JP5165838B2 - Gas treatment system - Google Patents

Description

  The present invention relates to a gas processing system such as harmful gases and odorous gases emitted from factories and the like, which should suppress atmospheric release for environmental measures.

  As a measure to prevent harmful chemical substances emitted from various factories from being released into the atmosphere, regulations on local government regulations have been set, and the types of harmful gases and the standard values for their concentrations are set. Therefore, for example, a method for treating various harmful substances as disclosed in Patent Document 1 has been proposed.

  Conventionally, as a relatively easy method of treating harmful substances, for example, a method of adsorbing on an adsorbent such as activated carbon, a method of cleaning by passing through an air washer, a method of direct combustion, a method of treating using a photocatalyst, a chemical There is a single treatment method such as a neutralization method. Among them, the simplest method is a method of removing harmful gas with an adsorbent, and is used when processing a very small amount of gas. In addition, when the harmful component has a high concentration, a method of directly burning the gas is used.

  However, the concentration of harmful gas that actually needs to be processed is often an intermediate concentration that is not suitable for any of these methods. In such a case, a method is generally adopted in which a harmful gas is once adsorbed by an adsorbent, and the adsorbed gas is desorbed and concentrated before being treated.

  FIG. 6 is a schematic diagram showing an example of such a conventional processing system. In the figure, a thick solid line indicates a gas flow path during an adsorption process in which an adsorbent adsorbs a gas component (removed component) to be removed contained in a gas to be treated (gas to be treated) such as a harmful gas. These show the gas flow path at the time of the desorption process which detach | leaves the adsorbed removal component from adsorption agent. Further, the black arrow indicates the flow of gas containing the removed component, and the white arrow indicates the flow of gas not containing or removed the removed component.

  For example, when the gas to be treated is exhausted during the day, the removal component is adsorbed by an adsorbent such as activated carbon provided in the adsorption unit 2. The degassed air that has been removed and cleaned by adsorption is discharged to the outside. The removal component adsorbed by the adsorbent is desorbed by sending heated air to the adsorption unit 2 while the discharge of the gas to be treated is stopped, such as at night. By sufficiently desorbing, a concentrated gas in which the removed components contained are concentrated compared to the gas to be treated before adsorption is obtained. This concentrated gas is sent to the processing device 3 and directly removed to process the removed component. The degassed air that has been removed and cleaned by combustion is discharged to the outside.

  According to this method, the removal component contained in harmful gas etc. can be removed with a simple apparatus. However, since the inside of the processing apparatus 3 has a combustion temperature of about 800 ° C. to 1000 ° C., extremely large combustion energy is required, and the material of the processing apparatus 3 must have high heat resistance.

  FIG. 7 shows an example of a different processing system in the past, and reduces the energy required for the processing apparatus 3. The meanings of the thick solid line, broken line, black arrow, and white arrow are the same as those in FIG.

  Similar to FIG. 6 described above, the removal component of the gas to be processed is adsorbed to the adsorption unit 2. While the process for adsorbing the gas to be treated is stopped, heated air is sent to the adsorption unit 2 to desorb the adsorbent. By sufficiently desorbing, a concentrated gas enriched with the removed components can be obtained. The concentrated gas is sent to the processing device 3 through a heat recovery device (heat exchanger) 4. The processing device 3 is composed of an oxidation catalyst, and catalytically burns the concentrated gas. The heat of reaction by the catalyst is recovered by the heat recovery device 4, and the concentrated gas sent to the processing device 3 is preheated by the heat to increase the reaction efficiency of the catalyst.

  In this method, since the concentrated gas is combusted using a catalyst, the combustion temperature is lower than in the case of direct combustion. When combustion is performed using an oxidation catalyst, the combustion temperature is about 200 ° C. to 300 ° C., so that the heat resistance of the processing device 3 can be greatly reduced.

  Further, the catalytic reaction can be promoted by exchanging heat between the degassed air whose temperature has risen through the oxidation catalyst and the low temperature concentrated gas before catalytic combustion by the heat recovery device 4 and preheating the concentrated gas before combustion. . Such an oxidation catalyst has a purification rate that varies depending on the inlet temperature. In order to obtain a purification rate of 95% or more, the oxidation catalyst must be at or above a predetermined inlet temperature according to the type and concentration of the removed component.

  However, at the time of desorption, the concentration of the concentrated gas varies depending on the temperature and amount of the desorption heated air, the amount of the removed component adsorbed, and the elapsed time.

