JP2007281427A - Method for manufacturing activated carbon for electric double layer capacitor or coal as its raw material, and installation for manufacturing activated carbon for electric double layer capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing activated carbon for an electric double layer capacitor whose pore distribution is desirable or coal as its raw material, and also to provide an installation for manufacturing activated carbon for electric double layer capacitor. <P>SOLUTION: The installation 1 for manufacturing activated carbon for electric double layer capacitor or coal as its raw material comprises: an apparatus 10 for producing super-elevated temperature superheated steam by heating steam to the temperature of 900°C or more; and an activation furnace 20 in which activation of carbonaceous material is carried out by using the super-elevated temperature superheated steam obtained in the apparatus 10 for producing super-elevated temperature superheated steam. The apparatus 10 for producing super-elevated temperature superheated steam has: a heat accumulator in which steam passages consisting of a plurality of cell pores are formed; and a heat supply means for supplying heat to the heat accumulator. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing activated carbon for electric double layer capacitors or a raw coal thereof, and an apparatus for producing activated carbon for electric double layer capacitors.

In the activated carbon for electric double layer capacitors, the specific surface area, the optimum range of pore distribution, and the like are determined according to the target capacitor characteristics and the type of electrolyte used.
For example, in Patent Document 1 (Japanese Patent Laid-Open No. 63-187614), the specific surface area is 1800 to 3500 m ² / g, and the volume ratio of pores having a pore diameter of 20 mm or more to the total pore volume is 20 to 40%. It is disclosed that a highly reliable electric double layer capacitor excellent in initial capacitance, internal resistance and low temperature characteristics can be obtained by using a polarizable electrode made of this activated carbon. .
Patent Document 2 (Japanese Patent Laid-Open No. 2000-247621) discloses an activated carbon composed of glassy carbon having an average particle diameter of 1 to 30 μm and a specific surface area of 1000 m ² / g or more as an activated carbon suitable for an organic capacitor. Has been.

In Patent Document 3 (Japanese Patent Laid-Open No. 2001-89119), the specific surface area is 1000 to 2500 m ² / g, and the pore volume within the pore diameter range of 20 to 200 mm is 20 to 70% of the total pore volume (Examples). An activated carbon having a calculated value of 0.25 to 0.82 cm ³ / g) is disclosed. By using a polarizable electrode made of this activated carbon, an electric double layer capacitor having a high capacitance density per volume and a low internal resistance can be obtained. It is described that it is obtained.
In Patent Document 4 (Japanese Patent Laid-Open No. 2002-33249), the specific surface area is 2000 to 2500 m ² / g, the average pore diameter is 19.5 to 22 mm, and the pore volume is 50 to 300 mm. 0.15 cm ³ / g of activated carbon is disclosed, by using the polarizable electrode composed of activated carbon, and when charging and discharging are repeated under a large current, when a constant voltage is applied for a long time continuously, the output It is disclosed that an electric double layer capacitor with a small density reduction can be obtained.
In Patent Document 5 (International Publication No. WO 2004/019356 pamphlet), as the activated carbon suitable for an electric double layer capacitor using an ionic liquid as an electrolyte, the peak of the pore radius distribution of micropores determined by the MP method is 4 to 4. An 8 kg activated carbon is disclosed.

As disclosed in each of the above patent documents, the specific range of activated carbon used for the polarizable electrode and the optimum range of pore distribution are determined according to the characteristics of the desired capacitor and the type of the electrolyte solution. When designing capacitors that emphasize output characteristics such as cycle charge / discharge characteristics and large current charge / discharge characteristics in low temperature environments, the average pore diameter is large, and not only micropores but also pore volumes of 20 mm or more in diameter It is known that a large proportion of is preferable.
In order to obtain such activated carbon, it is necessary to increase the degree of activation, but if the degree of activation is increased to a certain extent, the specific surface area and total pore volume are reduced from saturation to decrease as the pore diameter increases. The yield of activated carbon is significantly reduced.

As specific methods for increasing the degree of activation, three methods are conceivable: (1) increasing the amount of activator, (2) increasing the processing temperature, and (3) increasing the processing time.
First, regarding (1), if chemical activation is used, the addition amount of an activator such as potassium hydroxide, sodium hydroxide, or zinc chloride is increased. If gas activation is used, the gas composition ratio of water vapor, carbon dioxide, etc. is increased. However, an increase in the amount of activator added causes an increase in raw material costs, activated carbon neutralization and cleaning costs, and exhaust gas wastewater treatment costs. In particular, in steam activation, if the amount of steam, which is an activation gas, is increased, the furnace temperature tends to fluctuate, which makes it difficult to stabilize the processing temperature.

