CN115445753B - One-key automatic warm grinding control method for coal-fired unit - Google Patents
One-key automatic warm grinding control method for coal-fired unit Download PDFInfo
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- CN115445753B CN115445753B CN202211108462.6A CN202211108462A CN115445753B CN 115445753 B CN115445753 B CN 115445753B CN 202211108462 A CN202211108462 A CN 202211108462A CN 115445753 B CN115445753 B CN 115445753B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C25/00—Control arrangements specially adapted for crushing or disintegrating
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
- B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
- B02C23/00—Auxiliary methods or auxiliary devices or accessories specially adapted for crushing or disintegrating not provided for in preceding groups or not specially adapted to apparatus covered by a single preceding group
- B02C23/18—Adding fluid, other than for crushing or disintegrating by fluid energy
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23K—FEEDING FUEL TO COMBUSTION APPARATUS
- F23K1/00—Preparation of lump or pulverulent fuel in readiness for delivery to combustion apparatus
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
- F25D29/00—Arrangement or mounting of control or safety devices
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25D—REFRIGERATORS; COLD ROOMS; ICE-BOXES; COOLING OR FREEZING APPARATUS NOT OTHERWISE PROVIDED FOR
- F25D31/00—Other cooling or freezing apparatus
- F25D31/005—Combined cooling and heating devices
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E20/00—Combustion technologies with mitigation potential
- Y02E20/34—Indirect CO2mitigation, i.e. by acting on non CO2directly related matters of the process, e.g. pre-heating or heat recovery
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P90/00—Enabling technologies with a potential contribution to greenhouse gas [GHG] emissions mitigation
- Y02P90/02—Total factory control, e.g. smart factories, flexible manufacturing systems [FMS] or integrated manufacturing systems [IMS]
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- Physics & Mathematics (AREA)
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- Crushing And Grinding (AREA)
- Disintegrating Or Milling (AREA)
Abstract
The invention discloses a one-key automatic warm grinding control method for a coal-fired unit. The problem of inaccurate small flow measurement exists in most coal mill primary air flows in the warm grinding period of the coal-fired unit provided with the medium-speed direct-fired pulverizing system, so that the cold and hot air regulating doors of the coal mill in the warm grinding period of the grinding unit cannot be automatically regulated in a closed loop, and the automation degree of the warm grinding of the grinding unit is seriously restricted. According to the invention, the average coal quantity of the grinding group is calculated according to the real-time operation parameters of the current pulverizing system of the unit, the load capacity of the residual quantity of the current grinding group is calculated by combining the dynamic coal quantity pre-estimated value and the upper limit of the coal quantity of the grinding group, the sliding time window generated based on the statistical grinding group warm grinding starting time sequence is taken as a boundary condition, the grinding group warm grinding time is predicted, and meanwhile, the optimal sequencing of the grinding group warm grinding starting sequence is carried out by combining the conditions of grinding group arrangement, grinding group operation switching rules, grinding group maintenance or fault and the like, the grinding group warm grinding starting instruction is automatically sent, the warm grinding starting sequential control function group is called, and the grinding group warm grinding is automatically completed.
Description
Technical Field
The invention belongs to the field of automatic control and intelligent control, and particularly relates to a one-key automatic warm grinding control method suitable for a coal-fired unit provided with a medium-speed direct-fired pulverizing system.
Background
The coal pulverizing system is an important auxiliary machine system of a combustion control system of the coal-fired unit, the coal pulverizing system of the large ultra-supercritical unit is generally provided with 6 sets of grinding sets, and main equipment of each set of grinding set of the coal-fired unit provided with the medium-speed direct-fired coal pulverizing system comprises a coal mill oil pump, a coal feeder, a coal mill, related air doors and the like. The running number and the output of the grinding groups in the pulverizing system are synchronous with the load of the unit in real time, and the grinding groups are started and stopped in time according to the increase and decrease of the load of the unit. With the rapid transformation of the energy structure in China, the peak regulation capacity of the basic energy power taking the coal-fired power generation as the main body directly determines the development space of renewable energy sources such as wind power, solar power generation and the like, and a large amount of intermittent energy power grid connection can force the coal-fired power generator set to participate in deep peak regulation comprehensively and deeply, the deep peak regulation of the coal-fired power generator set is normalized, and the start-stop frequency of the mill set is increased continuously. As an important direction of intelligent development of a thermal power generating set, a set automatic start-stop control system (automatic power plant start-up and shutdown-down system, APS) is developed and practiced for many years, the design concept and the operation mode of the set automatic start-stop control system are gradually approved by the power generation industry and are gradually applied to a control system of a large-scale power plant, and a powder making system is used as a system with relatively independent functions, so that the APS function of the powder making system can be completely designed, and one-key automatic start-stop control of the powder making system is completed.
