CN220249971U - System for reducing dissolved oxygen in boiler feed water - Google Patents

Abstract

The application provides a system for reducing boiler feed water dissolved oxygen, which comprises a deaerator, a cooling unit, a heat exchange unit and a return water tank. Deaerators are used to reduce the oxygen content of boiler feedwater. The cooling unit comprises a cooler and a cooling water pipeline, wherein the cooling water pipeline is provided with a water inlet end and a water outlet end, and the water inlet end is connected with the cooler. The heat exchange unit is used for condensing exhaust steam of the steam turbine into water, and is connected with the water outlet end of the cooling water pipeline. The return water tank is connected with the water outlet end of the cooling water pipeline; the return water tank is connected with the deaerator through a return water pump. Compared with the prior art, the technical scheme is characterized in that the boiler water supply is deoxidized mainly through the deoxidizer, and the cooling water of the cooling unit is heated by being matched with the return water tank, so that the temperature of the cooling water is increased, the secondary deoxidizing effect is achieved, and the deoxidizing efficiency is further improved.

Description

System for reducing dissolved oxygen in boiler feed water

Technical Field

The application relates to the field of boiler feed water, in particular to a system for reducing dissolved oxygen in boiler feed water.

Background

The dissolved oxygen of the boiler feed water of the thermal generator set is directly related to factors such as corrosion and scaling of oxygen in the steam-water heating surface of the boiler and the pipeline. The oxygen content of boiler feed water is too high, which can cause the problems of overheat heating surface, bulge creep, rupture and tube explosion, and the like, thereby causing great potential safety hazard to the unit. The water supply quality control indexes are as follows: the hydrogen conductivity is less than or equal to 0.3us/cm, the dissolved oxygen is less than or equal to 7 mug/l, the PH is maintained between 9.2 and 9.6, the silicon dioxide is less than or equal to 15 mug/l, and the hydrazine is less than or equal to 30 mug/l; condensed water control index: dissolved oxygen is less than or equal to 50 mug/l, and hydrogen conductivity is less than or equal to 0.3us/cm.

More information about the above solutions can also be found in the following documents: the patent document with the application number of 201420619387.4 provides a water supply deoxidization system of a coke dry quenching boiler, which comprises a coke dry quenching boiler, a steam source, a pressure deoxidizer, a boiler economizer, a deoxidization water tank and a water supply pump, wherein the deoxidization water tank is connected with the pressure deoxidizer and the boiler economizer through pipe fitting valves; the deoxidizing water tank is connected with a valve of a pipe fitting of the coke dry quenching boiler through a water feeding pump. Through the system, the oxygen content of the water discharged from the deaerator is reduced, the water supply temperature of the boiler is increased, the wall surface temperature of the boiler economizer is increased, the low-temperature corrosion of the wall surface is further prevented, and the steam yield of the boiler is increased.

In the process of implementing the present utility model, the inventor finds that the following problems exist in the prior art: the existing boiler cooling water has high oxygen content, unqualified water supply index, and the cooling water is mixed into the condenser to easily cause oxygen corrosion on the heating surface of the steam-water pipeline, thereby influencing the safety and economic operation of the unit.

Disclosure of Invention

In view of the above problems, there is a need to provide a technical solution for reducing the dissolved oxygen in the boiler feed water, so as to solve the problem of the prior art that the oxygen content of the boiler cooling water is high.

To achieve the above object, the present application provides a system for reducing dissolved oxygen in boiler feedwater, comprising:

the deaerator is used for reducing the oxygen content in the boiler feed water;

the cooling unit comprises a cooler and a cooling water pipeline, the cooling water pipeline is provided with a water inlet end and a water outlet end, and the water inlet end is connected with the cooler;

the heat exchange unit is used for condensing the exhaust steam of the steam turbine into water and is connected with the water outlet end of the cooling water pipeline;

the return water tank is connected with the water outlet end of the cooling water pipeline; the return water tank is connected with the deaerator through a return water pump.

In some embodiments, a hydrophobic tank is further included, the hydrophobic tank for storing hydrophobic water; the drain tank is provided with a drain pump for connecting the drain tank and the deaerator.

In some embodiments, the rated flow of the drain pump is 120m ³ And/h, 110KW power and 153m lift.

In some embodiments, an automatic water replenishment device is also included for controlling the replenishment of the drain pump.

