JPH09324183A - Recovery of gasoline vapor and production of recovery equipment therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for recovering gasoline vapor, capable of recovering a discharge gas containing gasoline vapor without carrying out construction for burying underground or construction for connecting piping to a storage tank and provide a recovery equipment therefor. SOLUTION: This method for recovering gasoline vapor comprises recovering discharge gas containing gasoline vapor evolved from a fuel tank 8 for automobiles during oil feeding through a suction line 22 comprising suction piping when gasoline is fed from an underground tank 9 for storing the gasoline through a solution sending line 21 comprising feed oil piping to the fuel tank 8. In the method, a liquefier 5 is connected to the suction line 22 to liquefy the recovered discharge gas containing gasoline vapor in the liquefier 5, and the recovered liquefied gasoline is joined to the solution sending line 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering gasoline vapor and a recovery device therefor. This method and apparatus are suitable for recovering a gasoline vapor-containing exhaust gas consisting of a mixed gas of gasoline vapor and air generated at a filler port when refueling from a large tank that stores gasoline to another small tank. Used.

[0002]

2. Description of the Related Art A gasoline refueling device called a meter is used to refuel a tank truck or a general vehicle from a gasoline storage tank installed underground or above ground at a gasoline refueling station.

In general, this meter is composed of a gasoline liquid feed pump, an oil supply pipe, and instruments for controlling the liquid feed state in order to make the liquid feed its main function, and supplies gasoline. In many cases, the function of treating exhaust gas containing gasoline vapor generated at the fuel filler port is not added.

Exhaust gas containing gasoline vapor includes the amount of residual gas in the tank on the refueling side that is replaced with the delivered gasoline and discharged, and the amount that evaporates due to contact with the outside air at the refueling port. is there. In any case, the concentration of gasoline vapor in the exhaust gas containing gasoline vapor is often as high as several vol% or more corresponding to the saturated vapor pressure of gasoline at the ambient temperature during refueling.

[0005] Therefore, it is not preferable to discharge these gasoline vapor-containing exhaust gas into the atmosphere without treatment, which is not preferable because it pollutes the environment, but also leads to loss of fuel. A refueling device incorporating the recovery processing function has been put into practical use. The most common recovery method is the "steam replacement method" in which an intake pipe is provided in parallel with a refueling pipe, and exhaust gas containing gasoline vapor is passed through it to recover it in the original storage tank without releasing it to the atmosphere.

In the steam displacement method, as shown in FIG. 2, a liquid feed line 6 consisting of a liquid feed pump 6 for feeding gasoline from an underground tank 9 to a fuel tank 8 of an automobile passing through the meter 1 and an oil feed pipe is provided. In addition, an intake line 22 consisting of a gas pipe for flowing gasoline vapor-containing exhaust gas in the opposite direction in parallel with the oil supply pipe has been added. The intake pump 7 for sucking gas may or may not be attached. The collection efficiency in the intake line is 95% for the former and 70% for the latter. An exhaust line 23 is provided to keep the inside of the underground tank 9 at atmospheric pressure.

Further, various methods such as a classical adsorption method and a separation membrane method have been proposed or put into practical use as a method for improving the recovery efficiency of the exhaust gas containing gasoline vapor after collection into the original tank. (For example, Separation Science and Technology, 30 (1995) 1625-1638). The separation membrane method is a relatively new technology that utilizes a gas separation membrane that selectively permeates gasoline vapor, and as shown in FIG. 3, the prefilter 3 and the gas separation membrane 2 are connected to the intake line 22 following the intake pump 7. And a vacuum pump 11 are connected, and the gasoline vapor in the exhaust gas containing gasoline vapor is permeated by the differential pressure generated on both sides of the gas separation membrane 2 by the action of the vacuum pump, and is returned to the original underground tank 9 through the concentration line 24. It is to be collected.

