DE3044978A1 - METHOD FOR SEPARATING HALOGENATED AROMATIC HYDROCARBONS FROM SILICONE AND HYDROCARBON OILS - Google Patents

Description

30A497

It is well known that polyhalogenated diphenyls, such as polychlorobiphenyls (PCB) and polybromobiphenyls [PBBJ, are toxic materials whose use has been pushed back to environmental concerns. PCBs are ξ, Β due to their thermal stability and Kicht-Entflaisribarkeit, Β. "used -Järiiieaustaus medium. Although i wjräen C2 and PBB in many cases replaced by other innocuous materials? aind these substitutes often remaining PGB cdsr PBB" as dielectric materials for transformers and capacitors and as / erunreinigtj, in Annexes surückbliebea. .Is it possible to use 2 _O S, large transformers _? dis? CB 'Srithalten _u -xu / S. If the ice-lactic liquid is replaced by an "iKiwsltf ^ eüdliches dielectric (usually hydrocarbon-based silicon oil / _s, so the new material is contaminated by the non-tollable entice""): PCB is contaminated.

Such transformer oils? üärraea ^ s'-a-aschmittsl etc. are mostly processed at the place of use in Kicbilsii Tcrricht ^ ng-sn, remove the accumulated waste from the oil or refine it in some other way so that it can be reused in the system. If these oils contain PCB or PBB as impurities, an economical and quick "experience for their separation at the place of use is desirable"

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It is already known that sodium dispersions and Sodium with a high surface area for the separation of impurities

junctions, e.g. halides, from petroleum fractions and other hydrocarbons is suitable; see the brochure "Sodium Dispersions" from U.S.I. Industrial Chemicals Co .. Sodium naphthalene is also used been used to dechlorinate polychlorinated biphenyls; See Akira Oku et al, Chemistry and Industry, November 4, 1978. Im In general, these processes are carried out in batch operation at a fixed location and are therefore suitable not for mobile use.

The invention relates to a process for removing polyhalogenated aromatic compounds from hydrocarbon and silicone oils, which can be used at various locations, in which the contaminated oil is contacted with a sodium dispersion, the mixture is reacted at a temperature above about 75 ^° C. and the particulate and other undesirable Separates material.

Presumably, when the polyhalogenated aromatic compounds are converted, they are converted into harmless polyaromatic compounds. In a preferred embodiment, the contaminated oil is passed through a conduit equipped with a mixer, a hydrocarbon dispersion of sodium is introduced into the contaminated oil in the conduit at a point which ensures thorough mixing, the mixture of oil and sodium dispersion is set at a temperature of at least about 75 ^° C, passes the treated oil through a filter media or other separation device to separate particulate and other contaminating material, and preferably recycles the treated oil back to the system from which it was withdrawn . In a further preferred embodiment, excess sodium that remained after the reaction with the PCB is

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by reacting with a hydrated absorbent added to the system. The hydrated absorbent reacts with existing unreacted sodium, so that when disposing of the used filter bed no hazardous materials are present and no environmental problems exist.

Have in the sodium dispersion used according to the invention the sodium particles preferably have a size of about 1 to 10 μm. However, there are also sodium dispersions with a particle size of about 20 μΐη usable, however require more time. Suitable dispersions are commercially available, e.g. Matheson Light Oil Sodium Dispersion. The production of these dispersions is detailed e.g. in Patt and Tashima, "Alkali Metal Dispersions", D. Van Nostrand Company, Inc., New York (1961).

The amount of sodium dispersion used in the system depends on the concentration of the PCB or PBB contaminants and other existing sodium reactive materials. Before the process is carried out, the contaminated Oil analyzed in the usual way for PCB or PBB, water and acid number. The results of this analysis provide a basis for calculating the amount of sodium that is stoichiometrically required to match the existing, to react with sodium reactive components. Usually a small excess of sodium of about 10% applied. Since the rate of flow of oil through the system is typically about 18.9 to 94.6 liters / min is adjusted as a function of the oil to be treated, the rate of addition of the sodium dispersion to determine the contaminated oil easily.