In the starting process of the mill group, the warm mill of the coal mill can be safely, quickly and flexibly completed, so that the outlet temperature of the coal mill reaches the requirement, and the warm mill is a key technical problem for limiting the practicability of the starting functional group of the powder preparation system. The coal pulverizing system needs to perform warm grinding on the coal mill once every time, related air doors are required to be operated in sequence in the warm grinding process, the opening degree of the mill cooling and hot air regulating doors are required to be adjusted in real time, parameters such as the outlet temperature, the primary air flow and the inlet air pressure of the coal mill are also required to be maintained in a certain range, at present, the domestic coal-fired unit mostly adopts a control strategy of manual operation of an operator facing complex and repeated warm grinding operation, time is wasted, and the operation burden of the operator is greatly increased. In addition, in the running process of the unit, due to lack of accurate prediction of the load of the unit, operators can only manually determine the warm grinding time of the coal mill according to the unit states such as the output force of the coal pulverizing system, the target load change trend and the like, the warm grinding time is not properly selected, the starting of the coal pulverizing system is directly affected, and then the load capacity of the unit and the station service power index are related.
The problem of inaccurate small flow measurement exists in most coal mill primary air flows in the warm grinding period of the coal-fired unit provided with the medium-speed direct-fired pulverizing system, so that the cold and hot air regulating doors of the coal mill in the warm grinding period of the grinding unit cannot be automatically regulated in a closed loop, and the automation degree of the warm grinding of the grinding unit is seriously restricted.
Disclosure of Invention
The invention aims to solve the technical problems of overcoming the defects in the prior art, and provides a one-key automatic warm mill control method of a coal-fired unit, which is suitable for configuring a medium-speed direct-fired pulverizing system, optimally sequences the start sequence of warm mills of a mill group, automatically sends out a start command of the warm mills of the mill group, and calls a sequential control function group for starting the warm mills to automatically finish the warm mills of the mill group.
The invention adopts the technical scheme that: a one-key automatic warm grinding control method of a coal-fired unit comprises the following steps:
step 1, judging whether a grinding group one-key automatic warm grinding function is put into operation, if yes, carrying out step 2, and if not, waiting in step 1;
step 2, calling a grinding set warm mill starting time model;
step 3, calling a grinding group warm mill starting sequence model according to the grinding group warm mill starting time model;
step 4, outputting a grinding group warm mill starting instruction according to the grinding group warm mill starting time model and the grinding group warm mill starting sequence model;
and 5, calling a warm mill start sequence control function group according to a mill group warm mill start instruction.
Further, the specific content of step 2 is as follows:
firstly, calculating to obtain the average coal quantity of an operation grinding group according to the current total coal quantity, the number of the operation grinding groups and the coal feeding bias of the unit, and simultaneously calculating to obtain the variable load feedforward of the boiler of the unit if the unit is subjected to 10 MW-20 MW load increase through the AGC rate of the unit, and estimating the dynamic coal quantity; then, combining the upper limit of the coal quantity of the grinding group to obtain the residual load capacity of the unit under the current grinding group; and finally, predicting the start time of the warm mill group by taking a sliding time window generated by the warm mill start time sequence of the warm mill group based on statistics as a boundary condition.
Further, the specific content of step 3 is as follows: and generating a grinding set operation switching rule through the arrangement of the unit grinding sets, comprehensively considering the running states of the grinding sets, and optimally sequencing the warm grinding start sequence of the grinding sets.
