JP7152865B2 - Method for producing activated carbon - Google Patents

Description

The present invention relates to a method for producing activated carbon from biomass raw materials such as bamboo and coffee grounds.

Patent Document 1 below describes a step of carbonizing bamboo to obtain carbonized bamboo, and washing the carbonized bamboo so as to remove 20 to 100% by weight of potassium relative to the total amount of potassium contained in the carbonized bamboo. A bamboo activated carbon production method (hereinafter referred to as the first known method) comprising a step of obtaining adjusted bamboo carbonized material and a step of activating potassium adjusted bamboo carbonized material to obtain bamboo activated carbon, and a step of washing the bamboo so that 20 to 100% by weight of potassium is removed by washing the bamboo to obtain a potassium-adjusted bamboo; a step of carbonizing the potassium-adjusted bamboo to obtain a potassium-adjusted bamboo carbide; and a step of activating to obtain bamboo activated carbon (hereinafter referred to as the second known method).

Patent Document 1 discloses that the first and second known methods can produce relatively uniform micropores without being affected by elements such as minerals and component compositions that differ depending on the place of origin, type, growth process, etc. of bamboo. It is possible to easily and inexpensively obtain bamboo activated carbon having It is described that it is possible to obtain bamboo activated carbon that is easily adsorbed.

However, Patent Document 1 only states that potassium can be easily removed by washing with water, acid, or the like, although the method for removing potassium is not particularly limited with regard to washing bamboo or bamboo charcoal. No specific washing method is described.

JP 2007-261918 A

The present invention has been made in view of such prior art, and provides a method for producing activated carbon from a biomass raw material, which is capable of efficiently producing activated carbon having a large specific surface area with well-developed micropores. aim.

In order to achieve the above object, the present invention comprises a step of preparing chip-shaped ash-containing biomass raw material, adding the chip-shaped biomass raw material to washing water in a treatment tank, boiling and cooling, and boiling and cooling. After that, nitric acid is added to the treatment tank, nitric acid cleaning is performed with nitric acid-containing cleaning water, and then the chip-shaped biomass raw material precipitated in the cleaning water is taken out as the washed raw material. Provided is a method for producing activated carbon, including a carbonization step of carbonizing a raw material to obtain a carbide, and an activation step of obtaining activated carbon by performing an activation treatment on the carbide.

Preferably, in the raw material washing step , vibration is applied a predetermined number of times while diluted nitric acid water is added to the washing water .

Preferably, the raw material washing step includes multiple cycles of boiling and cooling.

Preferably, the activation time in the activation step can be set so that the specific surface area of the activated carbon is 1400 m ² /g or more.
More preferably, the activation time can be set so that the specific surface area of the activated carbon is 2000 m ² /g or less.

Preferably, the carbonization step is performed by heating the washed raw material at a temperature of 600° C. or more and 750° C. or less in an atmosphere of superheated steam, and the activation step heats the carbide to a temperature of 750° C. or more and 900° C. in an atmosphere of superheated steam. by heating at the following temperature:

The chip-shaped ash-containing biomass raw material is preferably bamboo chips having a minimum side of 500 μm or more and 2 mm or less in plan view.

According to the method for producing activated carbon according to the present invention, the washing water into which the chip-shaped biomass raw material is charged is boiled and cooled , and after the boiling and cooling, nitric acid is added to the treatment tank and washed with nitric acid-containing washing water. is taken out as a washed raw material, the washed raw material is carbonized to obtain a charcoal, and the charcoal is activated to obtain activated carbon. Therefore, activated carbon with developed micropores and a large specific surface area can be efficiently produced.

FIG. 1 is a front view of an example of a heating device capable of carrying out a carbonization step and an activation step in a method for producing activated carbon according to one embodiment of the present invention. FIG. 2 is a schematic block diagram of the heating device. FIG. 3 is a vertical cross-sectional view of a first heat processing section in the heating device. FIG. 4 is a vertical cross-sectional view of a second heat processing section in the heating device. FIG. 5 is a graph showing the relationship between the activation time and the activation yield in Reference Examples 1 to 4 and Comparative Examples 1 to 4 manufactured according to the embodiment. FIG. 6 is a graph showing the relationship between yield and specific surface area in Reference Examples 1-4 and Comparative Examples 1-3. 7(a) and (b) are graphs showing the frequency distribution of pore diameters in Reference Examples 1 to 4 and Comparative Examples 1 to 3, respectively.

