WO2007119698A1

WO2007119698A1 - Activated carbon, process for producing the same, and production apparatus

Info

Publication number: WO2007119698A1
Application number: PCT/JP2007/057759
Authority: WO
Inventors: Tadashi Yokoi; Ikuyoshi Kohchi; Michio Inagaki
Original assignee: Intellectual Property Bank Corp.
Priority date: 2006-04-10
Filing date: 2007-04-06
Publication date: 2007-10-25
Also published as: JP2009179485A

Abstract

An activated carbon that produced from an organic treatment object, such as a woody material, as a raw material, has a large specific surface area and a pore structure suitable for electric double layer capacitor; and a process for producing the same. There is provided an activated carbon produced by subjecting a treatment object composed mainly of a woody material to carbonization treatment and activation treatment continuously performed in an atmosphere of superheated steam, which activated carbon has a total specific surface area of 600 m2/g or greater and such a pore distribution structure that an external specific surface area occupies 20 to 75% of the total specific surface area.

Description

Specification

Activated carbon, manufacturing method thereof, and manufacturing apparatus

Technical field

[0001] The present invention relates to activated carbon obtained by performing carbonization treatment such as drying, dry distillation, activation, etc. using a woody material as a raw material, a method for producing the same, and a production apparatus.

Background art

Conventionally, as one of the promising candidates for activated carbon used for an electric double layer capacitor electrode, one obtained by carbonizing and activating a petroleum carbon precursor such as a phenol resin can be cited. With regard to such activated carbon, an attempt to suppress the distribution of micropores with a small pore diameter as a pore distribution structure suitable for use in electric double layer capacitors has been made in the field of organic electrolyte type electric double layer capacitors. It has been broken.

[0003] For example, Patent Document 1 discloses activated carbon using an organic electrolytic solution as an electrolytic solution, in which particles of a metal compound having a predetermined particle size are mixed with a petroleum-based carbon precursor, and argon is added. Disclosed is a method for producing activated carbon by heating in an oxidizing gas such as water vapor or carbon dioxide after maintaining the temperature at 700 to 2000 ° C for a long time in a non-oxidizing atmosphere such as nitrogen or nitrogen Has been. The obtained activated carbon is shown to have a force S that the specific surface area based on micropores calculated from the nitrogen adsorption isotherm by the t_plot method is 70% or less of the total specific surface area.

[0004] In addition, in (Patent Document 2), a primary air activation treatment is performed on a carbonized material at 450 ° C. to 550 ° C.:! To 10 hours, and then at 350 to 430 ° C. for 10 hours. A method for producing activated carbon characterized by performing a secondary air activation treatment for ˜60 hours is disclosed. It is shown that the mesopore volume is relatively large and activated carbon is obtained.

[0005] Further, in (Patent Document 3), an alkaline earth metal compound powder is added to a carbonized material such as coatas obtained by heat-treating (sintering) synthetic resin, petroleum-based pitch, or petroleum-based pitch (raw material). A technique for producing a predetermined activated carbon by high-temperature heat treatment is disclosed.

[0006] Patent Document 1: Japanese Patent Application Laid-Open No. 2000-340470

Patent Document 2: JP 2005-286170 A Patent Document 3: Japanese Patent Laid-Open No. 2004-175660

Disclosure of the invention

Problems to be solved by the invention

[0007] However, the methods for producing activated carbon described in (Patent Documents:! To 3) use synthetic resin, coal-based pitch, petroleum-based pitch, etc. as raw materials, all of which do not use woody materials as starting materials. It was a thing. Conventionally, raw materials such as wood materials have performance in order to be used as electric double layer capacitors, which are difficult to control the specific surface area and pore structure compared to synthetic resin, coal-based pitch, petroleum-based pitch, etc. There was a problem that it was difficult to adapt. In addition, (Patent Documents 1 and 3) assume that an organic electrolytic solution having a large ionic diameter is used as the electrolytic solution, and not an aqueous electrolytic solution having a small ionic diameter.

[0008] In view of the above-described conventional situation, the present invention uses a wood material as a raw material, activated carbon having a large specific surface area and a pore structure suitable for an electric double layer capacitor of an aqueous electrolyte, and a method for producing the same The purpose is to provide.

Means for solving the problem

[0009] In order to solve the above problems, the activated carbon of the present invention is manufactured by continuously performing a carbonization treatment and an activation treatment in a superheated steam atmosphere on a treatment object mainly composed of a wood material. The total specific surface area is 600 m ² / g or more, and the outer specific surface area has a pore distribution structure occupying 20% to 75% of the total specific surface area. The total specific surface area was calculated using the α plot method from the amount of nitrogen gas adsorbed on the activated carbon.

S

Represents the surface area per lg of activated carbon. In addition, the external specific surface area is similarly calculated using the α plot method.

S

This is a numerical value calculated by using the surface area per lg of activated carbon for pores with sizes other than micropores (meaning pore diameters of 2 nm or less), and most of the external specific surface area is due to mesopores. .