Further, step 5, the detailed steps of the coal-fired unit warm grinding start sequential control function group for configuring the medium-speed direct-fired pulverizing system are as follows:
5.1, opening an electric flashboard door at the outlet of the coal feeder, closing an outlet pneumatic valve of a pebble coal box of the coal mill, and opening an inlet pneumatic valve of the pebble coal box of the coal mill;
5.2, opening an electric plugboard door at the inlet of the coal feeder and a sealing wind power baffle of the coal mill;
5.3, opening a pneumatic flashboard door of an outlet of the coal mill;
5.4, opening a cold and hot primary air pneumatic plugboard door of the coal mill;
5.5, calling a whole-process control module for cold and hot air door adjustment and warm grinding of the coal mill: the control of cold and hot air regulating doors of the coal mill is divided into a cold air door valve-fixing mode, a cold air door climbing boosting mode, a hot air door valve-fixing mode and a hot air door climbing heating mode, 4 modes are flexibly scheduled under the cold state and hot state working conditions of grinding groups, and the rate self-adaptive warm grinding control is automatically completed.
Further, the forming process of the statistical grinding group warm grinding starting time sequence is as follows:
and establishing a plurality of sliding time windows when the running number of the grinding groups is increased by utilizing a historical data set of the unit pulverizing system, wherein each sliding time window takes the moment when the pneumatic plugboard door at the outlet of the coal mill and the cold and hot primary air pneumatic plugboard door of the coal mill are in an open state as the initial representation of the sliding time window, the moment when the coal mill is started as the ending representation of the sliding time window, the time difference delta t of the time window is calculated according to the initial moment and the ending moment of the sliding time window, when the delta t is smaller than the time threshold value required by the warm grinding, the starting time of the warm grinding recorded by the sliding time window is the effective warm grinding moment, the boundary condition of the warm grinding moment of the grinding groups when the running number of the current grinding groups is increased is generated at the starting moment of the sliding time window, and the constraint condition of the warm grinding moment prediction model of the grinding groups when the running number of the same grinding groups is increased is further used, and the relation of the lifting load of the unit and the warm grinding time of the grinding groups is excavated.
Further, the grinding set operation switching rule is as follows:
and (3) carrying out block coding according to the arrangement condition of 6 sets of grinding groups configured by the unit powder making system, wherein the lower, middle and upper layers of the front wall are respectively coded into a (1), a (2) and a (3), the lower, middle and upper layers of the rear wall are respectively coded into b (1), b (2) and b (3), the running number of the front wall grinding groups is n, the running number of the rear wall grinding groups is m, and the priority of the grinding group starting is subjected to conditional constraint to generate a grinding group running switching rule.
Still further, the pack initiation priority constraint is as follows:
(1)a(1)>a(2)>a(3)；
(2)b(1)>b(2)>b(3)；
(3)a(1)>b(1)；
(4)a(2)>b(2)；
(5)a(3)>b(3)；
(6)|n-m|<2。
further, in step 5.5, during the warm grinding of the grinding set, the cold and hot air regulating gates of the coal mill are divided into a cold air gate valve position determining mode, a cold air gate climbing boosting mode, a hot air gate valve position determining mode and a hot air gate climbing heating mode according to real-time running data of the grinding set, and a lifting rate PID controller, a hot air gate warm grinding PID controller and a cold air gate warm grinding PID controller are simultaneously introduced.
Furthermore, when the automatic warm grinding instruction of the grinding set is triggered, the whole control module of the cold and hot air door-adjusting warm grinding of the coal mill is called according to the following steps:
1) Entering a cold air door valve setting mode, and setting a cold air valve of the coal mill at a certain opening degree to perform cold air ventilation of the coal mill;
2) Entering a cold air door climbing boosting mode, generating a cold air door adjusting warm grinding instruction of the coal mill by a cold air door warm grinding PID controller, and automatically adjusting the outlet pressure of the coal mill;
3) The method comprises the steps of entering a hot air door valve setting mode, dividing a grinding set warm grinding state into cold state warm grinding and hot state warm grinding according to the temperature of primary air at an outlet of a unit air preheater, and then setting hot air valves of a coal mill at different opening degrees according to the grinding set warm grinding state to perform grinding set warm grinding and preheating;
4) And entering a hot air door climbing temperature rising mode, enabling the lifting speed PID controller and the hot air door warm grinding PID controller to simultaneously act in the mode, firstly calculating the outlet temperature rising rate of the coal mill, limiting the actual temperature rising rate by utilizing an upper limit module and a lower limit module of the temperature rising rate, then automatically generating an outlet temperature set value when the coal mill is warmed and ground by utilizing the lifting speed PID controller, finally enabling the hot air door warm grinding PID controller to generate a hot air door warm grinding command of the coal mill, and automatically adjusting the outlet temperature of the coal mill.
