JP2017144414A - Canister and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a canister excellent in VOC desorption performance in a small purge gas amount.SOLUTION: A canister 10 includes a container 11, and a carbon porous body stored in the container 11. In the carbon porous body, a nitrogen adsorption amount is 1,500 cm(STP)/g when a nitrogen relative pressure P/Pis 0.99, in a nitrogen adsorption isotherm measured at a temperature of 77K.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a canister.

  Most of the automatic propulsion vehicles that use the power generated by the combustion engine as a propulsive force use liquid fuel such as gasoline or light oil as the fuel. This liquid fuel contains a volatile organic compound (hereinafter referred to as VOC). Therefore, VOC volatilizes in the fuel tank during the stop period when the combustion engine is stopped. VOC vaporization can increase the internal pressure of the fuel tank.

  In an automobile having an internal combustion engine, vaporized VOC is collected in a canister in which an adsorbent is accommodated in a sealed container. Specifically, the vaporized VOC is adsorbed on an adsorbent made of activated carbon by connecting the inside of the sealed container and the upper space in the fuel tank during the stop period. In addition, when activated carbon adsorbs VOC, the adsorptive power decreases according to the amount of adsorption. Therefore, in an automobile equipped with a canister, air is circulated as a purge gas through the adsorbent layer and VOC is desorbed from the activated carbon during an operation period in which the internal combustion engine is operating. Further, the gas exhausted from the canister is burned by the internal combustion engine.

  The canister is required that the activated carbon adsorbs a sufficient amount of VOC during the stop period and that most of the adsorbed VOC is desorbed from the activated carbon during the operation period. According to the evaporative fuel processing apparatus described in Patent Document 1 and the canister described in Patent Document 2, a sufficient VOC adsorption amount and desorption amount can be achieved.

JP 2012-31785 A JP 2008-38688 A

However, the present inventors consider that there is room for improvement in VOC desorption performance when the amount of purge gas in the canister is small.
Accordingly, an object of the present invention is to provide a canister having excellent VOC desorption performance with a small purge gas amount.

According to the first aspect of the present invention, a container and a carbon porous body accommodated in the container are provided, and the carbon porous body has a nitrogen relative pressure P / P ₀ of 0 in a nitrogen adsorption isotherm measured at a temperature of 77K. A canister having a nitrogen adsorption amount at .99 of 1500 cm ³ (STP) / g or more is provided.

  According to the second aspect of the present invention, an alkaline earth metal salt of benzenedicarboxylic acid is heated at a temperature in the range of 550 ° C. to 700 ° C. in an inert atmosphere in the presence of a trap material that adsorbs hydrocarbon gas. Forming a composite of carbon and alkaline earth metal carbonate, washing the composite with a cleaning solution capable of dissolving the carbonate, and removing the carbonate from the composite. A method of manufacturing a canister is provided that includes a step of obtaining a carbon porous body.

  According to the present invention, a canister excellent in VOC desorption performance with a small purge gas amount is provided.

1 is a perspective view schematically showing a canister according to one embodiment of the present invention. Sectional drawing along the II-II line of the canister shown in FIG. The graph which shows an example of the adsorption isotherm which belongs to IV type by IUPAC classification. Sectional drawing which shows schematically the other example of the structure employable for the canister shown in FIG.1 and FIG.2. Sectional drawing which shows schematically the further another example of the structure employable for the canister shown in FIG.1 and FIG.2. The graph which shows an example of the relationship between the nitrogen adsorption amount and the pentane desorption rate when the nitrogen relative pressure P / P ₀ is 0.99 in the nitrogen adsorption isotherm measured at a temperature of 77K.

Hereinafter, embodiments of the present invention will be described.
FIG. 1 is a perspective view schematically showing a canister according to an aspect of the present invention. 2 is a cross-sectional view taken along the line II-II of the canister shown in FIG.

  The canister 10 includes a container 11 whose inner surface is insulating. The container 11 is a sealed container provided with an air supply port and an exhaust port, for example.

  Here, as an example, a first air supply port IP1 for supplying a gas containing VOC into the container 11 and a second air supply for supplying a purge gas into the container 11 to the upper plate portion of the container 11. The port IP2 and an exhaust port OP for exhausting the purge gas in the container 11 are provided. The purge gas is a gas having a lower VOC concentration than the gas supplied from the first air supply port IP1 into the container 11 such as air.

  Here, as an example, the container 11 is provided with a partition plate PP extending from the upper plate portion toward the bottom plate portion between the second air supply port IP2 and the exhaust port OP. The partition plate PP divides the upper space in the container 11 into a front chamber in which the second air supply port IP2 communicates and a rear chamber in which the first air supply port IP1 and the exhaust port OP communicate with each other.

  A porous plate 12 made of an insulator is installed near the bottom in the container 11. The porous plate 12 is separated from the bottom plate portion of the container 11. Typically, the porous plate 12 is installed so that the upper surface thereof is in contact with the partition plate PP. In this way, the communication between the previous front chamber and the rear chamber is made only through the lower space between the bottom plate portion of the container 11 and the porous plate 12. Note that the porous plate 12 is not necessarily provided.

An adsorbent layer 14 made of an adsorbent 13 is provided in the container 11 and above the porous plate 12. When the partition plate PP is installed, the adsorbent layer 14 has a thickness that embeds the end portion of the partition plate PP on the porous plate 12 side.
The adsorbent 13 is composed of a carbon porous body and a binder obtained by bonding them together.

