KR20050086038A - Adsorption/catalyst-oxidation voc removing system for low-concentration voc disposal - Google Patents

Abstract

The present invention proposes an optimal adsorption-catalyst oxidation system for economically treating low-volume volatile organic compounds (VOCs), and a hydrophobic zeolite adsorbent and a VOC oxidation catalyst capable of selectively adsorbing and concentrating VOCs. The purpose is to implement a more economical system by reducing the energy demand required to heat excess air during thermal or catalytic incineration of low concentration VOC streams by implementing on one system.

In the present invention, a hydrophobic zeolite adsorbent and a VOC oxidation catalyst are implemented on one system. In the present invention, first, an independent adsorbent layer and an oxidation catalyst layer are used to concentrate VOC, which is usually discharged at a low concentration, in the adsorbent layer, and then gradually warmed up and desorbed to oxidize. Independent adsorption / catalyzed VOC removal system that decomposes and removes in catalyst layer, and secondly, integrated dual function adsorption / catalytic oxidation that occurs periodically by adsorption and catalytic oxidation in one adsorption / catalyst layer incorporating catalytic function into hydrophobic zeolite adsorbent A VOC removal system is proposed.

Description

Adsorption / catalyst-oxidation VOC removing system for low-concentration VOC disposal}

The present invention relates to volatile organic compound (VOC) treatment technology through adsorption and catalytic oxidation, and more particularly, among volatile organic compound discharge sources, such as various industrial processes, laundry, printing, painting facilities and gas stations The technical approach is to first adsorb and concentrate low concentration VOCs during normal VOC effluent using adsorbents that have affinity for VOCs, and secondly concentrated VOCs. By using an excellent oxidation catalyst to decompose into substances that are harmless to the human body.

Volatile Organic Compound (VOC) is a generic term for hydrocarbon compounds with a vapor pressure of 10 ^-2 kPa or more. Heterogeneous hydrocarbons (eg, aldehydes, ketones, etc.) are included, and most of them are not only harmful to the human body but also cause substances of urban smog, such as air pollution, water pollution, odors, and environmental hormones. Cause problems.

VOC material removal techniques generally used to solve the above problems include recovery techniques such as adsorption, condensation, absorption, membrane separation, and thermal incineration. Removal techniques such as thermal incineration, catalytic incineration, UV-oxidation and biofitration have been applied.

These techniques should be selected based on the composition and concentration of the compound, economics, energy supply capacity, process operation and maintenance capacity, and the most suitable removal process.

The adsorption method, incineration method (heat or catalyst), and adsorption / incineration hybrid method, which are most widely used among the various treatment techniques, have the following characteristics.

The adsorption method is a method of removing using an adsorbent such as activated carbon or zeolite, which requires less installation cost than the thermal incineration method and the catalytic incineration method.

In particular, VOC adsorption removal using activated carbon has been most widely used because of its high adsorption capacity due to the high surface area of activated carbon.

However, due to the disadvantages that activated carbon has ignition, refractory properties, and humidity control (<50% RH) of the processing gas prior to application to the process, in recent years, the need for humidity control along with high surface area and thermal stability is required. Free (<96% RH) hydrophobic zeolites have been suggested as promising adsorbents.

Thermal incineration is a method of directly burning and removing VOCs at high temperatures (700-1100 ° C), which can handle a large amount of VOCs, but it is uneconomical for heavy load fluctuations, low concentrations, and low flow rates.

Further, when the recalcitrant VOC substances in exhaust gas present increases the combustion temperature and driving rain picked relatively large, since the reaction temperature is high, the nitrogen in the high temperature combustion air through an oxidation reaction of the secondary air pollutants NO _X (Thermal NO _X ), The system is relatively large, the installation area is difficult to expand due to the large installation area.

Catalytic incineration is a method of burning VOC material from a fixed source by burning it with a catalyst, which is suitable for the removal of relatively low concentration of organic matter, and can effectively remove VOC material at a very low reaction temperature compared to high temperature combustion method. There is a characteristic.

Since the reaction temperature is low, the operation cost is low and economical, and there is an advantage that little NO _x is generated. In addition, there is an advantage that the system is easy to expand the equipment is simple.

The adsorption / incineration hybrid method is a method in which a low concentration of VOC is concentrated by adsorption followed by incineration with heat or a catalyst, and has both advantages of the adsorption method and the incineration method, and demand is gradually increasing with the strengthening of environmental regulations.

Therefore, the development of a system that can increase the removal efficiency of the VOC in accordance with gradually increasing environmental regulations is required.

An object of the present invention devised to solve the above problems is to provide an adsorption / catalyst incineration system using a hydrophobic zeolite having a large Si / Al ratio as an adsorbent in order to more effectively remove VOCs emitted at low concentrations.

It is still another object of the present invention to provide an adsorption / catalyst incineration system using a dual function adsorption catalyst which is an adsorbent incorporating various metal elements into the zeolite and has catalytic performance.

The present invention relates to the implementation of an adsorption / catalyst incineration apparatus for economically treating VOCs at low concentrations of VOC sources. The present invention provides a catalyst for a standalone adsorption / catalyzed VOC removal system having a hydrophobic zeolite adsorbent layer and an oxidizing catalyst layer, and a hydrophobic zeolite adsorbent We propose two systems of integrated dual function adsorption / catalyzed VOC removal system through dual function adsorption / catalyst with components.

