TWI485242B - Manufacturing method of biodiesel - Google Patents

Description

Biomass diesel manufacturing method

The present invention relates to a method for producing biodiesel, and more particularly to a method for producing biodiesel from a supercritical fluid.

Biodiesel (ie fatty acid methyl ester, FAME for short) is a kind of biomass energy, which can replace general petrochemical fuel and alleviate the global warming trend.

A method for producing conventional biodiesel, comprising a conventional base catalysis method (catalyzing a catalyst such as a basic substance such as sodium hydroxide or potassium hydroxide) or a supercritical alcohol method (using a supercritical alcohol for ester transesterification) ), free fatty acids in automatic, vegetable oils or waste oils, converted into useful biodiesel. However, the raw diesel oil obtained from the former is liable to remain alkaline and a large amount of glycerin by-products are derived (the reaction is as shown in Fig. 1), which is difficult to remove, so the conversion rate is not good; although the latter has no catalyst, However, there are still many glycerin by-products, which are difficult to remove.

A method for producing conventional biodiesel, as shown in the Patent No. 201105789 of the Republic of China, is to first utilize a large amount of acetic acid to hydrolyze fatty acids on the leprosy seed oil, and then use a methanol solution for supercritical alcoholysis to obtain biodiesel. The conventional method requires the two-stage reaction (including the secondary hydrolysis reaction and the supercritical alcoholysis reaction) to complete the production of the biomass diesel, and the secondary hydrolysis reaction requires a large amount of acetic acid, and then is separated from the acetic acid. Hydrolysis of fatty acids for subsequent reactions is not only cumbersome, but also does not improve the problem of excessive glycerin by-products, and may not be effectively applied to the production of the biodiesel.

Japanese scholars also provide a method for the manufacture of conventional biodiesel, which is catalyzed by ethyl acetate (Shiro Saka & Yohei Isayama, A new process for Catalyst-free production of biodiesel using supercritical methyl acetate, 2009), preparation of biodiesel by using supercritical dimethyl carbonate (Zul Ilham & Shiro Saka, Dimethyl carbonate as potential reactant in non-catalytic biodiesel production by Supercritical method, 2009), although the manufacturing method of the conventional biodiesel can effectively improve the formation of glycerin by-products, however, the dimethyl carbonate needs to be synthesized by chemical technology, and the synthesis cost is high and the operation is complicated, and the production is still in progress. The bottleneck of biodiesel.

In addition, in order to maintain the manufacturing quality of the product (biodiesel), the production method of the above-mentioned conventional biodiesel is preferred to produce biomass diesel raw materials by using vegetable oils and fats, and it is often necessary to additionally perform extraction treatment to obtain vegetable oils. Manufacturing cost and manufacturing time of proliferative diesel.

Therefore, it is necessary to provide a method for facilitating the production of biodiesel to improve the problems of the prior art described above.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method for producing biodiesel by using a low cost and readily available material for the production of biodiesel.

Another object of the present invention is to provide a method for producing a biodiesel which is capable of reducing the production of glycerin by-products while avoiding an increase in manufacturing cost.

Another object of the present invention is to provide a method for producing biodiesel, which can directly produce biodiesel from various edible oils or waste edible oils, and reduce the process.

In order to achieve the foregoing object, the technical means and the efficiencies achievable by the technical method include: a method for producing raw diesel fuel, comprising: first driving a methanol into a tank, heating the methanol Up to above its critical temperature to obtain a supercritical methanol; a reaction substrate is driven into the above-mentioned tank, wherein the reaction substrate comprises acetic acid and a feedstock oil having a molar ratio of 3:1, the methanol and the feedstock oil The molar ratio is 60:1; finally, a supercritical carbon dioxide is introduced to the above The tank body is such that the total pressure of the supercritical methanol and the supercritical carbon dioxide is above 10 MPa; wherein the supercritical methanol, the feedstock oil, the acetic acid and the supercritical carbon dioxide are in the above-mentioned tank at a temperature of The reaction is carried out at a temperature of 240-500 ° C under a parameter of 8.1-50 MPa for 0.1-1.5 hours; to obtain a primary diesel oil.

In the method for producing a biodiesel according to the present invention, the volume ratio of the methanol to the raw material oil is 2.5:1, and the volume ratio of the acetic acid to the raw material oil is 1:6.4.

In the method for producing a biodiesel according to the present invention, the methanol is heated to 240 to 250 °C.

In the method for producing a biodiesel according to the present invention, the raw material oil is selected from the group consisting of vegetable oils, animal oils, waste cooking oils, and other fats and oils containing glycerides and fatty acids.

In the method for producing a biodiesel according to the present invention, the raw material oil is a salad oil (soybean oil).

In the method for producing a biodiesel according to the present invention, the supercritical methanol, the feedstock oil, the acetic acid and the supercritical carbon dioxide are reacted in the above-mentioned tank at a parameter of 280 ° C and 20 MPa.

In the method for producing a biodiesel according to the present invention, the reaction time of the supercritical methanol, the feedstock oil, the acetic acid and the supercritical carbon dioxide in the tank is 90 minutes.

