JP2008237988A - Regeneration method of organic solvent - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a regeneration method of a recovered organic solvent capable of regenerating the recovered solvent in an extremely high level by effectively removing the acid component in the recovered solvent using an adsorbing material even in a case that the acid component is contained in the recovered solvent recovered by adsorption. <P>SOLUTION: The regeneration method of the recovered solvent is characterized by removing the acid component from the acid component-containing recovered solvent, which is recovered from an organic solvent recovery equipment using the adsorbing material. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for regenerating an organic solvent.

  In recent years, from the viewpoints of industrial waste reduction, global warming prevention, and air pollution prevention, organic solvent-containing gas generated from the process is absorbed and recovered by the organic solvent recovery device in the process using organic solvent to reduce environmental impact. Therefore, it is desired to recycle and reuse the recovered organic solvent.

  As a method for recovering and reusing the organic solvent, conventionally, two or more adsorption tanks filled with activated carbon fibers are provided as an adsorbent, and the organic solvent contained in each adsorption tank. A means for supplying a processing gas and a desorption means for ejecting water vapor are provided, and the adsorption operation and the desorption operation are alternately switched. The organic solvent in the adsorbed gas to be treated is desorbed and desorbed. A method of recovering and reusing a solvent by condensing and separating water and water vapor is employed.

  In such a configuration, since the adsorbent is a fiber made of activated carbon fiber, the outer surface area is large, and pores effective for the adsorption and desorption of organic solvent gas can be arranged on the fiber surface, so that the decomposition of the solvent The desorption operation that affects the properties can be performed at a low temperature and in a short time, the decomposability of the recovered solvent is very low, and the recovered solvent can be reused continuously and stably.

  However, in the conventional organic solvent gas adsorption and recovery solvent recycling method, when the gas to be treated contains a small amount of impurities such as acid components (for example, NOx, SOx, etc.), or the organic solvent to be recovered and reused In the case of hydrolysis, the recovered solvent recovered from the organic solvent recovery equipment contains an acid component. Considering the corrosion of the solvent use line and the effect of the product on the product due to the acid content, the recovered solvent must be recycled. I couldn't use it.

  Therefore, when an acidic substance is contained in the recovered solvent that has been adsorbed and recovered, a method of performing distillation purification is used as a method of regenerating the recovered solvent. It has been found that the components cannot be completely removed and are contained in the recovered solvent. Therefore, neutralizing the acid component contained in the recovery solvent by adding a neutralizing agent such as a basic substance to the recovery solvent, and then removing the acid component in the recovery solvent by distillation purification. It is possible. However, in the neutralization treatment of the recovered solvent, the pH of the recovered solvent is measured before and after the neutralization treatment, the addition amount of the basic substance necessary for the neutralization treatment is made appropriate, and the pH of the recovered solvent is adjusted to 6-8. This is necessary, and the recovered solvent cannot be regenerated and reused continuously and stably. Therefore, there is still no method for recovering the recovered solvent that can meet market demands.

JP 2001-347126 A

  The present invention has been made against the background of the problems of the prior art, and even when an acid component is contained in the recovered solvent that has been adsorbed and recovered, the adsorbent is used to effectively recover the acid in the recovered solvent. It is an object of the present invention to provide a method for regenerating a recovered solvent that can regenerate the recovered solvent at an extremely high level by removing components.

The present invention is as follows.
1. A method for regenerating a recovered solvent, comprising removing an acidic component contained using an adsorbent from a recovered solvent containing an acid component recovered from an organic solvent recovery facility.

2. 2. The method for regenerating an organic solvent as described in 1 above, wherein the recovered solvent is passed through a packed bed of an adsorbent having an average particle diameter of 0.5 mm or more.

3. 3. The method for regenerating a recovered solvent according to 1 or 2 above, wherein the adsorbent contains any one of activated carbon, activated alumina, zeolite, titania, zirconia, magnesia and anion exchange resin.

4). 4. The method for regenerating a recovered solvent according to any one of 1 to 3, wherein alkali metal sodium and / or potassium is vapor-deposited or supported on the adsorbent.

