JP4168485B2 - High and low pressure turbine bypass valve control method for boiler equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high- and low-pressure turbine bypass valve control method for boiler equipment.
[0002]
[Prior art]
Generally, as shown in FIG. 7, the boiler equipment is provided with a high-pressure turbine 1 and a low-pressure turbine 2, and main steam heated by a boiler superheater (not shown) is passed through a main steam line 3. The high-pressure turbine 1 is driven to generate power by driving the high-pressure turbine 1, and the steam after driving the high-pressure turbine 1 is guided to a boiler reheater 5 through a reheat line 4. After being reheated by the heater 5, it is introduced into the low-pressure turbine 2, the low-pressure turbine 2 is driven to generate power, and the steam after driving the low-pressure turbine 2 is sent to the condenser 7 via the condensate line 6. Then, the steam is returned to the boiler feed water by the condenser 7 and circulated.
[0003]
Further, in the boiler facility, conventionally, a turbine bypass line 8 branched from the middle of the main steam line 3 and connected to the middle of the condensate line 6 between the low-pressure turbine 2 and the condenser 7 is provided. A turbine bypass valve 9 is provided in the middle of the bypass line 8, and the inlets of the high-pressure turbine 1 and the low-pressure turbine 2 are not shown before ventilation to the high-pressure turbine 1 and the low-pressure turbine 2 when the boiler equipment is started. The governor valve is closed, the turbine bypass valve 9 is opened, and the main steam that has not been sufficiently heated and raised from the boiler superheater flows through the turbine bypass line 8 and reheats the high pressure turbine 1. Bypassing the steam generator 5 and the low-pressure turbine 2 and led through the condensate line 6 between the low-pressure turbine 2 and the condenser 7 and circulated so that the main steam is sufficiently heated and pressurized. Thereafter, with the main steam pressure at the inlet of the high pressure turbine 1 maintained at a set value by adjusting the opening of the turbine bypass valve 9, the governor valves at the inlets of the high pressure turbine 1 and the low pressure turbine 2 are opened and ventilated. While shifting to normal operation, during normal operation, pressure control of the main steam at the inlet of the high-pressure turbine 1 is performed by adjusting the opening of the turbine bypass valve 9 in accordance with the load command. When it is desired to reduce the load suddenly due to equipment failure or the like in the boiler facility, the turbine bypass valve 9 is fully opened, the main steam is released to the turbine bypass line 8, and the main steam pressure introduced into the high-pressure turbine 1 is reduced. Things are also happening.
[0004]
[Problems to be solved by the invention]
However, as described above, before ventilation to the high-pressure turbine 1 and the low-pressure turbine 2 at the start-up of the boiler equipment, the turbine bypass valve 9 is opened and the main steam is guided to the turbine bypass line 8 so that the high-pressure turbine 1 and the reheater 5 are opened. Since the steam is not introduced into the reheater 5 until the governor valve at the inlet of the high pressure turbine 1 is opened and ventilated, it takes time until the boiler is warmed up and the startup time is reduced. Had the disadvantage of becoming longer.
[0005]
Therefore, a high-pressure turbine bypass line that bypasses the high-pressure turbine 1 and a low-pressure turbine bypass line that bypasses the low-pressure turbine 2 are separately provided, a high-pressure turbine bypass valve is provided in the middle of the high-pressure turbine bypass line, and the low-pressure turbine bypass By providing a low-pressure turbine bypass valve in the middle of the line, steam is introduced into the reheater 5 before venting to the high-pressure turbine 1 and the low-pressure turbine 2 when the boiler equipment is started up. Although shortening is also proposed, the concrete control method of the high pressure turbine bypass valve and the low pressure turbine bypass valve has not been established.
[0006]
In view of such circumstances, the present invention can shorten the boiler start-up time and reliably control the main steam pressure at the high-pressure turbine inlet and the reheat steam pressure at the low-pressure turbine inlet during normal operation. In addition, an object of the present invention is to provide a high and low pressure turbine bypass valve control method for boiler equipment that can cope with a sudden load reduction in an emergency.
