JP4374219B2 - Chemical recycling method for waste oil - Google Patents

Description

The present invention relates to a method for chemical recycling of waste oils and fats.
The world's production of fats and oils is about 85 million tons per year (1993), and the consumption of fats and oils in Japan is about 2.8 million tons per year, of which about 23.5 million tons are used for food. Yes.
According to estimates, in Japan, the annual amount of waste oil discarded from oil processing plants, food manufacturing plants, restaurants, general households, etc. reaches about 1 million tons. Of the waste oil and fat, only 100,000 tons corresponding to 10% of the waste oil and fat are recycled as raw materials such as soap. 900,000 tons, equivalent to 90% of waste oil and fat, are not collected but discarded as waste, or mixed with other waste and sent to a waste treatment plant where it is incinerated with combustible waste or incombustible. It is disposed of together with garbage and disposed of in large quantities.
The present invention is a method of recycling waste oils and fats, which are recycled to a fuel oil or a refined fatty acid alkyl ester that can be used as a chemical raw material, a refined glycerin that can be used as an industrial chemical raw material, or a fuel alternative to heavy oil. Regarding the method.

Conventionally, there is a technique for recycling waste oil and fat to fatty acid alkyl esters (see, for example, Patent Documents 1 and 2).
In these recycling technologies, waste oils and fats are mixed with alcohol and an alkali catalyst, this mixture is subjected to a transesterification reaction, and the resulting reaction product is allowed to stand. The light liquid is separated and purified to a fatty acid alkyl ester.

However, the conventional waste oil recycling technology has the following problems (i) to (ii).
(I) The light liquid after phase separation of the reaction product obtained by the transesterification reaction purifies the fatty acid alkyl ester as the main component and recycles it into a high-purity fatty acid alkyl ester. However, heavy liquid contains many impurities other than the main component glycerin and cannot be used for industrial chemical raw materials or fuels.
(Ii) There is no easy way to recycle waste oil to high purity glycerin.

Japanese Patent Laid-Open No. 10-245586 Japanese Patent Laid-Open No. 10-231497

  SUMMARY OF THE INVENTION In view of the above circumstances, the present invention provides a method for chemical recycling of waste oil and fat that can be recycled into high-purity fatty acid alkyl ester, high-purity glycerin and heavy oil substitute fuel by a relatively simple and inexpensive processing means. For the purpose.

The chemical recycling method for waste oils and fats of the first invention is a method for chemically recycling waste oils and fats, which is obtained by transesterifying a mixture of the waste oils and fats with an alcohol and an alkali catalyst, and performing the ester exchange reaction. The obtained reaction product is phase-separated into a heavy liquid and a light liquid, the heavy liquid is taken out, and water and alcohol are added to the heavy liquid to adjust the components. An inorganic acid is added so that the pH of the adjustment solution is 3.0 to 7.0, the inorganic salt is removed from the adjustment solution to which the inorganic acid has been added, and the adjustment solution from which the inorganic salt has been removed is distilled. Water and alcohol are removed, the adjustment solution from which the water and alcohol have been removed is distilled, and the distillate of the adjustment solution is phase-separated into a second heavy liquid and a second light liquid.
The chemical recycling method for waste oils and fats of the second invention is a method for chemically recycling waste oils and fats, which is obtained by transesterifying a mixture of the waste oils and fats with an alcohol and an alkali catalyst, and performing the ester exchange reaction. Water and alcohol were added to the reaction product to adjust the components, and an inorganic acid was added to the adjusted solution so that the adjusted solution had a pH of 3.0 to 7.0. The inorganic salt is removed from the added adjustment solution, the adjustment solution from which the inorganic salt has been removed is distilled, water and alcohol are removed, and the adjustment solution from which the water and alcohol have been removed is distilled and the adjustment is performed. The distillate of the solution is phase-separated into a heavy liquid and a light liquid.
The chemical recycling method for waste oil according to a third aspect of the present invention is characterized in that, in the first or second aspect, the alcohol concentration of the adjusted solution having the components adjusted is 20 to 80% by weight.
The method for chemical recycling of waste oils and fats of the fourth invention is characterized in that, in the first or second invention, the step of adding the inorganic acid is performed at a temperature of 5 to 60 ° C.