In some embodiments, the automatic water replenishing device comprises a control unit, a pressure sensor and a liquid level sensor, wherein the pressure sensor is arranged in the deaerator, the liquid level sensor is arranged in the drain tank, and the control unit is electrically connected with the pressure sensor and the liquid level sensor.

In some embodiments, the cooler comprises a cat-foot cooler and an EH cooler, and the water inlet is connected to the cat-foot cooler and the EH cooler, respectively.

In some embodiments, the cooling unit further comprises a water sealed cylinder disposed at the water outlet end of the cooling water pipeline.

In some embodiments, the number of the water seal cylinders is more than two, and at least one water seal cylinder is connected with the return water tank.

Compared with the prior art, the technical scheme is characterized in that the boiler water is deoxidized mainly through the deoxidizer, and the cooling water of the cooling unit is heated by matching with the return water tank, so that the temperature of the cooling water is increased, the secondary deoxidizing effect is achieved, and the deoxidizing efficiency is further improved; the return water with lower temperature of the cat claw cooler and the EH cooler of the steam turbine is changed into a route and led to the return water tank, so that the temperature of cooling water is further improved, the oxygen content of the cooling water is removed, the return water pump pumps the oxygen content of the cooling water back to the oxygen remover, the oxygen content of the condensed water is reduced, the qualified range of the water supply dissolved oxygen of the boiler can be ensured, and the safe and economic operation of the unit is ensured.

The foregoing summary is merely an overview of the present application, and is provided to enable one of ordinary skill in the art to make more clear the present application and to be practiced according to the teachings of the present application and to make more readily understood the above-described and other objects, features and advantages of the present application, as well as by reference to the following detailed description and accompanying drawings.

Drawings

The drawings are only for purposes of illustrating the principles, implementations, applications, features, and effects of the present application and are not to be construed as limiting the application.

In the drawings of the specification:

FIG. 1 is a schematic diagram of a system for reducing dissolved oxygen in boiler feedwater according to an embodiment of the present application;

FIG. 2 is a schematic structural view of a deaerator according to an embodiment of the present disclosure;

FIG. 3 is a schematic view of a hydrophobic tank according to an embodiment of the present application;

FIG. 4 is a schematic view of a cooling unit according to an embodiment of the present disclosure;

FIG. 5 is a partial schematic view of a system for reducing dissolved oxygen in boiler feedwater according to an embodiment of the present application.

Reference numerals referred to in the above drawings are explained as follows:

1. a deaerator;

2. the device comprises a cooling unit 21, a cooling water pipeline 22, a cat claw cooler 23, an EH cooler 24 and a water seal cylinder;

3. a heat exchange unit;

4. a return water tank 41, a return water pump;

5. a hydrophobic tank, 51, a hydrophobic pump;

6. a coagulation pump;

7. a low pressure heater;

8. a steam turbine.

Detailed Description

In order to describe the possible application scenarios, technical principles, practical embodiments, and the like of the present application in detail, the following description is made with reference to the specific embodiments and the accompanying drawings. The embodiments described herein are only used to more clearly illustrate the technical solutions of the present application, and are therefore only used as examples and are not intended to limit the scope of protection of the present application.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the present application. The appearances of the phrase "in various places in the specification are not necessarily all referring to the same embodiment, nor are they particularly limited to independence or relevance from other embodiments. In principle, in the present application, as long as there is no technical contradiction or conflict, the technical features mentioned in the embodiments may be combined in any manner to form a corresponding implementable technical solution.

Unless defined otherwise, technical terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application pertains; the use of related terms herein is for the description of specific embodiments only and is not intended to limit the present application.

In the description of the present application, the term "and/or" is a representation for describing a logical relationship between objects, which means that there may be three relationships, e.g., a and/or B, representing: there are three cases, a, B, and both a and B. In addition, the character "/" herein generally indicates that the front-to-back associated object is an "or" logical relationship.

In this application, terms such as "first" and "second" are used merely to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual number, order, or sequence of such entities or operations.

Without further limitation, the use of the terms "comprising," "including," "having," or other like terms in this application is intended to cover a non-exclusive inclusion, such that a process, method, or article of manufacture that comprises a list of elements does not include additional elements but may include other elements not expressly listed or inherent to such process, method, or article of manufacture.

As in the understanding of the "examination guideline," the expressions "greater than", "less than", "exceeding", and the like are understood to exclude the present number in this application; the expressions "above", "below", "within" and the like are understood to include this number. Furthermore, in the description of the embodiments of the present application, the meaning of "a plurality of" is two or more (including two), and similarly, the expression "a plurality of" is also to be understood as such, for example, "a plurality of groups", "a plurality of" and the like, unless specifically defined otherwise.

