CN213421062U - Power plant boiler full load denitration is synthesized and is optimized device - Google Patents
Power plant boiler full load denitration is synthesized and is optimized device Download PDFInfo
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- CN213421062U CN213421062U CN202022446041.7U CN202022446041U CN213421062U CN 213421062 U CN213421062 U CN 213421062U CN 202022446041 U CN202022446041 U CN 202022446041U CN 213421062 U CN213421062 U CN 213421062U
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Abstract
The utility model relates to a power plant boiler full load denitration is synthesized and is optimized device, including setting up the low temperature reheater in the flue before the back shaft of the two flues of afterbody of unit equipment, set up low temperature superheater, the economizer in the flue behind the back shaft of the two flues of afterbody, separate through the divider superheater between low temperature reheater and low temperature superheater, the economizer, low temperature reheater and economizer lower part all are provided with gas baffle, pass through the pipe connection between the economizer entry and the stove water circulation pump export. The device can realize full-load denitration of the power station boiler without equipment transformation by adopting a comprehensive optimization technology according to the inherent characteristics of the power station boiler equipment. The implementation of the comprehensive optimization technology can save technical improvement cost, avoid the problems of exhaust gas temperature rise and boiler efficiency reduction caused by untight baffle when a flue bypass of the economizer is additionally installed, and simultaneously avoid the problem that the safe operation of a unit is influenced by the boiling working condition of working media in the economizer when the feed water bypass of the economizer is arranged.
Description
Technical Field
The utility model belongs to the technical field of power plant boiler denitration safety economic operation research science and technology and specifically relates to a power plant boiler full load denitration comprehensive optimization device.
Background
With the implementation of the emission standard of atmospheric pollutants of thermal power plants (GB 13223-2011), the environmental protection requirement of the utility boiler is more and more strict, and the full-load denitration of the utility boiler becomes a bottleneck restricting the environmental protection operation of the power station. The denitration device exit event caused by the fact that the flue gas temperature cannot meet the requirement is easy to happen to the unit under the low-load working condition, and the method of additionally installing an economizer flue bypass or arranging an economizer water supply bypass is generally adopted at present to meet the requirement of low-load denitration.
The scheme of the prior art is briefly described as follows:
(1) and a coal economizer flue bypass is additionally arranged. A bypass flue is additionally arranged in front of an inlet of the economizer, and a baffle is arranged on the bypass flue; under the low-load working condition of the boiler, when the temperature of the flue gas is lower than the lowest ammonia injection temperature of the catalyst, the bypass baffle is opened to ensure that the flue gas of the boiler directly enters the SCR denitration device without being cooled by the economizer so as to obtain sufficient high-temperature flue gas.
(2) And a coal economizer water supply bypass is arranged. Before the inlet header of the economizer, part of the water supply pipeline is directly short-circuited with the outlet header of the economizer to be led to a downcomer. And the water supply flow of the bypass is adjusted by the adjusting valve during low load, so that the water inflow of the economizer is reduced to reduce the heat absorption of the economizer, the flue gas temperature at the outlet of the economizer is increased, and the flue gas temperature required by ammonia injection is reached.
Objective disadvantages of the prior art:
(1) the defect of the additional installation of the economizer flue bypass is as follows: the cost is that the heat exchange quantity of the feed water in the economizer and the boiler efficiency are sacrificed, the requirement on the reliability of the flue gas baffle is very high, and the flue gas temperature is increased and the boiler efficiency is reduced due to the untight baffle.
(2) The coal economizer water supply bypass is arranged: the method has limited regulation on the smoke temperature, and the safe operation of the unit is easily influenced by the boiling working condition of the working medium in the economizer.
SUMMERY OF THE UTILITY MODEL
The utility model aims at solving the defect that prior art exists, provide a power plant boiler full load denitration comprehensive optimization device.
In order to realize the purpose, the utility model discloses a technical scheme as follows:
the utility model provides a power plant boiler full load denitration comprehensive optimization device, includes the low temperature reheater in the preceding flue of the back shaft of the two flues in afterbody of setting up at unit equipment, sets up low temperature superheater, economizer in the back shaft back flue of the two flues in afterbody, separates through divider wall superheater between low temperature reheater and low temperature superheater, the economizer.
Further, the lower parts of the low-temperature reheater and the economizer are provided with flue gas baffles.
Further, the inlet of the economizer is connected with the outlet of the boiler water circulating pump through a pipeline.
Further, the low-temperature reheater is connected with the low re-outlet header, the low-temperature superheater is connected with the low through outlet header, and the economizer is connected with the economizer outlet header.
Further, reheater desuperheated water is arranged at a low-temperature reheater outlet.
