CN113324238A - Composite hot water recirculation system and method for full-load denitration of supercritical power station boiler - Google Patents
Composite hot water recirculation system and method for full-load denitration of supercritical power station boiler Download PDFInfo
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- CN113324238A CN113324238A CN202110583511.0A CN202110583511A CN113324238A CN 113324238 A CN113324238 A CN 113324238A CN 202110583511 A CN202110583511 A CN 202110583511A CN 113324238 A CN113324238 A CN 113324238A
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 205
- 238000000034 method Methods 0.000 title claims abstract description 23
- 239000002131 composite material Substances 0.000 title claims abstract description 18
- 238000011144 upstream manufacturing Methods 0.000 claims abstract description 29
- 238000004064 recycling Methods 0.000 claims abstract description 5
- 230000001105 regulatory effect Effects 0.000 claims description 32
- 238000003860 storage Methods 0.000 claims description 14
- 238000010992 reflux Methods 0.000 claims description 9
- UGFAIRIUMAVXCW-UHFFFAOYSA-N Carbon monoxide Chemical compound [O+]#[C-] UGFAIRIUMAVXCW-UHFFFAOYSA-N 0.000 abstract description 23
- 239000003546 flue gas Substances 0.000 abstract description 23
- 239000003245 coal Substances 0.000 abstract description 11
- 238000010521 absorption reaction Methods 0.000 abstract description 8
- 230000009286 beneficial effect Effects 0.000 abstract description 2
- 239000000779 smoke Substances 0.000 description 27
- 239000003054 catalyst Substances 0.000 description 9
- 230000000694 effects Effects 0.000 description 3
- MWUXSHHQAYIFBG-UHFFFAOYSA-N nitrogen oxide Inorganic materials O=[N] MWUXSHHQAYIFBG-UHFFFAOYSA-N 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- 238000004891 communication Methods 0.000 description 2
- 230000007547 defect Effects 0.000 description 2
- 230000007613 environmental effect Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- AKEJUJNQAAGONA-UHFFFAOYSA-N sulfur trioxide Chemical compound O=S(=O)=O AKEJUJNQAAGONA-UHFFFAOYSA-N 0.000 description 2
- 229910021529 ammonia Inorganic materials 0.000 description 1
- BIGPRXCJEDHCLP-UHFFFAOYSA-N ammonium bisulfate Chemical compound [NH4+].OS([O-])(=O)=O BIGPRXCJEDHCLP-UHFFFAOYSA-N 0.000 description 1
- 238000010531 catalytic reduction reaction Methods 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000009826 distribution Methods 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000007246 mechanism Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 238000004781 supercooling Methods 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
- F22D1/00—Feed-water heaters, i.e. economisers or like preheaters
- F22D1/16—Feed-water heaters, i.e. economisers or like preheaters with water tubes arranged otherwise than in the boiler furnace, fire tubes, or flue ways
- F22D1/18—Feed-water heaters, i.e. economisers or like preheaters with water tubes arranged otherwise than in the boiler furnace, fire tubes, or flue ways and heated indirectly
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22D—PREHEATING, OR ACCUMULATING PREHEATED, FEED-WATER FOR STEAM GENERATION; FEED-WATER SUPPLY FOR STEAM GENERATION; CONTROLLING WATER LEVEL FOR STEAM GENERATION; AUXILIARY DEVICES FOR PROMOTING WATER CIRCULATION WITHIN STEAM BOILERS
- F22D5/00—Controlling water feed or water level; Automatic water feeding or water-level regulators
- F22D5/26—Automatic feed-control systems
- F22D5/34—Applications of valves
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Exhaust Gas Treatment By Means Of Catalyst (AREA)
- Control Of Steam Boilers And Waste-Gas Boilers (AREA)
Abstract
The invention discloses a composite hot water recirculation system for full-load denitration of a supercritical power station boiler, which comprises: and the water inlet end of the water supply bypass pipeline is communicated with a main water supply pipeline of the boiler positioned at the upstream of the economizer, the water outlet end of the water supply bypass pipeline is connected with a descending pipeline positioned at the outlet of the economizer, and a gate valve and an adjusting valve are arranged on the water supply bypass pipeline. The water supply flow of the water supply bypass pipeline can be adjusted, the cold water flow participating in flue gas heat exchange in the coal economizer is reduced, and the heat absorption capacity of the coal economizer is reduced, so that the inlet flue gas temperature of the denitration device is improved. Discloses a composite hot water recycling method for full-load denitration of a supercritical power station boiler, which comprises the following steps: and water on the main water supply pipeline positioned at the upstream of the inlet of the economizer is distributed to a descending pipeline at the outlet of the economizer, and the distributed water quantity is adjusted. The beneficial effects of reducing the flow of cold water entering the economizer and participating in the heat exchange of the flue gas, reducing the heat absorption capacity of the economizer and improving the inlet flue gas temperature of the denitration device are achieved.