The nitrogen adsorption amount A3 of this carbon porous body is 1500 cm ³ (STP) / g or more, typically 1600 cm ³ (STP) / g or more, preferably 1700 cm ³ (STP) / g or more. More preferably, it is 1800 cm ³ (STP) / g or more. The nitrogen adsorption amount A3 has no upper limit, but is, for example, 2500 cm ³ (STP) / g or less, and typically 2000 cm ³ (STP) / g or less. A carbon porous body having a large nitrogen adsorption amount A3 tends to have high VOC desorption performance. STP (Standard Temperature and Pressure) represents 0 ° C. and 10 ⁵ Pa. Here, the nitrogen adsorption amount A3 means the nitrogen adsorption amount when the nitrogen relative pressure P / P ₀ is 0.99 in the nitrogen adsorption isotherm measured at a temperature of 77K.

This nitrogen adsorption isotherm can be determined as follows. First, the nitrogen gas adsorption amount (mL / mL) of the carbon porous body is measured for each pressure P while gradually increasing the pressure P (mmHg) of the nitrogen gas in 77K (nitrogen boiling point) nitrogen gas. . Next, the value obtained by dividing the pressure P (mmHg) by the saturated vapor pressure P ₀ (mmHg) of nitrogen gas is taken as the relative pressure P / P ₀ , and the adsorption amount is plotted by plotting the nitrogen gas adsorption amount with respect to each relative pressure P / P ₀ . An isotherm can be obtained.

  FIG. 3 is a graph showing an example of the nitrogen adsorption isotherm thus obtained. The nitrogen adsorption isotherm shown in FIG. 3 belongs to type IV in the IUPAC classification. In the nitrogen adsorption isotherm belonging to type IV in the IUPAC classification, the nitrogen adsorption amount when the pressure is increased does not match the nitrogen adsorption amount when the pressure is decreased in a specific relative pressure range. Such a nitrogen adsorption isotherm indicates the possibility that pores having a diameter of more than 2 nm and not more than 50 nm, that is, mesopores, exist in the carbon porous body.

Nitrogen adsorption A4 of the carbon porous body, for example, in the range of 800cm ³ (STP) / g to 1500cm ³ (STP) / g, preferably, 1000cm ³ (STP) / g to 1300 cm ³ (STP) / g Yes within the range of, more preferably, in the range of 1100 cm ³ (STP) / g to 1300cm ³ (STP) / g. The carbon porous body having the nitrogen adsorption amount A4 within this range tends to have higher VOC desorption performance than other carbon porous bodies. Here, the nitrogen adsorption amount A4 means the nitrogen adsorption amount when the nitrogen relative pressure P / P ₀ is 0.9 in the nitrogen adsorption isotherm measured at the temperature of 77K.

Nitrogen adsorption amount A2 of the carbon porous body, for example, in the range of 600cm ³ (STP) / g to 1100cm ³ (STP) / g, typically, 800cm ³ (STP) / g to 1100 cm ³ ( STP) / g, preferably 900 cm ³ (STP) / g to 1000 cm ³ (STP) / g. The carbon porous body having the nitrogen adsorption amount A2 within this range tends to have higher VOC desorption performance than other carbon porous bodies. Here, the nitrogen adsorption amount A2 means the nitrogen adsorption amount when the nitrogen relative pressure P / P ₀ is 0.85 in the nitrogen adsorption isotherm measured at the temperature of 77K.

The nitrogen adsorption amount A1 of the carbon porous body is, for example, 500 cm ³ (STP) / g or less, and typically 400 cm ³ (STP) / g or less. The nitrogen adsorption amount A1 has no lower limit, but is, for example, 50 cm ³ (STP) / g or more, and typically 100 cm ³ (STP) / g or more. A carbon porous body with a small nitrogen adsorption amount A1 tends to have higher VOC desorption performance than other carbon porous bodies. Here, the nitrogen adsorption amount A1 means the nitrogen adsorption amount when the nitrogen relative pressure P / P ₀ is 0.5 in the nitrogen adsorption isotherm measured at the temperature of 77K.

The micropore volume of this carbon porous body is, for example, 0.1 cm ³ / g or less, and typically 0.01 cm ³ / g or less. Although no lower limit to the volume of the micropores, for example, at 0.001 cm ³ / g or more, and is typically 0.005 cm ³ / g or more. Here, the micropore volume means the volume of a pore having a diameter of 2 nm or less. A carbon porous body having a small micropore volume tends to have a higher VOC desorption performance than other carbon porous bodies.

The micropore volume can be obtained by performing an α _s plot analysis on the nitrogen adsorption isotherm measured at the temperature of 77K. In the α _s plot analysis, “Characterization of porous carbons with high resolution alpha (s) -analysis and low temperature magnetic susceptibility” Kaneko, K; Ishii, C; Kanoh, H; Hanazawa, Y; Standard isotherm described in Setoyama, N; Suzuki, T ADVANCES IN COLLOID AND INTERFACE SCIENCE vol.76, p295-320 (1998) is used.

