SGT-300: Providing Fuel
Flexibility & Low Emissions
For Industrial Gas Turbines up to 15 MW
Answers for Energy
CHP users are under increased pressure to optimize the use of their power plant
including, at one extreme, a decision whether to keep their GT power source in
operation, especially with the external influences that affects their businesses.
Amongst these are a number of market drivers that
influence such decisions:
Low Cost Energy from alternative sources, such as
wind and wave power, is increasing
Greenhouse Gas Emissions to atmosphere need to be
reduced to much lower levels
Elimination of airborne ‘pollutants’ to improve air quality
Decreasing dependency on Fossil Fuel paralleled with
the need to reduce pollution
With our past experience of various fuel types and
compositions, Siemens is able to provide a cost-effective
solution, with low emissions and an operational capability
on fuels outside the normal standard fossil fuel range.
In 2006, in response to the demand for energy,
increasing fuel costs and electrical power shortages, the
University of New Hampshire (UNH) took delivery of a
new Siemens SGT-300 gas turbine package, as part of the
Combined Heat & Power (CHP) plant at its Durham Campus.
The CHP plant was required to help provide for the
energy needs of the 13,000 person campus, in an
efficient and cost effective manner. The plant design
centered around one 7.9MW(e) SGT-300 combustion
turbine and heat recovery steam generator with auxiliary
duct firing. The unit was installed with a standard, dualfuel, Dry Low Emissions (DLE) combustion system,
enabling it to meet stringent regulatory limits on exhaust
emissions to atmosphere.
A subsequent phase of the project was to include the use
of renewable, carbon neutral, processed landfill gas (PLG)
as an alternative to liquid fuel and natural gas. This
extension to the turbine application would reduce the
University’s dependence on fossil fuels, proving it to be
both a fiscal and an environmentally responsible initiative.
Landfill gas is a natural by-product from the
decomposition of organic waste, comprised primarily of
methane, a potent greenhouse gas (over 20 times* more
harmful to the atmosphere than carbon dioxide *source:
US Govt. EPA) plus nitrogen and carbon dioxide. It is
further ‘contaminated’ by moisture, Sulphur compounds,
Siloxane, Volatile Organic Compounds (VOCs) and Oxygen.
www.siemens.com/energy
9
Student population over 13,000
108
Landfill
Site
UNH /Siemens SGT-300 reported statistics:
Ambient temperature range: -28°C +32°C
Unit continuous operation 8,500 hrs/yr
16
In commercial operation since 2006
9
>3800 hrs Liquid operation from November 2008 to
March 2009
108
Unit commissioned on PLG, 30 April 2009
>8500 hrs PLG operation to date
Up to 7.8 MW(e) electrical power output
Up to 12MW of heating and cooling
Dover
16
Bellamy
Reservoir
9
Overall CHP efficiency of 77%
<10ppmVd and <25ppmVd at 100% and 59% load,
respectively, for NOx, SOx and CO
Tri-fuel operation: Gas fuel Wobbe index range 32 –
49MJ/m3 (Natural Gas, Processes Land-fill Gas and Liquid)
Tri-generation (heating, cooling, electrical power)
Installation of Active Pilot (Dynamic Fuel Schedule
management software) in October 2009, modified to
support site anomalies. As the PLG, blended with
Natural Gas, varies in composition it can lead to high
‘Band 1’ combustion dynamics and “Flame Out”
Madbury
155
108
UNH runs predominantly at part load, varies load regularly
4
4
Wobbe Index variation and PLG volume, has proven
wider and more frequent than expected
UNH
Durham
4
Fig. 2: The $49m funded University project commenced with the
construction of a gas processing plant at the nearby landfill site in
Rochester. The plant purifies and dries the gas before compressing
it down a purpose built, 12.7 mile long, underground pipeline to
the CHP plant at the Durham campus.
This application provides for the landfill gas to be
captured, converted, blended with Natural Gas and used
as a renewable energy source, instead of allowing it to
escape into the air.
