JP2736538B2 - Method and apparatus for firing and activating porous infusibilized pitch granules or carbon granules - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to a method and an apparatus for firing and activating porous infusibilized pitch granules or porous carbon granules. The present invention relates to a method and an apparatus for firing or activating by forming a layer and heating with a heat transfer gas and a heating gas.

[Conventional technology]

It is known to fire and activate porous infusibilized pitch granules and to activate porous carbon granules.

The porous infusibilized pitch granules are, for example, Japanese Patent Publication No. 50-18879
JP, JP-B-51-76, and JP-B-59-10930, a viscosity modifier such as naphthalene is mixed with a petroleum pitch or a coal pitch and melt-formed into granules. Then, the viscosity modifier can be obtained by extraction and removal, and oxidization to make it infusible.

The porous infusibilized pitch particles are usually spherical and can be made into porous carbon particles (activated carbon) by firing and activating. The porous carbon particles obtained by firing or the porous carbon particles having lost the activity can be activated, for example, by raising the temperature to 800 to 1200 ° C. by a steam method.

When the porous infusibilized pitch particles are fired and activated, about 60 to 70% of the particles are gasified. Further, about 40% to 50% of the porous carbon particles obtained by firing the porous infusibilized pitch particles are gasified by simply activating the porous carbon particles. Therefore, conventionally, the moving bed is not adopted because the generated gas is disturbed by the generated gas.
Activation methods and the like were common.

However, both the method using a rotary kiln and the method using a fluidized bed are inferior in furnace volume efficiency and require a large-sized apparatus.

[Problems to be Solved by the Invention] An object of the present invention is to fire or inactivate porous infusibilized pitch granules, or to activate porous carbon granules, and a method with high productivity. It is to provide a device.

The present inventors have conducted intensive studies to solve the problems of the prior art, and as a result, formed a moving layer by using porous infusibilized pitch particles or porous carbon particles, and heating the moving layer from the outside. It has been found that by passing a heating gas through the moving bed in a direction substantially perpendicular to the flowing direction, the baking or activation can be efficiently performed with a relatively small apparatus, and the present invention is completed based on the findings. I came to.

[Means for solving the problem]

 That is, the gist of the present invention is as follows.

(1) A moving layer that flows downward from above is formed by the porous infusibilized pitch particles or the porous carbon particles, and the moving layer is heated from the outside and the flowing direction in the moving layer is substantially the same as the flowing direction. A method for burning or activating porous infusibilized pitch granules or porous carbon granules, characterized by passing a heating gas in an orthogonal direction.

(2) A moving layer that flows downward from above is formed by the porous infusibilized pitch granules or the porous carbon particles, and the moving layer is heated from the outside and the moving layer is stopped flowing down. A porous infusible pitch particle characterized by alternately repeating a step of passing a heating gas through a moving bed in a direction substantially perpendicular to a flowing direction of the moving bed and a step of flowing down the moving bed without passing the heating gas. A method of firing or activating a powder or a porous carbon particle.

(3) A movement in which the inlet (2) for the porous infusibilized pitch granules or the porous carbon granules is provided at the upper part and the extraction port (6) is provided at the lower part, during which the particles flow downward from above. A vertical moving bed heating furnace (1) provided with a layer forming space (3), means for heating the moving bed through a wall surface defining and forming the moving layer forming space (3); A porous infusibilized pitch particle or a porous carbon particle, characterized in that a heating gas inlet and a heating gas outlet for passing a heating gas in a direction substantially perpendicular to the flowing direction are provided through the wall surface. Body firing or activation device.

 Hereinafter, the present invention will be described in detail.

The present invention provides the present invention by flowing a heating gas in a direction substantially perpendicular to a moving direction of a moving layer formed by porous infusibilized pitch particles or porous carbon particles (hereinafter simply referred to as “particles”). Based on finding that the problem is solved.

The method and apparatus of the present invention will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view showing an embodiment of the device according to the present invention, and FIG. 2 is a schematic cross-sectional view taken along the line AA of FIG.

