CN115978526A - Automatic adjusting method of steam feed water pump near critical point of opening recirculation valve - Google Patents
Automatic adjusting method of steam feed water pump near critical point of opening recirculation valve Download PDFInfo
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- CN115978526A CN115978526A CN202211565954.8A CN202211565954A CN115978526A CN 115978526 A CN115978526 A CN 115978526A CN 202211565954 A CN202211565954 A CN 202211565954A CN 115978526 A CN115978526 A CN 115978526A
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- steam
- feed water
- recirculation valve
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- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 title claims abstract description 90
- 238000000034 method Methods 0.000 title claims abstract description 26
- 230000001105 regulatory effect Effects 0.000 description 5
- 238000011217 control strategy Methods 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification 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
- F22D5/00—Controlling water feed or water level; Automatic water feeding or water-level regulators
- F22D5/26—Automatic feed-control systems
- F22D5/32—Automatic feed-control systems influencing the speed or delivery pressure of the feed pumps
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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
- 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)
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- Thermal Sciences (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Control Of Turbines (AREA)
Abstract
The invention discloses an automatic adjusting method of a steam feed water pump near a critical point of opening a recirculation valve, which comprises the following steps: when the critical point that the recirculation valves of the two steam-driven feed water pumps are opened simultaneously is reached, a rotating speed offset is set for one of the steam-driven feed water pumps, so that the inlet flow of the corresponding steam pump is slowly increased and is far away from the critical point for opening the corresponding recirculation valve, and only the other steam-driven feed water pump is allowed to slowly open the corresponding recirculation valve. The automatic adjusting method of the steam-driven feed water pump near the critical point of the opening recirculation valve provided by the invention can realize that the main feed water flow fluctuation is not too large when the supercritical coal-fired unit is opened near the critical point of the recirculation valve in the unit load change process by opening the single recirculation valve, and is particularly suitable for the supercritical coal-fired unit with two 50% capacity steam-driven feed water pumps configured as the feed water pump.
Description
Technical Field
The invention belongs to the technical field of industrial automation, and particularly relates to an automatic adjusting method of a steam feed water pump near a critical point of an opening recirculation valve.
Background
In recent years, thermal power generating units in China develop rapidly, and supercritical and ultra-supercritical coal-fired units become main power generating machines in China. For the ultra-supercritical coal-fired unit, the load (BD) and feed water flow target value curve is shown in FIG. 1, and it can be seen from FIG. 1 that the feed water flow is about 1240t/h around 500MW, and the average outlet flow of each steam pump is about 620t/h when two steam pumps are simultaneously put into automatic operation. As shown in the figures 2-3, when the inlet flow of the steam pump is less than 620t/h, the recirculation valve of the steam feed water pump needs to be opened, the opening degree of the recirculation valve is maximum (100%), and the inlet flow of the air pump is 380t/h. When two recirculation valves of the steam feed water pump are opened simultaneously, great disturbance is generated on the main feed water flow, and the hidden danger that the main feed water flow is low in MFT exists.
The above information disclosed in this background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known to a person of ordinary skill in the art.
Disclosure of Invention
In order to solve the technical problems in the prior art, the invention aims to provide an automatic adjusting method of a steam feed water pump near a critical point of opening a recirculation valve.
In order to achieve the purpose and achieve the technical effect, the invention adopts the technical scheme that:
the automatic regulating method of the steam feed water pump near the critical point of opening the recirculation valve comprises the following steps:
when the critical point that the recirculation valves of the two steam-driven feed water pumps are opened simultaneously is reached, a rotating speed offset is set for one of the steam-driven feed water pumps, so that the inlet flow of the corresponding steam pump is slowly increased and is far away from the critical point for opening the corresponding recirculation valve, and only the other steam-driven feed water pump is allowed to slowly open the corresponding recirculation valve.
Furthermore, a rotating speed offset is set for one of the steam-driven feed-water pumps, and the corresponding recirculation valve which is slowly opened by the other steam-driven feed-water pump needs to simultaneously meet the following conditions:
1) Both the boiler main control instruction and the unit load instruction are smaller than a critical value;
2) The inlet flows of the steam pumps corresponding to the two steam-driven water feeding pumps are both smaller than a certain value and are positioned near a critical point of a recirculation valve to be opened;
3) The recirculation valves corresponding to the two steam feed water pumps are not opened;
4) The rotating speeds of the two steam-driven water feeding pumps are in an automatic control mode;
5) The recirculation valve, which can be slowly opened, is in an automatic control mode.
