JP2007244933A - Adsorption tower of gasoline vapor recovery apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an adsorption tower of a gasoline vapor apparatus with a high cooling speed of an adsorbent by computerizing the optimum range by combining heat exchanger fines and different particle diameters of an adsorbent, which are constituent factors of the adsorption tower. <P>SOLUTION: The gasoline vapor recovery apparatus comprises a heat source unit 1, a gasoline condensation unit 2, and a brine condensation unit 3; wherein the heat source unit comprises a refrigerant circulation channel, the gasoline condensation unit 2 comprises a gasoline supply nozzle 9, a gasoline suction pump 10, and a gasoline vapor condensation pipe 12, and the brine condensation unit 3 comprises a brine tank 11, a brine pump 13, and a heat medium circulation pipe 16. The adsorption tower 4 comprises an adsorption tower container 14, an adsorbent 15, and a fin type heat exchanger having the heat medium circulation pipe and plate fins 17. The spaces between neighboring fins of the fin type heat exchanger is filled with the granular adsorbent. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention provides an adsorbent in a gasoline vapor recovery device for liquefying and recovering and reusing vaporized gasoline (gasoline vapor) that is released into the atmosphere when refueling at a gas station. It relates to a packed adsorption tower.

In a gasoline tank of an automobile or the like, gasoline vapor exists in a saturated state at a place other than a portion where liquid gasoline exists. For this reason, when refueling at a gas station, almost the same amount of gasoline vapor as the liquid gasoline supplied is discharged into the atmosphere, causing photochemical smog, which is regarded as a problem.
Therefore, at present, a gasoline vapor recovery device has been proposed in order to be able to be reused by cooling and liquefying and recovering the gasoline vapor.
Of the methods for recovering gasoline vapor, a method for recovering gasoline vapor using an adsorbent is generally used as an adsorption tower, which is an apparatus for filling and adsorbing an adsorbent. Further, the adsorbent is cooled in order to improve the adsorption performance in a low temperature state. As a cooling method, there is generally a method of filling an adsorbent between fin-type heat exchangers using a plurality of fins (see, for example, Patent Document 1).
In addition, the gasoline vapor recovery device liquefies and recovers gasoline vapor at ambient temperature that is released into the atmosphere during refueling to a concentration of about 10 vol% by cooling with a refrigerant. The concentration of gasoline vapor released into the atmosphere is reduced to less than 1 [vol%] by flowing into and adsorbing to the adsorbent at a low temperature in the adsorption tower where cooling is performed using a heat exchanger. Is. For fin-type heat exchangers used in adsorption towers, if the adsorbent particle size is small, the airflow resistance increases in the fluidized bed, and the amount of adsorption may be reduced. There may be problems such as the influence of the outside of the apparatus on the outside of the apparatus, or the performance deterioration from the powder breakage of the adsorbent itself due to the vibration of the particles in the fluidized bed. On the other hand, when the particle size of the adsorbent is large, the adsorbent filling density decreases due to the size of the particle size. Moreover, the space | gap part which can be formed in an adsorption tower increases, and the fall of cooling performance is considered. In such a type of heat exchanger, since the heat transfer surface is fins, it is necessary to increase the number of fins. Comes out. In dimensional design when cooling an adsorption tower using such a heat exchanger and an adsorbent, the adsorbent particle size has a certain size that can be mainly filled in the fin pitch of the heat exchanger. Therefore, the selection criteria for the adsorbent particle diameter are not clear (see, for example, Patent Document 2).

Japanese Patent Laid-Open No. 10-141803 (FIG. 8) Japanese Patent Application Laid-Open No. 11-241871

  In dimensional design when cooling an adsorption tower using a conventional heat exchanger and adsorbent, the adsorbent particle size has a certain size that can be filled into the fin pitch of the heat exchanger. Since the selection criteria for the adsorbent particle diameter were not clear, the adsorbing tower of the gasoline vapor recovery device had a problem of poor energy efficiency.