Description
Technical Field
The invention relates to the field of full-load denitration. More specifically, the invention relates to a composite hot water recirculation system and a method for full-load denitration of a supercritical power station boiler.
Background
At present, Selective Catalytic Reduction (SCR) technology is mostly adopted in denitration devices of power station boilers, and the adopted catalyst requires a common working temperature range of 300-400 ℃ (related to coal types, catalyst types and the like). In conventional boiler designs, the following problems can exist: when the unit load is higher, the inlet smoke temperature of the denitration device is just in the normal operation range of the catalyst, and when the unit load is lower, the inlet smoke temperature of the denitration device is lower and is lower than the normal use temperature of the catalyst. If the designed smoke temperature at the inlet of the denitration device is increased to meet the requirement of the catalyst under the condition of low load, the smoke temperature is higher under the condition of high load, so that the exhaust gas temperature is high, the boiler efficiency is low, and the economical efficiency is poor. Therefore, in general, when the boiler is designed, the boiler is designed according to the requirement of lower exhaust gas temperature under the condition of high load, so that the high efficiency of the boiler is ensured, and the economic efficiency of a unit is improved; however, this will cause the utility boiler to operate the denitration device only in a split manner at low load, and thus cannot meet the latest requirement of the emission index of nitrogen oxides in the power plant, because when the flue gas temperature at the inlet of the SCR is too low, the activity of the catalyst is reduced, and the escape of ammonia is increased, so that the catalyst reacts with sulfur trioxide in the flue gas to form ammonium bisulfate, which causes the blockage of downstream equipment such as an air preheater, and even damages the catalyst.
Along with the successive departure of national environmental protection standards and environmental protection policies in recent years, the requirement for the emission of atmospheric pollutants of the thermal power generating unit is more and more strict, meanwhile, in order to respond to the requirement of a national deep peak regulation policy, the deep peak regulation capability of the thermal power generating unit needs to be improved, the grid connection of the thermal power generating unit needs to be realized by a power station boiler, the requirement that the inlet smoke temperature of a denitration device reaches the use temperature of the denitration device is met by the load, and the supercritical thermal power generating unit also needs to adapt to the requirement of the policy and realize the deep peak regulation capability of the thermal power generating unit.
At present, most of power station units can only realize wide-load denitration, and the adopted methods comprise coal economizer grading arrangement, a flue gas bypass system, a coal economizer water side bypass system and the like. The grading economizer has poor high-low load matching performance and cannot meet the requirement of full-load denitration; the flue gas bypass has the defects of poor distribution of a flue gas temperature field, low reliability of a flue gas baffle and the like; the water side bypass of the economizer has the defects of limited temperature raising range, easy vaporization of working medium and the like; the conventional schemes cannot meet the strict national requirements on deep peak regulation of the thermal power generating unit, and the safe and stable improvement of the SCR inlet smoke temperature under the full-load condition cannot be realized.
Disclosure of Invention
An object of the present invention is to solve at least the above problems and to provide at least the advantages described later.
Still another object of the present invention is to provide a combined hot water recirculation system for full load denitration of a supercritical power plant boiler, which can adjust the water supply flow of a water supply bypass pipeline, reduce the flow of cold water entering an economizer for heat exchange with flue gas, reduce the heat absorption capacity of the economizer, and thus increase the inlet flue gas temperature of a denitration device.
When the unit load is lower, the inlet smoke temperature of the denitration device is lower, partial feed water is directly bypassed to a coal economizer downcomer without passing through a coal economizer and is mixed with other working media heated by the original coal economizer, the heat exchange quantity of the coal economizer is reduced, and the inlet smoke temperature of the denitration device is improved.
