SU1599312A1 - Method of processing waste water containing methyl acetamide and isobutyl alcohol - Google Patents

Abstract

The invention relates to the processing of industrial wastewater according to the integrated waste-free technology by adsorption, extraction and can be used in the production of synthetic fibers for the treatment of wastewater containing dimethylacetamide (DMAA) and isobutyl alcohol / CHD /. The aim of the invention is to increase the degree of water purification with simultaneous disposal of purified water, DMAA and IHD while simplifying the process. To carry out the process, waste water is treated with activated carbon, the absorbed substances are extracted from spent coal with two portions of chloroform, while the first extract portion is recycled through the coal to remove 90-94% by weight of the absorbed amount of substances, is distilled on IHD, DMAA, chloroform, distilled chloroform is used in the next cycle in the second portion, and the second portion in the first cycle is used in the next regeneration cycle as the first, the active carbon is treated with water vapor, from the resulting condensate The organic phase was isolated, which is attached to the chloroform was distilled off and the aqueous phase filtered through a bed of active charcoal additional column. 1 hp ff, 2 tab.

Description

The invention relates to recycling. KE industrial wastewater by adsorption and extraction I: can be used in the production of synthetic fibers for the treatment of wastewater formed during washing of fibers containing dimethylacetamide (DMAA) and isobutyl alcohol (IHD).

The purpose of the invention is to increase the degree of wastewater treatment with simultaneous disposal of the extracted substances - DMAA, IHD and purified water while simplifying the process of processing.

For carrying out the process, the waste water is treated with activated carbon and then used in production at

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After washing the fibers, the absorbed substances are extracted from waste coal with two portions of chloroform, the first portion of the extract, obtained by recirculating through coal to 90–94 wt.% absorbed amount, is accelerated by isobutyl alcohol, dimethyl acetate - amide and chloroform, the second portion of the extract of the act is used as the first portion in the next regeneration cycle, the active carbon after extraction is treated with water vapor, the organic is a layer from the resulting condensate, which is attached to tognannomu chloroform, and the aqueous portion was filtered through a layer of condensate active charcoal column to further recover dissolved chloroform. The treatment with carbon vapor is carried out at 13b-150 ° C and the steam supply intensity is 0.3-0.6.

Unlimitedly soluble in water, DMAA is adsorbed by activated carbon with a sufficiently high selectivity. The limiting adsorption capacity of the active carbon from a mixture of DMAA and IHD (2.5: 1), corresponding to the content of these substances in the waste water produced by the JQ fiber, is for DMAA. 1.55 mmol / g (134.5 mg / g, 13 wt.%), For IHD 0.9 mmol / g (66.6 mg / g, 6.7 wt.%).

The use of chloroform as an extractant provides almost complete (95-96 Vac.%) Extraction of components from water.

The advantage of chloroform as eluent DMAA and IHD is also in the fact that; when distilling off chloroform from the extract, there is practically no transfer of distilled substances into the distillate (DMAA content is 0.01%, IHD is up to 0.1%), and also neither dimethylacetamide, nor isobutyl alcohol from solutions in chloroform is adsorbed by coal (in a wide range of concentrations), which makes it possible to reuse recovered chloroform, as well as recirculate the same portion of chloroform through a carbon column for the maximum extraction of DMAA and IHD .

In addition, chloroform as an eluent for creating a practically wasteless technology of wastewater treatment from. DMAA and IHD has significant advantages over other organic compounds.

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builders. From the water condensate formed during the processing of coal saturated with chloroform, with steam, chloroform is easily separated thanks to a clear phase separation and reused.

Chloroform dissolved in the aqueous phase of the condensate is absorbed by the active carbon in an additional column, from where it is distilled off. The absorption of chloroform by active carbon from water condensate makes it possible to utilize all of the chloroform and use purified condensate in production, which results in a loss of technology.

The method is implemented as follows.

