Effect of Change in Fuel Compositions and Heating Value on Ignition and Performance for Siemens SGT-400 Dry Low Emission Combustion System

2013 ◽  
Author(s):  
Kexin Liu ◽  
Pete Martin ◽  
Victoria Sanderson ◽  
Phill Hubbard
Keyword(s):  
Natural Gas ◽  
Fuel Composition ◽  
Test Results ◽  
Combustion System ◽  
Combustion Dynamics ◽  
Heating Value ◽  
Fuel Flexibility ◽  
Low Emission ◽  
Burner Design ◽  
Industrial Gas Turbine

The influence of changes in fuel composition and heating value on the performance of an industrial gas turbine combustor was investigated. The combustor tested was a single cannular combustor for Siemens SGT-400 13.4 MW dry low emission (DLE) engine. Ignition, engine starting, emissions, combustion dynamics and flash back through burner metal temperature monitoring were among the parameters investigated to evaluate the impact of fuel flexibility on combustor performance. Lean ignition and extinction limits were measured for three fuels with different heat values in term of Wobbe Index (WI): 25, 28.9 and 45 MJ/Sm3 (natural gas). The test results show that the air fuel ratio (AFR) at lean ignition/extinction limits decreases and the margin between the two limits tends to be smaller as fuel heat value decreases. Engine start tests were also performed with a lower heating value fuel and results were found to be comparable to those for engine starting with natural gas. The combustor was further tested in a high pressure air facility at real engine operating conditions with different fuels covering WIs from 17.5 to 70 MJ/Sm3. The variation in fuel composition and heating value was achieved in a gas mixing plant by blending natural gas with CO2, CO, N2 and H2 (for the fuel with WI lower than natural gas) and C3H8 (for the fuel with WI higher than natural gas). Test results show that a benefit in NOx reduction can be seen for the lower WI fuels without H2 presence in the fuel and there are no adverse impacts on combustor performance except for the requirement of higher fuel supply pressure, however, this can be easily resolved by minor modification through the fuel injection design. Test results for the H2 enriched and higher WI fuels show that NOx, combustion dynamics and flash back have been adversely affected and major change in burner design is required. For the H2 enriched fuel, the effect of CO and H2 on combustor performance was also investigated for the fuels having a fixed WI of 29 MJ/Sm3. It is found that H2 dominates the adverse impact on combustor performance. The chemical kinetic study shows that H2 has significant effect on flame speed change and CO has significant effect on flame temperature change. Although the tests were performed on the Siemens SGT-400 combustion system, the results provide general guidance for the challenge of industrial gas turbine burner design for fuel flexibility.

Effect of Change in Fuel Compositions and Heating Value on Ignition and Performance for Siemens SGT-400 Dry Low Emission Combustion System

2013 ◽  
Vol 136 (3) ◽  
Author(s):  
Kexin Liu ◽  
Pete Martin ◽  
Victoria Sanderson ◽  
Phill Hubbard
Keyword(s):  
Natural Gas ◽  
Fuel Composition ◽  
Test Results ◽  
Combustion System ◽  
Combustion Dynamics ◽  
Heating Value ◽  
Fuel Flexibility ◽  
Low Emission ◽  
Burner Design ◽  
Industrial Gas Turbine

