CN111664442A - Desuperheating water control method, system and equipment based on heat value calculation and readable storage medium - Google Patents
Desuperheating water control method, system and equipment based on heat value calculation and readable storage medium Download PDFInfo
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- CN111664442A CN111664442A CN202010712047.6A CN202010712047A CN111664442A CN 111664442 A CN111664442 A CN 111664442A CN 202010712047 A CN202010712047 A CN 202010712047A CN 111664442 A CN111664442 A CN 111664442A
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
- F22G5/00—Controlling superheat temperature
- F22G5/12—Controlling superheat temperature by attemperating the superheated steam, e.g. by injected water sprays
- F22G5/123—Water injection apparatus
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F22—STEAM GENERATION
- F22G—SUPERHEATING OF STEAM
- F22G5/00—Controlling superheat temperature
- F22G5/20—Controlling superheat temperature by combined controlling procedures
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- G—PHYSICS
- G05—CONTROLLING; REGULATING
- G05B—CONTROL OR REGULATING SYSTEMS IN GENERAL; FUNCTIONAL ELEMENTS OF SUCH SYSTEMS; MONITORING OR TESTING ARRANGEMENTS FOR SUCH SYSTEMS OR ELEMENTS
- G05B11/00—Automatic controllers
- G05B11/01—Automatic controllers electric
- G05B11/36—Automatic controllers electric with provision for obtaining particular characteristics, e.g. proportional, integral, differential
- G05B11/42—Automatic controllers electric with provision for obtaining particular characteristics, e.g. proportional, integral, differential for obtaining a characteristic which is both proportional and time-dependent, e.g. P.I., P.I.D.
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Abstract
In the process of controlling the flow rate of the desuperheating water, when the actual flow rate of the desuperheating water is low and the precision of a flow measuring device cannot meet the control requirement, the enthalpy value of each fluid in the desuperheating water system under the current working condition is calculated, the theoretical demand of the desuperheating water is calculated according to the heat conservation principle, and when the flow rate of the desuperheating water is high enough and the precision of the flow measuring device meets the control requirement, a cascade PID control system is adopted to control the steam temperature behind a desuperheater; the control of the desuperheating water flow is not a simple control loop adopting a single variable any more, is based on heat conservation and cascade control strategies in the heat exchange process, is applied to the water spraying desuperheating control of a power plant bypass system and the water spraying desuperheating control of an external steam supply desuperheater of a steam extraction heat supply unit, ensures the safe and stable operation of the whole system, and ensures that a process system does not stop due to unqualified steam temperature.
Description
Technical Field
The invention belongs to the technical field of turbine power generation, and relates to a desuperheating water fine control method, a desuperheating water fine control system, desuperheating water fine control equipment and a readable storage medium based on heat value calculation.
Background
Most of steam temperature control systems in the energy and chemical industries adopt a control mode of spraying water to reduce temperature, and a single-loop PID control scheme is usually adopted from the aspect of a control strategy, namely, the opening of a temperature reduction water valve is subjected to positive feedback regulation through an actual measured value of the steam temperature, as shown in figure 7.
The control mode has clear thought and clear strategy, but in practical engineering application, a system needs to arrange a temperature measuring point behind the water spraying temperature reducing device, the measuring point is arranged to be closer to the water spraying temperature reducing device, the response speed of the temperature reducing water regulating valve is high, but the temperature measuring value is easily interfered by the fluctuation of the flow of the temperature reducing water, the steam temperature can not be really reflected, and the stability of the control system is not facilitated; the measuring point is arranged far away from the water spraying temperature reducing device, so that the delay of a control object is large, and the difficulty of steam temperature control is increased; in addition, the temperature control object often has nonlinear characteristics, which further results in poor actual control effect.
Disclosure of Invention
Aiming at the defects in the prior art, the invention provides a desuperheating water fine control method, a desuperheating water fine control system, desuperheating water fine control equipment and a readable storage medium based on heat value calculation.
In order to achieve the purpose, the invention is realized by the following technical scheme: a desuperheating water fine control method based on heat value calculation comprises the following steps:
s1, respectively obtaining pressure and temperature measurement values of front and rear steam and desuperheater water of the desuperheater, and calculating a front steam enthalpy value of the desuperheater, a rear steam enthalpy value of the desuperheater and an enthalpy value of the desuperheater water;
s2, determining the temperature reduction water flow required under the current steam flow according to the steam enthalpy value before the desuperheater, the steam enthalpy value after the desuperheater and the temperature reduction water enthalpy value;
s3, controlling the flow of the desuperheating water by adopting a feedforward and feedback control strategy or a cascade PID control strategy according to the relation between the current desuperheating water flow and a set value obtained in the step S2;
if the flow rate of the desuperheating water is lower than a set value, adopting a feedforward + feedback control strategy to control the flow rate of the desuperheating water;
and if the desuperheating water flow is higher than the set value, adopting a cascade PID control strategy to control the desuperheating water flow.
