Method and device for banking fire peak regulation of supercritical circulating fluidized bed boiler

Abstract

The invention provides a method and device for banking-fire peak regulation of a supercritical circulating fluidized bed boiler, and relates to the technical field of boiler banking-fire peak regulation, and the method comprises the steps of banking-fire peak regulation of the supercritical boiler, a banking-fire peak regulation key parameter control method and a banking-fire peak regulation stopping limiting condition. According to the fire banking and peak shaving method and device for the supercritical circulating fluidized bed boiler, the peak shaving capacity of the circulating fluidized bed boiler on a power grid is improved, and absorption of new energy is promoted. Specifically, the invention provides a banking fire peak regulation method, which can reduce the load of a boiler to an extremely low load (3-10MW) in a short time, and is suitable for a banking fire peak regulation technology of a supercritical circulating fluidized bed boiler without boiler water circulating pump transformation.

Description

Technical Field

[0001] The invention relates to the technical field of boiler pressure peak regulation, and in particular to a method and device for pressure peak regulation of a supercritical circulating fluidized bed boiler. Background Art

[0002] New energy is transitioning to the main supplier of incremental electricity in the power system. Coal-fired power is gradually changing from the main power source that traditionally provides electricity and power to a basic and regulating power source that provides auxiliary services such as reliable capacity, peak load regulation and frequency regulation to the power system while providing electricity and power. Peak load regulation of coal-fired power units to solve the problem of new energy consumption is the development trend of new power systems.

[0003] Since circulating fluidized bed boilers have larger heat storage energy, compared with pulverized coal boilers, they can achieve boiler shutdown and hot standby without tripping the turbine and continue to generate electricity. That is, the power load can be reduced to less than 10% of the rated load by suppressing the boiler, thereby achieving peak load regulation.

[0004] The circulating fluidized bed hot standby method of pressure-fire shutdown is an existing common technical method. Its purpose is to put the boiler into hot standby during pressure-fire shutdown when the unit is temporarily stopped, so as to facilitate quick and timely startup. Referring to DL / T 340 "Guidelines for Startup and Commissioning of Circulating Fluidized Bed Boilers", there are preliminary pressure-fire control methods for circulating fluidized beds. However, the current technology is to drive the steam turbine to work when the boiler does not generate steam to achieve peak-shaving power generation for the power grid, and there is a lack of operating methods for peak-shaving power generation during pressure-fire shutdown.

[0005] The invention application with patent application number CN202310739599.X discloses a transformation system for pressure-fire peak regulation of a circulating fluidized bed boiler, including a circulating fluidized bed boiler, a synthesis gas generator, a synthesis gas storage tank, a biomass material dryer and an induced draft fan, wherein the output end of the synthesis gas generator is connected to the input end of the synthesis gas storage tank, the output end of the synthesis gas storage tank is connected to the synthesis gas input end of the circulating fluidized bed boiler, the steam output end of the circulating fluidized bed boiler is connected to the input end of the induced draft fan, the output end of the induced draft fan is respectively connected to the steam input end of the material dryer and the steam input end of the synthesis gas generator, and the output end of the biomass material dryer is connected to the biomass inlet of the synthesis gas generator. On the one hand, the present invention can speed up the speed of load reduction of the unit, prevent accidents such as pipe burst caused by over-temperature and over-pressure of the heating surface on the boiler side, and on the other hand, utilize excess high-temperature steam to dry biomass materials, thereby realizing multi-level utilization of energy.

[0006] However, on the one hand, this method requires equipment modification, and peak load regulation is achieved by adding equipment to establish an energy storage system, which increases the modification cost. On the other hand, this method is suitable for circulating fluidized bed boilers that burn biomass fuels, but not for coal-fired boilers.

[0007] The invention application with patent application number CN201911310539.6 discloses a method for subcritical circulating fluidized bed boilers to adapt to deep peak regulation of power grids. This method can adapt to the peak regulation needs of power grids. During the peak period of renewable energy power generation, the boiler is ignited, the turbine load is reduced to 3-8MW, and the plant power and auxiliary steam are connected by another machine to ensure that the unit can run at low load for 2-3 hours without disconnecting the grid, which just meets the requirements of the power grid's low valley peak regulation period, and can also obtain deep peak regulation compensation to meet the profit requirements of the power plant. The present invention is simple to operate, and can make the unit power consumption systems mutually connected, ensuring that the unit maximizes its benefits during the ignition suppression period, and has certain economy.

[0008] However, this method is only applicable to subcritical boilers and cannot be applied to supercritical boilers. Summary of the invention

[0009] In view of this, the present invention provides a method and device for pressure-controlled peak regulation of a supercritical circulating fluidized bed boiler to solve at least one of the above-mentioned problems.

[0010] In order to achieve the above object, the present invention adopts the following scheme:

[0011] According to a first aspect of the present invention, a method for peak load regulation of a supercritical circulating fluidized bed boiler is provided, wherein the method comprises:

[0012] Step 1: The unit control mode is switched from coordinated to manual control, and the steam turbine is put into manual valve position control;

[0013] Step 2: Shut down all slag coolers;

[0014] Step 3: Open the water bypass;

[0015] Step 4: Close the cooling water branch valve;

[0016] Step 5: Stop all weighing coal feeders and reduce primary and secondary air volumes;

[0017] Step 6: Rapidly reduce the primary fan output to no-load, stop the primary fan and high-pressure fluidizing fan, stop the secondary fan, keep one induced draft fan running for 5 minutes and then stop, close the dampers of all air and smoke systems, and realize the boiler's fire suppression and furnace suffocation;

[0018] Step 7: directly input the valve position opening parameter X1, and adjust the valve position opening parameter X1 according to the pressure drop rate to keep the pressure drop rate less than 0.1 MPa / min;

[0019] Step 8: According to the decrease of extraction steam pressure, gradually stop the air cooling island fan to control the back pressure to be stable;

[0020] Step 9: Adjust the steam supply pressure of the shaft seal to maintain a stable pressure;

[0021] Step 10: According to the rising situation of the exhaust steam temperature of the low-pressure cylinder, inject water into the low-pressure cylinder to control the exhaust steam temperature of the low-pressure cylinder < 65°C;

[0022] Step 11: Manually release the automatic control of the feed water flow rate. After pressing the fire, reduce the water supply to the feed water flow rate X2 to maintain the superheat degree at the intermediate point and the water wall temperature. Adjust the feed water flow rate X2 according to the intermediate point temperature T;

[0023] Step 12: Maintain dry operation and keep the intermediate point temperature at the set value T0. When T < T0, reduce X2; when T > T0, increase X2, and X2 has a lower limit value, not less than 50 t / h;

[0024] Step 13: If the speed of the steam feed pump is lower than 3000 rpm, close the main feed water valve, switch the main feed water path back to the bypass, and control the size of the feed water flow rate X2 with the bypass valve.

[0025] Preferably, in the above method, directly input the valve position opening parameter X1, and adjust the valve position opening parameter X1 according to the pressure drop rate, including: reducing the valve position to the initial value, and the initial value is between 35% and 50%; controlling the valve position opening parameter X1 through the main steam pressure drop rate, power generation load, and main steam temperature drop rate: if the main steam pressure drop rate is higher than 0.3 MPa / min, or the main steam temperature drop rate exceeds 2°C / min, then reduce the valve position opening parameter X1 until the main steam pressure drop rate and the main steam temperature drop rate are qualified; if the power generation load < 3 MW, then increase the valve position opening parameter X1 until the power generation load is greater than or equal to 3 MW, and if the power generation load > 10 MW, then reduce the valve position opening parameter X1 until the power generation load is less than or equal to 10 MW.

