JPH067902B2 - Solvent recovery device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a solvent recovery apparatus, and more particularly to a solvent recovery apparatus which has a high efficiency of recovering an organic solvent in various fluids to be processed and which can be reduced in size and weight. .

[Prior Art] Since exhaust gas containing various organic solvents is generated in the manufacturing process of various industries such as printing industry, rubber industry, and petroleum industry, the organic solvent in the exhaust gas should be separated and recovered. Is required.

Conventionally, in order to recover an organic solvent, generally, a gas to be treated is fed to a packed column filled with activated carbon or activated carbon fiber (hereinafter referred to as “ACF”) as an adsorbent to adsorb the contained organic solvent. After separation, a method of desorbing and collecting the organic solvent adsorbed on the adsorbent is adopted. The conventionally provided ACF is based on pitch-based, polyacrylonitrile-based, or phenol-based long fibers, and is manufactured by carbonizing and activating the fibers.

[Problems to be Solved by the Invention] In a conventional packed tower filled with activated carbon or ACF as an adsorbent, high temperature regeneration cannot be performed, and degassing becomes insufficient, resulting in a short adsorbent life. However, there is a drawback that the recovery efficiency per unit adsorbent is low. Further, in the conventional recovery device, no consideration is given to the case where several kinds of organic solvents are mixed in the gas to be treated, and in this case, the recovered solvent is reused because it is recovered as a mixed solvent. There was a problem that it could not be done.

Further, in various processing apparatuses, there is always a demand for smaller size and lighter weight for the purpose of space saving, labor saving, etc., and further reduction in size and weight of the solvent recovery apparatus is also demanded.

The present invention solves the above-mentioned conventional problems, has a high recovery efficiency of an organic solvent, enables separation and recovery of a mixed solvent, and is small in size.
It is an object of the present invention to provide a solvent recovery device that can be reduced in weight.

[Means for Solving the Problems] The solvent recovery apparatus of the present invention comprises an adsorption separation means for adsorbing and separating an organic solvent from a fluid to be treated, and a heating means for desorbing the organic solvent adsorbed by the adsorbent, A solvent recovery device comprising a distillation column for fractionating the desorbed organic solvent, wherein the adsorbent is an activated carbon fiber obtained by activating a vapor grown carbon fiber. To do.

[Operation] Vapor grown carbon fiber (hereinafter referred to as “VGCF”) is produced in the gas phase by a thermal decomposition reaction of hydrocarbon gas with a catalyst as a nucleus. VGCF usually has a diameter of 0.005
˜5 μm, aspect ratio 10 or more, preferably 100˜
The carbonaceous whisker is 1000, has a bulk density of 0.01 to 0.2 g / cm ³ , and has a carbon content of 99% by weight and is fine, has a small bulk density, and is lightweight.

Due to its production mechanism, VGCF has heat resistance, high carbon purity, can be regenerated at high temperature, and has no problem of acid production due to steel treatment.

The ACF used in the present invention is obtained by activating a VGCF having such excellent properties as a raw material and activating the VGCF, and since it inherits the excellent properties of the raw VGCF, it has excellent heat resistance and Shows a bulk morphology in which whiskers that are lightweight and have a low bulk density are entangled.

Therefore, because of its excellent heat resistance, high-temperature regeneration by steam or electric heater heating is possible, so that desorption or degassing of the organic solvent adsorbed and recovered can be efficiently and sufficiently performed. Therefore, the life of the adsorbent can be extended by a factor of 2 to 3 compared to the conventional case.

Further, since the ACF according to the present invention has a bulk shape in which whiskers having a light weight and a low bulk density are entangled with each other, it is not necessary to consider the strength of the packed tower structure, compaction packing is possible, and the packing volume per unit weight is conventionally. Can be significantly reduced to about 1/2. Therefore, not only the weight of the device but also the size can be reduced. Furthermore, since there is almost no pressure loss to the fluid to be treated, highly efficient treatment is possible.

