system that desorbs and recovers a volatile organic compound.

In a factory that handles various volatile organic compounds such as toluene and xylene, a processing system for processing a gas (processing target gas) containing the volatile organic compound is provided.
As such a treatment system, Patent Document 1 discloses that a gas to be treated is supplied to a container containing an adsorbent to adsorb a volatile organic compound, and the volatile organic compound adsorbed by the adsorbent is adsorbed with water vapor. Volatile organic compounds are desorbed from the agent and recovered by containing them in water vapor, and the water vapor contained in the volatile organic compounds is burned by a combustion device such as a gas turbine or boiler to decompose and detoxify the volatile organic compounds. Disclosed is a volatile organic compound processing system for processing.
Japanese Patent No. 3956996

  By the way, in order to desorb the volatile organic compound from the adsorbent, it is necessary to heat the inside of the container to a predetermined temperature. In order to efficiently and continuously desorb volatile organic compounds from the adsorbent, it is desirable to expose the adsorbent to water vapor at a predetermined flow rate or higher. For this reason, in the conventional volatile organic compound processing system, a large amount of water vapor is required to desorb the volatile organic compound from the adsorbent. For example, in order to efficiently desorb a volatile organic compound from an adsorbent, about five times as much water vapor as the volatile organic compound to be desorbed is required.

  The present invention has been made in view of the above-mentioned problems, and in a volatile organic compound processing system, energy efficiency is reduced by reducing the amount of water vapor necessary for desorbing a volatile organic compound from an adsorbent. The purpose is to improve.

  In order to achieve the above object, the present invention provides a volatile organic compound from the gas to be treated by supplying the gas to be treated containing the volatile organic compound into a container containing an adsorbent that adsorbs the volatile organic compound. The organic compound is removed, and when the supply of the gas to be treated is stopped, steam is supplied into the container to perform heating, thereby desorbing the volatile compound from the adsorbent and allowing it to be contained in the steam. A volatile organic compound treatment system to be recovered, wherein the volatile compound desorbed from the adsorbent and a part of the volatile compound-containing water vapor that is the water vapor discharged from the container are It is characterized by comprising a circulating means for joining the pure water vapor, which is the water vapor supplied to the vessel, without containing a volatile compound, and returning it to the vessel.

  According to the present invention having such characteristics, a part of the volatile compound-containing water vapor, which is the water vapor discharged from the container containing the adsorbent and containing the volatile compound desorbed from the adsorbent, is volatilized. It is merged with pure water vapor which is water vapor supplied to the vessel without containing any toxic compound, and is circulated again to the vessel.

  Moreover, in this invention, the said circulation means employ | adopts the structure of providing the ejector which uses the said pure water vapor as drive gas, and uses the said volatile compound containing water vapor as suction gas.

  Moreover, in this invention, the said circulation means employ | adopts the structure provided with the heating means which heats the said volatile compound containing water vapor | steam merged with the said pure water vapor | steam.

  Further, in the present invention, a configuration is adopted in which a purge means capable of purging with the pure water vapor the flow path through which the volatile compound-containing water vapor combined with the pure water vapor flows is adopted.

According to the present invention, volatile compounds desorbed from the adsorbent are contained, and part of the volatile compound-containing water vapor, which is water vapor discharged from the container containing the adsorbent, does not contain volatile compounds. It is merged with pure water vapor, which is water vapor supplied to the vessel, and is circulated again to the vessel.
In order to obtain a flow velocity environment for continuously desorbing volatile organic compounds from the adsorbent in the container, it is necessary to supply water vapor in the container at a predetermined flow rate or higher. A part of the set flow rate can be covered with the volatile organic compound-containing water vapor that is circulated and supplied. For this reason, it becomes possible to reduce the flow volume of the pure water vapor supplied to the container.
Therefore, according to the present invention, it is possible to improve energy efficiency by reducing the amount of water vapor required for desorbing the volatile organic compound from the adsorbent.

