CN110986024A - 660MW supercritical unit water supply system steam source switching control device and control method - Google Patents

660MW supercritical unit water supply system steam source switching control device and control method Download PDF

Info

Publication number
CN110986024A
CN110986024A CN201911064374.9A CN201911064374A CN110986024A CN 110986024 A CN110986024 A CN 110986024A CN 201911064374 A CN201911064374 A CN 201911064374A CN 110986024 A CN110986024 A CN 110986024A
Authority
CN
China
Prior art keywords
pipe
steam
water supply
flow
valve
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
CN201911064374.9A
Other languages
Chinese (zh)
Inventor
王孟
方晓敏
赖艳云
钱海龙
王一
王金梁
林晨
章鹏
朱理强
李振
顾洪绪
郑黎明
彭豹先
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
East China Power Test and Research Institute Co Ltd
Original Assignee
East China Power Test and Research Institute Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by East China Power Test and Research Institute Co Ltd filed Critical East China Power Test and Research Institute Co Ltd
Priority to CN201911064374.9A priority Critical patent/CN110986024A/en
Publication of CN110986024A publication Critical patent/CN110986024A/en
Pending legal-status Critical Current

Links

Images

Classifications

    • 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
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01K—STEAM ENGINE PLANTS; STEAM ACCUMULATORS; ENGINE PLANTS NOT OTHERWISE PROVIDED FOR; ENGINES USING SPECIAL WORKING FLUIDS OR CYCLES
    • F01K7/00—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating
    • F01K7/34—Steam engine plants characterised by the use of specific types of engine; Plants or engines characterised by their use of special steam systems, cycles or processes; Control means specially adapted for such systems, cycles or processes; Use of withdrawn or exhaust steam for feed-water heating the engines being of extraction or non-condensing type; Use of steam for feed-water heating
    • 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

Landscapes

  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Thermal Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Control Of Steam Boilers And Waste-Gas Boilers (AREA)
  • Control Of Turbines (AREA)

Abstract

The invention discloses a steam source switching control device and a steam source switching control method for a water supply system of a 660MW supercritical unit. Belonging to the technical field of water supply systems of supercritical units. The steam source switching control of the supercritical unit water supply system is easy to operate when the FCB occurs, and the reliability is good. The system comprises a controller, a boiler, a first pipe, a second pipe, a third pipe, a fourth pipe, a feed pump steam turbine, a T-shaped three-way pipe, an auxiliary steam header and a main steam turbine; a stop valve is arranged on the first pipe; a switching valve is arranged on the second pipe; a main force valve is arranged on the third pipe; a low-pressure regulating valve is arranged on the fourth pipe; the main force valve comprises a steam extraction check valve and an electric valve; the central line of the left end pipe orifice of the three-way pipe and the central line of the right end pipe orifice of the three-way pipe fall on the same horizontal straight line, and the central line of the lower end pipe orifice of the three-way pipe and the central line of the right end pipe orifice of the three-way pipe are mutually vertical.

