Firing Trials of the Siemens SGT-300 Dry Low Emissions Combustion System Using High Calorific Value Fuels

Author(s):  
Kristopher Calladine ◽  
Jim Rogerson ◽  
Phill Hubbard ◽  
Suresh K. Sadasivuni ◽  
Ghenadie Bulat

Abstract The current paper presents an extension of the fuel flexibility of the Siemens SGT-300 Dry Low Emissions combustion system to include High Calorific Value fuels, achieved using the engine’s current standard combustion hardware. Results from high pressure rig tests show that the standard SGT-300 DLE combustor can reliably operate on High Calorific Value fuels with temperature corrected Wobbe Index up to 63MJ/m3, which corresponds to Grade A LPG (60%vol. C3H8, 40%vol. C4H10). Metal temperatures of the combustion hardware when operating on High Calorific Value fuels are within life acceptance criteria for the Siemens SGT-300 industrial gas turbine. NOx emissions throughout the load range of the engine comply with the EU Industrial Emissions Directive. At part load, a reduced requirement for piloting compared to Natural Gas yields relatively low temperatures at the burner face and low NOx emissions. NOx emissions at full load, which tend to increase with increasing heating value, are higher than for Natural Gas but lower than for diesel and heavy fuel oils.

Author(s):  
Phill Hubbard ◽  
Kexin Liu ◽  
Suresh Sadasivuni ◽  
Ghenadie Bulat

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.


Author(s):  
K. O. Smith ◽  
A. Fahme

Three subscale, cylindrical combustors were rig tested on natural gas at typical industrial gas turbine operating conditions. The intent of the testing was to determine the effect of combustor liner cooling on NOx and CO emissions. In order of decreasing liner cooling, a metal louvre-cooled combustor, a metal effusion-cooled combustor, and a backside-cooled ceramic (CFCC) combustor were evaluated. The three combustors were tested using the same lean-premixed fuel injector. Testing showed that reduced liner cooling produced lower CO emissions as reaction quenching near the liner wall was reduced. A reduction in CO emissions allows a reoptimization of the combustor air flow distribution to yield lower NOx emissions.


2004 ◽  
Vol 128 (2) ◽  
pp. 247-254 ◽  
Author(s):  
Jochen R. Kalb ◽  
Thomas Sattelmayer

The technological objective of this work is the development of a lean-premixed burner for natural gas. Sub-ppm NOx emissions can be accomplished by shifting the lean blowout limit (LBO) to slightly lower adiabatic flame temperatures than the LBO of current standard burners. This can be achieved with a novel burner concept utilizing spatially periodic recirculation of combustion products: Hot combustion products are admixed to the injected premixed fresh mixture with a mass flow rate of comparable magnitude, in order to achieve self-ignition. The subsequent combustion of the diluted mixture again delivers products. A fraction of these combustion products is then admixed to the next stream of fresh mixture. This process pattern is to be continued in a cyclically closed topology, in order to achieve stable combustion of, for example, natural gas in a temperature regime of very low NOx production. The principal ignition behavior and NOx production characteristics of one sequence of the periodic process was modeled by an idealized adiabatic system with instantaneous admixture of partially or completely burnt combustion products to one stream of fresh reactants. With the CHEMKIN-II package, a reactor network consisting of one perfectly stirred reactor (PSR, providing ignition in the first place) and two plug flow reactors (PFR) has been used. The effect of varying burnout and the influence of the fraction of admixed flue gas has been evaluated. The simulations have been conducted with the reaction mechanism of Miller and Bowman and the GRI-Mech 3.0 mechanism. The results show that the high radical content of partially combusted products leads to a massive decrease of the time required for the formation of the radical pool. As a consequence, self-ignition times of 1 ms are achieved even at adiabatic flame temperatures of 1600 K and less, if the flue gas content is about 50–60% of the reacting flow after mixing is complete. Interestingly, the effect of radicals on ignition is strong, outweighs the temperature deficiency and thus allows stable operation at very low NOx emissions.


Author(s):  
K. Michael Düsing ◽  
Andrea Ciani ◽  
Urs Benz ◽  
Adnan Eroglu ◽  
Klaus Knapp

The recent development of the Alstom’s sequential combustion system for the GT24 (60Hz) and GT26 (50Hz) upgrades 2011 is a perfect example of evolutionary design optimizations. Better overall performance is achieved through improved SEV burner aerodynamics and fuel injection, while keeping the main features of the sequential burner technology. In particular this results in further reduced NOx and CO emissions over widest possible load range and allows operation with fuel gases with up to 18% of higher hydrocarbons (C2+) or a low Wobbe index. An extensive validation of the new sequential burners for GT24 and GT26 has been conducted, with a wide range of validation tools. This has included high pressure sector rig testing and full-engine tests at the Alstom Power Plant Birr, Switzerland. This paper presents the development and validation process, in terms of evolutionary design modifications and successful burner scaling, of the GT24 and GT26 (upgrades 2011) reheat combustors from concept phase to engine validation.


