KR101328115B1 - Method of improving low temperature property of biodiesel from vegetable oils and animal fats - Google Patents

Abstract

The present invention relates to a method for improving the low temperature fluidity of animal and vegetable oil-derived biodiesel, and more particularly, by adding urea to animal oil-derived biodiesel to reduce the saturated fatty acid methyl ester content. A method for improving and a method for improving the low temperature fluidity of vegetable oil derived biodiesel by mixing biodiesel derived from vegetable oil or fat with reduced saturated fatty acid methyl ester content. According to the present invention, it is possible to obtain biodiesel that can be applied as fuel oil under domestic environmental conditions by improving the low temperature characteristics of biodiesel derived from animal and vegetable fats and oils, and animal biodiesel is manufactured by using livestock by-products. It is expected to be able.

Description

Method of improving low temperature property of biodiesel from vegetable oils and animal fats}

The present invention provides a method for improving the low temperature filter clogging point of animal biodiesel by reducing saturated fatty acid methyl esters in animal biodiesel, and mixing them with biodiesel derived from vegetable fats and oils to prevent cold oil clogging of vegetable fats. It is about how to improve the point.

The global industrialization accelerated since the 20th century is attributed to petroleum resources. Petroleum is not only used as fuel for automobiles, aircraft, thermal power generation, but also widely used as raw materials for various heating oils and synthetic resins. As such, it is reported that oil is an indispensable resource in the modern industrial society, and in recent years, the demand for oil is also increasing as the economic development of emerging developing countries such as China and India has progressed. However, since oil is a non-renewable resource and its reserves are limited, the possibility of resource exhaustion has always been raised. Research on energy sources is being actively conducted.

One of the biomass energy sources that can replace petroleum is biodiesel. Biodiesel is usually prepared through a transesterification method in which glycerol is separated from triglycerides in which glycerol is bound to trivalent fatty acids using methanol, and then produced fatty acid esters. In other words, biodiesel is a mixture of fatty acid methyl ester (FAME), and has similar properties as diesel extracted from petroleum, but significantly lower emissions of aromatics, environmental pollutants, and above all, has the advantage of being a renewable energy source. However, biodiesel has low low temperature fluidity and thus easily aggregates at low temperature, which causes a problem of clogging of the fuel filter when applied as a vehicle fuel.

The low cryogenicity of biodiesel is related to the content of saturated fatty acid methyl esters and unsaturated fatty acid methyl esters. That is, biodiesel having a high content of saturated fatty acid methyl ester and a low content of unsaturated fatty acid methyl ester has poor physical properties due to its high cold flow plug point (CFPP). In particular, biodiesel derived from animal fats and oils (hereinafter referred to as 'animal biodiesel') has a higher content of saturated fatty acid methyl ester than the vegetable fats derived from biodiesel (hereinafter referred to as 'vegetable biodiesel'). This is due to the proportion of saturated fatty acids contained. In general, pork fat and tallow have a saturated fatty acid ratio of 36% and 50%, respectively. Therefore, in order to apply biodiesel, especially animal biodiesel as a fuel for automobiles, it is important to lower the content of saturated fatty acid methyl ester.

In order to improve the low temperature fluidity of biodiesel, Korean Patent Publication No. 10-2005-0058225 and Korean Patent Registration No. 10-0914139 propose techniques for mixing low temperature fluidity improving additives, and some commercialized additives are also commercially available. have. However, these additives can lower the CFPP of the plant biodiesel by about 5 ° C., but there is a problem in that the animal biodiesel derived from the tallow or larch does not show any effect. Korean Patent Registration No. 10-0782130 suggests the effect of lowering the CFPP of the mixture by mixing two different plant biodiesel with CFPP, but an example of applying the animal biodiesel has not been proposed yet.