In order to achieve the above object, the present invention provides a device capable of purifying one or more volatile organic compound (VOC) vapors through adsorption and catalytic oxidation, and contaminated air having a blower motor to receive contaminated air containing VOC. Intake fan; A dust collector for physically removing fine dust from the air introduced through the contaminated air intake fan; An adsorption unit having an adsorbent layer capable of adsorbing and concentrating VOCs in the air passing through the dust collector, and heating means for heating the desorbable VOCs to the adsorbent layer; A catalytic oxidation and exhaust unit capable of discharging the air from which the VOC supplied from the adsorption unit is removed in the adsorption mode at room temperature, and catalytically oxidizing the VOC supplied from the adsorption unit in the desorption mode in a catalyst layer heated by a heating unit; A polluted air intake passage connecting the polluted air intake fan and a dust collector; An adsorption part introduction passage connecting the dust collector and the adsorption part; An adsorption part discharge passage connecting the adsorption part to the catalytic oxidation and exhaust part; And an adsorption fan controller for adjusting the air suction amount of the suction fan, an adsorption bed temperature controller for controlling the heating means of the adsorption unit, and a temperature controller for controlling the heating means of the catalyst layer. Removal system.

Another invention is an apparatus capable of purifying one or more components of volatile organic compound (VOC) vapor through adsorption and catalytic oxidation, including an air suction nozzle capable of locally introducing contaminated air containing VOCs; A dust collector for physically removing fine dust from the air introduced through the air suction nozzle; An adsorption unit connected to the dust collector and having an adsorbent layer capable of adsorbing and concentrating VOCs in the air passing through the dust collector, and heating means for heating to desorb the VOC adsorbed on the adsorbent layer; A polluted air intake fan installed after the adsorption unit and having a blower motor to receive polluted air containing VOCs; Installed after the intake fan to discharge the air from the VOC is removed from the adsorption unit in the adsorption mode at room temperature, and in the desorption mode can be catalytically oxidized VOC supplied from the adsorption unit in the catalyst layer heated by the heating means Catalytic oxidation and exhaust; A movable wheel capable of moving the system; And an adsorption fan controller for adjusting the air suction amount of the suction fan, an adsorption bed temperature controller for controlling the heating means of the adsorption unit, and a temperature controller for controlling the heating means of the catalyst layer. Removal system.

The adsorbent layer is preferably composed of a hydrophobic zeolite that selectively adsorbs only volatile organic compounds in competitive adsorption with water.

The hydrophobic zeolite is preferably a mixture of at least one structure of MFI (HZSM-5) or FAU (HY) or Mordenite (HMOR) or Beta (H-Beta).

In the above, the adsorbent layer is preferably configured to include a hydrophobic zeolite characterized by a desorption temperature range of 18 to 300 ℃.

The catalyst layer preferably comprises a catalyst having a VOC oxidation temperature range of 100 to 500 ° C.

Another invention for achieving the above object is a device capable of purifying one or more volatile organic compound vapors by the simultaneous action of adsorption and catalytic oxidation using a dual function adsorption catalyst to receive contaminated air containing VOC. Polluted air intake fan having a blowing motor; A dust collector for physically removing fine dust except for VOC components of air introduced through the contaminated air intake fan; A four-way valve having a valve direction controller for selecting one of an upflow and a downflow by selecting an injection direction of VOC-containing air passing through the dust collector; Dual function adsorption catalyst system comprising at least three or more temperature-controlled dual function adsorption catalyst layer capable of adsorbing VOC in the upflow or downflow VOC-containing air introduced through the four-way valve and simultaneously catalytically desorption ; A polluted air intake passage connecting the polluted air intake fan and a dust collector; A dust collector exit passage connecting the dust collector and the four-way valve; Two input / output flow paths connecting the four-way valves to respective inlets and outlets of the upper and lower ends of the dual function adsorption catalyst system; An exhaust passage connecting the four-way valve and the exhaust unit; And the contaminated air suction fan blower motor regulator, each dual function adsorption catalyst bed temperature controller, and a valve direction controller.

The dual function adsorption catalyst is preferably composed of a hydrophobic zeolite having a large Si / Al ratio on which a catalytic oxidation active component of a noble metal or a transition metal, which is an adsorbent and exhibits catalytic oxidation reaction activity, is supported.

The hydrophobic zeolite is preferably a mixture of at least one structure of MFI (HZSM-5) or FAU (HY) or Mordenite (HMOR) or Beta (H-Beta).

The catalytically active component contained in the hydrophobic zeolite preferably contains at least one or more of a noble metal such as Pt or Pd or a transition metal such as Cu, Co, Cr, Mn, Fe, Ag, Ni, or the like.

The dual function adsorption catalyst is preferably in the operating temperature range of 18 to 100 ℃ in the adsorption mode, the operating temperature range of 18 to 500 ℃ in the desorption and catalytic oxidation mode.

In the dual function adsorption catalyst system, the dual function adsorption catalyst is composed of at least three layers, and there is a heating means between the layers, so that the upper or lower portion of the adsorption catalyst can be heated according to the direction of upflow or downflow. It is desirable to have independent temperature control.

It is preferable that the four-way valve is connected to a direction controller for changing the flow direction at the same time as the desorption termination after the predetermined adsorption time has elapsed in accordance with the adsorption capacity of the dual function adsorbent.