Regarding (2), considering the safety related to the activator used and the consumption of furnace materials, there is a limit on the maximum temperature for each activation method, and it is difficult to process at high temperatures far from the range of the prior art. It is.
With regard to (3), when the degree of activation is increased by extending the treatment time, the yield of activated carbon decreases, and the desired fineness is also greatly affected by the properties and particle size of the carbon material that is the precursor of activated carbon. It becomes difficult to stably produce activated carbon having a pore distribution.
Although each of the above-mentioned patent documents discloses a suitable pore distribution of activated carbon, the production method only discloses a general activation method, and activated carbon having a desired pore distribution. However, an efficient production method capable of stably obtaining a large amount is not disclosed in these documents, and no such production method has been established so far.

JP-A 63-187614 JP 2000-247621 A JP 2001-89119 A JP 2002-33249 A International Publication No. 2004/019356 Pamphlet

  The present invention has been made in view of such circumstances, and provides a method for producing activated carbon for an electric double layer capacitor or a raw coal thereof having a desired pore distribution, and an apparatus for producing activated carbon for an electric double layer capacitor. The purpose is to do.

  As a result of intensive studies to achieve the above object, the present inventor has used pore carbon suitable for an electric double layer capacitor by using raw coal activated with superheated superheated steam heated to 900 ° C. or higher. The inventors have found that activated carbon having a distribution can be produced in a large amount and stably in a high yield, and the present invention has been completed.

That is, the present invention
1. An ultra-high temperature superheated steam production apparatus that heats water vapor to 900 ° C. or higher to form super-high temperature superheated steam, an activation furnace that activates a carbonaceous material with the ultra-high temperature superheated steam obtained by the ultra-high temperature superheated steam production apparatus, An apparatus for producing an activated carbon for an electric double layer capacitor or a raw coal for the same, wherein the super-high temperature superheated steam production apparatus includes a heat storage body in which a steam flow path including a plurality of cell holes is formed, and the heat storage body. An apparatus for producing activated carbon for an electric double layer capacitor or a raw coal thereof, comprising: a heat supply means for supplying heat;
2. A method for producing an activated carbon for an electric double layer capacitor, wherein the carbon material is activated with ultra-high temperature superheated steam heated to 900 ° C. or more to obtain a raw material coal, and then the raw material coal is further activated,
3. 2. The method for producing activated carbon for electric double layer capacitors, wherein the raw coal is activated with superheated steam of less than 900 ° C.,
4). Obtained by an ultra-high temperature superheated steam production apparatus having a heat storage body in which a water vapor flow path composed of a plurality of cell holes is formed and a heat supply means for supplying heat to the heat storage body and capable of heating water vapor to 900 ° C. or higher. The obtained super-high temperature superheated steam at 900 ° C. or higher is introduced into an activation furnace, and in this furnace, the carbonaceous material is activated with the ultra-high temperature superheated steam to form raw coal, and then, in the same activation furnace, 500 A method for producing activated carbon for an electric double layer capacitor is further provided, wherein the raw coal is further activated with superheated steam at a temperature of from 0C to 900C.

The raw carbon of the activated carbon for the electric double layer capacitor of the present invention is obtained by activating a carbonaceous material with ultra-high temperature superheated steam at 900 ° C. or higher, or having a predetermined BET specific surface area and average pore diameter, BJH method Since the pore volume between 2.0 and 20.0 nm required in the above range is within a predetermined range, the pore diameter during activation is directional, and the pores are easy to control. In addition, the activated carbon can be led to activated carbon for electric double layer capacitors having a desired pore distribution in a high activation yield and in a short time.
The activated carbon for electric double layer capacitors obtained from this raw coal has a suitable pore distribution, is easy to diffuse ions, and has a large capacitance density per volume. In addition, this electric double layer capacitor using activated carbon has low internal resistance, especially direct current internal resistance, high output density per volume, and excellent charge / discharge characteristics in a low temperature environment. It has various advantages such as excellent cycle charge / discharge durability and continuous charge durability at high voltage.
In addition, the activated carbon for electric double layer capacitor of the present invention or the apparatus for producing the raw coal provided with the super high temperature superheated steam generator has high thermal efficiency and has a small amount of scale generated in the steam generating section. Further, there is an advantage that the consumption of the furnace material is small and the amount of the furnace material mixed into the product is small. In the method for producing activated carbon using this apparatus, the production of raw coal using activation with superheated superheated steam and the production of activated carbon using activation with normal superheated steam can be performed continuously. Moreover, the heat processing for surface functional group control of the obtained activated carbon can also be performed simultaneously.