  Hereinafter, an embodiment of a volatile organic compound treatment system according to the present invention will be described with reference to the drawings. In the following drawings, the scale of each member is appropriately changed in order to make each member a recognizable size.

FIG. 1 is a schematic diagram showing an outline of a volatile organic compound processing system A in an embodiment of the present invention.
The volatile organic compound treatment system A is constructed in a factory that requires treatment of various volatile organic compounds such as toluene and xylene. As shown in FIG. 1, the adsorption device 1, the gas turbine 2, The first heat exchanger 3, the ejector 4, the second heat exchanger 5 (heating means), and a control device (not shown) are provided.

The adsorption device 1 includes a metal purification container 11 (container) having a shape in which an opening of a cylindrical member is closed with a dome-shaped member, and an adsorbent 10 provided in the middle stage inside the purification container 11. That is, the adsorbent 10 is accommodated in the purification container 11. For example, activated carbon can be used as the adsorbent 10.
The adsorption apparatus 1 removes VOC from a gas to be treated by adsorbing a VOC contained in a gas containing a volatile organic compound (hereinafter referred to as VOC), which is a gas to be treated, to an adsorbent 10 inside the purification container 11. .
The VOC adsorbed by the adsorbent 10 is desorbed from the adsorbent 10 and contained in the water vapor by supplying water vapor into the purification container 11 in a state where the supply of the processing target gas is stopped. That is, the adsorption apparatus 1 contains VOC in the water vapor supplied into the purification container 11 in a state where the supply of the processing target gas is stopped, and discharges it.

In the purification container 11 of the adsorption device 1, a pipe X 1 for supplying water vapor from the outside above the adsorbent 10, a pipe X 2 for discharging the treated gas from which VOC has been removed to the outside, and a lower side than the adsorbent 10 A pipe X3 for supplying the gas to be treated from the outside and a pipe X4 for discharging the water vapor contained in the VOC to the outside are connected.
Further, since it is necessary to cool the adsorbent 10, a pipe X <b> 5 that supplies air from the outside below the adsorbent 10 is connected to the pipe X <b> 3, so that air can be supplied into the purification container 11. .
The water vapor flowing through the pipe X4 is discharged from the purification container 11 and contains VOC. In the following description, the water vapor is referred to as VOC-containing water vapor (volatile organic compound-containing water vapor).

  An opening / closing valve Y1 is provided in the middle of the pipe X1, an opening / closing valve Y2 is provided in the middle of the pipe X2, an opening / closing valve Y3 is provided in the middle of the pipe X3, and an opening / closing valve Y4 is provided in the middle of the pipe X4. An on-off valve Y5 is installed in the middle of the pipe X5.

The gas turbine 2 includes a compressor 21, a combustor 22, and a turbine 23.
The compressor 21 is configured to pressurize air sucked from the outside into compressed air and supply the compressed air to the combustor 22.
The combustor 22 mixes and combusts the compressed air and fuel gas supplied from the compressor 21 and discharges them to the turbine 23. Further, the combustor 22 is supplied with water vapor contained in the VOC discharged from the adsorption device 1 via the pipe X4, and combusts the water vapor together with the fuel gas. Note that the amount of water vapor supplied to the combustor 22 via the pipe X4 is adjusted by a control valve Y20 provided immediately before the combustor 22.
The turbine 23 is rotationally driven by the kinetic energy and pressure energy of the combustion gas supplied from the combustor 22 to generate the driving force of the compressor 21 and the driving force of the load 6 outside the gas turbine 2. ing. The combustion gas (exhaust gas) discharged from the gas turbine 2 is discharged to the first heat exchanger 3 and the second heat exchanger 5.

