WO2009002055A1

WO2009002055A1 - Manufacturing method of diesel using waste corn oil

Info

Publication number: WO2009002055A1
Application number: PCT/KR2008/003544
Authority: WO
Inventors: Byong Woo Yoo
Original assignee: Vodustm Co.,Ltd
Priority date: 2007-06-22
Filing date: 2008-06-20
Publication date: 2008-12-31
Also published as: CN101328419A

Abstract

Disclosed is a method of manufacturing diesel fuel by using waste edible oil, wherein the method comprises the steps of: a) removing impurities in the waste edible oil, which is vegetable oil containing fatty acid of 0.01% or less, at 8O0C; b) carrying out a methyl esterification reaction by adding a sodium hydroxide-methanol solution to the waste edible oil of step a); c) neutralizing a reaction solution from step b) by adding a phosphoric acid (H3 PO4 ) solution; d) adding sodium hydroxide to the solution, followed by precipitation, and separating the solution into a first layer (organic layer), a second layer (glycerin-methanol layer), and a third layer (sodium hydroxide- phosphoric acid layer); e) removing the second layer (glycerin-methanol layer) and the third layer (sodium hydroxide-phosphoric acid layer), and recovering the first layer (organic layer); and f) carrying out a water- washing and drying process for the recovered first layer (organic layer). In the method, an expensive device is not required, thereby reducing the manufacture cost. Also, glycerin and waste catalyst can be recycled, thereby preventing the generation of waste water. Also, a separated and recovered by-product (glycerin) can be recycled, and methanol can be reused by recovery, thereby increasing economical efficiency, and reducing en¬ vironmental pollution.

Description

MANUFACTURING METHOD OF DIESEL USING WASTE

CORN OIL

Technical Field

[1] The present invention relates to a method for manufacturing diesel fuel using waste edible oil. Background Art

[2] Recently, as the manufacture of industrial machines and vehicles including diesel engines has rapidly increased worldwide with the development of industry, the consumption of diesel used as their energy source has been increased. As compared to various fuels obtained from crude oil, diesel is inexpensive, and thus is advantageous in the view of cost reduction, but has a problem of generating a large amount of air pollution after its combustion.

[3] The present invention provides a method for manufacturing diesel fuel using waste edible oil (waste corn oil). Through the diesel fuel to be manufactured according to the present invention, it is possible to recycle waste edible oil, and to prevent environmental pollution. Also, the diesel fuel of the present invention can be recycled through the separation of a residual material (glycerin) in a methyl esterification reaction.

Disclosure of Invention Technical Problem

[4] Therefore, the present invention has been made in view of the above-mentioned problems. The present invention provides a method for manufacturing diesel fuel using waste edible oil. Technical Solution

[5] In accordance with an aspect of the present invention, there is provided a method of manufacturing diesel fuel by using waste edible oil, the method including the steps of: a) removing impurities in the waste edible oil, which is vegetable oil containing fatty acid of 0.01% or less, at 8O⁰C; b) carrying out a methyl esterification reaction by adding a sodium hydroxide-methanol solution to the waste edible oil of step a); c) neutralizing a reaction solution from step b) by adding a phosphoric acid (H PO ) solution;

3 4 d) adding sodium hydroxide to the solution, followed by precipitation, and separating the solution into a first layer (organic layer), a second layer (glycerin-methanol layer), and a third layer (sodium hydroxide -phosphoric acid layer); e) removing the second layer (glycerin-methanol layer) and the third layer (sodium hydroxide -phosphoric acid layer), and recovering the first layer (organic layer); and f) carrying out a water- washing and drying process for the recovered first layer (organic layer).

[6] Preferably, examples of the waste edible oil according to the present invention may include plentiful and various fatty oils, such as soybean oil, corn oil, etc., but the present invention is not limited thereto.

[7] Preferably, a gravity sedimentation method of impurity removing methods is relatively economical and may be used without limitations because a separate expensive device is not required. Also, in this method, a filter is simply used to remove impurities such as moisture, oxides, plant residues included within the waste edible oil, etc.

[8] Preferably, a methyl esterification reaction is carried out according to a conventional method known in the art. The methyl esterification reaction is preferably carried out under conditions of 50 to 7O⁰C for 150 to 200 minutes. If the reaction temperature is lower than 5O⁰C, it is difficult to carry out the reaction, and on the other hand, if the reaction temperature is higher than 7O⁰C, the cost for the experiment is increased due to the increase of experimental energy consumption. Also, if the reaction time is less than 150 minutes, the yield is low because there is no complete reaction, and on the other hand, if the reaction time is more than 200 minutes, the production efficiency is reduced. Accordingly, in the process of the reaction, when a kneading machine is used to carry out a kneading process, it is possible to reduce the reaction time and to significantly increase the reaction yield.

[9] Preferably, sodium hydroxide is used as catalyst, and the amount of the sodium hydroxide used in the present invention varies depending on the pH value of the waste edible oil. As the catalyst, the sodium hydroxide may be usually substituted by potassium hydroxide (KOH) or sodium carbonate (NaCO ). However, in the case of using such substitutes, the disposal of residual materials is difficult, thereby causing environmental pollution. Also, in the case of the potassium hydroxide (KOH), when the content reaches 1.4 times (on a molecular weight basis) of sodium hydroxide, the production cost increases. Therefore, it is the most ideal to use sodium hydroxide.