Hereinafter, the present invention will be described in more detail.
[Coking coal for activated carbon for electric double layer capacitors]
The raw carbon of the activated carbon for the electric double layer capacitor according to the present invention is activated carbon that is an intermediate raw material of activated carbon having a pore structure suitable as an electrode material of the electric double layer capacitor, and is obtained by (1) nitrogen adsorption method. The BET specific surface area is 1500 to 2000 m ² / g, the average pore diameter is 1.6 nm or more and less than 1.95 nm, and the pore volume between 2.0 and 20.0 nm as determined by the BJH method (hereinafter, (Mesopore volume) is 0.08 cm ³ / g or more and less than 0.30 cm ³ / g, or (2) a carbonaceous material is activated with superheated steam at 900 ° C. or higher.

In the raw coal of (1), when the BET specific surface area, the average pore diameter, and the mesopore volume are too small or too large beyond the above ranges, this is further activated to obtain activated carbon for an electric double layer capacitor. The activation yield is likely to decrease. In order to further increase the activation yield, the BET specific surface area is 1600 to 1900 m ² / g, the average pore diameter is 1.7 to 1.9 nm, and the mesopore volume is 0.10 to 0.30 cm ³ / g. In particular, the mesopore volume is more preferably 0.15 to 0.30 cm ³ / g.

(2) The raw material coal obtained by activating a carbonaceous material with superheated steam at 900 ° C. or higher is not particularly limited as long as it is obtained under these conditions.
The temperature of water vapor used for activation is 900 ° C. or higher, preferably 1000 ° C. or higher, more preferably 1200 ° C. or higher.
Here, the steam heated to 900 ° C. or higher, called super-high temperature superheated steam, is different from superheated steam near 500 ° C. used for general steam activation, in addition to water molecules in a gaseous state, Since the presence frequency of hydrogen, oxygen, hydroxide ions and radicals increases, the activation gas has a high activity.
In the activation with superheated superheated steam at 900 ° C. or higher, it is considered that a reaction that complements the deficient part (pore part) of activated carbon occurs along with the activation (oxidation reaction), and actually activated using superheated superheated steam. When the time is extended, the total pore volume and specific surface area increase, but the peak pore diameter of the pore size distribution does not shift, and the peak pore diameter in the MP method is maintained at 0.5 to 0.7 nm. The
In this way, when the raw material coal having a large specific surface area without increasing the peak pore diameter is used as an intermediate raw material and further subjected to normal activation treatment, a pore structure suitable as an electrode material for an electric double layer capacitor is obtained. You can get activated charcoal.

The environment in which the superheated superheated steam and the carbon material are brought into contact with each other may be steam only, or in the presence of an inert gas such as nitrogen or argon, but in order to perform stable activation, heated nitrogen or argon is used. It is preferable to use it as a flow gas. At this time, the concentration of the superheated superheated steam to be contacted is not particularly limited, but is preferably 30 to 100% by volume, particularly 50 to 100% by volume for efficient activation.
Note that the super-high-temperature superheated steam can be obtained by a high-temperature superheated steam production apparatus described in detail later.

The coking coal in this case also has a BET specific surface area of 1500 to 2000 m ² / g determined by a BET method using a nitrogen adsorption method, and an average pore diameter of 1.6 nm or more and less than 1.95 nm, considering the activation yield in the subsequent step. And the pore volume calculated | required by BJH method is 0.08 cm < ³ > / g or more and less than 0.30 cm < ³ > / g, BET specific surface area is 1600-1900 m < ² > / g, and average pore diameter is 1.7-1. .9Nm, preferably mesopore volume is 0.10~0.30cm ³ / g, in particular, it is more preferred mesopore volume is 0.15~0.30cm ³ / g.

  The carbon material used as a precursor for each of the raw coals is not particularly limited as long as it is used as a raw carbon material for ordinary activated carbon for electric double layer capacitors. For example, coconut shells, coffee beans, wood chips, petroleum-based materials Pitch, petroleum coke, mesophase carbon, tar pitch fiber, phenol resin, furan resin, polyvinyl chloride resin, polyvinylidene chloride resin, polyimide resin, polyamide resin, liquid crystal polymer, plastic waste, waste tire, etc. be able to. Moreover, although there exist various shapes, such as a crushed shape, a granule, a granule, a fiber, a felt, a textile fabric, and a sheet form, all can be used by this invention.

[Activated carbon for electric double layer capacitors]
The activated carbon for an electric double layer capacitor according to the present invention is obtained by activating the above-mentioned raw coal, has a BET specific surface area of 1700 to 2500 m ² / g determined by a nitrogen adsorption method, and a mesopore volume determined by a BJH method. 0.30 to 0.70 cm ³ / g.
As an activation method, any of a gas activation method using steam activation, an alkali activation method using KOH, or a combination of these methods can be used, but the pores are expanded from the raw coal to increase the mesopore volume. Therefore, steam activation using normal superheated steam is particularly preferable.

