Sequential Combustion in Gas Turbines: The Key Technology for Burning High Hydrogen Contents With Low Emissions

2019 ◽  
Author(s):  
Mirko R. Bothien ◽  
Andrea Ciani ◽  
John P. Wood ◽  
Gerhard Fruechtel
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Tuning Parameter ◽  
High Hydrogen ◽  
Stable Combustion ◽  
Second Stage ◽  
In Series ◽  
Exit Temperature

Abstract Excess energy generation from renewables can be conveniently stored as hydrogen for later use as a gas turbine fuel. Also, the strategy to sequestrate CO2 from natural gas will require gas turbines to run with hydrogen-based fuels. In such scenarios, high temperature low emission combustion of hydrogen is a key requirement for the future gas turbine market. Ansaldo Energia’s gas turbines featuring sequential combustion have an intrinsic advantage when it comes to fuel flexibility and in particular hydrogen-based fuels. The sequential combustion system is composed of two complementary combustion stages in series: one premix stage followed by an auto-ignited second stage overcoming the limits of traditional premix combustion systems through a highly effective extra tuning parameter, i.e. the temperature between the first and the second stage. The standard Constant Pressure Sequential Combustion (CPSC) system as applied in the GT36 engine is tested, at high pressure, demonstrating that a modified operation concept allows stable combustion with no changes in combustor hardware for the whole range of natural gas and hydrogen blends. It is shown that in the range from 0% to 70% (vol.) hydrogen, stable combustion is achieved at full nominal exit temperature, i.e. without any derating and thus clearly outperforming other available conventional premixed combustors. Operation between 70% and 100% is possible as well and only requires a mild reduction of the combustor exit temperature. By proving the transferability of the single-can high pressure results to the engine, this paper demonstrates the practicality of operating the Ansaldo Energia GT36 H-Class gas turbine on fuels containing unprecedented concentrations of hydrogen while maintaining excellent performance and low emissions both in terms of NOx and CO2.

Toward Decarbonized Power Generation With Gas Turbines by Using Sequential Combustion for Burning Hydrogen

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
Mirko R. Bothien ◽  
Andrea Ciani ◽  
John P. Wood ◽  
Gerhard Fruechtel
Keyword(s):  
High Pressure ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Tuning Parameter ◽  
Stable Combustion ◽  
Second Stage ◽  
Fuel Flexibility ◽  
Mild Reduction ◽  
In Series ◽  
Exit Temperature

Abstract Excess energy generation from renewables can be conveniently stored as hydrogen for later use as a gas turbine fuel. Also, the strategy to sequestrate CO2 from natural gas (NG) will require gas turbines to run with hydrogen-based fuels. In such scenarios, high temperature low emission combustion of hydrogen is a key requirement for the future gas turbine market. Ansaldo Energia's gas turbines featuring sequential combustion have an intrinsic advantage when it comes to fuel flexibility and in particular hydrogen-based fuels. The sequential combustion system is composed of two complementary combustion stages in series: one premix stage followed by an auto-ignited second stage overcoming the limits of traditional premix combustion systems through a highly effective extra tuning parameter, i.e., the temperature between the first and the second stage. The standard constant pressure sequential combustion (CPSC) system as applied in the GT36 engine is tested, at high pressure, demonstrating that a modified operation concept allows stable combustion with no changes in combustor hardware for the whole range of NG and hydrogen blends. It is shown that in the range from 0% to 70% (vol.) hydrogen, stable combustion is achieved at full nominal exit temperature, i.e., without any derating and thus clearly outperforming other available conventional premixed combustors. Operation between 70% and 100% is possible as well and only requires a mild reduction of the combustor exit temperature. By proving the transferability of the single-can high pressure results to the engine, this paper demonstrates the practicality of operating the Ansaldo Energia GT36 H-Class gas turbine on fuels containing unprecedented concentrations of hydrogen while maintaining excellent performance and low emissions both in terms of NOx and CO2.