The method according to the invention is carried out continuously, for example in the device shown _{in drawing r.} The transformer oil to be treated or a

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Other system oil is fed through line 11 to line 12 and a suitable amount of a sodium dispersion which is under a slight nitrogen pressure or under some other displacement load is metered in from the dispersion storage tank 13. The mixture of oil and dispersion then passes through the line to a mixing zone 14, which is designed as a stirring device or, preferably, as a mixing device that creates interfaces, as described, for example, in U.S. Patents 2,747,844, 3,195,865, 3,394,924 and 3 623 09O is described. These static mixers are preferred because they have no moving parts, require no service or energy, are compact and can form an integral part of the piping system. In the drawing, the liquid mixture then enters a heating zone 15 in order to ensure an essentially complete reaction of the halogen compound with the sodium metal of the dispersion. The heating zone can, however, also be arranged at a different point, for example in the mixing stage or even before the sodium dispersion is introduced. It is only necessary that the mixture of sodium dispersion and oil is ^{heated to a temperature above about 75 °} C. so that the reaction proceeds to completion. Generally temperatures are used the reaction mixture from about 100 to 125 ⁰ C, the upper temperature limit is selected for safety reasons so that it is 20 ° C below the minimum flash point of the oil, the recommended by the NEMA (National Electrical Manufactur-ers Association) will. The converted liquid then enters a holding zone 16 and then flows into a separator, for example a filter system 17. The filter system contains any filter media, for example Fuller's earth, aluminum oxide, attapulgite or paper. It goes without saying that particulate material can be filtered off, but other undesired materials can be removed by sorption phenomena. The water-clear or slightly colored filtered oil can be re-used as such and, after cooling, is returned to the circuit via the line to the transformer or the other system. The pump 19 is an example of

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means for circulating the liquid through the system.

The entire system described can be easily mounted on a pallet or a truck and can be used on site be transported to which the hydrocarbon oil should be treated. An effective and inexpensive device for cleaning oils is thus available Available contaminated with aromatic polyhalogen compounds.

Sodium-on-alumina with high surface area is something, though effective but does not enable satisfactory separation of PCBs. Only the sodium dispersion described has sufficient effectiveness and only above about 75 ° C, since below this temperature the PCB separation is incomplete is.

The examples illustrate the invention.

example 1

Following the methods discussed above, a relatively clean hydrocarbon oil containing PCB with a Chlorine content of 49.2 ppm is contaminated, 15 minutes with a stoichiometric amount of a sodium dispersion, whose sodium particles have a size of 1 pm, at 120 Treated to 125 ° C and passed through a 25.4 cm column with a Fuller's earth bed, 2.54 cm in diameter directed. There are five consecutive attempts using the same bed of Fuller's soil already in use carried out. The following table shows the analytical values of the liquid obtained.

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Table I.

at the

Try chlorine sodium

2 1.3

5 1.0

The liquid colorless product thus has both a low chlorine and a low sodium content. the In this and in all of the following examples, chlorine analysis is carried out using the microcoulometric method of Dohrmann carried out. The analytical blank value with uncontaminated hydrocarbon transformer oil is usually 0.8 to 1.8 ppm Cl.

Example 2

According to the method discussed above, heavily soiled transformers that are contaminated with PCBs with a chlorine content of 4O.7 ppm are treated with a superstoichiometric amount of a sodium dispersion, the sodium particles of which have a size of 1 μm, at 120 to 125 ° C and a 25.4 cm column of a bed of Fuller's soil with a diameter of 2.54 cm. The product oil obtained is colorless, has a power factor of 0.0017 at 100 ° C, a resistance of 64 χ 10 ¹² ohm-cm at 100 ⁰ C and contains 2,6ppm chlorine and less than 0.1 ppm sodium. If the experiment is repeated and the material treated with sodium is passed through the previously used Fullers earth, the product is a light yellow liquid with a chlorine content of 8.0 ppm and a sodium content of 2.6 ppm. A third pass of the treated material through Fuller's Earth gives an orange cloudy liquid,

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indicating that when treating heavily contaminated oil, the filter material must be replaced.

Example 3

This example shows the influence of temperature. In Table II are those with the test oil and the sodium dispersion Results obtained from Example 1 mentioned.

Table II Cl (ppm) Time (min) 25.9
30.9
4.6
1.0 Temperature ( ⁰ C) 15th
15th
5
15th 73 -
100 -
120 -
120 - - 75
■ 105
- 125
- 125

The results show that the preferred operating temperature is about 120 to 125 ° C.

