|
Tower – Vacuum Systems
TRACERCO Diagnostics™ Helium Leak Study
 Vacuums
are achieved by use of steam aspirators and vacuum pumps. The operation
of these devices to produce a vacuum is costly, just as is the use of
steam for reboilers. If there is an atmospheric leak into the process,
these devices have to be pushed to greater effort to maintain appropriate
vacuums, which increases the cost of operation. Sometime, the devices
cannot meet the demands and appropriate vacuums cannot be maintained,
reducing the efficiency of the separation process. Air ingress can occur
in many places. Every flange, threaded fitting, sight glass, block valve
or valve stem is a potential point for an air leak. Even areas of severe
corrosion or welds have been detected as points of air ingress.
A TRACERCO Diagnostics™ Helium Leak Study is an effective approach
to identifying leaks in this type of system. An ultra sensitive portable
mass spectrometer is used to analyze the exhaust from the steam ejectors.
The arrangement of the sampling process varies according to the piping
of the exhaust, but the mass spec is arranged to continuously draw vapor
in from the steam ejector exhaust. One crew member monitors the readout
from the mass spec during the testing. The second crew member is equipped
with a small bottle of helium, mounted with a trigger valve. This crew
member starts near the bottom of the vessel and squirts a small amount
of helium near a flange, valve, or other item where air could possibly
be drawn into the system. As he does this, he marks the item to indicate
that it has been tested. Depending on the size of the vessel and the distance
from the leak point to the mass spec sampling point, several minutes may
be required for helium to pass through the vessel and be detected by the
mass spec. When the technician monitoring the mass spec identifies a positive
indication, he will have the other crew member back track the tested items
until they can identify the location of the leak.
 DOWNLOADS
|
|
 |
