Effect of pressure and fuel–air unmixedness on NOx emissions from industrial gas turbine burners

2007 ◽  
Vol 151 (1-2) ◽  
pp. 274-288 ◽  
Author(s):  
Fernando Biagioli ◽  
Felix Güthe
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.


Author(s):  
Alessandro Innocenti ◽  
Antonio Andreini ◽  
Andrea Giusti ◽  
Bruno Facchini ◽  
Matteo Cerutti ◽  
...  

In the present paper a numerical analysis of a low NOx partially premixed burner for industrial gas turbine applications is presented. The first part of the work is focused on the study of the premixing process inside the burner. Standard RANS CFD approach was used: k–ε turbulence model was modified and calibrated in order to find a configuration able to fit available experimental profiles of fuel/air concentration at the exit of the burner. The resulting profiles at different test points have been used to perform reactive simulations of an experimental test rig, where exhaust NOx emissions were measured. An assessment of the turbulent combustion model was carried out with a critical investigation of the expected turbulent combustion regimes in the system and taking into account the partially premixed nature of the flame due to the presence of diffusion type pilot flames. A reliable numerical setup was discovered by comparing predicted and measured NOx emissions at different operating conditions and at different split ratio between main and pilot fuel. In the investigated range, the influence of the premixer in the NOx formation rate was found to be marginal if compared with the pilot flame one. The calibrated numerical setup was then employed to explore possible modifications to fuel injection criteria and fuel split, with the aim of minimizing exhaust NOx emissions. This preliminary numerical screening of alternative fuel injection strategies allowed to define a set of advanced configurations to be investigated in future experimental tests.


Author(s):  
Urmila C. Reddy ◽  
Christine E. Blanchard ◽  
Barry C. Schlein

Pratt & Whitney has developed a novel water-injected Industrial Gas Turbine (IGT) combustor liner design that has demonstrated significant reduction in CO emissions when compared to typical film cooled combustor designs. The CO reduction demonstrated in a prototype test shows that the CO quenching due to cooler film temperatures near the liner wall is a significant source of CO emissions in a conventional water-injected combustor operating on natural gas fuel. This finding paved the way for a combustor design that reduces CO emissions while still maintaining low levels of NOx emissions. This design also has potential for lower NOx since the low CO emissions characteristic enables increased water-injection. This paper presents the emissions characteristics measured on prototype hardware and the design of the engine hardware for future validation. Significant reduction in gaseous emissions was demonstrated with the testing of a prototype at the United Technologies Research Center in East Hartford, CT. This reduction in emissions compared to the baseline film-cooled design for a given operating condition has many benefits to the customer, including reduced need for exhaust catalyst cleanup and extended operating times while still meeting site permits specified in CO tons per year. Other benefits may include the ability to guarantee lower NOx emissions through increased water injection for the current CO emissions output.


Author(s):  
Anders Hellberg ◽  
Georg Norden ◽  
Sergey Shukin

ALSTOM Power has launched the GT10C a 30 MW industrial gas turbine (see figure 1) upgraded from the 25 MW GT10B. The thermal efficiency of the new gas turbine is 37.3% (shaft) and 36% electrical at ISO inlet conditions with no losses. The new GT10C has a Dry Low Emission (DLE) combustor for both natural gas and diesel oil fuel; it has NOx emissions at 15 ppmv on gas and 42 ppmv on oil fuel (15% O2 dry). The first GT10C is now manufactured and assembled, and has been under testing since October 2001. For this purpose a new test rig has been built in Finspong, Sweden, in order to verify performance and reliability. GT10C will be available to the market mid-2002 and manufactured in parallel with GT10B. The general design is based on the GT10B and measures have been taken for maximum reliability and maintenance in order to keep operation costs to a minimum. Improvements for GT10C are mainly derived from GT10B or taken from ALSTOM Power GTX100 (43 MW gas turbine), as described herein.