Performance and Cost Analysis of Advanced Gas Turbine Cycles With Precombustion CO2 Capture

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Stéphanie Hoffmann ◽  
Michael Bartlett ◽  
Matthias Finkenrath ◽  
Andrei Evulet ◽  
Tord Peter Ursin
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Co2 Capture ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Co2 Separation ◽  
The Cost

This paper presents the results of an evaluation of advanced combined cycle gas turbine plants with precombustion capture of CO2 from natural gas. In particular, the designs are carried out with the objectives of high efficiency, low capital cost, and low emissions of carbon dioxide to the atmosphere. The novel cycles introduced in this paper are comprised of a high-pressure syngas generation island, in which an air-blown partial oxidation reformer is used to generate syngas from natural gas, and a power island, in which a CO2-lean syngas is burnt in a large frame machine. In order to reduce the efficiency penalty of natural gas reforming, a significant effort is spent evaluating and optimizing alternatives to recover the heat released during the process. CO2 is removed from the shifted syngas using either CO2 absorbing solvents or a CO2 membrane. CO2 separation membranes, in particular, have the potential for considerable cost or energy savings compared with conventional solvent-based separation and benefit from the high-pressure level of the syngas generation island. A feasibility analysis and a cycle performance evaluation are carried out for large frame gas turbines such as the 9FB. Both short-term and long-term solutions have been investigated. An analysis of the cost of CO2 avoided is presented, including an evaluation of the cost of modifying the combined cycle due to CO2 separation. The paper describes a power plant reaching the performance targets of 50% net cycle efficiency and 80% CO2 capture, as well as the cost target of 30$ per ton of CO2 avoided (2006 Q1 basis). This paper indicates a development path to this power plant that minimizes technical risks by incremental implementation of new technology.

Evaluation of CH4/NOx Reduced Mechanisms Used for Modeling Lean Premixed Turbulent Combustion of Natural Gas

1998 ◽  
Vol 120 (4) ◽  
pp. 703-712 ◽  
Author(s):  
H. P. Mallampalli ◽  
T. H. Fletcher ◽  
J. Y. Chen
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Turbulent Combustion ◽  
Gas Turbines ◽  
Flame Structure ◽  
Computational Cost ◽  
Premixed Turbulent Combustion ◽  
Reduced Mechanism ◽  
Lean Premixed

This study has identified useful reduced kinetic schemes that can be used in comprehensive multidimensional gas-turbine combustor models. Reduced mechanisms lessen computational cost and possess the capability to accurately predict the overall flame structure, including gas temperatures and key intermediate species such as CH4, CO, and NOx. In this study, four new global mechanisms with five, six, seven, and nine steps based on the full GRI 2.11 mechanism, were developed and evaluated for their potential to model natural gas chemistry (including NOx chemistry) in gas turbine combustors. These new reduced mechanisms were optimized to model the high pressure and fuel-lean conditions found in gas turbines operating in the lean premixed mode. Based on perfectly stirred reactor (PSR) and premixed code calculations, the five-step reduced mechanism was identified as a promising model that can be used in a multidimensional gas-turbine code for modeling lean-premixed, high-pressure turbulent combustion of natural gas. Predictions of temperature, CO, CH4, and NO from the five-to nine-step reduced mechanisms agree within 5 percent of the predictions from the full kinetic model for 1 < pressure (atm) < 30, and 0.6 < φ < 1.0. If computational costs due to additional global steps are not severe, the newly developed nine step global mechanism, which is a little more accurate and provided the least convergence problems, can be used. Future experimental research in gas turbine combustion will provide more accurate data, which will allow the formulation of better full and reduced mechanisms. Also, improvement in computational approaches and capabilities will allow the use of reduced mechanisms with larger global steps, perhaps full mechanisms.

scholarly journals Development and Integration of the Dual Fuel Combustion System for the MGT Gas Turbine Family

2021 ◽  
Author(s):  
Bernhard Ćosić ◽  
Frank Reiß ◽  
Marc Blümer ◽  
Christian Frekers ◽  
Franklin Genin ◽  
...  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Distribution System ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Flame Stabilization ◽  
Experimental Investigations ◽  
Dual Fuel ◽  
Combustion System

