One-key drainage control method for high-pressure main steam system of gas-steam combined cycle unit

Abstract

The invention discloses a one-key drain control method for a high-pressure main steam system of a gas-steam combined cycle unit, belongs to a drain control technology of the gas-steam combined cycle unit, and aims to solve the problem that automatic drain control of the existing unit is mainly realized by linkage protection logic based on a single drain valve. For different states of the unit in the starting process, a sequence control method in which all the drain valves are mutually correlated is combined with drain valve linkage protection, and under the condition that normal boosting and pipe warming speed are not affected, the drain valve linkage protection is combined with the drain valve linkage protection, the drain valve linkage protection is not influenced, so that the drain valve linkage protection can be realized, and the drain valve linkage protection can be realized. One-button type automatic drainage of the high-pressure main steam system of the unit is achieved, water impact and working medium waste at key components such as pipelines, valves and turbine blades are reduced, and safety, reliability and economical efficiency of system operation are improved. The requirement that the automatic drainage requirement of a unit in a cold state and a hot state cannot be considered due to the fact that the working condition of a thermodynamic system cannot meet the automatic switch condition of the drainage valve under interlocking protection logic is met.

Description

Technical Field

[0001] The invention belongs to a gas-steam combined cycle unit drain control technology, and in particular relates to a one-button drain control method for a high-pressure main steam system of a gas-steam combined cycle unit. Background Art

[0002] With the proposal of the "dual carbon" goal and the rise of photovoltaic power generation, the difference between the day and night load and supply of the power grid is increasing. In order to meet the needs of the power grid to reduce peak loads and fill valleys, the gas turbines in thermal power plants need to give full play to their advantages of rapid start and stop to adjust the power plant output in time, so as to achieve the overall energy supply of the power system and reduce power abandonment. At present, the gas-steam combined cycle units used in the production site mostly adopt a two-shift system of daytime operation and nighttime shutdown to achieve peak load regulation. This frequent start and stop means that the unit is usually in a hot state rather than a cold state when it is restarted. The large amount of high-temperature and high-pressure steam still existing in its thermal system puts higher requirements on the unit's drain control. In addition, the traditional manual control of start and stop drain operation is large, and it is difficult to accurately control the time nodes of each operation, and there is a risk of misoperation, which limits the safety, reliability and economy of the unit. To this end, it is necessary to add automatic drain control when the unit is started and stopped to improve the automation level of the unit.

[0003] Traditional automatic drain control of units is mainly implemented by interlocking protection logic based on a single drain valve. This independent valve control method can only cope with the drain control during cold start-up of the unit and cannot meet the drain demand during hot start-up. Summary of the invention

[0004] In order to make up for the deficiencies of the above-mentioned prior art, the present invention proposes a one-button drain control method for the high-pressure main steam system of a gas-steam combined cycle unit to address the problem of draining the high-pressure main steam system when the unit is started in cold and hot states.

[0005] To achieve the above object, the one-key drain control method for the high-pressure main steam system of a gas-steam combined cycle unit of the present invention is characterized by:

[0006] The unit includes a #1 high-pressure superheater, a #2 high-pressure superheater, a #3 high-pressure superheater, a high-level first-stage desuperheater, a high-level second-stage desuperheater, a #1 high-pressure superheater #2 trap, a #1 high-pressure superheater #3 trap, a #2 high-pressure superheater trap, a #3 high-pressure superheater trap, a high-level first-stage desuperheater outlet trap, a high-level second-stage desuperheater outlet trap, and a high-pressure main steam electric valve, a high-pressure main steam electric valve front trap, a high-pressure main steam electric valve rear trap, a high-pressure main steam valve front drain primary valve, and a high-pressure main steam valve front drain secondary valve on the machine side;

[0007] The boiler side drain and the machine side drain are executed independently;

[0008] When executing boiler side draining: determine whether the unit is in cold or hot state; when the unit is in cold state, start automatic draining according to the sub-group sequence control program of boiler side cold state start; when the unit is in hot state, start automatic draining according to the sub-group sequence control program of boiler side hot state start;

[0009] When executing machine side drain: determine whether the unit is in cold or hot state; when the unit is in cold state, start automatic drain according to the sub-group sequence control program of machine side cold state start; when the unit is in hot state, start automatic drain according to the sub-group sequence control program of machine side hot state start.

[0010] The present invention replaces the traditional independent interlocking protection logic of steam traps based on the working conditions of the thermal system with a sequential control method in which there is a specific logical relationship between the status and operation of each steam trap, and provides respective sequential control strategies for automatic steam trapping when the unit is started in cold and hot states to reduce water shock and waste of working fluid.

[0011] Preferably, when performing furnace-side draining, the startup is terminated on the condition that the sub-loop interlocking protection control programs of the high-pressure superheater and the high-pressure system pipeline have been put into operation; when performing machine-side draining, the startup is terminated on the condition that the electric valve from the high-pressure main steam to the medium-pressure heating pipe has been closed.

[0012] Among them, the sub-loop interlocking protection control program is that each steam trap is automatically opened based on at least one condition: one is that the liquid level of the steam trap collector of the unit's thermal system rises to a high level, and the other is that the superheat of the unit's thermal system is lower than a certain threshold; otherwise it is closed.

