DE102009006923A1 - Removing sterol glycoside containing precipitates in production of fatty acid alkyl esters comprises mixing fats or oils, alkyl and catalyst, and separating mixture into light phase, ester rich phase and heavy, glycerin rich phase - Google Patents

Abstract

Removing sterol glycoside containing precipitates in the production of fatty acid alkyl esters in a production device, comprises mixing at least one fats or oils, alkyl and a catalyst in a mixing reactor, and separating the resulting mixture into light phase, ester rich phase and a heavy, glycerin rich phase by a separator, where: subsequently fatty acid alkyl ester is separated from the light, ester riche phase, and an agent containing organic nitrogen base, cyclic organic oxo compound and/or organic acid anhydride, is introduced into the production device. Removing sterol glycoside containing precipitates in the production of fatty acid alkyl esters by transesterification of fats or oils with alkyl alcohols in a production device, comprises mixing at least one fats or oils, alkyl and a catalyst in a mixing reactor, and separating the resulting mixture to light phase, ester rich phase and a heavy, glycerin rich phase by a separator, where: subsequently fatty acid alkyl ester is separated from the light, ester riche phase, and an agent containing organic nitrogen base, cyclic organic oxo compound and/or organic acid anhydride, is introduced into the production device. Independent claims are included for: (1) the agent for removing sterol glycoside containing precipitates; and (2) a device for producing fatty acid alkyl ester by transesterification of fats or oils with alkyl alcohol comprising a conversion zone (1, 4), a mixing reactor (2, 5) to mix fats or oils with the alkyl alcohol and catalyst, and a separator (3, 6) for separating the mixture into light, ester rich phase and a heavy, glycerin rich phase, a wash column (21) for separating the fatty acid alkyl ester and a drying zone (25) for drying fatty acid alkyl ester and/or optionally a filter unit (26), where at least a pipeline (27-30) is used for the supplying the agent into the wash column, drying zone, filter unit, a product tank (35) and/or between pipelines (24).

Description

The The invention relates to the removal of sterol glycosides Precipitates in the production of fatty acid alkyl esters by transesterification of fats and oils with alkyl alcohols in a production plant with at least one implementation stage consisting of a mixing reactor in which the fats and oils be mixed with the alkyl alcohols and a catalyst, and a separator in which the resulting mixture in a light, rich in esters Phase and a heavy, glycerol-rich phase is separated, wherein then from the light, ester-rich phase fatty acid alkyl esters separated.

Processes for the conversion of vegetable oils or animal fats to fuels by transesterification of the glycerol-bound fatty acids (triglycerides) with short-chain alcohols, such as, for example, methanol, are known. So will in the FR 996 608 the transesterification of palm oil with methanol or ethanol in the presence of a strong inorganic acid, such as hydrochloric acid or sulfuric acid, described as a catalyst for the purpose of fuel production.

The FR 2 560 210 describes the preparation of a methyl, ethyl, propyl or butyl ester of fatty acids from vegetable oils or animal fats and the use of the product as a diesel fuel. The light, non-polar, fatty acid ester-containing phase is separated from the heavy, polar, glycerol-containing phase. To improve the combustion properties, the product phase is treated with an adsorbent.

In the in the WO 87/07632 A1 described method, the production of biofuel starting from triglycerides in a two-stage process, where first a substance containing crude triglycerides reacts with an alkanol in the presence of a catalyst to convert the fatty acids contained in the crude triglycerides containing substance into their alkyl esters. The product of the first process step is washed with an aqueous detergent to form a two-phase organic system, wherein the catalyst is transferred from the reaction mixture to the aqueous phase.

A modern process for the production of fatty acid methyl ester or fatty acid ethyl ester and glycerol by transesterification of fats or oils is in EP 0 532 767 B1 described. In this process, the reaction of the oil or fat with methanol or ethanol and an alkaline catalyst in the liquid phase to the products fatty acid methyl ester or fatty acid ethyl ester and glycerol, which are obtained separately and are value products of the process. The process employs at least two reaction stages, each reaction stage containing a mixing reactor and a separator for separating a light, high-ester phase and a heavy, glycerol-rich phase. The heavy phase recovered in the separator of the second to last reaction stage is at least partially recycled to the mixing reactor of the first reaction stage. The ester products of the process after processing and purification as a so-called biodiesel represent a marketable product.

