25 / 60
W
hile the liquefaction of natural gas is not a new
process, its rapid growth in popularity caused
by new abilities to access natural gas resources
has led the industry to look at new technology to make
it both profitable and sustainable. Cooling natural gas
to cryogenic temperatures, and then moving it through
piping systems with little or no leakage, is problematic. It
is taking new technologies to make the process achieve
an acceptable level of leakage, while making the process
safer and more profitable.
Natural gas is often described as the cleanest fossil
fuel. It produces 25 – 30% less carbon dioxide per joule
delivered than oil, and 40 – 45% less than coal. Therefore,
the demand for LNG is steadily increasing, and it will
become of high importance for many countries that want
to add additional sources of supply.
Once processed, natural gas storage and
transportation is carried out in a variety of ways, but the
most unique involve seagoing vessels, tank trucks, storage
tanks and/or pipelines. To save space and costs, the
natural gas can be cooled down to approximately -162°C
(-260°F), turning it into LNG. This liquefaction process has
considerable advantages over traditional transportation
devices because of the condensing of the volume to
approximately 1/600
th
of its original size. Therefore,
significantly more energy can be moved in smaller spaces,
saving money and allowing for greater distances. This
process is one of the faster growing industrial processes
creating a substantial new sector in the energy market
globally. The smaller volume allows for the gas to be
moved more economically when significantly larger loads
can be moved or stored in smaller capacity vessels. In
addition to this, there are regions of the world where the
construction of pipelines is not possible, or the
infrastructure is only rudimentary. Also, in some cases, the
available customer base does not justify the high
construction cost of adding pipelines. In these areas,
natural gas can be supplied in larger quantities using LNG
Scott B. Moreland, QUADAX Valves Inc., USA,
looks
at developments in butterfly valve technology that are
helping the LNG industry to flourish.
23