Hydrocarbon Processing - December 2021 - GP-32

PLANT OPTIMIZATION
FIG. 3. Without intelligent throughput optimization control, the process conditions are crossing
the hydrate curve.
Case studies. A processor shipping propane
entrained in a natural gas pipeline in
North America had conservatively based
calculations on the lowest gas temperature
of about 20°F (-7°C). This helped
them gauge how much propane could be
injected into the natural gas before liquid
could form and collect in the low points
of the pipelines, and thereby threaten
compressor performance.
However, the temperatures rarely
sank so low, which meant they were missing
the opportunity to earn more yield.
Since implementing the new simulation
software, the company can use real-time,
composition-based physical constants
for closed-loop control and automatically
set the propane injection limit factoring
in the temperature. As a result, the producer
can ship approximately 20% more
propane throughout 90% of the year.
In another case, facility operators
FIG. 4. The process conditions are so close to the vapor saturation curve that little if any liquid is
forming, minimizing the effectiveness of the separator.
ran heaters around the clock to keep hydrates
from forming in their natural gas
piping. Throughput optimization simulation
software, however, pinpointed
the risks of hydration forming as next
to none. This allowed the operators to
reduce the use of heaters from 100% of
the time to only 5%, saving more than $
1 MM/yr in fuel costs.
FIG. 5. With closed-loop intelligent throughput process control, the process is operating at an
optimal point in the phase envelope for liquid dropout.
process is operating at an optimal
point in the phase envelope
for liquid dropout.
Real-world results. By gaining real-time
insights from the two-phase envelope,
producers can:
* Increase throughput-
By understanding where the
process is operating in relation
to the phase envelope and hydrate
curves, processes can be tuned
to produce more output.
* Increase reliability-
By understanding the phase
envelope and hydrate curve,
facilities can be operated to avoid
mixed-phase operation and avoid
hydrates, which leads to stable
operation and less wear and tear
on equipment.
* Reduce energy use-
By understanding hydrate
temperatures and phase
envelopes, heater, refrigeration
and compression use can be
optimized, reducing energy use.
* Reduce emissions-
Understanding process states
results in a more stable facility,
reducing emissions generated
during instabilities and providing
the inputs to optimization
for minimum emissions.
32 NOVEMBER/DECEMBER 2021 | GasProcessingNews.com
Takeaway. As gas pipeline and facilities
operations face mounting demands to
increase throughput and reliability, producers
are looking for pragmatic, cost-effective
ways to improve production and
efficiency. By using real-time automated
tuning control solutions, producers can
more effectively control processing fluids,
while mitigating risks to processes,
equipment and personnel. As a result,
producers can maximize capacity use
and better maintain operational safety
and total costs. GP
ROSS OTTO focuses on pipeline
control and optimization as a
Global Engineering Manager and
packaged solution champion at
Sensia, a joint venture between
Rockwell Automation and
Schlumberger. Mr. Otto's leads
an innovation team adapting existing technologies
to specific industry challenges in optimization,
maintenance and emissions reduction. He previously
served as a technical specialist and program manager
for Rockwell Automation. Before coming to the
automation world, Mr. Otto spent many years designing
and delivering pipeline SCADA, leak detection and
optimization systems. With more than 35 yr of
experience, he is a trusted source for pipeline
automation and optimization in the oil and gas industry.

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Hydrocarbon Processing - December 2021

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