Description

660MW supercritical unit water supply system steam source switching control device and control method
Technical Field
The invention relates to the technical field of steam source switching control of a water supply system of a supercritical unit, in particular to a steam source switching control device and a steam source switching control method of a water supply system of a 660MW supercritical unit.
Background
When the supercritical unit is used for load shedding, the main power steam source of a feed pump steam turbine of the water supply system is lost, and in order to maintain the normal operation of the water supply system and avoid the great fluctuation of the feed water flow of a boiler, the power steam source needs to be switched into an auxiliary steam source. The pressure and the temperature of the auxiliary steam source are different from those of a conventional power steam source, when the pressure of the auxiliary steam source is too high, the flow of a water supply system fluctuates, and when the pressure of the auxiliary steam source is too low, the flow of water supply is greatly reduced, so that the risk of blowing out can be caused. The opening time of the valve of the auxiliary steam source connected to the power steam source and the duration of each opening degree also influence the supply of the steam source power of the water supply system, thereby influencing the size and stability of the water supply flow of the water supply system. At present, the stability of steam source switching control is poor when the FCB occurs in a water supply system of a supercritical unit.
Disclosure of Invention
The invention provides a 660MW supercritical unit water supply system steam source switching control device and a control method, which are used for solving the defect of poor stability of steam source switching control when an FCB (fiber channel bus) occurs in the conventional supercritical unit water supply system, and are easy to operate and good in reliability.
The technical problem is solved by the following technical scheme:
the 660MW supercritical unit water supply system steam source switching control device comprises a controller, a boiler, a first pipe through which steam flows for debugging, a second pipe through which medium-pressure steam enters, a third pipe through which a main power steam source flows, a fourth pipe through which collected steam flows, a water supply pump steam turbine, a T-shaped three-way pipe, an auxiliary steam header and a main steam turbine;
a stop valve is arranged on the first pipe; a switching valve is arranged on the second pipe; a main force valve is arranged on the third pipe; a low-pressure regulating valve is arranged on the fourth pipe; the main force valve comprises a steam extraction check valve and an electric valve;
the central line of the left end pipe orifice of the three-way pipe and the central line of the right end pipe orifice of the three-way pipe fall on the same horizontal straight line, and the central line of the lower end pipe orifice of the three-way pipe and the central line of the right end pipe orifice of the three-way pipe are mutually vertical;
the pipe orifice at one end of the first pipe is in butt joint with the pipe orifice at the left end of the three-way pipe in a 0-degree horizontal mode, and the pipe orifice at the other end of the first pipe is in butt joint with the auxiliary steam header;
a pipe orifice at one end of the second pipe is communicated and connected with the first pipe between the stop valve and the three-way pipe, and the first pipe is connected with the second pipe at an included angle of 89 degrees; the pipe orifice at the other end of the second pipe is in butt joint connection with a steam outlet of the boiler;
a pipe orifice at one end of the third pipe is in butt joint connection with a pipe orifice at the right end of the three-way pipe in a 0-degree horizontal mode, and a pipe orifice at the other end of the third pipe is in butt joint connection with a steam extraction port of the main steam turbine;
the upper end pipe orifice of the fourth pipe is in butt joint connection with the lower end pipe orifice of the three-way pipe in a 0-degree vertical mode, and the lower end pipe orifice of the fourth pipe is in butt joint connection with the steam inlet of the water feeding pump steam turbine;
the steam extraction check valve is arranged on a third pipe between the three-way pipe and the electric valve;
the lower end pipe orifice of the fourth pipe is in butt joint connection with the steam inlet of the water feeding pump steam turbine;
the other end pipe orifice of the first pipe, the other end pipe orifice of the second pipe and the other end pipe orifice of the third pipe are respectively connected to three steam outlets of the boiler in a butt joint manner;
the first pipe is provided with a flowmeter, the second pipe is also provided with a flowmeter, the third pipe is also provided with a flowmeter, and the fourth pipe is also provided with a flowmeter;
the control end of the water feeding pump turbine, the control end of the stop valve, the control end of the switching valve, the control end of the low-pressure regulating valve, the control end of the steam extraction check valve, the control end of the electric valve and each flowmeter are respectively connected with the controller.
The steam extraction check valve has the function of quick isolation when the steam source of medium-pressure steam inlet is not used. The steam inlet flow is adjusted by adjusting the opening of the low-pressure regulating valve, and the water supply flow is controlled to be matched with the actual working condition.
