Systematic Control Structure Evaluation of Two-Stage-Riser Fluidized Catalytic Pyrolysis Processes

摘要

Control structure selection plays an important role in achieving an effective control system. Through the application of open-loop and closed-loop steady-state multiplicities, the primary goal of this paper is to obtain the best control structure from candidates selected based on heuristic reasoning for a demonstration Two-Stage-Riser Fluidized Catalytic Pyrolysis (TSRFCP) process which can maximize propylene yield without any significant losses in gasoline/diesel yields. Steady state multiplicity analysis can not only elucidate the relationships between potential manipulated variables and controlled variables over a large operational horizon but can also identify the perfect control action for tackling uncertainties in each control structure. It is illustrated that output temperatures from the two risers and the regenerator controlled by two regenerated catalyst flow rates and the cooling water flow rate, respectively, which have the best controllability characteristics and most superior dynamic behavior, are the most suitable control structure for further control system design of the studied process.