Hereinafter, the present invention will be described in detail with reference to the drawings and examples.

FIG. 1 is a flowchart of a standalone adsorption / catalyzed VOC removal system 10 in which an adsorbent layer and a VOC oxidation catalyst layer are separated, and FIG. 2 is a structural diagram of a small capacity mobile processing apparatus 30 using the same.

Referring to the process of low concentration, high flow VOC flow is processed through the flow chart of Figure 1 as follows.

First, the standalone VOC removal system is divided into three parts: the suction and pretreatment unit, the adsorption unit 13, the catalytic oxidation and the exhaust unit 14.

The suction and pretreatment unit includes an intake fan 11 and a dust collector 12.

The adsorption part 13 includes a hydrophobic zeolite adsorbent layer 15, a desorption heat exchanger or heating line 16, an adsorbent layer temperature controller 20, and a temperature signal line 28.

The catalytic oxidation and exhaust unit 14 includes a catalyst layer 17 capable of oxidizing VOC, a heat exchanger or heating line 18 for catalytic oxidation, a catalyst bed temperature controller 21 and a temperature signal line 29. .

The operation is performed by repeating the adsorption mode and the desorption-catalytic oxidation mode periodically.

In operation in adsorption mode, contaminated air 22 containing VOCs is injected into the removal system through contaminated air intake fans 11, such as blowers that can regulate the flow rate.

The injected contaminated air enters the dust collector 12 through the contaminated air suction passage 23.

The particulate matter contained in the air is removed through the dust collector 12, enters the adsorption section 13 through the adsorption section introduction passage 24, and then passes through the adsorbent layer 15 maintained at a low temperature. And removed.

At the time of adsorption, the temperature of the adsorbent layer 15 is maintained at an adsorption temperature of low temperature (room temperature ~ 100 ° C).

The VOC-removed flow through the adsorption of the adsorbent layer 15 enters the catalytic oxidation and exhaust portion 14 through the adsorption part discharge passage 25.

In the adsorption mode operation, the catalytic oxidation and exhaust 14 maintain a low temperature (room temperature ~ 100 ° C) and are in an inactive state in which catalysis does not occur.

The flow through the inert catalyst bed 17 is discharged to the atmosphere as a purified air stream 26.

After operating in the adsorption mode for an appropriate adsorption operation time suitable for the adsorption capacity of the adsorbent layer 15, the mode is switched to the desorption-catalyzed oxidation mode. Operation of the desorption-catalyst oxidation mode is as follows.

The air 22 input for the operation of the desorption-catalyzed oxidation mode does not necessarily need to use purified air.

In the adsorption mode, the low concentration of VOC-air, which was the flow to be removed, can be used. This is because even if some VOC is present in the input flow, it will be oxidized together with the VOC desorbed from the adsorbent layer 15 in the catalyst layer 17 at the final stage of the catalytic oxidation.

The air introduced through the contaminated air intake fan 11 or the low concentration of VOC-air flows into the dust collector 12 through the contaminated air intake passage 23 and then the adsorption portion 13 through the adsorption portion introduction passage 24. Is led to.

In the adsorption unit 13, the temperature of the adsorption-concentrated VOCs in the adsorption mode is elevated and desorbed through the temperature controller and the heat exchanger or the heating line 16.

The temperature range of the adsorption layer for desorption is in the middle temperature (room temperature ~ 300 ℃) range and is adjusted according to the interaction of the adsorbent and the VOC.

Since the desorbed VOC should be oxidized and removed from the catalyst layer 17, it should not exceed an appropriate concentration for safety of operation before entering the catalyst layer 17.

This action is applied to the flow rate control signal of the air sent by the blower motor controller 19 through the blower motor control signal line 27, and the temperature increase rate control signal sent by the adsorbent layer temperature controller 20 through the temperature signal line 28. As a result, the VOC concentration of the adsorption part discharge passage 25 is not exceeded the lower explosive limit (LEL).

The catalytic oxidation and the desorption flow transferred to the exhaust part 14 through the adsorption part discharge passage 25 are catalytically oxidized in the catalyst layer 17.

The catalyst oxidation temperature is determined according to the type of catalyst and the main treatment VOC, and the catalyst bed temperature controller 21 is controlled in the oxidation operation temperature range of 100 to 500 ° C. through the temperature signal line 29.

The adsorbent layer 15 and catalyst layer 17 used in the stand-alone adsorption / catalyzed VOC removal system may be of the pellet type and the honeycomb type, but the honeycomb type adsorbent layer and the catalyst layer are somewhat preferred for the application of low concentration high flow rate. Do.

A hydrophobic zeolite having a structure of MFI (HZSM-5), FAU (HY), Mordenite (HMOR), Beta (H-Beta), or the like is applied to the adsorption layer according to the target VOC to be removed or mixed.

However, when there is little water in the flow, an adsorbent such as activated carbon may be used in addition to the hydrophobic zeolite.

In the catalyst layer, a pellet or honeycomb type catalyst in which precious metals such as Pt and Pd, transition metals such as Cu, Co, Cr, Mn, Fe, Ag, and Ni are supported on alumina or hydrophobic zeolite as a single component or multiple components is used.

FIG. 2 shows a schematic diagram of a simple small capacity mobile standalone adsorption / catalyzed VOC removal system 30 applying the principles of FIG. 1.

