Venture
Into the World of Industrial Rotating Equipment
Issue 7 | July 2007
Off Limits
70° 39’ North – Sophisticated Wilderness
Focus
ECO-II – The Sweet Sound of Success
Monitor
DLE – Fewer Emissions, Better Economy,
Wider Fuel Range
Lucky draw survey included. Win a Leica camera!
s
Dear Reader,
This issue of Venture combines the heights and depths of technology — major features
cover highly efficient, hi-tech compression solutions for an LNG application with
subsea gas transport and a land-based field compressor with potential for future subsea exploitation. These solutions for the future are already being pioneered in the
present.
From the world’s northernmost LNG plant in Hammerfest, Norway, we go to the
gas fields of the Netherlands, where the newly developed sealless compressor, ECO-II,
is in full production for Shell/NAM. We are particularly proud of the fact that this
design is truly a product of trust and cooperation with our customer, enabling us
to perfect the design to meet current needs, with potential even now for further
development for applications in sensitive environments.
Reduction of emissions, especially CO2, is of increasing concern for our customers.
It is, of course, both an environmental and an economic issue. Siemens’ role here is
clear: to provide the technology efficiency that enables our customers to meet their
environmental commitments. We focus in this issue on the continued development
of DLE (Dry Low Emissions) combustion technology, where demands increase as our
gas turbines operate on an increasing variety of fuels. DLE technology is a standard
feature of our gas turbines, including, naturally, the SGT-400 which has recently
passed the half-million operating hours mark.
Enjoy the read!
Photo: Florian Sander
Dr. Frank Stieler, President
Siemens Power Generation Oil & Gas and Industrial Applications
Inside
Inside
04 News Flash Around the World
14
Projects in Brazil and Belarus.
70° 39’ North — Sophisticated Wilderness
06 Focus ECO-II — The Sweet Sound of Success
The first sealless motor/compressor unit of its kind has just
successfully completed half of a punishing 12-month field trial.
10 Faces Willem Stam, Brian Todd, Etienne Meier
A day out at the ECO-II test site with the joint-development troika from
Shell, NAM, and Siemens.
12 Monitor Fewer Emissions, Better Economy, Wider Fuel Range
The third-generation Dry Low Emissions burner system (DLE) is
already standard with latest Siemens gas turbines.
14 Off Limits
70° 39’ North — Sophisticated Wilderness
A brief visit to Statoil’s Melkøya Island LNG plant near
Hammerfest, Norway.
06
18
18 Spotlight SGT-400 Logs Half a Million Operating Hours
The highest-efficiency gas turbine core in its class, the SGT-400 proves
its wide acceptance in the industry.
19 Dateline Trade Shows, Conferences, Seminars
September to October 2007
IMPRINT
Publisher: Siemens AG, Power Generation Oil & Gas and Industrial Applications, Wolfgang-Reuter-Platz, 47053 Duisburg, Germany Responsible: Dr. Uwe Schütz Editorial Team: Lynne Anderson
(Head), Manfred Wegner Contact: lynne.anderson@siemens.com Contributing Editors: Colin Ashmore Design: Formwechsel Designbüro, Düsseldorf Photography: Florian Sander
Illustration: Ji-Young Ahn Lithography: TiMe Production, Mülheim an der Ruhr Printing: Köller+Nowak GmbH, Düsseldorf
© 2007 Siemens AG. All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical
photocopying, or otherwise, without prior permission in writing from the publisher.
July 2007 Venture 03
News Flash
Belém
Manaus
Natal
Recife
Salvador
Brasília
Belo Horizonte
*1
*1 Petrobras is investing extensively in the oil
and gas exploration and production area in
the Espírito Santo Basin in southeastern
Brazil in order to achieve self-sufficiency by
2009. Siemens delivers a total of seventeen
compressor trains to this mega-project.
Betim
Rio de Janeiro
São Paulo
*2 Combusting residual products from eucalyptus-based pulp production, two SST-800
steam turbine generator sets will cater for
the total energy supply for the new pulp mill
in Três Lagoas, some 600 kilometers from
São Paulo. Surplus electricity will be delivered
to the grid.
Porto Alegre
*3 The SSC-300 is a modularized small CHP
plant, delivering 7.5 megawatt (MW) of
electrical power output and 19 tonnes per
hour of steam.
