General Objectives and Benefits of an Advanced Process Control System for a Refinery

General Objectives and Benefits of an Advanced Process Control System for a Refinery

By

Neda Felorzabihi, David H. Jones and Javier Vazquez-Esparragoza

KBR Technology

 

Abstract

The objective of the paper is to present some of the basis of design for the Advanced Process Control (APC) applications to be implemented in a typical Oil Refinery, and a brief survey summary of APC Potential benefits for applicable units in the refinery and also it is intended to provide a common understanding between all the project team members participating in an APC project.

Advanced Process Control is a critical component of “best-in-class” operation, enabling significant improvements in asset utilization and energy consumption for most processes. Specifically, APC is any process control system application that has functions beyond those commonly associated with basic or regulatory controls.

Advanced Process Control could be defined as multivariable, model-predictive control (MVC) consisting of a suite of applications that uses either linear or non-linear dynamic models to design, implement and maintain MVC strategies in order to effectively improve the plant stability, increase plant safety and maximize plant profitability. 

In this article, the general functionality is presented for an APC system design developed for a pre-FEED (Front End Engineering Design) phase of a 400,000 barrels per day (BPD) grassroots Refinery Complex.  

The refinery complex was separated into several units or operational areas for APC application as listed below:

µ   CDU, crude distillation unit

µ   VDU, vacuum distillation unit

µ   Naphtha stabilizer

µ   NHT, naphtha hydrotreater

µ   Continuous catalytic reformer unit

µ   Isomerization unit

µ   Hydrocracker  unit

µ   Distillate Hydrotreater

µ   Other units

Not every operational area would have APC applications and some of them would have more than one controller.   

As an example of general control Philosophy, the following items are included in the paper:

µ   APC General Control Objectives

µ   APC General Control Strategy

µ   Typical Benefits per plant and global

The estimated potential benefits in  dollar amount from the APC applications is included in the scope of work and the expected cost for a refinery wide APC is presented. Proper implementation and maintenance would be necessary to achieve and maintain these benefits.