Since the solvent recovery apparatus of the present invention also comprises a distillation column for fractionating the desorbed organic solvent, it effectively deals with the fluid to be treated containing several kinds of organic solvents, It can be efficiently separated and collected.

[Examples] Examples of the solvent recovery apparatus of the present invention will be described below with reference to the drawings.

FIG. 1 is a system diagram showing an embodiment of the solvent recovery apparatus of the present invention.

In the solvent recovery apparatus of the present embodiment, two packed columns 1 and 2 filled with ACF obtained by activating VGCF are provided in parallel as adsorption separation means for adsorbing and separating the organic solvent from the fluid to be treated. ing. Then, a condenser 3 for separating the organic solvent-containing liquid recovered in the packed towers 1 and 2 into oil / water, an oil / water separation tank 4, and a heat exchanger 5 for distilling and separating the organic solvent separated in the oil / water separation tank 4, It is mainly composed of a distillation column 6 and a condenser 7.

The packed towers 1 and 2 are provided with steam hoods 8 and 9 on their outer surfaces for heating and regeneration by steam, respectively, so that steam can be supplied to the packed beds 1A and 2A in the towers to be regenerated by heating. It is configured. 1 in the figure
1 to 30 are pipes, D _{1 to} D ₄ are dampers, B is a blower, V
_{1 to} V ₃ represent valves.

In order to recover an organic solvent from a fluid to be treated such as an exhaust gas containing an organic solvent by such a solvent recovery device, first, the valves V _{1 to} V ₃ are closed, the dampers D ₁ and D ₃ are opened, and the damper D is opened.
₂ and D ₄ are closed, blower B is operated, and pipe 1
The fluid to be treated is supplied to the first packed tower 1 via 1, 12 and 13, and the organic solvent is adsorbed and separated by the ACF of the packed bed 1A. The fluid after the organic solvent has been separated and removed is the piping 14, 1
It is discharged from the system after passing 5. When the organic solvent is adsorbed and separated in the packed tower 1 and the adsorbability of the packed tower is lowered, the damper D ₁ is closed, the dampers D ₂ and D ₄ are opened, and the fluid to be treated is passed through the pipes 12 and 16 to the second position. Is supplied to the packed tower 2 for processing (the processing fluid is similarly discharged from the pipes 17 and 15), and the valves V ₁ and V ₂ are opened to open the pipe 18,
19 through the steam hood 8 of the packed tower 1 to the packed bed 1A
Steam is supplied to the ACF to heat and regenerate the ACF of the packed bed 1A. The organic solvent or the like adsorbed on the ACF is desorbed by the heat regeneration, and the desorbed substance is the pipe 20 (including the organic solvent and water),
It is supplied to the condenser 3 via 21 and the agglomerates are piped 2
It is introduced into the oil / water separation tank 4 via 2. The water layer separated in the oil / water separation tank 4 is discharged from the system through the pipe 23. On the other hand, the oil layer is introduced into the distillation column 6 through the pipe 24 and the heat exchanger 5, and the low boiling solvent A is discharged through the pipe 25. The low boiling solvent A is condensed in the condenser 7 and discharged from the system through the pipe 26 to be collected. In addition, a part is circulated through the pipe 27 to the distillation column. High boiling solvent B remaining in the distillation column 6
Is extracted from the pipe 27, heat-exchanged in the heat exchanger 5, and recovered.

When the regeneration treatment of the packed tower 1 is completed and the adsorption capacity of the packed bed 2A of the packed tower 2 is reduced by the treatment in the packed tower 2, the damper D ₁ is opened and D ₂ is closed, and the valve V is closed.
₃ is opened and the valve V ₂ is closed to perform adsorption / separation in the packed tower 1, while regenerating the packed tower 2. The organic solvent and the like desorbed by the regeneration treatment with steam supplied to the packed tower via the pipes 18 and 29 are supplied to the condenser 3 via the pipes 30 and 21 and separated and recovered in the same manner as above.

In this way, by arranging two packed columns in parallel and performing adsorption and regeneration alternately, continuous treatment of the fluid to be treated becomes possible.

