DE4317046A1 - Process for draining waste oil using surface-active compound - Google Patents

Description

The invention relates to a method for dewatering tech natural waste oil, which is either an oil-in-water Emulsion or a water-in-oil emulsion and each consists of at least 15% oil. Such emulsions fall with the Processing of technical oil-in-water emulsions, for example by creaming in a mechanical separator, by Enrichment using membrane filtration processes or as a result ner primary fission.

Used and disposed oil-in-water emulsions fall into of the metalworking industry in large quantities. A source for this are cooling lubricant emulsions, which are used for machining Metalworking are used and the oil content of about Have 2-5%. Even if such emulsions take a long time - until to several months - can still be used finally consumed and must be disposed of. Another Technical emulsions, for example, are a source of waste emulsions cleaning and cleaning baths that run through during their operating time registered oil build up an oil content of about 1-5% and the continuously de-oiled and / or at the end of its usability must be disposed of discontinuously. Waste emulsions of  mentioned type represent oil-in-water emulsions. Work-up and disposal usually begins with one Concentration or a primary fission in a water-rich and in an oil-rich phase.

Such phase separation takes place, for example, in mechanical Separation devices of sewage systems by the action of Gravity automatically, with an "old oil" in the form of an oil-rich Oil-in-water emulsion with an oil content of over 15% by weight frames. Another primary separation option is that the emulsion of a membrane filtration, for example one Micro or ultrafiltration subjects and turns them into an oil-rich Retentate with an oil content above 15 wt .-% as well as in a practical splits oil-free permeate. In both of these cases lies after first separation step an oil-rich oil-in-water emulsion in front.

The primary fission can, as described in DE-A-41 26 914, by an electrolytic charge neutralization of the oil droplets takes place is a thermal cleavage by heating the waste emulsion also possible, but due to the high energy requirement little ge common. The processing of waste emulsions often begins with the fact that the emulsion of a primary fission with chemical Submits to emulsion splitting. For chemical emulsion splitting come either strong acids, inorganic salts and / or orga African emulsion splitter into consideration. The organic Emulsion breakers, which often consist of cationic polymers, have the great advantage that they split in the oil phase remain and therefore not to further contamination of the Water phase contribute and no additional sludge.  

Emulsion splitters for such primary splitting are in large numbers known in the prior art, for example, DE-A-40 09 760 synthetic polymers based on polyimines, Polyether polyamines, polyamines and polyamide amines or quaternized polyamines and quaternized polyamide amines, furthermore cationic copolymers made of acrylamide and different proportions cationic monomers or oligomers and homopolymers of Dimethyldiallylammonium chloride. Of these, there have been organic ones cationic emulsion breakers based on polyamines, polyimines, Particularly well proven are polyether polyamines and polyamide amines.

DE-A-40 09 760 describes a two-stage process for primary splitting an oil-in-water emulsion using both organic and organic emulsion splitters. In doing so the emulsions to be split primarily with an organic one cationic emulsion splitter of the type mentioned above and then with an inorganic emulsion splitter based on salts polyvalent metals, especially aluminum, iron and Calcium, added. After separating the creaming oil phase, the What still has a low residual hydrocarbon content a second splitting step with another anorga African emulsion splitter followed by an organic anionic Subjected to emulsion splitter.

The oil phase separated during chemical primary fission lies usually as a water-in-oil emulsion with an oil content of more than 15% by weight. If you ent in the primary fission Recycle, deposit, or process standing water-in-oil emulsion want to burn, the residual water content proves to be a hindrance or at least as a cost driver. Hence it is in general advantageous to continue this emulsion by a secondary cleavage rid of water. The task this poses  further drainage is related to the problem of drainage of crude oil emulsions used in oil production either directly or as a result of tenside-supported tertiary funding attack. As DE-A-40 40 022 explains, this is on Secondary fission of a technical old to be carried out as required oil cannot be compared with the splitting of a crude oil emulsion. This is related to the fact that the stabilizers of the emulsions in the the two cases show very large differences. Knowledge from The splitting of crude oil emulsions can therefore only be used to a great extent limited to the splitting of technical waste oil emulsions gen. According to the proposal of DE-A-40 40 022 tech niche water-in-oil emulsions, which are the oil phase a primarily split oil-in-water emulsion, that polymers and / or oligomers of ethylene oxide and / or 1,2- Propylene oxide, oxyalkylated phenolic resins, with diisocyanates, Cross-linked dicarboxylic acids, formaldehyde and / or diglycidyl ether Block or mixed polymers of ethylene and 1,2-propylene oxide, Polyether urethanes and / or alkylbenzenesulfonic acid salts as splitters starts. This teaching is based on the splitting of water-in-oil Limited emulsions. There are no indications that the secondary splitters mentioned also for the drainage of oil oil-in-water emulsions with oil contents of more than 15 are sufficient % By weight are applicable, such as in the form of "waste oils" or can be obtained as retentates from membrane filtration processes.

