This paper discusses the application of the plantwide control design procedure of Skogestad [Skogestad, S. (2004a). Control structure design for complete chemical plants. Computers and Chemical Engineering, 28, 219–234] to the ammonia synthesis process. Threemodes of operation are considered: (I) given feed rate, (IIa) maximum throughput, and (IIb) “optimized” throughput. Two control structures...

In this work a new systematic and generalized strategy to solve the MIMO plantwide control problem is proposed. The methodology called Minimum Square Deviation (MSD) considers several points such as the optimal sensor location (OSL) based on the sum of square deviation (SSD) and the control structure selection (CSS) based on net load evaluation (NLE) problems simultaneously. Particularly, this ...

Design and control of recycle systems must be integrated at an early design stage. By placing together the pieces of the design puzzle we developed a novel methodology that allows the screening and selection of feasible integrated designs at an early stage. The generic structure is the Reactor-Separator-Recycle (R-S-R) system. Multiple steady states are possible and a minimum reactor volume is ...

Plantwide control (PWC) is an inherently complex task, which why systematic guidelines and step-wise procedures are necessary to identify proper pairings. Several different methodologies for the development of PWC structures have been proposed over years, trying balance field between formal methods, practicality, heuristics. The Integrated Framework Simulation Heuristics (IFSH) by Konda et al. ...

Accurate detection and isolation of faults is a critical component of a reliable and efficient plantwide faulttolerant control system. In a recent work (Ohran et al. AIChE J. 2008, 54, 223), we demonstrated that using a nonlinear controller to enforce a specific structure in the closed-loop system allows data-based detection and isolation of certain faults that would otherwise not be isolable u...

The paper discusses distillation column control within the general framework of plantwide control. In addition, it aims at providing simple recommendations to assist the engineer in designing control systems for distillation columns. The standard LV-configuration for level control combined with a fast temperature loop is recommended for most columns.

Second generation biorefineries transform lignocellulosic biomass into chemicals with higher added value following a conversion mechanism that consists of: pretreatment, enzymatic hydrolysis, fermentation and purification. The objective of this study is to identify the optimal operational point with respect to maximum economic profit of a large scale biorefinery plant using a systematic model-b...