In the vertical moving bed heating furnace (1) shown in FIG. 1, for example, an inlet (2) for granules composed of a valve is provided above the furnace (1), and a discharge port (6) for granules composed of a valve, for example. ) Is provided in the lower part of the furnace (1), and a moving bed forming space (3) for forming a moving bed made of granules flowing downward from above is provided therebetween.

The moving layer formation space (3) is formed, for example, between the outer cylinder (4) and the inner cylinder (5), or by a flat wall, and the thickness of the moving layer is narrower than the length. A vertically long structure is adopted.

Heat sources (7a, 7b) for heating the particles forming the moving layer through the wall surface of the moving layer forming space (3) are provided with the moving layer interposed therebetween. Examples of the heat source (7a, 7b) include an electric heater and a combustion gas. When the combustion gas is used as the heat source, the heating means is provided through the wall of the moving layer forming space (3) with the moving layer interposed therebetween and formed by a passage of the combustion gas.

A cooling means (12) for cooling the particles of the moving layer through the wall surface of the moving layer forming space (3) is provided near the extraction port (6). This cooling means is provided with the moving bed in between.

As shown in FIG. 2, the heating gas introduction line (8A)
A plurality of heating gas inlets (8Aa, 8Ab, 8Ac, ---) penetrating the wall surfaces (4, 5) which define the moving layer formation space (3).
-) And the heated gas discharge line (9A) has the same number of heated gas outlets (9Aa, 9Ab, 9Ac,-
−−), the plurality of pairs of the heated gas inlet and the heated gas outlet are provided at substantially the same height,
In addition, heating gas outlets (9Aa, 9Ac) are provided near a certain heating gas inlet (8Aa), and these heating gas outlets (9Aa
a, 9Ac) and another heated gas inlet (8Ab, 8Ac,
−−−), that is, each heating gas inlet (8Aa, 8Ab, 8Ac, −−−) and a heating gas outlet (9Aa, 9A)
b, 9Ac, ---) are alternately arranged. And
A plurality of pairs of the heating gas inlet and the heating gas outlet are provided at different heights with respect to the moving layer formation space (3). Connected to the discharge line.

Usually, the same number of heating gas inlets and heating gas outlets are provided. In addition, the heating gas inlet and the heating gas outlet located in the moving layer forming space penetrate the wall surfaces (4, 5) that define the moving layer forming space (3), and the heating gas such as a wire mesh is supplied therethrough. It is formed by partition walls (11a, 11b, 11c) having a through-hole which penetrates but does not substantially penetrate the porous infusibilized pitch particles or the porous carbon particles.

By providing the same number of heating gas inlets and heating gas outlets in this way, the stability of the moving bed is not impaired, and the heating gas inlet and heating gas outlet in the moving bed are made porous. By making it a partition consisting of a body,
The dispersibility of the heating gas is improved so that the particles do not flow out of the moving layer formation space (3).

The structure of the moving bed heating furnace (1) may be a two-tower type in which the firing furnace and the activation furnace are separated, or a single-tower type may be used to continuously perform firing and activation. In the case of the double tower type, a sealing mechanism is provided between the firing furnace and the activation furnace, and the apparatus of the present invention is used as a firing furnace and an activation furnace, respectively.

Next, a method of firing or activating the granules using the moving bed heating furnace (1) will be described.

The granules are stored in a hopper (10) provided above the granule inlet (2), and a moving bed is formed from above the heating furnace (1) by opening the granule inlet (2). It flows down into the space (3) to form a moving layer. In the moving layer (3), heating is performed through the wall surface and a heating gas is introduced from a direction substantially perpendicular to the moving layer. However, mixing between the upper and lower particles in the layer and uneven distribution of the heating gas in the layer do not occur. In order to form a stable moving bed, the flow velocity (superficial velocity) of the introduced heating gas is regulated.

In the present invention, firing or activation can be performed while continuously moving the moving layer down.

