JPH06285322A - Method and device for recovering volatile organic material - Google Patents

Abstract

PURPOSE:To provide a method and device for recovering volatile organic materials by which the volatile organic materials are effectively recovered at a low cost. CONSTITUTION:Plural adsorbers 1, 2 packed with active carbon and incorporating heat transfer tubes 3, 4 are installed. Feeding pipes V11, V21 for volatile organic material contg. waste gas are connected to one end sides of the adsorbers 1, 2 respectively, and clean air discharging pipes V12, V22 are connected to the other end sides. Steam pipes V13, V23; V19, V29 are connected to heat transfer tubes 3, 4 respectively. Carrier air feeding pipes V14, V24 are connected to one end parts of the adsorbers 1, 2 respectively and carrier air discharging pipes V15, V25 are connected to the other end parts. The carrier air discharging pipes V15, V25 are connected to a condenser 6 and the gaseous phase of the condenser 6 is connected to one end sides of the adsorbers 1, 2 and the liquid phase is recovered as volatile organic materials 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for recovering volatile organic substances such as CFCs, tetrachloroethylene, gasoline and benzene from exhaust gas.

[0002]

2. Description of the Related Art In view of problems such as ozone layer destruction and carcinogenicity caused by volatile organic substances such as CFCs, development of a technique for adsorbing exhaust gas of volatile organic substances on activated carbon and recovering the same have been promoted. There is. As a conventionally proposed technique, for example, a technique of adsorbing a volatile organic substance on activated carbon and then using an electric heater to regenerate the activated carbon, or a technique of directly blowing water vapor onto the activated carbon is known.

[0003]

However, the technique for regenerating the activated carbon by the electric heater has a problem that the operating cost is remarkably high although the facility cost is low. In addition, in the technology to regenerate activated carbon by blowing steam directly into the activated carbon, it is necessary to separate the liquefied water vapor and the volatile organic substances by the difference in specific gravity. Since some volatile organic substances dissolve in water, it is necessary to treat water. There is also a problem that the components of the volatile organic substance are changed because some water dissolves in the volatile organic substance due to difficulty and the tank is corroded.
Therefore, it is an object of the present invention to provide a volatile organic substance recovery apparatus and method capable of inexpensively and effectively recovering a volatile organic substance.

[0004]

The present invention has been made to achieve the above object, that is, the first invention is to provide a plurality of adsorption towers filled with activated carbon and containing heat transfer tubes, each adsorption tower One end of the tower is connected to a supply pipe of exhaust gas containing a volatile organic substance, the other end is connected to a discharge pipe of purified air, each heat transfer pipe is connected to a steam pipe, and one end of each adsorption tower (the above-mentioned It may or may not be the same as the one end side or the other end side), and a carrier air supply pipe is connected to the other end, and a carrier air discharge pipe is connected to the other end, and the carrier air discharge pipe is connected to a condenser. And a vapor phase of the condenser is connected to the one end side of each adsorption tower to collect a liquid phase as a volatile organic substance. A second invention is a method for recovering a volatile organic substance using the recovery device according to the first invention, wherein the adsorption of the volatile organic substance is performed in a part of the plurality of adsorption towers. In addition, in the adsorption tower of the other part, the vapor is supplied to carry out heating recovery of the volatile organic substance, and the vapor is further supplied and the carrier air is supplied to forcibly recover the volatile organic substance. Is the method of collection. A third invention is a method for recovering a volatile organic substance using the recovery device according to the first invention, while adsorbing the volatile organic substance in a part of the plurality of adsorption towers. In addition, after recovering the volatile organic substance in the adsorption tower of the other part, the supply of the steam is stopped and the carrier air is supplied to cool the activated carbon of the adsorption tower of the other part. Is the method of collection.

