JP3737162B2 - Method and apparatus for producing activated carbon - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a method for producing activated carbon and a production apparatus for carrying out this method.
[0002]
[Prior art]
Conventionally, when powdered activated carbon is manufactured, in order to maintain an activation temperature of 600 to 1000 ° C., combustion air is supplied or combustion heat due to the use of a burner or the like is used.
Japanese Patent Laid-Open No. 49-128897 discloses that the inside of a fluidized bed type activation chamber connected to the upper side of the working gas / combustion gas chamber is connected in series in the horizontal direction, and the bottom is sequentially formed through the communication hole. It is divided into a plurality of connected chambers, a coking coal feeder is connected to the first (upper) chamber of these multi-stage chambers, and an activated carbon discharge pipe is connected to the last (lower) chamber. An activated carbon production apparatus is described which is connected to perform carbonization and activation simultaneously.
[0003]
[Problems to be solved by the invention]
As described above, in the conventional activated carbon production method and apparatus, an activation furnace is used, and activated carbon is produced by a method of supplying water vapor into a combustion furnace of a pyrolysis gas of auxiliary fuel or activated carbon raw material.
In these conventional methods, since the water vapor concentration is diluted by the combustion exhaust gas, a large activation furnace requiring a slow activation reaction rate and a long residence time is required.
[0004]
The present invention has been made in view of the above points, and the object of the present invention is to activate at a high concentration of 100% without diluting the utilized water vapor so as to advance the activation reaction at high speed and shorten the residence time. The purpose is to make the activation reactor compact.
Another object of the present invention is to integrate a pyrolysis furnace (carbonization furnace) and an activation reactor into a vertical cylindrical main body, and omit a carbonized material transport device and an activated reaction gas transport device. There is.
[0005]
[Means and Actions for Solving the Problems]
In order to achieve the above object, the method for producing activated carbon according to the present invention is a ash in which granular coal is burned with primary air having a theoretical combustion air amount or less in a pyrolysis furnace to leave fixed carbon of the coal, The ash is dropped into an activation reactor as it is, activated with water vapor to form granular activated carbon, and after recovering the amount of heat held in the pyrolysis furnace exhaust gas, a part of the exhaust gas is circulated to the pyrolysis furnace.
In the above method, it is preferable to use water vapor that is heated by a pyrolysis furnace exhaust gas and then further heated by an electric heater as water vapor that activates ash. Moreover, it is preferable to heat the steam that activates the ash with the pyrolysis furnace exhaust gas, and then supply the secondary air to the exhaust gas to generate the steam while burning the unburned components.
[0006]
The primary air supply amount is 30 to 70% of the theoretical combustion air amount of coal. If this value is less than 30%, the amount of combustion of coal is small and the temperature in the pyrolysis furnace tends to be unable to be maintained at 600 ° C. or higher. On the other hand, if it exceeds 70%, combustion to fixed carbon in the coal occurs. Therefore, the carbon to be activated tends to decrease.
Also, the secondary air supply amount so that the total air ratio of the primary air and the secondary air is 1.0 to 1.4, or the oxygen concentration in the exhaust gas is 2 to 5%. To control.
When the total air ratio or oxygen concentration is less than the above range, unburned components remain in the exhaust gas, which tends to be a problem for pollution control. On the other hand, when the total air ratio or oxygen concentration exceeds the above range Tends to be uneconomical due to an increase in the amount of excess combustion air, resulting in poor thermal efficiency.
[0007]
Further, the exhaust gas circulation amount is controlled so that the temperature in the pyrolysis furnace becomes 600 to 1000 ° C. When this value is less than 600 ° C., the thermal decomposition rate is remarkably reduced and operation tends to become impossible. On the other hand, when this value exceeds 1000 ° C., the fixed carbon in the coal melts and cannot be activated. Tend to be.
Furthermore, the amount of water vapor supplied to the activation reactor is controlled so that the temperature in the activation reactor is maintained at 600 to 1000 ° C. When the temperature in the activation reactor is less than 600 ° C, the activation reaction rate is remarkably reduced and the adsorption capacity tends to be small activated carbon. On the other hand, when the temperature exceeds 1000 ° C, the fixed carbon in the coal is melted, There is a tendency that activation reaction does not occur.