A small device using the movable wheel 32 allows partial intake of contaminated air 22 through the fluid air intake nozzle 31.

In the adsorption mode operation, the external air 22 is sucked through the suction motor 35 and the blowing fan 34.

The VOC-air stream 37 first purified using the dust collector 12 and the air filter 33 passes through the honeycomb adsorbent layer 15 in the adsorption section 13 and the VOC is adsorbed and removed.

At this time, the adsorption temperature is maintained at a low temperature (normal temperature ~ 100 ℃) by adjusting the desorption heat exchanger or heating line 16 by the adsorbent bed temperature controller 20 connected to the temperature signal line (28).

After adsorption, the purified air 38 exiting through the blower fan 34 passes through the catalyst layer 17 adjusted to low temperature (room temperature ~ 100 ° C) and exits to the exhaust port 36. Reference numeral 26 denotes a finally purified air stream.

The blowing fan 34 is operated by the suction motor 35, the suction motor is controlled by the blower motor controller 19 connected to the blowing motor control signal line (27).

After operating in the adsorption mode for an appropriate adsorption operation time suitable for the adsorption capacity of the adsorbent layer 15, the mode is switched to the desorption-catalyzed oxidation mode.

In the desorption-catalytic oxidation mode, the adsorption unit 13 is heated and desorbed, and the catalytic oxidation and exhaust unit 14 are maintained at an oxidation operation temperature (100 to 500 ° C.) to cause the catalytic decomposition reaction of the desorbed VOC.

Pellet type and honeycomb type may be applied to the adsorbent layer 15 and the catalyst layer 17 used in the small-capacity mobile stand-alone adsorption / catalyzed VOC removal system. Somewhat preferred.

A hydrophobic zeolite having a structure of MFI (HZSM-5), FAU (HY), Mordenite (HMOR), Beta (H-Beta), or the like is applied to the adsorption layer according to the target VOC to be removed or mixed. In the catalyst layer, a pellet or honeycomb type catalyst in which precious metals such as Pt and Pd, transition metals such as Cu, Co, Cr, Mn, Fe, Ag, and Ni are supported on alumina or hydrophobic zeolite as a single component or multiple components is used.

Example 1

3 shows an adsorption breakthrough curve of toluene, which is one of the representative VOCs.

Table 1 shows the types and physical properties of the hydrophobic zeolites used in the adsorption breakthrough.

Kinds N ₂ adsorption data Si / Al ₂ surface area [m ² / g] pore volume [cm ³ / g] FAU (HY) 80 753 0.54 Mordenite (HMOR) 90 553 0.33 MFI (HZSM-5) 280 393 0.24 Beta (H-Beta) 300 661 0.39 Activated Carbon (A.C.) 936 0.73

All adsorbent samples were pretreated for 2 hours under a helium stream at 400 ° C to remove impurities, including water, which may be present on the surface.

After pretreatment, the sample was cooled to room temperature (27 ° C) and maintained for about 1 hour.

As the analytical gas used for adsorption, a mixed gas of toluene 1000 ppm was used for high purity air. Adsorption was carried out by flow at 27 ° C. until breakthrough occurred until C / Co was maintained at 1.

Samples used for adsorption ranged from 0.03 to 0.05 g, and all samples were sized 125-250 μm to make constant the effect of diffusion.

In FIG. 3, HZSM-5 (10 rings: 5.1 to 5.6 kPa) and HMOR (12 rings: 7.0 to 6.5 kPa, 8 rings: 2.6 to 5.7 kPa) that have a small pore size show a small adsorption amount and a large pore size HY. (12 rings, 7.4 Å) and H-Beta (12 rings: 5.6 to 7.7 Å) show a relatively large adsorption amount. In particular, the adsorption breakthrough is more ideal in the case of HY which has a pore size of about 13 Å.

Example 2

Saturated adsorbed hydrophobic zeolite samples in Example 1 were left under constant helium flow to remove condensed toluene in pores or between particles, and then heated at a rate of temperature increase of 5 ° C./min under constant flow (20 SCCM). Desorption experiment was performed.

In the case of HY zeolite having excellent adsorption properties, it can be seen that desorption occurs at a relatively lower temperature (less than 100 ° C.) than other zeolites.

Activated carbon showed excellent results in the adsorption characteristics of Example 1, but the desorption characteristics shown in FIG. 4 are not as good as those of zeolite in terms of the detachable temperature.

In Example 1, HY zeolite exhibiting adsorption characteristics close to activated carbon occurs rapidly in a low desorption and narrow temperature range. Such desorption characteristics are superior to activated carbon when applied to a system in which adsorption and desorption must be repeated.

Example 3

Example 3 is a water-toluene bicomponent adsorption breakthrough and hydrothermal desorption experiments on hydrophobic zeolite HY and hydrophilic NaX adsorbent.

Actually, the workplace where the VOC treatment is to be carried contains a large amount of water, and most of the VOCs to be treated are not multi-components but single components.

Therefore, to determine the effect of water on the adsorption performance of the zeolite, the two-component adsorption breakthrough experiment was conducted.

Toluene and water were controlled by micro injection pump, respectively, to maintain an appropriate concentration (1000 ppm of toluene, 10% relative humidity).

The binary system was stirred in a mixer filled with quartz beads to pass through the adsorbent bed in a uniform flow.

