SU973487A1 - Process for purifying waste liquors from coke chemical production - Google Patents

Description

The invention relates to the treatment of wastewater from a coke plant, containing emulsified salt oil, resins, sulphides, phenols, benzene and other organic substances.

The known method of wastewater treatment of coke-chemical production, including water treatment with iron sulphate and filtration through filters loaded with quartz sand G11. The disadvantage of this method is the low degree of purification from organic matter and sulfides.

The closest to the invention to the technical essence is a method of wastewater treatment, which includes treating wastewater with permanganate and a peroxide substance in a alkaline medium in the presence of metal salts forming hydroxides and catalyzing the decomposition of the peroxide substance and subsequent filtration of the aqueous phase 2. The disadvantages of the known method there are high consumption of reagents for the purification of oil-, sulphide-containing wastewater and a low degree of purification from sulphides and clarification of water.

The purpose of the invention is to increase the degree of purification from sulphides and water clarification, as well as to reduce the consumption of reagents.

This goal is achieved by the fact that according to this method, the waste water from the coke-chemical production is preheated to 50-100 ° C, treated in alkaline medium with iron and manganese salts, blown with air until complete oxidation of sulfides and then treated with permanganate and hydrogen peroxide and then carried out filtering.

15

Filtration of the aqueous phase is carried out electrolytically and / i. Through a layer of granular sorbent.

When treating water heated to 50 ° C with first iron salts

20 and manganese are formed of insoluble, metal sulfides, to: which after the subsequent processing, the oxides are oxidized by oxygen in the air, as a result of which alkaline water is formed

Metalshlov 25 flocculent hydroxide, which surfactants oil and other impurities. When treating such water with hydrogen peroxide and permanganate, the latter is consumed only for

30 implementation of flotation of contaminating impurities in the foam phase, and the permanganate activates the decomposition of the peroxide substance. Water clarified in this way is purified from; non-floated impurities in the filtration process, and with electro-filtering a walkie-talkie, deep flotation of impurities from the flotation is achieved; due to their dissolution in oils, resin sorbed by flocculent particles of metals and oxides). Preheating of water to 50-100 ° C provides 95-100% oxidation of sulphides when they are contained in waste water above 1 g / l. With a decrease in wastewater temperature below, for example, to 40-20 ° C, the oxidation degree of sulfides decreases, for example, at 40 ° C to 93-90% and at 20 ° C to 87-88%. Increasing the water temperature above 100 ° C requires special equipment neither the cleaning process at elevated pressures, that syllable 1: o. Electrolytic and / or mechanical filtration of wastewater treated with reagents provides 90.5–98% clarity of purified water due to filtration of non-floated impurities, such as hydroxides and metal oxides; electro-flotation of destabilized dispersed impurities, such as oils, resins, anodic oxidation of impurities, sulfides, sorption of organic impurities granular backfill, such as benzene, phenols. Iron, manganese, copper nickel salts are used as metal salts, which provide high levels of wastewater cleaning from oils, sulphides and other impurities in the presence of permanganate and peroxide substances due to coagulation and simultaneous flotation of contaminants, while using predominantly salts of iron, manganese, as the most common and widely used: reagents. The implementation of electrolytic filtration of the aqueous phase during its settling provides simultaneous electroflotation of contaminants and thus simplifies the purification of water from emulsified oils and sulfides ;. Destabilized fine particles of oils and other impurities are floated to the surface of the aqueous phase in the settling chamber with bubbles of gas evolved on the electrodes as a result of the electrolysis of water - and decomposition of the remaining peroxide on the electrodes. Example. One liter of emulsified waste water from the brine absorption oil recovery solution (pH 9), containing 1.5 g of salt oil and tar, 138 mg of benzene, 14 mg of phenols, 0.4-1.1 g of sulfides, is heated to 20, 40, 50, 60, 80 and, with stirring, add 330 mg of ferrous sulphate (ferrous), 309 mg of manganese sulphate and purge with air until the water turns a dark color to light (yellow). Then 0.08 g of permanganate and 0.26 g of hydrogen peroxide are added. Shake the treated water vigorously for 1-3 seconds and stand. Formed throughout the volume of gas bubbles float impurities of water and foam phase. The clarification of the vrda is reached after 0.5 minutes. At the same time, the residual benzene content is up to 2-0 mg / l and phenol up to 3 mg / l. After electroflotation of waste water through mesh cathode and lattice anodic electrodes made of stainless steel or platinized titanium with openings of 0.1 mm and 3 or 10 mm in a grid with a cathode current density of 75 A / m and following filtration of water through an AR carbon layer -3 (layer height 5 cm, filter area 10 cm); odor and impurities of oil, benzene, phenols and sulphides are not detected. In the table you will find the indicators of water purification containing different amounts of sulphides.

0.4

50 60 0.4

. 97.0

100 99.0 100

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Claims (2)

Claim 1. A method for treating wastewater by-product of coke production, including treating water with permanganate and a hydrogen cross-salt in an alkaline medium in the presence of metal hydroxides ™ and subsequent filtration, characterized in that, in order to increase the degree of purification from sulfides and clarify water, as well as To reduce the consumption of reagents, 35c water is preheated to 5010O®С, then iron and manganese salts are introduced and purged with air until the sulfides are completely oxidized. 2. The method of pop. 1, characterized in that the filtration of the aqueous phase is carried out electrolytically and / or through a layer of granular sorbent. 45 Sources of information taken into account in the examination 1. Proskuryakov V.A., Schmidt L.I. Wastewater treatment in the chemical industry. Chemistry, 1977, p. 40-5-406. 2. USSR Copyright Certificate No. 791614, cl. C 02 F 1/24, 03/11/79.