Author(s):  
Kexin Liu ◽  
Varkey Alexander ◽  
Victoria Sanderson ◽  
Ghenadie Bulat

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.


Author(s):  
Marcus H. H. Scholz ◽  
Simon M. DePietro

The second Generation of EGT’s G30 DLE combustion system was introduced after a successful series of high pressure rig and engine tests. This paper covers how operational problems with field commissioning hardware on the lead DLN machine were dealt with, leading to achievement of reliable low NOx hardware. Several changes were applied to the early design which improved the mixing and reduced the effects of high temperature distortion and combustor dynamics. This resulted in increased life of the burner and changed the characteristics of dynamics. It also led to very low emission levels with an outstanding capability for turndown of CO with NOx below 25 ppmvd (15% O2) over the whole load range. Further coverage is given to the effect of field tuning, and of fuel composition on the amplitudes and frequencies of dynamics. The installation has been supported by on-line condition monitoring of engine parameters, emission levels and ambient conditions, which are also discussed. The general overview of site history is followed by a summary of lessons learnt in field comparison to development test bed.


Author(s):  
Kenneth O. Smith ◽  
Leonard C. Angello ◽  
F. Richard Kurzynske

The design and initial rig testing of an ultra-low NOx gas turbine combustor primary zone are described. A lean premixed, swirl-stabilized combustor was evaluated over a range of pressures up to 10.7 × 105 Pa (10.6 atm) using natural gas. The program goal of reducing NOx emissions to 10 ppm (at 15% O2) with coincident low CO emissions was achieved at all combustor pressure levels. Appropriate combustor loading for ultra-low NOx operation was determined through emissions sampling within the primary zone. The work described represents a first step in developing an advanced gas turbine combustion system that can yield ultra-low NOx levels without the need for water injection and selective catalytic reduction.


Author(s):  
M. C. Fernández-Feal ◽  
B. Sánchez-Fernández ◽  
L. R. Sánchez-Fernández ◽  
J. R. Pérez-Prado

Aims: To assess the composition of the Natural Gas (NG) supplied for domestic consumption through the distribution network to correlate the physical properties linked to it were to be determined in order to investigate their fluctuations. Study Design:  The samples were analyzed in accordance with the method described in the ISO 6974‑4 standard, “Natural Gas. Determination of Composition with Defined Uncertainty by Gas Chromatography”. Place and Duration of Study: Center of Technology Research, Fuels Laboratory, between January and December 2016. Methodology: Over the course of the year, a total of eighty-four samples of natural gas for domestic use were analyzed.  These were collected at a rate of one per month in seven cities in the geographical zone under study (Galicia_Spain), in which the number of users is significant. Results and Conclusion: The protocols for technical management of the Gas System have a section on quality specifications for Natural Gas at entry points to the system.  This sets limits for only three of the physical properties of natural gas: Wobbe index, superior calorific value and relative density. The figures obtained for Wobbe index, superior calorific value and relative density from the eighty-four samples studied showed that the quality of the Natural Gas distributed remained steadily within the acceptable limits throughout the whole year. The values for standard deviations bore witness to the fact that any variations did not significantly alter the quality of the Natural Gas supplied. The concentrations of the odorant, THT, were always above the recommended value of 18.0 mg/Nm3, the fluctuations noted over the course of the year were such as to make it possible to see them as excessive. In some instances, a high concentration of odorant may lead users to erroneous impressions, so that they come to think that there are leaks from the gas-pipes or even that the gas is not burning properly.


Author(s):  
Dimitri Namgaladze ◽  
Tornike Kiziria ◽  
Lena Shatakishvili ◽  
Tamaz Ghvanidze

The increase in the cost of energy and the appearance of gases of various qualities led to the fact that calculations in the gas industry began to be made by measuring thermal energy.  To this day, in Georgia, the calculation of the amount of natural gas when paying for the used gas is in cubic meters.  As for the study of processes and parameters in the Georgian gas sector, it turned out that these processes are clearly stochastic.  Therefore, the purpose of the work is to develop criteria for the interchangeability of natural gas, in particular, a diagram of the interaction between the Wobbe index in total proportions of propane and nitrogen equivalent for the Georgian gas market, based on stochastic processes.  Thus, for the first time, an original methodology for plotting the Wobbe Index (calorific value) of interchangeable natural gases supplied to Georgia was developed.


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