In the activated carbon for an electric double layer capacitor of the present invention, there is a high possibility that the capacitance density per unit weight is lowered if the BET specific surface area is too small or too large beyond the above range. Considering that enhance the capacitance density, BET specific surface area is preferably ^{1800~2400m 2 / g, 2000~2300m 2 /} g is more preferable.
On the other hand, if the mesopore volume is smaller than 0.30 cm ³ / g, diffusion of ions in the pores is inhibited during charge / discharge of a large current, and the internal resistance is likely to increase. And 0.70cm larger ³ / g, the bulk density of the activated carbon is decreased, the output per unit volume is likely to decrease. Reduced more the internal resistance, in order to increase the output, mesopore volume preferably ^{0.35~0.65cm 3 / g, 0.40~0.60cm 3 /} g is more preferable.
The particle size of the activated carbon is preferably 1 to 20 μm, more preferably 3 to 15 μm in terms of average particle size from the viewpoint of internal resistance.

By using the activated carbon obtained by activating the specific raw material coal of the present invention as described above as an electrode material of an electric double layer capacitor, a capacitor excellent in capacitance and electrode density can be obtained.
When an electric double layer capacitor electrode material is used, an electrode composition comprising the activated carbon for an electric double layer capacitor of the present invention as a main component, and further containing a binder polymer and, if necessary, a conductive material in the activated carbon is provided on the current collector. What was apply | coated to can be used.
In this case, the binder polymer, the conductive material, and the current collector are not particularly limited, and may be appropriately selected from known ones.

Examples of the binder polymer include fluorine resins such as polytetrafluoroethylene, polyvinylidene fluoride, and fluoroolefin copolymer cross-linked polymers, polysaccharides such as carboxymethyl cellulose, latex such as styrene butadiene copolymer, polyimide, polyamideimide, and phenol. A thermosetting resin such as a resin can be used.
The addition amount of a binder polymer can be 0.5-20 mass parts with respect to 100 mass parts of activated carbon, for example, Preferably it is 1-10 mass parts.

Examples of the conductive material added as necessary include carbon black, ketjen black, acetylene black, carbon whisker, carbon fiber, natural graphite, artificial graphite, (oxide) titanium, ruthenium oxide, aluminum, nickel, and other metals. A fiber etc. are mentioned, These 1 type can be used individually or in combination of 2 or more types.
The amount of the conductive material added can be, for example, 0.1 to 20 parts by mass, preferably 0.5 to 10 parts by mass with respect to 100 parts by mass of the activated carbon.

In addition, there is no limitation in particular in the preparation method of an electrode composition, For example, activated carbon, a binder polymer, and the electrically conductive material added as needed can also be prepared in a solution form, Moreover, as needed to this solution It can also be prepared by adding a solvent.
An electrode can be obtained by applying the electrode composition thus obtained onto a current collector. The application method is not particularly limited, and a known application method such as a doctor blade or an air knife may be appropriately employed.
As the positive electrode current collector, aluminum or aluminum oxide is preferably used. On the other hand, as the negative electrode current collector, aluminum, aluminum oxide, copper, nickel, or a metal whose surface is formed of a copper plating film or a nickel plating film is used. Etc. are preferably used.

As a shape of the metal or the like constituting each of the current collectors, a thin foil shape, a sheet shape spread on a plane, a stampable sheet shape with holes formed, or the like can be adopted. Moreover, as the thickness, it is about 1-200 micrometers normally.
The electrode can also be formed by melt-kneading the electrode composition or kneading in the presence of a solvent, followed by extrusion and film forming.

[Electric double layer capacitor]
The electric double layer capacitor according to the present invention comprises a pair of polarizable electrodes, a separator interposed between the electrodes, and an electrolyte, and at least one of the pair of polarizable electrodes is configured as described above. The obtained electrode is used. In this case, other capacitor components other than the electrodes may be appropriately selected from known members.
As an example of the manufacturing method, an electric double layer capacitor structure having a separator interposed between the pair of electrodes obtained as described above is laminated, folded, or wound as necessary. After being housed in a battery container such as a battery can or a laminate pack, there is a method of assembling by filling the electrolyte, sealing the battery can, and heat sealing the laminate pack. However, the present invention is not limited to this, and an appropriate method may be used depending on the type of capacitor constituent member.

  The electric double layer capacitor of the present invention is a memory backup power source for mobile phones, notebook computers and portable terminals, power sources for mobile phones and portable audio equipment, power supplies for instantaneous power failures such as personal computers, solar power generation, It can be suitably used for various low current power storage devices such as a load leveling power source by combining with wind power generation. An electric double layer capacitor that can be charged and discharged with a large current can be suitably used as a large current storage device that requires a large current, such as an electric vehicle or a power tool.