[0010] Further, the method for producing activated carbon according to the present invention includes a step of drying a treatment object mainly composed of a wood material, and a treatment object dried in the drying step at a temperature of 400 ° C to 950 ° C. Carbonization and activation treatment are continuously performed by retaining in a hot steam atmosphere for a predetermined period of time. * In the carbonization * activation treatment step, the average of superheated steam for performing the activation treatment The temperature is 750 ° C to 900 ° C. In addition, the present invention The activated carbon production method of the present invention is the above-described production method, wherein the carbonization 'activation treatment step is performed when the temperature of the superheated steam at the start of the carbonization activation treatment is 400 ° C to 700 ° C and the carbonization' activation treatment is terminated. The temperature of the superheated steam is 750 ° C to 950 ° C, and the temperature of the superheated steam is increased from the start of the carbonization activation process.

[0011] In addition, the activated carbon production apparatus of the present invention includes a carbonization furnace that includes a water vapor introduction port for introducing superheated water vapor, and performs carbonization treatment and activation treatment on a processing object mainly composed of a wood material. The carbonization furnace is located on the supply port side of a processing object mainly composed of a wood material, and the carbonization part carbonizes the processing object by contacting with the superheated steam; An activation part that is located on the discharge port side of the object to be treated and performs an activation treatment by continuously contacting the object to be treated carbonized in the carbonization part with superheated steam, and the steam inlet is It is characterized in that at least two or more activation parts are provided.

[0012] The activated carbon production apparatus is characterized in that a flow rate control valve for controlling the flow rate of superheated steam is provided at any one or more of the steam inlets.

[0013] In the activated carbon production apparatus, the carbonization section is provided with a low-temperature gas inlet for additionally introducing a gas of 150 to 300 ° C.

[0014] In the activated carbon production apparatus, the carbonization furnace is arranged so as to be inclined downward by 0.1 to 10 degrees from the carbonization part toward the activation part.

[0015] In the activated carbon production apparatus, an inclination angle control device for adjusting the inclination angle of the carbonization furnace is provided.

The invention's effect

[0016] According to the activated carbon of the present invention, a processing object mainly composed of a wood material is used as a raw material, and it has a large specific surface area, and further has a high ratio of the external specific surface area to the total specific surface area. Have. The size of the outer specific surface area greatly contributes to the improvement of the electrostatic capacity of the electric double layer capacitor, and can be suitably used for the electric double layer capacitor. Furthermore, since woody materials are used as starting materials, in recent years they have been released in large quantities in forests, and it is possible to use thinned wood as high-value-added activated carbon such as electrode materials for electric double layer capacitors. It becomes possible. Brief Description of Drawings

[Fig. 1] is an overall configuration diagram of a carbonization device for producing activated carbon for producing activated carbon according to Embodiment (1) of the present invention.

FIG. 2 is a diagram showing a carbonization furnace of a carbonization apparatus for producing activated carbon according to Embodiment (1) of the present invention.

FIG. 3 is a view showing a temperature distribution in the carbonization furnace according to Embodiment (1) of the present invention.

FIG. 4 is a diagram showing a carbonization furnace of a carbonization apparatus for producing activated carbon according to Embodiment (2) of the present invention.

FIG. 5 is a view showing a temperature distribution in the carbonization furnace according to Embodiment (2).

Explanation of symbols

Carbonization equipment for activated carbon production

20 Processing object supply means

22 Hopper

24 conveyor

26 Feeder

30 Drying furnace

31 Cylindrical shell

32 Processing object supply port

33 Cylindrical part

34 Stir blade

35 outlet

36 Steam inlet

37 Water vapor outlet

40 Carbonization furnace

41 Cylindrical shell

42 Processing object supply port

43 Cylindrical part

44 Stirrer blade 46, 46A, 46B, 46C ... Water vapor inlet

47 Water vapor outlet

50 Discharge device

52 Cooling jacket

54 Product tank

56 Screw conveyor

60 High temperature steam generator

62 Blower

64 LPG cylinder

66 Governor

68 Pana

70 Deodorizing furnace

72 Deodorizing furnace blower

74 Kerosene tank

76 Kerosene pump

80 Waste heat boiler

90 Water supply device

92 water softener

94 Soft water tank

95 Water supply pump

96 Dust collector

98 Exhaust pipe

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, the best mode for carrying out the present invention will be described in detail. The activated charcoal of the present invention is manufactured by continuously performing carbonization treatment and activation treatment in a superheated steam atmosphere on a processing object mainly composed of a wood material, and has a total specific surface area of 600 m ² / g or less. Pores with an outer specific surface area of 20% to 75% of the total specific surface area It has a distribution structure. The activated carbon of the present invention preferably has 1000 m ² / g or more, preferably having a total specific surface area of 800 m ² / g or more. The ratio of the outer specific surface area to the total specific surface area is preferably 35% or more and 75% or less, preferably 50% or more75. Particularly preferred is / ₀ or less.