99.02% average availability for the SGT-300 from
November 2009 to March 2010
The SGT-300 gas turbine was designed from the outset to
have low emissions combustion (DLE) as a capability and
is based on the Lincoln generic DLE solution. This DLE
combustion system offers among the widest operability
limits in terms of fuel type, load operation and low
emissions (it has some of the lowest levels recorded across
the SGT product line). The recent addition of ‘Active Pilot’
fuel management software, has allowed for wider
variations in PLG composition to be managed, whilst still
achieving the required emissions to atmosphere.
The landfill gas collection system consists of more than
300 extraction wells and miles of collection pipes. The
extracted landfill gas is compressed and passed to the
processing plant where it is cleaned and enriched (by
removing the Carbon Dioxide) thus making it suitable for
burning in the SGT-300.
The processed landfill gas (PLG) contains Nitrogen as the
dominant inert species, resulting in the gas being some 30
percent weaker than a ‘normal’ pipeline quality natural gas.
UNH are justifiably proud of their investment and as such
invite us to view their plant in operation, go to www.
energy.unh.edu/ to view their website, an extract of
which is shown in Figure 4. It allows the viewer direct
access to ‘live’ data on the performance of the unit,
showing the unit output power, the fuel composition that
it is burning and the level of emissions it is producing.
Gas Fuel
Water
25,140kW
Heat
Recovery
Steam
Generator
Gas Turbine
Exhaust Gas
40,000 to 95,000 lb/hr
at 180 PSI
To Process
Fig. 3: UNH Plant Schematic.
Electrical
Output
7,640kW
Cogeneration Plant - Combustion Turbine Generator Overview
Combustion Inlet Air Cooler
TV-763
-3.3
%Open
1.3 in WC
Gas Selection
Turbine Enclosure Ventilation Air Inlet Filter
0.0 in WC
Temperature Corrected Wobbe Index
Liquid Fuel Filter Differential Pressure
M
CHWS
CHWR
Combustion Air Inlet Filter
Lub Oil Filter Differential Pressure High
0.0 in WC
Generator Air Inlet Filter Differential Pressure
0.0 PSID
Instrument Air Supply Pressure
Inlet Air Temp
56.8 DegF
LCV (Low Calorific Value)
-0.2 PSID
Specific Gravity
Process Landfill Gas
32.3 MJ/Nm3
711.3 BTU/SCF
0.673
104.4 PSIG
Turbine Status
Cooling
Air Inlet
Cooling
Air Outlet
Ventilation
Ventilation
Air Outlet
RUNNING
Air Inlet
CEMS
NOx
13.0 ppm
NOx 15% 13.9 ppm
O2
15.0 %
Governing Operating Mode
KW
Selected Fuel
GAS
Running Fuel
GAS
Fire and Gas System
GENERATOR
TURBINE
Lub Oil Supply Temp.
119.8 DegF
Lub Oil Reservoir Temp.
152.4 DegF
FI-440
Process Landfill Gas
2112.0 SCFM
93.2 Volume % PLG In Blend
6.8 Volume % Natural Gas In Blend
8.9 BTU % Natural Gas In Blend
Avg. Exhaust Temp.
1026.0 DegF
Generator Output Power
Generator Output MVARS
Liquid Fuel Supply Pressure -1.1 PSIG
Generator Output Voltage
Gas Fuel Supply Pressure 303.4 PSIG
Generator Power Demand Signal
0.0 GPM
Fuel Oil Supply
To HRSG-1
MANUAL
7808 kW
2071 MVARs
4253
Volts
8304 kW
Fig. 4: Snapshot of operational mode Tuesday 20th April 2010 at 13:45 GMT, Unit delivering 7.8MW(e) on a 93.2% PLG blend with 6.8%
Natural Gas, at a Wobbe Index of 32.3 MJ/m3 and 13.0 ppm NOx.
Prior to this project, Siemens were already gaining
experience on an earlier SGT-300 project, using depleted
well head gas, containing high levels of Carbon Dioxide.
Additional supporting development testing, using a high
pressure combustion rig, along with ignition demonstration
through an atmospheric facility, enabled the standard
combustor to be released for this application.
