scholarly journals Influence of high ethane content on natural gas ignition

2019 ◽  
Vol 16 (1) ◽  
pp. 36-42
Author(s):  
Hernando Alexander Yepes-Tumay ◽  
Arley Cardona-Vargas
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Fuel Mixture ◽  
Ignition Limit ◽  
Mode Analysis ◽  
Gas Combustion ◽  
Gas Ignition ◽  
Natural Gas Combustion

The effect of ethane on combustion and natural gas autoignition was studied in the present paper. Two fuel mixture of natural gas with high ethane content were considered, 75% CH4 – 25% C2H6 (mixture 1), and 50% CH4 – 50% C2H6 (mixture 2). Natural gas combustion incidence was analyzed through the calculation of energy properties and the ignition delay time numerical calculations along with an ignition mode analysis. Specifically, the strong ignition limit was calculated to determine the effect of ethane on natural gas autoignition. According to the results, ignition delay time decreases for both mixtures in comparison with pure methane. The strong ignition limit shifts to lower temperatures when ethane is present in natural gas chemical composition.  

scholarly journals Simulation of ignition delay time of compressed natural gas combustion

2015 ◽  
Vol 12 ◽  
pp. 3125-3140
Author(s):  
Yuswan Muharam ◽  
◽  
Mirza Mahendra ◽  
Dinda Gayatri ◽  
Sutrasno Kartohardjono ◽  
...  
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Compressed Natural Gas ◽  
Gas Combustion ◽  
Natural Gas Combustion

Ignition Studies of C1–C7 Natural Gas Blends at Gas-Turbine Relevant Conditions

2020 ◽  
Author(s):  
Amrit Bikram Sahu ◽  
A. Abd El-Sabor Mohamed ◽  
Snehasish Panigrahy ◽  
Gilles Bourque ◽  
Henry Curran
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Gas Mixtures ◽  
Auto Ignition ◽  
Wide Range ◽  
Detailed Kinetic Model ◽  
Sensitization Effect

Abstract New ignition delay time measurements of natural gas mixtures enriched with small amounts of n-hexane and n-heptane were performed in a rapid compression machine to interpret the sensitization effect of heavier hydrocarbons on auto-ignition at gas-turbine relevant conditions. The experimental data of natural gas mixtures containing alkanes from methane to n-heptane were carried out over a wide range of temperatures (840–1050 K), pressures (20–30 bar), and equivalence ratios (φ = 0.5 and 1.5). The experiments were complimented with numerical simulations using a detailed kinetic model developed to investigate the effect of n-hexane and n-heptane additions. Model predictions show that the addition of even small amounts (1–2%) of n-hexane and n-heptane can lead to increase in reactivity by ∼40–60 ms at compressed temperature (TC) = 700 K. The ignition delay time (IDT) of these mixtures decrease rapidly with an increase in concentration of up to 7.5% but becomes almost independent of the C6/C7 concentration beyond 10%. This sensitization effect of C6 and C7 is also found to be more pronounced in the temperature range 700–900 K compared to that at higher temperatures (> 900 K). The reason is attributed to the dependence of IDT primarily on H2O2(+M) ↔ 2ȮH(+M) at higher temperatures while the fuel dependent reactions such as H-atom abstraction, RȮ2 dissociation or Q.OOH + O2 reactions are less important compared to 700–900 K, where they are very important.

Numerical Study on the Effect of Real Syngas Compositions on Ignition Delay Times and Laminar Flame Speeds at Gas Turbine Conditions

2013 ◽  
Author(s):  
Olivier Mathieu ◽  
Eric L. Petersen ◽  
Alexander Heufer ◽  
Nicola Donohoe ◽  
Wayne Metcalfe ◽  
...  
Keyword(s):  
Ignition Delay ◽  
Delay Time ◽  
Gas Turbines ◽  
Ignition Delay Time ◽  
Laminar Flame ◽  
Numerical Study ◽  
Fuel Mixture ◽  
Flame Speed ◽  
Operating Conditions ◽  
Combustion Properties

Depending on the feedstock and the production method, the composition of syngas can include (in addition to H2 and CO) small hydrocarbons, diluents (CO2, water, and N2), and impurities (H2S, NH3, NOx, etc.). Despite this fact, most of the studies on syngas combustion do not include hydrocarbons or impurities and in some cases not even diluents in the fuel mixture composition. Hence, studies with realistic syngas composition are necessary to help designing gas turbines. The aim of this work was to investigate numerically the effect of the variation in the syngas composition on some fundamental combustion properties of premixed systems such as laminar flame speed and ignition delay time at realistic engine operating conditions. Several pressures, temperatures, and equivalence ratios were investigated. To perform this parametric study, a state-of-the-art C0-C5 detailed kinetics mechanism was used. Results of this study showed that the addition of hydrocarbons generally reduces the reactivity of the mixture (longer ignition delay time, slower flame speed) due to chemical kinetic effects. The amplitude of this effect is however dependent on the nature and concentration of the hydrocarbon as well as the initial condition (pressure, temperature, and equivalence ratio).

