RU2244208C1 - Method for thermal deaeration of water - Google Patents

Abstract

FIELD: heat power engineering, applicable at thermal power stations and boiler plants.

SUBSTANCE: heated starting water and heating agent are fed to the deaerator, deaerated water and flash steam are discharged from the deaerator, and the residual content of oxygen in the deaerated water is measured, an impulse from the deaerated water is measured, an impulse from the oxygen content transducer is transmitted to the flash steam consumption regulator, from which in turn, a control signal is transmitted to the actuating mechanism of the regulating member of consumption of flash steam. At the same time an impulse from the transducer of the residual content of carbon dioxide in the deaerated water is applied to the flash steam consumption regulator, and the flash steam consumption control is effected according to the preset value of the residual content of exhausted gas, for attaining of which a larger quantity of the flash steam is required.

EFFECT: enhanced quality and economical efficiency of thermal deaeration due the flash steam consumption control according to the preset value of the residual content of the discharged gas (oxygen O₂ or carbon dioxide CO₂).

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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 desorption of oxygen dissolved in water is carried out by contact of the treated water — chemically purified water and a heating agent — superheated water, deaerated water and vapor are removed from the deaerator, the residual oxygen content in the deaerated water is measured, and the pulse from the sensor the oxygen content is transferred to the evaporator flow regulator, from which, in turn, a control signal is transmitted to the actuator of the regulator of the evaporator flow (see Paten №2142418 (RU) IPC ⁶ C 02 F 1/20. A process of thermal deaeration of water / V.I.Sharapov, D.V.Tsyura // Bulletin of Inventions 1999, №34). 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 the increased energy costs for removal of the vapor, as well as the low quality of thermal deaeration of water when controlling only for a given residual oxygen content in the water. In a number of modes of deaeration of hydrogen-cationized water, for example, despite the provision of a predetermined 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 its removal requires a higher evaporation rate. On the other hand, regulating the flow rate of the vapor 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 cationic methods requires a higher vapor flow rate to achieve the standard residual oxygen content than to remove carbon dioxide. At the same time, in a number of modes, the flow rate of the vapor may be excessive 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 efficiency of thermal deaeration by controlling the flow rate of the vapor according to a given value of the residual content of the removed gas (oxygen O ₂ or carbon dioxide CO ₂ ), which requires a higher flow rate of the vapor discharged from the deaerator.

To achieve this result, a method is proposed for thermal deaeration of water, by which feed water and a heating agent are supplied to the deaerator, deaerated water and vapor are removed from the deaerator, the residual oxygen content in the deaerated water is measured, a pulse from the oxygen content sensor is transmitted to the evaporator flow regulator, from which in turn, transmit the control signal to the regulator of the flow rate of the vapor.

The difference of the proposed method is that the vapor flow regulator is simultaneously supplied with a pulse from a sensor of residual carbon dioxide content in deaerated water, and the vapor flow rate is controlled by a predetermined residual gas content, to achieve which a larger amount of vapor is required.

A new method of thermal deaeration of water can improve the quality and efficiency of thermal deaeration of water by controlling the flow rate of the vapor according to a given value of the residual content of the removed gas (oxygen O ₂ or carbon dioxide CO ₂ ), which requires a larger amount of vapor discharged from the deaerator.

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, the heating agent 3, the deaerated water 4 and the outlet of the vapor 5. The installation is equipped with a flow regulator 6, which is connected on one side to the sensors of dissolved oxygen 7 and residual carbon dioxide 8 in the deaerated feed water, and on the other with the actuator 9 of the regulatory body 10 on the discharge pipe 5. As a regulator of the flow of vapor 6 can be used commercially available microprocessor control lehr Remicont R-130 - programmable device or its earlier or later modifications.

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

The make-up water of the heating system is deaerated in a vacuum deaerator 1, for which source water and a heating agent are supplied to the deaerator. Deaerated water and vapor are removed from the deaerator. The vapor flow rate 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 ). In the chemical treatment of water by the hydrogen cation method, the source water is enriched with 1H ⁺ hydrogen ions (acidic medium), therefore, using the regulator 6, sensors 7 and 8 and the actuator 9 with regulator 10, the regulating parameter — the vapor flow rate — is set to achieve the desired residual carbon dioxide in deaerated water (pH 8.33). When liming the water, the source water is enriched with OH ^- ions (alkaline medium), and in this case, using the regulator 6, sensors 7 and 8 and the actuator 9 with the regulating body 10, the regulating parameter - the vapor flow rate is necessary to achieve the specified residual content of 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 vapor discharged from the deaerator will also change. Note that the vapor flow rate according to the proposed method is supported by 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 by controlling the vapor flow rate for a given value of the residual content of the removed gas (oxygen O ₂ or carbon dioxide CO ₂ ), which requires a higher flow rate of the vapor discharged from the deaerator.

Claims (1)

The method of thermal deaeration of water, by which source water and a heating agent are supplied to the deaerator, deaerated water and vapor are removed from the deaerator, the residual oxygen content in the deaerated water is measured, a pulse from the oxygen content sensor is transmitted to the evaporator flow regulator, from which, in turn, transmit a control signal to the actuator of the regulating body of the flow rate of the vapor, characterized in that the pulse flow rate is simultaneously transmitted from the sensor of the residual content of carbon dioxide to the regulator of the flow rate of the vapor and in deaerated water, and vapor flow control is performed for a given value of residual exhaust gas in order to achieve a greater amount of vapor necessary.