CN113477389B - Control method and device of pulverizing system - Google Patents
Control method and device of pulverizing system Download PDFInfo
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- CN113477389B CN113477389B CN202110653167.8A CN202110653167A CN113477389B CN 113477389 B CN113477389 B CN 113477389B CN 202110653167 A CN202110653167 A CN 202110653167A CN 113477389 B CN113477389 B CN 113477389B
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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
- B02C23/04—Safety 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
- 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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Abstract
The invention discloses a control method and a device of a pulverizing system, wherein the method comprises the following steps: determining a current operation mode of the coal mill according to the opening quantity of the outlet door; determining an allowable switching mode of the coal mill according to the current running mode, the allowable change value of the opening quantity and the allowable minimum value; if a switching instruction for a target switching mode is detected, wherein the target switching mode belongs to the allowed switching mode, and the coal mill meets a target allowed condition corresponding to the target switching mode, switching the coal mill from the current operation mode to a target operation mode corresponding to the target switching mode; by changing the opening quantity of outlet doors of the coal mill and changing the operation mode of the coal mill, the coal powder concentration of the residual coal powder pipe can be improved based on closing the outlet doors of the coal mill with different quantities, so that the flexibility of coal quantity control of the coal powder making system in the deep peak shaving period is improved on the basis of ensuring the safety of a unit.
Description
Technical Field
The application relates to the technical field of thermal power plants, in particular to a control method and device of a pulverizing system.
Background
With the clean reformation of energy structures, the installed capacity of new energy power stations such as wind power stations and photovoltaic stations is rapidly increased, however, the new energy has the characteristics of randomness, intermittence, instability and the like, and the continuous rapid development of the installed capacity of the new energy power stations has adverse effects on the peak shaving of a power grid, so that the phenomena of wind discarding and light discarding are serious. Aiming at the difficult problem of new energy consumption, the national energy agency proposes to fully mine the peak regulation capacity of the existing system, and enhance the flexibility and adaptability of the system. And (3) the electric power peak regulation auxiliary service market operation rules of the power grid in each region are disputed, relevant peak regulation and paste repairing policies are formulated, and the coal-fired thermal power generating unit is guided to improve the operation flexibility through rewarding and punishing means.
At present, the main factors limiting the depth peak shaving downward detection of the coal-fired unit are poor stable combustion and poor fire detection when the boiler is under low load. If a certain power plant unit is operated by double grinding, the phenomenon of flicker and disappearance of fire detection often occurs when the total coal quantity is lower than 60t/h (the single grinding coal quantity is lower than 30 t/h), the flame of the burner is observed to be 'black dragon' on site, the total fuel quantity is low during the deep peak regulation, and the low coal dust concentration of each burner is one of the reasons for the phenomenon.
Therefore, how to improve the flexibility of coal quantity control of the pulverizing system in the deep peak shaving period on the basis of ensuring the safety of the unit is a technical problem to be solved at present.
Disclosure of Invention
The invention provides a control method of a pulverizing system, which is used for solving the technical problem of poor boiler combustion stability caused by too low coal quantity in the deep peak shaving period in the prior art, the method is applied to the pulverizing system comprising a coal feeder and a coal mill, the coal mill comprises a plurality of powder outlet pipes for conveying pulverized coal to a boiler combustor, and each powder outlet pipe is provided with an outlet door for controlling the on-off of the powder outlet pipe, and the method comprises the following steps:
determining a current operation mode of the coal mill according to the opening quantity of the outlet door;
determining an allowable switching mode of the coal mill according to the current running mode, the allowable change value of the opening quantity and the allowable minimum value;
if a switching instruction for a target switching mode is detected, wherein the target switching mode belongs to the allowed switching mode, and the coal mill meets a target allowed condition corresponding to the target switching mode, switching the coal mill from the current operation mode to a target operation mode corresponding to the target switching mode;
wherein the number of openings is different in the current operation mode and in the target operation mode.
Preferably, the allowable change value is one, and the allowable minimum value is half of the number of the powder tubes.
Preferably, the number of the powder outlet pipes is six, and the current operation mode of the coal mill is determined according to the opening number of the outlet doors, which specifically includes:
if the opening number is six, the current operation mode is a six-powder-tube operation mode;
if the opening number is five, the current operation mode is five powder pipe operation modes;
if the opening number is four, the current operation mode is four powder pipe operation modes;
and if the opening number is three, the current operation mode is three powder pipe operation modes.