On the one hand, the water-in-oil Emulsions usually through very different stabilizers systems are stabilized and on the other hand the task a further drainage of concentrated oil-in-water Emulsions, there is a need for broader Ent watering agents that are suitable for different stabilizers systems and for both water-in-oil emulsions and oil-in-oil  Water emulsions with oil contents of more than 15% by weight each own. It is the object of the present invention, such to provide broader drainage agents.

According to the invention, this object is achieved by a Process for the drainage of waste oils, the water-in-oil Emulsions or oil-in-water emulsions with an oil content of represent greater than 15 wt .-%, characterized in that one or more surface-active compounds from the groups

• A) Alkoxylation products of fatty alcohols or fatty amines with 8 to 22 carbon atoms,
• B) Aliphatic monoalkyl sulfates or sulfonates with 8 to 22 Carbon atoms,

distributed in the emulsion and phase separation.

The product groups mentioned under A) and B) are known as such. In preferred embodiments, the invention relates
Processes in which the compounds from group A) are selected from ethoxylation products of fatty amines or fatty alcohols with 10 to 18, preferably 12 to 16 carbon atoms with 5 to 29 moles of ethylene oxide and from ethoxylation / propoxylation products of fatty amines or fatty alcohols with 10 to 18, preferably 10 to 16 carbon atoms with 4 to 10 moles of ethylene oxide followed by 1 to 4 moles of propylene oxide, the fatty alcohols or fatty amines preferably being saturated compounds and product mixtures such as those obtained from natural fats and oils are obtained and the alkylene oxide chains are present with a conventional or with narrowed homolog distribution,
such as
Processes in which the compounds from group B) are selected from saturated alkyl sulfates or sulfonates, preferably alkyl sulfates, having 10 to 16 carbon atoms, these in the form of their alkali metal, ammonium, alkylammonium or alkanolammonium salts, preferably as Lithium, sodium, ammonium and / or triethanolammonium salts can be used. Lithium and / or triethanolammonium salts are particularly preferred.

The most suitable for a given drainage task Drainage agents or their combinations and their optimal ones Concentrations must be determined for each sample. They depend on the water content of the samples, on the ver Degree of division of the emulsion, as well as the type and amount of the application send stabilizers. In general, amounts are between 5 ppm and 60,000 ppm based on the total amount to be drained Liquid, effective. It is preferred to work in a concentration range between 100 ppm and 30,000 ppm. The dose end point for the drainage agent can be conveniently on a Än change in the optical appearance of the emulsion to be dewatered know. An indication of the reaching of the dosing end point can be also supply the power consumption of the agitator, which is used in the op minimal dosage. In the general case it is however, preferred the end point of viscosity metering to determine measurements. The viscosity of the emuls to be drained sion instructs on the optimal dosing of the dewatering agent  Minimum on. It does not matter which of the known ones Procedure the viscosity determination takes place. For the sake of one easy handling, the viscosity determination is preferably used to Brookfield.