In the description of the embodiments of the present application, spatially relative terms such as "center," "longitudinal," "transverse," "length," "width," "thickness," "up," "down," "front," "back," "left," "right," "vertical," "horizontal," "vertical," "top," "bottom," "inner," "outer," "clockwise," "counter-clockwise," "axial," "radial," "circumferential," etc., are used herein as terms of orientation or positional relationship based on the specific embodiments or figures, and are merely for convenience of description of the specific embodiments of the present application or ease of understanding of the reader, and do not indicate or imply that the devices or components referred to must have a particular position, a particular orientation, or be configured or operated in a particular orientation, and therefore are not to be construed as limiting of the embodiments of the present application.

Unless specifically stated or limited otherwise, in the description of the embodiments of the present application, the terms "mounted," "connected," "affixed," "disposed," and the like are to be construed broadly. For example, the "connection" may be a fixed connection, a detachable connection, or an integral arrangement; the device can be mechanically connected, electrically connected and communicated; it can be directly connected or indirectly connected through an intermediate medium; which may be a communication between two elements or an interaction between two elements. The specific meanings of the above terms in the embodiments of the present application can be understood by those skilled in the art to which the present application pertains according to the specific circumstances.

The steam turbine is also called a steam turbine engine, and is a rotary steam power device, high-temperature and high-pressure steam passes through a fixed nozzle to become accelerated airflow and then is sprayed onto blades, so that a rotor provided with a blade row rotates and simultaneously does work outwards. Steam turbines are the main equipment of modern thermal power plants and are also used in metallurgical industry, chemical industry and ship power plants.

The steam turbine usually works under the conditions of high temperature, high pressure and high rotating speed, is a relatively precise heavy machine, and generally needs to be matched with complete equipment consisting of a boiler (or other steam generators), a generator (or other driven machines), a condenser, a heater, a pump and the like.

Referring to fig. 1, the present embodiment provides a system for reducing dissolved oxygen in boiler feed water, which includes a deaerator 1, a cooling unit 2, a heat exchange unit 3, and a return water tank 4. The deaerator 1 is used to reduce the oxygen content in the boiler feed water. The cooling unit 2 comprises a cooler and a cooling water pipeline 21, wherein the cooling water pipeline 21 is provided with a water inlet end and a water outlet end, and the water inlet end is connected with the cooler. The heat exchange unit 3 is used for condensing the exhaust steam of the steam turbine into water, and the heat exchange unit 3 is connected with the water outlet end of the cooling water pipeline 21. The return water tank 4 is connected with the water outlet end of the cooling water pipeline 21; the return water tank 4 is connected to the deaerator 1 by a return water pump 41.

As shown in fig. 2, the deaerator 1 is one of the key equipment of the boiler and the heating system, for example, the deaerator 1 has poor deaeration capability, and serious loss caused by corrosion of a boiler water supply pipeline, an economizer and other auxiliary equipment is caused, and the economic loss caused by the corrosion is tens or hundreds times of the manufacturing cost of the deaerator 1. The deaerator 1 is composed of a deaerator head and a water tank. The structure of the deaeration head consists of six parts, namely a shell, a membrane rotating device group, a water grate, a liquid-vapor net, a vapor distribution plate and a vapor-water separator. The water tank is composed of a main body, accessories and a water seal cylinder 24.

The cooling unit 2 comprises a cooler and a cooling water pipeline 21, wherein the cooling water pipeline 21 is provided with a water inlet end and a water outlet end, and the water inlet end is connected with the cooler. The cooler is internally provided with cooling water, the temperature of the cooling water is lower, the oxygen content is higher, and the cooling water enters the heat exchange unit 3 through a cooling water pipeline 21.

The heat exchange unit 3 is a component for condensing the turbine exhaust steam into water. In particular, the heat exchange unit 3 may be a condenser. The condenser is a heat exchanger for condensing steam discharged by a steam turbine into water, which is also called a water re-heater. The condenser is mainly used in a turbine power device and is divided into a water-cooling condenser and an air-cooling condenser.