An embodiment of the method for producing activated carbon according to the present invention will be described below.
The method for producing activated carbon according to the present embodiment is a method for producing activated carbon from a biomass raw material containing ash. exemplified.

The method for producing activated carbon has a step of preparing chips of ash-containing biomass raw material.
The size and shape of the chip body are not limited, but considering the cleaning efficiency in the cleaning process described below, the minimum side of the plan view shape can be 2 mm or less.
That is, even if the length of one side of the shape in plan view is 5 cm, if the length of the other side of the shape in plan view is 2 mm or less, the ash can be effectively removed in the cleaning step described below.

Also, considering the activation yield in the subsequent activation step described below, the minimum side of the chip in plan view is preferably 500 μm or more.
That is, when the minimum side of the chip body is less than 500 μm, the activation yield of the product in the activation process is less than 5%, and there is a risk that the product will be in an ash state.

The activated carbon production method further includes a raw material washing step in which the chip-shaped biomass raw material is put into the washing water in the treatment tank, boiled and cooled, and the chip-shaped biomass raw material precipitated in the washing water is taken out as a washed raw material. is doing.

By such a raw material washing process, washing water can be efficiently permeated into the inside of the chip-shaped biomass raw material, and ash can be efficiently removed from the chip-shaped biomass raw material.

For example, ion-exchanged water can be used as the washing water.
The amount of washing water is set so that the entire chip-shaped biomass raw material can be soaked or more. For example, when the chip-shaped biomass raw material weighs M grams and the bulk density of the chip-shaped biomass raw material is D, the amount of washing water can be M/D or more.

The boiling treatment can be performed, for example, by boiling the washing water into which the chip-shaped biomass raw material has been added. The duration for which the boiling state is maintained is not particularly limited, and is appropriately set according to the weight of the chip-shaped biomass raw material.

The cooling treatment can be performed, for example, by cooling the boiled washing water containing the chip-like biomass raw material to room temperature. The cooling method is not particularly limited, and various methods such as natural cooling, water cooling, and air cooling can be used.

Preferably, multiple cycles of boiling and cooling can be performed.

The raw material washing step is preferably configured such that washing water into which the chip-shaped biomass raw material is charged is boiled and cooled, and then the chip-shaped biomass raw material is washed with nitric acid.

In the nitric acid cleaning treatment, after the boiling and cooling treatment, the supernatant water of the cleaning water is discarded, ion-exchanged water is replenished in an amount corresponding to the discarded supernatant water, and nitric acid water is added to the cleaning water in that state. , by leaving it for a predetermined time.
The concentration of nitric acid water is not particularly limited. For example, nitric acid water can be added so that the nitric acid concentration of the washing water is 3 to 10%.

Preferably, vibrations can be applied a predetermined number of times in a state in which the diluted nitric acid water is added to the cleaning water, thereby enhancing the cleaning effect of the nitric acid.

When the raw material washing step includes the nitric acid washing treatment, after the nitric acid washing treatment, the chip-shaped biomass raw material is removed from the washing water containing diluted nitric acid water, and a rinse treatment is performed to remove nitric acid from the chip-shaped biomass raw material with ion-exchanged water. It can be performed.

The activated carbon production method further includes a carbonization step of carbonizing the dried and washed raw material after the raw material washing step.

Although various carbonization methods can be used for the carbonization step, the carbonization step is preferably configured to generate carbide by heating the washed raw material at a temperature of 650° C. or more and 750° C. or less in a superheated steam atmosphere. .

According to such a configuration, carbonization treatment in the carbonization step and activation treatment in the following activation step following the carbonization step are performed by changing only the temperature conditions while using a single superheated steam heating device. be able to.

That is, the method for producing activated carbon further includes an activation step of obtaining activated carbon by performing an activation treatment on the carbide produced in the carbonization step.

Various activation methods can be used for the activation step, but preferably, the temperature is set to 750° C. or more and 900° C. or less in a superheated steam atmosphere using a superheated steam heater that can also be used for carbonization treatment in the carbonization step. is configured to produce activated carbon by heating the carbide at a temperature of

1 and 2 respectively show a front view and a schematic block diagram of Example 1 of a superheated steam heating apparatus capable of carrying out the carbonization step and the activation step.

As shown in FIGS. 1 and 2, the heating device 1 includes a water supply section 90 that supplies steam or water mist, a first heat processing section 100, and a second heat processing section 200. .
In the drawing, reference numeral 10 denotes a frame that supports the carbonization processing section 100 and the activation processing section 200 .