[0007]
[Means for Solving the Problems]
The present invention includes a high pressure turbine bypass line branched from the middle of the main steam line and connected in the middle of the reheat line between the high pressure turbine and the reheater, and provided with a high pressure turbine bypass valve in the middle, a reheater, A low pressure turbine bypass line branched from the middle of the reheat line between the low pressure turbine and connected to the middle of the condensate line between the low pressure turbine and the condenser, and provided with a low pressure turbine bypass valve in the middle A boiler equipment high / low pressure turbine bypass valve control method comprising:
By opening the high-pressure turbine bypass valve opening command to eliminate the main steam pressure deviation between the main steam pressure and the main steam pressure set value based on the load command, the opening of the high-pressure turbine bypass valve is set to open the high-pressure turbine bypass valve based on the load command. In addition to adjusting within the range not exceeding the upper limit setting value,
A low-pressure turbine bypass valve opening command for eliminating a reheat steam pressure deviation between the reheat steam pressure and the reheat steam pressure set value based on the load command causes the opening of the low-pressure turbine bypass valve to be transferred to the high-pressure turbine bypass line. Boiler equipment characterized by adjusting in a range not to be lower than a low pressure turbine bypass valve opening lower limit set value for securing a bypass flow rate and not to exceed a low pressure turbine bypass valve opening upper limit set value based on a load command The present invention relates to a method for controlling a high and low pressure turbine bypass valve.
[0008]
According to the above means, the following operation can be obtained.
[0009]
The high-pressure turbine bypass valve opening command is used to eliminate the main steam pressure deviation between the main steam pressure and the main steam pressure set value based on the load command. The low pressure turbine bypass valve opening command is used to reduce the reheat steam pressure deviation between the reheat steam pressure and the reheat steam pressure set value based on the load command. The opening degree of the turbine bypass valve is not less than the lower limit setting value of the low pressure turbine bypass valve for ensuring the bypass flow rate flowing to the high pressure turbine bypass line, and the upper limit setting value of the low pressure turbine bypass valve based on the load command It is adjusted within the range not exceeding.
[0010]
Here, even if the high-pressure turbine and the low-pressure turbine inlet governor valve are closed and the high-pressure turbine bypass valve is opened before venting to the high-pressure turbine and the low-pressure turbine when the boiler equipment is started up, the main steam is regenerated. Since it is introduced into the heater, it takes less time for the boiler to warm up, and the startup time is shortened.
[0011]
The main steam pressure at the high pressure turbine inlet and the reheat steam pressure at the low pressure turbine inlet are basically controlled by adjusting the opening of the high pressure turbine bypass valve and the opening of the low pressure turbine bypass valve. However, the opening of the high pressure turbine bypass valve is adjusted within a range not exceeding the upper limit set value of the high pressure turbine bypass valve opening based on the load command, and the opening of the low pressure turbine bypass valve is adjusted based on the load command. Since the adjustment is made within a range not exceeding the bypass valve opening upper limit setting value, it is possible to prevent steam exceeding the allowable capacity of the condenser from being introduced into the condenser.
