DE2514862A1 - METHOD FOR TREATMENT OF WATER CONTAINING PHENOLS - Google Patents

Description

25H862

PATENT LAWYERS

TER MEER - MÜLLER - STEINMEISTER

D-8OOO Munich 22 D-48OO Bielefeld

Triftstrasse 4 Siekerwall 7

(ET) 7132/37
tM / th

SOCIETE POUR L'EQUIPEMENT DES INDUSTRIES CHIMIQUES SPEICHIM, 106 rue d'Amsterdam, Paris, France

Process for the treatment of waste water containing phenols.

Exe invention relates to a method and an apparatus for Treatment of wastewater containing phenols and ammonia compounds, especially those that occur in coking plants.

Among the classic methods of treating industrial wastewater we already know what consists in burning the water and the products it contains by burning the Introduces waste water into the interior of a furnace, for which purpose a furnace

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One used for liquid fuel, which vaporizes the water, and one used for destroying the fuel it may contain harmful components ensures a sufficiently high temperature. The heat released is usually in a steam boiler recovered to form steam that can be put to various uses.

The direct treatment of coke plant wastewater with the help of this process cannot be done economically. Complete burning of this wastewater would result in Failure to utilize the very large amounts of steam formed result in unbearably high fuel consumption. In fact, this wastewater falls in very large volumes and only contain the products to be removed in relatively low concentrations.

Since these products and especially the phenols, which are often used as antiseptic products, have the property To destroy all organic ferments, it is not possible to purify the coking plant wastewater naturally carry out a biological degradation of the contaminating components. Special treatment is therefore necessary.

Concentration of these contaminating products, for example by distillation, to reduce the amount of material to be burned Volume does not appear economically advantageous, as the coking plant wastewater contains a number of contaminating products, such as Ammonia and certain phenols contain, which have a volatility comparable to the volatility of water, see above that these products are found both in the steam and in the concentrate, so that ultimately all of the water, that is, the liquid and vapor that must be supplied to the combustion treatment.

The present invention is a solution to this problem by providing for the case of the coking plant wastewater an increase in the Concentration of the polluting products of those to be burned

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Liquid in such a way enables the device cost on the one hand and the operating costs on the other hand can be kept within reasonable economic limits.

The inventive method now consists in that one Wastewater after adding a caustic alkali (caustic alkali) by a partial evaporation treatment with washing effect (stripping or stripping effect) of volatile products and in particular freed ammonia, the liquid obtained is distilled to form a concentrate, the vapor being passed through Passing in a caustic alkali washes, and the mineral salts and water are removed from the concentrate before making the burns organic materials if necessary.

Since all volatile materials and especially ammonia are removed by the pretreatment, it contains by evaporation Liquid to be concentrated as volatile products only phenols, which can be removed by washing with soda or sodium hydroxide solution be retained if they are at any of the evaporation stages be vaporized. Thus, the distillates of each of these stages only comprise practically pure water.

In order to keep the amount of caustic alkali used, for which soda or sodium hydroxide is used in practice, low and To reduce the harmfulness of the waste ultimately to be discharged, the addition of the alkali to the waste water on the Neutralization of these waters is limited, that is, to the displacement of the ammonia bound by the strong acids. In fact, the salts of ammonia and weak acids are volatile and can be destroyed directly by burning.

As soda or sodium hydroxide one can use those materials, which have already been used to wash the vapors formed during the distillation.

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The distillation device used is preferably a multi-stage one Device in which the soda or sodium hydroxide washing liquid is passed from one stage to the other, whereupon this Washing liquid is then conveyed to the inlet of the sewage to make them alkaline in a controlled manner.

In this way, the phenols, which tend to evaporate during the distillation, are always replaced by the soda or sodium hydroxide retained and returned to the concentrate.

The concentrate obtained in the distillation is concentrated. In this way one gets one hand depending on the applied Degree of evaporation of a dry product or slurry made up of the organic materials and the inorganic ones Salts, which are treated with a solvent for the organic materials, in order to filter off the mineral salts separate from organic materials; and on the other hand fumes.

The concentration of the salt solution obtained in the distillation can either be done in an evaporator, for example a rotary evaporator, take place, resulting in a dry product, or can be done in a crystallizer, whereby one a porridge or syrup is obtained, the two products obtained consisting of the salts and the organic materials.