[0013] Preferably, when performing furnace-side draining and machine-side draining, the unit is judged to be in a cold state based on the activation of the cold start signal or the high-pressure main steam pressure being less than 0.75 MPa, otherwise it is judged to be in a hot state.

[0014] Preferably, (1) the switch condition of the steam trap of the high-pressure main steam system on the furnace side is:

[0015] Automatic opening: The sub-circuit interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation, the corresponding temperature superheat of the pipeline where the steam trap is located is lower than 13.9℃, or the step opening instruction in the sub-group sequence control program of the boiler side high-pressure main steam system drain is started.

[0016] Automatic closing: the sub-circuit interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation, the corresponding temperature superheat of the pipeline where the steam trap is located is greater than 27.8℃, or the step closing instruction in the sub-group sequence control program of the boiler side high-pressure main steam system drain is started;

[0017] (2) The switch conditions of the steam trap of the high-pressure main steam system on the machine side are:

[0018] Automatic opening: The sub-circuit interlock protection control program of the high-pressure main steam system pipeline drain is put into operation and the liquid level of the corresponding drain collector of the pipeline where the drain valve is located rises to a high level, or the step opening instruction in the sub-group sequence control program of the high-pressure main steam system drain on the starter side is started.

[0019] Automatic closing: The sub-loop interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation and the liquid level of the corresponding drain collector of the pipeline where the drain valve is located drops to a low level, or the step closing instruction in the sub-group sequential control program of the high-pressure main steam system drain on the starter side is initiated.

[0020] The subgroup sequential control program for cold start of the furnace side is:

[0021] LC01: Open all steam traps on the furnace side, that is, open the #1 high-pressure superheater #1 steam trap, #1 high-pressure superheater #2 steam trap, #1 high-pressure superheater #3 steam trap, #2 high-pressure superheater steam trap, #3 high-pressure superheater steam trap, high-level first-stage desuperheater outlet steam trap, high-level second-stage desuperheater outlet steam trap,

[0022] LC02: Waiting for the set time,

[0023] LC03: Check whether the engine has been ignited and the high-pressure main steam pressure is greater than 0.75MPa. If yes, proceed to the next step, otherwise return to the previous step.

[0024] LC04: Close #1 high pressure superheater #1 trap, #1 high pressure superheater #2 trap, #1 high pressure superheater #3 trap, #2 high pressure superheater trap, #3 high pressure superheater trap,

[0025] LC05: Waiting for the set time;

[0026] The subgroup sequential control program for hot start at the furnace side is:

[0027] LH01: Close all steam traps on the furnace side, that is, close the #1 high-pressure superheater #1 steam trap, #1 high-pressure superheater #2 steam trap, #1 high-pressure superheater #3 steam trap, #2 high-pressure superheater steam trap, #3 high-pressure superheater steam trap, high-level first-stage desuperheater outlet steam trap, high-level second-stage desuperheater outlet steam trap,

[0028] LH02: Waiting for the set time,

[0029] LH03: Check whether the engine has been ignited, delay 15s, if so, proceed to the next step,

[0030] LH04: Open #1 high pressure superheater #1 drain valve, #1 high pressure superheater #2 drain valve, #1 high pressure superheater #3 drain valve, and put the high pressure system pipeline drain SLC into operation.

[0031] LH05: Check the program waiting time, or the high pressure bypass or high pressure main steam regulating valve is open. If so, proceed to the next step.

[0032] LH06: Open #2 high pressure superheater drain valve and #3 high pressure superheater drain valve.

[0033] LH07: Check the program waiting time, or the high pressure bypass or high pressure main steam regulating valve is open. If so, proceed to the next step.

[0034] LH08: High-pressure main steam pressure>0.75MPa, and #3 high-pressure superheater outlet temperature superheat>5℃,

[0035] LH09: Close #2 high pressure superheater drain valve and #3 high pressure superheater drain valve.

[0036] LH10: Waiting for the set time,

[0037] LH11: Check that the high-pressure main steam pressure is greater than 0.75MPa and the outlet temperature of #1 high-pressure superheater is greater than 5°C

[0038] LH12: Close #1 high pressure superheater #1 trap, #1 high pressure superheater #2 trap, #1 high pressure superheater #3 trap and wait for the set time;

[0039] The subgroup sequence control procedure for cold start on the machine side is:

[0040] JC01: Open the drain valve before the high-pressure main steam electric valve, the drain valve after the high-pressure main steam electric valve, the primary drain valve before the high-pressure main steam valve, the electric valve from the high-pressure main steam to the medium-pressure warm-up pipe, and the secondary drain valve before the high-pressure main steam valve to 100%.

[0041] JC02: Waiting for the set time,

[0042] JC03: Check that the engine has been ignited, the high-pressure main steam pressure is greater than 0.75MPa, and the temperature of the lower wall of the high-pressure main steam pipeline is greater than 200℃. If so, proceed to the next step.

[0043] JC04: Close the secondary drain valve in front of the high-pressure main steam valve to 40%, close the drain valve in front of the high-pressure main steam electric valve,

[0044] JC05: The opening of the secondary drain valve before the high-pressure main steam valve is less than 45%

[0045] JC06: Check if the turbine speed is > 14Hz. If so, proceed to the next step.