It It is known that the use of certain vegetable oils in the conversion to fatty acid methyl ester or fatty acid ethyl ester (Biodiesel) to Feststoffausfällungen in the manufacturing process or during subsequent storage of the product at cold ambient temperatures can lead. This behavior is pronounced, for example. to observe when using soybean oil or palm oil. In the processing of such oils is therefore an increased Maintenance required for the production plant. In addition, the availability and thus the productivity The production facility is restricted as it is for maintenance and Elimination of Feststoffausfällungen except Operation must be taken. The precipitates can by mechanical processes, such as filtration or centrifugation, be separated.

Responsible for the formation of the precipitates are so-called sterol glycosides (SG), which are widespread herbal ingredients that result from the combination of a sugar (glucose) with a phytosterol. Phytosterols are plant hormones and are components of plant cell membranes. Known representatives are stigmasterol or campesterol, whose structural forms in 1a respectively. 1b are shown. In addition, on the US 4 112 218 directed.

In the WO 2007/076163 A2 describes the addition of an adsorbent or filtration aid to separate the solid precipitates from biodiesel and its subsequent removal by filtration or centrifugation. However, this treatment is possible in a simple manner only for the finished biodiesel product. The elimination of already occurred in the production precipitates can be done by this measure only at great expense. From the WO 2007/076163 A2 It is also known to bring biodiesel into contact with a component which can remove sterol glycosides from the biodiesel. As components for this are adsorbents, filter media, boric acid, soaps, sucrose, sugar, glucose, sodium chloride, citric acid, magnesium silicate, clay, silica, lecithin, proteins, carbon, cellulose, Lösun proposed with boric acid or silica hydrogel. However, the proposed components are only insufficiently capable of solubilizing and eliminating precipitates caused by sterol glycosides. In addition, the above-described problem of precipitations in the production plant can not be eliminated by the treatment of the end product biodiesel.

Preparative methods are known for converting sterol glycosides into acetylated products by reaction with acetic anhydride, which have good solubility in non-polar organic solvents, such as chloroform and cyclohexane ( US 4,235,992 ).

To Braus et al. ("Isolation and Identification of a Sterol Glucoside from Whiskey" in Agricultural and Food Industry Vol. 5 No. 6 (1957) p. 458) For example, pure sterol glycosides are soluble in pyridine and other polar solvents. There are no statements about the solubility of sterol glycosides in the presence of fatty acid methyl esters or biodiesel.

task The present invention is in the production of biodiesel occurring precipitates based on sterol glycosides to remove from the production plant.

These The object is achieved with the invention essentially by that the production plant is supplied with a means which organic nitrogen bases, cyclic organic oxo compounds and / or organic acid anhydrides. By the addition of such a cleaning agent will be in the production plant for biodiesel production occurred precipitates again brought into solution and can be removed from the plant.

When Particularly suitable organic nitrogen base has proven pyridine. A particularly suitable cyclic oxo compound is dioxane or tetrahydrofuran, while acetic anhydride (acetic anhydride) has proved to be a suitable organic acid anhydride. Of course, it is within the scope of the present Invention, also mixtures of these components in the detergent to use.

The Cleaning agent is preferably introduced in liquid form, for easy mixing with the intermediates in the To allow production of fatty acid alkyl esters. This can be done according to the invention in that the agent is added to the intermediate (crude ester). alternative or in addition, however, it is also possible that the agent via separate supply lines to later Process steps is introduced directly into the production plant.

Preferably the agent becomes concentrated or diluted introduced into the production plant, the concentration according to the Requirements of the plant can be adjusted and the addition can be continuous or discontinuous.

Becomes, as in a preferred embodiment of the invention provided, the cleaning agent under pressure, with pulsating current and / or introduced into the production plant at elevated temperature, so cleaning is similar to a high-pressure cleaner with particularly high efficiency.

at The production of biodiesel is the fatty acid alkyl esters after separation in the separator, preferably in a wash column separated from the light, ester-rich phase and then dried, filtered and stored. In development of the invention the cleaning agent in the wash column, the drying stage, the filter unit, product tanks or in between Pipes introduced because these parts of the plant in terms of Formation of precipitates are particularly sensitive. The Sterolglycosidsedimente preferably store in the wash column and the heat exchanger from the dryer, so that there Addition of the cleaning agent is particularly effective.

Become organic nitrogen bases or cyclic organic oxo compounds, in particular pyridine, dioxane and / or tetrahydrofuran, as a cleaning agent used, it is preferably from the sterol glycoside Biodieselgemisch distilled off and can then be reused.