The nitrogen adsorption amount difference ΔA3-A4 of the carbon porous body is, for example, 300 cm ³ (STP) / g or more, typically 400 cm ³ (STP) / g or more, and preferably 500 cm ³ (STP). / G or more. The nitrogen adsorption amount difference ΔA3-A4 has no upper limit value, but is, for example, 1300 cm ³ (STP) / g or less, and typically 1000 cm ³ (STP) / g or less. A carbon porous body with a large difference in nitrogen adsorption amount ΔA3-A4 tends to have higher VOC desorption performance than other carbon porous bodies. Here, the difference in nitrogen adsorption amount ΔA3−A4 is calculated from the nitrogen adsorption amount A3 when the nitrogen relative pressure P / P ₀ is 0.99 in the nitrogen adsorption isotherm measured at the temperature of 77K. It means a value obtained by subtracting the nitrogen adsorption amount A4 when P ₀ is 0.9.

The nitrogen adsorption amount difference ΔA3-A2 of the carbon porous body is, for example, 500 cm ³ (STP) / g or more, and typically 700 cm ³ (STP) / g or more. The nitrogen adsorption amount difference ΔA3-A2 has no upper limit, but is, for example, 1300 cm ³ (STP) / g or less, and typically 1000 cm ³ (STP) / g or less. A carbon porous body having a large nitrogen adsorption amount difference ΔA3-A2 tends to have a higher VOC desorption performance than other carbon porous bodies. Here, the difference in nitrogen adsorption amount ΔA3−A2 is calculated from the nitrogen adsorption amount A3 when the nitrogen relative pressure P / P ₀ is 0.99 in the nitrogen adsorption isotherm measured at the temperature of 77K. It means a value obtained by subtracting the nitrogen adsorption amount A2 when P ₀ is 0.85.

Nitrogen adsorption amount difference ΔA3-A1 of the carbon porous body, for example, a 1000cm ³ (STP) / g or more, will typically be at 1200cm ³ (STP) / g or more, preferably, 1400 cm ³ (STP ) / G or more. The nitrogen adsorption amount difference ΔA3-A1 has no upper limit value, but is, for example, 1800 cm ³ (STP) / g or less, and typically 1500 cm ³ (STP) / g or less. A carbon porous body having a large nitrogen adsorption amount difference ΔA3-A1 tends to have higher VOC desorption performance than other carbon porous bodies. Here, the nitrogen adsorption amount difference ΔA3−A1 is calculated from the nitrogen adsorption amount A3 when the nitrogen relative pressure P / P ₀ is 0.99 in the nitrogen adsorption isotherm measured at the temperature of 77K. It means a value obtained by subtracting the nitrogen adsorption amount A1 when P ₀ is 0.5.

The nitrogen adsorption amount difference ΔA4-A2 of the carbon porous body is, for example, 150 cm ³ (STP) / g or more, typically 200 cm ³ (STP) / g or more, and preferably 250 cm ³ (STP). ) / G or more. The nitrogen adsorption amount difference ΔA4-A2 has no upper limit, but is, for example, 400 cm ³ (STP) / g or less, and typically 300 cm ³ (STP) / g or less. A carbon porous body having a large difference in nitrogen adsorption amount ΔA4-A2 tends to have higher VOC desorption performance than other carbon porous bodies. Here, the difference in nitrogen adsorption amount ΔA4−A2 is determined from the nitrogen adsorption amount A4 when the nitrogen relative pressure P / P ₀ is 0.9 in the nitrogen adsorption isotherm measured at the above temperature of 77K, and the nitrogen relative pressure P / It means a value obtained by subtracting the nitrogen adsorption amount A2 when P ₀ is 0.85.

The nitrogen adsorption amount difference ΔA4-A1 of the carbon porous body is, for example, 500 cm ³ (STP) / g or more, typically 700 cm ³ (STP) / g or more, preferably 800 cm ³ (STP). / G or more. The nitrogen adsorption amount difference ΔA4-A1 has no upper limit, but is, for example, 1200 cm ³ (STP) / g or less, and typically 1000 cm ³ (STP) / g or less. A carbon porous body having a large difference in nitrogen adsorption amount ΔA4-A1 tends to have a higher VOC desorption performance than other carbon porous bodies. Here, the difference in nitrogen adsorption amount ΔA4-A1 is determined from the nitrogen adsorption amount A4 when the nitrogen relative pressure P / P ₀ is 0.9 in the nitrogen adsorption isotherm measured at the temperature of 77K, and the nitrogen relative pressure P / It means a value obtained by subtracting the nitrogen adsorption amount A1 when P ₀ is 0.5.

Nitrogen adsorption amount difference ΔA of the carbon porous body, for example, a 100cm ³ (STP) / g or more, will typically be in 300cm ³ (STP) / g or more, preferably, 500cm ³ (STP) / g or more, more preferably 600 cm ³ (STP) / g or more. The nitrogen adsorption amount difference ΔA has no upper limit, but is, for example, 1200 cm ³ (STP) / g or less, and typically 1000 cm ³ (STP) / g or less. A carbon porous body having a large difference in nitrogen adsorption amount ΔA tends to have higher VOC desorption performance than other carbon porous bodies. Here, the nitrogen adsorption amount difference ΔA is the nitrogen adsorption isotherm was measured at the stated temperature 77K, the nitrogen adsorption amount A2 at a nitrogen relative pressure P / P ₀ of 0.85, a nitrogen relative pressure P / P ₀ Is a value obtained by subtracting the nitrogen adsorption amount A1 when 0.5 is 0.5.

