CN211822332U - Steam flow balance control device for water supply system of 660MW supercritical unit - Google Patents
Steam flow balance control device for water supply system of 660MW supercritical unit Download PDFInfo
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- CN211822332U CN211822332U CN201921884156.5U CN201921884156U CN211822332U CN 211822332 U CN211822332 U CN 211822332U CN 201921884156 U CN201921884156 U CN 201921884156U CN 211822332 U CN211822332 U CN 211822332U
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Abstract
The utility model discloses a 660MW supercritical unit water supply system steam flow balance control device. Belonging to the technical field of water supply systems of supercritical units. When the FCB occurs, the steam flow balance steam source switching control of the water supply system of the supercritical unit is easy to operate and good in reliability. The system comprises a controller, a boiler, a first pipe, a second pipe, a third pipe, a fourth pipe, a feed pump steam turbine and a T-shaped three-way pipe; 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
Technical Field
The utility model relates to a supercritical unit water supply system technical field, concretely a 660MW supercritical unit water supply system steam flow balance control device.
Background
When the supercritical unit is used for load shedding, the main power steam source of a water feeding pump steam turbine of the water feeding system is lost, and in order to maintain the normal operation of the water feeding system and avoid the great fluctuation of the water feeding flow of a boiler, the power steam flow balance 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, when the FCB occurs, the stability of steam flow balance steam source switching control of a water supply system of a supercritical unit is poor.
SUMMERY OF THE UTILITY MODEL
The utility model relates to a solve the not enough of poor stability of the balanced vapour source switching control of steam flow when FCB takes place of current supercritical unit water supply system, provide an easy operation of the balanced vapour source switching control of steam flow when FCB takes place of supercritical unit water supply system, a 660MW supercritical unit water supply system steam flow balance control device of good reliability.
The technical problem is solved by the following technical scheme:
a660 MW supercritical unit water supply system steam flow balance control device comprises a controller, a boiler, a first pipe for regulating steam flow, a second pipe for medium-pressure steam inflow flow, a third pipe for main steam source flow, a fourth pipe for collecting steam flow, a water supply pump steam turbine, a T-shaped three-way pipe, an auxiliary steam header, a main steam turbine and a steam flow control water inlet mechanism;
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 flow control water inlet mechanism comprises a fifth pipe and a sixth pipe, the outer pipe wall on the right side of the fourth pipe is a vertical plane, and a first side wall hole communicated with the pipe cavity of the fourth pipe is formed in the outer pipe wall on the right side of the fourth pipe; the outer pipe wall on the left side of the fifth pipe is also a vertical plane, a second side wall hole communicated with the pipe cavity of the fifth pipe is formed in the upper end of the outer pipe wall on the left side of the fifth pipe, and a third side wall hole communicated with the pipe cavity of the fifth pipe is formed in the lower end of the outer pipe wall on the right side of the fifth pipe;
the outer pipe wall on the left side of the fifth pipe is integrally and fixedly connected to the outer pipe wall on the right side of the fourth pipe, and a first side wall hole on the fourth pipe is arranged opposite to a second side wall hole on the fifth pipe;
an upper sealed sliding column, an upper lubricating oil column, a middle sealed sliding column, lower lubricating oil and a lower sealed sliding column are sequentially arranged in the cavity of the fifth pipe between the second side wall hole and the third side wall hole from top to bottom; a left transverse plate is fixedly arranged on the upper closed sliding column positioned at the position of the second side wall hole towards the left, and the left end of the left transverse plate extends into the fourth tube; a right transverse plate is fixedly arranged on the lower closed sliding column positioned at the third side wall hole towards the right, and the right end of the right transverse plate extends out of the third side wall hole of the fifth pipe;
a first sealing block is fixedly connected in an upper pipe orifice of the fifth pipe in a sealing manner, a top block is fixedly connected in a lower pipe orifice of the fifth pipe, a spring is arranged in the fifth pipe between the top block and the lower closed sliding column, and two ends of the spring are respectively connected to the top block and the lower closed sliding column in an extruding manner;
the lower end of the outer pipe wall on the left side of the sixth pipe is vertically and fixedly connected with the upper end of the outer pipe wall on the right side of the fifth pipe;
the pipe center line of the fourth pipe, the pipe center line of the fifth pipe and the pipe center line of the sixth pipe are all parallel to the same vertical straight line;
an upper sealing partition plate and a lower sealing partition plate are arranged in the tube cavity of the No. six tube at intervals up and down, so that a sealing cavity is formed in the tube cavity of the No. six tube between the upper sealing partition plate and the lower sealing partition plate;
