KR101099367B1 - Method for simultaneous refining of crude bio-diesel and crude glycerin in bio-diesel production process - Google Patents

Abstract

PURPOSE: A refining method of crude biodiesel and crude glycerine obtained from a biodiesel producing process at the same time is provided to obtain high purity glycerine and biodiesel without the discharge of intermediate effluent. CONSTITUTION: A refining method of crude biodiesel and crude glycerine obtained from a biodiesel producing process at the same time comprises the following steps; separating alcohol from an esterification reaction outcome of oil and the alcohol, and separating the crude biodiesel and the crude glycerine; mixing the crude glycerine with intermediate effluent, and hydrolyzing tri, di, and mono glycerides from the crude glycerine into glycerine and fatty acid; separating the fatty acid, and evaporating and condensing the moisture from remaining outcome to obtain condensed water; and washing the crude biodiesel with the condensed water before separating into refined biodiesel and the intermediate effluent containing impurities.

Description

Method for simultaneous refining of crude bio-diesel and crude glycerin in bio-diesel production process

The present invention relates to a method for purifying crude glycerin using intermediate water (waste water) generated in the washing process of crude biodiesel as a product in a process for producing biodiesel by esterification of fats and oils and alcohols.

Various alternative energy has been proposed to solve the problem of global depletion of fossil energy and environmental pollution caused by the use of fossil energy. In particular, biodiesel has been diversified as alternative fuels that can be used in existing fossil-energy devices. have. Biodiesel is an esterified oil produced by the reaction of an oily or renewable waste food such as vegetable oil, animal fat, with an alcohol in the presence of an acid catalyst or an alkali catalyst. Biodiesel has similar properties to diesel fuel used in vehicle fuels, so it can be mixed and compressed with diesel fuel or used in diesel engines as a substitute for diesel fuel. Accordingly, various biodiesel production methods have been proposed.

On the other hand, in the conventional biodiesel manufacturing process, it is common to further refine the produced crude biodiesel by washing (washing) and then further evaporation / distillation. That is, according to the prior art, water is added to the crude biodiesel produced by transesterification and primary separation, and the impurities such as glycerin, fatty acid salt and catalyst remaining in the crude biodiesel are washed and washed. According to this prior art, a large amount of intermediate water (wastewater) discharge is inevitable in the process of purifying biodiesel, causing pollution problems and rising water treatment costs.

The present invention for solving the above problems of the prior art, by using the intermediate water (wastewater) generated in the purification (washing) step of biodiesel during the biodiesel manufacturing process in the glycerin separation purification process, or no waste water is generated It aims to provide a new purification method that can solve almost no water pollution problem or water treatment cost problem.

The present invention for achieving the above object is the step of (A) separating the alcohol from the esterification result of the oil and alcohol and the crude (glycer) and crude biodiesel (crude); (B1) mixing the crude glycerin separated in step (A) with the following intermediate water and then converting the tri-, di- and mono-glycerides remaining in the crude glycerin into glycerin and fatty acid; (B2) separating the fatty acid produced in step (B1) and evaporating and condensing water in the residue to obtain condensed water; And (C) washing the crude biodiesel separated in step (A) with condensed water obtained in step (B2) and separating the bio-diesel containing water and the intermediate water (waste water) containing impurities. The present invention relates to a method for simultaneously purifying crude glycerin and crude biodiesel produced by a biodiesel manufacturing process.

Biodiesel containing moisture generated in the step (C) is subjected to dehydration process and finally commercialized.

In the present invention, if necessary, after distilling the crude glycerin remaining after the step (B2) to separate the purified glycerin and the pitch, or after the step (C) through the dehydration process to distill the biodiesel and purified again It is also possible to add.

A conceptual flowchart of a biodiesel manufacturing process by a method of simultaneously purifying crude glycerin and crude biodiesel according to the present invention is shown in FIG. 1.

The intermediate water mixed with the crude glycerin in the step (B1) of the present invention is 20 to 50 (v / v)% in the total mixture, preferably 40 (v / v)%. If the intermediate number is less than 10 (v / v)%, the hydrolysis effect is insignificant. If it is more than 50 (v / v)%, the energy consumption is greatly increased.