*2
Photo, Illustrations: *1: Ji-Young Ahn; *2: Siemens AG; *3: Ji-Young Ahn
*3
04 Venture July 2007
News Flash
Around the World
*1 Brazilian Business Booms, …
The oil and gas investment boom in Brazil leads to new Siemens orders
for seventeen compressor trains. Brazilian oil major Petrobras is investing extensively in the oil and gas exploration and production area
in the Espírito Santo Basin in Southeastern Brazil. To process the gas
produced offshore, Petrobras is building a gas treatment plant onshore
at Cacimbas in the state of Espírito Santo. After treatment the gas will
be transported via pipelines linking the Southeast and Northeast Brazilian
regions. The investments will enable Petrobras to increase its local
gas production, enabling Brazil to achieve the goal to be self-sufficient
by 2009.
Siemens is instrumental in both phases of this huge project, supplying
six compressor trains, comprising each one STC-SV compressor driven by
an SGT-200 gas turbine, for the gas treatment plant, and a further
eleven compressor trains with the same configuration which will be
installed in three pipeline stations at Piuma, Aracruz and Prado, along
the coast.
All packaging of components will be done in the Houston facility
in Texas, USA. Spare parts and associated services for erection and
commissioning are included in the deal.
*2 … And Biomass Blooms.
Siemens was recently selected to supply two SST-800 steam turbine
generator sets to a new pulp mill in Três Lagoas, some 600 kilometers
from São Paulo. As the steam for the two turbines will be produced
almost exclusively through the combustion of residual products of the
mill, as much as 90 percent of the total energy production of the site
will be based on biomass. The combined output of the two gensets will
be sufficient to cater for the total energy supply for the factory, and
also enable surplus electricity to be delivered to the grid.
Base material for the pulp production is eucalyptus wood, which has
a short harvesting cycle due to the excellent climate conditions in Brazil.
The first crop will be ready for harvesting when the new factory is
commissioned in 2009. 130,000 acres of fallow meadowland will be
forested with eucalyptus to fuel the mill, but the project will not cause
a single tree to be felled. Original forest lands within the plantation area
will remain intact, providing continued protection for the habitat of
local fauna.
*3 Market Breakthrough for SSC-300 Combined Heat
and Power Plant
Siemens has received its first order for a SSC-300 CHP plant which will
be supplied to Belarus, the crossroads between Eastern and Western
Europe. The customer is PJSC Grodno Azot, the largest chemical manufacturer in Belarus, and one of the largest in Europe. The installation
of the plant will enable the company to be independent of purchased
electricity.
The SSC-300 is a modularized small CHP plant which delivers 7.5
megawatt (MW) of electrical power output and 19 tonnes per hour of
steam. It is characterized by a pre-engineering concept that has introduced a high degree of standardization to the product. In a nutshell,
this pre-engineered, standardized approach leads to higher reliability
and improved plant quality compared with customized solutions.
The supply to Grodno Azot will cover a complete compact power plant
comprising two SGT-300 gas turbines, two heat recovery steam
generators (HRSG), low-voltage system, medium-voltage system and
an automatic control system. The two core modules are the gas
turbine-generator and the HRSGs. Five auxiliary modules, assembled
inside standard containers, house the balance of plant. The containerized modules are specially designed for rapid on-site assembly on
simple foundations which can be prepared before arrival of the components to site. Plant layout can be adapted to fit the space available
on site, with tailored interconnections. The SSC-300 is designed for
outdoor application, thus requiring no building or other expensive civil
works.
Due to its efficiency, the SCC-300 optimizes fuel use and reduces
payback time. The total efficiency rate for the Grodno Azot CHP plant,
including supplementary firing, will be as high as 90.3 percent. Lead
time from order to commissioning of such modularized CHP plants is
in the order of one year. The order from Grodno Azot was received
in March 2007, and commissioning of the plant is thus scheduled for
early 2008.
July 2007 Venture 05
Focus
ECO-II — The Sweet Sound Of Success
Focus
”ECO-II taught us to question a lot of things we
took for granted and forced us to re-invent things.
Once you’re there, you can go anywhere.”
Etienne Meier, ECO-II Project Manager, Siemens
Photos: Florian Sander
Based on truly ground-breaking
technology, a completely new,
electrically-driven gas compressor
named ECO-II has been operating since November 2006 at the
Vries-4 onshore natural gas field
in the Netherlands. With over half
of a punishing 12-month field
trial completed, the prototype
sealless machine has operated
almost faultlessly under ‘real-life’
conditions, boosting gas production by over 20 percent. Remotely
operated and monitored, ECO-II
is also providing vital operating
data to enable further development for future sensitive onshore
and challenging deepwater subsea applications.
Although in the minds of most people the
Dutch are probably associated with windmills,
clogs and tulips, the Netherlands is also the
second largest producer of natural gas in the
North Sea region and the ninth largest in the
world. The discovery in 1959 by NAM (Nederlandse Aardolie Maatschappij BV, a 50-50
partnership between Shell and ExxonMobil) of
the giant onshore Groningen gas field in the
north of the country marked the beginning of a
new chapter in the country's history and the
beginning of the North Sea bonanza. The largest
natural gas reservoir in Europe, covering an
area of some 900 km2, the original NAM discovery proved to contain producible reserves of
around 2,700 billion cubic meters of natural gas.
