H2Tech - Q1 2022 - 42

INFRASTRUCTURE AND DISTRIBUTION
sion and a cryogenic separation process.
To maintain a comparative basis for
this study, the SMR + CCS route for
pure H2
production followed by N2
jection prior to the NH3
was selected.
Methane
Solar Thermal
Nuclear
Biomass
Coal
Solar PV
OTEC
Wind
Electricity
FIG. 12. Ammonia production processes.1
TABLE 9. NH3 synthesis
Value chain block
NH3 synthesis
NH3 capacity
NH3 capacity
Number of units
Capital Cost
O&M
Power consumption
Total operating cost
Total cost
TABLE 10. NH3 cracking
Value chain block
NH3 cracking
NH3 Capacity
Number of units
Capital cost
O&M
Power consumption
NG requirement
Total operating cost
Total cost
insynthesis
unit
SMR
Haber-Bosch synloop
Converter
Gasification
Heat
Thermochemical
H2
O2
H2 and N2
Electrolysis
ASU
H2
N2
H2 and N2
Electricity
for synloop
Compressor
Cooler
Compressor
Purge
Liquid ammonia
The pure H2
mixing with N2
gas from the SMR after
is fed to a Haber-Bosch
synthesis system. NH3
an exothermic reaction of H2
is produced from
and N2
over
an iron oxide catalyst within this synthesis
loop. After a cooling process, the end
product liquid NH3
is stored and ready to
be loaded onto a ship for transportation.1
The NH3
storage is based on having sufboil-off
gas (BOG) is continuously
returned to the liquefaction
system where it is cooled through a twostage
refrigeration loop.1
NH3
ficient storage to service the number of
ships and their size. The same storage
capacity in Qatar and the UK is assumed
based on refrigerated storage spheres of
50,000 m3
capacity with a margin to allow
for any delay in ship arrival. A boiloff
rate (BOR) of 0.1 vol%/d is assumed
and BOG from storage is re-liquefied and
returned to the tanks at both the loading
terminal and receiving terminal.
NH3
transportation is based on the
use of semi-refrigerated liquefied petroleum
gas (LPG) tankers. The largest
available LPG tanker with a capacity of
85,000 m3
NH3 from Qatar to the UK.2
is considered for shipping
NH3 shipping
infrastructure and storage is a mature
process and in operation worldwide.
At atmospheric pressure, the NH3
than LH2
has
a boiling point of -33°C; therefore, it
is less expensive and more available to
transport NH3
or even LNG-
Capacity
-
1,133,708 metric tpy
3,239 tpd NH3
2
2 x 1,619 tpd
-
50.5 MWe
-
-
Specific value, $/metric t of H2
Qatar
-
-
-
176
211
87
298
473
Notes
[1]
Largest units approx.
2,200 tpd
safety concerns are associated with NH3
leaks, as it is a highly toxic and flammable
chemical that can leak in gaseous
form.3
as a direct fuel.
For the purposes of comparison,
it is assumed that the LPG carriers are
fueled by LNG; however, it can be expected
soon that the ships would operate
on NH3
NH3
(TABLE 10) is the final process to revert
the NH3
8 kWh/kg H2
(depending on the purity of H2
energy intensive, suffers product losses
and can be avoided if NH3
rectly as a fuel. A typical NH3
unit configuration is shown in FIG. 13.
H2
Capacity
1,133,708 metric tpy
1
1 x 1,133,708 metric tpy
-
30.5 MWe
9,700 kWh/metric t H2
-
-
42 Q1 2022 | H2-Tech.com
Specific value, $/metric t of H2
UK
-
-
97
117
97
116
329
427
Notes
[4]
has 85% recovery4
dehydrogenation or cracking
back to H2
was used dicracking
purification
with a PSA at 20 bar
. This results in a H2
loss of about 15% when cracking NH3
back into H2
is an endothermic and ener-some
references have even
lower recoveries. Catalytic dehydrogenation
of NH3
gy-intensive process, with required high
temperatures of 650°C-700°C or greater
over a catalyst. Despite the recent interest
and importance of NH3
dehydrogenation,
limited information exists on the process
development with small capacities.4
The total specific value for the whole
value chain is $2,020/metric t of H2
, split
. This process is costly
required),
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