To achieve these objects and other advantages in accordance with the purpose of the invention, there is provided a combined hot water recirculation system for full load denitration of a supercritical power plant boiler, comprising:
and the water inlet end of the water supply bypass pipeline is communicated with a main water supply pipeline of the boiler positioned at the upstream of the economizer, the water outlet end of the water supply bypass pipeline is connected with a descending pipeline positioned at the outlet of the economizer, and the water supply bypass pipeline is provided with a gate valve and an adjusting valve.
Preferably, the feed water bypass pipeline is further provided with a check valve and a flowmeter at the downstream of the regulating valve.
Preferably, a recirculation line group is further included, which includes:
the water inlet end of the forced recirculation pipeline is connected with the descending pipeline of the outlet of the economizer, the interface of the forced recirculation pipeline is positioned at the upstream of the water outlet end of the water supply bypass pipeline, and the forced recirculation pipeline is provided with a gate valve, an adjusting valve, a check valve and a flowmeter;
the circulating pump, its intake end and play water end correspond respectively and are connected with circulating pump inlet pipeline and circulating pump outlet pipeline, circulating pump inlet pipeline intake end with force recirculation pipeline's play water end intercommunication, the play water end that circulating pump outlet pipeline was said with being located the main water supply pipeline intercommunication in economizer upper reaches, and be located the intake end low reaches of feedwater bypass pipeline, wherein, be equipped with the filter on the circulating pump inlet pipeline, be equipped with flowmeter, governing valve on the circulating pump outlet pipeline, by the check valve.
Preferably, the method further comprises the following steps:
the bottom of the water storage tank is communicated with the water inlet end of the circulating pump inlet pipeline, and a regulating valve and a gate valve are arranged on the circulating pump inlet pipeline between the water storage tank and the forced recirculation pipeline, wherein the regulating valve and the gate valve on the circulating pump inlet pipeline are both positioned at the upstream of the interface of the forced recirculation pipeline and the circulating pump inlet pipeline;
and the water inlet end of the circulating pump recirculation pipeline is communicated with the outlet pipeline of the circulating pump and is positioned at the upstream of the flow meter on the outlet pipeline of the circulating pump, the water outlet end of the circulating pump recirculation pipeline is communicated with the water storage tank, and the circulating pump recirculation pipeline is provided with an adjusting valve.
Preferably, the circulating pump inlet pipeline is provided with circulating pump bypasses which are arranged on two sides of the gate valve of the circulating pump inlet pipeline in parallel, and the circulating pump bypasses are provided with stop valves.
Preferably, the main water supply pipeline is provided with a high-pressure throttle valve at the upstream of the water outlet end of the circulating pump outlet pipeline and the downstream of the water inlet end of the water supply bypass pipeline.
The provided composite hot water recycling method for full-load denitration of the supercritical power station boiler comprises the following steps: and water on the main water supply pipeline positioned at the upstream of the inlet of the economizer is distributed to a descending pipeline at the outlet of the economizer, and the distributed water quantity is adjusted.
Preferably, the method further comprises the following steps: and forcibly circulating and returning the water on the descending pipeline of the coal economizer outlet and positioned at the upstream of the branched inflow part in the method to the main water supply pipeline at the upstream of the coal economizer inlet, adjusting the amount of the forcibly circulated and returned water, and positioning the inflow part of the forcibly circulated and returned water at the downstream of the branched outflow part in the method.
Preferably, a power device for providing circulation reflux power is arranged on the reflux loop of the forced circulation reflux;
parallel loops are added on two sides of the power device to adjust the circulating water quantity on the parallel loops, and a device with a water storage function is arranged on the parallel loops.
Preferably, a high-pressure throttle valve is provided on the main feed water line upstream of the economizer inlet, said high-pressure throttle valve being located downstream of the split inflow in the above-described method.
The invention at least comprises the following beneficial effects:
firstly, when the unit is in a low load state, the water supply flow of a water supply bypass pipeline can be adjusted by opening the gate valve and adjusting the opening of the adjusting valve, the flow of cold water entering the economizer and participating in heat exchange with flue gas is reduced, the heat absorption capacity of the economizer is reduced, and therefore the inlet smoke temperature of the denitration device is improved.