Furthermore, a rotational speed offset is set for one of the steam-driven feed-water pumps, and only the other steam-driven feed-water pump is required to slowly open the corresponding recirculation valve, which simultaneously satisfies the following conditions:
1) The boiler master control instruction and the unit load instruction are both less than 500MW;
2) The inlet flows of the steam pumps corresponding to the two steam-driven water feeding pumps are both smaller than 660t/h and are positioned near a critical point of a recirculation valve to be opened;
3) The maximum values of the opening degrees of the recirculation valves corresponding to the two steam-driven water-feeding pumps are both less than 3%, and at the moment, the recirculation valves corresponding to the two steam-driven water-feeding pumps are not opened;
4) The rotating speeds of the two steam-driven water feeding pumps are in an automatic control mode;
5) The recirculation valve, which can be slowly opened, is in an automatic control mode.
The rotating speed offset is 50r/min, and the rising speed is 2-3 rpm/s.
When the load instruction of the unit is larger than 520MW, the target value of the water supply flow is far away from the critical point of the opening of the recirculation valves of the two steam-driven water supply pumps, and the steam-driven water supply pumps recover to 0 offset from the rotating speed offset at the speed of 2-3 rpm/s, so that the two steam-driven water supply pumps recover to output balance.
The main control instruction of the boiler is less than 500MW, the feed water flow instruction is 1240t/h, and the two steam-driven feed water pumps are positioned near a critical point of a recirculation valve to be opened when running simultaneously.
Compared with the prior art, the invention has the beneficial effects that:
the invention discloses an automatic adjusting method of a steam feed water pump near a critical point of opening a recirculation valve, which comprises the following steps: when the critical point that the recirculation valves of the two steam-driven feed water pumps are opened simultaneously is reached, a rotating speed offset is set for one of the steam-driven feed water pumps, so that the inlet flow of the corresponding steam pump is slowly increased and is far away from the critical point for opening the corresponding recirculation valve, and only the other steam-driven feed water pump is allowed to slowly open the corresponding recirculation valve. The automatic adjusting method of the steam-driven feed water pump near the critical point of the opening recirculation valve provided by the invention can realize that the main feed water flow fluctuation is not too large when the supercritical coal-fired unit is opened near the critical point of the recirculation valve in the unit load change process by opening the single recirculation valve, and is particularly suitable for the supercritical coal-fired unit with two 50% capacity steam-driven feed water pumps configured as the feed water pump.
Drawings
FIG. 1 is a graph of load versus feedwater flow target;
FIG. 2 is a schematic diagram of a bi-fold control strategy for a recirculation valve of a steam feed pump;
FIG. 3 is a double-fold graph of a double-fold control strategy diagram for a recirculation valve of a steam feed pump;
FIG. 4 is a flow chart of the present invention.
Detailed Description
The present invention is described in detail below so that the advantages and features of the present invention can be more easily understood by those skilled in the art, and thus the scope of the present invention can be clearly and clearly defined.
The following presents a simplified summary of one or more aspects in order to provide a basic understanding of such aspects. This summary is not an extensive overview of all contemplated aspects, and is intended to neither identify key or critical elements of all aspects nor delineate the scope of any or all aspects. Its sole purpose is to present some concepts of one or more aspects in a simplified form as a prelude to the more detailed description that is presented later.
As shown in fig. 4, the invention discloses an automatic adjusting method of a steam feed pump near a critical point of an opening recirculation valve, which can realize that the ultra-supercritical coal-fired unit can not cause overlarge fluctuation of main feed water flow when the critical point of the opening recirculation valve is near the load change process of the unit, and is particularly suitable for the ultra-supercritical coal-fired unit with two 50% capacity steam feed pumps configured as the feed pump. The method specifically comprises the following steps:
when a critical point that recirculation valves of two steam-driven water feeding pumps are opened simultaneously is reached, in order to reduce disturbance, a rotating speed offset is set for one of the steam-driven water feeding pumps, so that the inlet flow of the corresponding steam pump is slowly increased at a certain speed and slowly and stably kept away from the critical point for opening the corresponding recirculation valve, under the control of a steam-pump water feeding flow regulating loop, only the other steam-driven water feeding pump is allowed to slowly open the corresponding recirculation valve, the disturbance of the single recirculation valve on the outlet flow of the steam pump is less, and the main water feeding flow cannot cause large main water feeding flow fluctuation because the two recirculation valves are opened simultaneously;
the above-mentioned adjusting method needs to satisfy the following five conditions simultaneously:
1) Both the boiler main control instruction and the unit load instruction are smaller than a critical value;
2) The inlet flow rates of the steam pumps corresponding to the two steam-driven water-feeding pumps are smaller than a certain value and are positioned near a critical point of a recirculation valve to be opened;
3) The recirculation valves corresponding to the two steam feed water pumps are not opened;
4) The rotating speeds of the two steam-driven water feeding pumps are in an automatic control mode;
5) The recirculation valve capable of slowly opening is in an automatic control mode;
it should be particularly pointed out that when the unit load instruction is greater than the critical value, the condition 1) is not satisfied, at this time, the rotating speed offset needs to be recovered to 0 offset at the speed of 2-3 rpm/s, so that the two steam-driven feed water pumps recover the output balance and recover the state before automatic adjustment; wherein the rotating speed offset is 50r/min;
when the load instruction of the unit is larger than the critical value, the target value of the water supply flow is far away from the critical point of the opening of the recirculation valves of the two steam-driven water supply pumps, and the two steam-driven water supply pumps can be restored to the state before automatic adjustment.