[Method for producing activated carbon for electric double layer capacitor]
The method for producing an activated carbon for an electric double layer capacitor according to the present invention is to further activate the raw coal after activating the carbon material with ultra-high temperature superheated steam heated to 900 ° C. or higher to obtain the raw coal. .
The temperature of the superheated superheated steam may be 900 ° C or higher, but is preferably 1000 ° C or higher, more preferably 1200 ° C or higher.
As already described, there is no particular limitation on the method for activating the raw coal, but it is preferable to use a general steam activation method that is activated with superheated steam of less than 900 ° C.
Even if the process of further activating the raw material coal is separate from the step of activating the carbon material with ultra-high temperature superheated steam to produce the raw material coal, the carbon material is first brought into contact with the ultrahigh temperature superheated steam in the same furnace, In this case, it may be a continuous process in which the furnace temperature is lowered and the normal superheated steam is brought into contact with the raw coal, but the latter is preferred from the viewpoint of production efficiency. The normal superheated steam may be separately introduced into the furnace, or the super high temperature superheated steam may be cooled to less than 900 ° C. and used.

The temperature in the furnace is preferably variable in the range of 500 to 1300 ° C., and the temperature of the steam is adjusted from 900 ° C. or higher at the time of supply to a desired temperature by controlling the furnace temperature. What is necessary is just to adjust a hole structure.
The environment in the furnace during coking coal production or further activation of the coking coal may be steam only, but it is preferable to flow in an inert gas such as nitrogen, argon, helium, xenon as described above. As described above, the amount of water vapor at that time is preferably 30 to 100% by volume for efficient activation.
The form of the furnace may be a batch furnace or a continuous furnace such as a rotary kiln or roller hearth kiln.

[Electric double layer capacitor activated carbon or its raw coal production equipment]
The production apparatus for activated carbon for electric double layer capacitors and the like according to the present invention was obtained with an ultra-high temperature superheated steam production apparatus that heats steam to 900 ° C. or higher to produce super-high temperature superheated steam, and this ultra-high temperature superheated steam production apparatus. And an activation furnace that activates the carbonaceous material with the super-high-temperature superheated steam, and the super-high-temperature superheated steam production device supplies heat to the heat storage body in which a steam flow path composed of a plurality of cell holes is formed, and the heat storage body Heat supply means.
Here, as the ultra-high temperature superheated steam production apparatus, an apparatus disclosed in Japanese Patent Application Laid-Open No. 2005-325021 that has a heat storage body having a honeycomb-like structure with extremely excellent thermal efficiency can be used.
As the activation furnace, it can be appropriately selected from known activation furnaces used for activated carbon activation such as the batch furnace, rotary kiln, and roller hearth kiln described above, but only in the amount of heat of superheated superheated steam. It is preferable to provide an external heating type heating means so that not only the temperature can be raised but also the temperature can be adjusted by a furnace alone.
It is preferable to supply the superheated superheated steam into the activation furnace from the vicinity of the raw material charging port so that the temperature of the steam supplied from the raw material charging side to the activated carbon extraction side decreases.

The ultra-high temperature superheated steam production apparatus can also be used as a heat source for carbonization treatment, so that it is possible to produce carbonaceous materials using coconut shells, thermosetting resin, infusible pitch, etc. before carbonization as raw materials. The coking coal can be produced at the same time.
In addition, in the ultra high temperature superheated steam obtained by the above ultra high temperature superheated steam production apparatus, hydrogen, oxygen, hydroxide ions and radicals are present in addition to gaseous water molecules. It is also possible to control the oxygen content. For this reason, after the normal activation, the heat treatment step performed for the purpose of controlling the surface functional group amount can be performed simultaneously with the production of the raw coal.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 shows a production apparatus 1 (hereinafter referred to as activated carbon production apparatus 1) for activated carbon for electric double layer capacitors according to the present invention.
The activated carbon production apparatus 1 includes an ultra-high temperature superheated steam production apparatus 10 (hereinafter referred to as the steam production apparatus 10) and a rotary kiln type activation furnace 20.

As shown in FIG. 2, the steam production apparatus 10 includes a pair of heat storage heat exchange systems 2 </ b> A and 2 </ b> B configured in parallel.
The heat storage type heat exchange system 2A includes a combustion chamber 12A formed by dividing the inside of a cylindrical main body 11 having a substantially frustoconical water vapor discharge port 17 formed at one end by a partition wall 11A, and a honeycomb adjacent to the combustion chamber 12A. 14A having a gas flow path 141A and a supply / exhaust switching valve 142A for sucking steam into the heat storage body 13A or exhausting high temperature gas from the heat storage body 13A. Are arranged in series in this order.
Similarly, in the heat storage type heat exchange system 2B, the combustion chamber 12B, the honeycomb-shaped heat storage bodies 13B and 15B, and the supply / exhaust switching device 14B having the gas flow path 141B and the supply / exhaust switching valve 142B are arranged in this order in series. Has been configured.