Still further, the cold air door warm mill PID controller is: according to the deviation between the outlet pressure of the coal mill and the set value of the warm mill wind pressure of the coal mill, automatically performing deviation-free adjustment, and generating a warm mill command of a cold wind regulating door of the coal mill;
the hot air door warm mill PID controller is as follows: according to the deviation between the outlet temperature of the coal mill and the outlet temperature set value of the coal mill, automatically performing deviation-free adjustment to generate a warm grinding instruction of a hot air valve of the coal mill;
the lifting rate PID controller is as follows: the proportional action coefficient of the parameters in the lifting rate PID controller is set to be 0, the integration time is set to be 60 seconds, the lifting rate PID controller is changed into a pure integration incremental PID, the input deviation is the outlet temperature rise rate of the coal mill limited by the upper limit and the lower limit modules of the temperature rise rate, when the actual temperature rise rate is within the limiting range, the outlet temperature set value of the coal mill output by the lifting rate PID controller is the outlet actual temperature of the coal mill, the hot air door-regulating grinding instruction of the coal mill is kept unchanged, when the actual temperature rise rate exceeds the upper limit of the temperature rise rate, the outlet temperature set value of the coal mill output by the lifting rate PID controller is smaller than the outlet actual temperature of the coal mill, the hot air door-regulating grinding instruction of the coal mill is smaller, the outlet temperature rise rate of the coal mill is reduced, when the actual temperature rise rate is smaller than the lower limit of the temperature rise rate, the outlet temperature set value of the coal mill output by the lifting rate PID controller is larger than the outlet actual temperature of the coal mill, and the outlet temperature rise rate of the coal mill is further improved.
Compared with the prior art, the invention has the following beneficial effects: according to the invention, the average coal quantity of the grinding group is calculated according to the real-time operation parameters of the current pulverizing system of the unit, the load capacity of the residual quantity of the current grinding group is calculated by combining the dynamic coal quantity pre-estimated value and the upper limit of the coal quantity of the grinding group, the sliding time window generated based on the statistical grinding group warm grinding starting time sequence is taken as a boundary condition, the grinding group warm grinding time is predicted, and meanwhile, the optimal sequencing of the grinding group warm grinding starting sequence is carried out by combining the conditions of grinding group arrangement, grinding group operation switching rules, grinding group maintenance or fault and the like, the grinding group warm grinding starting instruction is automatically sent, the warm grinding starting sequential control function group is called, and the grinding group warm grinding is automatically completed.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following brief description is given of the drawings required for the embodiments, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is an automatic control flow chart of a one-key automatic warm grinding control method of a coal-fired unit;
FIG. 2 is a schematic diagram of the control logic of the whole-course control module for the cold and hot air door-regulating warm mill of the coal mill.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the present specification more apparent, the technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments of the present specification and corresponding drawings. It will be apparent that the described embodiments are only some, but not all, embodiments of the invention. All other embodiments, which can be made by those skilled in the art without the exercise of inventive faculty, are intended to be within the scope of the invention, based on the embodiments in the specification.
Referring to fig. 1, a control flow chart of a one-key automatic warm grinding control method for a coal-fired unit according to an embodiment of the invention is shown.
A one-key automatic warm grinding control method of a coal-fired unit comprises the following steps:
step 1, judging whether a grinding group one-key automatic warm grinding function is put into operation, if yes, carrying out step 2, and if not, waiting in step 1;
step 2, calling a grinding set warm mill starting time model;
step 3, calling a grinding group warm mill starting sequence model according to the grinding group warm mill starting time model;
step 4, outputting a grinding group warm mill starting instruction according to the grinding group warm mill starting time model and the grinding group warm mill starting sequence model;
and 5, calling a warm mill start sequence control function group according to a mill group warm mill start instruction.
