JPH09124522A - Cleaning and reclamation of alcohol solution used for washing or purification of polysaccharide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To purify and reclaim a used alcohol solution without changing the original composition of the solution to enable the reuse of the solution and decrease the amount of industrial waste by passing an alcohol solution used in the washing or purification of polysaccharides through a separation membrane. SOLUTION: An alcohol solution used for the washing or purification of a polysaccharide is passed through a separation membrane to separate and remove impurities and unnecessary components intruded into the alcohol solution. The alcohol solution is preferably an ethanol solution having a water content of 40-90wt.%. The separation membrane is preferably a solute-separation membrane of a loose reverse osmosis membrane level resistant to ethanol and effective for inhibiting the permeation of a substance having a molecular weight of 200-4,000 in an alcohol solution. The material of the membrane is preferably polyimide, polyamide, etc. The water mixed into the alcohol solution is preferably removed by the dehydration treatment by a permeation evaporation method using a permeation evaporation membrane having selective water-permeability. The permeation evaporation membrane is e.g. polyvinyl alcohol membrane.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to the treatment of an alcohol solution used for washing or purifying polysaccharides in the food industry, chemical industry, etc., and particularly to washing or purifying polysaccharides such as mannan for konjac production. The present invention relates to a method for purifying and regenerating the used alcohol solution using a separation membrane.

[0002]

2. Description of the Prior Art In order to produce a high-value-added white high-grade konjac, the raw material polysaccharide mannan is thoroughly washed and purified to remove impurities such as organic acids and bolls. There is a need. Although most of these impurities are water-soluble substances, many polysaccharides such as mannan generally dissolve or become a semi-dissolved sol when soaked in water. You can't use water. For this reason, water-soluble organic solvents such as alcohol and acetone are used for washing and purifying polysaccharides such as mannan.

However, the above-mentioned organic solvent for washing or refining deteriorates in washing / extracting or purifying ability as various impurities contained in the crude polysaccharide elute, and becomes a waste solution due to aging. However, most of the waste solution is burned by industrial waste as industrial waste, and is not reused in the cleaning / refining process. This is an economical treatment and recycling of these waste solutions.
This is because there is no suitable way to reuse it.

[0004]

Therefore, according to the present invention, impurities and unnecessary components are separated and removed from a used alcohol solution in washing or refining a polysaccharide to basically change the original composition of the alcohol solution. The present invention provides a used alcohol solution purification / regeneration method in which the treated alcohol solution can be reused for washing / purification of polysaccharides, etc. without purification / regeneration.

[0005]

The present invention aims to separate and remove impurities and unnecessary components mixed in the alcohol solution by passing an alcohol solution used for washing or purifying polysaccharides through a separation membrane. Characterize.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a recycling system diagram of an alcohol solution used for purifying polysaccharides by a membrane separation method to which the present invention is applied. In the figure, mannan is purified with hydrous ethanol in the purification step to produce konjac. Sent to the process. The waste solution of hydrous ethanol from the refining process is sent to the conditioning tank. Traditionally, waste solutions were handed over to industrial waste providers.

In the present invention, the waste solution from the adjustment tank is filtered to remove solids, and the filtered waste solution is purified by separating impurities and unnecessary components by the loose reverse osmosis membrane. The purified permeate is recycled to the purification process.

In the above process, in order to purify and regenerate the alcohol solution used for washing or purifying mannan, a chemical change such as swelling or dissolution is caused in a lower alcohol such as methanol, ethanol or isopropanol. It is effective to apply a separation membrane having a separation performance even in an alcohol solution, using a non-use polyimide, polyamide, polyvinylidene fluoride, polyacrylonitrile, cellulose acetate, etc. as a membrane material. Also,
Molecular weight of 300 to 40,000 mixed in purification and purification processes
In order to effectively separate / remove about 0 substances, it is preferable to use a reverse osmosis level separation membrane having a blocking ability even for low molecular weight substances.