Author(s):  
Narendra D. Joshi ◽  
Michael J. Epstein ◽  
Susan Durlak ◽  
Steven Marakovits ◽  
Paul E. Sabla

An experimental program was conducted to develop premixer concepts for use in GE’s aero-derivative Marine and Industrial gas turbine engines such as the LM 1600, 2500 and 6000. These engines operate typically at pressure ratios up to 30:1. Extensive tests in 1 and 2 cup test combustors were carried out to evaluate the Double Annular Counter-Rotating Swirler (DACRS) premixers at test conditions representative of the above mentioned engines. These tests also help establish combustor design parameters. Single digit NOx emissions were measured at engine operating conditions with the DACRS II and III premixers. Premixer interactions and their effects on Lean Blow Out were also studied.


2012 ◽  
Vol 36 (3) ◽  
pp. 251-257
Author(s):  
Dong-Hyun Nam ◽  
Hyun-Su Nam ◽  
Dong-Sik Han ◽  
Gyu-Bo Kim ◽  
Seung-Wan Cho ◽  
...  

Author(s):  
H. H.-W. Funke ◽  
S. Boerner ◽  
W. Krebs ◽  
E. Wolf

The use of renewable discontinuous energy sources, such as wind- or solar-energy, raises the question of ensuring the continuous demand for energy. For future energy storage scenarios, hydrogen combustion systems play an important role. This offers new opportunities for alternative combustion processes with regard to efficient, safe and low NOx combustion of hydrogen. In addition hydrogen combustion technology will be in need of gas turbine technology for future IGCC power plant concepts. Against the background of ensuring a secure and low NOx combustion of hydrogen, the micromix burning principle is developed since years and was first investigated for the use in aircraft jet engines to significantly reduce NOx-emissions. This combustion principle is based on cross-flow mixing of air and gaseous hydrogen and burns in multiple miniaturized diffusion type flames. The two advantages of this principle are the inherent safety against flash back and the low NOx-emissions due to a very short residence time of reactants in the flame region of the micro-flames. The paper presents an experimental in depth analysis of the combustion principle with regards to low NOx-emissions for higher energy densities. Therefore several geometric variations were investigated and the burning principle was scaled and tested for higher energy densities up to 15 MW/(m2bar). For the different geometries and energy densities, combustion stability, flame anchoring behavior and associated NOx-emissions are tested under preheated atmospheric conditions. The experimental results show the successful scaling of the micromix principle for high energy densities. The general mapping of the test burners demonstrates a wide operating range. Flow phenomena influencing the flame lifting and flame anchoring position with respect to the resulting NOx-emission are analyzed. The investigations highlight further potential for NOx-reduction in industrial gas turbine applications.


Author(s):  
Mahyar Akbari ◽  
Abdol Majid Khoshnood ◽  
Saied Irani

In this article, a novel approach for model-based sensor fault detection and estimation of gas turbine is presented. The proposed method includes driving a state-space model of gas turbine, designing a novel L1-norm Lyapunov-based observer, and a decision logic which is based on bank of observers. The novel observer is designed using multiple Lyapunov functions based on L1-norm, reducing the estimation noise while increasing the accuracy. The L1-norm observer is similar to sliding mode observer in switching time. The proposed observer also acts as a low-pass filter, subsequently reducing estimation chattering. Since a bank of observers is required in model-based sensor fault detection, a bank of L1-norm observers is designed in this article. Corresponding to the use of the bank of observers, a two-step fault detection decision logic is developed. Furthermore, the proposed state-space model is a hybrid data-driven model which is divided into two models for steady-state and transient conditions, according to the nature of the gas turbine. The model is developed by applying a subspace algorithm to the real field data of SGT-600 (an industrial gas turbine). The proposed model was validated by applying to two other similar gas turbines with different ambient and operational conditions. The results of the proposed approach implementation demonstrate precise gas turbine sensor fault detection and estimation.


Author(s):  
Edson Batista da Silva ◽  
Marcelo Assato ◽  
Rosiane Cristina de Lima

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.


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