However, even when the superficial velocity of the heating gas is high to some extent and the pressure in the bed rises, the particles may drift vertically and the moving bed cannot be formed continuously and stably. Separate the time to flow down the moving bed of the body,
That is, when flowing down the moving bed, the heating gas is not flowed so as not to disturb the flow of the granules.On the other hand, when the heating gas is allowed to pass through the moving bed, the flow of the heating gas is stopped after the moving down of the moving bed is stopped. By processing alternately and repeatedly, it is possible to process as a substantially continuous moving layer. The more frequently this repetition is performed, the closer to a complete continuous process, the more the calcined / activated granules having stable quality can be obtained.
In order to temporarily stop the flow of the moving bed, an opening / closing means such as a valve may be provided at the granular material introduction port (2) and the extraction port (6), and the moving bed forming space (3) may be closed.

The temperature of the heat sources (7a, 7b) for heating the particles forming the moving layer through the wall surface of the moving layer forming space (3) is usually 800
~ 1200 ° C, preferably 900 ~ 1100 ° C.

The temperature of the heating gas is 900-1200 ° C, preferably 1000-1
100 ° C.

The superficial velocity of the heating gas in the moving bed depends on the scale of the heating furnace, but is usually preferably 40 cm / sec or less, more preferably 30 cm / sec or less.

When the thickness of the moving layer becomes a certain level or more, a difference in reactivity occurs in the moving layer due to the occurrence of the degree difference, which causes a variation in product quality. It is desirable to make it narrow, and usually it is preferable to make it 50 mm or less.

A heating gas is introduced into the moving bed of the granules through a heating gas introduction line from a number of heating gas inlets formed of a porous body, and sinters or activates the granules. As shown by arrows in FIG. At substantially the same height as the heated gas inlet,
The gas passes through the moving bed in a direction substantially perpendicular to the flowing direction toward the nearest heated gas outlet, and can be discharged together with the gas generated by firing or activation. At that time, the heating gas and the generated gas do not substantially exert a force in the flowing direction of the moving bed, so that the particles do not mix between the upper and lower parts of the moving bed, and are fired or activated while forming a stable moving bed. can do.

The average length from the heated gas inlet to the nearest heated gas outlet at the same height as that,
Defined as "unit length". For example, the unit length in FIG. 2 is such that the heating gas inlets (11b, 11d, 11f) on the outer wall and the inner wall of the moving space (3) respectively extend from the heating gas outlets (11a, 11f).
It is the arithmetic mean of the arc lengths up to 11c, 11e). Also,
If the unit length through which each heating gas passes in the moving bed in a substantially orthogonal direction is too small, the installation of the apparatus becomes complicated, and if it is too large, the pressure inside the moving bed rises, and the moving bed becomes stable. Since the movement (downflow) is impaired, it is preferable that the installation length of the inlet and the outlet of the heating gas in the moving bed is adjusted to a unit length of usually 100 to 400 mm.

The fired or activated granules are supplied to a cooling means (1) provided in the lower part of the moving layer forming space and in the vicinity of the upper part of the extraction port (6).
According to 2), it is cooled by the heat transfer from the wall surface and collected through the outlet (6). As the cooling means, for example, there is a multi-tube heat exchanger. In the case of a two-tower type, it is not always necessary to provide cooling means in one of the heating furnaces.

As will be apparent to those skilled in the art, the size of the heating furnace, the shape of the moving bed formation space, the type of heating means, the number and shape of the heating gas inlet and the heating gas outlet, the type and location of the cooling means For example, the design can be appropriately changed within a range that does not impair the object of the present invention.

〔Example〕

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to only these Examples.

[Example 1] A softening point of 182 ° C generated by naphtha pyrolysis, 100% by weight of a pitch having a quinoline insoluble content of 10% by weight, a hydrogen / carbon atom ratio of 0.53, and 33 parts by weight of naphthalene as a viscosity modifier were heated and melt-mixed. After cooling to 80 to 90 ° C, a string pitch was formed by an extrusion spinning method. This was crushed into a rod-shaped pitch, melted in a 0.4% polyvinyl alcohol aqueous solution heated to 90 ° C., stirred and dispersed, and cooled to form a spherical pitch slurry.

After sieving the particle size of this spherical pitch molded product within the range of 210 μm to 1,000 μm, naphthalene used as a viscosity modifier was extracted with n-hexane. Next, the fluidized bed was heated to 300 ° C. using air to oxidize and infusibilize the fluidized bed.