  This invention has been made to solve the above-described problems, and by grasping the difference in cooling performance caused by different combinations of heat exchanger fins and adsorbent particle sizes, which are constituent elements of the adsorption tower. Gasoline with efficient selection and effective heat exchanger fin pitch and adsorbent particle size as well as a clear selection by deriving optimum range and selection criteria for each dimension combination An adsorption tower for a vapor apparatus is provided.

  The adsorption tower of the gasoline vapor device according to the present invention includes a heat source unit, a gasoline condensing unit, and a brine condensing unit, and the heat source unit is composed of a refrigerant circulation circuit of a compressor, a condenser, a throttle device, and an evaporator, The condensing unit is composed of a gasoline refueling nozzle, a gasoline suction pump, and a gasoline vapor condensing pipe, and the brine condensing unit is a brine tank having an evaporator and a gasoline vapor condensing pipe, a brine pump, and a heat medium flow provided in the adsorption tower. In the gasoline vapor recovery apparatus composed of an adsorption tower vessel, an adsorbent, a heat medium flow pipe and a plate fin, the adsorption tower is composed of a fin and a fin of the fin heat exchanger. A particulate adsorbent is filled in between.

  Moreover, the ratio (F / D) of the fin pitch F which is the space | interval of the fin of a heat exchanger, and the particle diameter D of an adsorbent exists in the range of 4-6.

  In addition, the fin-type heat exchanger was arranged in parallel at a constant interval with a heat medium flow pipe composed of a plurality of U-shaped heat transfer pipes having two straight pipe parts and a hairpin part connecting the straight pipe parts. It is composed of a plurality of fins, and the straight pipe portion penetrates the fins vertically, and the row direction and the step direction penetrate at equal intervals respectively, the row direction pitch is 22 [mm], the step direction pitch Is 25.4 [mm], the heat transfer tube outer diameter is 9.52 [mm], and silica gel is packed between the fins as an adsorbent.

  According to the present invention, a heat exchanger for refrigeration and air conditioning that is generally used is filled with a granular adsorbent between fins, and the optimum combination of dimensions is confirmed by a test. By diverting a heat exchanger for air conditioning or a heat exchanger used in a refrigerator, there is an advantage that the manufacturing cost can be greatly reduced. By selecting the ratio (F / D) of the fin pitch F to the adsorbent particle diameter D within the range of 4 to 6, the heat transfer from the heat exchanger can be conducted most efficiently. Thus, the energy efficiency of the adsorption tower can be improved.

Embodiment 1 FIG.
FIG. 1 is an overall configuration diagram of a gasoline vapor recovery device according to Embodiment 1 of the present invention. In FIG. 1, this gasoline vapor recovery device is composed of a heat source unit 1, a gasoline condensing unit 2, and an antifreeze (brine) condensing unit 3. The heat source unit 1 includes a refrigerant circulation circuit including a compressor 5, a condenser 6, an expansion device 7, and an evaporator 8. Note that a refrigerant flows in the refrigerant circuit, and a nonflammable HFC refrigerant or a natural refrigerant (for example, CO 2) is used as the refrigerant. The gasoline condensing unit 2 includes a gasoline refueling nozzle 9, a gasoline suction pump 10, and a gasoline vapor condensing pipe 12. The brine condensing unit 3 includes a brine tank 11 having a refrigerant circuit evaporator 8 and a gasoline vapor condensing pipe 12, a brine pump 13, and a heat medium circulation pipe 16 in the adsorption tower 4. The adsorption tower 4 includes an adsorption tower container 14, an adsorbent 15, a heat medium flow pipe 16, and a plate fin 17.