[0046] JC07: Close the primary drain valve in front of the high-pressure main steam valve, the secondary drain valve in front of the high-pressure main steam valve, and the drain valve after the high-pressure main steam electric valve, and start the high-pressure main steam system drain SLC.

[0047] JC08: Waiting for the set time,

[0048] JC09: Check SSS clutch engagement, delay setting time, if yes, go to next step;

[0049] The subgroup sequence control procedure for hot start on the machine side is:

[0050] JH01: Close the drain valve before the high-pressure main steam electric valve, the drain valve after the high-pressure main steam electric valve, the primary drain valve before the high-pressure main steam valve, the secondary drain valve before the high-pressure main steam valve, and the electric valve from the high-pressure main steam to the medium-pressure heating pipe.

[0051] JH02: Waiting for the set time,

[0052] JH03: Check that the engine has been ignited, the high-pressure bypass valve has been opened (greater than 5%), the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than -25°C, and the high-pressure main steam pressure is greater than 0.75Mpa. If so, proceed to the next step

[0053] JH04: Open the drain valve in front of the high-pressure main steam electric valve.

[0054] JH05: Check that the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than -5°C.

[0055] JH06: Open the drain valve behind the high-pressure main steam electric valve, the primary drain valve in front of the high-pressure main steam valve, and the secondary drain valve in front of the high-pressure main steam valve to 40%.

[0056] JH07: Waiting for the set time, the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than 5°C, and the superheat of the steam trap before the high-pressure main steam electric valve is greater than 27.8°C.

[0057] JH08: Close the drain valve in front of the high-pressure main steam electric valve, and open the electric valve from the high-pressure main steam to the medium-pressure heating pipe.

[0058] JH09: Check that the electric valve from the high-pressure main steam to the medium-pressure heating pipe is open, the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than 30°C, and the superheat of the steam trap after the high-pressure main steam electric valve is greater than 27.8°C. If so, proceed to the next step.

[0059] JH10: Close the drain valve after the high-pressure main steam electric valve.

[0060] JH11: Check if the turbine speed is > 14Hz. If so, proceed to the next step.

[0061] JH12: Close the primary drain valve and secondary drain valve in front of the high-pressure main steam valve, and start the high-pressure main steam system drain SLC.

[0062] JH13: Waiting for the set time,

[0063] JH14: SSS clutch engages, delay 15s, if yes, proceed to next step.

[0064] The subgroup sequence control procedure for draining the high-pressure main steam system on the shutdown furnace side is:

[0065] L21: The generator is disconnected and the engine is shut down.

[0066] L22: Evacuate and check the interlocking protection control program of the sub-circuit of high-pressure pipeline and superheater water supply.

[0067] L23: Open the #1 high pressure superheater #1 trap, #1 high pressure superheater #2 trap, #1 high pressure superheater #3 trap, #2 high pressure superheater trap, #3 high pressure superheater trap, high pressure first desuperheater outlet trap, high pressure second desuperheater outlet trap,

[0068] L24: Waiting for the set time,

[0069] L25: outage ends;

[0070] The subgroup sequence control procedure for draining the high-pressure main steam system on the shutdown unit side is:

[0071] J21: The generator is disconnected and the engine is shut down.

[0072] J22: Evacuate and check the sub-circuit interlocking protection control program of the high-pressure main steam system drain on the machine side.

[0073] J23: Shut down the drain valve after the high-pressure main steam electric valve, the primary drain valve before the high-pressure main steam valve, the secondary drain valve before the high-pressure main steam valve, and the electric valve from the high-pressure main steam to the medium-pressure heating pipe.

[0074] J24: Waiting for the set time,

[0075] J25: The outage is over.

[0076] Compared with the prior art, the advantages of the present invention are:

[0077] (1) It can automatically determine whether the unit is started in cold or hot state according to the start-up signal or the operating conditions of the thermal system and execute the corresponding drain control strategy, taking into account the drain requirements of the unit when starting in cold and hot states.

[0078] (2) By fixing the opening and closing operation sequence of each steam trap and remotely controlling it by computer, the problems of heavy workload, slow start-up speed and possible misoperation affecting the normal operation of the unit when the steam trap is opened and closed manually are avoided. It also solves the defect that when using independent interlocking protection logic to execute hot start steam trap, the operating conditions of the thermal system do not meet the opening conditions of certain valves and the operator still needs to open them manually.

[0079] (3) Sequential control is used to execute the opening and closing operations of each steam trap. The steps are strictly arranged and have clear meanings, which is convenient for computer execution and program modification. BRIEF DESCRIPTION OF THE DRAWINGS

[0080] Figure 1 To start the subgroup sequence control program for draining the high-pressure main steam system on the boiler side;

[0081] Figure 2 It is the subgroup sequence control program for draining the high pressure main steam system on the starter side;

[0082] Figure 3 It is the subgroup sequence control program for draining the high pressure main steam system on the shutdown furnace side;

[0083] Figure 4 It is the subgroup sequence control program for draining the high pressure main steam system on the shutdown machine side;

[0084] Figure 5 Structural diagram of the high-pressure main steam system of a gas-steam combined cycle unit;