In step S1, the pressure and temperature signals of the steam and the desuperheater water before and after the desuperheater in the system are filtered, and then the filtered temperature and pressure signals are converted into enthalpy signals of the steam and the desuperheater water before and after the desuperheater through the physical property table of the corresponding medium.
The specific method for obtaining the temperature-reduction water flow required under the current steam flow in the step S2 is as follows:
step S21, subtracting the enthalpy value of the steam after the desuperheater from the enthalpy value of the steam before the desuperheater to obtain the enthalpy value reduction amount of the steam after the steam passes through the desuperheater;
step S22, subtracting the enthalpy value of the desuperheater from the steam enthalpy value of the desuperheater to obtain the enthalpy value increment of the desuperheater after the desuperheater passes through the desuperheater;
step S23, the ratio of the steam enthalpy value reduction amount to the temperature reduction water enthalpy value increase amount is a temperature reduction water flow coefficient;
and step S24, multiplying the temperature-reducing water flow coefficient by the steam flow value to obtain the required temperature-reducing water flow.
The method for controlling the flow of the desuperheating water through the feedforward-feedback control strategy in the step S3 is as follows:
step S311, obtaining a feedforward opening instruction of the desuperheating water valve through a desuperheating water valve characteristic calculation formula according to the desuperheating water flow required by the current working condition and the pressure of the desuperheater in front of and behind the desuperheater;
step S312, calculating the set value and the feedback value of the steam temperature through PID to obtain an opening command of the temperature reduction water valve;
and step S313, superposing the feedforward opening instruction of the desuperheating water valve and the opening instruction of the desuperheating water valve to obtain the actual opening instruction of the desuperheating water valve under the feedforward-feedback working condition.
The method for controlling the flow rate of the desuperheating water through the cascade PID control in the step S3 is as follows:
step S321, the cascade external loop is a temperature control loop, the set value is a steam temperature demand value, and the feedback value is the actual steam temperature;
step S322, the cascade inner loop is a flow control loop, the set value is the sum of the output value of the outer loop and the flow of the desuperheating water required by the current working condition, and the feedback value is the flow of the desuperheating water obtained by actual measurement.
A system of a desuperheating water control method based on heat value calculation comprises a process quantity enthalpy value calculation module, a desuperheating water flow demand calculation module, a desuperheating water temperature feedforward-feedback control module and a desuperheating water temperature cascade control module;
a process enthalpy calculation module: collecting pressure and temperature signals of steam and desuperheater before and after the desuperheater, performing signal processing on the pressure and temperature signals, and inquiring the enthalpy values of the steam and the desuperheater before and after the desuperheater according to the physical property parameter table of corresponding fluid;
a desuperheating water flow demand calculation module: determining theoretical demand of the desuperheating water under the current working condition according to the steam enthalpy value before and after the desuperheating device and the enthalpy value of the desuperheating water, and sending the theoretical demand to a desuperheating water temperature feedforward-feedback control module and a cascade control module;
a reduced temperature water temperature feedforward-feedback control module: adopting a feedforward-feedback control strategy, wherein a feedforward value is the theoretical valve opening under the current working condition, correcting the theoretical valve opening according to a temperature signal, eliminating temperature control deviation, and obtaining the theoretical valve opening under the current working condition according to the theoretical demand of desuperheating water under the current working condition and the front and back pressures of the desuperheating water valve and according to a valve characteristic curve;
temperature reduction water temperature cascade control module: a cascade control strategy is adopted, an inner loop is a flow control loop to accelerate the corresponding speed of the system flow, and an outer loop is a temperature control loop to eliminate temperature control deviation; the set value and the feedback value of the outer loop are respectively a current set value and an actual measured value of the steam temperature; the set value of the inner loop is the sum of the output of the outer loop and the required value of the flow of the temperature-reducing water, and the feedback value is the actual measured value of the flow of the temperature-reducing water.
The desuperheating water flow demand calculation module comprises a first subtraction unit, a second subtraction unit, a division unit and a multiplication unit;
the front steam enthalpy value of the desuperheater and the rear steam enthalpy value of the desuperheater are respectively used as the positive end and the negative end of the first subtraction unit to be input; the steam enthalpy value and the desuperheater enthalpy value behind the desuperheater are respectively used as the positive end and the negative end of the second subtraction unit to be input;
the output of the first subtraction unit is the enthalpy value reduction amount of the steam after passing through the desuperheater, and the output of the second subtraction unit is the enthalpy value increase amount of the desuperheater after passing through the desuperheater;
the output of the first subtraction unit is used as a dividend of the division operation unit, the output of the second subtraction unit is used as a divisor of the division operation unit, and the output of the division unit is a temperature-reduced water flow coefficient;
the desuperheating water flow coefficient and the desuperheater front steam flow are used as the input of a multiplication unit, and the output of the multiplication unit is the desuperheating water flow demand value.