Preferably, the allowable switching mode of the coal mill is determined according to the current operation mode, the allowable change value of the opening number and the allowable minimum value, and specifically includes:
if the current operation mode is the six-powder-tube operation mode, the allowable switching mode is that the six-powder-tube operation mode is switched to the five-powder-tube operation mode;
if the current operation mode is the five-powder-tube operation mode, the allowable switching mode is that the five-powder-tube operation mode is switched to the six-powder-tube operation mode or the five-powder-tube operation mode is switched to the four-powder-tube operation mode;
if the current operation mode is the four powder tube operation mode, the allowable switching mode is that the four powder tube operation mode is switched to the five powder tube operation mode or the four powder tube operation mode is switched to the three powder tube operation mode;
and if the current operation mode is the three powder tube operation mode, the permission switching mode is to switch from the three powder tube operation mode to the four powder tube operation mode.
Preferably, the method comprises the steps of,
if the target switching mode is that the six powder tube operation modes are switched to the five powder tube operation modes, the target permission condition is a first permission condition, and the first permission condition comprises: the coal quantity of the coal mill is not less than the first coal quantity and not more than the second coal quantity, the air quantity of the coal mill is not less than the first air quantity and not more than the second air quantity, and the opening quantity is five;
if the target switching mode is that the five powder tube operation modes are switched to the four powder tube operation modes, the target permission condition is a second permission condition, and the second permission condition comprises: the coal amount is not less than a third coal amount and not more than a fourth coal amount, the air amount is not less than a third air amount and not more than a fourth air amount, the opening quantity is four, the third coal amount is less than the first coal amount, the fourth coal amount is less than the second coal amount, the third air amount is less than the first air amount, and the fourth air amount is less than the second air amount;
if the target switching mode is that the four powder tube operation modes are switched to the three powder tube operation modes, the target permission condition is a third permission condition, and the third permission condition comprises: the coal amount is not less than a fifth coal amount and not more than a sixth coal amount, the air amount is not less than a fifth air amount and not more than a sixth air amount, the opening number is three, the fifth coal amount is less than the third coal amount, the sixth coal amount is less than the fourth coal amount, the fifth air amount is less than the third air amount, and the sixth air amount is less than the fourth air amount;
if the target switching mode is that the three powder tube operation modes are switched to the four powder tube operation modes, the target permission condition is the second permission condition;
if the target switching mode is that the four powder tube operation modes are switched to the five powder tube operation modes, the target allowing condition is the first allowing condition;
if the target switching mode is that the five powder tube operation modes are switched to the six powder tube operation modes, the target permission condition is a fourth permission condition, and the fourth permission condition comprises: the coal quantity is larger than a seventh coal quantity, the air quantity is larger than a seventh air quantity, the opening quantity is six, the seventh coal quantity is larger than the first coal quantity and smaller than the second coal quantity, and the seventh air quantity is larger than the first air quantity and smaller than the second air quantity.
Preferably, the method comprises the steps of,
the control logic of the five powder tube operation modes comprises: the coal quantity is not smaller than the first coal quantity and not larger than the second coal quantity, the air-coal curve meets a first curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of an outlet door of the coal feeder is canceled, the fire detection protection is six to five, the alarming condition of low primary air quantity of the coal feeder is that the air quantity is lower than a first threshold value, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than a second threshold value and is delayed for a preset time period, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the first threshold value and is delayed for the preset time period, and the first threshold value is larger than the second threshold value;
the control logic of the four powder tube operation modes comprises: the coal quantity is not smaller than the third coal quantity and not larger than the fourth coal quantity, the air-coal curve meets a second curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of a coal mill outlet door is canceled, the fire detection protection is six to five, the alarming condition of low primary air quantity of the coal mill is that the air quantity is lower than a third threshold value, the condition of low primary air quantity protection tripping of the coal mill is that the air quantity is lower than a fourth threshold value and the time delay is the preset time period, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the third threshold value and the time delay is the preset time period, the third threshold value is larger than the fourth threshold value and smaller than the first threshold value, and the fourth threshold value is smaller than the second threshold value;
the control logic of the three powder tube operation modes comprises: the coal quantity is not smaller than the fifth coal quantity and not larger than the sixth coal quantity, the air-coal curve meets a third curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of an outlet door of the coal feeder is canceled, the fire detection protection is that the number of fire is six, the alarm condition of low primary air quantity of the coal feeder is that the air quantity is lower than a fifth threshold, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than a sixth threshold and the time is delayed for the preset duration, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the fifth threshold and the time is delayed for the preset duration, the fifth threshold is larger than the sixth threshold and smaller than the third threshold, and the sixth threshold is smaller than the fourth threshold.
Preferably, the first curve is determined according to a first formula, and the first formula specifically includes: f=0.7029m+57.44, the second curve being determined according to a second formula, the second formula being specifically: f=0.8278 m+44.2, the third curve being determined according to a third formula, the third formula being specifically: f=0.8286m+34.3, where F is the air volume and M is the coal volume.