The crystallizer used in the second embodiment can either independent of the multi-action evaporator in which the distillation occurs, or the final stage of this Represent facility.

The dry product or slurry is treated with a solvent for the organic materials, for example toluene. The mineral salts are then separated off, which are predominantly sodium chloride and sodium sulfate in dry form. The recovered sodium chloride can be used in

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in industry, for example for regeneration of ion exchange resins.

The liquid containing the organic materials is distilled to separate the solvent which is recycled while the organic materials are burned or mixed directly with the tars.

The liquid resulting from the concentration of the distillation The vapors formed can be completely or partially burned or mixed with the vapors emanating from the evaporator originate with multiple effects.

Since the mineral salts and water have been removed from the concentrate prior to incineration, they remain as burners Materials only organic materials, especially phenols. As a result, it may be advantageous to use some or all of the amount of the vapors resulting from the concentration to be introduced into the combustion device in order to reach the combustion temperature of the Regulate phenols.

The amount of steam that is not used for this can be used directly the vapors emerging from the multi-action evaporator are mixed, which are then condensed and before being discharged into the Sewer systems are treated with activated charcoal.

The advantages of the method according to the invention are as follows: The volume of the incinerator is considerably reduced since it only serves to burn the phenols. on the incinerator can even be dispensed with entirely if the organic materials are removed after separation the mineral salts mixed with the tars. Since the amount of materials to be burned is small, will the amount of fuel required is greatly reduced. The washing or filtering of the incinerator escaping exhaust gases is not necessary. The recovered sodium chloride can be sent to industrial

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Turn to be fed.

According to a first embodiment of the method according to the invention the concentrate exiting the multi-action evaporator is first treated with a solvent for the organic materials. The salt solution freed from organic materials is then separated from the organic one Fluid containing materials. The latter liquid is treated by distillation in the same way as described above, in order to separate the solvent then recirculated from the organic materials, which then either burned or mixed with tars.

The saline solution can:

Either they can be drained directly into a river if they have one

has a tolerable sodium chloride content,. ...

or evaporated in a vaporizer to recover the dry mineral salts and give vapors that are directly with the vapors coming from the multi-action evaporator are mixed,

or be evaporated in two stages in such a way that pure sodium chloride is obtained in the first stage in 80% of the total amount the amount corresponding to the salts and in the second stage wins the rest.

According to a second variant, the distillation residue is treated in such a way that the concentrate obtained during the separation of the mineral salts is either during the treatment or afterwards decanted in order to separate the oily substances floating spontaneously on the surface from the salt phase, the latter with a suitable absorbent, e.g. activated carbon, treated to remove the dissolved organic materials.

Since the majority of organic materials are due to the Evaporation resulted in a reduction in volume and an increase in the salt content, which lowers the solubility of the organic materials Can be decanted, the consumption of activated carbon is low.

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On the other hand, the treated water is not through the solvent contaminated for the organic materials and can therefore be discarded directly without separating off the solvent.

The two process variants can also be combined.

Further advantages, embodiments and objects of the invention result from the description of the invention referring to the drawings.

1 illustrates a first embodiment of the method according to the invention.

The wastewater is fed via line 1, which is via the Line 7b in the stripping column 2 is supplied with soda or sodium hydroxide. The ammoniacal distillate leaves this column via line 3. The wastewater subjected to the stripping treatment are then transferred via line 4 to the multi-action evaporator 5, and via line 7 to soda or sodium hydroxide is introduced. The vapors resulting from the distillation are condensed and then in the device 6 treated with activated charcoal.

The concentrate emerging from the multi-action evaporator is transferred to the evaporator 9 via line 8. The ones from the Vapors emerging from evaporator 9 via line 10 are burned in combustion device 11 in this embodiment, The dry product obtained after concentrating the concentrate is transferred via line 12 into a mixing device 13, in toluene, a solvent for the organic materials, is added to it via line 14. The solution obtained is filtered in the device 19, from which the crude mineral salts are withdrawn via the line 15.

The solution of the organic materials in toluene is distilled in the column 16, wherein the recovered toluene is removed via line 17 and recycled via line 14,

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while the organic materials via line 18 into the Combustion device are introduced.

