Method for improving quality of biodiesel

[0019] Example 1

[0020] The liquid lipase derived from Candida antarctica (Candida antarctica) of 10g gutter oil, 10% water based on oil quality and 200 standard enzyme activities (200U/g soybean oil) based on unit oil quality was placed in a suitable enzyme Catalyzed one-stage or multi-stage enzyme reactors. Control the temperature at 35°C, and then add ethanol with a molar ratio of 4.5:1 based on oil at a constant speed within 3 hours. After reacting for 6 hours, the conversion rate of effective oil to biodiesel is 90%, and then the reaction liquid is left to stand for phase separation, and the heavy phase and light phase containing enzyme are separated. In the heavy phase, the enzyme protein is further recovered by membrane separation, and an organic membrane with a molecular weight cut-off of 15,000 Da is selected for the recovery of the above-mentioned lipase. The recovery rate of the enzyme protein is as high as 95%, and the residual amount of the by-product glycerol in the recovered enzyme liquid is less than 5%. Enzymes can be reused. The light phase flows into the immobilized enzyme reactor (the immobilized lipase derived from Aspergillus oryzae based on 200 standard enzyme activities per unit oil mass is housed), and the methanol that is 1:1 based on the crude biodiesel molar ratio is added simultaneously, To carry out the reaction, the temperature was controlled at 20°C, and the methanol was added at a uniform speed within 1 hour. During this reaction, the figure 1 The online dehydration shown (membrane dehydration device including organic membrane, inorganic membrane or ceramic membrane and including or Water absorption device including molecular sieve). After 4 hours of reaction, the conversion rate of effective oil to biodiesel in the system is 97%. The crude biodiesel phase is further flowed into the immobilized enzyme reactor (the immobilized lipase derived from Aspergillus oryzae based on 200 standard enzyme activities per unit oil mass is equipped with), and it is 1 based on the crude biodiesel molar ratio to be added simultaneously: 1 of dimethyl carbonate, and reacted at a temperature of 20°C. During this reaction, the figure 1 The online dehydration shown (membrane dehydration device including organic membrane, inorganic membrane or ceramic membrane and including or Water absorption device including molecular sieve). After reacting for 0.5 hours, the conversion rate of effective oil to biodiesel in the system was 98.5%, the total glycerin content was 0.18%, and the acid value was 0.3 mg KOH/g.

[0021] Example 2

[0022] Put 10g of lard, 4% water based on oil mass and 300 standard enzyme activities based on unit oil mass into the liquid lipase derived from Aspergillus oryzae, which is placed in a primary or multi-stage enzyme suitable for enzymatic catalysis in the reactor. Control the temperature at 40°C, and then add methanol with a molar ratio of 5:1 based on oil at a uniform rate within 4 hours. After reacting for 8 hours, the conversion rate of effective oil to biodiesel was 91%. Then the reaction solution is centrifuged to separate the heavy phase containing enzyme and the light phase containing crude biodiesel. In the heavy phase, the enzyme protein is further recovered by membrane separation, and an organic membrane with a molecular weight cut-off of 15,000 Da is selected for the recovery of the above-mentioned lipase. The recovery rate of the enzyme protein is as high as 95%, and the residual amount of the by-product glycerol in the recovered enzyme liquid is less than 5%. Enzymes can be reused. Light phase flows into the enzyme reactor that immobilized enzyme is housed again (the immobilized lipase derived from Aspergillus oryzae based on 200 standard enzyme activities per unit oil mass is housed), adding simultaneously based on crude biodiesel mol ratio is 2: 1 of methanol for the reaction. The temperature was controlled at 20°C, and the addition of methanol was completed within 1 hour. During this reaction, the figure 1 In-line dehydration shown (water absorption device including organic membrane). After 4 hours of reaction, the conversion rate of effective oil to biodiesel in the system is 98%. Further, the crude biodiesel phase flows into the enzyme reactor equipped with immobilized enzyme (the immobilized lipase derived from Aspergillus oryzae based on 200 standard enzyme activities per unit oil mass is housed), and the crude biodiesel is added simultaneously Dimethyl carbonate at a ratio of 0.2:1 for the reaction. The temperature is controlled at 20°C. During this reaction, the figure 1 In-line dehydration shown (water absorption device including organic membrane). After reacting for 1 hour, the conversion rate of effective oil into biodiesel in the system was 98.8%, the total glycerol was 0.12%, and the acid value was 0.3 mg KOH/g.

[0023] Example 3

[0024] 10g of palmitoleic acid, 5% water based on oil mass and liquid lipase derived from Thermomyces lanuginosus (Thermomyces lanuginosus) based on 200 standard enzyme activities per unit oil mass and 400 standard enzyme activities based on unit oil mass The liquid lipase derived from Aspergillus oryzae is placed in a one-stage or multi-stage enzyme reactor suitable for enzyme catalysis. Control the temperature at 45°C, and then add ethanol with a molar ratio of 6:1 based on oil at a constant speed within 2 hours. After reacting for 5 hours, the conversion rate of effective oil to biodiesel is 92%, and then the reaction solution is centrifuged to separate the heavy phase containing enzyme and the light phase containing crude biodiesel. In the heavy phase, the enzyme protein is further recovered by membrane separation, and an inorganic membrane with a molecular weight cut-off of 15,000 is selected for the recovery of the above-mentioned lipase. The recovery rate of the enzyme protein is as high as 95%, and the residual amount of by-product glycerol in the recovered enzyme liquid is less than 5%. Enzymes can be reused. The separated light phase enters the immobilized enzyme reactor (the immobilized lipase derived from Aspergillus oryzae with 200 standard enzyme activities based on the unit oil mass) is added, and the molar ratio based on crude biodiesel is 1:1. ethanol for the reaction. The temperature was controlled at 20°C, and ethanol was added at a uniform speed within 1 hour. During this reaction, the figure 1 Air stripping is shown for in-line dehydration. After reacting for 5 hours, the conversion rate of effective oil to biodiesel in the system is 97.8%. Further, the crude biodiesel phase enters the immobilized enzyme reactor (the immobilized lipase derived from Candida antarctica based on the unit oil mass of 200 standard enzyme activities is installed), and the molar ratio of crude biodiesel based on crude biodiesel is 1 :1 diethyl carbonate for reaction. During this reaction, the figure 1 In-line dehydration shown. The so-called air stripping online dehydration means that one side of the enzyme reactor is connected to an anhydrous ethanol tank, and the other side is connected to a vacuum pump and a condenser. The vacuum in the control system is 15MPa, the temperature of the condenser is 2°C, and the temperature of the enzyme reactor is 30°C. After reacting for 1 hour, the yield of short-chain fatty acid esters in the system was 98.6%, the total glycerol content was 0.1%, and the acid value was 0.4 mg KOH/g. .