Correspondingly, the invention also provides a control device of the powder making system, which is applied to the powder making system comprising a coal feeder and a coal mill, wherein the coal mill comprises a plurality of powder outlet pipes for conveying pulverized coal to a boiler burner, and each powder outlet pipe is provided with an outlet door for controlling the on-off of the powder outlet pipe, and the device comprises:
the first determining module is used for determining the current operation mode of the coal mill according to the opening quantity of the outlet door;
the second determining module is used for determining the allowable switching mode of the coal mill according to the current running mode, the allowable change value of the starting quantity and the allowable minimum value;
the switching module is used for switching the coal mill from the current operation mode to a target operation mode corresponding to the target switching mode if a switching instruction for the target switching mode is detected, the target switching mode belongs to the allowed switching mode, and the coal mill meets target allowed conditions corresponding to the target switching mode;
wherein the number of openings is different in the current operation mode and in the target operation mode.
Preferably, the allowable change value is one, and the allowable minimum value is half of the number of the powder tubes.
Correspondingly, the invention also provides a computer readable storage medium, wherein the computer readable storage medium stores instructions, and when the instructions run on the terminal equipment, the terminal equipment is caused to execute the control method of the powder making system.
Compared with the prior art, the invention has the following beneficial effects:
by applying the technical scheme, in a pulverizing system comprising a coal feeder and a coal pulverizer, the coal pulverizer comprises a plurality of powder outlet pipes for conveying pulverized coal to a boiler burner, each powder outlet pipe is provided with an outlet door for controlling the on-off of the powder outlet pipe, and the current operation mode of the coal pulverizer is determined according to the opening quantity of the outlet doors; determining an allowable switching mode of the coal mill according to the current running mode, the allowable change value of the opening quantity and the allowable minimum value; if a switching instruction for a target switching mode is detected, wherein the target switching mode belongs to the allowed switching mode, and the coal mill meets a target allowed condition corresponding to the target switching mode, switching the coal mill from the current operation mode to a target operation mode corresponding to the target switching mode; the starting quantity is different between the current operation mode and the target operation mode, the operation mode of the coal mill is changed by changing the starting quantity of outlet doors of the coal mill, the coal powder concentration of the residual coal powder pipes can be improved based on closing the outlet doors of the coal mill with different quantities, and the boiler fuel quantity is further reduced during the deep peak shaving of the unit, so that the deep peak shaving amplitude of the unit is not limited by the minimum coal quantity of the boiler, the flexibility of coal quantity control of the coal pulverizing system during the deep peak shaving is improved on the basis of ensuring the safety of the unit, and the deep peak shaving capacity of the unit is enhanced.
Drawings
In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the following description are only some embodiments of the present application, and that other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
Fig. 1 is a schematic flow chart of a control method of a pulverizing system according to an embodiment of the present invention;
fig. 2 is a schematic structural diagram of a control device of a pulverizing system according to an embodiment of the present invention.
Detailed Description
The following description of the embodiments of the present application will be made clearly and fully with reference to the accompanying drawings, in which it is evident that the embodiments described are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
The embodiment of the invention provides a control method of a powder making system, which is applied to the powder making system comprising a coal feeder and a coal mill, wherein the coal mill comprises a plurality of powder outlet pipes for conveying pulverized coal to a boiler burner, and each powder outlet pipe is provided with an outlet door for controlling the on-off of the powder outlet pipe, as shown in figure 1, and the method comprises the following steps:
step S101, determining the current operation mode of the coal mill according to the opening quantity of the outlet door.
In this embodiment, the pulverizing system may be a positive pressure direct-fired pulverizing system, including feeder and coal mill, the coal mill includes many powder outlet pipes that are used for carrying pulverized coal to boiler burner, each be provided with the outlet door of control powder outlet pipe break-make on the powder outlet pipe, each powder outlet pipe corresponds respectively and connects one and set up the combustor at the boiler, and this combustor can be for opposite-flow whirl combustor or wall type cutting garden combustor, and every combustor has the ability of stable burning of independent organization. The coal feeder feeds coal to the coal mill, the coal mill grinds the coal, and then the coal powder is conveyed to each coal powder pipeline through the primary air after passing through the coal powder separator, and enters each combustor through each outlet door for combustion.
The coal mill is put in different operation modes by changing the opening number of the outlet doors, so that the current operation mode can be determined according to the opening number.
And step S102, determining the allowable switching mode of the coal mill according to the current operation mode, the allowable change value of the starting quantity and the allowable minimum value.