[0012]
Furthermore, the opening of the low-pressure turbine bypass valve is adjusted so as not to be less than a low-pressure turbine bypass valve opening lower limit setting value for ensuring a bypass flow rate flowing to the high-pressure turbine bypass line. When the amount of reheat steam that is the same as the bypass flow rate of the main steam that flows to the bypass line flows to the low-pressure turbine bypass line, and you want to reduce the load suddenly due to equipment failure in the boiler facility, The main steam that has escaped to the high-pressure turbine bypass line is released to the low-pressure turbine bypass line as the same amount of reheated steam, ensuring the bypass function, and a part of the main steam that bypasses the high-pressure turbine is reheated. It will not be supplied to the low-pressure turbine as steam, and will be able to handle sudden load reduction. .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0014]
FIG. 1 is an example of an embodiment for carrying out the present invention. In the figure, the same reference numerals as those in FIG. 7 denote the same parts. A high-pressure turbine bypass line 10 connected in the middle of the reheat line 4 between the heater 5 and the high-pressure turbine bypass valve 11 is provided in the middle of the high-pressure turbine bypass line 10, and the reheater 5 and the low-pressure turbine 2 A low pressure turbine bypass line 12 is provided which branches from the middle of the reheat line 4 between the two and is connected to the middle of the condensate line 6 between the low pressure turbine 2 and the condenser 7. A turbine bypass valve 13 is provided.
[0015]
Further, a main steam pressure detector 15 for detecting the main steam pressure 14 introduced into the high pressure turbine 1 and a reheat steam pressure detector 17 for detecting the reheat steam pressure 16 introduced into the low pressure turbine 2 are provided. Based on the main steam pressure 14 detected by the main steam pressure detector 15 and the reheat steam pressure 16 detected by the reheat steam pressure detector 17, the high pressure turbine bypass valve opening command 18 and the low pressure turbine A control device 20 that outputs a bypass valve opening command 19 is provided.
[0016]
As shown in FIG.
A first function generator 23 for obtaining and outputting a main steam pressure set value 22 based on a load command 21;
The difference between the main steam pressure 14 detected by the main steam pressure detector 15 and the main steam pressure set value 22 output from the first function generator 23 is obtained, and a subtracter 25 that outputs a main steam pressure deviation 24 is obtained. When,
A proportional-integral controller 27 for proportionally integrating the main steam pressure deviation 24 output from the subtractor 25 and outputting a high-pressure turbine bypass valve opening command 26 for eliminating the main steam pressure deviation 24;
A second function generator 29 for obtaining and outputting a high-pressure turbine bypass valve opening upper limit set value 28 based on the load command 21;
The lower one of the high-pressure turbine bypass valve opening upper limit set value 28 output from the second function generator 29 and the high-pressure turbine bypass valve opening command 26 output from the proportional-plus-integral regulator 27 is selected to select a high-pressure turbine bypass. A low selector 30 that outputs the valve opening command 18 to the high-pressure turbine bypass valve 11;
A third function generator 32 for obtaining and outputting a reheat steam pressure set value 31 based on the load command 21;
A difference between the reheat steam pressure 16 detected by the reheat steam pressure detector 17 and the reheat steam pressure set value 31 output from the third function generator 32 is obtained, and a reheat steam pressure deviation 33 is output. A subtractor 34,
A proportional integration controller 36 for proportionally integrating the reheat steam pressure deviation 33 output from the subtractor 34 and outputting a low-pressure turbine bypass valve opening command 35 for eliminating the reheat steam pressure deviation 33;
Bypassing the main steam pressure 14 detected by the main steam pressure detector 15 with the high-pressure turbine bypass valve opening command 18 output to the high-pressure turbine bypass valve 11, the bypass flow rate of the main steam flowing to the high-pressure turbine bypass line 10 A multiplier 38 for obtaining and outputting 37;
A fourth function generator 40 for obtaining and outputting a low pressure turbine bypass valve flow rate characteristic value 39 based on the reheat steam pressure set value 31 output from the third function generator 32;
The bypass flow rate 37 output from the multiplier 38 is divided by the low pressure turbine bypass valve flow rate characteristic value 39 output from the fourth function generator 40, and the low pressure turbine bypass valve opening lower limit set value 41 is obtained and output. A vessel 42;
The lower one of the low-pressure turbine bypass valve opening lower limit set value 41 output from the divider 42 and the low-pressure turbine bypass valve opening command 35 output from the proportional-plus-integral regulator 36 is selected to select the low-pressure turbine bypass valve opening degree. A high selector 44 to output as a command 43;
A fifth function generator 46 for obtaining and outputting a low-pressure turbine bypass valve opening upper limit set value 45 based on the load command 21;
The lower one of the low-pressure turbine bypass valve opening upper limit set value 45 output from the fifth function generator 46 and the low-pressure turbine bypass valve opening command 43 output from the high selector 44 is selected to select the low-pressure turbine bypass valve. A low selector 47 that outputs to the low-pressure turbine bypass valve 13 as the opening degree command 19 is provided.