The honeycomb-shaped heat accumulators 13A, B and 15A, B are the same as the heat accumulators described in Japanese Patent Application Laid-Open No. 2005-325021, and the water vapor or high temperature gas flow channel 131 composed of a plurality of cell holes is formed. It has a honeycomb structure. In this case, the cross-sectional shape of the channel 131 is arbitrary, and various shapes such as a rectangle, a square, a triangle, and a circle can be adopted.
Burners 16A and B, which are heat supply means, are provided on the peripheral walls (main body 11) of the combustion chambers 12A and B, respectively, so that the honeycomb-shaped heat accumulators 13A and B and 15A and B are burned by burning the fuel gas. Is supplied with heat.

On the other hand, as shown in FIG. 1, the rotary kiln type activation furnace 20 includes a rotary cylindrical furnace 21 and a heating furnace 22 as a heating means provided so as to cover the periphery of the rotary cylindrical furnace 21. Here, one end of the rotary cylindrical furnace 21 is connected to the water vapor outlet 17 of the water vapor production apparatus 10 via the joint 30. Thus, by connecting the steam production apparatus 10 and the rotary kiln type activation furnace 20 directly via the joint 30, higher temperature steam can be introduced into the activation furnace 20.
The joint 30 is provided with a cylindrical carbon material inlet 23 from which the carbon material is supplied into the rotary cylindrical furnace 21. Furthermore, a cylindrical activated carbon outlet 24 is provided at the end of the rotary cylindrical furnace 21 opposite to the joint 30, and activated carbon (coking coal) activated by ultra-high temperature superheated steam or the like is taken out from here. It is.
The heating furnace 22 includes a heater (not shown) that can heat the rotary cylindrical furnace 21 and the temperature of the superheated superheated steam supplied to the inside of the rotary cylindrical furnace 21 increases toward the activated carbon outlet 24 side. Control to decrease.
A driving force of a motor 25 that is a driving source is transmitted to the rotating cylindrical furnace 21 via a belt 26 that is a driving force transmitting means, whereby the rotating cylindrical furnace 21 freely rotates.

The raw material carbon of activated carbon and the manufacturing method of activated carbon using the activated carbon manufacturing apparatus 1 comprised as mentioned above are demonstrated.
[1] Production of super-high-temperature superheated steam First, in the steam production apparatus 10, the supply / exhaust switching valve 142B of the heat storage type heat exchange system 2B is switched to the high-temperature gas exhaust side, and combustion of fuel gas is performed in the combustion chamber 12B using the burner 16B. The honeycomb-shaped heat accumulator 13B is heated by the sensible heat of the combustion exhaust gas to become a high temperature state, and the combustion exhaust gas becomes a low temperature of 150 ° C. to 200 ° C. and is discharged through the gas flow path 141B. Further, since the honeycomb-shaped heat storage body 15B faces the combustion chamber, the honeycomb-shaped heat storage body 15B receives the radiant heat from the flame, and the exhaust gas also flows in slightly, so that it is heated simultaneously with the honeycomb-shaped heat storage body 13B. Next, similarly in the heat storage type heat exchange system 2A, the supply / exhaust switching valve 142A is switched to the exhaust side of the high temperature gas A, the fuel gas is combusted in the combustion chamber 12A using the burner 16A, and the honeycomb heat storage bodies 13A, 15A. Is heated to a high temperature state.

  While heat is stored in the honeycomb-shaped heat storage body 13A, the supply / exhaust switching valve 142B of the heat storage type heat exchange system 2B is switched to the steam introduction side, and saturated steam B of about 120 ° C. to 140 ° C. is supplied to the honeycomb through the gas flow path 141B. It introduce | transduces into the flow path 131 of the state heat storage body 13B. As a result, the water vapor A in contact with the honeycomb-shaped heat storage body 13B is heated to 900 ° C. or more to become super-high-temperature superheated water vapor C, passes through the honeycomb-shaped heat storage body 15B, and is discharged from the water vapor discharge port 17. In this case, the honeycomb-shaped heat accumulator 15B is constantly exposed to a high temperature due to the radiant heat from the combustion flame that occurs in the adjacent combustion chamber and the passage of the super-high-temperature superheated steam, so that the temperature does not decrease and is almost constant. Therefore, the temperature of the superheated superheated steam passing therethrough is suppressed.

