JP4202369B2 - Gaseous hydrocarbon treatment and recovery equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to an apparatus and method for treating and recovering gaseous hydrocarbons contained in an atmospheric emission gas, and in particular, in a fueling facility such as a gas station, volatile combustible gasoline vapor such as gasoline is rich. those related to equipment for processing.

In the conventional method for removing gaseous hydrocarbons by adsorbent / desorbent, the gas generated from the exhaust gas source (exhaust gas containing about 40 vol% gasoline vapor) is blower or self-pressure from the exhaust gas feed pipe to the adsorption tower. The treated exhaust gas that has been fed and finished the adsorption process is air (clean gas) containing 1 vol% or less of gasoline vapor from the top of the adsorption tower (desorption tower after switching to the desorption process) through the exhaust pipe. ) Is released into the atmosphere.
In this case, the adsorption tower is operated while alternately switching the adsorption process and the desorption process described later, and this switching time (Swing Time) is set to about 5 minutes.

On the other hand, the purge gas is supplied to the adsorption tower after the adsorption step through the purge gas supply pipe, and desorption is performed by suction with a vacuum pump. A part of the clean gas discharged from the top of the adsorption tower during the adsorption operation is used as the purge gas, and the vacuum pump is operated at about 25 Torr.
The purged exhaust gas containing gasoline vapor after desorption is supplied to a gasoline recovery device through an air supply pipe and is brought into contact with liquid gasoline through a distribution pipe to recover the gasoline vapor in the purge exhaust gas as a liquid (gasoline absorption liquid).

A slight amount of gasoline vapor remains in the exhaust gas from the gasoline collector, so it is returned to the exhaust gas pipe again through the return pipe, and adsorbed with the exhaust gas from the exhaust gas generation source. In order to cool the adsorbent layer in the adsorption tower, cooling water is circulated through the inner cylinder.
With this configuration, almost all of the gasoline vapor can be recovered as liquid gasoline, and the concentration of the gasoline vapor discharged from the adsorption tower is sufficiently low so that it does not cause air pollution (for example, patents) Reference 1).

Japanese Patent No. 2766793 (page 3-6, FIG. 1)

In the recovery method in which gasoline vapor is desorbed by the vacuum pump of Patent Document 1, the motive energy of the pump becomes extremely large, which is not realistic.
In addition, in order to perform a large amount of exhaust gas adsorption treatment, it is necessary to enlarge the adsorption tower or shorten the adsorption / desorption switching time (Swing Time). However, the problem of the installation area and the problem of the cost of the adsorbent remain. In addition, if the switching time is shortened, there are problems that the adsorbed gasoline vapor cannot be sufficiently desorbed and the life of the valve and the like is shortened.
Furthermore, when the adsorption tower is enlarged and a large amount of adsorbent is used, there is a problem that the pressure loss of the adsorption tower increases, the processing gas flow rate becomes slow, and the treatment cannot be performed efficiently.

Further, although the gasoline vapor always contains moisture in the air, the conventional method has a problem that the adsorption performance of the adsorbent is lowered because this moisture is also adsorbed simultaneously with the gasoline vapor.
Moreover, when using for the recovery of the gasoline vapor which leaks from the underground storage tank of a gas station, it is necessary to cope with the gasoline vapor generated in large quantities in the time zone for refueling the underground tank. For this reason, it is necessary to design the apparatus capacity in accordance with the peak, and it is necessary to enlarge the apparatus more than necessary.

The present invention has been made to solve the above-described problems, and prevents the adsorbent from being poisoned by the influence of moisture contained in the gasoline vapor. it is intended to provide a recovery equipment.

The apparatus for treating and recovering gaseous hydrocarbons according to the present invention is an apparatus for recovering gasoline vapor that leaks during refueling from a gasoline storage facility, and a first condensing device that removes moisture and gasoline vapor contained in the gasoline vapor, A second condenser for removing gasoline vapor provided downstream of the first condenser, and a first adsorption / desorption device provided downstream of the second condenser; and the first adsorption A suction pump for taking out gasoline vapor from the desorption device, a pressure pump for pressurizing the gasoline vapor taken out by the suction pump, a third condenser for removing pressurized gasoline vapor, and the third condenser can be recovered. And a second adsorption / desorption tower for collecting the gasoline vapor that was not present.

The present invention relates to a first condensing device that removes moisture and gasoline vapor, a second condensing device that removes gasoline vapor, a first adsorption / desorption device provided downstream of the second condenser, and a gasoline vapor Exhaust gas can be made extremely clean (gasoline concentration of 1 Vol% or less) by arranging a third condenser that removes the gas and a second adsorption / desorption tower that collects gasoline vapor that could not be recovered by the third condenser. Moreover, a small and inexpensive gasoline vapor recovery device can be realized. In particular, even when gasoline vapor contains moisture, the adsorbent is not likely to be poisoned by moisture, and it does not freeze in the piping of the first condenser or adsorption / desorption tower. Driving operation can be realized.
In addition, by creating two temperature zones and separating the role of water and gasoline recovery, wasteful energy consumption due to freezing of water can be reduced, realizing an energy-saving gasoline vapor recovery device. it can. In addition, the first condenser and the adsorption / desorption tower perform indirect cooling, and the second condenser performs direct cooling. In addition to the on / off operation of the refrigerator, the refrigerant flow is controlled to condense. The operation of the apparatus can be controlled, and an energy-saving gasoline vapor recovery apparatus can be realized. In addition, since the second condenser is installed to efficiently recover the gasoline vapor and then the gasoline vapor is supplied to the first adsorption / desorption tower, the gasoline vapor can be adsorbed with a very small amount of adsorbent, The amount of adsorbent used can be greatly reduced.
Furthermore, after the gasoline adsorption operation is completed, the performance of the desorption-related equipment attached to the first adsorption / desorption tower is reduced by performing a recovery operation of the gasoline stored in the first adsorption / desorption tower over time. Therefore, an inexpensive gasoline vapor recovery device can be realized.

Embodiment 1.
FIG. 1 is an overall configuration diagram showing a flow of a gaseous hydrocarbon treatment / recovery device according to Embodiment 1 of the present invention.

  In FIG. 1, 1 is a gasoline storage tank for storing gasoline, 2 is an oil supply pipe used when gasoline is supplied to the gasoline storage tank 1 from a tank truck or the like, 3a, 3b, and 3c are for switching the flow direction of gasoline vapor-containing air. Three-way switching valve 4 is a pressure regulating valve provided in a passage through which gasoline vapor is discharged to the atmosphere by the three-way switching valve 3a, 5 is a refrigerator, 6 is connected to the refrigerator 5, and a temperature medium (brine liquid or the like) is supplied. A heat exchanger to be cooled, 7 is a temperature medium tank containing the temperature medium cooled by the heat exchanger 6, 8 is a liquid circulation pump for sending the cooled temperature medium from the temperature medium tank 7, and 9 is a liquid circulation pump 8. The first condensing device cooled by the sent temperature medium, 10 is the second condensing device cooled by the refrigerator 5, and 11 is sent by the liquid circulation pump 8. The first adsorption / desorption tower cooled by the temperature medium, 12a and 12b are two-way valves through which the air from which the gasoline vapor discharged from the first adsorption / desorption tower 11 and the second adsorption / desorption tower 16 has been removed passes, and 13 is the first A suction pump for taking out the gasoline adsorbed by the adsorption / desorption tower 12 as gasoline vapor from the first adsorption / desorption tower 12, 14 is a pressure pump for compressing and compressing the gasoline vapor-containing air taken out by the suction pump 13, and 15 is pressure A third condensing device for liquefying and recovering gasoline from gasoline vapor-containing air compressed and compressed by the pump 14, and a second adsorption / desorption tower 16 for adsorbing and recovering gasoline from the gasoline vapor-containing air discharged from the third condensing device 15. 17a and 17b are flow control valves provided in the first adsorption / desorption tower 11 and the second adsorption / desorption tower 16, and 18 is a gasoline storage tank for liquefied gasoline. Gasoline pipe for returning to, 19 is a pressure controller for regulating the pressure of the third condenser 15 and in the second desorption column 16. The first condensing device 9, the second condensing device 10, and the first adsorption / desorption tower 11 are sequentially arranged from the upstream side (front stage) to the downstream side (rear stage) in the flow direction of the gasoline vapor, and in the installation position. Are stacked from the bottom to the top.

