Answers for Energy

SGT-300: Providing FuelFlexibility & Low EmissionsFor Industrial Gas Turbines up to 15 MW

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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, dual-fuel, Dry Low Emissions (DLE) combustion system, enabling it to meet stringent regulatory limits on exhaust emissions to atmosphere.

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.

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.

108

108

9

9

9

108155

Dover

Durham

Bellamy Reservoir

Landfill Site

4

4

4

UNH

16

16

Madbury

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.

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.

UNH /Siemens SGT-300 reported statistics:

Student population over 13,000

Ambient temperature range: -28°C +32°C

Unit continuous operation 8,500 hrs/yr

In commercial operation since 2006

>3800 hrs Liquid operation from November 2008 to March 2009

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

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”

UNH runs predominantly at part load, varies load regularly

Wobbe Index variation and PLG volume, has proven wider and more frequent than expected

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.

Water

Gas Fuel

25,140kW

Electrical Output

7,640kW

Exhaust Gas

40,000 to 95,000 lb/hr at 180 PSI

To Process

Heat Recovery

Steam Generator

Gas Turbine

Fig. 3: UNH Plant Schematic.

CHWS

CHWR

TV-763-3.3

%OpenM

Combustion Inlet Air Cooler

Inlet Air Temp56.8 DegF

Combustion Air Inlet Filter 1.3 in WC

Turbine Enclosure Ventilation Air Inlet Filter 0.0 in WC

Liquid Fuel Filter Differential Pressure -0.2 PSID

Lub Oil Filter Differential Pressure High 0.0 in WC

Generator Air Inlet Filter Differential Pressure 0.0 PSID

Instrument Air Supply Pressure 104.4 PSIG

Gas Selection

Temperature Corrected Wobbe Index 32.3 MJ/Nm3

LCV (Low Calorific Value) 711.3 BTU/SCF

Specific Gravity 0.673

Process Landfill Gas

Cogeneration Plant - Combustion Turbine Generator Overview

Cooling Air Inlet

Cooling Air Outlet

Ventilation Air Outlet Ventilation

Air Inlet

Turbine Status

RUNNING

Governing Operating Mode

KW

Selected Fuel

GAS

Running Fuel

GAS

Fire and Gas System

MANUAL

CEMS

NOx 13.0 ppm

NOx 15% 13.9 ppm

O2 15.0 %

GENERATOR

TURBINEAvg. Exhaust Temp.

1026.0 DegF To HRSG-1

Lub Oil Supply Temp. 119.8 DegF

Lub Oil Reservoir Temp. 152.4 DegF

Liquid Fuel Supply Pressure -1.1 PSIG

Gas Fuel Supply Pressure 303.4 PSIG

Process Landfill Gas

Fuel Oil Supply

Generator Output Power 7808 kW

Generator Output MVARS 2071 MVARs

Generator Output Voltage 4253 Volts

Generator Power Demand Signal 8304 kW

FI-4402112.0 SCFM

93.2 Volume % PLG In Blend 6.8 Volume % Natural Gas In Blend 8.9 BTU % Natural Gas In Blend

0.0 GPM

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

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.

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.

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Subject to change without prior notice. The information in this document contains general descriptions of the technical options available, which may not apply in all cases. The required technical options should therefore be specified in the contract.

Quotes: DURHAM, N.H. May 19 /PRNewswire/— The Uni-versity of New Hampshire’s EcoLine™, a landfill gas-to-ener-gy 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 re-ceive up to 85 percent of its electricity and heat from puri-fied natural gas, making UNH the first university in the na-tion 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. Hud-dleston. “EcoLine™ showcases UNH’s fiscal and environmen-tal responsibility and secures our leadership position in sus-tainability.”

EcoLine™ is a partnership with Waste Management’s Turn-key Recycling and Environmental Enterprise (TREE) in Roch-ester, N.H. where the naturally occurring by-product of land-fill decomposition is collected via a state-of-the-art collection system consisting of more than 300 extraction wells and miles of collection pipes.

After the gas is purified and compressed at a new UNH pro-cessing 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.

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) gener-ated by using landfill gas to help finance the overall cost of the project and to invest in additional energy efficiency proj-ects 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.”

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 uni-versity, UNH is the state’s flagship public institution, enroll-ing 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 Eco-Line™ 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 Meth-ane 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 Radia-tion. “This project, and others like it, is helping us transition into a clean energy economy and make important green-house gas reductions.”