Model-free adaptive control of supercritical circulating fluidized-bed boilers
AssigneeGeneral Cybernation Group Inc.
InventorsGeorge Shu-Xing Cheng, Steven L. Mulkey
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Abstract
A novel 3-Input-3-Output (3×3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7×7) MFA control system is also described for controlling a combined 3-Input-3-Output (3×3) process of Boiler-Turbine-Generator (BTG) units and a 5×5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.
Claims16
A system comprising a Circulating Fluidized-Bed Boiler (CFB) combustion process with 5 inputs and 5 outputs to be controlled by a multivariable Model-Free Adaptive (MFA) control system, wherein the process having 5 process inputs as manipulated variables, 5 process outputs as the process variables to be controlled, 5 main-processes H11, H22, H33, H44, H55, and 20 sub-processes H21, H31, . . . , H45 according to the following table:
- Process Outputs - Process
- Variables to be Controlled
- Process Inputs -
- Bed
- Excess
- Negative
- Bed
- Manipulated
- Temp
- O2
- Pressure
- Thickness
- Firing Rate
- Variables
- (TB)
- (O2)
- (PN)
- (DB)
- (RF)
- Primary Air
- H11
- H21
- H31
- H41
- H51
- (FP)
- Secondary Air
- H12
- H22
- H32
- H42
- H52
- (FS)
- Exhaust Air
- H13
- H23
- H33
- H43
- H53
- (FE)
- Slag Disposal
- H14
- H24
- H34
- H44
- H54
- (FD)
- Coal Feed
- H15
- H25
- H35
- H45
- H55
- (FC).
A 3-Input-3-Output (3×3) Fuel-Air Ratio Controller comprising a 3-Input-3-Output (3×3) MFA Controller, three signal adders, three calculation blocks, one scaling block, a fuel flow signal uf(t) as an input, three setpoint signals r1(t), r2(t), r3(t), three process variables to be controlled y1(t), y2(t), y3(t), three error signals c1(t), c2(t), c3(t), and three controller output signals u1(t), u2(t), u3(t);
- wherein the 3×3 MFA Controller having three output signals ua1(t), ua2(t), ua3(t), and the control output signals of the (3×3) Fuel-Air Ratio Controller being calculated substantially of the form:
- vf(t)=L[uf(t)],
- u1(t)=a1vf(t)+Δua1(t),
- u2(t)=a2vf(t)+Δua2(t),
- u3(t)=a3vf(t)+Δua3(t),
- where uf(t) is the fuel flow signal, L(.) is a scaling function to scale the fuel flow signal uf(t) to a control signal vf(t) in the range of 0 to 100, Δua1(t), Δua2(t), Δua3(t) are controller output incremental signals from the 3×3 MFA Controller, and a1, a2, a3 are fuel-air ratio parameters.
A 3-Input-3-Output (3×3) Fuel-Air Ratio Controller comprising a 3-Input-3-Output (3×3) Controller, three signal adders, three calculation blocks, one scaling block, a fuel flow signal uf(t) as an input, three setpoint signals r1(t), r2(t), r3(t), three process variables to be controlled y1(t), y2(t), y3(t), three error signals e1(t), e2(t), e3(t), and three controller output signals u1(t), u2(t), u3(t);
- wherein the 3×3 Controller having three output signals ua1(t), ua2(t), ua3(t), and the control output signals of the (3×3) Fuel-Air Ratio Controller being calculated substantially of the form:
- vf(t)=L[uf(t)],
- u1(t)=a1vf(t)+Δua1(t),
- u2(t)=a2vf(t)+Δua2(t),
- u3(t)=a3vf(t)+Δua3(t),
- where uf(t) is the fuel flow signal, L(.) is a scaling function to scale the fuel flow signal uf(t) to a control signal vf(t) in the range of 0 to 100, Δua1(t), Δua2(t), Δua3(t) are controller output incremental signals from the 3×3 Controller, and a1, a2, a3 are fuel-air ratio parameters.
A control system, comprising:
- a) a Circulating Fluidized-Bed Boiler (CFB) combustion process having process inputs comprising one or more of Primary Air, Secondary Air, Exhaust Air, Slag Disposal and Coal Feed as manipulated variables and having process outputs comprising one or more of Bed Temperature, Excess O2, Furnace Negative Pressure, Bed Thickness, and Firing Rate as the process variables to be controlled;
- b) a 3-Input-3-Output (3×3) Fuel-Air Ratio Controller whose outputs manipulate the Primary Air, Secondary Air, and Exhaust Air of the CFB combustion process to control Bed Temperature, Excess O2, and Furnace Negative Pressure;
- and
- c) a Coal Feed or Fuel Flow setpoint being used as an input to the 3×3 Fuel-Air Ratio Controller.
A control system, comprising:
- a) a combined 5-Input-5-Output (5×5) Circulating Fluidized-Bed Boiler (CFB) combustion process and 3-Input-3-Output (3×3) Power-Pressure-Temperature (PPT) process of a Boiler-Turbine-Generator (BTG) unit, where the Firing Rate of the CFB process is an input to the PPT process;
- b) a Primary Air control loop, Secondary Air control loop, and a Coal Feed control loop;
- c) a Throttle Valve and Steam Flow sub-system;
- d) a Water Flow sub-system;
- and
- e) a 7-Input-7-Output (7×7) Model-Free Adaptive (MFA) control system arranged to control one or more of Power, Steam Pressure, Steam Temperature, Bed Temperature, Excess O2, Furnace Negative Pressure, and Bed Thickness of the combined CFB combustion process and PPT process.
A control system, comprising:
- a) a combined 5-Input-5-Output (5×5) Circulating Fluidized-Bed Boiler (CFB) combustion process and 3-Input-3-Output (3×3) Power-Pressure-Temperature (PPT) process of a Boiler-Turbine-Generator (BTG) unit, where the Firing Rate of the CFB process is an input to the PPT process;
- b) a Primary Air control loop, Secondary Air control loop, and a Coal Feed control loop;
- c) a Throttle Valve and Steam Flow sub-system;
- d) a Water Flow sub-system;
- and
- e) a 7-Input-7-Output (7×7) control system arranged to control one or more of Power, Steam Pressure, Steam Temperature, Bed Temperature, Excess O2, Furnace Negative Pressure, and Bed Thickness of the combined CFB combustion process and PPT process.
Dependencies are inferred from the claim text.