  Next, the operation of the gaseous hydrocarbon treatment / recovery device of FIG. 1 will be described. The operation of the apparatus shown in the present embodiment is usually performed in three steps: an adsorption process, a first regeneration process, and a second regeneration process. First, the adsorption process will be described. Normally, the three-way switching valve 3a is connected to the atmosphere discharge side, and the pressure of the gasoline storage tank 1 is controlled by the pressure regulating valve 4, so that the pressure of the gasoline storage tank 1 does not become higher than a predetermined pressure.

  When gasoline refueling is started, the three-way switching valve 3a is switched to the collecting device side and the two-way valve 12a is opened. When the three-way switching valve 3a is switched and refueling to the gasoline storage tank 1 is started from a tank truck or the like via the gasoline refueling pipe 2, the gasoline vapor filled in the gasoline storage tank 1 is discharged from the gasoline storage tank 1. Discharged. The gasoline concentration of the gasoline vapor at this time is about 30 to 40 vol% at normal temperature. Gasoline vapor discharged from the gasoline storage tank 1 is sent to the first condenser 9 via the three-way switching valve 3a. The first condensing device 9 is indirectly cooled by the temperature medium cooled by the refrigerator 5 being supplied by the liquid circulation pump 8. Usually, the inside of the first condensing device 9 is maintained at about 0 ° C. to 5 ° C., and a portion of gasoline vapor and moisture contained in the gas condense and are condensed by a gas-liquid separator (not shown) or the like. It is separated into gas (gasoline vapor) and liquid (gasoline). The liquid accumulates below the first condenser 9 and is returned to the gasoline storage tank 1 via the gasoline pipe 18. In FIG. 1, gasoline vapor is circulated from the lower side of the first condensing device 9, but liquefied gasoline is introduced by introducing gasoline vapor from the upper side of the first condensing device 9 to circulate downward. And moisture is efficiently flowed downward by gravity and gas flow, and recovery of these liquefied materials becomes easy.

  By the way, under the conditions of the pressure of 0.1 MPa and the cooling temperature of 5 ° C., which are the operating conditions of the first condenser 9, the gasoline vapor concentration is about 20 vol%. When the saturated concentration of gasoline vapor was examined, the saturated gasoline vapor concentration was about 20 vol% at a pressure of 0.1 MPa and a temperature of 5 ° C. Under these conditions, the gasoline vapor concentration would not theoretically be less than 20 vol%. . Further, the gasoline vapor concentration at the outlet of the first condenser 9 can be reduced by lowering the temperature. However, when the set temperature is below the freezing point, water contained in the gas is frozen in the first condenser 9 and the pressure loss inside the first condenser 9 is increased, so the set temperature of the first condenser 9 is It is desirable to set the temperature to about 0 to 5 ° C.

  Subsequently, about 20 vol% of gasoline vapor that could not be processed by the first condenser 9 is supplied to the second condenser 10. The second condenser 10 is directly cooled by supplying the refrigerant cooled by the refrigerator 5 to the second condenser 10. Usually, the inside of the second condensing device 10 is kept at about −20 ° C. to −10 ° C., and a part of gasoline vapor is condensed and separated into gas (gasoline vapor) and liquid (gasoline). The liquid accumulates below the first condenser 9 and is returned to the gasoline storage tank 1 via the gasoline pipe 18. The inside of the second condensing device 10 is cooled to below the freezing point, but since most of the water is removed by the first condensing device 9, the water that forms ice in the second condensing device 10 is very little. . In addition, in FIG. 1, the gasoline vapor is circulated from the lower side of the second condensing device 10, but as in the case of the first condensing device 9, the gasoline vapor is introduced from above the second condensing device 10. By flowing downward, liquefied gasoline and moisture are efficiently flowed downward by gravity and gas flow, and recovery of these liquefied substances becomes easy.

  By the way, under the conditions of the pressure of 0.1 MPa and the cooling temperature of −10 ° C., which are the operating conditions of the second condenser 10, the gasoline vapor concentration is about 8 vol%. When the saturated concentration of gasoline vapor was examined, the saturated gasoline vapor concentration was about 8 vol% at a pressure of 0.1 MPa and a temperature of −10 ° C. Under these conditions, the gasoline vapor concentration would theoretically be 8 vol% or less. Absent. In addition, the gasoline vapor concentration at the outlet of the second condenser 10 can be reduced by lowering the temperature. However, it was found that even when cooled to −30 ° C., the gasoline vapor concentration was about 5 vol%, and even when cooled to −30 ° C. or lower, the gasoline vapor concentration hardly decreased. Since energy used for cooling to −30 ° C. or lower increases, efficient energy utilization cannot be performed. Therefore, it is desirable that the set temperature of the second condenser 10 is −30 ° C. or higher.

  Subsequently, about 8 vol% of gasoline vapor that could not be processed by the second condenser 10 is sent to the first adsorption / desorption tower 11 and processed. FIG. 1 shows a case where the first adsorption / desorption tower 11 is operating as an adsorption tower. Accordingly, the two-way valve 12a is open (black), and the flow rate control valve 17a (white) is closed. After adsorption treatment for an arbitrary time as an adsorption tower, it is used as a desorption tower. In this case, the two-way valve 12a is used in a closed state and the flow rate adjusting valve 17a is used in an open state.

  An adsorbent that adsorbs gasoline vapor is sealed in the first adsorption / desorption tower 11. Silica gel was used as an adsorbent for gasoline vapor. In particular, silica gel or synthetic zeolite having a pore diameter of 4 to 100 angstroms or a mixture thereof is effective. By passing gasoline vapor through the adsorbent, the gasoline component is adsorbed and removed, and becomes clean air having a gasoline concentration of 1 vol% or less and released to the atmosphere through the two-way valve 12a.

The first adsorption / desorption tower 11 is always cooled to a constant temperature by the temperature medium supplied by the liquid circulation pump 8 regardless of the role of gasoline vapor adsorption / desorption. In other words, the cooling system of the first condenser 9 and the first adsorption / desorption tower 11 is always controlled to be maintained at a set temperature of 0 to 5 ° C. This is because the silica gel packed in the first adsorption / desorption tower 11 is cooled by heat transfer from a heat exchanger (not shown) such as a finned tube heat exchanger, so that a certain amount of cooling time is indispensable. This is because it cannot cope with instantaneous driving. Furthermore, the provision of the refrigerator 5 having a large cooling capacity so that it can be cooled in a short time adversely affects the facility cost and makes it impossible to provide an inexpensive gasoline recovery device. In addition, by lowering the temperature inside the first adsorption / desorption tower 11, the adsorption capacity can be increased and the amount of silica gel used can be reduced. However, when the internal temperature of the first adsorption / desorption tower 11 is below the freezing point, water is frozen in the first adsorption / desorption tower 11, so that ice gradually accumulates in the adsorbent such as silica gel, and the adsorbent gasoline. There arises a problem that the adsorption capacity is lowered. Therefore, the internal temperature of the first adsorption / desorption tower 11 is preferably set to a freezing point or higher.
From the above, by having two cooling systems with different temperature zones, the cooling system of the first condenser 9 and the first adsorption / desorption tower 11 and the cooling system of the second condenser 10, efficient gasoline recovery can be achieved. It can be carried out.

  Since the first adsorption / desorption tower 11 adsorbs gas at atmospheric pressure, the external structure of the first adsorption / desorption tower 11 is not limited, but the pressure inside the adsorption tower is about 0.02 MPa at the time of desorption. It has a cylindrical structure. By adopting such a structure, the pressure applied to the wall surface can be made uniform, and even when the pressure in the first adsorption / desorption tower 11 becomes about 0.02 MPa, the safety is high, that is, the shape is deformed. An adsorption / desorption tower 11 that does not occur can be realized. In addition, the internal structure of the first adsorption / desorption tower 11 is provided with a fin tube heat exchanger (a temperature medium is passed through the heat transfer tube with aluminum fins) in consideration of heat transfer to silica gel or synthetic zeolite, and between the aluminum fins. At the same time as silica gel or synthetic zeolite is packed in, silica gel outflow prevention nets are provided at the top and bottom to prevent the silica gel from flowing out into the pipe and improve the gas flow. In this case, in order to make the adsorption of the gasoline vapor on the silica gel uniform, a current plate made of punching metal or the like may be installed so that the gasoline vapor flows uniformly in the first adsorption / desorption tower 11. . The direction of the fins of the fin tube heat exchanger is desirably set so as to be parallel to the flow direction of the gasoline vapor so as not to cause pressure loss when the gasoline vapor flows. Further, in order to efficiently cool the silica gel filled in the vicinity of the outer wall, it is necessary to prevent a gap between the fin tube heat exchanger and the outer wall.

