Online Closed Loop Pipeline Control by Transient Computer Model

Pipelines transporting different grades of crude oil or products usually operate with fixed setpoints for pressure limit switches and relief valves. These setpoints are calculated for a worst case condition as maximum flow rate combined with a sequence of batches of high viscosity ratio, etc. Under standard operating conditions, this worst case condition never occurs, so the setpoints restrict operating flexibility. With a transient simulation model it is possible to calculate these setpoints for actual hydraulic conditions on-line. Special attention has been paid to fail-safe operation of this on-line model and setpoint calculation. Our approach avoids all the problems linked to software in fail-safe applications and may be used for other applications of on-line simulation too. This concept has been successfully applied to a pipeline system in Austria, the AWP-Pipeline. With the new technology, substantial savings in energy costs (1–2 pump stations out of 11) as well as increased maximum throughput are possible now.