JP2007186383A - Apparatus and method for producing activated carbon - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an apparatus and method for producing activated carbon which stably produce the activated carbon without loss of sealing property in a gas seal part by preventing corrosion in the gas seal part and clogging of a gas exhaust pipe. <P>SOLUTION: The apparatus for producing the activated carbon comprises: an activation furnace 1 for producing the activated carbon by applying alkali activation to a carbon material; the gas exhaust pipe 7 for exhausting exhaust gas from the activation furnace 1; a water spraying apparatus 6 provided in the gas exhaust pipe 7 and for collecting alkali metal and alkali metal compound contained in the exhaust gas; and a water seal part 8 provided in the gas discharge side distal end part of the gas exhaust pipe 7. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an apparatus for producing activated carbon and a production method.

As an apparatus for producing activated carbon by activating a carbon material using an alkali metal hydroxide, for example, there is one described in Patent Document 1 (Japanese Patent Laid-Open No. 5-306109). Here, a raw material supply unit for supplying a raw material composed of a carbon material and an alkali metal hydroxide (for example, potassium hydroxide, sodium hydroxide, lithium hydroxide, etc.), an activation reaction unit (tunnel) for making the carbon material porous Furnace), cooling section (cooling zone) for cooling reaction products that have become high temperature due to activation reaction, alkali metal deactivation section (water injection chamber, gas) for deactivating active alkali metal by-produced by activation reaction An apparatus comprising a replacement chamber) and a water sealing means has been proposed. It is said that activated carbon having a high specific surface area can be produced by using this apparatus.
JP-A-5-306109

  However, the manufacturing apparatus described in Patent Document 1 is not devised to improve corrosion resistance in the gas exhaust pipe through which the atmospheric gas and the generated gas (exhaust gas) are passed. For this reason, the alkali metal entrained in the gas from the activation reaction part particularly corrodes the gas seal part of the gas exhaust pipe, and if the device is used for a long time, the gas leaks from there over time. was there. In addition, as a result of the fine particles of alkali metal compounds such as alkali metal hydroxide and alkali metal carbonate scattered from the activation reaction part agglomerate and adhere to the low temperature part of the gas exhaust pipe, the pipe diameter is reduced, There was also a problem that combustible gas (generated gas) leaked from the gas seal part due to an increase in internal pressure. Furthermore, when the gas exhaust pipe is blocked, the operation is stopped, and there is a problem that an operation for disassembling the apparatus and removing the blocked object has to be performed.

  The present invention has been made to solve the above problems, and prevents corrosion and gas exhaust pipe blockage in the gas seal portion, and at the same time, stable activated carbon without impairing the gas sealing performance in the gas seal portion. It is an object of the present invention to provide an activated carbon production apparatus and a production method capable of producing the same.

  The present inventors have made extensive studies to solve the above problems. As a result, a moisture spraying device is installed in the gas exhaust pipe, especially in the vicinity of the gas seal, to spray moisture into the exhaust gas, and the scattered alkali metal is converted into alkali metal hydroxide, which is then sprayed into the sprayed moisture. Dissolved in the water sealing device, and alkali metal compounds such as alkali metal hydroxides and carbonates that are scattered are also dissolved in sprayed water and poured into the water sealing device. As a result, the inventors have found that the above problems can be solved, and have completed the present invention.

  That is, the present invention is provided in an activation furnace for generating activated carbon by subjecting a carbon material to alkali activation treatment, a gas exhaust pipe for exhausting exhaust gas from the activation furnace, and the gas exhaust pipe, Production of activated carbon having a moisture spraying device for capturing alkali metals and alkali metal compounds contained in exhaust gas, and a water sealing device provided at a gas discharge side tip of the gas exhaust pipe Device. The manufacturing apparatus preferably has a gas seal portion for preventing the exhaust gas from leaking from the gas exhaust pipe.

  In addition, the present invention generates an activated carbon by performing an alkali activation treatment on a carbon material, and sprays moisture into the exhaust gas at the time of the alkali activation treatment so that an alkali metal and an alkali metal compound contained in the exhaust gas are obtained. After capturing and removing, the exhaust gas from which the alkali metal and the alkali metal compound have been removed is introduced into water.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing apparatus and manufacturing method of activated carbon which can prevent the corrosion in a gas seal part, and obstruction | occlusion of a gas exhaust pipe, and can manufacture activated carbon stably, without impairing the gas sealing performance in a gas seal part. Is provided. The obtained activated carbon can be used as an adsorbent, an electrode material for an electric double layer capacitor, and the like.

  Hereinafter, an example of the best mode for carrying out the present invention will be described.

  FIG. 1 is a schematic configuration diagram illustrating an embodiment of an apparatus for producing activated carbon according to the present invention. However, the present invention is not limited to the configuration shown in FIG. Hereinafter, it demonstrates according to drawing.