The temperature-reducing water temperature feedforward-feedback control module comprises a third calculation function calculation unit, a PID control unit and a summation calculation unit;
the temperature-reducing water flow demand value, the steam pressure before the temperature reducer and the steam pressure after the temperature reducer are used as the input of a third calculation function calculation unit;
the third calculation function is a calculation formula of the characteristics of the desuperheating water valve;
the output of the third calculation function is a theoretical opening value required by the temperature-reducing water valve to reach the current flow under the current working condition, namely a feedforward value of the temperature-reducing water regulating valve;
the set value of the temperature of the desuperheater and the steam temperature behind the desuperheater are respectively the set value input and the feedback value input of a PID control unit
The output of the PID control unit is a correction value of the temperature-reducing water regulating valve; the feedforward value and the correction value of the desuperheating water regulating valve are calculated by a summation module to obtain an actual valve position instruction of the desuperheating water regulating valve under a low-flow working condition;
the temperature-reducing water temperature cascade control module comprises a first PID control unit, a summation operation unit and a second PID control unit;
the temperature set value of the desuperheater and the steam temperature behind the desuperheater are respectively the set value input and the feedback value input of the first PID control unit;
the output of the first PID control unit is a temperature-reduced water flow correction value which is used for stabilizing the steam temperature at a set value finally and eliminating steady-state deviation;
the temperature-reducing water flow correction value and the temperature-reducing water flow demand value are used as the input of a summation operation unit, and the output of the module is a temperature-reducing water flow set value;
the set value of the second PID control unit is input as a temperature-reducing water flow set value and a temperature-reducing water flow measured value;
the output of the second PID control unit is an actual valve position instruction of the temperature reduction water regulating valve under a high-flow working condition.
A computer device comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing the steps of the desuperheating water control method based on heating value calculation of the present invention when executing the computer program.
A computer-readable storage medium storing a computer program which, when executed by a processor, implements the steps of the desuperheating water control method based on heating value calculation of the present invention.
Compared with the prior art, the invention has the following beneficial technical effects:
according to the fine control method for the desuperheating water based on the heat value calculation, the movement of the louver in the whole sector is realized in a step-by-step movement mode, and in the change process of the operation working condition of the unit, the conventional simultaneous movement of the louver executing mechanism is improved into the sequential movement, so that the simultaneous rate of the movement of the louver executing mechanism is reduced, and the manufacturing cost of a power supply loop of the sector executing mechanism is indirectly reduced; meanwhile, only a single shutter is in an action state at the same time, so that the action amplitude of any shutter in the adjusting process is far larger than that of any shutter in a conventional control mode, the adjusting function of the shutter actuating mechanism is fully exerted, the influence of the dead zone of the actuating mechanism on adjustment is reduced, and the adjusting quality is enhanced.
Drawings
FIG. 1 shows the application of the control method and the measurement requirements of the process in the embodiment of the present invention.
Fig. 2 is an overall structural diagram of a desuperheating water flow control method according to an embodiment of the present invention.
FIG. 3a is a schematic diagram of a method for calculating the enthalpy of steam before a process desuperheater in a control method.
Fig. 3b is a schematic diagram of a method for calculating the enthalpy of steam after a process desuperheater in the control method.
Figure 3c is a schematic diagram of a process quantity desuperheating water enthalpy value calculation method in the control method.
FIG. 4 is a schematic diagram of a method for calculating a demand value for flow of chilled water in a control method.
Fig. 5 is a diagram showing a feedforward-feedback control structure at a low flow rate in the control method.
Fig. 6 is a diagram showing a configuration of cascade control at high flow rate in the control method.
FIG. 7 is a schematic view of a conventional method for controlling the flow rate of desuperheated water.
Detailed Description
The present invention will now be described in further detail with reference to the attached drawings, which are illustrative, but not limiting, of the present invention.
Referring to fig. 1, a fine control method of desuperheating water based on heat value calculation is applied to the following occasions:
one path of desuperheating water is desuperheated to steam through a desuperheating device, and a desuperheating water isolation valve and a desuperheating water adjusting valve are arranged on a desuperheating water pipeline along the flow direction of a medium.
Variables such as temperature and pressure of each fluid in the system are detected.
Specifically, the pressure, the temperature and the flow of the desuperheating water on the desuperheating water pipeline are detected;
the front and rear steam pipelines of the desuperheater should detect the pressure and temperature of the front and rear steam pipelines.
Referring to fig. 2, as an example, a desuperheating water fine control method based on a heating value calculation includes the steps of:
s1, acquiring a process variable in the system: and acquiring front and rear steam of the desuperheater, the temperature and pressure signals of the desuperheater, and converting the signals into corresponding enthalpy values through a process quantity enthalpy value calculation module.
And S2, converting the enthalpy value and the measured steam flow value of each working medium in the system into a temperature-reducing water flow demand value under the current working condition through a temperature-reducing water flow demand calculation module.
And S3, inputting the demand value of the flow of the desuperheater, the pressure before and after the desuperheater, the set value of the steam temperature and the feedback value into a feedforward-feedback control module, and calculating a valve position instruction at the time of low flow.
And S4, inputting the temperature-reduced water flow demand value, the steam flow measured value, the steam temperature set value and the feedback value into the cascade control module, and calculating a valve position instruction at high flow.
