CS269582B1 - Method of waste waters purification - Google Patents

Abstract

Sewage treatment containing one Cg aromatic hydrocarbon. to C, or a mixture of aromatic hydrocarbons with Cík-Cg chlorinated hydrocarbons, is a liquid-liquid extract wherein the extracting agent is an aliphatic hydrocarbon or a mixture of predominantly aliphatic hydrocarbons having a boiling point of from 20 to 350 ° C; The mole ratio of the extractant to the purified water is 1: 2 to 50. The extraction agent may also contain non-toxic antioxidants (2,4-di-tert-butyl-4-methylphenol). The phases are separated while the extract is generally led to the recovery of the extractant.

Description

CS 269 592 B1 r

BACKGROUND OF THE INVENTION The present invention relates to a process for the purification of waste gases containing at least one chlorinated hydrocarbon C 1 to C 8 and / or at least one C 8 to C 8 aromatic hydrocarbon by extraction using technically available and easily recoverable extraction units. Chlorinated hydrocarbons, as well as aromatic hydrocarbons, can be present in the effluents both in dissolved form and in enulphated form; in extreme cases, a more or less layered layer can be formed on the waste water level. These are needed from the effluent, at least to a considerable extent, not so much from the technical-economic (recovery of hydrocarbons and aromatics) as environmental factors. Chlorinated hydrocarbons, such as 1,2-dichloroethane, dichloroethylenes, chloroform, carbon tetrachloride, as well as trichlorethylene and perchlorethylene, and mainly aromatic benzene, sd are relatively strong-toxic and are only very slowly biodegradable. To a relatively widespread process of refining wastes from chlorinated hydrocarbons, adsorption is either only on activated carbon or, in addition, on synthetic ion exchange resins, such as Amberlite XAD-4, followed by aqueous steam or air desorption / Dummer G., Sdhmidhammer L. : Chem. Ing. Tech. 56, 3, 242 (1984); Chem. Industrie, 16, 5, 294 (1984); Grtnwald A .: Oil and Coal 22, 46 (1987); Kočetkova R. P. et al .: Chim.promyšl. δ. 3, 148 (198, 4)]. However, the problem is the relatively low capacity of the adsorbents. There is also a good situation in the combination of activated charcoal adsorbents and wastewater biological treatment (Stover E. L. et al. Ozone Sci. Ihg. 1985, 7 (3), 195; deposited of the invention NSR 3,418,074; me p. pat. 86-200 337; Chem. Abstr. 106, 39510 (1987). The pulverized coal in the activated biological sludge is captured by toluene and 1,2-di-chloroethane, with toluene being biodegradable. Ozonization of purified water allows biodegradation of the hydrocarbons thus captured. Alternatively, the absorption on the active eye is combined by adsorption on Fuller Clay or other microporous sorbents (Saburina E.O. et al.). fiz. chim. 60 (12), 3038 (1986)]. These methods are thus more suitable for "refining." Remarkable but technically and energy-intensive is the desorption of chlorinated hydrocarbons from the effluents by desorption / Petrova N. et al., Chim.promyšl No. 3, 149 (1982) U.S. Pat. No. 4,544,483, Tomita Sh., Et al., Chem Abstr. 104, 155583 g (1986, respectively, by stripping, usually by air. Interesting is also the extraction of 1,1,1-trichloroethane and chloroform from effluent). boiling point paraffinic fraction having a boiling point of 180 DEG-220 DEG C. (Austrian Pat. No. 373,858 (1984)), as well as extraction using extraction agents such as typical cyanobacterial organic solvents (Earhart J. Co., Chemical Engng.). Progression (CEP) 2 67 (1977), which, however, is technically difficult to regenerate and additionally relatively soluble in water, then oxidation with air at 500 ° C in a limestone-filled reactor, further oxidation with air or ozone at about 20 ° C with the presence of ferrous sulfate or hopcalite / Sidorenko J.N. others: Doc. AN Ukraine SSR, ser. B, Geol. Chem. Biol. Nauki 10 (1982); Optionally, a combination of oxidation of organic matter in water with ozone and ultraviolet radiation with hydrogen peroxide as catalyst or initiator (Mašten S.J. et al.) Ozone, Sci. Big. 8 (4), 339 (1986)]. However, the energy intensity of these methods is evident, and in cases where there is an increase in the presence of non-radical inhibitors in wastewater, the low refining efficiency is low.

