CN101302448B - Blending biodiesel - Google Patents

Abstract

The invention discloses blending biodiesel, which mainly comprises cottonseed oil biodiesel, tung oil biodiesel and illegal cooking oil biodiesel, and the volume ratio of the cottonseed oil biodiesel to the tung oil biodiesel to the illegal cooking oil biodiesel is 15-35: 10-60: 15-35. The invention has low cost, simple and easy operation process and environmental protection, integrates the advantages of various raw materials of biodiesel and petroleum diesel, and can better improve the performance of the biodiesel.

Description

A kind of biodiesel for blending

technical field

The invention belongs to the technical field of green and renewable energy, and in particular relates to an optimized biodiesel blended from various biodiesels.

Background technique

As a kind of green energy, biodiesel has the advantages of good combustion properties, renewability, and environmental friendliness, and has become the most promising petroleum substitute. Today, with the depletion of oil resources and the improvement of people's awareness of environmental protection, more and more attention has been paid to biodiesel, and the development of biodiesel has become the focus of research in various countries. At present, countries including the United States, the European Union, Japan and China are vigorously developing biodiesel. However, compared with the development of relatively mature petrochemical diesel, there are inevitably some problems in the commercialization of biodiesel, mainly manifested in high raw material cost, high viscosity, easy oxidation and poor storage resistance, and poor low-temperature start-up performance. In the traditional process, the low-temperature fluidity of biodiesel is generally improved by mixing biodiesel with petrochemical diesel or by adding additives. Such as CN1821350A provides a kind of method utilizing vegetable oil, additive to deploy biodiesel. CN1847369A increases the oxidation stability of biodiesel by adding some specific configuration antioxidant. However, most of these methods are relatively complicated and the production cost is relatively high, so they cannot be widely used so far.

The use of biodiesel can basically be divided into these three situations: 1. As a lubricity additive for petrochemical diesel, the general dosage is less than 5%; 2. As a blending component of petrochemical diesel, the general dosage is 20% -30%; 3. The use of pure biodiesel represented by Germany. At present, the vast majority of commercial applications of biodiesel appear in the form of co-firing.

Contents of the invention

The purpose of the present invention is to solve the problems of high raw material cost, high viscosity, easy oxidation, poor storage resistance and poor low-temperature flow performance in the current commercial promotion of biodiesel, and provide a simple and low-cost blending biodiesel.

The purpose of the present invention can be achieved through the following measures:

A kind of biodiesel for blending, the biodiesel for blending is mainly composed of cottonseed oil biodiesel, tung oil biodiesel and refined waste oil biodiesel, and its volume ratio is 15～35:10～60:15～35, preferably 20～ 30:10~50:20~30. The blending biodiesel can also be added with coconut oil biodiesel, wherein the volume ratio between coconut oil biodiesel, cottonseed oil biodiesel, tung oil biodiesel and refined waste oil biodiesel is 15～35:15～35:10～60 : 15-35, preferably 15-35: 15-35: 10-30: 15-35, most preferably 20-30: 20-30: 15-20: 20-30. The biodiesel for blending can also be added with rapeseed oil biodiesel, wherein the volume ratio of coconut oil biodiesel to rapeseed oil biodiesel is 15-35:10-25, preferably 20-30:15-20.

The biodiesel for blending can also be mixed with petrochemical diesel with a volume content of 60-98% to form a blend oil, and the volume content is 70-90%.

Coconut oil biodiesel, rapeseed oil biodiesel, cottonseed oil biodiesel, tung oil biodiesel and refined gutter oil biodiesel, respectively, starting from coconut oil, rapeseed oil, cottonseed oil, tung oil and refined gutter oil, using base-catalyzed ester Made by exchange. In the base-catalyzed transesterification process, the catalyst used is NaOH, the lower alcohol used is methanol, the molar ratio of alcohol to oil is 5-20:1, the reaction temperature is 30-75°C, and the reaction time is 30min-5h.

Concrete technical scheme of the present invention comprises the following steps:

1) Preparation of biodiesel

The invention uses coconut oil, rapeseed oil, cottonseed oil, tung oil and refined waste oil as raw materials to prepare biodiesel. The preparation of biodiesel from various raw materials is completed through alkali-catalyzed transesterification, and is used for the following preparation after separation, purification, washing and drying. The alcohols used in the base-catalyzed transesterification reaction is methyl alcohol, and the catalyzer is a strong base NaOH. The best experimental conditions are as follows: the preferred alcohol-oil mol ratio is about 6: 1, and the amount of the preferred catalyst is 1% of the oil weight. The preferred reaction The time is about 1-3h, the preferred reaction temperature is about 65°C, and the preferred stirring speed is about 600rpm.