3 and 4 show longitudinal sectional views of the first and second heat processing sections 100 and 200, respectively.

The first heat treatment section 100 is configured to perform a carbonization treatment on an object to be treated (washed raw material).

As shown in FIGS. 2 and 3, the first heating section 100 has a first case body 110, a first screw conveyor 120, and a first superheated steam generating mechanism .

The first case main body 110 is configured to airtightly define a first processing space 110A for receiving a portion to be processed (washed raw material).

In the heating device 1, as shown in FIG. 3, the first case main body 110 has a substantially rectangular upper surface 111 defined by a pair of long sides extending in the longitudinal direction and a pair of short sides extending in the width direction. , a pair of side surfaces 112 extending substantially perpendicularly from a pair of long sides of the top surface 111, a pair of end surfaces 113 extending substantially vertically from a pair of short sides of the top surface 111, lower ends of the pair of side surfaces 112, and the pair of It has a substantially rectangular parallelepiped shape having a bottom face 114 closing the lower end of the end face 113 .

The first screw conveyor 120 is rotationally driven about its axis to convey the object to be processed (washed raw material) in the first processing space 110A from one side to the other in the longitudinal direction of the first processing space 110A. .

As shown in FIG. 3, the first screw conveyor 120 includes a rotating shaft 121 longitudinally traversing the first processing space 110A with at least one end 121a extending outward in an airtight manner; It has a conveying body 122 such as a spiral blade provided on a rotating shaft 121 and an actuator (not shown) such as an electric motor for rotationally driving one end portion 121a of the rotating shaft 121 .

The first screw conveyor 120 includes first and second rotating shafts arranged in parallel to each other as the rotating shaft 121 , and first conveyors provided on the first and second rotating shafts as the carrier 122 , respectively. and a second carrier. In this case, the first and second rotating shafts are synchronously rotated by the actuator.

As shown in FIGS. 2 and 3 , the first superheated steam generating mechanism 130 has a first fluid heating pipe 131 and a first cover case 140 connected to the first case main body 110 .

The first fluid heating pipe 131 is a long hollow member made of a conductive material such as Inconel, Hastelloy, or stainless steel that heats in response to voltage application. Atomized water is received in the internal space and is heated by application of a voltage, thereby converting the steam or the misted water in the internal space into superheated steam and releasing it to the outside.

More specifically, as shown in FIGS. 2 and 3, the first case main body 110 has a receiving port 110 (in) for receiving the object to be processed (washed raw material) to one side of the first processing space 110A, Discharge port 110(out) for discharging the processed material (washed raw material) from the other side of first processing space 110A An upper opening 115 is provided to open 110A upward.

In such a configuration, the first fluid heating pipe 131 is arranged above the first case main body 110 so that the intermediate portion 133 faces the upper opening 115, and the first cover case 140 is arranged to cover the first fluid. It is fixed to the first case main body 110 so as to cover the intermediate portion 133 of the heating tube 131 and airtightly block the upper opening 115 .

More specifically, the first fluid heating tube 131 has a first end 131a on one side in the longitudinal direction and a second end 131b on the other side in the longitudinal direction extending outward from the first cover case 140. The intermediate portion 133 between the first and second ends 131 a and 131 b is arranged to face the upper opening 115 .

The first and second ends 131a, 131b are provided with first and second feeding points 135, 135b, respectively, and one of the first and second ends 131a, 131b is provided with the first feed point 135, 135b. An inlet for introducing steam or water mist from the water supply mechanism 90 is provided in the internal space of the fluid heating pipe 131 .

As shown in FIG. 2 , the water supply unit 90 has a boiler 91 and steam is supplied from the boiler 91 to the introduction port of the first fluid heating pipe 131 .
Reference numeral 92 in FIG. 2 denotes a control valve for adjusting the amount of steam supplied from the boiler 91 to the first fluid heating pipe 131 .

The first fluid heating pipe 131 is heated by applying a voltage to the first and second feeding points 135a and 135b, and converts steam or atomized water in the inner space into superheated steam.
One or more drying outlets (not shown) are provided in the intermediate section 133, and the superheated steam produced by the first fluid heating tube 131 is directed from the one or more drying outlets. It is discharged to the outside and supplied to the first processing space 110A through the upper opening 115. As shown in FIG.

