A recent paper by Ipcos’ Edwin Weetink presented at a Petronas-sponsored conference earlier this year investigates how process control best practices help sustain operational excellence. The paper covers control optimization in Ammonia and Urea plants but has implications for oil producers and refiners. Process industries need to optimize operations in the face of constantly changing requirements, variations in feedstock quality and operator interventions. Relatively small short term disturbances can have a big impact on longer term operations. Best practices in automated control are reducing the frequency of ‘excursions’ resulting from disturbances or sub-optimal operator intervention. Examples of best practices include optimized base layer controls to complete ‘auto-pilots’ for the entire plant.
Weetink’s thesis is that operators’ reactions to alarms and excursions frequently make for suboptimal setpoint changes that drive the process away from optimal, leading to reduced production rates. Control acts at two levels—‘base layer’ control in PID loops providing second-by-second control of flow, temperature and pressure and ‘advanced process control’ (APC) which acts as an ‘auto-pilot’ for the plant. The full paper is available on www.oilit.com/links/1005_14 (log on required).
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