Brochure

Compressor Antisurge Control Valve
The efciency and availability of a plant’s compressors
both have a direct impact on the protability of the facility.
Unexpected downtime of any of the plant’s refrigerant
loops will lead to reduced LNG production and the
potential for hefty contractual penalties. Compressors also
represent some of the most valuable pieces of equipment
within an LNG facility. Not only will damage to these assets
cause unexpected production downtime, it can also lead
to very costly repairs.
Antisurge valves provide recycle ow to each stage of
the multi-stage compression trains that are common to
liquefaction processes. During startup and commissioning,
the valve provides throttling control to recycle a portion
of the discharge ow as the compressor is brought up to
capacity. During the normal operation of the plant, the
antisurge valve will remain closed or slightly open to allow
for a small portion of the discharge to be recycled. When
closed, it is important that the valve provides tight shutoff
to prevent unwanted recycle ow.
The primary purpose of the antisurge valves is to protect
the most critical and expensive pieces of equipment in the
plant, the compressors. During a surge event, the valve
must open in one to two seconds to recycle the discharge
ow back around to the suction side of the compressor.
Failure of the valve to react quickly to the antisurge
controller can result in severe damage to the impellers of
the compressor from the reversed ow of a surge event.
An LNG facility in Brunei needed
to replace all of its existing
propane and mixed refrigerant
compressor antisurge valves.
After seeing a demonstration of
the Fisher optimized antisurge
valve, the plant turned to
Emerson who has proven its
ability to understand and meet stringent valve performance
criteria.
The 25 existing valves were replaced by NPS 12 through NPS
30 Fisher optimized antisurge valves.
•The valves open in less than two seconds, as well as meet
stringent closed-loop control criteria.
•The measured linearity is less than 0.75%, and the valves
have minimal overshoot in the open and closed directions.
• It often requires about 12 hours to tune a non-Fisher
antisurge valve. With its fewer accessories and diagnostic
capabilities, tuning time for a Fisher optimized antisurge
valve takes only minutes.
All this added up to an antisurge valve solution that helped
to protect compressors and increase process efficiency.
Scan this code to learn more about
the Fisher optimized antisurge
solution designed specifically for
antisurge applications.
A Case-In-Point
16 | Fisher
®
LNG Liquefaction Solutions