  Next, the operation of the gasoline vapor recovery device in the first embodiment will be described. The temperature of the evaporator 8 is lowered by operating the equipment in the refrigerant circuit by the heat source unit 1. The brine is cooled to a constant temperature by the cooling of the evaporator 8, and the operation of the equipment in the refrigerant circuit is stopped and controlled at a constant temperature. Gasoline is supplied from the gasoline refueling nozzle 9, and at that time, gasoline vapor discharged from the inside of a gasoline tank of an automobile or the like is sucked by the gasoline suction pump 10 and gradually cooled by passing through the gasoline condensing pipe 12. Vapor becomes gasoline liquid. The gasoline vapor liquefied and recovered to about 10 [vol%] through the gasoline condensing pipe 12 while being sucked by the gasoline suction pump 10 is transported to the adsorption tower 4. The remaining gasoline vapor that has flowed into the adsorption tower 4 is adsorbed by the adsorbent 15 in the adsorption tower container 14, and is released into the atmosphere at less than 1 [vol%]. Further, the adsorbent 15 is cooled by a brine flowing in the heat medium flow pipe 16 in the adsorption tower 4, and the brine is circulated through the brine tank 11 and the heat medium flow pipe 16 by the brine pump 13 and controlled at a constant temperature. ing.

Next, the structure of the adsorption tower 4 in this Embodiment 1 is demonstrated. FIG. 2 is an enlarged configuration diagram showing the upper cross section of the adsorption tower and the internal details of the adsorption tower of the gasoline vapor recovery apparatus according to Embodiment 1 of the present invention. As shown in FIG. 3, the heat exchanger accommodated in the adsorption tower 4 is a general structure in which plate fins 17 provided perpendicular to the outer surface of the heat medium flow pipe (copper pipe) 16 are configured as heat transfer surfaces. It is a heat exchanger for refrigeration and air conditioning used in And the general heat exchanger comprised in this way is stored in the adsorption tower container 14. FIG. The adsorption tower 4 is configured by filling the adsorbent 15 between the fins 17 of the heat exchanger 17 and the fins 17 (fin pitch) and in the gap of the adsorption tower container 14. An antifreeze liquid (brine) or HFC refrigerant maintained at a low temperature is introduced into the heat medium flow pipe 16 of the heat exchanger from the lower part of the adsorption tower 4, and the adsorbent 15 by heat conduction through the plate fins 17 (material: aluminum). Is cooled. In the gasoline vapor recovery apparatus in the first embodiment, the cooled brine in the brine tank 11 is introduced into the heat medium circulation pipe 16 by the brine pump 13 and circulated to maintain the low temperature. In the first embodiment, a heat exchanger is used as a method for cooling the adsorbent 15. However, as another cooling method, a method for cooling the entire adsorption tower container 14, a coiled pipe in the adsorption tower 4, or the like. A cooling method by flowing cooling water into the water can be considered. However, in the first embodiment, by diverting the heat exchanger used for refrigeration and air conditioning, it is possible to use an excellent cooling performance and a significantly low manufacturing cost. Decided to apply. Further, the heat exchanger for refrigeration and air-conditioning that is generally used includes several types of fin shapes such as ring fins and rubastair fins. In the first embodiment, the adsorbent 15 is used as a heat exchanger. Since it is necessary to efficiently fill the space between the fins 17 and 17 (fin pitch), it is necessary that the fins have a flat shape that does not have a shape that can be filled or cut and raised. Furthermore, in the case of a heat exchanger for refrigeration and air conditioning, the fin pitch is generally in the range of 1.5 to 10 mm due to restrictions such as air path resistance and frosting. When this heat exchanger for refrigeration and air conditioning is used for the adsorption tower 4, generally, the smaller the fin pitch, the larger the heat transfer area, so that the amount of heat existing in the adsorption tower 4 is more easily transferred to the heat medium flow pipe 16. It is considered to be. However, as the fin pitch becomes smaller, it becomes difficult to fill the adsorbent 15, the packing density decreases, and cooling performance and adsorption performance can be reduced. It is also conceivable that if the fin pitch is too large, the adsorbent 15 is not sufficiently cooled. Therefore, as shown in the image diagram of FIG. 6, the heat exchanger fin pitch F and the combination of the adsorbent particle diameters D, that is, the value of (fin pitch F) / (adsorbent particle diameter D) It is considered that there exists a combination of dimensions having the best cooling performance, such as the x portion, which is the intersection of the efficiency of transferring the heat of the pitch F and the adsorbent particle diameter D. Therefore, in Embodiment 1 of the present invention, by combining the fin pitch F of the plate fin heat exchanger used in the adsorption tower 4 and the particle size D of the adsorbent, the cooling performance is most excellent. Study was carried out.
Table 1 shows combinations of heat exchanger fin pitch F and adsorbent particle size D. In addition, the adsorbent 15 used at this time uses particulate silica gel as an adsorbent for gasoline vapor, and for the convenience of commercially available adsorbent particle size, the adsorbent 15 is limited to the following combinations. However, the present embodiment is not limited to these. Furthermore, also for the heat exchanger, a heat exchanger having a fin pitch determined to be able to be filled with the adsorbent in the first embodiment of the present invention is used. The heat exchanger has a step pitch of 25.4 mm, a row pitch of 22 mm, and a heat transfer tube outer diameter of 9.5 mm.