Specifically, the specific content of step 2 is as follows:
firstly, calculating to obtain the average coal quantity of an operation grinding group according to the current total coal quantity, the number of the operation grinding groups and the coal feeding bias of the unit, and simultaneously calculating to obtain the variable load feedforward of the boiler of the unit if the unit is subjected to 10 MW-20 MW load increase through the AGC rate of the unit, and estimating the dynamic coal quantity; then, combining the upper limit of the coal quantity of the grinding group to obtain the residual load capacity of the unit under the current grinding group; and finally, predicting the start time of the warm mill group by taking a sliding time window generated by the warm mill start time sequence of the warm mill group based on statistics as a boundary condition.
Specifically, the specific content of step 3 is as follows: and generating a grinding set operation switching rule through the arrangement of the unit grinding sets, comprehensively considering the running states of the grinding sets, and optimally sequencing the warm grinding start sequence of the grinding sets.
Specifically, step 5, the detailed steps of the coal-fired unit warm grinding starting sequential control function group for the configuration of the medium-speed direct-fired pulverizing system are as follows:
5.1, opening an electric flashboard door at the outlet of the coal feeder, closing an outlet pneumatic valve of a pebble coal box of the coal mill, and opening an inlet pneumatic valve of the pebble coal box of the coal mill;
5.2, opening an electric plugboard door at the inlet of the coal feeder and a sealing wind power baffle of the coal mill;
5.3, opening a pneumatic flashboard door of an outlet of the coal mill;
5.4, opening a cold and hot primary air pneumatic plugboard door of the coal mill;
5.5, calling a whole-process control module for cold and hot air door adjustment and warm grinding of the coal mill: the control of cold and hot air regulating doors of the coal mill is divided into a cold air door valve-fixing mode, a cold air door climbing boosting mode, a hot air door valve-fixing mode and a hot air door climbing heating mode, 4 modes are flexibly scheduled under the cold state and hot state working conditions of grinding groups, and the rate self-adaptive warm grinding control is automatically completed.
Specifically, the forming process of the statistical grinding group warm grinding starting time sequence is as follows:
and establishing a plurality of sliding time windows when the running number of the grinding groups is increased by utilizing a historical data set of the unit pulverizing system, wherein each sliding time window takes the moment when the pneumatic plugboard door at the outlet of the coal mill and the cold and hot primary air pneumatic plugboard door of the coal mill are in an open state as the initial representation of the sliding time window, the moment when the coal mill is started as the ending representation of the sliding time window, the time difference delta t of the time window is calculated according to the initial moment and the ending moment of the sliding time window, when the delta t is smaller than the time threshold value required by the warm grinding, the starting time of the warm grinding recorded by the sliding time window is the effective warm grinding moment, the boundary condition of the warm grinding moment of the grinding groups when the running number of the current grinding groups is increased is generated at the starting moment of the sliding time window, and the constraint condition of the warm grinding moment prediction model of the grinding groups when the running number of the same grinding groups is increased is further used, and the relation of the lifting load of the unit and the warm grinding time of the grinding groups is excavated.
Specifically, the grinding set operation switching rule is as follows: and (3) carrying out block coding according to the arrangement condition of 6 sets of grinding groups configured by the unit powder making system, wherein the lower, middle and upper layers of the front wall are respectively coded into a (1), a (2) and a (3), the lower, middle and upper layers of the rear wall are respectively coded into b (1), b (2) and b (3), the running number of the front wall grinding groups is n, the running number of the rear wall grinding groups is m, and the priority of the grinding group starting is subjected to conditional constraint to generate a grinding group running switching rule. The mill group start priority constraint is as follows:
(1)a(1)>a(2)>a(3)；
(2)b(1)>b(2)>b(3)；
(3)a(1)>b(1)；
(4)a(2)>b(2)；
(5)a(3)>b(3)；
(6)|n-m|<2。
in step 5.5, during the warm grinding of the grinding set, the cold and hot air regulating gates of the coal mill are divided into a cold air gate valve-setting mode, a cold air gate climbing boosting mode, a hot air gate valve-setting mode and a hot air gate climbing heating mode according to real-time running data of the grinding set, and a lifting speed PID controller, a hot air gate warm grinding PID controller and a cold air gate warm grinding PID controller are introduced.