Although the Netherlands owns substantial
gas reserves in the North Sea, most of its production is currently extracted from onshore
wells, much of it from the huge Groningen reservoir, together with other later discoveries in
the region. Consumption of natural gas in the
Netherlands is only about two-thirds of its
production; the rest is exported, the country
currently ranked the world's fifth-largest
natural gas exporter. With a significant proportion of the gas export revenues claimed by
the state, natural gas from the Netherlands has
provided a major boost to the Dutch economy
and contributed to the country’s continuing
prosperity.
ronmental performance and extend the life of
this major asset by 25 years as a key producer
and as a smaller producer for another 20 years.
In addition to this latest program, the ‘small
fields’ policy, first adopted by the Dutch government in 1974, ensured that a search for other
gas fields was undertaken by NAM to extend the
life of the Groningen reservoir. This exploration program resulted in the discovery and
development of a significant number of
smaller ‘satellite’ reservoirs of natural gas,
which today produce around 12.5 million
cubic meters per year. Together with production
from offshore wells and imported supplies,
these smaller fields now account for two thirds
of current demand, the remainder being supplied by scaled-back production from the main
Groningen reservoir.
Nevertheless, despite the huge volume of
natural gas remaining in the vast underground
reservoirs which lie more than 2.5 kilometers
below the flat and fertile farmlands bordering
the North Sea, continuous production over
more than a quarter of a century has resulted
in a gradual fall-off in gas pressure, as these
vital reserves become increasingly depleted. As
part of the overall long-term field-regeneration
program, NAM and Shell have had to step up
their search for new, economic and environmentally friendly solutions in gas compression
technology, to meet rising energy demand from
mature and fast-depleting reserves.
Life Extension
After some 40 years of continuous production,
around half the available reserves from the
Groningen gas field have been exploited. In
1996, however, NAM launched a 15-year regeneration program designed to improve envi-
Meeting the Challenge
In November 2001 Siemens signed a contract
with joint development partners NAM and
Shell to design, build and deliver a prototype
process-gas compressor which would be
July 2007 Venture 07
Focus
08 Venture July 2007
Focus
compact, capable of operating without emissions, have competitive running costs and
which would require a minimum of maintenance. The solution was both elegant and
groundbreaking in its concept — a compact
centrifugal compressor and electric drive
system housed in a single hermetically sealed
unit. During the next two years a prototype
compressor was designed and built, followed
by a period of extensive factory testing at
Siemens’ facility at Hengelo in the Netherlands.
In developing a fully functional prototype
from the initial concept, the project team had
to meet a continuing series of engineering
and design challenges. These not only included
working with advanced materials and high
technology systems, using many new and unconventional production techniques, but also
overcoming problems with the application of
magnetic bearing technology, including
unknown rotor vibration characteristics and
bearing behavior. With a high-speed, electricmotor-driven machine housed in a compact,
sealed pressure casing, designing a highefficiency cooling system also provided a tough
challenge. The completed prototype machine
was subjected to a variety of tests over many
hundreds of hours at the Hengelo facility,
including performance, endurance and rotor
dynamic testing with many starts and stops.
After successfully undergoing a final continuous
full-speed run for a further 72 hours, the unit
was prepared for shipment for field installation
at the end of April 2006.
Siemens Sealless Solution —
Another World-First
Named ECO II (ECOnomical and ECOlogical),
the prototype compressor is based on the
well-proven design concept used for Siemens’
conventional centrifugal compressors, but
using the very latest materials and technologies.
It employs a high-speed induction motor,
powered through a variable speed drive system
(VSDS). The motor stator is oil-cooled, and the
integrated ‘squirrel-cage’ gas-cooled rotor is
equipped with maintenance-free magnetic
bearings also cooled by gas: a ‘canned’ concept
being employed to isolate the motor stator
from the unprocessed natural gas. However, this
innovative design represents yet another worldfirst for the company as it eliminates completely the need for shaft seals. In conventional gas compression technology, seals are a
vital requirement in order to retain the hightemperature, high-pressure, and potentially
explosive process gas inside the compressor
casing, minimizing leakage along the fastrotating shaft. Even the very latest ‘dry’ gas-seals
require periodic replacement, allow a small
amount of gas to escape and remain the most
sensitive elements in conventional centrifugal
compressors. Without the need for seals, maintenance requirements are slashed and both
productivity and environmental performance
are improved dramatically. In ECO-II the canned
drive motor and compressor are mounted
vertically in a hermetically sealed housing as
a single, integrated unit. This not only simplifies
drainage requirements but requires significantly less space than conventional machines.
