Summary of the invention
The present invention will overcome the shortcoming that above-mentioned prior art exists, provide a kind of comprehensive combustion in circular fluidized bed boiler self-regulating method, this method is coordinated a plurality of subsystems of comprehensive combustion in circular fluidized bed boiler system to connect together, interact and limit mutually again, improved its stability greatly.
Technical scheme of the present invention is as follows:
The present invention has adopted the design of " with air quantity rapid adjustment load, come steady load with coal-supplying amount, adjust bed temperature with coal-supplying amount, guarantee economy with the coal-air ratio rapid adjustment with oxygen content, adjust negative pressure with air inducing ".
The concrete grammar step is as follows:
(1) combustion chamber draft is regulated and is adopted the single loop regulative mode, to the outer fixed value mode of giving of combustion chamber draft set-point, combustion chamber draft process measurement value is got one or three with two get one and filtering or one order inertia processing method, carry out combustion chamber draft proportional integral derivative controller (hereinafter to be referred as PID) control module parameter, air-supply feedforward initial setting during debugging earlier, look object process performance graph on this basis and change, above-mentioned parameter is adjusted accordingly;
(2) boiler load is regulated and is adopted compound tandem loop regulative mode, boiler load (main vapour pressure) set-point adopts the outer fixed value mode of giving, to boiler load (main vapour pressure), the recirculating fluidized bed bed temperature, the ash concentration measured value is got one or three with two and is got one and filtering or one order inertia processing method, carry out boiler load pid control module parameter during debugging earlier, bed temperature pid correction module parameter, ash concentration pid correction module parameter, boiler load is paid pid control module parameter initial setting, look object process performance graph on this basis and change, above-mentioned parameter is adjusted accordingly;
(3) the recirculating fluidized bed bed temperature is regulated and is adopted compound tandem loop regulative mode, to recirculating fluidized bed bed temperature set-point servo-actuated set-point mode, adopt two to get one or three and get one and filtering or one order inertia processing method to recirculating fluidized bed bed temperature, main vapour pressure, oxygen content of smoke gas measured value, carry out bed temperature pid control module parameter, main vapour pressure pid correction module parameter, oxygen content pid correction module parameter during debugging earlier, pay pid control module parameter initial setting, look object process performance graph on this basis and change, above-mentioned parameter is adjusted accordingly;
(4) flue gas oxygen content of CFBB is regulated and is adopted tandem loop regulative mode, to flue gas oxygen content set-point servo-actuated set-point mode, adopt two to get one or three and get one and filtering or one order inertia processing method to flue gas oxygen content process measurement value, carry out oxygen content master pid control module parameter, oxygen content during debugging earlier and pay pid control module parameter, coal-supplying amount feedforward initial setting, look object process performance graph on this basis and change, above-mentioned parameter is adjusted accordingly;
Combustion chamber draft regulating loop, boiler load regulating loop, recirculating fluidized bed bed temperature regulating loop, flue gas oxygen content regulating loop are carried out classifying alarm respectively to realize monitor loop.
Major advantage of the present invention is: owing to the multivariable at CFBB, close coupling, the characteristics that inertia is big, adopted and used intermediate variable to participate in the technical scheme of the middle correction link of regulating system, and according to the difference of the inertia constant of its different variablees, the appropriate proportional integral derivative controller of adjusting (PID) is regulated parameter and is reasonably selected intermediate variable, comprehensive combustion in circular fluidized bed boiler system subsystem is coordinated together, restriction mutually again interacts, thereby improved stability greatly, and can eliminate disturbance fast, its economic benefit also obviously improves.