[0026] Preferably, in the above method, maintaining the superheat degree at the intermediate point and the water wall temperature, and adjusting the feed water flow rate X2 according to the intermediate point temperature, including: quickly reducing to the preset value after pressing the fire, and the preset value is between 50 t / h and 200 t / h; controlling the feed water flow rate X2 through the steam temperature A1 at the outlet of the water wall, the maximum water wall temperature A2, and the difference A3 between the maximum and minimum values of the water wall: if the rising rate of A1 < 0.5°C / min, then reduce the feed water flow rate X2, and if the values of A2 and A3 exceed the limits of the equipment manufacturer, then increase the feed water flow rate X2.

[0027] Preferably, the above method further includes: when a preset condition occurs during the process of pressing the fire, immediately stop pressing the fire and give an alarm.

[0028] Preferably, the preset conditions in the above method include: ensuring that the superheat and reheat steam temperatures are less than 50°C during the compression period; or the high-exhaust check valve is in a non-open state; or abnormal vibration occurs in each tile of the unit; or the temperature of each tile of the unit rises abnormally; or the boiler water level is out of control and adjustment is ineffective; or the superheat and reheat steam temperatures are out of control or the steam temperature drops by more than 50°C within 10 minutes; or the difference between the superheat and reheat temperatures and the cylinder temperature is greater than 50°C; or the temperature difference between the upper and lower walls of the high-pressure inner cylinder outer wall increases by more than 42°C; or the temperature difference between the upper and lower walls of the high-pressure outer cylinder increases by more than 56°C; or the negative expansion difference of the cylinder is less than the limit value; or the axial displacement increases by more than ±1.0mm; or the turbine exhaust temperature is greater than the limit value; or the water tank liquid level is greater than the limit value, with a delay of more than 30s, and no sign of turning back; or the bed temperature drop rate is greater than 2°C / min; or the maximum bed temperature is greater than 1000°C; or the average bed temperature is less than the limit value; or the steam temperature at the water-cooled wall outlet drops to 0.

[0029] Preferably, the method further includes a pre-fire preparation step before step 1, and the pre-fire preparation step includes:

[0030] Step a: Before ignition, the load is kept stable at 50% for more than half an hour;

[0031] Step b: Complete soot blowing of the entire furnace before ignition;

[0032] Step c: Confirm that there is no internal leakage in the cooling water branch valve;

[0033] Step d: stopping the coal sludge blending device;

[0034] Step e: Notify the maintenance staff to prepare for boiler troubleshooting in advance, notify the thermal control, chemical, coal handling, ash removal and other positions, and require them to cooperate in the boiler fire suppression operation;

[0035] Step f: Test the AC lubricating oil pump, DC lubricating oil pump, jacking oil pump, and turning device of the unit and put them into standby after they start and stop normally;

[0036] Step g: Check and confirm that the auxiliary power quick-cut device is in hot standby state, and the auxiliary power is switched to the standby transformer for operation;

[0037] Step h: The oil guns of the air duct burners of the test boiler are in standby state. Before the test, all the oil guns are tested once to ensure good standby status;

[0038] Step i: Exit the boiler interlock protection, exit the boiler coordinated control, and switch the boiler and steam turbine to manual control;

[0039] Step j: Arrange the auxiliary steam source to supply the adjacent unit, check the three steam sources for the unit shaft seal, including the auxiliary steam source and the cold re-steam source, to make sure that they have been drained and are in hot standby state. According to the unit load and the matching of the shaft seal steam pressure, the temperature of the auxiliary steam source and the metal temperature of the shaft ends on both sides of the high and medium pressure cylinders, select one of the three steam sources to ensure that the shaft seal pressure and the unit vacuum are within the normal range;

[0040] Step k: switching the steam source of the steam pump to the auxiliary steam source;

[0041] Step 1: The high and low pressure bypass systems are fully drained and heated, and are in hot standby state so that they can be put into use in time in case of an accident;

[0042] Step m: Start the electric pump and keep it in standby mode. If the steam pump trips, the electric pump will supply water in time. According to the load reduction situation, the steam pump will be stopped and the electric pump will be kept running to ensure the normal water supply to the boiler.

[0043] Step n: before ignition, gradually stop the steam side operation of the high and low pressure heaters;

[0044] Step o: Check and sort out equipment defects, and do not arrange maintenance during the test unless necessary.

[0045] Preferably, the method further includes a boiler ignition start-up step after step 13, and the boiler ignition start-up step includes:

[0046] Step 14: When the water feed flow rate is 300t / h, start the electric feed pump to restore the boiler;

[0047] Step 15: Adjust the lower secondary air door to 10% and the upper secondary air door to 100%; adjust the coal spreading air damper to 10% to control the amount of cold air entering the bed and slow down the speed of bed temperature drop;

[0048] Step 16: Start the furnace negative pressure automatically, start the fan, start two primary fans to raise the fire, the air volume is 240-270kNm 3 / h; total air volume control 370-400kNm 3 / h to slow down the bed temperature drop and perform hot purge to reset the MFT;

[0049] Step 17: Start the air preheater soot blowing, open the lower plug door of the coal feeder at the same time, start the coal feeder at the same time, and maintain the minimum coal quantity of 40t / h after starting 10 coal feeders; at the same time, start the ignition oil gun under the bed, increase the oil quantity to the maximum output of 5-6t / h, maintain the coal quantity after coal is added, monitor the bed temperature and oxygen content, when the oxygen content decreases and the bed temperature starts to rise, increase the coal supply, and increase the primary and secondary air volume at the same time to reduce the unburned fuel accumulated on the bed and reduce the risk of deflagration;

[0050] Step 18: Feed slag into the slag cooler according to the bed pressure condition.

[0051] According to the second aspect of the present invention, there is provided a device for peak shaving during fire suppression of a supercritical circulating fluidized bed boiler. The device includes: a control switching unit for switching the unit control mode from coordinated control to manual control and putting the steam turbine into manual valve position control; a slag cooler shutdown unit for shutting down all slag coolers; a feed water bypass opening unit for opening the feed water bypass; a desuperheating water branch closing unit for closing the desuperheating water branch valve; a weighing stop and air volume reduction unit for stopping all weighing coal feeders and reducing the primary air volume and secondary air volume; a fire suppression and furnace sealing unit for quickly reducing the output of the primary air fan to no-load, stopping the operation of the primary air fan and the high-pressure fluidizing air fan, stopping the operation of the secondary air fan, keeping one induced draft fan running for 5 minutes and then stopping it, and closing all dampers of the air and flue gas system to achieve fire suppression and furnace sealing of the boiler; a valve position parameter adjustment unit for directly inputting the valve position opening parameter X1 and adjusting the valve position opening parameter X1 according to the pressure drop rate to keep the pressure drop rate less than 0.1 MPa / min; a back pressure control unit for gradually stopping the air-cooled island fans according to the drop of the extraction steam pressure and controlling the back pressure to be stable; a pressure maintenance unit for adjusting the shaft seal steam supply pressure to maintain the pressure stability; an exhaust control unit for injecting water into the low-pressure cylinder according to the rise of the low-pressure cylinder exhaust temperature and controlling the low-pressure cylinder exhaust temperature < 65°C; a feed water flow parameter adjustment unit for automatically releasing the feed water flow from automatic control to manual control, reducing the water supply after fire suppression to the feed water flow X2, maintaining the intermediate point superheat degree and the water wall temperature, and adjusting the feed water flow X2 according to the intermediate point temperature T; an operation maintenance unit for maintaining dry operation and maintaining the intermediate point temperature at the set value T0. When T < T0, reduce X2; when T > T0, increase X2, and X2 has a lower limit value of not less than 50 t / h; a feed water bypass control unit for closing the main feed water valve and switching the main feed water path back to the bypass if the speed of the steam feed pump is lower than 3000 rpm, and controlling the size of the feed water flow X2 with the bypass valve.