[0085] Explanation of the numbers in the figure: #1 high-pressure superheater 1, #2 high-pressure superheater 2, #3 high-pressure superheater 3, higher than the first-stage desuperheater 4, high-pressure main steam electric valve 5, higher than the first-stage desuperheater outlet drain valve 6, higher than the second-stage desuperheater outlet drain valve 7, #3 high-pressure superheater drain valve 8, #2 high-pressure superheater drain valve 9, #1 high-pressure superheater #3 drain valve 10, #1 high-pressure superheater #2 drain valve 12, #1 high-pressure superheater #1 drain valve 11, high-pressure main steam electric valve front drain valve 13, high-pressure main steam electric valve rear drain valve 14, high-pressure main steam valve front drain primary valve 15, high-pressure main steam valve front drain secondary valve 16, high-pressure main steam to medium-pressure warm pipe electric valve 17, higher than the second-stage desuperheater 18, steam turbine 19. DETAILED DESCRIPTION

[0086] The present invention is described in detail below in conjunction with specific embodiments and accompanying drawings.

[0087] like Figure 5 As shown, the schematic diagram of the high-pressure main steam system structure of the gas-steam combined cycle unit. The high-pressure main steam flows to #1 high-pressure superheater 1, high-pass second-stage desuperheater 4, #2 high-pressure superheater 2, #3 high-pressure superheater 3, high-pass first-stage desuperheater 18, and high-pressure main steam electric valve 5 / turbine 19.

[0088] Among them, #1 high-pressure superheater 1 is equipped with #1 high-pressure superheater #3 steam trap 10, #1 high-pressure superheater #2 steam trap 12 and #1 high-pressure superheater #1 steam trap 11, #2 high-pressure superheater 2 is equipped with #2 high-pressure superheater steam trap 9, #3 high-pressure superheater 3 is equipped with #3 high-pressure superheater steam trap 8, the higher than the first level desuperheater 4 is equipped with the higher than the first level desuperheater outlet steam trap 6, and the higher than the second level desuperheater 18 is equipped with the higher than the second level desuperheater outlet steam trap 7. They constitute the furnace side of the gas-steam combined cycle unit. The various steam traps among them, close to the side of the waste heat boiler, are collectively referred to as furnace side steam traps.

[0089] Among them, a high-pressure main steam electric valve front drain valve 13 is arranged in front of the high-pressure main steam electric valve 5, a high-pressure main steam electric valve rear drain valve 14 is arranged in the rear of the high-pressure main steam electric valve 5, and a high-pressure main steam valve front drain primary valve 15 and a high-pressure main steam valve front drain secondary valve 16 are arranged in the rear of the high-pressure main steam electric valve rear drain valve 14, and the high-pressure main steam flows from the high-pressure main steam valve front drain secondary valve 16 to the high-pressure main steam to medium-pressure warm pipe electric valve 17 and the steam turbine 19. Each of these drain valves, close to the steam turbine side, is collectively referred to as a machine-side drain valve.

[0090] As shown in Figure 5, the high-pressure main steam system of the steam combined cycle unit, the cold state refers to the state where the unit is shut down for a long time and the temperature of the internal metal parts is close to the ambient temperature, and the hot state refers to the state where the unit is shut down for a short time and the internal metal parts still maintain a high temperature. In view of the difference between the cold state and the hot state, it is necessary to control the drainage separately. In addition, the furnace side and the machine side are controlled separately.

[0091] In the present invention, the subgroup sequential control program is referred to as SGC, which refers to the sequential control program corresponding to the furnace side or the machine side. The sub-loop interlock protection control program is referred to as SLC, which is a part of the interlock protection control program and corresponds to a valve. SLC is that each steam trap is automatically opened based on at least one condition as a criterion: one is that the liquid level of the steam trap collector of the unit's thermal system rises to a high level, that is, the steam trap collector is a high-level liquid switch. When the liquid level of the steam trap rises to a high level, the high-level liquid switch instructs the corresponding steam trap to open the drain; the second is that the superheat of the unit's thermal system is lower than 13.9°C; otherwise, it is closed.

[0092] like Figure 1 The following is a subgroup sequential control program for starting the boiler side high pressure main steam system drain. After the boiler side drain SGC is started, the following sequential control program is executed:

[0093] L11: Evacuate and inspect the high-pressure superheater and high-pressure system pipeline drain SLC.

[0094] L12: Check if the cold start signal is activated or the high-pressure main steam pressure is less than 0.75MPa. If so, execute the furnace side cold start LC procedure, otherwise, execute the furnace side hot start LH procedure. After the furnace side cold start procedure or furnace side hot start procedure is completed, proceed to the next step;

[0095] L13: Put high-pressure superheater drain SLC and high-pressure system pipeline drain SLC into operation;

[0096] L14: Check whether the high-pressure superheater drain SLC and the high-pressure system pipeline drain SLC are in operation; if so, proceed to the next step, if not, return to the previous step;

[0097] L15: Startup completed.

