JP2021133281A - Volatile organic compound processing apparatus and method for operating the same - Google Patents

Abstract

To provide a volatile organic compound processing apparatus having multiple number adsorption towers in which the volatile organic compound is adsorbed on the adsorbent of the adsorption tower and then desorption steam is fed for desorption, in which the load on the combustion furnace is reduced.SOLUTION: For a predetermined period after introducing the desorption steam F during desorption, the discharged mixed gas K is introduced not into the combustion furnace 40 but into the other adsorption tower 11b, which is performing adsorption process, via the raw gas feed pipe for introducing the volatile organic compound-containing gas.SELECTED DRAWING: Figure 1

Description

The present invention relates to an apparatus for treating a volatile organic compound from a gas before discharging a gas containing the volatile organic compound, and an operation method thereof.

Exhaust gas generated from factories may contain volatile organic compounds that cause problems if they are discharged into the atmosphere as they are. In this case, the volatile organic compounds contained must be treated before the exhaust gas is discharged into the atmosphere. As a method for this, a volatile organic compound contained in the exhaust gas is adsorbed on the adsorbent by an adsorbent tower containing an adsorbent such as activated carbon, the concentration in the gas is reduced, and the gas is discharged to the atmosphere. After that, a suction / desorption method is generally used in which water vapor is introduced into the adsorption tower to desorb the volatile organic compounds from the adsorbent so that the adsorption tower can be reused and the volatile organic compounds are treated.

This utilizes the fact that the amount of adsorption of activated carbon that adsorbs volatile organic compounds basically depends on the temperature. The lower the temperature of activated carbon, the higher the amount of adsorption, and the higher the temperature, the lower the amount of adsorption. Therefore, the activated carbon is adsorbed at a low temperature, and when it is desorbed, it is heated to a high temperature. To desorb activated carbon at a high temperature, the amount of heat such as high-temperature desorption steam, high-temperature gas that burns fuel, and residual gas after evaporating water with the calorific value of the high-temperature gas to generate desorption steam is used. It is carried out to introduce the gas to have (Patent Document 1).

Further, in many cases, a plurality of adsorption towers are used in parallel. While the adsorption step of adsorbing the volatile organic compound is performed in one adsorption tower, the desorption step of desorbing the volatile organic compound from the adsorbent is performed in another adsorption tower. The adsorption tower that has been desorbed is used again in the adsorption step, and the adsorption tower that has completed the desorption step is subjected to the desorption step, so that adsorption can always be continued while rotating. Patent Document 2 describes a volatile organic compound processing apparatus having a plurality of adsorption towers (adsorption tanks).

Further, the adsorption tower immediately after the desorption step is completed is saturated with water vapor. Therefore, the treated gas that has passed through the adsorption tower immediately after the adsorption step is started after the desorption step has a large amount of water vapor, and there is a problem in releasing it to the outside of the system as it is. Patent Document 2 proposes that the gas released immediately after starting the adsorption step in one adsorption tower is temporarily introduced into the other adsorption tower and then released into the atmosphere. For that purpose, a cooling exhaust gas conduit (12, 14 in Patent Document 2) that connects the upper part and the lower part of the two adsorption towers is provided, and a cooling exhaust gas conduit 13 that connects the upper and lower cooling exhaust gas conduits 12 and 14 is provided. , It is proposed to install and operate each valve.

However, the volatile organic compounds desorbed by water vapor leave sufficient energy that can be recovered by burning. Therefore, the desorbed gas generated in the desorption step is generally introduced into a combustion furnace that supplies heat for generating steam to recover chemical energy (for example, Patent Document 3).

