Flammability Limits of Low BTU Gases: Computations in a Perfectly Stirred Reactor and Experiments

2001 ◽  
Author(s):  
Fredrik Hermann ◽  
Thomas Ruck ◽  
Jens Klingmann ◽  
Fabian Mauss
Keyword(s):  
Residence Time ◽  
Gas Turbines ◽  
Thermodynamic Quantities ◽  
Flammability Limits ◽  
Gaseous Fuels ◽  
Stirred Reactor ◽  
Stability Limits ◽  
Extinction Point ◽  
Lower Heating ◽  
Made In

The demand for gas turbines suitable for Low Btu gases is increasing worldwide. This paper presents a theoretical and experimental investigation of the flammability limits of Low Btu gases for gas turbine applications. Most modern gas turbines utilize premixed combustion, making it important to know at which fuel-air ratio the flame extinguishes. The flammability limit for a gaseous fuel is a property, which is coupled to both thermodynamic quantities and the shape of the combustion chamber. Consequently, this property is characteristic for each combustor and for each fuel. The experiments were made in an atmospheric pressure premixed combustor at Alstom Power Technology Ltd. Switzerland, adapted for Low Btu gaseous fuels. Five different residual gases from chemical factories were investigated. The gases consisted of methane, carbon monoxide, hydrogen and nitrogen, with lower heating values about 2-3.5 MJ/kg for all examined gases (Table 1). A steady state Perfectly Stirred Reactor (PSR) was used as a model for the primary combustion zone. The reactions were modeled by a detailed mechanism for methane with 61 species and 667 reactions, developed by Warnatz [1]. The PSR calculations were done by decreasing the residence time until the combustion in the PSR extinguished. These calculations were repeated for different equivalence ratios to obtain the relation between the residence time and the limit of flammability. The calculations showed a relationship between the residence time in the PSR and the extinction point. It was found that the computed values of the flammability limits, or more correctly called stability limits, qualitatively follow the experimental results. However, since the computational results are strongly dependent on the residence time, a comparison with the experiments must include the residence time of the real burner, which is difficult to define.

Comparison Between Two-Shaft Simple and Single-Shaft Recuperated Brayton Cycles Using Different Types of Gaseous Fuels

2010 ◽  
Author(s):  
A. K. Malkogianni ◽  
A. Tourlidakis ◽  
A. L. Polyzakis
Keyword(s):  
Natural Gas ◽  
Gas Turbines ◽  
Alternative Fuels ◽  
High Efficiency ◽  
Heating Value ◽  
Gaseous Fuels ◽  
Oil And Natural Gas ◽  
Parametric Studies ◽  
The Impact ◽  
Lower Heating

Geopolitical issues give rise to problems in the smooth and continuous flow of oil and natural gas from the production countries to the consumers’ development countries. In addition, severe environmental issues such as greenhouse gas emissions, eventually guide the consumers to fuels more suitable to the present situation. Alternative fuels such as biogas and coal gas have recently become more attractive because of their benefits, especially for electricity generation. On the other hand, the use of relatively low heating value fuels has a significant effect to the performance parameters of gas turbines. In this paper, the impact of using four fuels with different heating value in the gas turbine performance is simulated. Based on the high efficiency and commercialization criteria, two types of engines are chosen to be simulated: two-shaft simple and single-shaft recuperated cycle gas turbines. The heating values of the four gases investigated, correspond to natural gas and to a series of three gases with gradually lower heating values than that of natural gas. The main conclusions drawn from this design point (DP) and off-design (OD) analysis is that, for a given TET, efficiency increases for both engines when gases with low heating value are used. On the contrary, when power output is kept constant, the use of gases with low heating value will result in a decrease of thermal efficiency. A number of parametric studies are carried out and the effect of operating parameters on performance is assessed. The analysis is performed with customized software, which has been developed for this purpose.

Modeling Static Instabilities of Biogas Flames in a Stirred-Reactor Using Detailed Chemical Kinetics Simulations

2013 ◽  
Author(s):  
Christopher D. Bolin ◽  
Abraham Engeda
Keyword(s):  
Gas Turbines ◽  
Static Stability ◽  
Gas Turbine Combustor ◽  
Detailed Chemical Kinetics ◽  
Reduced Mechanism ◽  
Stirred Reactor ◽  
Primary Zone ◽  
Stability Limits ◽  
Different Sources ◽  
Detailed Chemical

Kinetic modeling of lean static stability limits of the combustion of biogas type fuels in a model of an ideal primary zone of a gas turbine combustor is presented here. In this study, CH4 is diluted with CO2 to simulate a range of gases representative of the products of anaerobic digestion of organic materials from different sources (e.g., landfill and animal waste digester). Fuels of this type are of interest for use in small gas turbines used in distributed generation applications. Predictions made by two detailed mechanisms (GRI-Mech 3.0 and San Diego) and one reduced mechanism (GRI-Mech 1.2, reduced) are employed to investigate the underlying kinetics near lean extinction. Approximate correlations to lean extinction are extracted from these results and compared to those of other fuels.

