JPS5948661B2 - How to regenerate activated carbon - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an energizing activated carbon regeneration method for heating and regenerating waste activated carbon by passing an electric current through the used waste activated carbon that has adsorbed organic matter to generate Joule heat.

Generally, activated carbon used as an adsorbent is reactivated once its surface adsorption reaches a saturated state, and then reused. is being carried out.

According to this method, it is known that reproduction occurs through the following three steps.

That is, (1) a drying step (temperature of 100 to 150°C) to evaporate moisture adhering to activated carbon.

(2) Desorption process in which adsorbed organic matter is decomposed, evaporated, or carbonized into coke (temperature 200-600°C)
.

(3) Activation process (temperature: 800-900°C) in which water vapor is blown into the activated carbon to completely remove the carbonized coke-like organic matter remaining in the activated carbon pores through a water gasification reaction.
.

This process is a common and effective method for regenerating used waste activated carbon.

Furthermore, in the energizing activated carbon regeneration method, waste activated carbon is regenerated through the three steps described above, but in this case, electricity is used as a heat source.

That is, in a regeneration device such as the first illustrated example, electricity is passed through electrodes and a layer of waste activated carbon packed between the electrodes.

This generates Joule heat, which heats the activated carbon for drying and desorption.The steam generated by the steam generator is blown into the activated carbon layer from the bottom of the regenerator to activate the activated carbon.

However, during the drying process in such an energized activated carbon regeneration device, as the moisture in the wet activated carbon evaporates,
The organic matter adhering to the outer surface of the activated carbon turns into a paste, which acts as an adhesive and causes the activated carbon particles to form a lump about the size of a soybean.

As a result, the contact between the generated lumps becomes poor, the current carrying resistance increases, and it becomes difficult for the current to flow, resulting in a decrease in the efficiency of the regeneration work and the inconvenience of not being able to perform sufficient regeneration. The activation process requires a high temperature of 800 to 900° C., and a large amount of electrical energy is required for this purpose, resulting in high costs and a very economical disadvantage, and there are still problems in using it on a large scale.

The present invention aims to eliminate these conventional drawbacks, and the regeneration operation is simple in the energized activated carbon regeneration method, the temperature required for regeneration is lower than that of human blood, and it is economical in that electrical energy can be easily saved. The purpose of this invention is to provide a method for regenerating activated carbon.

The present invention is a method for heating and regenerating waste activated carbon by passing an electric current through the used waste activated carbon that has adsorbed organic matter to generate Joule heat. The activated carbon is compressed to prevent the activated carbon from clumping during the drying process, thereby reducing the electrical resistance of the activated carbon and lowering the voltage applied to the regeneration furnace.

In the method of the present invention, the pressure to compress the activated carbon layer is 0.0
5 kg/crit~5. The pressure is preferably Okg/crit, and even if the organic matter adhering to the outer surface of the activated carbon turns into a paste and becomes a lump, this lump is very brittle and will break apart if you poke it with your fingertip, so the pressure will vary somewhat depending on the capacity. is 0.1 to 1. Okp/cr? A pressure of t is sufficient, and it is convenient to compress by means of a pressurizing mechanism, such as a fluid pressure operating machine or other mechanical pressurizing machine, instead of pressurizing by its own weight using a weight.

To explain the example of the energized activated carbon regeneration device shown in FIG. 1, a gravel layer 4 is provided at the bottom of the activated carbon storage chamber of a regeneration tank 3 having graphite electrodes 1, 1 connected to a power source 2, and waste activated carbon 5 is filled above this layer. A channel 6 opened in the gravel layer 4 is connected to a steam generating section 7 so that steam generated by a heating source 8 is fed into the waste activated carbon 5, and electricity is supplied to the electrodes. Joule heat is generated by passing through the waste activated carbon layer packed between the electrodes 1 and 1, which heats the activated carbon, dries and desorbs it, and the steam generated by the steam generator is sent from the bottom of the regenerator. Blow into the activated carbon layer to activate the activated carbon.

At this time, a weight 10 is placed on the activated carbon layer and the activated carbon layer is compressed by its own weight.

That is, as shown in FIG. 2, waste activated carbon 5 is filled between electrodes 1 having ventilation holes 11, and treated under pressure with a concrete weight 10 weighing 100 to 250 kg.

Note that a direct or alternating current, for example, electric field strength of 3 to 30 V/CrIL and current density of 0.
When carried out under the conditions of 05 to 3 A/ff for 1 hour and 10 to 120 minutes, Joule heat is easily generated due to the electrical resistance of the activated carbon, and the activated carbon 5 is heated by self-heating.