And S5, inputting a valve position instruction in low flow and a valve position instruction in high flow into a switching module, and switching according to a low signal of the temperature-reduced water flow.
Specifically, the measured value of the desuperheating water flow is compared and judged with a fixed value, when the measured value of the desuperheating water flow is lower than the fixed value, the comparison module outputs a digital quantity 1, otherwise, the digital quantity 0 is output, and the output of the comparison module is a low flow signal.
The constant value is the lower limit of the flow value which can be accurately measured by the desuperheating water flow measuring device, and the constant value is obtained through experiment or simulation in the production and design process of the flow measuring device and is provided by a flow measuring device manufacturer.
S6, switching two paths of the switching module inputs a valve position instruction at low flow and a valve position instruction at high flow, when the flow low signal is 1, the switching module outputs the valve position instruction at low flow, otherwise, the switching module outputs the valve position instruction at high flow.
Referring to fig. 3a, 3b and 3c, after obtaining the temperature and pressure signals of the front and rear steam and the temperature and pressure signals of the desuperheater, firstly, filtering the signals, and converting the temperature and pressure signals of the front and rear steam of the desuperheater into enthalpy values of the front and rear steam of the desuperheater through a first conversion function; and converting the pressure and the temperature of the desuperheating water into the enthalpy value of the desuperheating water through a second conversion function.
The first refraction function is a steam enthalpy curve and is obtained through a steam physical property parameter table.
The second calculation function is a water enthalpy value curve and is obtained through a water physical parameter table.
Referring to fig. 4, the reducing water flow rate demand calculation module includes a first subtraction unit, a second subtraction unit, a division unit, and a multiplication unit.
The front steam enthalpy value of the desuperheater and the rear steam enthalpy value of the desuperheater are respectively used as the positive end and the negative end of the first subtraction unit to be input; and the steam enthalpy value and the desuperheater enthalpy value after the desuperheater are respectively used as the positive end and the negative end of the second subtraction unit for input.
The output of the first subtraction unit is the enthalpy value reduction amount of the steam after passing through the desuperheater, and the output of the second subtraction unit is the enthalpy value increase amount of the desuperheater after passing through the desuperheater.
The output of the first subtraction unit is used as the dividend of the division operation unit, the output of the second subtraction unit is used as the divisor of the division operation unit, and the output of the division unit is the temperature-reduced water flow coefficient.
The desuperheating water flow coefficient and the desuperheater front steam flow are used as the input of a multiplication unit, and the output of the multiplication unit is the desuperheating water flow demand value.
Referring to fig. 5, the desuperheating water temperature feedforward-feedback control module generates a valve position instruction at low flow, and includes a third folding calculation function calculation unit, a PID control unit, and a summation calculation unit.
The desuperheating water flow demand value, the desuperheater front steam pressure and the desuperheater rear steam pressure are used as the input of the third calculation function calculation unit.
The third calculation function is a calculation formula of the characteristics of the desuperheating water valve, which is obtained by the manufacturer of the desuperheating water valve through experiment or simulation calculation when the valve is designed and is provided by the manufacturer of the valve.
The output of the third calculation function is a theoretical opening value required by the temperature-reducing water valve to reach the current flow under the current working condition, namely a feedforward value of the temperature-reducing water regulating valve.
The set value of the temperature of the desuperheater and the temperature of steam behind the desuperheater are respectively the set value input and the feedback value input of the PID control unit.
The PID control unit outputs a correction value of the temperature-reducing water regulating valve, and the correction value has the function of finally stabilizing the steam temperature at a set value and eliminating steady-state deviation.
And the actual valve position instruction of the temperature-reducing water regulating valve under the low-flow working condition is obtained after the feedforward value and the correction value of the temperature-reducing water regulating valve are calculated by the summation module.
Referring to fig. 6, the desuperheating water temperature cascade control module generates a valve position instruction at high flow, and includes a first PID control unit, a summation operation unit, and a second PID control unit.
The set value of the temperature of the desuperheater and the temperature of steam behind the desuperheater are respectively input as a set value and a feedback value of the first PID control unit.
The output of the first PID control unit is a temperature-reduced water flow correction value which has the function of finally stabilizing the steam temperature at a set value and eliminating steady-state deviation.
The temperature-reducing water flow correction value and the temperature-reducing water flow demand value are used as the input of the summation operation unit, and the output of the module is a temperature-reducing water flow set value.
The set value of the second PID control unit is input as a temperature-reducing water flow set value and a temperature-reducing water flow measured value.
The output of the second PID control unit is an actual valve position instruction of the temperature reduction water regulating valve under a high-flow working condition, and the actual valve position instruction is used for increasing the response speed of the whole loop in a mode of accelerating the flow response speed.
A fine control method of desuperheating water based on heat value calculation implements subsection control to a desuperheating water regulating valve:
when the actual flow of the desuperheating water is low and the precision of the flow measuring device cannot meet the control requirement, the enthalpy value of each fluid in the desuperheating water system under the current working condition is calculated, and the theoretical demand of the desuperheating water is calculated according to the heat conservation principle. And further, on the basis of the theoretical demand of the desuperheating water, the steam temperature is finely adjusted through the current steam temperature so as to overcome the uncertain disturbance in the system.