[0008]
The activated carbon production apparatus of the present invention supplies a granular cylindrical coal and primary air having a theoretical combustion air amount or less to a vertical cylindrical main body and a substantially central portion of a side portion of the main body to thermally decompose the coal. A pyrolysis furnace provided at a substantially central portion in the main body,
An activation reactor provided at the lower part in the main body for activating the ash with the fixed carbon generated in the pyrolysis furnace dropped, supplying steam and activating,
A steam heater provided in the upper body of the pyrolysis furnace, for heating the steam supplied to the activation reactor with the pyrolysis furnace exhaust gas;
A boiler that is provided in the upper body of the steam heater and generates steam while supplying the secondary air and burning unburned components in the exhaust gas;
An exhaust gas circulation conduit connecting the flue gas flue from the boiler and the pyrolysis furnace;
An electric heater provided in an activated steam supply pipe connecting the steam heater and the activation reactor;
It is characterized by consisting of. In the above-described pyrolysis furnace, it is preferable that the mixed flow of primary air and granular coal is supplied in the tangential direction of the main body to form a swirling flow.
[0009]
【Example】
EXAMPLES Hereinafter, although this invention is demonstrated further in detail based on an Example, this invention is not limited to the following Example at all, It can change suitably and can implement.
Example 1
FIG. 1 shows a flow of a method for producing activated carbon in the present embodiment, and FIG. 2 shows a configuration of an apparatus for producing activated carbon in the present embodiment. Reference numeral 10 denotes a vertical cylindrical main body. An activation reactor 12, a pyrolysis furnace 14, a steam heater 16, and a boiler 18 are formed in series in the main body 10 from below to constitute an apparatus for producing activated carbon. The pyrolysis furnace 14 is provided at a substantially central portion in the main body 10 and supplies granular coal and primary air below the theoretical combustion air amount to a substantially central portion of the side portion of the main body 10 to thermally decompose the coal. Is for. FIG. 2 shows a cyclone-type pyrolysis furnace in which granular coal is supplied in the tangential direction of the main body 10 by primary air to form a swirl flow. Reference numeral 20 denotes a mixing unit for mixing granular coal and primary air.
[0010]
An activation reactor for dropping the ash remaining in the fixed carbon produced in the pyrolysis furnace 14 as it is and supplying the low-pressure steam heated by the steam heater 16 and the electric heater 22 to activate the ash. 12 is provided in the lower part in the main body 10. 24 is a granular activated carbon discharge machine.
A steam heater 16 for heating the low-pressure steam supplied to the activation reactor with the pyrolysis furnace exhaust gas is provided in the main body 10 on the upper side of the pyrolysis furnace 14. In addition, a boiler 18 is provided that generates high-pressure steam while supplying secondary air and burning unburned components in the exhaust gas.
The outlet of the exhaust gas fan 28 of the exhaust gas flue 26 of the boiler 18 and the upper part of the pyrolysis furnace 14 are connected via an exhaust gas circulation conduit 30, and the steam heater 16 and the activation reactor 12 are used for an effective steam supply pipe. The electric heater 22 is provided in the utilization steam supply pipe 32.
[0011]
FIG. 3 is a configuration diagram showing a control mechanism of each part in the activated carbon production apparatus shown in FIG.
Hereinafter, the operation of the present embodiment will be described with reference to FIGS. Powdered coal and primary air of 50 ± 20% of the theoretical combustion air amount are supplied to the pyrolysis furnace (carbonization furnace) 14, and the coal is partially burned at 600 to 1000 ° C. to leave fixed carbon in the coal. This ash is dropped as it is and collected in the activation reactor 12. The temperature in the pyrolysis furnace 14 is configured to be controlled by opening and closing the circulating exhaust gas flow rate control valve 36 provided in the exhaust gas circulation conduit 30 by the temperature indication controller 34 so that the temperature in the pyrolysis furnace 14 becomes 600 to 1000 ° C. The temperature of the circulating exhaust gas is around 200 ° C.
[0012]
The ash in which the fixed carbon in the activation reactor 12 remains is activated with heated low-pressure steam to form granular activated carbon. That is, after low pressure steam of about 0.1 to 0.5 kg / cm ² G and about 150 to 200 ° C. is supplied to the steam heater 16 and indirectly heated to about 600 ° C. in the pyrolysis furnace exhaust gas, Heat to 700 to 1100 ° C. and introduce the heated low pressure steam into the activation reactor 12. And it is comprised so that it can control by opening and closing the heating low pressure steam flow control valve 40 by the temperature instruction | indication controller 38 so that the temperature in the activation reactor 12 may be maintained in the range of 800 +/- 200 degreeC.
[0013]
Secondary air is supplied to the boiler 18 so that the unburned portion in the exhaust gas burns, and becomes high-temperature combustion exhaust gas. And it heat-exchanges with the boiler water introduce | transduced into the boiler 18, and 20-50 kg / cm < ² > G high pressure steam is generated. The high-pressure steam is sent to, for example, a steam turbine (not shown), and the extracted low-pressure steam is sent to the steam heater 16. A portion of the secondary air may be supplied to the steam heater 16, but this is not necessary.