  The first heat exchanger 3 is configured to generate water vapor using the heat held by the combustion gas supplied from the gas turbine 2. A part of the water vapor generated by the first heat exchanger 3 is used for a factory process via the pipe X6, and the remaining water vapor is supplied to the pipe X1 via the pipe X7 and supplied to the adsorption device 1. The In addition, the water vapor | steam supplied through the pipe X7 does not contain VOC, and the said water vapor | steam is called pure water vapor | steam in the following description.

The ejector 4 is provided at a connection portion between the pipe X7 and the pipe X1. The ejector 4 is connected to a pipe X8 connected to the pipe X4.
This ejector 4 uses pure water vapor supplied from the pipe X1 as a driving gas and uses VOC-containing water vapor supplied from the pipe X4 via the pipe X8 as a suction gas, and joins the VOC-containing water vapor to the pure water vapor. The pressure is increased and supplied to the adsorption device 1.
In other words, in the volatile organic compound processing system A of the present embodiment, a part of the VOC-containing water vapor discharged from the purification container 11 of the adsorption device 1 is joined to the pure water vapor by the ejector 4 and the pipe X8. 11 is returned. That is, in the volatile organic compound processing system A of the present embodiment, the circulation means of the present invention includes the ejector 4 and the pipe X4.

  The second heat exchanger 5 is connected to the pipe X8 and warms the VOC-containing water vapor flowing through the pipe X8 using the heat held by the combustion gas supplied from the gas turbine 2. Here, for example, the second heat exchanger 5 heats the VOC-containing water vapor flowing through the pipe X8 to the same temperature as the pure water vapor flowing through the pipe X7.

Further, in the volatile organic compound processing system A of the present embodiment, the pipe X8 that is a flow path of the VOC-containing water vapor that joins the pure water vapor can be purged with a part of the pure water vapor that flows through the pipe X7. A purge mechanism 100 (purge means) is installed. The purge mechanism 100 includes a pipe X10 that connects the pipe X7 and the pipe X8, and an on-off valve Y10 that is installed in the middle of the pipe X10. A control valve may be used instead of the on-off valve Y10.
Such a purge mechanism 100 purges the pipe X8 with pure water vapor by allowing the pure water vapor flowing through the pipe X7 to flow into the pipe X8 by opening the on-off valve Y10.

A control device (not shown) controls the overall operation of the system based on a control program stored in an internal memory, various control data, and the like. That is, the control device includes a control device that performs control calculation based on various control data and the like, and various input / output interface circuits that exchange data with each of the above-described components (such as the adsorption device 1 and the gas turbine 2). It is configured to control the above-described constituent devices in an integrated manner.
Such a control device includes, for example, an on-off valve Y1 provided on the pipe X1, an on-off valve Y2 provided on the pipe X2, an on-off valve Y3 provided on the pipe X3, an on-off valve Y4 provided on the pipe X4, and a pipe. The opening / closing operation of the opening / closing valve Y5 provided in the pipe X8 and the opening / closing operation of the opening / closing valve Y8 provided in the pipe X8 are controlled respectively, and the opening / closing of the control valve Y20 provided in the pipe X4, and the opening amount thereof are also controlled. It is the structure which can control each. The control device also controls the purge mechanism 100.

Next, an operation of processing VOC by the volatile organic compound processing system A configured as described above will be described with reference to FIGS.
2 to 4 are schematic diagrams showing the state of each process of the adsorption device 1, wherein FIG. 2 (a) is an adsorption process, FIG. 2 (b) is a pressurizing / heating process, and FIG. 3 (a). 3 shows a desorption process, FIG. 3B shows a switching stage from the desorption process to the cooling process, and FIG. 4 shows the cooling process. In the volatile organic compound processing system A of this embodiment, VOC is removed from the gas to be processed by repeatedly performing each of these steps.
2 to 4, the white display of each valve indicates the “open state”, and the black display of each valve indicates the “closed state”.