When the flow of the desuperheated water is high enough and the precision of the flow measuring device meets the control requirement, a cascade PID control system is adopted to control the temperature of the steam behind the desuperheater. The inner loop adopts flow control to improve the response speed of the control system; the outer loop adopts temperature control to realize fine adjustment of final temperature, eliminate steady state deviation of temperature control and ensure control precision.
After the method is adopted, the flow control of the desuperheating water is not a simple control loop adopting a single variable, but a set of systematic control strategy based on heat conservation and cascade control in the heat exchange process and comprehensively considering the influence of the confidence interval of a measuring instrument and the disturbance of the external desuperheating water flow on the control.
The method can be directly applied to the water spraying temperature reduction control of a power plant bypass system and the water spraying temperature reduction control of an external steam supply temperature reducer of a steam extraction and heat supply unit, the control rapidity and accuracy ensure the safe and stable operation of the whole system, and the non-stop of a process system caused by unqualified steam temperature is ensured. Meanwhile, after the method is used, the temperature of the steam behind the desuperheater can be accurately controlled, the steam temperature with stable quality is provided for users, and the economic benefit is improved.
According to the fine control method for the desuperheating water based on the heat value calculation, the cascade control strategy is introduced into the desuperheating water flow control, so that the control accuracy is ensured, and the overall response speed is improved; furthermore, in consideration of the problem that the precision of the desuperheating water flow measuring device is difficult to guarantee under the low-flow working condition, an enthalpy value control strategy based on heat balance is adopted under the low-flow working condition, the desuperheating water flow required by the current working condition theory is calculated, and the theoretical value is finely adjusted through the steam temperature.
The method provided by the invention not only has the characteristics of quick response and accurate control of the cascade control system, but also ensures the final control effect by combining the theoretical analysis of heat value calculation. The achievement can be directly applied to the water spraying temperature reduction control of a bypass system of a power plant and the water spraying temperature reduction control of an external steam supply temperature reducer of a steam extraction heat supply unit, and the safety and the stability of the whole system are ensured by the rapidity and the accuracy of the control.
The invention discloses a desuperheating water control system based on heat value calculation, which comprises a desuperheating water flow demand calculation module, a desuperheating water valve opening calculation module and a desuperheating water temperature cascade control module. When the flow is low, the flow of the desuperheating water is controlled according to the calculation of the heat value, so that the influence of lower precision of a flow measuring device under the working condition of low flow on the control is avoided; and cascade control is adopted at high flow, so that the response speed of the system is increased while the accuracy is ensured. The invention increases the adjusting quality of the temperature-reducing water flow control from the angle of the control strategy.
A process enthalpy calculation module: collecting pressure and temperature signals of steam and desuperheater before and after the desuperheater, performing signal processing on the pressure and temperature signals, and inquiring the enthalpy values of the steam and the desuperheater before and after the desuperheater according to the physical property parameter table of corresponding fluid;
a desuperheating water flow demand calculation module: determining theoretical demand of the desuperheating water under the current working condition according to the steam enthalpy value before and after the desuperheating device and the enthalpy value of the desuperheating water, and sending the theoretical demand to a desuperheating water temperature feedforward-feedback control module and a cascade control module;
a reduced temperature water temperature feedforward-feedback control module: adopting a feedforward-feedback control strategy, wherein a feedforward value is the theoretical valve opening under the current working condition, correcting the theoretical valve opening according to a temperature signal, eliminating temperature control deviation, and obtaining the theoretical valve opening under the current working condition according to the theoretical demand of desuperheating water under the current working condition and the front and back pressures of the desuperheating water valve and according to a valve characteristic curve;
the temperature-reducing water temperature feedforward-feedback control module comprises a third calculation function calculation unit, a PID control unit and a summation calculation unit;
the temperature-reducing water flow demand value, the steam pressure before the temperature reducer and the steam pressure after the temperature reducer are used as the input of a third calculation function calculation unit;
the third calculation function is a calculation formula of the characteristics of the desuperheating water valve;
the output of the third calculation function is a theoretical opening value required by the temperature-reducing water valve to reach the current flow under the current working condition, namely a feedforward value of the temperature-reducing water regulating valve;
the set value of the temperature of the desuperheater and the steam temperature behind the desuperheater are respectively the set value input and the feedback value input of a PID control unit
The output of the PID control unit is a correction value of the temperature-reducing water regulating valve; the feedforward value and the correction value of the desuperheating water regulating valve are calculated by a summation module to obtain an actual valve position instruction of the desuperheating water regulating valve under a low-flow working condition;
temperature reduction water temperature cascade control module: a cascade control strategy is adopted, an inner loop is a flow control loop to accelerate the corresponding speed of the system flow, and an outer loop is a temperature control loop to eliminate temperature control deviation; the set value and the feedback value of the outer loop are respectively a current set value and an actual measured value of the steam temperature; the set value of the inner loop is the sum of the output of the outer loop and the required value of the flow of the desuperheating water, and the feedback value is the actual measured value of the flow of the desuperheating water;
the temperature-reducing water temperature cascade control module comprises a first PID control unit, a summation operation unit and a second PID control unit;
the temperature set value of the desuperheater and the steam temperature behind the desuperheater are respectively the set value input and the feedback value input of the first PID control unit;
the output of the first PID control unit is a temperature-reduced water flow correction value which is used for stabilizing the steam temperature at a set value finally and eliminating steady-state deviation;
the temperature-reducing water flow correction value and the temperature-reducing water flow demand value are used as the input of a summation operation unit, and the output of the module is a temperature-reducing water flow set value;
the set value of the second PID control unit is input as a temperature-reducing water flow set value and a temperature-reducing water flow measured value;
the output of the second PID control unit is an actual valve position instruction of the temperature reduction water regulating valve under a high-flow working condition.
