SU1726012A1 - Apparatus for neutralizing reclaimed alkaline waste water with flue gases - Google Patents

Abstract

The invention relates to environmental protection and can be used in the process of water treatment at thermal power plants. The purpose of the invention is to save chemical reagent for the regeneration of Na-cation-exchange filters during water treatment by replacing the aqueous solution of this reagent with neutralized effluents and reducing the discharge of these effluents into the environment. The installation contains an apparatus for neutralizing alkaline waters, tanks for collecting acidic and alkaline drains connected to the apparatus by pipelines with metering pumps, a tank for receiving neutralized drains with a pH meter, a flue gas supply pipeline with a fan and a flow regulator, whose actuator is occupies a line with a pH meter output signal. The plant is also equipped with a clarifier for precipitating and withdrawing hardness ions and a soda-water preparation tank. 1 il.

Description

The invention relates to environmental protection and can be used at thermal power plants in the process of water treatment by ion exchange.

The closest in technical essence and the achieved result to the claimed technical solution is an installation for neutralizing alkaline wastewater with flue gases, containing an apparatus for neutralizing wastewater H-cationite and anionite filters, an alkaline waste collection tank connected to an apparatus for neutralizing through pipeline with a pump - dispenser, neutralized sewage receiving tank, equipped with a pH meter, flue gas supply pipeline with a fan and a flow regulator, actuator cat This is associated with the output of a pH meter signal.

The presence of a pH meter in the installation scheme allows one to automate the control and management of the neutralization process, however, the discharge of these effluents into the environment is preserved, which leads to additional consumption of fresh chemicals in the water treatment process and environmental pollution.

The purpose of the invention is to reduce the amount of effluent discharged into the environment and the possibility of using neutralized effluent to regenerate the Na-cation-exchange filter during water treatment.

The goal is achieved by the fact that the installation of the neutralization of alkaline waste water with flue gases, containing SO

ABOUT

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a parasite for neutralizing wastewater H-cation-ion and anion-exchange filters, an alkaline waste collection tank connected to an apparatus for neutralizing through a pipeline to a metering pump, a neutralized wastewater receiving tank equipped with a pH meter, a flue gas supply pipeline with a fan and an flow meter, the actuator of which is associated with the output of the pH meter signal, is equipped with a waste water clarifier for precipitating and removing hardness ions, a tank for preparing soda solution and an additional tank for acidic wastewater, the input of the clarifier is connected to the outputs of the acidic and alkaline wastewater collection tanks and the soda solution preparation tank, the latter is connected through the pump to the dispenser with the alkaline wastewater collection tank and the flue gas supply pipe, and with the entrance of this solution into the neutralization apparatus.

This allows the Ca + and MD2 + hardness ions to be completely removed from the water being produced and to use the resulting clarified solution, which is a mixture of sodium salts, to regenerate the Na-cation-exchange filters in the water treatment scheme instead of the sodium chloride used and thereby realize the savings of chemical reagent - that, and also to reduce dumping of sewage into the environment.

The drawing shows a schematic diagram of an installation for neutralizing alkaline wastewater with flue gases.

The installation contains an acid wastewater collection tank 1, connected via a metering pump 2 to an clarifier 3, an alkaline wastewater collection tank 4, connected via a metering pump 5 to a soda solution preparation tank 6 and in parallel with the clarifier 3, which in turn is connected at the outlet of the clarified solution with the apparatus 7 for neutralizing alkaline waters. At the outlet of the latter, a tank 8 is installed that receives neutralized wastewater with a pH meter 9. The installation also contains a pipeline 10 for supplying flue gases to the device 7 and a tank 6 with a fan 11 and a flow regulator 12. The pipeline is connected to chimney 13 Signal output from the pH meter is connected by line 14 to the actuator 15 of the flue gas flow controller 12. The neutralization apparatus 7 comprises an inner ring 16 and two annular manifolds 17 and 18 for dispensing the clarified solution and flue gases, respectively. The top of the apparatus 7 and the tank 6 for the preparation of the soda solution are supplied with droplet catchers 19. The gas outlet from the apparatus is connected

line 20 with tank 6. Between line 20 and pipe 10 there is a jumper with a shut-off device 21. Clarifier 3 is equipped with a pipe 22 for withdrawing sludge from it. The tank 8 is equipped with a line 23 for supplying clarified neutralized effluents to Na-cationite filters (not shown in the drawing). Line 23 is equipped with a pipe 24 discharge of excess water into the sewer.

