# US 2014/0194634 A1 · Method for preparing high purity biodiesel

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- Number: US 2014/0194634 A1
- Document ID: US20140194634A1
- Status: Published application
- Kind: A1
- Application number: 14/237,888
- Filed: 2012-08-09
- Published: 2014-07-10
- Earliest claimed: 2011-08-10
- Assignees: Beijing Qingyanlihua Petroleum Chemistry Co., Ltd.
- Inventors: Xinuo Lu
- Web page: https://patentgrep.com/patent/US20140194634A1

## CPC

- C10L 1/02: essentially based on components consisting of carbon, hydrogen, and oxygen only
- C07C 67/03: by reacting an ester group with a hydroxy group
- C10L 1/026: {for compression ignition}
- C11B 13/00: Recovery of fats, fatty oils or fatty acids from waste materials
- C11C 1/10: by distillation
- C11C 3/003: {by esterification of fatty acids with alcohols (C11C3/02 takes precedence)}
- C11C 3/10: Ester interchange
- C07C 67/02: by interreacting ester groups, i.e. transesterification
- C07C 67/08: by reacting carboxylic acids or symmetrical anhydrides with the hydroxy or O-metal group of organic compounds
- Y02E 50/10: Biofuels, e.g. bio-diesel
- Y02W 30/74: Recovery of fats, fatty oils, fatty acids or other fatty substances, e.g. lanolin or 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
- C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C11B: PRODUCING, e.g. BY PRESSING RAW MATERIALS OR BY EXTRACTION FROM WASTE MATERIALS, REFINING OR PRESERVING FATS, FATTY SUBSTANCES, e.g. LANOLIN, FATTY OILS OR WAXES; ESSENTIAL OILS; PERFUMES (drying-oils C09F)
- 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
- Y02E: REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## Abstract

Disclosed is a method for preparing high purity biodiesel from crude oils. The method comprises the steps of: pre-treating the crude oil raw material to remove impurities; pre-esterifying the pre-treated crude oil raw material under the effect of a catalyst of concentrated sulfuric acid; and then carrying out an ester exchange reaction in the presence of an alkali catalyst; recycling methanol, and separating glycerol, so as to obtain a crude fatty acid methyl ester; and subjecting the obtained fatty acid methyl ester to purification, distillation and segmentation to obtain a high-purity fatty acid methyl ester.

## Claims

### Claim 1

A method for preparing biodiesel from crude oils, comprising:
1) providing crude oil raw material, and pre-treating the crude oil raw material to remove impurities;
2) adding the pre-treated raw material into a reaction kettle;
3) pre-esterification step: adding methanol and 0.1-2 wt % concentrated sulfuric acid by the weight of the pre-treated raw material into the reaction kettle, and maintaining at 70-100° C., preferably 70-80° C., for 30 min-2 h, wherein the weight ratio of methanol to the pre-treated raw material is (1:1)-(1:20);
4) esterification step of vapor phase: heating the above reaction system to 110-130° C., supplementing vapor phase methanol from the bottom of the reaction kettle under atmospheric pressure, reacting under the temperature until the acid value of liquid phase system is ≦2, and stopping supplementing methanol;
5) ester exchange step: cooling the reaction material obtained in the step 4) to below 70° C., adding mixture of potassium hydroxide and sodium hydroxide withequal weight ratio in the same reaction kettle to maintain pH of the reaction material in the reaction kettle at 8-9, and then reacting at 70-90° C., preferably 70-80° C., for 2-3 h;
6) recycling methanol, and separating glycerol via gravity settling, so as to obtain a crude fatty acid methyl ester; and
7) subjecting the crude fatty acid methyl ester obtained in the step 6) to purification and distillation to obtain biodiesel.

### Claim 2 (depends on 1)

The method according to claim 1, wherein the crude oil raw material is trench oil or acid oil.

### Claim 3 (depends on 1, 2)

The method according to claim 1 or 2, wherein the weight ratio of methanol to the pre-treated raw material in the step 3) is (1:15)-(1:4).

### Claim 4 (depends on 3)

The method according to claim 3, wherein the weight ratio of methanol to the pre-treated raw material in the step 3) is (1:11)-(1:6).

### Claim 5 (depends on 1, 2)

The method according to claim 1 or 2, wherein the distillation of crude fatty acid methyl ester in the step 7) is performed at the temperature of 220-260° C. under the pressure of (−0.090)-(−0.099) MPa, so as to obtain the biodiesel and plant pitch.

### Claim 6 (depends on 1, 2)

The method according to claim 1 or 2, wherein in the step 7), the crude fatty acid methyl ester is directly and continuously distilled and segmented into fraction products of four temperature intervals: a. ≦280° C.; b. 280-365° C.; c. 365-380° C.; and d. ≧380° C.

### Claim 7 (depends on 1, 2)

The method according to claim 1 or 2, wherein the recycling of methanol in the step 6) is performed via two steps: recycling at the temperature of 85-95° C. under atmospheric pressure and recycling at the temperature of 85-95° C. and vacuum.

### Claim 8 (depends on 1, 2)

The method according to claim 1 or 2, wherein the pre-treatment comprises water washing, dehydration in vacuum or the combination thereof.