The desuperheating water control system based on heat value calculation is more suitable for large thermal power generating units and can be realized by DCS control system configurations designed and produced by different companies; in order to facilitate implementation, signals such as the measured values, the set values and the valve instructions of the process variables in the example are all from a DCS (distributed control System) of the thermal generator set.
The invention also provides computer equipment comprising a memory, a processor and a computer program stored in the memory and capable of running on the processor, wherein the processor executes the computer program to realize the steps of the desuperheating water control method based on heat value calculation.
The desuperheating water control method of the present invention based on heating value calculation may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present invention may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein. The desuperheating water control method based on heat value calculation of the present invention may be stored in a computer-readable storage medium if it is implemented in the form of a software functional unit and sold or used as an independent product.
Based on such understanding, in the exemplary embodiment, a computer readable storage medium is also provided, all or part of the processes in the method of the above embodiments of the present invention can be realized by a computer program to instruct related hardware, the computer program can be stored in the computer readable storage medium, and when the computer program is executed by a processor, the steps of the above method embodiments can be realized. Wherein the computer program comprises computer program code, which may be in the form of source code, object code, an executable file or some intermediate form, etc. Computer-readable storage media, including both non-transitory and non-transitory, removable and non-removable media, may implement information storage by any method or technology. The information may be computer readable instructions, data structures, modules of a program, or other data. It should be noted that the computer readable medium may contain content that is subject to appropriate increase or decrease as required by legislation and patent practice in jurisdictions, for example, in some jurisdictions, computer readable media does not include electrical carrier signals and telecommunications signals as is required by legislation and patent practice. The computer storage medium may be any available medium or data storage device that can be accessed by a computer, including but not limited to magnetic memory (e.g., floppy disk, hard disk, magnetic tape, magneto-optical disk (MO), etc.), optical memory (e.g., CD, DVD, BD, HVD, etc.), and semiconductor memory (e.g., ROM, EPROM, EEPROM, nonvolatile memory (NANDFLASH), Solid State Disk (SSD)), etc.
In an exemplary embodiment, a computer device is also provided, comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor implementing the steps of the desuperheating water control method based on heating value calculation when executing the computer program. The processor may be a Central Processing Unit (CPU), other general purpose processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), an off-the-shelf programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, etc.
The above-mentioned contents are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modification made on the basis of the technical idea of the present invention falls within the protection scope of the claims of the present invention.
Claims (10)
1. A desuperheating water fine control method based on heat value calculation is characterized by comprising the following steps:
s1, respectively obtaining pressure and temperature measurement values of front and rear steam and desuperheater water of the desuperheater, and calculating a front steam enthalpy value of the desuperheater, a rear steam enthalpy value of the desuperheater and an enthalpy value of the desuperheater water;
s2, determining the required desuperheating water flow under the current steam flow according to the obtained desuperheater front steam enthalpy value, desuperheater rear steam enthalpy value and desuperheating water enthalpy value in S1;
s3, controlling the flow of the desuperheating water by adopting a feedforward and feedback control strategy or a cascade PID control strategy according to the relation between the current desuperheating water flow and a set value obtained in the step S2;
if the flow of the desuperheating water is lower than the set value, adopting a feedforward-feedback control strategy to control the flow of the desuperheating water;
and if the desuperheating water flow is higher than the set value, adopting a cascade PID control strategy to control the desuperheating water flow.
2. The desuperheating water control method based on heating value calculation as claimed in claim 1, wherein the pressure and temperature signals of the steam and desuperheating water before and after the desuperheater in the system are filtered at step S1, and then the filtered temperature and pressure signals are converted into enthalpy signals of the steam and desuperheater before and after the desuperheater through the physical property table of the corresponding medium.