The number average particle size is used as the particle size in the first embodiment.
Heat was exchanged by allowing brine to flow into the heat exchanger from the lower part of the adsorption tower 4. The brine has a flow rate of about 6 to 7 [l / min] by the brine pump 13, and the inlet temperature of the adsorption tower of the brine is maintained at a low temperature by a cooler (evaporator 8 of the brine tank 11). Therefore, the brine flows into the adsorption tower 4 through the brine pump 13, receives the amount of heat existing in the adsorption tower, and returns to the cooler (evaporator 8 in the brine tank 11), thereby cooling the adsorbent 15. Done.

The operation of the first embodiment of the present invention will be described below.
By using a cooler (evaporator 8 in the brine tank 11), the inlet temperature of the brine in the adsorption tower is controlled to about 1 [° C.] and flows from the lower part of the adsorption tower 4 to cool the adsorption tower 4 from the room temperature. The temperature change over time was examined.
The amount of heat in the adsorption tower is carried out of the adsorption tower by the brine through the heat exchanger fins. The following equation 1 can be considered for the heat balance in the adsorption tower.

[Formula 1]

In this case, the heat release from the adsorption tower vessel was ignored.
When Expression 1 is integrated, the following Expression 2 is obtained.

[Formula 2]

  FIG. 5 shows the results when the heat exchanger fin pitch Fp = 3.0 [mm] and the adsorbent particle diameter Dp = 0.5 to 0.84 [mm] are applied to the above equation. The vertical axis represents the left side, and the horizontal axis represents the right side. From Fig. 5, this equation can be approximated to a linear function, and becomes the following equation 3.

[Formula 3]

  Thus, by multiplying the specific heat of the adsorbent packed in the gradient (absolute value) of this function and the packed weight in the adsorption tower, the ease of temperature transfer from the adsorbent to the heat exchanger (cooling performance) is expressed. 4 can be calculated.

[Formula 4]

  FIG. 7 shows the difference in cooling performance when a cooling test is performed with a combination of each adsorbent particle diameter D and heat exchanger fin pitch F in the present invention. This indicates the ratio of the amount of heat that the adsorbent 15 is transmitted to the brine flowing through the heat medium flow pipe 16 through the fins of the heat exchanger on the vertical axis. The horizontal axis is the value (F / D) divided by the number average particle diameter (D) of the adsorbent 15 filled with the fin pitch (F) of the heat exchanger. By making it dimensionless, the cooling performance of each combination is shown. This makes comparison easier. According to FIG. 7, if the fin pitch F and the particle diameter D are selected within the range of F / D = 4-6, the heat transfer performance can be doubled, so the time required for cooling is short. I can do it.