When the automatic warm grinding instruction of the grinding set is triggered, the whole-course control module of the cold and hot air door adjusting and warm grinding of the coal mill is called according to the following steps:
1) Entering a cold air door valve setting mode, and setting a cold air valve of the coal mill at a certain opening degree to perform cold air ventilation of the coal mill;
2) Entering a cold air door climbing boosting mode, generating a cold air door adjusting warm grinding instruction of the coal mill by a cold air door warm grinding PID controller, and automatically adjusting the outlet pressure of the coal mill;
3) The method comprises the steps of entering a hot air door valve setting mode, dividing a grinding set warm grinding state into cold state warm grinding and hot state warm grinding according to the temperature of primary air at an outlet of a unit air preheater, and then setting hot air valves of a coal mill at different opening degrees according to the grinding set warm grinding state to perform grinding set warm grinding and preheating;
4) And entering a hot air door climbing temperature rising mode, enabling the lifting speed PID controller and the hot air door warm grinding PID controller to simultaneously act in the mode, firstly calculating the outlet temperature rising rate of the coal mill, limiting the actual temperature rising rate by utilizing an upper limit module and a lower limit module of the temperature rising rate, then automatically generating an outlet temperature set value when the coal mill is warmed and ground by utilizing the lifting speed PID controller, finally enabling the hot air door warm grinding PID controller to generate a hot air door warm grinding command of the coal mill, and automatically adjusting the outlet temperature of the coal mill.
The cold air door warm mill PID controller is: according to the deviation between the outlet pressure of the coal mill and the set value of the warm mill wind pressure of the coal mill, automatically performing deviation-free adjustment, and generating a warm mill command of a cold wind regulating door of the coal mill;
the hot air door warm mill PID controller is as follows: according to the deviation between the outlet temperature of the coal mill and the outlet temperature set value of the coal mill, automatically performing deviation-free adjustment to generate a warm grinding instruction of a hot air valve of the coal mill;
the lifting rate PID controller is as follows: the proportional action coefficient of the parameters in the lifting rate PID controller is set to be 0, the integration time is set to be 60 seconds, the lifting rate PID controller is changed into a pure integration incremental PID, the input deviation is the outlet temperature rise rate of the coal mill limited by the upper limit and the lower limit modules of the temperature rise rate, when the actual temperature rise rate is within the limiting range, the outlet temperature set value of the coal mill output by the lifting rate PID controller is the outlet actual temperature of the coal mill, the hot air door-regulating grinding instruction of the coal mill is kept unchanged, when the actual temperature rise rate exceeds the upper limit of the temperature rise rate, the outlet temperature set value of the coal mill output by the lifting rate PID controller is smaller than the outlet actual temperature of the coal mill, the hot air door-regulating grinding instruction of the coal mill is smaller, the outlet temperature rise rate of the coal mill is reduced, when the actual temperature rise rate is smaller than the lower limit of the temperature rise rate, the outlet temperature set value of the coal mill output by the lifting rate PID controller is larger than the outlet actual temperature of the coal mill, and the outlet temperature rise rate of the coal mill is further improved.
The invention designs a speed self-adaptive cold and hot air regulating door warm mill whole-course control module of a coal mill, which divides the control of the cold and hot air regulating doors of the coal mill into a cold air door valve position fixing mode, a cold air door climbing boosting mode, a hot air door valve position fixing mode and a hot air door climbing warming mode, flexibly schedules the 4 modes under the cold and hot working conditions of mill groups, and automatically completes the multi-working condition warm mill control of mill groups under wide load.
The foregoing is merely exemplary of the present invention and is not intended to limit the present invention. Various modifications and variations of the present invention will be apparent to those skilled in the art. Any modification, equivalent replacement, improvement, etc. which come within the spirit and principles of the invention are to be included in the scope of the claims of the present invention.