In this embodiment, different operation modes correspond to different opening numbers, and each outlet door needs to be controlled according to an allowable change value and an allowable minimum value of the opening number, so that an allowable switching manner for switching from the current operation mode to other operation modes can be determined according to the current operation mode and the allowable change value and the allowable minimum value of the opening number.
In order to improve the safety of the unit, in the preferred embodiment of the application, the allowable change value is one, and the allowable minimum value is half of the number of the powder tubes.
In this embodiment, the allowable change value is one, that is, the opening number can be increased by one or reduced by one according to different conditions, and meanwhile, the opening number is not less than half of the number of the powder tubes, because if the opening number is too low, the normal operation of the coal mill is affected, and the combustion stability of the boiler is further affected.
In order to accurately determine the current operation mode, in a preferred embodiment of the present application, the number of the powder outlet pipes is six, and the current operation mode of the coal mill is determined according to the opening number of the outlet door, specifically:
if the opening number is six, the current operation mode is a six-powder-tube operation mode;
if the opening number is five, the current operation mode is five powder pipe operation modes;
if the opening number is four, the current operation mode is four powder pipe operation modes;
and if the opening number is three, the current operation mode is three powder pipe operation modes.
The person skilled in the art can also select coal mills provided with other numbers of outlet pipes and determine different current operation modes according to different opening numbers, which does not affect the protection scope of the application.
In order to reliably determine the allowable switching mode, in a preferred embodiment of the present application, the allowable switching mode of the coal mill is determined according to the current operation mode, the allowable change value of the opening number and the allowable minimum value, and specifically includes:
if the current operation mode is the six-powder-tube operation mode, the allowable switching mode is that the six-powder-tube operation mode is switched to the five-powder-tube operation mode;
if the current operation mode is the five-powder-tube operation mode, the allowable switching mode is that the five-powder-tube operation mode is switched to the six-powder-tube operation mode or the five-powder-tube operation mode is switched to the four-powder-tube operation mode;
if the current operation mode is the four powder tube operation mode, the allowable switching mode is that the four powder tube operation mode is switched to the five powder tube operation mode or the four powder tube operation mode is switched to the three powder tube operation mode;
and if the current operation mode is the three powder tube operation mode, the permission switching mode is to switch from the three powder tube operation mode to the four powder tube operation mode.
In this embodiment, if the current operation mode is the six-powder-tube operation mode, since all the six outlet doors are opened, only the number of openings can be reduced, the allowable change value of the number of openings is one, the number of openings is five after the change, and the minimum allowable value of the number of openings is three, so that the switching mode is allowed to be switched from the six-powder-tube operation mode to the five-powder-tube operation mode.
If the current operation mode is five powder tube operation modes, the opening quantity can be increased or reduced, the allowable change value of the opening quantity is one, the opening quantity is six or four after the change, the allowable minimum value of three of the opening quantity is met, and the allowable switching mode is that the five powder tube operation modes are switched to the six powder tube operation modes or the five powder tube operation modes are switched to the four powder tube operation modes.
Other determination manners of the allowable switching manner are similar to the above determination process, and are not described herein.
Step S103, if a switching instruction for a target switching mode is detected and the target switching mode belongs to the allowable switching mode, and the coal mill meets a target allowable condition corresponding to the target switching mode, switching the coal mill from the current operation mode to a target operation mode corresponding to the target switching mode.
In this embodiment, one or more mode switching buttons corresponding to different target switching modes may be set on the DCS operation interface, and an operator may input a switching instruction for the target switching mode by clicking the mode switching button, and if the target switching mode belongs to the allowable switching mode and the coal mill satisfies the target allowable condition corresponding to the target switching mode, switch the coal mill from the current operation mode to the target operation mode corresponding to the target switching mode. The switching of the operation mode is performed by changing the number of openings of the outlet door, which is different in the current operation mode and in the target operation mode.
The person skilled in the art can flexibly set different target allowable conditions according to actual unit parameters, and the protection scope of the application is not affected.