Japanese Unexamined Patent Publication No. 2014-168741 JP-A-55-124523 Japanese Unexamined Patent Publication No. 2016-175028

When the desorbed steam is introduced from the lower side to start heating the activated carbon in order to perform the desorption step, the activated carbon warms from the portion where the desorbed steam comes into contact. The contacted portion reaches about 100 ° C., but not all activated carbon is heated promptly, and the heated region gradually expands from the lower side to the upper side. The boundary between the activated carbon heated to 100 ° C. and the activated carbon before heating is clear, and when this boundary reaches the upper surface of the activated carbon, water vapor (cooled) and volatile organic compounds are adsorbed for the first time. It is discharged into the upper space of the tower. Most of the mixed gas discharged up to that point is the amount of gas that was originally in the adsorption tower pushed out by atmospheric pressure, and the temperature is not high, and the amount of volatile organic compounds contained is small.

If the discharged mixed gas is introduced into the combustion furnace for about 5 minutes from the start of this desorption, the recovery of chemical energy cannot be expected and the temperature of the combustion furnace will only decrease, and the fuel consumption will increase. Oops.

Therefore, the present invention avoids a temperature drop in the combustion furnace immediately after the start of desorption in a volatile organic compound processing apparatus that recovers energy by introducing the gas discharged from the adsorption tower into the combustion furnace in the desorption step, and is more efficient. The purpose is to realize the operation of a good volatile organic compound processing apparatus.

This invention
An adsorption tower that has an adsorbent accommodating part filled with an adsorbent that adsorbs volatile organic compounds, and can supply desorbed water vapor that is brought into contact with water vapor to desorb the volatile organic compounds from the adsorbent accommodating part. It is a volatile organic compound processing apparatus having a plurality of groups.
An operation is performed in which the mixed gas discharged from the start of the desorption step in one of the adsorption towers is introduced into another adsorption tower, and after the predetermined time elapses, the mixed gas is desorbed. The above-mentioned problem was solved by a volatile organic compound processing apparatus introduced into a combustion furnace for generating steam for use.

In particular,
It has a plurality of adsorption towers having an adsorbent accommodating portion filled with activated carbon capable of adsorbing volatile organic compounds and desorbing the volatile organic compounds by receiving steam for desorption.
Each of the adsorption towers
A raw gas introduction pipe branched from a raw gas supply pipe to which the raw gas containing the volatile organic compound is supplied, and
A steam discharge pipe connected to a combustion furnace for discharging the mixed gas containing the volatile organic compound desorbed by the desorbed steam to generate the desorbed steam, and
Is connected to the upper space above the adsorbent accommodating portion.
And,
A discharge pipe that discharges the treated gas from which the concentration of the volatile organic compound has been reduced by the activated carbon from the raw gas, and
A steam introduction pipe branched from the steam supply pipe to which the detached steam is supplied, and
Is connected to the lower space below the adsorbent accommodating portion.
Valves are provided at the points where each pipe is connected.
After performing an adsorption step of reducing the concentration of volatile organic compounds in the raw gas by adsorbing it on the activated carbon,
In performing the desorption step of desorbing the volatile organic compound from the activated carbon by bringing the desorption steam into contact with the activated carbon.
The adsorption tower that starts the desorption step closes the valve of the steam discharge pipe and opens the valve of the raw gas introduction pipe for a predetermined time from the introduction of the desorption steam, and then opens the valve of the raw gas introduction pipe for the predetermined time. After that, the control is executed so as to open the valve of the steam discharge pipe and close the valve of the raw gas introduction pipe.

That is, in the raw gas introduction pipe connected so that the raw gas can be introduced into each adsorption tower, the raw gas inlet valve connected to the one said adsorption tower that has started the desorption step and the other that performs the adsorption step. Both the raw gas inlet valve connected to the adsorption tower is temporarily opened. On the other hand, during that time, the steam outlet valve connected to the combustion furnace from the discharge port for discharging the introduced steam or thermal gas is closed for the one adsorption tower that has started the desorption process.