However, according to the invention, a process for the purification of wastewater containing at least one aromatic hydrocarbon C8 to C0 or a mixture of at least one aromatic hydrocarbon with at least one chlorinated hydrocarbon C12 to C8 is effected by extraction of the hydrocarbonaceous material such that the liquid is the liquid-liquid of the least one-stage extraction. at least one aromatic hydrocarbon or a mixture of at least one aromatic hydrocarbon with at least one chlorinated hydrocarbon, providing an aliphatic hydrocarbon or a mixture of predominantly aliphatic hydrocarbons from a boiling range of 20 to 350 ° C and / or dialkylbenzenes having a boiling point of 180 to 350 ° C; % additive to purified water ratio of 1: 2 to 50, optionally 0.1 to 5% by weight. antio- 2 CS 269 582 B, xidant, as 2,6-diterc. butyl 4-methylphenol, 2,6-dimethylT-4-alkylphenol and tris- [2- (1-phenylethyl) phenyl] phosphite, followed by liquid phase separation. In this case, the extract leads to regeneration of the extraction agent. An advantage of the method of purification of waste effluents according to the invention is the high partition coefficient, respectively. high refining efficiency of extraction agents, the possibility of extracting not only chlorinated but also aromatic hydrocarbons and even other admixtures of other organic substances, such as propylene chlorine-diene, dichlorodiisopropyl ether, propylene oxide, etc., from the waste water in one stage. and easy regeneration of both the extraction agents and the chlorinated and aromatic hydrocarbons. Last but not least, the fact that such refined water can generally be released into streams or retention tanks without further treatment.

According to the present invention, waste water containing at least one chlorinated hydrocarbon, such as 1,2-dichloroethane, 1,1,1-trichloroethene, tetrahydroethane, pentachloroethane, hexachloroethane, dichlorethylene, vinylidene chloride, trichlorethylene, perchlorethylene, chlorprene, mixtures, chlorinated hydrocarbons from the production of dichloroethene and vinyl chloride, chloroprene, chlorofluorolefins. Then chloroform, methylene dichloride, tetrahloromethane, such as chlorofluoromethane. Further, at least one C8 to C8 aromatic hydrocarbon, especially benzene, toluene and xylenes, ethylbenzene, trimethylbenzenes and styrene, may be present. Mixtures of chlorinated hydrocarbons with aromatic compounds are frequently present. Last but not least, waste water may also contain admixtures of other organic compounds such as propylene chlorohydrin, dichlorodiisopropyl ether, chloromethyl ether, olefin oxides, propylene glycol, dipropylene glycol, and other organic compounds, especially acidic and chlorocarbonated organic compounds. For reasons of the easy isolation of the extracted chlorinated and aromatic hydrocarbon extracts, as well as the recovery of the extraction agents, it is preferable to use the so-called extracted chlorinated and aromatic carbon by 20 to 200 ° C, most preferably 40 to 100 ° C. A suitable extraction agent is petroleum ether, the further fractionation of light primary gasoline or aliphatic primary gasoline. Then mainly the automated kerosene fraction, but also the fraction of diesel fuels, respectively. light oil oil. Particularly suitable are n-alkanes obtained by stripping off petroleum fractions by adsorption methods, i.e. by means of molecular sieves, but also hydrocarbon fractions from hydrocracking products of petroleum vacuum distillates and the like.

Extraction is performed using conventional extraction equipment.

Separation of the liquids - extract and refined water (raffinate) is most effected by stapling or centrifuging.

As a rule, the extract results in the isolation of the extracted aromatic and chlorinated compounds and the recovery of the extraction agents, usually by distillation and rectification. In the case of the use of high boiling point hydrocarbons (but also solidification) as extraction agents, selective crystallization can also be used to regenerate them.

If the raffinate, i.e. the refined wastewater is virtually completely freed from the feed, it can be increased by adsorption, e.g., on activated carbon, followed by biodegradation, possibly also by oxygen, oligomers of oxygen and ultraviolet radiation. , further by adsorption on hydrophobised aluminosilicate builders, with biological refinement and so on.

However, the effluent purified according to the present invention is generally purity-free for water streams or retention tanks. 269 (582 B! 3) In the case of two quantities of extracted hydrocarbons 2, and also to prevent corrosion of the equipment by effluents and extracts containing chlorocarbons, it is advisable to add non-toxic antioxidants to the extraction agents, such as 2.6 di-tert-butyl-p-cresol, 2,6-dimethyl-4-alkylphenol, tris- (2,4- (1-phenylethyl) phenyl) -fos-ap.

The refining process according to the invention is. it can be performed continuously, semi-extruded and continuously. Further details of the method as well as other advantages are apparent from the examples. Example 1

Water was used for the extraction from a plant object containing 0.2138 wt. 1,2-dichloroethane (DCE) and 0.019 wt. of benzene, 27.2 g of this effluent was charged to a separatory funnel and 2.99 g of a petroleum ether fraction was added thereto, with a distillation range of 20 to 40 ° C. The separating funnel was closed with a good ground stopper and the mixture was vigorously shaken for 15 min. It was then left to sediment at 20 ° C for 2 hours. A sample was taken from the bottom aqueous phase and analyzed by gas-liquid chromatography ((Chrom 4) using a 3 mm column, 3,700 mm in length, filled with a NAW Chromaton, A 10% FFAP anchored phase is applied, nitrogen at 140 ° C. The determined DCE content of the aqueous phase of the extraction is 0.0393% by weight and benzene 0.0012% by weight. the hydrocarbon phase was determined from a balance of 1.64% by weight and benzene by 0.1670% by weight.

