RU2233241C1 - Method of thermal deaeration of water - Google Patents

Abstract

FIELD: heat power engineering.

SUBSTANCE: invention can be used in thermal power stations and boiler plants. According to proposed method of thermal deaeration of water, heated source water and heating agent are supplied to deaerator, and deaerated water and flash steam are let out of deaerator. Flow rate of heating agent is regulated by preset residual content of oxygen in deaerated water. Simultaneously, flow rate of heating agent is regulated by residual content of carbon dioxide in deaerated water, value of flow rate of heating agent being set to provide preset content of most difficult to evacuate gas. Invention makes it possible to improve quality and economy at thermal deaeration owing to control of flow rate of heating agent by preset value of residual content of gas to be evacuated (namely oxygen O₂ or carbon dioxide CO₂) for which greater amount of heating agent delivered into deaerator is required.

EFFECT: improved of deaeration of water.

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Description

The invention relates to the field of power engineering and can be used in thermal power plants and boiler plants.

Known analogues are methods of thermal deaeration of water, in which the desorption of oxygen dissolved in water is carried out by contact of the treated water — chemically purified water and a heating agent — superheated water, and the deaerated water is removed from the deaerator. The flow rate of the heating agent supplied to the deaerator is controlled by the value of the specified residual dissolved oxygen content of O ₂ in deaerated make-up water of 50 μg / dm ³ using the regulator, control valve and sensor (see Patent No. 2144508 RU, IPC ⁶ C 02 F 1 / 20. The method of thermal deaeration of water / V. I. Sharapov, D. V. Zyura // Bulletin of inventions, 2000, No. 2). This analogue is adopted as a prototype.

The disadvantage of analogues and prototype is the reduced efficiency of the method of thermal deaeration of water due to increased energy costs for the supply of a heating agent, as well as the low quality of thermal deaeration of water when controlling only for a given residual oxygen content in water. In a number of modes of deaeration of hydrogen-cationic water, for example, despite providing a specified residual oxygen content of O _{2, the} normative quality of deaeration is not achieved, since the normative quality of carbon dioxide CO ₂ removal is not ensured, since a greater amount of heating agent is required for its removal. On the other hand, regulating the flow rate of the heating agent only by the residual CO ₂ content may also not ensure the normative quality of thermal deaeration, since, for example, deaeration of water treated with sodium cation methods requires a higher consumption of heating agent to achieve the normative residual oxygen content than for carbon dioxide removal. At the same time, in a number of modes, the consumption of the heating agent may be unnecessary to ensure the normative quality of deaeration. Thus, the existing disadvantages of the known method of thermal deaeration of water lead to a decrease in the quality and efficiency of thermal deaeration.

The technical result achieved by the present invention is to improve the quality and economy of thermal deaeration by achieving a given content of the most difficult to remove gas (oxygen O ₂ or carbon dioxide CO ₂ ) by changing the flow rate of the heating agent.

To achieve this result, a method for thermal deaeration of water is proposed, according to which source water and a heating agent are supplied to the deaerator, deaerated water and steam are removed from the deaerator, the flow rate of the heating agent is controlled by a predetermined residual oxygen content in deaerated water.

The difference of the proposed method is that the flow rate of the heating agent is simultaneously controlled by a predetermined residual content of carbon dioxide in deaerated water, and the flow rate of the heating agent is set based on the need to achieve a given content of the most difficult to remove gas.

A new method of thermal deaeration of water can improve the quality and efficiency of thermal deaeration of water by achieving a given content of the most difficult to remove gas (oxygen O ₂ or carbon dioxide CO ₂ ) by changing the flow rate of the heating agent.

Next, we consider the information confirming the possibility of carrying out the invention with obtaining the desired technical result.

The drawing shows a schematic diagram of an installation for thermal deaeration of water, explaining the method.

The installation contains a vacuum deaerator 1 with pipelines of the source water 2, heating agent 3 and deaerated water 4. The installation is equipped with a flow controller of the heating agent 5, which is connected on one side to the sensors of dissolved oxygen 6 and residual carbon dioxide 7 in deaerated make-up water, and with the other with the actuator 8 of the regulatory body 9 on the pipeline heating agent. As a regulator of the flow of the heating agent 5 can be used commercially available microprocessor controller Remicont R-130 - a programmable device or its earlier or later modifications.

Consider an example of the implementation of the claimed method of thermal deaeration of water.

The feed water of the heating network is deaerated in a vacuum deaerator 1 before being fed to the return line, for which source water and a heating agent are supplied to the deaerator. The flow rate of the heating agent is set based on the need to achieve a given content of the most difficult to remove gas (oxygen O ₂ or carbon dioxide CO ₂ ). During chemical treatment of water by the method of hydrogen cation, the source water is enriched with hydrogen ions H ⁺ (acidic medium), therefore, using the regulator 5, sensors 6 and 7 and the actuator 8 with the regulating body 9, the regulating parameter - the flow rate of the heating agent is set necessary to achieve predetermined residual carbon dioxide content in deaerated water (pH 8.33). When liming water, the source water is enriched with OH ^- ions (alkaline medium) and in this case, using the regulator 5, sensors 6 and 7 and the actuator 8 with the regulating body 9, the regulating parameter - the flow rate of the heating agent is set necessary to achieve the desired residual content of the most gas that is difficult to remove in this mode — dissolved oxygen in deaerated water (50 μg / dm ³ ).

At a number of thermal power plants, water treatment plants contain structures at different times in the queue of hydrogen-cationization, sodium-cationization, and liming. Depending on the total water flow rate, the proportion of water supplied to the thermal deaeration from different stages can vary significantly, which means that in accordance with the proposed method the flow rate of the heating agent in front of the deaerators will also change. Note that the consumption of the heating agent according to the proposed method is kept to the minimum necessary to remove the most difficult to remove gas, which ensures both the quality and the cost-effectiveness of thermal deaeration.

Thus, the new method improves the quality and efficiency of thermal deaeration of water by achieving a predetermined content of the most difficult to remove gas (oxygen O ₂ or carbon dioxide CO ₂ ) by changing the flow rate of the heating agent supplied to the deaerator.

Claims (1)

The method of thermal deaeration of water, in which heated source water and a heating agent are supplied to the deaerator, deaerated water and steam are removed from the deaerator, the flow rate of the heating agent is controlled by a predetermined residual oxygen content in the deaerated water, characterized in that the flow rate of the heating agent is simultaneously controlled by a predetermined residual the content of carbon dioxide in deaerated water, and the flow rate of the heating agent is set based on the need to achieve a given content of the most difficult yaemogo gas.