When the FCB happens, the step opening degree of the switching valve can be calculated through an accurate algorithm, fluctuation of steam flow of the water supply pump steam turbine is reduced to the maximum degree, and meanwhile, after the step opening degree of the switching valve, a steam pressure set value is calculated and matched with the current boiler load, stable steam pressure is provided for the water supply pump steam turbine, and fluctuation of the steam pressure is avoided. And a steam flow set value controlled by the low-pressure regulating valve is calculated, is accurately matched with the current boiler load, and controls the boiler feed water flow to be matched with the boiler load, so that the stability of a feed water system when the FCB occurs is ensured. The steam source switching control method under the FCB working condition is high in safety, good in reliability and simple in structure. The steam source switching control of the supercritical unit water supply system is easy to operate when the FCB occurs, and the reliability is good. The scheme realizes the switching of the main power steam source and the medium-pressure steam inlet steam source by the steam flow balance and auxiliary pressure control, and keeps the stability of the water supply system.
Preferably, the tee is provided at a height of 4 metres above the feed pump turbine. The three-way pipe is separated from the upper surface of the water feeding pump steam turbine by a height of 4 meters, so that the gathered steam flow can form better driving steam flow.
Preferably, the tube axes of the fourth tubes are arranged vertically. The steam flow easily forms vertical decurrent drive steam flow in intraductal, reduces the pipe wall and to blockking of steam flow, and steam flow velocity is effectual.
The control method for the steam source switching control device of the water supply system of the 660MW supercritical unit comprises a step opening degree accurate positioning calculation process of a switching valve, and the calculation process is as follows:
the steam flow balance relationship is a relationship shown in the following formula (1):
Q4= Q1+Q2+Q3（1）
wherein Q4The steam flow (t/h) passing through the fourth pipe is Q1The flow rate (t/h) of steam passing through the first pipe is Q2The steam flow (t/h) passing through the second pipe is Q3The steam flow (t/h) passing through the third pipe;
Q1、Q3the real-time steam flow value can be read by the flow detection meter arranged on the first pipe and the flow detection meter arranged on the third pipe respectively;
Q2the real-time steam flow value and the opening degree kv (%) of the switching valve opening, the steam enthalpy value H (J/kg) before the switching valve on the second pipe, the steam pressure P (mpa) before the switching valve, and the differential pressure △ P before and after the switching valve are calculated according to the switching valve flow rate, and the relationship shown in the following formula (2):
（2）
during the normal operation of the unit, main power steam source on the third pipe supplies steam to maintain the normal test operation of a steam turbine of a water supply pump, and when the working condition of FCB (FASTCUTBACK) is that the unit quickly gets off load to the operation with service power, namely the island operation which we often say) occurs instantaneously, the main power steam source is lost, and according to the formula (1), in order to keep the supply of steam to the unitStabilization of water flow, requiring avoidance of Q at the instant of FCB condition occurrence4Large amplitude fluctuation, so that the switching valve needs to be opened step by step to increase Q2Flow rate, Q2The instantaneous increased flow equals the lost steam flow Q3For maintaining Q4Steam flow is balanced;
at the moment of the FCB working condition, the opening degree kv value of the switching valve is calculated and determined by formula (2), as shown in formula (3):
(3)
the steam pressure P before switching valve is determined by the boiler load L (%) and has a certain linear relation;
when L is less than or equal to 30, P = 0.58;
when 30< L ≦ 40, P =0.58+ (L-30) × 0.006;
when 40< L ≦ 50, P =0.62+ (L-40) × 0.006;
when 50< L ≦ 60, P =0.68+ (L-50) × 0.008;
when 60< L ≦ 70, P =0.76+ (L-60) × 0.011;
when 70< L ≦ 80, P =0.87+ (L-70) × 0.013;
when 80< L ≦ 90, P =1.00+ (L-80) × 0.012;
when 90< L ≦ 95, P =1.12+ (L-90) × 0.022;
when 95< L ≦ 100, P =1.23+ (L-95) × 0.022;
when L > 100, P = 1.23;
after the FCB working condition occurs, the switching valve is opened to the opening degree in a step mode, steam pressure in the fourth pipe corresponding to the boiler load L is automatically maintained through the controller, and the phenomenon that the steam pressure in the fourth pipe fluctuates greatly when the FCB working condition occurs to influence the jump of the water supply flow of the water supply pump steam turbine is avoided.
Preferably, the control method further comprises an automatic control process of the water supply flow, and the control process comprises the following steps:
after the switching valve is opened in a step mode, the steam pressure in the fourth pipe is automatically maintained to be matched with the current boiler load through the controller; meanwhile, the low-pressure regulating valve controls the steam flow entering the water feeding pump turbine to control the rotating speed of the water feeding pump turbine so that the water feeding flow is matched with the load of the boiler;
the set value T of the feed water flow controlled by the low-pressure regulating valve is determined by the load L (%) of the boiler and has a certain linear relation;
when L is less than or equal to 30, T = 600;
when 30< L ≦ 40, T =600+ (L-30) × 15.4;
when 40< L ≦ 50, T =754+ (L-40) × 17.1;
when 50< L ≦ 60, T =925+ (L-50) × 16.0;
when 60< L ≦ 70, T =1085+ (L-60) × 21.8;
when 70< L ≦ 80, T =1303+ (L-70) × 20.2;
when 80< L ≦ 85, T =1505+ (L-80) × 23;
when 85< L ≦ 90, T =1620+ (L-85) × 22;
when 90< L ≦ 100, T =1730+ (L-90) × 22;
when L > 100, T = 1950;
and comparing the set value of the water supply flow with the actual water supply flow, and entering the compared deviation into a PID control module for operation, wherein the operation result acts on the low-pressure regulating valve to control the water supply flow of the water supply pump turbine so as to ensure that the water supply flow of the water supply pump turbine is matched with the load of the boiler.