It’s a Gas for the Dutch
Installation of the ECO-II prototype commenced
in June 2006 at an unmanned gas processing
facility at NAM’s Vries-4 wellhead site near Assen
in the Groningen region. The facility is located
unobtrusively in the heart of the quiet rural
countryside a few kilometers outside the village
of Vries, its onshore wells tapping into one of
the dozens of satellite gas reservoirs in the area.
After erection and commissioning the machine
was run up to full speed, producing first gas on
November 10, 2006. Since that time ECO-II has
been operating as a conventional depletion gas
compressor as part of Shell and NAM’s commercial activities, ensuring continuation of gas
production from the manifold-connected wells
after their pressure has dropped below freeflow
conditions and boosting production by some
20 percent.
ECO-II — Against All Odds
Far from having a gentle, phased introduction
into the harsh commercial world of natural gas
production, the shiny new prototype machine
has been operating at 45 percent power almost
continuously for more than six months, under
some of the roughest, most arduous conditions
possible. Unmanned, remotely operated,
monitored and controlled, it is not only sited in
the open air without protection from the
elements, but is being used to compress saturated natural gas. Under conditions guaranteed
to give even a conventional machine a tough
time, never mind a high-technology prototype
incorporating advanced technologies being
used for the first time, ECO-II has performed
beyond original expectations. Indeed, with
the exception of an outage caused by a faulty
plug and socket assembly forming part of
the bearing system, the core compressor, whose
performance has been closely and continuously monitored every working second of its
life, has operated perfectly without any significant incident. This level of performance from
the prototype has paved the way to extend the
range of compact, low-maintenance production
machines. It also supports the confidence
that the machines will meet the goal of some
six years of uninterrupted, maintenance-free,
zero-emissions operation.
Waterproof — Futureproof
The 6-MW motor, spinning at a blistering
12,800 revolutions per minute, enables the
compressor to deliver up to 2,795 cubic meters
of gas per hour at a design pressure of 125 bar g.
Reinforcing this positive performance, the
continuous flood of operational and performance data from the ECO-II installation at the
Vries-4 site is providing vital information for
future developments for both land-based and
offshore applications. These not only include
onshore installations for emission-free compression of hazardous and toxic gases in remote
and environmentally sensitive environments,
but will ultimately include the development of
deepwater subsea systems, as existing wells
run dry and oil & gas production moves into
ever more hostile and remote maritime environments. This development will obviate the
need to rely on deepsea platforms.
July 2007 Venture 09
Faces
Triple Jump
The development of ECO-II tells a story of just what
client-supplier relationship can mean. On a sunny
spring day out at the Vries-4 site near Groningen,
Netherlands, Venture met with Willem Stam,
Team Leader Mechanical Equipment, EPE Europe,
with Shell U.K. Ltd. in Aberdeen, United Kingdom;
Brian Todd, Project Engineer with NAM in Assen,
Netherlands; and Etienne Meier, Project Manager
with Siemens Industrial Turbomachinery B.V. in
Hengelo, Netherlands.
Venture: Gentlemen: Shell, NAM and Siemens have been cooperation partners
for quite some time. Any current hot projects to interest our readers?
Meier: Well, one of our larger ongoing projects is the beefing up of
compressor power at 29 clusters of the Groningen Long Term (GLT)
project with compressor trains featuring VSDS drives and automatic
magnetic bearings. And recently, we have delivered a gas-turbine driven
compressor unit for Shell UK for the offshore facility Sean in the North
Sea for which the commissioning is started. Just two of a number of
exciting projects together with Shell and/or NAM.
Todd: Don’t forget the offshore contracts! Since about 2001, every
centrifugal compressor for NAM offshore platforms has come from
Siemens, including K15, L9 and a number of others.
Stam: Over the last few years we have signed global frame agreements
on new and brown-field modifications and also maintenance support
contracts.
Venture: ECO-II, however, is a different story. It’s about joint development
of a whole new approach. It’s a fair guess Shell and Siemens wouldn’t have
teamed up if there had not been a special relationship before?
Stam: That’s right. This machine is a quantum leap in compressor
technology from the word Go, not the result of incremental improvements.
It wouldn’t have been possible without our long-standing iterative
relationship. Typical of that is that the Shell research team has been part
10 Venture July 2007
Faces
of the joint development group — fairly unique in a customer-supplier
relationship.
Todd: It has to be said, though, that Siemens’ ECO-II is still the one and
only such machine that’s capable of running in saturated natural gas,
not just pipeline-quality dry gas. At this site, the ECO-II sees all kinds of
contaminants, including sand, and water in general use-and-abuse
operation.