a lower sealing hole is formed in the middle of the lower sealing partition plate, and a left sealing hole and a right sealing hole are formed in the middle of the upper sealing partition plate side by side at intervals, so that a sealing spacer block is formed on the upper sealing partition plate between the left sealing hole and the right sealing hole;
a water passing notch with an opening at the top end and in a vertical strip shape is formed in the upper end of one vertical plate, so that a left water stop plate and a right water stop plate are formed on two sides of the vertical plate at the position of the water passing notch;
the vertical plate is arranged in the lower sealing hole in a vertically closed sliding mode, the left water-stop plate and the right water-stop plate on the vertical plate are respectively arranged in the left sealing hole and the right sealing hole in a vertically closed sliding mode, the lower end of the vertical plate is fixedly connected to the right transverse plate, and the bottom of the water passing notch is located in the sealing cavity above the lower sealing partition plate when the right transverse plate moves downwards to the bottommost end of the third side wall hole;
when the right transverse plate moves upwards to the upper end of the third side wall hole, the bottom of the water passing notch is hermetically and tightly connected to the sealing spacer block between the left water-stop sheet and the right water-stop sheet, and when the bottom of the water passing notch is hermetically and tightly connected to the sealing spacer block, the sealing cavity is divided into a left cavity and a right cavity which are not communicated by the vertical plate; when the bottom of the water passing notch is not pressed on the sealing spacer block, the sealing cavity is divided into a left cavity and a right cavity which are communicated with each other by the vertical plate;
a fourth side wall hole communicated with the left cavity is formed in the outer wall of the left side of the sixth pipe between the upper sealing partition plate and the lower sealing partition plate, and a fifth side wall hole communicated with the sealing cavity is formed in the outer wall of the right side of the sixth pipe between the upper sealing partition plate and the lower sealing partition plate;
the water outlet of one water supply tank is in butt joint with the side wall hole No. four through a water pipe, and the water inlet of the boiler is in butt joint with the side wall hole No. five through another water pipe.
The water vapor 23 in the fourth tube flows from top to bottom. In the process that water vapor in the fourth tube flows downwards from top to bottom, the water vapor can push the left transverse plate to move downwards, the downward movement distance of the left transverse plate is related to the downward pushing force of the water vapor, the larger the force of the water vapor pushing the left transverse plate downwards, the larger the downward movement distance of the left transverse plate is, the smaller the force of the water vapor pushing the left transverse plate downwards, the smaller the downward movement distance of the left transverse plate is, and the upper surface of the left transverse plate is pressed on the upper end hole wall of the first side wall hole after the force of the water vapor pushing the left transverse plate downwards is smaller to a set minimum value; after the force of the steam pushing the left transverse plate downwards is larger than the set maximum value, the lower surface of the left transverse plate is pressed on the lower end hole wall of the first side wall hole.
The up-and-down movement of the left transverse plate can drive the upper airtight sliding column to move up and down, the up-and-down movement of the upper airtight sliding column can drive the upper lubricating oil column to move up and down, the up-and-down movement of the upper lubricating oil column can drive the middle airtight sliding column to move up and down, the up-and-down movement of the middle airtight sliding column can drive the lower lubricating oil column to move up and down, the up-and-down movement of the lower airtight sliding column can drive the vertical plate to move up and down, the up-and-down movement of the vertical plate can enable the water passing notch to move up and down in the sealing cavity, the water through hole is the area of the opening of the water through gap between the sealing spacer block and the bottom of the water through gap, and the area of the opening of the water through gap in the sealing cavity determines the flow rate of the water 28 entering the right cavity from the left cavity. The water through hole here corresponds to a valve.
The water flow rate of water flowing into the right cavity from the left cavity in unit time can be controlled by the area of the water passing notch in the sealed cavity, namely, the water quantity of water entering the right cavity from the left cavity in unit time is controlled by controlling the left transverse plate to move up and down through water vapor, namely, the water 28 flowing out of the water supply tank can be controlled by controlling the left transverse plate to move up and down through the water vapor to flow into the left cavity of the sealed cavity sequentially through a water pipe, and then the water flows into the boiler from the right cavity through another water pipe after entering the right cavity through the water passing notch on the vertical plate. The reliability is good.