  In this case, a grid-like or plate-like metal that contacts the vent part is provided on the side with the vent (aluminum or copper is optimal for excellent heat transfer characteristics), and fin tube heat exchange is provided on the side without the vent. It is effective to eliminate the gap between the outer wall and the finned-tube heat exchanger by increasing the length of the fins themselves. Further, a metal rod, a pipe with fins, or the like may be inserted so as to eliminate a gap portion between the outer wall and the fin tube heat exchanger. In addition, when flowing the temperature medium through the heat transfer tube of the finned tube heat exchanger, branch the piping through which the temperature medium flows before entering the heat transfer tube, and divide the finned tube heat exchanger into a plurality of blocks. It is better to make it flow. Thereby, the pressure loss of the piping through which the temperature medium flows can be reduced, and the capacity of the liquid circulation pump 8 that supplies the temperature medium to the first adsorption / desorption tower 11 can be reduced.

  Further, in this case, since gasoline vapor flows from the bottom to the top, it is desirable to arrange the finned tube heat exchanger and the lower silica gel outflow prevention net in contact with each other. As a result, a space between the silica gel outflow prevention net and the fin tube heat exchanger, that is, a space filled only with silica gel can be eliminated, and the silica gel can be sufficiently cooled during adsorption. As a result, it is possible to prevent the temperature of the silica gel existing in the portion where the gasoline vapor having the highest gasoline concentration enters and to provide a safe first adsorption / desorption column 11. In addition, when gasoline vapor | steam flows from the top to the bottom, it cannot be overemphasized that an upper silica gel outflow prevention net | network and a finned tube heat exchanger are contacted.

When the first condenser 9 and the second condenser 10 are not provided upstream of the first adsorption / desorption tower 11, high-concentration gasoline vapor flows into the first adsorption / desorption tower 11 and is contained in the gasoline vapor. Moisture is adsorbed by the adsorbent, resulting in a decrease in gasoline vapor adsorption performance, and an excessive amount of adsorbent is required. Further, when the temperature of the first adsorption / desorption tower 11 is lowered below the freezing point, there may be a serious trouble such as moisture condensing on the adsorbent surface and clogging of gas.
In this embodiment, since the first condensing device 9 and the second condensing device 10 are provided in the first stage of the first adsorption / desorption tower 11, moisture is removed together with gasoline vapor. It is possible to prevent the adverse effects of. In addition, since the amount of gasoline processed in the first adsorption / desorption tower 11 can be greatly reduced, the first adsorption / desorption tower 11 can be made small and inexpensive. Furthermore, in the present embodiment, the high concentration (40 vol%) gasoline discharged from the gasoline storage tank 1 can be reduced to 20 vol% by the first condenser 9 and can be reduced to 8 vol% by the second condenser 10. The amount of gasoline processed in the adsorption / desorption tower 11 can be reduced to 20% (= 8% / 40%) with respect to the total suction amount. That is, by providing the first condensing device and the second condensing device 6 in the previous stage of the first adsorption / desorption tower 11, the volume of the first adsorption / desorption tower 11 can be reduced to approximately 1/5.

  Next, the effect of the cooling temperature of the second condenser 10 on the silica gel filling amount of the first adsorption / desorption tower 11 will be described. FIG. 2 shows the relationship between the cooling temperature inside the second condenser 10 and the silica gel filling amount required when the gasoline vapor concentration is 1 vol% or less at the outlet of the first adsorption / desorption tower 11. In addition, the amount of silica gel reduction is shown on the basis of the amount of silica gel required when the cooling temperature of the second condenser 10 is 5 ° C. Thus, by lowering the cooling temperature of the second condenser 10, the amount of silica gel packed in the first adsorption / desorption tower 11 can be reduced. However, it was found that the amount of silica gel hardly decreased even when cooled to −30 ° C. or lower. As a result of experiments conducted on various types of gasoline, it was found that the saturated concentration of gasoline vapor hardly decreased even when the cooling temperature was -30 ° C or lower, regardless of the composition of gasoline vapor. This is thought to be affecting the decline in Therefore, considering the input energy, it is not efficient to set the cooling temperature of the second condenser 10 to −30 ° C. or lower, and it is desirable to set the cooling temperature of the second condenser 10 to −30 ° C. or higher.

  Next, the regeneration process of the first adsorption / desorption tower 11, that is, the desorption process of gasoline vapor will be described. The regeneration process of the first adsorption / desorption tower 11 includes a first regeneration process in which gasoline is desorbed from the first adsorption / desorption tower 11 and discharged to the atmosphere via the third condenser 15 and the second adsorption / desorption tower 16; There are two steps of a second regeneration step in which gasoline is desorbed from the second adsorption / desorption tower 16 and discharged to the atmosphere via the first condenser 9, the second condenser 10 and the first adsorption / desorption tower 11. First, the first regeneration process will be described.

  When desorbing gasoline adsorbed on the adsorbent, the suction pump 13 sucks gas from the first adsorption / desorption tower 11 via the three-way switching valve 3b to desorb the gasoline from the adsorbent. At this time, the two-way valve 12a is closed. When the pressure in the first adsorption / desorption tower 11 is reduced to a predetermined pressure, the flow control valve 17a is opened so that a constant flow of air flows from the atmosphere into the first adsorption / desorption tower 11, and the first adsorption / desorption tower 11 is opened. Make the internal pressure almost constant. The first adsorption / desorption tower 11 operates at an atmospheric pressure of 0.1 MPa at the time of adsorption, but is depressurized below the atmospheric pressure by the suction pump 13 at the time of desorption, so that the gasoline adsorbed on the adsorbent is high due to this pressure difference. Desorbed in a concentrated state. In this case, depending on the gas flow rate of gasoline vapor and the amount of adsorption during adsorption, the gasoline vapor concentration is 20 to 40 vol% by controlling the pressure in the first adsorption / desorption tower 11 to 0.02 to 0.04 MPa. Can be.

  The desorbed gasoline vapor is guided to the pressurizing pump 14 through the three-way switching valve 3c. The gasoline vapor is pressurized to about 0.3 MPa by the pressurizing pump 14 and supplied to the third condensing device 15. That is, the third condensing device 15 is supplied with a high concentration / pressurized gasoline vapor having a gasoline concentration of 30 vol% and a pressure of 0.3 MPa. The third condenser 15 is indirectly cooled by supplying the temperature medium cooled by the refrigerator 5 by the liquid circulation pump 8. Normally, the interior of the third condenser 15 is maintained at about 0 ° C. to 5 ° C., and a portion of gasoline vapor and moisture contained in the gas are condensed and gas is condensed by a gas-liquid separator (not shown) or the like. (Gasoline vapor) and liquid (gasoline). The liquid accumulates below the third condenser 15 and is returned to the gasoline storage tank 1 via the gasoline pipe 18. In addition, as shown in FIG. 1, by introducing gasoline vapor from above the third condenser 15 and circulating it downward, liquefied gasoline and moisture are efficiently flowed downward by gravity and gas flow. Recovery of the liquefied product becomes easier.

  By the way, under the conditions of the pressure of 0.3 MPa and the cooling temperature of 5 ° C., which are the operating conditions of the third condenser 15, the concentration of the gasoline vapor at the outlet is about 8 vol%. As can be seen from the saturated concentration diagram of gasoline vapor, the saturated gasoline vapor concentration is about 8 vol% at a pressure of 0.3 MPa and a temperature of 5 ° C. Under these conditions, the gasoline vapor concentration should theoretically be 8 vol% or less. There is no. Moreover, the gasoline vapor concentration at the outlet of the third condenser 15 can be reduced by lowering the temperature. However, if the set temperature is below the freezing point, the water contained in the gas is frozen in the third condenser 15 and increases the pressure loss inside the third condenser 15, so the set temperature of the third condenser 15 is It is desirable to set the temperature to about 0 to 5 ° C. Moreover, in the 3rd condenser 15, since it pressurizes to about 0.3 MPa, it is set as the cylindrical structure. By adopting such a structure, the pressure applied to the wall surface can be made uniform, and even when the pressure in the third condenser 15 becomes about 0.3 MPa, the safety is high, that is, the shape is deformed. A third condensing device 15 can be realized.