[0020] The present inventors have continuously performed carbonization treatment and activation treatment in a superheated steam atmosphere on an object to be treated mainly composed of a wood material, thereby providing a total specific surface area force S600m ² / The inventors have found that activated carbon having a pore distribution structure having a surface area of g or more and an outer specific surface area of 20% to 75% of the total specific surface area can be produced, and the present invention has been completed. That is, in the activated carbon of the present invention, the outer specific surface area, which is the specific surface area excluding micropores having a pore diameter of 2 nm or less, occupies 20% or more and 75% or less of the total specific surface area, and most of them have a pore diameter. This is due to 2-50 nm mesopores.

[0021] The total specific surface area and the external specific surface area of the activated carbon in the present invention were measured by the following method using a nitrogen adsorption measuring apparatus. The α plot method proposed by Sing was used to calculate the total specific surface area. Specifically, nitrogen gas adsorption at low relative pressure

S

An α plot was created by plotting the amount of nitrogen gas adsorbed against the α value from the quantitative data.

S S

As shown in Equation 1, the α value is the amount of adsorption W at each relative pressure expressed as Ρ / Ρ on the adsorption isotherm.

S

= Indicates the value divided by the amount of adsorption at 0.4 (W = 0.4).

0 Ρ / Ρ0

a = W / W = 0.4 (1)

S P / PO

And based on the created α plot, the total specific surface area S is the origin in the a plot.

S total S

It was calculated from the slope of the straight line that goes up to the right. The outer specific surface area S is a micropore.

ext

Is calculated from the slope of a straight line with a small slope at the top in the plot.

S

It was. The micropore specific surface area S was determined from the total specific surface area S.

micro total

[0022] Further, the activated carbon in the present invention has a specific surface area of 550 m ² / g or more when expressed using BET specific surface area SBET calculated by the BET method. The BET specific surface area was calculated from the amount of nitrogen gas adsorbed on the activated carbon using the BET equation.

[0023] Next, an activated carbon production apparatus for producing activated carbon as described above will be described in detail.

FIG. 1 is an overall configuration diagram of a carbonization apparatus for producing activated carbon according to Embodiment (1) of the present invention. . FIG. 2 is a view showing a carbonization furnace used in a carbonization apparatus for producing activated carbon. As shown in FIG. 1, the carbonization apparatus 10 for producing activated carbon introduces the processing object supply means 20 for supplying raw materials such as wood chips to the drying furnace 30, and the steam discharged from the carbonization furnace 40 to introduce the processing object. Is heated by a drying furnace 30 that performs a drying process for discharging the dried processing target and used steam, and the processing target dried in the drying furnace 30 is supplied and heated from the high-temperature steam generator 60. Carbonization is performed by introducing steam and carbonizing and activating the processing target to discharge carbonized carbon and used water vapor. * Carbonization furnace 40 that performs the activation process and activated carbon carbonized in the carbonization furnace 40 are cooled. And a discharge device 50 for storage.

[0024] Further, the carbonization apparatus 10 for producing activated carbon is discharged from the high-temperature steam generator 60 for generating high-temperature superheated steam supplied from the waste heat boiler 80 and supplied to the carbonization furnace 40, and the drying furnace 30. The deodorizing furnace 70 that heats the impurities contained in the used steam and deodorizes and burns it to discharge high-temperature exhaust, and the high-temperature exhaust gas discharged from the deodorizing furnace 70 heats the water to the high-temperature steam generator 60. Waste heat boiler 80 that generates steam for supply, water supply device 90 that supplies water to the waste heat boiler 80, and exhaust gas after heat exchange in the waste heat boiler 80 after being discharged from the deodorizing furnace 70 A dust collector 96 that collects the dust and moisture contained in the dust using a cyclone, etc., and makes it odorless and smoke-free, and an exhaust pipe 98 that releases the exhausted air after dust collection to the atmosphere, The

[0025] The processing object supply means 20 includes a hopper 22 that stores a raw material processing object such as wood chips, a conveyor 24 that supplies the processing object stored in the hopper 22 to a feeder 26, and a drying furnace. 30 is provided with a feeder 26 for weighing and processing objects.

[0026] In the cylindrical shell 31 of the drying furnace 30, a processing object supply port 32 for supplying the processing object weighed by the feeder 26, a cylindrical part 33 for moving the stirring object while stirring and dry-drying the processing object, Stirring blades 34 such as multiple propeller feeders that can be rotated while stirring and moving the processing object in the cylindrical shell 31 while drying and dry distillation, and an outlet for discharging the dried and dry-distilled processing target 35, a steam inlet 36 for introducing the used steam discharged from the carbonization furnace 40 from the outside of the cylindrical portion 33 in the tangential direction (tangential direction) of the cylinder inner surface in the same direction as the rotation direction of the stirring blade 34, Used steam after heating the processing object in the cylindrical shell 31 from the inner surface of the cylindrical portion 33 to the outer side of the cylindrical portion 33 Water vapor outlet 37 is provided to discharge in the direction (tangential direction).