The function and effect of the invention of claim 1 will be described with reference to FIG.
The invention according to claim 1 sequentially executes the following steps (1) to (8).
(1) Through the transesterification step (S11), triglyceride, diglyceride and monoglyceride contained in the waste oil and fat are converted into fatty acid alkyl ester and glycerin.
(2) By the phase separation step (S12), the reaction product can be phase-separated into a light liquid mainly composed of fatty acid alkyl ester and a heavy liquid composed mainly of glycerin.
(3) The component adjustment step (S21) can reduce the viscosity of heavy liquid and prevent the suspension of inorganic salts generated in the subsequent inorganic acid addition step, thus reducing the load on the glycerin purification step. it can. For this reason, the adjustment solution in which an inorganic metal salt tends to precipitate by a subsequent acid addition step can be obtained.
(4) In the acid addition step (S22), the alkali catalyst contained in the adjustment solution is neutralized, and the soap contained in the adjustment solution is acid-decomposed, so that the adjustment solution contains almost no alkali catalyst or soap. Can be converted to In addition, since the metal salt produced by the acid addition step is insoluble in the fatty acid alkyl ester, it can be precipitated as a solid metal salt crystal or a metal salt hydrate crystal. Furthermore, by adjusting the pH of the solution so that the pH of the adjustment solution is 3.0 to 7.0, the alkali catalyst and fatty acid soap contained in the adjustment solution can be reliably decomposed, so that a high-purity fatty acid alkyl ester can be produced, and the container Corrosion can be prevented.
(5) By the inorganic salt removal step (S23), the solid inorganic salt contained in the adjustment solution can be separated from the liquid phase of the heavy liquid.
(6) Water and alcohol contained in the adjustment solution can be removed by the first distillation step (S24).
(7) Glycerin and fatty acid alkyl ester contained in the adjustment solution can be distilled by the second distillation step (S25). The adjustment solution remaining without distillation is very close to the properties of heavy oil.
(8) The distillate of the adjustment solution can be separated into the second light liquid and the second heavy liquid by the phase separation step (S26).
The following effects can be obtained by sequentially executing the steps (1) to (8).
The separated second light liquid has extremely low residual concentrations of unreacted alcohol, water, and glycerin, and thus it is possible to obtain a high-purity fatty acid alkyl ester that can be used as a diesel fuel without being purified. In addition, the separated second heavy liquid has a very low residual impurity concentration, and high-purity glycerin that can be used as it is as an industrial chemical raw material can be obtained without purification.
Therefore, the heavy liquid mainly composed of glycerin, which is generated as a by-product in the refining process for refining waste oils and fatty acids to fatty acid alkyl esters, can be used for diesel fuel, chemical raw materials, fatty acid alkyl esters, industrial chemical raw materials, etc. It can be recycled into heavy oil alternative fuel that can be used for refined glycerin, boiler fuel, etc. and can be replaced with heavy oil.
The effect of the invention of claim 2 will be described with reference to FIG.
The invention according to claim 2 sequentially executes the following steps (1) to (7).
(1) Through the transesterification step (S11), triglyceride, diglyceride and monoglyceride contained in the waste oil and fat are converted into fatty acid alkyl ester and glycerin.
(2) The component adjustment step (S21) reduces the viscosity of the reaction product and prevents the suspension of the inorganic metal salt generated in the subsequent inorganic acid addition step. Can be reduced. For this reason, the adjustment solution which an inorganic salt tends to precipitate by a subsequent acid addition step can be obtained.
(3) The acid addition step (S22) neutralizes the alkali catalyst contained in the adjustment solution and decomposes the soap contained in the adjustment solution, so that the adjustment solution containing almost no alkali catalyst or soap is used. Can be converted. Moreover, since the metal salt produced by the acid addition step is insoluble in the fatty acid alkyl ester, it can be precipitated as a solid metal salt crystal or a metal salt hydrate crystal. Furthermore, by adjusting the pH of the solution so that the pH of the adjusted solution is 3.0 to 7.0, the alkali catalyst contained in the adjusted solution can be reliably neutralized, so that a high-purity fatty acid alkyl ester can be produced, and corrosion of the container can be prevented. Can be prevented.
(4) By the inorganic salt removal step (S23), the solid inorganic salt contained in the adjustment solution can be separated from the liquid phase.
(5) Water and alcohol contained in the adjustment solution can be removed by the first distillation step (S24).
(6) By the second distillation step (S25), glycerin and fatty acid alkyl ester contained in the adjustment solution can be distilled. The adjustment solution remaining without distillation is very close to the properties of heavy oil.
(7) The distillate of the adjusted solution can be separated into a light liquid and a heavy liquid by the phase separation step (S26). Since the acid-added reaction product does not contain soap, in the phase separation step, the reaction product is reliably converted into a light liquid mainly composed of fatty acid alkyl ester and a heavy liquid mainly composed of glycerin, and Phase separation can be performed quickly.
The following effects can be obtained by sequentially executing the steps (1) to (7).
The separated light liquid has extremely low residual concentrations of unreacted alcohol, water and glycerin, and it is possible to obtain a high-purity fatty acid alkyl ester that can be used as it is as a diesel fuel or a chemical industrial raw material without being purified. Further, the separated heavy liquid has a very low residual concentration of impurities, and it is possible to obtain high-purity glycerin that can be used as it is as an industrial chemical raw material without purification.
Therefore, the waste oil and fat can be recycled into a fuel oil alternative fuel that can be used as a fatty acid alkyl ester that can be used as a diesel fuel or a chemical raw material, a high-purity purified glycerin that can be used as an industrial chemical raw material, a boiler fuel, or the like.
According to the invention of claim 3, the dissolution and suspension amount of the inorganic salt generated in the acid addition step, which is a subsequent step, is reduced, the removability of alkali metal ions and the like is improved, and glycerin purification The load in steps can be reduced.
According to the invention of claim 4, since the dissolution and suspension amount of the metal salt in the fatty acid alkyl ester is small, and the metal salt can be easily separated from the fatty acid alkyl ester, which is economical. Is preferred.

Next, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a processing block diagram in the first chemical recycling method for waste oil according to the present invention. As shown in the figure, the first chemical recycling method for waste oil and fat according to the present invention uses heavy oil alternative fuel 17 and refined glycerin for heavy liquid 22 (waste glycerin) generated in the process of refining waste oil and fat 1 to fatty acid alkyl ester 20. 18 and fatty acid alkyl ester 19.

The waste oils and fats 1 are vegetable oils such as soybean oil, rapeseed oil, sunflower oil, cottonseed oil, coconut oil, sesame oil, peanut oil, coconut oil, and animal oils such as beef fat, pork fat, horse fat, fish oil, and whale oil, and used thereof. Waste oil can be used. These fats and oils may be used alone or as a mixture of two or more. Used waste oil, for example, waste oil and fat discarded from oil processing factory, food manufacturing factory, restaurant, general household, etc., oil and fat residue such as oil cake in edible oil manufacturing process, used as lubricating oil for metal hot rolling process Waste oils and fats of vegetable oils, waste oils and fats generated in the manufacturing process of processed oils and fats such as margarine, shortening, etc., returnable edible oils and fats such as defective products and expired foods, and animal oils and fats generated in the processing process of edible oil and fish meat may be used. The content of the free fatty acid contained in the fat 1 is not particularly limited, but is preferably 5% or less.
In addition, it is good to remove impurities, such as solid substances, such as garbage and cooking grounds, water, and a free fatty acid, which are contained in the waste oil and fat 1, as a pretreatment for performing a transesterification reaction. In this case, the transesterification reaction can be performed efficiently, which is preferable.