  Subsequently, about 8 vol% of gasoline vapor that could not be processed by the third condenser 15 is sent to the second adsorption / desorption tower 16 and processed. FIG. 1 shows a case where the second adsorption / desorption tower 16 operates as an adsorption tower. Accordingly, the two-way valve 12b is open (black), and the flow rate control valve 17b (white) is closed. After adsorption treatment for an arbitrary time as an adsorption tower, it is used as a desorption tower. In this case, the two-way valve 12b is closed and the flow rate control valve 17b is opened.

  The second adsorption / desorption tower 16 is also filled with an adsorbent that adsorbs gasoline vapor, and is the same as the first adsorption / desorption tower 11. By passing gasoline vapor through the adsorbent, the gasoline component is adsorbed and removed, and becomes clean air having a gasoline concentration of 1 vol% or less and is released to the atmosphere through the two-way valve 12b. The second adsorption / desorption tower 16 is also always cooled to a constant temperature by the temperature medium supplied by the liquid circulation pump 8 regardless of the role of gasoline vapor adsorption / desorption. That is, like the first adsorption / desorption tower 11, the operation is always controlled so as to be maintained at 0 to 5 ° C. The second adsorption / desorption tower 16 adsorbs a gas having a pressure of about 0.3 MPa, and the pressure inside the adsorption tower is about 0.02 MPa at the time of desorption. For this reason, a cylindrical structure is adopted. By adopting such a structure, the pressure applied to the wall surface can be made uniform, and even if the pressure in the second adsorption / desorption tower 16 is swung from about 0.03 to 0.3 MPa, safety is ensured. The second adsorption / desorption tower 16 which is high, that is, does not undergo shape deformation can be realized. Furthermore, the internal structure is desirably the same as that of the first adsorption / desorption tower 11.

  Thus, in the first regeneration step, the gasoline vapor discharged from the first adsorption / desorption tower 11 can be efficiently liquefied and recovered by being cooled and adsorbed in a pressurized state. At the time of desorption, the desorption speed can be increased or the gasoline vapor concentration can be increased by increasing the temperature inside the first adsorption / desorption tower 11, but the energy consumption increases by swinging the temperature. For this reason, it is energetically effective to perform desorption at the same temperature as during adsorption without increasing the temperature during desorption.

  Next, a second regeneration step in which gasoline is desorbed from the second adsorption / desorption tower 16 and discharged to the atmosphere via the first condenser 9, the second condenser 10, and the first adsorption / desorption tower 11 will be described. When the gasoline adsorbed on the adsorbent in the second adsorption / desorption tower 16 is desorbed, the gas is sucked from the second adsorption / desorption tower 16 by the suction pump 13 via the three-way switching valve 3b to desorb the gasoline from the adsorbent. To do. At this time, the two-way valve 12b is closed. Further, when the pressure in the second adsorption / desorption tower 16 is lowered to a predetermined pressure, the flow control valve 17b is opened so that a constant flow of air flows from the atmosphere into the second adsorption / desorption tower 16, and the second adsorption / desorption tower 16 Make the internal pressure almost constant. The second adsorption / desorption tower 16 operates at an atmospheric pressure of 0.3 MPa at the time of adsorption, but is depressurized below the atmospheric pressure by the suction pump 13 at the time of desorption, so that the gasoline adsorbed on the adsorbent is high due to this pressure difference. Desorbed in a concentrated state. In this case, depending on the gas flow rate of gasoline vapor and the amount of adsorption at the time of adsorption, by controlling the pressure in the second adsorption / desorption tower 16 to 0.02 to 0.04 MPa, the gasoline vapor concentration is 20 to 40 vol%. Can be.

  The desorbed gasoline vapor is guided to the first condenser 9 through the three-way switching valve 3c. That is, high-concentration gasoline vapor having a gasoline concentration of 30 vol% and a pressure of 0.1 MPa is supplied to the first condenser 9. As described above, the inside of the first condensing device 9 is maintained at about 0 ° C. to 5 ° C., and a portion of gasoline vapor and moisture contained in the gas are condensed to form a gas-liquid separator (not shown). ) Etc. to separate gas (gasoline vapor) and liquid (gasoline). Subsequently, about 20 vol% of gasoline vapor that could not be processed by the first condenser 9 is supplied by the second condenser 10 as in the case of adsorption. Here, only about 8 vol% of gasoline vapor which has been further liquefied and recovered and could not be processed by the second condensing device 10 is sent to the first adsorption / desorption tower 11. In the first adsorption / desorption tower 11, gasoline components pass through the adsorbent, so that the gasoline components are adsorbed and removed and become clean air having a gasoline concentration of 1 vol% or less and released to the atmosphere via the two-way valve 12 a. .

  As described above, the series of operations is completed by performing the adsorption process, the first regeneration process, and the second regeneration process. Normally, every time there is refueling in the gasoline storage tank 1, these series of operations are repeated. By this operation, it is a gaseous hydrocarbon treatment / recovery device that can only discharge 1 vol% of gasoline vapor to the atmosphere at the maximum and has a very low environmental load. Moreover, since only 1 vol% of gasoline vapor is discharged at the maximum, 39 vol% of 40 vol% of gasoline vapor can be recovered, and the recovery efficiency is 97.5%, which is a very high efficiency recovery device. In addition, since the adsorption operation is performed after the condensation operation is performed in two temperature zones, the first adsorption / desorption tower 11 can be greatly reduced in size and the entire apparatus can be reduced in size.

  The exhaust port for gasoline vapor from the first adsorption / desorption tower 11 and the second adsorption / desorption tower 16 during desorption is a supply port for gasoline vapor to the first adsorption / desorption tower 11 and the second adsorption / desorption tower 16 during adsorption. Are provided in the same part. Since the adsorption / desorption towers 11 and 16 are operated so that the gasoline vapor concentration at the outlets of the adsorption / desorption towers 11 and 16 is 1 vol% or less, the adsorption / desorption towers 11 and 16 have a high density in the vicinity of the gasoline vapor inlets at the time of adsorption. Gasoline vapor is adsorbed in the vicinity of the gasoline vapor outlets of the adsorption / desorption towers 11 and 16 so that the gasoline vapor is not so adsorbed. In order to efficiently recover the gasoline vapor discharged from the adsorption / desorption towers 11 and 16 at the time of desorption, it is necessary to make the gasoline vapor concentration as high as possible. Therefore, since it is possible to discharge high-concentration gasoline vapor by discharging gasoline vapor from the portion adsorbed at high density, the portion adsorbed at high density, that is, adsorption / desorption towers 11 and 16 adsorbs. It is better to suck and discharge gasoline vapor at the time of desorption from the vicinity of the gasoline vapor intake port at the time.

  Since only the desorption method using the pressure difference by the suction pump 13 is not very efficient, it is effective to introduce the purge gas from the outside. In this embodiment, by combining the suction and the gas replacement by the purge gas, Gasoline vapor is desorbed from the adsorption / desorption towers 11 and 16. In the present embodiment, the purge gas sent to the adsorption / desorption towers 11 and 16 is air in the atmosphere. Since air contains a certain amount of moisture, it is necessary to reduce the supply of purge gas to the adsorption / desorption towers 11 and 16 as much as possible. Therefore, as described above, when a certain amount of time elapses during desorption, when the pressure in the adsorption / desorption towers 11 and 16 decreases to a predetermined pressure, the flow control valves 17a and 17b open, and a constant flow of air is absorbed and desorbed from the atmosphere. By flowing into the towers 11 and 16, desorption is performed so that the pressure inside the adsorption / desorption towers 11 and 16 is made substantially constant. FIG. 3 is a diagram for explaining a control method of the purge gas amount. By doing in this way, it can prevent that the amount of suction gas falls with time passage, and can perform desorption operation of gasoline vapor stably.