After that, when it is detected that the temperature near the end of the upper space side (water vapor outlet valve side) from the adsorbent accommodating part of the adsorption tower undergoing the desorption step has risen above a predetermined condition, the adsorbent is heated. It can be considered that the desorbed volatile organic compounds pass through the adsorbent and reach the upper space side. If it is heated to this point, the gas released thereafter is heated to an extent that the temperature drop is acceptable even if it is sent to the combustion furnace, and the desorbed volatile organic compounds are sufficiently contained, so that it is burned. If it is burned in a furnace, the effect of saving fuel can be fully exerted. Therefore, the valve of the raw gas introduction pipe connected to the one adsorption tower that has started the desorption step is closed, and the valve of the steam discharge pipe is opened. As a result, the mixed gas discharged after the subsequent desorption is sent to the combustion furnace. Such a step is performed every time the desorption step is started in each adsorption tower.

According to the present invention, with respect to an existing volatile organic compound processing device, the volatile organic compound can be simply changed by changing the software part of the control device that opens and closes and operates the valve without changing the large-scale piping and adsorbent. It is possible to reduce the amount of fuel consumed when operating the processing device.

Configuration example diagram of a volatile organic compound processing apparatus that executes the operation method according to the present invention. Opening and closing transition table of the valve of the main part during the operation of the volatile organic compound processing apparatus according to the present invention FIG. 1 is a diagram showing a gas flow in the initial desorption step.

Hereinafter, embodiments of the present invention will be described. The present invention is a volatile organic compound processing apparatus and an operation method thereof in which the concentration of a volatile organic compound-containing gas is reduced so that the gas can be discharged into the atmosphere, and the volatile organic compounds are adsorbed by an adsorbent. The adsorption towers 11a and 11b that adsorb with this processing device have activated carbon as an adsorbent, and the adsorbed volatile organic compounds can be desorbed from the adsorbent by contacting with heated steam, and the adsorbent can be used repeatedly. .. The desorbed volatile organic compounds are used as fuel for recovering and heating steam. FIG. 1 shows an example of an overall image of a processing apparatus that performs these series of cycles. Although the figure shows a processing apparatus having two adsorption towers 11a and 11b, a processing apparatus having three or more adsorption towers 11 may be used.

The volatile organic compound processed by the processing apparatus operated by the operation method according to the present invention is an organic compound that can be turned into a gas by heating at normal pressure, and a compound that is liquid at room temperature is particularly easy to be adsorbed. Examples thereof include hydrocarbon solvents such as alcohols having about 1 to 8 carbon atoms such as methanol, ethanol and isopropyl alcohol, and aromatic organic compounds such as toluene and benzene.

The individual adsorption towers 11 are square or cylindrical, and adsorbent accommodating portions 12a and 12b are provided inside the apparatus, which are filled with an adsorbent that adsorbs volatile organic compounds and can be desorbed by heating. Granular activated carbon can be used as the adsorbent. In order to pass through the inside of the adsorption tower 11 in the vertical direction, it must pass through the adsorbent accommodating portion 12. Both the bottom surface and the top surface of the adsorbent accommodating portions 12a and 12b are housed in the adsorbent tower 11.

Thermometers 15a and 15b are provided in the adsorbent accommodating portions 12a and 12b for accommodating the adsorbent in the adsorbent towers 11a and 11b, and are connected to a control device (not shown) for controlling the opening and closing of each valve. There is. The position where the thermometers 15a and 15b are installed is inside the adsorbent accommodating portions 12a and 12b filled with activated carbon, which are 10 cm or more and 20 cm or less from the upper surface and are buried in the activated carbon. Further, it is desirable that the horizontal position is as close to the center of the adsorbent as possible, and it is preferable that the cylindrical adsorption tower 11 is provided with thermometers 15a and 15b at positions close to the center of the axis.

The upper spaces 13a and 13b on the upper end side of the adsorbent accommodating portions 12a and 12b of the adsorption tower 11 are branched from the raw gas supply pipe 21 of the gas containing the volatile organic compound (hereinafter referred to as "raw gas") A. The raw gas introduction pipes 22 are connected to each other. Raw gas inlet valves 23a and 23b are provided at the introduction ports from the raw gas introduction pipe 22 to the upper spaces 13a and 13b, respectively. If the raw gas inlet valves 23a and 23b are open, the raw gas A is introduced from there.