[0052] Preferably, the valve position parameter adjustment unit directly inputs the valve position opening parameter X1 and adjusts the valve position opening parameter X1 according to the pressure drop rate, including: reducing the valve position to the initial value, where the initial value is between 35% and 50%; controlling the valve position opening parameter X1 through the main steam pressure drop rate, the power generation load, and the main steam temperature drop rate: if the main steam pressure drop rate is higher than 0.3 MPa / min, or the main steam temperature drop rate exceeds 2°C / min, then reduce the valve position opening parameter X1 until the main steam pressure drop rate and the main steam temperature drop rate are qualified; if the power generation load < 3 MW, then increase the valve position opening parameter X1 until the power generation load is greater than or equal to 3 MW, and if the power generation load > 10 MW, then reduce the valve position opening parameter X1 until the power generation load is less than or equal to 10 MW.

[0053] Preferably, the feed water flow parameter adjustment unit maintains the midpoint superheat and the water-cooled wall temperature, and adjusts the feed water flow X2 according to the midpoint temperature, including: rapidly reducing it to a preset value after ignition, the preset value being between 50t / h and 200t / h; controlling the feed water flow X2 by the water-cooled wall outlet steam temperature A1, the maximum water-cooled wall temperature A2, and the difference A3 between the maximum and minimum water-cooled wall values: if the A1 rising rate is <0.5°C / min, reducing the feed water flow X2; if the A2 and A3 values ​​exceed the equipment manufacturer's limit, increasing the feed water flow X2.

[0054] Preferably, the device further comprises an alarm unit for immediately stopping the fire suppression and giving an alarm when a preset condition occurs during the fire suppression process.

[0055] Preferably, the preset conditions include: ensuring that the superheat and reheat steam temperatures are less than 50°C during the compression period; or the high-exhaust check valve is in a non-open state; or abnormal vibration occurs in each tile of the unit; or the temperature of each tile of the unit rises abnormally; or the boiler water level is out of control and adjustment is ineffective; or the superheat and reheat steam temperatures are out of control or the steam temperature drops by more than 50°C within 10 minutes; or the difference between the superheat and reheat temperatures and the cylinder temperature is greater than 50°C; or the temperature difference between the upper and lower walls of the high-pressure inner cylinder outer wall increases by more than 42°C; or the temperature difference between the upper and lower walls of the high-pressure outer cylinder increases by more than 56°C; or the negative expansion difference of the cylinder is less than the limit value; or the axial displacement increases by more than ±1.0mm; or the turbine exhaust temperature is greater than the limit value; or the water tank liquid level is greater than the limit value, with a delay of more than 30s, and no sign of turning back; or the bed temperature drop rate is greater than 2°C / min; or the maximum bed temperature is greater than 1000°C; or the average bed temperature is less than the limit value; or the steam temperature at the water-cooled wall outlet drops to 0.

[0056] Preferably, the device further comprises a preparation unit for a pre-fire preparation step, wherein the pre-fire preparation step comprises:

[0057] Step a: Before ignition, the load is kept stable at 50% for more than half an hour;

[0058] Step b: Complete soot blowing of the entire furnace before ignition;

[0059] Step c: Confirm that there is no internal leakage in the cooling water branch valve;

[0060] Step d: stopping the coal sludge blending device;

[0061] Step e: Notify the maintenance staff to prepare for boiler troubleshooting in advance, notify the thermal control, chemical, coal handling, ash removal and other positions, and require them to cooperate in the boiler fire suppression operation;

[0062] Step f: Test the AC lubricating oil pump, DC lubricating oil pump, jacking oil pump, and turning device of the unit and put them into standby after they start and stop normally;

[0063] Step g: Check and confirm that the auxiliary power quick-cut device is in hot standby state, and the auxiliary power is switched to the standby transformer for operation;

[0064] Step h: The oil guns of the air duct burners of the test boiler are in standby state. Before the test, all the oil guns are tested once to ensure good standby status;

[0065] Step i: Exit the boiler interlock protection, exit the boiler coordinated control, and switch the boiler and steam turbine to manual control;

[0066] Step j: Arrange the auxiliary steam source to supply the adjacent unit, check the three steam sources for the unit shaft seal, including the auxiliary steam source and the cold re-steam source, to make sure that they have been drained and are in hot standby state. According to the unit load and the matching of the shaft seal steam pressure, the temperature of the auxiliary steam source and the metal temperature of the shaft ends on both sides of the high and medium pressure cylinders, select one of the three steam sources to ensure that the shaft seal pressure and the unit vacuum are within the normal range;

[0067] Step k: switching the steam source of the steam pump to the auxiliary steam source;

[0068] Step 1: The high and low pressure bypass systems are fully drained and heated, and are in hot standby state so that they can be put into use in time in case of an accident;

[0069] Step m: Start the electric pump and keep it in standby mode. If the steam pump trips, the electric pump will supply water in time. According to the load reduction situation, the steam pump will be stopped and the electric pump will be kept running to ensure the normal water supply to the boiler.

[0070] Step n: before ignition, gradually stop the steam side operation of the high and low pressure heaters;

[0071] Step o: Check and sort out equipment defects, and do not arrange maintenance during the test unless necessary.

[0072] Preferably, the device further comprises a fire raising and starting unit, which is used to perform a boiler fire raising and starting step after suppressing the fire, and the boiler fire raising and starting step comprises:

[0073] Step 14: When the water feed flow rate is 300t / h, start the electric feed pump to restore the boiler;

[0074] Step 15: Adjust the lower secondary air door to 10% and the upper secondary air door to 100%; adjust the coal spreading air damper to 10% to control the amount of cold air entering the bed and slow down the speed of bed temperature drop;

[0075] Step 16: Start the furnace negative pressure automatically, start the fan, start two primary fans to raise the fire, the air volume is 240-270kNm 3 / h; total air volume control 370-400kNm 3 / h to slow down the bed temperature drop and perform hot purge to reset the MFT;

[0076] Step 17: Start the air preheater soot blowing, open the lower plug door of the coal feeder at the same time, start the coal feeder at the same time, and maintain the minimum coal quantity of 40t / h after starting 10 coal feeders; at the same time, start the ignition oil gun under the bed, increase the oil quantity to the maximum output of 5-6t / h, maintain the coal quantity after coal is added, monitor the bed temperature and oxygen content, when the oxygen content decreases and the bed temperature starts to rise, increase the coal supply, and increase the primary and secondary air volume at the same time to reduce the unburned fuel accumulated on the bed and reduce the risk of deflagration;

[0077] Step 18: Depending on the bed pressure, start the slag cooler to discharge the slag.

[0078] According to a third aspect of the present invention, there is provided an electronic device, comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, wherein the processor implements the steps of the above method when executing the computer program.

[0079] According to a fourth aspect of the present invention, there is provided a computer-readable storage medium having a computer program stored thereon, wherein the computer program implements the steps of the above method when executed by a processor.