The influence of changes in fuel composition and heating value on the performance of an industrial gas turbine combustor was investigated. The combustor tested was a single cannular combustor for Siemens SGT-400 13.4 MW dry low emission engine. Ignition, engine starting, emissions, combustion dynamics, and flash back through burner metal temperature monitoring were among the parameters investigated to evaluate the impact of fuel flexibility on combustor performance. Lean ignition and extinction limits were measured for three fuels with different heat values in term of Wobbe Index (WI): 25, 28.9, and 45 MJ/Sm3 (natural gas). The test results show that the air fuel ratio at lean ignition/extinction limits decreases and the margin between the two limits tends to be smaller as fuel heat value decreases. Engine start tests were also performed with a lower heating value fuel and results were found to be comparable to those for engine starting with natural gas. The combustor was further tested in a high pressure air facility at real engine operating conditions with different fuels covering WIs from 17.5 to 70 MJ/Sm3. The variation in fuel composition and heating value was achieved in a gas mixing plant by blending natural gas with CO2, CO, N2, and H2 (for the fuel with WI lower than natural gas) and C3H8 (for the fuel with WI higher than natural gas). Test results show that a benefit in NOx reduction can be seen for the lower WI fuels without H2 presence in the fuel and there are no adverse impacts on combustor performance except for the requirement of higher fuel supply pressure, however, this can be easily resolved by minor modification through the fuel injection design. Test results for the H2 enriched and higher WI fuels show that NOx, combustion dynamics and flash back have been adversely affected and major change in burner design is required. For the H2 enriched fuel, the effect of CO and H2 on combustor performance was also investigated for the fuels having a fixed WI of 29 MJ/Sm3. It is found that H2 dominates the adverse impact on combustor performance. The chemical kinetic study shows that H2 has significant effect on flame speed change and CO has significant effect on flame temperature change. Although the tests were performed on the Siemens SGT-400 combustion system, the results provide general guidance for the challenge of industrial gas turbine burner design for fuel flexibility.

Reduction of Burner Variants for Differing Fuel Compositions by Combining Intelligent Control Methods and Experimental Data of Siemens SGT-400 Dry Low Emission Combustion System

2018 ◽  
Author(s):  
Phill Hubbard ◽  
Kexin Liu ◽  
Suresh Sadasivuni ◽  
Ghenadie Bulat
Keyword(s):  
Natural Gas ◽  
Combustion System ◽  
Fuel Flexibility ◽  
Low Emission ◽  
Current Production ◽  
Gas Fuel ◽  
Temperature Controlled ◽  
Wobbe Index ◽  
Industrial Gas Turbine ◽  
Standard Production

Extension of gas fuel flexibility of a current production standard SGT-400 industrial gas turbine combustor is reported in this paper. A successful development program has increased the capability of the standard production dry low emissions burner configuration to burn a range of fuels covering a temperature corrected wobbe index from 30 to 49 MJ/m3. A standard SGT-400 13.4 MW dry low emission double skinned combustor can was tested with a standard production gas burner for a cannular combustion system. Emissions, combustion dynamics, fuel pressure and flashback monitoring via measurement of burner metal temperatures, were the main parameters used to evaluate the impact of fuel flexibility on combustor performance. High pressure rig tests were carried out to demonstrate the capabilities of the combustion system at engine operating conditions across a wide range of ambient conditions. Variations of the fuel heating value were achieved by blending natural gas with CO2 as diluent. The standard SGT-400 combustion system employs proven dry low emissions technology for natural gas and liquid fuels such as diesel within a specified range of fuel heating values. With the aid of novel intelligent control software, the gas fuel capability of the SGT-400 standard dry low emissions burner has been extended, with the engine, achieving stable operation and reduced emissions across the load range despite variations of the composition of the fuel supply. This, combined with previous experience from high pressure rig and engine testing of the different burner configurations that covered this range, resulted in a reduction in the number of hardware configurations from three burners to two. Testing showed that the standard production burner can reliably operate with a fuel temperature controlled wobbe index as low as 30 MJ/m3 which corresponds to 20% CO2 (by volume) in the fuel. The performance of four different fuels with heating values in terms of temperature controlled wobbe index: 30, 33, 35 and 45 MJ/m3 (natural gas), is presented for the current production hardware. Test results show that NOx emissions decrease as the fuel heating value is reduced. Also note that a decreasing temperature controlled wobbe index leads to a requirement to increase the fuel supply pressure. The tests results obtained on the Siemens SGT-400 combustion system provide significant improvement for industrial gas turbine burner design for fuel flexibility.