  The alcohol 2 is preferably a monohydric alcohol having 1 to 10 carbon atoms such as methanol, ethanol or propanol. The water content of these alcohols is not particularly limited, but is preferably 1% or less.

  The alkali catalyst 3 is not particularly limited as long as it is an alkaline substance showing activity in the transesterification reaction, such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, potassium alcoholate, sodium alcoholate.

Now, the first chemical recycling method for waste oil according to the present invention will be described in the order of steps.
First, a reaction product 10 can be obtained by subjecting a mixture in which the oil 1, the alcohol 2 and the alkali catalyst 3 are mixed to each other (S 11). The transesterification reaction may be carried out under reaction conditions usually used, for example, reaction conditions of a temperature around 65 ° C. at normal pressure.
The triglyceride, diglyceride and monoglyceride contained in the fat 1 are converted into fatty acid alkyl ester and glycerin by the transesterification reaction (Formula 1), and these components are contained in the reaction product 10. In addition to the above components, the reaction product 10 contains an alkali catalyst, alcohol, moisture, and the like.

(Formula 1)

Next, the reaction product 10 is phase-separated into a light liquid 21 and a heavy liquid 22 (S12).
When the reaction product 10 is allowed to stand for a certain period of time, the reaction product 10 is separated into two phases of a light liquid (upper layer) mainly composed of fatty acid alkyl ester and a heavy liquid (lower layer) mainly composed of glycerin.
In addition, this phase separation step S12 may be separated not only by standing but also by a centrifugal separator, or a combination of these separation methods.

  For example, when the reaction product 10 is separated by a centrifuge, the reaction product 10 is separated into a light liquid mainly composed of fatty acid alkyl and a heavy liquid mainly composed of glycerin using a desk type centrifuge. Can do.

  The light liquid 21 can be purified to a high purity fatty acid alkyl ester 20 by purification (S13).

Next, the component adjustment step S21 will be described.
The heavy liquid 22 is taken out, and water 11 and alcohol 12 are added to the heavy liquid 22 to obtain an adjustment solution 23. The component of the alcohol concentration in the adjustment solution 23 is adjusted to 20 to 80% by weight (S21). The components are preferably adjusted to 40 to 70% by weight, more preferably 50 to 60% by weight.
When the alcohol concentration in the adjustment solution 23 exceeds 80% by weight, it is not economical. When the alcohol concentration is less than 20% by weight, the effect of reducing the solubility of the inorganic salt in the adjustment solution 23 by the alcohol is reduced. Impurity removal is reduced.
Therefore, by adjusting the alcohol concentration to 20 to 80% by weight, the viscosity of the adjustment solution 23 can be reduced economically and the suspension of the metal salt fine particles can be prevented, thereby reducing the load on the glycerin purification step. be able to. For this reason, the adjustment solution 23 which an inorganic salt tends to precipitate can be obtained by a subsequent acid addition step. As a result, the dissolution and suspension amount of the inorganic salt generated in the acid addition step S22, which is a subsequent process, is reduced, and the removability of alkali metal ions and the like is improved. The load in the glycerin purification step such as can be reduced.

In addition, the water concentration of the adjustment solution 23 is adjusted to 0.5 to 10% by weight, preferably 1.0 to 5.0% by weight.
When the water concentration of the adjustment solution 23 exceeds 10% by weight, inorganic salts such as mirabilite dissolve in water, and a large amount of inorganic salt produced in the acid decomposition step dissolves in the prepared glycerin solution. Such an increase in the amount of impurities such as impurities is undesirable.
On the other hand, when the water concentration of the adjustment solution 23 is less than 0.5% by weight, the crystal grain size of the inorganic salt generated in the acid decomposition step becomes small and the separability deteriorates.
By adjusting the water concentration to 0.5 to 10% by weight, it is possible to increase the crystal grain size of the inorganic salt produced in the acid decomposition step, and the produced inorganic salt is separated and removed by, for example, filtration. The separability in the case is improved.

When the alcohol concentration of the heavy liquid 22 is 20 to 80% by weight, it is not always necessary to add alcohol or water to adjust the components.
Furthermore, the component adjustment of the alcohol concentration may be performed after adding the alcohol before the transesterification so that the alcohol concentration of the heavy liquid 22 is 20 to 80% by weight. In this case, since the transesterification is carried out in the presence of excess alcohol, the reaction rate and the equilibrium reaction conversion rate are increased, and a high-quality fatty acid alkyl ester can be obtained.
In addition, the water concentration may be adjusted by adding water after the ester exchange so that the water concentration of the heavy liquid 22 is 0.5 to 10% by weight, and then performing phase separation.

Next, the acid addition step S22 will be described.
An inorganic acid 13 such as sulfuric acid or phosphoric acid is added to the adjustment solution 23 so that the pH of the adjustment solution 23 is 3.0 to 7.0 (S22). More preferably, the pH should be 5.0 to 7.0.
In addition, after adding the inorganic acid 13, it is good to stir suitably.