Becomes Acetic anhydride or other organic acid anhydride used as a cleaning agent, so that can be dissolved Sterol glycoside sediment according to the invention with biodiesel be diluted. After distillative removal of the low boilers may be the modified or acetylated sterol glycosides remain in the final product without compromising the quality of the final product is impaired.

The The invention also encompasses a sterol glycoside removal agent containing precipitates in the production of fatty acid alkyl esters Transesterification of fats and oils with alkyl alcohols, wherein the agent organic nitrogen bases, such as pyridine, cyclic oxo compounds, such as dioxane or tetrahydrofuran, and / or organic acid anhydrides, such as acetic anhydride.

According to one Particularly preferred embodiment of the invention is in biodiesel dissolved acetic anhydride used as a cleaning agent.

A plant according to the invention for the manufacture Development of fatty acid alkyl esters by transesterification of fats and oils with alkyl alcohols, which is suitable for carrying out the method described above, comprises at least one reaction stage with a mixing reactor for mixing the fats and oils with the alkyl alcohols and a catalyst and a separator in which the mixture in a light, ester-rich phase and a heavy, glycerol-rich phase is separated, a wash column for the separation of fatty acid alkyl esters from the light, ester-rich phase, a drying stage for Trock tion of the fatty acid alkyl esters, optionally a filter unit and at least one supply line for the supply of the detergent described above in the wash column, the drying stage, the filter unit, a product tank and / or provided therebetween pipelines.

Around to separate the detergent from the fatty acid alkyl ester, is according to the invention according to the washing column, the Drying stage, the filter unit and / or a product tank a corresponding separating device, in particular a distillation or a rectification column provided.

Further developments, Advantages and applications of the invention result also from the following description of exemplary embodiments and the drawing. All are described and / or illustrated illustrated features alone or in any combination the subject of the invention, regardless of its summary in the claims or their dependency.

It demonstrate:

1a the structural formula of stigmasterol as an example of a sterol glycoside,

1b the structural formula of campesterol as an example of a sterol glycoside and

2 schematically a plant for carrying out the method according to the invention.

In the 2 schematically illustrated plant for the production of fatty acid alkyl esters by transesterification of fats and oils with alkyl alcohols has two reaction steps. In the illustrated embodiment, methanol is used as the alcohol, but the process can be carried out in the same way with ethanol to produce ethyl ester.

The first implementation stage 1 has a mixing reactor 2 and a subsequent gravitational separator 3 on. Accordingly, also the second implementation stage 4 a mixed reactor 5 and a gravity separator 6 on. The oil or fat to be treated flows through a pipe 7 in the mixing reactor 2 , The reactor 2 one leads further by a line 8th largely anhydrous methanol and a catalyst and through the line 9 heavy, glycerol-containing phase from the second reaction stage 4 to. The catalyst is passed through the line 10 introduced and mixed with the methanol. In the reactor 2 Intensive mixing takes place with the aid of at least one stirring device 11 , The mixing reactor 2 may comprise a plurality of cascaded mixing chambers in a known manner.

The temperatures in the mixing reactor 2 are usually in the range of 40 ° C to the boiling point of the mixture. When working at atmospheric pressure, temperatures up to 68 ° C. have proven to be expedient. At higher pressures, temperatures up to 90 ° C make sense. Between the mixing reactor 2 and the separator 3 a cooling not shown here may be provided to the separation in the separator 3 to facilitate. As a gravity separator is preferably used fiber bed, known per se and, for example. In "Filtration and Separation", September / October 1990, pages 360 to 363 are described.

In the separator 3 Draw a light, methyl ester-rich phase, which is passed through the line 12 to the mixing reactor 5 the second implementation stage 4 leads. The in the line 13 withdrawn heavy, glycerol-rich phase is together with the wash water in a manifold 23 from a wash column 21 after pH adjustment to 1.5-2.0 for rectification of a column 14 given up. In the known rectification column 14 you win over head largely anhydrous methanol, which is in the line 15 withdraws and the methanol of the line 8th admits. From the bottom of the column 14 you go through a pipe 16 a glycerol / water / fatty substance mixture which is fed to a gravitational separator at temperatures of 50 ° C to 90 ° C for the separation of the fatty acid and methyl ester constituents dispersed in the glycerol water. As a light phase, the fatty substance forms ("Fatty Matter") and is withdrawn continuously. The heavy water-glycerol phase becomes an evaporator 17 fed and the water separated. The crude glycerol with a water content of 2 to max. 10% is over a line 18 fed to a cleaning, not shown.