Post-adsorption flow was monitored for concentration changes in real time through quadrupole mass.

The adsorbent used in the experiment was 0.1 g powder and the flow rate was maintained at 250 ml / min. All samples were pretreated for 2 hours at 300 ° C. under airflow before adsorption.

The adsorbents used in the experiments were hydrophobic HY zeolites and hydrophilic NaX zeolites.

5 and 6 show toluene monocomponent breakthrough and bicomponent adsorption breakthrough curves of hydrophobic HY zeolite and NaX zeolite, respectively.

The curve labeled 'dry' in the figure shows the breakthrough and temperature increase and desorption experiments of the toluene single component alone, and the curve labeled 'wet' indicates the breakthrough of toluene and water in a stream in which the moisture content is maintained at 10% relative humidity (H) and The temperature desorption experiment is shown.

In Figure 5 it can be seen that the shape of the toluene monocomponent adsorption breakthrough for the hydrophobic HY zeolite shows the same pattern as the flow of conditions containing water.

This is because HY, a hydrophobic carrier, has excellent hydrophobic properties and selectively adsorbs only toluene.

The breakthrough curve of the water indicates that most of the water is excluded from the adsorbent at the beginning of the adsorption.

On the other hand, in NaX zeolite, a hydrophilic adsorbent in FIG. 6, the breakthrough pattern shows the opposite trend.

Hydrophilic adsorbents such as NaX showed satisfactory adsorption performance in water-free streams, while adsorption of toluene was completely excluded due to the action of water to compete with toluene in water-containing streams.

Therefore, in order to apply to a workplace containing a lot of water, it is essential to use a hydrophobic zeolite having a characteristic of selectively adsorbing only VOC when competing adsorption with water.

Example 4

7 is a breakthrough curve obtained upon adsorption of a single component (toluene) on HY-coated cordierite honeycomb (400 cell / in ² ) adsorbent.

The flow used for adsorption was about 140 ppm of toloene flow of 5.05 L / min flow, and four 400 cell / in ² cordierite honeycombs having a diameter of 55 mm and a height of 74 mm were used.

The hydrophobic HY zeolite coating amount of each honeycomb was about 13.5 g and the total zeolite content was 54 g.

The breakthrough time obtained in FIG. 7 was about 1000 minutes.

When the amount of toluene treated up to the time is converted into g, it is about 3 g.

8 is a breakthrough curve obtained as a result of a two-component (water-toluene) adsorption experiment for the same honeycomb adsorbent. The introduction of moisture was controlled to about 7000 ppm.

The breakthrough time obtained in FIG. 8 was slightly reduced to about 800 minutes. However, considering that the treatment flow was 6.05 L / min, about 3 g of toluene was also treated.

In the case of the adsorbent HY / cordierite honeycomb, the selective VOC adsorption characteristic of the hydrophobic zeolite was preserved, so that it was found that the adsorption capacity was not lost even in the condition where the moisture content was considerable.

Example 6

Example 6 is a temperature desorption experiment on cordierite honeycomb adsorbent coated with HY.

Desorption of the adsorption-concentrated VOCs at an appropriate space velocity and concentration stream for the operating conditions of the catalytic reactor is an important parameter in designing the adsorption / desorption system. This is because, if the concentration to be desorbed is too high can have a significant impact on the safety of the catalytic reaction.

The LEL of toluene is 12000ppm. At higher concentrations, the safety of the system cannot be guaranteed due to the risk of ignition.

Therefore, maintaining the concentration of the desorption flow at an appropriate line by controlling the speed of the desorption air flow or the rate of temperature increase is essential for flexible and safe system operation.

9 and 10 are experiments showing an example of adjusting the concentration of the desorption flow by adjusting the temperature rise rate of the reactor at a constant flow rate 3L / min of the toluene adsorbed honeycomb adsorbent.

From the information that most of the desorption takes place between about 60 to 100 ℃ in Figure 9 in the experiment of Figure 10 it was able to adjust so as not to exceed the desorption flow concentration of 6000ppm by slowly adjusting the temperature increase rate of this section.

Next, another invention, an integrated dual function adsorption / catalyzed VOC removal system, is described.

11 and 12 are flow charts of the integrated dual function adsorption / catalyzed VOC removal system 39 where FIG. 11 is the case where the VOC-air flow passes upward through the dual function adsorption / catalyst bed and FIG. 12 shows that the VOC-air flow is dual This is the case where the functional adsorption / catalyst layer passes downward.

Switching of the upstream and the downflow is performed by driving the four-way valve 41 connected by the valve direction controller 50 and the valve direction control signal line 51.

The principle of continuous adsorption / catalysis of low concentrations of VOC-air streams is as follows.

The adsorption mode starts with either the upstream (FIG. 11) or the downstream flow (FIG. 12).

First, the adsorption proceeds from the upward flow of FIG. 11.

Outside polluted air 22 is introduced into the system through the polluted air intake fan (11).

The introduced contaminated air is introduced into the dust collector 12 through the contaminated air suction passage 23 and fine particles are removed from the dust collector 12.

The polluted air flow from which the fine particles from the dust collector exit passage 40 are removed is led to the lower I / O passage 42 by the direction selection of the four-way valve 41.