[0080] The method and device for supercritical circulating fluidized bed boiler pressure peak regulation proposed in the present invention improve the peak regulation capacity of the circulating fluidized bed boiler to the power grid and promote the consumption of new energy. Specifically, the present invention provides a method for pressure peak regulation, which can reduce the boiler to an extremely low load (3-10MW) in a short period of time, and is suitable for supercritical circulating fluidized bed boiler pressure peak regulation technology without boiler water circulation pump modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0081] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the prior art descriptions. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work. In the drawings:

[0082] Figure 1 It is a flow chart of a method for pressure-controlled peak regulation of a supercritical circulating fluidized bed boiler provided in an embodiment of the present application;

[0083] Figure 2 It is a schematic flow chart of the pre-fire preparation steps provided by an embodiment of the present invention;

[0084] Figure 3 It is a schematic diagram of a process of starting a boiler after fire suppression provided by an embodiment of the present invention;

[0085] Figure 4It is a structural schematic diagram of a device for pressure-controlled peak regulation of a supercritical circulating fluidized bed boiler provided in an embodiment of the present application;

[0086] Figure 5 It is a structural schematic diagram of an electronic device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0087] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are further described in detail below in conjunction with the accompanying drawings. Here, the exemplary embodiments of the present invention and their descriptions are used to explain the present invention, but are not intended to limit the present invention.

[0088] like Figure 1 The figure shows a flow chart of a method for peak regulation of a supercritical circulating fluidized bed boiler provided in an embodiment of the present application, the method comprising the following steps:

[0089] Step 1: The unit control mode is switched from coordinated control to manual control, and the turbine is put into manual valve position control.

[0090] Step 2: Shut down all slag coolers.

[0091] Step 3: Open the water bypass.

[0092] Step 4: Close the cooling water branch valve.

[0093] Step 5: Stop all weighing coal feeders and reduce primary and secondary air volumes.

[0094] Step 6: Rapidly reduce the primary fan output to no-load, stop the primary fan and high-pressure fluidizing fan, stop the secondary fan, keep one induced draft fan running for 5 minutes before stopping, close all dampers of the air and smoke system to achieve boiler suffocation.

[0095] Step 7: Directly input the valve position opening parameter X1, and adjust the valve position opening parameter X1 according to the pressure drop rate to keep the pressure drop rate less than 0.1 MPa / min.

[0096] Step 8: According to the drop of extraction steam pressure, gradually stop the air cooling island fan and control the back pressure to be stable.

[0097] Step 9: Adjust the steam supply pressure to the shaft seal to maintain a stable pressure.

[0098] Step 10: According to the rising condition of the exhaust temperature of the low-pressure cylinder, start water spraying on the low-pressure cylinder to control the exhaust temperature of the low-pressure cylinder to less than 65℃.

[0099] Step 11: The water supply flow rate is automatically released and manually switched. After the fire is suppressed, the water is reduced to the water supply flow rate X2 to maintain the midpoint superheat and the water-cooled wall temperature. The water supply flow rate X2 is adjusted according to the midpoint temperature T.

[0100] Step 12: Maintain dry operation and keep the intermediate point temperature at the set value T0. When T < T0, decrease X2; when T > T0, increase X2, and X2 has a lower limit value, not less than 50 t / h.

[0101] Step 13: If the speed of the steam pump is lower than 3000 rpm, close the main feed water valve, switch the main feed water path back to the bypass, and control the size of the feed water flow X2 with the bypass valve.

[0102] Preferably, in step 7 of the present application, directly inputting the valve position opening parameter X1 and adjusting the valve position opening parameter X1 according to the pressure drop rate may further include:

[0103] Lower the valve position to the initial value, which is between 35% and 50%. The specific value of the initial value can be adjusted according to tests.

[0104] Control the valve position opening parameter X1 through the main steam pressure drop rate, power generation load, and main steam temperature drop rate: If the main steam pressure drop rate is higher than 0.3 MPa / min, or the main steam temperature drop rate exceeds 2 °C / min, then lower the valve position opening parameter X1 until the main steam pressure drop rate and the main steam temperature drop rate are qualified; if the power generation load < 3 MW, then increase the valve position opening parameter X1 until the power generation load is greater than or equal to 3 MW, and if the power generation load > 10 MW, then lower the valve position opening parameter X1 until the power generation load is less than or equal to 10 MW.

[0105] Preferably, in step 11 of the present application, maintaining the intermediate point superheat degree and the water wall wall temperature and adjusting the feed water flow X2 according to the intermediate point temperature may further include:

[0106] Quickly reduce it to the preset value after pressing the fire, and the preset value is between 50 t / h and 200 t / h. The specific value of the preset value can also be adjusted through tests;

[0107] Control the feed water flow X2 through the steam temperature A1 at the water wall outlet, the maximum value A2 of the water wall wall temperature, and the difference A3 between the maximum and minimum values of the water wall: If the rising rate of A1 < 0.5 °C / min, then reduce the feed water flow X2, and if the values of A2 and A3 exceed the limits of the equipment manufacturer, then increase the feed water flow X2.

[0108] The beneficial effects brought about by the control method of the above-mentioned key parameters X1 and X2 in the present application include: by controlling the comprehensive valve position (X1) and the feed water flow (X2), the operating state of the boiler can be accurately adjusted to ensure that the boiler maintains stable operation during the pressure-fire peak-shaving period. By monitoring and adjusting key parameters, the boiler and related equipment can be prevented from abnormal conditions such as overtemperature and overpressure during the pressure-fire peak-shaving period, thereby avoiding equipment damage. The key parameter control method can quickly respond to the changing needs of the power grid load, adjust the boiler operating state in time, improve the peak-shaving efficiency, and meet the peak-shaving requirements of the power grid. By setting and monitoring the limits of key parameters, abnormal conditions can be discovered and handled in time to ensure the safe operation of the boiler and steam turbine. By accurately controlling the feed water flow and the comprehensive valve position, the energy utilization efficiency of the boiler can also be optimized, energy waste can be reduced, and economical operation can be achieved.

[0109] In summary, the key parameter control method of the present application brings significant beneficial effects by accurately adjusting and monitoring the operating status of the boiler, ensuring the safe, stable and efficient operation of the boiler during the period of pressure-controlled peak regulation.

[0110] Preferably, the above-mentioned fire suppression and peak regulation method of the present application also includes: when a preset condition occurs during the fire suppression process, the fire suppression is immediately stopped and an alarm is issued.

[0111] Further preferably, the preset conditions here include:

[0112] During the compression period, ensure that the superheat and reheat steam temperatures are less than 50℃; or the high-pressure check valve is in the non-open state; or the unit tiles vibrate abnormally; or the temperature of each tile of the unit rises abnormally; or the boiler water level is out of control and the adjustment is ineffective; or the superheat and reheat steam temperatures are out of control or the steam temperature drops by more than 50℃ within 10min; or the difference between the superheat and reheat temperatures and the cylinder temperature is greater than 50℃; or the temperature difference between the upper and lower walls of the high-pressure inner cylinder outer wall increases by more than 42℃; or the temperature difference between the upper and lower walls of the high-pressure outer cylinder increases by more than 56℃; or the negative expansion difference of the cylinder is less than the limit; or the axial displacement increases by more than ±1.0mm; or the turbine exhaust temperature is greater than the limit; or the water tank liquid level is greater than the limit, with a delay of more than 30s, and no sign of turning back; or the bed temperature drop rate is greater than 2℃ / min; or the maximum bed temperature is greater than 1000℃; or the average bed temperature is less than the limit; or the steam temperature at the water-cooled wall outlet drops to 0.