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 flow balance steam source switching control method under the FCB working condition is high in safety, good in reliability and simple in structure. When the FCB occurs, the steam flow balance steam source switching control of the water supply system of the supercritical unit is easy to operate and good in reliability. 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 utility model discloses can reach following effect:
the utility model discloses a when taking place FCB, can open the aperture through accurate algorithm to the diverter valve step and calculate, the fluctuation of maximum reduction feed pump steam turbine steam flow, the back is opened to the step of diverter valve simultaneously, calculates the steam pressure setting value, and with boiler load phase-match at that time, for providing stable steam pressure for the feed pump steam turbine, the fluctuation of steam pressure has been 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 flow balance steam source switching control method under the FCB working condition is high in safety and good in reliability, and the steam flow balance steam source switching control is easy to operate and good in reliability when the FCB occurs in the water supply system of the supercritical unit. The safety is good, and the reliability is high.
Drawings
Fig. 1 is a schematic view of a pipeline connection structure of the present invention.
Fig. 2 is a schematic block diagram of a circuit principle connection structure of the present invention.
Fig. 3 is a schematic view of a connection structure of the steam flow control water inlet mechanism of the present invention, in which the bottom of the water passing notch is not pressed on the sealing spacer.
Fig. 4 is a schematic view of a connection structure of the steam flow control water inlet mechanism of the present invention, in which the bottom of the water passing notch is tightly pressed and connected to the sealing spacer.
Fig. 5 is a schematic view of a connection structure when the left water-stop sheet and the right water-stop sheet on the vertical plate are respectively arranged in the left sealing hole and the right sealing hole in a sliding manner.
Fig. 6 is a schematic view of a connection structure of the left water-stop sheet and the right water-stop sheet on the vertical plate when the left water-stop sheet and the right water-stop sheet are not respectively arranged in the left sealing hole and the right sealing hole in a sealing manner.
Fig. 7 is a schematic view of a connection structure of the present invention in which the outer tube wall on the right side of the fourth tube is a vertical plane.
Detailed Description
The present invention will be further described with reference to the accompanying drawings and examples.
Example (b): a steam flow balance control device for a water supply system of a 660MW supercritical unit is shown in figures 1-7. The system comprises a controller 17, a boiler 16, a first pipe 7 for steam flow for debugging, a second pipe 8 for medium-pressure steam inflow flow, a third pipe 9 for main power steam source flow, a fourth pipe 2 for collecting steam flow, a water feeding pump steam turbine 1, a T-shaped three-way pipe 6, an auxiliary steam header 161, a main steam turbine 162 and a steam flow control water inlet mechanism 18;
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 13 is also arranged on the second pipe, a flowmeter 13 is also arranged on the third pipe, and a flowmeter 13 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 steam flow control water inlet mechanism 18 comprises a fifth pipe 45 and a sixth pipe 29, the outer wall of the right side of the fourth pipe is a vertical plane 56, and a first side wall hole 25 communicated with the pipe cavity of the fourth pipe is arranged on the outer wall of the right side of the fourth pipe; the left outer pipe wall of the fifth pipe is also a vertical plane, a second side wall hole 44 communicated with the pipe cavity of the fifth pipe is formed in the upper end of the left outer pipe wall of the fifth pipe, and a third side wall hole 52 communicated with the pipe cavity of the fifth pipe is formed in the lower end of the right outer pipe wall of the fifth pipe;
the outer pipe wall on the left side of the fifth pipe is integrally and fixedly connected to the outer pipe wall on the right side of the fourth pipe, and a first side wall hole on the fourth pipe is arranged opposite to a second side wall hole on the fifth pipe;
an upper sealed sliding column 46, an upper lubricating oil column 47, a middle sealed sliding column 48, lower lubricating oil 49 and a lower sealed sliding column 50 are sequentially arranged in the cavity of the fifth pipe between the second side wall hole and the third side wall hole from top to bottom; a left transverse plate 24 is fixedly arranged on the upper closed sliding column positioned at the position of the second side wall hole towards the left, and the left end of the left transverse plate extends into the fourth tube; a right transverse plate 51 is fixedly arranged on the lower closed sliding column positioned at the third side wall hole towards the right, and the right end of the right transverse plate extends out of the third side wall hole of the fifth pipe;