  As for the timing of introducing purge gas, a purge gas is introduced after a fixed time has passed from desorption using a timer (timer method), and purge gas is introduced when the internal pressure of the adsorption / desorption towers 11 and 16 reaches a set value. A method (pressure measurement method) and a method (gas amount measurement method) in which purge gas is introduced when the amount of gasoline vapor discharged from the adsorption / desorption towers 11 and 16 reaches a set value can be considered. The timer method is most advantageous in terms of initial cost, but the timing at which purge gas is introduced may be shifted depending on the amount of gasoline adsorbed to the adsorption / desorption towers 11 and 16, and the effectiveness of introducing purge gas may be reduced. is there. That is, if the adsorption amount is large, purge gas is introduced when there is sufficient gasoline vapor in the adsorption / desorption towers 11, 16, and the concentration of gasoline vapor discharged from the adsorption / desorption towers 11, 16 decreases. Conversely, when the adsorption amount is small, the time period during which the amount of gasoline vapor gas discharged from the adsorption / desorption towers 11 and 16 is small increases, and the gasoline vapor cannot be efficiently discharged from the adsorption / desorption towers 11 and 16. The pressure measurement method and the gas amount measurement method can solve the problems of the timer method described above, and can realize efficient desorption. In this gasoline recovery device, for safety, it is essential to attach a pressure gauge to the piping system through which gasoline vapor flows. Therefore, since the pressure measurement method can be used with those pressure gauges, it is considered to be most effective among the three methods.

  Refueling a gasoline storage tank at a gas station is usually performed regularly for a certain period of time. For this reason, the generation of gasoline vapor is limited to a certain time of the day. Therefore, from the viewpoint of increasing the operating rate of the apparatus, the adsorption operation is performed during the time period when the gasoline vapor is generated, and the adsorption / desorption towers 11 and 16 are regenerated during the time period when the gasoline vapor is not generated. Is considered effective. Next, the effectiveness of gasoline recovery by reducing the amount of gas and operating for a long time will be described with reference to FIG. Thus, it has been found that the recovery rate decreases by reducing the gas flow rate. Further, it has been clarified that the recovery rate does not increase when the gas flow rate is 40 L / min or more. This is because as the gas flow rate increases, the amount of air flowing in from the flow rate control valve 17a increases, so that the gasoline vapor concentration is diluted by the air and the amount of gasoline condensing in the third condenser 15 decreases. is there. Therefore, it was found that when gasoline vapor is desorbed from the first adsorption / desorption tower 11, the gas flow rate is preferably at most 40 L / min. From the above, it is possible to recover the first adsorption / desorption tower 11 with high efficiency by regenerating the first adsorption / desorption tower 11 over a long period of time at a low flow rate.

  Next, a control method of the gaseous hydrocarbon treatment / recovery device will be described. When the recovery device is stopped, the suction pump 13 and the pressure pump 14 are stopped, the two-way valves 12a and 12b are fully closed, and the flow rate control valves 17a and 17b are closed. The first adsorption / desorption tower 11 and the second adsorption / desorption tower 16 are cooled by the temperature medium cooled by the refrigerator 5. When refueling is started in the gasoline storage tank 1, the three-way switching valve 3a is switched, the two-way valve 12a is opened, and the cooling of the second condensing device 10 is started. When the temperature inside the second condenser 10 reaches a set value, recovery of gasoline vapor is started. When the fuel supply to the gasoline storage tank 1 and the generation of gasoline vapor are completed, the three-way switching valve 3a is switched, the two-way valve 12a is closed, and the cooling of the second condenser 10 is stopped. Thereafter, when the two-way valve 12b is opened and the suction pump 13 and the pressure pump 14 are operated, the gasoline vapor is desorbed from the first adsorption / desorption tower 11 and passes through the third condenser 15 and the second adsorption / desorption tower 16. To the atmosphere. At this time, when the pressure in the first adsorption / desorption tower 11 decreases to a predetermined concentration due to the operation of the suction pump 13, the flow adjustment valve 17 a starts to open, and the flow adjustment valve so that the predetermined flow flows through the first adsorption / desorption tower 11. The opening degree of 17a is controlled. When the first regeneration process is completed by a timer or the like, the suction pump 13 and the pressure pump 14 are stopped, the flow rate adjustment valve 17a is closed, and the two-way valve 12b is closed. Thereafter, cooling of the second condenser 10 is started, and when the temperature inside the second condenser 10 reaches a set value, regeneration of the second adsorption / desorption tower 16 is started. When the two-way valve 12a is opened and the suction pump 13 and the pressure pump 14 are operated, gasoline vapor is desorbed from the second adsorption / desorption tower 16, and the first condenser 9, the second condenser 10, and the first adsorption / desorption tower. It passes in order of 11 and is discharged into the atmosphere. At this time, when the pressure in the second adsorption / desorption tower 16 decreases to a predetermined concentration due to the operation of the suction pump 13, the flow adjustment valve 17 b starts to open, and the flow adjustment valve so that the predetermined flow flows through the second adsorption / desorption tower 16. The opening degree of 17b is controlled. When the regeneration process is completed for a certain time, the cooling of the second condenser 10 is stopped, the suction pump 13 and the pressurizing pump 14 are stopped, the two-way valves 12a and 12b are fully closed, and the flow rate adjusting valve 17a, 17b is in a closed state. In this way, the operation of the recovery device is repeated.

Finally, the effect of increasing the internal pressure of the third condenser 15 and the second adsorption / desorption tower 16 using the pressure pump 14 and the pressure controller 19 will be described. FIG. 5 shows the relationship between the internal pressure of the third condenser 15 and the second adsorption / desorption tower 16 and the weight of the adsorbent filled in the second adsorption / desorption tower 16. Thus, it became clear that the filling amount of silica gel can be reduced by increasing the internal pressure. However, it was found that the silica gel filling amount was hardly reduced even at 0.4 MPa or more. On the other hand, when the pressure is increased, the pressure resistance of the third condensing device 15 and the second adsorption / desorption tower 16 needs to be increased. Therefore, it was confirmed that the internal pressure of the third condenser 15 and the second adsorption / desorption tower 16 was effectively 0.2 to 0.3 MPa. FIG. 6 is an overall configuration diagram showing a flow of a gaseous hydrocarbon treatment / recovery device that does not include the pressurizing pump 14 and the pressure controller 19. Thereby, the number of parts which comprise an apparatus can be reduced. However, since the amount of silica gel used in the second adsorption / desorption tower 16 is more than doubled, it was found that the second adsorption / desorption tower 16 becomes large and the apparatus cost does not decrease so much.
From the above, the pressurizing pump 14 and the pressure controller 19 are provided to increase the internal pressure of the third condenser 15 and the second adsorption / desorption tower 16 to 0.4 MPa, preferably 0.2 to 0.3 MPa. By increasing the height, it is possible to provide an inexpensive recovery device.

Embodiment 2.
FIG. 7 is an overall configuration diagram showing a flow of the gaseous hydrocarbon treatment / recovery device according to Embodiment 2 of the present invention.
The difference between the second embodiment and the first embodiment is that the three-way switching valve 3a is not used. In the second embodiment, as shown in FIG. 7, the three-way switching valve 3a is not necessary and a valve 21 is newly provided. By adopting such a configuration and making the pressure loss in the recovery device smaller than the set value of the pressure regulating valve 4, gasoline vapor normally flows through the recovery device, and when troubles such as gas clogging occur in the recovery device The gasoline vapor can be automatically discharged to the atmosphere via the pressure regulating valve 4. In addition, since the collection | recovery apparatus of this Embodiment 2 can reduce the usage-amount of adsorption agent very much by the condensation which has two temperature zones, and the pressure loss of the collection | recovery apparatus was reduced to the limit, such an apparatus is realizable. .
Thereby, even if gas clogging occurs in the recovery device, the pressure in the recovery device and the gasoline storage tank 1 does not become higher than the set value of the pressure regulating valve 4, and a safe recovery device can be provided. There is.

Embodiment 3.
FIG. 8 is an overall configuration diagram showing a flow of the gaseous hydrocarbon treatment / recovery device according to Embodiment 3 of the present invention.
In the first embodiment, the suction pump 13 and the pressure pump 14 are continuously installed. However, in the third embodiment, the pressure buffer having a constant volume between the suction pump 13 and the pressure pump 14. By providing the container 31 and the pressure measuring device 32, monitoring the pressure between the suction pump 13 and the pressurization pump 14, it is possible to detect a malfunction of the operation of the suction pump 13 and the pressurization pump 14, which is dangerous. Driving can be prevented. That is, when the pressure between the suction pump 13 and the pressure pump 14 becomes negative, the capacity of the pressure pump 14 decreases, or the pressure between the suction pump 13 and the pressure pump 14 becomes positive. When this happens, it is possible to prevent a reduction in the capacity of the suction pump 13. In addition, by providing a space of a constant volume between the suction pump 13 and the pressurizing pump 14, it is possible to alleviate sudden pressure fluctuations and realize a marginal operation abnormality detection.
Thereby, in the desorption process from the adsorption / desorption towers 11 and 16 in the recovery apparatus, it is possible to detect the malfunction of the suction pump 13 or the pressurization pump 14, and to prevent the rapid expansion of the malfunction, and a safe recovery apparatus. There is an effect that can provide.