The lower spaces 14a and 14b on the lower end side of the adsorbent accommodating portions 12a and 12b are connected to the discharge pipe 24 for discharging the treated gas B whose concentration is reduced by being adsorbed by the adsorbent. Has been done. Raw gas outlet valves 26a and 26b are provided at the discharge ports from the lower spaces 14a and 14b, respectively. If the raw gas outlet valves 26a and 26b are open, the treated gas B is discharged from there. The tip of the exhaust pipe 24 merges and is connected to the exhaust pipe 25. The tip of the exhaust pipe 25 leads to an exhaust blower 27 for discharging as exhaust C into the atmosphere.

Further, a steam introduction pipe 32 for introducing the detachable steam F is connected to the lower spaces 14a and 14b. Steam inlet valves 33a and 33b are provided at the introduction ports from the steam introduction pipe 32 to the lower spaces 14a and 14b, respectively. If the steam inlet valves 33a and 33b are open, the detachable steam F is introduced from the steam inlet valves 33a and 33b. The steam introduction pipe 32 branches from the steam supply pipe 31 to which the desorbed steam F is sent by the steam blower 43 described later, and is connected to the adsorption towers 11a and 11b, respectively.

Further, steam discharge pipes 34 for extracting the mixed gas K discharged from the adsorption towers 11a and 11b to which the detached steam F is sent are connected to the upper spaces 13a and 13b, respectively. Steam outlet valves 36a and 36b are provided at the discharge ports from the upper spaces 13a and 13b, respectively. If the steam outlet valves 36a and 36b are open, the mixed gas K extruded when the detachable steam F is introduced into the adsorption towers 11a and 11b is discharged. The mixed gas K is a gas in which cooled water vapor, combustion gas accompanied by water vapor, other gas, and desorbed volatile organic compounds are mixed at a rate that changes depending on the timing. The steam discharge pipe 34 merges and is connected to the combustion furnace supply pipe 35, through which the mixed gas K is conveyed to the combustion furnace 40.

In the combustion furnace 40, the fuel D is supplied to generate the high-heat combustion gas H used to turn the water E into steam and discharge it from the combustion furnace discharge pipe 41. In addition to the fuel D, the volatile organic compounds contained in the mixed gas K supplied through the combustion furnace supply pipe 35 are also burned to improve the energy efficiency of the entire processing apparatus.

Water E is sprayed onto a part of the combustion gas H to generate generated steam J in which the cooled combustion gas and the steam generated by heating are mixed. The rest of the combustion gas H is released into the atmosphere as exhaust gas G. This generated steam J is sent out by the steam blower 43, mixed with the boiler steam I generated by a separately provided steam boiler (not shown), and sent to the steam supply pipe 31 as deattached steam F. The steam supply pipe 31 branches and leads to the steam introduction pipe 32 connected to the lower spaces 14a and 14b of the adsorption towers 11a and 11b, respectively, and introduces the desorbed steam F into the adsorption towers 11a and 11b.

In the initial stage of the desorption step, not only the desorption steam F but also the high-temperature combustion gas H and the exhaust gas G may be mixed with the desorption steam F or introduced prior to the desorption steam F. Therefore, the processing apparatus may be provided with a line for spraying water on the combustion gas H shown in the figure and mixing the combustion gas H with steam.

When each valve is executed by the software of the control device, timer control or control by the sensor value is appropriately selected at the start of suction, the start of attachment / detachment, or other predetermined timings shown below. good. Although the valve may be switched manually, it is easier to operate it by automatic control based on time and numerical conditions during normal operation. Examples of the sensor include thermometers 15a and 15b embedded in the adsorbents 12a and 12b of the adsorption towers 11a and 11b. It is preferable to receive digital information from these sensors through a communication line and automatically control based on the digital information. Further, in an emergency, it may be possible to manually control them in preference to automatic control.