As described above, generally, the adsorbent has a characteristic that the amount of adsorption increases as the temperature is lowered. Therefore, the adsorption tower 4 is provided with a heat exchanger as in the first embodiment to cool the adsorbent so that the adsorption performance can be maximized in order to use this characteristic of the adsorbent. . Moreover, as shown in the image diagram of FIG. 6, according to FIG. 7, there is a portion (× portion) that is an intersection of the efficiency of transferring heat of both the fin pitch and the adsorbent particle size at F / D = 4 to 6, It can be confirmed that the combination of dimensions has the most cooling performance.
Immediately after the start of operation of the adsorption tower, the adsorbent is at ambient temperature, and the adsorbent must be cooled from that state to a predetermined temperature. During the cooling time to the predetermined temperature, the gas containing the adsorbate cannot be sent to the adsorption tower, and thus energy is wasted. That is, in order to improve the energy efficiency of the adsorption tower, it is necessary to increase the cooling rate until reaching a predetermined temperature. By setting the fin pitch F and the adsorbent particle size D in the range of F / D = 4 to 6 as in the present invention, it becomes possible to significantly reduce the cooling time as shown in FIG. The energy efficiency of the adsorption tower can be improved.

It is a whole lineblock diagram of a gasoline vapor recovery device in Embodiment 1 of this invention. It is a block diagram which expands and shows the upper cross section of the adsorption tower of the gasoline vapor recovery apparatus in Embodiment 1 of this invention, and the internal details of an adsorption tower. It is a three-dimensional image figure (part) of the heat exchanger structure in an adsorption tower by Embodiment 1 of this invention. It is a characteristic view which shows the cumulative existence rate of the particle | grain mass reference | standard of the adsorbent used in Embodiment 1 of this invention. It is a characteristic view which shows the time change of the logarithm value of the difference of the adsorption tower internal temperature at the time of cooling the adsorption tower used in Embodiment 1 of this invention, and a brine inlet_port | entrance temperature. It is an image figure which shows how heat of fin pitch and adsorbent particle diameter is transmitted. It is a characteristic view which shows the difference by the fin pitch / adsorbent particle size of cooling performance in Embodiment 1 of this invention. It is an image figure which shows the difference of the temperature time change in an adsorption tower at the time of optimizing the heat exchanger fin pitch of an adsorption tower, and an adsorbent particle size.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heat source unit 7 Expander 13 Brine pump 2 Gasoline condensing unit 8 Evaporator 14 Adsorption tower container 3 Brine unit 9 Gasoline refueling nozzle 15 Adsorbent 4 Adsorption tower 10 Gasoline suction pump 16 Heating medium distribution pipe 5 Compressor 11 Brine tank 17 Plate Fin 6 Condenser 12 Gasoline vapor condensing pipe

Claims (4)

Equipped with heat source unit, gasoline condensing unit, brine condensing unit,
The heat source unit includes a refrigerant circulation circuit of a compressor, a condenser, a throttle device, and an evaporator,
The gasoline condensing unit is composed of a gasoline refueling nozzle, a gasoline suction pump, a gasoline vapor condensing pipe,
The brine condensing unit is composed of a brine tank having the evaporator and the gasoline vapor condensing pipe, a brine pump, and a heat medium flow pipe provided in the adsorption tower,
The adsorption tower comprises an adsorption tower container, an adsorbent, the heat medium flow pipe and a fin-type heat exchanger having a plate fin, and a gasoline vapor recovery apparatus,
An adsorption tower for a gasoline vapor recovery apparatus, wherein a particulate adsorbent is filled between fins of the fin-type heat exchanger.   The gasoline vapor according to claim 1, wherein the ratio (F / D) of the fin pitch F, which is the distance between the fins of the heat exchanger, and the particle diameter D of the adsorbent is in the range of 4-6. Adsorption tower of the recovery device.   The fin-type heat exchanger includes a plurality of U-shaped heat transfer tubes having two straight tube portions and a hairpin portion connecting the straight tube portions, and a plurality of heat medium flow tubes arranged in parallel at regular intervals. The straight pipe portion penetrates the fin vertically, the row direction and the step direction penetrate at equal intervals, and silica gel is filled as an adsorbent between the fins. The adsorption tower of the gasoline vapor recovery apparatus according to claim 1 or 2.   4. The gasoline vapor according to claim 3, wherein the fin-type heat exchanger has a pitch in the row direction of 22 [mm], a pitch in the step direction of 25.4 [mm], and an outer diameter of the heat transfer tube of 9.52 [mm]. Adsorption tower of the recovery device.

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