CN210153770U - Low-load feed water backflow system of power station boiler - Google Patents
Low-load feed water backflow system of power station boiler Download PDFInfo
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- CN210153770U CN210153770U CN201920808218.8U CN201920808218U CN210153770U CN 210153770 U CN210153770 U CN 210153770U CN 201920808218 U CN201920808218 U CN 201920808218U CN 210153770 U CN210153770 U CN 210153770U
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Abstract
The utility model provides a low-load feed water reflux system of a power station boiler, which comprises a feed water pump, a water pump and a water pump, wherein the feed water pump is used for increasing the feed water pressure so as to send the feed water of the boiler to the power station boiler; a high pressure heater in communication with the feed pump and the utility boiler for heating the pumped boiler feed water and feeding it to the utility boiler; the flue gas treatment device is communicated with the power station boiler and is used for carrying out desulfurization and denitrification treatment on the flue gas; at least still include: and the feed water return pipeline assembly is respectively communicated with the water outlet of the high-pressure heater and the water inlet of the feed pump, and adjusts the water flow entering the power station boiler according to the outlet water temperature of the high-pressure heater. The utility model provides a power plant boiler low-load feedwater return system can solve the power plant boiler of thermal power plant and condense at low-load operation ammonium bisulfate, causes the denitration catalyst to lose activity and effect, and the emergence of the problem that the fume emission exceeds standard.
Description
Technical Field
The embodiment of the utility model provides a thermal power field, in particular to power plant boiler low-load feedwater return system is related to.
Background
In recent years, in the three northeast regions of China, the capacity of the power market is rich, peak-adjustable power supplies such as a gas turbine and pumped storage are scarce, the contradiction between the peak adjustment of a power grid and the flexibility of a thermal power generating unit is prominent, the capacity of the power grid for absorbing new energy such as wind power, photoelectricity, hydropower and nuclear power is insufficient, and the phenomena of wind abandoning, light abandoning, water abandoning and nuclear abandoning are serious. In order to meet the peak regulation requirement of a power grid and the survival requirement of a power plant in intense competition, deep peak regulation especially in non-heating seasons is imperative all the year.
The international definition of thermal flexibility includes two aspects:
(1) flexibility of load adjustment: deep peak regulation (low-load operation of a boiler and a steam turbine), quick start and stop of a unit, ramp rate of the unit, thermoelectric decoupling of a cogeneration unit and quick reduction of on-line load of the unit.
(2) Flexibility of fuel: the variability of the fuel of the thermal power plant comprises various fossil fuels such as coal, oil and gas, the co-combustion of the fossil fuel and biomass fuel, and even various renewable energy fuels such as complete biomass and garbage. At present, the main large-scale thermal power generating units in Denmark realize the conversion from the traditional pulverized coal furnace to the mixed combustion of biomass and further to the complete renewable energy fuels such as biomass or garbage.
In various thermal power flexibility deep peak regulation schemes, low-load operation of a boiler is the most commonly adopted technical scheme of each power plant, but at present, the SCR denitration system is arranged in the power plant for controlling pollutant emission in China, and the SCR system cannot work normally in a low-load operation state of the boiler. The main reason is that in the SCR reactor commonly used in coal-fired power stations, the normal active reaction temperature of the catalyst is generally 320-400 ℃. When the unit is operated at medium and low load, the smoke temperature at the inlet of the SCR reactor is the coal economizerThe outlet flue temperature may be below this temperature, which may cause the SCR catalyst activity to not be maintained at an optimum level at all times, and the reactor operating efficiency to be low, while also resulting in increased ammonia slip. NH slip from SCR reactor3With SO in flue gas3And H2O reacts to generate NH at a proper temperature4HSO4And a small amount of (NH)4)2SO4。NH4HSO4Has strong cohesiveness, can be attached to the surface of the air preheater and adsorb fly ash particles, and can be accumulated for a long time to cause ash blockage. NH (NH)4HSO4The amount of production increases with increasing ammonia slip. When other conditions such as denitration efficiency are kept constant, the most effective method for reducing the ammonia slip rate is to improve the SCR reaction efficiency. And in actual operation, because the unit load reduces, cause SCR entry flue-gas temperature to reach catalyst active temperature interval, then denitrification facility will be forced to withdraw from the operation to lead to the fume emission not up to standard.