Furthermore, as for the water vapor blown into the waste activated carbon 5, it is effective to supply approximately 5 to 200% of the amount, but along with the water vapor, nitrogen and other gases effective for the water gasification reaction, such as carbon dioxide gas, are also fed. In some cases, the gas atmosphere is controlled by

Further, the start-up control of the steam generating section 7 can be automatically performed using the activated carbon temperature detector 9, or can be adjusted by opening and closing a control valve in a conduit that becomes the flow path 6.

The waste activated carbon 5 is regenerated in this way, but the waste gas generated during the regeneration is discharged from the upper part of the regeneration tank 3, and the temperature of the waste activated carbon 5 is directly measured by the temperature detector 9. Control can be carried out directly by controlling the current flowing by controlling the voltage with a controller such as a slider placed between the power source and the wire.

In the figure, 9 is a temperature sensor, and it is reasonable to automatically control the temperature using a detection signal.

Next, examples of the present invention will be shown.

Reproduction was performed using a reproduction device as shown in FIG.

Further, FIG. 2 shows a sectional view of the regeneration furnace used.

The inner dimensions of the regeneration furnace are 50crrL x 50crIl x 50
Its capacity in Confucian terms is 1251.

A regeneration experiment was carried out by placing a concrete weight as shown in the figure above the activated carbon layer.

The activated carbon used was used for advanced treatment of human waste and was spherical with an average particle size of 1.12 mm.

The relationship between the weight of the weight placed on the activated carbon layer and the maximum resistance value due to the agglomeration of activated carbon in the activated carbon drying process is as shown by the solid line in Figure 3, and the relationship between the weight of the weight and the maximum applied voltage at this time. The relationship is as shown by the dotted line in FIG.

As can be seen from the figure, 0.05 kg/kg was particularly effective in reducing the resistance of activated carbon and lowering the applied voltage.
This was the case when a pressure higher than crA was applied.

Note that good results can also be obtained by treating the waste activated carbon by immersing it in an oxygen acid aqueous solution with strong oxidizing power in advance.

For example, one or more of sulfuric acid, nitric acid, chloric acid, perchloric acid, phosphoric acid, etc. may be used in combination or sequentially, and the temperature of these aqueous solutions should be 0.02 mol to 1.0 mol, preferably 0.1 to 1.0 mol.
It is preferable to treat the waste activated carbon in a range of 0.2 mol, and the immersion time of the waste activated carbon is preferably at least 10 minutes or more, preferably 30 minutes or more.

In this case, the oxygen-acid aqueous solution is treated at room temperature, but it may be treated at, for example, 10 to 100°C.

Furthermore, the soaking time for waste activated carbon varies depending on the size of the surface area of the active bank, but it is sufficient as long as it can effectively penetrate into the activated carbon.The time can be shortened by adding a means to increase permeability, such as vibration, during soaking. It is also effective to pre-treat the rotted activated carbon by mechanically deliquifying it after soaking.

In the method of the present invention, in the energized activated carbon regeneration method, by applying pressure to the activated carbon layer during energization, it is possible to reduce the energization resistance of the activated carbon and lower the applied voltage to the regeneration furnace, thereby reducing the power required for regeneration. It can be regenerated extremely efficiently and saves energy, and it is also useful because it can be processed without requiring sophisticated technology or expense, and the amount of processing can be large and efficiently carried out, depending on the operating conditions. It also simplifies process control.

[Brief explanation of the drawing]

Figure 1 is a system explanatory diagram showing an example of an energized activated carbon regeneration device, Figure 2 is a cross-sectional view of the regeneration furnace used in the example, and Figure 3 is the weight of the weight, the maximum resistance value in the regeneration process, and the maximum applied voltage. FIG. 1...graphite electrode, 2...power supply, 3...
... Regeneration tank, 4 ... Gravel layer, 5 ...
- Waste activated carbon, 6... Channel, 7... Steam generation section, 8... Heat source, 9... Temperature detector, 10... ...Weight, 11...Vent.

Claims (1)

[Scope of Claims] 1. In a method consisting of a drying process, a desorption process, and an activation process in which an electric current is passed through used waste activated carbon that has adsorbed organic matter to generate Joule heat and the waste activated carbon is heated and regenerated, pressure is applied to the activated carbon layer while the current is being applied. A method for regenerating activated carbon, characterized in that the treatment is carried out by reducing the current carrying resistance of the activated carbon and lowering the voltage applied to the regeneration furnace. 2. The method for regenerating activated carbon according to claim 1, wherein the activated carbon bed is pressurized from above in a regeneration furnace tank, and is treated by applying a pressure of 0.05 kg/crli or more. 3. The activated carbon regeneration method according to claim 1 or 2, wherein the water vapor supplied in the activation step is treated by mixing a water gas reaction gas.