  When the concentration of the concentrated gas and the inlet temperature are appropriate, the removal component is removed at a high purification rate during catalytic combustion, and a predetermined reaction heat is obtained. For example, when a gas with a concentration of 1000 ppm is burned by an oxidation reaction, the temperature rise value (difference between the inlet temperature and the outlet temperature) is determined depending on the type of gas. For example, it is 68 ° C. for isopropyl alcohol and 133 ° C. for toluene. If the temperature rise value is constant and the outlet temperature is constant, a constant amount of heat is always recovered by the heat recovery device 4, so that the concentrated gas fed to the processing device 3 is then heated to a constant temperature. It can be done easily. Therefore, the configuration of the control device can be simplified, and a heating means for heating the concentrated gas is not required, or the capacity can be reduced.

  However, when desorbing the adsorbed removal components, heated air is gradually sent into the adsorption unit 2, so that a concentrated gas having a low concentration and a low temperature enters the processing device 3 through the heat recovery device 4 in the initial stage. . In a state of low concentration and low temperature, a sufficient catalytic effect cannot be obtained, so that the purification rate is lowered. Further, the temperature rise due to catalytic combustion is reduced, and the amount of heat recovered by the heat recovery device 4 is also small. Therefore, the concentrated gas for heat exchange cannot be sufficiently heated, and a sufficient catalytic reaction promoting action cannot be obtained.

  On the other hand, if the concentration of the concentrated gas is too high, the temperature rise due to the reaction heat of the catalyst becomes excessive, and the heat resistance temperature of each member constituting the processing device 3 and the heat recovery device 4 must be increased.

  As another conventional gas concentrating device, there is a rotary adsorption device. In the rotary type adsorption device, an adsorbent is provided in a disk-shaped rotor, and the rotor is rotated to pass through the processing zone and the regeneration zone, and the gas to be processed is circulated through the processing zone to adsorb the removed components to the adsorbent of the rotor. The adsorbent is desorbed by circulating heated air through the regeneration zone.

Such a rotary suction device also has the same problems as those of the prior art shown in FIGS.
JP 2002-282654 A

  The present invention has been made in consideration of the above prior art, and maintains the concentration and temperature of the concentrated gas produced by desorbing the removed components of the gas to be treated at an optimum constant value corresponding to the catalyst. An object of the present invention is to provide a gas treatment system that efficiently desorbs a removed component from an adsorbent and treats the removed removed component.

According to the first aspect of the present invention, the adsorption-treated degassed air after the removal component of the gas to be treated is adsorbed by the adsorbent of the adsorbing portion is exhausted, and heated air is supplied to the adsorbent from the adsorbent. In the gas processing system for desorbing the removed component to generate a concentrated gas, catalytically burning the concentrated gas to process the removed component, and heat-exchanging the treated degassed air and the concentrated gas. a concentrator for circulating heated air to the suction unit when desorption of the adsorbent, and a density detection device for detecting the concentration of the enriched gas at the time of desorption is provided by the concentration of enriched gas detected by the concentration detection device, the suction portion The operation of the concentrator is controlled so that the concentration of the concentrated gas becomes an optimum concentration for the catalytic reaction, and the concentration detector is provided on a monitor passage provided for taking out the concentration detection gas from the adsorption section. And With the same catalyst as that processes serial enriched gas, to provide a gas processing system, characterized in that the determining arrangement the concentration of the enriched gas from the temperature difference between the inlet and outlet of the catalyst.

The invention of claim 2 is the invention of claim 1, provided the outdoor air needful air supply valve in the air passageway with an air passage for supplying desorption heated air to said suction unit, by the concentration detection device The opening and closing of the supply valve is controlled by the concentration of the concentrated gas .

The invention of claim 3 is characterized in that, in the invention of claim 1, a part of the combustion-treated degassed air after treating the concentrated gas with a catalyst is used as the desorption heated air.

The invention of claim 4 is characterized in that, in the invention of claim 1, a secondary adjustment unit for adjusting the concentration of the concentrated gas is provided upstream of the catalyst for processing the concentrated gas.