The invention can effectively avoid the instability of the main feed water flow when the inlet flow of the steam pump is near the critical point of the opening recirculation valve in the load change process of the unit through the adjusting mode.
It should be noted that, if the rotation speed of any one of the steam-driven feed-water pumps is controlled manually, the condition 4) cannot be met, and thus the rotation speed cannot be adjusted by using the present invention.
Example 1
As shown in fig. 1 and 4, a method for automatically adjusting a steam feed pump near a critical point for opening a recirculation valve, comprising the steps of:
when a critical point that recirculation valves of two steam-driven water-feeding pumps are opened simultaneously is reached, in order to reduce disturbance, a rotating speed offset of 50r/min is set for one of the steam-driven water-feeding pumps (marked as steam-driven water-feeding pump A), so that the inlet flow of the corresponding steam pump (marked as inlet flow of the steam-driven water-feeding pump A) is slowly increased at a certain speed, the critical point is slowly and stably far away from the critical point for opening the recirculation valve (marked as recirculation flow regulating valve of the steam pump A), only the other steam-driven water-feeding pump (marked as steam-driven water-feeding pump B) is slowly opened for the corresponding recirculation valve (marked as recirculation flow regulating valve of the steam pump B) under the control of a steam-pump water-feeding flow regulating loop, a single recirculation valve is opened, the disturbance of the outlet flow of the steam pump is less, and the main water-feeding flow cannot cause large main water-feeding flow fluctuation because the two recirculation valves are simultaneously opened;
the above-mentioned regulation method needs to satisfy the following conditions at the same time:
1) The boiler master control instruction and the unit load instruction are both less than 500MW;
2) The flow rates of the steam pump inlets corresponding to the two steam-driven water-feeding pumps are both less than 660t/h and are positioned near the critical point of the recirculation valve to be opened;
3) The maximum values of the opening degrees of the recirculation valves corresponding to the two steam-driven water-feeding pumps are both less than 3%, and at the moment, the recirculation valves corresponding to the two steam-driven water-feeding pumps are not opened;
4) The rotating speeds of the two steam-driven water feeding pumps are in an automatic control mode;
5) The recirculation valve capable of slowly opening is in an automatic control mode;
when the load instruction of the unit is more than 520MW, the condition 1) is not met, at the moment, the rotating speed offset needs to be recovered to 0 offset at the speed of 2rpm/s, so that the two steam feed water pumps recover the output balance and recover the state before automatic adjustment;
when the load instruction of the unit is ensured to be larger than 520MW, the target value of the water supply flow is far away from the critical point of the opening of the recirculation valves of the two steam-driven water supply pumps, and the two steam-driven water supply pumps can recover the state before automatic adjustment;
through the adjusting mode, the instability of the main feed water flow caused by the inlet flow of the steam pump near the critical point of the opening recirculation valve in the load change process (near 500 MW) of the unit can be effectively avoided.
The main control instruction of the boiler is less than 500MW, the feed water flow instruction is guaranteed to be 1240t/h, and the two steam-driven feed water pumps are positioned near the critical point of the recirculation valve to be opened when running simultaneously.
The parts or structures of the invention which are not described in detail can be the same as those in the prior art or the existing products, and are not described in detail herein.
The above description is only an embodiment of the present invention, and not intended to limit the scope of the present invention, and all modifications of equivalent structures and equivalent processes, which are made by the present specification, or directly or indirectly applied to other related technical fields, are included in the scope of the present invention.
Claims (6)
1. A method for automatically adjusting a steam feed pump near a critical point for opening a recirculation valve, comprising the steps of:
when the critical point that the recirculation valves of the two steam-driven feed water pumps are opened simultaneously is reached, a rotating speed offset is set for one of the steam-driven feed water pumps, so that the inlet flow of the corresponding steam pump is slowly increased and is far away from the critical point for opening the corresponding recirculation valve, and only the other steam-driven feed water pump is allowed to slowly open the corresponding recirculation valve.
