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Incorporation of Advanced Process Control Technology into Conceptual Process Design

IP.com Disclosure Number: IPCOM000218588D
Publication Date: 2012-Jun-05
Document File: 5 page(s) / 268K

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Page 01 of 5

Incorporationof Advanced ProcessControl Technology

Into Conceptual Process Design

W. B. Stewart and T. B. Challand

The M. W. KelloggCompany
Houston,Texas

The design of a chemical process should include control system and operability analysis. These elements should be integrated into the conceptual process design in an objective, systematic fashion. This goal is best achieved by performing this work as an integral part of the design work, rather than as an afterthought.

Objective design of the control system and analysis of the process operability require state-of-the-arttools and techniques which have been developed largely for advanced process control study. This paper addressesthe use of these tools and techniques in a timely fashion to ensure the operability of a processand to maximize its performance.

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Page 02 of 5

Incorporation of Advanced Process Control Technology

Into Conceptual Process Design

W. B. Stewart and T. B. Challand

The M. W. Kellogg Company
Houston, Texas

Introduction

The design of chemical and petrochemical process plants involves many factors. Some of these factors are objective, such as capital expense, operating costs, availability of utilities, etc. These factors are generally well understood and rigorously calculated.

Traditionally, operability analysis and control system design have been influenced heavily by subjective criteria. For reliability and long-term profitability of a process, the operability is as important as the traditional objective factors. After all, an "optimized" process design is useless if the plant cannot be controlled. Therefore, these elements should be integrated into the conceptual process design in an objective, systematic fashion.

In order to shift operability analysis and control system design to the list of objective design factors, objective criteria must be determined and satisfied. These criteria and the tools with which conformance is established have historically been related to advanced process control study. This paper addresses the technoloQynecessary for objective operability analysis and control system design criteria to be satisfied during the conceptual design phase of a process. This paper is not intended to provide answers. Rather, its focus is to make the case for incorporating objective operability analysis and control system design criteria into the conceptual design of process plants.

Operability Analysis

A traditional procedure is to overdesign process equipment to empirically account for the so-called "worst case scenario". Of course, this tends to dampen dynamic responses, but is not always the correct course of action. There are situations where this is exactly the wrong thing to do.

An operability analysis should be based upon objective criteria to determine the stable area of operation. A complicatingfactor is uncertainty. Oftentimes, the process design team is given a design basis, but not the ranges that influential process parameterscan take on. Fo...