The specific embodiment:
Referring to Fig. 1, in the step (1) of technology case:
Described combustion chamber draft is regulated the mode that adopts single loop to regulate, combustion chamber draft set-point signal, combustion chamber draft process measurement value signal input combustion chamber draft pid control module, pid control module is exported to soft manual operation device module, soft manual operation device module is exported to outside executing agency---air-introduced machine outlet damper or frequency converter, and air output is as feedforward;
Described combustion chamber draft pid control module parameter is set at: proportional band P=120%~180%, and the time of integration, Ti=40~80s exported rate of change=0.3%~1%; Air output feedforward is set at: differential coefficient Kd2=1~2, derivative time Td2=10~20s.
During described combustion chamber draft single loop is regulated, when actuator is two, adopt the balance module of two actuators; Described air output is to be converted and obtained by the air-supply throttle opening of measuring, air-supply pressure reduction, perhaps directly adopts the air flow rate of measuring.
As stated above, the result of combustion chamber draft adjusting debugging is: combustion chamber draft dynamic process characteristic changes in the positive and negative 25 handkerchief scopes of set-point; For the variation of (MCR) 5% at full capacity, overshoot 30 handkerchiefs, dynamic time are 2 process cycles.
Referring to Fig. 2, in technical scheme steps (2):
Described boiler load is regulated and is adopted compound tandem loop regulative mode to be, boiler load (main vapour pressure) set-point signal, boiler load (main vapour pressure) measured value signal input main vapour pressure pid control module, if recirculating fluidized bed bed temperature point position adopts bed temperature pid correction module when higher, recirculating fluidized bed bed temperature set-point signal, bed temperature measured value signal input bed temperature pid correction module, while recirculating fluidized bed ash concentration set-point signal, ash concentration calculated value signal input ash concentration pid correction module, when being no more than 4000J/kg, the variation of coal caloric value adopts ash concentration pid correction module, when the coal caloric value changes above 4000J/kg,, ash concentration pid correction module realizes by being multiply by the heat correction coefficient; The output of main vapour pressure pid control module, the output of bed temperature pid correction module, ash concentration correction module output weighting summation are paid pid control module set-point signal as boiler load, primary air flow or blast are paid pid control module as boiler load measured value signal, boiler load is paid pid control module and is exported to soft manual operation device module, and soft manual operation device module is exported to outside executing agency---primary air fan outlet damper or frequency converter;
Described boiler load (main vapour pressure) pid control module parameter is set at: proportional band P1=20%~40%, and the time of integration, Ti1=10~30s exported rate of change=15%~25%; Bed temperature pid correction module parameter is set at: proportional band P2=40%~80%, the time of integration Ti2=20~52s, differential coefficient Kd2=1~2, derivative time Td2=10~20s, output rate of change=3%~7%, dead band=0.3%~0.5%; Ash concentration pid correction module parameter is set at proportional band P3=40%~80%, and the time of integration, Ti3=20~52s exported rate of change=3%~7%; Boiler load is paid the pid control module parameter and is set at: proportional band P4=40%~80%, the time of integration, Ti4=20~52s exported rate of change=0.1%~0.3%.
Described bed temperature set-point, ash concentration set-point are respectively the polygronal functions of boiler master vapour amount, ash concentration calculated value=burner hearth bottom pressure-furnace outlet pressure, heat correction coefficient=actual calorific value of coal/design calorific value of coal;
Described boiler load is regulated in the compound tandem loop, when actuator is two, adopts the balance module of two actuators; For the adjusting that wind once divides air door, be to divide a wind air door manual adjustments to the fixed position earlier, regulate the total air door of wind more automatically one time, realize that with this wind regulates automatically.
According to described method, boiler load (main vapour pressure) is regulated debug results: boiler load (main vapour pressure) dynamic process characteristic changes in the positive and negative 0.06 MPa scope of set-point, for the variation of (MCR) 5% at full capacity, overshoot 0.15 MPa, dynamic time is two process cycles.