In the adsorption step for processing the raw gas A, the raw gas inlet valves 23a and 23b and the raw gas outlet valves 26a and 26b are opened for one of the adsorption towers 11a and 11b for performing the adsorption step, and the steam inlet valve 33a. , 33b and the steam outlet valves 36a, 36b are closed. As a result, the raw gas A is introduced into either the adsorption tower 11a or the adsorption tower 11b, and the raw gas A is ventilated to the activated carbon contained in the adsorbent accommodating portions 12a and 12b. Activated carbon adsorbs the volatile organic compounds contained in the raw gas A, and the treated gas B from which the volatile organic compounds have been removed is discharged from the discharge pipe 24. When the activated carbon sufficiently adsorbs the volatile organic compound and the calculated adsorption amount exceeds the permissible value, the adsorption process in the adsorption towers 11a and 11b is stopped and the process is switched to the desorption process.

Next, in the desorption step, in the adsorption towers 11a and 11b where the desorption step is performed, the raw gas inlet valves 23a and 23b and the raw gas outlet valves 26a and 26b are closed, and the steam inlet valves 33a, The 33b and the steam outlet valves 36a and 36b will be opened. As a result, the desorbed water vapor F is supplied to the adsorption towers 11a and 11b to be desorbed, the activated carbon contained in the adsorbent accommodating portions 12a and 12b is warmed, and the adsorbed volatile organic compounds are desorbed. .. When this desorption proceeds sufficiently, the adsorbent returns to a state where it can be adsorbed again. On the other hand, the mixed gas K containing the cooled water vapor and the desorbed volatile organic compound is discharged from the water vapor discharge pipe 34.

However, in the present invention, the valve opening / closing state is temporarily changed for a predetermined time from the start of the attachment / detachment process before the valve is opened / closed in the above-mentioned attachment / detachment step. The process in this state is called an initial desorption process. Specifically, the steam outlet valves 36a and 36b connected to the upper spaces 13a and 13b of the adsorption towers 11a and 11b for performing the desorption step are temporarily closed instead of being opened, and instead, the original The gas inlet valves 23a and 23b are temporarily opened. When the open / closed state of the valve is changed in this way, the mixed gas K extruded into the upper spaces 13a and 13b with the supply of the detached steam F is sent to the raw gas introduction pipe 22 instead of the combustion furnace 40. .. The raw gas A is sent to the raw gas introduction pipe 22 from the raw gas supply pipe 21, but the mixed gas K is pushed in from the adsorption towers 11a and 11b of the person performing the desorption step to the branch point P. Until then, the mixed gas K flows backward, and the mixed gas K is conveyed from the branch point P toward the other adsorption towers 11a and 11b along with the raw gas A. That is, the mixed gas discharged at the initial stage at the start of the desorption step is introduced into the adsorption towers 11a and 11b in which another adsorption step is being executed.

By performing this initial desorption step, the load applied to the combustion furnace 40 can be reduced. First, since the calorific value of the introduced desorption steam F is used for heating the activated carbon until about 5 minutes have passed from immediately after the desorption steam F was introduced into the adsorption towers 11a and 11b where the desorption step is started, the desorption occurs. The mixed gas K extruded into the upper spaces 13a and 13b, which did not proceed so much, contained only a small amount of volatile organic compounds. Even if such a mixed gas K having a low temperature and a small amount of volatile organic compounds is introduced into the combustion furnace 40, the temperature of the combustion furnace 40 will be lowered, and the operational efficiency of the processing apparatus will be lowered. Therefore, if the mixed gas K is introduced into the other adsorption towers 11a and 11b that are performing the adsorption step by utilizing the low content of the volatile organic compound, the volatile organic compound is released during standby. It can be processed without doing anything. Since the respective adsorption towers 11a and 11b are connected via the raw gas introduction pipe 22, the mixed gas extruded by opening both the raw gas inlet valves 23a and 23b provided in the raw gas introduction pipe 22. K is introduced into the other adsorption towers 11a and 11b. If three or more adsorption towers 11 are present in parallel, the raw gas inlet valve 23 is opened so that the adsorption tower 11 can be introduced into the adsorption tower 11, and neither the adsorption step nor the desorption step is performed. The raw gas inlet valve 23 of the adsorption tower 11 may be closed.