When the honeycomb-shaped heat accumulator 13B is brought into contact with water vapor to generate super-high-temperature superheated water vapor, the temperature on the low temperature side is close to the introduction water vapor temperature in about 15 to 30 seconds, depending on the amount and temperature of the water vapor introduced. In addition, the temperature on the high temperature side decreases to about 900 ° C. In response to the temperature drop of the heat storage body 13B, the supply / exhaust switching valve 142B is switched to the high temperature gas exhaust side again, combustion is started in the combustion chamber 12B, and the heat storage body 13B is reheated. Similarly, steam is supplied to the 2A side to generate high-temperature superheated steam.
In this way, the heating by the combustion gas and the introduction of the steam are alternately performed in a cycle of about 15 to 30 seconds between the heat storage bodies 13A and 13B, so that the super high temperature is discharged from the steam outlet 17 of the super high temperature superheated steam production apparatus 10. The superheated steam C can be continuously supplied to the rotary kiln type activation furnace 20.

[2] Production of raw coal and activated carbon Subsequently, a carbon material is charged into the rotary cylindrical furnace 21 of the rotary kiln type activation furnace 20 through the carbon material charging port 23. The charged carbon material is activated in contact with ultra-high temperature superheated steam at 900 ° C. or higher supplied from the steam production apparatus 10 in the rotary cylindrical furnace 21 to become raw coal.
This coking coal is further activated with water vapor of less than 900 ° C. by moving in the rotary cylindrical furnace 21 to the downstream side and moving in an atmosphere in which the furnace temperature in the vicinity of the activated carbon outlet 24 is lowered. The activated carbon for an electric double layer capacitor has a specific surface area, a pore diameter, and a pore volume.

In addition, in the said embodiment, although the rotary kiln type | mold activation furnace 20 was used as an activation furnace, it is not limited to this, Various well-known activation furnaces as mentioned above can be used.
Also, the steam production apparatus has a heat storage body in which a steam flow path composed of a plurality of cell holes is formed and a heat supply means, and may be anything that can superheat steam to 900 ° C. or more, and other specific examples. The structure, shape, and the like can be changed as appropriate.

  EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated more concretely, this invention is not limited to the following Example.

[Examples 1 to 3 and Comparative Examples 1 and 2]
[1] Charcoal for activated carbon for electric double layer capacitor and activated carbon for electric double layer capacitor Palm pattern activated carbon for adsorbent (Y-10S, Ajinomoto Fine Techno Co., Ltd., 4-8 mesh) is shown in FIG. Using the activated carbon production apparatus 1 shown, steam activation was performed under the conditions shown in Table 1 to obtain raw coal.
Next, the obtained raw coal was steam activated under the conditions shown in Table 1 using the same apparatus to obtain activated carbon for capacitors. In addition, only the water vapor | steam was supplied except having made nitrogen gas flow when the rotary kiln type | mold activation furnace 20 temperature rising and temperature falling.
The obtained activated carbon was washed in hydrochloric acid, and then repeatedly washed with demineralized water until the pH of the washing became 7.0 or higher. After washing, the activated carbon was dried and pulverized using a ball mill until the average particle size became 8 to 12 μm.

For each of the raw coal obtained in each of the above Examples and Comparative Examples and the activated carbon for capacitors, the BET specific surface area, the average pore diameter, the mesopore volume in the BJH method (the pore diameter between 2.0 and 20.0 nm). Table 2 shows the activation yield from the carbon material. In addition, the above physical-property value was measured using the Tristar 3000 type (made by Shimadzu Corporation).
As shown in Table 2, in Examples 1 to 3 using raw coal activated by super high temperature superheated steam at 900 ° C. or higher, activated carbon having high specific surface area and mesopore volume suitable for activated carbon for capacitors has a high activation yield. It can be seen that the rate is obtained.

[Examples 4 to 6 and Comparative Examples 3 and 4]
[2] Electric Double Layer Capacitor Each activated carbon obtained in Examples 1 to 3 and Comparative Examples 1 and 2, a conductive agent (HS-100, manufactured by Denki Kagaku Kogyo Co., Ltd.), and PVDF (Aldrich) as a binder Manufactured in a coating solvent N-methylpyrrolidone (hereinafter referred to as NMP) so as to have a mass composition of 80:10:10. Prepared.
The mass of the activated carbon contained in the polarizable electrode per unit area is the same for each sample on both sides of the etched aluminum foil (30CB, manufactured by Nihon Densetsu Kogyo Co., Ltd.) as the current collector. After coating and forming as described above, rolling was performed with a roll press, and NMP was further removed by drying to obtain a polarizable electrode.
The obtained polarizable electrodes were used as nine positive electrodes and ten negative electrodes, and these were alternately stacked via separators (TF40-35, manufactured by Nippon Kogyo Paper Industries Co., Ltd.) and collected together for each positive and negative. An electrode group was obtained by welding with an aluminum current extraction terminal. Next, the electrode group was provided with a valve made of aluminum laminate (Dai Nippon Printing Co., Ltd., outer layer: 6-nylon / thickness 25 μm, gas barrier layer: soft aluminum / thickness 40 μm, inner layer: polypropylene + modified polypropylene / 30 + 15 μm). After inserting into the outer package and injecting and impregnating the organic electrolyte, the outer package was heat-sealed to obtain an electric double layer capacitor. The organic electrolyte is 1.5 mol / L in diethyl (2-methoxyethyl) methylammonium tetrafluoroborate (DEME-BF ₄ ) as the electrolyte and propylene carbonate (PC) as the electrolyte solvent. The dissolved solution was used.

