Establishment of normal operating zone models by boundary points for CSTR-DC-recycle chemical processes

doi:10.1016/j.cjche.2025.03.012

Abstract

Abstract: Integrated continuous stirred-tank reactors and distillation columns with recycle (CSTR-DC-recycle) are essential components in chemical processes. This paper proposes a method to establish a normal operating zone (NOZ) model to represent allowable variations of the CSTR-DC-recycle chemical processes. The NOZ is a geometric space containing all safe operating points of the CSTR-DC-recycle chemical processes, so that it is an effective model for process monitoring. The novelty of the proposed method is to establish the NOZ model based on boundary points. The boundary points make it possible to capture the actual geometric space irrespective of the space shape. In contrast, existing methods represent the NOZ of processes by fixed mathematical models such as ellipsoidal and convex-hull models; they are not suitable for the CSTR-DC-recycle chemical processes whose NOZs cannot be exactly defined by fixed mathematical structures. Simulated case studies based on Aspen Hysys software are given to illustrate the proposed method.

Key words: Chemical processes, Grey-box model, Normal operating zone, Bayesian estimation, Model uncertainty measurement, Boundary points

摘要： Integrated continuous stirred-tank reactors and distillation columns with recycle (CSTR-DC-recycle) are essential components in chemical processes. This paper proposes a method to establish a normal operating zone (NOZ) model to represent allowable variations of the CSTR-DC-recycle chemical processes. The NOZ is a geometric space containing all safe operating points of the CSTR-DC-recycle chemical processes, so that it is an effective model for process monitoring. The novelty of the proposed method is to establish the NOZ model based on boundary points. The boundary points make it possible to capture the actual geometric space irrespective of the space shape. In contrast, existing methods represent the NOZ of processes by fixed mathematical models such as ellipsoidal and convex-hull models; they are not suitable for the CSTR-DC-recycle chemical processes whose NOZs cannot be exactly defined by fixed mathematical structures. Simulated case studies based on Aspen Hysys software are given to illustrate the proposed method.

关键词: Chemical processes, Grey-box model, Normal operating zone, Bayesian estimation, Model uncertainty measurement, Boundary points

Poku Gyasi, Jiandong Wang, Mengyao Wei, Hao Jing. Establishment of normal operating zone models by boundary points for CSTR-DC-recycle chemical processes[J]. Chinese Journal of Chemical Engineering, 2025, 85(9): 140-157.

Poku Gyasi, Jiandong Wang, Mengyao Wei, Hao Jing. Establishment of normal operating zone models by boundary points for CSTR-DC-recycle chemical processes[J]. 中国化学工程学报, 2025, 85(9): 140-157.

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