In order to reliably perform mode switching, in a preferred embodiment of the present application, if the target switching mode is to switch from the six-powder-tube operation mode to the five-powder-tube operation mode, the target permission condition is a first permission condition, and the first permission condition includes: the coal quantity of the coal mill is not less than the first coal quantity and not more than the second coal quantity, the air quantity of the coal mill is not less than the first air quantity and not more than the second air quantity, and the opening quantity is five;
if the target switching mode is that the five powder tube operation modes are switched to the four powder tube operation modes, the target permission condition is a second permission condition, and the second permission condition comprises: the coal amount is not less than a third coal amount and not more than a fourth coal amount, the air amount is not less than a third air amount and not more than a fourth air amount, the opening quantity is four, the third coal amount is less than the first coal amount, the fourth coal amount is less than the second coal amount, the third air amount is less than the first air amount, and the fourth air amount is less than the second air amount;
if the target switching mode is that the four powder tube operation modes are switched to the three powder tube operation modes, the target permission condition is a third permission condition, and the third permission condition comprises: the coal amount is not less than a fifth coal amount and not more than a sixth coal amount, the air amount is not less than a fifth air amount and not more than a sixth air amount, the opening number is three, the fifth coal amount is less than the third coal amount, the sixth coal amount is less than the fourth coal amount, the fifth air amount is less than the third air amount, and the sixth air amount is less than the fourth air amount;
if the target switching mode is that the three powder tube operation modes are switched to the four powder tube operation modes, the target permission condition is the second permission condition;
if the target switching mode is that the four powder tube operation modes are switched to the five powder tube operation modes, the target allowing condition is the first allowing condition;
if the target switching mode is that the five powder tube operation modes are switched to the six powder tube operation modes, the target permission condition is a fourth permission condition, and the fourth permission condition comprises: the coal quantity is larger than a seventh coal quantity, the air quantity is larger than a seventh air quantity, the opening quantity is six, the seventh coal quantity is larger than the first coal quantity and smaller than the second coal quantity, and the seventh air quantity is larger than the first air quantity and smaller than the second air quantity.
To further improve the reliability of mode switching, in a preferred embodiment of the present application, the first coal amount is 23.5 (t/h), the second coal amount is 35 (t/h), the third coal amount is 18 (t/h), the fourth coal amount is 30 (t/h), the fifth coal amount is 14 (t/h), the sixth coal amount is 21 (t/h), the seventh coal amount is 25 (t/h), the first air volume is 73.3 (t/h), the second air volume is 86.5 (t/h), the third air volume is 58.7 (t/h), the fourth air volume is 69.2 (t/h), the fifth air volume is 44 (t/h), the sixth air volume is 51.9 (t/h), and the seventh air volume is 80 (t/h).
In order to improve the safety of each operation mode, in a preferred embodiment of the present application, the control logic of the five-root canal operation mode includes: the coal quantity is not smaller than the first coal quantity and not larger than the second coal quantity, the air-coal curve meets a first curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of an outlet door of the coal feeder is canceled, the fire detection protection is six to five, the alarming condition of low primary air quantity of the coal feeder is that the air quantity is lower than a first threshold value, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than a second threshold value and is delayed for a preset time period, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the first threshold value and is delayed for the preset time period, and the first threshold value is larger than the second threshold value;
the control logic of the four powder tube operation modes comprises: the coal quantity is not smaller than the third coal quantity and not larger than the fourth coal quantity, the air-coal curve meets a second curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of a coal mill outlet door is canceled, the fire detection protection is six to five, the alarming condition of low primary air quantity of the coal mill is that the air quantity is lower than a third threshold value, the condition of low primary air quantity protection tripping of the coal mill is that the air quantity is lower than a fourth threshold value and the time delay is the preset time period, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the third threshold value and the time delay is the preset time period, the third threshold value is larger than the fourth threshold value and smaller than the first threshold value, and the fourth threshold value is smaller than the second threshold value;
the control logic of the three powder tube operation modes comprises: the coal quantity is not smaller than the fifth coal quantity and not larger than the sixth coal quantity, the air-coal curve meets a third curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of an outlet door of the coal feeder is canceled, the fire detection protection is that the number of fire is six, the alarm condition of low primary air quantity of the coal feeder is that the air quantity is lower than a fifth threshold, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than a sixth threshold and the time is delayed for the preset duration, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the fifth threshold and the time is delayed for the preset duration, the fifth threshold is larger than the sixth threshold and smaller than the third threshold, and the sixth threshold is smaller than the fourth threshold.
In this embodiment, the wind-coal curve is a curve representing a corresponding relation between the air volume and the coal volume of the coal mill, and the fire detection protection is six or five, i.e. five of six detection points detect fire detection protection actions when the fire detection is lost.
In order to further improve the safety of each operation mode, in a preferred embodiment of the present application, the first upper and lower limits are ±10, the first threshold is 55 (t/h), the second threshold is 50 (t/h), the third threshold is 45 (t/h), the fourth threshold is 40 (t/h), the fifth threshold is 35 (t/h), the sixth threshold is 30 (t/h), and the preset duration is 60s.
In order to further improve the safety of each operation mode, in a preferred embodiment of the present application, the first curve is determined according to a first formula, where the first formula specifically is: f=0.7029m+57.44, the second curve being determined according to a second formula, the second formula being specifically: f=0.8278 m+44.2, the third curve being determined according to a third formula, the third formula being specifically: f=0.8286m+34.3, where F is the air volume and M is the coal volume.