This initial desorption step ends when the amount of the volatile organic compound contained in the mixed gas K begins to increase, and is switched to discharge to the combustion furnace 40, which is a normal desorption step. The timing of this switching may be performed with the passage of a certain time, but in order to perform the switching reflecting the actual situation, it is preferable to use the measurement results of the thermometers 15a and 15b provided in the adsorbent accommodating portions 12a and 12b. The thermometers 15a and 15b are located near the upper spaces 13a and 13b, and the heating of the adsorbent gradually proceeds from the lower spaces 14a and 14b. Therefore, when the temperature of the thermometers 15a and 15b near the upper end begins to rise, most of the activated carbon contained in the adsorbent accommodating portions 12a and 12b is sufficiently heated, and the volatile organic compounds are desorbed. It is a precursor to the start. It is preferable that the temperature as a reference for specific switching is set in the range of 50 ° C. or higher and 80 ° C. or lower. It is highly possible that the activated carbon is not sufficiently heated below 50 ° C. On the other hand, when waiting until the temperature exceeds 80 ° C., full-scale desorption of volatile organic compounds begins to proceed around the thermometer, and if it is introduced into the other adsorption towers 11a and 11b, the process is wasted. It will be repeated.

The transition of opening and closing of each valve will be described with reference to the table of FIG. 2 with respect to the embodiment of the operation method of the volatile organic compound processing apparatus including the initial desorption step as described above.

In the initial state, it is assumed that all the valves connected to the suction towers 11a and 11b are closed. First, the adsorption step is started in one of the adsorption towers 11a (a101). The raw gas inlet valve 23a and the raw gas outlet valve 26a are opened. In the adsorption step (s102), the raw gas A is introduced into the upper space 13a from the raw gas inlet valve 23a, passes through the activated carbon filled in the adsorbent accommodating portion 12a, and adsorbs the contained volatile organic compounds. After the treatment in which the concentration of the volatile organic compound is reduced, the treated gas B escapes into the lower space 14a and is discharged from the raw gas outlet valve 26a. Before the amount adsorbed on the activated carbon reaches the limit, the adsorption step in the adsorption tower 11a is completed and the adsorption step in the adsorption tower 11b is started (s111). Specifically, the raw gas inlet valve 23a and the raw gas outlet valve 26a are closed, and the raw gas inlet valve 23b and the raw gas outlet valve 26b are opened. As a result, the raw gas A sent from the raw gas supply pipe 21 can be continuously adsorbed. After that, in the adsorption tower 11b, an adsorption step of passing the raw gas A introduced from the raw gas inlet valve 23b through the activated carbon of the adsorbent accommodating portion 12b to adsorb the volatile organic compounds on the activated carbon and discharging the treated gas B is performed. Continue (s111-s118).

On the other hand, in the adsorption tower 11a, the initial desorption step is started (S113). The raw gas inlet valve 23a and the steam inlet valve 33a are opened. Detachable steam F is introduced into the lower space 14a from the steam inlet valve 33a, and the activated carbon filled in the adsorbent accommodating portion 12a is gradually started to be heated from below. Along with this, the atmosphere in the upper space 13a is pushed out, and the mixed gas K combined with the cooled water vapor and the trace amount of volatile organic compounds initially desorbed escapes to the raw gas inlet valve 23a (). s114). The mixed gas K that has passed through the raw gas inlet valve 23a flows back through the raw gas introduction pipe 22 to the branch point P, and together with the raw gas A supplied from the raw gas supply pipe 21, the raw gas inlet valve of the raw gas introduction pipe 22. Heading toward the 23b side, it reaches the adsorbent accommodating portion 12b of the adsorption tower 11b in which the adsorption step is being executed, and a trace amount of the volatile organic compound contained therein is adsorbed by the activated carbon and becomes a part of the treated gas B. Is discharged. The flow of gas accompanying the supply of desorption steam F at this stage is shown by the thick arrow in FIG. However, this indicates that the gas in the upper space 13a extruded by the supply of the desorbed steam F flows into the upper space 13b of the adsorption tower 11b through the raw gas introduction pipe 22 and flows into the adsorption tower 11a. The supplied desorption steam F does not flow into the adsorption tower 11b. Before the desorption steam F reaches that level, the initial desorption step is completed and the process is switched to the original desorption step.