Accordingly, the present inventors have conducted studies to improve the low temperature fluidity of animal biodiesel, and by adding urea to animal biodiesel to remove saturated fatty acid methyl ester in the form of sediment, the content of saturated fatty acid methyl ester can be reduced. It has been found that the low temperature filter clogging point of animal biodiesel can be significantly lowered, and that the low temperature filter clogging point of vegetable biodiesel can be significantly lowered by mixing animal biodiesel with reduced saturated fatty acid methyl ester content with vegetable biodiesel. The present invention has been completed. Accordingly, an object of the present invention is to provide a method for improving physical properties of animal and vegetable biodiesel applicable to fuel oil.

The present invention

Adding urea to the animal fat derived biodiesel;

Aggregating saturated fatty acid methyl ester and urea contained in animal fat-derived biodiesel to form a clathrate compound; And

Removing the inclusion compound

Characterized in that the low-temperature fluidity improvement method of animal oil-derived biodiesel comprising a.

In addition,

Reducing the content of saturated fatty acid methyl ester by adding urea to the animal fat derived biodiesel; And

Mixing the vegetable oil derived biodiesel with the animal fat derived biodiesel having a reduced content of saturated fatty acid methyl ester;

Characterized by the method for improving the low temperature fluidity of the vegetable oil-derived biodiesel comprising a.

If animal biodiesel is produced using about 50% of domestically produced animal fats and oils, it is estimated that about 183,000 kL of biodiesel can be produced. According to the method for improving the low temperature fluidity of the animal biodiesel of the present invention, it is possible to use the animal biodiesel as fuel oil stably under domestic environmental conditions by greatly improving the low temperature characteristics of the animal biodiesel, and the animal biodiesel is manufactured by using livestock by-products. Therefore, it is expected to contribute to the income increase of livestock farmers.

1 is a photograph of the precipitated saturated fatty acid methyl ester observed 24 hours after adding urea to Uji-derived biodiesel.
Figure 2 shows the results of gas chromatography analysis of Uji-derived biodiesel before adding urea.
FIG. 3 shows the results of gas chromatography analysis after purification of a liquid portion (saturated biodiesel) obtained by adding urea 1: 1 to Uji-derived biodiesel.
Figure 4 shows the result of gas chromatography analysis after purification of the liquid portion (saturated biodiesel) obtained by adding urea 1: 1.5 to fractionated Uji-derived biodiesel.
5 is a result of gas chromatography analysis after purification of a liquid portion (saturated biodiesel) obtained by adding urea 1: 2 to Uji-derived biodiesel and then fractionating it.

Hereinafter, the present invention will be described in more detail.

The present invention relates to a method for improving the low temperature fluidity of animal biodiesel by adding urea to animal biodiesel to remove saturated fatty acid methyl esters.

The animal biodiesel may be derived from animal fat or oil, tallow, lard or a mixture thereof, but is not limited thereto. These animal fats and oils have a very high saturated fatty acid ratio compared to vegetable oils (50% tallow, 36% lard), and thus have a high content of saturated fatty acid methyl esters in animal biodiesel. The disadvantage is poor. Accordingly, the present invention performs the process of reducing the saturated fatty acid methyl ester content by adding urea to animal biodiesel.

When urea is added to animal biodiesel, a white precipitate is formed as shown in FIG. 1, which is an inclusion compound (urea inclusion complexes with saturated fatty acid) formed by aggregation of urea and a saturated fatty acid methyl ester. Therefore, when the precipitate is removed through filtration, animal biodiesel having a high content of unsaturated fatty acid methyl ester can be recovered. It is preferable that the weight ratio of animal biodiesel and urea is 1: 0.5 to 3.If the weight ratio is less than 1: 0.5, the amount of remaining saturated fatty acid methyl ester may be too high to be applied as fuel oil. Even if excess amount of urea is added, the removal effect of saturated fatty acid methyl ester is not large.

The present invention also relates to a method for improving the low temperature fluidity of vegetable biodiesel by mixing animal biodiesel with reduced content of saturated fatty acid methyl ester with vegetable biodiesel as described above.

