RU2801359C1 - Method of water treatment at a thermal power plant - Google Patents

Abstract

FIELD: thermal; industrial energy.

SUBSTANCE: invention can be used for chemical water treatment for consumers. The method includes the process of preliminary water purification, water filtration by reverse osmosis, removal of dissolved gases, collection of purified water for subsequent supply to the consumer. The pre-treatment process includes coagulation and mechanical filtration of water, water heating up to 30-45°C, and then filtration sequentially in three stages: ultrafiltration, nanofiltration and reverse osmosis filtration.

EFFECT: simplification of water treatment technology by reducing the stages of water treatment by eliminating the ion exchange process for deep water desalination while increasing the productivity of water purification by eliminating additional utilization of chemical reagents and improving filtration, additional water heating and additional ultra- and nanofiltration for water purification.

1 cl, 3 ex, 1 dwg

Description

The present invention relates to the field of thermal and industrial energy and can be used for chemical water treatment for consumers.

Known system of chemical water treatment /Patent No. 2551499, IPC C02F 9/04 C02F 1/42 C02F 1/44 C02F 1/52 B01D 61/00 publ. 05/27/2015 Chichirov A.A., Chichirova N.D., Girfanov A.A., Filimonov A.G., Saitov S.R./

The essence of the method lies in the fact that water is purified in a water treatment plant of a thermal power plant, first the water is pre-purified, then it is fed to a clarifier, where the process of coagulation and softening of water is carried out by dosing reagents of FeCl ₃ solution and NaOH solution, after which the water is clarified in a mechanical filter , then the water is filtered by reverse osmosis, after using ion exchange, for deep desalination of water, which contains an H-ionization filter and an OH-ionization filter connected in series, chemically purified water is obtained to feed the heating system, then the water is fed into the deaerator, in which removal dissolved gases connected to a high pressure steam boiler. The proposed method will partially reduce the consumption of the amount of reagents for the regeneration of ion-exchange filters, simplify the technological scheme and increase the purity by reducing the salt content of chemically purified water to 610 g/t, and reduce the amount of waste regeneration solutions discharged.

The disadvantages of the described method include:

- multi-stage technological scheme;

- the need to dispose of a large amount of spent chemicals used to regenerate ion exchange filters for deep water desalination;

The technical objective of this invention is to eliminate these shortcomings, namely, the simplification of water treatment technology by reducing the stages of water treatment by eliminating the ion exchange process for deep water desalination, while increasing the productivity of water purification by eliminating additional utilization of chemical reagents and improving filtration, additional heating of water and additional ultra - and nanofiltration for water purification.

The task is achieved by the fact that in the method, including the process of pre-treatment of water, coagulation, water filtration by reverse osmosis, removal of dissolved gases, then the collection of purified water for subsequent supply to the consumer, characterized in that in the process of pre-treatment the water is additionally heated to 30-45 °C, and filtration is carried out sequentially in three stages, ultrafiltration, nanofiltration and reverse osmosis filtration.

The essential difference of the proposed method is the inseparable set of actions set forth in the formula, which allows to reduce the viscosity and density of water, as well as increase the mobility of impurities and improve the quality of water purification, due to additional heating of water, in the process of preliminary water purification and additional filtration of water in succession in three stages, ultrafiltration, nanofiltration and reverse osmosis filtration, which reduces the consumption of reagents for the regeneration of ion exchange filters for deep water desalination, simplify the process flow by eliminating waste chemical solutions from the regeneration process.

The essence of the invention of water purification is implemented on the following equipment of Fig. 1.

The figure has the following symbols:

1 - heat exchanger

2 - clarifier

3 - mechanical filter

4 - coagulated water tank

5 - heat exchanger

6 - ultrafiltration filter

7 - nano filtration filter

8 - reverse osmosis filter

9 - deaerator

10 - boiler

11 - source water pipe

12 - coagulant tank

13 - coagulant tank

14 - sludge discharge pipe

15 - mechanical filter wash water pipe

16 - waste water pipe

17 - waste water pipe

18 - waste water pipe

19 - waste water pipe

The water treatment plant of the thermal power plant contains elements of water purification, preliminary water purification, membrane water purification tanks with a heat exchanger and a deaerator connected in series.

Example 1

The method of water purification was implemented in the water treatment plant, which operates as follows.