Extension of Fuel Flexibility by Combining Intelligent Control Methods for Siemens SGT-400 Dry Low Emission Combustion System

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Kexin Liu ◽  
Phill Hubbard ◽  
Suresh Sadasivuni ◽  
Ghenadie Bulat
Keyword(s):  
Gas Turbine ◽  
Operating Conditions ◽  
Combustion System ◽  
Combustion Dynamics ◽  
Heating Value ◽  
Fuel Flexibility ◽  
Wide Range ◽  
Wobbe Index ◽  
Industrial Gas Turbine ◽  
The Impact

Extension of gas fuel flexibility of a current production SGT-400 industrial gas turbine combustor system is reported in this paper. A SGT-400 engine with hybrid combustion system configuration to meet a customer's specific requirements was string tested. This engine was tested with the gas turbine package driver unit and the gas compressor-driven unit to operate on and switch between three different fuels with temperature-corrected Wobbe index (TCWI) varying between 45 MJ/m3, 38 MJ/m3, and 30 MJ/m3. The alteration of fuel heating value was achieved by injection or withdrawal of N2 into or from the fuel system. The results show that the engine can maintain stable operation on and switching between these three different fuels with fast changeover rate of the heating value greater than 10% per minute without shutdown or change in load condition. High-pressure rig tests were carried out to demonstrate the capabilities of the combustion system at engine operating conditions across a wide range of ambient conditions. Variations of the fuel heating value, with Wobbe index (WI) of 30 MJ/Sm3, 33 MJ/Sm3, 35 MJ/Sm3, and 45 MJ/Sm3 (natural gas, NG) at standard conditions, were achieved by blending NG with CO2 as diluent. Emissions, combustion dynamics, fuel pressure, and flashback monitoring via measurement of burner metal temperatures, were the main parameters used to evaluate the impact of fuel flexibility on combustor performance. Test results show that NOx emissions decrease as the fuel heating value is reduced. Also note that a decreasing fuel heating value leads to a requirement to increase the fuel supply pressure. Effect of fuel heating value on combustion was investigated, and the reduction in adiabatic flame temperature and laminar flame speed was observed for lower heating value fuels. The successful development program has increased the capability of the SGT-400 standard production dry low emissions (DLE) burner configuration to operate with a range of fuels covering a WI corrected to the normal conditions from 30 MJ/N·m3 to 49 MJ/N·m3. The tests results obtained on the Siemens SGT-400 combustion system provide significant experience for industrial gas turbine burner design for fuel flexibility.

Extension of Fuel Flexibility in the Siemens Dry Low Emissions SGT-300-1S to Cover a Wobbe Index Range of 15 to 49 MJ/m3

2012 ◽  
Author(s):  
Kexin Liu ◽  
Varkey Alexander ◽  
Victoria Sanderson ◽  
Ghenadie Bulat
Keyword(s):  
Natural Gas ◽  
Nox Reduction ◽  
Operating Conditions ◽  
Combustion System ◽  
Combustion Dynamics ◽  
Fuel Supply ◽  
Supply Pressure ◽  
Fuel Flexibility ◽  
Wobbe Index ◽  
Standard Production

