CS258714B1 - Method of water treatment from the hydrogenation process - Google Patents

Abstract

A method of reducing tarry organic substances in waters from the hydrogenation process with a high content of water-soluble organic substances and water-soluble inorganic salts using a thickener and a coagulant by two-stage neutralization. In the first stage, at pH 7-8, chemical sludge is precipitated by the action of mineral acid, and in the second stage, it is subjected to dispersion of coagulant and thickening agent, at pH 5-5.5.

Description

258714

The present invention provides a process for the treatment of water from the process of hydrogenation contaminated with organic waters and dissolved inorganic salts.

One of the basic operations of sewage treatment from chemical plants of their clarification, which eliminates predominantly suspended and most colloidal particles. The principle of clarification is generally known and its essence lies in the addition of coagulating agents, usually aluminum salts, or those which, by hydrolysis, yield bulky precipitates. hydroxides after pH adjustment. These, like positive charged particles, allow colloidal particles to coagulate with a charge charge. As a result, separable flake suspensions are formed. In the hydrogenation process waters which are contaminated with inorganic water-soluble substances with a high concentration of 18-25% in addition to suspended organic particles, a two-stage process is used for the purification process when the insoluble particles are removed from the settler in the first stage. or clarifiers and filters, whereby the water from the hydrogenation process is depleted of the chemical sludge as a substantial contaminant component, with subsequent biological or thermal treatment at the second stage.

The application of a two-stage purification, typically withdrawn in cases where the alkaline waste water is contaminated with water-soluble substances of anorganic origin, in addition to the organic substances. In these cases, the presence of inorganic salts causes the precipitation of toxic organic substances after pH adjustment, but the high content of inorganic water-soluble salts causes over-precipitation of the precipitated organic substances, even with the addition of coagulant. As a result, there is no sedimentation but flotation, so that the settling device does not fulfill the expected effect. The particles are non-devices, penetrate into the drained water for biological purification, thereby making the pretreatment ineffective and CODCr reaching 22,000 mg. l_i and more.

Such high values cause the inhibition of microorganisms in the biological plant, thereby reducing its effectiveness, eventually causing a biological collapse of the plant. [0007] To date, solutions for solving the problem are solved by electrolytic methods using electronegative metals according to U.S. Pat. No. 3,806,435 or by contacting with a copolymer of alkene-vinylaluminate having a vinyl alcamate content of 15-40% according to DT2 409 348, as well as EN ΔΟ 208 064, based on waste water evaporation and CO2 bubbling. In the literature (Chimija i techn. Water 1985,7 / 1), electrochemical purification of nitro-containing effluents, amine products in the presence of Ni catalyst and in a professional journal (Chemical Industry 1983,33 / 4) are reported for the use of activated charcoal or active chlorine is the solution to the problem. Said processes require additional substances to be introduced into the purification process, possibly requiring adaptation of devices which allow electrochemical treatment, while some additives are economically unacceptable as well as corrosion problems. In the case of character-like leaders, which arise from the process of producing antioxidant as hydrogenation water, the application of the free neutralization and coagulation is ineffective, even in the case of the use of a ballast, due to the complexity of the system, since the effluents are heavily contaminated except inorganic salt and organic substances of a pit-like character. Accordingly, it is not possible to provide optimum pH for the coagulant and load function in the operating conditions. The desired pH range of 5.0-5.5 is technically unmanageable by the one-stage neutralization, since the sudden passage through the PH range of 8.0-6, 5 the system is not stable. There is a release of gaseous effluents and acidic character, which cause non-standard conditions for the optimal course of self-coagulation and load-bearing function.

However, it has been found that it is possible to provide a combined effect of the coagulant and the load factor with a sufficient effect of the invention, the principle being that water from the hydrogenation process contaminated with inorganic salts and organic substance-like substances by the action of dispersed load particles, characterized in that the water from the hydrogenation process is neutralized in the first stage to a pH of 7 by the addition of a mineral acid prior to the load and coagulant treatment, and the mixture is then dispersed in the presence of coagulant and the load dispersion at pH = 5.0-5.5 after the second stage the weight of the loaders being less than 250 microns.

The process according to the invention achieves that the precipitated sludge does not float but settles, does not pass into the clear phase. The efficacy of reducing organic matter is 40% against known processes, which is sufficient for the biological treatment plant to run.

Dolomite, calcite, zeolite, kaolin, perlite have proved to be useful as bentonite. Since the substances applied are of a coherent nature, they do not impair the quality of the hydrogenation process. The addition of the mentioned substances is minimal, affordable. The sedimentation rate of the sludge is sufficient, and gravitational settlers of the present designs or gravitational stacks may be used for the dispersed mixture. their replacements in this technological node by centrifuges, or by special filters or filter presses.

Claims (2)

SUBJECT 1. A process for treating water from a hydrogenation process contaminated with inorganic salts and pitch-like organic substances by dispersed weight particles, characterized in that the water from the hydrogenation process is neutralized in the first stage to pH 7-8 by a mineral acid before treatment with the weighting agent and coagulant. the mixture is dispersed in the presence of a coagulant and a weight dispersion dispersion at pH 5.0-5.5 after the second neutralization step. 2. The method of treatment of the hydrogenation process leads according to claim 1, characterized in that the particle size of the ballast is less than 250 μΐη.