Waste water containing DMAA (836-850 mg / l) and. IBS (286-300 mg / l) is fed to the block of adsorbers, consisting of two devices filled with active carbon, working in series, of which the first water device works until saturation, and the second - until the breakthrough into the filtrate of DMAA and IHD. The process is carried out until the breakthrough into the filtrate is 0.4 mg / l DMAA and 1 mg / l IHD, which corresponds to the MPC value of these substances. 1 kg of active carbon in the columns cleans 80.4-90.0 liters of waste water. The water purification rate is 99.9%. After the breakthrough of DMAA and IHD, the adsorber is first disconnected for regeneration along the water course, the second adsorber is placed first along the water course, and an adsorber with fresh coal (reserve) is connected to it. For regeneration of the adsorbent, chloroform is fed to the adsorber with spent coal and filtered through a layer of coal at a rate of 1 hour. The total volume of chloroform for regeneration is 2 m per 1 m of coal loading in the column. This value is minimally necessary for the recovery of DMAA and IHD; Chloroform with desorbed substances is collected in two portions. The first portion of chloroform is recycled through the column until 90-94 wt.% Of the adsorbed amounts of DMAA and IHD are recovered and sent to the distillation cube, where chloroform is distilled at 58 ± 2 ° C. The content of DMAA in the distilled chloroform is 0.002-0.005%, and the IBS 0.1 t - 0.14% and it is used in the next cycle as a second batch.

The second portion of chloroform in the first cycle is passed through active carbon in a column containing 6-10 wt.% DOAL

and IHD, at the same rate, and after filtration through active carbon, are collected and used in the next cycle as the first batch of extractant.

To remove chloroform from active carbon, water vapor with a temperature of 130 and a flow rate of 0.45; tO, 15 kg / m2 s in an amount of 6.6 kg / kg of coal (5% of the volume of purified water) is passed through a layer of coal. After chloroform is extracted with steam, the adsorption column is recycled and the waste water is again filtered through active carbon.

The water vapor condensate is collected in a phase separator, from which chloroform is pumped to the chloroform dosing unit, and the condensate is sent to an additional adsorption clone to extract dissolved chloroform from it (5-7.3 g / l). The capacity of the coal in chloroform is 18 us. The condensate purified from chloroform is connected to the water used in production.

The bottoms from the still are sent to a vacuum distillation, from which, as a result of vacuum distillation, chloroform and IHD are sent to separate receivers, and BPAA remaining in the lower part of the apparatus is collected separately. As a result of vacuum distillation, 120-125 g of chloroform are obtained per 1 kg of coal, 33-34 g of IHD per 1 kg of coal.

Example: Wastewater containing 036 mg / l DMAA and 286.4 mg / l CHD is filtered successively through two vertical columns filled with active AG-3 charcoal at a speed of 3 m / m h. The height of the carbon layer in each column 76 cm, the mass of coal and the volume of loading in each column are equal to the corresponding

Apply 129 g and 263.1 cm

Before the breakthrough of DMAA and IHD (equal to the MPC), 17l of waste water is filtered through active carbon. During the work of active carbon in the first column absorbed 10,427 mg of DMAA and 4,676 mg of coronary artery disease.

The first column is turned off for regeneration, in the implementation of which two portions of chloroform, 263 MP each (392 g) each, are passed through the waste coal at a speed of 1 m / m-h. The first portion of chloroform is recycled through the layer of active carbon to extract 9.645 g (92.5 wt.%

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DMAA and 4.356 g (93.15 wt.%) IHD, after which it is removed from the cycle.

The remaining 0.782 g, (7, .5 wt.%) DMAA and 0.32 g (6.85 wt.%) IHD are extracted with a second fresh portion of chloroform (1 m / m of coal loading).

Carbon vapor treatment is carried out at 110 ° C, 850 ml of condensate is withdrawn, which corresponds to 5Z of the volume of purified water. In the separating funnel, the lower layer of condensate. (Chloroform) in an amount of 33.5 g is separated from the upper layer (a solution of chloroform in ts water with a concentration of 4.51 g / l). This solution is passed at a rate of 3. h through a layer of active carbon in an additional column in which there is 130 g of active carbon AG-3. In water, there is no exit from the additional column, chloroform is absent.

Chloroform is distilled off from the first portion of the spent chloroform solution at 58 ± 2 C, 250 ml (372.5 g) of chloroform are obtained, which are used in subsequent cycles, and the bottom residue

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sent for vacuum distillation. After vacuum distillation of the bottoms, 15.8 g of chloroform, 4.32 g of IHD and 9.76 g of DMAA are obtained. The degree of utilization is: for CHD U2.4%, for DMAA 93.6%.