The porous infusibilized pitch granules obtained in this way are
Outer diameter 400mm, inner diameter 315mm (moving layer thickness 4
Firing and activation were performed in a moving bed heating furnace (firing / activation furnace) with a height of 2.5 mm and a height of 6 m. Heating by heat transfer is performed by the inner heat source (
b), both of the outer heat sources (7a) were controlled by electric heaters, and the heating temperature was controlled at 1,000 ° C on each heater surface. The baking / utilizing gas used was steam heated to 1,000 ° C. outside the system, and the superficial velocity of the heated gas was adjusted within the range of 0.20 to 0.25 cm / sec.

The heated gas inlet and heated gas outlet
A mesh wire mesh was used as a partition. The heating furnace divides the moving bed formation space into three sections at equal intervals in the vertical direction: upper, middle, and lower.
The space for forming the moving layer was divided into six parts in the circumferential direction, and heated gas was introduced into each part from three directions and discharged from three directions.
The unit length through which each heating gas passes in the moving bed in a substantially orthogonal direction is about 170 mm.

When the heating gas is introduced, the valve (2), which is the inlet for the porous infusibilized pitch particles, and the valve (6), which is the outlet, are closed and fired and activated. When the fired and activated product is extracted, heating is performed. The two valves (2,
6) was opened, and the moving bed was allowed to flow down at the same time as extraction. The calcination / activation step was performed for 18 minutes in the reaction time, and the step of letting the moving bed flow down without passing the heating gas was performed at intervals of 2 minutes.

At this time, the time required for the moving bed composed of the porous infusibilized pitch particles to flow down, to be degassed and dehumidified, and to reach the sintering heating section in the moving bed forming space while raising the temperature is about 10 minutes. It took about 10 minutes until the temperature reached 950 ° C. while further flowing down from the container. After reaching 950 ℃, bake
While maintaining the activation temperature, the end of the heating section (the end of the activation section)
The time to reach was about 60 minutes.

At this time, the production amount of the obtained spherical activated carbon per unit time is 62.5 kg / hr, and the throughput per furnace volume is 83 kg / h.
rm ³ . The obtained activated carbon had an average diameter of 600 μm, an activation yield of 42%, an apparent specific gravity of 0.59 g / cc, and an iodine adsorption amount of
The caramel decoloration rate was 1,200 mg / g, and the caramel decoloration rate was 88%. There was no fusion, no deformation cracks, and the surface condition was good.

[Example 2] Using the same porous infusibilized pitch granules and apparatus as in Example 1, the operation was carried out by continuously extracting with a heating gas superficial velocity of 3 to 4 cm / sec. The activation temperature was 950 ° C, and steam at 1000 ° C was used as the heating gas for activation. The production amount of the obtained spherical activated carbon was 10 kg / hr, and the throughput per furnace volume was about 35 kg / hr.m ³ .

The obtained activated carbon had an average diameter of 600 μm, an activation yield of 41%, an apparent specific gravity of 0.58 g / cc, an iodine adsorption amount of 1,220 mg / g, and a caramel decolorization rate of 88%.

Comparative Example 1 The same porous infusible pitch granules as in Example 1 were used,
In a single-stage fluidized bed at 3,450 mm and a total height of about 5 m, an activation gas was maintained at 300 ° C. to 810 ° C. for 15 hours using an activation gas having a composition of steam / nitrogen = 7/3 to obtain spherical activated carbon. The output per unit time was 80 kg / hr, and the throughput per furnace volume was 3.4 kg / hr.m ³ . The obtained activated carbon has an average diameter of 6
The powder had an apparent specific gravity of 0.58, an iodine adsorption amount of 1,200 mg / g, and a caramel decolorization rate of 88%.

