JPH0211529A - Production of glycerol - Google Patents

Abstract

PURPOSE:To obtain glycerol by kneading decomposed sweet water of fatty acid oil and fat having adjusted pH and/or saponified sweet water with a visco- elastic material under high-shearing force within a range to make the visco- elastic material to be spinnable and separating and distilling the kneaded product. CONSTITUTION:Crude glycerol is produced by adjusting the pH of decomposed sweet water of fatty acid oil and fat and/or saponified sweet water preferably <=5.5 and kneading the sweet water with a visco-elastic material at 0-100 deg.C for about 2hr under high-shearing force within a range to make the visco-elastic material to be spinnable. The visco-elastic material is a semisolid substance exhibiting elastic nature in normal state and exhibiting viscosity as well as spinnability under high-shearing force. Examples of the visco-elastic material are asphalt, natural rubber, vinyl resin, polybutadiene and nylon. Preferably, sulfone group is introduced into the visco-elastic material to improve the treatment efficiency and obtain a decolored glycerol.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for producing glycerin from decomposed sweet water and/or saponified sweet water of fatty acid oils and fats. More specifically, the present invention relates to a method for producing glycerin from decomposed sweet water and/or saponified sweet water containing impurities produced as by-products when fats and oils are decomposed.

[Prior art and its challenges] In the oil and fat industry, animal and vegetable oils are decomposed,
Industries producing fatty acids and soaps are carried out on a large scale. The oil and fat decomposition industry includes the oil and fat decomposition industry, which produces natural fatty acids by heating and decomposing oils and fats together with water at high temperatures and pressures, and the saponification industry, which heats aqueous alkaline solutions and oils and fats for the purpose of producing soap.

In any industry, the by-products are decomposed sweet water from oil and fat decomposition, and saponified sweet water from soap manufacturing.
(hereinafter also simply referred to as "sweet water") is produced in large quantities as a by-product. This sweet water contains glycerin, which is important in industry, and a considerable portion of the glycerin produced is recovered and manufactured from this sweet water. For this reason, it is an industrially important issue to efficiently produce glycerin from sweet water, and an efficient method has been desired.

By the way, this sweet water is a waste liquid that is produced as a by-product when animal or vegetable oils, which originally have a complex composition, are decomposed or saponified. It also contains decomposed products of substances that coexisted in fats and oils. Therefore, it is difficult to produce glycerin due to contamination by these substances;
Therefore, the current situation is that recovery of glycerin requires complicated processes.

For example, conventional pre-concentration treatment for recovering and producing glycerin from backwater involves a coagulation-sedimentation treatment process in which organic components in well water are floated and separated using flocculants such as quicklime, soda ash, sulfuric acid, and polymer flocculants. In reality, the treatment is carried out in combination with a filtration separation step to separate aggregates, or by repeating this operation depending on the state of contamination of the sweet water.

However, even with the above pretreatment, the impurities in the by-product raw water are not necessarily completely removed, and the crude glycerin obtained by concentrating the treated raw water does not contain inorganic salts, coloring components, tar-like substances, etc. I'm here.

For this reason, further treatments are repeated to prevent decolorization and thermal decomposition during the distillation process. As this secondary treatment, for example, glycerin is produced by performing an adsorption treatment using activated carbon and then performing a distillation operation.

As described above, since the conventional process for producing glycerin from sweet water is complicated, there has been a demand for improvement in efficiency.

In addition to improving efficiency and simplifying operations, when adopting coagulation-sedimentation and activated carbon treatment processes, large amounts of treated flocculant and treated activated carbon are inevitably separated and discharged. The treatment of solid waste is also a secondary but important issue.

Furthermore, the saponified sweet water also contains the salt used in salting out to separate the soap. It would be economical if this salt could also be recovered. However, for example, in the conventional M method in which various inorganic flocculants are added, even if the salt is recovered at the concentration stage, it is necessary to process it. It could not be used again as table salt.

The object of the present invention is to easily produce high-purity glycerin from sweet water.

