DE1645834A1 - Process for recycling used bleaching earth from secondary refining of old oils - Google Patents

Description

Process for recycling used bleaching earth from secondary refining of waste oils When secondary or re-refining of waste oils is usually carried out in one Pre-distillation from the raw oil (rotor and @ aschinenaltöl) that read. cier and The volatile matter is separated off and the anhydrous residue with W - 4 vol 96% Sulfuric acid refined at room temperature. @an can also have more abortions and that Fractionate the distillate again and refine it; oh everyone because for themselves. at the sulfuric acid refining separates the acid resin, also called acid tar, as viscous liquid, which settles down in the separating container into the @onus and is dismissed. The acid resin contains reaction products of sulfuric acid with the additives and unsaturated oil parts and also the finely dispersed carbon black. in the "Sour oil" colored red-brown, there are residues of soluble black-and-acid compounds and finely divided acid resin particles. To remove these, the sour oil is often used at around 1000C with approx. 3 - 6% by weight of active fuller's earth (e.g. Tonsil) and 0.5 - 1 % Hydrated lime powder thoroughly stirred, the mixture brought over a filter press, which separates the earth and delivers yellowish clear oil. Instead of hydrated lime you can neutralization with caustic soda or potassium hydroxide, etc. can also be carried out. In order to use little neutralizing agent, the acid oil is often in the heat blown out with air or inert gas, whereby the free SO2 is expelled. This happens e.g. in hot contact bleaching, where the contact temperature is 200 - 3000G, where hydrated lime can have a detrimental effect.

The used fuller's earth contains approx. 30 - 45 wt.

Residual oil and has so far been deposited in garbage dumps or in pits, since work-up was generally viewed as too costly. That kind of However, the water authorities have recently objected to deposits, since it has been shown that the deposited oily bleaching earth is exposed to the weather, gradually releases oil and poses a threat to groundwater. also the Eliminating the falling off by burning is unsatisfactory because it leads to increased levels Air pollution leads and also expensive dust separation systems (electrostatic precipitators) makes necessary.

Numerous endeavors have already been carried out which required To make bleaching earth oil-free or low-oil in order to be able to deposit it without difficulty to fear. In DRP 942 654 ha-t Kehse a process for the treatment of mineral oil-containing Get bleaching earth protected, but this has not proven itself. There will be mentions that extraction is to be regarded as technically possible, but uneconomical is because the extracted oil is rich in resin and asphalt.

The invention relates to the solution of the following objects, which are summarized the extraction or regeneration of the used bleaching earth is economically feasible can do: a) Carrying out the extraction in such a way that one of the second raffinates corresponding oil is obtained which is free from resin and asphalt; b) further processing the extracted fuller's earth so that it can be used as a floating oil binder in particular for Crude oil, fuels and ileiz oil are suitable; c Further treatment of extracted fuller's earth with the aim of transforming them into full-fledged fuller's earth for their original use.

The invention therefore relates to a method for recycling used ones Fuller's earth from the second refining of Waste oils, characterized that a) the waste earth of a short-term extraction, preferably with low aromatic compounds Benzine hydrocarbons at 10 -subject or at a 5 - 10 S lower Temperature range with suitable halogenated hydrocarbons (e.g. trichlorethylene) is extracted and an extract oil is obtained by separating off the solvent by distillation what is to be achieved is that of the same quality as the second refined product; b) the extracted Fuller's earth possibly after pre-drying a thermal post-treatment at 170-450 Oc, preferably 170 550 Cc, to make it more buoyant; c) the extracted, pre-dried fuller's earth with dilute hydrochloric acid, nitric acid or other suitable acids and after washing and predrying a thermal aftertreatment is subjected to activate them after.

Examples for a): Comparative experiment a) 1: In a laboratory experiment 100 g of waste bleaching earth from the second refining of used oil (motor waste oil) with 400 ml of one Mixture of benzene with regular gasoline 3: 7 boiled on the reflux cooler for 30 minutes. Then the earth was filtered off on a slide at 60-70 ° C, the cake under Press down as well as possible of solvent, removed and in the drying cabinet dried at 100 - 1400C. The dark filtrate was made with a distillation device the solvent removed and a dark brown oil obtained. Yield = 38% by weight, Viscosity 6.5 ° Engler at 50 ° C. This oil could be used as heating oil or as raw oil admit it again.