In the heating device 1, as shown in FIG. 3, the first fluid heating pipe 131 is supported by the first cover case 140 via various mounting members, and the first cover case 140 is attached to the first cover case 140 as shown in FIG. By fixing to the upper surface 111 of the case main body 110 , the intermediate portion 133 of the first fluid heating pipe 131 faces the upper opening 115 .

The heating device 1 includes a first temperature sensor (not shown) that detects the temperature of the first processing space 110A, and a control device 300 ( 2), and the control device 300 controls the first superheating so that the temperature in the first processing space 110A reaches a predetermined temperature (600° C. or higher and 750° C. or lower) suitable for carbonization. Voltage application control to the steam generation mechanism 130 is performed.

In the heating device 1, as described above, the first superheated steam generating mechanism 130 is configured to generate superheated steam by the heating action of the first fluid heating pipe 131 in response to voltage application. However, instead of this, the first electromagnetic induction heating in which the first superheated steam generating mechanism 130 heats steam or water mist supplied from the water supply unit 90 by electromagnetic induction to generate superheated steam means (not shown), a first fluid pipe (not shown) to which the superheated steam generated by the first electromagnetic induction heating means is supplied, and a first cover capable of closing the upper opening 115 in an airtight state. It is also possible to configure so as to have a case 140 .

The first electromagnetic induction heating means includes, for example, a first introduction pipe having one end fluidly connected to the water supply unit 90 and the other end fluidly connected to the first fluid pipe; and a first excitation coil wound thereabout.
The first fluid pipe may be arranged such that a predetermined longitudinal portion provided with one or more drying outlets for discharging superheated steam faces the upper opening 115 inside the first cover case 140 .

The second heat processing section 200 is configured to perform an activation process on the material to be processed (carbide) directly or indirectly supplied from the first heat processing section 100 .

The second heat processing section 200 has substantially the same configuration as the first heat processing section 100 .
Specifically, as shown in FIGS. 2 and 4, the second heat processing section 200 has a second case main body 210, a second screw conveyor 220, and a second superheated steam generating mechanism 230. As shown in FIG.

The second case main body 210 is configured to airtightly define a second processing space 210A for receiving the material to be processed (carbide) directly or indirectly supplied from the first heat processing section 100 .

As shown in FIG. 2, the heating apparatus 1 has an intermediate conveying section 50 between the first and second heat processing sections 100 and 200 with respect to the conveying direction of the object to be processed. An object to be processed (carbide) is supplied from the intermediate transfer unit 50 to the heat processing unit 200 .

The intermediate conveying section 50 has an intermediate conveying case 51 defining an airtight conveying space, and an intermediate conveying screw conveyor 52 for conveying the workpiece from one side of the conveying space of the intermediate conveying case 51 to the other side. is doing.

The intermediate carrying case 51 has an intermediate receiving port 51(in) and an intermediate discharging port 51(out) formed to communicate with one side and the other side of the carrying space, respectively. The discharge port 110(out) of the main body 110 is airtightly connected to the intermediate receiving port 51(in) of the intermediate carrying case 51, and the intermediate discharging port 51(out) of the intermediate carrying case 51 is connected to the second case body 210. is airtightly connected to the receiving port 210 (in) of the

The intermediate conveying screw conveyor 52 includes a rotating shaft 52a extending longitudinally through the conveying space with at least one end extending outward, and a conveying body such as a spiral blade provided on the rotating shaft 52a. 52b, and an actuator (not shown) such as an electric motor for rotationally driving one end of the rotary shaft 52a.

As shown in FIG. 4, in the heating device 1, the second case main body 210 has a substantially rectangular upper surface 211 defined by a pair of long sides extending in the longitudinal direction and a pair of short sides extending in the width direction. , a pair of side surfaces 212 extending substantially perpendicularly from a pair of long sides of the top surface 211, a pair of end surfaces 213 extending substantially vertically from a pair of short sides of the top surface 211, lower ends of the pair of side surfaces 212, and the pair of It has a substantially rectangular parallelepiped shape with a bottom surface 214 closing the lower end of the end surface 213 .

The second screw conveyor 220 conveys the object to be processed (carbide) in the second processing space 210A from one side to the other side of the second processing space 210A by being rotationally driven about its axis.

As shown in FIG. 4, the second screw conveyor 220 includes a rotating shaft 221 that longitudinally traverses the second processing space 210A with at least one end extending airtightly outward, and the rotating shaft 221. It has a conveying body 222 such as a spiral blade provided on a shaft 221 and an actuator (not shown) such as an electric motor that rotationally drives one end 221a of the rotating shaft 221 .