The utility model has the advantages that: the device can realize full-load denitration of the power station boiler without equipment transformation by adopting a comprehensive optimization technology according to the inherent characteristics of the power station boiler equipment. The implementation of the comprehensive optimization technology can save technical improvement cost, avoid the problems of exhaust gas temperature rise and boiler efficiency reduction caused by untight baffle when a flue bypass of the economizer is additionally installed, and simultaneously avoid the problem that the safe operation of a unit is influenced by the boiling working condition of working media in the economizer when the feed water bypass of the economizer is arranged.
Drawings
Fig. 1 is a schematic structural diagram of the present invention.
Detailed Description
As shown in fig. 1, the utility boiler full-load denitration comprehensive optimization device comprises a low-temperature reheater 2 arranged in a rear shaft front flue 1 of a tail double flue of a unit device, and a low-temperature superheater 4 and an economizer 5 arranged in a rear shaft rear flue 3 of the tail double flue, wherein the low-temperature reheater 2, the low-temperature superheater 4 and the economizer 5 are separated by a partition wall superheater.
The lower parts of the low-temperature reheater 2 and the economizer 5 are both provided with a flue gas baffle 7, and the inlet of the economizer 5 is connected with the outlet of the boiler water circulating pump through a pipeline. The low-temperature reheater 2 is connected with a low re-outlet header 8, the low-temperature superheater 4 is connected with a low over-outlet header 9, and the economizer 5 is connected with an economizer outlet header 10. Wherein the reheater desuperheated water is arranged at the outlet of the low-temperature reheater.
A certain unit has the characteristics described in the summary of the utility boiler equipment of the technical scheme on the equipment. By adopting a comprehensive optimization technology of full-load denitration of a power station boiler, multiple tests in cold start of a unit can realize that the temperature of denitration inlet smoke reaches above 300 ℃ at the initial stage of grid connection, and the method is implemented as follows:
the coal is reasonably distributed, the coal mill is optimized to be started, and the flue gas volume and the temperature of the flue gas at the outlet of the hearth are improved. According to the coal storage condition of a coal yard, the coal blending mode is fully considered, the heating value of the coal as fired is calculated, the heating value of the coal as fired is reduced as much as possible on the premise of ensuring stable combustion, and the second and third pulverizing systems are started as early as possible to improve the flue gas volume and the temperature of the flue gas at the outlet of a hearth.
The adjustment of the tail flue gas baffle 7 is optimized, the heat absorption of the economizer 5 is reduced, and the denitration inlet flue gas temperature is improved. The economizer of the power station boiler is only arranged in the rear vertical shaft rear flue of the tail double flue, and the middle part of the economizer is separated by a partition wall superheater; in the process of constant-speed warming-up of the steam turbine, the flue gas amount passing through the economizer 5 side is reduced by adopting a mode of closing the economizer 5 side flue gas baffle 7 (the minimum can be closed to 10%) and fully opening the reheater side flue gas baffle 7, so that the heat absorption of the economizer to the flue gas is reduced, and the flue gas temperature at a denitration inlet is improved. The method has the effect similar to that of the flue gas bypass with the coal economizer, but can avoid the problems of smoke exhaust temperature rise and boiler efficiency reduction caused by untight bypass baffle.
The steam temperature control is optimized, the water supply temperature is improved, the heat absorption of the economizer 5 is reduced, and the denitration inlet smoke temperature is improved. After the steam turbine washes the car, warms up and the unit is connected to the power grid, the steam temperature is synchronously heated according to a unit starting temperature rise rate curve so as to improve the temperature of denitration inlet smoke. During the period of flushing and warming up the steam turbine, gradually increasing the temperature of the over-heated steam and the reheated steam to 420 ℃ according to a specified heating rate (not more than 1 ℃/min), and continuously increasing the temperature after warming up is finished, and gradually increasing the temperature of the over-heated steam and the reheated steam to 450 ℃; after the unit is connected to the power grid, the temperature of the superheated steam and the reheated steam is gradually increased to 500 ℃. When the rotating speed of the host reaches 1500rpm/min, the random input is added at a low level; if the unit high-medium pressure cylinder combined starting mode is adopted, the high pressure can be put in at 3000rpm/min (under the medium pressure cylinder starting mode, the high pressure can be put in as early as possible after the unit cylinder is cut). For example, under a combined starting mode of a high and medium pressure cylinder of the unit, after the initial load warming is finished, the complete investment of the high and low pressure cylinders is ensured (under the starting mode of the medium pressure cylinder, the complete investment of the 150MW high pressure cylinder is ensured); when the pressure of the four pumps reaches 0.25MPa, the four pumps are ensured to be completely put into the deaerator after being heated; the water supply temperature is improved, the heat absorption of the economizer is reduced, and the denitration inlet smoke temperature is improved.
