TK Stainless

high-performance materials
speCiaL FreiGhTers transport the liquefied
natural gas across the oceans. the plant and pipes for
lng technology require titanium and nickel alloys.
---
the liquefied gas into tankers with capacities of up to 140,000
cubic meters, which ship it to the importing countries. Plate heat
exchangers are used to cool the oil of the ships’ diesel engines
during transportation. “20 tons of titanium per ship are used for
this,” explains Helmut Jost, head of marketing at ThyssenKrupp
Titanium in Essen. “Titanium’s special resistance to seawater
corrosion makes it the only material suitable for use in these
coolers.” At the port of destination the LNG is unloaded in special
terminals, after which the liquid gas is regasified and fed into the
supply grid. “The draft of the big tankers makes it impossible for
them to move right up to the shore,” explains Dr. de Boer, head
of applications technology at ThyssenKrupp VDM in Werdohl.
“So pipelines several kilometers long extend out to sea from
the land.” Unlike conventional pipes, which rest on supports
above sea level, new developments make it possible to lay the
pipes either below or on the sea bed. Compared with the raised
structures, these pipelines are more environment-friendly, lower
in cost and offer greater safety.
The pipelines comprises a combination of various
materials in several “layers”: The outer pipe is a concrete-clad
steel pipe, while the inner pipe is made from the VDM material
Pernifer 36. Depending on the pipe diameter, ThyssenKrupp VDM
supplies up to 200 tons of plate for one kilometer of pipeline,
and some export terminals require pipeline lengths of over 15
MaGaZine
kilometers. Various stainless steel processors then produce
longitudinal-welded pipes from the material in diameters of 24
to 36 inches. “The material is ideal for this application,” says Dr.
de Boer. “Its combination of extremely high cryogenic toughness
and very low coefficient of thermal expansion ensure that long
pipelines can be laid without the need for bends or expansion
bellows.” The latter would normally be necessary because the
temperature of the outer pipe is always close to the ambient
temperature, while that of the inner pipe varies between ambient
temperature and minus 165 degrees Celsius. To avoid heat losses,
there is an additional insulating layer between the two pipes.
ThyssenKrupp VDM has also addressed the specific requirements
of these applications and has developed special production routes
and a welding filler metal which allow the production of extremely
long pipe segments. This meets the high safety requirements of
the terminal operators and reduces production costs.
Experts predict that LNG’s share of the global gas
industry will rise significantly over the next 25 years. “There are
currently 146 tankers under construction,” says Jost. “Demand
for corresponding terminals and gas liquefaction plants is also
growing continuously. This is a future market for our material and
our company.” Dr. de Boer is also optimistic: “We expect a steady
increase in customer orders and are pleased to be making a contribution
to the development of alternative energy sources.“ ---
97