WO1993004793A1 - Process and device for treating contaminated substances - Google Patents

Abstract

The description relates to a process for treating contaminated substances, especially soils or liquids, in which a slurry of the contaminated substances is introduced into at least two coherent jets of pressurised water. The pressurised jets are directed towards one another in such a way that they strike one another. Thereafter the slurry thus treated is immediately separated into the pollutant and the decontaminated substance. A device for implementing the process has a reaction chamber fitted with three nozzle devices to introduce three coherent water jets. The nozzle devices are positioned in such a way that the water jets strike one another in a predetermined region inside the reaction chamber.

Description

 Method and device for processing contaminated substances

The present invention relates to a method and an apparatus for processing contaminated substances, in particular contaminated soils and contaminated

Liquids.

Contaminated substances, such as, in particular, contaminated soils or contaminated liquids, are preferably obtained as intermediate or end products during industrial processing or are widespread as so-called contaminated sites at corresponding industrial locations. Until recently, the way in which these contaminated substances were disposed of is no longer practicable because of the lack of landfill areas and the danger associated with storage. For this reason, these contaminated substances are being processed more and more. In principle, three methods are known for working up contaminated substances.

The thermal processes, which have in the meantime reached a high level of development, have the disadvantage that unreacted toxic compounds or those formed during combustion have to be removed from the exhaust air.

The biological processes are very time-consuming, require large areas and can currently only be used on monocontaminated soils.

The previously known floor washing systems work with an efficiency which is between about 14% and about 50% depending on the respective contamination, i.e. only about a maximum of half of the contaminants in the soil are removed by conventional methods. This in turn means that, due to the high residual contamination, recycling of the soils treated in this way is impossible in many cases.

The object of the present invention is to provide a method and a device for the treatment of contaminated substances, in particular contaminated soils and contaminated liquids, with which the contaminants from the substances can be removed with a particularly high degree of efficiency can be removed.

According to the invention, this object is achieved by a method having the characterizing features of patent claim 1 and by a device having the characterizing features of patent claim 20. In the method according to the invention for processing contaminated substances, in particular contaminated soils and contaminated liquids, a slurry of the contaminated substance is introduced into at least two coherent pressurized water jets. The water jets are aligned with one another in such a way that they collide with one another. The slurry treated in this way is then immediately separated into the contaminants and the substance.

Surprisingly, it was found that a particularly effective separation of the contamination from the substances could be brought about by using the method according to the invention described above. This is attributed to the fact that when the slurry is introduced into the pressurized water jet, differences in the relative acceleration are generated due to the different masses of contaminants and substances, which bring about a reliable separation of the contaminants from the substances. Furthermore, this separation effect is further supported by the fact that when the two water jets directed against each other collide, a different braking of the contaminants and substances, which differ in mass, is brought about, whereby a complete separation between the contaminants and the substances is brought about. This in turn has the consequence that correspondingly decontaminated substances are obtained after using the method according to the invention, the content of contaminations of which is between 0% by weight and a maximum of 4% by weight, based on the originally present ones

Contamination, varies. Such a substance can then be reused without problems while the contaminations are separated by the method according to the invention __ 4 _

either deposited as hG * _-_ ι __ <j __; _ eπtrιerτ_.e contaminations or processed and reused accordingly.

In the method according to the invention, the term contaminated substances is understood not only to mean the contaminated soils or contaminated liquids already mentioned above. Rather, this term also includes sludges of all kinds, liquids which occur in industrial processing, for example Drilling or process oils, powdery and fine-grained bulk goods and dusts.

With regard to the pressure of the water jets, it should be noted that in the process according to the invention this pressure varies between 250 bar and 3000 bar, in particular between 1000 bar and 2500 bar. The selection of the above-mentioned pressure range depends on which contaminations are present and how firmly these contaminants adhere or are bound to the respective substance. Thus, in the method according to the invention, one will preferably work in a pressure range of the water jets of between 1000 bar and 2500 bar if the contaminations are bound to soils which are difficult to open and which have a high proportion of clays, loam, Latvian stones and cohesive silt. are attached. In the case of soils which are easy to digest, such as in particular sandy soils, and contaminations which are readily soluble, emulsifiable or dispersible in water, the process according to the invention is carried out in a pressure range between about 250 bar and about 1000 bar, in particular in a range around 1000 bar (700 bar - 1300 bar).

