Liquid Pipeline Capacity Optimization Through Pressure Control Available to Purchase

In 2006/2007 Enbridge Pipelines undertook a pressure control optimization program as part of an overall effort to maximize throughput on a 34^″ batched heavy crude pipeline. Higher throughputs required simultaneous operation of both pump units at intermediate stations. This mode of operation had not been previously achieved on a reliable basis due to the occurrence of line instabilities. Pressure control optimization procedures developed by Enbridge and control industry partners over the past 5 years were employed. Program scope included review and optimization of pressure control systems at 24 pump stations and 3 delivery sites. A preliminary review of pressure control valves established their suitability for anticipated service conditions. No other significant equipment purchases were required to execute the project. Program results are: • Intermediate stations are now reliably operated with both pump units simultaneously engaged; • A minimum 3.5% increase in pipeline sustained capacity is attributed by Enbridge to the pressure control optimization efforts; • PCV pressure drop reductions were achieved at most mainline pump stations resulting in greater than $500,000 (US) per year in pumping energy savings; • A 32% reduction in delivered batch size over/short volumes was achieved at one delivery site; • Operators report a significant increase pipeline reliability, with historical data demonstrating a 50% reduction in one indicator of operator burden; • Program costs were recovered in less than one year of operation. Similar pressure control optimization efforts are currently being undertaken on other pipelines within Enbridge’s network.