Example 4

This example illustrates the use of "high surface area" sodium dispersed on alumina is to remove PCB and influence the dwell time. .

A standard test hydrocarbon oil, the PCB with a Contains chlorine content of 49.2 ppm, is heated to 105 to 110 ° C. The data from this run are in Table III called.

Table III Sample no. Residence time (min) ppm chlorine ppm sodium

1 8.8 1.3 <1.0

2 8.8 1.5

3 8.8 2.4

4 4.3 9.5

5 4.3 10.6 3.0

6 4.3 '6.6

7 1.6 34.7

8 1.6 31, O 6.0

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Although the sodium high surface the chlorine content removed, shows a stoichiometric calculation of the data in Table IV that no effective reduction of PCB content of the oil is obtained even at the preferred temperature 120-125 ⁰ C with continued flow through the system.

Table IV

PCB separation with sodium from high surface bed: 10% NaAl ₃ O ₃ (28-48 mesh, 12g Na, 120g Al ₃ O ₃ ) Charge: test oil with 49 ppm Cl (PCB)

Sample number Throughput total flow 8th 17th 17th (ml) chlorine approximate (ml / min) volume of the sample 10 17th 17th ppm PCB content 17th 17th 17th of the treat oil temperature: 100-110 ° C 35 17th 255 th oil oil temperature: 74 - 77 ⁰ C 1 35 17th 530 1 2 35 17th 784 17.0 34.0 2 3 95 17th 24.0 48.0 3 4th 95 17th 284 36.6 73.2 5 17th 17th 403 6th oil temperature: 120-12 5 ° C 522 1.3 2.6 7th 1 857 1.5 3.0 8th 2 992 2.4 4.8 9 3 1127 9.5 19.0 ■ 4 1477 10.6 21.2 5 1727 6.6 13.2 6th 2811 34.7 69.4 7th 31.9 63.8 8th 180 13.6 27.2 9 527 985 7.0 14.0 1994 2.9 5.8 2760 1.8 3.6 3075 2.1 4.2 3380 2.7 5.4 3690 2.1 4.2 4764 8.1 16.2 13.2 26.4 25.0 50.0

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Example 5

The procedure of Example 5 is contaminated with PCB at 100 ° C oil (40.7 ppm chlorine) and with a sodium dispersion repeated, which has a particle size of 20 μΐη. The following Table V shows the effectiveness of sodium with this particle size:

(min) Tabel V chlorine Time ppm , 9
, 7
, 0 5
10
15th 36
29
27

Example 6

The procedure of Example 1 is followed using alumina (Filtrol 24 and Florosil) as absorbents repeated, achieving similar PCB separation but staining the product somewhat in most cases is. Filtrol 24 and Florosil are quite effective, but the bed clogs up quickly. These absorbents are therefore less preferred than Fuller's earth.

Example 7

When repeating example 1 with a transformer silicone oil, contaminated with PCB, the chlorine content is reduced to a similarly low level.

In another embodiment of the method according to the invention the treated product removed from the holding tank 16 is reacted with a hydrated absorbent, to remove any remaining sodium particles. Such an absorbent as hydrated silica or silicate, can be added to the product from the holding tank are stirred thoroughly while holding for a short time (about 1 to 5 minutes) and filtered with a technical filter before passing through the filter 17. On the-

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In this way excess / unreacted sodium particles react with the water of the hydrated absorbent, allowing easier filtration and a cleaner product be achieved. In an alternative method, the hydrated absorbent can also simply be used alone as a filter medium or incorporated into the bed of another filter material; i.e. the hydrated material can be a lower, middle or upper layer in the filter bed of a non-hydrated filter media used to filter the treated oil. Other examples of hydrated absorbents are finely divided attapulgite (e.g. RVM and LVM with a Size up to 200 mesh from Engelhard Industries) and hydrated magnesium silicate (e.g. Britesorb 90 from the Philadelphia Quartz Company}. This embodiment is illustrated in the following examples.

Examples

As in Example 1, 100 ml of test oil with a chlorine content of about 50 ppm (PCb) are used for 15 minutes at 120 to 125 ° C treated with 20 drops of a sodium dispersion (particle size 1 µm) in light oil. The hot oil is then added with 1 g finely divided hydrated silicon dioxide (HiSiI 233 from PPG Industries) added, stirred for 3 to 4 minutes and 45 minutes under. Let stand to cool. Obtained when filtering the material through a paper filter get a water clear oil product that is less than 1ppm Contains sodium, less than 1 ppm chlorine and less than 10 ppm silicon.

