Following new plant construction or routine maintenance, process plant integrity will frequently require verification
particularly for those process units handling high value or
high toxicity gas. Process leaks can occur from many
different sources such as poorly mating flanges, gasket
failure, insufficient tightening, relief valves passing or
bonnet seals leaking.
Helium Leak Detection Service
Following the pressure test that proves the mechanical
integrity of all the components, Air Products fills the system
to working pressure with a mixture of 99% nitrogen and 1%
helium. The helium is used as a trace gas and should a leak
be present in any part of the system it can easily be traced
and quantified using a portable mass spectrometer and
sampling probe.
Acceptable leaks are normally set in the range
50-100 SCF (1.5 - 3.0m³) per year. If greater sensitivity
is required, leaks down to 1 SCF (0.03m³) per year can
be traced.
In addition, APEX Industrial Gas Services is able to perform
valve integrity tests with nitrogen and ensure that all
emergency shutdown and equipment isolation valves are
leak tight. Our technicians are skilled in the use of ultrasonic
detectors for locating passing valves.
Nitrogen and helium are both dry inert gases so the system
is left totally leak-tight and ready to accept hydrocarbons or
other process streams.
Air Products is able to offer the services of a specialist team
that can pre-engineer alongside your own commissioning
engineers, a procedure customised to the requirements of
your project.
Shutdown de-commissioning and
re-commissioning
Process unit shutdowns usually require detailed programme
planning to meet a very tight schedule. Air Products
engineers will work closely alongside your process operators
to establish the most cost-effective means to remove all
hydrocarbons or oxygen from the system. A variety of
low- or high-pressure purging techniques from volume
displacement to pressure recycling would be utilised.
During this time Air Products’ technicians would monitor
hydrocarbon and/or oxygen levels as required. Following
maintenance work and after leaks have been rectified,
Air Products would re-commission the units as if they were
for a new plant.
On-line leak detection service
The Air Products on-line leak detector uses state of the art quadruple mass spectrometer technology. These types of detectors are widely accepted as the preferred method for many atmospheric pressure gas analysis requirements.
Gas concentrations can be monitored over a wide dynamic range from ppb to percent levels with a speed of up to 150 data points per second.
Mass spectrometers are far more sensitive than other gas detection systems and this method of testing gives consistent results because, unlike passive detectors, the probe does not have to be directly over the leak and does not rely on the operator to ensure the detector passes over all the potential leak areas.
Why APEX Industrial Gas Services?
The APEX team has a unique position in the industry. With over 35 years’ experience in nitrogen-related services, not only can it offer a wide range of nitrogen pressure and temperature supply options, but as part of Air Products it
has a secure and varied supply capability from its industrial gas plants located around Europe.
24 Hour Call-out Service
APEX Industrial Gas Services offers an emergency nitrogen service. Its staff are available on call 24 hours a day and their knowledge and experience in dealing in various chemical and process industry applications enables them to mobilise the right equipment, labour and product supplies at very short notice.
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