When the FCB happens, the switching valve is accurately calculated and positioned according to the step opening, and the switching valve is accurately opened to compensate the lost steam quantity caused by the power steam source of the water supply pump steam turbine. And according to the steam inlet pressure of the water feeding pump turbine corresponding to the boiler load, the switching valve is automatically controlled, so that the steam inlet pressure of the water feeding pump turbine is matched with the load. Meanwhile, according to the boiler load, the corresponding feed water flow demand is accurately calculated and used as the set value of the automatic control of the low-pressure regulating valve, the feed water flow is automatically regulated, and the feed water flow is matched with the actual boiler load after the FCB. Through this scheme, water supply control system self-adaptation FCB operating mode has avoided because the unit gets rid of the load feed-water flow and has fluctuated by a wide margin, satisfies FCB operating mode requirement to the security is high, good reliability, simple structure.
The invention can achieve the following effects:
according to the invention, when the FCB occurs, the step opening of the switching valve can be calculated through an accurate algorithm, so that the fluctuation of the steam flow of the water supply pump steam turbine is reduced to the maximum extent, and simultaneously, after the step opening of the switching valve, the steam pressure set value is calculated and matched with the current boiler load, so that stable steam pressure is provided for the water supply pump steam turbine, and the fluctuation of the steam pressure is avoided. And a steam flow set value controlled by the low-pressure regulating valve is calculated, is accurately matched with the current boiler load, and controls the boiler feed water flow to be matched with the boiler load, so that the stability of a feed water system when the FCB occurs is ensured. The steam source switching control method under the FCB working condition is high in safety and good in reliability, and the steam source switching control of the supercritical unit water supply system is easy to operate and good in reliability when the FCB occurs. The safety is good, and the reliability is high.
Drawings
Fig. 1 is a schematic view of a pipe connection structure according to the present invention.
Fig. 2 is a schematic block diagram of a circuit schematic connection structure of the present invention.
Detailed Description
The invention is further described with reference to the following figures and examples.
Example (b): a steam source switching control device of a water supply system of a 660MW supercritical unit is shown in the figures 1-2. The system comprises a controller 17, a boiler 16, a first pipe 7 through which steam flows for debugging, a second pipe 8 through which medium-pressure steam flows, a third pipe 9 through which a main power steam source flows, a fourth pipe 2 through which collected steam flows, a feed pump steam turbine 1, a T-shaped three-way pipe 6, an auxiliary steam header 161 and a main steam turbine 162;
a stop valve 10 is arranged on the first pipe; a switching valve 11 is arranged on the second pipe; a main force valve 21 is arranged on the third pipe; a low-pressure regulating valve 19 is arranged on the fourth pipe; the main force valve comprises a steam extraction check valve 12 and an electric valve 15;
the central line of the left end pipe orifice of the three-way pipe and the central line of the right end pipe orifice of the three-way pipe fall on the same horizontal straight line, and the central line of the lower end pipe orifice of the three-way pipe and the central line of the right end pipe orifice of the three-way pipe are mutually vertical;
the pipe orifice at one end of the first pipe is in butt joint with the pipe orifice 3 at the left end of the three-way pipe in a 0-degree horizontal mode, and the pipe orifice at the other end of the first pipe is in butt joint with the auxiliary steam header;
a pipe orifice at one end of the second pipe is communicated and connected with the first pipe between the stop valve and the three-way pipe, and the first pipe is connected with the second pipe at an included angle of 89 degrees; the pipe orifice at the other end of the second pipe is in butt joint connection with a steam outlet of the boiler;
a pipe orifice at one end of the third pipe is in butt joint with a pipe orifice 4 at the right end of the three-way pipe in a 0-degree horizontal mode, and a pipe orifice at the other end of the third pipe is in butt joint with a steam extraction port of the main steam turbine;
the upper end pipe orifice of the fourth pipe is in butt joint with the lower end pipe orifice 5 of the three-way pipe in a 0-degree vertical mode, and the lower end pipe orifice of the fourth pipe is in butt joint with the steam inlet of the water feeding pump steam turbine;
the steam extraction check valve is arranged on a third pipe between the three-way pipe and the electric valve;
the lower end pipe orifice of the fourth pipe is in butt joint connection with the steam inlet of the water feeding pump steam turbine;
the other end pipe orifice of the first pipe, the other end pipe orifice of the second pipe and the other end pipe orifice of the third pipe are respectively connected to three steam outlets of the boiler in a butt joint manner;
a flowmeter 13 is arranged on the first pipe, a flowmeter 14 is also arranged on the second pipe, a flowmeter 22 is also arranged on the third pipe, and a flowmeter 20 is also arranged on the fourth pipe;
the control end of the water feeding pump turbine, the control end of the stop valve, the control end of the switching valve, the control end of the low-pressure regulating valve, the control end of the steam extraction check valve, the control end of the electric valve and each flowmeter are respectively connected with the controller.