Embodiment 4.
FIG. 9 is an overall configuration diagram showing a flow of the gaseous hydrocarbon treatment / recovery device according to Embodiment 4 of the present invention.
The difference between the fourth embodiment and the first embodiment is that the gas treatment flow during regeneration of the first adsorption / desorption tower 11, that is, the second regeneration step shown in the first embodiment is different. In the fourth embodiment, as shown in FIG. 9, the three-way switching valve 3 c is provided not between the suction pump 13 and the pressure pump 14 but between the third condenser 15 and the second adsorption / desorption tower 16. It has been. A pressure controller 19b for adjusting the pressure in the third condenser 15 is provided separately from the pressure controller 19a for adjusting the pressure in the second adsorption / desorption tower 16.
In the first embodiment, the gasoline vapor desorbed from the second adsorption / desorption tower 16 by the suction pump 13 is supplied to the first condenser 9 and passes through the second condenser 10 and the first adsorption / desorption tower 11 to the atmosphere. To be discharged. However, in the fourth embodiment, the gasoline vapor desorbed from the second adsorption / desorption tower 16 by the suction pump 13 is pressurized by the pressurizing pump 14 and supplied to the third condenser 15. Thereafter, the gasoline vapor that has passed through the third condenser 15 passes through the second condenser 10 and the first adsorption / desorption tower 11 and is discharged to the atmosphere. By setting it as such a flow, the pressurization pump 14 can be utilized effectively and the gasoline vapor | steam which passed the 3rd condenser 15 can be collect | recovered efficiently. In addition, when the evaporation temperature of the refrigerant | coolant of the refrigerator 5 cannot be lowered | hung, it is effective to utilize such a flow and there exists an effect which can collect | recover gasoline efficiently.

Embodiment 5.
FIG. 10 is an overall configuration diagram showing a flow of the gaseous hydrocarbon treatment / recovery device according to Embodiment 5 of the present invention.
The difference between the fifth embodiment and the first embodiment is that the gas treatment flow during regeneration of the first adsorption / desorption tower 11, that is, the first regeneration step shown in the first embodiment is different. In the first embodiment, as shown in FIG. 1, the second adsorption / desorption tower 16 is installed in the subsequent stage of the third condenser 15, but in this fifth embodiment, as shown in FIG. The gas storage container 41 is provided at the rear stage of the three condenser 15. Further, 42 is a flow control valve as a mass flow controller provided between the gas storage container 41 and the three-way switching valve 3b, and 43 is a cutoff valve provided between the gas storage container 41 and the third condenser 15.
In Embodiment 1, the gasoline vapor desorbed from the first adsorption / desorption tower 11 by the suction pump 13 is pressurized by the pressurization pump 13 and supplied to the third condenser 15. The gasoline vapor that has passed through the third condenser 15 passes through the second adsorption / desorption tower 16 and is discharged to the atmosphere. However, in this fifth embodiment, the gasoline vapor desorbed from the first adsorption / desorption tower 11 by the suction pump 13 is pressurized by the pressure pump 14 and supplied to the third condenser 15. The process so far is the same as in the first embodiment, but thereafter, the gasoline vapor that has passed through the third condenser 15 is sealed in the gas storage container 41 as it is after being cooled and pressurized and compressed. When the pressure of the gas storage container 41 reaches a predetermined pressure, the first regeneration process ends. Thereafter, the gasoline vapor stored in the gas storage container 41 is supplied to the first adsorption / desorption tower 11 via the flow rate control valve 42, and the gasoline vapor is removed by the adsorbent in the first adsorption / desorption tower 11 to the atmosphere. Discharged. By adopting such a configuration and processing flow, the system configuration can be simplified and the cost of the apparatus can be reduced. Moreover, the operation time of the suction pump 13 and the pressurization pump 14 can be reduced, and energy saving can be aimed at.
From the above, providing the gas storage container 41 instead of the second adsorption / desorption tower 16 has an effect of providing a low-cost and energy-saving recovery device.

Embodiment 6.
FIG. 11 is an overall configuration diagram showing a flow of a gaseous hydrocarbon treatment / recovery device according to Embodiment 6 of the present invention.
The difference between the sixth embodiment and the first embodiment is that the gas treatment flow at the time of regeneration of the first adsorption / desorption tower 11, that is, the first regeneration step shown in the first embodiment is different from the second embodiment. This is the point where the regeneration process is eliminated. Moreover, as shown in FIG. 1, as the component device, as shown in FIG. 1, the inside of the third condenser device 15 was cooled to 0 to 5 ° C. by the temperature medium, but in this Embodiment 6, As shown in FIG. 11, the fourth condensing device 51 that can be directly cooled by the refrigerant from the refrigerator 5 is provided, and the second adsorption / desorption tower 16 is eliminated.
In the first embodiment, the gasoline vapor desorbed from the first adsorption / desorption tower 11 by the suction pump 13 is pressurized by the pressure pump 14 and supplied to the third condenser 15. The gasoline vapor that has passed through the third condenser 15 passes through the second adsorption / desorption tower 16 and is discharged to the atmosphere. However, in the sixth embodiment, the gasoline vapor desorbed from the first adsorption / desorption tower 11 by the suction pump 13 is pressurized by the pressurizing pump 14 and supplied to the fourth condenser 51. The interior of the fourth condensing device 51 is directly cooled by the refrigerant cooled by the refrigerator 5 and is about -30 ° C. Under the conditions of a pressure of 0.3 MPa and a cooling temperature of −30 ° C., the gasoline vapor concentration is about 1 vol%. Therefore, it is released into the atmosphere as it is. As a result, the system configuration can be simplified and the cost of the apparatus can be reduced. In addition, the third regeneration step can be eliminated, the operation time of the suction pump 13 and the pressure pump 14 can be reduced, and energy saving can be achieved.
From the above, providing the fourth condensing device 51 instead of the third condensing device 15 has an effect of providing a low-cost and energy-saving recovery device.

Embodiment 7.
FIG. 12 is an overall configuration diagram showing a flow of the gaseous hydrocarbon treatment / recovery device according to Embodiment 7 of the present invention.
The difference between the seventh embodiment and the first embodiment is that the third adsorption / desorption tower 61 having the same performance and size as the first adsorption / desorption tower 11 is provided in parallel with the first adsorption / desorption tower 11. The second adsorption / desorption 16 is eliminated. That is, the first adsorption / desorption tower 11 is different in that the gasoline vapor discharged from the second condenser 10 is adsorbed and at the same time the gasoline vapor adsorbed from the third adsorption / desorption tower 61 is desorbed.

  In the figure, 61 is the same specification as the first adsorption / desorption tower 11, the third adsorption / desorption tower provided in parallel with the first adsorption / desorption tower 11, and 62 a, 62 b are gasoline discharged from the second condenser 10. The adsorption valves 63a and 63b for introducing the vapor to the first adsorption / desorption tower 11 or the third adsorption / desorption tower 61 are used for desorbing gasoline vapor from the first adsorption / desorption tower 11 or the third adsorption / desorption tower 13. Valves 64a and 64b are exhaust valves for discharging gasoline vapor treated from the first adsorption / desorption tower 11 or the third adsorption / desorption tower 13 to the atmosphere, and 65a and 65b are the first adsorption / desorption tower 11 or the third adsorption / desorption tower. 13 is a gas flow rate adjusting valve that introduces air into the first adsorption / desorption tower 11 or the third adsorption / desorption tower 13 when gasoline vapor is desorbed from the gas.

  Next, the operation will be described. The operation of the apparatus shown in the seventh embodiment is normally performed in two steps, an adsorption process and a regeneration process. First, the adsorption process will be described. When gasoline refueling is started, the three-way switching valve 3a is switched to the recovery device side. When the three-way switching valve 3a is switched and refueling is started from a tank truck or the like to the gasoline storage tank 1 through the gasoline refueling pipe 2, the gasoline vapor filled in the gasoline storage tank 1 is discharged from the gasoline storage tank 1. The The gasoline concentration of the gasoline vapor at this time is about 30 to 40 vol% at normal temperature. Gasoline vapor discharged from the gasoline storage tank 1 is sent to the first condenser 9 via the three-way switching valve 3a. The first condensing device 9 is indirectly cooled by the temperature medium cooled by the refrigerator 5 being supplied by the liquid circulation pump 8. Usually, the inside of the first condensing device 9 is maintained at about 0 ° C. to 5 ° C., and a portion of gasoline vapor and moisture contained in the gas are condensed and gas is formed by a gas-liquid separator (not shown) or the like. (Gasoline vapor) and liquid (gasoline). The liquid accumulates below the first condenser 9 and is returned to the gasoline storage tank 1 via the gasoline pipe 18.