a first sealing block 43 is fixedly connected in an upper pipe orifice of the fifth pipe in a sealing manner, a top block 55 is fixedly connected in a lower pipe orifice of the fifth pipe, a spring 54 is arranged in the fifth pipe between the top block and the lower closed sliding column, and two ends of the spring are respectively connected to the top block and the lower closed sliding column in an extruding manner;
the lower end of the outer pipe wall on the left side of the sixth pipe is vertically and fixedly connected with the upper end of the outer pipe wall on the right side of the fifth pipe;
the pipe center line of the fourth pipe, the pipe center line of the fifth pipe and the pipe center line of the sixth pipe are all parallel to the same vertical straight line;
an upper sealing partition plate 30 and a lower sealing partition plate 40 are arranged in the tube cavity of the sixth tube at intervals up and down, so that a sealing cavity 36 is formed in the tube cavity of the sixth tube between the upper sealing partition plate and the lower sealing partition plate;
a lower sealing hole 41 is formed in the middle of the lower sealing partition plate, and a left sealing hole 57 and a right sealing hole 58 are formed in the middle of the upper sealing partition plate side by side at intervals, so that a sealing spacer block 31 is formed on the upper sealing partition plate between the left sealing hole and the right sealing hole;
a water passing notch 59 with an opening top end and in a vertical strip shape is formed in the upper end of one vertical plate 42, so that a left water stop plate 32 and a right water stop plate 38 are formed on two sides of the vertical plate at the position of the water passing notch;
the vertical plate is arranged in the lower sealing hole in a vertically closed sliding mode, the left water-stop plate and the right water-stop plate on the vertical plate are respectively arranged in the left sealing hole and the right sealing hole in a vertically closed sliding mode, the lower end of the vertical plate is fixedly connected to the right transverse plate, and the bottom of the water passing notch is located in a sealing cavity above the lower sealing partition plate when the right transverse plate moves downwards to the bottommost end 53 of the third side wall hole;
when the right transverse plate moves upwards to the upper end of the third side wall hole, the bottom of the water passing notch is hermetically and tightly connected to the sealing spacer block between the left water-stop sheet and the right water-stop sheet, and when the bottom of the water passing notch is hermetically and tightly connected to the sealing spacer block, the sealing cavity is divided into a left cavity and a right cavity which are not communicated by the vertical plate; when the bottom of the water passing notch is not pressed on the sealing spacer block, the sealing cavity is divided into a left cavity 34 and a right cavity 35 which are communicated with each other by the vertical plate;
a fourth side wall hole 39 communicated with the left cavity is formed in the outer wall of the left side of the sixth pipe between the upper sealing partition plate and the lower sealing partition plate, and a fifth side wall hole 37 communicated with the sealing cavity is formed in the outer wall of the right side of the sixth pipe between the upper sealing partition plate and the lower sealing partition plate;
the water outlet of a water supply tank 27 is connected to the fourth side wall hole in a butt joint mode through a water pipe 26, and the water inlet of the boiler 16 is connected to the fifth side wall hole in a butt joint mode through another water pipe 33.
The water vapor 23 in the fourth tube flows from top to bottom. In the process that water vapor in the fourth tube flows downwards from top to bottom, the water vapor can push the left transverse plate to move downwards, the downward movement distance of the left transverse plate is related to the downward pushing force of the water vapor, the larger the force of the water vapor pushing the left transverse plate downwards, the larger the downward movement distance of the left transverse plate is, the smaller the force of the water vapor pushing the left transverse plate downwards, the smaller the downward movement distance of the left transverse plate is, and the upper surface of the left transverse plate is pressed on the upper end hole wall of the first side wall hole after the force of the water vapor pushing the left transverse plate downwards is smaller to a set minimum value; after the force of the steam pushing the left transverse plate downwards is larger than the set maximum value, the lower surface of the left transverse plate is pressed on the lower end hole wall of the first side wall hole.
