Once-through Circulating Fluidized Bed Boiler Control Design with the Dynamic Relative Gain Array and Partial Relative Gain

Abstract

Combustion power plants currently face major performance challenges, which require robust control design methods. Extensive relative gain analysis was conducted in this paper to generate plantwide control structures for a full-scale once-through circulating fluidized bed boiler. No such study has been reported before for steam boilers. The partial relative gain was employed to generate decentralized control structures based on integral controllability with integrity. The approach provided feasible control structures and verified that basic turbinefollowing boiler control is preferable in terms of controllability. The steady-state results were extended with the dynamic relative gain array for higher frequencies, which revealed that boiler-following control becomes feasible for faster disturbances. The results highlight the complex interactions between steam pressure and output electrical power control, as well as the loop interactions caused by the feedwater flow in the once-through steam path.

Integrated control and process design for improved load changes in fluidized bed boiler steam path

“…The ICPD optimization objective was constructed as a combination of desirable qualities for the closed-loop load change response, resulting in the weighted sum ( 13)- (19). The individual terms were scaled by dividing them with their values for the nominal boiler design and control parameters.…”

On the Flexible Operation of Supercritical Circulating Fluidized Bed: Burning Carbon Based Decentralized Active Disturbance Rejection Control

“…To evaluate the control performance, the integrated absolute error (IAE) index is used, IAE = T 0 |e(t)|dt (15) where e(t) is the tracking error of the controlled variable. IAE tends to produce responses with less sustained oscillation.…”

“…The proportional-integral-derivative (PID) control is the most widely used control strategy in real control engineering. Hultgren and Hao et al analyzed the relative gain and designed a decentralized PID control structure for the CFB unit [15,16]. The controllers in [16] were devised based on desired dynamic equation (DDE) while an heuristic algorithm was used to optimize the PID controllers for the CFB unit in [17].…”