The source water 11 is supplied for preliminary purification, to the heat exchanger 1, where the water is heated to a temperature of 30°C, then the coagulation process is carried out in the clarifier 2 by supplying reagents from tank 12 and tank 13, for example, Al ₂ SO ₄ , Ca( OH) ₂ and subsequent clarification in a mechanical filter 3, behind which a coagulated water tank 4 is installed. The clarified water after the mechanical filter 3 is additionally filtered in three stages by ultrafiltration, nanofiltration and reverse osmosis filtration 6, 7, 8. The water first passes through the heat exchanger 5 for heating up to 30-35 ° C, to reduce the viscosity and density of water, and as a result, increase the mobility and quality of water purification, after that, pumps under a pressure of at least 6 bar pump water sequentially to ultra-6 filters, nanofiltration 7 to remove particles of a larger size, then the water is pumped under a pressure of 10 bar to the reverse osmosis filter 8, to further purify the water from particles with sizes of 0.001-0.0001 microns, then the water is fed into the deaerator 9, in which unwanted dissolved gas impurities are removed and then purified water is supplied with a salt content of 300 g/t in high-pressure boilers 10 to the consumer.

Technical result achieved: this technological process makes it possible to simplify the process of water purification by eliminating ion exchange for deep water desalination and to increase the productivity of water purification by improving filtration in three stages, reverse osmosis filtration at a pressure of at least 10 bar and by heating water in a heat exchanger up to 30-35°C, as a result, purified water with a salt content of 300 g/t is obtained.

Example 2

The method of water purification was implemented in the water treatment plant, which operates as follows.

Source water 11 is supplied for preliminary purification, to the heat exchanger 1, where the water is heated to a temperature of 35°C, then the coagulation process is carried out in the clarifier 2 by supplying reagents from tank 12 and tank 13, for example, Al ₂ SO ₄ , Ca(OH ) ₂ and subsequent clarification in a mechanical filter 3, behind which a coagulated water tank 4 is installed. The clarified water after the mechanical filter 3 is additionally filtered in three stages by ultrafiltration, nanofiltration and reverse osmosis filtration 6, 7, 8. The water first passes through the heat exchanger 5 for heating to 35-40 ° C, to reduce the viscosity and density of water, and as a result, increase the mobility and quality of water purification, after that, pumps under a pressure of at least 6 bar pump the water sequentially to ultra - 6 filters, nanofiltration 7 to remove particles of a larger size, then the water is pumped under a pressure of at least 15 bar to the reverse osmosis filter 8, to further purify the water from particles with sizes of 0.001-0.0001 microns, then the water is fed into the deaerator 9, in which unwanted dissolved gas impurities are removed and then the purified water is supplied with a salt content of 200 g/t to the high pressure boilers 10 to the consumer.

Technical result achieved: this technological process makes it possible to simplify the process of water purification by eliminating ion exchange for deep water desalination and to increase the productivity of water purification by improving filtration in three stages, reverse osmosis filtration under a pressure of at least 15 bar and by heating water in a heat exchanger up to 35-40°C, as a result, purified water with a salt content of 200 g/t is obtained.

Example 3

The method of water purification was implemented in the water treatment plant, which operates as follows.

Source water 11 is supplied for preliminary treatment, to the heat exchanger 1, where the water is heated to a temperature of 40°C, then the coagulation process is carried out in the clarifier 2 by supplying reagents from tank 12 and tank 13, for example, Al ₂ SO ₄ , Ca(OH) ₂ and subsequent clarification in a mechanical filter 3, behind which a coagulated water tank 4 is installed. The clarified water after the mechanical filter 3 is additionally filtered in three stages by ultrafiltration, nanofiltration and reverse osmosis filtration 6, 7, 8. The water first passes through the heat exchanger 5 for implementation heating to 40-45°C, to reduce the viscosity and density of water, and as a result, increase the mobility and quality of water purification, after that, pumps under a pressure of at least 6 bar pump the water sequentially to ultra - 6 filters, nanofiltration 7 to remove more particles large size, then the water is pumped under a pressure of at least 20 bar to the reverse osmosis filter 8, to further purify the water from particles with sizes of 0.001-0.0001 microns, then the water is fed into the deaerator 9, in which unwanted dissolved gas impurities are cleaned and then purified water is supplied with a salt content of 100 g/t in high pressure boilers 10 to the consumer.

Technical result achieved: this technological process makes it possible to simplify the process of water purification by eliminating ion exchange for deep water desalination and to increase the productivity of water purification by improving filtration in three stages, reverse osmosis filtration under a pressure of at least 20 bar and by heating water in a heat exchanger up to 40-45°C, resulting in purified water with a salt content of 100 g/t.

The implementation of the proposed solution allows:

- Simplify the technological scheme and the process of water treatment, reduce the consumption of reagents for filter regeneration, by eliminating the ion exchange process for deep water desalination;

- improve environmental performance in the implementation of the water treatment process by eliminating the process of recycling waste chemicals.

Claims (1)

The method of water treatment at a thermal power plant, including the process of pre-treatment of water, including coagulation and mechanical filtration of water, filtration of water by reverse osmosis, removal of dissolved gases, then collection of purified water for subsequent supply to the consumer, characterized in that during the pre-treatment process the water is additionally heated up to 30 -45°C, and then filtration is carried out sequentially in three stages: ultrafiltration, nanofiltration and reverse osmosis filtration.

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