By adding the inorganic acid 13 to the adjustment solution 23, a chemical reaction of neutralization reaction and acid decomposition occurs.
By the former neutralization reaction, the alkali catalyst contained in the adjustment solution 23 is neutralized to become a metal salt and water. The following chemical reaction formula 3 shows a neutralization reaction when the alkali catalyst is potassium hydroxide and the inorganic acid 13 is sulfuric acid as an example.
(Chemical reaction formula 3)
2KOH + H ₂ SO ₄ → K ₂ SO ₄ + 2H ₂ 0

By the latter acid decomposition, the soap (fatty acid salt) contained in the adjustment solution 23 is acid-decomposed into fatty acid and metal salt. The following chemical reaction formula 4 shows acid decomposition when the inorganic acid 13 is sulfuric acid.
(Chemical reaction formula 4)
_{2R-COOK + H 2 SO 4} → 2R-COOH + K 2 SO 4

  Since the metal salt produced by the neutralization reaction and acid decomposition is insoluble in an organic solvent such as alcohol, it precipitates as a solid metal salt crystal or a metal salt hydrate crystal.

In the acid addition step S22, the pH is adjusted so that the pH of the adjustment solution 23 is 3.0 to 7.0 for the following reason.
When the pH of the adjustment solution 23 exceeds 7.0, neutralization of the alkali catalyst and decomposition of the fatty acid soap are insufficient, and bubbles are violently formed in the distillation tower during alcohol recovery, making alcohol recovery difficult.
Conversely, when the pH of the adjustment solution 23 is less than 3, fatty acids generated by acid decomposition after alcohol recovery are easily dissolved in the glycerin layer, and the load in the glycerin purification process increases due to excess acid. .
Therefore, by adjusting the pH so that the pH of the adjustment solution 23 is 3.0 to 7.0, the alkali catalyst contained in the adjustment solution 23 can be reliably neutralized and the fatty acid soap can be reliably decomposed. It is preferable because a fatty acid alkyl ester having a high purity can be produced and there is no fear of container corrosion.

  As the inorganic acid 13 added to the adjustment solution 23, one or more acids selected from the group consisting of sulfuric acid, phosphoric acid and hydrochloric acid can be used.

The temperature in the acid addition step S22 is 5 to 60 ° C, preferably 5 to 30 ° C.
When the temperature exceeds 60 ° C., the solubility in the adjustment solution 23 of the inorganic salt generated by acid decomposition increases, and the load in the subsequent process increases.
Conversely, when the temperature is lower than 5 ° C., it can be said that the amount of the inorganic salt dissolved in the prepared glycerin solution is small, which is advantageous, but it is not economical to operate at such a temperature in an actual facility.
Therefore, the temperature in the acid addition step S22 is preferably 5 to 60 ° C. In this case, the inorganic salt is less dissolved in the fatty acid alkyl ester, and the inorganic salt can be easily separated from the fatty acid alkyl ester, which is economical. .

Next, the inorganic salt removal step S23 will be described.
By filtering or centrifuging the adjustment solution 23, for example, the crystals of the inorganic salt 14 can be separated and removed from the adjustment solution 23, so that it is possible to prevent the quality of glycerin from being deteriorated.
The separated inorganic salt 14 can be used as an agricultural fertilizer or a chemical raw material.

Next, the first vacuum distillation step S24 will be described.
The adjustment solution 23 is placed in a distillation tower and distilled under reduced pressure (S24). The vacuum distillation may be carried out using a batch-type or continuous-type apparatus under conditions where the temperature is in the range of room temperature to 120 ° C, preferably 60 to 90 ° C, and the pressure is in the range of 1 to 760 mmHg, preferably 1 to 60 mmHg. .
According to the first vacuum distillation step S24, the alcohol 16 and the water 15 can be separated and removed from the adjustment solution 23 from which the inorganic salt 14 has been separated and removed.

The alcohol 16 can be separated and recovered by cooling the vapor mixture of the vaporized alcohol 16 and water 15. In addition, the mixed steam of the alcohol 16 and the water 15 can be cooled to a temperature not lower than the boiling point of the alcohol and not higher than the boiling temperature of the water, and only the water vapor can be condensed and recovered as liquid water 15.
Since the recovered alcohol 16 has an extremely low water content, it can be reused as a raw material for preparing a catalyst-containing alcohol solution or as an alcohol 12 for adjusting the components of the heavy liquid 22. Further, since the recovered water 11 is almost free of impurities, it can be used for process water or may be discharged to the outside as it is.

Next, the second vacuum distillation step S25 will be described.
By adjusting the temperature of the distillation tower in which the adjustment solution 23 is stored to a predetermined temperature (170 to 360 ° C.), the adjustment solution 23 can be heated and distilled at this predetermined temperature (S25).
For example, when obtaining a fatty acid alkyl ester as a diesel fuel oil, it is necessary to distill the fatty acid alkyl ester having a boiling point temperature range of 170 to 360 ° C. For this reason, what is necessary is just to set the distillation temperature and pressure so that the fatty-acid alkylester of the boiling point temperature range 170-360 degreeC may evaporate. Usually, in order to prevent thermal decomposition of the fatty acid alkyl ester, the temperature is set as low as possible and the pressure is set low. For example, when the temperature is set to 250 ° C. and the pressure is set to 10 mmHg, a fatty acid alkyl ester having a boiling range suitable as the diesel fuel oil can be distilled.
On the other hand, since the boiling point of glycerin at atmospheric pressure is 290 ° C., the distillation conditions of the fatty acid alkyl ester described above result in distilling together with the fatty acid alkyl ester, and eventually a mixture of glycerin and fatty acid alkyl ester is obtained. It will be.

  According to the second reduced pressure distillation step S25, the adjustment solution 23 from which the alcohol 16 and the water 15 are separated and removed can be distilled and separated into a mixture of fatty acid alkyl ester and glycerin and distillation residue. The adjustment solution 23 heated to a predetermined temperature is placed under a reduced pressure to evaporate the glycerin and the fatty acid alkyl ester, and the vapor is cooled to obtain a liquid mixture of glycerin and the fatty acid alkyl ester.