The amount of secondary air supplied to the boiler 18 is adjusted so that the total air ratio combined with the primary air is 1.2 ± 0.2. Instead, an O ₂ meter 42 is provided in the exhaust gas flue 26 so that the secondary air flow rate control valve 44 is opened and closed so that the O ₂ concentration in the exhaust gas becomes 2 to 6%. It is also possible.
[0014]
【The invention's effect】
Since this invention is comprised as mentioned above, there exist the following effects.
(1) By activating at 100% concentration without diluting the activated water vapor, the activation reaction can be advanced at high speed, and the residence time of the granular material in the activation reactor is shortened and the activation reactor. Can be made compact.
(2) Conventionally, the pyrolysis furnace (carbonization furnace) and the activation furnace have been separately provided or separated into separate chambers. However, the apparatus of the present invention has a substantially central portion in a vertical cylindrical body as a pyrolysis furnace. Since the lower part is an activation reactor, the carbonization and activation steps can be performed in an integrated activated carbon production furnace. For this reason, the conveyance apparatus of a carbonization material and activation reaction gas can be abbreviate | omitted.
[Brief description of the drawings]
FIG. 1 is a system diagram showing one embodiment of a method for producing activated carbon according to the present invention.
FIG. 2 is a configuration diagram showing an embodiment of an apparatus for producing activated carbon according to the present invention.
3 is a configuration diagram of an activated carbon manufacturing apparatus in which a control mechanism of each part is added to the apparatus shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Main body 12 Activation reactor 14 Pyrolysis furnace 16 Steam heater 18 Boiler 20 Mixing part 22 Electric heater 24 Powdered activated carbon discharge machine 26 Exhaust gas flue 28 Exhaust gas fan 30 Exhaust gas circulation conduit 32 Utilization water vapor supply pipe 34 Temperature indication controller 36 Control valve 38 Temperature indicating controller 40 Control valve 42 O ₂ meter 44 Control valve

Claims (7)

The particulate coal is burned at the stoichiometric combustion air amount less primary air and ash leaving a fixed carbon of the coal in the pyrolysis furnace, the ash was Do drop in activation reactor, it is heated in the pyrolysis furnace exhaust gas After that , the activated carbon is further activated with steam heated by an electric heater to form granular activated carbon. After recovering the amount of heat held in the pyrolysis furnace exhaust gas, secondary air is supplied to the exhaust gas after heating the steam that activates ash. A method for producing activated carbon characterized in that water vapor is generated while burning unburned components, and part of the exhaust gas is circulated to a pyrolysis furnace . Primary air supply amount, method for producing the activated carbon according to claim 1, wherein 30 to 70% of the theoretical amount of combustion air for coal. As total air ratio is 1.0 to 1.4, or as oxygen concentration in the exhaust gas is 2-6%, the manufacturing method of the activated carbon according to claim 1, wherein for controlling the secondary air supply. The method for producing activated carbon according to claim 1 , 2 or 3 , wherein the exhaust gas circulation amount is controlled so that the temperature in the pyrolysis furnace is 600 to 1000 ° C. The manufacturing method of the activated carbon in any one of Claims 1-4 which controls the quantity of the water vapor | steam supplied to an activation reactor so that the temperature in an activation reactor may be maintained at 600-1000 degreeC.   A substantially central portion in the main body for thermally decomposing coal by supplying granular coal and primary air below the theoretical combustion air amount to a vertical cylindrical main body and a substantially central portion of a side portion of the main body. An activation reactor provided in the lower part of the main body for dropping the ash in which the fixed carbon produced in the pyrolysis furnace is left and supplying steam to activate the pyrolysis furnace provided in A steam heater provided in the main body on the upper side of the pyrolysis furnace, for heating the steam supplied to the activation reactor with the exhaust gas from the pyrolysis furnace, and a secondary body provided in the main body on the upper side of the steam heater A boiler for supplying steam to generate steam while burning unburned components in the exhaust gas, an exhaust gas circulation conduit connecting the exhaust gas flue from the boiler and the pyrolysis furnace, the steam heater, and the activation Electric heat heater installed in the steam supply pipe to connect the reactor Activated carbon production apparatus, wherein the chromatography, in that it consists of. The apparatus for producing activated carbon according to claim 6 , wherein in the pyrolysis furnace, a mixed flow of primary air and granular coal is supplied in a tangential direction of the main body to form a swirling flow.

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