[Means for Solving the Problems] That is, the present invention provides a method for pulling decomposed sweet water and/or saponified sweet water of fatty acid oils and fats and a viscoelastic body under conditions where a high shear force is applied. After kneading in a range that shows stringiness, crude glycerin is separated from the treated sweet water,
The present invention provides a method for producing glycerin, which comprises distilling the glycerin.

The raw material to be treated in the method of the present invention, which will further explain the present invention below, is decomposed sweet water or saponified sweet water containing glycerin, which is a by-product during the decomposition and saponification of fatty acid oils and fats. Decomposed sweet water and saponified sweet water can also be used in combination.

Decomposition of fats and oils can be done using animal oils such as beef tallow, coconut oil, olive oil,
It is carried out for the purpose of producing fatty acids such as lauric acid, myristic acid, valmitic acid, stearic acid, and oleic acid from vegetable oils such as rice bran oil. This decomposition involves hydrolyzing the desired fat or oil by contacting it with water at high temperature and pressure. Decomposed sweet water is a by-product of this process. Saponified sweet water is a by-product when fats and oils suitable for the type of soap desired are heated and saponified with alkaline water.

Since these four sweet waters are generally alkaline, when carrying out the treatment of the present invention, it is preferable to adjust the pH to 7 or less using an acidic substance such as hydrochloric acid, sulfuric acid, nitric acid, or phosphoric acid. It is more preferable to adjust the pH to 5.5 or lower before treatment, as this will further improve the treatment efficiency.

Although there is no particular lower limit to the pH to be adjusted, a pH of 1.5 is the practical limit if corrosion of the processing equipment due to acid is taken into account.

The viscoelastic body in the method of the present invention is a substance defined as below. Here, stringiness refers to a substance that is highly viscous enough to exhibit elasticity under normal conditions with no force applied, but when kneaded under strong stress, it is difficult to draw strings due to its own viscosity. It refers to the property of being greatly deformed. A substance that exhibits both elasticity and viscosity and is deformed while exhibiting stringiness when kneaded with high shear force is called a viscoelastic body. The viscoelastic body of the present invention is defined as a substance that exhibits viscosity under high shear force, that is, under high shear force, and exhibits stringiness. Furthermore, such viscoelastic bodies are substantially insoluble or have low solubility in water and alcohols such as glycerin.

Substances that are semi-solid substances that exhibit elasticity under normal conditions but exhibit viscosity under high shear force include asphalt, coal tar pitch, rosin, natural substances such as natural rubber, polyvinyl alcohol, and glutaraldehyde. Vinyl resins such as partially crosslinked polyvinyl alcohol, partially saponified polyvinyl alcohol, polyvinyl butyral, etc., polybutene, polyisobutylene, polybutadiene, polystyrene, polyethylene, polyvinyl chloride, polyvinyl acetate, such as cyclopentadiene as the main component Such as aromatic, alicyclic or aliphatic petroleum resins obtained by polymerizing fractions mainly having 5 carbon atoms, or fractions mainly containing 9 carbon atoms containing styrene and indanes as main components. There are resinous substances polymerized by addition polymerization, and resinous substances produced by condensation polymerization such as nylon and polyester.

In order to maintain the state showing stringiness, a viscoelastic body that itself exhibits stringiness may be used, or a viscoelastic body in the region exhibiting viscosity and a viscoelastic body in the region exhibiting elasticity may be used as appropriate. They can also be mixed to maintain stringability. Further, in order to maintain even better spinnability in the kneaded state, these may be diluted with a solvent as a softener.

The solvent used as the diluent is preferably one with a high boiling point so as not to evaporate and scatter during long-time kneading.

Specifically, kerosene, light oil, turbine oil, heavy oil, etc. are exemplified.

It is more preferable to introduce an acid group, particularly a sulfone group, into the viscoelastic material used in the present invention, since the processing efficiency of the method of the present invention is improved and decolorized glycerin can be obtained.

It is sufficient if the sulfone group to be introduced is present in a very small amount. That is, it is sufficient that there are o, ooi of sulfone groups per kg of the viscoelastic material of the present invention.