The alignment of the water jets toward one another previously described in the method according to the invention has the further advantage that abrasive wear effects that occur when using a water jet on the walls of a reaction space used for this purpose can be effectively prevented since the energy contained therein is absorbed by the impact of the two water jets on one another. This applies in particular to a particularly suitable embodiment variant of the method according to the invention, in which three water jets are allowed to collide with one another, the water jets being oriented at an angle of 120 ° relative to the horizontal. These water jets are then preferably oriented at an angle between 10 ° and 80 °, in particular at an angle of 45 °, relative to the vertical, so that any abrasive, deflected partial flows of the water jets which may arise during the energy absorption described above are not in the region the reaction chamber in which the nozzle devices are positioned.

With regard to the volume flow, it should be noted that in the method according to the invention the water throughput per water jet is up to 70 / min, in particular between 10 1 / min and 50 1 / min.

The speed of the water jets at the outlet of the

Nozzle devices vary between 200 m / sec and

600 m / sec, especially between 250 m / sec and 400 m / sec.

If a slurry was mentioned above in connection with the process according to the invention, this should not only be understood to mean an aqueous suspension or dispersion of a correspondingly contaminated solid, but also an emulsion of a liquid which preferably also contains water. However, an aqueous sludge in which the solids have a grain size of less than 2 m, in particular less than 400 μm, is preferably used in the process according to the invention. Here it was found that such a sludge could be introduced without problems into the pressurized water jets without clogging the nozzle devices required in the method according to the invention. This is particularly true when the slurry has between 10% and 60% by weight solids with a grain size less than 1 micron.

A further advantageous embodiment of the method according to the invention provides that the during

Treatment resulting gas or mist-like pollutants dissipates, especially suction. In this case, these gas- or mist-like pollutants are then either attached to a suitable adsorbent or absorption medium, introduced into a suitable washing liquid or separated by distillation.

In order to prevent recontamination of the decontaminated substances in the process according to the invention, the appropriately treated slurry is immediately separated into the contaminations and the substance. There are several options for this.

For example, a first, preferred process variant provides that a binder is added to the slurry and then the slurry is introduced together with the binder into the two coherent pressurized water jets. The consequence of this is that the contaminants, which are appropriately separated from the contaminated substance due to the different masses and the resulting different acceleration, are adsorbed, absorbed and / or stored by the binder, so that subsequently only separation the binder loaded with the contaminants from the appropriately cleaned Substance must be done. This separation can then preferably take place on the basis of different densities or via appropriate filters.

A second embodiment provides that, after the water jet treatment, the contaminations are separated from the substance by coagulation. The correspondingly treated slurry is then immediately removed from the reaction space and transferred to a corresponding basin, with an addition of

Flocculants are used. Depending on the contamination, these flocculants can either be the classic flocculants, such as, for example, iron chloride, iron sulfate, aluminum sulfate, or polymeric flocculants, such as, in particular, starch, glue, polyacrylamide, polyacrylates, polyethyleneimine or polyethylene oxide. The resulting flocculations are filtered to remove the contamination.

A third embodiment of the process according to the invention provides that the treated slurry is subjected to flotation in order to separate the contamination from the decontaminated substance. Here, the treated slurry, as already described above for the coagulation, is withdrawn from the reaction space and fed to the flotation, the anionic surfactants, cationic surfactants and / or amphoteric surfactants known per se being used as flotation agents.

If the contamination contains heavy metals, it is advisable to carry out electrocoagulation in addition to or instead of the separation processes described above. In order to make the process according to the invention particularly economical and ecologically sensible, it is advisable to reuse the water required for the process according to the invention. This may require coarse solids to be removed by filtration.

In order to accelerate the separation of the contaminants from the substance, a further embodiment of the method according to the invention provides that a surfactant, an organic solvent, a block polymer and / or a defoamer are added to the water jet. The concentration of the surfactant varies between 0.05% by weight and 0.0005% by weight, based on the weight of the contaminated substance.

Defoamers used in the process according to the invention are either defoamers based on silicone oil or conventional defoamers based on mineral oils.

The known anionic and / or nonionic surfactants are suitable as surfactants.

Particularly good results are achieved in the process according to the invention when a surfactant based on a dioctyl sodium sulfosuccinate is used in the concentration range mentioned above.

The use of block polymers, in particular those made of propylene oxide and ethylene oxide, is appropriate whenever the contamination consists or contains tar, tar-like or tar-like substances. It was found here that such contaminations, in particular then, very quickly become detached from the contaminated substance separate if this block polymer is present in the water jet.

C Lösungsmittel-C4 alcohols (methanol, ethanol, i-propanol, n-propanol and butanol) in particular can be used as solvents in the process according to the invention.