The VOC-air stream entering the dual function adsorption / catalytic oxidation system 47 from the bottom input and output flow passage 42 is contacted and adsorbed from the bottom of the dual function adsorbent / catalyst layers 451,452, 453, 454, 455, 456.

In FIG. 11 and FIG. 12, only six dual function adsorbent layers are shown for convenience. However, in practical applications, the operating principle is the same in all systems having three or more layers, and the number of layers is determined by variables such as adsorption capacity, time, and desorption time. The associated design variable.

The adsorption temperature in the dual function adsorption / catalytic oxidation system 47 is maintained constant through the heating wires 461,462,463,464,465,466,467 between each adsorbent / catalyst layer, and the heating wires 461,462,463,464,465,466,467 are connected to the temperature controller 49 by the temperature signal line 49. Is maintained at a fixed adsorption temperature (normal temperature to 100 ° C).

As adsorption proceeds, the dual function adsorbent / catalyst bed begins to saturate adsorption from the bottom.

The air flow from which VOC is removed by adsorption passes through the upper I / O flow path 43 and flows to the exhaust flow path 44 by the direction selection of the four-way valve 41 to be discharged into the atmosphere.

The adsorption process takes place within the adsorption capacity of the dual function adsorbent / catalyst layers (451,452,453,454,455,456) and saturation of the VOC proceeds from the bottom to the top.

The adsorption process is allowed to proceed until the VOC adsorption of the uppermost dual function adsorbent / catalyst layer starts. The time of this adsorption process can be estimated from the adsorption capacity of the dual function adsorbent / catalyst bed.

At the end of the adsorption process, it is converted to desorption / catalytic oxidation. The desorption / catalytic oxidation process is an upward flow desorption / catalytic oxidation mode in which the uppermost adsorbent / catalyst layer is heated and the heating layer moves to the bottom.

Initially, 461 and 462 of the heating wires are heated so that the uppermost adsorbent / catalyst layer 451 reaches the catalytically degradable temperature (100-500 ° C.).

After the temperature of the uppermost adsorbent / catalyst layer 451 reaches an appropriate catalytic oxidation temperature, the temperature of the adsorbent / catalyst layer 452 adjacent to the lower end is gradually raised by heating the heating wire 463 to reach the catalytic oxidation temperature.

At this time, the VOC adsorbed on the adsorbent / catalyst layer 452 is desorbed before reaching the catalyst oxidation temperature, and the desorbed VOC is decomposed into water and carbon dioxide by the catalytic decomposition of the upper adsorbent / catalyst layer 451.

After all the VOC adsorbed on the adsorbent / catalyst layer 452 has been desorbed and catalyzed by the upper adsorbent / catalyst layer 451, the temperature of the adsorbent / catalyst layer 453 is gradually raised by heating the heating wire 464 and the adsorbent / catalyst layer ( 451) stops the catalytic oxidation temperature to be naturally cooled.

The VOC desorbed from the adsorbent / catalyst layer 453 is catalytically decomposed in the adsorbent / catalyst layer 452, and air containing the decomposition product water and carbon dioxide contacts the adsorbent / catalyst layer 451 to cool the layer and discharge it to the atmosphere. .

As described above, the adsorbed VOC is catalytically oxidized simultaneously with desorption while sequentially moving the heating layer to the lower end. As the heating layer descends from the top to the bottom, the adsorbent / catalyst layer on the top, which was initially heated, is naturally cooled to adjust to the adsorption temperature (room temperature ~ 100 ° C).

After the movement of the heating layer is completely finished to the lower end, the direction of the four-way valve 41 is changed to start the downward flow adsorption mode as shown in FIG. 12.

In the downflow adsorption mode, as in the upflow adsorption mode, it occurs within the adsorption capacity of the dual function adsorbent / catalyst layers 451,452,453,454,455,456, but the VOC saturation of the adsorbent / catalyst layer is from the top to the bottom.

Adsorption is allowed to proceed for a calculated time just before VOC adsorption of the lowest bifunctional adsorbent / catalyst bed begins.

At the end of the adsorption, the process is desorbed / catalyzed. The desorption / catalytic oxidation process is performed in a downward flow desorption / catalytic oxidation mode in which the lowermost adsorbent / catalyst layer is heated and the heating layer is sequentially moved to the upper layer as opposed to the upflow desorption / catalytic oxidation mode.

In the downflow desorption / catalytic oxidation mode, the VOC desorbed at the top is decomposed by the adsorbent / catalyst at the bottom and discharged into the atmosphere. When the downflow desorption / catalytic oxidation mode ends, the flow returns to the upstream adsorption mode, which was the original operation.

Therefore, the overall continuous process consists of upstream adsorption, upflow desorption / catalytic oxidation, downflow adsorption, downflow desorption / catalytic oxidation, and upflow adsorption mode.

The inlet air used in the adsorption mode and the desorption / catalytic oxidation mode is the same low concentration of VOC-contaminated air, and the flow rate is compared with the adsorption mode to maintain the catalyst bed inlet concentration in the desorption / catalytic oxidation mode at the proper concentration for system safety and optimal operation. In order to control the heating layer moving speed in conjunction with the blower motor control signal line (27) can be adjusted through the blower motor controller (19).

The dual function adsorbent / catalyst layer used in the integrated dual function adsorption / catalyzed VOC removal system as shown in Figs. 11 and 12 may be applied to the pellet type and the honeycomb type, but the honeycomb type adsorbent / catalyst layer is applied to the low concentration high flow rate. This is somewhat desirable.