When the temperature of the thermometer installed near the upper center of the adsorbent accommodating portion 12a exceeds 50 degrees, the desorption of the volatile organic compounds begins to proceed in earnest, so the initial desorption step is switched to the desorption step (s115). ). The raw gas inlet valve 23a is closed and the steam outlet valve 36a is opened. After that, as a normal desorption step (s116), as the desorbed steam F is supplied, the volatile organic compounds adsorbed on the activated carbon are desorbed, and the volatile organic compounds contained in the mixed gas K increase. However, the temperature of the mixed gas K also rises. In the desorption step, the mixed gas K is discharged from the steam outlet valve 36a, sent to the combustion furnace 40, and burned together with the fuel D. When sufficient attachment / detachment is completed, the steam inlet valve 33a and the steam outlet valve 36a are closed to end the attachment / detachment step (s117).

The adsorption step is continued in the adsorption tower 11b even after the desorption in the adsorption tower 11a is completed (s118), but the adsorption step is completed before the amount of adsorption to the activated carbon reaches the limit, and the adsorption step in the adsorption tower 11a is performed. To start (s121). Specifically, the raw gas inlet valve 23b and the raw gas outlet valve 26b are closed, and the raw gas inlet valve 23a and the raw gas outlet valve 26a are opened. As a result, the raw gas A sent from the raw gas supply pipe 21 can be continuously adsorbed. After that, in the adsorption tower 11a, the adsorption step of passing the raw gas A introduced from the raw gas inlet valve 23a through the activated carbon of the adsorbent accommodating portion 12a to adsorb the volatile organic compounds on the activated carbon and discharging the treated gas B is performed. Continue (s121-s128). This is the same as the desorption step in the adsorption tower 11b in s111 to s118 described above. On the other hand, in the adsorption tower 11b, the initial desorption step is performed (s123 to s124), and then the process is switched to the desorption step (s125) to perform the desorption step (s126), similarly to the adsorption tower 11a. After the desorption step at the adsorption tower 11b is completed (s127, s128), the adsorption step at the adsorption tower 11a is completed and the process is switched to the adsorption step at the adsorption tower 11b (s131). ..

The volatile organic compound processing apparatus according to the present invention includes a timer for measuring the elapsed time from the start of each process of repeating the adsorption step and the desorption step, including the above-mentioned initial desorption step, and a thermometer 15a. , 15b, and other conditions, including the numerical values of 15b, send software commands to open and close the raw gas inlet valves 23a, 23b, raw gas outlet valves 26a, 26b, steam inlet valves 33a, 33b, and steam outlet valves 36a, 36b, respectively. By providing a control device that automatically executes the above process, the above processing may be automatically executed.

11a, 11b Adsorption tower 12a, 12b Adsorbent accommodating part 13a, 13b Upper space 14a, 14b Lower space 15a, 15b Thermometer 21 Raw gas supply pipe 22 Raw gas introduction pipe 23a, 23b Raw gas inlet valve 24 Discharge pipe 25 Exhaust pipe 26a, 26b Raw gas outlet valve 27 Exhaust blower 31 Steam supply pipe 32 Steam introduction pipe 33a, 33b Steam inlet valve 34 Steam discharge pipe 35 Combustion furnace supply pipe 36a, 36b Steam outlet valve 40 Combustion furnace 41 Combustion furnace discharge pipe 43 Steam blower A Raw gas B Processed gas C Exhaust D Fuel E Water F Detachable steam G Exhaust gas H Combustion gas I Generated steam J Boiler steam K Mixed gas P Branch point