Secondly, when the flow of the water supply bypass pipeline needs to be further increased, more cold water can be shunted to the water supply bypass pipeline through the pressure-building effect of a high-pressure throttle valve on the main water supply pipeline, so that the adjusting capacity is increased, the flow of the cold water entering the economizer and participating in the heat exchange of the flue gas is reduced, the heat absorption capacity of the economizer is reduced, and the inlet smoke temperature of the denitration device is increased.
And thirdly, when the unit operates under a low-load working condition, part of hot water at the outlet of the economizer is led out by a pressure head of the circulating pump and valve group adjustment on the forced recirculation pipeline, flows through the forced recirculation pipeline, the inlet pipeline of the circulating pump, the circulating pump and the outlet pipeline of the circulating pump and returns to the inlet pipeline of the economizer, so that the temperature of the inlet water of the economizer can be increased, the heat exchange end difference of the water and the flue gas of the economizer is reduced, the heat exchange quantity of the flue gas is reduced, and the temperature of the flue gas at the inlet of the denitration device is increased.
Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.
Drawings
Fig. 1 is a schematic connection diagram of a combined hot water recirculation system according to one embodiment of the present invention.
Detailed Description
The present invention is further described in detail below with reference to the attached drawings so that those skilled in the art can implement the invention by referring to the description text.
It is to be noted that the experimental methods described in the following embodiments are all conventional methods unless otherwise specified, and the reagents and materials, if not otherwise specified, are commercially available; in the description of the present invention, the terms indicating orientation or positional relationship are based on the orientation or positional relationship shown in the drawings only for the convenience of description and simplification of description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.
As shown in fig. 1, the present invention provides a composite hot water recirculation system for full-load denitration of a supercritical power station boiler, comprising:
a water inlet end of the feed water bypass pipeline S1 is communicated with a main feed water pipeline S6 of the boiler 102 positioned at the upstream of the economizer 101, a water outlet end of the feed water bypass pipeline S1 is connected with a descending pipeline positioned at the outlet of the economizer 101, and a gate valve 1 and a regulating valve 2 are arranged on the feed water bypass pipeline S1.
In the technical scheme, when the unit is in a low load state, the gate valve 1 is opened, the opening degree of the regulating valve 2 is regulated, the water supply flow of the water supply bypass pipeline S1 can be regulated, the flow of cold water entering the economizer 101 and participating in heat exchange with flue gas is reduced, the heat absorption capacity of the economizer 101 is reduced, and therefore the inlet smoke temperature of the denitration device is increased.
In another technical scheme, a high-pressure throttle valve 9 is arranged on the main water supply pipeline S6 at a position upstream of the water outlet end of the circulating pump outlet pipeline S4 and downstream of the water inlet end of the water supply bypass pipeline S1.
When the opening of the regulating valve 2 of the water supply bypass pipeline S1 is large but the flow rate still needs to be further increased, more cold water can be shunted to the water supply bypass pipeline S1 through the pressure-holding-out function of the high-pressure throttle valve 9 on the main water supply pipeline S6, so that the regulating capacity is increased, the flow rate of the cold water entering the economizer 101 for heat exchange with flue gas is reduced, the heat absorption capacity of the economizer 101 is reduced, and the inlet smoke temperature of the denitration device is increased.
In another technical scheme, a check valve 3 and a flow meter 4 are further arranged on the feed water bypass pipeline S1 and are positioned downstream of the regulating valve 2. The check valve 3 can prevent water from flowing backwards, and the flow meter 4 can count the water flow to assist in flow regulation.
In another aspect, a recirculation circuit assembly is provided, comprising:
a forced recirculation pipeline S2, the water inlet end of which is connected with the descending pipeline of the outlet of the economizer 101, and the interface of which is positioned at the upstream of the water outlet end of the feed water bypass pipeline S1, wherein the forced recirculation pipeline S2 is provided with a gate valve 5, a regulating valve 6, a check valve 7 and a flowmeter 8;
the circulating pump 103, its water inlet end and play water end correspond respectively and are connected with circulating pump inlet pipeline S3 and circulating pump outlet pipeline S4, circulating pump inlet pipeline S3 water inlet end with force recirculation pipeline S2 ' S play water end intercommunication, circulating pump outlet pipeline S4 ' S play water end with be located the main water supply pipeline S6 intercommunication on economizer 101 upper reaches, and be located feedwater bypass pipeline S1 ' S the water inlet end low reaches, wherein, be equipped with filter 14 on the circulating pump inlet pipeline S3, be equipped with flowmeter 16, governing valve 17 on the circulating pump outlet pipeline S4, stop check valve 18.