[0113] The above-mentioned steps of stopping the pressure fire and giving an alarm can effectively prevent the boiler and steam turbine equipment from being damaged due to abnormal conditions by setting preset conditions and stopping the pressure fire immediately when the conditions are triggered. For example, overheating, uncontrolled reheat steam temperature or sudden temperature drop may cause excessive thermal stress of the equipment, thereby causing equipment failure. Stopping the pressure fire and giving an alarm in time can avoid safety accidents caused by uncontrolled boiler water level, abnormal vibration of each unit watt or abnormal temperature increase, and ensure the safe operation of the power plant. Maintaining operating parameters within a safe range: By monitoring and controlling key parameters such as superheating, reheat steam temperature, bed temperature, water wall outlet steam temperature, etc., ensure that these parameters operate within a safe range to avoid system instability or loss of control. When the preset conditions are triggered, stopping the pressure fire and giving an alarm immediately can enable the operator to take timely measures, make necessary adjustments and responses, and ensure the stability of the system. By setting detailed preset conditions and control methods, the operating process of boiler pressure fire peak regulation can be optimized and the operating efficiency can be improved.

[0114] In summary, by setting detailed preset conditions and immediately stopping the pressure reduction and issuing an alarm when the conditions are triggered, the safety, stability, equipment life and operating efficiency of the boiler pressure reduction peak regulation process can be significantly improved.

[0115] Preferably, the above step 1 also includes a pre-fire preparation step, such as Figure 2 As shown, the pre-fire preparation steps include:

[0116] Step a: Before ignition, the load is kept stable at 50% for more than half an hour;

[0117] Step b: Complete soot blowing of the entire furnace before ignition;

[0118] Step c: Confirm that there is no internal leakage in the cooling water branch valve;

[0119] Step d: stopping the coal sludge blending device;

[0120] Step e: Notify the maintenance staff to prepare for boiler troubleshooting in advance, notify the thermal control, chemical, coal handling, ash removal and other positions, and require them to cooperate in the boiler fire suppression operation;

[0121] Step f: Test the AC lubricating oil pump, DC lubricating oil pump, jacking oil pump, and turning device of the unit and put them into standby after they start and stop normally;

[0122] Step g: Check and confirm that the auxiliary power quick-cut device is in hot standby state, and the auxiliary power is switched to the standby transformer for operation;

[0123] Step h: The oil guns of the air duct burners of the test boiler are in standby state. Before the test, all the oil guns are tested once to ensure good standby status;

[0124] Step i: Exit the boiler interlock protection, exit the boiler coordinated control, and switch the boiler and steam turbine to manual control;

[0125] Step j: Arrange the auxiliary steam source to supply the adjacent unit, check the three steam sources for the unit shaft seal, including the auxiliary steam source and the cold re-steam source, to make sure that they have been drained and are in hot standby state. According to the unit load and the matching of the shaft seal steam pressure, the temperature of the auxiliary steam source and the metal temperature of the shaft ends on both sides of the high and medium pressure cylinders, select one of the three steam sources to ensure that the shaft seal pressure and the unit vacuum are within the normal range;

[0126] Step k: switching the steam source of the steam pump to the auxiliary steam source;

[0127] Step 1: The high and low pressure bypass systems are fully drained and heated, and are in hot standby state so that they can be put into use in time in case of an accident;

[0128] Step m: Start the electric pump and keep it in standby mode. If the steam pump trips, the electric pump will supply water in time. According to the load reduction situation, the steam pump will be stopped and the electric pump will be kept running to ensure the normal water supply to the boiler.

[0129] Step n: before ignition, gradually stop the steam side operation of the high and low pressure heaters;

[0130] Step o: Check and sort out equipment defects, and do not arrange maintenance during the test unless necessary.

[0131] These preparation steps can ensure the stability and safety of the system, prevent equipment failure, guarantee power supply, optimize control processes, improve emergency response capabilities, ensure stable water supply, reduce energy consumption, and conduct equipment inspection and maintenance, thereby providing solid guarantees for boiler pressure-controlled peak-shaving operations.

[0132] Preferably, the above step 13 further includes a boiler ignition start-up step, such as Figure 3 As shown, the boiler ignition start-up steps include:

[0133] Step 14: When the water feed flow rate is 300t / h, start the electric feed pump to restore the boiler;

[0134] Step 15: Adjust the lower secondary air door to 10% and the upper secondary air door to 100%; adjust the coal spreading air damper to 10% to control the amount of cold air entering the bed and slow down the speed of bed temperature drop;

[0135] Step 16: Start the furnace negative pressure automatically, start the fan, start two primary fans to raise the fire, the air volume is 240-270kNm 3 / h; total air volume control 370-400kNm 3 / h to slow down the bed temperature drop and perform hot purge to reset the MFT;

[0136] Step 17: Start the air preheater soot blowing, open the lower plug door of the coal feeder at the same time, start the coal feeder at the same time, and maintain the minimum coal quantity of 40t / h after starting 10 coal feeders; at the same time, start the ignition oil gun under the bed, increase the oil quantity to the maximum output of 5-6t / h, maintain the coal quantity after coal is added, monitor the bed temperature and oxygen content, when the oxygen content decreases and the bed temperature starts to rise, increase the coal supply, and increase the primary and secondary air volume at the same time to reduce the unburned fuel accumulated on the bed and reduce the risk of deflagration;

[0137] Step 18: Depending on the bed pressure, start the slag cooler to discharge the slag.

[0138] These steps work together to ensure the safety, stability and efficiency of the boiler during the ignition start-up process.

[0139] From the above, it can be seen that the method of supercritical circulating fluidized bed boiler pressure peak regulation proposed in the present invention improves the peak regulation capacity of the circulating fluidized bed boiler to the power grid and promotes the consumption of new energy. Specifically, the present invention provides a method of pressure peak regulation, which can reduce the boiler to an extremely low load (3-10MW) in a short period of time, and is suitable for supercritical circulating fluidized bed boiler pressure peak regulation technology without boiler water circulation pump modification.

[0140] like Figure 4 The figure shows a schematic diagram of the structure of a supercritical circulating fluidized bed boiler pressure peak regulation device provided in an embodiment of the present application, the device comprising: a control switching unit 1, a slag cooler shutdown unit 2, a feed water bypass opening unit 3, a cooling water branch closing unit 4, a weighing stop and air volume reduction unit 5, a pressure furnace suffocating unit 6, a valve position parameter adjustment unit 7, a back pressure control unit 8, a pressure maintaining unit 9, an exhaust control unit 10, a feed water flow parameter adjustment unit 11, an operation maintaining unit 12 and a feed water bypass control unit 13.

[0141] The control switching unit 1 is used to switch the unit control mode from coordinated control to manual control, and the steam turbine is put into manual valve position control.

[0142] The slag cooler shutdown unit 2 is used to shut down all slag coolers.

[0143] The water supply bypass opening unit 3 is used to open the water supply bypass.

[0144] The cooling water branch closing unit 4 is used to close the cooling water branch valve.

[0145] Weighing stop and air volume reduction unit 5: used to stop all weighing coal feeders and reduce primary and secondary air volumes.