[0027] In the cylindrical shell 41 of the carbonization furnace 40, a treatment object supply port 42 for supplying the dried treatment object discharged from the discharge port 35 of the drying furnace 30, and the treatment object are carbonized and activated. A cylindrical portion 43 that is stirred and moved, and one or more rotatable screw type compressors, propeller feeders, and the like for moving the object to be stirred while moving in a low oxygen state in the cylindrical shell 41 Of stirring blade 44, discharge port 45 for discharging the carbonized and activated treatment target, and 700 to 920 ° C superheated steam discharged from high-temperature steam generator 60 Rotating stirring blade 44 from the outside of cylindrical part 43 The steam inlet 46 to be introduced in the same direction as the cylinder inner surface tangential direction (tangential direction) and the used steam after heating the processing object in the cylindrical shell 41 from the inner surface of the cylindrical portion 43 to the outer side of the cylindrical portion Tangent direction of inner surface of cylindrical part 43 A water vapor outlet 47 is provided to discharge in the (tangential direction). The rotating shaft of the stirring blade configured to be rotatable is provided so as to be parallel to the cylindrical portion 43. The carbonization furnace 40 is arranged so as to be inclined downward from the processing object supply port 42 toward the discharge port 45, and the inclination angle is preferably 0.1 ° to: 10 °. 0.5. It is particularly preferred that the angle be ˜2 °. Since the carbonization furnace 40 is inclined downward from the treatment object supply port 42 toward the discharge port 45, it is possible to move the treatment object reliably and stably in combination with the movement by the stirring blade 44. It becomes. An angle control device for tilting the carbonization furnace 40 is preferably provided. The cylindrical shell 41 of the carbonization furnace 40 continuously includes a carbonization part that carbonizes a processing object mainly composed of a wood material by contacting with superheated steam, and a processing object carbonized in the carbonization part. In this way, it is classified into an activation part that performs activation treatment by contacting with superheated steam.

At this time, as shown in FIG. 2, since the superheated steam is intensively introduced from one steam inlet 46 provided in the carbonization furnace 40, the steam is directed from the steam inlet 46 to the steam outlet 47. Therefore, the temperature of superheated steam falls. On the other hand, when viewed from the processing object side, the agitation is moved from the processing object supply port 42 toward the discharge port 45, but the temperature of the superheated steam that comes into contact rises toward the discharge port 45. . The temperature of the superheated steam at the treatment object supply port 42 is the carbonization start temperature when the carbonization process is started 400. C ~ 700. C force is preferred, 500. C ~ 650. Ability to be C S Exit 45 The temperature of the superheated steam at the end of the activation process is the end temperature of the activation process at the end of the activation process.

It is preferred to be between 0 ° C and 920 ° C. Particularly preferred is between 800 and 880 ° C. Further, the flow rate of superheated steam or used steam supplied to the carbonization furnace 40 is preferably 5 (m / s) or more in order to promote heat transfer to the object to be treated. However, if it is 20 (m / s) or more, problems such as erosion occur in the parts used in the carbonization furnace 40, so there is an appropriate flow velocity range. The steam inlet 46 is preferably provided with a flow rate control valve that controls the flow rate of superheated steam by adjusting the opening area or the like of the steam inlet by a pressure adjusting mechanism or a throttle.

[0029] The discharge device 50 includes a cooling jacket 52 that cools the activated carbon that has been carbonized and activated in the carbonization furnace 40 with water, and a water-cooled jacket that sends the finished activated carbon to the product tank 54 while cooling the activated carbon. A screw conveyor 56 is provided.

[0030] The high-temperature steam generator 60 introduces steam from the waste heat boiler 80 into an atmosphere in which LPG or the like is burned by a panner to generate superheated steam. The superheated steam generated by the high-temperature steam generator 60 is supplied to the carbonization furnace 40, and activated carbon is generated by dry distillation, carbonization, and activation of the object to be treated.

[0031] The deodorization furnace 70 supplies used steam discharged from the carbonization furnace 40 into a combustion atmosphere such as petroleum parner, and includes ammonia, mercabtan, hydrogen sulfide, methyl sulfide contained in the used steam. Deodorizing and burning impurities such as methyl disulfide, trimethylamine, acetoaldehyde, and styrene, and exhausting high-temperature exhaust.

The waste heat boiler 80 heats water in multiple stages using the high-temperature exhaust discharged from the deodorization furnace 70 to generate steam (dry steam), and supplies the steam to the high-temperature steam generator 60.

[0033] The dust collector 96 collects dust (solid matter, etc.) and water contained in the exhaust gas after being exchanged in the waste heat boiler 80 after being discharged from the deodorizing furnace 70 using a cyclone or the like. At the same time, the smoke-free process is performed. In addition, the exhaust pipe 98 discharges clean exhaust air after dust collection to the atmosphere.

Subsequently, a method for producing activated carbon using the carbonization apparatus 10 for producing activated carbon will be described. First, the deodorizing furnace blower 72 is operated to supply combustion air to the deodorizing furnace 70. next Kerosene is supplied from the kerosene tank 74 to the deodorizing furnace 70 using the kerosene pump 76, and combustion is started. From the deodorizing furnace 70, 800 to 1200 (° C) exhaust is discharged, and this high-temperature exhaust is supplied to the waste heat boiler 80.