In special cases it may be advantageous to drainage according to the invention with further drainage to combine means, the dewatering agent from the one individual groups simultaneously or preferably one after the other dewatering emulsion can be added. For example, the drainage agents from group A) combine with N- Alkyl pyridinium salts with an alkyl substituent with 10 to 16 C atoms, trimethylalkylammonium salts with an alkyl radical with 10 to 18 carbon atoms, dimethylbenzylalkylammonium salts with one Alkyl radical with 10 to 16 carbon atoms, with dimethyldialkylammonium salts two identical or different alkyl radicals, each with 6 to 12 carbon atoms and dimethylalkylammonium betaines with an alkyl radical with 8 to 18 carbon atoms, and / or with polymers with the assemblies

and or

where X ^{n- is} a single, double or triple negatively charged preferably inorganic anion, in particular Cl⁻, hydrogen sulfate, sulfate, phosphate or mono- or dihydrogen phosphate.

Furthermore, the drainage agents of group (s) A) and / or B) combine with those described in DE-A-40 40 022 Agents: polymers and / or oligomers of ethylene oxide and / or 1,2- Propylene oxide, oxyalkylated phenolic resins, with diisocyanates, Cross-linked dicarboxylic acids, formaldehyde and / or diglycidyl ether Block or mixed polymers of ethylene and 1,2-propylene oxide, Polyether urethanes and / or alkylbenzenesulfonic acid salts.

The temperature of the emulsion to be dewatered becomes one choose as close to room temperature as possible to save energy, on the other hand, you are on a sufficiently low viscosity grasslands. In general, one will drain at temperatures between 15 and 95 ° C, preferably between 20 and 80 ° C, by to lead.

To carry out the process, the dewatering agents are used methods well known to the person skilled in the art, for example by Stir in, evenly distributed in the emulsion. The separation of the  Emulsion in a water-rich phase and in a dewatered oil phase can under natural gravity in suitable sedi mentation containers. The efficiency of phase separation can by using a continuous or batch process Centrifuge can be increased. Should the emulsion to be dewatered contain sedimentable solids, it is recommended worth separating them before performing the drainage, for example by sedimentation, filtration or by centri fugate.

Examples Embodiments

The dewatering effect of the products according to Ta belle 1 and of comparison substances according to Table 2 was on Mixed emulsions from used cooling lubricant emulsions and used cleaning and degreasing baths of the automobile indu strie checked. The exact composition of this from the Ferti mixed emulsions were not known. Erfin It is essential for the application that they have an oil content after the primary separation <15% by weight. The primary separation of the emul took place ions either by chemical emulsion splitting or by ul trafiltration. The flotates and retentates obtained were used for the tests according to Tables 3 and 4. The Flotate I to III were with by primary fission Polydiallyldimethylammonium chloride, Flotate IV and V by primary cleavage obtained with a cationically modified polyamine the. Retentate I fell on ultrafiltration of the primary mix emulsions through polyvinylidene difluoride membranes. Waste oils were by mechanical separation of the mixed emulsions in oil separators receive.

The used oils, flotates and retentates were removed with the drainage means or comparison substances according to Tables 3 and 4. For this purpose, the samples were stirred with a grid stirrer, the ent added water products and 5 minutes after product addition continued stirring. The end point of the product addition was determined either through the power consumption of the agitator, a viscosity measurement, or after the optical change of the samples. After this Stirring the dewatering agent, the samples were either for 24 Let stand for hours or use a laboratory centrifuge for one  Duration of 5 minutes at a speed of 4000 revolutions centrifuged per minute. The volume fraction of this will decrease outgoing oil phase was determined. It is included in Table 3. The oil phase was usually subordinate to a mixed phase and / or a water phase, which in the practical case if necessary are to be further processed, for example by Return to primary fission or membrane filtration. Before the dewatering step, the water content of the samples was increased averages. Likewise, the water content after drainage obtained oil phase determined. The determination of the water content followed by a 10 g sample of the samples by exposure to Microwaves were evaporated to constant weight.

For comparison, all samples were made without the addition of drainage agents treated physically in accordance with Table 3, d. H. left at the specified temperatures or centrifuge yaws. In no case was a separation of an oil-rich waiter phase of more than 5%.  