The installation works as follows

The spent acidic solution after regeneration of the H-cationite filter enters the collection tank for acidic wastewater. The composition of the acidic effluents obtained during filter regeneration with a 1.5% H2S04 solution is as follows:

SN + 75-80 mg-sqv / l

Csa2h-90-93 mEq / l

Smd 4 15-30 meq / l

CNa 104-116 mEq / l

Szo42-260-300 mEq / l

The solution is fed by the dosing pump 2 into the clarifier 3, Alkaline drains from the tank 4 are fed there with the help of the dosing pump 5.

The composition of alkaline waters obtained during the regeneration of anion-exchange filters with 4% NaOH solution is as follows:

 MG-EKV / L

Dsdz 11.5-134 mg-eq / l

Cso 241-346 mEq / l

Cci 268-288 mEq / l

Szyuz2 27-28 meq / l

Sleep 300-340 mEq / l

From 1/3 to 1/2 alkaline wastewater is supplied to tank 6 for preparing a soda solution, where the excess alkali is first converted to soda by carbon dioxide contained in flue gases supplied through lines 10 and 20. According to the formula

20Н + 2С02 - 2РСОз

From the tank 6, the solution with soda enters the clarifier 3, where the formation takes place. precipitation and removal of hardness ions as a result of the following reactions

20H - -Md24 MDYN) 2;

HE NSOZ SOz2 + H20

C032 Ca2 + CaCOz vSi032 + Ca2r CaSiO

With a very low solubility of these salts: PRSOCOZ-2.9., PRMDON2 5 ,, nPcaSi03 6.6 10, they are almost completely precipitated and removed from clarifier 3 through pipe 22 in the form of sludge, which can be used after dehydration as raw materials for the production of building materials.

The clarified solution, which is a mixture of sodium salts: N and CI.

Na2SO4, NOZSO3 and a small excess of alkali, is fed into the apparatus 7 for neutralization through an annular distribution manifold 17. Flue gases containing the acidic components in the form of S02 are supplied to the dispensing annular distributor 18 located below it; ZOZ; C02. Flue gases float in the form of bubbles in an annular gap formed by the walls of the apparatus 7 and the inner ring 16. The bubbles carry the clarified solution into the apparatus through the collector 17. As a result, alkali and soda interact with the acidic components of the gas according to the formulas

2NaOH + S02 - N32S03 + N20

NaOH + ZOZ + Na2S04 - + H20

N32C03 + C02 + H20 2NaHC03

When this happens, the solution is neutralized to a pH value of 6.5-8.1. After apparatus 7, the solution can be used as a regeneration solution for the Na-cation-exchange filter, instead of a fresh aqueous solution of sodium chloride (NaCI), since it represents about 2% sodium salt solution (1.2-1, 4 No. 2504 0.6-0.8 NaCI; 0.04-0.06 NCHOz; 0.08-0.12 NaaSO). And only the excess solution is discharged into the sewage through the nozzle 24.

As a result of the use of the proposed invention, a significant economic effect is achieved by saving table salt, which is a valuable raw material for the chemical industry; the volume of harmful effluents and the content of salts in them are reduced, the consumption of fresh water for own water treatment needs is reduced,

Significant amounts of flue gases are cleaned of harmful impurities. The clarifier from the clarifier can be used as a raw material in the production of building materials.

Claims (1)

Claims installation of flue gas neutralization of alkaline regeneration wastewater of ion-exchange filters during water treatment, comprising an apparatus for neutralizing H-cation and anionite filters wastewater, an alkaline waste collection tank connected to an apparatus for neutralizing through a pipeline with a metering pump, a tank for receiving neutralized drains, equipped with a pH meter, flue gas supply pipeline with a fan and a flow regulator, the actuator of which is connected with the output of the pH meter signal a, characterized in that, in order to reduce the amount of effluent discharged into the environment and the possibility of using neutralized effluent to regenerate the Na-cation filter during water treatment, the installation is additionally equipped with an acid waste collection tank, a soda-solution preparation tank and a clarifier discharged wastewater, the input of the clarifier associated with the outputs of the collection tanks for acidic and alkaline wastewater and the tank for preparing soda solution, the inlet of which is connected through the metering pump to the collection tank of alkaline stations Cove and flue gas feed conduit, a solution yield of the clarifier coupled to the input of this solution in the apparatus for neutralization.