The second implementation stage 4 one leads next to the light, methyl ester-rich phase from the separator 3 over a line 19 a mixture of methanol and catalyst. Before entering the mixing reactor 5 can the temperature of the methyl ester-rich phase of the line 12 lowered or raised in a heat exchanger, not shown. In the mixed reactor 5 in which again intensive mixing takes place, the temperature is about the same as in the mixing reactor 2 , In front of the separator 6 In turn, a cooling, not shown, may be provided.

The heavy, glycerol-rich phase, in the separator 6 accumulates, is through the line 9 to the mixing reactor 2 recycled. The light, methyl ester-rich phase (crude ester) passes through the line 20 to an intensive mixer 32 in which the alkaline raw ester for neutralization with over a line 31 mixed dilute hydrochloric acid is mixed, so that in the subsequent separator 33 the separation into a light, methyl ester-rich phase and a heavy, sodium chloride-containing acidic methanol-water phase takes place. The heavy, acidic methanol-water phase is piped over 34 the leader 23 fed. The light, methyl ester-rich phase is passed through the pipeline 20 a wash column 21 fed, which one over the line 22 that in the evaporator 17 supplied water feeds. The water absorbs the water-soluble substances, especially methanol, glycerol, salts and the excess salts of the upstream catalyst neutralization. The aqueous phase, which contains methanol and glycerol and is virtually free of methyl ester, passes through the manifold 23 as already described above after admixing the glycerol-rich phase from the line 13 the rectification column 14 given up.

On the other hand, from the wash column 21 over the line 24 Deducted fatty acid methyl ester, which can be used as biodiesel. Since the water content is still too high, it must by heating in a heat exchanger, not shown, and subsequent drying, for example. Vacuum drying, in a drying step 25 be reduced. This gives a largely dried (anhydrous) product with a biodiesel specification corresponding water content of not more than 0.05%, which subsequently in a filter unit 26 freed of impurities and in a product tank 35 is stored.

Around in the production of fatty acid alkyl esters described above To remove precipitates based on sterol glycosides, the production plant is supplied with a cleaning agent, the organic nitrogen bases, such as pyridine, cyclic organic Oxo compounds, such as dioxane or tetrahydrofuran, and / or organic Acid anhydrides, such as acetic anhydride. According to one particularly preferred embodiment contains the cleaning agent acetic anhydride dissolved in biodiesel.

The cleaning agent is introduced into the production plant in liquid form, preferably via separate supply lines 27 to 30 . 36 in the wash column 21 , the drying stage 25 , the filter units behind 26 , Product tanks 35 or in between planned pipelines 24 is introduced.

By the addition of the cleaning agent precipitates occurred in the system are brought back into solution and thus removed from the system. Since the cleaning agent can affect the biodiesel quality, the cleaning should be carried out in the shutdown process stages. This is especially true for the wash column 21 , Therefore, the cleaning of the wash column should 21 if necessary, also take preventative measures during scheduled system shutdowns. Heat exchangers in dryers or filter units are often run in parallel operation, so it is therefore possible to clean the disconnected modules during operation.

The Detergent may be under pressure, with pulsating current and / or with elevated temperature via corresponding rinsing nozzles be introduced into the production plant to similar a high-pressure cleaner to achieve a particularly high impact.

If dioxane, tetrahydrofuran or pyridine is used as the cleaning agent, it may be obtained by distillation in a separator 37 separated from the sterol glycoside biodiesel mixture and reused. The remaining sterol glycoside biodiesel sludge is a high quality fuel and can be used energetically.

When acetic anhydride or other organic acid anhydride is used, the sterol glycosides are chemically converted to a soluble product. After distillative removal of the low boilers in the separator 37 For example, the modified or acetylated sterol glycosides can be dissolved in biodiesel and then admixed to the end product without impairing the quality of the end product. In this case, the methyl ester content should be at least 96.5% in order to comply with the biodiesel specification.

If the cleaning agent should be mixed with raw biodiesel in advance should the concentration of the detergent in the mixture at least 1%. The cleaning agent can also be concentrated be used.

After cleaning and draining the cleaning agent, the corresponding unit should be rinsed with water and biodiesel to remove residual amounts of cleaning agent. The drained cleaning agent may optionally be used several times after filtration of precipitations caused by concentration. The operating temperature should be chosen so that it is below the boiling point of the Reini is located. The exposure time is between 15 and 180 minutes and depends on the degree of contamination of the unit, the concentration used and the temperature of the cleaning agent.