Abstract Industrial gas turbines like the MGT6000 are often operated as power supply or as mechanical drives for pumps and compressors at remote locations on islands and in deserts. Moreover, small gas turbines are used in CHP applications with a high need for availability. In these applications, liquid fuels like ‘Diesel Fuel No. 2’ can be used either as main fuel or as backup fuel if natural gas is not reliably available. The MAN Gas Turbines (MGT) operate with the Advanced Can Combustion (ACC) system, which is already capable of ultra-low NOx emissions for a variety of gaseous fuels. This system has been further developed to provide dry dual fuel capability to the MGT family. In the present paper, we describe the design and detailed experimental validation process of the liquid fuel injection, and its integration into the gas turbine package. A central lance with an integrated two-stage nozzle is employed as a liquid pilot stage, enabling ignition and start-up of the engine on liquid fuel only, without the need for any additional atomizing air. The pilot stage is continuously operated to support further the flame stabilization across the load range, whereas the bulk of the liquid fuel is injected through the premixed combustor stage. The premixed stage comprises a set of four decentralized nozzles placed at the exit of the main air swirler. These premixed nozzles are based on fluidic oscillator atomizers, wherein a rapid and effective atomization of the liquid fuel is achieved through self-induced oscillations of the liquid fuel stream. We present results of numerical and experimental investigations performed in the course of the development process illustrating the spray, hydrodynamic, and thermal performance of the pilot injectors. Extensive testing of the burner at atmospheric and full load high-pressure conditions has been performed, before verification of the whole combustion system within full engine tests. The burner shows excellent emission performance (NOx, CO, UHC, soot) without additional water injection, while maintaining the overall natural gas performance. Soot and particle emissions, quantified via several methods, are well below legal restrictions. Furthermore, when not in liquid fuel operation, a continuous purge of the injectors based on compressor outlet (p2) air has been laid out. Generic atmospheric coking tests were conducted before verifying the purge system in full engine tests. Thereby we completely avoid the need for an additional high-pressure auxiliary compressor or demineralized water. We show the design of the fuel supply and distribution system. We designed it to allow for rapid fuel switchovers from gaseous fuel to liquid fuel, and for sharp load jumps. Finally, we discuss the integration of the dual fuel system into the standard gas turbine package of the MGT6000 in detail.

Performance and Cost Analysis of Advanced Gas Turbine Cycles With Pre-Combustion CO2 Capture

2008 ◽  
Author(s):  
Ste´phanie Hoffmann ◽  
Michael Bartlett ◽  
Matthias Finkenrath ◽  
Andrei Evulet ◽  
Tord Peter Ursin
Keyword(s):  
High Pressure ◽  
Power Plant ◽  
Natural Gas ◽  
Gas Turbine ◽  
Co2 Capture ◽  
Gas Turbines ◽  
High Efficiency ◽  
Combined Cycle ◽  
Co2 Separation ◽  
The Cost

This paper presents the results of an evaluation of advanced combined cycle gas turbine plants with pre-combustion capture of CO2 from natural gas. In particular, the designs are carried out with the objectives of high efficiency, low capital cost and low emissions of carbon dioxide to the atmosphere. The novel cycles introduced in this paper are comprised of a high-pressure syngas generation island, in which an air-blown POX reformer is used to generate syngas from natural gas, and a power island, in which a CO2-lean syngas is burnt in a large frame machine. In order to reduce the efficiency penalty of natural gas reforming, a significant effort is spent evaluating and optimizing alternatives to recover the heat released during the process. CO2 is removed from the shifted syngas using either CO2 absorbing solvents or a CO2 membrane. CO2 separation membranes, in particular, have the potential for considerable cost or energy savings compared to conventional solvent-based separation and benefit from the high pressure level of the syngas generation island. A feasibility analysis and a cycle performance evaluation are carried out for large frame gas turbines such as the 9FB. Both short term and long term solutions have been investigated. An analysis of the cost of CO2 avoided is presented, including an evaluation of the cost of modifying the combined cycle due to CO2 separation. The paper describes a power plant reaching the performance targets of 50% net cycle efficiency and 80% CO2 capture, as well as the cost target of 30$ per ton of CO2 avoided. This paper indicates a development path to this power plant that minimizes technical risks by incremental implementation of new technology.

scholarly journals Improvement of the turn-down ratio of gas turbines by autothermal on board syngas generation

2017 ◽  
Vol 1 ◽  
pp. D0HPA5 ◽  
Author(s):  
Max H. Baumgärtner ◽  
Thomas Sattelmayer
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Equivalence Ratio ◽  
Burning Velocity ◽  
Combined Cycle ◽  
Sudden Increase ◽  
High Hydrogen ◽  
Fuel Processor ◽  
Burn Out