[10] Preferably, in measuring a pH value of waste edible oil in the present invention, a conventional method by using a pH reagent, pH test paper, a pH meter, etc. is used, but the present invention is not limited thereto. For example, in the case of using phe- nolphthalein as indicator, Ig of sodium hydroxide is dissolved in IL of distilled water (pure water) to obtain 0.1% sodium hydroxide aqueous solution. 10ml of IPA is fed in a small sized glass cup, dehydration is prepared, and then ImI of edible oil is dissolved therein. During the dissolution, the glass is subjected to vibration so that the edible oil can be completely dissolved. Herein, a small amount of phenolphthalein is added to the dissolved oil, and the pH value of the edible oil is measured by adding the sodium hydroxide aqueous solution so as to quantitatively determine an amount of the sodium hydroxide.

[11] The pH meter includes a pH measuring electrode, a reference electrode, and a high input impedance amplifier. The pH electrode changes depending on pH values of measured solutions, and outputs an electromotive force value (mV) according to a change in pH of inside/outside of a hydrogen ion sensitive glass bulb thereof. In the measurement, a glass tube is filled with a solution B whose internal pH value is known, and the tube is immersed in a test sample solution A to measure electrodes of both sides of a glass membrane. Herein, appropriate electrodes El and E2 are fed into both solutions A and B, and a potential difference between the two electrodes is measured so as to measure an electromotive force generated on the glass membrane. If the potential value of the glass membrane changes according to the change in concentration of hydrogen ions, it is possible to measure the pH value of the corresponding solution through the potential difference between the two electrodes. Additionally, the following matters require attention in the pH measurement. The measurements of the pH electrode and temperature are very sensitive, and thus a temperature compensation means provided in the pH meter is used to manually or automatically carry out temperature compensation. In manual compensation, the temperature compensation is separately carried out so as to manually adjust appropriate temperature of a pH meter. Meanwhile, automatic compensation is accomplished through a separate temperature probe. The temperature probe sends a pH signal to a pH meter, and produces a temperature-compensated pH reading of a solution having a temperature lower than a predetermined temperature. In electrical circuit related to the pH meter, an electrode reaction is represented by the Nernst equation (mathematical formula). On the basis of the equation, under the temperature condition of 25⁰C, an electromotive force of 59.16mV may be obtained. In other words, as the pH value of a glass pH electrode within a solution changes, a pH meter outputs the electromotive force value (mV) scaled for temperature in accordance with the Nernst equation. For example, at 505⁰C, the electromotive force of 64.1 mV per pH may be obtained.

[12] Preferably, during the drying process, the reaction is carried out at 55 to 65⁰C for 15 to 25 minutes after void spaces are filled up, but the present invention is not limited thereto.

[13] In a neutralization reaction, when the concentration of a phosphoric acid solution is relatively high, it is difficult to determine the injection amount, and to carry out the neutralization reaction. Therefore, it is the most preferable to use a concentration of about 10%.

Advantageous Effects [14] According to the method of manufacturing diesel fuel using waste edible oil in the present invention, it is possible to remove impurities within the edible oil through gravity sedimentation, and to simply separate residual materials, such as glycerin and waste additives, by gravity difference. Also, an expensive device is not required, thereby reducing the manufacture cost. Also, glycerin and waste catalyst can be recycled, thereby preventing the generation of waste water. [15] Also, a separated and recovered by-product (glycerin) can be recycled, and methanol can be reused by recovery, thereby increasing economical efficiency, and reducing environmental pollution.

Brief Description of the Drawings [16] The foregoing and other objects, features and advantages of the present invention will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which: [17] FIG. 1 illustrates a process of obtaining ester from waste edible oil and organic catalyst; [18] FIG. 2 illustrates a process of manufacturing diesel fuel according to the present invention; [19] FIG. 3 illustrates a step of recovering methanol in the diesel fuel manufacturing process according to the present invention; [20] FIG. 4 illustrates the production yield of diesel fuel according to the amount of

NaOH catalyst (reaction conditions: 65⁰C, 150 minutes, 1 wt% of NaOH); [21] FIG. 5 illustrates the production yield of diesel fuel according to the amount of methanol (reaction conditions: 65⁰C, 150 minutes, 80wt% of methanol); [22] FIG. 6 illustrates the production yield of diesel fuel according to reaction time

(reaction conditions: 65⁰C, 150 minutes, 80wt% of methanol, lwt% of NaOH); and [23] FIG. 7 illustrates the reaction pressure and production yield of diesel fuel according to reaction time (reaction conditions: 65⁰C, 150 minutes, 80wt% of methanol, lwt% of

NaOH).