  Subsequently, about 20 vol% of gasoline vapor that could not be processed by the first condenser 9 is supplied to the second condenser 10. The second condenser 10 is directly cooled by supplying the refrigerant cooled by the refrigerator 5 to the second condenser 10. Usually, the inside of the second condensing device 9 is maintained at about −20 ° C. to −10 ° C., part of the gasoline vapor is condensed, separated into gas (gasoline vapor) and liquid (gasoline), and not condensed. Only gasoline vapor is discharged. The liquid accumulates below the first condenser 9 and is returned to the gasoline storage tank 1 via the gasoline pipe 18. In the first embodiment, when the gasoline vapor discharged from the gasoline storage tank 1 is adsorbed, the desorption operation is not performed. Therefore, when the adsorption operation is completed, the cooling of the second condenser 10 is stopped. It was. However, in the seventh embodiment, when the gasoline vapor discharged from the gasoline storage tank 1 is adsorbed, the gasoline vapor is desorbed from the other adsorption / desorption tower. However, the cooling of the second condenser 10 is not stopped.

  Subsequently, about 8 vol% of gasoline vapor that could not be processed by the second condenser 10 is sent to the adsorption / desorption towers 11 and 61 for processing. FIG. 12 shows a case where 11 is operating as an adsorption tower and 61 is operating as a desorption tower. Accordingly, the suction valve 62a is open (black), and 62b (white) is closed. After adsorption treatment for an arbitrary time as an adsorption tower, it is used as a desorption tower. In this case, the suction valve 62a is closed and 62b is opened. Further, when the desorption of gasoline is completed, it is used again as an adsorption tower, and this operation is repeated over time. Switching between adsorption and desorption is controlled by switching the adsorption valves 62a and 62b as described above. The adsorption / desorption towers 11 and 61 are filled with an adsorbent that adsorbs gasoline vapor. By passing gasoline vapor through the adsorbent, the gasoline components are adsorbed and removed, and become clean air having a gasoline concentration of 1 vol% or less and released to the atmosphere through the exhaust valve 64a. The adsorption / desorption towers 11 and 61 are always cooled to a constant temperature by the temperature medium supplied by the liquid circulation pump 8 regardless of the role of gasoline vapor adsorption / desorption. That is, the operation of the cooling system of the first condenser 9 and the adsorption / desorption towers 11 and 61 is always controlled so as to be maintained at the set temperature.

  Next, the gasoline vapor desorption process will be described. When desorbing gasoline adsorbed on the adsorbent, the suction pump 13 sucks gas from the adsorption / desorption tower 61 to desorb the gasoline from the adsorbent. At this time, the removable valve 63b is opened and the 63a is closed. At the time of adsorption, the adsorption tower operates in an atmospheric pressure state of 0.1 MPa, but at the time of desorption, the pressure is reduced to the atmospheric pressure or less by the suction pump 13, so that the gasoline adsorbed on the adsorbent is desorbed by this pressure difference. The desorbed gasoline vapor is pressurized by the pressure pump 14 and supplied to the third condenser 15. The pressure inside the third condenser 15 is maintained at a high pressure of 0.3 MPa by the pressure controller 19, and the gasoline vapor is liquefied and recovered with high efficiency. The gasoline vapor discharged from the pressure controller 19 is returned to the second condensing device 9, and after the gasoline is condensed and recovered again, it is returned to the adsorption / desorption tower 11 again. While this operation is repeated, the entire amount of gasoline is condensed and recovered in the condensers 9, 10 and 15.

  Since only the desorption method using the pressure difference due to the suction of the suction pump 13 is not very efficient, it is effective to introduce the purge gas from the outside. In the seventh embodiment, a part of clean gas discharged from the adsorption / desorption tower 11 to the atmosphere via the gas flow rate adjusting valve 65b is sent to the desorption tower 61 as the purge gas. In this case, the gas flow rate adjustment valve 65b is in a state in which a specified amount of gas can flow in an open state, and the gas flow rate adjustment valve 65a is closed so that no gas flows. In the seventh embodiment, the amount of moisture in the gas is sufficiently lowered in the first condensing device 9 in the previous stage, so that the moisture contained in the purge gas adversely affects the adsorbent in the third adsorption / desorption tower 61. There is almost nothing.

Refueling a gasoline storage tank at a gas station is usually performed regularly for a certain period of time. For this reason, the generation of gasoline vapor is limited to a certain time of the day. Therefore, from the viewpoint of increasing the operating rate of the apparatus, the present embodiment performs the adsorption operation and the desorption operation at the same time. Therefore, the adsorption operation and the desorption operation can be performed in series, and the desorption time is lengthened. It can be said that the operation rate is lower than that of the first embodiment that it is possible. However, since the adsorption operation and the desorption operation are performed simultaneously, the cooling can be stopped when the adsorption operation or the desorption operation is not performed, that is, when the gasoline vapor is not recovered, and the energy used for the cooling is reduced. It can be called energy-saving equipment.
From the above, energy saving and efficient gasoline recovery can be performed by performing the operation while simultaneously performing the adsorption operation and the desorption operation.

  Next, switching of the adsorption / desorption towers 11 and 61 will be described. In this Embodiment 7, the case where the adsorption / desorption towers 11 and 61 are switched using a timer will be described. As described above, the gasoline vapor passes through the first adsorption / desorption tower 11 to adsorb and remove gasoline components, and becomes a clean air having a gasoline concentration of 1 vol% or less and is released to the atmosphere through the discharge valve 64a. However, as the amount of gasoline vapor supplied to the first adsorption / desorption tower 11 increases, the adsorption capacity of the first adsorption / desorption tower 11 gradually decreases. When this state continues and the gasoline concentration at the outlet of the first adsorption / desorption tower 11 approaches 1 vol%, the adsorption / desorption towers 11 and 61 need to be switched. In the gas station, refueling to the gasoline storage tank 1 is periodically performed for a certain period of time. Therefore, the simplest control is simply to switch over a certain period of time after the start of recovery. Therefore, it is effective to switch the adsorption / desorption towers 11 and 61 at regular time intervals when the three-way switching valve 3a is switched or when the recovery device is operated. Further, as an actual switching operation, it is preferable to perform switching so that gasoline vapor always flows without creating the state where the adsorption valves 62a and 62b are closed simultaneously. That is, when adsorbed by the first adsorption / desorption tower 11 and desorbed by the third adsorption / desorption tower 61, the closed adsorption valve 62b, desorption valve 63a, and discharge valve 64b are opened and then originally opened. It is better to perform switching by closing the suction valve 62a, the detaching valve 63b, and the discharge valve 64a. As a result, no gasoline vapor is prevented from being supplied to the adsorption / desorption towers 11 and 61, the gasoline refueling speed to the gasoline storage tank 1 is not slowed, and the pressure in the gasoline storage tank 1 is not increased. A safe gasoline recovery device can be provided.

  Finally, a control method for the gaseous hydrocarbon treatment / recovery device of the seventh embodiment will be described. When the recovery device is stopped, the suction pump 13 and the pressure pump 14 are stopped, the suction valves 62a and 62b, the detaching valves 63a and 63b, and the discharge valves 64a and 64b are fully closed, and the gas flow rate adjusting valves 65a and 65b are closed. Is closed. When the three-way switching valve 3a is switched and refueling is started, an operation signal is received, for example, a switching signal for the three-way switching valve 3a is received, and the suction valve 62a, the detachment valve 63b, and the discharge valve 64a are opened. When refueling to the gasoline storage tank 1 is started, gasoline vapor flows into the first condenser 9, the second condenser 10, and the first adsorption / desorption tower 11. Simultaneously with the start of the adsorption operation, the suction pump 13 and the pressure pump 14 are operated. When the pressure in the third adsorption / desorption tower 61 decreases to a predetermined concentration due to the operation of the suction pump 13, the gas flow rate adjustment valve 65 b starts to open, and the gas flow rate adjustment valve 65 b so that the predetermined flow rate flows through the third adsorption / desorption tower 61. Is controlled.