[0017]
As shown in FIG. 2, the first function generator 23 is input with a function that increases the main steam pressure set value 22 as the load command 21 increases.
[0018]
As shown in FIG. 3, the second function generator 29 is input with a function for decreasing the high pressure turbine bypass valve opening upper limit set value 28 as the load command 21 increases. The valve opening upper limit set value 28 is set in order to prevent the steam exceeding the allowable allowable capacity of the condenser 7 from being introduced into the condenser 7.
[0019]
As shown in FIG. 4, the third function generator 32 receives a function that increases the reheat steam pressure set value 31 as the load command 21 increases.
[0020]
As shown in FIG. 5, the fourth function generator 40 is input with a function for decreasing the low-pressure turbine bypass valve flow rate characteristic value 39 as the reheat steam pressure set value 31 increases.
[0021]
As shown in FIG. 6, the fifth function generator 46 is input with a function that decreases the low pressure turbine bypass valve opening upper limit set value 45 as the load command 21 increases. The valve opening upper limit set value 45 is set in order to prevent steam exceeding the allowable allowable capacity of the condenser 7 from being introduced into the condenser 7, similar to the high pressure turbine bypass valve opening upper limit set value 28. It is what is done.
[0022]
Next, the operation of the illustrated example will be described.
[0023]
The main steam pressure 14 introduced into the high-pressure turbine 1 is detected by the main steam pressure detector 15, and the reheat steam pressure 16 introduced into the low-pressure turbine 2 is detected by the reheat steam pressure detector 17. 20 is input.
[0024]
In the control device 20, the main steam pressure set value 22 output from the first function generator 23 based on the main steam pressure 14 detected by the main steam pressure detector 15 in the subtractor 25 and the load command 21, and The main steam pressure deviation 24 is output to the proportional-plus-integral controller 27, and the main-steam pressure deviation 24 output from the subtractor 25 is proportional-integrated in the proportional-plus-integral regulator 27. A high-pressure turbine bypass valve opening command 26 for eliminating the pressure deviation 24 is output to the low selector 30, and the high-pressure turbine bypass valve output from the second function generator 29 based on the load command 21 in the low selector 30. The lower one of the opening upper limit set value 28 and the high-pressure turbine bypass valve opening command 26 output from the proportional integral controller 27 is selected and the high-pressure turbine bypass valve opening instruction is selected. 18 is output to the high-pressure turbine bypass valve 11 as the opening adjustment of the high pressure turbine bypass valve 11 is performed.