[0146] Fire suppression and furnace blanketing unit 6: It is used to quickly reduce the output of the primary air fan to no-load, stop the operation of the primary air fan and the high-pressure fluidized air fan, stop the operation of the secondary air fan, keep one induced draft fan running for another 5 minutes and then stop, and close all dampers of the air and flue gas system to achieve boiler fire suppression and furnace blanketing.

[0147] Valve position parameter adjustment unit 7: It is used to directly input the valve position opening parameter X1, adjust the valve position opening parameter X1 according to the pressure drop rate, and keep the pressure drop rate less than 0.1 MPa / min.

[0148] Back pressure control unit 8: It is used to gradually stop the air-cooled island fans according to the drop of the extraction steam pressure and control the back pressure to be stable.

[0149] Pressure maintenance unit 9: It is used to adjust the shaft seal steam supply pressure and maintain the pressure stability.

[0150] Exhaust control unit 10: It is used to inject low-pressure cylinder spray water according to the rise of the low-pressure cylinder exhaust steam temperature and control the low-pressure cylinder exhaust steam temperature < 65 °C.

[0151] Feed water flow parameter adjustment unit 11: The automatic feed water flow is switched to manual. After fire suppression, the water is reduced to the feed water flow X2, and the intermediate point superheat degree and the water wall temperature are maintained. The feed water flow X2 is adjusted according to the intermediate point temperature.

[0152] Operation maintenance unit 12: Maintain dry operation and maintain the intermediate point temperature at the set value T0. When T < T0, reduce X2; when T > T0, increase X2, and X2 has a lower limit value, not less than 50 t / h.

[0153] Feed water bypass control unit 13: If the speed of the steam feed pump is lower than 3000 rpm, close the main feed water valve, switch the main feed water path back to the bypass, and control the size of the feed water flow X2 with the bypass valve.

[0154] Preferably, the valve position parameter adjustment unit 7 directly inputs the valve position opening parameter X1, and adjusting the valve position opening parameter X1 according to the pressure drop rate includes: reducing the valve position to the initial value, and the initial value is between 35% and 50%; controlling the valve position opening parameter X1 through the main steam pressure drop rate, the power generation load and the main steam temperature drop rate: if the main steam pressure drop rate is higher than 0.3 MPa / min, or the main steam temperature drop rate exceeds 2 °C / min, then reduce the valve position opening parameter X1 until the main steam pressure drop rate and the main steam temperature drop rate are qualified; if the power generation load < 3 MW, then increase the valve position opening parameter X1 until the power generation load is greater than or equal to 3 MW, and if the power generation load > 10 MW, then reduce the valve position opening parameter X1 until the power generation load is less than or equal to 10 MW.

[0155] Preferably, the feed water flow parameter adjustment unit 111 maintains the midpoint superheat and the water-cooled wall temperature, and adjusts the feed water flow X2 according to the midpoint temperature, including: rapidly reducing it to a preset value after ignition, the preset value being between 50t / h and 200t / h; controlling the feed water flow X2 by the water-cooled wall outlet steam temperature A1, the maximum water-cooled wall temperature A2, and the difference A3 between the maximum and minimum water-cooled wall values: if the A1 rising rate is <0.5°C / min, reducing the feed water flow X2; if the A2 and A3 values ​​exceed the equipment manufacturer's limit, increasing the feed water flow X2.

[0156] Preferably, the above-mentioned device also includes an alarm unit, which is used to immediately stop the fire suppression and issue an alarm when a preset condition occurs during the fire suppression process.

[0157] Preferably, the above preset conditions include: ensuring that the superheat and reheat steam temperatures are less than 50°C during the compression period; or the high-exhaust check valve is in a non-open state; or abnormal vibration occurs in each tile of the unit; or the temperature of each tile of the unit rises abnormally; or the boiler water level is out of control and adjustment is ineffective; or the superheat and reheat steam temperatures are out of control or the steam temperature drops by more than 50°C within 10 minutes; or the difference between the superheat and reheat temperatures and the cylinder temperature is greater than 50°C; or the temperature difference between the upper and lower walls of the high-pressure inner cylinder outer wall increases by more than 42°C; or the temperature difference between the upper and lower walls of the high-pressure outer cylinder increases by more than 56°C; or the negative expansion difference of the cylinder is less than the limit value; or the axial displacement increases by more than ±1.0mm; or the turbine exhaust temperature is greater than the limit value; or the water tank liquid level is greater than the limit value, with a delay of more than 30s, and no sign of turning back; or the bed temperature drop rate is greater than 2°C / min; or the maximum bed temperature is greater than 1000°C; or the average bed temperature is less than the limit value; or the steam temperature at the water-cooled wall outlet drops to 0.

[0158] Preferably, the device further comprises a preparation unit for the preparation steps before ignition, and the preparation steps before ignition include:

[0159] Step a: Before ignition, the load is kept stable at 50% for more than half an hour;

[0160] Step b: Complete soot blowing of the entire furnace before ignition;

[0161] Step c: Confirm that there is no internal leakage in the cooling water branch valve;

[0162] Step d: stopping the coal sludge blending device;

[0163] Step e: Notify the maintenance staff to prepare for boiler troubleshooting in advance, notify the thermal control, chemical, coal handling, ash removal and other positions, and require them to cooperate in the boiler fire suppression operation;

[0164] Step f: Test the AC lubricating oil pump, DC lubricating oil pump, jacking oil pump, and turning device of the unit and put them into standby after they start and stop normally;

[0165] Step g: Check and confirm that the auxiliary power quick-cut device is in hot standby state, and the auxiliary power is switched to the standby transformer for operation;

[0166] Step h: The oil guns of the air duct burners of the test boiler are in standby state. Before the test, all the oil guns are tested once to ensure good standby status;

[0167] Step i: Exit the boiler interlock protection, exit the boiler coordinated control, and switch the boiler and steam turbine to manual control;

[0168] Step j: Arrange the auxiliary steam source to supply the adjacent unit, check the three steam sources for the unit shaft seal, including the auxiliary steam source and the cold re-steam source, to make sure that they have been drained and are in hot standby state. According to the unit load and the matching of the shaft seal steam pressure, the temperature of the auxiliary steam source and the metal temperature of the shaft ends on both sides of the high and medium pressure cylinders, select one of the three steam sources to ensure that the shaft seal pressure and the unit vacuum are within the normal range;

[0169] Step k: switching the steam source of the steam pump to the auxiliary steam source;

[0170] Step 1: The high and low pressure bypass systems are fully drained and heated, and are in hot standby state so that they can be put into use in time in case of an accident;

[0171] Step m: Start the electric pump and keep it in standby mode. If the steam pump trips, the electric pump will supply water in time. According to the load reduction situation, the steam pump will be stopped and the electric pump will be kept running to ensure the normal water supply to the boiler.

[0172] Step n: before ignition, gradually stop the steam side operation of the high and low pressure heaters;

[0173] Step o: Check and sort out equipment defects, and do not arrange maintenance during the test unless necessary.