The prior art scheme has the scheme that the flue gas temperature under the low-load working condition is increased by increasing a coal economizer bypass or a flue gas recirculation system, but the improvement of a flue and a boiler coal economizer has the defects of difficult construction, high cost, long construction period, large investment and the like, and the safe operation after the boiler is improved is greatly threatened, so that two complicated improvement measures are not generally considered by a plurality of power plants.
Content of application
The embodiment of the utility model provides a can solve power plant boiler's when the low-load operation ammonium bisulfate condense, cause denitration catalyst to lose activity and effect, the power plant boiler low-load feedwater return-flow system of the emergence of the problem that the fume emission exceeds standard.
In order to solve the above technical problem, an embodiment of the present application provides a utility boiler low-load feedwater recirculation system, including
A feed water pump for raising feed water pressure to feed boiler feed water to the utility boiler;
a high pressure heater in communication with the feed pump and the utility boiler for heating the pumped boiler feed water and feeding it to the utility boiler;
the flue gas treatment device is communicated with the power station boiler and is used for carrying out desulfurization and denitrification treatment on the flue gas;
at least still include: and the feed water return pipeline assembly is respectively communicated with the water outlet of the high-pressure heater and the water inlet of the feed pump, and adjusts the water flow entering the power station boiler according to the outlet water temperature of the high-pressure heater.
Preferably, the feed water return line assembly includes:
the return pipeline is respectively communicated with the water inlet of the water feeding pump and the water outlet of the high-pressure heater;
and the return valve is arranged on the return pipeline and used for adjusting the water flow of the return pipeline.
Preferably, the high-pressure heater is provided with a plurality of high-pressure heaters;
the feed water return pipeline assembly is at least one and is in matched connection with one or more high-pressure heaters.
Preferably, a first temperature sensor for detecting the temperature of feed water entering the utility boiler is arranged on a pipeline between the high-pressure heater and the utility boiler, and the first temperature sensor is electrically connected with an electric control component in the return valve, so that the electric control component adjusts the opening of the return valve according to the temperature detected by the first temperature sensor.
Preferably, a second temperature sensor for detecting the temperature of the flue gas is arranged at a flue gas inlet of the flue gas treatment device, and the second temperature sensor is electrically connected with an electric control component in the return valve, so that the electric control component adjusts the opening of the return valve according to the temperature detected by the second temperature sensor.
Preferably, the low-load feed water reflux system of the utility boiler further comprises a low-pressure heater and a deaerator, and steam output by the utility boiler forms condensed water and then sequentially enters the feed water pump through the low-pressure heater and the deaerator.
Preferably, the utility boiler low load feedwater return system further comprises a de-boiler drum and an economizer located in the utility boiler.
Can learn based on the publication of above-mentioned embodiment, the beneficial effect of this application embodiment lies in through setting up the return line subassembly and control the discharge in getting into the power plant boiler, and then guarantee to get into the feedwater temperature in the power plant boiler, so reach the feedwater temperature that improves to get into boiler economizer, and then the flue gas temperature that gets into the flue gas treater when improving power plant boiler low-load operation, the catalyst is to the temperature requirement of flue gas when satisfying denitration treatment, thereby avoid ammonium bisulfate to condense, cause denitration catalyst to lose activity and effect, the emergence of the problem that the fume emission exceeds standard.
Drawings
Fig. 1 is a schematic structural diagram of a low-load feedwater recirculation system of a utility boiler in an embodiment of the present invention.