The number of stages of the adsorbent / catalyst layer can be adjusted according to design variables such as the throughput of VOC, the operating time of adsorption mode and desorption / catalytic oxidation mode.

The adsorbent / catalyst layer used in the systems of FIGS. 11 and 12 is an adsorbent and a bifunctional adsorbent / catalyst exhibiting catalytic oxidation activity, and a hydrophobic zeolite having a large Si / Al ratio carrying an oxidation catalyst component of a noble metal or a transition metal to be.

The zeolite can be applied to the hydrophobic zeolites having the structures of MFI (HZSM-5), FAU (HY), Mordenite (HMOR), Beta (H-Beta), etc., respectively or mixed according to the VOC to be removed. As the catalyst component contained therein, noble metals such as Pt and Pd or single or multi-component materials of transition metals such as Cu, Co, Cr, Mn, Fe, Ag, and Ni can be used.

The present invention as described above provides a method for treating the existing low concentration of VOC with high energy efficiency compared to the catalytic oxidation treatment. The first method is to apply the hydrophobic zeolite itself as an independent VOC adsorbent and use it as a standalone adsorption / catalyzed VOC removal system as shown in Figures 1 and 2, and in a second, more advanced form, Pt, A dual function adsorbent / catalyst carrying precious metals such as Pd and VOC catalyst components such as Cu, Co, Cr, Mn, Fe, Ag, Ni, etc., is incorporated into the integrated dual function adsorption / catalyzed VOC removal system shown in Figs. It is applied to treat low concentration VOC more effectively.

1 is a stand-alone adsorption / catalyzed VOC removal system

2 is a small capacity mobile stand-alone adsorption / catalyzed VOC removal system

3 is a toluene adsorption breakthrough curve on a hydrophobic zeolite adsorbent.

4 is a toluene temperature rise and desorption curve on a hydrophobic zeolite adsorbent.

5 is a toluene-water binary adsorption breakthrough curve on a hydrophobic HY zeolite.

6 is a toluene-water binary adsorption breakthrough curve on NaX zeolite.

Figure 7 shows the toluene monocomponent adsorption breakthrough curves on a hydrophobic HY zeolite adsorbent coated on a 400cell cordierite honeycomb.

8 is a toluene-water binary adsorption breakthrough curve on a hydrophobic HY zeolite adsorbent coated on a 400cell cordierite honeycomb.

9 is a toluene temperature rise and desorption curve of a hydrophobic HY zeolite adsorbent coated on a 400 cell cordierite honeycomb (temperature control condition I).

Figure 10 shows the toluene temperature desorption curve on a hydrophobic HY zeolite adsorbent coated on a 400cell cordierite honeycomb (temperature control condition II).

11 is an integrated dual function adsorption / catalyzed VOC removal system (upflow)

12 is an integrated dual function adsorption / catalyzed VOC removal system (downstream).

<Description of Symbols for Major Parts of Drawings>

10: stand-alone adsorption / catalyzed VOC removal system 11: contaminated air intake fan

12: dust collector 13: adsorption part

14: catalytic oxidation and exhaust 15: adsorbent layer

16: desorption heat exchanger or heating line 17: catalyst bed

18: Heat exchanger or heating line for catalytic oxidation 19: Blower motor controller

20: adsorbent bed temperature controller 21: catalyst bed temperature controller

22: Contaminated air flow with VOC 23: Contaminated air inlet flow path

24: flow path for adsorption part 25: flow path for adsorption part

26: Purified air flow 27: Blowing motor control signal line

28: 29: temperature signal line

30: Small capacity mobile standalone adsorption / catalyzed VOC removal system

31: air suction nozzle 32: movable wheel

33: air filter 34: blowing fan

35: suction motor 36: exhaust port

37: VOC-Air Flow

38: Purified air or desorbed VOC-air flow after adsorption

39: Integrated dual function adsorption / catalyzed VOC removal system

40: dust collector discharge passage 41: 4-way valve

42: lower I / O channel 43: upper I / O channel

44: exhaust passage

451,452,453,454,455,456: dual function adsorbent / catalyst bed

461,462,463,464,465,466,467: heat exchanger or heating wire

47: dual function adsorption / catalytic oxidation system 48: temperature controller

49: temperature signal line 50: valve direction regulator

51: valve direction control signal line

Claims (13)