The return water tank 4 mainly stores recycled cooling water, and the temperature of the return water tank 4 is higher. Whereas a typical cooler, such as cat-foot cooler 22, has a relatively low water temperature, the direct introduction of cooling water into deaerator 1 results in a rapid decrease in the temperature within deaerator 1, resulting in a rapid change in the temperature within deaerator 1. And after the cooling water enters the return water tank 4, the temperature of the cooling water is increased, the oxygen content in the water is reduced, and the effect equivalent to deoxidization is achieved. The cooling water is connected with the deaerator 1 through the return water pump 41, so that fluctuation of temperature and pressure in the deaerator 1 is avoided, and normal operation of the deaerator 1 is ensured.

Compared with the prior art, the technical scheme is characterized in that the deaerator 1 is mainly used for deaerating boiler feed water, and the return water tank 4 is matched for heating cooling water of the cooling unit 2, so that the temperature of the cooling water is increased, a secondary deaeration effect is achieved, and deaeration efficiency is further improved; the return water with lower temperature of the parts of the steam turbine cat claw cooler 22 and the EH cooler 23 is led to the return water tank 4 to further improve the temperature of cooling water, the oxygen content of the cooling water is removed, the return water pump 41 pumps back the oxygen content of the oxygen remover 1, the oxygen content of condensed water is reduced, the condition that the pressure of the oxygen remover 1 is severely fluctuated due to instantaneous heat absorption after the low-temperature water enters the oxygen remover 1 can be ensured, the change of the pressure and the temperature of the oxygen remover 1 is reduced, the influence on the working efficiency of the oxygen remover 1 is reduced, the oxygen content of the water supply of a boiler is further reduced, and the safe and economic operation of a unit is ensured.

As shown in fig. 3, in some other embodiments, a hydrophobic tank 5 is further included, the hydrophobic tank 5 being used to store the hydrophobic water. The drain tank 5 is provided with a drain pump 51 for connecting the drain tank 5 and the deaerator 1.

The water in the water-repellent tank 5 is soft water, is drained by steam pipelines, superheaters and the like, is discharged by a steam drum, and can be reused. The drain pump 51 is a pump for draining water from the primary heater into the water supply pipe of the outlet of the primary heater. The drain pump 51 pumps the water in the drain tank 5 back to the deaerator 1 for reuse, thereby reducing resource waste. The water in the hydrophobic tank 5 is pumped into the deaerator 1 through the hydrophobic pump 51 to deoxidize, so that the oxygen content in the water is reduced.

In some other embodiments, the rated flow of the drain pump 51 is 120m3/h, the power is 110KW, and the lift is 153m. The drain pump 51 with small flow, low lift and small power is selected, so that the power consumption is low, the running power consumption of the pump is saved, the temperature of the drain pump 51 with small flow is higher than that of the drain pump 51 with large flow, and the content of hydrophobic oxygen can be further reduced.

In some other embodiments, an automatic water replenishment device is also included for controlling the replenishment of the drain pump 51.

The automatic water supplementing device controls the water supplementing amount of the drain pump 51 according to the pressure and temperature change in the deaerator 1, thereby adjusting the pressure and temperature in the deaerator 1, and keeping the pressure and temperature in the deaerator 1 in a stable range.

In some other embodiments, the automatic water replenishing device comprises a control unit, a pressure sensor and a liquid level sensor, wherein the pressure sensor is arranged in the deaerator 1, the liquid level sensor is arranged in the drain tank 5, and the control unit is electrically connected with the pressure sensor and the liquid level sensor.

The pressure sensor detects the pressure fluctuation in the deaerator 1 and sends the detection result to the control unit in a signal mode, and the control unit is electrically connected with the drain pump 51 and the liquid level sensor. When the liquid level sensor detects that the liquid level in the drain tank 5 is higher than or lower than a preset liquid level, the drain pump 51 is controlled to start water replenishment or stop water replenishment.

In some other embodiments, the coolers include a cat-foot cooler 22 and an EH cooler 23, and the water inlet is connected to the cat-foot cooler 22 and the EH cooler 23, respectively.

The cooling water temperatures of the cat-foot cooler 22 and the EH cooler 23 are low, and the cat-foot cooler 22 and the EH cooler 23 are connected to the water inlet end of the cooling water pipe 21.

In some other embodiments, the cooling unit 2 further includes a water seal cylinder 24, and the water seal cylinder 24 is disposed at the water outlet end of the cooling water pipe 21.