If, in this example, contaminated oil is used (90 ml oil from Example 1 + 10 ml used, contaminated Transformer oil), essentially the same results will be obtained received, but the filtered oil is slightly yellow. If one uses a stark under the same conditions contaminated oil, the filtered oil obtained is deep orange and contains 2.8 ppm chlorine, 116 ppm sodium and less than 1 ppm silicon.

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-13- 30U978

Repeating Example 8 with the test oil but using 1 g of attapulgite (up to 200 mesh) in place of hydrated Silicon dioxide, the oil obtained is as clear as water. If the oil is dirty, 2 g attapulgite make one clear orange oil.

Example 9

A test oil with a chlorine content of 49 ppm is treated with the sodium dispersion of Example 8 and through a Passed column of RVM attapulgite (50/80 mesh). The received Oil is clear as water and has a greatly reduced chlorine content.

Example 10

An experiment is carried out according to Example 9, but used one column, the upper third of which is made of RVM attapulgite and the lower two thirds of LVM attapulgite (each 50/80 mesh). The oil flowing off is somewhat due to the presence of water and / or fine clay particles cloudy, but the chlorine content of the oil is reduced from 49 ppm to 9.3 ppm. The oil reacts with the test Litmus paper neutral. If the oil contains water, it can easily be vacuumed before reuse split off. However, by using a larger amount or a more effective hydrated absorbent, the oil can be used without Water breakthrough to be treated.

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Claims (9)

GODFATHER (JTANWALTe
SHIP GUARD STREHL SCHÜBEL-HOPF EBSINGHAUS FINCK MARIAHILFPLATZ 2 Λ 3, MÖNCHEN SO '• ί Γ) Λ / Q 7 ß = «= <==! ρηϋτΡΑΡμ άποικο, n.aooo MÖNCHEN as O U H ι ν / POSTAL ADDRESS: POSTFACH 95 OI 6O ₁ D-8OOO MÖNCHEN 95 SO PROFESSIONAL REPRESENTATIVE BEFORE THE EUROPEAN PATENT OFFICE KARL LUDWIG SCHIFF (196A-197S) OIPL. CHEM. QR. ALEXANDER V. FÜNER DIPL. ING. PETER STREHL DIPL. CHEM. DR. URSULA SCHUBEL-HOPF DIPL. ING. DIETER EBBINGHAUS DR. ING. DIETER FINCK TELEPHONE (089) 48 20 54 TELEX 5-S3 66S AURO D TELEGRAMS AUROMARCPAT MUNICH DEA-13 481
SÜNOHIO November 28, 1980 "Process for the separation of halogenated aromatic hydrocarbons from silicone and hydrocarbon oils " Claims Process for the separation of halogenated aromatic hydrocarbons from silicone and hydrocarbon oils which are contaminated with biphenyls,
characterized in that the contaminated oil with a dispersion of sodium that
has a particle size of about 1 to 20 ».in, mixed in a hydrocarbon, the mixture of oil and
Sodium dispersion is reacted at a temperature above about 75 ⁰ C and the treated oil passes through a separation device to separate particulate and other contaminating material. 130036 / 0S96 2. The method according to claim 1, characterized in that the treated oil is passed through a filter medium. 3. The method according to claim 1 or 2, characterized in that the remaining in the treated oil Sodium particles react with a hydrated absorbent and then the particulate and other contaminants Separates materials. 4. The method according to claim 3, characterized in that one uses hydrated silica, attapulgite or hydrated magnesium silicate as the hydrated absorbent . 5. The method according to any one of claims 1 to 4, characterized in that a temperature of about 120 to 125 ⁰ C is used. 6. The method according to any one of claims 1 to 5, characterized in that the particle size of the sodium is about to 10 μπι amounts. 7. The method according to any one of claims 1 to 6, characterized in that polyhalogenated biphenyls, in particular polychlorinated biphenyls. 8. The method according to any one of claims 1 to 7, characterized in that the oil is a transformer oil Is silicone or hydrocarbon based. 9. The method according to claim 8, characterized in that the transformer oil is in circulation to the transformer from which it was withdrawn. 130036/0596