  According to the first aspect of the present invention, when the adsorbent is desorbed, the concentration of the desorbed gas that is desorbed and fills the adsorbing portion is controlled by a catalytic reaction by controlling the operation of the concentrating device while detecting the concentration of the concentrated gas in the adsorbing portion. The concentration of the concentrated gas fed to the catalyst can be kept constant. Therefore, the removal component can be treated with a high purification rate in the combustion process by the oxidation catalyst. In addition, a stable and constant temperature increase can be obtained by this catalytic reaction. For this reason, the amount of heat recovered by the heat recovery device is stabilized, and the inlet temperature of the concentrated gas sent to the catalyst thereafter can be maintained at a constant temperature optimum for the catalytic reaction. Thereby, the inlet temperature control to the catalyst is unnecessary or simple. In addition, since the reaction heat of the catalyst is heat-exchanged and reused, energy can be effectively used.

As described above, since the concentration and temperature of the concentrated gas can be maintained constant, the heating energy of the concentrated gas in the catalytic combustion section, which was necessary in the prior art, becomes unnecessary, and a great energy saving effect is obtained. In addition, since the same catalyst as the catalyst for processing the concentrated gas is provided in the concentration detection device on the monitor passage, the same conditions as the catalyst for processing the concentrated gas are reproduced in the concentration detection device to perform the catalytic reaction. Can be monitored. The concentration of the concentrated gas can be determined from the temperature difference between the inlet and outlet of the catalyst to be monitored, and the concentration of the concentrated gas can be controlled accordingly. Since the monitor passage connected to the adsorption section is always open, this acts as a relief passage, and even if the adsorption section is heated and the concentrated gas in the adsorption section starts volume expansion, the expanded concentrated gas is removed from the adsorption section. You can miss out. Therefore, the pressure in the adsorption portion does not increase and the concentrated gas does not leak to the outside.

  According to the second aspect of the present invention, when the adsorbent is desorbed, the supply valve is controlled to open and close according to the concentration of the concentrated gas in the adsorption section, and the amount of outside air is adjusted to feed the temperature of the desorption heated air and the catalyst. The concentration of the concentrated gas can be controlled. Thus, a concentrated gas having a constant optimum concentration can be supplied to the catalyst stably at the time of desorption, and a catalytic reaction with a high purification rate can be obtained.

  According to the invention of claim 3, since a part of the degassed air that has been heated after passing through the catalyst, which is originally exhausted, is used as the desorption heated air, the exhaust heat is efficiently used for heating. Energy can be reduced.

According to the invention of claim 4 , since the concentration of the concentrated gas for catalytic combustion is controlled in the adsorption portion and adjusted immediately before the catalyst, it is possible to eliminate the time lag and accurately maintain the predetermined concentration at the position of the catalyst. Therefore, temperature control using reaction heat of the catalyst can be performed accurately and easily.

  FIG. 1 is a diagram showing an outline of a processing system of the present invention. The thick solid line indicates the gas flow path during the adsorption process in which the gas component to be removed (removed component) contained in the gas to be treated (gas to be treated) such as harmful gas is adsorbed by the adsorbent, and the broken line is the adsorption The gas flow path at the time of the desorption process which detach | leaves the removed removal component from adsorption agent is shown. Further, the black arrow indicates the flow of gas containing the removed component, and the white arrow indicates the flow of gas not containing or removed the removed component.

  The adsorbing unit 2 is provided with an adsorbent made of activated carbon, zeolite, or the like that adsorbs the removal component of the gas to be treated. In the adsorption unit 2, for example, the optimum type and amount of the adsorbent according to the removed component are set so that the removed component can be removed from the gas to be processed with an adsorption efficiency of 95% or more.

  In the adsorbing unit 2, a heated air air passage 2 a that introduces outside air by opening and closing a desorption heated air supply valve 10 and a concentrated gas air passage that sends the concentrated gas to the processing device 3 through the heat recovery device 4. 2c is connected. The processing device 3 includes an oxidation catalyst, and removes the removed components in the sent concentrated gas by catalytic combustion. Further, a concentration device 5 that circulates heated air in the adsorption unit 2 to desorb a removed component from the adsorbent, and a concentration detection device 6 that detects the concentration of the desorption gas in the adsorption unit 2, respectively, are a circulating air passage 2b, It is connected to the suction part 2 through the monitor passage 2d.

  Hereinafter, the processing procedure of the gas to be processed by the processing system 1 of FIG. 1 will be described.

  Processed gas containing removed component gas such as isopropyl alcohol and toluene discharged at various factories is sent to the adsorbing unit 2 and cleaned after adsorbing the removed component on the adsorbent, for example, 95% or more. The degasified air is exhausted to the outside.