3. A desuperheating water control method based on heat value calculation as claimed in claim 1, wherein the specific method of obtaining the required desuperheating water flow at the current steam flow in step S2 is as follows:
step S21, subtracting the enthalpy value of the steam after the desuperheater from the enthalpy value of the steam before the desuperheater to obtain the enthalpy value reduction amount of the steam after the steam passes through the desuperheater;
step S22, subtracting the enthalpy value of the desuperheater from the steam enthalpy value of the desuperheater to obtain the enthalpy value increment of the desuperheater after the desuperheater passes through the desuperheater;
step S23, the ratio of the steam enthalpy value reduction amount to the temperature reduction water enthalpy value increase amount is a temperature reduction water flow coefficient;
and step S24, multiplying the temperature-reducing water flow coefficient by the steam flow value to obtain the required temperature-reducing water flow.
4. The desuperheating water control method based on heat value calculation as claimed in claim 1, wherein the method of controlling the flow rate of desuperheating water by the feedforward-feedback control strategy in step S3 is as follows:
step S311, obtaining a feedforward opening instruction of the desuperheating water valve through a desuperheating water valve characteristic calculation formula according to the desuperheating water flow required by the current working condition and the pressure of the desuperheater in front of and behind the desuperheater;
step S312, calculating the set value and the feedback value of the steam temperature through PID to obtain an opening command of the temperature reduction water valve;
and step S313, superposing the feedforward opening instruction of the desuperheating water valve and the opening instruction of the desuperheating water valve to obtain the actual opening instruction of the desuperheating water valve under the feedforward-feedback working condition.
5. The desuperheating water control method based on heat value calculation as claimed in claim 1, wherein the method of controlling the flow rate of desuperheating water by cascade PID control in step S3 is as follows:
step S321, the cascade external loop is a temperature control loop, the set value is a steam temperature demand value, and the feedback value is the actual steam temperature;
step S322, the cascade inner loop is a flow control loop, the set value is the sum of the output value of the outer loop and the flow of the desuperheating water required by the current working condition, and the feedback value is the flow of the desuperheating water obtained by actual measurement.
6. The system of the desuperheating water control method based on heat value calculation according to any one of claims 1-5, characterized by comprising a process quantity enthalpy value calculation module, a desuperheating water flow demand calculation module, a desuperheating water temperature feedforward-feedback control module and a desuperheating water temperature cascade control module;
a process enthalpy calculation module: collecting pressure and temperature signals of steam and desuperheater before and after the desuperheater, performing signal processing on the pressure and temperature signals, and inquiring the enthalpy values of the steam and the desuperheater before and after the desuperheater according to the physical property parameter table of corresponding fluid;
a desuperheating water flow demand calculation module: determining theoretical demand of the desuperheating water under the current working condition according to the steam enthalpy value before and after the desuperheating device and the enthalpy value of the desuperheating water, and sending the theoretical demand to a desuperheating water temperature feedforward-feedback control module and a cascade control module;
a reduced temperature water temperature feedforward-feedback control module: adopting a feedforward-feedback control strategy, wherein a feedforward value is the theoretical valve opening under the current working condition, correcting the theoretical valve opening according to a temperature signal, eliminating temperature control deviation, and obtaining the theoretical valve opening under the current working condition according to the theoretical demand of desuperheating water under the current working condition and the front and back pressures of the desuperheating water valve and according to a valve characteristic curve;
temperature reduction water temperature cascade control module: a cascade control strategy is adopted, an inner loop is a flow control loop to accelerate the corresponding speed of the system flow, and an outer loop is a temperature control loop to eliminate temperature control deviation; the set value and the feedback value of the outer loop are respectively a current set value and an actual measured value of the steam temperature; the set value of the inner loop is the sum of the output of the outer loop and the required value of the flow of the temperature-reducing water, and the feedback value is the actual measured value of the flow of the temperature-reducing water.
7. The system of a desuperheating water control method based on heat value calculation according to claim 6, wherein the desuperheating water flow demand calculation module comprises a first subtraction unit, a second subtraction unit, a division unit and a multiplication unit;
the front steam enthalpy value of the desuperheater and the rear steam enthalpy value of the desuperheater are respectively used as the positive end and the negative end of the first subtraction unit to be input; the steam enthalpy value and the desuperheater enthalpy value behind the desuperheater are respectively used as the positive end and the negative end of the second subtraction unit to be input;
the output of the first subtraction unit is the enthalpy value reduction amount of the steam after passing through the desuperheater, and the output of the second subtraction unit is the enthalpy value increase amount of the desuperheater after passing through the desuperheater;
the output of the first subtraction unit is used as a dividend of the division operation unit, the output of the second subtraction unit is used as a divisor of the division operation unit, and the output of the division unit is a temperature-reduced water flow coefficient;
the desuperheating water flow coefficient and the desuperheater front steam flow are used as the input of a multiplication unit, and the output of the multiplication unit is the desuperheating water flow demand value.