Venture: Feasibility study in 1999; pilot order in 2001; workshop test from
end of 2004 to end of 2006; start of field test in November 2006; end of field
test in December 2007: What’s next on the agenda?
Meier: After evaluation of the performance, including visual inspection
of all developed parts and materials, we expect to release the ECO-II
compressor concept by end of 2007. Formally, this is the end of the first
stage of the ECO-II development.
Venture: And with regard to future applications of the ECO-II concept?
Stam: The future of the machine within our organization clearly lies
within Shell rather than NAM. The fact that ECO-II is hermetically
sealed against fugitive emissions, together with its 6-year maintenance
interval, means it’s a technically, environmentally and commercially
viable solution for a number of niche applications involving sour or toxic
gas, as well as subsea production.
Todd: For the NAM organization, this machine will be a one-off; centrifugal compression is fairly minimal due to the limited size of our fields.
Venture: What will become of this ECO-II prototype, once field testing has
been completed?
Todd: It will carry on as a standard operational machine, which, I think,
says a lot about the machine. In fact, I guess the biggest compliment
you can give the machine — and Siemens — is the fact that everyone
within the NAM operations already considers it an extension of the
producing facilities rather than a prototype.
Venture: A last word on ECO-II?
Stam: The concept is the perfect answer to a number of imminent
requirements in the oil & gas industry. And, as this site proves, it’s working
and living up to or even exceeding expectations. I’m sure ECO-II has a
bright and lasting future in many areas of our business.
Meier: ECO-II taught us to question a lot of things we took for granted,
and forced us to re-invent things. Once you’re there, you can go anywhere.
Todd: Indeed, our good old friend Murphy was around in every corner.
He made the project very challenging for each of the three parties. But
with a phenomenal result.
July 2007 Venture 11
Monitor
Fewer Emissions, Better Economy,
Wider Fuel Range
Illustration: Ji-Young Ahn
In 1991, a unique Dry Low Emission (DLE) combustion system
was introduced into Siemens’ SGT-600 25-megawatt (MW)
gas turbine. With an accumulated operating experience of
more than 2.5 million hours, this DLE system has now
become the standard configuration for an SGT-600. Progress,
however, continues, as the persistent quest for reduction
of greenhouse gases and improvement of fuel economy is at
the center of attention.
12 Venture July 2007
Monitor
From Heron’s ‘Aeolipile’ through da Vinci’s
‘Chimney Jack’ to Franz Stolze’s design of the
first true gas turbine engine, gas turbine technology — in the widest sense — took some
2,000 years from principle to first engine. It took
another 100+ years to improve its efficiency
from the mere 4 percent of Stolze’s machine to
the near 40 percent of today’s machines.
In recent years, much effort — and money —
has been invested to optimize SGT-600 components such as the combustor, the performance
of which directly impacts on efficiency and,
hence, emissions and economy. The SGT-600
DLE combustor technology itself is simple,
reliable, and low in cost: there are no moving
parts and only two control valves for pilot gas
and main gas. Development has been rapid.
When the first generation DLE-burner was
introduced in 1986, it achieved a NOx level of
75 parts per million (volume) (ppmv, dry).
Experience from this model was incorporated
into a later version, which entered the market
only five years later. The technology uses lean,
pre-mixed fuel in a two-slotted cone/burner,
with a guaranteed NOx level of 25 ppmv (dry).
Pilot gas and main gas are supplied through
fuel rods to the 18 burners in the annular combustor chamber, as is the oil for dual-fuel
engines.
Fighting CO
Extremely low NOx emissions of the SGT-600
over the whole operating envelope has been
a challenge clearly mastered by DLE technology.
To achieve lower CO emissions at part load at
the same time, a combustor bypass system has
been developed. The bypass system is integrated
into the turbine casing. The system consists of
six valves controlled by one actuator. Opening
of the bypass valves means that the airflow to
the burners decreases, the flame temperature
increases and CO emissions decrease. The bypass system keeps the flame temperature and
the emission levels constant at 70 to 100 percent
load. Hence, pilot fuel ratio and bypass
opening are the two parameters that maintain
combustion stability whilst keeping emissions
low across the load range.
methane and nitrogen, is used as fuel for the
gas turbine. With modifications to the pilot
fuel ratio control, even this gas can be handled
with the current standard DLE design.
To handle even lower heating value, however,
the main and pilot gas holes have to be
increased. Design rules for this scaling have
been established. Since the technology is
simple, a further stretching of the limits in
terms of heating value is seen as a low risk.