The specific surface area of this carbon porous body is, for example, 700 m ² / g or more, and typically 800 m ² / g or more. Here, the “specific surface area” means a specific surface area obtained by using a BET adsorption isotherm (Brunauer, Emmet and Teller's equation), that is, a BET specific surface area. In addition, although there is no upper limit in this specific surface area, it is 1400 m < ² > / g or less, for example, typically 1200 m < ² > / g or less, Preferably it is 1100 m < ² > / g or less.

Such a carbon porous body can be manufactured as follows, for example.
First, benzenedicarboxylic acid and an alkaline earth metal hydroxide are mixed and heated in a water bath at a temperature of 50 ° C. to 100 ° C. to produce an alkaline earth metal salt of benzenedicarboxylic acid. The product salt is then collected by filtration and dried at room temperature.

  The benzenedicarboxylic acid is, for example, phthalic acid (benzene-1,2-dicarboxylic acid), isophthalic acid (benzene-1,3-dicarboxylic acid), terephthalic acid (benzene-1,4-dicarboxylic acid) or a mixture thereof. Yes, preferably terephthalic acid.

  The alkaline earth metal is, for example, magnesium, calcium, strontium, barium or a mixture thereof, preferably calcium.

  The molar ratio of benzenedicarboxylic acid to alkaline earth metal hydroxide may be a stoichiometric ratio based on the neutralization reaction formula or may deviate from the stoichiometric ratio. This molar ratio is, for example, in the range of 1.5: 1 to 1: 1.5.

  In addition, although the alkaline-earth metal salt of benzenedicarboxylic acid may be obtained by the above method, a commercially available product may be used.

  Next, this produced salt is heated at a temperature of 550 ° C. to 700 ° C. in an inert atmosphere in the presence of a trapping material to form a composite of carbon and alkaline earth metal carbonate. This composite is presumed to have a structure in which an alkaline earth metal carbonate enters between layers of layered carbides. As will be described later, by removing alkaline earth metal carbonate from this composite, the above-described porous carbon body can be obtained.

  The trap material adsorbs (adsorbs and removes) hydrocarbon gas. When a trapping material is allowed to coexist when heating the alkaline earth metal salt of benzenedicarboxylic acid, the concentration of the hydrocarbon gas generated when the alkaline earth metal salt of benzenedicarboxylic acid is heated is determined as described above for the carbon porous body. It is easy to make it a suitable range in achieving the hole portion. The trap material is, for example, one or more selected from the group consisting of activated carbon, silica gel, zeolite, and diatomaceous earth, and is preferably activated carbon.

  The trap material may be mixed with an alkaline earth metal salt of benzenedicarboxylic acid. The trap material may be formed in a filter shape and placed above the alkaline earth metal salt of benzenedicarboxylic acid. Alternatively, a part of the trapping material may be mixed with an alkaline earth metal salt of benzenedicarboxylic acid, and the remaining trapping material may be formed in a filter shape and placed above the alkaline earth metal salt of benzenedicarboxylic acid. Examples of the trap material formed in a filter shape include a trap material formed into a honeycomb shape, a trap material supported on a ceramic or metal honeycomb carrier, and a trap material sandwiched between a plurality of metal mesh materials. Can be mentioned.

  The amount of the trap material is preferably in the range of 100 to 1000 parts by mass, more preferably in the range of 200 to 300 parts by mass with respect to 100 parts by mass of benzenedicarboxylic acid.

The heating temperature is preferably in the range of 550 ° C to 700 ° C. When the heating temperature is low, in the obtained carbon porous body, the nitrogen adsorption amount A3 when the nitrogen relative pressure P / P ₀ of the nitrogen adsorption isotherm at 77 K is 0.99 tends not to be sufficiently large. When the heating temperature is high, the carbon porous body tends not to be formed. The heating time is, for example, 50 hours or less, preferably 0.5 to 20 hours, and more preferably 1 to 10 hours. When the heating time is short, there is a tendency that a complex of carbon and alkaline earth metal carbonate is not sufficiently formed. When the heating time is long, a carbon porous body having a relatively large BET specific surface area tends not to be obtained. Examples of the inert atmosphere include a nitrogen atmosphere and an argon atmosphere.

Next, the composite is washed with a cleaning solution capable of dissolving carbonate, and the carbonate is removed from the composite to obtain a porous carbon body. By performing such cleaning, it is presumed that the place where the alkaline earth metal carbonate in the composite was present becomes a cavity.
When the alkaline earth metal carbonate is calcium carbonate, it is preferable to use an acidic aqueous solution such as water or hydrochloric acid as a cleaning liquid capable of dissolving the alkaline earth metal carbonate.

  Here, the adsorbent 13 may include two or more types of carbon porous bodies with different manufacturing methods. When the adsorbent 13 includes two or more types of carbon porous bodies with different production methods, the nitrogen adsorption isotherm of the carbon porous body included in the adsorbent 13 is obtained with two or more types of carbon porous bodies with different production methods. It is a nitrogen adsorption isotherm obtained by the above-mentioned method about this mixture. In addition, the nitrogen adsorption isotherm of the carbon porous body contained in the adsorbent 13 is a weighted average of each nitrogen adsorption isotherm obtained by the above-described method for each carbon porous body according to the mass ratio of each carbon porous body. Can also be obtained.