  In the present invention, even when an acid component is contained in the recovered solvent recovered by adsorption, the acid component in the recovered solvent is effectively passed by passing the recovered solvent through a filling tank using the adsorbent. This makes it possible to regenerate the recovered solvent at an extremely high level.

  According to the method for regenerating a recovered solvent of the present invention, a method for recovering a recovered solvent that recovers a gas containing a solvent and reuses the solvent, and the solvent is not particularly limited. , Trichloroethane, trichloroethylene, tetrachloroethylene, ethyl acetate, methyl ethyl ketone, acetone, phenol, cyclohexanone, and the like.

  By recovering the gas containing these solvents and bringing the recovered solvent into contact with the adsorbent, the acid content in the recovered solvent is adsorbed by the adsorbent, so that the acid component can be removed with a sufficiently high removal rate. Can do. In addition, the adsorption reaction is mainly an ion exchange between the surface hydroxyl group of the adsorbent active site and the acid component, and OH- is released with the adsorption of the acid component, so there is no generation of salt as in the neutralization reaction, Only the acid content can be removed from the recovered solvent.

  Examples of the adsorbent include activated carbon, activated alumina, zeolite, titania, zirconia, magnesia, anion exchange resin and the like, including any of them, and may be used alone or in combination of two or more. Good. Moreover, you may vapor-deposit or carry | support alkali metals, such as sodium and potassium, to an adsorbent.

  Among the above adsorbents, activated alumina, zeolite, and anion exchange resin are preferable, and activated alumina has many active sites effective for ion exchange on the adsorbent surface and inside the pores, and contains acid components and / or harmful ions. It is particularly preferable since it has excellent removal performance and is inexpensive.

  In addition, the method for bringing the recovered solvent into contact with the adsorbent is not particularly limited as long as both can be sufficiently contacted, but as a preferred embodiment in terms of the removal rate of acidic components in the recovered solvent, maintenance management, and running cost, The method shown in can be mentioned.

  That is, 1st Embodiment concerning this invention passes the collection | recovery solvent containing an acid component through the packed bed of the granulated material which is an adsorbent and whose average particle diameter is 0.5 mm or more. As a result, when the recovered solvent passes through the packed bed, the recovered solvent and the solid base can be sufficiently brought into contact with each other. Therefore, the acid component removal rate is increased by absorption of the acid component in the gas into the adsorbent. It can be achieved at a standard level.

  More specifically, for example, the granulated product is filled in a predetermined container, and a recovery solvent supply facility containing an acidic component is connected to the preceding stage, and a particle removal filter is connected to the subsequent stage via pipes. And the acid component in a collection | recovery solvent can be removed by introduce | transducing the collection | recovery solvent containing an acidic component in a container, and letting it pass through the packed bed of a granulated material.

  Moreover, the average particle diameter of the said granulated material is 0.5 mm or more as above-mentioned, Preferably it is 0.5-6 mm. In addition, if the average particle diameter of the granulated product is less than 0.5 mm, the pressure loss of the packed bed increases, or further, the particle removal filter that is pulverized during filling or processing and accumulates in the pipe. Phenomena such as clogging are likely to occur. In general, when the average particle diameter exceeds 6 mm, the contact efficiency between the recovered solvent and the granulated product is lowered, and the acid component removal rate tends to be insufficient.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example, this invention is not limited to a following example at all.

[Example 1]
(Solvent recovery)
Examples are shown below with the organic solvent treatment apparatus shown in FIG. 1 as a basic flow. A gas to be treated A containing 1000 ppm of ethyl acetate and 0.5 ppm of NO ₂ was introduced into the solvent recovery device 2 with a blower 1 at an air flow rate of 20 Nm ³ / min, and was covered by an activated carbon fiber filter 4 provided inside the adsorption tank 3. The treatment gas was adsorbed. The treated gas after the adsorption treatment was discharged out of the system as clean air. Further, ethyl acetate and NO ₂ in the adsorbed gas to be treated were desorbed by the water vapor 5 and condensed by the condenser 6 to obtain a recovered solvent C.