Continuous Improvement
Refining the system yet further
Over the past years, the system has been
continually improved. A new emission control
system has been introduced, which is less
sensitive to ambient operating conditions
including seasonal swings in temperature. In
the new SGT-600 turbines, this system is fitted
as standard. For the rest of the fleet, it is
offered as a retrofit option. The system is based
on the flame temperature, which reflects the
thermal load on the combustor and compensates
for ambient temperature, relative humidity
and cleanness of the compressor.
Further development has been carried out
on the lean-mixture principle. A four-slot cone
and an added mixing tube reduces NOx emissions further down to 15 ppmv, (dry). This type
of burner is already standard in the more
recently commercialized turbines, the 29-MW
SGT-700 (30 units sold) and 45-MW SGT-800
(50 units sold). One installation exists for the
SGT-600. Siemens’ most recent gas turbine,
the SGT-700, is based on the well proven SGT600 with some innovative design elements
from the larger SGT-800, including the combustion system. The SGT-800 gas turbine is a
single-shaft machine designed for the power
generation and cogeneration markets, while
the SGT-600 and SGT-700 are equally versatile
for power generation or mechanical drive.
Their reliability is making them increasingly
popular for applications in the oil and gas
industries.
Such is the proven success of the DLE systems
that the original, conventional combustion
system is now available only as an option for
customers whose turbines run primarily on
liquid fuel. A DLE system is now standard in all
new industrial gas turbine deliveries.
Extending the Fuel Range
The majority of the SGT-600 DLE engines operate on normal natural gas. However, a number of
units in the Netherlands operate successfully
on Groningen gas, which has 80 percent of the
heating value of normal natural gas (defined
as having a lower heating value (LHV) of 46.8
MJ/kg).
Moreover, in a privately owned LNG plant in
Western China, one machine is running on a gas
with only 60 percent of the heating value of
normal natural gas. The boil-off gas from the
LNG refrigeration process, consisting of
July 2007 Venture 13
Off Limits
70° 39’ North — Sophisticated Wilderness
End of this year, Statoil’s Melkøya Island LNG plant near Hammerfest, Norway, will start
operation. It will be the world’s northernmost LNG facility, and the first ever all-electric
natural gas liquefaction plant. Four massive 65-megawatt (MW) Siemens variable
speed drive systems (VSDS) work at the heart of the plant, together with a range of
compressors for CO2 re-injection, methane mix and other applications.
14 Venture July 2007
Off Limits
Allegedly the world’s northernmost town,
Hammerfest has always been a point of interest
for European tourists roaming the Scandinavian fjells and fjords. Once having crossed the
Polar Circle, visiting Hammerfest has been
and still is a must for many.
The town’s traditional economic basis has been
fish, not tourism. And, at times when there
was still enough fish in the seas off Northern
Norway, Hammerfestians were quite picky
about what they had in their nets. Mackerel,
a delicacy elsewhere, they considered ‘yfisk’, or
‘unfish’, merely good enough for bait.
Today, however, the fruits of the sea would
hardly provide a sustainable economic basis.
Instead, while marvelling at the eternal beauty of the Bay with its glorious sunsets over melting winter snows, the visitor will notice that
Hammerfest has become something of a boomtown. Here the excitement is gas — natural gas.
Hammerfest has become the site of one of the
most highly profiled infrastructure projects
in recent times, as the mysterious ways of gods
and men are beginning to resolve themselves
recognizably into the world’s most northerly
LNG plant, which is due to come on line in
December this year.
In Search of Snow White
It was between 1981 and 1984 when Statoil, the
state-owned Norwegian oil and gas company,
prospected three huge gas fields in the Barents
Sea some 140 km off the North Norwegian
coast. Baptized Snøhvit, Albatross and Askeladd,
they were estimated at a cumulated volume
of 317 billion standard cubic meters. While this
was positive news, the remoteness of the fields
required a fresh approach for bringing the gas
to consumers. Adopting new technology has
allowed Statoil to achieve what few people had
thought possible — the first offshore development in the Barents Sea. Without surface
installations, this Snøhvit project involves
bringing huge volumes of natural gas to land
for liquefaction and export from the first
plant of its kind in Europe.
July 2007 Venture 15
Photos: Florian Sander, Illustration: Ji-Young Ahn
Total capital investment of Snøhvit, as the overall project is labelled, will be in excess of 59 billion Kroner, equivalent to some 9.7 billion USD,
including the development of the three fields,
the subsea wellhead installations, the subsea
pipeline to Hammerfest and the land plant.
The latter is the most prestigious part of the
project; it made Hammerfest a point of interest
for the global oil and gas industry.