  The ratio of the carbon porous body to the total amount of the adsorbent 13 is, for example, in the range of 60% by mass to 90% by mass, and typically in the range of 70% by mass to 80% by mass.

  The binder is, for example, a cellulose material, a styrene butadiene rubber resin, a urethane resin, or a mixture thereof.

  The adsorbent 13 has, for example, a granular shape, a pellet shape, or a honeycomb shape. The average particle diameter of the adsorbent 13 is, for example, in the range of 0.1 mm to 10 mm. This average particle diameter can be determined according to a method for calculating an average particle diameter defined in Japanese Industrial Standard JIS K 1474: 2014 (7.5). The adsorbent 13 may be in a powder form. In this case, the adsorbent 13 may typically be supported on a substrate such as a honeycomb substrate or a porous substrate.

  The adsorbent layer 14 may include two or more types of adsorbents 13. FIG. 4 is a cross-sectional view schematically showing another example of a structure that can be employed in the canister shown in FIGS. 1 and 2. FIG. 5 is a cross-sectional view schematically showing still another example of a structure that can be employed in the canister shown in FIGS. 1 and 2. 4 and 5, the adsorbent layer 14 includes a first adsorbent 13a and a second adsorbent 13b.

  The 1st adsorption material 13a consists of a carbon porous body obtained by the manufacturing method mentioned above and a binder, for example. As the binder, for example, the same ones as mentioned for the adsorbent 13 can be used.

  The second adsorbent 13b is made of, for example, a carbon porous body and a binder obtained by a manufacturing method different from the carbon porous body constituting the first adsorbent 13a. Examples of such a carbon porous body include BAX-1500 (manufactured by MeadWestvaco Corp.). BAX-1500 is activated carbon that does not satisfy the above-described conditions. As the binder, for example, the same ones as mentioned for the adsorbent 13 can be used.

  A set of the carbon porous body included in the first adsorbent 13a and the carbon porous body included in the second adsorbent 13b satisfies the above-described conditions as a whole. As long as this aggregate satisfies the above-described conditions, only one of the first adsorbent 13a and the second adsorbent 13b may satisfy the above-described condition, or both may satisfy.

  As shown in FIG. 5, the first adsorbent 13a and the second adsorbent 13b may be mixed. Alternatively, the region made of the first adsorbent 13a and the region made of the second adsorbent 13b may be arranged in series along the purge gas path. In this case, as shown in FIG. 4, the area | region which consists of 2nd adsorption material 13b may be arrange | positioned in any one of a front chamber and a back chamber, and may be arrange | positioned in both.

  The canister 10 using the carbon porous body satisfying the above conditions as the adsorbing material is excellent in VOC desorption performance with a small purge gas amount. Therefore, this canister 10 can reduce the amount of the adsorbent 13 used as compared with a canister using a carbon porous body that does not satisfy the above-described conditions as an adsorbing material. Therefore, when this carbon porous body is used as the adsorbing material for the canister 10, the canister 10 can be reduced in size and the weight of the automatic propulsion vehicle on which the canister 10 is mounted can be realized.

The canister 10 described above can be variously modified.
For example, the canister 10 may include an electric heater (not shown). The electric heater may be installed in contact with the adsorbent layer 14 or may be embedded in the adsorbent layer 14. Alternatively, the electric heater may be installed on the outer periphery of the container 11. When supplying the purge gas into the container 11 from the second air supply port IP2, if the resistance heating element of the electric heater is energized, the temperature of the adsorbent layer 14 is prevented from lowering as the VOC is desorbed from the adsorbent 13. Can do.

  The canister 10 may include a pair of electrodes (not shown) instead of the electric heater. The pair of electrodes may be disposed on the inner wall of the container 11 or may be disposed on the main surface of the partition plate PP and on the inner wall of the container 11 facing the partition plate PP. Each of the pair of electrodes is connected to a terminal located outside the container 11. Each electrode includes a metal layer such as a metal plate or a metal foil. In such a canister 10, the adsorbent layer 14 can be used as a resistance heating element.

  Alternatively, the canister 10 may include a heat storage material (not shown). As a material of the heat storage material, for example, a metal material such as iron or copper, an inorganic material such as ceramic or glass, or a liquid material such as hexadecane can be used. The heat storage material may be in contact with the adsorbent layer 14 or may be embedded in the adsorbent layer 14. When the heat storage material is a liquid material, the heat storage material may be accommodated in a heat storage material container, and the heat storage material container may be installed in contact with the adsorbent layer 14 or embedded in the adsorbent layer 14. . As a material of the heat storage material container, for example, a material having higher thermal conductivity than the adsorbent 13 can be used. Alternatively, the wall of the container 11 may have a double structure, and a heat storage material may be accommodated between the outer wall and the inner wall.

When the adsorbent 13 adsorbs VOC, heat moves from the adsorbent 13 to the heat storage material. Further, when the adsorbent 13 desorbs the VOC, heat is transferred from the heat storage material to the adsorbent 13. Therefore, the heat storage material can suppress the temperature change of the adsorbent 13.
Alternatively, the canister 10 may include both an electric heater or an electrode and a heat storage material.