In the above technical solution, the operation of the recirculation route group is as follows: when the unit operates under a low-load working condition, the gate valve 5 on the forced recirculation pipeline S2 is opened simultaneously through the pressure head of the circulating pump 103, the opening degree of the regulating valve 6 is gradually and slowly increased, part of hot water at the outlet of the economizer 101 is led out, flows through the forced recirculation pipeline S2, the circulating pump inlet pipeline S3, the circulating pump 103 and the circulating pump outlet pipeline S4 and returns to the inlet pipeline of the economizer 101, the inlet water temperature of the economizer 101 can be increased, the heat exchange end difference between the economizer 101 water and flue gas is reduced, the heat exchange quantity of the flue gas is reduced, and the inlet smoke temperature of the denitration device is increased.
In another technical solution, the method further comprises:
a water storage tank 104, the bottom of which is communicated with the water inlet end of the circulating pump inlet pipeline S3, and a regulating valve 11 and a gate valve 12 are arranged on the circulating pump inlet pipeline S3 between the water storage tank 104 and the forced recirculation pipeline S2, wherein the regulating valve 11 and the gate valve 12 on the circulating pump inlet pipeline S3 are both positioned at the interface upstream of the forced recirculation pipeline S2 and the circulating pump inlet pipeline S3; a circulation pump recirculation line S5 having an inlet end in communication with the circulation pump outlet line S4 and upstream of the flow meter 16 on the circulation pump outlet line S4, the outlet end of the circulation pump recirculation line S5 in communication with the water reservoir 104, and the circulation pump recirculation line S5 having a regulating valve 19 thereon.
In the above solution, the circulation pump recirculation line S5 is arranged between the circulation pump 103 and the water storage tank 104, on which the regulating valve 19 is provided, which functions to meet the requirement of minimum flow of the circulation pump 103. The control valve 11 of the circulation pump inlet line S3 is opened to adjust the opening as necessary to match the flow rate of the forced recirculation line S2 with the flow rate of the water entering the circulation pump inlet line S3 from the reservoir tank 104.
In another technical scheme, a circulation pump bypass is arranged on the circulation pump inlet pipeline S3 and positioned on two sides of the gate valve 12, and a stop valve 13 is arranged on the circulation pump bypass. This shut-off valve 13 is normally closed. As a bypass, warm-pipe water of the circulation pump 103 can enter the water storage tank 104 through this bypass when the starting system is not in operation and the gate valve 12 on the circulation pump inlet line S3 is in a closed state due to a failure.
The provided composite hot water recycling method for full-load denitration of the supercritical power station boiler comprises the following steps: the water on the main water supply pipe S6 located upstream of the inlet of the economizer 101 is branched to the descending pipe of the outlet of the economizer 101, and the branched water amount is adjusted.
In the above technical solution, the main water feed pipe S6 of the boiler 102 inputs cold water into the economizer 101, hot water flows out from the outlet of the economizer 101 after heat exchange by water smoke, and enters the boiler 102, when the unit load is high, the inlet smoke temperature of the denitration device is just in the normal operation range of the catalyst, and when the unit load is low, the inlet smoke temperature of the denitration device is low, and by making part of the feed water directly bypass to the downcomer of the economizer 101 without passing through the economizer 101 and mix with other working media heated by the original economizer 101, the heat exchange amount of the economizer 101 is reduced, and the inlet smoke temperature of the denitration device is increased.
In another solution, a high-pressure throttle valve 9 is provided on the main feed water line S6 upstream of the inlet of the economizer 101, said high-pressure throttle valve 9 being located downstream of the split inflow in the above solution.
In the above technical scheme, when the flow rate of the backflow needs to be further increased, more cold water can be shunted to the backflow route through the pressure-holding-out function of the high-pressure throttle valve 9 on the main water supply pipeline S6, so that the adjusting capacity is increased, the flow rate of the cold water entering the economizer 101 and participating in heat exchange with the flue gas is reduced, the heat absorption capacity of the economizer 101 is reduced, and the inlet smoke temperature of the denitration device is increased.