There is no upper limit to the amount of sulfonic groups present and it can be selected as appropriate;
In practical terms, the upper limit is 0.5 equivalent per 1 kg of viscoelastic material.

Acid groups in viscoelastic substances 1 For example, sulfone groups may be introduced into the viscoelastic substance by chemical means such as post-modification or copolymerization, or they may be introduced into the viscoelastic substance without sulfone groups and sulfone groups. It is also possible to appropriately mix a viscoelastic body having the following properties.

As a specific example of introducing a sulfone group, for example, a conventional method used for sulfonation of aromatic hydrocarbons or olefinic hydrocarbons may be appropriately selected.

For example, methods using sulfuric acid such as sulfuric acid, concentrated sulfuric acid, fuming sulfuric acid, and sulfuric anhydride, and sulfonation using chlorosulfuric acid can be used. Alternatively, copolymerization of monomers having a sulfone group can also be used.

The method of the present invention is carried out by kneading the above-mentioned pH-adjusted sweet water and the above-mentioned viscoelastic body under high shear force. By kneading, the viscoelastic body comes into contact with the sweet water while exhibiting stringiness and being greatly deformed. As a result, organic substances other than glycerin in the sweet water are substantially absorbed by the viscoelastic body, resulting in high-purity glycerin. Sweet water containing .

In addition, in the kneading of the present invention, the viscoelastic body apparently contains a certain amount of water evenly. Water is separated only when the water holding capacity of this viscoelastic body is exceeded. Therefore, in the kneading of the present invention, the viscoelastic body which apparently evenly contains water and the excess sweet water coexist, and the viscoelastic body is kneaded while exhibiting stringiness. That will happen.

In the present invention, since the viscoelastic material is kneaded under high shear force, it is constantly subjected to a large force, the contact surface with the liquid phase is constantly renewed, and it becomes fine thread-like due to the stringiness during kneading. As the material deforms, the contact surface becomes large, and the material to be processed can be absorbed efficiently.

The contact between the viscoelastic body and the sweet water during the kneading process depends on the kneading efficiency of the equipment used for kneading, but it is usually sufficient if the viscoelastic body is brought into contact with the sweet water for about 2 hours. The temperature of the kneading treatment is not particularly limited as long as the viscoelastic body exhibits stringiness in the mixed wire state, but
Usually, the temperature is preferably between 0°C and 100°C. If the temperature is below 0°C, the water in the sweetened water to be treated will freeze, resulting in poor treatment efficiency.

Furthermore, at temperatures exceeding 100° C., in order to suppress the boiling of water in the sweetened water, the treatment equipment must be constructed to withstand pressure, which is economically uneconomical.

In order to knead while maintaining stringability under high shearing force, conventional kneaders such as single-shaft or two-wheel kneaders, Banbury mixers, etc. are used depending on the processing purpose. You can use . These kneaders can have a structure capable of heating and cooling as necessary. As described above, any kneader used in the method of the present invention may be used as long as it has a structure or mechanism that applies a high shear force to the viscoelastic body during kneading.

After kneading, if necessary, the sweet water is concentrated by a suitable separation method such as reduced pressure or heat evaporation, or the crude glycerin is separated by cooling. In the case of saponified sweet water, the salt may be further separated. For example, centrifugal filtration can be applied to separate this salt. Glycerin is produced by subjecting the crude glycerin thus obtained to appropriate distillation. This distillation is usually carried out by vacuum distillation.

[Effects of the Invention] The present invention allows glycerin, which has conventionally been produced through a complex and multi-step process, to be easily made into a high-purity state by a simple process of kneading it with a substance that has a specific physical property of viscoelasticity. The present invention provides a method that enables manufacturing.

Unlike conventional methods, there is no need to add any flocculants, so not only glycerin but also the common salt separated by concentration can be obtained with high purity.The obtained common salt can be used for salting out in the saponification process of fats and oils. It can be reused as is.