Claims (6)
1. The one-key automatic warm grinding control method for the coal-fired unit is characterized by comprising the following steps of:
step 1, judging whether a grinding group one-key automatic warm grinding function is put into operation, if yes, carrying out step 2, and if not, waiting in step 1;
step 2, calling a grinding set warm mill starting time model;
step 3, calling a grinding group warm mill starting sequence model according to the grinding group warm mill starting time model;
step 4, outputting a grinding group warm mill starting instruction according to the grinding group warm mill starting time model and the grinding group warm mill starting sequence model;
step 5, calling a warm mill start sequence control function group according to a mill group warm mill start instruction;
in step 5, the detailed steps of the coal-fired unit warm mill starting sequential control function group for configuring the medium-speed direct-fired pulverizing system are as follows:
5.1, opening an electric flashboard door at the outlet of the coal feeder, closing an outlet pneumatic valve of a pebble coal box of the coal mill, and opening an inlet pneumatic valve of the pebble coal box of the coal mill;
5.2, opening an electric plugboard door at the inlet of the coal feeder and a sealing wind power baffle of the coal mill;
5.3, opening a pneumatic flashboard door of an outlet of the coal mill;
5.4, opening a cold and hot primary air pneumatic plugboard door of the coal mill;
5.5, calling a whole-process control module for cold and hot air door adjustment and warm grinding of the coal mill: the control of cold and hot air regulating doors of the coal mill is divided into a cold air door valve-fixing mode, a cold air door climbing boosting mode, a hot air door valve-fixing mode and a hot air door climbing heating mode, 4 modes are flexibly scheduled under the cold state and hot state working conditions of grinding groups, and the rate self-adaptive warm grinding control is automatically completed;
in step 5.5, during the warm grinding of the grinding set, dividing the cold and hot air regulating doors of the coal mill into a cold air door valve-setting mode, a cold air door climbing boosting mode, a hot air door valve-setting mode and a hot air door climbing warming mode according to real-time running data of the grinding set, and simultaneously introducing a lifting rate PID controller, a hot air door warm grinding PID controller and a cold air door warm grinding PID controller;
when the automatic warm grinding instruction of the grinding set is triggered, the whole-course control module of the cold and hot air door adjusting and warm grinding of the coal mill is called according to the following steps:
1) Entering a cold air door valve setting mode, and setting a cold air valve of the coal mill at a certain opening degree to perform cold air ventilation of the coal mill;
2) Entering a cold air door climbing boosting mode, generating a cold air door adjusting warm grinding instruction of the coal mill by a cold air door warm grinding PID controller, and automatically adjusting the outlet pressure of the coal mill;
3) The method comprises the steps of entering a hot air door valve setting mode, dividing a grinding set warm grinding state into cold state warm grinding and hot state warm grinding according to the temperature of primary air at an outlet of a unit air preheater, and then setting hot air valves of a coal mill at different opening degrees according to the grinding set warm grinding state to perform grinding set warm grinding and preheating;
4) Entering a hot air door climbing temperature rising mode, enabling a lifting speed PID controller and a hot air door warm grinding PID controller to act simultaneously, firstly calculating the outlet temperature rising rate of the coal mill, limiting the actual temperature rising rate by utilizing an upper limit module and a lower limit module of the temperature rising rate, then automatically generating an outlet temperature set value when the coal mill is warmed and ground by utilizing the lifting speed PID controller, finally generating a hot air door warm grinding instruction of the coal mill by utilizing the hot air door warm grinding PID controller, and automatically adjusting the outlet temperature of the coal mill;
the cold air door warm mill PID controller is: according to the deviation between the outlet pressure of the coal mill and the set value of the warm mill wind pressure of the coal mill, automatically performing deviation-free adjustment, and generating a warm mill command of a cold wind regulating door of the coal mill;
the hot air door warm mill PID controller is as follows: according to the deviation between the outlet temperature of the coal mill and the outlet temperature set value of the coal mill, automatically performing deviation-free adjustment to generate a warm grinding instruction of a hot air valve of the coal mill;
the lifting rate PID controller is as follows: the proportional action coefficient of the parameters in the lifting rate PID controller is set to be 0, the integration time is set to be 60 seconds, the lifting rate PID controller is changed into a pure integration incremental PID, the input deviation is the outlet temperature rise rate of the coal mill limited by the upper limit and the lower limit modules of the temperature rise rate, when the actual temperature rise rate is within the limiting range, the outlet temperature set value of the coal mill output by the lifting rate PID controller is the outlet actual temperature of the coal mill, the hot air door-regulating grinding instruction of the coal mill is kept unchanged, when the actual temperature rise rate exceeds the upper limit of the temperature rise rate, the outlet temperature set value of the coal mill output by the lifting rate PID controller is smaller than the outlet actual temperature of the coal mill, the hot air door-regulating grinding instruction of the coal mill is smaller, the outlet temperature rise rate of the coal mill is reduced, when the actual temperature rise rate is smaller than the lower limit of the temperature rise rate, the outlet temperature set value of the coal mill output by the lifting rate PID controller is larger than the outlet actual temperature of the coal mill, and the outlet temperature rise rate of the coal mill is further improved.