Abstract The low reactivity of natural gas leads to a sudden increase of carbon monoxide (CO) and unburned hydrocarbons (UHC) emissions below a certain load level, which limits the part load operation range of current utility gas turbines in combined cycle power plants (CCPP). The feasibility of catalytic autothermal syngas generation directly upstream of gas turbine burners to improve burn-out at low flame temperatures is studied in this paper. The adiabatic reformer is supplied with a mixture of natural gas, air and water and generates syngas with high reactivity, which results in better low-temperature combustion performance. Substitution of part of the natural gas by syngas provides the opportunity of lowering overall equivalence ratio in the combustion chamber and of extending the operation range towards lower minimum power output without violating emission limits. A generic gas turbine with a syngas generator is modelled by analytic equations to identify the possible operating window of a fuel processor constrained by pressure loss, low and high temperature limits and carbon formation. A kinetic study shows good conversion of methane to syngas with a high hydrogen share. A calculation of the one-dimensional laminar burning velocity of mixtures of syngas and methane and the assessment of the corresponding Damköhler number show the potential for lowering the minimum equivalence ratio with full burn-out by fuel processing. The study shows that such a fuel processor has a possible operating range despite the before mentioned constraints and it has potential to reduce the lowest possible load of gas turbines in terms of thermal power by 20%.

Operation of SGT-600 (24 MW) DLE Gas Turbine With Over 60 % H2 in Natural Gas

2020 ◽  
Author(s):  
Rikard Magnusson ◽  
Mats Andersson
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Full Scale ◽  
Test Facility ◽  
Major Constituent ◽  
Major Step ◽  
High Hydrogen ◽  
Flow Capacity ◽  
Small Series

Abstract Hydrogen is one of the leading options for storing energy from renewables and surplus electricity. Hydrogen is also a major constituent in various streams in the chemical industry and cannot always be used for better purposes than flaring or heat and power generation. Siemens has identified the 24MWe SGT-600 3rd generation DLE gas turbine as a candidate for having a high hydrogen capability. The burners for using hydrogen in the SGT-600 have been developed for and by Additive Manufacturing technology. The advantages of this technology have been integrated into the presented design and therefore allowing: • Rapid prototyping with possibilities for fast turnaround of tests and screening of various concepts • Manufacturing of complex geometries with smart gas passages, very innovative cooling and mixing concepts • Small series and minimum waste with reduced cost • Good repeatability and stability of product quality Burner development was carried out according to “the standard method within the industry”, meaning CFD-analysis, atmospheric single burner combustion testing followed by pressurized single burner combustion testing and finally a full-scale machine test at the SIEMENS Industrial Turbomachinery AB (SIT) test rig facility in Sweden. The rig is used for full scale testing of gas turbines in the power output range from 15MW to 62MW. It allows testing not only with standard natural gas but also gas mixtures with e.g. hydrogen or nitrogen can be run. The test facility has liquid fuel capability. During the burner development process, a project including two SGT-600 running on up to 60 volume % hydrogen was awarded to Siemens. This meant that a very definite target for the development was set and the results of these efforts are presented in this paper. An adapted 3rd gen. DLE burner design proved to be capable of using 100% hydrogen at SGT-600 full load conditions at the single burner high pressure tests giving only 35 ppm NOx@15%O2. This was a major step in the development of a hydrogen burner for the SGT-600. The following full engine test with the same burner type showed the possibility to run with 60 vol-% H2 at 0–100% load while keeping stable combustion and achieving emissions below 25 ppm NOx@15%O2 in the standard operating range of the SGT-600. At lower loads higher hydrogen contents were tested (95 vol-%) but the flow capacity of the fuel system limited the full exploration of hydrogen capability of the SGT-600 3rd gen. DLE gas turbine. The 3rd gen. DLE burner is also used in the 33MWe SGT-700 and the 62MWe SGT-800, which will also benefit from the development of the increased SGT-600 hydrogen capability. The results open the possibility of using H2 rich gas more widely in all gas turbine configurations using 3rd gen. DLE burner.

scholarly journals Staged combustion concept for gas turbines

2017 ◽  
Vol 1 ◽  
pp. CVLCX0 ◽  
Author(s):  
Dieter Winkler ◽  
Weiqun Geng ◽  
Geoffrey Engelbrecht ◽  
Peter Stuber ◽  
Klaus Knapp ◽  
...  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Cross Flow ◽  
Staged Combustion ◽  
Cfd Simulations ◽  
Flow Configuration ◽  
Turbulent Flame Speed ◽  
Second Stage ◽  
Jet In Cross Flow