Partition coefficient in% by weight. DCB in hydrocarbon phase; DCE in Water Phase 4 ’? and benzene = 139, Example 2

In a similar manner to Example 1, a mixture containing 0.4 wt. Dcevo water. To the extraction funnel was added 27.0 g of said DCE mixture and 3.0 g of petroleum ether. After extraction, 0.0717 wt% was determined in the aqueous phase. DCE.

The DCE content of the hydrocarbon phase was 2.8719, which corresponds to a partition coefficient of 40.05. Example 3

Water from the plant object of composition as in Example 1, in an amount of 27 g, was extracted with n-alkanes C, -C, O at 3 g at room temperature. After separation of the phases, the aqueous phase contained 0.0364% wt. DCE and hydrocarbon phase 1.5723 wt. DCE.

Partition coefficient KpQg = 43.2. Example 4

The water of the plant object of composition as in Example 1, in an amount of 27.04 g, was extracted with alkanes at a rate of 3 g at room temperature. After phase separation, the aqueous phase contained 0.0366% DCE and a hydrocarbon phase of 1.573% wt. DCE. -Cient KDCE = 43 Partition Splitter.

Claims (4)

Example 269 Waste water containing 0.087 wt. trichlorethylene was introduced into the separating funnel in an amount of 27.09 g and the 1-alkene-Ο, θ in an amount of 3.00 g was extracted. trichlorethylene and hydrocarbon phase - extract 0.6812% trichlorethylene. The partition coefficient KpQ = 61.4. Example 6 Water containing 0.03 wt. of toluene in an amount of 54.05 g was extracted with 0.62 g -alkene C 4 -C 6. It contained 0.00195 wt. toluene and extract 0.2512% by weight of toluene. Partition coefficient kTqL = '2 ^. Example 7 1 Water containing 0.03 wt. toluene (54.05 g) is extracted with 6.00 g of refined dodecylbenzene distillation residue, boiling point 320 DEG-350 DEG C., solidification temperature -52 DEG C., containing mainly dialkylbenzenes with alkyls and diphenylalkanes (phenyls). on the alkane chains C 1 to C 6) and with an admixture of 0.2 wt. 2,6-di-tert-butyl-4-methylphenol and 0.05 wt. tris- (2,4- (1-phenylethyl) phenyl) phosphite as antioxidants. After extraction, the raffinate contains 0.00051 wt. % toluene and extract 0.2601 wt. toluene. Under otherwise similar conditions, but at a refined water temperature of 0.3 ° C, the raffinate contains 0.00021% by weight. toluene and extract 0.2673 wt. toluene. SUBJECT OF THE INVENTION * CLAIMS 1. A method for disintegrating effluents containing at least one aromatic hydrocarbon C8 to C8 or a mixture of at least one aromatic hydrocarbon with at least one chlorinated hydrocarbon C1 to C8, by extraction with hydrocarbons, characterized in that it is at least one stage from the waste water. by liquid-liquid extraction, extracts at least one aromatic hydrocarbon or a mixture of at least one aromatic hydrocarbon with at least one chlorinated hydrocarbon, by the action of an aliphatic hydrocarbon or a mixture of aliphatic hydrocarbons boiling in the range of 20 to 350 ° C and / or dialkylbenzenes having a boiling point of 160 to 350 ° C. to distilled water 1: 2 to 50, optionally containing 0.1 to 5 wt. an antioxidant such as 2,6-di-tert. butyl 4-methylphenol, 2,6-dimethyl-4-alkylphenol and tris- [2,4- (1-phenylethyl) phenyl] -phosphite, followed by separation of the liquid phase, the extract being generally led to the recovery of the extracting agent. 2. A method of distancing according to claim 1, wherein the extraction is a mixture of hydroaliphatic hydrocarbons from a temperature range of 20 DEG to 170 DEG C., preferably 36 DEG to 125 DEG C., and / or alkanes having a boiling point of 220 DEG to 350 DEG C., preferably 240 to 300 ° C. 3. A method of spacing according to claim 1 or 2, characterized in that the extraction is a mixture of cycloaliphatic and cycloaliphatic hydrocarbons boiling at 100 to 350 ° C and / or dialkyl aromatic hydrocarbons boiling at 180 to 350 ° C, preferably a mixture of dialkylbenzenes with C 1 -C 6 alkyl and diphenylalkanes, which is a by-product of the electrolyte production. 4. A method according to any one of claims 1 to 3, characterized in that a mixture of at least one chlorinated hydrocarbon with an aromatic hydrocarbon is extracted from the waste water by the action of an aliphatic hydrocarbon or a mixture of aliphatic hydrocarbons boiling from the extracted chlorinated aromatic hydrocarbon. 20 to 200 ° C, preferably 40 to 100 ° C.