As shown in FIGS. 2 and 4 , the second superheated steam generating mechanism 230 has a second fluid heating pipe 231 and a second cover case 240 connected to the second case main body 210 .

The second fluid heating pipe 231 is a long hollow member made of a conductive material such as Inconel, Hastelloy, or stainless steel that heats in response to voltage application. Atomized water is received in the internal space and is heated by application of a voltage, thereby converting the steam or the misted water in the internal space into superheated steam and releasing it to the outside.

More specifically, as shown in FIG. 4, the second case main body 210 includes a receiving port 210 (in) for receiving a material to be processed (carbide) to one side of the second processing space 210A, and a material to be processed (carbide). from the other side of the second processing space 210A, and an upper opening that opens the second processing space 210A upward between the receiving port 210(in) and the discharging port 210(out) in the transport direction. 215 are provided.

In such a configuration, the second fluid heating pipe 231 is arranged above the second case main body 210 so that the intermediate portion 233 faces the upper opening 215, and the second cover case 240 is arranged to cover the second fluid. It is fixed to the second case main body 210 so as to cover the intermediate portion 233 of the heating tube 231 and airtightly block the upper opening 215 .

More specifically, the second fluid heating tube 231 has a first end 231a on one side in the longitudinal direction and a second end 231b on the other side in the longitudinal direction extending outward from the second cover case 240. The intermediate portion 233 between the first and second ends 231 a and 231 b is arranged to face the upper opening 215 .

The first and second ends 231a, 231b are provided with first and second feed points 235a, 235b, respectively, and one of the first and second ends 231a, 231b is provided with the second feed point 235a, 231b. An inlet for introducing steam or water mist from the water supply mechanism 90 is provided in the internal space of the fluid heating pipe 231 .

As described above, in the heating device 1, the water supply unit 90 has the boiler 91, and steam is supplied from the boiler 91 to the introduction port of the second fluid heating pipe 231 (see FIG. 2). .
In addition, reference numeral 92 in FIG. 2 denotes an adjustment valve for adjusting the amount of steam supplied from the boiler 91 to the second fluid heating pipe 231 .

The second fluid heating pipe 231 heats by applying a voltage to the first and second feeding points 235a and 235b, and converts steam or atomized water in the inner space into superheated steam.
The superheated steam generated by the second fluid heating pipe 231 is discharged to the outside from one or a plurality of discharge ports (not shown) provided in the intermediate portion 233, and passes through the upper opening 215 to perform the second treatment. It is supplied to the space 210A.

In addition, in the heating device 1, as shown in FIG. 4, the second fluid heating pipe 231 is supported by the second cover case 240 via various mounting members, and the second cover case 240 is attached to the second cover case 240 as shown in FIG. By fixing it to the upper surface 211 of the two-case main body 210 , the intermediate portion 233 of the second fluid heating pipe 231 faces the upper opening 215 .

The heating device 1 is provided with a second temperature sensor (not shown) that detects the temperature of the second processing space 210A, and the controller 300 detects the temperature in the second processing space 210A. Voltage application control to the second superheated steam generating mechanism 230 is performed so that the predetermined temperature (750° C. or higher and 900° C. or lower) suitable for the treatment is obtained.

In the heating device 1, as described above, the second superheated steam generating mechanism 230 is configured to generate superheated steam by the heat generating action of the second fluid heating pipe 231 in response to voltage application. However, instead of this, the second superheated steam generating mechanism 230 heats steam or mist water supplied from the water supply unit 90 by electromagnetic induction to generate superheated steam. Second electromagnetic induction heating means (not shown), a second fluid pipe (not shown) to which the superheated steam generated by the second electromagnetic induction heating means is supplied, and a second cover capable of closing the upper opening 215 in an airtight state. It is also possible to configure to have a case 240 .

The second electromagnetic induction heating means includes, for example, a second introduction pipe having one end fluidly connected to the water supply section 90 and the other end fluidly connected to the second fluid pipe, and and a second excitation coil wound therearound.
The second fluid pipe may be arranged such that a predetermined longitudinal portion provided with one or more outlets for discharging superheated steam faces the upper opening 215 inside the second cover case 240 .