[0008]

As shown in FIGS. 2 and 3, in order to carry out the conventional recovery method at an existing gas station, a new measuring instrument incorporating a recovery function is used as an existing measuring instrument. In addition to the work for exchanging with, the piping work for connecting the intake line 22 as shown in FIG. 2 or the concentration line 24 as shown in FIG. 3 to the storage tank 9 is required. When the storage tank is an underground tank, the piping work is underground burial work, which requires a great deal of cost. And, most of the storage tanks in general gasoline filling stations are underground installation type.

Therefore, an object of the present invention is to provide a gasoline vapor recovery method and a recovery apparatus therefor capable of recovering exhaust gas containing gasoline vapor without performing underground burial work and connection piping work with a storage tank. To provide.

[0010]

In order to achieve the above object, a method for recovering gasoline vapor according to the present invention comprises a first tank for storing gasoline to a second tank having a smaller capacity than the first tank. When refueling gasoline through a liquid delivery line consisting of a refueling pipe, a liquefier is connected to the intake line in a recovery method in which exhaust gas containing gasoline vapor generated from the second tank during refueling is recovered through an intake line consisting of a suction pipe. Then, the exhaust gas containing the gasoline vapor to be recovered is liquefied by the liquefier, and the liquefied recovered gasoline is joined to the liquid sending line.

Further, a gasoline vapor recovery device suitable for this gasoline vapor recovery method is an oil supply pipe for supplying gasoline from a first tank for storing gasoline to a second tank having a smaller capacity than the first tank. In addition to the liquid feed line consisting of, a recovery device having an intake line consisting of a suction pipe for recovering exhaust gas containing gasoline vapor generated from the second tank during refueling, is connected to the intake line and recovered from the intake line. And a liquefier for liquefying the exhaust gas containing gasoline vapor, and a recovery liquid line connected to the liquefaction device and the liquid supply line for joining the recovered gasoline liquefied by the liquefier to the liquid supply line. .

According to the present invention, the gasoline vapor-containing exhaust gas collected in the intake line is once liquefied, so that the liquefied recovered gasoline can be joined to the liquid supply line. And since the liquid transfer line is on the ground, by installing a confluence point at a convenient position on the ground, the exhaust gas containing gasoline vapor can be recovered without the need for underground burying work or connection work with storage tanks. And can be used as fuel.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of a gasoline vapor recovery method and a recovery apparatus of the present invention will be described with reference to FIG. The recovery device of this example is assembled to a measuring instrument 1 for refueling an automobile at a gasoline service station.

The gasoline stored in the underground tank 9 is
Oil is supplied to the fuel tank 8 of the automobile through the liquid supply line 21 by the liquid supply pump 6 installed inside the measuring instrument 1. Exhaust gas containing gasoline vapor (hereinafter, simply referred to as "exhaust gas") generated at the fuel filler port of the fuel tank 8 during the fueling.
Is collected through the intake line 22 by the intake pump 7 adjusted to have the same volume speed as the liquid delivery pump 6. Up to this stage, it is the same as in FIG.

In this example, a gas separator 1 for selectively passing gasoline vapor, a prefilter 3, a compressor 4 as a differential pressure generating means, and a liquefier 5 are provided inside the meter 1. Then, the exhaust gas collected in the intake line is first dust-removed by the pre-filter 3 and guided to the liquefier 5. The liquefier 5 is an indirect heat exchange-type cooling condenser that indirectly cools the exhaust gas dedusted by the gasoline in the oil supply pipe as the oil supply pipe of the liquid supply line 21 passes through the inside thereof. Therefore, when the gasoline vapor in the exhaust gas has a partial pressure equal to or higher than the saturated vapor pressure at this cooling temperature, it is partially liquefied in the liquefier 5 and returned to the liquid sending line 21 through the recovery liquid line 25. Since the gasoline flowing through the liquid supply line 21 is used as the cooling medium in this way, it is not only economical, but it is not necessary to provide a separate pipe for the cooling medium, and therefore the volume occupied by the measuring instrument 1 can be small. Incidentally, since the recovery liquid line 25 once descends and then ascends and is connected to the liquid sending line 21, the descending portion serves as a liquid reservoir to prevent backflow.