The three-way pipe is arranged at the position of 4 meters above the steam turbine of the feed pump. The pipe core lines of the fourth pipe are vertically arranged.
The control method for the steam source switching control device of the water supply system of the 660MW supercritical unit comprises a step opening degree accurate positioning calculation process of a switching valve, and the calculation process is as follows:
the steam flow balance relationship is a relationship shown in the following formula (1):
Q4= Q1+Q2+Q3（1）
wherein Q4The steam flow (t/h) passing through the fourth pipe is Q1The flow rate (t/h) of steam passing through the first pipe is Q2The steam flow (t/h) passing through the second pipe is Q3The steam flow (t/h) passing through the third pipe;
Q1、Q3the real-time steam flow value can be read by the flow detection meter arranged on the first pipe and the flow detection meter arranged on the third pipe respectively;
Q2the real-time steam flow value and the opening degree kv (%) of the switching valve opening, the steam enthalpy value H (J/kg) before the switching valve on the second pipe, the steam pressure P (mpa) before the switching valve, and the differential pressure △ P before and after the switching valve are calculated according to the switching valve flow rate, and the relationship shown in the following formula (2):
（2）
during the normal operation of the unit, main steam source on the third pipe supplies steam to maintain the normal test operation of a steam turbine of a water feeding pump, the working condition of FCB (FASTCUTBACK) is that the unit quickly gets off load to the operation with service power, namely the island operation which we often say) occurs instantaneously, the main steam source is lost, and according to the formula (1), in order to keep the stability of water feeding flow, Q needs to be avoided at the moment of FCB working condition occurrence4Large amplitude fluctuation, so that the switching valve needs to be opened step by step to increase Q2Flow rate, Q2The instantaneous increased flow equals the lost steam flow Q3For maintaining Q4Steam flow is balanced;
at the moment of the FCB working condition, the opening degree kv value of the switching valve is calculated and determined by formula (2), as shown in formula (3):
(3)
the steam pressure P before switching valve is determined by the boiler load L (%) and has a certain linear relation;
when L is less than or equal to 30, P = 0.58;
when 30< L ≦ 40, P =0.58+ (L-30) × 0.006;
when 40< L ≦ 50, P =0.62+ (L-40) × 0.006;
when 50< L ≦ 60, P =0.68+ (L-50) × 0.008;
when 60< L ≦ 70, P =0.76+ (L-60) × 0.011;
when 70< L ≦ 80, P =0.87+ (L-70) × 0.013;
when 80< L ≦ 90, P =1.00+ (L-80) × 0.012;
when 90< L ≦ 95, P =1.12+ (L-90) × 0.022;
when 95< L ≦ 100, P =1.23+ (L-95) × 0.022;
when L > 100, P = 1.23;
after the FCB working condition occurs, the switching valve is opened to the opening degree in a step mode, steam pressure in the fourth pipe corresponding to the boiler load L is automatically maintained through the controller, and the phenomenon that the steam pressure in the fourth pipe fluctuates greatly when the FCB working condition occurs to influence the jump of the water supply flow of the water supply pump steam turbine is avoided.
The control method also comprises an automatic control process of the water supply flow, and the control process comprises the following steps:
after the switching valve is opened in a step mode, the steam pressure in the fourth pipe is automatically maintained to be matched with the current boiler load through the controller; meanwhile, the low-pressure regulating valve controls the steam flow entering the water feeding pump turbine to control the rotating speed of the water feeding pump turbine so that the water feeding flow is matched with the load of the boiler;
the set value T of the feed water flow controlled by the low-pressure regulating valve is determined by the load L (%) of the boiler and has a certain linear relation;
when L is less than or equal to 30, T = 600;
when 30< L ≦ 40, T =600+ (L-30) × 15.4;
when 40< L ≦ 50, T =754+ (L-40) × 17.1;
when 50< L ≦ 60, T =925+ (L-50) × 16.0;
when 60< L ≦ 70, T =1085+ (L-60) × 21.8;
when 70< L ≦ 80, T =1303+ (L-70) × 20.2;
when 80< L ≦ 85, T =1505+ (L-80) × 23;
when 85< L ≦ 90, T =1620+ (L-85) × 22;
when 90< L ≦ 100, T =1730+ (L-90) × 22;
when L > 100, T = 1950;
and comparing the set value of the water supply flow with the actual water supply flow, and entering the compared deviation into a PID control module for operation, wherein the operation result acts on the low-pressure regulating valve to control the water supply flow of the water supply pump turbine so as to ensure that the water supply flow of the water supply pump turbine is matched with the load of the boiler.
In the embodiment, when the FCB occurs, the step opening of the switching valve is calculated through an accurate algorithm, the fluctuation of the steam flow of the water supply pump steam turbine is reduced to the maximum extent, and meanwhile, after the switching valve is opened in a step mode, a steam pressure set value is calculated and matched with the current boiler load, so that stable steam pressure is provided for the water supply pump steam turbine, and the fluctuation of the steam pressure is avoided. And a steam flow set value controlled by the low-pressure regulating valve is calculated, is accurately matched with the current boiler load, and controls the boiler feed water flow to be matched with the boiler load, so that the stability of a feed water system when the FCB occurs is ensured. The steam source switching control method under the FCB working condition is high in safety, good in reliability and simple in structure. The embodiment realizes the switching of the main force steam source and the medium-pressure steam inlet steam source by the steam flow balance and auxiliary pressure control, and keeps the stability of the water supply system.