[0035] When the temperature of the waste heat boiler 80 rises, the soft water stored in the soft water tank 94 is pumped by the feed water pump 95 via the water softener 92 of the water supply device 90 and supplied to the waste heat boiler 80. The In the latter stage of the waste heat boiler 80, the supplied soft water is heated to a high temperature. Further, it is supplied to the front stage of the waste heat boiler 80 to generate 150 to 300 (° C.) superheated steam (dry steam) and supply it to the high temperature steam generator 60.

[0036] In the high temperature steam generator 60, the blower 62 is operated to supply combustion air to the high temperature water steam generator 60. Next, in order to heat the water vapor, LPG is supplied from the LPG cylinder 64 through the governor 66 to the panner 68 and ignited. Then, the steam of 150 ° C to 300 ° C introduced from the waste heat boiler 80 is further heated to produce superheated steam of 750 ° C to 950 ° C, more preferably 880 ° C to 920 ° C. And then supplied to the carbonization furnace 40.

[0037] On the other hand, a processing object such as a wood material that is a source of activated carbon is put in the hopper 22 of the processing object supply means 20 and stored in advance. The processing object stored in the hopper 22 is supplied to the feeder 26 by the conveyor 24 provided in the processing object supply means 20. The feeder 26 measures and supplies a predetermined amount of processing object to the drying furnace 30 as appropriate.

The processing object is supplied into the processing object supply port 32 force cylindrical shell 31 provided in the cylindrical shell 31 of the drying furnace 30. Since the stirring blade 34 is rotating inside the cylindrical shell 31, the processing object is gradually moved toward the discharge port 35 while being stirred in the cylindrical portion 33 in the cylindrical shell 31.

[0039] It should be noted that the used superheated steam of 750 ° C to 950 ° C discharged from the carbonization furnace 40 from the steam inlet 36 is in the same direction as the rotation direction of the stirring blade 34 from the outside of the cylindrical portion 33. Cylindrical Introduced in the inner tangential direction (tangential direction), generating strong vortices. Therefore, the superheated steam undergoes a reaction such as heat decomposition or hydrolysis without being mixed well with the object to be treated which is stirred and moved by the stirring blade 34.

[0040] The object to be treated is heated, dried, and dry-distilled by the superheated steam, and proceeds through the cylindrical part 33 toward the water vapor outlet 37, and the used superheated steam is circular from the inner surface of the cylindrical part 33. To the outside of the cylinder part, the cylinder part 33 is discharged in the tangential direction (tangential direction) of the inner surface. Here again, since the steam outlet 37 is provided so that the used superheated steam is discharged in the tangential direction of the inner surface of the cylindrical part 33, the swirling flow of the superheated steam in the cylindrical part 33 is maintained, and Keeping the relative flow rate high, promote heat transfer.

[0041] The superheated steam is introduced from the outside of the cylindrical portion 33 at a flow rate of 5 to 20 (m / s) in the tangential direction of the inner surface of the cylinder in the same direction as the rotation direction of the stirring blade 34. Try to generate a vortex. The superheated steam is sprayed from the side surface of the cylindrical portion 33 near the product outlet 35 at a flow rate of 5 to 20 (mZs) in the circumferential tangential direction, and the steam outlet provided near the inlet of the processing object supply port 32 is used. From the outlet 37, it discharges toward the circumferential tangential direction in the same rotational direction as the stirring blade 34. This structure facilitates the transfer of heat to the object to be processed because the steam moves in the reactor while maintaining a large relative velocity with the object to be processed to some extent with a swirling flow. The temperature of the water approaches that of water vapor, and various reactions such as drying and dry distillation are promoted. In addition, it is preferable that the used superheated steam near the processing object supply port 32 or the steam discharge port 37 has a temperature of 250 ° C to 600 ° C. 300 ° C to 500 ° Especially preferred to have a temperature of C. This used water vapor contains harmful substances such as nitrogen compounds and odors. In the deodorizing furnace 70, the harmful water contained in the used water vapor is burned together with kerosene, etc. 800 Upon heating to a temperature of ° C to 1200 ° C, harmful substances are decomposed.

Subsequently, the processing object dried in the drying furnace 30 is discharged from the discharge port 35 and supplied to the carbonization furnace 40 of the next processing step. The object to be processed discharged from the drying furnace 30 is provided in the cylindrical shell 41 of the drying furnace 40 and supplied to the inside of the cylindrical shell 41 through the processing object supply port 42 force. Since the stirring blades 44 are rotating inside the cylindrical shell 41, the processing object is gradually moved toward the discharge port 45 while being stirred in the cylindrical portion 43 in the cylindrical shell 41.

[0043] The superheated steam supplied from the high-temperature steam generator 60 is introduced from the steam inlet 46 into the cylinder inner surface tangential direction (tangential direction) in the same direction as the rotation direction of the stirring blade 44 from the outer side of the cylindrical portion 43. Thus, a strong swirl flow of water vapor is generated. Therefore, the superheated steam is well mixed with the object to be treated that is being stirred and moved by the stirring blade 44. As the process object carbonizes and activates the object to be processed, the cylindrical part 43 advances toward the water vapor outlet 47, and the used water vapor moves from the inner surface of the cylindrical part 34 to the outer side of the cylindrical part. Direction). Here again, the steam outlet 47 is provided so that the used steam is discharged in the tangential direction of the inner surface of the cylindrical part 43, so that a reaction such as thermal decomposition or hydrolysis is promoted while being well mixed with the object to be treated. The

[0044] Next, FIG. 3 shows a temperature distribution in the carbonization furnace according to Embodiment (1) of the present invention.