The control device 300 is configured to be able to set processing conditions including the processing temperatures of the first and second processing spaces 110A and 210A and the conveying speeds of the first and second screw conveyors 120 and 220. The first superheated steam generating mechanism 130, the first screw conveyor 120, the second superheated steam generating mechanism 230, and the second screw conveyor 220 are controlled according to the set processing conditions.

According to the heating device 1, in the first processing space 110A defined by the first case body 110, the object to be processed (washed raw material) is conveyed or stopped. ), the superheated steam generated by the first superheated steam generating mechanism 130 is supplied to the entire first processing space 110A through the upper opening 115 of the first case body 110. of superheated steam can be efficiently supplied.

Further, the first fluid heating pipe 131 that heats in response to voltage application is used, and the intermediate portion 133 of the first fluid heating pipe 131 provided with the one or more discharge ports is the portion of the first case main body 110. Since the upper opening 115 and the intermediate portion 133 are airtightly covered by the first cover case 140 while facing the upper opening 115, the entire first processing space 110A is exposed to a high temperature. In addition to being able to efficiently supply the superheated steam, the temperature in the first processing space 110A can be raised by the heat quantity of the first fluid heating pipe 131 together with the heat quantity of the superheated steam, and good heating efficiency can be obtained. can be done.

Further, according to the heating device 1, in the second processing space 210A defined by the second case body 210, the object (carbide) is heated while being conveyed or stopped. On the other hand, since the superheated steam generated by the second superheated steam generating mechanism 230 is supplied through the upper opening 215 of the second case main body 210, the entire second processing space 210A is heated to a high temperature. Steam can be supplied efficiently.

Furthermore, the second fluid heating pipe 231 that heats in response to voltage application is used, and the intermediate portion 233 of the second fluid heating pipe 231 provided with one or more discharge ports is the second case main body 210. Since the upper opening 215 and the intermediate portion 233 are airtightly covered by the second cover case 240 while facing the upper opening 215, the entire second processing space 210A is heated to a high temperature. In addition to being able to efficiently supply the superheated steam, the temperature in the second processing space 210A can be raised by the heat quantity of the second fluid heating pipe 231 together with the heat quantity of the superheated steam, and good heating efficiency can be obtained. can be done.

Therefore, according to the heating device 1 having such a configuration, it is possible to efficiently and continuously produce good activated carbon from the washed raw material.

As shown in FIGS. 1 to 4 and the like, the heating apparatus 1 is provided with a hopper 20 capable of containing an object to be treated (washed raw material) on the upstream side of the first heating section 100 in the flow direction of the object to be treated. The receiving port 110 (in) of the first case main body 110 is directly or indirectly connected to the outlet of the hopper 20 .

In addition, in the heating device 1, an upstream conveying section 30 is interposed between the hopper 20 and the first heat processing section 100, as shown in FIGS.

The upstream transport unit 30 includes an upstream transport case 31 that defines an airtight transport space, and an upstream transport screw conveyor that transports an object to be processed from one side of the transport space of the upstream transport case 31 to the other side. 32.

The upstream transport case 31 has an upstream reception port 31 (in) and an upstream discharge port 31 (out) formed to communicate with one side and the other side of the transport space, respectively. The outlet of the hopper 20 is airtightly connected to the upstream reception port 31 (in) of the upstream transport case 31, and the upstream discharge port 31 (out) of the upstream transport case 31 is connected to the first case main body 110. It is airtightly connected to the receiving port 110(in).

The upstream conveying screw conveyor 32 includes a rotating shaft 32a that longitudinally traverses the conveying space with at least one end extending outward, and a spiral blade or the like provided on the rotating shaft 32a. It has a body 32b and an actuator (not shown) such as an electric motor that rotationally drives one end of the rotating shaft 32a.

Preferably, as shown in FIGS. 1 and 2, the heating device 1 is provided with an upstream opening/closing valve 40 that directly or indirectly opens/closes the receiving port 110 (in) of the first case body 110 .
By providing the upstream opening/closing valve 40, it is possible to control the input amount of the material to be processed to the first heat processing section 100. As shown in FIG.

Furthermore, by providing the upstream opening/closing valve 40, it is possible to more reliably prevent the inflow of air into the first case main body 110 and effectively maintain the superheated steam atmosphere in the first case main body 110. can.

That is, since the inside of the first case main body 110 is pressurized by the superheated steam discharged from the first fluid heating pipe 131, the first case main body 110 can be operated even if the upstream opening/closing valve 40 is not provided. Although it is possible to prevent the inflow of air from the intake port 110(in) of 110 to some extent, the provision of the upstream opening/closing valve 40 can more reliably prevent the inflow of air.