2. The method for automatically adjusting the steam-feed water pumps near the critical point of opening the recirculation valves according to claim 1, wherein a rotational speed offset is set for one of the steam-feed water pumps, and only the other steam-feed water pump is required to slowly open the corresponding recirculation valve while satisfying the following conditions:
1) The main control instruction of the boiler and the load instruction of the unit are both smaller than a critical value;
2) The inlet flows of the steam pumps corresponding to the two steam-driven water feeding pumps are both smaller than a certain value and are positioned near a critical point of a recirculation valve to be opened;
3) The recirculation valves corresponding to the two steam feed water pumps are not opened;
4) The rotating speeds of the two steam-driven water feeding pumps are in an automatic control mode;
5) The recirculation valve, which can be slowly opened, is in an automatic control mode.
3. The method for automatically adjusting the steam-feed water pumps near the critical point of opening the recirculation valves according to claim 2, wherein a rotational speed offset is set for one of the steam-feed water pumps, and only the other steam-feed water pump is required to slowly open the corresponding recirculation valve while satisfying the following conditions:
1) Both the boiler master control instruction and the unit load instruction are less than 500MW;
2) The inlet flows of the steam pumps corresponding to the two steam-driven water feeding pumps are both smaller than 660t/h and are positioned near a critical point of a recirculation valve to be opened;
3) The maximum values of the opening degrees of the recirculation valves corresponding to the two steam-driven water-feeding pumps are both less than 3%, and at the moment, the recirculation valves corresponding to the two steam-driven water-feeding pumps are not opened;
4) The rotating speeds of the two steam-driven water feeding pumps are in an automatic control mode;
5) The recirculation valve, which can be slowly opened, is in an automatic control mode.
4. A method of automatically adjusting a steam feed pump near the critical point of opening a recirculation valve according to any of claims 1-3, wherein the rotational speed offset is 50r/min and the ramp rate is 2-3 rpm/s.
5. The method for automatically adjusting the steam feed water pump near the critical point of opening the recirculation valve according to claim 3, wherein when the set load command is greater than 520MW, the feed water flow target value is far away from the critical point of opening the recirculation valves of the two steam feed water pumps, and the steam feed water pumps recover from the rotation speed offset to 0 offset at the speed of 2-3 rpm/s, so that the two steam feed water pumps recover to balance the output.
6. The method of automatically adjusting a steam-feed water pump near a critical point for opening a recirculation valve of claim 2, wherein the boiler master command is less than 500MW, ensuring that a feed water flow command is 1240t/h, and both steam-feed water pumps are operating at the same time near the critical point where the recirculation valve is to be opened.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211565954.8A CN115978526A (en) | 2022-12-07 | 2022-12-07 | Automatic adjusting method of steam feed water pump near critical point of opening recirculation valve |
| PCT/CN2023/131242 WO2024120122A1 (en) | 2022-12-07 | 2023-11-13 | Method for automatically adjusting steam feed pump near critical point at which recirculation valve is opened |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202211565954.8A CN115978526A (en) | 2022-12-07 | 2022-12-07 | Automatic adjusting method of steam feed water pump near critical point of opening recirculation valve |
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| Publication Number | Publication Date |
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| CN115978526A true CN115978526A (en) | 2023-04-18 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202211565954.8A Pending CN115978526A (en) | 2022-12-07 | 2022-12-07 | Automatic adjusting method of steam feed water pump near critical point of opening recirculation valve |
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| WO (1) | WO2024120122A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024120122A1 (en) * | 2022-12-07 | 2024-06-13 | 西安热工研究院有限公司 | Method for automatically adjusting steam feed pump near critical point at which recirculation valve is opened |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP4060654B2 (en) * | 2002-07-12 | 2008-03-12 | 株式会社東芝 | Water supply pump recirculation flow control device |
| CN107355770B (en) * | 2017-06-26 | 2019-04-05 | 华电电力科学研究院 | By steam feed pump to the method for boiler water filling when a kind of Unit Commitment |
| CN108594663B (en) * | 2018-05-22 | 2021-03-23 | 马鞍山当涂发电有限公司 | AGC control method for 660MW supercritical unit under deep peak shaving |
| CN111608928A (en) * | 2020-05-25 | 2020-09-01 | 西安热工研究院有限公司 | Energy-saving optimization method for controlling opening and closing of recirculation valve of steam turbine feed pump |
| CN115978526A (en) * | 2022-12-07 | 2023-04-18 | 西安热工研究院有限公司 | Automatic adjusting method of steam feed water pump near critical point of opening recirculation valve |
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2022
- 2022-12-07 CN CN202211565954.8A patent/CN115978526A/en active Pending
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- 2023-11-13 WO PCT/CN2023/131242 patent/WO2024120122A1/en unknown
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2024120122A1 (en) * | 2022-12-07 | 2024-06-13 | 西安热工研究院有限公司 | Method for automatically adjusting steam feed pump near critical point at which recirculation valve is opened |
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| WO2024120122A1 (en) | 2024-06-13 |
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