In another technical solution, the method further comprises: the water at the outlet of the economizer 101 and upstream of the inlet of the partial flow in the above-mentioned scheme is forcibly recirculated to the main water supply line S6 upstream of the inlet of the economizer 101, the amount of water forcibly recirculated is adjusted, and the inlet of the forcible recirculation is downstream of the outlet of the partial flow in the above-mentioned scheme.
In the technical scheme, part of hot water at the outlet of the economizer 101 is led out and enters the inlet pipeline of the economizer 101 through forced recirculation and backflow, so that the water temperature at the inlet of the economizer 101 is increased, the heat exchange end difference of the economizer 101 is reduced, and the smoke temperature at the inlet of the denitration device is increased.
In another technical scheme, a power device for providing circulation reflux power is arranged on a reflux loop of the forced circulation reflux;
parallel loops are added on two sides of the power device to adjust the circulating water quantity on the parallel loops, and a device with a water storage function is arranged on the parallel loops.
In the above technical solution, the power plant usually has the minimum delivery capacity, if the amount of water of the forced circulation return flow does not reach the minimum delivery capacity of the power plant, a method of parallel loop of the power plant is adopted, and when the amount of water of the forced circulation return flow is lower than the minimum flow of the power plant, the flow of the parallel loop is adjusted to match the flow of the forced circulation return flow.
The technical scheme can also comprise the following technical details so as to better realize the technical effects: the composite hot water recycling system and method for realizing full-load denitration according to the patent are described in detail with reference to the attached drawing 1.
A composite hot water recirculation system for realizing full-load denitration comprises a feed water bypass pipeline S1, a gate valve 1, a regulating valve 2, a check valve 3 and a flowmeter 4, wherein the gate valve 1, the regulating valve 2, the check valve 3 and the flowmeter are arranged on the feed water bypass pipeline; a forced recirculation line S2 and a gate valve 5, a regulating valve 6, a check valve 7, a flow meter 8 arranged thereon; a circulating pump inlet pipeline S3 and a regulating valve 11, a gate valve 12, a bypass and stop valve 13 and a filter 14 which are arranged on the circulating pump inlet pipeline; the circulating pump outlet line S4 and the flow meter 16, the regulating valve 17, the stop check valve 18 disposed thereon; the circulation pump recirculation line S5 and the regulating valve 19 arranged thereon; a circulating pump 103, a high-pressure throttle valve 9 on a main water supply pipeline S6, a check valve 10 and a working medium temperature measuring point 23 on an outlet descending pipe of the economizer 101.
The gate valve 1, the regulating valve 2, the gate valve 5, the regulating valve 6, the high-pressure throttle valve 9, the regulating valve 11, the regulating valve 17, the stop check valve 18 and the regulating valve 19 all comprise valve bodies and electric actuating mechanisms; the flow meters 4 and 8 comprise flow orifice plates, primary valves, secondary valves, transmitters, instrument valves, drain valves and the like.
In the starting process of the unit, when the inlet smoke temperature of the denitration device is lower than the required smoke temperature for putting the denitration device into use under the low-load working condition, the water supply bypass pipeline S1 enables part of water supply to directly bypass to the downcomer of the economizer 101 without passing through the economizer 101 system and to be mixed with other working media heated by the original economizer 101 through the control of the valve group S1, so that the heat exchange quantity of the economizer 101 system is reduced, and the inlet smoke temperature of the denitration device is increased.
After the forced recirculation pipeline S2 is put into the water supply bypass pipeline S1, part of hot water at the outlet of the economizer 101 is led out through the control of a valve group on S2, is connected to an interface of an inlet pipeline S3 of the circulating pump through the forced recirculation pipeline S2, and enters an inlet pipeline of the economizer 101 through the circulating pump 103 and an outlet pipeline S4 of the circulating pump, so that the water temperature at the inlet of the economizer 101 system is increased, the heat exchange end difference of the economizer 101 system is reduced, and the smoke temperature at the inlet of the denitration device is increased.
After the composite hot water recirculation system is put into operation, the opening of the high-pressure throttle valve 9 is gradually reduced to play a role in pressure building, the flow of forced recirculation hot water and the flow of a cold water bypass are improved through the opening of the regulating valve 6, and the temperature of inlet smoke of the denitration device can be greatly improved. The opening degree of the regulating valve 11 is controlled to keep the water level of the water storage tank 104 after the steam production is increased in the unit load-up process.