In the step (C) of the present invention, the condensate mixed with the crude biodiesel is preferably 5 to 15 (v / v)%, more preferably 10 (v / v)% in the total mixture. If the condensate is less than 5 (v / v)%, the water washing effect is insignificant. If it is more than 15 (v / v)%, waste water generation is increased.

Therefore, in the step (B1) or step (C) of the present invention, it is preferable to add water to the intermediate water or condensate if necessary, or to reduce the mixing amount of the intermediate water or condensate.

At this time, citric acid may be added to the condensate to increase the washing efficiency. The added citric acid reacts with the sodium component used as the biodiesel catalyst to form sodium citrate. Sodium citrate is a substance used as an emulsifying stabilizer to increase the washing efficiency by inducing impurities to be completely dissolved in water in the biodiesel washing process.

Biodiesel is generally transesterified methanol and fats and oils (raw oil) by the addition of a catalyst in a continuous reactor, separated and discharged by-product glycerin in the separator, separated from the biodiesel separated from glycerin by washing with distilled water, It is manufactured through a dehydration distillation process. Soybean oil, corn oil, rapeseed oil, linseed oil, sunflower oil, poppy oil, walnut oil, peanuts, cottonseed oil, rice bran oil, camellia oil, castor oil, olive oil, tallow, lard ), Fish oil (경), light oil (鯨 油), waste cooking oil may be any one or a mixture selected.

The present invention relates to a method for producing high-purity glycerin and biodiesel by purifying crude glycerin using intermediate water (wastewater) generated in the washing step of crude biodiesel in a method for purifying crude glycerin. Hereinafter, the present invention will be described in detail.

First, a transesterification reaction is carried out using fats and oils and methanol according to a conventional method, and crude glycerin and crude biodiesel are separated using a predetermined separator. For reference, the weight ratio of the separated crude glycerin and crude biodiesel was about 1:10.

Subsequently, the separated crude glycerin and intermediate water are added to the primary reactor 101 to perform a hydrolysis reaction at 90 to 120 ° C. After completion of the reaction the reactant is transferred to the secondary reactor 102 and acid treated to pH 2-5. After the reaction is transferred to the decanta 103, the fatty acid in the upper layer is transferred to the reservoir and the crude glycerin in the lower layer is transferred to the tertiary reactor 104. Subsequently, a base (eg, NaOH) is added to crude glycerin of the tertiary reactor 104 to neutralize to pH 6-8, water is removed from the evaporator 105, and distilled from the distillator 107 to prepare purified glycerin .

Meanwhile, the condensed water condensed in the evaporator 105 is sent to the mixer 201 through the condenser 106 recovery tank and mixed vigorously with the crude biodiesel from which methanol and glycerin are removed. The mixture is then separated by centrifuge 202 to obtain purified biodiesel from which impurities are removed to the top. The biodiesel may be further subjected to distillation. Intermediate water (wastewater) discharged to the bottom of the centrifuge 202 is sent to the primary reactor 101 is reused continuously.

As described above, according to the present invention, biodiesel is produced without intermediate water discharge by purifying glycerin using intermediate water generated in the washing process of crude biodiesel, and the impurities contained in the intermediate water can be reused in the glycerin purification process. do. Therefore, by improving the recovery rate of glycerin and minimizing the amount of water used, it is possible to improve the environment and reduce the manufacturing cost.

1 is a conceptual flowchart of a biodiesel manufacturing process to which the purification method according to the present invention is applied.
Figure 2 is a conceptual diagram showing each device and their relationship in the example of the manufacturing process of the biodiesel to which the purification method according to the present invention is applied.

Hereinafter, the present invention will be described in more detail with reference to the accompanying drawings and embodiments. However, these drawings and embodiments are only examples for easily explaining the contents and scope of the technical idea of the present invention, and thus the technical scope of the present invention is not limited or changed. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the technical idea of the present invention based on these examples.

Example

The mixture of animal and vegetable fats and oils (1 mol = 880 g) and methanol (6 mol = 190.6 g) was mixed at a molar ratio of 1: 6. The usual transesterification reaction was carried out for a time. Subsequently, crude glycerin and crude biodiesel were separated using a predetermined separator.