2) Qualitative and quantitative analysis of fatty acid methyl ester components of biodiesel raw materials

Coconut oil, rapeseed oil, cottonseed oil and tung oil are all vegetable oils with abundant sources. Gutter oil is mainly recycled and processed waste oil from the catering industry. They all contain a lot of fatty acids and are excellent raw materials for biodiesel production. The present invention adopts GC/MS (mass spectrometry) to analyze the fatty acid methyl ester component of the biodiesel prepared by various raw materials, and its main component and content are as follows:

A. The composition and content of fatty acid methyl esters in coconut oil biodiesel are: lauric acid 44.1%, myristic acid 20.9%, palmitic acid 11.2%, oleic acid 9.2%, capric acid 5.3%, caprylic acid 4.8%, stearic acid 3.3%.

B. The composition and content of fatty acid methyl esters in rapeseed oil biodiesel are: 87.3% oleic acid, 6.4% palmitic acid, 2.3% eicosenoic acid, 1.2% hexadecenic acid, 1.1% erucic acid, hard Fatty acid 0.77%.

C. The composition and content of fatty acid methyl esters in cottonseed oil biodiesel are: linoleic acid 56.91%, palmitic acid 31.2%, stearic acid 5.03%, myristic acid 3.8%, hexadecenic acid 3.15%.

D. The composition and content of fatty acid methyl esters in tung oil biodiesel are: α-keto acid 71.4%, linoleic acid 15.3%, tridecanoic acid 3.8%, pentadecanoic acid 2.8%, arachidonic acid 1.3%.

E. The composition and content of fatty acid methyl esters in waste oil biodiesel are: 60.1% oleic acid, 24.6% palmitic acid, 5.8% stearic acid, 3.1% palmitic acid, 2.0% lauric acid, 1.8% myristic acid %, eicosenoic acid 1.3%, arachidonic acid 0.5%, eicosanoic acid 0.5%.

3) Mutual deployment of biodiesel from different raw materials

At present, biodiesel is generally used in practical applications by blending biodiesel prepared from a certain raw material with petrochemical diesel to form a blended oil. From the perspective of blending biodiesel mixtures of different raw materials with petrochemical diesel, the invention first studies the blending conditions of biodiesel with different raw materials, and then blends them with petrochemical diesel oil.

Considering the cost of raw materials, the carbon chain length of biodiesel fatty acid methyl ester, saturation and unsaturation and other factors, biodiesel prepared from different raw materials can be blended according to the following different proportions:

A. Analyze the composition and content of fatty acid methyl esters of biodiesel from various sources. It can be seen that the order of the content of unsaturated fatty acid methyl esters in biodiesel from different raw materials from high to low is: tung oil > rapeseed oil > waste oil > cottonseed oil > Coconut oil; and the content of saturated fatty acid methyl esters is just the opposite of that of unsaturated fatty acids. The degree of saturation and unsaturation of fatty acid methyl esters in biodiesel has a direct impact on the low temperature fluidity and oxidation stability of biodiesel. It is reported that when the content of saturated fatty acids in biodiesel is high, it is beneficial to improve the low-temperature fluidity of biodiesel; when the content of unsaturated fatty acids in biodiesel is high, it is beneficial to improve the oxidation stability of biodiesel. From the point of view of coordinating the two, a preferred proportioning is to allocate according to the ratio of coconut oil: rapeseed oil: cottonseed oil: tung oil: waste oil=30:15:20:15:20 (volume ratio).

B. Rapeseed oil can be divided into high erucic acid type and low erucic acid type due to different growth environments. In the raw material rapeseed oil used in the present invention, the content of erucic acid is very low, which belongs to low erucic acid type rapeseed oil. Furthermore, there is currently a high demand for edible oils in the market, leading to an increase in the price of rapeseed oil. Considering that there are different types of rapeseed oil, which are not universal, and the price and cost are high, it is not studied in this blending experiment. A kind of preferred proportioning from this point of view is to allocate according to the ratio of coconut oil: cottonseed oil: tung oil: waste oil=20:30:20:30 (volume ratio).

C. Non-edible vegetable oils such as cottonseed oil, tung oil, and gutter oil are cheaper than edible oils such as rapeseed oil and cottonseed oil. As raw materials for biodiesel production, there is no problem of competing with others for food. At the same time, the unsaturated fatty acid content of cottonseed oil and gutter oil biodiesel is similar, about 60%-70%, while the unsaturated fatty acid content of tung oil biodiesel occupies a dominant position. A kind of preferred proportioning from this point of view is to allocate according to the ratio of cottonseed oil: tung oil: waste oil=25:50:25 (volume ratio).

4) Blending of biodiesel and petrochemical diesel

The biodiesel mixtures of the three proportion systems were blended into 0# diesel oil at the proportions of 100%, 30%, 20%, 10%, and 0%, respectively, to form three blending oils with different proportions, and these blending oils corresponded to Ground means B100, B30, B20, B10, B0.