[0098] The sequence of steps to execute the furnace side cold start procedure is:

[0099] LC01: Open all steam traps on the furnace side, i.e., open steam trap 11 of #1 high pressure superheater #1, steam trap 12 of #1 high pressure superheater #2, steam trap 10 of #1 high pressure superheater #3, steam trap 9 of #2 high pressure superheater, steam trap 8 of #3 high pressure superheater, steam trap 6 of the outlet of the first desuperheater, steam trap 7 of the outlet of the second desuperheater;

[0100] LC02: Wait for the set time 30s;

[0101] LC03: Check whether the engine has been ignited and the high-pressure main steam pressure is greater than 0.75MPa. If yes, proceed to the next step, otherwise return to the previous step;

[0102] LC04: Close #1 high-pressure superheater #1 trap, #1 high-pressure superheater #2 trap, #1 high-pressure superheater #3 trap, #2 high-pressure superheater trap, #3 high-pressure superheater trap;

[0103] LC05: Wait for the set time 30s.

[0104] The sequence of steps to execute the furnace side hot start procedure is:

[0105] LH01: Close all steam traps on the furnace side, that is, close the #1 high-pressure superheater #1 steam trap 11, #1 high-pressure superheater #2 steam trap 12, #1 high-pressure superheater #3 steam trap 10, #2 high-pressure superheater steam trap 9, #3 high-pressure superheater steam trap 8, high-level first-stage desuperheater outlet steam trap 6, high-level second-stage desuperheater outlet steam trap 7,

[0106] LH02: Wait for the set time 30s,

[0107] LH03: Check whether the engine has been ignited, delay 15s, if so, proceed to the next step,

[0108] LH04: Open #1 high pressure superheater #1 drain valve, #1 high pressure superheater #2 drain valve, #1 high pressure superheater #3 drain valve, and put the high pressure system pipeline drain SLC into operation.

[0109] LH05: Check the program and wait for the set time of 30s, or the high-pressure bypass or high-pressure main steam regulating valve is open. If so, proceed to the next step.

[0110] LH06: Open #2 high pressure superheater drain valve and #3 high pressure superheater drain valve.

[0111] LH07: Check the program and wait for the set time of 30s, or the high-pressure bypass or high-pressure main steam regulating valve is open. If so, proceed to the next step.

[0112] LH08: High-pressure main steam pressure>0.75MPa, and #3 high-pressure superheater outlet temperature superheat>5℃,

[0113] LH09: Close #2 high pressure superheater drain valve and #3 high pressure superheater drain valve.

[0114] LH10: Wait for the set time 5s,

[0115] LH11: Check that the high-pressure main steam pressure is greater than 0.75MPa and the outlet temperature of #1 high-pressure superheater is greater than 5°C

[0116] LH12: Close the #1 high pressure superheater #1 drain valve, #1 high pressure superheater #2 drain valve, #1 high pressure superheater #3 drain valve and wait for the set time of 5s.

[0117] like Figure 3 The following is the subgroup sequence control procedure for draining the high-pressure main steam system on the shutdown furnace side:

[0118] L21: The generator is disconnected and the engine is shut down;

[0119] L22: Evacuate and check the sub-circuit interlock protection control procedures of the high-pressure pipeline and superheater drain;

[0120] L23: Open the #1 high pressure superheater #1 trap 11, #1 high pressure superheater #2 trap 12, #1 high pressure superheater #3 trap 10, #2 high pressure superheater trap 9, #3 high pressure superheater trap 8, high pressure first desuperheater outlet trap 6, high pressure second desuperheater outlet trap 7 on the furnace side;

[0121] L24: Wait for the set time 30s;

[0122] L25: The outage is over.

[0123] like Figure 2The following is a subgroup sequential control procedure for starting the machine side high pressure main steam system drain. After the machine side drain SGC is started, the following sequential control procedure is executed:

[0124] J11: Evacuate and check the SLC of the high-pressure main steam system on the machine side;

[0125] J12: Check if the cold start signal is activated or the high-pressure main steam pressure is less than 0.75MPa. If so, execute the cold start JC procedure on the machine side, otherwise, execute the hot start JH procedure on the machine side. After the cold start procedure on the furnace side or the hot start procedure on the furnace side is completed, proceed to the next step.

[0126] J13: Close the electric valve from high-pressure main steam to medium-pressure heating pipe;

[0127] J14: The electric valve from high-pressure main steam to medium-pressure heating pipe is closed. If so, proceed to the next step. If not, return to the previous step.

[0128] J15: Startup completed.

[0129] The sequence of steps to execute the cold start JC procedure on the machine side is:

[0130] JC01: Open the drain valve before the high-pressure main steam electric valve, the drain valve after the high-pressure main steam electric valve, the primary drain valve before the high-pressure main steam valve, the electric valve from the high-pressure main steam to the medium-pressure warm-up pipe, and the secondary drain valve before the high-pressure main steam valve to 100%.

[0131] JC02: Wait for the set time 30s,

[0132] JC03: Check that the engine has been ignited, the high-pressure main steam pressure is greater than 0.75MPa, and the temperature of the lower wall of the high-pressure main steam pipeline is greater than 200℃. If so, proceed to the next step.

[0133] JC04: Close the secondary drain valve in front of the high-pressure main steam valve to 40%, close the drain valve in front of the high-pressure main steam electric valve,

[0134] JC05: The opening of the secondary drain valve before the high-pressure main steam valve is less than 45%

[0135] JC06: Check if the turbine speed is > 14Hz. If so, proceed to the next step.

[0136] JC07: Close the primary drain valve in front of the high-pressure main steam valve, the secondary drain valve in front of the high-pressure main steam valve, and the drain valve after the high-pressure main steam electric valve, and start the high-pressure main steam system drain SLC.