Claims (5)

  1. The steam source switching control device of the water supply system of the 1.660MW supercritical unit is characterized by comprising a controller (17), a boiler (16), a first pipe (7) through which steam for debugging flows, a second pipe (8) through which medium-pressure steam enters, a third pipe (9) through which a main power steam source flows, a fourth pipe (2) through which collected steam flows, a water supply pump steam turbine (1), a T-shaped three-way pipe (6), an auxiliary steam header (161) and a main steam turbine (162);
    a stop valve (10) is arranged on the first pipe; a switching valve (11) is arranged on the second pipe; a main force valve (21) is arranged on the third pipe; a low-pressure regulating valve (19) is arranged on the fourth pipe; the main force valve comprises a steam extraction check valve (12) and an electric valve (15);
    the central line of the left end pipe orifice of the three-way pipe and the central line of the right end pipe orifice of the three-way pipe fall on the same horizontal straight line, and the central line of the lower end pipe orifice of the three-way pipe and the central line of the right end pipe orifice of the three-way pipe are mutually vertical;
    the pipe orifice at one end of the first pipe is in butt joint with the pipe orifice (3) at the left end of the three-way pipe in a 0-degree horizontal mode, and the pipe orifice at the other end of the first pipe is in butt joint with the auxiliary steam header;
    a pipe orifice at one end of the second pipe is communicated and connected with the first pipe between the stop valve and the three-way pipe, and the first pipe is connected with the second pipe at an included angle of 89 degrees; the pipe orifice at the other end of the second pipe is in butt joint connection with a steam outlet of the boiler;
    a pipe orifice at one end of the third pipe is in butt joint connection with a pipe orifice (4) at the right end of the three-way pipe in a 0-degree horizontal mode, and a pipe orifice at the other end of the third pipe is in butt joint connection with a steam extraction port of the main steam turbine;
    the upper end pipe orifice of the fourth pipe is in butt joint connection with the lower end pipe orifice (5) of the three-way pipe in a 0-degree vertical mode, and the lower end pipe orifice of the fourth pipe is in butt joint connection with the steam inlet of the water feeding pump steam turbine;
    the steam extraction check valve is arranged on a third pipe between the three-way pipe and the electric valve;
    the lower end pipe orifice of the fourth pipe is in butt joint connection with the steam inlet of the water feeding pump steam turbine;
    the other end pipe orifice of the first pipe, the other end pipe orifice of the second pipe and the other end pipe orifice of the third pipe are respectively connected to three steam outlets of the boiler in a butt joint manner;
    a flowmeter (13) is arranged on the first pipe, a flowmeter (14) is also arranged on the second pipe, a flowmeter (22) is also arranged on the third pipe, and a flowmeter (20) is also arranged on the fourth pipe;
    the control end of the water feeding pump turbine, the control end of the stop valve, the control end of the switching valve, the control end of the low-pressure regulating valve, the control end of the steam extraction check valve, the control end of the electric valve and each flowmeter are respectively connected with the controller.
  2. 2. The steam source switching control device of the 660MW supercritical unit water supply system of claim 1, characterized in that the tee is placed at a height of 4 meters above the water supply pump turbine.
  3. 3. The steam source switching control device of the water supply system of the 660MW supercritical unit as claimed in claim 1, wherein the pipe axes of the four pipes are arranged vertically.
  4. 4. The control method for the steam source switching control device of the water supply system of the 660MW supercritical unit as claimed in claim 1, characterized in that the control method comprises a step opening degree accurate positioning calculation process of the switching valve, and the calculation process is as follows:
    the steam flow balance relationship is a relationship shown in the following formula (1):
    Q4= Q1+Q2+Q3（1）
    wherein Q4The steam flow (t/h) passing through the fourth pipe is Q1The flow rate (t/h) of steam passing through the first pipe is Q2The steam flow (t/h) passing through the second pipe is Q3The steam flow (t/h) passing through the third pipe;