Vegetable biodiesel has a lower content of saturated fatty acid methyl ester than animal biodiesel. Especially, rapeseed oil-derived biodiesel and camellia-derived biodiesel have a high content of oleic acid and thus have a low cold filter plug point of about -12 ° C. However, the low temperature filter plugging point of vegetable biodiesel derived from waste cooking oil or soybean oil shows properties that are difficult to use as fuel oil at about -4 to -5 ° C.

Animal biodiesel with reduced saturated fatty acid methyl esters is characterized in that most saturated fatty acid methyl esters (particularly palmitic acid and stearic acid) are removed, resulting in relatively high levels of unsaturated fatty acid methyl esters (particularly oleic acid). Therefore, when animal biodiesel having relatively increased content of unsaturated fatty acid methyl ester is mixed with vegetable biodiesel, the unsaturated fatty acid methyl ester content of the mixed biodiesel is higher than the unsaturated fatty acid methyl ester content of the vegetable biodiesel. The effect of further lowering the CFPP can be obtained.

In order to reduce the saturated fatty acid methyl ester content, urea may be added to the mixed oil of animal biodiesel and vegetable biodiesel. However, since vegetable biodiesel has relatively low content of saturated fatty acid methyl ester, There may be problems with increased input or longer settling times. Therefore, when considering the effect of reducing the saturated fatty acid methyl ester relative to the amount of urea, it is preferable to reduce the saturated fatty acid methyl ester using urea before mixing the animal biodiesel with the vegetable biodiesel.

The biodiesel derived from vegetable oils and fats used in the present invention may be derived from at least one selected from rapeseed oil, camellia oil, soybean oil, and waste cooking oil, but is not limited thereto. In addition, the mixing ratio of animal biodiesel and vegetable biodiesel having a reduced content of saturated fatty acid methyl ester is not particularly limited, but is preferably mixed in a volume ratio of 1: 0.25 to 4.

According to the method for improving the low temperature fluidity of the animal and vegetable biodiesel of the present invention, the low temperature filter plugging point of the animal biodiesel can be lowered to a maximum of -15 ° C and the low temperature filter plugging point of the vegetable biodiesel to a maximum of -10 to -18 ° C. Under domestic environmental conditions, animal and plant biodiesel can be used stably as fuel oil.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by the following Examples.

[Example]

Preparation Example 1 Preparation of Uji-derived Biodiesel

The upper layer (oil layer) obtained after grinding the tallow into a blender and hydrothermally treated at 100 ° C. was obtained by passing through anhydrous sodium sulfate. After taking the molar ratio (30 g: 16.7 g, Uji: methanol) of the Uji and methanol in a ratio of 1: 15, 3 g of KOH (1% of the Uji, w / w) was added and reacted at 65 DEG C for 30 minutes. Biodiesel was obtained. The saturated fatty acid content of the Uji-derived biodiesel obtained at this time was 36.92%.

Example  1-3

Methanol (10 mL) and urea were completely dissolved in the Uji-derived biodiesel (2 g), and then left at 10 ° C. for 24 hours. The mixing weight ratio of animal biodiesel and urea is shown in Table 1 below.

division Animal Biodiesel Animal Biodiesel: Urea
(Weight ratio) Example 1 Uji-derived biodiesel 1: 1 Example 2 1: 1.5 Example 3 1: 2

Next, the precipitate was separated using a vacuum filter, and then the obtained liquid phase was transferred to a separatory funnel and 1% hydrochloric acid was added until the pH was 2 to 3 (4 mL). 10 mL of hexane and 5 mL of diethyl ether were added to extract the fatty acid methyl ester. After separating the layers, the upper layer (hexane and diethyl ether layer) was taken, washed with distilled water several times (until the upper layer became clear), and water and impurities were removed using an anhydrous sodium sulfate column. Next, the solvent was completely removed using a rotary vacuum evaporator (EYELA, n-1000, Japan) and nitrogen, and then the yield of unsaturated fatty acid methyl ester with reduced saturated fatty acid was calculated.

The result of gas chromatography analysis before fractionation of the Uji-derived biodiesel into urea is shown in FIG. 2. After the addition of urea to the Uji-derived biodiesel for 24 hours, the liquid portion obtained by removing the precipitate was purified. After the analysis by gas chromatography is shown in Figures 3 to 5.