Fleet experience continues to grow across a wide range
of applications, many years after this initial work had
been completed. This expanded fuels capability provided
the basis for working with UNH, to define a suitable
operating window, culminating in achieving tri-fuel
operation, i.e. ability to operate with Natural Gas,
Processed Landfill Gas, as well as Distillate Fuel.
In summary, the SGT-300 operating at the UNH campus
runs on three fuels (PLG, NG and distillate) and achieves
NOx guarantee limits throughout the load range, in
standard DLE configuration, without hardware changes
or additional monitoring.
Unit is meeting site energy demands (up to 7.8MW(e)
and 77% overall CHP efficiency)
Unit can tolerate a variable fuel energy content level,
Wobbe Index range 32 – 49 MJ/m3
Unit has maintained emissions level requirements
Acknowledgements:
Extracts from, Brown, J.M., Igoe, B., Bulat, G., Stellmack,
J., 2010 “Industrial Gas Turbines in an evolving and
challenging market: Fuel Flexibility and Emissions
Compliance - The SGT- 300 “.
Our thanks to the University of New Hampshire, for both their
support and for allowing us to mention the developments
that have come to fruition, through their installation.
Total cost of the project, which included construction of the
pipeline and the processing plant at TREE, is $49 million.
UNH will sell the renewable energy certificates (RECs) generated by using landfill gas to help finance the overall cost of
the project and to invest in additional energy efficiency projects on campus. In addition, UNH will sell power in excess of
campus needs back to the electric grid.
“By selling the RECs from EcoLine™, UNH will further fund its
aggressive plan toward climate neutrality,” says Tom Kelly,
UNH chief sustainability officer and director of the office of
sustainability. “With this climate action plan, called WildCAP,
UNH has committed to lowering its emissions by 50 percent
by 2020 and 80 percent by 2080.”
Quotes: DURHAM, N.H. May 19 /PRNewswire/— The University of New Hampshire’s EcoLine™, a landfill gas-to-energy project that uses purified methane gas from a nearby
landfill to power the campus, is complete, university officials
announced. The five million square-foot campus will receive up to 85 percent of its electricity and heat from purified natural gas, making UNH the first university in the nation to use landfill gas as its primary fuel source.
“This massive project, more than four years in the making,
will reduce our dependence on fossil fuels and stabilize our
fuel source and costs,” says UNH President Mark W. Huddleston. “EcoLine™ showcases UNH’s fiscal and environmental responsibility and secures our leadership position in sustainability.”
EcoLine™ is a partnership with Waste Management’s Turnkey Recycling and Environmental Enterprise (TREE) in Rochester, N.H. where the naturally occurring by-product of landfill decomposition is collected via a state-of-the-art
collection system consisting of more than 300 extraction
wells and miles of collection pipes.
The University of New Hampshire, founded in 1866, is a
world-class public research university with the feel of a New
England liberal arts college. A land, sea and space-grant university, UNH is the state’s flagship public institution, enrolling 11,800 undergraduate and 2,400 graduate students.
DURHAM, N.H. – The U.S. Environmental Protection Agency
(EPA) has named the University of New Hampshire’s EcoLine™ as a Project of the Year, the agency announced last
week. EcoLine™ is a landfill gas-to-energy project that uses
purified methane gas from a Waste Management landfill in
Rochester to provide up to 85 percent of campus power.
When EcoLine™ started in May 2009, UNH became the first
university in the nation to use landfill gas as its primary fuel
source.
“We are proud to recognize UNH’s EcoLine, a Landfill Methane Outreach Program partner which is turning trash into a
clean and profitable source of energy,” said Gina McCarthy,
assistant administrator for the EPA’s Office of Air and Radiation. “This project, and others like it, is helping us transition
into a clean energy economy and make important greenhouse gas reductions.”
After the gas is purified and compressed at a new UNH processing plant at TREE, it travels through a 12.7 mile pipeline
from the landfill to UNH’s cogeneration plant, where it will
replace commercial natural gas as the primary fuel source. In
operation since 2006, UNH’s cogeneration plant captures
waste heat normally lost during the production of electricity
and uses this energy to heat campus buildings.
Published by and copyright © 2013:
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