A fourth aspect of the invention is a volatile organic substance recovery device in which a steam pipe is connected to each of the heat transfer pipes of the recovery device of the first invention and a cooling water pipe is further connected. A fifth aspect of the present invention is a method for recovering a volatile organic substance using the recovery device according to the fourth aspect, wherein during adsorption of the volatile organic substance in some of the plurality of adsorption towers. In addition, after collecting the volatile organic substances in the adsorption tower of the other part,
Supplying the cooling water and supplying the carrier air,
This is a method for recovering volatile organic substances by cooling the activated carbon in the adsorption tower of the other part. A sixth aspect of the present invention is a volatile organic substance in which a purified air discharge pipe of a part of the adsorption tower of the plurality of recovery apparatus of the first aspect of the invention is connected to an exhaust gas supply pipe of another adsorption tower. It is a recovery device. A seventh invention is a method for recovering a volatile organic substance using the recovery device according to the sixth invention, wherein the other part is provided while adsorbing the volatile organic substance in the part of the adsorption tower. After recovering the volatile organic substances in the adsorption tower, the supply of the water vapor is stopped, the purified air of the partial adsorption tower is supplied, and the activated carbon in the adsorption tower of the other part is cooled. It is a method of recovering organic substances. An eighth invention is that, in addition to connecting a steam pipe to each of the heat transfer pipes of the recovery device of the first invention, a cooling water pipe is further connected to the exhaust pipe for purifying air of some of the plurality of adsorption towers. Is a device for recovering volatile organic substances, which is connected to the exhaust gas supply pipe of the adsorption tower of the other part. A ninth invention is a method for recovering a volatile organic substance using the recovery device according to the eighth invention, wherein the other part is provided while adsorbing the volatile organic substance in the part of the adsorption tower. After the recovery of volatile organic substances in the adsorption tower, the cooling water is supplied and the purified air of the part of the adsorption tower is supplied to cool the activated carbon of the adsorption tower of the other part. It is a method of recovering organic substances.

[0006]

The present invention will be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention. In this embodiment, two adsorption towers 1,
2 is used, and the adsorption towers 1 and 2 are filled with activated carbon and have heat transfer tubes 3 and 4 built therein. Various types of activated carbon such as spherical, honeycomb, fibrous, cylindrical, and crushed carbon are used, but it is preferable to use small-diameter granular carbon that is inexpensive, has a high adsorption rate, and has a large adsorption capacity per volume. . Especially, the average particle size is 0.5 to 2.0.
φ mm is recommended. An exhaust gas inlet valve V1 is provided on one end side of each of the adsorption towers 1 and 2, that is, on the upper end side in this embodiment.
A supply pipe for an exhaust gas containing a volatile organic substance is connected via 1 and V21, and purified air outlet valves V12 and V22 are respectively provided on the other end side, that is, the lower end side in this embodiment.
A discharge pipe for purified air is connected to the blower 5 via the, and the purified air discharge pipe is connected to the blower 5 and then opened to the atmosphere. Further, the lower end side of the second adsorption tower 2 is connected to the upper end side of the first adsorption tower 1 via a cooling bypass valve V16, and similarly, the lower end side of the first adsorption tower 1 is connected to the cooling bypass valve V16.
It is connected to the upper end side of the second adsorption tower via 26. Water vapor inlet valves V13 and V2 are provided in the heat transfer tubes 3 and 4, respectively.
3, a water vapor supply pipe is connected, and a cooling water inlet valve V
A cooling water supply pipe is connected via 17, V27, a steam discharge pipe is connected via steam outlet valves V19, V29, and a cooling water discharge pipe is connected via cooling water outlet valves V18, V28. Has been done. Further, a carrier air supply pipe is connected to one end of each of the adsorption towers 1 and 2, that is, the upper end in the present embodiment via carrier air inlet valves V14 and V24, respectively, and the other end, that is, the present embodiment. In the example, carrier air outlet valves V15 and V2 are provided at the lower ends,
A carrier air discharge pipe is connected via 5. This carrier air discharge pipe is connected to the condenser 6,
The outlet of the condenser 6 is connected to the gas-liquid separator 7. The gas phase of the gas-liquid separator 7 is the exhaust gas inlet valve V1 of each adsorption tower 1, 2.
1, V21 is connected to the upstream side, and the liquid phase of the gas-liquid separator 7 is connected to the volatile organic substance tank 8.

