DE102008051348A1 - Process for the production of fuel, in particular diesel fuel - Google Patents

Abstract

The invention relates to a process for the production of fuel, in particular diesel fuel, from vegetable or animal oils or fats, in which, with the addition of an alcohol and a catalyst, transesterification of the fatty acids esterified by glycerine, contained in the oils or fats and the reaction product of sedimentation is subjected, in which transesterified oil or fat settles from the remaining components of the reaction product. According to the invention, an alkaline catalyst is used and the reaction is stopped by adding water at an appropriate time.

Description

The The invention relates to a process for the preparation of, in particular used as diesel fuel, fuel from vegetable or animal oils or fats, in which with the addition of an alcohol and a catalyst a transesterification of the esterified by glycerol, in the oils or Fats contain fatty acids takes place and the reaction product subjected to sedimentation becomes, at which the transesterified oil or fat of the remaining components of the reaction product settles.

One such process for the production of fuels, in particular Fuels, is known by use. From oil or fat waste, however also from fresh vegetable oil, Be suitable for combustion in engines or heaters suitable fuels generated. In commercial kitchens and Households and fat waste can be done in this way instead of causing high disposal costs, usefully continue to use.

Of the Invention is the object of this known method continue to develop, with less effort higher quality fuels to be able to produce.

The solving this task Method according to the invention is characterized in that an alkaline Catalyst used and the transesterification by addition of water is stopped.

By the addition according to the invention of water the reaction will end at an appropriate time, resulting in beneficial to the quality the reaction product produced and the subsequent sedimentation effect. In particular, saponification and emulsification can be prevented.

In the settled, transesterified oil contained alcohol and / or catalyst residues can be removed later.

In Advantageous embodiment of the invention is the oil or fat deprived of water and optionally solid before transesterification. By the prior withdrawal of water is an unfavorable course of the reaction, especially saponification and the formation of emulsions prevented and the separation of the esters from the glycerol assured.

Preferably if the transesterification is stopped after a given reaction time, preferably during This reaction time a predetermined temperature is maintained. The reaction time and also the temperature may vary from the composition of the transesterified oils or fat dependent be.

When Starting product is preferably a mixture of different oils or / and Used fats. Can be mixed z. B. Waste oils with fresh Vegetable oils.

Preferably the transesterification takes place by addition of a short-chain alcohol, in particular by adding methanol, ethanol or / and propanol. By using such alcohols, a viscosity such as for fuels for Internal combustion engines is required to achieve.

Of the Catalyst can be added before the addition of the alcohol in the alcohol, preferably while stirring, Completely solved and the oil or fat with the solution be offset.

In a preferred embodiment The invention potassium hydroxide is used as a catalyst with methanol as Alcohol dissolved to form methoxide.

The with the alcohol and catalyst mixed oil mixture is, preferably while stirring, over one predetermined period, preferably 45 minutes, on a given Temperature, preferably maintained between 50 ° and 65 ° C, in particular 55 ° C. and then the water is added to stop the reaction. On one Liter of oil or fat can z. B. 150 ml of methanol, 5.5 g of potassium hydroxide and 50 ml of water omitted.

Preferably the sedimentation takes place at room temperature for a given period, z. For 15 to 20 minutes.

The The invention will be further explained with reference to an embodiment. It show in a schematic representation:

1 a plant for pretreatment with diesel fuel vegetable oils or fats to be processed,

2 a plant for transesterification by the plant of 1 pretreated oils or fats, and

3 a plant for the aftertreatment by the plant of 2 produced diesel fuel.

An in 1 shown container 1 , which contains waste cooking oil, can in a thirty such containers 1 to be preheated to the receiving facility. In the preheater (not shown), the edible oil is heated to a temperature between 50 ° and 60 ° C. The containers 1 with the heated cooking oil are placed in a coarse filter 2 emptied into it and the empty containers 1 subjected to purification to recover residual oil adhered thereto. In the coarse filter 2 a deposition of solid particles with dimensions> 5 mm.

From the coarse filter 2 The coarse-cleaned oil then enters a fine filter 3 , which filters out solid suspended particles with dimensions> 1 mm.

That in the fine filter 3 treated waste feed oil is then a heated water separator 4 fed, which keeps the oil at a temperature of 50 ° C.

The now dried, still suspended particles with dimensions> 1 mm containing oil is then a separator 5 fed, which filters out residual sediment particles with dimensions> 50 microns.

The dried and purified waste feed oil finally enters a heated storage tank 6 ,

The cooking oil in the storage tank 6 leaves one in there 2 shown mixing container 7 respectively. In the mixing container 7 For example, oil may be charged from at least one other source, e.g. B. from a reservoir, the fresh vegetable oil, z. B. rapeseed oil contains. The mixing container is heated. The mixed oil is kept at a temperature of 65 ° C.

At the mixing container 7 facilities are provided which allow a determination of the composition of the oil mixture. In particular, a titration can be carried out in which preferably the pH is determined.

From the mixing container 7 the oil mixture enters a reactor 8th that with storage containers 9 to 11 connected is.