After the composite hot water recirculation system is put into operation, when the load of a unit is gradually increased, the temperature of smoke at the inlet of the denitration device is continuously increased, the required cold water flow of the water supply bypass pipeline S1 and the required hot water flow of the forced recirculation pipeline S2 are reduced, and the S1 and S2 working medium flows are adjusted through the control of the S1 and S2 upper valve groups.
After the operation of the composite hot water recirculation system, until the boiler 102 is switched from wet operation to direct current operation, the flow rate is controlled and adjusted through the valve banks of the S1 and S2, and when the flow rate of the circulating pump 103 is close to the minimum flow rate, the adjusting valve 19 is opened to maintain the flow rate of the circulating pump 103 to be larger than the minimum flow rate required by the circulating pump 103.
After the composite hot water recirculation system is put into operation, along with further increase of load, when the requirement of inlet smoke temperature of the denitration device can be met only through the water supply bypass pipeline S1, the valve group on the S2 pipeline is closed. As the load further increases, the inlet flue gas temperature of the denitrator further increases and may be progressively reduced until the valve train on the S1 line is closed. At this time, the complex hot water recirculation system is disconnected.
When the composite hot water recirculation system is put into operation, hot water at the outlet of the economizer 101 is monitored to keep a certain supercooling degree through a working medium temperature measuring point of a down pipe at the outlet of the economizer 101.
By the aid of the composite hot water recirculation system and the method, inlet smoke temperature of the denitration device of the supercritical boiler 102 can be greatly increased, the denitration device is put into a grid connection of a unit and in a full load range, and deep peak regulation adaptability of the unit is improved.
While embodiments of the invention have been described above, it is not limited to the applications set forth in the description and the embodiments, which are fully applicable in various fields of endeavor to which the invention pertains, and further modifications may readily be made by those skilled in the art, it being understood that the invention is not limited to the details shown and described herein without departing from the general concept defined by the appended claims and their equivalents.
Claims (10)
1. Composite hot water recirculation system of supercritical power plant boiler full load denitration, its characterized in that includes:
and the water inlet end of the water supply bypass pipeline is communicated with a main water supply pipeline of the boiler positioned at the upstream of the economizer, the water outlet end of the water supply bypass pipeline is connected with a descending pipeline positioned at the outlet of the economizer, and the water supply bypass pipeline is provided with a gate valve and an adjusting valve.
2. The combined hot water recirculation system for full load denitration of supercritical power plant boiler as claimed in claim 1, characterized in that a check valve and a flow meter are further provided on the feed water bypass line downstream of the regulating valve.
3. The combined hot water recirculation system for full load denitration of supercritical power plant boiler as claimed in claim 1, further comprising a recirculation piping group comprising:
the water inlet end of the forced recirculation pipeline is connected with the descending pipeline of the outlet of the economizer, the interface of the forced recirculation pipeline is positioned at the upstream of the water outlet end of the water supply bypass pipeline, and the forced recirculation pipeline is provided with a gate valve, an adjusting valve, a check valve and a flowmeter;
the circulating pump, its intake end and play water end correspond respectively and are connected with circulating pump inlet pipeline and circulating pump outlet pipeline, circulating pump inlet pipeline intake end with force recirculation pipeline's play water end intercommunication, the play water end that circulating pump outlet pipeline was said with being located the main water supply pipeline intercommunication in economizer upper reaches, and be located the intake end low reaches of feedwater bypass pipeline, wherein, be equipped with the filter on the circulating pump inlet pipeline, be equipped with flowmeter, governing valve on the circulating pump outlet pipeline, by the check valve.
4. The combined hot water recirculation system for full load denitration of a supercritical power plant boiler as claimed in claim 3, further comprising:
the bottom of the water storage tank is communicated with the water inlet end of the circulating pump inlet pipeline, and a regulating valve and a gate valve are arranged on the circulating pump inlet pipeline between the water storage tank and the forced recirculation pipeline, wherein the regulating valve and the gate valve on the circulating pump inlet pipeline are both positioned at the upstream of the interface of the forced recirculation pipeline and the circulating pump inlet pipeline;
and the water inlet end of the circulating pump recirculation pipeline is communicated with the outlet pipeline of the circulating pump and is positioned at the upstream of the flow meter on the outlet pipeline of the circulating pump, the water outlet end of the circulating pump recirculation pipeline is communicated with the water storage tank, and the circulating pump recirculation pipeline is provided with an adjusting valve.