Furthermore, although the detailed mechanism is unknown, since the viscoelastic material used in the method of the present invention preferably has acid groups, various organic substances other than glycerin in sweet water can be selectively removed. Therefore, it is effective for specifically producing glycerin from sweet water.

[Example] The present invention will be explained in detail with reference to Examples below.

(Example 1) Treatment with saponified sweet water 350g of straight asphalt with a penetration degree of 60 to 80 was placed in a twin-screw kneader, and while kneading it while maintaining the temperature at 40°C to 45°C, 100g of pure water was gradually added. The viscoelastic material was then pretreated by kneading for 1 hour until water was apparently evenly incorporated.

Hydrochloric acid was added to the strongly alkaline wastewater by-product during soap production to neutralize it to adjust the pH from 5 to 4.5, and 400 g of the neutralized wastewater was added to a kneader and kneaded for 30 minutes. Next, the kneading was stopped, and the aqueous phase subjected to the treatment operation was separated and complemented by tilting the kneader.

The operations of adding, kneading, and separating this by-product wastewater were repeated 20 times to obtain 8 kg of treated water.

The obtained treated water was evaporated and concentrated under a reduced pressure of 50 to 60 n++lHg to obtain 6400 g of condensed water and 1600 g of a mixture of common salt and glycerin as a concentrate.

Next, by centrifugal filtration operation, 880 g of salt and 720 g of
A pale yellow crude glycerin was obtained. The obtained common salt had a slight yellow color.

The pale yellow crude glycerin was further precisely distilled under reduced pressure of 2 to 3 mmHH to obtain 680 g of clear, colorless, and odorless glycerin.

(Example 2) Treatment of decomposed sweet water Similarly to Example 1, 350 g of straight asphalt with a penetration degree of 60 to 80 was placed in a two-wheeled kneader, and the temperature was set at 4.
100 g of pure water was gradually added while kneading while maintaining the temperature at 0 to 45° C., and kneading was continued for about 1 hour until the water was apparently evenly incorporated, thereby pretreating the viscoelastic body.

The decomposed sweet water of fats and oils contains a small amount of suspended matter, has a black-reddish-brown color, is strongly alkaline, and has a characteristic odor. Similarly to Example 1, use hydrochloric acid to adjust the pH to 5 to 4.
．． Adjusted to 5. By neutralizing the pH, a large amount of insoluble components were separated and precipitated, and the neutralized wastewater turned into a completely opaque brown liquid.

400 g of neutralized waste water was put into a kneader and kneaded for one hour in the same manner as in Example 1. Next, the kneading was stopped, and the aqueous phase that had undergone the treatment operation was separated and complemented by tilting the kneader.

The operations of adding, kneading, and separating this neutralized wastewater were repeated 20 times to obtain 8 kg of treated water.

The obtained treated water was evaporated and concentrated under a reduced pressure of 50 to 60 Ilm) to obtain 6500 g of condensed water and 1500 g of a mixture of common salt and glycerin as a concentrate.

Through the centrifugal filtration operation, 650 g of common salt and 850 g of pale brown crude glycerin were obtained. The obtained common salt had a slight yellow color and was sufficient to be reused for salting out.

The light yellow crude glycerin was further distilled under a reduced pressure of 2 to 3 mmHg to obtain 730 g of colorless and transparent glycerin.

(Example 3) Tetrax IT (manufactured by Nippon Petrochemical Co., Ltd.), which is an isobutylene polymer treated with a sulfonated viscoelastic material
Product name, viscosity average molecule m 110000) 400 to n-
Dissolved in 1.5 liters of hexane, temperature 50-60℃
Sulfonation was carried out by gradually adding 30% fuming sulfuric acid while maintaining the temperature. Fuming sulfuric acid was added to Tetrax IT in a 5-fold molar amount as 503. Thereafter, the reaction was allowed to proceed for 2 hours, and after the reaction was completed, 1 liter of hexane was further added, and the waste acid layer was separated by standing and washed until the washing water became neutral.

