JP4628408B2 - Method for producing alkali-activated charcoal and pulverizing apparatus - Google Patents

Description

  The present invention relates to a method for producing alkali-activated charcoal having a high recovery efficiency of a mixture containing alkali-activated charcoal present in a reaction vessel after activation treatment, and an apparatus for pulverizing a block mixture containing alkali-activated charcoal in this method It is about.

  Activated charcoal is produced from carbonaceous materials such as petroleum coke by activation treatment such as alkali activation and steam activation. Alkaline activation uses an alkali metal compound such as potassium hydroxide as an activator, and activates a carbonaceous substance inside a reaction furnace (for example, see Patent Documents 1 to 4) such as a badge-type reaction furnace or a tunnel furnace. This alkali activation is not a general steam activation such as that the specific surface area of the alkali activated charcoal obtained by the activation can be increased and that the pore distribution of the alkali activated charcoal is easy to control. There are features. This alkali activated charcoal is used for electrode materials, catalyst carriers, adsorbents and the like of electric double layer capacitors, and the demand thereof is increasing.

By the way, when the alkali activation is adopted, the reaction vessel used for the activation treatment will be cooled, and in the reaction vessel after the cooling, alkali activated carbon, alkali metal, alkali metal oxide, alkali metal carbonate, etc. There will be a hard lump mixture. Since alkali activated charcoal is contained in the massive mixture, it is necessary to recover the massive mixture inside the reaction vessel. As a method for this recovery, as disclosed in Patent Document 3 by the present applicant, there is a method of pouring water into a massive mixture. According to the method, since the components binding the alkali activated charcoal in the massive mixture are dissolved in water, the alkali activated charcoal can be recovered.
Japanese Patent Laid-Open No. 2-97414 JP-A-3-294780 JP-A-5-306109 JP 2007-15870 A

  However, in the recovery by water injection, when water is poured into a sufficiently cooled massive mixture, the time for dissolving the components binding the alkali activated carbons becomes long. If the standing time after the water injection is short, the amount of the massive mixture in the container that can be collected decreases, and as a result, the number of water injections tends to increase. Therefore, even if it is the amount of water injection once, the technique which can collect | recover many alkali activated charcoal is desired.

  In view of the above circumstances, the present invention provides a method for producing alkali-activated charcoal excellent in the recovery efficiency of alkali-activated charcoal, and an apparatus for pulverizing a block mixture containing alkali-activated charcoal used in the implementation of this method. Objective.

  The present inventors injected the water into the massive mixture present in the container after performing the alkali activation treatment and the cooling treatment, and not only dissolve the components binding the alkali activated charcoal in the massive mixture, but also in the bulk form. A means for pulverizing the mixture itself has been found, and the present invention has been completed.

  That is, the method for producing alkali-activated charcoal according to the present invention includes an activation treatment step of heating a carbonaceous material and an alkali metal compound charged in a container, and cooling the mixture generated by the heating, whereby the mixture is agglomerated. And a cooling step of pouring water into the massive mixture in the container to pulverize at least a part of the massive mixture, and a recovery step of collecting the pulverized product of the massive mixture. Here, “alkaline activated charcoal” refers to the one in which pores are generated on the surface of the carbonaceous material due to heating performed in the activation treatment step, and the specific surface area and pore volume are increased.

  In order to cause pulverization in the water pouring step, water of 1.0 mass times or more of the alkali metal compound in the activation treatment step is added to the massive mixture in the container having a surface temperature of 75 ° C. or more, and 1 kg of the alkali metal compound. Water may be injected at a rate of 30 g / min or more. In order to further improve the recovery efficiency of the alkali activated carbon, the mass mixture having a surface temperature of 120 ° C. or more is added with water at least 1.5 times the mass of the alkali metal compound by 100 g / kg of the alkali metal compound. It is preferable to inject water at a rate of at least minutes.

