Page 33 - 77

According to the European directive of the Trans- DRY
European Transport Network, an average distance GAS
of 400 km should be maintained between refuelling
stations. While this value is widely met in some are-
as, in others like south of Italy or Greece, there is a
lack of refuelling points. Gas Compressor N2 Compressor

LNG for off-grid users
Off-grid users represent those small industries or
other type of consumers for which gas is supplied NGL
by other means than the grid, typically by truck
(LNG). Additional island users are some commu- EFG
nities in the mountains or in other remote locations
where gas is received in liquefi ed form and is then
regassifi ed and injected in a smaller local pipeli-
ne network for domestic and industrial uses. The
trucks bringing LNG to off-grid users may need to LNG
travel a very long distance in those countries where
gas is not distributed in its liquefi ed form as a fuel 1
yet. Distribution costs can be signifi cant and may Liquefl ex ™ process scheme
discourage the use of LNG despite its cleaner envi-
ronmental footprint than the existing alternative so- As the pipeline gas is already treated in complian-
lutions. Therefore, the availability of new distribution ce with market specifi cations, the pre-treatment
points would encourage the development of LNG function of the LNG plant is limited to the further
also among off-grid users. reduction of contaminants to cope with the cryo-
genic liquefaction process (i.e. CO and water re-
2
duction to ppm). The dehydration unit is designed
Saipem solution including two vessels working in parallel mode (one
in adsorption, one in regeneration). The mercury re-
for small scale LNG plants moval beds are installed in series to the molecular
sieves on the same vessels. The dry gas from mo-
The proposed small-scale LNG facilities have been lecular sieve is routed to the liquefaction unit.
designed for 250,000 TPA LNG production, based
on a Saipem proprietary process technology. The The proposed Natural Gas Liquefaction process
relevant patent application has been published for is based on a triple expander refrigeration scheme
this technology and has the following reference: which includes:
• WO/2018/007710 - Method for liquefying na- • two semi-open natural gas turbo-expander Liquefl ex™ module for FLNG
tural gas and for recovering possible liquids cycles that perform NGL extraction and use
from the natural gas, comprising two refrige-
rant cycles semi-open to the natural gas and
a refrigerant cycle closed to the refrigerant gas

The proposed small-scale LNG
facilities have been designed for
“production of 250,000
TPA of LNG, based on a
Saipem’s proprietary process
technology

The LNG facilities installation is designed to liquefy
a pipeline gas with variable heavy hydrocarbon
content, for suppling LNG to cope with small sca-
le applications (e.g. ship bunkering, road fuelling,
etc.).
The LNG plant is envisaged within or in the vicinity
of an existing port, and it is designed considering
the availability of an external power grid.
Different transportation system for export have
also been considered, including trucks, barge and
small-scale LNG tanker.

Impiantistica Italiana - Gennaio-Febbraio 2020 29 29