Fig. 2 illustrates a second embodiment of the method according to the invention.

The wastewater is fed via line 1, which is via the Line 7b in the stripping column 2 is supplied with soda or sodium hydroxide. The ammoniacal distillate leaves column 2 via line 3. The wastewater is after the stripping treatment transferred via line 4 to the multi-action evaporator 5, which supplies via line 7 with soda or sodium hydroxide will. The vapors produced during the distillation are condensed and then treated with activated carbon in the device 6.

The concentrate obtained in the multi-action evaporator is transferred via line 20 to a liquid / liquid extraction column 21 introduced. The concentrate containing only the mineral salts is fed via line 22 into the first crystallization stage 23 and then via line 22b into a second Crystallization stage 24 promoted.

The resulting in the crystallization devices distillates are withdrawn via lines 25 and 26, with the from the Evaporator with multiple effects of emerging distillate combined and treated with activated charcoal. They can be burned if necessary will.

The mineral salts resulting from these two crystallization stages are withdrawn via lines 27 and 28.

Those in liquid / liquid extraction and the first crystallization stage Accruing concentrates can be discarded if necessary.

The solvent loaded with organic materials leaves the

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Liquid / liquid extraction device via line 29 and is introduced into a column 30, from which the solvent is drawn off via line 32 and into the liquid / Liquid extraction column 21 is returned. The organic materials leave the column 30 via line 31. You can either be burned or mixed with tars.

The method according to the invention is particularly suitable for treatment of wastewater containing phenols, ammonia compounds and mineral salts, i.e. mainly for the treatment of Coking effluents.

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Claims (12)

ER MEER ■ MÜLLER ■ STEINMEISTFiI 2 5 1 A δ 6 2 (ET) 7132/37 jQ - 10 - Claims Process for the treatment of waste water containing phenols, characterized in that the wastewater is mixed with a caustic alkali freed of volatile products by a partial evaporation treatment with washing effect, the liquid obtained distilled, washing the steam by passing it into a caustic alkali, and the mineral salts and the Water is removed from the concentrate obtained in the distillation before the organic materials are optionally removed burns. 2. The method according to claim!, Characterized in that that the caustic alkali is added to the waste water in such an amount that the obtained Mixture is chemically neutral. 3. The method according to claim 1 or 2, characterized in that the waste water is the solution of the caustic alkali used for washing by blowing in the steam. 4. The method according to any one of claims 1 to 3, characterized characterized in that the vapor formed during the distillation condenses and then treated with activated carbon will. 5. The method according to any one of claims 1 to 4, characterized marked that sodium hydroxide is used as the caustic alkali. 609824/0887 TER MEER · MÖLLER ■ STEINMEIS i FF? 2,514 86 6. The method according to any one of the preceding claims, characterized in that the mineral salts the concentrate by fully or partially evaporating the concentrate, treating the product obtained removed with a solvent for the organic materials and filtering off the mineral salts. 7. The method according to claim 6, characterized in that that the liquid containing the organic materials is distilled, the solvent distilled off recycled and the separated organic materials burned. 8. The method according to claim 6, characterized in that that the liquid containing the organic materials is distilled, the solvent distilled off recycled and the organic materials mixed with tars. 9. The method according to any one of the preceding claims, characterized in that when the concentration The resulting vapors are burned and used to regulate the combustion temperature of the phenols. 10. The method according to any one of the preceding claims, characterized in that the evaporation of the concentrate is mixed directly with the vapors formed during the distillation. 11. Modification of the method according to claim 6, characterized in that it is done during the distillation formed concentrate treated with a solvent for the organic materials containing the mineral salts Separates solution from the liquid containing the organic materials, which wins the mineral salts by evaporation the liquid containing organic materials is distilled TER MEER ■ MÜLLER ■ STEINMEISTER? R 1 and if desired, burns the organic materials. 12. Modification of the method according to claim 6, d a d u r ch gekennz e rejects that one after the separation the mineral salts accumulating concentrate either during the treatment or afterwards decanted to remove the oily substances, which swim spontaneously on the surface of the salt phase, to separate, and the salt phase with a suitable absorbent, Treated like activated carbon to remove the dissolved organic materials. 609824/0887 Blank page