Examples of the present invention will be described below.
[Experimental Example 1]
(Creation of carbon porous body PC1)
First, terephthalic acid and calcium hydroxide were weighed at a molar ratio of 1: 1, and these were put into a reaction furnace together with water. The mixture was then reacted in a water bath heated to 80 ° C. to produce calcium terephthalate. Subsequently, this produced salt was separated by filtration. Next, the fractionated product salt and the same amount of the coconut shell activated carbon as the product salt are mixed, and the mixture is heat-treated at a temperature of 590 ° C. in an inert atmosphere to form a composite of carbide and calcium carbonate. Got. Next, the mixture of the composite and coconut shell activated carbon was dispersed in water, and hydrochloric acid was added dropwise to the dispersion to decompose calcium carbonate. Next, carbide and coconut shell activated carbon were separated from the dispersion by filtration, and the resulting mixture was dried. Next, the mixture was sieved to remove coconut shell activated carbon to obtain a carbide. The coconut shell activated carbon had sufficient dimensions to be filtered from the carbide. Hereinafter, this carbide is referred to as carbon porous body PC1.

(Creation of adsorbent AM1)
A mixture of 100 parts by mass of carbon porous body PC1 and 30 parts by mass of binder and water was sufficiently kneaded. Next, this mixture was molded into pellets by an extrusion molding method. The pellet had a circular shape with a diameter of 3 ± 1 mm and a height of 9 ± 3 mm. The pellet was then thoroughly dried. Hereinafter, this pellet is referred to as an adsorbent AM1.

(Creation of canister C1)
First, the resin container 11 described with reference to FIGS. 1 and 2 was prepared. In this container, the volume of the front chamber and the volume of the rear chamber were the same. Next, an equal amount of the adsorbent AM1 was filled in the front chamber and the rear chamber of the container to prepare a canister C1.

[Experiment 2]
Experimental Example 1 except that heat treatment was performed in the presence of 25 parts by mass of coconut shell activated carbon with respect to 100 parts by mass of the product salt instead of performing heat treatment in the presence of the same amount of coconut shell activated carbon as the generated salt. The porous carbon body PC2, the adsorbent AM2, and the canister C2 were obtained by the same method as described in the above.

[Experiment 3]
Except for changing the heat treatment temperature from 590 ° C. to 550 ° C., a carbon porous body PC3, an adsorbent AM3, and a canister C3 were obtained in the same manner as described in Experimental Example 1.

[Experimental Example 4]
In the heat treatment, carbon porous body PC4, adsorbent AM4 and canister C4 were obtained by the same method as described in Experimental Example 1 except that coconut shell activated carbon was not used.

[Experimental Example 5]
In the heat treatment, the carbon porous body PC5, the adsorbent AM5 and the canister C5 were prepared in the same manner as described in Experimental Example 1 except that the coconut shell activated carbon was not used and the heat treatment temperature was changed from 590 ° C. to 550 ° C. Obtained.

[Experimental Example 6]
A canister C6 was obtained in the same manner as described in Experimental Example 1 except that BAX-1500 (manufactured by MeadWestvaco Corp.) was used as the adsorbent AM6 instead of using the adsorbent AM1.

[Experimental Example 7]
As shown in FIG. 4, canister C7 was obtained by the same method as described in Experimental Example 1 except that a part of the adsorbent AM1 was replaced with the adsorbent AM6.
Specifically, first, the front chamber was filled with the same amount of adsorbent AM1 as in Experimental Example 1. Next, the adsorbent AM1 was filled in the rear chamber, and the adsorbent AM6 was filled on the area made of the adsorbent AM1. The mass ratio of the adsorbent AM1 and the adsorbent AM6 filled in the rear chamber was 16:34. The total amount of these adsorbents was the same as the amount of adsorbent AM1 filled in the front chamber.

[Experimental Example 8]
First, 66 parts by mass of the adsorbent AM1 and 34 parts by mass of the adsorbent AM6 were uniformly mixed to obtain a mixture. Next, canister C8 was obtained by the same method as described in Experimental Example 1 except that the above mixture was filled instead of filling adsorbent AM1.

[Experimental Example 9]
It was described in Experimental Example 1 except that the front chamber was filled with the adsorbent AM5 instead of the adsorbent AM1 and the rear chamber was filled with the adsorbent AM6 instead of the adsorbent AM1. The canister C9 was obtained by the same method.

[Experimental Example 10]
A canister C10 was obtained by the same method as described in Experimental Example 1 except that the adsorbent AM6 was filled instead of the adsorbent AM1 in the rear chamber.

[Characteristic value measurement]
(Measurement of nitrogen adsorption)
For the carbon porous bodies (activated carbon) used for the carbon porous bodies PC1 to PC5 and the adsorbent AM6, nitrogen adsorption isotherms were measured at a temperature of 77K. Specifically, first, each carbon porous body was set in a nitrogen adsorption amount measuring device (Quadrasorb SI: manufactured by Quantachrome Instruments). Next, nitrogen gas was adsorbed to each carbon porous body while changing the pressure at a temperature of minus 196 ° C., and the adsorption amount at each pressure was measured to obtain a nitrogen adsorption isotherm.

For each of Experimental Examples 7 to 10, the nitrogen adsorption isotherm of the carbon porous body obtained by the above measurement is weighted according to the mass ratio of the carbon porous body used in the experimental example, A nitrogen adsorption isotherm was calculated.
The results are shown in Table 1.