The apparatus shown in FIG. 1 is an embodiment of the solvent recovery apparatus of the present invention, and the present invention is not limited to the illustrated apparatus as long as the gist thereof is not exceeded.

For example, the packed tower packed with the ACF adsorbent may be one tower instead of two towers, but two or three or more towers are provided and each tower is sequentially used for solvent recovery and regeneration treatment. By alternately carrying out, continuous operation becomes possible, which is extremely advantageous.

By disposing two or more distillation columns in multiple stages, it is possible to separate and recover three or more kinds of solvents.

Further, the regeneration of the packed tower can be performed by steam heating as shown in FIG. 1 or electric heater heating.

A used as an adsorbent in the solvent recovery apparatus of the present invention
CF is VGCF, for example, CO ₂ , water vapor, air,
1 at 600-1200 ℃ in oxidizing atmosphere such as combustion gas
It is obtained by activation treatment for 0 to 120 minutes. Such ACF regeneration conditions are not particularly limited and are usually 150 to 250 ° C., but the ACF used in the present invention can sufficiently withstand high temperature heating regeneration up to 400 ° C.

The solvent recovery device of the present invention using such an ACF adsorbent, from the exhaust gas discharged from various industrial fields such as printing industry, rubber industry, tape industry, synthetic resin industry, oil and fat industry, cleaning industry, cellophane industry, etc., It is extremely effective in recovering organic solvents such as alcohols, ketones, esters, ethers, paraffin hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, nitrogen-containing compounds and sulfur compounds.

Specific examples of the organic solvent suitable for recovery by the solvent recovery device of the present invention are as follows.

Petroleum hydrocarbons: benzene, toluene, n-hexane, naphtha, rubber volatile oil, cyclohexane, thinner, etc.Halogenated hydrocarbons: trichloroethylene, tetrachloroethylene, 1,1,1-trichloroloethane, methylene chloride, trichlorobenzene, chloroform , Carbon tetrachloride, Freon, etc. Ketones: acetone, MBK (methyl isobutyl ketone), cyclohexanone, etc. Esters: ethyl acetate, butyl acetate, methyl cyclohexyl acetate, etc. Ethers: ethyl ether, dioxane, THF (tetrahydrofuran), furfural, methyl Cellosolve, etc. Alcohols: Methanol, ethanol, isopropyl alcohol, butanol, etc. Polymerization monomers: Vinyl chloride, vinyl acetate, acrylic acid, acrylic ester, Styrene, etc. The present invention is particularly effective in the solvent separated and recovered from the exhaust gas containing two or more of these organic solvents.

[Effects of the Invention] As described in detail above, according to the solvent recovery apparatus of the present invention, V
Since ACF obtained by activating GCF is used as the adsorbent, the adsorbent can be regenerated at high temperature, and the adsorbent can be easily and efficiently regenerated.

As a result, the life of the adsorbent is greatly extended.

Highly efficient processing is possible with almost no pressure loss to the fluid to be processed.

The weight of the device can be reduced by the lightweight ACF.

The ACF having a small peak density enables high-pressure dense packing, and the packing volume can be reduced, so that the apparatus can be made compact.

In addition to the effects described above, since the distillation column is provided, each organic solvent can be efficiently separated and recovered from the fluid to be treated containing two or more kinds of organic solvents.

Such an excellent effect is exhibited, and its industrial utility is extremely high.

[Brief description of drawings]

FIG. 1 is a system diagram showing an embodiment of the solvent recovery apparatus of the present invention. 1, 2 ... Packing tower, 3, 7 ... Condenser 4 ... Oil-water separation tank, 5 ... Heat exchanger, 6 ... Distillation tower.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C01B 31/10 D01F 9/127 7199-3B

Claims (1)

[Claims] 1. An adsorption separation means for adsorbing and separating an organic solvent from a fluid to be treated, a heating means for desorbing the organic solvent adsorbed on the adsorbent, and a distillation for fractionating the desorbed organic solvent. A solvent recovery apparatus comprising: a tower, wherein the adsorbent is activated carbon fiber obtained by activating vapor grown carbon fiber.