FIG. 2 is a graph showing the effect of ethanol concentration on the inhibition rate of PEG (polyethylene glycol). As is clear from the graph, existing separation membranes generally have poor separation performance due to the presence of a high concentration of alcohol. Although showing a tendency, it is preferable to use an ethanol solution containing water as a solution used for washing or purification of the polysaccharide in order to suppress the deterioration of the separation performance and maintain the rejection rate of the solute at an effective level. Further, in this case, the water content is in the range of 25 to 90 wt%, preferably 40 to 90 wt%.
It is effective to control it within the range of 90 wt%. However, the solute separation membrane used in the present invention is not limited to a separation membrane using the above-mentioned polymer as a membrane material, and a solute having a relatively low molecular weight having sufficient chemical durability to the alcohol solution. Any separation membrane may be used as long as it has an effective degree of separation performance. In the present invention, it is assumed that the purified and regenerated alcohol solution is reused in the purification step or the like, and therefore it is desired that the alcohol concentration of the alcohol solution does not substantially change during the membrane separation process.

Therefore, as the solute separation membrane used in the present invention, a high performance reverse osmosis membrane capable of separating water and alcohol is not preferable, and a relatively loose reverse osmosis membrane having a molecular weight cutoff of at least 100 is preferable. . However, the molecular weight of 300-4 mixed in the purification / purification process of polysaccharides
Ordinary ultrafiltration membranes are not preferable for effectively separating and removing substances of about 20,000, and prevent at least the main component of relatively low-molecular substances having a molecular weight of 4,000 or less. It is necessary to be a solute separation membrane at the level of a loose loose osmosis membrane (also called a low pressure reverse osmosis membrane) that is capable. In addition, when washing or purifying polysaccharides with water attached or adsorbed on the surface or inside, the water is brought into the used alcohol solution and the water content of the waste solution also increases. In order to achieve
Need to be removed. Therefore, it is effective to use the pervaporation method using a pervaporative membrane having selective water permeability.

The pervaporation method, which is also called a vaporization method, heats the solution to be treated on the primary side, and depressurizes the secondary side (permeation side) through a separation membrane to keep it in the gas phase.
It is a membrane separation method in which a membrane permeation component such as water evaporated on the secondary surface of the membrane is condensed by a cold trap to be recovered. As the separation membrane, a polyvinyl alcohol-based membrane is most often used, but a membrane in which chitosan is chemically treated and a polyion complex-based membrane are also available.

In the present invention, any of these pervaporation membranes can be used, but the invention is not particularly limited to these membranes and has sufficient chemical durability against the alcohol solution. Membranes of any material can be used as long as they are permeation vaporization membranes showing selective permeability to water, and either flat plate type modules or hollow fiber type modules can be used.

The pervaporation treatment of the alcohol solution using these permeation vaporization membranes exhibiting selective permeation of water is carried out by separating and removing excess water attached to or adsorbed on the polysaccharide and brought into the system. Not only is it effective for re-adjusting the water concentration (or alcohol concentration) of the purified alcohol solution when the solute separation membrane used has some ability to block alcohol. Is.

[0014]

【Example】

Example 1 A solid solution was removed by filtering a waste solution obtained by purifying mannan for konjac with a filter paper using an aqueous ethanol solution adjusted to an ethanol concentration of about 15 wt%, and a commercially available polyamide loose reverse osmosis membrane was attached. When a membrane separation treatment was carried out at room temperature at a working pressure of 0.15 MPa using a batch type reverse osmosis apparatus, the rejection rate against dissolved unnecessary substances was 98% or more, and the membrane permeation flux of the water / ethanol mixed solution was about 0. It was 1 (t / m ² · d).

The ethanol concentration of this membrane permeate was the same as the ethanol concentration of the stock solution.

Example 2 Using the same method and conditions as in Example 1, about 25 wt%
When the waste solution obtained by purifying konjac mannan was purified using an aqueous ethanol solution adjusted to the above ethanol concentration, the rejection rate for dissolved unnecessary substances was about 98%.
The membrane permeation flux of the water / ethanol mixture is about 0. l (t
/ M ² · d). The ethanol concentration of this membrane permeate was the same as that of the stock solution, but this membrane had a molecular weight of 200 in an approximately 25 wt% ethanol aqueous solution.
It showed an inhibition rate of about 78% with respect to polyethylene glycol.