The up-and-down movement of the left transverse plate can drive the upper airtight sliding column to move up and down, the up-and-down movement of the upper airtight sliding column can drive the upper lubricating oil column to move up and down, the up-and-down movement of the upper lubricating oil column can drive the middle airtight sliding column to move up and down, the up-and-down movement of the middle airtight sliding column can drive the lower lubricating oil column to move up and down, the up-and-down movement of the lower airtight sliding column can drive the vertical plate to move up and down, the up-and-down movement of the vertical plate can enable the water passing notch to move up and down in the sealing cavity, the water through hole is the area of the opening of the water through gap between the sealing spacer block and the bottom of the water through gap, and the area of the opening of the water through gap in the sealing cavity determines the flow rate of the water 28 entering the right cavity from the left cavity. The water through hole here corresponds to a valve.
The water flow rate of water flowing into the right cavity from the left cavity in unit time can be controlled by the area of the water passing notch in the sealed cavity, namely, the water quantity of water entering the right cavity from the left cavity in unit time is controlled by controlling the left transverse plate to move up and down through water vapor, namely, the water 28 flowing out of the water supply tank can be controlled by controlling the left transverse plate to move up and down through the water vapor to flow into the left cavity of the sealed cavity sequentially through a water pipe, and then the water flows into the boiler from the right cavity through another water pipe after entering the right cavity through the water passing notch on the vertical plate. The reliability is good.
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 flow balance 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 Δ P before and after the switching valve, the following formula (2) is calculated according to the switching valve flow:
Q2＝kv×ΔP×P×[304×(0.028×H-17.7)](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):
kv＝Q2÷{ΔP×P×[304×(0.028×H-17.7)]} (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 is 0.58;
when L is more than 30 and less than or equal to 40, P is 0.58+ (L-30) × 0.006;
when L is more than 40 and less than or equal to 50, P is 0.62+ (L-40) × 0.006;
when L is more than 50 and less than or equal to 60, P is 0.68+ (L-50) × 0.008;
when L is more than 60 and less than or equal to 70, P is 0.76+ (L-60) × 0.011;
when L is more than 70 and less than or equal to 80, P is 0.87+ (L-70) 0.013;
when L is more than 80 and less than or equal to 90, P is 1.00+ (L-80) × 0.012;
when L is more than 90 and less than or equal to 95, P is 1.12+ (L-90) 0.022;
when L is more than 95 and less than or equal to 100, P is 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 is 600;
when L is more than 30 and less than or equal to 40, T is 600+ (L-30) × 15.4;
when L is more than 40 and less than or equal to 50, T is 754+ (L-40) × 17.1;
when L is more than 50 and less than or equal to 60, T is 925+ (L-50) 16.0;
when L is more than 60 and less than or equal to 70, T is 1085+ (L-60) × 21.8;
when L is more than 70 and less than or equal to 80, T is 1303+ (L-70) × 20.2;
when L is more than 80 and less than or equal to 85, T is 1505+ (L-80) × 23;
when L is more than 85 and less than or equal to 90, T is 1620+ (L-85) × 22;
when L is more than 90 and less than or equal to 100, T is 1730+ (L-90) × 22;
when L > 100, T1950;
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 flow balance 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 (1)
1. A660 MW supercritical unit water supply system steam flow balance control device is characterized by comprising a controller (17), a boiler (16), a first pipe (7) for debugging steam to flow through, a second pipe (8) for middle-pressure steam inlet to flow through, a third pipe (9) for main force steam source to flow through, a fourth pipe (2) for collecting steam to flow through, a water supply pump steam turbine (1), a T-shaped three-way pipe (6), an auxiliary steam header (161), a main steam turbine (162) and a steam flow control water inlet mechanism;
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;
a flowmeter (13) is arranged on the first pipe, a flowmeter (13) is also arranged on the second pipe, a flowmeter (13) is also arranged on the third pipe, and a flowmeter (13) 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 steam flow control water inlet mechanism comprises a fifth pipe and a sixth pipe, the outer pipe wall on the right side of the fourth pipe is a vertical plane, and a first side wall hole communicated with the pipe cavity of the fourth pipe is formed in the outer pipe wall on the right side of the fourth pipe; the outer pipe wall on the left side of the fifth pipe is also a vertical plane, a second side wall hole communicated with the pipe cavity of the fifth pipe is formed in the upper end of the outer pipe wall on the left side of the fifth pipe, and a third side wall hole communicated with the pipe cavity of the fifth pipe is formed in the lower end of the outer pipe wall on the right side of the fifth pipe;
the outer pipe wall on the left side of the fifth pipe is integrally and fixedly connected to the outer pipe wall on the right side of the fourth pipe, and a first side wall hole on the fourth pipe is arranged opposite to a second side wall hole on the fifth pipe;