[0025]
At the same time, the reheat steam pressure 16 detected by the reheat steam pressure detector 17 in the subtractor 34 and the reheat steam pressure set value 31 output from the third function generator 32 based on the load command 21 are obtained. The difference is obtained, and the reheat steam pressure deviation 33 is output to the proportional integration controller 36, and the reheat steam pressure deviation 33 output from the subtractor 34 is proportionally integrated in the proportional integration controller 36. A low pressure turbine bypass valve opening command 35 for eliminating the thermal steam pressure deviation 33 is output to the high selector 44, while the multiplier 38 detects the main steam pressure 14 detected by the main steam pressure detector 15. A high-pressure turbine bypass valve opening command 18 output to the high-pressure turbine bypass valve 11 is applied, and a bypass flow 37 of the main steam flowing into the high-pressure turbine bypass line 10 is obtained. The fourth function generator is configured to output the bypass flow rate 37 output from the multiplier 38 based on the reheat steam pressure set value 31 output from the third function generator 32. The low pressure turbine bypass valve flow rate characteristic value 39 output from 40 is divided, and a low pressure turbine bypass valve opening lower limit set value 41 is obtained and output to the high selector 44. In the high selector 44, the divider 42 The lower one of the low pressure turbine bypass valve opening lower limit set value 41 and the low pressure turbine bypass valve opening command 35 output from the proportional-plus-integral controller 36 is selected, and the lower one is selected as the low pressure turbine bypass valve opening command 43. The low pressure turbine bypass valve opening upper limit output from the fifth function generator 46 based on the load command 21 in the low selector 47 The lower one of the constant value 45 and the low-pressure turbine bypass valve opening command 43 output from the high selector 44 is selected and output to the low-pressure turbine bypass valve 13 as the low-pressure turbine bypass valve opening command 19. Thirteen opening adjustments are made.
[0026]
Here, before the ventilation to the high-pressure turbine 1 and the low-pressure turbine 2 at the start-up of the boiler equipment, the high-pressure turbine bypass valve 11 is opened with the governor valves (not shown) at the inlets of the high-pressure turbine 1 and the low-pressure turbine 2 closed. Even if this is done, since the main steam is introduced into the reheater 5, it takes less time for the boiler to warm up, and the startup time is shortened.
[0027]
Further, by adjusting the opening of the high-pressure turbine bypass valve 11 and adjusting the opening of the low-pressure turbine bypass valve 13, the main steam pressure at the inlet of the high-pressure turbine 1 and the reheat steam pressure at the inlet of the low-pressure turbine 2 basically. In the low selector 30, the high pressure turbine bypass valve opening upper limit set value 28 output from the second function generator 29 based on the load command 21 and the proportional integral controller 27 output. The lower one of the high-pressure turbine bypass valve opening command 26 is selected and output to the high-pressure turbine bypass valve 11 as the high-pressure turbine bypass valve opening command 18, and the low selector 47 uses the fifth command based on the load command 21. Low pressure turbine bypass valve opening upper limit set value 45 output from the function generator 46 and low pressure turbine bypass valve opening output from the high selector 44 Since the lower one of the commands 43 is selected and output to the low-pressure turbine bypass valve 13 as the low-pressure turbine bypass valve opening command 19, steam exceeding the allowable capacity of the condenser 7 is introduced into the condenser 7. Is prevented.
[0028]
Furthermore, the bypass flow rate 37 output from the multiplier 38 to the divider 42 is the flow rate of the main steam flowing into the high pressure turbine bypass line 10, and the bypass flow rate 37 is expressed by a low pressure turbine bypass valve flow rate characteristic value 39. The low pressure turbine bypass valve opening lower limit set value 41 is obtained by dividing, and in the high selector 44, the low pressure turbine bypass valve opening lower limit set value 41 and the low pressure turbine bypass valve output from the proportional integral controller 36 are obtained. Since the higher one of the opening degree commands 35 is selected and outputted to the low selector 47 as the low pressure turbine bypass valve opening degree command 43, at least the same amount as the bypass flow 37 of the main steam flowing into the high pressure turbine bypass line 10 is regenerated. The hot steam flows into the low-pressure turbine bypass line 12, which causes the equipment in the boiler facility to In the case where it is desired to reduce the load suddenly, the main steam released to the high pressure turbine bypass line 10 is released to the low pressure turbine bypass line 12 as the same amount of reheated steam, and the turbine in the conventional example shown in FIG. A bypass function equivalent to the bypass line 8 is ensured. If there is no function of flowing the reheat steam having the same amount as the main steam bypass flow 37 flowing to the high-pressure turbine bypass line 10 to the low-pressure turbine bypass line 12, A part of the steam is supplied to the low-pressure turbine 2 as reheated steam and cannot cope with a rapid load reduction. However, in the case of this illustrated example, it can also cope with a sudden load reduction as described above.