As shown in Fig. 3, the temperature distribution in the furnace is such that the temperature rises from the treatment object supply port 42 to the discharge port 45 of the carbonization furnace 40 and the temperature of the superheated steam rises from the start to the end of the carbonization activation process. The temperature of the superheated steam is set so that Specifically, the temperature of superheated steam is 400 ° C to 700 ° C in the carbonization part that carbonizes the processing object mainly composed of wood material, and the processing object carbonized in the carbonization part is continuous. It is particularly preferable to set the average temperature of the superheated steam in the activation part to be 750 ° C to 900 ° C, particularly preferably 750 ° C to 850 ° C. Thus, by setting the temperature in the carbonization activation process, activated carbon having a large total specific surface area and a high ratio of the external specific surface area can be obtained. In addition, in order to obtain the temperature of the superheated steam as described above in the carbonization part and the activation part, the temperature of the superheated steam at the processing object supply port 42 when starting the carbonization process is set to 400 ° C to 700 ° C. It is particularly preferable that the temperature of the superheated steam at the outlet 45 at the end of the activation process at 800 ° C to 920 ° C is 800 ° C to 880 ° C. preferable. In addition, the residence time in the activation part, which is carried out after the carbonization of the object to be treated in the apparatus, is preferably about 10 to 30 minutes. If the residence time is insufficient, the generation of pores is insufficient, and if the residence time is too long, the pore size develops too much and the specific surface area may decrease.

Subsequently, activated carbon generated as a result of carbonization and activation in the carbonization furnace 40 is discharged from the discharge port 45 and supplied to the discharge device 50. If high-temperature activated carbon discharged from the carbonization furnace 40 is placed in an oxygen atmosphere, it may be recombusted. Therefore, it is cooled by a cooling jacket 52 provided in the discharge device 50. Further, the activated carbon is cooled and stored in the product tank 54 by a screw conveyor 56 with a water cooling jacket.

[0046] In the above-described embodiment, two of the drying furnace 30 (first reaction furnace) and the carbonization furnace 40 (second reaction furnace) Although the carbonization apparatus for producing activated carbon that performs carbonization treatment such as drying, dry distillation, activation, etc., on the organic processing object using various types of reactors has been described, the present invention uses two types of reactors to carbonize. It is not limited to the example of processing.

[0047] For example, high-temperature superheated steam is generated by using superheated steam that has been heat-recovered from the high-temperature exhaust discharged from the deodorizing furnace 70 in accordance with the type and amount of the object to be treated. Even if superheated steam is introduced into a dry carbonization furnace (first reactor) to dry the object to be treated, it is carbonized and used steam is discharged to achieve the object of the present invention. It is possible.

[0048] Further, a carbonization promotion furnace (third reaction furnace) that introduces superheated steam to promote carbonization of the object to be processed and discharges used steam, and steam discharged from the carbonization promotion furnace is introduced. Carbonization furnace (second reactor) that discharges used steam by carbonizing the object to be processed, and drying that discharges used steam by introducing the steam discharged from the carbonization furnace power and drying the object to be processed Included in the furnace (first reactor), high-temperature steam generator that generates high-temperature superheated steam to introduce steam into the carbonization furnace, and used steam discharged from the drying furnace A deodorizing furnace that heats impurities to deodorize and burn high-temperature exhaust, and a waste that generates water to heat and supply steam to the high-temperature steam generator using the high-temperature exhaust discharged from the deodorizing furnace. A multi-stage reactor is cascaded with a thermal boiler Also it is possible to achieve the purposes of the present invention as active carbon for producing carbide device for carbonizing the treated object by use.

[0049] Next, the carbonization furnace of the carbonization apparatus for producing activated carbon according to Embodiment (2) of the present invention will be described with reference to Figs. FIG. 4 shows a carbonizing furnace of the carbonizing apparatus for producing activated carbon according to the embodiment (2) of the present invention. FIG. 5 shows the furnace temperature distribution in the carbonization furnace according to Embodiment (2).