5. The combined hot water recirculation system for full-load denitration of the supercritical power station boiler according to claim 4, characterized in that a circulation pump bypass is connected in parallel on the circulation pump inlet pipeline at two sides of the gate valve, and a stop valve is arranged on the circulation pump bypass.
6. The combined hot water recirculation system for full load denitration of supercritical power plant boiler as claimed in claim 3, characterized in that high pressure throttle valves are provided on the main water supply pipe at positions upstream of the outlet end of the circulating pump outlet pipe and downstream of the inlet end of the water supply bypass pipe.
7. The composite hot water recycling method for full-load denitration of the supercritical power station boiler is characterized by comprising the following steps of: and water on the main water supply pipeline positioned at the upstream of the inlet of the economizer is distributed to a descending pipeline at the outlet of the economizer, and the distributed water quantity is adjusted.
8. The combined hot water recirculation method for full load denitration of a supercritical power plant boiler as claimed in claim 7, further comprising: forcing a recirculation of water on the downcomer pipe at the exit of the economizer and upstream of the split inflow in claim 7 to the main feed water pipe upstream of the entrance of the economizer, adjusting the amount of water forced to recirculate, and forcing the inflow of recirculation to be downstream of the split outflow in claim 7.
9. The combined hot water recirculation method for full-load denitration of a supercritical power plant boiler as claimed in claim 8, characterized in that a power device for providing circulation reflux power is arranged on the reflux loop of the forced circulation reflux;
parallel loops are added on two sides of the power device to adjust the circulating water quantity on the parallel loops, and a device with a water storage function is arranged on the parallel loops.
10. The combined hot water recirculation method for full-load denitration of a supercritical power plant boiler in claim 7, characterized in that a high-pressure throttle valve is provided on the main water feed pipe upstream of the economizer inlet, the high-pressure throttle valve being located downstream of the split inflow in claim 7.
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Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103953913A (en) * | 2014-03-28 | 2014-07-30 | 上海发电设备成套设计研究院 | Heat-exchange adjustable economizer system for whole-process operation of denitration equipment |
| CN104028104A (en) * | 2014-06-24 | 2014-09-10 | 中国电力工程顾问集团华东电力设计院 | Denitration device with economizer re-circulating system and generator unit |
| CN206904939U (en) * | 2017-07-12 | 2018-01-19 | 湘潭大学 | A kind of electrical heating pure steam generator |
| CN108679594A (en) * | 2018-04-17 | 2018-10-19 | 华电电力科学研究院有限公司 | Station boiler is adjustable high temperature dust pelletizing system and application process |
| US20190170020A1 (en) * | 2016-06-23 | 2019-06-06 | Lidao ZHANG | Gas turbine and pressurized water reactor steam turbine combined circulation system |
| CN215411832U (en) * | 2021-05-27 | 2022-01-04 | 北京巴布科克·威尔科克斯有限公司 | Composite hot water recirculation system for full-load denitration of supercritical power station boiler |
-
2021
- 2021-05-27 CN CN202110583511.0A patent/CN113324238B/en active Active
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103953913A (en) * | 2014-03-28 | 2014-07-30 | 上海发电设备成套设计研究院 | Heat-exchange adjustable economizer system for whole-process operation of denitration equipment |
| CN104028104A (en) * | 2014-06-24 | 2014-09-10 | 中国电力工程顾问集团华东电力设计院 | Denitration device with economizer re-circulating system and generator unit |
| US20190170020A1 (en) * | 2016-06-23 | 2019-06-06 | Lidao ZHANG | Gas turbine and pressurized water reactor steam turbine combined circulation system |
| CN206904939U (en) * | 2017-07-12 | 2018-01-19 | 湘潭大学 | A kind of electrical heating pure steam generator |
| CN108679594A (en) * | 2018-04-17 | 2018-10-19 | 华电电力科学研究院有限公司 | Station boiler is adjustable high temperature dust pelletizing system and application process |
| CN215411832U (en) * | 2021-05-27 | 2022-01-04 | 北京巴布科克·威尔科克斯有限公司 | Composite hot water recirculation system for full-load denitration of supercritical power station boiler |
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