(Measurement of BET specific surface area)
A BET plot is calculated using the BET equation for the relative pressure in the nitrogen adsorption isotherm obtained by the above test in the range of 0.05 to 0.35, and the ratio according to each experimental example is calculated using this BET plot. The surface area was obtained. The BET multipoint method was used for calculating the BET plot.
The results are shown in Table 1.

In Table 1 above, among the columns below the heading “Nitrogen adsorption (cm ³ (STP) / g)”, the column labeled “A3 (P / P ₀ = 0.99)” contains the nitrogen In the nitrogen adsorption isotherm measured at a temperature of 77K obtained by the adsorption amount measurement, the nitrogen adsorption amount A3 when the nitrogen relative pressure P / P ₀ is 0.99 is described. In the column labeled “A4 (P / P ₀ = 0.90)”, the nitrogen relative pressure P / P ₀ is 0 on the nitrogen adsorption isotherm obtained by measuring the nitrogen adsorption amount and measured at a temperature of 77K. The nitrogen adsorption amount A4 when .90 is shown. In the column labeled “A2 (P / P ₀ = 0.85)”, the nitrogen relative pressure P / P ₀ is 0 on the nitrogen adsorption isotherm obtained by the nitrogen adsorption amount measurement and measured at a temperature of 77K. The nitrogen adsorption amount A2 when .85 is described. In the column labeled “A1 (P / P ₀ = 0.5)”, the nitrogen relative pressure P / P ₀ is 0 in the nitrogen adsorption isotherm obtained by measuring the nitrogen adsorption amount and measured at a temperature of 77K. The nitrogen adsorption amount A1 when .5 is shown.

In Table 1 above, among the columns below the heading “Nitrogen adsorption amount difference (cm ³ (STP) / g)”, the column labeled “ΔA3-A4” has nitrogen adsorption measured at a temperature of 77K. In the isotherm, the difference in nitrogen adsorption amount obtained by subtracting the nitrogen adsorption amount A4 when the nitrogen relative pressure P / P ₀ is 0.90 from the nitrogen adsorption amount A3 when the nitrogen relative pressure P / P ₀ is 0.99. It is described. The column denoted by "ΔA3-A2", the nitrogen adsorption isotherm was measured at a temperature 77K, the nitrogen adsorption amount A3 at a nitrogen relative pressure P / P ₀ of 0.99, a nitrogen relative pressure P / P ₀ The nitrogen adsorption amount difference obtained by subtracting the nitrogen adsorption amount A2 when is 0.85 is described. The column denoted by "ΔA3-A1", in a nitrogen adsorption isotherm was measured at a temperature 77K, the nitrogen adsorption amount A3 at a nitrogen relative pressure P / P ₀ of 0.99, a nitrogen relative pressure P / P ₀ The nitrogen adsorption amount difference obtained by subtracting the nitrogen adsorption amount A1 when is 0.5 is described. The column denoted by "ΔA4-A2", the nitrogen adsorption isotherm was measured at a temperature 77K, the amount of nitrogen adsorbed A4 at a nitrogen relative pressure P / P ₀ of 0.90, a nitrogen relative pressure P / P ₀ The nitrogen adsorption amount difference obtained by subtracting the nitrogen adsorption amount A2 when is 0.85 is described. The column denoted by "ΔA4-A1", in a nitrogen adsorption isotherm was measured at a temperature 77K, the amount of nitrogen adsorbed A4 at a nitrogen relative pressure P / P ₀ of 0.90, a nitrogen relative pressure P / P ₀ The nitrogen adsorption amount difference obtained by subtracting the nitrogen adsorption amount A1 when is 0.5 is described. In the column labeled “ΔA”, in the nitrogen adsorption isotherm measured at a temperature of 77K, the nitrogen relative pressure P / P ₀ is 0 from the nitrogen adsorption amount A2 when the nitrogen relative pressure P / P ₀ is 0.85. The nitrogen adsorption amount difference obtained by subtracting the nitrogen adsorption amount A1 at .5 is described.

Further, in Table 1 above, the column labeled “BET specific surface area (m ² / g)” describes the BET specific surface area obtained by the BET specific surface area measurement.

  As shown in Table 1, the nitrogen adsorption amount A3 of the carbon porous bodies PC1 to PC3 obtained by heat treatment in the presence of coconut shell activated carbon is the carbon porous body PC4 that was not heat-treated in the presence of coconut shell activated carbon. It was larger than the nitrogen adsorption amount A3 of the carbon porous body contained in PC5 and adsorbent AM6.

(Measurement of pentane detachment rate)
The pentane desorption rate was measured for the carbon porous bodies (activated carbon) used for the carbon porous bodies PC1 to PC5 and the adsorbent AM6.
Specifically, first, 3 g of each carbon porous body was weighed and filled in a glass column. Each column was then attached to a gas adsorber. The mass of the carbon porous body at this time was defined as the carbon porous body amount A.

  Subsequently, pentane was bubbled with nitrogen gas at a temperature of 25 ± 1 ° C. to generate a mixed gas of nitrogen gas and pentane gas, and this mixed gas was circulated through each column to adsorb pentane to the carbon porous body. During this adsorption treatment, the temperature of the mixed gas was 25 ° C., and pentane was contained at a saturated concentration in this mixed gas.