  The distillation residue remaining in the second vacuum distillation step S25 is mainly composed of unreacted monoglyceride, diglyceride, triglyceride, fatty acid alkyl ester having a high boiling point, a small amount of glycerin, a glycerin derivative and a glycerin polycondensate, and its flash point. Since the characteristics such as kinematic viscosity and pour point are close to those of A heavy oil or C heavy oil, they can be used as heavy oil substitute fuel 17 such as boiler fuel.

Next, the second phase separation step S26 will be described.
The distillate obtained from the second vacuum distillation step S25 can be separated into glycerin 18 and fatty acid alkyl ester 19 using the difference in specific gravity and polarity between glycerin and fatty acid alkyl ester. Separation is performed by natural sedimentation separation or mechanical separation applying centrifugal force. When the natural sedimentation separation method is used, for example, when the mixture of glycerin and fatty acid alkyl ester is cooled to 100 ° C. or lower and allowed to stand for 1 to 8 hours, the fatty acid alkyl ester phase (upper layer) and glycerin phase (lower layer) are separated. , Purified fatty acid alkyl ester 19 and purified glycerin 18 are obtained.
According to the second phase separation step S26, the mixture of glycerin and fatty acid alkyl ester obtained from the second vacuum distillation step S25 is separated into glycerin and fatty acid alkyl ester, and finally purified fatty acid alkyl ester 19 and purified glycerin. 18 can be obtained.

  The purified fatty acid alkyl ester 19 thus obtained has a higher purity than that of the fatty acid alkyl ester purified by a conventional purification method, so that it can satisfy, for example, the standard ASTM PS121-99 for biodiesel fuel oil in the United States. The liquid 21 can be handled in the same manner as the purified fatty acid alkyl ester from the purification treatment S13.

  In addition, purified glycerin 18 can meet, for example, JIS standard K3351-95 for industrial glycerin, pharmaceuticals, various cosmetics, toiletries, tobacco moisturizers, foodstuffs, solvents, printing inks, toothpaste, fragrances, explosives, Freezing agent, pharmaceutical, confectionery, ink, cellophane, transparent soap, fiber lubricant, bonding agent, photographic paper, polish, toothpaste, tobacco, surfactant, paint, alkyd resin, polyurethane, monoglyceride, capsule, alkyd resin, Can be used for applications such as polyurethane, cellophane, film, mouthwash, ink, fragrance, tobacco, tobacco filter, gunpowder, antifreeze, soap, fiber, paper, solvent, condenser.

Next, the second chemical recycling method of the present invention will be described.
FIG. 2 is a processing block diagram in the second chemical recycling method of the present invention. As shown in the figure, the second chemical recycling method of the present invention is a method of recycling waste oil 1 as a raw material into heavy oil substitute fuel 17, refined glycerin 18 and fatty acid alkyl ester 19.

  About the waste oil and fat 1, the alcohol 2, the alkali catalyst 3, the water 11, the alcohol 12, and the inorganic acid 13 which are raw materials, the thing substantially the same as what was used with the 1st chemical recycling method should just be used.

  In the transesterification step S11, as in the transesterification step in the first chemical recycling method, the mixture of the oil 1, the alcohol 2 and the alkali catalyst 3 is mixed under a commonly used reaction condition such as normal pressure. What is necessary is just to make it transesterify on the reaction conditions of the temperature around 65 degreeC (S11). The reaction product 10 can be obtained by the transesterification step S11.

In the second chemical recycling method, the reaction product 10 is not phase-separated, the component adjustment step S21, the acid addition step S22, the inorganic salt removal step S23, the first vacuum distillation step S24, the second The vacuum distillation step S25 and the phase separation step S26 are executed in this order.
Steps S21 to S26 in the second chemical recycling method are substantially the same as steps S21 to S26 in the first chemical recycling method.

  Therefore, the purified fatty acid alkyl ester 19 obtained by the second chemical recycling method has the same properties as the purified fatty acid alkyl ester 19 obtained by the first chemical recycling method, that is, higher than the fatty acid alkyl ester purified by the usual purification method. Because of its purity, it meets, for example, the standard ASTM PS121-99 for American biodiesel fuel oil.

  In addition, the purified glycerin 18 obtained by the second chemical recycling method can satisfy, for example, JIS standard K3351-95 for industrial glycerin, pharmaceuticals, various cosmetics, toiletries, tobacco moisturizers, foods, solvents, printing inks. , Toothpaste, fragrance, gunpowder, antifreeze, pharmaceutical, confectionery, ink, cellophane, transparent soap, fiber lubricant, binder, photographic paper, polish, toothpaste, tobacco, surfactant, paint, alkyd resin, polyurethane , Monoglyceride, capsule, alkyd resin, polyurethane, cellophane, film, mouthwash, ink, fragrance, tobacco, tobacco filter, gunpowder, antifreeze, soap, fiber, paper, solvent, condenser, etc.

  The distillation residual oil remaining in the second vacuum distillation step S25 in the second chemical recycling method is mainly composed of unreacted monoglyceride, diglyceride, triglyceride, fatty acid alkyl ester having a high boiling point, a small amount of glycerin, a glycerin derivative and a glycerin polycondensate. Thus, the flash point, kinematic viscosity, pour point and other characteristics are close to those of A heavy oil or C heavy oil, so that it can be used as a heavy oil substitute fuel 17 such as boiler fuel.

