JPS59162114A - Regeneration of active carbon - Google Patents

Abstract

PURPOSE:To regenerate active carbon in such a way that it has adsorption ability like unused active carbon, by heat-treating active carbon having reduced adsorption ability, washing it with a dilute aqueous solution of hydrochloric acid. CONSTITUTION:Hydrochloric acid 1 is blended with water in the preparation tank 3 with stirring to make a dilute aqueous solution of hydrochloric acid having a given concentration. Active carbon having reduced adsorption ability is heat- treated, and fed to the treating tank 5. The dilute aqueous solution is added to the tank 5, the active carbon is blended with the dilute aqueous solution of hydrochloric acid with stirring, washed, allowed to stand, reblended with stirring, and the waste dilute aqueous solution of hydrochloric acid is taken out from the central outlet 6. This washing operation is repeated plural times, and finally total amount of the waste aqueous solution of hydrochloric acid is taken out from the bottom outlet 7. Finally, water is fed from the pipe 8 to the tank if necessary, and water is taken out from the top outlet 9 while washing hydrochloric acid in the active carbon with it. The active carbon after treatment is packed into the column 12 for active carbon treatment by N2 10 and it is reused. The waste aqueous solution of hydrochloric acid is neutralized with NaOH and discharged.

Description

[Detailed description of the invention] The present invention relates to a method for regenerating activated carbon.

It is widely practiced to regenerate activated carbon whose adsorption capacity has been reduced by heating, and activated carbon used for purifying substances such as water, sugar, and adipic acid can be reused simply by this heating regeneration. However, even if the activated carbon used in the purification of highly viscous substances such as nylon salts is reused by heating only, only the color tone of the purified substance can be improved, but other qualities will hardly be affected. However, due to insufficient regeneration, it was not possible to restore the adsorption capacity to the level of unused coal. 7.Therefore, heat regeneration alone is sufficient (this is a method for regenerating used activated carbon that could not be regenerated).As a result of extensive investigation, we found that the recycled coal after heat treatment had a large amount of ash attached to it, and that this ash content could be purified. However, this ash adhesion can be removed by treatment with dilute hydrochloric acid under specific conditions (this results in an adsorption capacity equal to or greater than that of unused charcoal). I discovered this and made the present invention.

The purpose of the present invention is to rub activated carbon whose adsorption capacity has decreased so that it can be used repeatedly by returning it to an adsorption capacity comparable to virgin carbon. An object of the present invention is to provide an effective regeneration method for regenerating activated carbon using purified carbon.

The above object can be achieved by heat-treating the activated carbon whose adsorption capacity has been reduced, then repeatedly washing the activated carbon with stirring in a dilute aqueous hydrochloric acid solution several times, and then washing with water if necessary.

The heat treatment in the method of the present invention may be a heat regeneration treatment that is normally carried out for regeneration of activated carbon.

For example, external heating at 800-2000'Ct,
and direct heat heating? There is a lot of regeneration.

The method for stirring and cleaning in a dilute aqueous hydrochloric acid solution is to add a dilute aqueous solution of hydrochloric acid to activated carbon, stir, and then remove most of the dilute aqueous solution; Another method is to let it stand still, stir it again, and then remove most of the dilute hydrochloric acid water bath solution.

The above (6) agitation cleaning must be repeated multiple times, that is, twice or more, for electrical equipment, and the number of repetitions depends on the amount of dilute hydrochloric acid aqueous solution to activated carbon.In other words, the larger the amount of dilute hydrochloric acid aqueous solution, the less However, if the IM of the dilute hydrochloric acid aqueous solution is small, it is necessary to increase it.For example, the amount of dilute hydrochloric acid aqueous solution (
4 to 8 per wash) if it is twice the activated carbon capacity.
It is preferable to repeat this process several times, and the total amount of the dilute hydrochloric acid aqueous solution used is preferably about 5 to 10 times the activated carbon capacity1.
If the amount of dilute hydrochloric acid aqueous solution used is small, it is difficult to remove the ash content from the activated carbon sufficiently.

The amount of the dilute aqueous hydrochloric acid solution used here is preferably at least twice the volume of activated carbon for one wash.

If the amount of this diluted hydrochloric acid aqueous solution is too small, contact between the activated carbon and the diluted hydrochloric acid aqueous solution will be insufficient even with stirring, making it difficult to regenerate sufficiently. In addition, the concentration of dilute hydrochloric acid aqueous solution is 1 to 6
The weight is preferably about φ.

The order of the above heat treatment and dilute hydrochloric acid treatment is that the heat treatment is always carried out first, and the dilute hydrochloric acid treatment is carried out later. Even if heat treatment is performed after the treatment, the effect of the dilute hydrochloric acid treatment cannot be obtained.

In cases where the equipment used for the preparation is not acid resistant, or where the substance to be purified must not be contaminated with hydrochloric acid, it is desirable to perform water washing after treatment with diluted hydrochloric acid.

The process of carrying out the dilute hydrochloric acid treatment described above will be explained with reference to FIG. A dilute aqueous hydrochloric acid solution with a predetermined concentration is prepared by stirring and mixing.The activated carbon whose adsorption capacity has been reduced is subjected to heat treatment, and the specified amount is poured into the processing tank 5.The adjusted dilute hydrochloric acid aqueous solution is poured into the processing tank 5 from the pipe 4f. Activated carbon, a dilute hydrochloric acid aqueous solution, and water are supplied from piping 8 as needed, and the hydrochloric acid in the activated carbon is taken out from the upper outlet 9 while being washed.It is neutralized with an alkali as in the treatment and discarded.