This embodiment is constructed as described above,
The first method for recovering volatile organic substances using the recovery device according to this embodiment will be described below. First, as shown in FIG. 1, the first adsorption tower 1 is kept in a standby state, the exhaust gas inlet valve V21 and the purified air outlet valve V22 of the second adsorption tower are opened, the blower 5 is operated, and the second adsorption tower 2 is operated. Adsorbs volatile organic substances in exhaust gas. Next, when a sufficient amount of volatile organic substances are adsorbed in the second adsorption tower 2, the exhaust gas inlet valve V11 and the purified air outlet valve V12 of the first adsorption tower are opened as shown in FIG. The first adsorption tower is used together with the second adsorption tower for a certain period of time. Next, when the first adsorption tower 1 is stably used, as shown in FIG. 3, the exhaust gas inlet valve V21 and the purified air outlet valve V22 of the second adsorption tower are closed and the carrier air outlet valve V25 is opened. In addition, the steam inlet valve V23 and the same outlet valve V29 are opened. This makes the second
The volatile organic substance adsorbed in the adsorption tower is indirectly heated by steam and discharged to the condenser 6, and is separated into a gas phase and a liquid phase by the gas-liquid separator 7, and the gas phase is the first in service. The liquid phase is supplied to the adsorption tower and is collected in the volatile organic substance tank 8 as a volatile organic substance. After a certain period of time,
As shown in FIG. 4, the carrier air inlet valve V2 of the second adsorption tower
When 4 is opened, the volatile organic substance adsorbed in the second adsorption tower is forcibly discharged by the carrier air, and the volatile organic substance is forcibly recovered.

Then, when the volatile organic substances adsorbed in the second adsorption tower have been almost recovered after a certain time has passed, as shown in FIG. 5, the water vapor inlet valve V23 and the outlet valve V29 of the second adsorption tower are provided. When is closed, only carrier air flows through the second adsorption tower 2 to cool the activated carbon. Next, when the activated carbon of the second adsorption tower 2 is sufficiently cooled after a lapse of a certain time, the carrier air inlet valve V24 and the outlet valve V25 of the second adsorption tower 2
And are closed to keep the second adsorption tower in a standby state. This state corresponds to the state in which the first adsorption tower 1 and the second adsorption tower 2 are replaced in FIG. Thus, thereafter, while recovering the volatile organic substance by one of the adsorption towers, the other adsorption tower performs the recovery of the volatile organic substance and the cooling of the activated carbon, and by repeating this alternately in both adsorption towers, Volatile organic substances in exhaust gas can be continuously recovered. In this recovery method, the cooling water inlet valves V17, V27, the outlet valves V18, V28, and the cooling bypass valves 16, 26 are kept fully closed. Therefore, for this recovery method,
It is possible to provide a recovery device in which these valves and their piping are omitted.

Next, a second method for recovering a volatile organic substance using the recovery device will be described. In this recovery method, the cooling water outlet valves V18 and V28 are excluded as described later, and the operation of FIGS. 1 to 4 is the same as that of the first method. Then, when the volatile organic substances adsorbed in the second adsorption tower are almost recovered, as shown in FIG.
The steam inlet valve V23 and the outlet valve V29 of the adsorption tower are closed,
In addition, the cooling water inlet valve V27 and the outlet valve V28 are opened. Then, when the activated carbon of the second adsorption tower 2 is sufficiently cooled after a certain time has passed, the carrier air inlet valve V2 of the second adsorption tower 2
4, the same outlet valve V25 and cooling water inlet valve V27 are closed to keep the second adsorption tower in a standby state. The cooling water outlet valve V28 is
Next, the opening is maintained until steam is introduced to heat and discharge the volatile organic substances in the second cooling tower. According to the second recovery method, the activated carbon in the adsorption tower is cooled by the cooling water as well as the carrier air, so that the activated carbon can be rapidly regenerated. Also, the cooling bypass valves 16 and 2
Since 6 is kept fully closed, a recovery device without these valves and its piping can be used for this recovery method.