Claims (4)

An adsorption tower that has an adsorbent accommodating part filled with an adsorbent that adsorbs volatile organic compounds, and can supply desorbed water vapor that brings the adsorbent into contact and desorbs the volatile organic compound from the adsorbent accommodating part. It is a volatile organic compound processing apparatus having a plurality of groups.
An operation is performed in which the mixed gas discharged from the start of the desorption step in one of the adsorption towers is introduced into another adsorption tower, and after the predetermined time elapses, the mixed gas is desorbed. A volatile organic compound processing device that is controlled to be introduced into a combustion furnace for producing steam for use. It has a plurality of adsorption towers having an adsorbent accommodating portion filled with activated carbon capable of adsorbing volatile organic compounds and desorbing the volatile organic compounds by receiving steam for desorption.
Each of the adsorption towers
A raw gas introduction pipe branched from a raw gas supply pipe to which the raw gas containing the volatile organic compound is supplied, and
A steam discharge pipe connected to a combustion furnace for discharging the mixed gas containing the volatile organic compound desorbed by the desorbed steam to generate the desorbed steam, and
Is connected to the upper space above the adsorbent accommodating portion.
And,
A discharge pipe that discharges the treated gas from which the concentration of the volatile organic compound has been reduced by the activated carbon from the raw gas, and
A steam introduction pipe branched from the steam supply pipe to which the detached steam is supplied, and
Is connected to the lower space below the adsorbent accommodating portion.
Valves are provided at the points where each pipe is connected.
After performing an adsorption step of reducing the concentration of volatile organic compounds in the raw gas by adsorbing it on the activated carbon,
In performing the desorption step of desorbing the volatile organic compound from the activated carbon by bringing the desorption steam into contact with the activated carbon.
The adsorption tower that starts the desorption step closes the valve of the steam discharge pipe and opens the valve of the raw gas introduction pipe for a predetermined time from the introduction of the desorption steam, and then opens the valve of the raw gas introduction pipe for the predetermined time. After that, the volatile organic compound processing apparatus is controlled to open the valve of the steam discharge pipe and close the valve of the raw gas introduction pipe. A thermometer is provided at a position of 10 cm or more and 20 cm or less from the upper end of the adsorbent accommodating portion.
The time from the introduction of the desorbed steam until the thermometer reaches a predetermined value of 50 ° C. or higher and 80 ° C. or lower is controlled as the predetermined time.
The volatile organic compound processing apparatus according to claim 1 or 2. It has a plurality of adsorption towers having an adsorbent accommodating portion filled with activated carbon capable of adsorbing volatile organic compounds and desorbing the volatile organic compounds by receiving steam for desorption.
Each of the adsorption towers
A raw gas introduction pipe branched from a raw gas supply pipe to which the raw gas containing the volatile organic compound is supplied, and
A steam discharge pipe connected to a combustion furnace for discharging the mixed gas containing the volatile organic compound desorbed by the desorbed steam to generate the desorbed steam, and
Is connected to the upper space above the adsorbent accommodating portion.
And,
A discharge pipe that discharges the treated gas from which the concentration of the volatile organic compound has been reduced by the activated carbon from the raw gas, and
A steam introduction pipe branched from the steam supply pipe to which the detached steam is supplied, and
Is connected to the lower space below the adsorbent accommodating portion.
It is an operation method of a volatile organic compound processing device in which a valve is provided at a place where each pipe is connected.
After performing an adsorption step of reducing the concentration of volatile organic compounds in the volatile organic compound-containing gas by adsorbing it on the activated carbon,
Desorption In performing the desorption step of contacting steam to desorb the volatile organic compound from the activated carbon.
The adsorption tower that starts the desorption step closes the valve of the steam discharge pipe and opens the valve of the raw gas introduction pipe for a predetermined time from the introduction of the desorption steam.
A method for operating a volatile organic compound processing apparatus, which opens the valve of the steam discharge pipe and closes the valve of the raw gas introduction pipe after the predetermined time has elapsed.

Images