Optimize the operation of boiler water circulating pump, improve denitration entry gas temperature. When the boiler operates under low load in a wet state, the operation of the boiler water circulating pump is very important for improving the water temperature at the inlet of the economizer 5, under the condition that the boiler water circulating pump does not exceed the output, the boiler water recirculation flow is improved as much as possible, the supplemented water supply quantity is reduced, and the effect of improving the smoke temperature at the denitration inlet is obvious. The method has the effect similar to that of the coal economizer water supply bypass, but can avoid the influence on the safe operation of the unit caused by the boiling working condition of the working medium in the coal economizer.
The operation before and after the wet state is changed into the dry state of the power station boiler is optimized, and the reduction range of the denitration inlet smoke temperature is reduced. The unit is connected with the power grid and then the load of the unit rises, the high-side pressure reducing valve is closed, the water supply temperature is reduced, the steam flow is increased, the temperature of the denitration inlet smoke is reduced, and the temperature of the denitration inlet smoke is reduced by about 10-15 ℃ when the denitration inlet smoke is in a dry state. In order to avoid the denitration inlet smoke temperature from being reduced to below 300 ℃ after grid connection, the method comprises the following steps: after grid connection, the temperature of main reheat steam is gradually increased to be more than 500 ℃, and a third set of pulverizing system is started and boiler combustion is increased in time before a wet state is converted into a dry state.
When the unit is subjected to deep peak shaving, the flue gas quantity passing through the economizer side is reduced by adopting a mode of closing the flue gas baffle at the side of the economizer 5 (the minimum can be closed to 10 percent) and fully opening the flue gas baffle at the side of the low-temperature reheater 2, so that the heat absorption of the economizer 5 to the flue gas is reduced, the flue gas temperature at a denitration inlet is improved, and the low-load denitration commissioning requirement is met; if the unit needs to be switched into wet operation, the recycling flow of the furnace water is improved as much as possible under the condition that the furnace water circulating pump does not exceed the output, the effect of improving the smoke temperature of the denitration inlet is obvious, the adjustment of the smoke baffle and the adjustment of the furnace water circulating pump are combined, and the denitration commissioning requirement of the unit during wet operation can be met.
The device can realize full-load denitration of the power station boiler without equipment transformation by adopting a comprehensive optimization technology according to the inherent characteristics of the power station boiler equipment. The implementation of the comprehensive optimization technology can save technical improvement cost, avoid the problems of exhaust gas temperature rise and boiler efficiency reduction caused by untight baffle when a flue bypass of the economizer is additionally installed, and simultaneously avoid the problem that the safe operation of a unit is influenced by the boiling working condition of working media in the economizer when the feed water bypass of the economizer is arranged.
The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the above embodiments, and that the principles of the present invention may be applied to any other embodiment without departing from the spirit and scope of the present invention. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (5)
1. The utility model provides a power plant boiler full load denitration comprehensive optimization device which characterized in that, including set up the low temperature reheater in the preceding flue of the back shaft of the two flues in afterbody of unit equipment, set up low temperature superheater, the economizer in the back shaft back flue of the two flues in afterbody, separate through the divider superheater between low temperature reheater and low temperature superheater, the economizer.
2. The utility boiler full-load denitration comprehensive optimization device of claim 1, characterized in that the lower parts of the low-temperature reheater and the economizer are provided with flue gas baffles.
3. The utility boiler full-load denitration comprehensive optimization device of claim 1, characterized in that the economizer inlet and the boiler water circulating pump outlet are connected through a pipeline.
4. The utility boiler full-load denitration comprehensive optimization device of claim 1, characterized in that the low-temperature reheater is connected with the low re-outlet header, the low-temperature superheater is connected with the low-superheat outlet header, and the economizer is connected with the economizer outlet header.
5. The utility boiler full-load denitration comprehensive optimization device of claim 1, characterized in that reheater desuperheating water is arranged at the outlet of the low-temperature reheater.
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| CN202022446041.7U CN213421062U (en) | 2020-10-29 | 2020-10-29 | Power plant boiler full load denitration is synthesized and is optimized device |
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| CN202022446041.7U CN213421062U (en) | 2020-10-29 | 2020-10-29 | Power plant boiler full load denitration is synthesized and is optimized device |
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113813755A (en) * | 2021-08-25 | 2021-12-21 | 华能沁北发电有限责任公司 | Denitration full-load commissioning control method for coal-fired unit |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113813755A (en) * | 2021-08-25 | 2021-12-21 | 华能沁北发电有限责任公司 | Denitration full-load commissioning control method for coal-fired unit |
| CN113813755B (en) * | 2021-08-25 | 2023-11-28 | 华能沁北发电有限责任公司 | Denitration full-load operation control method for coal-fired unit |
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