The Reheat Concept: The Proven Pathway to Ultra-Low Emissions and High Efficiency and Flexibility

2007 ◽  
Author(s):  
Felix Gu¨the ◽  
Jaan Hellat ◽  
Peter Flohr
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Flame Propagation ◽  
High Efficiency ◽  
Flame Stabilization ◽  
Auto Ignition ◽  
Fuel Flexibility ◽  
Stage Combustion ◽  
Low Emission ◽  
Key Topics

Reheat combustion has proven now in over 80 units to be a robust, and highly flexible gas turbine concept for power generation. This paper covers three key topics to explain the intrinsic advantage of reheat combustion to achieve ultra-low emission levels. First, the fundamental kinetic and thermodynamic emission advantage of reheat combustion is discussed analyzing in detail the emission levels of the first and second combustor stages, optimal firing temperatures for minimal emission levels, as well as benchmarking against single-stage combustion concepts. Secondly, the generic operational and fuel flexibility of the reheat system is emphasized, which is based on the presence of two fundamentally different flame stabilization mechanisms, namely flame propagation in the first combustor stage and auto-ignition in the second combustor stage. Finally, the present fleet status is reported by highlighting the latest combustor hardware upgrade and its emission performance.

The Reheat Concept: The Proven Pathway to Ultralow Emissions and High Efficiency and Flexibility

2008 ◽  
Vol 131 (2) ◽  
Author(s):  
Felix Güthe ◽  
Jaan Hellat ◽  
Peter Flohr
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Flame Propagation ◽  
Kinetic Models ◽  
High Efficiency ◽  
Flame Stabilization ◽  
Emission Performance ◽  
Fuel Flexibility ◽  
Stage Combustion ◽  
Key Topics

Reheat combustion has been proven now in over 80units to be a robust and highly flexible gas turbine concept for power generation. This paper covers three key topics to explain the intrinsic advantage of reheat combustion to achieve ultralow emission levels. First, the fundamental kinetic and thermodynamic emission advantage of reheat combustion is discussed, analyzing in detail the emission levels of the first and second combustor stages, optimal firing temperatures for minimal emission levels, as well as benchmarking against single-stage combustion concepts. Second, the generic operational and fuel flexibility of the reheat system is emphasized, which is based on the presence of two fundamentally different flame stabilization mechanisms, namely, flame propagation in the first combustor stage and autoignition in the second combustor stage. This is shown using simple reasoning on generic kinetic models. Finally, the present fleet status is reported by highlighting the latest combustor hardware upgrade and its emission performance.

Design, Testing and Performance of the Recently Developed 37 MW Siemens SGT-750

2012 ◽  
Author(s):  
Anders Hellberg ◽  
Thomas Andersson ◽  
Anders Häggmark
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
High Performance ◽  
High Efficiency ◽  
Combined Cycle ◽  
Easy Access ◽  
Gas Generator ◽  
Gas Industry ◽  
Low Emission ◽  
And Performance

The 37MW Siemens SGT-750 is a high-performance twin-shaft gas turbine with a free power turbine. It can be employed both for power generation and as a mechanical drive. This gas turbine attains a simple cycle efficiency level of 40% and excellent performance in cogeneration as well as in combined cycle. Requirements from the oil & gas industry as well as industrial power generation have been heeded in the design. Since customer earnings are dependant upon turbine availability, uptime has been a major focus. Long service intervals, rapid gas generator exchange and easy access for borescope inspection all guarantee optimized availability. Maintenance work can be performed on site on the installed machine, alternatively the gas generator can be exchanged to minimize downtime. With this solution, maintenance downtime can be cut to a mere 17 days in 17 years. Furthermore, the hot-section blade temperatures can be monitored during operation as a “health check” to ensure availability. The SGT-750 is a “low-emission engine” equipped with a dry low emission (DLE) combustion system minimizing NOx and CO emissions. The high efficiency leads to a reduction of greenhouse gases with the further possibility to reduce the relative CO2-emissions in cogeneration or combined cycle. This paper will describe the development and testing of the SGT-750 gas turbine and the additional features which have been incorporated. A new development process has made it possible to increase uptime and serviceability; special attention has been brought to this aspect during the design phase, as will be highlighted in the paper.