By changing the opening quantity of outlet doors of the coal mill and changing the operation mode of the coal mill, the coal powder concentration of the residual coal powder pipes can be improved based on closing the outlet doors of the coal mill with different quantities, and the boiler fuel quantity can be further reduced during the deep peak shaving of the unit, so that the deep peak shaving amplitude of the unit is not limited by the lowest coal quantity of the boiler, the flexibility of coal quantity control of the coal pulverizing system during the deep peak shaving is improved on the basis of ensuring the safety of the unit, and the deep peak shaving capacity of the unit is enhanced.
In order to further explain the technical idea of the invention, the technical scheme of the invention is described with specific application scenarios.
Each coal mill of a power plant unit has 6 independent outlet doors corresponding to 6 opposite-impact swirl burners, and each burner has the capability of independently organizing stable combustion. Under the condition that the conditions such as the primary air speed of a single coal powder pipe and the air-coal ratio of the coal mill are met, the coal powder concentration of the rest coal powder pipes is improved by reducing the primary air quantity of the coal mill and closing 1 to 3 coal mill outlet doors.
The specific control logic is as follows:
1. the normal mode (namely six powder pipes running mode) running of the coal mill is switched to the permissible condition of five powder pipes running mode:
(1) Coal amount: 23.5 (t/h) -35 (t/h);
(2) Air volume: 73.3 (t/h) -86.5 (t/h)
(3) Number of coal mill outlet door openings: 5.
2. Five powder pipe operation mode control logic:
(1) Coal amount interval: 23.5 (t/h) -35 (t/h);
(2) Wind-coal curve: air volume (t/h) = 0.7029 coal volume (t/h) +57.44;
(3) The upper and lower limits of the command deviation of the coal feeder are changed from +/-5 to +/-10;
(4) Canceling a coal mill outlet gate trip grinding logic;
(5) Fire detection protection: 6, taking 5;
(6) Low primary air quantity alarm of coal mill: 55 (t/h);
(7) Primary air quantity low protection tripping of coal mill: 50 (t/h), delay for 60s.
(8) Low primary air quantity protective trip of coal feeder: 55 (t/h), delay for 60s.
3. The permissible condition for switching the operation modes of the five powder pipes to the operation modes of the four powder pipes is as follows:
(1) Coal amount: 18 (t/h) -30 (t/h);
(2) Air volume: 58.7 (t/h) -69.2 (t/h)
(3) Number of coal mill outlet door openings: 4;
4. four powder tube operation mode control logic:
(1) Coal amount interval: 18 (t/h) -30 (t/h);
(2) Wind-coal curve: air volume (t/h) = 0.8278 coal volume (t/h) +44.2;
(3) The upper and lower limits of the command deviation of the coal feeder are changed from +/-5 to +/-10;
(4) Canceling a coal mill outlet gate trip grinding logic;
(5) Fire detection protection: 6, taking 5;
(6) Low primary air quantity alarm: 45 (t/h);
(7) Primary air quantity low protection tripping: 40 (t/h), delay for 60s.
(8) Low primary air quantity protective trip of coal feeder: 45 (t/h), delay for 60s.
5. The four powder tube operation modes are switched to the three powder tube operation modes under the allowable conditions:
(1) Coal amount: 14 (t/h) -21 (t/h);
(2) Air volume: 44 (t/h) -51.9 (t/h);
(3) Number of coal mill outlet door openings: 3.
6. Control logic of three powder tube operation modes:
(1) Coal amount interval: 14 (t/h) -21 (t/h);
(2) Wind-coal curve: air volume (t/h) = 0.8286 coal volume (t/h) +34.3;
(3) The upper and lower limits of the command deviation of the coal feeder are changed from +/-5 to +/-10;
(4) Canceling a coal mill outlet gate trip grinding logic;
(5) Fire detection protection: 6, taking 5;
(6) Low primary air quantity alarm: 35 (t/h);
(7) Primary air quantity low protection tripping: 30 (t/h), delay for 60s.
(8) Low primary air quantity protective trip of coal feeder: 35 (t/h), delay for 60s.
7. The permission condition for switching the three-powder-tube operation mode to the four-powder-tube operation mode is as follows:
(1) Coal amount: 18 (t/h) -30 (t/h);
(2) Air volume: 58.7 (t/h) -69.2 (t/h);
(3) Number of coal mill outlet door openings: 4.
8. The permission condition that four powder pipe operation modes are switched to five powder pipe operation modes is as follows:
(1) Coal amount: 23.5 (t/h) -35 (t/h);
(2) Air volume: 73.3 (t/h) -86.5 (t/h);
(3) Number of coal mill outlet door openings: 5.