On the other hand, the residual gas that has not been liquefied by the liquefier 5 is pressurized by the compressor 4 and sent to the separation membrane 2. A pressure control valve 31 is installed on the non-permeable side of the separation membrane 2 to keep the pressure on the supply side constant. The separation membrane 2 has a function of separating gasoline vapor and air, and the permeated side of the separation membrane 2 discharges the gas in which the gasoline vapor is concentrated, returns to the liquefier 5 through the concentration line 24, and liquefies and recovers again. . Therefore, the recovery rate is improved. On the other hand, on the non-permeate side of the separation membrane 2, a gas obtained by diluting gasoline vapor is discharged and released to the atmosphere through the exhaust line 23. Since the concentration of gasoline vapor in the released gas is extremely low, it does not pollute the environment.

The separation membrane 2 is preferably one that selectively and efficiently separates gasoline vapor and air and has durability against exhaust gas containing gasoline vapor. For example, an asymmetric polyimide membrane or a silicone homogeneous membrane, or There is a composite film obtained by coating these films in a composite manner. Further, the shape of the membrane is preferably a hollow fiber membrane or a flat membrane, and the shape of the membrane module is a hollow fiber type, a spiral type, a plate & frame type or the like.

As the rotating equipment such as the liquid feed pump 6, the suction pump 7, the compressor 4, etc., it is preferable that the lines do not mix impurities other than the fluid to be handled and have resistance to the fluid to be handled. For example, centrifugal pumps, diaphragm pumps, piston pumps, magnet pumps, etc. are used for liquid feed pumps, and centrifugal pumps, dry volume pumps, etc. for suction pumps and compressors.
There are turbo type and screw type.

The pre-filter 3 is preferably one which can remove dust in the exhaust gas and is resistant to the fluid to be handled. For example, a filter having a pore size of 0.1 to 100 μm and made of a resin such as polypropylene, polyethylene, or polyester, or a stainless steel can be used.

The liquefier 5 is preferably one that can efficiently liquefy gasoline vapor near the saturated vapor pressure. For example, the indirect heat exchange type includes a coil type, a multi-tube type, a jacket type, and the direct gas-liquid contact type includes a tray type, a liquid film type, and an aeration type. As the cooling medium, if it is an indirect heat exchange type, tap water or cooling water for the cooling tower can be selected in addition to gasoline itself in the liquid transfer line as described above, but if it is a direct gas-liquid contact type, it is limited to gasoline itself. It

As the differential pressure generating means, (1) a compressor or a blower is provided between the supply side of the gas separation membrane and the liquefier.
(2) A compressor or a blower may be provided between the supply side of the gas separation membrane and the liquefier, and a vacuum pump may be provided between the permeate side of the gas separation membrane and the liquefier. The former is economical because it requires only one device to generate the differential pressure. The latter can obtain a larger differential pressure than the former. The pipes for liquid supply and intake from the measuring instrument 1 to the fuel tank 8 are made into a double pipe that holds both of them at the same time, one pipe is arranged side by side, and one pipe is bundled into one pipe and integrated into one pipe. Either of the methods of treating separately may be used.

[0022]

EXAMPLE This is an example of obtaining a recovery rate of exhaust gas when a fueling device with a recovery device having the flow of FIG. 1 is used in a gasoline service station. The specifications of each device are as follows. Although not shown, the metering pump measures the amount of gasoline to be supplied to the tank 8 of the automobile through each liquid feeding line 21, and in this example, two pumps were operated simultaneously.

[Device Specifications] Pre-filter: Cartridge type (3 m ³ / hr × 5μ) 1 unit Separation membrane: Spiral type, effective membrane area approx. 6 m ² 1 (NTGS-2200-S4PX manufactured by Nitto Denko Corporation) Liquefaction machine : Coil type indirect heat exchange type cooling condenser 1 compressor: Gasoline liquid sealed volumetric 1 (maximum 18m / hr x 2.5atm x 2.2KW) Intake pump: Gasoline liquid sealed centrifugal 2 (standard 35L / min / platform × H ₂ 0) metering pumps: two centrifugal (standard 35L / min / platform × 0.5kg / cm ² G)