1

first conversion stage

2

mixing reactor

3

separators

4

second conversion stage

5

mixing reactor

6

separators

7

management

8th

management

9

management

10

management

11

agitator

12

management

13

management

14

column

15

management

16

management

17

Evaporator

18

management

19

management

20

management

21

washing column

22

management

23

management

24

management

25

drying stage

26

filter unit

27-30

supply lines

31

hydrochloric acid line

32

mixing device

33

separator

34

management

35

Reservoir

36

supply line

37

separator

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• FR 996608 [0002]
• - FR 2560210 [0003]
• WO 87/07632 A1 [0004]
• - EP 0532767 B1 [0005]
• - US 4112218 [0007]
• - WO 2007/076163 A2 [0008, 0008]
• - US 4235992 [0009]

Cited non-patent literature

• Braus et al. ("Isolation and Identification of a Sterol Glucosides from Whiskey" in Agricultural and Food Industry Vol. 5 No. 6 (1957) p. 458) [0010]
• - "Filtration and Separation", September / October 1990, pages 360 to 363 [0031]

Claims (15)

A process for the removal of sterol glycoside-containing precipitates in the production of fatty acid alkyl esters by transesterification of fats or oils with alkyl alcohols in a production plant, which is mixed in at least one reaction stage in a mixing reactor, the fats or oils and the alkyl alcohols and a catalyst and in a separator, the obtained Separating mixture into a light, ester-rich phase and a heavy, glycerol-rich phase and subsequently separating fatty acid alkyl esters from the light, ester-rich phase, characterized in that a means comprising organic nitrogen bases, cyclic organic oxo compounds and / or organic acid anhydrides is fed to the production plant contains. Method according to claim 1, characterized in that that the agent contains a component selected from the group consisting of pyridine, dioxane, tetrahydrofuran, acetic anhydride or Mixtures thereof is selected. Method according to claim 1 or 2, characterized that the agent is introduced in liquid form. Method according to one of the preceding claims, characterized in that the means by separate supply lines is introduced into the production plant. Method according to one of the preceding claims, characterized in that the agent is concentrated or diluted Form is introduced into the production plant. Method according to one of the preceding claims, characterized in that the means under pressure, with pulsating Electricity and / or elevated temperature in the production plant is introduced. Method according to one of the preceding claims, wherein the agent in particular organic nitrogen bases and / or contains cyclic organic oxo compounds, characterized in that the agent by distillation from the sterol glycoside biodiesel mixture is separated. Method according to one of claims 1 to 7, wherein the agent is in particular an organic acid anhydride contains, characterized in that in solution diluted sterol glycoside sediment diluted with biodiesel and the low boilers containing are distilled off. Method according to one of the preceding claims, wherein the fatty acid alkyl esters in a wash column separated from the light, ester-rich phase and then be dried and optionally filtered, characterized in that the agent in the wash column, the drying stage, the filter unit, possibly provided product tanks and / or provided in between Piping is introduced. Agent for removing sterol glycosides Precipitates in the production of fatty acid alkyl esters by transesterification of fats and oils with alkyl alcohols, in particular in a method according to one of the preceding claims, characterized in that the agent comprises organic nitrogen bases, contains cyclic organic oxo compounds and / or organic acid anhydrides. Agent according to claim 10, characterized in that that the agent contains a component selected from the group consisting of pyridine, dioxane, tetrahydrofuran, acetic anhydride or Mixtures thereof is selected. Agent according to claim 10 or 11, characterized that the agent contains dissolved in biodiesel acetic anhydride. Plant for the preparation of fatty acid alkyl esters by transesterification of fats or oils with alkyl alcohols, with at least one reaction stage ( 1 . 4 ), which is a mixed reactor ( 2 . 5 ) for mixing the fats or oils with the alkyl alcohols and a catalyst, and a separator ( 3 . 6 ), in which the mixture is separated into a light, ester-rich phase and a heavy, glycerol-rich phase, a wash column ( 21 ) for the separation of fatty acid alkyl esters from the light, ester-rich phase and a drying step ( 25 ) for drying the fatty acid alkyl esters and optionally a filter unit ( 26 ), characterized by at least one supply line ( 27 - 30 ) for the supply of an agent according to any one of claims 10 to 12 in the wash column ( 21 ), the drying stage ( 25 ), the filter unit ( 26 ), a product tank ( 35 ) and / or pipes provided therebetween ( 24 ). Plant according to claim 13, characterized by a separating device ( 37 ) for separating the detergent from the fatty acid alkyl ester. Use of an agent according to one of the claims 10 to 12 for the removal of sterol glycoside-containing precipitates in the production of fatty acid alkyl esters from fats or oils.