The active layer regeneration method of the present invention involves the regeneration of activated carbon using nylon salts (e.g. hexanotylene diammonium acetate), purification of high viscosity substances, The activated carbon regenerated by the method of the present invention has both color and quality.
Purification of substances that also requires improvement of +Q, 4! f3 can be used.

Next, the present invention will be further explained from (111f).

In the following examples, the quality of the AH salt is 95°C x 2
It was expressed by the color tone (APHA) after heating under hr conditions and the ultraviolet transmittance (UVT) after the same heating.

Color tone (APHA)...AH saltiness 4 Q wt
Pour 100ml of the aqueous solution into three colorimetric tubes, and
APHA value was determined by color comparison with HA standard solution.

Ultraviolet transmission* (UVT)...AH salt concentration 4D
The ratio of the value measured with a 280 mμ ultraviolet transmittance meter of an aqueous solution made of wt to the same ultraviolet transmittance value e of distilled water is expressed as a ratio.

Example 1 HegizamethiV diammonium adipate (Heto■
The granular activated carbon whose adsorption capacity had decreased was regenerated by the following method.

After external heating at 850℃ for 2 hours, a113 heavy 1R
A related dilute aqueous hydrochloric acid solution was added in an amount twice the amount of activated carbon, stirred for 1 minute, allowed to stand for 1 hour, and then stirred again for 1 minute. After the activated carbon had settled, the upper layer of the contaminated dilute hydrochloric acid water Met was discarded in an amount equivalent to one time the amount of activated carbon. Next, a new diluted hydrochloric acid aqueous solution was added to replenish the discarded amount, and as in the previous time, stirring - standing, stirring, standing, and disposal of diluted hydrochloric acid were carried out (second time).

This was repeated a total of 5 times, and the entire amount of the dilute hydrochloric acid aqueous solution was discarded at the end.The final standing was carried out for 12 hours or more.

Thereafter, it was washed with water to remove hydrochloric acid.

Using the regenerated charcoal (c) obtained by the above-mentioned method and the unused charcoal which had not been used in purified E, AH salt was purified in the following manner.

28.5 A cylindrical glass activated carbon column with a diameter of 380 mm and a diameter of 380 mm was filled with 185 mm of granular activated carbon, and a crude A H salt solution/I! (Fuchi) g-so weight %) was purified by passing the solution through a trowel at a flow rate of 6f. The liquid flow rate is 1 kg of activated carbon.
This is the value shown in (:, g/hr).

The adsorption capacity of the regenerated activated carbon was evaluated by measuring the color tone (APHA) and ultraviolet transmittance (UVT) of the purified A and H salts obtained. 2r of the results! 1st table and 2nd table
Figure (shown here)

t, c o, rough A HJi U) A P H/' HaJ 01 (JVT was 81.

Table 1 Regenerated coal (A) 1, which was regenerated by the method of the present invention, showed a slightly different adsorption capacity than unused coal.

Example 2 In fact, AH salt was purified using the regenerated coal (A) obtained in 16 Example 1, and the regenerated coals (B) and (C) regenerated by the following method.

The same granular activated carbon with reduced adsorption capacity as that regenerated in Example 1 was regenerated only by external heat treatment at 850'C for 12 hours to obtain regenerated carbon (B).

Regeneration was carried out under the same conditions as in Example 1, except that the order of heat treatment and dilute hydrochloric acid treatment was reversed to obtain regenerated coal (C).

A H salt cl) 1% J W Ha, 500maiX 4
63'OmmH (1) A cylindrical stainless steel activated carbon column was packed with granular activated carbon 540β, and crude AI (salt aqueous solution (
The liquid was passed through a trowel with a flow rate of 5e.

The color tone (APHA) and ultraviolet transmittance (UVT) of the purified AI salt obtained are shown in Table 2 and Figure 3.

In addition, crude AI salt A P HA is 30. UVT is 13
It was Q.

Table 2: There was no difference in color tone of purified AH salts, but ultraviolet transmittance t
There were significant differences. In other words, the regenerated coal (A) treated with heating and dilute hydrochloric acid was as good as unused coal, but the regenerated coal treated with only heat treatment (13) and the regenerated coal that was pressed with dilute hydrochloric acid and heat treatment were as good as virgin coal. In the case of (C), the ultraviolet transmittance was extremely poor.

Example 6 After changing the number of times of dilute hydrochloric acid treatment in Example 13, activated carbon was regenerated under the same conditions as in Example 1, and the regenerated carbon (L) and (g) were used.

Number of times of dilute hydrochloric acid treatment of recycled coal (A) ゛ 5 times Regenerated coal (1)
), : 3 times r + j raw charcoal (i
r, ): Purification and purification of AH salt was performed once in the same manner as in Example 1 using each recycled coal, and the results of measuring the ultraviolet absorption rate of the purified AH salt obtained in 1) are shown in Figure 2. I showed this.

Regenerated coal that has been treated with acid only once (+!0 indicates that the adsorption capacity has not been fully recovered)33

[Brief explanation of drawings]

FIG. 1 is a process diagram showing an embodiment of dilute hydrochloric acid treatment carried out by the method of the present invention. 3: Adjustment tank for hydrochloric acid aqueous solution Also, Figures 2, 3 and 3 are graphs showing the adsorption capacity of activated carbon based on the quality e after activated carbon treatment. Regenerated coal (A), (D): Regenerated coal according to the present invention
B), (C), (g)) Methods other than the inventiveness? − Recycled coal patent applicant Toshi Co., Ltd. 〇 −−

Claims (1)

[Claims] A method for regenerating activated carbon, which comprises heat-treating activated carbon whose adsorption capacity has been reduced, and then repeatedly washing the activated carbon with stirring in a dilute aqueous hydrochloric acid solution several times.