Thereafter, the solvent hexane was distilled off under reduced pressure to obtain sulfonated polyisobutylene. Sulfonation rate is 65 mol%
Met.

t 50 g of Tetrax 3T (manufactured by Nippon Petrochemical Corporation, trade name, viscosity average molecular weight 30,000), 150 g of Tetrax IT, and 30 g of the sulfonated product obtained above were placed in a twin-screw kneader, and the temperature was 40°C. 100 g of pure water was gradually added while kneading the mixture while maintaining the temperature at 45 DEG C., and the mixture was kneaded for about 1 hour until the water was apparently included in the upper layer to pre-treat the viscoelastic body.

Neutralized wastewater of by-product wastewater during soap production used in Example 1 (4
00g) was added to the kneader and kneaded for 40 minutes.

After kneading, the neutralized wastewater was treated in the same manner as in Example 1 and distilled to produce 700 g of transparent, colorless and odorless glycerin.

(Comparative Example 1) Coagulation and Precipitation Treatment of Saponified Sweet Water Similarly to Example 1, hydrochloric acid was added to neutralize the by-product wastewater during soap production, which was strongly alkaline, and the pH was adjusted from 5 to 4.5. 50 g of a 20% aqueous solution of band sulfate and 100 g of a flocculant (commercially available flocculant that is a 2% aqueous solution) were added to 10 kg of wastewater after neutralization, and after mixing with gentle stirring for 10 minutes, the mixture was allowed to stand for 2 hours to separate. . The grown aggregates were separated into a clear supernatant and aggregates by centrifugation, and the supernatant was further filtered to obtain treated wastewater.

The treated water was evaporated and concentrated under reduced pressure of 50 to 60 mmHH.
900 g of condensed water and 2100 g of a mixture of common salt and glycerin as a concentrate were obtained. 1 by centrifugal filtration operation
050 g of common salt and 1050 g of pale brown crude glycerin were obtained. The obtained common salt clearly contained a coloring component and had a brownish color.

Even when the light brown crude glycerin was further precisely distilled under reduced pressure of 2 to 3 nmHH, decomposition occurred due to heating, and the obtained glycerin was yellowish brown and had an unpleasant off-odor.

Naturally, these items had no commercial value.

(Comparative Example 2) Treatment of Decomposed Sweet Water Similarly to Example 2, hydrochloric acid was added to neutralize the by-product wastewater, which is decomposed sweet water exhibiting strong alkalinity, and the pH was adjusted from 5 to 4.5. 100 g of a 20% aqueous solution of band sulfate and 200 g of a flocculant (commercially available flocculant that is a 2% aqueous solution) were added to 10 liters of wastewater after neutralization, and after mixing with gentle stirring for 10 minutes, the mixture was allowed to stand for 2 hours to separate. . The grown aggregates were separated into a clear supernatant and aggregates by centrifugation, and the supernatant was further filtered to obtain treated wastewater.

The treated water was evaporated and concentrated under reduced pressure of 50 to 60 mmHH.
200 g of condensed water and 1800 g of a mixture of common salt and glycerin were obtained as a concentrate. 82 by centrifugation operation
The mixture was separated into a lower layer mainly containing 0 g of common salt and an upper layer mainly containing 980 g of dark brown crude glycerin. The resulting lower layer, which mainly contains common salt, was recovered only as a black-brown muddy substance.

Even when the dark brown crude glycerin was further distilled under a reduced pressure of 2 to 3 mMHg, decomposition occurred due to heating, and the obtained glycerin was only brown in color and had an unpleasant gastric odor.

Both the recovered salt and glycerin had no commercial value.

Patent applicant: Japan Petrochemical Co., Ltd.

Claims (1)

[Claims] (1) A range in which the viscoelastic body exhibits stringiness under conditions where a high shear force is applied to decomposed sweet water and/or saponified sweet water of fatty acid oils and fats whose pH has been adjusted appropriately and a viscoelastic body. 1. A method for producing glycerin, which comprises separating crude glycerin from the treated sweet water and distilling it after kneading the sweet water.