  The carbon material is mixed with an alkali metal hydroxide, and the mixture 11 is charged into the activation furnace 1. In the activation furnace 1, the carbon material is subjected to alkali activation treatment to generate activated carbon.

  Here, in the present invention, the furnace type of the activation furnace 1 is not particularly limited, and any type of furnace that can perform the activation process can be used. However, from the viewpoint of efficiently performing the alkali activation treatment, it is preferable to use, for example, a batch-type rotary furnace. By rotating the material in the rotary furnace during the activation process, the carbon material and the alkali metal hydroxide are mixed uniformly, the reaction efficiency is improved, and the activation process can be performed in a short time. Because it becomes.

  Further, as the carbon material, coconut husk, carbonized materials such as coal, mesophase carbonized material prepared from petroleum and coal pitch, petroleum and coal coke, phenolic resin carbonized material, carbon black, fullerene black, carbon fiber, Carbon nanotubes can be used. These can be used alone or as a mixture in which two or more of them are mixed, and those pre-fired before the alkali activation treatment can also be used.

  As for the shape of the carbon material, any shape such as granular or fibrous can be used. When the particle size is too large, a uniform activation reaction becomes difficult if it is too large, and is preferably 10 mm or less, particularly preferably about 1 mm to 1 μm. In the case of a fibrous form, for the same reason, the diameter is preferably 1 mm or less, and particularly preferably about 100 to 0.1 μm. Moreover, as an aspect ratio in the case of fibrous form, it is desirable to set it as 1-10.

  As the alkali metal hydroxide, lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, rubidium hydroxide and the like can be used alone or as a mixture of two or more thereof. As a particle size when using these in a solid state, a commercially available pellet may be used as it is, but from the viewpoint of good mixing with a solid carbon material, the particle size is It is preferable to make it fine, and it is preferable to have a particle size of 500 μm or less. It can also be used in the form of a solution. For example, it may be made into an aqueous solution and mixed with the carbon material.

  The larger the amount of alkali metal hydroxide mixed with the carbon material, the better the mixed state. However, in consideration of economy, it is preferably 1 to 5 parts by weight, particularly preferably 1 part by weight of the carbon material. About 2 parts by mass. However, when the mixed amount of the alkali metal hydroxide is less than 1 part by mass with respect to 1 part by mass of the carbon material, the mixed state is deteriorated and sufficient activation treatment cannot be performed.

  In FIG. 1, the mixture 11 of the carbon material and alkali metal hydroxide charged in the activation furnace 1 is heated and activated by a heater 2 provided around the activation furnace 1, for example. . At this time, the atmosphere in the activation furnace 1 is an inert gas atmosphere. Nitrogen, helium, argon, or the like can be used as the inert gas, but nitrogen is preferably used from an economical viewpoint.

  The heating rate in the activation furnace 1 by the heater 2 is preferably 100 ° C./min or less in order to avoid foaming of the mixture 11 of the carbon material and the alkali metal hydroxide. However, if the rate of temperature increase is too slow, the efficiency of the apparatus will deteriorate, so it is preferably 1 ° C./min or more, more preferably 20 to 5 ° C./min.

  As the final temperature of the activation treatment, if it is too low, the activation reaction does not proceed sufficiently, so it is necessary to set it to 600 ° C. or higher, and even if it exceeds 900 ° C., no significant reaction promoting effect is observed. And Further, the holding time at the final temperature does not need to be specially provided. However, if the holding time is about 5 hours at the maximum, the temperature distribution in the activation furnace 1 is eliminated, and uniform quality activated carbon is obtained. The holding time is preferably about 5 hours at the longest.

  In the temperature raising process and activation process in the activation furnace 1, the mixture 11 of the carbon material and the alkali metal hydroxide mainly produces alkali metal and alkali metal carbonates by various elementary reactions. Generate. Since the alkali metal has a high vapor pressure in the activation temperature range, once the alkali metal is generated, it is accompanied by an inert gas such as nitrogen, helium, or argon supplied to maintain an inert atmosphere. The gas seal part 4 of the gas exhaust pipe is reached, where the gas seal part is eroded and corroded. Here, in the example shown in FIG. 1, the gas seal portion 4 includes a rotating side gas exhaust pipe 3 that is rotating in order to discharge exhaust gas from the rotating activation furnace (batch type rotary furnace) 1. This is a portion where gas is sealed between the fixed side gas exhaust pipe 7 and the fixed side. Here, it rotates between the rotation side gas exhaust pipe 3 and the fixed side gas exhaust pipe 7 through a material having corrosion resistance to the gas generated in the activation furnace 1, for example, a graphite ring packing. It is configured to perform gas sealing while making it possible. Due to such a configuration, the gas seal portion 4 is structurally the most vulnerable to corrosion and corrosion by the alkali metal in the activated carbon production apparatus. In order to make the gas seal more complete, a seal packing 5 may be provided.