Fig. 2 is a schematic structural diagram of a low-load feedwater return system of a utility boiler according to another embodiment of the present invention.
Reference numerals:
1-utility boiler; 2-a first temperature sensor; 3-a steam turbine; 4-a generator; 5-a high pressure heater; 6-low pressure heater; 7-a feed pump; 8-a deaerator; 9-a coal economizer; 10-a flue gas processor; 11-a reflux valve; 12-a return line; 13-a condenser; 14-removing the boiler barrel.
Detailed Description
Specific embodiments of the present application will be described in detail below with reference to the accompanying drawings, but the present application is not limited thereto.
It will be understood that various modifications may be made to the embodiments disclosed herein. The following description is, therefore, not to be taken in a limiting sense, but is made merely as an exemplification of embodiments. Other modifications will occur to those skilled in the art within the scope and spirit of the disclosure.
The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate embodiments of the disclosure and, together with a general description of the disclosure given above, and the detailed description of the embodiments given below, serve to explain the principles of the disclosure.
These and other characteristics of the present application will become apparent from the following description of preferred forms of embodiment, given as non-limiting examples, with reference to the attached drawings.
It should also be understood that, although the present application has been described with reference to some specific examples, a person of skill in the art shall certainly be able to achieve many other equivalent forms of application, having the characteristics as set forth in the claims and hence all coming within the field of protection defined thereby.
The above and other aspects, features and advantages of the present disclosure will become more apparent in view of the following detailed description when taken in conjunction with the accompanying drawings.
Specific embodiments of the present disclosure are described hereinafter with reference to the accompanying drawings; however, it is to be understood that the disclosed embodiments are merely examples of the disclosure that may be embodied in various forms. Well-known and/or repeated functions and structures have not been described in detail so as not to obscure the present disclosure with unnecessary or unnecessary detail. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present disclosure in virtually any appropriately detailed structure.
The specification may use the phrases "in one embodiment," "in another embodiment," "in yet another embodiment," or "in other embodiments," which may each refer to one or more of the same or different embodiments in accordance with the disclosure.
Hereinafter, embodiments of the present application will be described in detail with reference to the accompanying drawings.
As shown in FIG. 1, an embodiment of the present invention provides a low-load feedwater recirculation system of a utility boiler, which at least comprises:
a feed water pump 7 for raising a feed water pressure to feed the boiler feed water to the utility boiler 1;
a high-pressure heater 5 which is communicated with the feed water pump 7 and the utility boiler 1 and is used for heating the pumped boiler feed water and sending the boiler feed water into the utility boiler 1;
the flue gas treatment device is communicated with the power station boiler 1 and is used for carrying out desulfurization and denitrification treatment on the flue gas;
at least still include: and the feed water return pipeline 12 assembly is respectively communicated with the water outlet of the high-pressure heater 5 and the water inlet of the feed pump 7 and adjusts the water flow entering the power station boiler 1 according to the outlet water temperature of the high-pressure heater 5.
In this embodiment through setting up 12 subassemblies of return line and control the discharge in getting into power boiler 1, and then guarantee to get into the feedwater temperature in power boiler 1, so reach the feedwater temperature that improves economizer 9 in getting into power boiler 1, and then the flue gas temperature that gets into flue gas treater 10 when improving power boiler low-load operation, the catalyst is to the temperature requirement of flue gas when satisfying the denitration treatment, thereby avoid ammonium bisulfate to condense, cause the denitration catalyst to lose activity and effect, the emergence of the flue gas emission problem that exceeds standard. Moreover, the wide-load operation of the power station boiler 1 can be conveniently and safely realized, and the flexible deep peak regulation capability of the thermal power generating unit is promoted.