(Adsorption process)
As shown in FIG. 2A, the control device (not shown) closes the on-off valve Y1, the on-off valve Y4, and the on-off valve Y5, and opens the on-off valve Y2 and the on-off valve Y3. By opening the on-off valve Y2 and the on-off valve Y3, the gas to be treated containing VOC is sequentially supplied from the lower side to the adsorption device 1 via the pipe X3, and passes through the adsorbent 10 provided in the middle stage. Are sequentially discharged from the upper pipe X2.
In this adsorption process, the gas to be treated is purified because VOC is adsorbed on the activated carbon when passing through the adsorbent 10, and is discharged to the outside as a treated gas via the pipe X2.

(Pressurization and heating process)
Next, the control device closes the on-off valve Y2, the on-off valve Y3, the on-off valve Y4, and the on-off valve Y5 as shown in FIG. The valve Y1 is opened. When the on-off valve Y1 is opened, water vapor is sequentially supplied from the upper side to the purification container 11 of the adsorption device 1 via the pipe X1, and the inside of the purification container 11 is pressurized and heated, and the adsorbent 10 is exposed. The atmosphere is heated.

(Desorption process)
When the inside of the purification container 11 is sufficiently pressurized and heated, the control device closes the on-off valve Y2, the on-off valve Y3, and the on-off valve Y5 as shown in FIG. At the same time, the on-off valve Y1 and the on-off valve Y4 are opened. When the on-off valve Y1 and the on-off valve Y4 are in the open state, pure water vapor is sequentially supplied from the upper side to the purification container 11 of the adsorption device 1 via the pipe X1, and passes through the adsorbent 10 provided in the middle stage. VOC is desorbed, and VOC-containing water vapor, which is water vapor mixed with the desorbed VOC, is sequentially discharged through the lower pipe X4.

Here, in the volatile organic compound processing system A of the present embodiment, pure water vapor is supplied to the ejector 4 from the pipe X7 and escapes to the pipe X1 in the desorption process, so that the pure water vapor becomes the driving gas. Sucks VOC-containing water vapor flowing through the pipe X4 via the pipe X8.
Then, the VOC-containing water vapor sucked into the ejector 4 is merged with pure water vapor and supplied to the purification container 11 of the adsorption device 1.
That is, in the volatile organic compound processing system A of the present embodiment, a part of the VOC-containing water vapor is merged with the pure water vapor and circulated and supplied to the purification container 11 again.
For this reason, a part of the flow rate for obtaining the necessary water vapor flow rate in the purification vessel 11 can be covered by the VOC-containing water vapor, and the amount of pure water vapor supplied to the purification vessel 11 is reduced to the conventional volatile organic compound. It can be reduced with respect to processing system A.

The VOC-containing water vapor supplied to the ejector 4 via the pipe X8 is heated by the second heat exchanger 5.
For this reason, the inside of the purification container 11 can be prevented from being cooled by the VOC-containing water vapor supplied to the purification container 11 via the ejector 4, and the desorption efficiency can be prevented from being lowered.

Subsequently, when switching from the desorption process to the cooling process, which is the next process, the control device opens the on-off valve Y10 of the purge mechanism 100 as shown in FIG.
As a result, pure water vapor flows into the pipe X8 via the pipe X10, and the VOC-containing water vapor stored in the pipe X8 is pushed out and supplied to the gas turbine 2, so that the pipe X8 can be purged.

(Cooling process)
Next, in order to perform the cooling process, the control device closes the on-off valve Y1, the on-off valve Y3, and the on-off valve Y4 and opens the on-off valve Y2 and the on-off valve Y5 as shown in FIG. . When the on-off valve Y2 and the on-off valve Y5 are in the open state, air is sequentially supplied from the lower side to the adsorption device 1 via the pipe X5, passes through the adsorbent 10 provided in the middle stage, and passes through the upper pipe X2. It is discharged sequentially.
In this cooling step, the inside of the purification container 11 is decompressed and returned to normal pressure by opening the on-off valve Y2, and the atmosphere of the activated carbon is cooled by passing air through the adsorbent 10 to return to normal temperature. Become.