  In addition, alkali metal hydroxide as an activator and alkali metal carbonate produced by the activation reaction are solids or melts in the temperature raising process and activation process, but some of them become fine particles. Scatter. As in the case of the alkali metal, the scattered fine particles (scattered matter) are accompanied by an inert gas which is an atmospheric gas, and are aggregated and fixed in a low temperature region of the gas exhaust pipe, particularly in the fixed side gas exhaust pipe 7. When this sticking proceeds, the gas exhaust pipe 7 is blocked, and the apparatus is stopped. When removing the fixed matter, care should be taken in performing the work because an alkali metal may be present in the fixed matter.

  Therefore, in the present invention, as illustrated in FIG. 1, an alkali metal compound such as an alkali metal contained in the exhaust gas and an alkali metal hydroxide or an alkali metal carbonate is included in the gas exhaust pipe 7. A water spray device 6 is provided as a capturing means for capturing water. Here, in order to prevent corrosion of the gas seal portion 4 due to alkali metal, the water spray device 6 has a moisture spray direction in the fixed side gas exhaust pipe 7 near the gas seal portion 4 as shown in FIG. It is preferable to provide the gas seal portion 4 so as to be on the opposite side. More specifically, for example, between the gas discharge end of the rotary side gas exhaust pipe 3 and the gas seal part 4 so that the exhaust gas discharged from the rotary side gas exhaust pipe 3 does not reach the gas seal part 4. A water spray port of the water spray device 6 is provided in between, and the direction of spraying the water sprayed from this water spray port is the direction opposite to the gas seal portion 4, that is, the gas discharge end of the rotating side gas exhaust pipe 3. It is configured so as to be directed toward the water sealing device 8 located on the downstream side. The spray port may be provided at one location, but it is preferable to provide a plurality of locations along the periphery of the fixed-side gas exhaust pipe 7.

  The water sprayed from the water spray device 6 first reacts with the alkali metal in the exhaust gas, and the alkali metal is converted into a hydroxide. In the middle of the sprayed water flowing in the direction of the water sealing device 8 provided on the opposite side of the gas seal portion 4 and downstream of the water spraying device 6, excess water dissolves the hydroxide. Then, it is washed away to the water sealing device 8. Thereby, the alkali metal contained in exhaust gas does not reach the gas seal part 4, and corrosion of the gas seal part 4 by an alkali metal can be prevented.

  On the other hand, alkali metal hydroxides and carbonates which are scattered matter are similarly dissolved in the sprayed water, and are pushed away in the direction of the water sealing device 8 and flow into the water sealing device 8. Thereby, it is possible to prevent alkali metal hydroxide or carbonate, which is a scattered matter, from adhering to the gas exhaust pipe 7 and to prevent the gas exhaust pipe 7 from being blocked.

  With respect to the moisture spraying device 7, if the exhaust gas containing volatilized alkali metal, alkali metal hydroxide and carbonate fine particles can be satisfactorily contacted with the sprayed moisture, The form is not particularly limited, and for example, a water spray device, a water vapor introducing device, or the like can be used. By the water spray from the water spray device 7, exhaust gas from which alkali metal, hydroxide and carbonate fine particles have been removed is introduced into the water seal device 8. By blowing the exhaust gas into the water in the water sealing device 8, the alkali metal, its hydroxide and carbonate remaining in the exhaust gas are further dissolved in the water in the water sealing device 8 and removed. Since the exhaust gas discharged from the water sealing device 8 through the water sealing device gas exhaust pipe 9 may contain a combustible gas, the exhaust gas is further sent to an after burner 12 or the like provided on the rear stage and burned. It is discharged after being treated.

  After the activation reaction, the activated carbon material (activated carbon) is cooled after the heater 2 is de-energized. Here, as an atmosphere in the activation furnace 1 at the time of cooling, it is preferable to set it as an inert atmosphere similarly to the above-mentioned activation process. In addition, there is no restriction | limiting in particular in the temperature fall rate at the time of cooling, Usually, it cools by natural air cooling or forced air cooling from the apparatus exterior.

  After cooling, an active alkali metal by-produced during the activation process, such as Na, adhering to the activated carbon is subjected to a deactivation process (inactivation process). At this time, a reactive gas such as water vapor, carbon dioxide gas, or a mixture thereof is circulated through the activation furnace (batch rotary furnace) 1. For example, when potassium hydroxide is used as an activator to be mixed with the carbon material, metal potassium is by-produced. Therefore, by flowing water vapor, metal potassium is converted to potassium hydroxide, and carbon dioxide gas is By flowing, potassium metal is converted to potassium carbonate, and both form a stable compound form. Until the deactivation (deactivation) of the active alkali metal produced as a by-product is completed, water is sprayed from the moisture sprayer 6 into the gas exhaust pipe 7 as in the activation process. It is desirable.