According to the above technical features, the method for producing biodiesel according to the preferred embodiment of the present invention can be carried out before cost saving and operation time, and the production of glycerin by-products can be reduced, and the advantages of recycling and utilization of waste edible oil can be achieved.

〔this invention〕

1‧‧‧High pressure pump

11‧‧‧Intake valve

2‧‧‧High pressure pump

21‧‧‧Intake valve

3‧‧‧High pressure tank

4‧‧‧heating parts

A‧‧‧temperature control unit

B‧‧‧pressure control unit

V‧‧‧Exhaust valve

Fig. 1 is a reaction formula for the formation of glycerin by-products of conventional techniques.

Figure 2 is one of the chemical reaction formulas of the preferred embodiment of the present invention.

Figure 3 is a second chemical reaction scheme of the preferred embodiment of the present invention.

Figure 4 is a third chemical reaction scheme of the preferred embodiment of the present invention.

Figure 5 is a diagram of a biodiesel manufacturing apparatus in accordance with a preferred embodiment of the present invention.

The above and other objects, features and advantages of the present invention will become more <RTIgt; The method for producing a quality diesel oil comprises the steps of: driving a methanol into a tank; heating the methanol to above a critical temperature to obtain a supercritical methanol; and driving a reaction substrate into the tank; The reaction substrate comprises acetic acid and a feedstock oil having a molar ratio of 1:1 to 5:1, and the molar ratio of the methanol to the raw material oil is 20:1 to 90:1; finally, a supercritical carbon dioxide is introduced to the above a tank body, wherein the total pressure of the supercritical methanol and the supercritical carbon dioxide is 10 MPa or more; wherein the supercritical methanol, the feedstock oil, the acetic acid and the supercritical carbon dioxide are in the tank. The reaction is carried out for 0.1-1.5 hours under the conditions of a temperature of 240-500 ° C and a pressure of 8.1-50 MPa (MPa); to obtain a primary diesel oil.

More specifically, the method for producing biodiesel according to a preferred embodiment of the present invention utilizes an appropriate amount of acetic acid as a reaction substrate for transesterification, which catalyzes the hydrolysis of fatty acids while participating in the second and fourth figures. The reaction, therefore, the acetic acid can be fully used in the method of producing the biodiesel of the present embodiment, and the reaction with methanol can be continued without separately operating the separation step. Wherein, the molar ratio of the acetic acid to the raw material oil is preferably 3:1, and the volume ratio is about 1:6.4, and the molar ratio of the methanol to the raw material oil is preferably 60:1, and the volume ratio is about 2.5:1. This makes the acetic acid work completely and reduces the yield of glycerol.

Please refer to Figures 1 to 3 again, the above acetic acid can assist fatty acids from raw materials. The oil is free and the free fatty acid is reacted with methanol to produce a glycerol by-product (i.e., as shown in Figure 1). However, an appropriate amount of acetic acid employed in the preferred embodiment of the present invention can be further reacted with the glycerin by-product (i.e., as shown in Figure 4) to form a glyceride to reduce the production of glycerin by-products. Furthermore, the above-mentioned acetic acid can be further reacted with methanol (that is, as shown in FIG. 2) to produce methyl acetate and Dimethyl carbonate, which is more advantageous for improving the conversion of the biodiesel. Rate and reduce the production of glycerol by-products.

The methanol of the present embodiment is pumped into the above-mentioned tank by a pump. The methanol is preferably 99% methanol, and the acetic acid is preferably 99% glacial acetic acid to make the methanol and the methanol. The acetic acid can be completely reacted, and the reaction described in the preceding paragraph is carried out in sequence without separately requiring an additional step to separate the unreacted acetic acid. Wherein, the reaction time is about 0.1-1.5 hours, and the reaction time depends on the size of the reaction system (such as the above-mentioned tank), and the larger the reaction system, the longer the reaction time, for example, 6 ml (ml) The reaction system has a reaction time of about 15 minutes, and a reaction time of 150 ml (ml) of the reaction system is about 1.5 hours.

Further, the above methanol is heated to a temperature above the critical temperature, preferably 240 ° C to 500 ° C, more preferably 280 ° C, to obtain the supercritical methanol described above, and the auxiliary reaction (ie, the reaction shown in the first figure) is carried out. And increase the reaction rate.

Further, the above-mentioned raw material oil may be any oil having glycerolipid and fatty acid, and includes a combination of vegetable oil, animal oil, waste cooking oil or any of the above-mentioned various types of fats and oils. In this embodiment, waste cooking oil is preferably used. The method of the embodiment regenerates and converts the spent cooking oil to help reduce the amount of waste cooking oil.

In addition, the final supercritical carbon dioxide can increase the solubility of the supercritical methanol and the reaction substrate, and stabilize the pressure value in the tank. The total pressure of the supercritical carbon dioxide and the supercritical methanol is 10 MPa (MPa). Above, it is preferably 20-50 MPa, more preferably 20 MPa.