The extension of gas fuel flexibility in the Siemens SGT-300 single shaft (SGT-300-1S) is reported in this paper. A successful development programme has increased the capability of the Siemens Industrial Turbomachinery, Lincoln (SITL) dry low emissions (DLE) burner configuration to a fuel range covering a Wobbe Index (WI) from 15 to 49 MJ/m3. The standard SGT-300-1S SITL DLE combustion hardware allowed for gas and liquid fuels within a specified range typically associated with natural gas and diesel, respectively. Field operation of the standard production SGT-300-1S has confirmed the reliable operation with an extension to the fuels range to include processed land fill gas (PLG) from 32 to 49 MJ/m3. The further extension of the fuel range for the SGT-300-1S SITL DLE combustion system was achieved through high pressure testing of a single combustion system at engine operating conditions. The rig facility allowed for the actual fuel type to be tested using a mixing plant. The variations in fuel heating value were achieved by blending natural gas with diluent CO2 and/or N2. Various diagnostics were used to assess the performance of the combustion system including measurement of combustion dynamics, temperature, fuel supply pressure and emissions of NOx, CO and unburned hydrocarbon (UHC). The results of the testing showed that the standard production burner can operate for a fuel with WI as low as 23 MJ/m3 which corresponds to 35% CO2 (in volume) in the fuel. This range can be extended to 15 MJ/m3 (54.5% CO2 in the fuel) with only minor modification, to control losses through the burner and to maintain similar fuel injection characteristics. The SITL DLE combustion system is able to cover a WI range of 15 to 49 MJ/m3 in two configurations. The results of testing showed a lowering in WI, from diluting with CO2 and/or N2, a benefit in NOx reduction is observed. This decrease in WI may lead to an increased requirement in fuel supply pressure.

LNG Interchangeability in Land Based Gas Turbines: The Siemens Approach

2007 ◽  
Author(s):  
Pratyush Nag ◽  
Khalil Abou-Jaoude ◽  
Steve Mumford ◽  
Jianfan Wu ◽  
Matthew LaGrow ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Warning System ◽  
Fuel Composition ◽  
Combustion System ◽  
Fuel Gas ◽  
Combustion Dynamics ◽  
Site Specific ◽  
Fuel Characteristics ◽  
Combustion Systems

Liquefied Natural Gas (LNG) from offshore reserves is expected to expand its role in supplementing US natural gas supplies. The quality and hydrocarbon contents of the natural gas imported from these international sources, frequently differs from the compositions of domestic natural gas. With the range of variations in fuel characteristics known to exist with offshore LNG, use of this LNG in gas turbine engines could violate applicable fuel specifications, and lead to operational issues such as, but not limited to, combustion dynamics, flashback, increased emissions, or decreased component life. Another potential issue for gas turbines generating power is that rapid changes in the fuel characteristics that may occur when blending imported and domestic gas, may lead to substantial fluctuations in power output. Fuel flexibility is dominantly tied to the combustion system design. Conventional diffusion flame combustion systems are more tolerant of wide variations in fuel compositions but they are limited by their emission levels. The more advanced premixed flame combustors, the Dry Low NOxs (DLN) and Ultra Low NOx (ULN) combustion systems have significantly better performances in terms of emissions but they are also more sensitive to changes in the fuel composition and characteristics. Siemens has performed test campaigns with commercially operating engines and high pressure combustion test rigs to evaluate their commercially available combustion system configurations for LNG applicability. From these test campaigns, Siemens has defined the set of combustion hardware modifications which is robust to changes in fuel composition within the tested limits. Along with the said combustion hardware upgrade, Siemens has also designed an Integrated Fuel Gas Characterization (IFGC) system (Patent Pending). This IFGC system acts like an early warning system and feeds forward signals into the plant control system. Depending on the changes in the properties of the incoming fuel, the IFGC system is designed to adjust the engine tuning settings to compensate for these dynamic changes in the fuel. Customer implementation of the required hardware as well as associated site-specific engineering will mitigate the operational and emissions risk associated with the fuel changes. Overall, it is Siemens recommendation that LNG type fuels will be acceptable to be used in Siemens Gas Turbines with the preferred combustion hardware in place along with the Integrated Fuel Gas Characterization System. A site specific evaluation would be required to determine the optimal system depending on the expected fuels that the unit would be operating with, along with the emissions permit levels associated with the site.