  When the adsorption process is stopped at night or the like, the desorption process of the removed component adsorbed by the adsorbent in the adsorption unit 2 is performed as follows. When the adsorption process is continued for 24 hours, a plurality of adsorption units 2 may be provided to switch between the adsorption unit that performs the adsorption process and the adsorption unit that performs the desorption process.

  Concentrator 5 is used at the start of the desorption process. That is, at the start of desorption, since there is almost no removed component desorbed from the adsorbent, the gas concentration in the adsorption unit 2 is low and does not reach the concentration required by the processing device 3. Therefore, even if this low-concentration gas is sent as it is to the processing apparatus 3, sufficient catalytic combustion cannot be obtained, and the degassing air temperature at the catalyst outlet after combustion does not reach the required temperature. Therefore, the processing apparatus 3 must be heated by a heater to increase the catalyst inlet temperature and promote catalyst combustion.

  Such a state in which the gas concentration in the adsorbing portion 2 is low is eliminated as time elapses, and as desorption proceeds, the concentration gradually increases and a concentrated gas having a necessary concentration can be obtained. However, since the concentration gradually changes until then, it is necessary to control the heating of the catalyst inlet temperature by the heater in accordance with the concentration change.

  Therefore, in this embodiment, when desorption is started, the gas concentration in the adsorption unit 2 is rapidly increased, a concentrated gas having a predetermined concentration is quickly generated, and the generated concentrated gas having an appropriate concentration is sent to the processing device 3. . Therefore, since the concentrated gas having a predetermined concentration is sent to the processing device 3 from the beginning, a sufficient catalytic combustion action can be obtained.

  The concentrating device 5 has a heating function and an air blowing function, and causes the air heated to about 40 ° C. to 100 ° C. to flow through the circulation air passage 2 b and to circulate between the adsorption unit 2. Thereby, the adsorption | suction part 2 is heated gradually and the removal component which adsorb | sucked to adsorption agent desorbs from adsorption agent. Thereby, the density | concentration of the desorbed removal component with which the inside of the adsorption | suction part 2 is filled rises, and concentrated gas is produced | generated.

  A part of the concentrated gas in the adsorption unit 2 is sent to the concentration detector 6 through the monitor passage 2d. In the concentration detection device 6, it is determined whether or not the concentration of the concentrated gas generated by desorption in the adsorption unit 2 has reached a concentration at which the catalytic combustion of the processing device 3 can be sufficiently effectively performed.

  When the concentrated gas having the required concentration is obtained, the operation of the concentration device 5 is stopped, and the concentrated gas is supplied from the adsorption unit 2 to the processing device 3 through the heat recovery device 4.

  The degassed air that has been heated by catalytic combustion in the processing device 3 is subjected to heat exchange with the concentrated gas in the heat recovery device 4 to increase the temperature of the concentrated gas, and then discharged to the outside. In addition, degassing air means the gas (usually air) after receiving an adsorption action or a catalytic action through an adsorbent or a catalyst.

  Hereinafter, the operation at the time of detachment of the system through the processing device 3 will be further described.

  The degassed air that leaves the processing device 3 and passes through the heat recovery device 4 is sucked by the fan 7 and discharged to the outside through the atmosphere opening unit 8.

  A part of the degassed air exhausted from the atmosphere opening part 8 is adsorbed to the atmosphere opening part 8 through the air passages 2e and 2a. It is supplied into the section 2 and desorbs again to circulate through the heat recovery device 4 and the processing device 3. Such circulation of the degassed air is performed by the fan 7. That is, the atmosphere opening portion 8 is at a positive pressure because it is on the discharge side of the fan 7, and degassed air is released to the atmosphere. On the other hand, the suction side of the fan 7 communicates with the processing device 3, the heat recovery device 4, and the adsorption unit 2 through a closed air passage system that is not released to the atmosphere, and further communicates with the air intake 9 through the air passages 2 a and 2 e. To do. Therefore, the air intake 9 of the desorption air passage 2e has a negative pressure, and a part of the discharged degas air is sucked. At this time, the air intake 9 is arranged in the range of the positive pressure of the atmosphere opening portion 8 so that outside air is not sucked from the air intake 9.