Establishing Operating Limits in a Commercial Lean Premixed Combustor Operating on Synthesis Gas Pertaining to Flashback and Blowout

2012 ◽  
Author(s):  
David Page ◽  
Brendan Shaffer ◽  
Vincent McDonell
Keyword(s):  
Natural Gas ◽  
Synthesis Gas ◽  
Gas Turbines ◽  
Key Factors ◽  
High Hydrogen ◽  
Lean Blowout ◽  
Stirred Reactor ◽  
Operating Limits ◽  
The Stability ◽  
Stability Limits

Operability issues such as flashback and lean blow out are phenomena that must be addressed for successful commercial operation of stationary gas turbines. The present work focuses on flashback and lean blow out of premixed jet flames in a combustor from a commercially available gas turbine operating on synthesis gas compositions. The issue of flashback is exacerbated when operating on fuels with high hydrogen content due to the increased reactivity of hydrogen, thus increasing the propensity for flashback. Operating margins for mixtures of natural gas and carbon monoxide in hydrogen are reported. The results interestingly demonstrate reduced stability for mixtures of H2/NG than for H2/CO. Increasing H2 percentage from 0% to 100% reduced blowout equivalence ratios from Φ = 0.63 to Φ = 0.29 for H2/NG and Φ = 0.42 to Φ = 0.29 for H2/CO. In addition, results obtained for inlet temperatures of 300K and 623K are compared and show an upward shift of the stability limits for higher preheats. Modeling of the experimental data using a perfectly stirred reactor predicts the effect of the addition of H2 to natural gas on the blowout limits. With regards to flashback some key factors that dominate the characteristics are identified and attempts to correlate data are carried out. The results show that lean blowout and flashback occur at the same AFT, regardless of preheat temperatures. AFT at flashback and lean blowout are compared to a more fundamental burner [1] with results indicating reasonable scalability.

Bench Scale Testing of Low-NOx LBG Combustors

1982 ◽  
Vol 104 (1) ◽  
pp. 120-128 ◽  
Author(s):  
W. D. Clark ◽  
B. A. Folsom ◽  
W. R. Seeker ◽  
C. W. Courtney
Keyword(s):  
Gas Turbine ◽  
Residence Time ◽  
Attractive Alternative ◽  
Nox Emissions ◽  
Catalytic Reactor ◽  
Power Cycle ◽  
Bench Scale ◽  
Gasification Process ◽  
Stirred Reactor ◽  
Catalytic Reformer

The high efficiencies obtained in a combined gas-turbine/steam-turbine power cycle burning low Btu gas (LBG) make it a potentially attractive alternative to the high sulfur emitting direct coal-fired steam cycle. In the gasification process, much of the bound nitrogen in coal is converted to ammonia in the LBG. This ammonia is largely converted to nitrogen oxides (NOx) in conventional combustors. This paper examines the pressurized bench scale performance of reactors previously demonstrated to produce low NOx emissions in atmospheric laboratory scale experiments. LBG was synthesized in a catalytic reformer and fired in three reactors: a catalytic reactor, a diffusion flame, and a stirred reactor. Effects of scale, pressure, stoichiometry, residence time, and preheat were examined. Lowest NOx emissions were produced in a rich/lean series staged catalytic reactor.

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):  
Gas Turbine ◽  
Distribution System ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Liquid Fuels ◽  
Dual Fuel ◽  
Gaseous Fuels ◽  
Supply And Distribution ◽  
Industrial Gas Turbines

Abstract Industrial gas turbines like the MGT6000 are often operated as power supply or as mechanical drives. 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 capable of ultra-low NOx emissions for gaseous fuels. This system has been further developed to provide dry dual fuel capability. 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. The pilot stage is continuously operated, whereas the bulk of the liquid fuel is injected through the premixed combustor stage. The premixed stage comprises a set of four decentralized nozzles based on fluidic oscillator atomizers, wherein atomization of the liquid fuel is achieved through self-induced oscillations. We present results illustrating the spray, hydrodynamic, and emission performance of the injectors. Extensive testing of the burner at atmospheric and full load high-pressure conditions has been performed, before verification within full engine tests. We show the design of the fuel supply and distribution system. Finally, we discuss the integration of the dual fuel system into the standard gas turbine package of the MGT6000.

