November
2016
HYDROCARBON
ENGINEERING
100
supply. But there is growing recognition of the superior
safety standards industrial gas companies can offer in
the production of hydrogen too.
Hydrogen production operates at temperatures far in
excess of those that refineries are used to managing.
Industrial gas companies have the necessary expertise to
manage these temperatures to world leading safety
standards.
Of course, safety and environmental regulations vary
from region to region, and many oil and gas businesses
are preferring to outsource this headache – at least from
a hydrogen production perspective – to an industrial gas
expert.
Industrial gas companies are well placed to respond.
In many of Air Products’ SMR plants, for example, low
NO
X
burners and selective catalytic reduction (SCR) units
are deployed to meet strict environmental regulations in
specific regions, with continuous safety training
programmes also enforced.
Pushing innovation
Taking the decision to purchase rather than produce
hydrogen need not mean that refineries miss out on the
cost saving opportunities presented by hydrogen
recovery, however.
Whilst offgases were historically flared or burnt for
energy, there is now a growing move to purify these
gases to recover hydrogen that can be re-used in the
refining process. By recovering hydrogen in this way,
refineries can reduce the amount they need to produce
or purchase, cutting costs.
Far from discouraging this process, savvy hydrogen
producers are in fact encouraging it. Air Products for
example, supports refineries in improving and
optimising their systems, offering hydrogen recovery
using cryogenic or membrane technology. It has
already installed over 90 systems in oil refineries
worldwide, which have the ability to recover 90+% H
2
at 90+% purity.
One such example is the installation of a cryogenic
system in an ExxonMobil US Gulf Coast refinery. Here,
95 million ft
3
/d of a combined hydrocracker offgas and
a catalytic reformer crude hydrogen stream is processed
to produce a purified hydrogen product, a C2+ liquid
product and refinery fuel.
Membrane systems are widely used to treat a
number of refinery offgases such as hydrotreater and
hydrocracker purge streams and catalytic reformer
crude hydrogen.
It is clear, then, that rising hydrogen costs continue
to push innovation amongst suppliers operating both
in the Western and developing world, with refineries
increasingly expecting smart solutions that offer more
than just a hydrogen production facility.
Air Products embraced this challenge as part of the
hydrogen production/cogeneration plant projects,
developed next door to a Valero Energy Corporation
refinery in Port Arthur, Texas. What set this project
apart was its successful integration of combined cycle
technology and SMR technology. Two separate
projects were completed for Valero; the first project
integrated a 37 MW GE Frame 6 gas turbine with a
105 million ft
3
/d steam reformer and the second, larger
integrated facility allowed this plant to simultaneously
produce about 100 MW of electricity, 110 million ft
3
/d
of hydrogen and up to 1.2 million lb/hr of steam.
In this second facility, there are four major operating
units: an SMR hydrogen plant that also produces steam;
a heat recovery steam generator; a 80 MW GE Frame 7
gas turbine generator, the exhaust of which is used as
a combustion air source by both the heat recovery
steam generator and the SMR; and a 20 MW
auto extraction/backpressure steam turbine generator
that produces power and exports steam at two
different pressures.
This combination of technologies results in an
efficient, reliable and safe supply of hydrogen, steam
and power, which, in turn, allows the refinery to convert
more than 300 000 bpd of crude oil into jet fuel, low
sulfur diesel, petrochemical feedstocks, petroleum
coke, and conventional and reformulated gasoline.
These facilities at Port Arthur, and under
construction at the BPCL refinery in India, are the only
SMRs worldwide with an integrated gas turbine
supplying refinery hydrogen, and are a testament to the
value that refineries can gain by engaging an industrial
gas expert.
Conclusion
At the heart of all of these partnerships is a desire for a
long term and reliable hydrogen supply, without which
oil and gas companies cannot operate or turn a profit.
But, in outsourcing their hydrogen requirements,
refineries are increasingly finding opportunities for
efficiency and innovation too, allowing them to
concentrate on, and even enhance, their core business.
As regulations tighten, and margins remain in flux, the
trend to purchase rather than produce hydrogen looks
set to gain ever growing momentum.
Figure 6.
An Air Products hydrogen plant located in
Rotterdam, the Netherlands, supplying ExxonMobil
and other Air Products’ pipeline customers in the
region.