[0137] JC08: Wait for the set time 30s,

[0138] JC09: Check SSS clutch engagement, delay setting time 5min, if yes, proceed to next step;

[0139] The sequence of steps to execute the machine-side hot start JC program is:

[0140] JH01: Close the drain valve before the high-pressure main steam electric valve, the drain valve after the high-pressure main steam electric valve, the primary drain valve before the high-pressure main steam valve, the secondary drain valve before the high-pressure main steam valve, and the electric valve from the high-pressure main steam to the medium-pressure heating pipe.

[0141] JH02: Wait 60 seconds,

[0142] JH03: Check that the engine has been ignited, the high-pressure bypass valve has been opened more than 5%, the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than -25°C, and the high-pressure main steam pressure is greater than 0.75Mpa. If so, proceed to the next step

[0143] JH04: Open the drain valve in front of the high-pressure main steam electric valve.

[0144] JH05: Check that the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than -5°C.

[0145] JH06: Open the drain valve behind the high-pressure main steam electric valve, the primary drain valve in front of the high-pressure main steam valve, and the secondary drain valve in front of the high-pressure main steam valve to 40%.

[0146] JH07: Wait for 1 minute, the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than 5°C, and the superheat of the steam trap before the high-pressure main steam electric valve is greater than 27.8°C.

[0147] JH08: Close the drain valve in front of the high-pressure main steam electric valve, and open the electric valve from the high-pressure main steam to the medium-pressure heating pipe.

[0148] JH09: Check that the electric valve from the high-pressure main steam to the medium-pressure heating pipe is open, the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than 30°C, and the superheat of the steam trap after the high-pressure main steam electric valve is greater than 27.8°C. If so, proceed to the next step.

[0149] JH10: Close the drain valve after the high-pressure main steam electric valve.

[0150] JH11: Check if the turbine speed is > 14Hz. If so, proceed to the next step.

[0151] JH12: Close the primary drain valve and secondary drain valve in front of the high-pressure main steam valve, and start the high-pressure main steam system drain SLC.

[0152] JH13: Wait 30 seconds,

[0153] JH14: SSS clutch engages, delay 15s, if yes, proceed to next step.

[0154] like Figure 4The following is the subgroup sequence control procedure for draining the high-pressure main steam system on the shutdown unit side:

[0155] J21: The generator is disconnected and the engine is shut down.

[0156] J22: Evacuate and check the sub-circuit interlocking protection control program of the high-pressure main steam system drain on the machine side.

[0157] J23: Shut down the drain valve 14 after the high-pressure main steam electric valve, the primary drain valve 15 before the high-pressure main steam valve, the secondary drain valve 16 before the high-pressure main steam valve, and the electric valve 17 for the high-pressure main steam to medium-pressure warm-up pipe.

[0158] J24: Wait for the set time 30s,

[0159] J25: The outage is over.

[0160] As mentioned earlier,

[0161] (1) The switch conditions of the steam trap of the high-pressure main steam system on the furnace side are:

[0162] Automatic opening: The sub-circuit interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation, the corresponding temperature superheat of the pipeline where the steam trap is located is lower than 13.9℃, or the step opening instruction in the sub-group sequence control program of the boiler side high-pressure main steam system drain is started.

[0163] Automatic closing: the sub-circuit interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation, the corresponding temperature superheat of the pipeline where the steam trap is located is greater than 27.8℃, or the step closing instruction in the sub-group sequence control program of the boiler side high-pressure main steam system drain is started;

[0164] (2) The switch conditions of the steam trap of the high-pressure main steam system on the machine side are:

[0165] Automatic opening: The sub-circuit interlock protection control program of the high-pressure main steam system pipeline drain is put into operation and the liquid level of the corresponding drain collector of the pipeline where the drain valve is located rises to a high level, that is, the drain collector is a high-level liquid switch. When the liquid level of the drain valve rises to a high level, the high-level liquid switch instructs the corresponding drain valve to open the drain, or the step opening instruction in the sub-group sequence control program of the high-pressure main steam system drain on the starter side is started.

[0166] Automatic closing: the sub-loop interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation and the liquid level of the corresponding drain collector of the pipeline where the drain valve is located drops to a low level, that is, the drain collector is a high-level liquid switch. When the liquid level of the drain valve drops to a low level, the high-level liquid switch instructs the corresponding drain valve to close the drain, or the step closing instruction in the sub-group sequential control program of the high-pressure main steam system drain on the starter side is issued.

Claims

1. A one-button drain control method for a high-pressure main steam system of a gas-steam combined cycle unit, characterized by: The unit comprises a #1 high-pressure superheater (1), a #2 high-pressure superheater (2), a #3 high-pressure superheater (3), a high-pressure first-stage desuperheater (4), a high-pressure second-stage desuperheater (18), a #1 high-pressure superheater #1 trap (11), a #1 high-pressure superheater #2 trap (12), a #1 high-pressure superheater #3 trap (10), a #2 high-pressure superheater trap (9), a #3 high-pressure superheater trap (8), a high-pressure first-stage desuperheater outlet trap (6), a high-pressure second-stage desuperheater outlet trap (7) and a high-pressure main steam electric valve (5), a high-pressure main steam electric valve front trap (13), a high-pressure main steam electric valve rear trap (14), a high-pressure main steam valve front trap primary valve (15), and a high-pressure main steam valve front trap secondary valve (16) on the machine side; The boiler side drain and the machine side drain are executed independently; When executing boiler side draining: determine whether the unit is in cold or hot state; when the unit is in cold state, start automatic draining according to the sub-group sequence control program of boiler side cold start (LC); when the unit is in hot state, start automatic draining according to the sub-group sequence control program of boiler side hot start (LH); When executing machine side drain: determine whether the unit is in cold or hot state; when the unit is in cold state, start automatic drain according to the sub-group sequence control program of machine side cold start (JC); when the unit is in hot state, start automatic drain according to the sub-group sequence control program of machine side hot start (JH).