The amount of water required for the method according to the invention depends on the type of substance and the chemical structure of the contamination. Usually, the amount of water required varies between 15 1 to 800 1 water per ton of substance, with readily soluble and easily accessible substances, such as, for example, correspondingly fine-grained sand, amounts of water between 15 1 and 100 1 per ton of substance, and with appropriately heavier soils, amounts of water between about 100 1 and about 400 1 water per ton of soil and in the case of poorly soluble, difficult to digest soils, which have a high proportion of clays, loam, Lettenkeupern and cohesive silt, amounts of water between about 400 1 and about 800 1 per ton of soil are required.

The present invention further relates to a device for carrying out the method according to the invention described above.

The device according to the invention has a reaction space which is provided with three nozzle devices for introducing three coherent water jets. The nozzle devices are positioned in such a way that the water jets collide with one another in a predetermined area within the reaction space.

In a particularly suitable embodiment of the device according to the invention, the nozzle devices are of this type positioned that they are each offset by 120 ° relative to the horizontal as seen over the circumference of the cylindrical reaction space. In particular when the nozzle devices are at an angle between 10 ° and 80 °, in particular at an angle of, relative to the vertical

45 °, it is ensured that the walls of the reaction chamber and in particular the rather cost-intensive head area, on which the nozzle devices are provided, are not damaged due to the deflected abrasive partial water jets.

A wear-resistant inner lining with which the reaction space is provided enables trouble-free long operation of the device according to the invention.

This applies in particular to a particularly suitable embodiment of the device according to the invention, in which the cylindrical reaction chamber has a first area for receiving the nozzle devices and a second area arranged underneath, which is provided with the wear-resistant inner lining. In this case, the two areas can be moved, in particular rotated, relative to one another, so that abrasive scattered rays which arise when the water jets collide do not constantly impinge on the same area of the inner lining. Rather, the movement and in particular the rotation of the two areas relative to one another uniformly load the wear-resistant inner lining over the entire circumference, as a result of which the service life of such a device is considerably extended.

Should wear of the inner lining nevertheless occur, a further embodiment of the device according to the invention provides that additionally or instead the rotation described above, the two areas are axially displaceable relative to each other. This ensures that if wear is detected, only an axial displacement is required in order to be able to continue operating the device according to the invention without interruption.

Another embodiment of the device according to the invention has a reaction chamber which has a suction opening on the head side and a discharge opening arranged opposite the suction opening. In this case, the gaseous or mist-like pollutants formed in the process according to the invention are withdrawn from the reaction space via the suction opening on the head side, while the discharge opening, which preferably extends over the entire base area of the cylindrical reaction space, for removing the treated ones Slurry serves.

Advantageous further developments of the method according to the invention and of the device according to the invention are specified in the subclaims.

The device according to the invention is explained in more detail below using an exemplary embodiment in conjunction with the drawing. Show it:

Figure 1 is a plan view (in section) of the embodiment; and

FIG. 2 shows a side view with the wall partially broken out.

In Figures 1 and 2, the same parts are provided with the same reference numerals. A device designated overall by 1 has a cylindrical reaction chamber 2 which is provided with three nozzle devices 3, 4 and 5. Here, the three nozzle devices 3-5 serve to introduce three coherent water jets.

As can best be seen in FIG. 1, the three nozzle devices are aligned at an angle 06 of 120 ° relative to the horizontal and are positioned such that the coherent water jets generated by the nozzle devices 3-5 align in the center of the reaction chamber 2 ¬ collide, as shown by reference numeral 6 in Figure 1.

As can best be seen from FIG. 2, the nozzle devices 3-5 are arranged at an angle of 45 ° relative to the vertical.

The reaction space 2 has a first area 8 for receiving the nozzle devices 3-5 and a second area 9 arranged below it, which is provided with a wear-resistant inner lining 10. This is a ceramic material, an elastomer-coated material, a hard metal or a boron carbide inner lining.

The second area 9 is rotatably arranged on the first area 8, a rotating ring 11 ensuring the rotatable mounting. Two grooves 12 provided with seals ensure that the connection of the two regions 8 and 9 is fluid-tight. During operation of the device 1 there is a continuous rotation of the second area 9. This ensures that the inner lining 10 wears evenly due to abrasive stray radiation, so that a punctiform or area-specific load on the inner lining is prevented. If the inner lining is now worn out due to the use of the device, only the second area, which can be manufactured correspondingly inexpensively, is replaced. A lower discharge opening 13 serves to discharge the treated slurry, while the gaseous or mist-like pollutants formed during the treatment are sucked off via a suction opening 14 provided at the head.