2 to 5, the peaks of saturated fatty acid myristic acid (myristic acid, C14: 0), palmitic acid (palmitic acid (C16: 0)) and stearic acid (stearic acid, C18: 0) are added As the content of urea increases, it gradually decreases, and it can be seen that the saturated fatty acid methyl ester can be effectively reduced by adding urea.

On the other hand, the weight ratio of the animal biodiesel and urea (1: 1 to 2) and the recovery rate of the fraction (%) according to the standing time and the content of the fatty acid methyl ester are shown in Table 2 below. In Uji, 36.92% of saturated methyl ester was contained, but the recovery ratio of the obtained fraction was 62.17 to 60.14% in weight ratio 1: 1 (Example 1), and the unsaturated methyl ester contained 82.09 to 76.67%. In the weight ratio 1: 1.5 (Example 2), the recoveries of the obtained fractions were 38.25 to 45.59%, of which the unsaturated methyl esters contained 85.41 to 88.60%. In addition, in the weight ratio 1: 2 (Example 3), the yield of the obtained fraction was 26.34 to 32.07%, and the content of unsaturated methyl ester was 93.25 to 96.62%. As the content of urea increases among these, the recovery rate of the obtained fatty acid methyl ester is lowered. And while the content of unsaturated methyl ester is high, the content of saturated methyl ester is low.

division Fatty acid methyl ester (FAME) composition (% by weight) saturation Unsaturation Recovery rate (%) Uji 36.92 63.08 - Example 1 23.33 76.67 60.14 (1.20 g / 2 g) Example 2 11.47 88.53 38.25 (0.76 g / 2 g) Example 3 3.38 96.62 26.34 (0.53 g / 2 g) Saturated methyl ester: 14: 0-myristic acid, 16: 0-palmitic acid, 18: 0-stearic acid
Unsaturated methyl ester: 14: 1-myristoleic acid, 16: 1-palmitoleic acid, 18: 1-oleic acid, 18: 2-linoleic acid, 18: 3-linolenic acid, 20: 1-gadoleic acid
Recovery rate (%): Yield (%) of unsaturated methyl ester obtained by purification after urea fractionation for 2 g of Uji biodiesel

Preparation Examples 2 to 5: Preparation of Biodiesel

In order to prepare biodiesel derived from rapeseed oil, waste cooking oil (Amazon Hoff, Muan), soybean oil (Dong-A Hi-Tech Co., Gwangju), and camellia oil (Dong-A Hi-Tek Co., Gwangju), 160 mL of methanol and 8 g of KOH were added to 830 mL of each oil. After 1 hour of reaction at 65 ~ 70 ℃, the purification process was used in the experiment.

Examples 4 to 19

Animal biodiesel with reduced saturated fatty acid methyl ester content recovered in Example 3 was mixed with vegetable biodiesel (Preparation Examples 2 to 5) to prepare a mixed biodiesel. Types of plant biodiesel, the mixing ratio of the animal biodiesel and vegetable biodiesel of Example 3 are shown in Table 3.

Mixed Biodiesel (BD) Mixing volume ratio Example 3 Rapeseed Oil BD Example 4 Example 5 Example 6 Example 7 1: 0.25 1: 0.66 1: 1.5 1: 4 Example 3 Waste Cooking Oil BD Example 8 Example 9 Example 10 Example 11 1: 0.25 1: 0.66 1: 1.5 1: 4 Example 3 Soybean Oil BD Example 12 Example 13 Example 14 Example 15 1: 0.25 1: 0.66 1: 1.5 1: 4 Example 3 Camellia BD Example 16 Example 17 Example 18 Example 19 1: 0.25 1: 0.66 1: 1.5 1: 4 Example 3 Biodiesel from Uji with Reduced Saturated Fatty Acid Methyl Ester Content

Comparative Examples 1 to 16

In the same manner as in Example 4, but instead of the animal biodiesel of Example 3, a mixed biodiesel was prepared by mixing Uji-derived biodiesel (Preparation Example 1) with vegetable biodiesel without removing the saturated fatty acid methyl ester. Types of plant biodiesel, the mixing ratio of the Uji-derived biodiesel and the plant biodiesel of Preparation Example 1 are shown in Table 4.