AbstractGas turbine power plants with high load flexibility are particularly suitable to compensate power fluctuations of wind and solar plants. Conventional gas turbines suffer from higher emissions at low load operation. With the objective of improving this situation a staged combustion system has been investigated. At low gas turbine load an upstream stage (first stage) provides stable combustion at low emissions while at higher loads the downstream stage (second stage) is started to supplement the power. Three injection geometries have been studied by means of computational fluid dynamics (CFD) simulations and atmospheric tests. The investigated geometries were a simple annular gap, a jet-in-cross-flow configuration and a lobe mixer. With CFD simulations the quality of mixing of second stage fresh gas with first stage exhaust gas was assessed. The lobe mixer showed the best mixing quality and hence was expected to also be the best variant in terms of combustion. However atmospheric combustion tests showed lower emissions for the jet-in-cross-flow configuration. Comparing flame photos in the visible and ultraviolet (UV) range suggest that the flame might be lifted off for the lobe mixer, leading to insufficient time for carbon monoxide (CO) burnout. CFD analysis of turbulent flame speed, turbulence and strain rates support the hypotheses of lifted off flame. Overall the staged concept was found to show very promising results not only with natural gas but also with natural gas enriched with propane or hydrogen. The investigations showed that apart from having an efficient and compact mixing of the two stages it is also very important to design the flow field such that the second flame can be anchored properly in order to achieve compact flames with sufficient time for CO burnout.

Decarbonizing Power Generation Through the Use of Hydrogen As a Gas Turbine Fuel

2019 ◽  
Author(s):  
Michael Welch
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Carbon Content ◽  
Gas Turbine ◽  
Co2 Emissions ◽  
Gas Turbines ◽  
High Hydrogen ◽  
Wide Range ◽  
Zero Carbon ◽  
The Impact

Abstract The power generation industry has a major role to play in reducing global greenhouse gas emissions, and carbon dioxide (CO2) in particular. There are two ways to reduce CO2 emissions from power generation: improved conversion efficiency of fuel into electrical energy, and switching to lower carbon content fuels. Gas turbine generator sets, whether in open cycle, combined cycle or cogeneration configuration, offer some of the highest efficiencies possible across a wide range of power outputs. With natural gas, the fossil fuel with the lowest carbon content, as the primary fuel, they produce among the lowest CO2 emissions per kWh generated. It is possible though to decarbonize power generation further by using the fuel flexibility of the gas turbine to fully or partially displace natural gas used with hydrogen. As hydrogen is a zero carbon fuel, it offers the opportunity for gas turbines to produce zero carbon electricity. As an energy carrier, hydrogen is an ideal candidate for long-term or seasonal storage of renewable energy, while the gas turbine is an enabler for a zero carbon power generation economy. Hydrogen, while the most abundant element in the Universe, does not exist in its elemental state in nature, and producing hydrogen is an energy-intensive process. This paper looks at the different methods by which hydrogen can be produced, the impact on CO2 emissions from power generation by using pure hydrogen or hydrogen/natural gas blends, and how the economics of power generation using hydrogen compare with today’s state of the art technologies and carbon capture. This paper also addresses the issues surrounding the combustion of hydrogen in gas turbines, historical experience of gas turbines operating on high hydrogen fuels, and examines future developments to optimize combustion emissions.

NOx Correlation for an Industrial 10 MW Non-Premixed Gas Turbine Combustor for High Hydrogen Fuels

2016 ◽  
Author(s):  
Daniel Kroniger ◽  
Manfred Wirsum ◽  
Atsushi Horikawa ◽  
Kunio Okada ◽  
Masahide Kazari
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Gas Turbine ◽  
Hydrogen Content ◽  
Variable Pressure ◽  
Outlet Temperature ◽  
Nox Emissions ◽  
Gas Turbine Combustor ◽  
High Hydrogen ◽  
Operation Conditions

This paper describes a model to predict the nitric oxides (NOx) emissions for a dry non-premixed flame gas turbine combustor at full operation conditions. The NOx correlation considered the combustor pressure, the combustor outlet temperature and the fuel composition from natural gas (NG) to pure hydrogen (H2) fuel. The test data for parametrizing the model was acquired with a high pressure combustion test rig for industrial 10 MWth reverse-flow gas turbine combustors. The experimental results confirm the typical dependencies of NOx emissions. As expected, higher NOx emissions occur with increasing combustor pressure, combustor outlet temperature and hydrogen content of the fuel. The reference NOx model has been derived on the basis of physical approaches for the pressure and temperature effects. The substitution of natural gas with hydrogen is taken into account by a variable pressure exponent and a variable factor in the exponent of the exponential temperature correlation. As a result, the pressure exponent increases with increasing hydrogen. The temperature exponent factor decreases with increasing hydrogen. The model can describe the data set with limitations at high pressure and high hydrogen content fuel operation conditions.

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