[0050] In the above embodiment (2), the carbonization furnace 40 is provided with one steam inlet 46 as shown in Fig. 2, but as shown in Fig. 4, the activation part of the carbonization furnace 40 is provided. It is also possible to provide a plurality of steam inlets 46, 46A, 46B only on the side. By providing a plurality of water vapor inlets 46, 46A, 46B in the carbonization furnace 40, it becomes possible to increase the force S to heat the object to be processed to a high temperature in the activation part. In this case, the average superheated steam in the activation part of the carbonization furnace 40 The temperature is preferably 750 ° C to 900 ° C, particularly preferably 750 ° C to 850 ° C. In addition, it is preferable to increase the amount of superheated steam from each of the steam inlets 46, 46A, 46B in the order of the steam inlets 46, 46A, 46B toward the processing object supply port 42 side. As a result, it is possible to more effectively suppress the temperature of the superheated steam supplied from the steam inlet 46, 46A on the discharge port 45 side from dropping in the activation part, and the temperature of the superheated steam in the activation part can be kept constant. . Further, a low temperature gas introduction port 48 for additionally introducing a low temperature gas of 150 to 300 ° C. is provided near the processing object supply port 42 of the carbonization section. By introducing the low temperature gas from the low temperature gas inlet 48, the temperature of the superheated steam in the carbonization part does not rise excessively, and the carbonization of the object to be treated at the initial stage of carbonization can proceed slowly. This makes it possible to perform a uniform carbonization treatment with little bias, and to control the carbonization state to be optimal for producing activated carbon having a large total specific surface area and a high proportion of the outer surface area in the subsequent activation treatment. It becomes possible. In addition, each of these steam inlets 46, 46A, 46B allows superheated steam discharged from the high-temperature steam generator 60 to be tangential to the inner surface of the cylinder in the same direction as the rotation direction of the stirring blade 44 from the outer side of the cylindrical part 43 ( In the tangential direction). If the number of steam inlets is increased more than necessary, the superheated steam flow per steam inlet may be weakened and the swirling flow of superheated steam may be weakened.

Example

Hereinafter, the present invention will be specifically described based on examples.

(Example 1)

• Manufacture of activated carbon

The thinned wood chips that have been processed to a size that can be processed are put into the hopper 22 of the processing object supply means 20 and stored in advance. The processing object stored in the hopper 22 is supplied to the feeder 26 by the conveyor 24 provided in the processing object supply means 20. The object to be treated supplied to the drying furnace 30 is gradually moved in the direction of the discharge port 35 while being agitated by the stirring blade 34 inside the cylindrical shell 31 and dried. Subsequently, the processing object dried in the drying furnace 30 is discharged from the discharge port 35 and supplied to the carbonization furnace 40 of the next processing step, and carbonization and activation are performed. The inside of the carbonization furnace 40 is 80 from the steam inlet 36. Superheated steam at 0 ° C. was introduced, stirred and moved by the stirring blade 34, and subjected to a reaction such as carbonization or activation while being well mixed with the object to be treated. The introduced superheated steam was set so that the average temperature of the superheated steam in the activation process in the carbonization furnace 40 was 760 ° C. The activated carbon produced as a result of carbonization and activation in the carbonization furnace 40 was discharged from the discharge port 45, and the specific surface area, pore structure evaluation, and electric double layer capacitor capacity of the obtained activated carbon were measured.

[0052] (Example 2)

The same procedure as in Example 1 was performed except that the temperature of the superheated steam introduced from the steam inlet was set to 874 ° C and the average temperature of the superheated steam in the activation process in the carbonization furnace 40 was set to 840 ° C. It was.

[0053] (Example 3)

In Example 3, the temperature of the superheated steam introduced from the steam inlet is set to 828 ° C, and a reaction such as carbonization or activation is performed while being well mixed with the processing target being stirred and moved by the stirring blade 34. It is a ί row.

[Example 4]

In Example 4, the temperature of the superheated steam introduced from the steam inlet is set to 832 ° C, and the reaction such as carbonization or activation is performed while being well mixed with the processing target being stirred and moved by the stirring blade 34. It is a ί row.

[Example 5]

In Example 5, the temperature of superheated steam introduced from the steam inlet is set to 849 ° C., and the reaction such as carbonization or activation is performed while being well mixed with the object to be stirred and moved by the stirring blade 34. It is a ί row.

[0056] (Comparative Example 1)

The same procedure as in Example 1 was performed except that the temperature of the superheated steam introduced from the steam inlet was set to 780 ° C and the average temperature of the superheated steam in the activation process in the carbonization furnace 40 was set to 745 ° C. It was.

[0057] (Comparative Example 2)

The temperature of superheated steam introduced from the steam inlet is set to 940 ° C, and the temperature inside the carbonization furnace 40 is increased. The same procedure as in Example 1 was performed except that the average temperature of superheated steam in the active process was 905 ° C.

[0058] · Measurement of specific surface area

The activated carbon produced in each Example and Comparative Example is pulverized in an agate mortar to obtain an activated carbon powder, and the obtained activated carbon powder is heat-treated at 900 ° C. for 1 hour in a nitrogen stream. After that, it was dried in a gas adsorption measurement cylinder at 300 ° C for several hours in a vacuum, and the activated carbon powder was weighed. The activated carbon powder was placed in an aluminum foil container to prevent scattering in a vacuum. And the adsorption curve of high purity nitrogen gas was measured at 77K. Then, the adsorption of nitrogen gas at the nitrogen gas relative pressure PZP <0.3 in the obtained nitrogen gas adsorption curve.

0

From the quantity, the BET specific surface area SBET was measured by a multipoint method.