    Q1、Q3the real-time steam flow value can be read by the flow detection meter arranged on the first pipe and the flow detection meter arranged on the third pipe respectively;
    Q2the real-time steam flow value and the opening degree kv (%) of the switching valve opening, the steam enthalpy value H (J/kg) before the switching valve on the second pipe, the steam pressure P (mpa) before the switching valve, and the differential pressure △ P before and after the switching valve are calculated according to the switching valve flow rate, and the relationship shown in the following formula (2):
    （2）
    during the normal operation of the unit, the main steam source on the third pipe supplies steam to maintain the normal test operation of the steam turbine of the water feeding pump, and when the working condition occurs, the main steam source is lost, and according to the formula (1), in order to keep the stability of the water feeding flow, Q needs to be avoided when the FCB working condition occurs4Large amplitude fluctuation, so that the switching valve needs to be opened step by step to increase Q2Flow rate, Q2The instantaneous increased flow equals the lost steam flow Q3For maintaining Q4Steam flow is balanced;
    at the moment of the FCB working condition, the opening degree kv value of the switching valve is calculated and determined by formula (2), as shown in formula (3):
    (3)
    the steam pressure P before switching valve is determined by the boiler load L (%) and has a certain linear relation;
    when L is less than or equal to 30, P = 0.58;
    when 30< L ≦ 40, P =0.58+ (L-30) × 0.006;
    when 40< L ≦ 50, P =0.62+ (L-40) × 0.006;
    when 50< L ≦ 60, P =0.68+ (L-50) × 0.008;
    when 60< L ≦ 70, P =0.76+ (L-60) × 0.011;
    when 70< L ≦ 80, P =0.87+ (L-70) × 0.013;
    when 80< L ≦ 90, P =1.00+ (L-80) × 0.012;
    when 90< L ≦ 95, P =1.12+ (L-90) × 0.022;
    when 95< L ≦ 100, P =1.23+ (L-95) × 0.022;
    when L > 100, P = 1.23;
    after the FCB working condition occurs, the switching valve is opened to the opening degree in a step mode, steam pressure in the fourth pipe corresponding to the boiler load L is automatically maintained through the controller, and the phenomenon that the steam pressure in the fourth pipe fluctuates greatly when the FCB working condition occurs to influence the jump of the water supply flow of the water supply pump steam turbine is avoided.
  5. 5. The control method of the steam source switching control device of the water supply system of the 660MW supercritical unit as claimed in claim 4, wherein the control method further comprises an automatic control process of the water supply flow, and the control process is as follows:
    after the switching valve is opened in a step mode, the steam pressure in the fourth pipe is automatically maintained to be matched with the current boiler load through the controller; meanwhile, the low-pressure regulating valve controls the steam flow entering the water feeding pump turbine to control the rotating speed of the water feeding pump turbine so that the water feeding flow is matched with the load of the boiler;
    the set value T of the feed water flow controlled by the low-pressure regulating valve is determined by the load L (%) of the boiler and has a certain linear relation;
    when L is less than or equal to 30, T = 600;
    when 30< L ≦ 40, T =600+ (L-30) × 15.4;
    when 40< L ≦ 50, T =754+ (L-40) × 17.1;
    when 50< L ≦ 60, T =925+ (L-50) × 16.0;
    when 60< L ≦ 70, T =1085+ (L-60) × 21.8;
    when 70< L ≦ 80, T =1303+ (L-70) × 20.2;
    when 80< L ≦ 85, T =1505+ (L-80) × 23;
    when 85< L ≦ 90, T =1620+ (L-85) × 22;
    when 90< L ≦ 100, T =1730+ (L-90) × 22;
    when L > 100, T = 1950;
    and comparing the set value of the water supply flow with the actual water supply flow, and entering the compared deviation into a PID control module for operation, wherein the operation result acts on the low-pressure regulating valve to control the water supply flow of the water supply pump turbine so as to ensure that the water supply flow of the water supply pump turbine is matched with the load of the boiler.
CN201911064374.9A 2019-11-04 2019-11-04 660MW supercritical unit water supply system steam source switching control device and control method Pending CN110986024A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN201911064374.9A CN110986024A (en) 2019-11-04 2019-11-04 660MW supercritical unit water supply system steam source switching control device and control method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN201911064374.9A CN110986024A (en) 2019-11-04 2019-11-04 660MW supercritical unit water supply system steam source switching control device and control method