Mixed Biodiesel (BD) Mixing volume ratio Uji BD: Rapeseed Oil BD Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 1: 0.25 1: 0.66 1: 1.5 1: 4 Uji BD: Waste Cooking Oil BD Comparative Example 5 Comparative Example 5 Comparative Example 7 Comparative Example 8 1: 0.25 1: 0.66 1: 1.5 1: 4 Uji BD: Soybean Oil BD Comparative Example 9 Comparative Example 10 Comparative Example 11 Comparative Example 12 1: 0.25 1: 0.66 1: 1.5 1: 4 Uji BD: Camellia BD Comparative Example 13 Comparative Example 14 Comparative Example 15 Comparative Example 16 1: 0.25 1: 0.66 1: 1.5 1: 4 Uji-derived biodiesel (Uji BD): no saturated fatty acid methyl ester

Property measurement test

1) Analysis of fatty acid methyl ester composition of biodiesel

The column for gas chromatography (GC) analysis (Agilent Technology, Little Falls, DE, USA) was SP ^TM -2560 (100 m × 0.25 mm Id, 0.2 μm film thickness, Supelco, Bellefonte, PA, USA) It was equipped with a flam ionization detector (FID) and an autoinjector. The injector and detector temperatures were set at 250 ° C and 260 ° C, respectively. The column oven temperature was maintained at 150 ° C. for 5 minutes and then increased to 4 ° C. per minute up to 220 ° C. for 20 minutes. The flow rate was 1 ml / min, the split ratio was 50: 1 and 1 μl of sample was injected to analyze the fatty acid methyl ester.

2) Low temperature filter plugging point (CFPP) measurement

The cold filter clogging point (CFPP) measurement of the mixed biodiesel prepared in Examples 4 to 19 and Comparative Examples 1 to 16 was analyzed using FPP 5GS (manufacturer PAC) which is an automatic cold filter clogging measuring instrument.

3) Kinematic viscosity measurement

Kinematic viscosity measurements of the mixed biodiesel prepared in Examples 4 to 19 and Comparative Examples 1 to 16 were analyzed using miniAV (manufacturer CANNON).

division Fatty acid methyl ester (FAME) composition (% by weight) CFPP
(℃) 14: 0 14: 1 16: 0 16: 1 18: 0 18: 1 18: 2 18: 3 20: 1 Etc Uji BD 3.50 1.33 25.13 7.09 8.29 53.53 1.13 - - 0 +8 Example 1 3.24 1.42 16.68 8.18 3.42 63.21 1.58 - 0.70 1.57 -One Example 2 3.01 1.73 8.07 9.83 0.40 73.09 1.93 - 0.77 1.17 -12 Example 3 1.59 2.44 1.62 12.37 0.16 78.33 2.53 - 0.61 0.35 -15 Rapeseed oil BD 0.05 - 4.09 - 2.02 63.32 21.08 7.31 1.54 0.59 -12 Waste Cooking Oil BD 0.25 0.03 14.11 0.80 3.85 34.48 41.91 3.85 - 0.72 -5 Soybean oil BD 0.08 0.02 11.15 0.09 4.20 27.03 51.36 5.55 - 0.52 -4 Camellia milk BD 0.05 - 4.03 - 1.86 65.84 18.76 7.65 1.18 0.63 -12 14: 0-myristic acid
14: 1-myristoleic acid
16: 0-palmitic acid
16: 1-palmitoleic acid
18: 0-stearic acid
18: 1-oleic acid
18: 2-linoleic acid
18: 3-linolenic acid
20: 1-gadoleic acid