[0059] · Pore structure evaluation

The specific surface area of the micropore was calculated by the Hi-Plot method proposed by Sing. Low relative

S

Create an α plot from the adsorption data of nitrogen gas at pressure and add it to the created α plot.

S S

Based on this, the total specific surface area S, the outer specific surface area S, and the micropore specific surface area S were determined.

total ext micro

[0060] Table 1 shows data on the specific surface area of the activated carbon obtained in (Examples:! To 5) and (Comparative Examples 1 and 2).

[0061] [Table 1]

As is clear from Table 1, the activated carbons obtained in Examples 1 and 2 have not only a large BET specific surface area and a large total specific surface area, but also the ratio of the external specific surface area to the total specific surface area. 0. 49, 0. 46 and ^ Ξ always large for 0.12, 0.17 respectively I understand.

[0063] · Electric double layer capacitor capacity

The electric double layer capacitor was measured for the activated carbon. For the measurement, using a 3-pole cell, the current density was changed from 50 mA to 1000 mA in 1 MH SO electrolyte, and the current was changed.

twenty four

The flow density was measured. Table 2 shows the measurement results for the activated carbon obtained in Examples 1 and 2. Table 2 also shows the results of measurements on commercially available coconut shell activated carbon for capacitors as Reference Example 1. In addition, the sample for measurement was obtained by mixing activated carbon powder obtained by pulverizing activated carbon in an agate mortar, acetylene black, and PTFE powder at a ratio of 80:10:10 and forming into a film shape. The film thickness used was about 100 mm.

[0064] [Table 2]

[0065] As shown in Table 2, the activated carbons obtained in Examples 1 and 2 and Examples 6 to 9 have a rate performance of 0.63 to 0.77 which is larger than that of commercially available activated carbon. It can be seen that it can be suitably used as an electrode of an electric double layer capacitor. Also, the steam inlet temperature is large (0.71 or more) when the temperature is 800 ° C (Example 1), 874 ° C (Example 2), 887 ° C (Example 8), and 937 ° C (Example 9). ) Activated carbon with Rate Performance is obtained.

Industrial applicability

[0066] This invention uses a wood-based material as a raw material to perform carbonization treatment such as drying, dry distillation, activation, etc. Thus, it can be used for the purpose of producing activated carbon having a large specific surface area and a pore structure suitable for an electric double layer capacitor of an aqueous electrolyte.

Claims

The scope of the claims

[1] Manufactured by continuously performing carbonization treatment and activation treatment in a superheated steam atmosphere on an object to be treated mainly composed of a wood material, and has a total specific surface area of 600 m ² / g or more. An activated carbon having a pore distribution structure in which the outer specific surface area accounts for 20% to 75% of the total specific surface area.

[2] A drying process for drying a processing object mainly composed of a woody material, and the processing object dried in the drying process is held in a superheated steam atmosphere at 400 ° C to 950 ° C for a predetermined time. The carbonization and activation treatment step for continuously performing the carbonization treatment and activation treatment is performed, and in the carbonization and activation treatment step, the average temperature of the superheated steam for performing the activation treatment is 750 ° C to 900 ° C. And a method for producing activated carbon.

[3] In the manufacturing method according to claim 2, in the carbonization 'activation treatment step, the temperature of the superheated steam at the start of the carbonization' activation treatment is 400 ° C to 700 ° C, and the carbonization 'activation treatment is completed. The method for producing activated carbon is characterized in that the temperature of the superheated steam is 800 ° C to 920 ° C and the temperature of the superheated steam is increased until the start of the carbonization activation process.

[4] An activated carbon production apparatus having a steam introduction port for introducing superheated steam, and having a carbonization furnace for performing a carbonization treatment and an activation treatment on a processing object mainly composed of a wood material, the carbonization furnace Is located on the supply port side of a processing object mainly composed of a wood material, and is located on the discharge port side of the processing object, and a carbonization part that carbonizes the processing object by contacting with the superheated steam. And an activation part that performs an activation treatment by continuously contacting the object to be carbonized in the carbonization part with superheated steam, and at least two of the steam inlets are provided in the activation part. Activated carbon production equipment.

[5] The activated carbon production apparatus according to claim 4, wherein a flow rate control valve for controlling the flow rate of superheated steam is provided at any one or more of the water vapor inlets.

[6] The activated carbon production apparatus according to claim 4 or 5, wherein the carbonization furnace is disposed so as to incline downward from 0.1 to 10 ° toward the carbonization part force activation part. Manufacturing equipment.

[7] The activated carbon production apparatus according to claim 6, further comprising an inclination angle control device for adjusting an inclination angle of the carbonization furnace.

[8] The activated carbon production apparatus according to claim 4 or 5, wherein the carbonization section is provided with a low-temperature gas introduction port for additionally introducing a gas of 150 to 300 ° C.

[9] The activated carbon production apparatus according to claim 8, wherein the carbonization furnace is arranged so as to incline downward from 0.1 to 10 ° toward the carbonization part force activation part. .

[10] The activated carbon production apparatus according to claim 9, further comprising a tilt angle control device for adjusting a tilt angle of the carbonization furnace.