Mode for the Invention [24] Reference will now be made in detail to the preferred embodiments of the present invention. However, the following examples are illustrative only, and the scope of the present invention is not limited thereto. [25] Example

[26] Example 1: Manufacture of diesel fuel by using waste edible oil

[27] Edible oil (vegetable oil, fatty acid of 0.01% or less) commercially available from

Cheil Jedang, and methanol (99% or more) commercially from Methani were used as test materials, and NaOH (95% or more) commercially from Nidek was used as catalyst.

[28] First, a gravity sedimentation method of impurity removing methods was carried out for a certain time at room temperature to remove the impurities, such as moisture, oxides, plant residues, etc. included within waste edible oil, and some materials blocking a methyl esterification reaction.

[29] After removing the impurities included in the waste edible oil, a sodium hydroxide

(NaOH)-methanol (CH OH) solution was added thereto, to carry out a methyl esterification reaction. Through the reaction, fatty acid of triglyceride (one of main components of the waste edible oil) was separated and a chemical reaction between a methyl group and fatty acid was performed to obtain methyl ester. Herein, since the waste edible oil was changed into methyl ester, the molecular weight was lowered to one third, the viscosity was lowered to one tenth, and also the boiling point and flashing point were significantly lowered, as compared to its original values. The methyl esterification reaction was carried out at 50 to 7O⁰C for 150 to 200 minutes.

[30] After the methyl esterification reaction, in the methyl esterification reaction solution, a neutralizing agent (a phosphoric acid (H PO ) solution) was added, and sodium hydroxide was added thereto. Then, saponified methyl ester was used as a source for an organic layer, and the catalyst (sodium hydroxide) was precipitated.

[31] Then, through the difference in specific gravity, the organic layer (top layer), a glycerin-methanol layer (middle layer), a sodium hydroxide-phosphoric acid layer (bottom layer) were formed. Herein, the layer separation was carried out in such a manner that the top layer (organic layer of methyl ester) has a specific gravity of 0.89, the glycerin-methanol layer has a specific gravity of about 1.2, and the sodium hydroxide-phosphoric acid layer has a specific gravity higher than those of the top and middle layers.

[32] From the solution whose layers were separated, the glycerin-methanol layer and the sodium hydroxide-phosphoric acid layer were removed. Then, only the methyl ester organic layer was recovered and was subjected to a water-washing and drying process to obtain high quality diesel fuel according to the present invention.

[33] In the water-washing process, soluble materials remaining in the organic layer are dissolved in water. If the fuel is required to be cleaned, a bubble washing process is carried out. Also, the drying process for removing residual materials, such as residual moisture or unseparated methanol, etc., is carried out at 55 to 65⁰C for 15 to 25 minutes after void spaces are filled.

[34] Example 2: Manufacture of fuel by recovering methanol

[35] In the step of removing a glycerin-methanol layer and a sodium hydroxide- phosphoric acid layer as described in Example 1, from a solution including the glycerin-methanol layer and the sodium hydroxide-phosphoric acid layer, the sodium hydroxide-phosphoric acid layer was filtered out and removed. Then, the glycerin- methanol layer was distilled and filtered, and methanol was independently recovered to obtain redundant glycerin. Herein, the recovered methanol was used for the methyl es- terification reaction, thereby lowering manufacture cost. Also, glycerin can be re-used as a cosmetic material through recovery, thereby achieving the recycle use of resources.

[36] Example 3: Performance Test

[37] 150ml of diesel fuel which was not passed through a water- washing step and a drying step was collected and fed into a 500ml vessel, and then 150ml of water was added thereto, followed by sufficiently stirring for 10 seconds. Then, the mixture was left for 30 minutes. Herein, if the mixture is separated into diesel fuel (top layer) and a milk- colored aqueous layer (bottom layer), the fuel has high quality. On the other hand, if the left mixture is in a fluid state or is not clearly separated, the fuel is not accepted. Thus the test should be conducted again from the start. Industrial Applicability

[38] Although several exemplary embodiments of the present invention have been described for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

[1] A method of manufacturing diesel fuel by using waste edible oil, wherein the method comprises the steps of: a) removing impurities in the waste edible oil, which is vegetable oil containing fatty acid of 0.01% or less, at 8O⁰C; b) carrying out a methyl esterification reaction by adding a sodium hydroxide- methanol solution to the waste edible oil of step a); c) neutralizing a reaction solution from step b) by adding a phosphoric acid (H PO 4 ) solution; d) adding sodium hydroxide to the solution, followed by precipitation, and separating the solution into a first layer (organic layer), a second layer (glycerin-methanol layer), and a third layer (sodium hydroxide-phosphoric acid layer); e) removing the second layer (glycerin-methanol layer) and the third layer (sodium hydroxide-phosphoric acid layer), and recovering the first layer (organic layer); and f) carrying out a water-washing and drying process for the recovered first layer (organic layer).

[2] The method as claimed in claim 1, wherein the methyl esterification reaction in step b) is carried out at 50 to 7O⁰C, for 150 to 200 minutes.

[3] The method as claimed in claim 1, wherein the drying process in step f) is carried out at 55 to 65⁰C, for 15 to 25 minutes.

[4] Diesel fuel using waste edible oil, which is manufactured by the method as claimed in claim 1.