As a result of measuring the material balance data under steady load under the above conditions, the values shown in Table 1 were obtained. When the recovery rate of gasoline vapor was calculated from these values based on the following calculation formula, the recovery rate was 96.5%. Therefore, it became clear that gasoline vapor can be collected at a high rate without the need for underground construction work and pipe connection work with the storage tank of the refueling source. Recovery rate = 100 × [1-F (flow rate × ΣC _n ) / G (flow rate × ΣC _n )]

[0025]

[Table 1]

[0026]

EFFECTS OF THE INVENTION According to the present invention, gasoline vapor can be collected at a high rate without constructing underground burial work or pipe connection work with a storage tank at the refueling source, which is very economical for gasoline refueling companies. Protect the environment without burdening
In addition, resources can be saved, which is beneficial.

[Brief description of drawings]

FIG. 1 is a basic flow chart of an oil supply device having a recovery function by a vapor replacement method which is a conventional recovery method.

FIG. 2 is a basic flow diagram of an oil supply device in which a vapor displacement method is combined with a separation membrane method.

FIG. 3 is a basic flow diagram of an oil supply device equipped with a recovery device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Meter 2 Gas Separation Membrane 3 Pre-filter 4 Compressor (Differential Pressure Generating Means) 5 Liquefier 6 Liquid Delivery Pump 7 Intake Pump 8 Fuel Tank 9 Underground Tank 21 Liquid Delivery Line 22 Intake Line 23 Exhaust Line 24 Concentration Line 25 Recovery Liquid line 31 Pressure control valve

Claims (8)

[Claims] 1. When refueling gasoline from a first tank for storing gasoline to a second tank having a smaller capacity than the first tank through a liquid delivery line formed of refueling piping, the second tank is refueled during refueling. In a recovery method for recovering gasoline vapor-containing exhaust gas generated from a tank through an intake line consisting of a suction pipe, a liquefier is connected to the intake line, and the recovered gasoline vapor-containing exhaust gas is liquefied and liquefied by the liquefier. A method for recovering gasoline vapor, characterized in that recovered gasoline is joined to a liquid transfer line. 2. The gasoline vapor recovery method according to claim 1, wherein the gasoline flowing through the liquid supply line is used as a cooling medium for the liquefier. 3. A gas separation membrane which selectively permeates gasoline vapor is connected to a liquefier, and a residual gas which is not liquefied by the liquefier is sent to the gas separation membrane, and the dilution is discharged from the non-permeate side of the gas separation membrane. The gasoline vapor recovery method according to claim 1 or 2, wherein the concentrated gas discharged from the permeation side is returned to the liquefier while the gas is released to the atmosphere. 4. A second line during refueling, together with a liquid feed line comprising a refueling pipe for refueling gasoline from a first tank for storing gasoline to a second tank having a smaller capacity than the first tank. A liquefier, which is connected to the intake line and liquefies the exhaust gas containing gasoline vapor, which collects the exhaust gas containing gasoline vapor, which is generated from the tank, is connected to the intake line. And a recovery liquid line for connecting the recovery gasoline liquefied by the liquefier to the liquid supply line, the gasoline vapor recovery device being characterized by comprising: 5. The gasoline vapor recovery apparatus according to claim 4, wherein the liquefier uses gasoline flowing through the liquid supply line as a cooling medium. 6. A gas separation membrane which selectively permeates gasoline vapor and has a supply side and a permeation side connected to a liquefier and a non-permeation side communicating with the atmosphere, and a pressure difference between both sides of the gas separation membrane. The gasoline vapor recovery apparatus according to claim 4 or 5, further comprising a pressure generating means. 7. The gasoline vapor recovery apparatus according to claim 6, wherein the differential pressure generating means is a compressor or a blower provided between the gas separation membrane supply side and the liquefier. 8. A differential pressure generating means is provided with a compressor or an air blower provided between the gas separation membrane supply side and the liquefier, and a vacuum provided between the gas separation membrane permeate side and the liquefier. The gasoline vapor recovery device according to claim 6, which is a pump.