  When refueling is continued for a certain time in this way, the adsorption / desorption towers 11 and 61 are switched. When a switching signal is received from a timer or the like, as described above, the suction valve 62b, the detachment valve 63a, and the discharge valve 64b that have been closed are opened and the gas flow rate adjustment valve 65b is closed. Next, the adsorption valve 62a, the desorption valve 63b, and the exhaust valve 64a are opened, the third adsorption / desorption tower 61 becomes an adsorption operation, and the first adsorption / desorption tower 11 becomes a desorption operation. When the pressure in the third adsorption / desorption column 61 decreases to a predetermined pressure due to the operation of the suction pump 13, the gas flow rate adjustment valve 65 b starts to open, and the gas flow rate adjustment valve 65 b so that the predetermined flow rate flows through the third adsorption / desorption column 61. Is controlled. When the switching operation is repeated in such a procedure and the oil supply to the gasoline storage tank 1 is stopped, the three-way switching valve 3a is switched, and the suction pump 13 and the pressure pump 14 are stopped in response to the stop signal, and the gas The flow rate adjustment valve 65b is closed, and the adsorption valve 62a, the detachment valve 63b, and the exhaust valve 64a are closed.

  As described above, the gaseous hydrocarbon treatment / recovery device according to the seventh embodiment combines the condensing devices 9 and 10 and the adsorption / desorption towers 11 and 61 in the two temperature zones, so that the maximum is 1 vol%. This is a gaseous hydrocarbon treatment / recovery device that only emits gasoline vapor and has a very low environmental impact. Moreover, since only 1 vol% of gasoline vapor is discharged at the maximum, 39 vol% of 40 vol% of gasoline vapor can be recovered, and the recovery efficiency is 97.5%, which is a very high efficiency recovery device. Further, since the adsorption operation is performed after the condensation operation, the adsorption / desorption towers 11 and 61 can be downsized, and the entire apparatus can be downsized. Furthermore, since the adsorption operation and the desorption operation are performed at the same time, useless operation can be reduced and the running cost can be reduced.

Embodiment 8.
FIG. 13 is an overall configuration diagram showing a flow of a gaseous hydrocarbon treatment / recovery device according to Embodiment 8 of the present invention.
The difference between the eighth embodiment and the seventh embodiment is that the flow of gas treatment during regeneration of the first adsorption / desorption tower 11 is different. Moreover, as a component apparatus, in Embodiment 8, as shown in FIG. 13, the pressurizing pump 14, the third condensing device 15, and the pressure controller 19 in FIG. 12 are not provided.
In Embodiment 7, the gasoline vapor desorbed from the third adsorption / desorption tower 61 by the suction pump 13 is pressurized by the pressurizing pump 14 and supplied to the third condenser 15. The gasoline vapor that has passed through the third condenser 15 passes through the second condenser 10 and the first adsorption / desorption tower 11 and is discharged to the atmosphere. However, in the eighth embodiment, the gasoline vapor desorbed from the first adsorption / desorption tower 11 by the suction pump 13 is supplied to the first condenser 9. The first condensing device 9 merges with the gasoline vapor discharged from the gasoline storage tank 1, passes through the second condensing device 10 and the first adsorption / desorption tower 11, and is discharged to the atmosphere. As a result, the system configuration can be simplified and the cost of the apparatus can be reduced.
From the above, by eliminating the pressurizing pump 14, the third condensing device 15, and the pressure controller 19, there is an effect that it is possible to provide a low-cost and energy-saving recovery device.

Embodiment 9.
FIG. 14 is an overall configuration diagram showing a flow of a gaseous hydrocarbon treatment / recovery device according to Embodiment 9 of the present invention.
The difference between the ninth embodiment and the seventh embodiment is that the gas treatment flow during regeneration of the first adsorption / desorption tower 11 is different. Moreover, as shown in FIG. 12, in the seventh embodiment, the inside of the third condenser 15 was cooled to 0 to 5 ° C. by the temperature medium in the seventh embodiment. As shown in FIG. 14, it is the point provided with the 4th condensation apparatus 51 which enabled it to cool directly from the refrigerator 5 with a refrigerant | coolant.
In Embodiment 7, the gasoline vapor desorbed from the first adsorption / desorption tower 11 by the suction pump 13 is pressurized by the pressurizing pump 14 and supplied to the third condenser 15. The gasoline vapor that has passed through the third condenser 15 passes through the second condenser 10 and the first adsorption / desorption tower 11 and is discharged to the atmosphere. However, in the ninth embodiment, the gasoline vapor desorbed from the first adsorption / desorption tower 11 by the suction pump 13 is pressurized by the pressure pump 14 and supplied to the fourth condensing device 51. The interior of the fourth condensing device 51 is directly cooled by the refrigerant cooled by the refrigerator 5 and is about -30 ° C. Under conditions of a pressure of 0.3 MPa and a cooling temperature of −30 ° C., the concentration of gasoline vapor is about 1 vol% and is supplied to the first adsorption / desorption tower 11. As a result, the amount of gasoline vapor adsorbed and removed by the first adsorption / desorption tower 11 can be reduced, the switching time of the adsorption / desorption towers 11 and 61 can be lengthened, and the life of the valve can be extended. In addition, since the number of times of valve switching can be reduced, more stable operation can be realized.
From the above, providing the fourth condensing device 51 instead of the third condensing device 15 has an effect of providing a low-cost and highly reliable recovery device.

It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 1 of this invention. It is a characteristic view which shows the relationship between cooling temperature and a silica gel filling amount. It is a characteristic view for demonstrating the control method of purge gas amount. It is a characteristic view which shows the relationship between a process gas flow rate and a recovery rate. It is a characteristic view which shows the relationship between an internal pressure and a silica gel important amount. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 1 of this invention. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 2 of this invention. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 3 of this invention. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 4 of this invention. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 5 of this invention. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 6 of this invention. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 7 of this invention. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 8 of this invention. It is a whole block diagram which shows the flow of the processing and collection | recovery apparatus of the gaseous hydrocarbon which concerns on Embodiment 9 of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Gasoline storage tank, 2 Refueling pipe, 3 Three way switching valve, 4 Pressure control valve, 5 Refrigerator, 6 Heat exchanger, 7 Temperature medium tank, 8 Liquid circulation pump, 9 1st condensing device, 10 2nd condensing device, 11 First adsorption / desorption tower, 12 Two-way valve, 13 Suction pump, 14 Pressure pump, 15 Third condenser, 16 Second adsorption / desorption tower, 17 Flow control valve, 18 Gasoline piping, 19 Pressure controller, 21 Valve, 31 pressure buffer container, 32 pressure measuring instrument, 41 gas storage container, 42 mass flow controller, 43 shutoff valve, 51 fourth condenser, 61 third adsorption / desorption tower, 62 adsorption valve, 63 desorption valve, 64 exhaust valve, 65 Gas flow control valve.

Claims (3)

In a device that collects gasoline vapor that leaks during refueling from a gasoline storage facility,
A first condensing device that removes moisture and gasoline vapor contained in the gasoline vapor, a second condensing device that removes the gasoline vapor provided downstream of the gas after the first condensing device, and the second condensing device A first adsorption / desorption device provided on the downstream side of the gas in the rear stage, a suction pump for extracting gasoline vapor from the first adsorption / desorption device, a pressure pump for pressurizing the gasoline vapor extracted by the suction pump, and pressure A gasoline vapor treatment / recovery device, comprising: a third condenser for removing gasoline vapor; and a second adsorption / desorption tower for collecting gasoline vapor that could not be collected by the third condenser. A finned tube heat exchanger is provided inside the adsorption / desorption device, and a silica gel or synthetic zeolite having a pore diameter of 4 to 100 angstrom as an adsorbent is packed between the fins of the finned tube heat exchanger or a mixture thereof. processing and recovery system of the gaseous hydrocarbons according to claim 1 Symbol mounting characterized. The cooling temperature of the first condensing device is reduced to 0 using a cooling path for cooling using a temperature medium whose temperature is controlled by the refrigeration or cooling apparatus and a cooling path for cooling using a refrigerant filled in the refrigeration or cooling apparatus. ° C. 5 ° C. from, -10 ° C. -30 ° C. or higher the cooling temperature of the second condenser apparatus following claim 1 or claim 2 Symbol the cooling temperature of the adsorption-desorption apparatus and controls the 5 ° C. from 0 ℃ Equipment for treating and recovering gaseous hydrocarbons.

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