2. The one-button drain control method for a high-pressure main steam system of a gas-steam combined cycle unit according to claim 1 is characterized in that: When performing boiler-side draining, the startup is terminated on the condition that the sub-circuit interlocking protection control programs of the high-pressure superheater and the high-pressure system pipeline have been put into operation; When the machine side is drained, the start-up is terminated on the condition that the high-pressure main steam to medium-pressure warm-up pipe electric valve (17) has been closed.

3. The one-button drain control method for a high-pressure main steam system of a gas-steam combined cycle unit according to claim 2 is characterized in that: The sub-loop interlocking protection control procedure is that each steam trap is automatically opened based on at least one condition: one is that the liquid level of the steam trap collector of the unit's thermal system rises to a high level, and the other is that the superheat of the unit's thermal system is lower than a certain threshold; otherwise it is closed.

4. The one-key drain control method for a high-pressure main steam system of a gas-steam combined cycle unit according to claim 1, 2 or 3, characterized in that: When performing boiler-side draining and machine-side draining, the unit is judged to be in a cold state when the cold start signal is activated or the high-pressure main steam pressure is less than 0.75MPa, otherwise it is judged to be in a hot state.

5. The one-button drain control method for a high-pressure main steam system of a gas-steam combined cycle unit according to claim 1, 2 or 3, characterized in that: (1) The switch conditions of the steam trap of the high-pressure main steam system on the furnace side are: Automatic opening: The sub-circuit interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation and the corresponding temperature superheat of the pipeline where the steam trap is located is lower than 13.9℃, or the step opening instruction in the sub-group sequence control program of the boiler side high-pressure main steam system drain is started. Automatic closing: The sub-circuit interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation and the corresponding superheat of the pipe where the steam trap is located is greater than 27.8℃, or the step closing instruction in the sub-group sequence control program of the boiler side high-pressure main steam system drain is started; (2) The switch conditions of the steam trap of the high-pressure main steam system on the machine side are: Automatic opening: The sub-circuit interlock protection control program of the high-pressure main steam system pipeline drain is put into operation and the liquid level of the corresponding drain collector of the pipeline where the drain valve is located rises to a high level, or the step opening instruction in the sub-group sequence control program of the high-pressure main steam system drain on the starter side is started. Automatic closing: The sub-loop interlocking protection control program of the high-pressure main steam system pipeline drain is put into operation and the liquid level of the corresponding drain collector of the pipeline where the drain valve is located drops to a low level, or the step closing instruction in the sub-group sequential control program of the high-pressure main steam system drain on the starter side is initiated.