2. The one-key automatic warm grinding control method of the coal-fired unit according to claim 1, wherein the specific contents of the step 2 are as follows:
firstly, calculating to obtain the average coal quantity of an operation grinding group according to the current total coal quantity, the number of the operation grinding groups and the coal feeding bias of the unit, and simultaneously calculating to obtain the variable load feedforward of the boiler of the unit if the unit is subjected to 10 MW-20 MW load increase through the AGC rate of the unit, and estimating the dynamic coal quantity; then, combining the upper limit of the coal quantity of the grinding group to obtain the residual load capacity of the unit under the current grinding group; and finally, predicting the start time of the warm mill group by taking a sliding time window generated by the warm mill start time sequence of the warm mill group based on statistics as a boundary condition.
3. The one-key automatic warm grinding control method of the coal-fired unit according to claim 1 or 2, wherein the specific contents of the step 3 are as follows: and generating a grinding set operation switching rule through the arrangement of the unit grinding sets, comprehensively considering the running states of the grinding sets, and optimally sequencing the warm grinding start sequence of the grinding sets.
4. The one-key automatic warm mill control method of the coal-fired unit according to claim 2, wherein the forming process of the statistical-based warm mill start time sequence of the mill group is as follows:
and establishing a plurality of sliding time windows when the running number of the grinding groups is increased by utilizing a historical data set of the unit pulverizing system, wherein each sliding time window takes the moment when the pneumatic plugboard door at the outlet of the coal mill and the cold and hot primary air pneumatic plugboard door of the coal mill are in an open state as the initial representation of the sliding time window, the moment when the coal mill is started as the ending representation of the sliding time window, the time difference delta t of the time window is calculated according to the initial moment and the ending moment of the sliding time window, when the delta t is smaller than the time threshold value required by the warm grinding, the starting time of the warm grinding recorded by the sliding time window is the effective warm grinding moment, the boundary condition of the warm grinding moment of the grinding groups when the running number of the current grinding groups is increased is generated at the starting moment of the sliding time window, and the constraint condition of the warm grinding moment prediction model of the grinding groups when the running number of the same grinding groups is increased is further used, and the relation of the lifting load of the unit and the warm grinding time of the grinding groups is excavated.
5. The method for controlling one-key automatic warm grinding of a coal-fired unit according to claim 3, wherein the grinding unit operation switching rule is as follows:
and (3) carrying out block coding according to the arrangement condition of 6 sets of grinding groups configured by the unit powder making system, wherein the lower, middle and upper layers of the front wall are respectively coded into a (1), a (2) and a (3), the lower, middle and upper layers of the rear wall are respectively coded into b (1), b (2) and b (3), the running number of the front wall grinding groups is n, the running number of the rear wall grinding groups is m, and the priority of the grinding group starting is subjected to conditional constraint to generate a grinding group running switching rule.
6. The one-key automatic warm mill control method of the coal-fired unit according to claim 5, wherein the mill start priority constraint conditions are as follows:
(1)a(1)>a(2)>a(3)；
(2)b(1)>b(2)>b(3)；
(3)a(1)>b(1)；
(4)a(2)>b(2)；
(5)a(3)>b(3)；
(6)|n-m|<2。
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| JPH01312315A (en) * | 1988-06-10 | 1989-12-18 | Babcock Hitachi Kk | Mill warming control device for coal burning boiler |
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| CN113713957B (en) * | 2021-08-12 | 2022-11-29 | 杭州意能电力技术有限公司 | Self-starting control method for pulverizing system of medium-speed roller type coal mill configured for thermal power generating unit |
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