For example, a practical implementation of a preferred embodiment of the present invention provides a The biomass diesel manufacturing device shown in FIG. 5 has two high-pressure pumps 1, 2; a high-pressure tank body 3; and a temperature rising member 4, and the two high-pressure pumps 1 and 2 respectively respectively take methanol and super The critical carbon dioxide is introduced into the high pressure tank 3 and heated by the temperature rising member 4, and each of the two high pressure pumps 1 and 2 is provided with an intake valve 11, 21 for regulating the access rate of the supercritical carbon dioxide or methanol. The high pressure tank body 3 is connected to a temperature control unit a and a pressure control unit b to adjust the temperature and pressure of the high pressure tank body 3 through the temperature control unit a and the pressure control unit b. In addition, the high pressure tank body 3 is additionally connected to an exhaust valve v for product discharge.

In the actual embodiment, 75.93 milliliters (ml) of methanol is introduced into the high-pressure tank body 3 (150 ml of the high-pressure tank body in the actual embodiment) by the high-pressure pump 1 described above, and the temperature rising member 4 is used. The methanol is heated to 280 ° C, the methanol is converted to a supercritical state, and then mixed with the reaction substrate, the reaction substrate is also pumped by the above high pressure 1 and has a maximum flow rate of 10 ml per minute (10 ml / Min), and the reaction substrate consists of 30 ml (ml) of salad oil (ie soybean oil) and 4.68 ml (ml) of 99% acetic acid (wherein the molar ratio of methanol/salad oil is 60; acetic acid / The molar ratio of salad oil is 3). At this time, the supercritical carbon dioxide is further introduced into the high-pressure tank body 3 from the high-pressure pump 2 at a maximum flow rate of 200 ml (200 ml/min) per minute to make the total pressure of the supercritical carbon dioxide and the supercritical methanol. The high-pressure tank body 3 is allowed to react at 280 ° C and 20 MPa for 90 minutes, and the produced diesel fuel can be collected from the above-mentioned exhaust valve v. Please refer to the first table, the raw diesel produced by the above-mentioned actual implementation, after measuring and referring to the equation of Figure 1, calculated by the following formula, can measure the conversion rate of biodiesel to 97.83%. The amount of glycerin by-product produced is reduced by about 30.2% compared to the conventional catalyst method (base catalysis method) or the supercritical alcohol method.

Formula: (glycerol molecular weight × 1) / (methanol molecular weight × 3 + triglyceride molecular weight × 1) × 100% = glycerin yield.

Therefore, the method for producing biodiesel according to the preferred embodiment of the present invention has the effect of effectively reducing the production of glycerin by-products, and the method for producing the biodiesel utilizes an appropriate amount of acetic acid and methanol as a reaction substrate, which can be processed not only in a single stage. In the step, the production of biodiesel can further eliminate the extra step of separating the reaction substrate which is not completely reacted, and has the effects of cost saving and operation time.

In addition, the method for producing biodiesel according to the preferred embodiment of the present invention can be applied to the treatment of various edible oils and even discarded edible oils, which is beneficial to the recycling of discarded edible oils, and can take into consideration the quality of the produced diesel products. It is the efficacy of the invention.

While the invention has been described in connection with the preferred embodiments described above, it is not intended to limit the scope of the invention. The technical scope of the invention is protected, and therefore the scope of the invention is defined by the scope of the appended claims.

Claims (8)

A method for producing raw diesel fuel comprises: first driving a methanol into a tank, heating the methanol to above a critical temperature thereof to obtain a supercritical methanol; and driving a reaction substrate into the tank, wherein the The reaction substrate comprises acetic acid and a feedstock oil having a molar ratio of 3:1, and the molar ratio of the methanol to the raw material oil is 60:1; finally, a supercritical carbon dioxide is introduced into the above-mentioned tank to make the supercritical methanol described above. The total pressure of the supercritical carbon dioxide is more than 10 MPa; wherein the supercritical methanol, the feedstock oil, the acetic acid and the supercritical carbon dioxide are in the above-mentioned tank at a temperature of 240-500 ° C and a pressure of 8.1-50. The reaction was carried out for 0.1 to 1.5 hours under the parameters of megapascal; to obtain a biomass diesel. The method for producing a biodiesel according to the above aspect of the invention, wherein the volume ratio of the methanol to the raw material oil is 2.5:1. The method for producing a biodiesel according to the above aspect of the invention, wherein the volume ratio of the acetic acid to the raw material oil is 1:6.4. The method for producing a biodiesel according to the above aspect of the invention, wherein the methanol is heated to 240 to 500 °C. The method for producing a biodiesel according to the above aspect of the invention, wherein the raw material oil is selected from the group consisting of vegetable oil, animal oil, waste cooking oil, and other fats and oils containing glycerides and fatty acids. The method for producing a biodiesel according to the fifth aspect of the invention, wherein the raw material oil is a salad oil. The method for producing a biodiesel according to claim 1, wherein the supercritical methanol, the feedstock oil, the acetic acid and the supercritical carbon dioxide are reacted in the above-mentioned tank at a parameter of 280 ° C and 20 MPa. . The method for producing a biodiesel according to the above aspect of the invention, wherein the reaction time of the supercritical methanol, the feedstock oil, the acetic acid and the supercritical carbon dioxide in the tank is 90 minutes.