  Next, each column was removed from the gas adsorber after a certain period of time, the column mass was measured, and then each column was reattached to the gas adsorber. Then, when the column mass at a certain point in time is the same as the column mass obtained by the immediately preceding measurement, it is judged that the saturated adsorption state has been reached, and the mass of the carbon porous body is calculated from the column mass at this point. Thus, the mass after adsorption was set to B.

Next, nitrogen gas at a temperature of 25 ° C. was passed through each column to desorb pentane from the carbon porous body.
Next, the column mass was measured when the flow rate of nitrogen gas reached 150 times the volume of the carbon porous material, and the mass of the carbon porous material was calculated from this column mass. Thus, mass C after desorption when the bed volume was 150 was obtained.
Next, the column mass when the flow rate of nitrogen gas reached 300 times the volume of the carbon porous body was measured, and the mass of the carbon porous body was calculated from the column mass. Thus, mass D after desorption when the bed volume was 300 was obtained.

  Here, the value obtained by subtracting the carbon porous material amount A from the post-adsorption mass B was defined as the adsorption amount per column (BA). Further, the value obtained by dividing the adsorption amount per column by the mass of the carbon porous body was defined as the pentane adsorption amount (g / g) per unit mass of each carbon porous body.

  Further, the value obtained by subtracting the post-desorption mass C from the post-adsorption mass B was defined as the desorption amount per column when the bed volume was 150 (BC). Next, the value obtained by dividing the desorption amount per column (BC) by the adsorption amount per column (BA) is the pentane desorption rate when the bed volume is 150 [(BC) / (B− A) × 100] (%).

  Similarly, the value obtained by subtracting the post-desorption mass D when the bed volume is 300 from the post-adsorption mass B was defined as the desorption amount per column (BD). Next, the value obtained by dividing the desorption amount per column (BD) by the adsorption amount per column (BA) is the pentane desorption rate when the bed volume is 300 [(BD) / (B− A) × 100] (%).

In each of Experimental Examples 7 to 10, the pentane adsorption amount per unit mass of the carbon porous body is the pentane adsorption amount per unit mass of the carbon porous body obtained by the above measurement. The weighted average was calculated according to the mass ratio of the carbon porous body.
The pentane desorption rate when the bed volume according to Experimental Examples 7 to 10 was 150 and the pentane desorption rate when the bed volume was 300 were also calculated by weighted averaging in the same manner as the pentane adsorption amount.
The results are shown in Table 2.

  In Table 2 above, among the columns below the heading “Canister”, the column labeled “front chamber” indicates the type of adsorbent contained in the front chamber and the amount of each adsorbent in the total amount of adsorbent. The ratio is described. The column labeled “rear chamber” describes the type of adsorbent contained in the rear chamber and the ratio of each adsorbent to the total amount of adsorbent.

  In Table 2, the column labeled “pentane adsorption amount (g / g)” describes the pentane adsorption amount per unit mass of the carbon porous body obtained by the pentane desorption test. Yes.

  Further, in Table 2 above, among the columns below the heading “Pentane Desorption Rate (%)”, the column labeled “150 BV” shows the bed obtained by the above pentane desorption test. The pentane desorption rate when the volume is 150 is shown. In the column labeled “300 BV”, the pentane desorption rate when the bed volume is 300 obtained by the above pentane desorption test is described.

FIG. 6 is a graph showing an example of the relationship between the nitrogen adsorption amount A3 and the pentane desorption rate when the nitrogen relative pressure P / P ₀ is 0.99 in the nitrogen adsorption isotherm measured at a temperature of 77K. FIG. 6 is created using the data obtained in Experimental Examples 1 to 10. In the graph shown in FIG. 6, the horizontal axis represents the nitrogen adsorption amount A3 of the carbon porous bodies PC1 to PC5, the carbon porous bodies used for the adsorbent AM6, and the entire carbon porous bodies included in the canisters C7 to C10. The vertical axis represents the pentane detachment rate when the bed volume of the carbon porous bodies PC1 to PC5 and the carbon porous bodies used in the adsorbent AM6 and the entire carbon porous bodies included in the canisters C7 to C10 is 150.

As shown in FIG. 6, a canister using a carbon porous body having a large nitrogen adsorption amount A3 as the adsorbing material when the nitrogen relative pressure P / P ₀ is 0.99 tends to have a high pentane desorption rate.

  DESCRIPTION OF SYMBOLS 10 ... Canister, 11 ... Container, 12 ... Porous board, 13 ... Adsorbent, 13a ... First adsorbent, 13b ... Second adsorbent, 14 ... Adsorbent layer, IP1 ... Air supply port, IP2 ... Air supply port , OP ... exhaust port, PP ... partition plate.

Claims (2)

A container and a carbon porous body accommodated in the container;
The carbon porous body is a canister having a nitrogen adsorption isotherm of 1500 cm ³ (STP) / g or more when the nitrogen relative pressure P / P ₀ is 0.99 on the nitrogen adsorption isotherm measured at a temperature of 77K. The alkaline earth metal salt of benzenedicarboxylic acid is heated at a temperature in the range of 550 ° C. to 700 ° C. in an inert atmosphere in the presence of a trapping material that adsorbs hydrocarbon gas, and carbon and alkaline earth metal Forming a complex with carbonate;
Cleaning the composite with a cleaning solution capable of dissolving the carbonate, and removing the carbonate from the composite to obtain a carbon porous body.