The reservoir 9 and 10 contain methoxide, which is formed in solution of potassium hydroxide, which serves as an alkaline catalyst in methanol. In the container 9 and 10 Methoxide is contained in different ratios of potassium hydroxide and methanol. The storage tank 11 contains water.

The in the reactor 8th filled oil mixture is depending on the result of the above-mentioned titration methoxide from the reservoir 9 or the reservoir 10 added and thus triggered a transesterification, in which the esterifying the fatty acids of the oil mixture glycerol is exchanged for methanol. After a predetermined reaction time, which may also be dependent on the titration result, the transesterification is stopped by removing from the reservoir 11 in the reactor 8th Water is entered. The alkaline transesterification process then comes to a standstill immediately.

That in the reactor 8th resulting reaction mixture is then in a sedimentation tank 12 pumped, in which the interesterified oil separates from glycerine and water. The transesterified oil settles above, glycerin and water settle down. In the exemplary embodiment shown, one liter of oil mixture accounts for 150 ml of methanol and 50 ml of added water. The methoxide in the tank 9 contains per 150 ml of methanol 5.5 g of potassium hydroxide.

The transesterified oil can be used as fuel and in particular, after being treated again was used as diesel fuel.

In an in 3 shown aftertreatment plant is carried out a laundry of the top layer of the sedimentation 12 pumped out, transesterified oil and a subsequent drying.

A wash tank 13 includes a spraying device 14 for spraying water onto the surface of the sedimentation tank 12 in the wash tank 13 transferred oil. The wash tank 13 also has a device 15 for generating in the oil rising air bubbles. The spraying is carried out with water at a temperature of 40 ° C, the spray pressure is so low that no water penetrates into the surface. In the illustrated embodiment, the spraying time is one hour, wherein 100 liters are sprayed. During spraying, at the same time, the device designed as a pyramidal aerator is used 15 Compressed air bubbles generated at a pressure of two bar, the air temperature is 40 ° C. After a rest period of z. B. two hours, the washing process is completed. The water on the surface of the oil has absorbed the impurities previously contained in the oil.

The washed oil becomes a heated drying container 16 with a vapor extraction device 17 fed. The drying is carried out at 65 ° to 75 ° C, the resulting water vapor is removed by suction.

After a visual check for clarity, a pH measurement and a conductivity measurement, the decision is made as to whether washing and drying were sufficient; if necessary, the oil is returned to the wash tank 13 or drying container 16 , If the tests or measurements fail satisfactorily, the dried oil becomes a filter 18 supplied, which again filter out particulate matter particles with dimensions> 50 microns, wherein in the relevant embodiment a backwash filter is used in a twin filter housing with differential pressure changeover.

The product thus treated is readily usable as heating oil. For the purpose of producing high quality diesel fuel, the post-treated oil becomes a mixer 19 which is supplied from a reservoir an oxidation inhibitor, in the embodiment shown butylhydroxitoluene.

That in the sedimentation tank 12 Deposited glycerol-water mixture can be separated in a glycerol separator in glycerol and impurities containing water, wherein the glycerol can be supplied to a further use.

The Impurities containing water can be reused process by filtering it and, if necessary, neutralizing it after a pH measurement becomes.

Claims (12)

A process for the production of fuel, in particular diesel fuel, from vegetable or animal oils or fats, wherein the addition of an alcohol and a catalyst, a transesterification of glycerol esterified, contained in the oils or fats fatty acids and the reaction product is subjected to sedimentation, in which the transesterified oil or fat settles from the remaining constituents of the reaction product, characterized in that an alkaline catalyst is used and the transesterification reaction is terminated by the addition of water. Method according to claim 1, characterized in that that from the deposited sedimentation oil or fat alcohol and / or catalyst residues be removed. Method according to claim 1 or 2, characterized that the oil or grease before the transesterification water and possibly solid is removed. Method according to one of claims 1 to 3, characterized that the reaction stopped after a given reaction time becomes. Method according to one of claims 1 to 4, characterized that as the starting product for the transesterification used a mixture of different oils and / or fats becomes. Method according to claim 4 or 5, characterized that the reaction time depends on the composition of the transesterified oil and / or Fat mixture is selected. Method according to one of claims 1 to 6, characterized that the transesterification by addition of a short-chain alcohol, in particular Addition of methanol, ethanol or / and propanol, takes place. Method according to one of claims 1 to 7, characterized in that the catalyst used is potassium hydroxide and / or sodium hydroxide becomes. Method according to one of claims 1 to 8, characterized the catalyst is added to the alcohol prior to the addition of the alcohol. Method according to one of claims 1 to 9, characterized that used as catalyst potassium hydroxide and in methanol Formation of methoxide dissolved becomes. Method according to one of claims 1 to 10, characterized in the transesterification, the oil or fat mixed with the alcohol and catalyst, preferably with stirring, over a designated Period, preferably 45 minutes, at a designated temperature, preferably between 50 ° and 65 ° C, in particular 55 ° C, held and then the water is added. Method according to one of claims 1 to 11, characterized that on a quart of oil or Fat as alcohol 150 ml methanol, as catalyst 5.5 g potassium hydroxide and 50 ml of water omitted.