9. The permissible condition for switching the operation mode of the five powder pipes to the operation mode of the six powder pipes is as follows:
(1) Coal amount: greater than 25 (t/h);
(2) Air volume: greater than 80 (t/h);
(3) Number of coal mill outlet door openings: 6.
During the deep peak regulation of the power plant #3 unit, the small coal quantity mode (comprising five-powder-tube operation mode, four-powder-tube operation mode and three-powder-tube operation mode) of the 3B coal mill is tested, the coal quantity of the 3B coal mill is successfully reduced to 20t/h, the total coal quantity of the unit is reduced to 45t/h, the load of the unit is reduced to 80MW, and the load of the unit is reduced by 10MW compared with that of the #4 unit.
The low coal quantity operation mode of the coal mill can successfully reduce the lower limit of the coal quantity of the coal mill, thereby reducing the total coal quantity of the unit and enhancing the deep peak regulation capacity of the unit. The load of the unit 10MW can be reduced by closing 2 coal powder pipes of 1 coal mill. If two coal mills of a single unit are operated in a small coal quantity mode, the 20MW load of the unit can be reduced, and the deep adjustment of the unit per hour can be more than 10000 yuan in non-heating seasons.
Corresponding to a control method of a coal pulverizing system in the embodiments of the present application, the embodiments of the present application further provide a control device of a coal pulverizing system, which is applied to a coal pulverizing system including a coal feeder and a coal pulverizer, where the coal pulverizer includes a plurality of powder outlet pipes for conveying pulverized coal to a boiler burner, and each of the powder outlet pipes is provided with an outlet door for controlling on-off of the powder outlet pipe, as shown in fig. 2, and the device includes:
a first determining module 201, configured to determine a current operation mode of the coal mill according to the number of opening outlet doors;
a second determining module 202, configured to determine an allowable switching manner of the coal mill according to the current operation mode, the allowable change value of the number of openings, and an allowable minimum value;
a switching module 203, configured to switch the coal mill from the current operation mode to a target operation mode corresponding to a target switching mode if a switching instruction for the target switching mode is detected and the target switching mode belongs to the allowed switching mode and the coal mill meets a target allowed condition corresponding to the target switching mode;
wherein the number of openings is different in the current operation mode and in the target operation mode.
In a specific application scenario of the present application, the allowable change value is one, and the allowable minimum value is half of the number of the powder tubes.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, one of ordinary skill in the art will appreciate that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not drive the essence of the corresponding technical solutions to depart from the spirit and scope of the technical solutions of the embodiments of the present application.
Claims (4)
1. The control method of the pulverizing system is applied to the pulverizing system comprising a coal feeder and a coal mill, wherein the coal mill comprises a plurality of powder outlet pipes for conveying pulverized coal to a boiler burner, and outlet doors for controlling the on-off of the powder outlet pipes are arranged on each powder outlet pipe, and the control method is characterized by comprising the following steps:
determining a current operation mode of the coal mill according to the opening quantity of the outlet door;
determining an allowable switching mode of the coal mill according to the current running mode, the allowable change value of the opening quantity and the allowable minimum value;
if a switching instruction for a target switching mode is detected, wherein the target switching mode belongs to the allowed switching mode, and the coal mill meets a target allowed condition corresponding to the target switching mode, switching the coal mill from the current operation mode to a target operation mode corresponding to the target switching mode;
wherein the number of turns on is different in the current operation mode and in the target operation mode;
the allowable change value is one, and the allowable minimum value is half of the number of the powder tubes;
the number of the powder outlet pipes is six, and the current running mode of the coal mill is determined according to the opening number of the outlet doors, specifically:
if the opening number is six, the current operation mode is a six-powder-tube operation mode;
if the opening number is five, the current operation mode is five powder pipe operation modes;
if the opening number is four, the current operation mode is four powder pipe operation modes;
if the opening number is three, the current operation mode is three powder pipe operation modes;
determining an allowable switching mode of the coal mill according to the current running mode, the allowable change value of the opening quantity and the allowable minimum value, wherein the allowable switching mode specifically comprises the following steps:
if the current operation mode is the six-powder-tube operation mode, the allowable switching mode is that the six-powder-tube operation mode is switched to the five-powder-tube operation mode;
if the current operation mode is the five-powder-tube operation mode, the allowable switching mode is that the five-powder-tube operation mode is switched to the six-powder-tube operation mode or the five-powder-tube operation mode is switched to the four-powder-tube operation mode;
if the current operation mode is the four powder tube operation mode, the allowable switching mode is that the four powder tube operation mode is switched to the five powder tube operation mode or the four powder tube operation mode is switched to the three powder tube operation mode;
if the current operation mode is the three powder tube operation mode, the allowable switching mode is to switch from the three powder tube operation mode to the four powder tube operation mode;