Preferably, the upstream opening/closing valve 40 can be configured to be opened/closed by an actuator whose operation is controlled by the control device 300 .
In this embodiment, the upstream opening/closing valve 40 connects the upstream discharge port 31 (out) of the upstream transport case 31 and the receiving port 110 (in) of the first case main body 110. inserted into the pipe.

Preferably, as shown in FIGS. 1 and 2, the heating device 1 is provided with a downstream opening/closing valve 60 that directly or indirectly opens/closes the outlet 210 (out) of the second case main body 210. be done.

By providing the downstream opening/closing valve 60, it is possible to more reliably prevent the inflow of air into the second case main body 210 and effectively maintain the superheated steam atmosphere in the second case main body 210. FIG.

That is, since the inside of the second case main body 210 is pressurized by the superheated steam discharged from the second fluid heating pipe 231, the second case main body 210 can be operated even if the downstream opening/closing valve 60 is not provided. Although the inflow of air from the outlet 210(out) of 210 can be prevented to some extent, the inflow of air can be more reliably prevented by providing the downstream opening/closing valve 60. FIG.

Preferably, the downstream opening/closing valve 60 can be configured to be opened/closed by an actuator whose operation is controlled by the control device 300 .
In addition, in the heating device 1 , the downstream opening/closing valve 60 is provided at the outlet 210 (out) of the second case main body 210 .

Furthermore, as shown in FIG. 2, the heating device 1 includes a first exhaust duct 70 having one end communicated with the first processing space 110A, and a first exhaust fan 72 interposed in the first exhaust duct 70. and a forced oxidation device 85 connected to the other end of the first exhaust duct 70 .

One end of the first exhaust duct 70 is provided in the first case main body 110 so as to open outward above a region of the first processing space 110A where the object to be processed (washed raw material) is conveyed. connected to the

With such a configuration, dry distillation gas such as tar generated during the carbonization process by the first heat processing section 200 can be burned by the forced oxidizer 85 and released to the atmosphere.
In this embodiment, the exhaust port of the forced oxidizer 85 is connected to the exhaust duct 75 .

Preferably, the first exhaust fan 72 is configured to be operated and controlled by the controller 300 .

Further, as shown in FIG. 2, the heating device 1 includes a second exhaust duct 80 having one end communicating with the second processing space 210A and the other end connected to the forced oxidizer, and the second exhaust and a second exhaust fan 82 inserted in the duct 80 .

One end of the second exhaust duct 80 is provided in the second case main body 210 so as to open outward above a region of the second processing space 210A where the material to be processed (carbide) is conveyed. Connected to the outlet.

With such a configuration, the dry distillation gas such as tar generated during the activation process by the second heat processing section 200 can be burned by the forced oxidizer 85 and released to the atmosphere.

The heating device 1 includes the first and second heat processing units 100 and 200 arranged in series with respect to the conveying direction of the object to be processed, and the first and second heat processing units 100 and 200 are respectively It is configured to perform a carbonization process and an activation process.

Instead of this, it is also possible to carry out the method for producing activated carbon according to the present embodiment using a heating apparatus having a single common heating section.
In this case, first, the washed raw material is heated to a predetermined carbonization temperature in the common heat treatment section for carbonization, and then the carbide generated in the common heat treatment section is heated to a predetermined activation temperature. Activation treatment can be performed to produce activated carbon.

Here, the results of analysis performed on activated carbon ( reference example) produced by one example of the method for producing activated carbon according to the present embodiment will be described.

The reference example was manufactured by the following manufacturing method.
100 g of bamboo chips having a minimum side of 500 μm to 2 mm in plan view were placed in 2 liters of ion-exchanged water and washed by repeating the cycle of boiling and cooling twice.

The bamboo chips in the state of being precipitated in the ion-exchanged water are taken out as washed bamboo chips, dried in the air at a temperature of 110°C, and then heated at a temperature of 600°C for 60 minutes in a nitrogen atmosphere. produced bamboo charcoal.

Four sets of bamboo charcoal produced in this way were prepared and heated at a temperature of 850° C. for 50 minutes, 70 minutes, 110 minutes, and 130 minutes in a superheated steam atmosphere to produce bamboo activated carbon. (hereinafter referred to as Reference Examples 1 to 4, respectively).