6. The one-button drain control method for a high-pressure main steam system of a gas-steam combined cycle unit according to claim 1, 2 or 3, characterized in that: The subgroup sequential control program for cold start of the furnace side is: LC01: Open all steam traps on the furnace side, i.e., open the steam trap (11) of #1 high pressure superheater #1, steam trap (12) of #1 high pressure superheater #2, steam trap (10) of #1 high pressure superheater #3, steam trap (9) of #2 high pressure superheater, steam trap (8) of #3 high pressure superheater, steam trap (6) of the first desuperheater outlet, steam trap (7) of the second desuperheater outlet. LC02: Waiting for the set time, LC03: Check whether the engine has been ignited and the high-pressure main steam pressure is greater than 0.75MPa. If yes, proceed to the next step, otherwise return to the previous step. LC04: Close #1 high pressure superheater #1 trap, #1 high pressure superheater #2 trap, #1 high pressure superheater #3 trap, #2 high pressure superheater trap, #3 high pressure superheater trap, LC05: Waiting for the set time; The subgroup sequential control program for hot start at the furnace side is: LH01: Close all steam traps on the furnace side, i.e., close the #1 high pressure superheater #1 steam trap (11), #1 high pressure superheater #2 steam trap (12), #1 high pressure superheater #3 steam trap (10), #2 high pressure superheater steam trap (9), #3 high pressure superheater steam trap (8), high pressure first stage desuperheater outlet steam trap (6), high pressure second stage desuperheater outlet steam trap (7). LH02: Waiting for the set time, LH03: Check whether the engine has been ignited, delay 15s, if so, proceed to the next step, LH04: Open #1 high pressure superheater #1 drain valve, #1 high pressure superheater #2 drain valve, #1 high pressure superheater #3 drain valve, and put the high pressure system pipeline drain SLC into operation. LH05: Check the program waiting time, or the high pressure bypass or high pressure main steam regulating valve is open. If so, proceed to the next step. LH06: Open #2 high pressure superheater drain valve and #3 high pressure superheater drain valve. LH07: Check the program waiting time, or the high pressure bypass or high pressure main steam regulating valve is open. If so, proceed to the next step. LH08: High-pressure main steam pressure>0.75MPa, and #3 high-pressure superheater outlet temperature superheat>5℃, LH09: Close #2 high pressure superheater drain valve and #3 high pressure superheater drain valve. LH10: Waiting for the set time, LH11: Check that the high-pressure main steam pressure is greater than 0.75 MPa and the outlet temperature of #1 high-pressure superheater is greater than 5°C LH12: Close #1 high pressure superheater #1 trap, #1 high pressure superheater #2 trap, #1 high pressure superheater #3 trap and wait for the set time; The subgroup sequence control procedure for cold start on the machine side is: JC01: Open the drain valve before the high-pressure main steam electric valve, the drain valve after the high-pressure main steam electric valve, the primary drain valve before the high-pressure main steam valve, the electric valve from the high-pressure main steam to the medium-pressure warm-up pipe, and the secondary drain valve before the high-pressure main steam valve to 100%. JC02: Waiting for the set time, JC03: Check that the engine has been ignited, the high-pressure main steam pressure is greater than 0.75MPa, and the temperature of the lower wall of the high-pressure main steam pipeline is greater than 200℃. If so, proceed to the next step. JC04: Close the secondary drain valve in front of the high-pressure main steam valve to 40%, close the drain valve in front of the high-pressure main steam electric valve, JC05: The opening of the secondary drain valve before the high-pressure main steam valve is less than 45% JC06: Check if the turbine speed is > 14Hz. If so, proceed to the next step. JC07: Close the primary drain valve in front of the high-pressure main steam valve, the secondary drain valve in front of the high-pressure main steam valve, and the drain valve after the high-pressure main steam electric valve, and put the high-pressure main steam system drain SLC into operation. JC08: Waiting for the set time, JC09: Check SSS clutch engagement, delay setting time 5min, if yes, proceed to next step; The subgroup sequence control procedure for hot start on the machine side is: JH01: Close the drain valve before the high-pressure main steam electric valve, the drain valve after the high-pressure main steam electric valve, the primary drain valve before the high-pressure main steam valve, the secondary drain valve before the high-pressure main steam valve, and the electric valve from the high-pressure main steam to the medium-pressure heating pipe. JH02: Waiting for the set time, JH03: Check that the engine has been ignited, the high-pressure bypass valve has been opened more than 5%, the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than -25°C, and the high-pressure main steam pressure is greater than 0.75Mpa. If so, proceed to the next step JH04: Open the drain valve in front of the high-pressure main steam electric valve. JH05: Check that the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than -5°C. JH06: Open the drain valve behind the high-pressure main steam electric valve, the primary drain valve in front of the high-pressure main steam valve, and the secondary drain valve in front of the high-pressure main steam valve to 40%. JH07: Waiting for the set time, the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than 5°C, and the superheat of the steam trap before the high-pressure main steam electric valve is greater than 27.8°C. JH08: Close the drain valve in front of the high-pressure main steam electric valve, and open the electric valve from the high-pressure main steam to the medium-pressure heating pipe. JH09: Check that the electric valve from the high-pressure main steam to the medium-pressure heating pipe is open, the difference between the main steam temperature before the high-pressure bypass and the temperature before the high-pressure main steam valve is greater than 30°C, and the superheat of the steam trap after the high-pressure main steam electric valve is greater than 27.8°C. If so, proceed to the next step. JH10: Close the drain valve after the high-pressure main steam electric valve. JH11: Check if the turbine speed is > 14Hz. If so, proceed to the next step. JH12: Close the primary drain valve and secondary drain valve in front of the high-pressure main steam valve, and start the high-pressure main steam system drain SLC. JH13: Waiting for the set time, JH14: SSS clutch engages, delay 15s, if yes, proceed to next step.

7. The one-button drain control method for a high-pressure main steam system of a gas-steam combined cycle unit according to claim 1, 2 or 3, characterized in that: The subgroup sequence control procedure for draining the high-pressure main steam system on the shutdown furnace side is: L21: The generator is disconnected and the engine is shut down. L22: Evacuate and check the interlocking protection control program of the sub-circuit of high-pressure pipeline and superheater water supply. L23: Open the #1 high pressure superheater #1 drain valve (11), #1 high pressure superheater #2 drain valve (12), #1 high pressure superheater #3 drain valve (10), #2 high pressure superheater drain valve (9), #3 high pressure superheater drain valve (8), high pressure first stage desuperheater outlet drain valve (6), high pressure second stage desuperheater outlet drain valve (7) on the furnace side. L24: Waiting for the set time, L25: outage ends; The subgroup sequence control procedure for draining the high-pressure main steam system on the shutdown unit side is: J21: The generator is disconnected and the engine is shut down. J22: Evacuate and check the sub-circuit interlocking protection control program of the high-pressure main steam system drain on the machine side. J23: Close the drain valve (14) after the high-pressure main steam electric valve, the primary drain valve (15) before the high-pressure main steam valve, the secondary drain valve (16) before the high-pressure main steam valve, and the electric valve (17) from the high-pressure main steam to the medium-pressure warm-up pipe. J24: Waiting for the set time, J25: The outage is over.

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