Predicting Flameholding for Hydrogen and Natural Gas Flames at Gas Turbine Premixer Conditions

2016 ◽  
Vol 138 (12) ◽  
Author(s):  
Elliot Sullivan-Lewis ◽  
Vincent McDonell
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Experimental Studies ◽  
Temperature Variations ◽  
Auto Ignition ◽  
Chamber Temperature ◽  
Transient Events ◽  
Significant Effort

Lean-premixed gas turbines are now common devices for low emissions stationary power generation. By creating a homogeneous mixture of fuel and air upstream of the combustion chamber, temperature variations are reduced within the combustor, which reduces emissions of nitrogen oxides. However, by premixing fuel and air, a potentially flammable mixture is established in a part of the engine not designed to contain a flame. If the flame propagates upstream from the combustor (flashback), significant engine damage can result. While significant effort has been put into developing flashback resistant combustors, these combustors are only capable of preventing flashback during steady operation of the engine. Transient events (e.g., auto-ignition within the premixer and pressure spikes during ignition) can trigger flashback that cannot be prevented with even the best combustor design. In these cases, preventing engine damage requires designing premixers that will not allow a flame to be sustained. Experimental studies were conducted to determine under what conditions premixed flames of hydrogen and natural gas can be anchored in a simulated gas turbine premixer. Tests have been conducted at pressures up to 9 atm, temperatures up to 750 K, and freestream velocities between 20 and 100 m/s. Flames were anchored in the wakes of features typical of premixer passageways, including cylinders, steps, and airfoils. The results of this study have been used to develop an engineering tool that predicts under what conditions a flame will anchor, and can be used for development of flame anchoring resistant gas turbine premixers.

Three Spool High Efficiency Small Scale Gas Turbine Concept

2017 ◽  
Author(s):  
Matti Malkamäki ◽  
Ahti Jaatinen-Värri ◽  
Antti Uusitalo ◽  
Aki Grönman ◽  
Juha Honkatukia ◽  
...  
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Small Scale ◽  
Inlet Temperature ◽  
Substantial Impact ◽  
Electrical Efficiency ◽  
Partial Load ◽  
Reciprocating Engines

Decentralized electricity and heat production is a rising trend in small-scale industry. There is a tendency towards more distributed power generation. The decentralized power generation is also pushed forward by the policymakers. Reciprocating engines and gas turbines have an essential role in the global decentralized energy markets and improvements in their electrical efficiency have a substantial impact from the environmental and economic viewpoints. This paper introduces an intercooled and recuperated three stage, three-shaft gas turbine concept in 850 kW electric output range. The gas turbine is optimized for a realistic combination of the turbomachinery efficiencies, the turbine inlet temperature, the compressor specific speeds, the recuperation rate and the pressure ratio. The new gas turbine design is a natural development of the earlier two-spool gas turbine construction and it competes with the efficiencies achieved both with similar size reciprocating engines and large industrial gas turbines used in heat and power generation all over the world and manufactured in large production series. This paper presents a small-scale gas turbine process, which has a simulated electrical efficiency of 48% as well as thermal efficiency of 51% and can compete with reciprocating engines in terms of electrical efficiency at nominal and partial load conditions.

scholarly journals Biomass Gasification for Gas Turbine Based Power Generation

1997 ◽  
Author(s):  
Mark A. Paisley ◽  
Donald Anson
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
High Efficiency ◽  
Department Of Energy ◽  
Renewable Biomass ◽  
Process Economics ◽  
Gasification Process ◽  
The Us ◽  
Power Generation Systems

The Biomass Power Program of the US Department of Energy (DOE) has as a major goal the development of cost-competitive technologies for the production of power from renewable biomass crops. The gasification of biomass provides the potential to meet his goal by efficiently and economically producing a renewable source of a clean gaseous fuel suitable for use in high efficiency gas turbines. This paper discusses the development and first commercial demonstration of the Battelle high-throughput gasification process for power generation systems. Projected process economics are presented along with a description of current experimental operations coupling a gas turbine power generation system to the research scale gasifier and the process scaleup activities in Burlington, Vermont.