Experiment a) 2: To get a light-colored raffinate out of the used soil, You have to do this briefly and at room temperature and preferably with a low-aromatic solvent such as white spirit (approx. 16% aromatics) or Shell special gasoline 100/125 (3.5% aromatics) extracted. 100 g of fuller's earth (as above) were mixed with 400 ml of white spirit Stirred intensively at 25 ° C. After 8 minutes, it was filtered off on the suction filter. The better result could be seen from the light-colored filtrate. The earth became how described above, dried, removed from the filtrate in the same way; yield about 57 wt. Appearance of the oil: yellow, an idea darker than the corresponding second refined product. The slight darkening was due to overheating of the oil due to the peeling of the petrol, which is due to a slight smell of orack of the oil could be seen. Viscosity: 6.5À Engler at 50 ° C. The extracted oil was thus identical to the second refined product and resin-free. The dark resin fabrics are therefore remained in the bleaching earth.

Experiment a) 3: Is used in experiment a) 2. Trichlorethylene instead of white spirit used as extraction agent, the recovered secondary refinement is included 250C extraction temperature and 8 minutes stirring a little darker. On repetition of the experiment at 1500 and 8 minutes stirring time, however, practically the same thing is obtained Result, i.e. a lighter extract than that obtained at 250c. One thing is certain that the bleaching earth should be regenerated for its actual purpose and not as an oil binder, you can first extract it cold to make the reraffinate to win and afterwards warmer to remove the resins also @@ ch. to b): Lbsu-a, center-free - do Ver1ei9haversh a) 1: A 250 ml beaker was filled with tap water cd oa.

5 g He @@ @@ f given, within about a minute it was sunk under.

Water 2/3 high was poured into a wide 500 ml Bocher glass. Then 3 ml of heating oil EL were added - and a little later 4 g of soil a) 1 were sprinkled on. The earth soaked up the heating oil relatively quickly and initially floated like a crust. After about a minute, thick drops (about 1 cm in diameter) began to form, which sank to the bottom of the beaker, with a tea strainer (1 mm mesh size) but could be fished out.

Extracted soil a) 2: The same swimming experiment with soil alone on water showed that it is noticeably better buoyant, remains about 3-4 minutes on the surface, but then also begins to sink. When trying with heating oil EL if this was absorbed very quickly, it formed a solidified crust that coalesced with the The tea strainer could be removed without smearing. Formed after about 6 minutes however, there is a bulge on the flat lower surface of the crust, which is a little later than thick drop sank, etc. It was found that the drying of the extracted Fuller's earth at around 250 ° C visibly improves the earth's floating capacity. Finally it was also observed that # by mixing ce. 10% cork flour with the earth Oil binding attempt can prevent the cake from sinking entirely, cork flour can be replaced by other fine-grain floating matter, e.g. rubber powder, etc.

O.Sturz and K.Klein have in "Deutsche Gewässerkundliche Mitteilungen" 8, 127-138 (1964) a large number of commercial oil binders for their properties examined. Unfortunately, the prices of the oil binders could not be used in these comparisons be included. It is natural, however, for the consumer of oil binders not only asks about the quality, but especially about the elimination a certain amount of oil in the oil binder consumption costs. In this list corresponds to the oil binder according to the invention in terms of its properties about the commercial product Skoperl. In contrast to this, however, the extracted fuller's earth is much finer-grained (less than 0.3 mm), thus absorbs fuels and oils faster and surprisingly forms a coherent crust as a result of an interlocking with the oil, which is like a Kind of binder works. In relation to its own weight, the extracted soil can do something like that Absorb 1.2 - 1.3 times as much oil. Since the raw material costs nothing as a waste product, the nailing and sifting have already been carried out, despite the extraction and post-treatment costs the cost is relatively low, with the fact that the second refined material is recovered also lowers these costs. to c): c) 1. Bleaching effect of the earth a) 2: acidified spindle oil was made with 3% fresh clay and 1% hydrated lime at 100 ° C Stirred vigorously in a 500 ml enamel beaker for 5 minutes and then immediately open sucked off the suction filter. According to ASTM, the filtrate had a color number of 1.5-2, Belm The same experiment with the extracted soil (a) 2) gave the color number 2--2.5. The same color number was only obtained when twice the amount of bleaching earth was used. c) 2. Extraction of the earth a) 2 with dilute hydrochloric acid: 50 g of earth (a) 2) were with 4 times the amount of 20% hydrochloric acid for about 10 minutes at 70 - 90 ° C in a beaker intensely, stirred and then sucked off again on the suction filter with an acid-proof filter and washed with distilled water.