Pentane Rich Fuels for Standard Siemens DLE Gas Turbines

2011 ◽  
Author(s):  
Mats Andersson ◽  
Anders Larsson ◽  
Arturo Manrique Carrera
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Dynamics ◽  
Heating Value ◽  
Special Adaptation ◽  
Fuel Flexibility ◽  
Combustion Properties ◽  
Model Substance ◽  
Wobbe Index

Associated gases at oil wells are often rich in heavy hydrocarbons (HHC, here denoting hydrocarbons heavier than propane). HHC cause handling difficulties and the combustion properties are quite different from standard natural gas. For this and other reasons HHC rich associated gases are often flared or vented. This is an enormous waste of useable energy and a significant contribution to emissions of pollutants, global CO2 and other greenhouse gases. Siemens Industrial Turbomachinery AB in Finspong (SIT AB) recently tested a standard DLE 25 MW SGT-600 gas turbine and a standard 31 MW SGT-700 gas turbine with HHC rich natural gas. Pentane was chosen as a model substance for HHC. The tested gases had up to 30% of the fuel heating value from pentane. The unmodified standard DLE gas turbines proved to be very tolerant to the tested pentane rich gases. CO emissions were reduced with increasing pentane content in the fuel for the same power output. NOx was observed to increase linearly with the pentane content. Combustion dynamics was affected mildly, but noticeably by the pentane rich fuel. This result, together with earlier presented results for the same DLE engines on nitrogen rich natural gases, gives an accepted and tested total LHV range of 25–50 MJ/kg and Wobbe index range of 25–55 MJ/Nm3. No special adaptation of the gas turbines was necessary for allowing this wide fuel range. The benefit of increased and proven fuel flexibility is obvious as it allows the gas turbine owner to make full use of opportunity fuels and to supply power at low fuel cost.

Extension of Fuel Flexibility in the Siemens Dry Low Emissions SGT-300-1S to Cover a Wobbe Index Range of 15 to 49 MJ/Sm3

2013 ◽  
Vol 135 (2) ◽  
Author(s):  
Kexin Liu ◽  
Varkey Alexander ◽  
Victoria Sanderson ◽  
Ghenadie Bulat
Keyword(s):  
Natural Gas ◽  
Nox Reduction ◽  
Operating Conditions ◽  
Combustion System ◽  
Combustion Dynamics ◽  
Fuel Supply ◽  
Supply Pressure ◽  
Fuel Flexibility ◽  
Wobbe Index ◽  
Standard Production

The extension of gas fuel flexibility in the Siemens SGT-300 single shaft (SGT-300-1S) is reported. A successful development program has increased the capability of the Siemens Industrial Turbomachinery, Lincoln (SITL) dry low emissions (DLE) burner configuration to a fuel range covering a Wobbe index (WI) from 15 to 49 MJ/Sm3. The WI reported in this paper is at a 15 °C fuel temperature. The standard SGT-300-1S SITL DLE combustion hardware allows for gas and liquid fuels within a specified range typically associated with natural gas and diesel, respectively. The range of the WI associated with natural gas is 37–49 MJ/Sm3. Field operation of the standard production SGT-300-1S has confirmed the reliable operation with an extension to the fuels range to include processed landfill gas (PLG) from 30 to 49 MJ/Sm3. The further extension of the fuel range for the SGT-300-1S SITL DLE combustion system was achieved through high pressure testing of a single combustion system at engine operating conditions and representative fuels. The variations in the fuel heating value were achieved by blending natural gas with diluent CO2 and/or N2. Various diagnostics were used to assess the performance of the combustion system, including the measurement of combustion dynamics, temperature, fuel supply pressure, and the emissions of NOx, CO, and unburned hydrocarbons (UHCs). The results of the testing showed that the standard production burner can operate for a fuel with a WI as low as 23 MJ/Sm3, which corresponds to 35% CO2 (by volume) in the fuel. This range can be extended to 15 MJ/Sm3 (54.5% CO2 in the fuel) with only minor modification to control losses through the burner and to maintain similar fuel injection characteristics. The SITL DLE combustion system is able to cover a WI range of 15 to 49 MJ/Sm3 in two configurations. The results of testing showed a lowering in the WI, by diluting with CO2 and/or N2, so that a benefit in the NOx reduction is observed. This decrease in the WI may lead to an increased requirement of the fuel supply pressure.