  Thus, by using the degassed air after catalytic combustion as the desorption heating air, the heating of the desorption heating air sent to the adsorption unit 2 becomes unnecessary or reduced, and the energy is reduced.

  Outside air is introduced into the heating air passage 2 a through the air supply valve 10. When the concentration of the concentrated gas in the adsorption unit 2 detected by the concentration detector 6 is higher than necessary, or when the temperature is higher than necessary, the air supply valve 10 is opened to generate heated air having an appropriate temperature. Then, this is sent to the adsorption unit 2. The concentrated gas generated by desorption in the adsorption unit 2 is supplied to the processing device 3. It is desirable that the air supply valve 10 be capable of adjusting the flow rate according to the concentration and temperature in the adsorption unit 2.

  FIG. 2 is a schematic diagram showing the internal structure of the density detector 6. When the concentrated gas is generated in the adsorption unit 2 (FIG. 1), a small amount of the concentrated gas is taken from the adsorption unit 2 to the concentration detection device 6 by the fan 21 or the pump.

  The concentration detection device 6 has an oxidation catalyst 25, temperature sensors 24 and 26 provided on the inlet side and the outlet side thereof, and various controls based on the detection values of the temperature sensors 24 and 26 connected to the temperature sensors 24 and 26. The regulators 23 and 27 to perform and the heater 22 to heat the taken-in gas are provided. The catalyst 25 is the same as the catalyst in the processing apparatus 3.

  In general, since the oxidation catalyst has a feature that the chemical reaction is promoted as the temperature is higher, the concentrated gas taken into the concentration detection device 6 can be sufficiently converted into the catalyst 25 by any kind of gas when entering the catalyst 25. For example, it is heated by the heater 22 until it reaches 300 ° C. so as to react. This temperature control is performed by controlling the heater 22 with a regulator 23 connected to the inlet side temperature sensor 24 of the catalyst 25.

  A concentrated gas having a predetermined temperature is passed through the catalyst 25, the temperature of the gas detected by the outlet side temperature sensor 26 is compared with the temperature detected by the inlet side temperature sensor 24, and the concentrated gas is calculated based on the temperature rise value due to catalytic combustion. Is determined by the outlet-side regulator 27. For example, when the temperature difference between the inlet and the outlet is 100 ° C., when the concentration is suitable for sending the concentrated gas to the treatment process, the outlet temperature of the gas entering the catalyst 25 at 300 ° C. is 400 ° C. If so, it is determined that the optimum density has been reached. The regulator 27 determines whether the temperature is higher or lower than 400 ° C., and transmits a control signal to the supply valve 10 for introducing outside air. The concentrated gas that has passed through the catalyst 25 is exhausted to the atmosphere as it is.

  Incidentally, a flow rate adjusting valve 11 is provided on the air passage 2e (FIG. 1), and the opening / closing control is performed in conjunction with the air supply valve 10 to adjust the flow rate of the outside air and degassed air having a temperature higher than that, thereby the adsorbing portion. The concentration inside the gas 2 may be controlled to adjust the concentration of the concentrated gas.

  When the adsorption unit 2 is gradually heated by the start of the operation of the concentrating device 5, the gas in the adsorption unit 2 gradually begins to expand in volume, but has expanded because the monitor passage 2d to the concentration detection device 6 is always open. The gas can escape to the outside of the adsorption unit 2. Therefore, the pressure in the adsorption unit 2 does not increase excessively from the initial low concentration to the optimum concentration.

  The processing apparatus 3 includes an oxidation catalyst such as platinum for catalytically burning the concentrated gas and a heating unit. When the concentrated gas is subjected to catalytic combustion, a large difference occurs in the catalytic reaction action depending on the temperature of the gas.

  FIG. 3 shows the change in the purification rate depending on the inlet temperature to the catalyst when the gas is catalytically combusted. This curve varies depending on the type of gas and its concentration. FIG. 3 shows the measurement results for 250 ppm isopropyl alcohol and 537 ppm toluene. In the case of isopropyl alcohol, a purification rate of approximately 95% or more can be obtained when it is put into the catalyst at 220 ° C. or higher. In the case of toluene, the purification rate increases abruptly when the temperature exceeds 170 ° C., and a purification rate of about 95% is obtained at 180 ° C. or higher, and 98% or higher when 200 ° C. is exceeded. Therefore, for example, when removing toluene, even if it is put in the catalyst at 150 ° C. or lower, the removal effect is hardly obtained. Thus, in order to process the removal component, it is necessary to put it in the catalyst at an appropriate temperature with a high purification rate.