Publications (1)

Publication Number Publication Date
CN110986024A true CN110986024A (en) 2020-04-10

Family

ID=70083088

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201911064374.9A Pending CN110986024A (en) 2019-11-04 2019-11-04 660MW supercritical unit water supply system steam source switching control device and control method

Country Status (1)

Country Link
CN (1) CN110986024A (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111878182A (en) * 2020-06-24 2020-11-03 中国能源建设集团华东电力试验研究院有限公司 660MW supercritical unit bypass control system and control method thereof
CN113464213A (en) * 2021-07-23 2021-10-01 中国能源建设集团华中电力试验研究院有限公司 Steam-driven water feed pump control method, module and system for thermal generator set
CN113819400A (en) * 2021-07-30 2021-12-21 西安西热节能技术有限公司 Multi-source integrated automatic switching combined steam supply system and method

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000297608A (en) * 1999-04-14 2000-10-24 Hitachi Ltd Control device for feed water pump of power station
CN102563612A (en) * 2012-01-30 2012-07-11 浙江省电力设计院 Method for directly starting steam-driven feed water pump of large-sized thermal power plant
CN204663593U (en) * 2015-04-20 2015-09-23 浙江汽轮成套技术开发有限公司 The filling control system of Power Plant Feedwater mercury vapour turbine
CN106246261A (en) * 2016-08-31 2016-12-21 中电投宁夏能源铝业中卫热电有限公司 The system of the 350MW supercritical in line Air-Cooling Island of double extraction unit feed pump turbine and method of work thereof
CN206972325U (en) * 2017-07-13 2018-02-06 中国大唐集团科学技术研究院有限公司华东分公司 A kind of small turbine vapour source automatically switches and regulating system
CN109057897A (en) * 2018-06-04 2018-12-21 广东红海湾发电有限公司 Vapour source switching method when for fired power generating unit FCB
CN109296408A (en) * 2018-09-18 2019-02-01 国电南京电力试验研究有限公司 One kind giving mercury vapour turbine vapour source method for handover control

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000297608A (en) * 1999-04-14 2000-10-24 Hitachi Ltd Control device for feed water pump of power station
CN102563612A (en) * 2012-01-30 2012-07-11 浙江省电力设计院 Method for directly starting steam-driven feed water pump of large-sized thermal power plant
CN204663593U (en) * 2015-04-20 2015-09-23 浙江汽轮成套技术开发有限公司 The filling control system of Power Plant Feedwater mercury vapour turbine
CN106246261A (en) * 2016-08-31 2016-12-21 中电投宁夏能源铝业中卫热电有限公司 The system of the 350MW supercritical in line Air-Cooling Island of double extraction unit feed pump turbine and method of work thereof
CN206972325U (en) * 2017-07-13 2018-02-06 中国大唐集团科学技术研究院有限公司华东分公司 A kind of small turbine vapour source automatically switches and regulating system
CN109057897A (en) * 2018-06-04 2018-12-21 广东红海湾发电有限公司 Vapour source switching method when for fired power generating unit FCB
CN109296408A (en) * 2018-09-18 2019-02-01 国电南京电力试验研究有限公司 One kind giving mercury vapour turbine vapour source method for handover control

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111878182A (en) * 2020-06-24 2020-11-03 中国能源建设集团华东电力试验研究院有限公司 660MW supercritical unit bypass control system and control method thereof
CN113464213A (en) * 2021-07-23 2021-10-01 中国能源建设集团华中电力试验研究院有限公司 Steam-driven water feed pump control method, module and system for thermal generator set
CN113819400A (en) * 2021-07-30 2021-12-21 西安西热节能技术有限公司 Multi-source integrated automatic switching combined steam supply system and method

Similar Documents

Publication Publication Date Title
CN110986024A (en) 660MW supercritical unit water supply system steam source switching control device and control method
CN211399756U (en) Steam source switching control device of water supply system of 660MW supercritical unit
CN111878182B (en) 660MW supercritical unit bypass control system and control method thereof
CN110411057A (en) A kind of monitoring method, monitoring device and the air-conditioning system of four-way valve commutation
CN110985137B (en) 660MW supercritical unit water supply system steam flow balance control device and control method
CN204990045U (en) Fluid flow pressure control device
CN109164895A (en) A kind of server liquid cooling system and water pump the using and the reserved no-harass switch control method
CN110510124A (en) A kind of airplane air entraining system
CN102508501B (en) Automatic regulation control system and method for deaerator liquid level of thermal generator set
US7392656B2 (en) Steam turbine plant
CN206488498U (en) A kind of handpiece Water Chilling Units
CN210801231U (en) MGGH white system that disappears with moisturizing steady voltage function
CN211822332U (en) Steam flow balance control device for water supply system of 660MW supercritical unit
CN207196083U (en) Large-scale pressure regulation metering sled
CN113087055B (en) Multi-point vacuumizing system and multi-point vacuumizing method of low-temperature multi-effect sea water desalting device
CN206018925U (en) The cold station control system of central air-conditioning
CN107543141A (en) Steam generator analogue body water supply system and control method during increasing temperature and pressure
CN202383529U (en) Deoxygenator liquid level automatic adjusting and controlling apparatus for thermal power generator set
CN212408800U (en) Heat supply steam connecting pipeline
CN209510665U (en) A kind of turbine vacuum system
CN108591040B (en) Control method, device and the feed-water pump of anti-snatch water in the operation of water supply pumping system
CN217841754U (en) Double-flow low-pressure cylinder water spraying temperature reduction system of steam turbine and steam turbine
CN113161114B (en) Cold rolling welding machine and cooling system of transformer thereof
CN219472354U (en) Cyclone well pumping system capable of reducing failure rate
CN206089057U (en) A central vacuum system for having more platform polycrystalline silicon stove

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
RJ01 Rejection of invention patent application after publication
RJ01 Rejection of invention patent application after publication

Application publication date: 20200410