Comparative Example 2 The same porous infusible pitch granules as in Example 1 were used,
Steam / two-stage batch fluidized bed of 2,200mm, total height 7,500mm
The temperature was raised from 300 ° C. to 870 ° C. using an activation gas having a composition of nitrogen = 1/1, and then activated at a temperature rising rate of 3 ° C./hr for 4 hours to obtain activated carbon. Production volume per unit time is 140kg /
hr, and the throughput per furnace volume was 7.4 kg / hr.m ³ . The activated carbon obtained has an activation yield of 40% and apparent specific gravity.
It had an iodine adsorption of 1,200 mg / g and a caramel decolorization rate of 88%.

[Effects of the Invention] According to the present invention, there is provided a highly productive method and apparatus for firing or firing porous infusibilized pitch granules or for activating porous carbon granules. be able to. The apparatus of the present invention is smaller than the conventional apparatus, and has remarkably excellent furnace volume efficiency, and can obtain a fired / activated product having the same quality as the conventional method.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the apparatus of the present invention, and FIG. 2 is a schematic sectional view taken along line AA of FIG. 1: Vertical moving bed heating furnace, 2: Granule inlet (valve), 3: Moving bed forming space, 4: Outer cylinder for forming moving bed space, 5: Inner cylinder for forming moving bed space, 6: Granules Extraction ports, 7a, 7b: heat source for heat transfer heating, 8A-8E: heating gas introduction line, 8Aa-8Ac: heating gas introduction port, 9A-9E: heating gas discharge line, 9Aa-9Ac: heating gas discharge port, 10 : Hopper, 11b, 11d, 11f: heated gas inlet in the moving layer forming space, 11a, 11c, 11e: heated gas outlet in the moving layer forming space, 12: cooling means

Claims (8)

(57) [Claims] 1. A moving layer that flows downward from above is formed by porous infusibilized pitch particles or porous carbon particles, and the moving layer is heated from the outside, and the moving layer is placed in the moving layer in the flowing direction. Is a method for firing or activating porous infusibilized pitch particles or porous carbon particles, characterized by passing a heating gas in a substantially orthogonal direction. 2. The method according to claim 1, wherein the passage of the heating gas is performed at a flow rate that does not impair the stability of the moving bed. 3. A moving layer that flows downward from above is formed by the porous infusibilized pitch particles or the porous carbon particles, and the moving layer is heated from the outside and the moving layer stops flowing down. Characterized in that the step of passing a heating gas through the moving bed in a direction substantially perpendicular to the flowing direction thereof and the step of causing the moving bed to flow down without passing the heating gas are alternately repeated. A method of firing or activating pitch particles or porous carbon particles. 4. An inlet (2) for porous infusibilized pitch granules or porous carbon granules at an upper portion and an outlet (6) at a lower portion, during which the granules flow downward from above. A vertical moving bed heating furnace (1) provided with a moving bed forming space (3), wherein the moving bed is heated through a wall surface defining and forming the moving bed forming space (3); Characterized in that a heating gas inlet and a heating gas outlet for allowing a heating gas to pass therethrough in a direction substantially perpendicular to the flowing direction thereof are provided through the wall surface, and the porous infusible pitch particles or the porous An apparatus for firing or activating carbon particles. 5. A means (7a, 7b) for heating the particles through the wall of the moving layer forming space (3) is provided with the moving layer interposed therebetween through the wall surface of the moving layer forming space (3). Item 5. The apparatus according to Item 4. 6. The same number of heating gas inlets (8Aa, 8Ab, 8Ac
−−−) and heated gas outlets (9Aa, 9Ab, 9Ac −−−) are provided alternately in a plurality of pairs at substantially the same height with respect to the moving layer formation space (3), and these heated gas inlets are provided. 5. The apparatus according to claim 4, wherein a plurality of pairs of the heating gas outlets and the plurality of heating gas outlets are provided at different heights with respect to the moving layer forming space (3). 7. A heating gas inlet port and a heating gas outlet port penetrating a wall defining the moving layer forming space (3) and located in the moving layer forming space penetrate the heating gas. 5. The apparatus according to claim 4, wherein the partition wall is formed by a partition wall made of a porous body having a through-hole that cannot substantially penetrate the infusibilized pitch granules or the porous carbon granules. 8. The apparatus according to claim 4, wherein a means (12) for cooling the moving bed through a wall defining the moving bed forming space (3) is provided near the outlet (6).