  The value of the temperature rise after combustion differs depending on the type of gas and its concentration. For example, a temperature rise of 68 ° C. is obtained for 1000 ppm isopropyl alcohol and 133 ° C. for toluene.

  Therefore, if the concentration of the concentrated gas fed into the processing apparatus 3 in FIG. 1 is set to a constant value, for example, 1000 ppm, the temperature rise value after oxidation combustion by the catalyst is fixed. Moreover, the inlet temperature to the catalyst for obtaining a desired purification rate is determined by the type of gas. For example, when isopropyl alcohol having a concentration of 1000 ppm and a temperature of 250 ° C. is passed through the catalyst, about 95% of the isopropyl alcohol is purified at the outlet of the catalyst and the temperature is increased by 68 ° C.

  Hereinafter, in the processing system 1 of FIG. 1, a predetermined purification rate will be obtained when it is put into the catalyst at 250 ° C., and the processing procedure of the concentrated gas that rises by 100 ° C. at 1000 ppm due to catalytic combustion will be described.

  The gas in the adsorption unit 2 is concentrated by the concentrating device 5, and the concentrated gas controlled to 1000 ppm by the concentration detecting device 6 is sent to the heat recovery device 4 at 50 ° C., for example. In the initial stage where heat exchange by the heat recovery device 4 cannot be performed, the concentrated gas at 50 ° C. is heated to 250 ° C. with a heater or the like and then put into the catalyst. When catalytic combustion occurs, the temperature rises by 100 ° C. due to the generation of reaction heat, the removed components of the concentrated gas are removed, and the degassed air at 350 ° C. is discharged from the processing device 3. The discharged degassed air enters the heat recovery device 4 and is reduced in temperature to, for example, 150 ° C. by heat exchange to raise the concentration gas from 50 ° C. to 250 ° C. Thereby, heating with a heater becomes unnecessary. If this state is maintained, it is not necessary to heat the concentrated gas at the catalyst inlet temperature to 250 ° C., and a great energy saving effect can be achieved.

  The 150 ° C. degassed air that has passed through the heat recovery device 4 is discharged into the atmosphere by the fan 7 as described above, and a part thereof is returned to the adsorption unit 2 through the air passage 2e. Since the appropriate heating temperature of the adsorption unit 2 is about 60 ° C. to 100 ° C., the air supply valve 10 is controlled to mix with air, and the temperature is lowered and sent to the adsorption unit 2.

  The concentration gas generated in the adsorption unit 2 is such that the concentration is precisely 1000 ppm and the inlet temperature is 250 ° C. so that catalytic combustion in the processing device 3 is performed with the maximum reaction efficiency. 6 and the concentrator 5 and the air supply valve 10 are controlled.

  In this way, the heat of reaction by the catalyst is reused by using the heat recovery device 4, and the concentration of the concentrated gas sent from the adsorption unit 2 to the processing device 3 is controlled to be constant so that the processing system 1 can self-circulate. The removal component of the gas to be treated can be removed and the energy required for heating can be greatly reduced. Since the inlet temperature necessary for the catalyst to sufficiently react and the temperature rise value due to catalytic combustion vary depending on the type of gas, the temperature and concentration are controlled according to the type of gas to be removed.

  FIG. 4 shows a different embodiment of the present invention, in which a secondary adjustment unit 12 is provided in order to further improve the concentration detection accuracy of the concentrated gas.

  Since a certain amount of distance is separated between the adsorption unit 2 and the concentration detection device 6, a time lag occurs between when the sample for monitoring the concentrated gas is taken out from the adsorption unit 2 and when the concentration is detected. At the start of desorption, even if a predetermined concentration and temperature are reached on the inlet side of the adsorbing unit 2, the concentration and temperature are low on the outlet side. Therefore, a time lag occurs until the concentrated gas having an appropriate concentration and temperature reaches the processing device 3. Due to such a time lag, even if concentration control of the concentrated gas is performed by the concentration detection device 6, a state where the concentrated gas having an appropriate concentration is not supplied to the processing device 3 occurs. In addition, after the optimum concentration is detected, the concentration action may continue and the concentration of the concentrated gas may become higher than necessary.

  Therefore, in the example of FIG. 4, the secondary adjustment unit 12 is provided between the adsorption unit 2 and the heat recovery device 4 to further adjust the concentration of the concentrated gas.