Next, a third method for recovering a volatile organic substance using the above recovery device will be described. In this recovery method, the operation of FIGS. 1 to 4 is the same as that of the first method. However, the purified air outlet valve of the adsorption tower during adsorption is to be opened halfway. Then, when almost all the volatile organic substances adsorbed in the second adsorption tower are recovered,
As shown in (4), the steam inlet valve V23 and the outlet valve V29 of the second adsorption tower are closed, the carrier air inlet valve V24 and the outlet valve V25 of the second adsorption tower are closed, and the cooling bypass valve V26 and the purified air outlet V22 are opened. After the lapse of the period, the purified air outlet valve V12 of the first adsorption tower 1 which was in the half open state is fully closed.
Next, when the activated carbon of the second adsorption tower 2 is sufficiently cooled after a certain period of time, the purified air outlet valve V12 of the first adsorption tower 1 is first half-opened, and after a certain period of time, the cooling bypass of the second adsorption tower 2 is performed. Second by closing the valve V26 and the purified air outlet V22
Keep the adsorption tower on standby. According to this third recovery method, the activated carbon in the adsorption tower is cooled by the air purified in another adsorption tower, so that the carrier air supply device and the condenser can be stopped during this cooling period. It is possible to reduce the operating cost. Also, cooling water inlet valves V17 and V2
7 and the outlet valves V18 and V28 of the same valve 7 are kept fully closed, a recovery device can be used without this valve and its piping for this recovery method.

Next, a fourth method for recovering volatile organic substances using the above recovery device will be described. In this recovery method, the cooling water outlet valves V18 and V28 are excluded as described later, and the operation of FIGS. 1 to 4 is the same as that of the first method. However, the purified air outlet valve of the adsorption tower during adsorption is to be opened halfway. When the volatile organic substances adsorbed in the second adsorption tower are almost recovered,
As shown in (4), the steam inlet valve V23 and the outlet valve V29 of the second adsorption tower are closed, the carrier air inlet valve V24 and the outlet valve V25 are also closed, and the cooling bypass valve V26 and the purified air outlet V22 are opened, and the cooling water inlet Same outlet valve V27 and outlet valve V28
Opened, and after a short period of time, half opened
The purified air outlet valve V12 of the adsorption tower 1 is fully closed. Next, when the activated carbon of the second adsorption tower 2 has been sufficiently cooled after a certain period of time, the purified air outlet valve V12 of the first adsorption tower is first half-opened, and after a certain period of time, the cooling bypass valve of the second adsorption tower. V26, purified air outlet V22, and cooling water inlet valve V2
7 is closed to keep the second adsorption tower in a standby state. The cooling water outlet valve V28 is kept open until next time steam is introduced to heat and discharge the volatile organic substances in the second cooling tower.
According to the fourth recovery method, the activated carbon in the adsorption tower is cooled not only by the carrier air but also by the cooling water, so that the activated carbon can be quickly regenerated, and the activated carbon in the adsorption tower is separated by another adsorption. Since it is cooled by the air purified in the tower, the carrier air supply device and the condenser can be stopped during this cooling period, and the operating cost can be reduced.

In the above embodiment, the carrier air inlet valves V14, V24 and the air outlet valves V15, V25 were connected to the upper and lower ends of the adsorption tower, respectively. You can also connect. Further, in the above embodiment, the case where the number of the adsorption towers is two is shown, but it is also possible to operate with three or more adsorption towers.

[0013]

According to the present invention, the volatile organic substances can be alternately adsorbed by a plurality of adsorption towers for regeneration by indirect heating, so that the volatile organic substances can be recovered inexpensively and effectively. be able to. In particular, the use of small-diameter granular charcoal, which has a high adsorption rate and a large adsorption capacity per volume, makes it possible to recover volatile organic substances more inexpensively and effectively.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the present invention.

FIG. 2 is a system diagram showing a switching start state of the first operation method.

[Fig. 3] Similarly, a system diagram showing a heating and discharging state.

[Fig. 4] Similarly, a system diagram showing a forced discharge state.

FIG. 5 is a system diagram showing the same cooling state.