[0174] Preferably, the above device further comprises a fire raising and starting unit, which is used to perform a boiler fire raising and starting step after suppressing the fire, and the boiler fire raising and starting step comprises:

[0175] Step 14: When the water feed flow rate is 300t / h, start the electric feed pump to restore the boiler;

[0176] Step 15: Adjust the lower secondary air door to 10% and the upper secondary air door to 100%; adjust the coal spreading air damper to 10% to control the amount of cold air entering the bed and slow down the speed of bed temperature drop;

[0177] Step 16: Start the furnace negative pressure automatically, start the fan, start two primary fans to raise the fire, the air volume is 240-270kNm 3 / h; total air volume control 370-400kNm 3 / h to slow down the bed temperature drop and perform hot purge to reset the MFT;

[0178] Step 17: Start the air preheater soot blowing, open the lower plug door of the coal feeder at the same time, start the coal feeder at the same time, and maintain the minimum coal quantity of 40t / h after starting 10 coal feeders; at the same time, start the ignition oil gun under the bed, increase the oil quantity to the maximum output of 5-6t / h, maintain the coal quantity after coal is added, monitor the bed temperature and oxygen content, when the oxygen content decreases and the bed temperature starts to rise, increase the coal supply, and increase the primary and secondary air volume at the same time to reduce the unburned fuel accumulated on the bed and reduce the risk of deflagration;

[0179] Step 18: Depending on the bed pressure, start the slag cooler to discharge the slag.

[0180] From the above, it can be seen that the device for supercritical circulating fluidized bed boiler pressure peak regulation proposed by the present invention improves the peak regulation capacity of the circulating fluidized bed boiler to the power grid and promotes the consumption of new energy. Specifically, the present invention provides a method for pressure peak regulation, which can reduce the boiler to an extremely low load (3-10MW) in a short period of time, and is suitable for supercritical circulating fluidized bed boiler pressure peak regulation technology without boiler water circulation pump modification.

[0181] Figure 5 is a schematic diagram of an electronic device provided by an embodiment of the present invention. Figure 5 The electronic device shown is a general data processing device, which includes a general computer hardware structure, which includes at least a processor 801 and a memory 802. The processor 801 and the memory 802 are connected via a bus 803. The memory 802 is suitable for storing one or more instructions or programs executable by the processor 801. The one or more instructions or programs are executed by the processor 801 to implement the steps in the above-mentioned supercritical circulating fluidized bed boiler pressure peak regulation method.

[0182] The processor 801 may be an independent microprocessor or a collection of one or more microprocessors. Thus, the processor 801 executes the commands stored in the memory 802 to execute the method flow of the embodiment of the present invention as described above to realize the processing of data and the control of other devices. The bus 803 connects the above-mentioned multiple components together, and at the same time connects the above-mentioned components to the display controller 804 and the display device and the input / output (I / O) device 805. The input / output (I / O) device 805 may be a mouse, a keyboard, a modem, a network interface, a touch input device, a somatosensory input device, a printer, and other devices known in the art. Typically, the input / output (I / O) device 805 is connected to the system via an input / output (I / O) controller 806.

[0183] The memory 802 may store software components such as an operating system, a communication module, an interaction module, and an application program. Each of the modules and applications described above corresponds to a set of executable program instructions that implement one or more functions and methods described in the embodiments of the invention.

[0184] An embodiment of the present invention further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the above-mentioned supercritical circulating fluidized bed boiler pressure-controlled peak-shaving method.

[0185] From the above, it can be seen that the method and device for supercritical circulating fluidized bed boiler pressure peak regulation proposed in the present invention improves the peak regulation capacity of the circulating fluidized bed boiler to the power grid and promotes the consumption of new energy. Specifically, the present invention provides a method for pressure peak regulation, which can reduce the boiler to an extremely low load (3-10MW) in a short period of time, and is suitable for supercritical circulating fluidized bed boiler pressure peak regulation technology without boiler water circulation pump modification.

[0186] The preferred embodiments of the present invention are described above with reference to the accompanying drawings. Many features and advantages of these embodiments are clear from this detailed description, and therefore the claims are intended to cover all such features and advantages of these embodiments that fall within their true spirit and scope. In addition, since many modifications and changes are easily conceivable to those skilled in the art, it is not intended to limit the embodiments of the present invention to the precise structure and operation illustrated and described, but all suitable modifications and equivalents falling within its scope may be covered.

[0187] Those skilled in the art will appreciate that embodiments of the present invention may be provided as methods, systems, or computer program products. Therefore, the present invention may take the form of a complete hardware embodiment, a complete software embodiment, or an embodiment combining software and hardware. Moreover, the present invention may take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0188] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0189] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0190] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0191] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for peak load regulation of a supercritical circulating fluidized bed boiler, characterized in that: The method includes: Step 1: The unit control mode is switched from coordinated control to manual control, and the steam turbine is put into manual valve position control. Step 2: Stop all slag coolers. Step 3: Open the feed water bypass. Step 4: Close the desuperheating water branch valve. Step 5: Stop all weighing coal feeders, and reduce the primary air flow rate and secondary air flow rate. Step 6: Rapidly reduce the output of the primary air fan to no-load, stop the operation of the primary air fan and high-pressure fluidized bed fan, stop the operation of the secondary air fan, keep one induced draft fan running for another 5 minutes and then stop it, and close all dampers of the air and flue gas system to achieve the boiler's hot standby with the fire suppressed. Step 7: Directly input the valve position opening parameter X1, and adjust the valve position opening parameter X1 according to the pressure drop rate, so as to keep the pressure drop rate less than 0.1 MPa / min. Step 8: Gradually stop the air-cooled island fans according to the drop of the extraction steam pressure, and control the back pressure to be stable. Step 9: Adjust the shaft seal steam supply pressure to maintain the pressure stability. Step 10: According to the rise of the exhaust steam temperature of the low-pressure cylinder, inject water into the low-pressure cylinder to control the exhaust steam temperature of the low-pressure cylinder < 65°C. Step 11: Manually control the feed water flow automatically, and reduce the water supply to the feed water flow X2 after hot standby to maintain the superheat degree at the intermediate point and the water wall temperature, and adjust the feed water flow X2 according to the intermediate point temperature T. Step 12: Maintain dry operation, maintain the intermediate point temperature at the set value T0. When T < T0, reduce X2; when T > T0, increase X2, and X2 has a lower limit value, not less than 50 t / h. Step 13: If the speed of the steam-driven feed pump is lower than 3000 rpm, close the main feed water valve, switch the main feed water path back to the bypass, and control the size of the feed water flow X2 with the bypass valve.

2. The method for peak load regulation of a supercritical circulating fluidized bed boiler according to claim 1, characterized in that: The direct input of the valve position opening parameter X1 and the adjustment of the valve position opening parameter X1 according to the pressure drop rate include: Lower the valve position to the initial value, and the initial value is between 35% and 50%. Control the valve position opening parameter X1 through the main steam pressure drop rate, power generation load and main steam temperature drop rate: If the main steam pressure drop rate is higher than 0.3 MPa / min, or the main steam temperature drop rate exceeds 2°C / min, then reduce the valve position opening parameter X1 until the main steam pressure drop rate and the main steam temperature drop rate are qualified; if the power generation load < 3 MW, then increase the valve position opening parameter X1 until the power generation load is greater than or equal to 3 MW, if the power generation load > 10 MW, then reduce the valve position opening parameter X1 until the power generation load is less than or equal to 10 MW.

3. The method for peak load regulation of a supercritical circulating fluidized bed boiler according to claim 1, characterized in that: The maintenance of the superheat degree at the intermediate point, the water wall temperature, and the adjustment of the feed water flow X2 according to the intermediate point temperature include: Rapidly reduce to the preset value after hot standby, and the preset value is between 50 t / h and 200 t / h. Control the feed water flow X2 through the steam temperature A1 at the outlet of the water wall, the maximum water wall temperature A2, and the difference A3 between the maximum and minimum values of the water wall: If the rising rate of A1 < 0.5°C / min, then reduce the feed water flow X2; if the values of A2 and A3 exceed the limits of the equipment manufacturer, then increase the feed water flow X2.