  FIG. 5 shows the internal configuration of the secondary adjustment unit 12. The concentrated gas sent to the secondary adjustment unit 12 is temporarily stored in the buffer tank 31. For example, a concentration detection device 33 having the same configuration as the concentration detection device 6 shown in FIG. 2 is provided in the secondary adjustment unit 12, and a part of the concentrated gas flowing out from the buffer tank 31 and flowing into the heat recovery device 4 is taken in. Detect density with. When the concentration is higher than the predetermined concentration, the outside air introduction valve 32 is opened, and the outside air is mixed and diluted. Thereby, the concentrated gas of predetermined concentration can be sent into the processing apparatus 3. Further, by providing the buffer tank 31, it is possible to suppress the concentration of the concentrated gas from being increased.

  Normally, after the concentration is determined by the concentration detection device 6, the concentrated gas is sent out from the adsorption unit 2 in a state where the concentration is slightly increased. Therefore, if the concentration is reduced by dilution in the secondary adjustment unit 12, the concentration will be exactly the predetermined concentration. Although it can be adjusted, the density control by the density detector 6 may be set slightly higher than a predetermined density.

  All the steps other than readjusting the density by the secondary adjustment unit 12 are the same as in the example of FIG. By providing the secondary adjustment unit 12 immediately before the heat recovery apparatus 4, the concentration accuracy of the concentrated gas can be further improved and the catalytic combustion effect can be accurately maintained.

  The present invention can be applied to a system in which harmful gas discharged from a factory or the like is adsorbed with an adsorbent, and then adsorbed harmful components are desorbed and burned with an oxidation catalyst.

Schematic which shows embodiment of this invention. Schematic which shows the internal structure of the density | concentration detection apparatus of FIG. The graph which shows the relationship between the inlet_port | entrance temperature to a catalyst, and the purification rate of to-be-processed gas. Schematic which shows different embodiment of this invention. Schematic which shows the internal structure of the secondary adjustment part of FIG. Schematic which shows a prior art example. Schematic which shows the conventional different example.

Explanation of symbols

1: treatment system, 2: adsorption section, 2a: heated air passage, 2b: circulating air passage, 2c: concentrated gas air passage, 2d: monitor passage, 2e: air passage, 3: treatment device, 4: heat Recovery device, 5: Concentration device, 6: Concentration detection device, 7: Fan, 8: Air release unit, 9: Air intake port, 10: Air supply valve, 11: Flow rate adjustment valve, 12: Secondary adjustment unit, 21 : Fan, 22: Heater, 23, 27: Regulator, 24, 26: Temperature sensor, 25: Catalyst, 31: Buffer tank, 32: Valve, 33: Concentration detector.

Claims (4)

Exhaust the degassed air that has been adsorbed after adsorbing the removal component of the gas to be adsorbed on the adsorbent of the adsorption unit, and supplying the heated air to the adsorbent to desorb the removal component and concentrate it In a gas processing system for generating a gas, catalytically burning the concentrated gas to process a removed component, and exchanging heat between the processed degassed air after the processing and the concentrated gas,
A concentrator that circulates heated air through the adsorber when the adsorbent is desorbed and a concentration detector that detects the concentration of the concentrated gas at the time of desorption are provided. Depending on the concentration of the concentrated gas detected by the concentration detector, adsorption is performed. Control the operation of the concentrator so that the concentration of the concentrated gas in the unit becomes an optimum concentration for the catalytic reaction,
The concentration detection device is provided on a monitor passage provided for taking out the concentration detection gas from the adsorption section, and includes the same catalyst as the catalyst for processing the concentrated gas. From the temperature difference between the inlet and the outlet of the catalyst, A gas processing system characterized in that the concentration of the concentrated gas is determined. An air passage for supplying heated air to be desorbed to the adsorption portion is provided, and an air supply valve for taking in outside air is provided in the air passage, and the opening and closing of the air supply valve is controlled by the concentration of the concentrated gas by the concentration detector. The gas processing system according to claim 1, wherein: The gas processing system according to claim 1, wherein a part of the combustion-treated degassed air after treating the concentrated gas with a catalyst is used as the desorption heated air.   The gas processing system according to claim 1, wherein a secondary adjustment unit that adjusts the concentration of the concentrated gas is provided upstream of a catalyst that processes the concentrated gas.

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