  Then, the control device shifts again to the adsorption step described above, and removes VOC from the gas to be processed by repeatedly performing the above steps in order.

According to the volatile organic compound processing system A of the present embodiment as described above, a part of the VOC-containing water vapor is merged with the pure water vapor and circulated and supplied to the purification container 11 again.
For this reason, a part of the flow rate for obtaining the necessary water vapor flow rate in the purification vessel 11 can be covered by the VOC-containing water vapor, and the amount of pure water vapor supplied to the purification vessel 11 is reduced to the conventional volatile organic compound. It can be reduced with respect to processing system A.
Therefore, according to the volatile organic compound processing system A of the present embodiment, the amount of water vapor required for desorbing VOC from the adsorbent 10 can be reduced, thereby improving the energy efficiency.

  As mentioned above, although preferred embodiment of this invention was described referring drawings, this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.

For example, in the above-described embodiment, the configuration in which the VOC desorbed by the gas turbine is burned is described.
However, the present invention is not limited to this, and it is also possible to adopt a configuration in which only the VOC is recovered by condensing the VOC-containing water vapor and separating the condensate into water and VOC.

  Moreover, it may replace with the ejector in the said embodiment, and you may provide the fan which ventilates and supplies a part of VOC containing water vapor | steam to the piping X1.

Moreover, the said embodiment demonstrated the structure provided with the 2nd heat exchanger 5 as a heating means of this invention.
However, the present invention is not limited to this, and a heater may be used as the heating means of the present invention.

  Moreover, in the said embodiment, although the volatile organic compound processing system A demonstrated the structure which has one adsorption | suction apparatus 1, this invention is not limited to the said structure, For example, several adsorption | suction apparatus 1 is included. The structure provided may be sufficient.

  In the above embodiment, the combustion apparatus is described as the gas turbine 2. However, the present invention is not limited to the above configuration, and may be various boilers such as an exhaust heat recovery boiler. good.

It is a schematic diagram which shows the outline | summary of the volatile organic compound processing system in one Embodiment of this invention. It is a schematic diagram for demonstrating operation | movement of the volatile organic compound processing system in one Embodiment of this invention. It is a schematic diagram for demonstrating operation | movement of the volatile organic compound processing system in one Embodiment of this invention. It is a schematic diagram for demonstrating operation | movement of the volatile organic compound processing system in one Embodiment of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Adsorption apparatus, 10 ... Adsorbent, 11 ... Purification container (container), 4 ... Ejector, A ... Volatile organic compound processing system, X8 ... Piping, X10 ... Piping, Y10 ... Open / close valve

Claims (4)

Supplying the gas to be treated from the gas to be treated by supplying the gas to be treated containing the volatile organic compound into a container containing an adsorbent that adsorbs the volatile organic compound, and supplying the gas to be treated A volatile organic compound treatment system for desorbing the volatile compound from the adsorbent and allowing it to be contained in the water vapor and recovering by supplying water vapor to the container while heating is performed and heating the container. ,
The volatile compound desorbed from the adsorbent is contained, and a part of the volatile compound-containing water vapor that is the water vapor discharged from the container is supplied to the container without containing the volatile compound. A volatile organic compound treatment system comprising a circulation means for joining the pure water vapor, which is the water vapor, and returning it to the container.   2. The volatile organic compound processing system according to claim 1, wherein the circulating means includes an ejector that uses the pure water vapor as a driving gas and uses the volatile compound-containing water vapor as a suction gas.   The volatile organic compound processing system according to claim 1, further comprising a heating unit configured to heat the volatile compound-containing water vapor that is merged with the pure water vapor. The volatile organic compound treatment according to any one of claims 1 to 3, further comprising a purge unit capable of purging the flow path through which the volatile compound-containing water vapor combined with the pure water vapor flows with the pure water vapor. system.

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