scholarly journals Breaking the Barriers

2012 ◽  
Vol 134 (05) ◽  
pp. 32-37
Author(s):  
Lee S. Langston
Keyword(s):  
Fluid Mechanics ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Solid Mechanics ◽  
Commercial Aircraft ◽  
Commercial Aviation ◽  
New Developments ◽  
Exhaust Heat ◽  
Turbine Component ◽  
Made In

This article explores the new developments in the field of gas turbines and the recent progress that has been made in the industry. The gas turbine industry has had its ups and downs over the past 20 years, but the production of engines for commercial aircraft has become the source for most of its growth of late. Pratt & Whitney’s recent introduction of its new geared turbofan engine is an example of the primacy of engine technology in aviation. Many advances in commercial aviation gas turbine technology are first developed under military contracts, since jet fighters push their engines to the limit. Distributed generation and cogeneration, where the exhaust heat is used directly, are other frontiers for gas turbines. Work in fluid mechanics, heat transfer, and solid mechanics has led to continued advances in compressor and turbine component performance and life. In addition, gas turbine combustion is constantly being improved through chemical and fluid mechanics research.

scholarly journals Pengaruh Hidroksi Propil Metil Selulosa Sebagai Polimer Mucoadhesiv Terhadap Sifat Fisik Patch Minyak Cengkeh (Syzygium aromaticum. L)

2019 ◽  
Vol 6 (2) ◽  
pp. 103
Author(s):  
Pramulani Mulya Lestari ◽  
Kori Yati
Keyword(s):  
Residence Time ◽  
Polymer Concentration ◽  
Methyl Cellulose ◽  
Average Weight ◽  
Syzygium Aromaticum ◽  
Clove Oil ◽  
Key Word ◽  
Folding Endurance ◽  
Active Substances ◽  
Made In

ABSTRAK Minyak cengkeh (Syzygium aromaticum) secara tradisional digunakan untuk untuk mengatasi masalah gigi dan mulut, pengembangan bentuk sediaan patch untuk mempertahankan zat aktif pada area gingival dan mencegah wash-out oleh saliva, polimer HPMC yang bersifat mukoadhesif mampu mampu berikatan pada mukosa mulu. Tujuan dari penelitian ini adalah untuk mengetahui pengaruh penggunaan HPMC (hidroksi Propil Metil Selulosa)sebagai polimer mucoadhesiv terhadap karakteristik fisik sediaan patch minyak cengkeh. Minyak cengkeh dibuat dalam bentuk sediaan emulsi m/a, yang selanjutnya ditambahkan dalam basis gel dengan variasi polimer HPMC yaitu 1 %; 1,5 %; 2 % dan dikeringkan. Patch yang terbentuk dievaluasi bobot rata – rata, pH, ketebalan,  folding endurance, waktu tinggal dan swelling indeks. Hasil penelitian ini menunjukkan ketiga formula memiliki  bobot rata- rata 21,33 – 29,63 mg  pada ukuran 2 x 1 cm, pH 6, mampu bertahan lebih dari 250 lipatan, dan waktu tinggal 24 – 25 menit. Berdasarkan pada penelitian ini dapat disimpulkan konsentrasi HPMC mempengaruhi sifat fisik patch yang dihasilkan. Semakin tinggi konsentrasi HPMC maka bobot, ketebalan, waktu tinggal dan indeks mengembang patch juga semakin meningkat, sedangkan tidak terjadi perubahan pH dan kekuatan lipat pada variasi konsentrasi polimer 1 % - 2 % yang digunakan. Key word : HPMC, minyak cengkeh, patch  ABSTRACT Clove oil (Syzygium aromaticum) has traditionally been used to overcome dental and oral problems, the development of patch dosage forms to maintain active substances in the gingival area and prevent wash-out by saliva, the mucoadhesive adhesive HPMC polymer capable of binding to the oral mucosa. The purpose of this study was to determine the effect of using HPMC (Hydroxy Propyl Methyl Cellulose) as a mucoadhesiv polymer on the physical characteristics of clove oil patch preparations. Clove oil is made in the form of m / a emulsion, which is then added to a gel base with a variation of polymer HPMC that is 1%; 1.5%; 2% and dried. The patches formed are evaluated for average weight, pH, thickness, folding endurance, residence time and index swelling. The results of this study indicate that the three formulas have an average weight of 21.33 - 29.63 mg at a size of 2 x 1 cm, pH 6, able to withstand more than 250 folds, and a residence time of 24-25 minutes. Based on this study it can be concluded the concentration of HPMC affects the physical properties of the resulting patch. The higher the concentration of HPMC, the weight, thickness, residence time and index of the swell patch also increased, while there was no change in pH and folding strength at variations in the polymer concentration of 1% - 2% used. Key word: HPMC, clove oil, patch

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