Specifically, the utility boiler 1 of the present embodiment is provided with not only the economizer 9 but also a boiler barrel 14. And still include low pressure feed water heater 6 and oxygen-eliminating device 8 in the system, power boiler 1 output steam partly through steam turbine 3, generator 4 generate electricity, partly through low pressure feed water heater 6, oxygen-eliminating device 8 entering in proper order after condenser 13 forms the condensate water in getting into water-feeding pump 7. The flue gas processor 10 is for denitration treating flue gas by using Selective Catalytic Reduction (SCR), and the flue gas processor 10 may also be referred to as an SCR system.
The return pipeline 12 assembly is respectively communicated with the water outlet of the high-pressure heater 5 and the water inlet of the water feeding pump 7 to form a circulating water path. The return line 12 subassembly is through controlling opening and blocking of this circulation water route realize the control to the inflow of power boiler 1, and then reaches the effect of controlling the temperature of intaking of power boiler 1 and the subsequent temperature that produces the flue gas.
Further, in the present embodiment, the temperature of the feed water entering the utility boiler 1 is detected by providing a temperature measuring point, for example, the first temperature sensor 2, on the pipe between the high-pressure heater 5 and the utility boiler 1. The temperature measuring point can be arranged at a position close to the water outlet of the high-pressure heater 5, or a plurality of temperature measuring points can be arranged on the pipeline, so that the detection precision of the inlet water temperature can be better ensured.
Continuing with FIG. 1, the return line 12 assembly in this embodiment includes:
a return pipeline 12 which is respectively communicated with the water outlet of the high-pressure heater 5 and the water inlet of the water feeding pump 7;
and a return valve 11 disposed on the return line 12 for regulating the flow rate of water in the return line 12.
The setting of the return valve 11 can be adjusted manually or by means of a signal. For example, the backflow valve 11 is an electric valve, and the utility boiler low-load feedwater backflow system also has a controller, which is electrically connected to the first temperature sensor 2 and the backflow valve 11, respectively, so as to analyze the temperature data sent by the first temperature sensor 2 when receiving the temperature data, and then send a signal to the backflow valve 11 according to the analysis result, so as to control the opening and opening angle of the backflow valve 11, or control the valve to close. Alternatively, the backflow valve 11 may have a control portion, the first temperature sensor 2 is electrically connected to the control portion, and the control portion may control the opening and opening angle of the backflow valve 11 or control the valve to be closed according to the received temperature detection data. Of course, the opening speed of the return valve 11 and the like may also be controlled. Of course, the return valve 11 may be only a common mechanical valve, and a worker may obtain detection data according to the monitoring of the first temperature sensor 2 and manually adjust the return valve 11 according to the data.
Preferably, in order to more accurately ensure that the temperature of the flue gas generated in the utility boiler 1 reaches the standard before entering the flue gas treatment device, in this embodiment, a second temperature sensor for detecting the temperature of the flue gas is further arranged at the flue gas inlet of the flue gas treatment device, and the second temperature sensor is electrically connected with the electric control component in the return valve 11, so that the electric control component can further adjust the opening degree of the return valve 11 according to the temperature detected by the second temperature sensor. Of course, if the controller is provided in the recirculation system, the second temperature sensor can also be electrically connected to the controller, so that the controller can adjust the recirculation valve 11 according to the detected temperature.
Further, the number of the high-pressure heaters 5 is not unique for different application scenarios. For example, the number of the high-pressure heaters 5 in this embodiment is three (i.e., a group of high-pressure heaters 5 is formed), and the number of the components of the return line 12 is not unique, and may be, for example, one or more, and may be correspondingly communicated with the water outlet of any one of the high-pressure heaters 5, or may be respectively matched with a plurality of high-pressure heaters 5.