5) Determination of some important properties of blend oil

According to GB/T265, respectively measure and compare the sulfur content of blend oils B100, B30, B20, B10 and B0, the results are shown in Table 1; according to GBT5538-2005, respectively measure and compare the peroxidation of blend oils B100, B30, B20, B10 and B0 The results are shown in Table 2; the cold filter points of blend oils B100, B30, B20, B10 and B0 were measured and compared in accordance with SH/T0248, and the results are shown in Table 3.

The present invention, through the research on the blending effect of biodiesel prepared from different raw materials, largely solves some deficiencies in the practical application of biodiesel and enables the advantages of biodiesel to be brought into full play. The present invention conception is newer, has reached actual benefit, mainly has the following advantages:

1. Cost:

1) raw material cost reduction: the present invention utilizes renewable vegetable oil coconut oil, rapeseed oil, cottonseed oil, tung oil as raw material, and the source of these raw materials is wide; Wherein, the use of these several non-edible oils of cottonseed oil, tung oil, waste oil, Avoiding the problem of competing with others for food. As a raw material for biodiesel preparation, gutter oil can also solve the problem of waste oil in the catering industry and purify sewage discharge. The deployment and use of biodiesel from different raw materials facilitates the over-reliance on a certain raw material in the large-scale production of biodiesel, and alleviates the limitation of large-scale production affected by the origin of raw materials.

2) Reduced production cost: the mutual deployment of biodiesel and petrochemical diesel is simple and easy to operate. In contrast, the production process is simple and the production cost is reduced.

2. In terms of environmental protection: the main performance is that the sulfur content in biodiesel is low, so that the emission of sulfur dioxide and sulfide is low; biodiesel does not contain aromatic alkanes that will pollute the environment, so the exhaust gas is less harmful to the human body than diesel. Therefore, adding a certain amount of biodiesel to mineral diesel can achieve a good environmental protection effect.

3. Improving the performance of biodiesel: The performance of biodiesel can be better improved by blending different raw materials of biodiesel and petrochemical diesel.

1) Improve oxidation stability: When the content of unsaturated fatty acids in pure biodiesel is high, it is easy to be oxidized; the peroxide value of blended biodiesel is obviously lower than that of pure biodiesel, which is beneficial for long-term storage.

2) Improve low-temperature fluidity: The cold filter point of blended biodiesel is lower than that of petrochemical diesel, and the low-temperature fluidity is better.

Detailed ways

The present invention will be further described below in conjunction with specific examples.

Example 1:

Weigh 100 g of cottonseed oil into a three-neck flask equipped with a stirring device, a condensing reflux device and a thermometer, and place it in a constant temperature water bath device with a preset temperature of about 65°C. Take about 1% NaOH of oil weight, dissolve in anhydrous methanol, the molar ratio of anhydrous methanol and cottonseed oil is 6:1. Mix anhydrous methanol in which NaOH is dissolved with coconut oil, and stir for about 2 hours at a rotation speed of about 600r/min. After the reaction is completed, transfer it to a separatory funnel to stand still for more than 8 hours, and the upper layer is the crude biodiesel product. Take the crude biodiesel in the upper layer, and evaporate excess methanol at 80°C. Wash the evaporated biodiesel several times with distilled water until the washing water is clear and transparent. Finally, excess water is removed with anhydrous NaSO ₄ , and biodiesel product is obtained after filtration.

The preparation of coconut oil biodiesel, rapeseed oil biodiesel, tung oil biodiesel and gutter oil biodiesel is the same as cottonseed oil biodiesel.

Example 2:

Get 30 parts by volume of coconut oil biodiesel, 15 parts by volume of rapeseed oil biodiesel, 20 parts by volume of cottonseed oil biodiesel, 15 parts by volume of tung oil biodiesel and 20 parts by volume of waste oil biodiesel Mix well in tube 1. This blended biodiesel is denoted B100. Take the mixed biodiesel in test tube 1 and mix them with mineral diesel respectively at mixing ratios of 30%, 20%, 10%, and 0% to form a blended oil. The blended oils are correspondingly expressed as B30, B20, B10, B0.

Follow GB380-77 to measure the sulfur content of blend oil B100, B30, B20, B10 and B0 respectively; follow GBT5538-2005 to measure the peroxide value of blend oil B100, B30, B20, B10 and B0 respectively; follow SH/T0248 to measure the blend Cold filter point for oils B100, B30, B20, B10 and B0. The measurement results of sulfur content, peroxide value and cold filtration point are shown in Table 1-3.