Claims

Claims 1. Process for processing contaminated substances, in particular soils and liquids, characterized in that a slurry of the contaminated substance is introduced in at least two coherent pressurized water jets S, that the water jets are aligned with one another in such a way that they collide with one another and that the slurry thus treated is then immediately separated into contamination and decontaminated substance. 2. The method according to claim 1, characterized in that water jets with a pressure between 250 bar and 3000 bar, in particular with a pressure between 1000 bar and 2500 bar, are used. r. 3. The method according to claim 1 or 2, characterized gekennzeich¬ net that three water jets are allowed to collide. the water jets being oriented relative to one another at an angle of 120 ° relative to the horizontal. 4. The method according to any one of the preceding claims, characterized in that the three water jets are oriented relative to the vertical at an angle between 10 ° and 80 °, in particular at an angle of 45 °. 5. The method according to any one of the preceding claims, characterized in that water jets with a volumetric flow of up to 70 min, in particular between 10 1 / min and 50 1 / min, are used per water jet. 6. The method according to any one of the preceding claims, characterized in that water jets with a Speed between 200 m / sec and 600 m / sec, in particular between 250 m / sec and 400 m / sec. 7. The method according to any one of the preceding claims, characterized in that the slurry contains solids with a grain size less than 2 mm, in particular less than 400 microns. 8. The method according to claim 7, characterized in that the slurry 10 to 60 wt.% Solids with a Has grain size less than 1 micron. 9. The method according to any one of the preceding claims, characterized in that the resulting gas or mist-like pollutants are removed during the treatment. 10. The method according to any one of the preceding claims, da¬ characterized in that the separation of the contact inations and the decontaminated substance by coagulation and / or flotation. 11. The method according to claim 10, characterized in that one removes heavy metals by electrocoagulation following the separation. 12. The method according to claim 9 or 10, characterized gekenn¬ characterized in that one carries out the flotation with the addition of a ten-sided flotation agent. 13. The method according to claim 10, characterized in that one carries out the coagulation with the addition of a salt and / or a polymeric coagulant. 14. The method according to any one of the preceding claims, characterized in that a binder is added to the slurry and the contaminants attached or bound to the binder are separated from the substance. 15. The method according to any one of the preceding claims, da¬ characterized in that the required water, optionally after filtration, reused. 16. The method according to any one of the preceding claims, characterized in that a water surfactant, an organic solvent, a block polymer and / or a defoamer is added to the water jet. 17. The method according to claim 16, characterized in that the surfactant is added in a concentration between 0.05% by weight and 0.0005% by weight, based on the weight of the contaminated substance. 18. The method according to claim 16, characterized in that an alcohol is used as the organic solvent. 19. The method according to any one of the preceding claims, characterized in that the contaminated substance is treated with 15 1 to 800 1 water per ton of substance. 20. Device for performing the method according to one of the preceding claims, characterized in that three nozzle devices (3, 4, 5) are provided for the introduction of three coherent water jets on a reaction chamber (2) and that the nozzle devices (3, 4, 5 ) are positioned so that the water jets collide with each other in a predetermined area (6) within the reaction space (2). 21. The apparatus according to claim 20, characterized in that the nozzle devices (3, 4, 5) over the circumference of the cylindrical reaction chamber (2) are each offset by 120 ° relative to the horizontal. * 22. The apparatus of claim 20 or 21, characterized gekenn¬ characterized in that the nozzle devices (3, 4, 5) are arranged relative to the vertical at an angle between 30 ° and 60 °, in particular at an angle of 45 °. 23. Device according to one of claims 20 to 22, characterized in that the reaction chamber (2) is provided with a wear-resistant inner lining (10). 24. Device according to one of claims 20 to 23, characterized in that the cylindrical reaction chamber (2) has a first region (8) for receiving the nozzle devices (3, 4, 5) and a second region arranged underneath (9), which is provided with the wear-resistant inner lining (10), and that the two areas (8, 9) can be moved relative to one another. 25. The device according to claim 24, characterized in that the two regions (8, 9) are rotatable relative to each other. 26. Device according to claim 24 or 25, characterized in that the two regions (8, 9) are axially displaceable relative to one another. 27. Device according to one of claims 20 to 26, characterized in that the reaction chamber (2) has a suction opening (14) on the head side and a discharge opening (13) arranged opposite the suction opening (14).