  A pulverizing apparatus according to the present invention is for pulverizing a massive mixture in a container produced by heating a carbonaceous material and an alkali metal compound charged in the container and cooling the mixture produced by the heating. And having a mechanism for introducing exhaust gas into the interior and discharging exhaust gas, and pouring water into a water injection chamber capable of accommodating the container, and a massive mixture in the container accommodated in the water injection chamber. And a water injector for pulverizing at least a part of the massive mixture. An apparatus for producing alkali-activated charcoal provided with this recovery device also corresponds to the present invention.

  According to the present invention, water is poured into the massive mixture in the container containing the alkali activated charcoal and the massive mixture is pulverized, so that the alkali activated charcoal can be efficiently recovered.

  Below, based on the manufacturing method of the alkali activated carbon which concerns on this embodiment, the manufacturing method of the alkali activated carbon which concerns on this invention is demonstrated. The manufacturing method of this embodiment includes the following activation treatment process, cooling process, water injection process, and recovery process.

(Activation process)
In the activation process, the carbonaceous material and the alkali metal compound are charged into the container, and the carbonaceous material and the like in the container are heated. The carbonaceous material is activated by the heating. Here, the “activation process” is a process for forming pores on the surface of the carbonaceous material and increasing the specific surface area and the pore volume.

  A carbonaceous material known as an activated carbon raw material can be used as the carbonaceous material of the present embodiment. Moreover, the carbonaceous material to be used is not specifically limited. Examples of carbonaceous materials that can be used in this production method include non-graphitizable carbon such as wood, sawdust, charcoal, coconut husk, cellulosic fiber, synthetic resin (eg, phenol resin, furan resin); pitch (eg, mesophase pitch) ), Coke (for example, pitch coke, needle coke, fluid coke), graphitizable carbon such as polyvinyl chloride, polyimide, PAN; and mixtures thereof. If necessary, carbonized material may be used as a carbonaceous material. The carbonization treatment is a treatment in which a carbonaceous material is placed in an inert gas such as nitrogen at a high temperature (for example, 900 to 1000 ° C.) and carbonization of the carbonaceous material proceeds.

  Examples of the alkali metal compound include hydroxides such as sodium hydroxide, potassium hydroxide, and lithium hydroxide; carbonates such as sodium carbonate, potassium carbonate, and lithium carbonate. One or more of these may be selected, and potassium hydroxide is preferably selected. And the usage-amount of an alkali metal compound is good in it being 0.5-10 times the mass of a carbonaceous substance. The larger the amount used, the larger the specific surface area and average pore diameter of the alkali activated charcoal, and the smaller the amount used, the smaller the specific surface area and average pore diameter of the activated charcoal.

  In addition, when preparing an alkali metal compound in a container, you may use the aqueous solution of an alkali metal compound, in order to fully mix with a carbonaceous substance. The amount of water used at this time is preferably 0.05 to 10 times by mass of the alkali metal compound. When using an aqueous solution of an alkali metal compound, before heating for the activation treatment, heating at a temperature lower than the heating temperature in the activation treatment is performed for the purpose of removing moisture to prevent bumping of moisture in the container. It is preferable to do so.

  Heating for the activation treatment is performed under an inert gas atmosphere such as argon or nitrogen; or under reduced pressure (in a vacuum); Heating is preferably performed at a temperature of about 400 to 900 ° C. The specific surface area and average pore diameter of alkali activated carbon tend to decrease when the heating temperature is low, and tend to increase when the heating temperature is high.

(Cooling process)
In the cooling step, a mixture of activated carbon, alkali metal, alkali metal compound, and the like generated by the activation treatment inherent in the container is cooled. The mixture having a reduced surface temperature is agglomerated. If the surface temperature of this mixture is 300 ° C. or less, it has been confirmed that the mixture is agglomerated, and in this cooling step, cooling is performed to such an extent that the mixture in a molten state in the container becomes a hard surface agglomerated mixture. It is enough to do. However, it is not necessary to make the surface temperature of the block mixture below normal temperature (25 ° C.). This is because, as will be described later, in order to pulverize the massive mixture in the water injection step, it is necessary that the surface temperature of the massive mixture usually exceeds room temperature.

