# US 10,246,644 B2 · Method for preparing biodiesel

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- Number: US 10,246,644 B2
- Document ID: US10246644B2
- Status: Granted
- Kind: B2
- Application number: 14/005,038
- Filed: 2011-11-29
- Published: 2014-05-08
- Granted: 2019-04-02
- Earliest claimed: 2011-03-15
- Assignees: Tsinghua University
- Applicants: Wei Du; Dehua Liu; Luole Zhu
- Inventors: Wei Du; Dehua Liu; Luole Zhu
- Web page: https://patentgrep.com/patent/US10246644B2

## CPC

- C10G 3/00: Production of liquid hydrocarbon mixtures from oxygen-containing organic materials, e.g. fatty oils, fatty acids (production from non-melting solid oxygen-containing carbonaceous materials C10G1/00)
- C10L 1/026: {for compression ignition}
- C11C 3/003: {by esterification of fatty acids with alcohols (C11C3/02 takes precedence)}
- C12P 7/649: Biodiesel, i.e. fatty acid alkyl esters
- C10L 2200/0476: Biodiesel, i.e. defined lower alkyl esters of fatty acids first generation biodiesel
- C10L 2290/26: Composting, fermenting or anaerobic digestion fuel components or materials from which fuels are prepared
- C10L 2290/548: Membrane- or permeation-treatment for separating fractions, components or impurities during preparation or upgrading of a fuel
- Y02E 50/10: Biofuels, e.g. bio-diesel
- Y02P 30/20: using bio-feedstock
- C10G: CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION (cracking to hydrogen or synthesis gas C01B; cracking or pyrolysis of hydrocarbon gases to individual hydrocarbons or mixtures thereof of definite or specified constitution C07C; cracking to cokes C10B); RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
- C10L: FUELS NOT OTHERWISE PROVIDED FOR; NATURAL GAS; SYNTHETIC NATURAL GAS OBTAINED BY PROCESSES NOT COVERED BY SUBCLASSES C10G OR C10K; LIQUIFIED PETROLEUM GAS; USE OF ADDITIVES TO FUELS OR FIRES; FIRE-LIGHTERS
- C11C: FATTY ACIDS FROM FATS, OILS OR WAXES; CANDLES; FATS, OILS OR FATTY ACIDS BY CHEMICAL MODIFICATION OF FATS, OILS, OR FATTY ACIDS OBTAINED THEREFROM
- C12P: FERMENTATION OR ENZYME-USING PROCESSES TO SYNTHESISE A DESIRED CHEMICAL COMPOUND OR COMPOSITION OR TO SEPARATE OPTICAL ISOMERS FROM A RACEMIC MIXTURE {(brewing of beer C12C; producing vinegar C12J; producing specific peptides or proteins C07K; producing enzymes C12N9/00; DNA or RNA concerning genetic engineering, vectors, e.g. plasmids, or their isolation, preparation or purification C12N15/00; measuring or testing processes involving enzymes or microorganisms C12Q; measuring or testing processes involving nucleic acid amplification reactions C12Q1/6844; fermentation processes to form a food composition, A21 or A23; compounds in general, see the relevant compound class, e.g. C01, C07)}
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS

## Abstract

The present invention provides a method for preparing biodiesel, comprising: adding oil and fat, short-chain alcohol, water, and liquid lipase into a single-stage or multi-stage enzyme reactor; then separating the reaction fluid into an enzyme-containing heavy phase and a light phase; recovering and reusing the enzyme in the heavy phase; using the light phase for subsequent conversion by immobilized lipase; flowing the light phase and the short-chain alcohol into single-stage or multi-stage enzyme reactor containing an immobilized lipase; performing online dehydration during the whole reaction process or part of the reaction process. In the method of the invention for preparing biodiesel, no preprocessing is required for the oil and fat feedstock in the earlier stage of catalysis process by liquid lipase, and the conversion ratio from oil and fat to biodiesel can reach more than 90%; in the later stage of catalysis process by immobilized lipase, by introducing an online dehydration during the whole process or part of the reaction process, the yield of biodiesel can exceed 98%, and the acid value of the product can be less than 0.5 mg KOH per gram of oil. The method thus has good economic and environmental benefits.

## Claims

### Claim 1

A method for preparing biodiesel, wherein said method comprises steps of:
(1) adding oil and fat, short chain alcohol, water, and liquid lipase into a single-stage or multi-stage reactor for conducting a reaction, then separating the reaction liquid into a heavy phase and a light phase; recovering and reusing the liquid lipase in the heavy phase, and using the light phase for subsequent conversion by immobilized lipase;
(2) flowing the light phase obtained in step (1) into a single-stage or multi-stage reactor containing immobilized lipase, and adding short chain alcohol for conducting a reaction; wherein an online dehydration is carried out during the whole reaction or part of the reaction.

### Claim 2 (depends on 1)

The method according to claim 1, wherein said method comprises steps of:
(1) adding oil and fat, short chain alcohol of 4-8 times the mole of the oil and fat, 2%-20% of water based on the mass of oil and fat, and 200-2000 standard active units of liquid lipase per gram of oil and fat into the single-stage or multi-stage reactor; maintaining the temperature at 30-55° C.; and conducting the reaction for 3-8 hours;
(2) after the reaction, stratifying the liquid by centrifugation or standing, separating and recovering the enzyme protein in the heavy phase using a membrane, and using the light phase for subsequent conversion by immobilized lipase;
(3) reflowing the light phase obtained in step (2) and short chain alcohol of 1-3 times the mole of the oil and fat into single-stage or multi-stage reactor containing 200-1000 standard active units of immobilized lipase per gram of the mass of oil and fat; maintaining the temperature at 20-55° C.; conducting the reaction for 3-10 hours; wherein an online dehydration with a membrane or a molecular sieve is carried out during the whole reaction or part of the reaction.

### Claim 3 (depends on 2)

The method according to claim 2, wherein the membrane used for separating and recovering the enzyme protein in step (2) is a metal membrane, an organic membrane, an inorganic membrane, or a ceramic membrane.

### Claim 4 (depends on 2)

The method according to claim 2, wherein the membrane used for the online dehydration in step (3) is an organic membrane, an inorganic membrane, or a ceramic membrane; and wherein the molecular sieve used for the online dehydration is a 3 Å or 4 Å molecular sieve.

### Claim 5 (depends on 1)

The method according to claim 1, wherein the lipase is derived from one or more of Candida antarctica, Thermomyces lanuginosus, Aspergillus niger, Aspergillus oryzae, Rhizomucor miehei, and Rhizopus oryzae.

### Claim 6 (depends on 1)

The method according to claim 1, wherein the short chain alcohol is methanol, ethanol, propanol, or butanol.

### Claim 7 (depends on 1)

The method according to claim 1, wherein the short chain alcohol is evenly or unevenly fed from the beginning of the reaction, and the feeding is finished in 3-10 hours.

### Claim 8 (depends on 1)

The method according to claim 1, wherein the oil and fat is biological oil and fat, including vegetable oil, animal fat, or microbial oil.

### Claim 9 (depends on 8)

The method according to claim 8, wherein the vegetable oil is castor oil, palm oil, colza oil, soybean oil, peanut oil, corn oil, cottonseed oil, rice bran oil, Jatropha oil, yellow horn oil, or Jatropha curcas L. oil; the animal fat is fish oil, tallow, lard, or mutton oil; and the microbial oil is yeast oil or microalgae oil.

### Claim 10 (depends on 1)

The method according to claim 1, wherein the oil and fat includes waste cooking oil, or the oil and fat refining waste.