Table 1 Drainage agents according to the invention

Group A:

a) C₈-C₁₈-alkylamine (= cocoalkylamine) + 10 EO
b) C₈-C₁₈-alkylamine (= cocoalkylamine) + 12 EO
c) C₈-C₁₈-alkylamine (= cocoalkylamine) + 25 EO
d) C₁₀-C₁₄ fatty alcohol + 6.4 EO + 1.2 PO
e) C₁₂-C₁₄ fatty alcohol + 5 EO + 4 PO

Group B:

k) lithium lauryl sulfate
l) triethanolammonium lauryl sulfate.

Table 2

Reference substances

Claims (12)

1. Process for the dewatering of waste oils which are water-in-oil emulsions or oil-in-water emulsions with an oil content of greater than 15% by weight, characterized in that one or more surface-active compounds from the groups

• A) alkoxylation products of fatty alcohols or fatty amines with 8 to 22 carbon atoms,
• B) Aliphatic monoalkyl sulfates or sulfonates with 8 to 22 carbon atoms

distributed in the emulsion and phase separation. 2. The method according to claim 1, characterized in that the Compounds from group A) are selected from Ethoxylation products of fatty amines or fatty alcohols with 10 to 18, preferably 12 to 16 carbon atoms with 5 to 29 mol Ethylene oxide and from ethoxylation / propoxylation products of fatty amines or fatty alcohols with 10 to 18, preferably 10 to 16 carbon atoms with 4 to 10 moles of ethylene oxide followed by 1 to 4 moles of propylene oxide, which is the fatty alcohols or fatty amines preferably around saturated compounds and around Product mixtures acts as they are made from natural fats and Oils are obtained, and the alkylene oxide chains with konventio neller or with a narrow homolog distribution. 3. The method according to one or both of claims 1 and 2, characterized characterized in that the compounds from group B) are selected from saturated alkyl sulfates or sulfonates, preferably alkyl sulfates, with 10 to 16 carbon atoms and in the form  their alkali, ammonium, alkylammonium or Alkanolammonium salts, preferably as lithium, sodium, Ammonium and / or triethanolammonium salts and especially as Lithium and / or triethanolammonium salts are used. 4. The method according to one or more of claims 1 to 3, since characterized in that the dewatering agent from the Group A) combined with N-alkylpyridinium salts with one Alkyl substituents with 10 to 16 carbon atoms, Trimethylalkylammonium salts with an alkyl radical with 10 to 18 C atoms, dimethylbenzylalkylammonium salts with an alkyl radical with 10 to 16 carbon atoms, dimethyldialkylammonium salts with two same or different alkyl radicals, each with 6 to 12 carbon atoms and dimethylalkylammonium betaines with one Alkyl radical with 8 to 18 carbon atoms. 5. The method according to one or more of claims 1 to 4, characterized in that the dewatering agents from group A) are combined with polymers with the assemblies
and or and or where X ^{n- is} a single, double or triple negatively charged preferably inorganic anion, in particular Cl⁻, hydrogen sulfate, sulfate, phosphate or mono- or dihydrogen phosphate. 6. The method according to one or more of claims 1 to 3, since characterized in that the drainage agents from the Groups A) and / or B) combined with agents from the group the polymers and / or oligomers of ethylene oxide and / or 1,2- Propylene oxide, oxyalkylated phenolic resins, with diisocyanates, Cross-linked dicarboxylic acids, formaldehyde and / or diglycidyl ether Block or mixed polymers of ethylene and 1,2-propylene oxide, Polyether urethanes and / or alkylbenzenesulfonic acid salts. 7. The method according to one or more of claims 1 to 6, because characterized in that the drainage agents in Ge total concentrations between 5 ppm and 60,000 ppm, preferably between 100 ppm and 30,000 ppm, based on the total amount of the liquid to be drained. 8. The method according to one or more of claims 1 to 7, because characterized in that the drainage at temperatures  between 15 and 95 ° C, preferably between 20 and 80 ° C carries out. 9. The method according to one or more of claims 1 to 8, because characterized in that it is the to be drained Waste oil is a water-in-oil emulsion that acts through primary cleavage of an oil-in-water emulsion was obtained. 10. The method according to one or more of claims 1 to 8, because characterized in that it is the to be drained Waste oil is an oil-in-water emulsion. 11. The method according to claim 9 or 10, characterized in that after mixing the dewatering agent with the Emulsion performs a phase separation by centrifugation.