Next, examples of the chemical recycling method of the present invention will be described.
[Example 1]
In Example 1, waste edible oil 1 (acid value 3.4 mgKOH / g, iodine value 112, water content 0.9%, ash content 1.3%) recovered from general households was used as the raw material waste oil 1.
As the alcohol 2, methanol (purity 99.8%) was used.
As the alkali catalyst 3, industrial potassium hydroxide (KOH content: 95%) was used.
9.66 parts by weight of the alkali catalyst 3 was mixed with 100 parts by volume of the alcohol 2 and stirred to prepare a mixed solution of the alcohol and the alkali catalyst.

First, before the transesterification reaction, the following pretreatment was performed on the waste oil 1.
The waste oil 1 was subjected to primary filtration with a 0.5 × 0.5 mm wire mesh, and then filtered with a filtration device comprising a mesh 40 polyester long fiber cartridge to remove solid impurities contained in the waste oil 1. The waste oil 1 was allowed to stand at room temperature for 4 hours, so that water having a saturation solubility or higher in the waste oil was settled, and the water was separated and removed. The waste oil / fat 1 was vacuum dehydrated and liberated fatty acid by stirring for 40 minutes while maintaining the waste oil / fat at 70 ° C. in a sealed container having a pressure of 5 mmHg.

Next, a transesterification reaction was performed.
A mixed solution of 16.7 parts by volume of the alcohol and the alkali catalyst was mixed with 100 parts by volume of the pretreated waste oil and fat, and this mixed solution was stirred at a temperature of 65 ° C. for 20 minutes to perform a transesterification reaction. .

The reaction product 10 obtained by the transesterification reaction is allowed to stand for 4 hours, and is phase-separated into a light liquid (supernatant) 21 containing fatty acid methyl ester as a main component and a heavy liquid (supernatant) 22 containing glycerin as a main component. I let you.

The light liquid 21 was adsorbed and purified by passing it through a column packed with activated clay (average particle size 1 mm, specific surface area 250 cm ² / g, free acid value 2.0 KOH mg / g) at a space velocity of 2 h ⁻¹ . . Next, the light liquid 21 treated with the activated clay was stirred for 20 minutes while being kept at 20 mmHg and 60 ° C. in an evaporator, and the remaining methanol was removed by vacuum flash distillation. Next, purified fatty acid methyl ester 20 was obtained by purifying light liquid 21 from which methanol had been removed by removing a small amount of solid substances such as activated clay contained in light liquid 21 with a centrifugal separator having a centrifugal effect of 3000 G.

  FIG. 3 is a composition table of the heavy liquid 22 of Example 1. As shown in the table, heavy liquid 22 of Example 1 includes glycerin (46.7%), methanol (6.0%), fatty acid methyl ester (35.4%), soap (3.0%), potassium hydroxide (5.0%). , Water (1.7%), and other unknowns (2.2%).

About this heavy liquid 22, it processed in the following order.
First, methanol and water were added to the heavy liquid 22, and the components were adjusted so that the methanol concentration became 50% and the water concentration became 3%, whereby an adjustment solution 23 was obtained.
Next, 97% concentrated sulfuric acid was added dropwise at a constant rate until the final pH of the adjusting solution 23 reached 5.0 while stirring the solution while maintaining the temperature of the adjusting solution 23 at 15 ° C.

  While this adjustment solution 23 was sucked under reduced pressure, the quantitative filter paper No. The crystals of potassium sulfate were filtered off by passing through 5C.

  The filtered adjustment solution 23 was distilled under reduced pressure at a pressure of 20 mmHg, and the first distillation of methanol (distillation temperature 43 ° C.) and water (distillation temperature 65 ° C.) was performed.

Furthermore, the adjustment solution 23 after the first distillation was subjected to a second distillation at a pressure of 5 mmHg to obtain a distillate of glycerin and fatty acid methyl ester (distillation temperature 140 ° C. to 200 ° C.).
About the distillation residual oil after the 2nd distillation, it recovered as a heavy oil substitute fuel 17 from the distillation kettle as it was.

Finally, the distillate of the adjustment solution 23 after the second distillation was allowed to stand for 4 hours and allowed to spontaneously precipitate and separate due to the difference in specific gravity, and finally purified glycerin 18 and purified fatty acid methyl ester 19 were obtained.

FIG. 4 is a comparison table of Examples 1-4 and Comparative Examples 1-2 for purified fatty acid methyl esters. As shown in the table, the refined fatty acid methyl ester of Example 1 has the density, viscosity, moisture, flash point, residual carbon content, sulfur content, ash content as defined in the American standard ASTM PS121-99 for biodiesel fuel. The standard value of residual methanol etc. is satisfied and can be used as biodiesel fuel oil as it is.
The residual alcohol contained in the purified fatty acid methyl ester 19 was evaluated by gas chromatography, and the other properties were evaluated by the method defined in the JIS standard for light oil.

FIG. 5 is a comparison table of Examples 1 to 4 and Comparative Examples 1 and 2 for purified glycerin. As shown in the table, the quality evaluation of the purified glycerin of Example 1 was performed according to the method defined in the industry standard for purified glycerin.
The purified glycerin of Example 1 satisfies the standard values of glycerin content, color, density, acidity, saponification equivalent, reducing substance test and ignition residue defined in Japanese JIS standard K3351-95 for industrial glycerin. Yes.

FIG. 6 is a comparison table of Examples 1 to 4 and Comparative Examples 1 and 2 in heavy oil substitute fuel. The quality evaluation of the heavy oil substitute fuel of Example 1 was performed by the method defined in the quality standard K 2205 of heavy oil.
The heavy oil substitute fuel of Example 1 is close to the property of C heavy oil as shown in FIG. 3, and can be used as an alternative fuel for C heavy oil.

