MAXIMISE PRODUCTION VIA DCS LEVEL CONTROL SCHEME

Abstract

In PETRONAS LNG Complex, the Acid Gas Removal Unit (AGRU) stability is crucial to ensure maximisation of LNG production. Foaming in Absorber Column, C-91101 is a commonly encountered problem in MLNG TIGA LNG Trains. Severe foaming incident results in liquid carry-over to the downstream unit and cause total LNG Train trip as per safeguarding. As a countermeasure, a new control scheme residing at the DCS level was specially designed and commissioned in both Train 7 & 8. This is an integrated initiative between Advanced Process Control (APC), Technologist, and Operation team to support production maximisation and sustenance. Operated with 100% uptime, this control scheme ensures standardized action to be taken and provides overall dynamic stability at AGRU, allowing for production maximisation without jeopardizing the absorber column’s tray integrity. This initiative leads to LNG Big Cargo Equivalent (BCE) loss reduction from 0.9 BCE (2015) to an average of 0.09 BCE (2016 – 2019), which is equivalent to a 90% improvement.

Keywords: Advanced Process Control (APC), DCS, DCS Level Control Scheme, Foaming, Liquefied Natural Gas (LNG)