NL8200650A - Process for processing by-products of the alkaline deacidification of oils and fats. - Google Patents

Description

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Unilever N.V. Rotterdam \

Short content: Process for processing by-products of the alkaline deacidification of oils and fats.

The invention relates to a method for processing by-products of the alkaline deacidification of fatty oils, fats and mineral oils.

It is known that fatty oils and fats and mineral oils contain oxygen-containing compounds, in particular organic acids. For example, fatty oils contain e.g. the so-called free fatty acids are created by hydrolysis of the triglycerides.

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Triglycerides are valuable raw materials. The crude or incompletely refined oils and fats contain, in addition to the triglycerides, small amounts of other ingredients such as free fatty acids, dyes, sugars, sterol glycosides, waxes, partial glycerides, proteins, phosphatides and metals.

It is traditionally customary to remove the free fatty acids by the action of alkalis, in particular of a solution of sodium hydroxide in water, whereby they are converted into water-soluble salts (soaps) and all such of the oil or fat be separated. Many of the above substances are also removed. The by-product formed herein is usually referred to as the soapstock.

The soapstock is processed in different ways. It can be disposed of as such. Also, after acidification, the fatty acids, e.g. with sulfuric acid, released and worked up.

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These methods give rise to environmental concerns. Drain as such changes the pH of the surface water into which it is discharged. The products after isolation of the fatty acids still contain many organic substances and electrolytes, which on discharge, in addition to adversely affecting the pH, also reduce the oxygen content of the surface water (increase in b.o.d.).

It is clear that environmental law in hand 10 can mandate industry to take roads other than discharge.

It is of course possible to use a biological pre-purification, but this is an expensive method.

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It has now been found that: de_; soapstock can be processed into non-objectionable products by incineration. The organic substances are completely burned to water and carbon dioxide by the action of oxygen, whereby carbonate and small amounts of other salts are also formed.

If necessary, the soapstock is first evaporated to a process acceptable concentration, e.g. up to a content of 50% of total fatty matter.

The combustion is carried out with an excess of air or oxygen and at a temperature between 600 and 900 eC, preferably at 800 eC, so that the organic material burns completely.

The water present in the soapstock evaporates and is discharged as water vapor with the exhaust gases. The carbonate formed (when sodium hydroxide is used in the deacidification, soda is formed during the combustion) is removed as ash.

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Combustion preferably takes place in a fluidised bed furnace, the bed material of which is chosen such that neither the sockstock nor the substances formed, such as the carbonate, cause sintering nor melting to occur. A suitable material is titanium dioxide, but other materials can also be used.

The bed material and the solid combustion products formed can be entrained with the combustion gases and separated outside the oven.

Preferably, however, the particle size and density of the fluidized bed material is chosen such that after combustion a separation is effected by the rate of the combustion gases which entrains the solid combustion products and leaves the bed material.

The feed rate of the air or oxygen and that of the material to be burned are adjusted so that the temperature over the fluidized bed is fairly homogeneous, that only little carbon monoxide is formed and the content of nitrogen oxides is kept limited. 1 2 3 4 5 6 8 200 650

The 2 exhaust gases loaded with the formed solid combustion products can be cooled in an effective heat exchanging system, the exhaust heat can be used to generate steam and / or to preheat the feed gases.

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The solid combustion products are separated from the combustion gases in a filter system and can be removed in the usual manner without raising environmental concerns.

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EXAMPLE

Crude fish oil is deacidified in a known manner by treatment with a solution of sodium hydroxide in water. The resulting soap stock was evaporated to contain 50% total fatty matter.

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This soapstock is incinerated in a fluidized bed furnace containing bed material consisting of titanium dioxide with an average particle size of 1 mm.

The fluidized bed oven is brought to a temperature of 800 ° C by preheated air.

The soap stock is then introduced into the fluidized bed, the amounts of air and soap stock being chosen such that on the one hand the organic material is completely burned, on the other hand the temperature in the part where the combustion takes place remains at about 800 ° C.

The combustion gases charged with the soda particles are discharged at the top of the oven (the bed material remains in the oven) and are passed through a so-called waste gas boiler, in which the exchanged heat converts water into steam, which is used elsewhere in the company.

The cooled gases are separated from the entrained soda particles in a conventional fly ash filter system.

The combustion gases consisting mainly of water vapor and carbon dioxide are discharged into the atmosphere through a chimney and the soda is collected.

The soda obtained is free from organic material and can be used for all kinds of purposes.

8200650

Claims (7)

1. Process for the processing of by-products obtained from the alkaline deacidification of fatty oils, yets and mineral oils, characterized in that the by-products, if necessary after evaporation, are subjected to a high temperature in the presence of air or oxygen, whereby the organic substances are converted into water and carbon dioxide, carbonate and small amounts of other salts. Method according to claim 1, characterized in that the combustion is carried out at a temperature of 600-900 ° C. 3. Method according to claims 1-2, characterized in that the combustion is carried out at about 800 ° C. 4 A 529 (R) 4. Method according to claims 1-3, characterized in that the combustion takes place in a fluidised bed furnace. 4 A 529 HR) / Method according to claim 4, characterized in that titanium dioxide is used for the fluidized bed material. 25 A method according to claims 4-5, characterized in that the particle size of the fluidized bed material is chosen such that the solid combustion products formed are blown out of the fluidized bed 30 by the combustion gases, then cooled, and then from the spent gases in a filter system must be separated. 8200650 Method according to claims 1-6, characterized in that the conversion products are cooled in a heat exchanger, wherein the removed heat is used for generating steam. 8200650