U-model enhanced dynamic control of a heavy oil pyrolysis/cracking furnace

Quanmin Zhu,Pritesh Narayan,Shuzhan Zhang,Dongya Zhao

doi:10.1109/jas.2017.7510847

Abstract

This paper proposes a case study in the control of a heavy oil pyrolysis U+002F cracking furnace with a newly extended U-model based pole placement controller U+0028 U-PPC U+0029. The major work of the paper includes: 1 U+0029 establishing a control oriented nonlinear dynamic model with Naphtha cracking and thermal dynamics; 2 U+0029 analysing a U-model U+0028 i.e., control oriented prototype U+0029 representation of various popular process model sets; 3 U+0029 designing the new U-PPC to enhance the control performance in pole placement and stabilisation; 4 U+0029 taking computational bench tests to demonstrate the control system design and performance with a user-friendly step by step procedure.

Highlights

The introduction consists of five sub-sections: a review of existing representative approaches in modelling of oil cracking furnaces, a review of control approaches to such furnace operations, a brief overview of U-model based control system design and, with reference to the critical survey/analysis, justifying the necessity of the study and listing the major contributions of the current work, and summarising the remaining sections of the study.1.1 Modelling of heavy oil cracking furnace Cracking feedstock, heated and conveyed into the furnace tube of the radiant section of a furnace, absorbs heat from the external radiation chamber, causing heating and cracking
The U-model based pole placement controller (U-PPC) design procedure is specified for designing the control of the temperature on the outer wall of the reaction tube in the heavy oil pyrolysis/cracking furnace
4.2 design of U-model based stabilised controller (U-SC) It should be noted that the precondition for designing a pole placement controller is that the process is stable at least within the operational region

Summary

Introduction

The introduction consists of five sub-sections: a review of existing representative approaches in modelling of oil cracking furnaces, a review of control approaches to such furnace operations, a brief overview of U-model based control system design and, with reference to the critical survey/analysis, justifying the necessity of the study and listing the major contributions of the current work, and summarising the remaining sections of the study. It should be noted that the control system design approach developed in the study is fundamentally different from a Jacobian linearization for small range operation, which is the base for almost all other linear control system design approaches This is the first study of issues associated with control of conditionally stable nonlinear process within the U-model framework, which has not theoretically proved the controller, but heuristically formulated and numerically demonstrated with the bench test example. Remark 3: Hammerstein models can be used to describe many different processes, especially if their main nonlinear behaviour is induced by actuators such as valves, an essential component for controlling of fluid in flow and pressure in many chemical engineering applications (Huang and Wang 2012) It has been observed (Zhang, Li, and Chen 2008) that this model structure has been successfully applied to chemical processes such as heat exchang, distillation, and biological processes. It should be noted that even NARMAX models have been well studied in the domain of system identification, it has almost not been systematically study in control system design due to the model structure not being a class of control oriented prototype

U-model enhanced controller design Assumption

Findings

Conclusions