4. The method for peak load regulation of a supercritical circulating fluidized bed boiler according to claim 1, characterized in that: The method further includes: when a preset condition occurs during the hot standby process, immediately stop the hot standby and give an alarm.

5. The method for peak load regulation of a supercritical circulating fluidized bed boiler according to claim 4, characterized in that: The preset conditions include: During the compression period, ensure that the superheat and reheat steam temperatures are less than 50℃; or the high-pressure check valve is in the non-open state; or the unit tiles vibrate abnormally; or the temperature of each tile of the unit rises abnormally; or the boiler water level is out of control and the adjustment is ineffective; or the superheat and reheat steam temperatures are out of control or the steam temperature drops by more than 50℃ within 10min; or the difference between the superheat and reheat temperatures and the cylinder temperature is greater than 50℃; or the temperature difference between the upper and lower walls of the high-pressure inner cylinder outer wall increases by more than 42℃; or the temperature difference between the upper and lower walls of the high-pressure outer cylinder increases by more than 56℃; or the negative expansion difference of the cylinder is less than the limit; or the axial displacement increases by more than ±1.0mm; or the turbine exhaust temperature is greater than the limit; or the water tank liquid level is greater than the limit, with a delay of more than 30s, and no sign of turning back; or the bed temperature drop rate is greater than 2℃ / min; or the maximum bed temperature is greater than 1000℃; or the average bed temperature is less than the limit; or the steam temperature at the water-cooled wall outlet drops to 0.

6. The method for peak load regulation of a supercritical circulating fluidized bed boiler according to claim 1, characterized in that: The step 1 also includes a pre-fire preparation step, which includes: Step a: Before ignition, the load is kept stable at 50% for more than half an hour; Step b: Complete soot blowing of the entire furnace before ignition; Step c: Confirm that there is no internal leakage in the cooling water branch valve; Step d: stopping the coal sludge blending device; Step e: Notify the maintenance staff to prepare for boiler troubleshooting in advance, notify the thermal control, chemical, coal handling, ash removal and other positions, and require them to cooperate in the boiler fire suppression operation; Step f: Test the AC lubricating oil pump, DC lubricating oil pump, jacking oil pump, and turning device of the unit and put them into standby after they start and stop normally; Step g: Check and confirm that the auxiliary power quick-cut device is in hot standby state, and the auxiliary power is switched to the standby transformer for operation; Step h: The oil guns of the air duct burners of the test boiler are in standby state. Before the test, all the oil guns are tested once to ensure good standby status; Step i: Exit the boiler interlock protection, exit the boiler coordinated control, and switch the boiler and steam turbine to manual control; Step j: Arrange the auxiliary steam source to supply the adjacent unit, check the three steam sources for the unit shaft seal, including the auxiliary steam source and the cold re-steam source, to make sure that they have been drained and are in hot standby state. According to the unit load and the matching of the shaft seal steam pressure, the temperature of the auxiliary steam source and the metal temperature of the shaft ends on both sides of the high and medium pressure cylinders, select one of the three steam sources to ensure that the shaft seal pressure and the unit vacuum are within the normal range; Step k: switching the steam source of the steam pump to the auxiliary steam source; Step 1: The high and low pressure bypass systems are fully drained and heated, and are in hot standby state so that they can be put into use in time in case of an accident; Step m: Start the electric pump and keep it in standby mode. If the steam pump trips, the electric pump will supply water in time. According to the load reduction situation, the steam pump will be stopped and the electric pump will be kept running to ensure the normal water supply to the boiler. Step n: before ignition, gradually stop the steam side operation of the high and low pressure heaters; Step o: Check and sort out equipment defects, and do not arrange maintenance during the test unless necessary.

7. The method for peak load regulation of a supercritical circulating fluidized bed boiler according to claim 1, characterized in that: The step 13 further includes a boiler ignition start-up step, wherein the boiler ignition start-up step includes: Step 14: When the water feed flow rate is 300t / h, start the electric feed pump to restore the boiler; Step 15: Adjust the lower secondary air damper to 10% and the upper secondary air damper to 100%; adjust the coal feeding air damper to 10% to control the cold air volume entering the bed and slow down the bed temperature drop rate; Step 16: Start the furnace negative pressure automatically, start the fan, start two primary fans to raise the fire, the air volume is 240-270kNm 3 / h; total air volume control 370-400kNm 3 / h to slow down the bed temperature drop and perform hot purge to reset the MFT; Step 17: Start the air preheater soot blowing. The operator opens the lower slide gate of the coal feeder and starts the coal feeder. After starting 10 coal feeders, maintain the minimum coal volume of 40 t / h; at the same time, start the ignition oil gun under the bed, increase the oil volume to the maximum output of 5 - 6 t / h, maintain the coal volume after coal feeding, monitor the bed temperature and oxygen content. When the oxygen content decreases and the bed temperature starts to rise, increase the coal feeding volume, and at the same time increase the primary and secondary air volumes to reduce the unburned fuel accumulated in the bed and reduce the risk of deflagration; Step 18: Depending on the bed pressure situation, start the slag cooler to discharge slag.

8. A device for supercritical circulating fluidized bed boiler pressure peak regulation, characterized in that: The device includes: A control switching unit for switching the unit control mode from coordinated control to manual control and putting the steam turbine into manual valve position control; A slag cooler shutdown unit for shutting down all slag coolers; A feed water bypass opening unit for opening the feed water bypass; A desuperheating water branch closing unit for closing the desuperheating water branch valve; A weighing stop and air volume reduction unit: for stopping all weighing coal feeders and reducing the primary air volume and secondary air volume; A fire suppression and furnace sealing unit: for quickly reducing the output of the primary air fan to no-load, stopping the operation of the primary air fan and the high-pressure fluidized air fan, stopping the operation of the secondary air fan, retaining one induced draft fan to continue running for 5 minutes and then stopping, and closing all dampers of the wind and flue gas system to achieve boiler fire suppression and furnace sealing; A valve position parameter adjustment unit for directly inputting the valve position opening parameter X1 and adjusting the valve position opening parameter X1 depending on the pressure drop rate to keep the pressure drop rate less than 0.1 MPa / min; A back pressure control unit: for gradually stopping the air cooling island fans according to the drop of the extraction steam pressure and controlling the back pressure to be stable; A pressure maintenance unit for adjusting the shaft seal steam supply pressure to maintain the pressure stable; An exhaust control unit for injecting low-pressure cylinder spray water according to the rise of the low-pressure cylinder exhaust steam temperature and controlling the low-pressure cylinder exhaust steam temperature < 65°C; A feed water flow parameter adjustment unit: The feed water flow is automatically switched to manual. After fire suppression, reduce the water supply to the feed water flow X2 to maintain the intermediate point superheat degree and the water wall temperature, and adjust the feed water flow X2 depending on the intermediate point temperature T; An operation maintenance unit: Maintain dry operation and maintain the intermediate point temperature at the set value T0. When T < T0, reduce X2; when T > T0, increase X2, and X2 has a lower limit value, not less than 50 t / h; A feed water bypass control unit: If the speed of the steam-driven feed pump is lower than 3000 rpm, close the main feed water valve, switch the main feed water path back to the bypass valve, and control the feed water flow X2 size with the bypass; 9. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the processor executes the computer program, it implements the steps of the method according to any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by the processor, it implements the steps of the method according to any one of claims 1 to 7.

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