The cake was dried in a drying cabinet at 110 ° C. and then dried briefly heated to 7006C in a muffle furnace. The regenerated earth was opposite the fresh soil is a little lighter in color. In the bleaching experiment, as stated under c) 1, it was found that there was now no difference in the bleaching effect compared to the fresh earth more existed. Was the regenerated earth (c) 2) again after the, bleaching test, As mentioned, extracted and regenerated, it turned out that here too they were not Had suffered a loss of bleaching effect. Further experiments then showed that # heating to 700 ° C in the muffle furnace is not necessary at thermal post-treatment in air, e.g. fluidized bed furnace, the same result is obtained at around 350 - 450 ° C. In the present case it was diluted Hydrochloric acid used because hydrated lime is used for neutralization in bleaching became.

Dilute nitrous acid can also be used just as well; through which the lime nitrate solution could even be used for fertilization purposes. ~ Is sulfuric acid not suitable because it leads to gypsum precipitation in the earth. One could but use them if, for example, neutralization is carried out with KOH.

The advantages of the method follow from the above experiments of the invention: On the one hand, good secondary refined material is recovered (value approx. DM 200, - to 400, - / ton), on the other hand there are two ways of recycling for the extracted fuller's earth: 1) the easier way (b) leads to a useful one buoyant oil binder (value DM 200 to 400 / ton); 2) the greater way (c + d) supplies the bleaching earth required for the secondary refining of used oil - at a low level Losses in the original quality back @ value DN 400, - / ton).

A waste oil processing plant, which annually 10 000 t of second refined produces there for fresh bleaching earth annually @ @a.

DM 140,000 from and, peleriierlf at De @ @nie der Abfallerde Approx. DM 100,000 in oil value. This cost justifies a facility for that Recycling the waste earth.

A technical facility for the extraction of small quantities Solvent gets by, would be about the following: The used bleaching earth is mixed in a stirrer with pearly spirit to a slurry, which is used to fill the filter press serves. The filtrate goes into a collection tank. The remaining oil is in the press displaced countercurrently by pumping through a certain amount of gasoline. hit Steam is gently driven off the gasoline from the press via a condenser. the Main amount of moisture from the approx. 1300C hot cake mass in the press z. B. be removed with inert gas. The press is emptied and after cooling down filled again. The gasoline is converted from the extract solution in a downstream The distillation system is separated from the oil and goes back to the storage tank, the oil in a collection tank. The pre-dried fuller's earth is heated with hot air in a fluidized bed oven thermally treated. When using trichlorethylene or substances other than Extraction agent, the procedure is largely the same.

The procedure for hydrochloric acid extraction is similar: the pre-dried Extracted fuller's earth is put into a stirrer and is mixed with hot dilute hydrochloric acid stirred up to a sludge. This is then pumped over to the plastic filter press, the filtrate draining into a plastic tank. Pipelines and valves are also made of plastic. The filter cake is washed out in countercurrent.

Thin washes can be used for the next extraction with concentrated Acid can be concentrated and reused. The filter cake is made with warm air blown out, the press emptied. The pre-dried fuller's earth is placed in a fluidized bed oven finished with hot air. Will not be used by binder, but to be reused worked as fuller's earth, it is more convenient to acid treatment of the extracted Earth according to the thermal. Make fluidized bed treatment.

Although the procedure according to the invention specifically for the secondary refining is worked out from waste oils, there are similar cases in the production of primary raffinates, where the waste earth can be recycled in the same way.

This applies, for example, to bleaching processes in the production of mineral oils, Synthetic oils as well as animal and vegetable oils and beds.

Claims (2)

P a t e n t a n s p r ü c h e 1.) Process for recycling used bleaching earth from the secondary refining of waste oils, characterized in that that a) the waste earth of a short-term extraction, preferably with low aromatic compounds Subject to gasoline hydrocarbons at 10 - 45 S Q or at a 5 - 10 ° C lower Temperature range with suitable halogenated hydrocarbons (e.g. Trichlorethylene) is extracted and separated by distillation of the solvent an extract oil can be obtained that is qualitatively similar to that of the second refined product equals: b) the extracted fuller's earth after pre-drying a thermal aftertreatment at 170 - 45o ° C, preferably 170-550 9c, is subjected to make them more buoyant close; c) the extracted, pre-dried fuller's earth with dilute hydrochloric acid, Nitric acid or other suitable acids treated @@@@ and after washing out and pre-drying is subjected to a thermal aftertreatment in order to reactivate it. 2.) The method according to claim 1, characterized in that the after b) recovered bleaching earth, optionally after adding up to 15% cork flour as a floating oil binder mainly for removing crude oil, fuels and Fuel oil is used. ).) The method according to claim 1 and 2, characterized in that the according to c) regenerated fuller's earth is used instead of fresh fuller's earth.