Barge Plant
Due to the geographical conditions in northern
Norway, the majority of the gas liquefaction
unit, with the refrigerant compression trains at
its core, could not be assembled onsite. This
led to the development of the barge concept by
the Snøhvit project lead Statoil ASA, in which
components were assembled on the barge, fitted
in place, and the entire barge being subsequently shipped to Norway on a heavy lift ship.
Upon arrival at Melkøya Island on July 13, 2005,
the barge was floated into land and the components were integrated into the site, a specially
preconstructed dock which had been prepared
to receive them. The raft, complete with components, was cemented into place to become
16 Venture July 2007
an integral part of the site. This neat and speedy
arrangement is considerably more economical
than building on land, and greatly reduces the
need for steelwork. Two air compressors were
shipped out separately and transported directly
to Melkøya Island, as their function in the air
separation unit is independent of the ‘barge
plant’.
Going ‘Hot’
Although the extreme weather conditions in
northern Norway meant that the barge was
assembled in Cadiz with its more moderate
climate, the environmental conditions in
southern Spain actually added to the challenges
involved in the project. During the many
months of installation work on the compressor
packages, with the weather changing from
frosty to tropical, and the works premises changing from dusty to muddy and vice versa, the
challenge was to coordinate the work with many
other vendors, disciplines and trades, whilst
hundreds of workers swarmed in and out of the
many decks and compartments on the barge.
At the other extreme, installation of the air
compressors at Melkøya was accompanied
by heavy snow and frost, and the wind chill of
wintertime.
As a result, four years of detailed and laborious
preparations are about to reach their climax,
and the formerly deserted island of Melkøya
will never be quite the same again. Armies of
precision-drilled engineers are making their
final tests and measurements, and engineered supplies from all over the world are
being linked, trimmed and primed for action.
In December 2006, Statoil received approval
from the Petroleum Safety Authority of Norway
(PSA) to start operation of the Hammerfest LNG
plant on Melkøya island. Authorization to
receive the first wellstream from the field and
to start normal production at Melkøya were
also included.
Considering the total scale of the Snøhvit
megaproject, Siemens role is quite humble, but
nonetheless exhilarating, and challenging
in terms of technology, management and coordination. In addition to the massive 65-MW
VSDS electric motors driving the plant’s refrigerant compressors, Siemens supplied six
compressors used at various stages of the gas
liquefaction process and for CO2 re-injection.
The first offshore development in the Barents Sea:
The Snøhvit, Albatross and Askeladd fields,
some 140 kilometers off the North Norwegian coast.
Two of them together were the largest ever
to leave the factory in Duisburg, Germany, when
they were shipped in 2004. This was before
Siemens invested in a new testbed for megascale
compressors and drives which are currently
in demand for the gas liquefaction industry.
The Siemens units were manufactured for
the specific conditions prevailing in the Arctic
region and are designed for ambient temperatures down to -22°C. Special technical features
include glass reinforced plastic (GRP) water
lines, the use of many high-quality stainless
steel materials, winterization with heat tracing
and weather protection, and demanding,
accurately separated coating systems such as
thermally sprayed aluminum. All compressors,
apart from the air compressors, are equipped
with dry gas seals, which require sophisticated,
highly complicated seal gas systems with a lot
of piping to and from the compressor.
Re-injecting CO2
The compressors will be used at various stages
in the gas liquefaction process, including CO2
re-injection. In addition to the six production
wells, drilling at the Snøhvit field included
one well for the re-injection of carbon dioxide —
one of the main components of natural gas.
Gas from the Snøhvit area contains five to
eight percent CO2, which will be separated out
at the land plant.
The CO2 will be compressed from 1 to 61 bar by
the 24-XT-101 compressor, the largest of the
turbo-compressors, with a capacity of approximately 100 tonnes of CO2 per hour, at a rating
of 10 MW. As it is then cooled to approximately
15°C, the CO2 condenses to liquid, which is
then pumped back in a separate line for underground storage beneath the seabed at the
Snøhvit field. This has the advantage of saving
CO2 emissions tax, an important consideration
in Norway.
The remaining Siemens compressors are used
to process the various natural gas fractions.
Four compressors are part of the ‘barge plant’,
the core of the liquefaction process. The 60XT-101 compressors will be used to supply air
to the air separation unit that is a vital utility
for the liquefaction plant. Nitrogen (N2) is provided to the plant once it has been separated
from the air.
Paving Future Avenues
Snøhvit is the first offshore project in the
Barents Sea and will be the first LNG producer
in Europe. Meticulous environmental standards have been incorporated into the development solution, which is highly researched,
and the largest industrial development in the
history of northern Norway. Statoil also aims
to find new gas resources in the Barents Sea in
order to increase the capacity of the onshore
Hammerfest LNG plant. Parts of the Snøhvit gas
will be exported to the USA, and U.S. authorities have approved a twofold increase in the
receiving capacity at Cove Point, Maryland,
LNG import terminal.