Numerical Studies of Glow Plug Shield on Natural Gas Ignition Characteristics in a CI Engine

2016 ◽  
Author(s):  
Kang Pan ◽  
James S. Wallace
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Numerical Study ◽  
Direct Injection ◽  
Fuel Mixture ◽  
Injection Angle ◽  
Glow Plug ◽  
Gas Ignition ◽  
Ignition And Combustion

This paper presents a numerical study on fuel injection, ignition and combustion in a direct-injection natural gas (DING) engine with ignition assisted by a shielded glow plug (GP). The shield geometry is investigated by employing different sizes of elliptical shield opening and changing the position of the shield opening. The results simulated by KIVA-3V indicated that fuel ignition and combustion is very sensitive to the relative angle between the fuel injection and the shield opening, and the use of an elliptical opening for the glow plug shield can reduce ignition delay by 0.1∼0.2ms for several specific combinations of the injection angle and shield opening size, compared to a circular shield opening. In addition, the numerical results also revealed that the natural gas ignition and flame propagation will be delayed by lowering a circular shield opening from the fuel jet center plane, due to the blocking effect of the shield to the fuel mixture, and hence it will reduce the DING performance by causing a longer ignition delay.

Experimental Study and Modeling of Autoignition of Natural Gas/Air-Mixtures Under Gas Turbine Relevant Conditions

2005 ◽  
Author(s):  
Andreas Koch ◽  
Clemens Naumann ◽  
Wolfgang Meier ◽  
Manfred Aigner
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Ignition Delay ◽  
Delay Time ◽  
High Speed ◽  
Ignition Delay Time ◽  
Evaluation Procedure ◽  
Ignition Process ◽  
Ignition Delay Times ◽  
Delay Times

The objective of this work was the improvement of methods for predicting autoignition in turbulent flows of different natural gas mixtures and air. Measurements were performed in a mixing duct where fuel was laterally injected into a turbulent flow of preheated and pressurized air. To study the influence of higher order hydrocarbons on autoignition, natural gas was mixed with propane up to 20% by volume at pressures up to 15 bar. During a measurement cycle, the air temperature was increased until autoignition occurred. The ignition process was observed by high-speed imaging of the flame chemiluminescence. In order to attribute a residence time (ignition delay time) to the locations where autoignition was detected the flow field and its turbulent fluctuations were simulated by numerical codes. These residence times were compared to calculated ignition delay times using detailed chemical simulations. The measurement system and data evaluation procedure are described and preliminary results are presented. An increase in pressure and in fraction of propane in the natural gas both reduced the ignition delay time. The measured ignition delay times were systematically longer than the predicted ones for temperatures above 950 K. The results are important for the design process of gas turbine combustors and the studies also demonstrate a procedure for the validation of design tools under relevant conditions.

Ignition Delay Time Correlation of C1 – C5 Natural Gas Blends for Intermediate and High Temperature Regime

2021 ◽  
Author(s):  
A. Abd El-Sabor Mohamed ◽  
Amrit Bikram Sahu ◽  
Snehasish Panigrahy ◽  
Gilles Bourque ◽  
Henry Curran
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Correlation Equation ◽  
Time Correlation ◽  
Reflected Shock ◽  
Global Correlation ◽  
Rate Form ◽  
Good Agreement

Abstract New ignition delay time (IDT) data for stoichiometric natural gas (NG) blends composed of C1 – C5 n-alkanes with methane as the major component were recorded using a high pressure shock tube (ST) at reflected shock pressures (p5) and temperatures (T5) in the range 20–30 bar and 1000–1500 K, respectively. The good agreement of the new IDT experimental data with literature data shows the reliability of the new data at the conditions investigated. Comparisons of simulations using the NUI Galway mechanism (NUIGMech1.0) show very good agreement with the new experimental results and with the existing data available in the literature. Empirical IDT correlation equations have been developed through multiple linear regression analyses for these C1 – C5 n-alkane/air mixtures using constant volume IDT simulations in the pressure range pC = 10–50 bar, at temperatures TC = 950–2000 K and in the equivalence ratio (φ) range 0.3–3.0. Moreover, a global correlation equation is developed using NUIGMech1.0, to predict the IDTs for these NG mixtures and other relevant data available in the literature. The correlation expression utilized in this study employs a traditional Arrhenius rate form including dependencies on the individual fuel fraction, TC, φ and pC.

scholarly journals PENGARUH VARIASI CAMPURAN OLI BEKAS DAN BIOSOLAR TERHADAP KARAKTERSITIK UJI PEMBAKARAN DROPLET

2017 ◽  
Vol 2 (2) ◽  
pp. 83-96
Author(s):  
Akhmad Syarief ◽  
Ahmad Ramadan ◽  
Misbachudin Misbachudin
Keyword(s):  
Burning Rate ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Fuel Mixture ◽  
Flash Point ◽  
Test Characteristics ◽  
Used Oil ◽  
Maximum Value ◽  
Mixed Oil