The water seal cylinder 24 is disposed at the water outlet end of the cooling water pipeline 21, and the cooling water passes through the water seal cylinder 24 and then enters the next process. The water seal cylinder 24 is a multi-stage water seal, the water level difference between the inner cylinder and the outer cylinder is used for keeping sealing under a certain pressure, water is needed to be supplemented at the beginning, and water is needed to be supplemented if the phenomenon of steam generation is found at the operation. When the water tank of the deaerator 1 is full of water, water can overflow through the water seal cylinder 24. When the deaerator 1 exceeds the normal working pressure, the water seal cylinder 24 acts to remove the stored water pressure and then discharge the steam, thus preventing the deaerator 1 from being overpressurized.

In some other embodiments, the number of the water seal cylinders 24 is more than two, and at least one water seal cylinder 24 is connected to the return water tank 4.

As shown in fig. 4, the number of the water seal cylinders 24 is 5 or more. Part of cooling water enters the condenser through the water seal cylinder 24, and the other part of cooling water enters the cooling water tank through the water seal cylinder 24.

As shown in fig. 5, the system for reducing dissolved oxygen in boiler feed water provided by the present application further comprises a condensate pump 6, a low-pressure heater 7 and a steam turbine 8. The deaerator is connected with a low-pressure heater 7.

The following examples are also provided for the reader's reference to understand certain embodiments of the present application more intuitively.

The scheme selects the drainage pump with small flow, low lift and small power, has low power consumption and saves the running power consumption of the pump. When the drain pump supplements water, the automatic water supplementing device can automatically control the water supplementing quantity in a variable frequency mode according to the pressure, temperature and liquid level change of the deaerator, and the condition that the dissolved oxygen of the deaerator water is out of standard due to the fact that the temperature and the pressure of the deaerator fluctuate greatly is prevented. The return water with lower temperature of the cooling water of the cat claw cooler and the EH cooler of the original steam turbine is led to a production return water tank, further absorbs heat and heats up, removes oxygen content of the cooling water, and then is pumped back to the deaerator by a return water pump, so that oxygen content of the condensed water is reduced, the oxygen content of the boiler feed water can be ensured to be in a qualified range, the temperature of the deaerator can be controlled between 140 ℃ and 150 ℃, the pressure is 0.45 MPa to 0.5MPa, the oxygen removal effect is improved due to the reduction of water temperature change, the oxygen content of the condensed water is reduced, and safe and economical operation of a unit is ensured.

Finally, it should be noted that, although the foregoing embodiments have been described in the text and the accompanying drawings of the present application, the scope of the patent protection of the present application is not limited thereby. All technical schemes generated by replacing or modifying equivalent structures or equivalent flows based on the essential idea of the application and by utilizing the contents recorded in the text and the drawings of the application, and the technical schemes of the embodiments are directly or indirectly implemented in other related technical fields, and the like, are included in the patent protection scope of the application.

Claims (7)

1. A system for reducing dissolved oxygen in boiler feedwater comprising:

the deaerator is used for reducing the oxygen content in the boiler feed water;

the cooling unit comprises a cooler and a cooling water pipeline, the cooling water pipeline is provided with a water inlet end and a water outlet end, and the water inlet end is connected with the cooler;

the heat exchange unit is used for condensing the exhaust steam of the steam turbine into water and is connected with the water outlet end of the cooling water pipeline;

the return water tank is connected with the water outlet end of the cooling water pipeline; the return water tank is connected with the deaerator through a return water pump.

2. The system for reducing dissolved oxygen in boiler feedwater of claim 1, further comprising a hydrophobic tank for storing the hydrophobic water; the drain tank is provided with a drain pump for connecting the drain tank and the deaerator.

3. The system for reducing dissolved oxygen in boiler feedwater of claim 2, further comprising an automatic water replenishment device for controlling the replenishment of the drain pump.

4. The system for reducing dissolved oxygen in boiler feedwater of claim 3, wherein the automatic water replenishment device comprises a control unit, a pressure sensor and a liquid level sensor, wherein the pressure sensor is arranged in the deaerator, the liquid level sensor is arranged in the drain tank, and the control unit is electrically connected with the pressure sensor and the liquid level sensor.

5. The system for reducing dissolved oxygen in boiler feedwater of claim 1, wherein the chiller includes a cat-foot cooler and an EH cooler, the water inlet end being connected to the cat-foot cooler and the EH cooler, respectively.

6. The system for reducing dissolved oxygen in boiler feedwater of claim 1, wherein the cooling unit further includes a water seal cartridge disposed at a water outlet end of the cooling water line.

7. The system for reducing dissolved oxygen in boiler feedwater of claim 6, wherein said number of water seal cartridges is greater than two, at least one of said water seal cartridges being connected to said return water tank.