In order to achieve the maximum degree of extraction from coal adsorbed by DMAA and IHD with a minimum amount of extractant, repeated recirculation of chloroform through the developed active carbon is necessary. So, are given in table. 1, the data show that the recovery rate of DMAA and IHD is 90-93%, achieved as a result of 3-4 times recirculation through the coal of the first portion of chloroform.

This mode of extraction of adsorbed substances ensures the maximum degree of use of the extractant and the utilization of recoverable substances in the treatment of waste water. A decrease in the degree of extraction of DMAA and IHD with a chloroform below 90% leads to a decrease in the efficiency of the extraction process. In tab. 2 shows the results of a multi-cycle installation of the proposed technology. 5 Process parameters: mass of coal 129 g; dimethylacetamide and isobutanol concentrations are 836-850 and 286-300 mg / l, respectively; filtration rate 3 .h; chloroform volume for regeneration 2 coal charges; multiple recirculation of the first portion of chloroform (1 coal) through active carbon until 90% of the adsorbed DMAA and IHD are recovered; steam temperature for distilling off chloroform; steam consumption for regeneration of coal from chloroform is 6.6 kg / kg of coal (5% of the volume of purified water); steam flow rate of 0.4 s. From the data presented in Table 2, it can be seen that the capacity of coal in the process of its multi-cycle operation is restored almost completely (by 97–100% relative to the value of the capacity of coal in the first. Cycle). The amount of utilized DMAA and IHD in relation to the amount of absorbed substances is 92-95%.

The efficiency of the method is provided at a temperature of water vapor of 130-150 ° C and at an intensity of its supply of 0, 30, 5.

It is economically and environmentally advisable to supply water vapor to the adsorbent with the formation of condensate up to 10% of the volume of purified water. However, in the proposed method, the temperature treatment mode with steam ensures complete recovery of the adsorption capacity of the active carbon with the formation of 5% condensate.

Reducing the temperature of water vapor (up to 120 ° C) at a steam intensity of 0.5 seconds requires for increasing the capacity of the active carbon an increase in the volume of condensate to 15% of the volume of purified water.40

An increase in the temperature of water vapor (and higher) is impossible due to the decomposition of chloroform.

A decrease in the steam supply rate (0.2) at a temperature of 45–150 ° C also requires that the recovery of the coal capacity causes an increase in the condensate volume to 13%, and an increase in the steam supply rate (0.75) leads to a decrease in the chloroform content .and, as a result, to obtain large volumes of condensate that require cleaning on an additional adsorption filter.

Thus, the minimum volume of condensate 5 while maintaining the efficiency of the process of extracting adsorbed chloroform from coal is achieved in the temperature range of water vapor.

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130-150 C and the intensity of its supply to the adsorbent 0.3-0.5.

The proposed method provides complex processing of wastewater produced by synthetic fibers, which results in deeply purified water containing DMAA and IHD at the MPC level (0.4 mg / l for DMAA and 1.0 mg / l IHD), while desalting remains water, which makes it possible to reuse it for washing the fibers, and the products extracted from the wastewater are disposed of as commercial products, while these substances are destroyed by a known method.

The method ensures the creation of a waste-free technology due to the repeated use of the used adsorbent — regenerated active carbon and extractant — distilled chloroform.

Claims (2)

The advantage of this method is that the almost complete recovery of coal capacity is achieved when receiving condensate water vapor to only 5% of the volume of purified water. Claim 1. Method of treating waste water containing dimethylacetamide and isobuicol, tilovy alcohol, characterized in that, in order to increase the degree of water purification with simultaneous disposal of purified water, dimethylacetamide and isobutyl alcohol while simplifying the process, waste-water is filtered in two steps through active carbon, the processed carbon is treated with two portions of chloroform, with the first portion being recirculated many times until 90-94% of the absorbed substances are recovered, followed by the regeneration of chloroform, dimethylacetamide and isobutyl alcohol by distillation and using distilled chloroform as the third portion in the next cycle, and the second portion of chloroform after using in the first cycle is fed to the next cylinder as the first portion, the active carbon is treated with water vapor, the organic phase is separated from the condensate obtained and added to the distilled chloroform, and the aqueous phase is filtered through the active angle 2. The method according to p. 1, characterized in that the treatment with carbon vapor is carried out at a temperature of 130-150 C and a steam supply rate of 0.3-0.6.