  The cooling mode in this step is not particularly limited. For example, cooling is performed by placing a container containing the mixture under an inert gas atmosphere or under reduced pressure (in a vacuum). The mixture agglomerated by cooling and the container that accommodates the mixture are fixed, so that the agglomerated mixture cannot be taken out from the container as it is.

(Water injection process)
In the water injection step, at least a part of the massive mixture is pulverized by pouring water into the massive mixture in the container. The massive mixture is pulverized by heat generation caused by water injection and rapid foaming, and if this pulverization occurs, the contact area of the massive mixture and water is increased, and the pulverization is accelerated. The heat generation and rapid foaming described above are caused by the reaction of alkali metal, alkali metal oxide, etc. generated by the activation of the carbonaceous material with water (at this time, accompanied by generation of hydrogen gas), and through this reaction. A stable alkali metal hydroxide is generated even in the atmosphere.

  In order to cause pulverization of the massive mixture in the water pouring step, the temperature of the massive mixture, the amount of water to be poured, and the water injection speed are important.

  The pulverization of the massive mixture does not occur when the surface temperature of the mixture is normal temperature. The higher the surface temperature of the massive mixture, the easier it is to pulverize, and the surface temperature should be 75 ° C. or higher. In order to increase the pulverization amount of the massive mixture, the surface temperature is preferably 120 ° C. or higher, and more preferably 145 ° C. or higher. On the other hand, if the surface temperature of the massive mixture is too high, the amount of foaming becomes too large, and this foaming may blow out from the container together with the alkali activated carbon. Therefore, it is desirable that the temperature upper limit at the time of water injection is limited, and the temperature upper limit may be about 400 ° C.

  If the amount of water injection is small, heat generation and rapid foaming to bring the massive mixture to pulverization do not occur, and the amount needs to be appropriately determined. It is advisable to use an amount of water that can pulverize and inactivate the active ingredient (alkali metal element) in the bulk mixture, and the amount of water injection is 1.0 mass times or more of the alkali metal compound used in the activation treatment step. Good to be. A preferable amount of water injection is 1.5 times or more of the alkali metal compound. On the other hand, the upper limit of the water injection amount is not particularly limited, but if the water injection amount is excessive, the crushed material etc. will flow out of the container with foaming, so the water injection amount considering the capacity and shape of the container May be determined as appropriate.

  As for the water injection speed, when the speed is low, pulverization of the massive mixture is difficult to occur. Therefore, rapid water injection is necessary. The water injection rate is preferably 30 g / min or more per 1 kg of the alkali metal compound used in the activation treatment step. In order to increase the pulverization amount, it is preferably 100 g / min or more, and 150 g / min or more. It is more preferable that

  As described above, the surface temperature, the water injection amount, and the water injection speed of the massive mixture affect the pulverization of the mixture. In order to pulverize the lump mixture until all or almost all of the alkali activated charcoal can be recovered with a single water injection, the surface temperature of the lump mixture is 120 ° C. or higher, and the amount of water injected is that of the alkali metal compound used in the activation treatment process. It is preferable that the water injection rate is set to 100 g / min or more per 1 kg of the alkali metal compound used in the activation treatment step.

  Hydrogen gas is generated by water injection into the massive mixture. In order to prevent the explosion due to the oxidation reaction of hydrogen gas, it is preferable to inject water into the massive mixture in a state where the container containing the massive mixture is placed in an inert gas atmosphere such as argon or nitrogen.

  FIG. 1 is a schematic configuration diagram of an example of an apparatus for pulverizing a massive mixture. The illustrated apparatus includes a storage tank 1 that temporarily stores water for pouring water into the massive mixture, and a water injection chamber 4 that is installed below the storage tank 1 and pulverizes the massive mixture. Connected to the upper part of the storage tank 1 is a water supply pipe 1 a that serves as a water supply path to the inside of the storage tank 1. On the other hand, an upper portion of the water injection chamber 4 is provided with a gas introduction pipe 4a for introducing a gas for making the inside of the water injection chamber 4 an inert gas atmosphere, and an exhaust pipe 4b serving as an exhaust passage for the internal gas of the water injection chamber 4. ing.