For Reference Examples 1 to 4, the activation yield, which is the ratio of the weight of activated carbon to the weight of charcoal, was measured.
FIG. 5 shows the relationship between activation time and activation yield.
An activation yield of 5% or less means that the product is in an ash state rather than activated carbon.

In addition, the specific surface areas of Reference Examples 1 to 4 were measured with a nitrogen adsorption/desorption measuring device.
FIG. 6 shows the relationship between the yield, which is the ratio of the weight of activated carbon to the weight of the washed raw material, and the specific surface area.

Furthermore, the frequency of the pore diameters formed in Reference Examples 1 to 4 was measured using a nitrogen adsorption/desorption measurement device.
FIG. 7(a) shows the relationship between pore size and frequency.

As a comparative example, four sets of charcoal were produced under the same conditions as the reference example except that no washing treatment was performed, and activated carbon was produced under the same conditions as the reference example except for the activation time.
In the comparative examples, the activation times were 30 minutes, 40 minutes, 50 minutes and 60 minutes, respectively (hereinafter referred to as comparative examples 1 to 4).

FIG. 5 shows the relationship between activation time and activation yield in Comparative Examples 1-4, and FIG. 6 shows the relationship between yield and specific surface area in Comparative Examples 1-3.
In addition, FIG. 7(b) shows the relationship between the pore diameter and the frequency in Comparative Examples 1-3.

As is clear from FIG. 5, in Comparative Example 4 (activation treatment for 60 minutes), the activation yield was 5%, and the product was substantially in an ash state. The activation yield was 20% or more ( Reference Example 4), and the product was in a good state of activated carbon.

Moreover, it can be confirmed from FIG. 6 that the specific surface area of Comparative Example 2 is higher than that of Comparative Example 1, but the specific surface area of Comparative Example 3 is lower than that of Comparative Example 2.
Furthermore, from FIG. 7(b), it can be confirmed that in the comparative example, even if the activation treatment time is lengthened, the frequency of pore diameters does not change so much.
Comparative Example 4 was substantially in an ash state, and it was difficult to measure the frequency distribution of the specific surface area and pore diameter.

On the other hand, in the reference examples , as shown in FIG . As a result, it can be confirmed that the frequency of micropores is slightly increased.

Further, from the graph of Reference Example in FIG. 6, it can be seen that the slope between Reference Examples 2 and 3 is greater than the slope between Reference Examples 1 and 2 and the slope between Reference Examples 3 and 4. I can confirm.

From these, it can be inferred that in the reference example, if the activation time is set so that the specific surface area is 1400 m ² /g or more, the frequency of micropores with an opening diameter of 2 nm or less can be greatly increased.
Furthermore, considering production efficiency, it is preferable to set the activation time so that the specific surface area is 2000 m ² /g or less.

Claims (7)

A step of preparing a chip-like ash-containing biomass raw material;
The chip-shaped biomass raw material is put into the washing water in the treatment tank and boiled and cooled. After the boiling and cooling, nitric acid is added to the treatment tank and washed with nitric acid-containing washing water. A raw material washing step of taking out the chip-shaped biomass raw material precipitated in the
a carbonization step of carbonizing the washed raw material after the raw material washing step to obtain a carbide;
and an activation step of obtaining activated carbon by activating the charcoal. 2. The method for producing activated carbon according to claim 1, wherein in the raw material washing step , vibration is applied a predetermined number of times to a state in which diluted nitric acid water is added to the washing water . 3. The method for producing activated carbon according to claim 1, wherein said raw material washing step includes a plurality of cycles of boiling and cooling. The method for producing activated carbon according to any one of claims 1 to 3, wherein the activation time is set so that the specific surface area of the activated carbon becomes 1400 ^m2 /g or more. 5. The method for producing activated carbon according to claim 4, wherein the activation time is set so that the specific surface area of the activated carbon is 2000 m< ² >/g or less. The carbonization step is performed by heating the washed raw material at a temperature of 600° C. or higher and 750° C. or lower in a superheated steam atmosphere,
The method for producing activated carbon according to any one of claims 1 to 5, wherein the activating step is performed by heating the carbide at a temperature of 750°C or higher and 900°C or lower in a superheated steam atmosphere. The method for producing activated carbon according to any one of claims 1 to 6, wherein the chip-shaped ash-containing biomass raw material is a bamboo chip having a minimum side of 500 µm or more and 2 mm or less in plan view.

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