SEPTEMBER
2014
LNG
INDUSTRY
43
T
he rapid growth in the worldwide LNG industry has led
to a demand for new applications that can track natural
gas and LNG throughout the vessel loading/unloading
process and completely balance the inventory.
Loading or unloading a vessel at an LNG facility is a
multi-step process that involves a liquefaction or regasification
plant, LNG storage tank farm and a natural gas pipeline.
Traditional solutions use separate applications to manage gas
and liquid quantities on the vessel, within the plant, in storage
tanks and through the pipeline. Much of the data input process,
including auditing and balancing, is manual.
A single LNG shipment is a large transaction. A newer model
vessel could have an LNG capacity of 266 000 m
3
or
9.4 million ft
3
. Since the gas/liquid volume ratio is typically
around 609:1, this is equivalent to 161 994 000 m
3
of natural gas.
1
Depending on spot prices throughout the world, at the time of
writing that quantity would be valued between US$ 20 million
and US$ 50 million.
The challenge for an application to track this is multi-faceted
with plenty of issues to complicate matters. The commodity
exists in two states, a cryogenic liquid at a temperature of -162°C
and a gas at nearly room temperature. Throughout the process is
a mix of static tank gauge levels and dynamic flow
measurements. A liquid loading or unloading process produces a
one-time transaction ticket, while gas pipeline flow
measurements are recorded on an hourly basis. Can the quantity
be accurately tracked through such diverse circumstances?
It is important to recognise the demand for accurate LNG
tracking. Until recently, oil and gas companies did not have an
effective method for tracking both gas and liquids. To meet the
demand from such varied operations as LNG facilities, oil and
gas producers and midstream operators, Flow-Cal partnered
with several users to develop an integrated application capable
of managing natural gas, natural gas liquids (NGLs), chemicals,
crude and refined products within a single measurement
application. Now, all measurement information can exist in a
common database.
The FLOWCAL application is able to track natural gas as it
transitions between an LNG vessel and a pipeline. Each step of
the way presents unique issues.
in the balance
George Barnes and Scott Tanner, Flow-Cal Inc., USA,
ask whether measurement applications can meet the
challenge of balancing inventory as it transitions between a
natural gas pipeline and an LNG vessel.