For example, as shown in fig. 2, three high-pressure heaters 5 are arranged in a line, and the number of the return lines 12 is three, wherein the return lines 12 in the three return line 12 are used to communicate with a portion communicating with the water inlet of the feed pump 7 so as to be commonly connected with the water inlet of the feed pump 7. The other ends of the three return pipelines 12 provided with the return valves 11 are respectively communicated with the water outlets of the three high-pressure heaters 5, so that a circulating water path which can be controlled to be on or off by the return valves 11 is formed between each return pipeline 12 and the corresponding high-pressure heater 5, that is, the water flow of the three circulating water paths is respectively controlled by the return valves 11 of the three return pipelines 12, so that the feed water temperature finally entering the power station boiler 1 is improved, the heat absorption capacity of the feed water of the boiler in the rear flue economizer 9 of the power station boiler 1 is reduced, the inlet flue gas temperature of the flue gas treatment device is indirectly controlled to be not lower than 310 degrees, the flue gas treatment effect under the low-load operation condition of the power station boiler is further ensured, and the ammonia escape rate is reduced.
The above embodiments are only exemplary embodiments of the present application, and are not intended to limit the present application, and the protection scope of the present application is defined by the claims. Various modifications and equivalents may be made by those skilled in the art within the spirit and scope of the present application and such modifications and equivalents should also be considered to be within the scope of the present application.
Claims (7)
1. A low-load feed water reflux system for a utility boiler comprises
A feed water pump for raising feed water pressure to feed boiler feed water to the utility boiler;
a high pressure heater in communication with the feed pump and the utility boiler for heating the pumped boiler feed water and feeding it to the utility boiler;
the flue gas treatment device is communicated with the power station boiler and is used for carrying out desulfurization and denitrification treatment on the flue gas;
it is characterized by at least comprising: and the feed water return pipeline assembly is respectively communicated with the water outlet of the high-pressure heater and the water inlet of the feed pump, and adjusts the water flow entering the power station boiler according to the outlet water temperature of the high-pressure heater.
2. The utility boiler low load feedwater return system of claim 1, wherein the feedwater return line assembly comprises:
the return pipeline is respectively communicated with the water inlet of the water feeding pump and the water outlet of the high-pressure heater;
and the return valve is arranged on the return pipeline and used for adjusting the water flow of the return pipeline.
3. The utility boiler low load feedwater return system of claim 1 wherein the high pressure heater is plural;
the feed water return pipeline assembly is at least one and is in matched connection with one or more high-pressure heaters.
4. The utility boiler low load feed water recirculation system of claim 2, wherein a first temperature sensor for detecting the feed water temperature entering the utility boiler is disposed on the pipeline between the high pressure heater and the utility boiler, and the first temperature sensor is electrically connected to the electric control unit of the recirculation valve, so that the electric control unit adjusts the opening of the recirculation valve according to the temperature detected by the first temperature sensor.
5. The utility boiler low-load feed water recirculation system of claim 2 or 4, characterized in that a second temperature sensor for detecting the temperature of the flue gas is arranged at the flue gas inlet of the flue gas treatment device, and the second temperature sensor is electrically connected with the electronic control component in the recirculation valve, so that the electronic control component adjusts the opening of the recirculation valve according to the temperature detected by the second temperature sensor.
6. The utility boiler low-load feedwater return system of claim 2, further comprising a low-pressure heater and a deaerator, wherein steam output by the utility boiler forms condensed water and then enters the feedwater pump through the low-pressure heater and the deaerator in sequence.
7. The utility boiler low load feedwater recirculation system of claim 1, further comprising a de-drum and an economizer located within the utility boiler.
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920808218.8U CN210153770U (en) | 2019-05-29 | 2019-05-29 | Low-load feed water backflow system of power station boiler |
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| Application Number | Priority Date | Filing Date | Title |
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| CN201920808218.8U CN210153770U (en) | 2019-05-29 | 2019-05-29 | Low-load feed water backflow system of power station boiler |
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| CN210153770U true CN210153770U (en) | 2020-03-17 |
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| CN201920808218.8U Active CN210153770U (en) | 2019-05-29 | 2019-05-29 | Low-load feed water backflow system of power station boiler |
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