8. The system of a desuperheating water control method based on heating value calculation according to claim 6, wherein the desuperheating water temperature feedforward-feedback control module includes a third folding calculation function calculation unit, a PID control unit, and a summation calculation unit;
the temperature-reducing water flow demand value, the steam pressure before the temperature reducer and the steam pressure after the temperature reducer are used as the input of a third calculation function calculation unit;
the third calculation function is a calculation formula of the characteristics of the desuperheating water valve;
the output of the third calculation function is a theoretical opening value required by the temperature-reducing water valve to reach the current flow under the current working condition, namely a feedforward value of the temperature-reducing water regulating valve;
the temperature set value of the desuperheater and the steam temperature behind the desuperheater are respectively input as a set value of a PID control unit and a feedback value of the PID control unit and are output as a correction value of a desuperheating water regulating valve; the feedforward value and the correction value of the desuperheating water regulating valve are calculated by a summation module to obtain an actual valve position instruction of the desuperheating water regulating valve under a low-flow working condition;
the temperature-reducing water temperature cascade control module comprises a first PID control unit, a summation operation unit and a second PID control unit;
the temperature set value of the desuperheater and the steam temperature behind the desuperheater are respectively the set value input and the feedback value input of the first PID control unit;
the output of the first PID control unit is a temperature-reduced water flow correction value which is used for stabilizing the steam temperature at a set value finally and eliminating steady-state deviation;
the temperature-reducing water flow correction value and the temperature-reducing water flow demand value are used as the input of a summation operation unit, and the output of the module is a temperature-reducing water flow set value;
the set value of the second PID control unit is input as a temperature-reducing water flow set value and a temperature-reducing water flow measured value;
the output of the second PID control unit is an actual valve position instruction of the temperature reduction water regulating valve under a high-flow working condition.
9. A computer arrangement comprising a memory, a processor and a computer program stored in the memory and executable on the processor, the processor when executing the computer program implementing the steps of the desuperheating water control method based on heating value calculation according to any one of claims 1 to 5.
10. A computer-readable storage medium storing a computer program, wherein the computer program, when executed by a processor, implements the steps of the desuperheating water control method based on heating value calculation according to any one of claims 1 to 5.
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Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112432157A (en) * | 2020-11-18 | 2021-03-02 | 哈尔滨锅炉厂有限责任公司 | Method for monitoring vaporization degree of desuperheating water |
| CN113189861A (en) * | 2021-04-27 | 2021-07-30 | 国能南京电力试验研究有限公司 | Design method of main steam temperature control system equivalent to post-desuperheater temperature control |
| CN113266817A (en) * | 2021-05-25 | 2021-08-17 | 华能东莞燃机热电有限责任公司 | Method for preventing and controlling overtemperature of superheater tube wall |
| CN114797481A (en) * | 2022-04-28 | 2022-07-29 | 华能威海发电有限责任公司 | Double-fed temperature regulating system and method for heating reverse osmosis membrane chemical cleaning steam-water |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108386829A (en) * | 2018-03-01 | 2018-08-10 | 北京德普新源科技发展有限公司 | A kind of temprature control method of boiler overheating steam, device and system |
| CN110631002A (en) * | 2019-09-30 | 2019-12-31 | 大唐郓城发电有限公司 | Control method for main air temperature of thermal power generating unit |
| CN111123770A (en) * | 2019-12-13 | 2020-05-08 | 山东中实易通集团有限公司 | Method and device for determining opening of bypass model under FCB working condition |
-
2020
- 2020-07-22 CN CN202010712047.6A patent/CN111664442B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN108386829A (en) * | 2018-03-01 | 2018-08-10 | 北京德普新源科技发展有限公司 | A kind of temprature control method of boiler overheating steam, device and system |
| CN110631002A (en) * | 2019-09-30 | 2019-12-31 | 大唐郓城发电有限公司 | Control method for main air temperature of thermal power generating unit |
| CN111123770A (en) * | 2019-12-13 | 2020-05-08 | 山东中实易通集团有限公司 | Method and device for determining opening of bypass model under FCB working condition |
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112432157A (en) * | 2020-11-18 | 2021-03-02 | 哈尔滨锅炉厂有限责任公司 | Method for monitoring vaporization degree of desuperheating water |
| CN112432157B (en) * | 2020-11-18 | 2022-12-06 | 哈尔滨锅炉厂有限责任公司 | Method for monitoring vaporization degree of desuperheating water |
| CN113189861A (en) * | 2021-04-27 | 2021-07-30 | 国能南京电力试验研究有限公司 | Design method of main steam temperature control system equivalent to post-desuperheater temperature control |
| CN113266817A (en) * | 2021-05-25 | 2021-08-17 | 华能东莞燃机热电有限责任公司 | Method for preventing and controlling overtemperature of superheater tube wall |
| CN113266817B (en) * | 2021-05-25 | 2022-08-05 | 华能东莞燃机热电有限责任公司 | Method for preventing and controlling overtemperature of superheater tube wall |
| CN114797481A (en) * | 2022-04-28 | 2022-07-29 | 华能威海发电有限责任公司 | Double-fed temperature regulating system and method for heating reverse osmosis membrane chemical cleaning steam-water |
| CN114797481B (en) * | 2022-04-28 | 2023-08-15 | 华能威海发电有限责任公司 | Double-fed temperature regulating system and method for heating reverse osmosis membrane chemical cleaning steam-water |
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