Statoil believes that LNG will become a considerable element in the group’s marketing
strategy. The global gas market is growing, and
thanks to LNG technology the markets can be
supplied with gas that will not be available as
pipeline gas. The Snøhvit development is a
first step for Statoil in the development of the
gas resources in the far north. While carrying
the name of a fairy tale character, Snøhvit has
already become a fascinating part of reality.
July 2007 Venture 17
Spotlight
SGT-400 Logs Half a
Million Operating Hours
In the ten years since its market introduction, the SGT-400 industrial gas
turbine has clocked up the major milestone of 500,000 hours of commercial
operation, confirming the turbine to be a well proven machine with wide
acceptance by the industry. Fleet leaders have logged more than 54,000 hours,
which is the equivalent of more than six years of continuous operation.
What’s more, the SGT-400 is the highest-efficiency gas turbine core in its
class with 36.2 percent efficiency at shaft output, minimizing greenhouse
gas emissions. Utilization of the exhaust heat in cogeneration applications has demonstrated total energy efficiency levels of 87 percent. Dry
Low Emissions (DLE) technology is fitted as a standard option, controlling NOx emissions on gas and liquid fuels. As evidence of the acceptance
by the industry of the SGT-400 as a proven machine, Siemens has
achieved type approval from third-party certifying bodies such as Lloyds.
The product has also been approved by major oil and gas companies
for power generation and mechanical drive.
Community Benefits from Revamped Power Plant
Recent sales have included supply of two SGT-400 gas turbines to the
Co-op City power plant located in the Bronx, New York. Also included in
18 Venture July 2007
the order were a SST-300 steam
turbine and the balance-of-plant
distributed control system. With an
installed capacity of 40 MW, this power
generating facility will provide enough
base-load capacity (24 MW) to meet the electricity needs of Co-op City’s 60,000 residents.
Additional power (16 MW) will be sold back into the
power grid to generate revenues that will fund capital
improvement projects. The power plant is expected to be commissioned
in fall 2007.
Co-op City is the largest cooperative housing development in the United
States, and one of the largest in the world. Located in the Bronx in
northeast New York City, it consists of nearly 16,000 residential units with
over 60,000 residents. The existing complex was built in 1971 by an
organization that is now known as Riverbay. In 2000, Riverbay began
large-scale renovations, including replacing piping, rehabilitating
parking garages, repairing facades and installing new windows and elevators. And repowering their power plant.
The repowering of the existing plant will allow Riverbay to produce
power for its residents at a lower cost and sell surplus power to the surrounding areas. Funds generated from the sale of power will assist with
the repayment of capital project loans for renovations.
See the Siemens megacity microsite to find out more about what Siemens
is doing in one of the largest, most thriving cities in the world:
www.siemens.com/newyork
Illustration: Ji-Young Ahn
With a terminal power rating of
12.9 MWe for electrical generation,
and a shaft output power of 13.4 MW
for mechanical drive, the two-shaft SGT400 is a compact and reliable prime mover
for a broad spectrum of applications. Over one
hundred SGT-400 units have been sold to eighteen
countries in four continents, where the turbine is
proving its flexibility: providing power for pipeline compressor
stations in Alaska; generating power and heat to the community in
Germany; working offshore in oil and gas pumping applications in West
Africa; and giving secure and efficient power and heat to ceramics
industries in South East Asia. All units are supported by Siemens global
field service network.
Dateline
Dateline
04–07 September 2007
09–12 October 2007
OFFSHORE EUROPE, Aberdeen, UK
Aqua Ukraine, Kiev, Ukraine
http://www.offshore-europe.co.uk
http://www.tech-expo.com.ua/eng/aqua/home.php
04–06 September 2007
POWER GEN ASIA, Bangkok, Thailand
http://pga07.events.pennnet.com
04–06 September 2007
VGB Combined Heat and Power Congress,
Wuerzburg, Germany
http://www.vgb.org/IHKW_2006_e.html
02–05 October 2007
KIOGE 2007, Almaty, Kazakhstan
http://www.kioge.com
15–17 October 2007
Weftec, (Water Technologies Federation),
San Diego, USA
http://www.weftec.org/home.htm
15–18 October 2007
PCV Expo (Pumps, Compressors, Valves),
Moscow, Russia
http://www.pcvexpo.ru/defaulteng.stm
23–24 October 2007
BMWi Symposium Chemicals & Petrochemicals, Abu Dhabi, Dubai
24–26 October 2007
10th EEPC Olefin Conference, Rome, Italy
www.siemens.com