When konnyaku was actually produced from mannan purified using this regenerated ethanol solution, the qualities such as color tone, aroma and taste were found to be konjac produced from mannan purified using the first new ethanol solution. It didn't change.

Example 3 Using the same method and conditions as in Example 1, about 60 wt%
When the waste solution obtained by purifying konjac mannan using an ethanol solution adjusted to the above ethanol concentration was subjected to membrane separation treatment, the rejection rate for dissolved unnecessary substances was about 90%, and the membrane permeation flux of water / ethanol mixture Is about 0.1 (t
/ M ² · d) or less. The ethanol concentration of this membrane permeate was the same as the ethanol concentration of the stock solution.

Further, when konnyaku was actually produced from mannan purified using this regenerated ethanol solution, the quality such as color tone and taste was almost the same as konjac produced from mannan purified using a new ethanol solution of the same composition. It didn't change.

Example 4 Using the same method and conditions as in Example 1, about 25 wt%
When the waste solution obtained by purifying konjac mannan using a methanol solution adjusted to the above methanol concentration was subjected to membrane separation treatment, the rejection rate for dissolved unnecessary substances was about 98% or more, and the membrane permeation flux of water / methanol mixture was Is about 0.1 (t
/ M ² · d). The methanol concentration of this membrane permeate was the same as the stock solution.

Example 5 Almost in the same manner as in Example 1, a waste solution obtained by purifying konjac mannan using an ethanol solution adjusted to an ethanol concentration of about 25 wt% was treated with a cellulose acetate asymmetric reverse osmosis. When a batch type reverse osmosis device equipped with a membrane (having a separation performance of a loose reverse osmosis membrane) was used and subjected to a membrane separation treatment at an operating pressure of 0.15 MPa at room temperature, the rejection rate against dissolved unnecessary substances was about 86%. ,
The permeation flux of the water / ethanol mixture is about 0.2 (t / m
² · d). The ethanol concentration of this membrane permeate is
It was the same as the ethanol concentration of the stock solution.

Example 6 A solid solution was removed by filtering a waste solution obtained by purifying mannan for konjac with a filter paper using an aqueous ethanol solution adjusted to an ethanol concentration of about 25 wt%, and a polyimide system pervaporation membrane was attached. Using a batch type pervaporation apparatus, the degree of vacuum on the secondary side was 0.2 T at a temperature of 60 ° C.
When the pervaporation treatment was performed while maintaining the pressure at or or lower, the separation count α (H ₂ O / EtOH) was about 600, and the membrane permeation flux was about 0.30 (kg / m ² · d).

[0023]

Industrial Applicability According to the present invention, it becomes possible to economically treat and purify a waste solution of an alcohol solution, which has been conventionally disposed of as industrial waste, by utilizing energy-saving and uniform membrane separation technology. Since the used alcohol solution can be recycled, not only the discharge of industrial waste can be reduced, but also the economical efficiency in the polysaccharide refining process can be significantly increased.

[Brief description of the drawings]

FIG. 1 is a recycling system diagram of a polysaccharide purification waste solution by a membrane separation method to which the present invention is applied.

FIG. 2 is a graph showing the effect of ethanol concentration on the PEG inhibition rate.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Satoru Yamaguchi 380, Seian-cho, Kumamoto City, Kumamoto Prefecture

Claims (4)

[Claims] 1. Purification of a used alcohol solution, characterized in that the used alcohol solution for washing or purifying the polysaccharide is passed through a separation membrane to separate and remove impurities and unnecessary components mixed in the alcohol solution. -How to play. 2. The alcohol solution contains 25 to 90 w of water.
The used alcohol solution purification / regeneration method according to claim 1, which is an ethanol solution containing t%. 3. The separation membrane is an ethanol-resistant solute separation membrane which has an effective stopping property against a substance having a molecular weight of 200 to 4,000 in an alcohol solution. How to clean and recycle used alcohol solutions. 4. The alcohol solution is dehydrated by a pervaporation method using a permeation vaporization membrane having selective water permeability for water mixed in a used alcohol solution for washing or purifying polysaccharides. The used alcohol solution purification / regeneration method according to 1, 2, or 3.