  In addition, the oil content of the potassium sulfate crystal | crystallization measured by the calcination method is 12%, the water content of the collection | recovery methanol measured by the Karl Fischer method is 3540 ppm, and it is in the collection | recovery water by a gas chromatograph mass spectrometer (GC-MS). The organic matter content was 300 ppm. For this reason, potassium sulfate can be used as an agricultural chemical fertilizer or chemical raw material, and recovered methanol can be reused as a raw material for a transesterification reaction between waste oil and methanol. Further, the recovered water may be discharged into sewage as it is.

[Example 2]
In Example 2, the waste oil and fat 1 as the raw material, the alcohol 2 as the auxiliary raw material, and the alkali catalyst 3 were the same as those in Example 1.
By mixing 4.03 parts by weight of the alkali catalyst with 100 parts by volume of the alcohol 2 and stirring, a mixed solution of the alcohol and the alkali catalyst was prepared.

The treated waste oil 1 was mixed with 40 parts by volume of a mixed solution of the methanol and the alkali catalyst, and this mixed solution was stirred at a temperature of 65 ° C. for 20 minutes to perform a transesterification reaction.
Water was added to the reaction product 10 obtained by the transesterification reaction so that the water concentration became 3%, and the components were adjusted to obtain an adjusted solution 23B.
About this adjustment solution 23B, the subsequent process performed the process similar to Example 1, and obtained the refinement | purification glycerin 18 and the refinement | purification fatty acid methyl ester 19 of Example 2. FIG.

As shown in FIG. 4, the purified fatty acid methyl ester 19 of Example 2 has density, viscosity, moisture, flash point, residual carbon content, sulfur content, ash content as defined in the American standard ASTM PS121-99 for biodiesel fuel. It satisfies the standard value of residual methanol and can be used as it is as biodiesel fuel oil.
As shown in FIG. 5, the purified glycerin 18 of Example 2 has a glycerin content, color, density, acidity, saponification equivalent, reducing substance test and ignition in accordance with Japanese JIS standard K3351-95 for industrial glycerin. Satisfies the remaining standard value.
As shown in FIG. 6, the quality evaluation of the heavy oil alternative fuel of Example 2 was performed by the method defined in the heavy oil quality standard K 2205.
The measured oil content of potassium sulfate crystals was 12%, the measured water content of recovered methanol was 3610 ppm, and the measured organic content in recovered water was 310 ppm. For this reason, potassium sulfate can be used as an agricultural chemical fertilizer or chemical raw material, and recovered methanol can be reused as a raw material for a transesterification reaction between waste oil and methanol. Further, the recovered water may be discharged into sewage as it is.

[Example 3]
In Example 3, the waste oil and fat 1 as a raw material, the alcohol 2 as a secondary raw material, and the alkali catalyst 3 were the same as those in Example 1.
About the pre-processing and transesterification of the waste fat and oil 1, it carried out similarly to the pre-processing and transesterification of the waste fat and oil 1 in Example 1.

About the reaction product 10 obtained by transesterification, it processed in the following order.
First, methanol and water were added to the reaction product 10, and the components were adjusted so that the concentrations of methanol and water would be 12.5% and 0.75%, thereby obtaining an adjusted solution 23B. Next, 98% concentrated sulfuric acid was added dropwise at a constant rate while maintaining the temperature of the adjustment solution 23B at 15 ° C. and stirring the adjustment solution 23B until the final pH of the adjustment solution 23B reached 5.0.

This adjustment solution 23 was suctioned under reduced pressure to determine the quantitative filter paper No. The crystals of potassium sulfate were filtered off by passing through 5C.

  The filtered adjustment solution 23 was distilled under reduced pressure at a pressure of 20 mmHg, and methanol (distillation temperature 43 ° C.) and water (distillation temperature 6.5 ° C.) were distilled.

Furthermore, the adjustment solution 23 after removing the methanol and water by distillation was distilled at a pressure of 5 mmHg to distill a mixture of glycerin and fatty acid methyl ester (distillation temperature 140 ° C. to 200 ° C.).
Distilled residual oil after distilling glycerin and fatty acid methyl ester was recovered as heavy oil substitute fuel 17 from the distillation still as it was.

  Finally, the distillate was allowed to stand for 4 hours and allowed to spontaneously precipitate and separate due to the difference in specific gravity. Finally, purified glycerin 18 and purified fatty acid methyl ester 19 were obtained.

  As shown in FIG. 4, the purified fatty acid methyl ester of Example 3 has density, viscosity, moisture, flash point, residual carbon content, sulfur content, ash content, as defined in the American standard ASTM PS121-99 for biodiesel fuel. The standard value of residual methanol etc. is satisfied and can be used as biodiesel fuel oil as it is.

  As shown in FIG. 5, the purified glycerin 18 of Example 3 has a glycerin content, color, density, acidity, saponification equivalent, reducing substance test and ignition temperature defined in Japanese JIS K3351-95 for industrial glycerin. Satisfies the remaining standard value.

As shown in FIG. 6, the heavy oil alternative fuel 17 of Example 3 is close to the property of C heavy oil as shown in FIG. 3, and can be used as an alternative fuel for C heavy oil.
The measured oil content of potassium sulfate crystals was 12%, the measured water content of recovered methanol was 3440 ppm, and the measured organic content in recovered water was 320 ppm. For this reason, potassium sulfate can be used as an agricultural chemical fertilizer or chemical raw material, and recovered methanol can be reused as a raw material for a transesterification reaction between waste oil and methanol. Further, the recovered water may be discharged into sewage as it is.

[Example 4]
In Example 4, waste oil and fat 1 as a raw material, alcohol 2 as a secondary raw material, and alkali catalyst 3 were the same as those in Example 1.