[0029]
Thus, the startup time of the boiler can be shortened, and the main steam pressure at the inlet of the high pressure turbine 1 and the reheat steam pressure at the inlet of the low pressure turbine 2 can be reliably controlled during normal operation. It can cope with sudden load reduction.
[0030]
In addition, the high / low pressure turbine bypass valve control method of the boiler equipment of this invention is not limited only to the above-mentioned illustration example, Of course, it can add various changes within the range which does not deviate from the summary of this invention. .
[0031]
【The invention's effect】
As described above, according to the high and low pressure turbine bypass valve control method for boiler equipment according to the present invention, the startup time of the boiler can be shortened, and the main steam pressure and the low pressure turbine at the inlet of the high pressure turbine can be reduced during normal operation. It is possible to reliably control the reheat steam pressure at the inlet, and to achieve an excellent effect of being able to cope with a sudden load reduction in an emergency.
[Brief description of the drawings]
1 is an overall schematic configuration diagram of an example of an embodiment for carrying out the present invention;
FIG. 2 is a diagram representing a function input to the first function generator shown in FIG. 1;
FIG. 3 is a diagram representing a function input to the second function generator shown in FIG. 1;
FIG. 4 is a diagram representing a function input to the third function generator shown in FIG. 1;
FIG. 5 is a diagram representing a function input to a fourth function generator shown in FIG. 1;
6 is a diagram showing a function input to the fifth function generator shown in FIG. 1; FIG.
FIG. 7 is an overall schematic configuration diagram of a conventional example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 High pressure turbine 2 Low pressure turbine 3 Main steam line 4 Reheat line 5 Reheater 6 Condensate line 7 Condenser 10 High pressure turbine bypass line 11 High pressure turbine bypass valve 12 Low pressure turbine bypass line 13 Low pressure turbine bypass valve 14 Main steam pressure 16 Reheat steam pressure 20 Controller 21 Load command 22 Main steam pressure set value 24 Main steam pressure deviation 26 High pressure turbine bypass valve opening command 28 High pressure turbine bypass valve opening upper limit set value 30 Low selector 31 Reheat steam pressure setting Value 33 Reheat steam pressure deviation 35 Low pressure turbine bypass valve opening command 37 Bypass flow 39 Low pressure turbine bypass valve flow rate characteristic value 41 Low pressure turbine bypass valve opening lower limit set value 44 High selector 45 Low pressure turbine bypass valve opening upper limit set value 47 Low selector

Claims (1)

A high-pressure turbine bypass line that branches off from the middle of the main steam line and is connected in the middle of the reheat line between the high-pressure turbine and the reheater, and in which a high-pressure turbine bypass valve is provided, A boiler facility comprising a low-pressure turbine bypass line that branches off from the middle of the reheat line between and is connected to the middle of the condensate line between the low-pressure turbine and the condenser and provided with a low-pressure turbine bypass valve in the middle A high and low pressure turbine bypass valve control method comprising:
By opening the high-pressure turbine bypass valve opening command to eliminate the main steam pressure deviation between the main steam pressure and the main steam pressure setting value based on the load command, the opening of the high-pressure turbine bypass valve is set to open the high-pressure turbine bypass valve based on the load command. In addition to adjusting within the range not exceeding the upper limit setting value,
The opening of the low-pressure turbine bypass valve is transferred to the high-pressure turbine bypass line according to the low-pressure turbine bypass valve opening command for eliminating the reheat steam pressure deviation between the reheat steam pressure and the reheat steam pressure set value based on the load command. Boiler equipment characterized by adjusting in a range that does not become less than the lower limit setting value of the low-pressure turbine bypass valve opening for securing the bypass flow rate and does not exceed the upper limit setting value of the low-pressure turbine bypass valve opening based on the load command High and low pressure turbine bypass valve control method.

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