Examples 1-3: Purification of crude glycerin using intermediate water (washing)

Inject 100 g of the separated crude glycerin and 92 g of the intermediate water generated in the biodiesel washing process (described later), and then raise the temperature of the reactor to 110 ° C. while stirring to maintain unreacted reaction in glycerin for 1 hour (mono-, di-, Or tri-glycerides) to hydrolyze to form glycerin and fatty acid sodium salts.

Wherein each R may be the same or different aliphatic chain between C14 to C24, typically found in animal or vegetable fats or oils.

This is injected into a secondary reactor (volume: 500 ml), and then 6.3 g of hydrochloric acid (30% sol'n.) Is mixed to pH 2-5. It is preferable to add hydrochloric acid 0.3-2.0% with respect to the crude glycerin weight.

The mixture was precipitated in decanta, and the mixture of glycerin and NaCl precipitated in the lower layer was introduced into a tertiary reactor (volume: 500 ml), mixed with 1.0 g of NaOH (50% sol'l.), And neutralized to pH 7-8. It was dehydrated in an evaporator to remove water and reused this water (condensed water) in the washing process of biodiesel to make biodiesel without generation of intermediate water (waste water). Finally, the glycerin from which water is removed from the evaporator is distilled in a distillation to produce high purity glycerin.

The yield of the product thus prepared is shown in Table 1 below.

Examples 4 to 6: Purification of crude biodiesel using condensed water (washing)

The separated crude biodiesel (100 g) and condensed water (5 g) recovered in the glycerin dehydration process of Examples 1 to 3 were mixed and added to a mixer, followed by washing for 5 minutes while vigorously mixing at 80 to 90 ° C. The mixture was then separated by centrifuge (4600 RPM or higher). The separated biodiesel is dehydrated and distilled to become the final product biodiesel. The separated intermediate water (waste water) is reused again in the glycerin purification process of Examples 1-3.

The yield of the product thus prepared is shown in Table 2 below.

As can be seen in the above embodiment, the condensed water produced during the glycerin purification process is again used for washing the crude biodiesel, and the intermediate process (waste water) generated in the washing process of the crude biodiesel is utilized for the glycerin purification. By using this method, high purity glycerin and biodiesel can be obtained with minimal wastewater.

While various features of the invention have been shown and described in detail in connection with the illustrative embodiments of the invention, these specific devices, their methods of manufacture, are by way of example only and are intended to be illustrative only and the invention is within the scope of the claims. It will be understood as fully interpreted in.

(101) Primary Reactor (102) Secondary Reactor (103) Decanta
(104) Tertiary Reactor (105) Evaporator (106) Condenser
(107) Distillers (108) Recovery Tanks (201) Mixers
(202) centrifuge

Claims (5)

(A) separating the crude glycerin and the crude biodiesel after separating the alcohol from the esterification result of the fat and oil and alcohol;
(B1) after mixing the crude glycerin separated in step (A) and the following intermediate water, tri- (tri-), di- (di-) and mono- (mono-) glycerides remaining in the crude glycerin Decomposing and converting to glycerin and fatty acid;
(B2) separating the fatty acid produced in step (B1) and then evaporating and condensing water in the residue to obtain condensed water;
(C) washing the crude biodiesel separated in step (A) with condensed water obtained in step (B2) and then separating the purified biodiesel with intermediate water containing impurities;
Method for simultaneously purifying crude glycerin and crude biodiesel produced by the biodiesel manufacturing process comprising a.
The method of claim 1,
Distilling and refining the crude glycerin remaining after the step (B2) or after the step (C) is produced by the biodiesel manufacturing process comprising the step of distilling the purified biodiesel again. To simultaneously purify crude glycerin and crude biodiesel.
The method of claim 1,
The intermediate water mixed with the crude glycerin in the step (B1) is a method for simultaneously purifying crude glycerin and crude biodiesel produced by the biodiesel manufacturing process, characterized in that 20 to 50 (v / v)% of the total mixture. .
The method of claim 1,
Condensed water mixed with the crude biodiesel in step (C) is a method for simultaneously purifying crude glycerin and crude biodiesel produced by the biodiesel manufacturing process, characterized in that 5 ~ 15 (v / v)% of the total mixture. .
The method according to any one of claims 1 to 4,
Adding water to the intermediate water or condensate, or a method for simultaneously purifying crude glycerin and crude biodiesel produced by the biodiesel manufacturing process, characterized in that for reducing the mixing amount of the intermediate or condensate.

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