The mixing / dissolution process for obtaining a mixed solution of alcohol and alkali catalyst is carried out in methanol at a ratio of 4.03 parts by weight of industrial potassium hydroxide (KOH content: 95%) to 100 parts by volume of methanol (purity 99.8%). Prepared by dissolving.
The transesterification reaction between waste oil and methanol was performed at a ratio of 40 parts by volume of the methanol / alkali catalyst mixed solution to 100 parts by volume of the vacuum dehydrated and deoxidized waste oil and fat, and the temperature was 60 ° C. for 20 minutes. This was carried out with stirring.

  In the component preparation step of the reaction product, water was added to the reaction product so that the concentration of water was 3% to obtain a component-adjusted reaction product liquid. Other steps shown in FIG. 2 were performed in the same manner as in Example 3.

As shown in FIG. 4, the purified fatty acid methyl ester of Example 4 has density, viscosity, moisture, flash point, residual carbon content, sulfur content, ash content, as defined in the American standard ASTM PS121-99 for biodiesel fuel. The standard value of residual methanol etc. is satisfied and can be used as biodiesel fuel oil as it is.
As shown in FIG. 5, the purified fatty acid methyl ester of Example 4 has the glycerin content, color, density, acidity, saponification equivalent, reducing substance test and strength specified in Japanese JIS standard K3351-95 for industrial glycerin. The standard value of heat residue is satisfied.
As shown in FIG. 6, the quality evaluation of the heavy oil alternative fuel of Example 2 was performed by the method defined in the heavy oil quality standard K 2205.
The measured oil content of potassium sulfate crystals was 12%, the measured water content of recovered methanol was 3450 ppm, and the measured organic content in recovered water was 320 ppm.

[Comparative Example 1]
In Comparative Example 1, waste oil and fat as a raw material, alcohol as a secondary raw material, and alkaline compound as a catalyst were the same as those in Example 1.
In the processing step of Comparative Example 1, the processing steps substantially the same as those of Example 1 were sequentially executed except that the heavy liquid component adjustment step was not executed.
The oil content of potassium sulfate crystals was 45%, the measured water content of recovered methanol was 3500 ppm, and the measured organic content in recovered water was 410 ppm.

[Comparative Example 2]
In Comparative Example 2, waste oils and fats as raw materials, alcohols as auxiliary raw materials, and alkaline compounds as catalysts were the same as those in Example 1.
In the processing step of Comparative Example 2, the processing steps substantially the same as those of Example 3 were sequentially performed except that the reaction product component adjustment step was not performed.
The measured oil content of potassium sulfate crystal was 48%, the measured water content of recovered methanol was 4100 ppm, and the measured organic content in recovered water was 370 ppm.

  INDUSTRIAL APPLICABILITY The present invention can be used for recycling waste oils and fats that have been discarded in large quantities.

It is a processing block diagram in the 1st chemical recycling method of the waste fats and oils of this invention. It is a processing block diagram in the 2nd chemical recycling method of the waste fats and oils of this invention. 3 is a composition table of heavy liquid of Example 1. It is a comparison table of Examples 1-4 and comparative examples 1-2 in refined fatty acid methyl ester. It is a comparison table of Examples 1-4 and comparative examples 1-2 in refined glycerin. It is a comparison table of Examples 1-4 and comparative examples 1-2 in heavy oil alternative fuel.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fat and oil 2 Alcohol 3 Alkali catalyst 10 Reaction product 11 Water 12 Alcohol 13 Inorganic acid 14 Inorganic salt 15 Water 16 Alcohol 17 Fuel oil alternative fuel 18 Refined glycerol 19 Fatty acid alkyl ester 21 Light liquid 22 Heavy liquid 30 Fatty acid alkyl ester S11 Transesterification S12 Phase separation S21 Component adjustment S22 Acid addition S23 Inorganic salt removal S24 First distillation S25 Second distillation S26 Phase separation

Claims (4)

A method of chemically recycling waste oil and fat,
The waste oil and fat is subjected to a transesterification reaction with a mixture of an alcohol and an alkali catalyst.
The reaction product obtained by the transesterification reaction is phase-separated into a heavy liquid and a light liquid, and the heavy liquid is taken out,
To the heavy liquid, water and alcohol are added to adjust the ingredients,
To the adjustment solution obtained by adjusting the components, an inorganic acid is added so that the pH of the adjustment solution is 3.0 to 7.0,
Removing inorganic salts from the adjustment solution to which the inorganic acid has been added;
Distilling the conditioning solution from which the inorganic salt has been removed to remove water and alcohol;
Distilling the conditioning solution from which the water and alcohol have been removed;
A method for chemical recycling of waste oils and fats, wherein the distillate of the adjustment solution is phase-separated into a second heavy liquid and a second light liquid. A method of chemically recycling waste oil and fat,
The waste oil and fat is subjected to a transesterification reaction with a mixture of an alcohol and an alkali catalyst.
To the reaction product obtained by the transesterification reaction, water and alcohol were added to adjust the components,
To the adjustment solution obtained by adjusting the components, an inorganic acid is added so that the pH of the adjustment solution is 3.0 to 7.0.
Removing inorganic salts from the adjustment solution to which the inorganic acid has been added;
Distilling the conditioning solution from which the inorganic salt has been removed to remove water and alcohol;
Distilling the conditioning solution from which the water and alcohol have been removed;
A method for chemical recycling of waste oil and fats, wherein the distillate of the adjustment solution is phase-separated into a heavy liquid and a light liquid. The method for chemical recycling of waste oil according to claim 1 or 2, wherein the concentration of the component-adjusted adjustment solution is 20 to 80% by weight. The method of chemical recycling waste oil according to claim 1 or 2, wherein the adding step of the inorganic acid is performed at a temperature of 5 to 60 ° C.

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