SEPTEMBER
2014
LNG
INDUSTRY
61
H
igh fidelity dynamic simulation enables engineers
to ‘test drive’ turbomachinery systems, studying
how equipment and controls will integrate and how
processes will interact. Simulation helps avoid costly errors and
improves efficiency. It facilitates debugging the control system
prior to ever going live, thereby saving time on commissioning
and becoming a valuable tool for training operators. Analysing
real-life case studies, this article describes how using high fidelity
dynamic simulation to ‘test drive’ turbomachinery systems
reduces costs, saves time, improves safety and increases
availability.
Reduce costs
Dynamic simulation helps avoid costly design errors by verifying,
for example, that valve and vessel sizes and equipment
configurations are correct at an early stage (when changes can
be made at minimum cost). By allowing engineers to verify that
the overall systemwill perform as designed, dynamic simulation
models can have a big impact on the bottom line expenses.
For instance, one refinery plant in Canada used dynamic
simulation to test transient scenarios for an electric motor trip on
a four-stage compressor. In this situation, all stages were driven
by an electric motor and involved cold-gas recycle. The results of
the simulation showed that the first stage experienced surge
regardless of the anti-surge valve size. It also showed that after
the trip, the operating point in the fourth stage of compression
moved rapidly towards a stonewall regime. Pressure in the fourth
stage was insufficient to supply necessary flow to the anti-surge
valve (see Figure 1).
Using dynamic simulation, engineers at this plant were able
to find alternative solutions. Since the control logic monitors the
operating point distance from the surge line – where a negative
surge margin means that the compressor is in surge – simulation
Take
Hector Buchelly,
Schneider Electric,
USA,
looks at how
dynamic simulation
can boost
turbomachinery
system capabilities.
control
ntrol