  The illustrated apparatus is provided with a water injection pipe 2 introduced from the lower part of the storage tank 1 into the water injection chamber 4. The water injection pipe 2 is discharged from the storage tank 1 toward the massive mixture. A flow meter 7 for measuring the flow rate of water and a control valve 3 (for example, an electromagnetic valve) for controlling the flow rate and release of water are provided.

  When pulverizing a massive mixture using the apparatus shown in FIG. 1, first, a container 5 that accommodates the massive mixture 6 is placed inside the water injection chamber 4. Here, as shown in FIG. 1, the upper portion of the container 5 is opened, and a lid 5 a that closes with a part of the opening is provided at the upper end of the container 5. The lid 5a has a through hole for allowing water poured into the central portion to flow into the container 5.

  After the container 5 is arranged inside the water injection chamber 4, an inert gas is introduced into the water injection chamber 4 from the gas introduction pipe 4a until the pulverization of the massive mixture 6 by water injection is completed. Along with this introduction, the gas inside the water injection chamber 4 is released from the exhaust pipe 4b, and the exhaust gas is recovered by a device (not shown).

  After the inside of the water injection chamber 4 becomes an inert gas atmosphere, the control valve 3 is opened, and water is injected from the storage tank 1 to the massive mixture 6. That is, in the illustrated pulverizer, the storage tank 1, the water injection pipe 2, and the control valve 3 serve as a water injection machine. Shortly after the water injection, the reaction between the block mixture 6 and water generates heat and foams, and the block mixture 6 is pulverized by this foaming and the like. While foaming is occurring, the lid 5 a at the upper end of the container 5 suppresses the ejection of water and alkali activated carbon from the container 5.

  The pulverizing apparatus of FIG. 1 described above is an example of an apparatus for realizing the water pouring step in the present embodiment, and as long as it is a pulverizing apparatus having a water injection machine capable of controlling the amount of water injected into the massive mixture, the massive mixture. Can be crushed. In addition, a pulverization apparatus having a water injection machine capable of controlling the amount of water injection can be added to a known alkali activated charcoal production apparatus and replaced with a part of a known alkali activated charcoal production apparatus (for example, It is also possible to replace the water injection chamber of the device of Japanese Patent No. 5-306109.

(Recovery process)
In the recovery step, a mixture of alkali activated charcoal, alkali metal hydroxide, water and the like is discharged from the container to recover the alkali activated charcoal.

  A lump mixture that has not been pulverized may adhere to the inside of the container after the collection step. When a new carbonaceous material activation treatment is performed using such a container, the mass ratio of the alkali metal compound and the carbonaceous material will be different from the planned ratio. Preferably, the bulk mixture is removed completely from within the container.

  The alkali activated carbon recovered by the series of steps up to the above recovery step has an alkali metal hydroxide or the like attached to its surface. Usually, in order to remove this deposit, washing | cleaning and drying of alkali activated carbon are performed. Moreover, the grinding | pulverization and classification process for adjusting the particle size of alkali activated carbon is performed as arbitrary processes.

  The alkali activated charcoal, like the conventionally known alkali activated charcoal, is an adsorbent for compound separation, an adsorbent for compound purification, a gas adsorbent, a water treatment agent, a catalyst carrier, an electrode material for a battery, and an electrode material for an electric double layer capacitor. It can be used for various applications such as.

  The present invention will be described more specifically with reference to the following examples. However, the present invention is not limited to the following examples, and may be appropriately modified and implemented within a range that can meet the purpose described above and below. All of which are within the scope of the present invention.