As shown in Table 5, by the process of reducing saturated fatty acid methyl ester using urea in animal biodiesel, the unsaturated fatty acid methyl ester content of Examples 1 to 3 is relatively high, and in particular, the content of oleic acid is increased. Able to know. In addition, CFPP of Examples 1-3 had the effect that it is about 9-23 degreeC lower than before reducing saturated fatty acid methyl ester. Biodiesel derived from rapeseed oil (Production Example 2), biodiesel derived from waste cooking oil (Production Example 3), and soybean oil derived biodiesel (Production Example 4) had similar amounts of unsaturated fatty acid methyl esters (oleic acid, linoleic acid, linolenic acid, and gadoleic acid). The CFPP of rapeseed oil-derived biodiesel was excellent because the content of oleic acid is directly related to CFPP. This is a result consistent with the CFPP values of Examples 1-3.

division CFPP (℃) Kinematic viscosity
(40 ° C, mm ² / s) division CFPP (℃) Kinematic viscosity
(40 ° C, mm ² / s) Example 4 -14 4.550 Comparative Example 1 +6 4.940 Example 5 -15 4.643 Comparative Example 2 +3 4.882 Example 6 -14 4.849 Comparative Example 3 +3 4.843 Example 7 -12 5.033 Comparative Example 4 -8 4.800 Example 8 -10 4.325 Comparative Example 5 +6 5.162 Example 9 -8 4.296 Comparative Example 6 +5 5.378 Example 10 -5 4.190 Comparative Example 7 +1 5.592 Example 11 -3 4.249 Comparative Example 8 -2 5.813 Example 12 -18 4.401 Comparative Example 9 +6 4.850 Example 13 -15 4.402 Comparative Example 10 +4 4.803 Example 14 -8 4.418 Comparative Example 11 +2 4.735 Example 15 -6 4.428 Comparative Example 12 -One 4.668 Example 16 -12 4.486 Comparative Example 13 +6 5.009 Example 17 -12 4.552 Comparative Example 14 +4 5.062 Example 18 -13 4.736 Comparative Example 15 0 5.115 Example 19 -9 4.835 Comparative Example 16 -4 5.165

Table 6 shows the results of measuring the cold filter plugging point (CFPP) and kinematic viscosity of the mixed biodiesel prepared in Examples 4 to 19 and Comparative Examples 1 to 16. In case of kinematic viscosity, Examples 4 to 19 removed from saturated fatty acid methyl ester were generally lower than Comparative Examples 1 to 16, and there was no constant trend with respect to mixing ratio with vegetable biodiesel. However, in case of CFPP, Examples 4 to 19 showed lower values as the content of animal biodiesel with reduced saturated fatty acid methyl ester was lower than that of vegetable biodiesel. This is due to the high unsaturated fatty acid methyl ester content of the animal biodiesel of Example 3, especially in the case of mixing waste vegetable oil or soybean oil-derived biodiesel having a relatively high CFPP among vegetable biodiesel (Examples 8 to 15). Property improvement effect was obvious. In addition, it can be seen that rapeseed oil and camellia oil-derived biodiesel having a low cold filter clogging point can be further improved in low temperature fluidity by mixing with animal biodiesel having a reduced content of saturated fatty acid methyl ester.

As a result, according to the method for improving the low temperature fluidity of the biodiesel of the present invention, it was confirmed that animal and plant biodiesel can be used as fuel oil stably under domestic environmental conditions by improving the low temperature characteristics of animal and vegetable biodiesel.

Claims (6)

delete delete delete Reducing the content of saturated fatty acid methyl ester by adding urea to the animal fat derived biodiesel; And
Mixing the vegetable oil derived biodiesel with the animal fat derived biodiesel having a reduced content of saturated fatty acid methyl ester;
Low temperature fluidity improvement method of vegetable oil-derived biodiesel comprising a.
5. The method of claim 4, wherein the vegetable oil is at least one selected from rapeseed oil, camellia oil, soybean oil, and waste cooking oil.
5. The method of claim 4, wherein the volume ratio of the animal fat derived from biodiesel with reduced saturated fatty acid methyl ester content and the biodiesel derived from vegetable fat is 1: 0.25-4.

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