Alstom Gas Turbine Technology Overview: Status 2014

2015 ◽  
Author(s):  
Wolfgang Kappis ◽  
Stefan Florjancic ◽  
Uwe Ruedel
Keyword(s):  
Power Generation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
New Technologies ◽  
The United States ◽  
Heavy Duty ◽  
Fuel Flexibility ◽  
Market Requirements ◽  
Base Load ◽  
Very High

Market requirements for the heavy duty gas turbine power generation business have significantly changed over the last few years. With high gas prices in former times, all users have been mainly focusing on efficiency in addition to overall life cycle costs. Today individual countries see different requirements, which is easily explainable picking three typical trends. In the United States, with the exploitation of shale gas, gas prices are at a very low level. Hence, many gas turbines are used as base load engines, i.e. nearly constant loads for extended times. For these engines reliability is of main importance and efficiency somewhat less. In Japan gas prices are extremely high, and therefore the need for efficiency is significantly higher. Due to the challenge to partly replace nuclear plants, these engines as well are mainly intended for base load operation. In Europe, with the mid and long term carbon reduction strategy, heavy duty gas turbines is mainly used to compensate for intermittent renewable power generation. As a consequence, very high cyclic operation including fast and reliable start-up, very high loading gradients, including frequency response, and extended minimum and maximum operating ranges are required. Additionally, there are other features that are frequently requested. Fuel flexibility is a major demand, reaching from fuels of lower purity, i.e. with higher carbon (C2+), content up to possible combustion of gases generated by electrolysis (H2). Lifecycle optimization, as another important request, relies on new technologies for reconditioning, lifetime monitoring, and improved lifetime prediction methods. Out of Alstom’s recent research and development activities the following items are specifically addressed in this paper. Thermodynamic engine modelling and associated tasks are discussed, as well as the improvement and introduction of new operating concepts. Furthermore extended applications of design methodologies are shown. An additional focus is set ono improve emission behaviour understanding and increased fuel flexibility. Finally, some applications of the new technologies in Alstom products are given, indicating the focus on market requirements and customer care.

Study of Sequential Two-Stage Combustion in a Low-Emission Gas Turbine Combustion Chamber

2018 ◽  
Vol 65 (11) ◽  
pp. 806-817 ◽  
Author(s):  
L. A. Bulysova ◽  
A. L. Berne ◽  
V. D. Vasil’ev ◽  
M. N. Gutnik ◽  
M. M. Gutnik
Keyword(s):  
Combustion Chamber ◽  
Gas Turbine ◽  
Two Stage ◽  
Stage Combustion ◽  
Low Emission ◽  
Gas Turbine Combustion

Enhancing Gas Turbine Operation With Heavy Fuel Oil

2013 ◽  
Author(s):  
Vikram Muralidharan ◽  
Matthieu Vierling
Keyword(s):  
Power Generation ◽  
Natural Gas ◽  
Gas Turbine ◽  
Power Plants ◽  
High Efficiency ◽  
Combined Cycle ◽  
Fuel Oil ◽  
Residual Oil ◽  
Heavy Fuel Oil ◽  
Hydro Power

Power generation in south Asia has witnessed a steep fall due to the shortage of natural gas supplies for power plants and poor water storage in reservoirs for low hydro power generation. Due to the current economic scenario, there is worldwide pressure to secure and make more gas and oil available to support global power needs. With constrained fuel sources and increasing environmental focus, the quest for higher efficiency would be imminent. Natural gas combined cycle plants operate at a very high efficiency, increasing the demand for gas. At the same time, countries may continue to look for alternate fuels such as coal and liquid fuels, including crude and residual oil, to increase energy stability and security. In over the past few decades, the technology for refining crude oil has gone through a significant transformation. With the advanced refining process, there are additional lighter distillates produced from crude that could significantly change the quality of residual oil used for producing heavy fuel. Using poor quality residual fuel in a gas turbine to generate power could have many challenges with regards to availability and efficiency of a gas turbine. The fuel needs to be treated prior to combustion and needs a frequent turbine cleaning to recover the lost performance due to fouling. This paper will discuss GE’s recently developed gas turbine features, including automatic water wash, smart cooldown and model based control (MBC) firing temperature control. These features could significantly increase availability and improve the average performance of heavy fuel oil (HFO). The duration of the gas turbine offline water wash sequence and the rate of output degradation due to fouling can be considerably reduced.

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