A device capable of purifying one or more volatile organic compound (VOC) vapors through adsorption and catalytic oxidation, and a contaminated air intake fan having a blower motor to receive contaminated air containing VOC; A dust collector for physically removing fine dust from the air introduced through the contaminated air intake fan; An adsorption unit having an adsorbent layer capable of adsorbing and concentrating VOCs in the air passing through the dust collector, and heating means for heating the desorbable VOCs to the adsorbent layer; A catalytic oxidation and exhaust unit capable of discharging the air from which the VOC supplied from the adsorption unit is removed in the adsorption mode at room temperature, and catalytically oxidizing the VOC supplied from the adsorption unit in the desorption mode in a catalyst layer heated by a heating unit; A polluted air intake passage connecting the polluted air intake fan and a dust collector; An adsorption part introduction passage connecting the dust collector and the adsorption part; An adsorption part discharge passage connecting the adsorption part to the catalytic oxidation and exhaust part; And Independent adsorption / catalytic oxidation VOC removal comprising a suction fan controller for adjusting the air suction amount of the suction fan, an adsorption bed temperature controller for controlling the heating means of the adsorption unit, a temperature controller for controlling the heating means of the catalyst bed system. An apparatus for purifying one or more volatile organic compound (VOC) vapors through adsorption and catalytic oxidation, wherein the apparatus includes an air suction nozzle capable of locally introducing contaminated air containing VOCs; A dust collector for physically removing fine dust from the air introduced through the air suction nozzle; An adsorption unit connected to the dust collector and having an adsorbent layer capable of adsorbing and concentrating VOCs in the air passing through the dust collector, and heating means for heating to desorb the VOC adsorbed on the adsorbent layer; A polluted air intake fan installed after the adsorption unit and having a blower motor to receive polluted air containing VOCs; Installed after the intake fan to discharge the air from the VOC is removed from the adsorption unit in the adsorption mode at room temperature, and in the desorption mode can be catalytically oxidized VOC supplied from the adsorption unit in the catalyst layer heated by the heating means Catalytic oxidation and exhaust; A movable wheel capable of moving the system; And Independent adsorption / catalytic oxidation VOC removal comprising a suction fan controller for adjusting the air suction amount of the suction fan, an adsorption bed temperature controller for controlling the heating means of the adsorption unit, a temperature controller for controlling the heating means of the catalyst bed system. 3. The standalone adsorption / catalyzed VOC removal system of claim 1 or 2, wherein the adsorbent layer comprises a hydrophobic zeolite that selectively adsorbs only volatile organic compounds in competitive adsorption with water. 4. The standalone adsorption / catalyzed VOC of claim 3 wherein the hydrophobic zeolite is a mixture of at least one structure of MFI (HZSM-5) or FAU (HY) or Mordenite (HMOR) or Beta (H-Beta). Removal system. 3. The standalone adsorption / catalyzed VOC removal system of claim 1 or 2, wherein the adsorbent layer comprises a hydrophobic zeolite characterized by a desorption temperature condition of 18 to 300 ° C. 3. The standalone adsorption / catalyzed VOC removal system of claim 1 or 2, wherein the catalyst layer comprises a catalyst having a VOC oxidation temperature range of 100 to 500 ° C. A contaminated air intake fan having a blower motor for receiving contaminated air containing VOCs as a device capable of purifying at least one component of volatile organic compound vapors by a simultaneous action of adsorption and catalytic oxidation using a dual function adsorption catalyst; A dust collector for physically removing fine dust except for VOC components of air introduced through the contaminated air intake fan; A four-way valve having a valve direction controller for selecting one of an upflow and a downflow by selecting an injection direction of VOC-containing air passing through the dust collector; Dual function adsorption catalyst system comprising at least three or more temperature-controlled dual function adsorption catalyst layer capable of adsorbing VOC in the upflow or downflow VOC-containing air introduced through the four-way valve and simultaneously catalytically desorption ; A polluted air intake passage connecting the polluted air intake fan and a dust collector; A dust collector exit passage connecting the dust collector and the four-way valve; Two input / output flow paths connecting the four-way valves to respective inlets and outlets of the upper and lower ends of the dual function adsorption catalyst system; An exhaust passage connecting the four-way valve and the exhaust unit; And The contaminated air suction fan blower motor regulator, each dual function adsorption catalyst bed temperature regulator, valve integrated regulator comprising a dual function adsorption catalyst oxidation, characterized in that it comprises a valve direction controller. The dual function adsorption catalyst of claim 7, wherein the dual function adsorber catalyst comprises an hydrophobic zeolite having a Si / Al ratio having a catalytic oxidation active component of a noble metal or a transition metal which is an adsorbent and exhibits catalytic oxidation activity. Adsorption Catalyst Oxidation VOC Removal System. The method of claim 8, wherein the hydrophobic zeolite MOC (HZSM-5) or FAU (HY) or Mordenite (HMOR) or beta (H-Beta) structure, characterized in that at least one mixture of dual-functional adsorption catalytic oxidation VOC Removal system. The method of claim 8, wherein the catalytically active component contained in the hydrophobic zeolite comprises at least one or more of noble metals such as Pt or Pd or transition metals such as Cu, Co, Cr, Mn, Fe, Ag, Ni, etc. Integrated dual function adsorption catalyst oxidation VOC removal system. The dual function adsorption catalyst oxidized VOC removal system according to claim 7, wherein the dual function adsorption catalyst has an operating temperature range of 18 to 100 ° C in adsorption mode and an operating temperature range of 18 to 500 ° C in desorption and catalytic oxidation mode. 8. The dual function adsorption catalyst system of claim 7, wherein the dual function adsorber catalyst comprises at least three layers of the dual function adsorption catalyst, and there is a heating means between the layers, so that the upper or the lower part of the adsorption catalyst according to the direction of the upflow or the downflow. Dual function adsorption catalyst oxidized VOC removal system, characterized in that the independent temperature control capable of heating. The dual function adsorption catalyst oxidation VOC removal system according to claim 7, wherein the four-way valve is connected to a direction controller for changing the flow direction at the same time as the desorption termination after the predetermined adsorption time has elapsed in accordance with the adsorption capacity of the dual function adsorbent. .