Referring to Fig. 3, in technical scheme steps (3):
Described recirculating fluidized bed bed temperature is regulated and is adopted compound tandem loop regulative mode to be, recirculating fluidized bed bed temperature set-point signal, bed temperature measured value signal input bed temperature pid control module, boiler load set-point signal, boiler load measured value signal input main vapour pressure pid correction module, oxygen content of smoke gas set-point signal, oxygen content of smoke gas measured value signal input oxygen content pid correction module, the output of bed temperature pid control module, the output of main vapour pressure pid correction module, oxygen content pid correction module weighting summation is as paying pid control module set-point signal, coal-supplying amount or feeder revolution are as the measured value signal of paying pid control module, pay pid control module and export to soft manual operation device module, soft manual operation device module is exported to outside executing agency---feeder frequency converter or slip electric motor;
Being set at of described bed temperature pid control module parameter: proportional band P1=40~80%, the time of integration Ti1=20~52s, differential coefficient Kd1=1~2, derivative time Td1=10~20s, output rate of change=3%~7%; Being set at of main vapour pressure pid correction module parameter: proportional band P2=40~80%, the time of integration Ti2=20~52s, differential coefficient Kd2=3~7, derivative time Td2=10~20s, output rate of change=8%~12%, dead band=0.3%~0.5%; Oxygen content pid correction module parameter is set at: proportional band P3=80%~120%, and the time of integration, Ti3=40~80s exported rate of change=8%~12%; Paying the pid control module parameter is set at: proportional band P4=20%~40%, the time of integration, Ti4=10~30s exported rate of change=1%~5%.
Described bed temperature set-point, oxygen content of smoke gas set-point are respectively the polygronal functions of main steam flow amount;
Described bed temperature is regulated in the compound tandem loop, when actuator when being two or more, adopts balance module or a plurality of actuator distribution module (principle is seen Fig. 3) of two actuators.
According to described method, recirculating fluidized bed is regulated debug results and is: recirculating fluidized bed bed temperature dynamic process characteristic changes in the positive and negative 6 degree scopes of set-point, for the variation of (MCR) 5% at full capacity, and overshoot 16 degree, dynamic time is two process cycles.
With reference to Fig. 4, in technical scheme steps (4):
Described oxygen content is regulated and is adopted the tandem circuit type to be, flue gas oxygen content set-point signal, flue gas oxygen content measured value signal are imported main pid control module, pid control module is paid in main pid control module output, secondary air flow or the input of secondary wind pressure signal, pay pid control module and export to soft manual operation device module, soft manual operation device module is exported to outside executing agency---overfire air fan outlet damper or frequency converter, and coal-supplying amount feedovers;
Described oxygen content master's pid control module parameter is set at: proportional band P1=40%~80%, and the time of integration, Ti1=20~40s exported rate of change=3%~8%; Oxygen content is paid the pid control module parameter and is set at: proportional band P2=40%~80%, and the time of integration, Ti2=20~40s exported rate of change=0.2%~0.4%; Coal-supplying amount feedforward is set at: differential coefficient Kd3=10~30, derivative time Td3=20~40s.
Described oxygen content is regulated in the tandem loop, when actuator is two, adopts the balance module of two actuators; For the adjusting that the secondary air separating air door is arranged be, earlier secondary air separating air door manual adjustments arrived the fixed position, regulate the total air door of secondary wind more automatically, realize that with this secondary wind regulates automatically.
According to described method, flue gas oxygen content is regulated debug results and is: flue gas oxygen content dynamic process characteristic changes in positive and negative 0.8% scope of set-point, and for the variation of (MCR) 5% at full capacity, overshoot 1.4% handkerchief, dynamic time are two process cycles.
Described method to each monitor loop implementation classifying alarm is:
When mediation process surpasses common alarm limit, produce common acousto-optic hint and report to the police; Prescribe a time limit when mediation process surpasses emergency alarm, produce urgent sound and light alarm, require operating personnel to take corresponding measure (prompting operation), avoid occurring accident; When mediation process breaks down, produce emergency alarm, require regulating system to take to force automatically to be cut to manually, or press the broken line override action (automatic switchover) of design in advance, avoid the accident extension.