FLUID HANDLING
STEAM EQUIPMENT EXPERTS
MAGNETROL
THE
CHALLENGES
OF ACCURATE
INTERFACE
MEASUREMENT
Interface or multiphase level measurements
exist throughout the oil & gas streams as well
as petrochemical. While level measurement
technologies have come a long way
in effectively measuring liquids and solids,
multiphase level measurement continues
to be the biggest challenge and opportunity
that exists today to which there is no perfect
technology. However, experience has shown
that process optimization and increased
uptime can still be achieved in many separator
applications through reliable, best-in-class,
level technology.
Magnetrol® recognizes that interface
measurement is a key concern for these
industries, as well as many others. With
that in mind, MAGNETROL has developed
a white paper addressing the challenges and
considerations around interface measurement
and currently available technologies for
process optimization.
THE BASICS OF INTERFACE
In the oil & gas and petrochemical industries,
the need for reliable interface measurement
arises whenever immiscible liquids, those
incapable of mixing, reside within the same
vessel. The lighter medium rises to the top
and the heavier settles at the bottom. In oil
production, for example, water or steam
is used to extract oil from a well. Well fluids
then route to production separators where
they settle into their primary constituents as
a hydrocarbon over water interface.
Interfaces can form between liquids and
solids, liquid and foam, and liquid and gas;
but the emphasis here will be concentrated
on liquid/liquid interface (often with a vapor
space above the top/lighter liquid). Immiscible
liquids meet along an interface layer where
they undergo some amount of emulsification.
This emulsion layer (also referred to as a “rag”
layer) may form a narrow, distinct boundary,
but more frequently it is a broader gradient
of the mixed liquids. Generally, the thicker the
emulsion layer, the greater the measurement
challenge.
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PECM Issue 38
INTERFACE MEASUREMENT
CHALLENGES
While monitoring the top, or total level,
is critical for safety and overfill prevention,
knowing the level of an interface
is necessary for maintaining product quality
and operations efficiency. If there is water
in oil that is not separated effectively (water
carryover), then this can induce processing
problems, equipment failures and unplanned
shutdowns. If there is oil in water (oil
extraction), then there can be production
loss, environmental fines, penalties and forced
shutdowns.
Of all the level switches and transmitters
available, only a handful are suitable for reliable
interface measurement. The leading interface
measurement technologies include guided
wave radar (GWR), buoyancy-based displacers
and magnetostrictive, RF capacitance, nuclear/
gamma radiation and thermal dispersion.
Ideally, the technology utilized for interface
applications does not have to differ from
other level instruments installed at the facility
in order to maintain familiarity with users.
Standardizing on a technology helps reduce
training, installation & commissioning,
maintenance and downtime.
MORE INFORMATION
To learn more about interface measurement
challenges and the technologies available
to more accurately monitor interface,
download the interface white paper.
The white paper covers:
• interface challenges;
• case studies in Oil & Gas and Petrochemical;
•
comparison of level technologies for
interface measurement; and
• the future of reliable interface measurement.
interface.magnetrol.com