  A phenolic resin carbide and potassium hydroxide obtained by placing a phenolic resin in a nitrogen stream at 700 ° C. for 2 hours in a stainless steel container having a bottomed rectangular tube shape having a width of 100 mm, a depth of 100 mm, and a height of 100 mm is placed in a nitrogen atmosphere. Inside, activation treatment was performed at 800 ° C. for 2 hours. The mixture in the container was agglomerated by natural cooling after the activation treatment, and after the surface temperature of the mass mixture (temperature measured by a thermocouple) reached a predetermined temperature, ion-exchanged water was poured into the mass mixture. Next, the container was allowed to stand and then inverted to recover the alkali activated carbon. In addition, the amount of the above-mentioned phenol resin carbide, the amount of potassium hydroxide used, the surface temperature (temperature) of the block mixture at the start of water injection, the amount of water injected into the block mixture (water injection amount), the rate of water injection, the pulverization of the block mixture Presence / absence, and the lump mixture standing time (standing time) after water injection are as shown in Table 1 below.

  Table 1 shows the presence / absence of the massive mixture in the container after the recovery of the alkali activated carbon and the remaining amount of the massive mixture. The remaining amount here is calculated by subtracting the previously measured mass of the container from the mass of the container after the recovery of the alkali activated carbon.

The following can be confirmed from the results in Table 1.
(1) In the comparative example, pulverization of the massive mixture did not occur after the water injection, and 105 g of the massive mixture remained in the container after the recovery of the alkali activated carbon. On the other hand, in the Example in which the pulverization of the massive mixture occurred, the residual quantity of the massive mixture was 40% or less than that of the comparative example, and it was confirmed that the recovery efficiency of the alkali activated carbon was excellent.
(2) The temperature (surface temperature of the massive mixture at the start of water injection) is 120 ° C. or higher, the amount of water injection is 1.5 mass times or more of potassium hydroxide, and the water injection rate is 100 g / min or more per kg of potassium hydroxide. In Examples 2 and 5 to 7 that satisfy the water injection conditions, it can be confirmed that the remaining amount of the massive mixture was significantly smaller than in the other examples.

It is a schematic block diagram of an example of the apparatus for grind | pulverizing the block mixture containing alkali activated carbon.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Storage tank 2 Water injection pipe 3 Control valve 4 Water injection chamber 4a Gas introduction pipe 4b Exhaust pipe 5 Container 6 Mass mixture 7 Flowmeter

Claims (5)

An activation treatment step of heating the carbonaceous material and alkali metal compound charged in the container;
Cooling the mixture produced by the heating, and the mixture agglomerates;
A water injection step of pouring water into the massive mixture in the container and pulverizing at least a part of the massive mixture;
And a recovery step of recovering the pulverized product of the massive mixture. An activation treatment step of heating the carbonaceous material and the alkali metal compound charged in the container;
Cooling the mixture produced by the heating, and the mixture agglomerates;
A water pouring step of pouring 1.0 mass times or more of the alkali metal compound at a rate of 30 g / min or more per kg of the alkali metal compound into the massive mixture in the container having a surface temperature of 75 ° C. or more;
And a recovery step of recovering the massive mixture pulverized by the water injection.   In the water pouring step, water of 1.5 mass times or more of the alkali metal compound is poured into the massive mixture in the container having a surface temperature of 120 ° C. or higher at a rate of 100 g / min or more per kg of the alkali metal compound. The manufacturing method of the alkali activated carbon of Claim 2. A pulverizing apparatus for pulverizing a massive mixture in the container produced by heating a carbonaceous material and an alkali metal compound charged in the container and cooling a mixture generated by the heating,
A water injection chamber having a mechanism for introducing exhaust gas into the interior and discharging exhaust gas, and capable of accommodating the container;
A pulverizing apparatus comprising: a water injector for injecting water into a massive mixture in a container accommodated in the water injection chamber and pulverizing at least a part of the massive mixture.   An apparatus for producing alkali-activated charcoal comprising the pulverizing apparatus according to claim 4.

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