Example 3:

20 parts by volume of coconut oil biodiesel, 30 parts by volume of cottonseed oil biodiesel, 20 parts by volume of tung oil biodiesel and 30 parts by volume of waste oil biodiesel of Example 1 were placed in test tube 2 and fully mixed. This blended biodiesel is denoted B100. Take the mixed biodiesel in test tube 2 and mix them with mineral diesel respectively at mixing ratios of 30%, 20%, 10%, and 0% to form a blended oil. The blended oils are correspondingly expressed as B30, B20, B10, B0.

Follow GB380-77 to measure the sulfur content of blend oil B100, B30, B20, B10 and B0 respectively; follow GBT5538-2005 to measure the peroxide value of blend oil B100, B30, B20, B10 and B0 respectively; follow SH/T0248 to measure the blend Cold filter point for oils B100, B30, B20, B10 and B0.

The measurement results of sulfur content, peroxide value and cold filtration point are shown in Table 1-3.

Example 4:

25 parts by volume of cottonseed oil biodiesel, 50 parts by volume of tung oil biodiesel and 25 parts by volume of waste oil biodiesel of Example 1 were placed in test tube 3 for thorough mixing. This blended biodiesel is denoted B100. Take the mixed biodiesel in test tube 3 and mix them with mineral diesel respectively at mixing ratios of 30%, 20%, 10%, and 0% to form a blended oil. The blended oils are correspondingly expressed as B30, B20, B10, B0.

Follow GB380-77 to measure the sulfur content of blend oil B100, B30, B20, B10 and B0 respectively; follow GBT5538-2005 to measure the peroxide value of blend oil B100, B30, B20, B10 and B0 respectively; follow SH/T0248 to measure the blend Cold filter point for oils B100, B30, B20, B10 and B0.

The measurement results of sulfur content, peroxide value and cold filtration point are shown in Table 1-3.

Example 5:

Get 10 parts by volume of coconut oil biodiesel, 10 parts by volume of rapeseed oil biodiesel, 10 parts by volume of cottonseed oil biodiesel, 10 parts by volume of tung oil biodiesel and 10 parts by volume of waste oil biodiesel Mix well in tube 3. This blended biodiesel is denoted B100. Take the mixed biodiesel in test tube 3 and mix them with mineral diesel respectively at mixing ratios of 30%, 20%, and 10% to form a blended oil.

It can be seen from Table 1 that the sulfur content of this kind of biodiesel for blending is significantly lower than that of 0# diesel, and the impact of its combustion on air quality is far lower than that of petrochemical diesel, and its environmental protection effect is better. It can be seen from Table 2 that the peroxide value of the biodiesel for blending decreases significantly with the addition of petrochemical diesel, which improves the oxidation stability of biodiesel and is beneficial to its long-term storage. It can be seen from Table 3 that the cold filter point of this blending biodiesel is lower than that of 0# diesel, and the low temperature flow performance is better.

Table 1 Sulfur content comparison table of each case

Table 2 The peroxide value comparison table of each case

Table 3 Comparison table of cold filtration points of each case

Claims (8)

1. A biodiesel for blending is characterized in that the biodiesel for blending is mainly composed of cottonseed oil biodiesel, tung oil biodiesel and refined waste oil biodiesel, and its volume ratio is 15～35: 10～60: 15～35 . 2. The biodiesel for blending according to claim 1, characterized in that the biodiesel for blending also includes coconut oil biodiesel, wherein the volume ratio between coconut oil biodiesel and cottonseed oil biodiesel is 15～35:15 ~35. 3. The blending biodiesel according to claim 2, characterized in that the volume ratio between the coconut oil biodiesel and cottonseed oil biodiesel is 20-30:20-30. 4. The biodiesel for blending according to claim 1, characterized in that the biodiesel for blending also includes rapeseed oil biodiesel, wherein the volume ratio of rapeseed oil biodiesel to cottonseed oil biodiesel is 10～25:15 ~35. 5. The blending biodiesel according to claim 4, characterized in that the volume ratio of the rapeseed oil biodiesel to the cottonseed oil biodiesel is 15-20:20-30. 6. according to the described blending biodiesel of claim 1,2 or 4, it is characterized in that described coconut oil biodiesel, rapeseed oil biodiesel, cottonseed oil biodiesel, tung oil biodiesel and refining waste oil biodiesel, Coconut oil, rapeseed oil, cottonseed oil, tung oil and refined gutter oil are respectively used as raw materials and prepared by alkali-catalyzed transesterification. 7. The blending biodiesel according to claim 6 is characterized in that in the base-catalyzed transesterification process, the catalyst used is NaOH, and the low-carbon alcohol used is methyl alcohol. 8. The biodiesel for blending according to claim 6, characterized in that in the alkali-catalyzed transesterification process, the molar ratio of alcohol to oil is 5-20:1, the reaction temperature is 30-75°C, and the reaction time is 30min-5h.