an upper sealed sliding column, an upper lubricating oil column, a middle sealed sliding column, lower lubricating oil and a lower sealed sliding column are sequentially arranged in the cavity of the fifth pipe between the second side wall hole and the third side wall hole from top to bottom; a left transverse plate is fixedly arranged on the upper closed sliding column positioned at the position of the second side wall hole towards the left, and the left end of the left transverse plate extends into the fourth tube; a right transverse plate is fixedly arranged on the lower closed sliding column positioned at the third side wall hole towards the right, and the right end of the right transverse plate extends out of the third side wall hole of the fifth pipe;
a first sealing block is fixedly connected in an upper pipe orifice of the fifth pipe in a sealing manner, a top block is fixedly connected in a lower pipe orifice of the fifth pipe, a spring is arranged in the fifth pipe between the top block and the lower closed sliding column, and two ends of the spring are respectively connected to the top block and the lower closed sliding column in an extruding manner;
the lower end of the outer pipe wall on the left side of the sixth pipe is vertically and fixedly connected with the upper end of the outer pipe wall on the right side of the fifth pipe;
the pipe center line of the fourth pipe, the pipe center line of the fifth pipe and the pipe center line of the sixth pipe are all parallel to the same vertical straight line;
an upper sealing partition plate and a lower sealing partition plate are arranged in the tube cavity of the No. six tube at intervals up and down, so that a sealing cavity is formed in the tube cavity of the No. six tube between the upper sealing partition plate and the lower sealing partition plate;
a lower sealing hole is formed in the middle of the lower sealing partition plate, and a left sealing hole and a right sealing hole are formed in the middle of the upper sealing partition plate side by side at intervals, so that a sealing spacer block is formed on the upper sealing partition plate between the left sealing hole and the right sealing hole;
a water passing notch with an opening at the top end and in a vertical strip shape is formed in the upper end of one vertical plate, so that a left water stop plate and a right water stop plate are formed on two sides of the vertical plate at the position of the water passing notch;
the vertical plate is arranged in the lower sealing hole in a vertically closed sliding mode, the left water-stop plate and the right water-stop plate on the vertical plate are respectively arranged in the left sealing hole and the right sealing hole in a vertically closed sliding mode, the lower end of the vertical plate is fixedly connected to the right transverse plate, and the bottom of the water passing notch is located in the sealing cavity above the lower sealing partition plate when the right transverse plate moves downwards to the bottommost end of the third side wall hole;
when the right transverse plate moves upwards to the upper end of the third side wall hole, the bottom of the water passing notch is hermetically and tightly connected to the sealing spacer block between the left water-stop sheet and the right water-stop sheet, and when the bottom of the water passing notch is hermetically and tightly connected to the sealing spacer block, the sealing cavity is divided into a left cavity and a right cavity which are not communicated by the vertical plate; when the bottom of the water passing notch is not pressed on the sealing spacer block, the sealing cavity is divided into a left cavity and a right cavity which are communicated with each other by the vertical plate;
a fourth side wall hole communicated with the left cavity is formed in the outer wall of the left side of the sixth pipe between the upper sealing partition plate and the lower sealing partition plate, and a fifth side wall hole communicated with the sealing cavity is formed in the outer wall of the right side of the sixth pipe between the upper sealing partition plate and the lower sealing partition plate;
the water outlet of one water supply tank is in butt joint with the side wall hole No. four through a water pipe, and the water inlet of the boiler is in butt joint with the side wall hole No. five through another water pipe.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921884156.5U CN211822332U (en) | 2019-11-04 | 2019-11-04 | Steam flow balance control device for water supply system of 660MW supercritical unit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201921884156.5U CN211822332U (en) | 2019-11-04 | 2019-11-04 | Steam flow balance control device for water supply system of 660MW supercritical unit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN211822332U true CN211822332U (en) | 2020-10-30 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201921884156.5U Active CN211822332U (en) | 2019-11-04 | 2019-11-04 | Steam flow balance control device for water supply system of 660MW supercritical unit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN211822332U (en) |
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2019
- 2019-11-04 CN CN201921884156.5U patent/CN211822332U/en active Active
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