  The pH and nitrate ion concentration were measured as acidic content in the recovered solvent. The pH was measured using a pH meter (manufactured by Horiba Seisakusho), an electrode for a non-aqueous solvent was used for the electrode, and the ion concentration was measured by ion chromatography (manufactured by DIONEX) to measure the nitrate ion concentration in the regeneration solvent. The pH in the recovered solvent was 3.8, and the nitrate ion concentration was 2.3 ppm.

(Removal of acid component using packed bed)
Next, an acid component removal test was performed according to the following procedure. In this test, a solvent having a pH of 3.8 and a nitrate ion concentration of 2.3 ppm was used.

  First, 34 g of the above adsorbent 8 granulated product was filled in a stainless steel filling container 7 having an inner diameter of 250 mm and a length of 1000 mm to form a packed bed. A metering pump 9 was connected to the front stage of the filled container, the recovered solvent was supplied to the adsorbent packed bed at a rate of 1 L / min, and the regenerated solvent D that passed through the adsorbent packed bed was collected in a glass container. The adsorbent granulated product was an activated alumina granular product (manufactured by Sumitomo Chemical Co., Ltd.), and a spherical product having a particle diameter of 1 to 2 mm was used.

  Next, the collected regeneration solvent was measured for pH and nitrate ion concentration as acidic components. The pH is measured using a pH meter (manufactured by Horiba, Ltd.), the electrode is a nonaqueous solvent electrode, and the ion concentration is measured by ion chromatography (manufactured by DIONEX) to measure the nitrate ion concentration in the regenerating solvent. did. The pH in the regeneration solvent was 5.3, and the nitrate ion concentration was 0.1 ppm or less.

[Comparative Example 1]
On the other hand, the pH of the solvent collected through an empty filling container not filled with the granulated product was 3.8, and the nitrate ion concentration was 2.3 ppm. The measurement was performed by the method described in Example 1.

[Example 2]
Except that the adsorbent granulated product was an activated alumina granular product (manufactured by Sumitomo Chemical Co., Ltd.) and a spherical product having a particle diameter of 2 to 4 mm, the same condition evaluation as in Example 1 was performed. The pH was 5.2 and the nitrate ion concentration was 0.1 ppm or less.

[Example 3]
The same conditions as in Examples 1 and 2 except that the adsorbent granulated product was an anion exchange resin 550-OH (manufactured by Dow Chemical Company), a spherical product with a particle diameter of 0.6 mm, and the adsorbent weight was 3 kg. Evaluation was performed. As a result of measuring the acidic content in the regenerating solvent, the pH was 5.9 and the nitrate ion concentration was 0.6 ppm.

In the above examples, ethyl acetate as a solvent and NO ₂ as an acidic component were recovered, and the recovery method of the recovered solvent using adsorbent activated alumina or anion exchange resin was described. The adsorbent used for the regeneration is not limited to the previous range.

  In the present invention, even when an acid component is contained in the recovered solvent recovered by adsorption, the acid component in the recovered solvent is effectively passed by passing the recovered solvent through a filling tank using the adsorbent. It is possible to provide a regeneration method that makes it possible to regenerate the recovered solvent at an extremely high level.

It is a basic processing flow figure of an organic solvent recovery system.

Explanation of symbols

A: Gas to be treated B: Clean gas C: Recovery solvent D: Recycled solvent 1: Blower 2: Solvent recovery device 3: Adsorption tank 4: Activated carbon fiber filter 5: Water vapor 6: Condenser
7: Filling container 8: Adsorbent 9: Metering pump

Claims (4)

  A method for regenerating a recovered solvent, comprising removing an acidic component contained using an adsorbent from a recovered solvent containing an acid component recovered from an organic solvent recovery facility.   The method for regenerating an organic solvent according to claim 1, wherein the recovered solvent is passed through a packed bed of an adsorbent having an average particle diameter of 0.5 mm or more.   The method for regenerating a recovered solvent according to claim 1 or 2, wherein the adsorbent contains activated carbon, activated alumina, zeolite, titania, zirconia, magnesia, or an anion exchange resin. 4. The method for regenerating a recovered solvent according to claim 1, wherein alkali metal sodium and / or potassium is vapor-deposited or supported on the adsorbent.

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