Performance Prediction of Gas Turbine Under Different Strategies Using Low Heating Value Fuel

2013 ◽  
Author(s):  
Edson Batista da Silva ◽  
Marcelo Assato ◽  
Rosiane Cristina de Lima
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Equivalence Ratio ◽  
Safe Operation ◽  
Engine Operation ◽  
Heating Value ◽  
Gasification Process ◽  
Surge Margin ◽  
And Performance ◽  
Industrial Gas Turbine

Usually, the turbogenerators are designed to fire a specific fuel, depending on the project of these engines may be allowed the operation with other kinds of fuel compositions. However, it is necessary a careful evaluation of the operational behavior and performance of them due to conversion, for example, from natural gas to different low heating value fuels. Thus, this work describes strategies used to simulate the performance of a single shaft industrial gas turbine designed to operate with natural gas when firing low heating value fuel, such as biomass fuel from gasification process or blast furnace gas (BFG). Air bled from the compressor and variable compressor geometry have been used as key strategies by this paper. Off-design performance simulations at a variety of ambient temperature conditions are described. It was observed the necessity for recovering the surge margin; both techniques showed good solutions to achieve the same level of safe operation in relation to the original engine. Finally, a flammability limit analysis in terms of the equivalence ratio was done. This analysis has the objective of verifying if the combustor will operate using the low heating value fuel. For the most engine operation cases investigated, the values were inside from minimum and maximum equivalence ratio range.

Fuel Flexibility Influences on Premixed Combustor Blowout, Flashback, Autoignition and Instability

2006 ◽  
Author(s):  
Tim Lieuwen ◽  
Vince McDonell ◽  
Eric Petersen ◽  
Domenic Santavicca
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Dynamic Stability ◽  
Current Understanding ◽  
Fuel Composition ◽  
Fuel Flexibility ◽  
Lean Premixed ◽  
Gas Fuel ◽  
The Impact ◽  
Underlying Processes

This paper addresses the impact of fuel composition on the operability of lean premixed gas turbine combustors. This is an issue of current importance due to variability in the composition of natural gas fuel supplies and interest in the use of syngas fuels. Of particular concern is the effect of fuel composition on combustor blowout, flashback, dynamic stability, and autoignition. This paper reviews available results and current understanding of the effects of fuel composition on the operability of lean premixed combustors. It summarizes the underlying processes that must be considered when evaluating how a given combustor’s operability will be affected as fuel composition is varied.

Impact of Ethane, Propane, and Diluent Content in Natural Gas on the Performance of a Commercial Microturbine Generator

2008 ◽  
Vol 130 (1) ◽  
Author(s):  
Richard L. Hack ◽  
Vincent G. McDonell
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Fuel Composition ◽  
Nox Emissions ◽  
Heating Value ◽  
Designed Experiment ◽  
Methane Number ◽  
The Impact ◽  
Lean Conditions

The impact of fuel composition on the performance of power generation devices is gaining interest as the desire to diversify fuel supplies increases. In the present study, measurements of combustion performance were conducted on a commercial natural gas-fired 60kW gas turbine as a function of fuel composition. A statistically designed experiment was carried out and exhaust emissions were obtained for significant amounts of ethane and propane. In addition, a limited study of the effect of inerts was conducted. The results show that emissions of NOx, CO, and NOx∕NO are not well correlated with common descriptions of the fuel, such as higher heating value or methane number. The results and trends indicate that the presence of higher hydrocarbons in the fuel leads to appreciably higher NOx emissions for both test devices operating under similar lean conditions, while having less impact on CO emissions.

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