This study aims to determine the effect of mixed used oil and biodiesel mixture on droplet combustion test characteristics. . This research was conducted by dripping the fuel at the tip of the thermocouple to form a droplet with a volume of 0.1 mm, then bringing the heater to the droplet to form a fire. This study aims to determine the influence of mixed oil and biosolar of flash point value, ignition delay time, burning rate and maximum fire height. This research used variation of used oil mixture 10%, 20%, 30%, 40% and 50%. The results show that flash point value increases with increasing percentage of used oil, which is influenced by the viscosity, density, and volatility of each variation of fuel mixture. The value of the ignition delay time increases with increasing percentage of used oil, which is influenced by the viscosity, density and volatility of each variation of fuel mixture. The burning rate value decreases with the increase of the used oil mixture, which is influenced by the viscosity, density, and volatility of each variation of fuel mixture. The maximum value of fire that can be achieved decreases, along with the increase of variation of used oil mixture and is influenced by viscosity, density and volatility value and each variation of fuel mixture.

Parametric study of pilot-ignited direct-injection natural gas combustion in an optically accessible heavy-duty engine

2019 ◽  
Vol 21 (3) ◽  
pp. 497-513 ◽  
Author(s):  
Jeremy Rochussen ◽  
Gordon McTaggart-Cowan ◽  
Patrick Kirchen
Keyword(s):  
Natural Gas ◽  
Heat Release ◽  
Internal Combustion Engines ◽  
Direct Injection ◽  
Injection Pressure ◽  
Gas Combustion ◽  
Gas Ignition ◽  
Partially Premixed ◽  
Natural Gas Combustion ◽  
Combustion Processes

Natural gas is an attractive fuel for internal combustion engines in light of its potential for reduced greenhouse gas and particulate emissions, and significant reserves. To facilitate natural gas use in compression ignition engines, pilot-ignited direct-injection natural gas combustion uses a small pilot injection of diesel to ignite a more significant direct injection of natural gas. Compared to modern diesel combustion, this strategy is a promising technology for the reduction of CO2 emissions while retaining diesel-like efficiency without a significant CH4 emission penalty. To further develop this technology, investigation of in-cylinder combustion processes is needed to identify the primary fuel conversion processes. The objective of this work was to provide a framework of conceptual understanding by identifying key processes in a typical pilot-ignited direct-injection natural gas combustion event and characterizing their sensitivity to fuel injection parameters. A parametric sweep of injection pressure, natural gas injection duration, and relative timing of the diesel pilot and natural gas injections was performed in an optically accessible 2 L single-cylinder engine. Combined heat release rate and OH*-chemiluminescence reaction zone analysis was used to demarcate the transition from ignition reactions to primary natural gas heat release. Five distinct combustion processes were identified: (1) pilot auto-ignition; (2) natural gas ignition; (3) rapid, distributed partially premixed natural gas combustion; (4) non-premixed combustion; and (5) late-cycle oxidation. While natural gas ignition was found to be insensitive to injection pressure, it was strongly affected by the time between pilot and natural gas injections. Reducing the relative injection timing from +8° to −6° resulted in the primary natural gas heat release transitioning from non-premixed, to distributed partially premixed, to stratified premixed flame propagation as a result of increasing natural gas premixing. The presented measurements and analysis serve to refine an initial conceptual model of the combustion process and lay the groundwork for future, more focused studies of pilot-ignited, direct-injection natural gas combustion.

Performance Predictions of a Hydrogen-Enhanced Natural Gas HCCI Engine

2005 ◽  
Author(s):  
K. Raitanapaibule ◽  
K. Aung
Keyword(s):  
Natural Gas ◽  
Ignition Delay ◽  
Delay Time ◽  
Ignition Delay Time ◽  
Ignition Time ◽  
Peak Temperature ◽  
Inlet Temperature ◽  
Hcci Combustion ◽  
Performance Predictions ◽  
Temperature And Pressure

The characteristics of HCCI engines were numerically investigated by CHEMKIN software, CHEMKIN 4.0. Cylinder temperature and pressure, ignition delay time, peak temperature and pressure, indicated work, indicated power and IMEP were performed for the analysis the HCCI combustion of Methane and Hydrogen. The natural gas can be represented as the Methane (CH4), which is the main ingredient. The simulation evaluations were done by increasing the initial concentrations of H2, changing the initial temperature (inlet temperature), or varying the equivalence ratio. The numerical simulations were accomplished using CHEMKIN Suite from Reaction Design and the results are focused on ignition time, peak temperature, and indicated power. The effect of hydrogen addition to methane increases peak temperature and pressure, decreases ignition delay time, and increases indicated power.

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