The following tests were conducted on the capacitors obtained in Examples 4 to 6 and Comparative Examples 3 and 4. The results are shown in Table 3.
[Capacitance measurement]
Charge at constant current up to 3.0V at an hourly current value, perform constant voltage charge for 30 minutes, and then discharge at constant current from 3.0V to 0V at an hourly current value. The capacitance was calculated from the amount of energy.
[Measure internal resistance and calculate power density per volume]
The internal resistance is a constant current charge up to 3.0V at a current value of 1 hour rate, and after performing a constant voltage charge for 30 minutes as it is, a constant current discharge is performed at a current value of 1/30 hour rate from 3.0V. The DC resistance obtained from the intersection of the approximate straight line between 5 to 10 seconds after discharge and the 0 second Y-axis of the discharge curve.
In addition, when measuring the internal resistance at the time of low temperature, the capacitor was allowed to stand for 6 hours in a thermostatic bath at −30 ° C. and then measured in the same manner. The output density per volume was determined in accordance with the power density calculation procedure of the power double layer capacitor individual standard (EIAJ RC-2379).
[Large current cycle test]
As a durability test, a large current cycle test of 10,000 cycles was performed in a 25 ° C. environment under a lower limit voltage of 1.5 V, an upper limit voltage of 3.0 V, a charge / discharge current value of 1/60 hour rate, and no pause. The amount of discharge energy at the beginning and end of the durability test was compared.
In measuring the capacitance and internal resistance, and during the durability test, the stress was evaluated by applying a stress of 0.1 MPa in the capacitor stacking direction.

  As shown in Table 3, the electric double layer capacitors of Examples 4 to 6 using activated carbon obtained from the raw coal of the present invention are all in capacitance, internal resistance, output density, and energy retention rate. It turns out that it shows an excellent value.

It is a schematic structure perspective view which shows the activated carbon for electric double layer capacitors which concerns on one Embodiment of this invention, or the manufacturing apparatus of the raw coal. It is sectional drawing of the ultra-high temperature superheated steam manufacturing apparatus used for the said manufacturing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Production apparatus of activated carbon for electric double layer capacitor or its raw coal 10 Super high temperature superheated steam production apparatus 13A, B, 15A, B Honeycomb heat storage body (heat storage body)
131 Water vapor flow path 16A, B Burner (heat supply means)
20 Rotary kiln type activation furnace (activation furnace)
21 Rotating cylindrical furnace 22 Heating furnace

Claims (4)

An ultra-high temperature superheated steam production apparatus that heats water vapor to 900 ° C. or higher to form super-high temperature superheated steam, an activation furnace that activates a carbonaceous material with the ultra-high temperature superheated steam obtained by the ultra-high temperature superheated steam production apparatus, An activated carbon for an electric double layer capacitor or a raw coal production apparatus comprising:
The super high temperature superheated steam production apparatus has a heat storage body in which a steam flow path composed of a plurality of cell holes is formed, and a heat supply means for supplying heat to the heat storage body. Production equipment for activated carbon or its raw coal.   A method for producing an activated carbon for an electric double layer capacitor, comprising: activating a carbonaceous material with ultrahigh-temperature superheated steam heated to 900 ° C. or higher to obtain raw coal, and further activating the raw coal.   The manufacturing method of the activated carbon for electric double layer capacitors of Claim 2 which activates the said raw coal with superheated steam below 900 degreeC.   Obtained by an ultra-high temperature superheated steam production apparatus that has a heat storage body in which a water vapor flow path composed of a plurality of cell holes is formed and a heat supply means for supplying heat to the heat storage body and is capable of heating water vapor to 900 ° C. or higher. The obtained super-high temperature superheated steam at 900 ° C. or higher is introduced into an activation furnace, and in this furnace, the carbonaceous material is activated with the ultra-high temperature superheated steam to form a raw material coal, and then is heated in the same activation furnace. The method for producing activated carbon for an electric double layer capacitor according to claim 3, wherein the raw coal is further activated with superheated steam at a temperature of from ℃ to 900 ℃.

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