if the target switching mode is that the six powder tube operation modes are switched to the five powder tube operation modes, the target permission condition is a first permission condition, and the first permission condition comprises: the coal quantity of the coal mill is not less than the first coal quantity and not more than the second coal quantity, the air quantity of the coal mill is not less than the first air quantity and not more than the second air quantity, and the opening quantity is five;
if the target switching mode is that the five powder tube operation modes are switched to the four powder tube operation modes, the target permission condition is a second permission condition, and the second permission condition comprises: the coal amount is not less than a third coal amount and not more than a fourth coal amount, the air amount is not less than a third air amount and not more than a fourth air amount, the opening quantity is four, the third coal amount is less than the first coal amount, the fourth coal amount is less than the second coal amount, the third air amount is less than the first air amount, and the fourth air amount is less than the second air amount;
if the target switching mode is that the four powder tube operation modes are switched to the three powder tube operation modes, the target permission condition is a third permission condition, and the third permission condition comprises: the coal amount is not less than a fifth coal amount and not more than a sixth coal amount, the air amount is not less than a fifth air amount and not more than a sixth air amount, the opening number is three, the fifth coal amount is less than the third coal amount, the sixth coal amount is less than the fourth coal amount, the fifth air amount is less than the third air amount, and the sixth air amount is less than the fourth air amount;
if the target switching mode is that the three powder tube operation modes are switched to the four powder tube operation modes, the target permission condition is the second permission condition;
if the target switching mode is that the four powder tube operation modes are switched to the five powder tube operation modes, the target allowing condition is the first allowing condition;
if the target switching mode is that the five powder tube operation modes are switched to the six powder tube operation modes, the target permission condition is a fourth permission condition, and the fourth permission condition comprises: the coal quantity is larger than a seventh coal quantity, the air quantity is larger than a seventh air quantity, the opening quantity is six, the seventh coal quantity is larger than the first coal quantity and smaller than the second coal quantity, and the seventh air quantity is larger than the first air quantity and smaller than the second air quantity.
2. The method of claim 1, wherein,
the control logic of the five powder tube operation modes comprises: the coal quantity is not smaller than the first coal quantity and not larger than the second coal quantity, the air-coal curve meets a first curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of an outlet door of the coal feeder is canceled, the fire detection protection is six to five, the alarming condition of low primary air quantity of the coal feeder is that the air quantity is lower than a first threshold value, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than a second threshold value and is delayed for a preset time period, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the first threshold value and is delayed for the preset time period, and the first threshold value is larger than the second threshold value;
the control logic of the four powder tube operation modes comprises: the coal quantity is not smaller than the third coal quantity and not larger than the fourth coal quantity, the air-coal curve meets a second curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of a coal mill outlet door is canceled, the fire detection protection is six to five, the alarming condition of low primary air quantity of the coal mill is that the air quantity is lower than a third threshold value, the condition of low primary air quantity protection tripping of the coal mill is that the air quantity is lower than a fourth threshold value and the time delay is the preset time period, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the third threshold value and the time delay is the preset time period, the third threshold value is larger than the fourth threshold value and smaller than the first threshold value, and the fourth threshold value is smaller than the second threshold value;
the control logic of the three powder tube operation modes comprises: the coal quantity is not smaller than the fifth coal quantity and not larger than the sixth coal quantity, the air-coal curve meets a third curve, the upper limit and the lower limit of the command deviation of the coal feeder are the first upper limit and the lower limit, the trip-grinding logic of an outlet door of the coal feeder is canceled, the fire detection protection is that the number of fire is six, the alarm condition of low primary air quantity of the coal feeder is that the air quantity is lower than a fifth threshold, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than a sixth threshold and the time is delayed for the preset duration, the condition of low primary air quantity protection tripping of the coal feeder is that the air quantity is lower than the fifth threshold and the time is delayed for the preset duration, the fifth threshold is larger than the sixth threshold and smaller than the third threshold, and the sixth threshold is smaller than the fourth threshold.
3. The method of claim 2, wherein the first curve is determined according to a first formula, the first formula being specifically: f=0.7029m+57.44, the second curve being determined according to a second formula, the second formula being specifically: f=0.8278 m+44.2, the third curve being determined according to a third formula, the third formula being specifically: f=0.8286m+34.3, where F is the air volume and M is the coal volume.
4. A computer readable storage medium, characterized in that the computer readable storage medium has stored therein instructions, which when run on a terminal device, cause the terminal device to perform a method of controlling a milling system according to any one of claims 1-3.
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