FIG. 6 is a system diagram showing a cooling state of a second operating method.

FIG. 7 is a system diagram showing a cooling state of a third operating method.

FIG. 8 is a system diagram showing a cooling state of a fourth operating method.

[Explanation of symbols]

1, 2 ... Adsorption tower 3, 4 ... Heat transfer tube 5
… Blower 6… Condenser 7… Gas-liquid separator 8
Volatile organic substance tanks V11, V21 ... Exhaust gas inlet valves V12, V22 ... Purified air outlet valves V13, V23 ... Steam inlet valves V14, V24 ... Carrier air inlet valves V15, V25 ... Carrier air outlet valves V16, V26 ... Cooling bypass Valves V17, V27 ... Cooling water inlet valve V18, V28 ... Cooling water outlet valve V19, V29 ... Steam outlet valve

Claims (10)

[Claims] 1. A plurality of adsorption towers filled with activated carbon and containing heat transfer tubes are provided, one end of each adsorption tower is connected to a supply pipe of exhaust gas containing a volatile organic substance, and the other end is discharged with purified air. Connect the pipes, connect the steam pipes to each heat transfer pipe, connect the carrier air supply pipe to one end of each adsorption tower, connect the carrier air discharge pipe to the other end, and connect the carrier air discharge pipe A device for recovering a volatile organic substance, which is connected to a condenser, and a vapor phase of the condenser is connected to the one end side of each adsorption tower to recover a liquid phase as a volatile organic substance. 2. A method of recovering a volatile organic substance using the recovery device according to claim 1, wherein the adsorption of the volatile organic substance is performed in a part of the plurality of adsorption towers. Of the volatile organic substance for supplying the steam to heat and recover the volatile organic substance in another part of the adsorption tower, and further supplying the steam and supplying the carrier air to forcibly recover the volatile organic substance. Recovery method. 3. A method of recovering a volatile organic substance using the recovery device according to claim 1, wherein the adsorption of the volatile organic substance is performed in a part of the plurality of adsorption towers. , After recovering the volatile organic substances in the adsorption tower of the other part, supply of the water vapor is stopped and the carrier air is supplied to cool the activated carbon of the adsorption tower of the other part. Recovery method. 4. A steam pipe is connected to each heat transfer pipe,
The volatile organic substance recovery device according to claim 1, further comprising a cooling water pipe connected thereto. 5. A method of recovering a volatile organic substance using the recovery device according to claim 4, wherein the adsorption of the volatile organic substance is performed in a part of the plurality of adsorption towers. Of the volatile organic substance for cooling the activated carbon of the adsorption tower of the other part by supplying the cooling water and the carrier air after recovery of the volatile organic substance in the adsorption tower of the other part Recovery method. 6. The volatile organic substance recovery apparatus according to claim 1, wherein the purified air exhaust pipe of some of the plurality of adsorption towers is connected to the exhaust gas supply pipe of the other adsorption tower. 7. A method of recovering a volatile organic substance using the recovery device according to claim 6, wherein the adsorption of the volatile organic substance is carried out in one of the adsorption towers, After recovering the volatile organic substances in the adsorption tower, the supply of the water vapor is stopped, the purified air of the partial adsorption tower is supplied, and the activated carbon in the adsorption tower of the other part is cooled. How to recover the substance. 8. A steam pipe is connected to each heat transfer pipe,
A cooling water pipe is further connected, and a purified air discharge pipe of one of the plurality of adsorption towers is connected to an exhaust gas supply pipe of another adsorption tower.
The volatile organic substance recovery device described. 9. A method of recovering a volatile organic substance using the recovery device according to claim 8, wherein the adsorption of the volatile organic substance is carried out in one of the adsorption towers, After recovering the volatile organic substances in the adsorption tower, the cooling water is supplied and purified air of the partial adsorption tower is supplied to cool the activated carbon of the adsorption tower of the other part. How to recover the substance. 10. The activated carbon has an average particle size of 0.5 to 0.5.
The device for recovering a volatile organic substance according to claim 1, 4, 6, or 8, which has a length of 2.0 mm.