  Next, for the mixture of the carbon material (activated carbon) and the alkali metal compound after the alkali metal deactivation treatment (deactivation treatment), water injection treatment may be performed in the sense of further completeness, Alternatively, it may be poured into water. Thereby, the alkali metal compound which became a stable compound form by the inactivation treatment is removed, and the activated carbon is recovered.

  As an example of the method for removing the alkali metal compound, washing with water and filtration are effective, but other methods may be used. That is, since the above-mentioned potassium hydroxide or potassium carbonate is water-soluble, it can be easily removed by washing with water. The water used for washing can be filtered water or the like in addition to clean water. If impurities contained in the water are adsorbed on the surface of the activated carbon, the quality of the activated carbon is reduced. It is preferable to wash using distilled water. The washing temperature may be room temperature, but heating to about 80 ° C. is preferable because the washing time is shortened.

  The activated carbon from which moisture has been removed by filtration becomes a product after moisture has been further removed using a dryer or the like.

  Specific examples of the present invention will be described below.

  24 kg of carbon material obtained by carbonizing mesophase pitch at 600 ° C. was pulverized to a particle size of 30 μm to obtain carbon fine powder. To this, 48 kg of potassium hydroxide adjusted to a particle size of 500 μm was added and mixed to obtain a mixture.

  As an example of the present invention, using the activated carbon manufacturing apparatus having the configuration shown in FIG. 1, the mixture was used in a batch-type rotary furnace (activation furnace) in which nitrogen was circulated at a heating rate of 2 ° C./min. The temperature was raised to 0 ° C., and the activation treatment was performed by maintaining for 1 hour.

  In this temperature rising process and activation process, water vapor was introduced by a water spray apparatus in the same manner as described with reference to FIG. Then, it stood to cool naturally and the atmosphere gas was switched from nitrogen to water vapor | steam in the place where the temperature of the mixture became 150 degreeC, and the deactivation process (inactivation process) of the alkali metal was performed. When the atmospheric gas was switched to water vapor, the water vapor supplied by the moisture spraying device was stopped.

  The resulting carbon material (activated carbon) and alkali metal compound mixture was slurried with water and washed. Washing was performed several times using ion-exchanged water, and it was confirmed that the washing solution became neutral (pH = 7). After drying, activated carbon was obtained.

  At this time, the gas seal part and the gas exhaust pipe in the activated carbon production apparatus used for activated carbon production were inspected. As a result, no corrosion in the gas seal portion or the presence of a sticking substance in the gas exhaust pipe was observed.

  As a comparative example, only the introduction of water vapor by the water spraying device was omitted from the above-described example of the present invention, and everything else was the same operation to obtain activated carbon.

  Similarly, the gas seal part and the gas exhaust pipe in the activated carbon production apparatus used for activated carbon production were inspected. As a result, some damage was observed in the graphite ring-shaped packing of the gas seal portion, and a large amount of fixed matter was generated in the stationary side gas exhaust pipe. In addition, it was water-soluble when a part of fixed matter was collect | recovered and investigated.

  From the above, it is possible to prevent the corrosion in the gas seal part and the clogging of the gas exhaust pipe, and at the same time, to provide an activated carbon production apparatus and production method capable of producing activated carbon stably without impairing the gas sealing performance in the gas seal part. The effect of the present invention was confirmed.

It is a schematic block diagram which shows one Embodiment of the manufacturing apparatus of the activated carbon which concerns on this invention.

Explanation of symbols

1 Activation furnace (batch rotary furnace)
2 Heater 3 Rotating side gas exhaust pipe 4 Gas seal part 5 Seal packing 6 Moisture spray device 7 Fixed side gas exhaust pipe 8 Water seal device 9 Water seal device gas exhaust pipe 11 Mixture 12 After burner

Claims (2)

An activation furnace for generating activated carbon by subjecting the carbon material to alkali activation,
A gas exhaust pipe for exhausting exhaust gas from the activation furnace;
A water spray device provided in the gas exhaust pipe for capturing an alkali metal and an alkali metal compound contained in the exhaust gas;
An apparatus for producing activated carbon, comprising: a water sealing device provided at a gas discharge side tip of the gas exhaust pipe. Carbon material is activated by alkali to produce activated carbon,
After spraying moisture into the exhaust gas during the alkali activation treatment to capture and remove the alkali metal and the alkali metal compound contained in the exhaust gas,
A method for producing activated carbon, wherein the exhaust gas after the alkali metal and alkali metal compound are removed is introduced into water.

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