Comparison of Emissions from Natural Gas and Gasoline Fuelled Engines - Total Hydrocarbon and Methane Emissions and Exhaust Gas Recirculation Effects

1997 ◽  
Author(s):  
R. R. Raine ◽  
G. Zhang ◽  
A. Pflug
Keyword(s):  
Natural Gas ◽  
Exhaust Gas Recirculation ◽  
Methane Emissions ◽  
Exhaust Gas ◽  
Total Hydrocarbon ◽  
Gas Recirculation

Homogeneous Ignition Delay, Flame Propagation Rate and End-Gas Autoignition Fraction Measurements of Natural Gas and Exhaust Gas Recirculation Blends in a Rapid Compression Machine

2020 ◽  
Author(s):  
Jeffrey Mohr ◽  
Bret Windom ◽  
Daniel B. Olsen ◽  
Anthony J. Marchese
Keyword(s):  
Natural Gas ◽  
Flame Propagation ◽  
Ignition Delay ◽  
Exhaust Gas Recirculation ◽  
Propagation Rate ◽  
Delay Period ◽  
Exhaust Gas ◽  
Rapid Compression Machine ◽  
Gas Recirculation ◽  
Ignition Delay Period

Abstract To evaluate the effect of exhaust gas recirculation (EGR) and variable fuel reactivity on knock and misfire in spark ignited national gas engines, experiments were conducted in a rapid compression machine to measure homogeneous ignition delay, flame propagation rate, and end-gas autoignition fraction for stoichiometric natural gas/oxidizer/EGR blends. Natural gas with a range of chemical reactivity was simulated using mixtures of CH4, C2H6, and C3H8. Reactive exhaust gas recirculation (R-EGR) gases were simulated with mixtures of Ar, CO2, CO, and NO and non-reactive exhaust gas recirculation gases (NR-EGR) were simulated with mixtures of AR and CO2. Homogeneous ignition delay period, flame propagation rate and end-gas autoignition fraction were measured at compressed pressures and temperatures of 30.2 to 34.0 bar and 667 to 980 K, respectively. Flame propagation rate decreased with both R-EGR and NR-EGR substitution. The substitution of R-EGR increased the end-gas autoignition fraction, whereas NR-EGR substitution decreased the end-gas autoignition fraction. The results indicate that the presence of the reactive species NO in the R-EGR has a strong impact on end-gas autoignition fraction. An 82-species reduced chemical kinetic mechanism was also developed that reproduces measured homogeneous ignition delay period with a total average relative error of 11.0%.

Hydrogen enrichment: A way to maintain combustion stability in a natural gas fuelled engine with exhaust gas recirculation, the potential of fuel reforming

2001 ◽  
Vol 215 (3) ◽  
pp. 405-418 ◽  
Author(s):  
S. Allenby ◽  
W-C. Chang ◽  
A. Megaritis ◽  
M. L. Wyszyński
Keyword(s):  
Natural Gas ◽  
Exhaust Gas Recirculation ◽  
Combustion Stability ◽  
Exhaust Gas ◽  
Fuel Reforming ◽  
Rapid Reduction ◽  
Indicated Mean Effective Pressure ◽  
Hydrogen Enrichment ◽  
Gas Recirculation ◽  
Operating Points

An experimental study was carried out to evaluate the potential of hydrogen enrichment to increase the tolerance of a stoichiometrically fuelled natural gas engine to high levels of dilution by exhaust gas recirculation (EGR). This provides significant gains in terms of exhaust emissions without the rapid reduction in combustion stability typically seen when applying EGR to a methane-fuelled engine. Presented results give the envelope of benefits from hydrogen enrichment. In parallel, the performance of a catalytic exhaust gas reforming reactor was investigated in order that it could be used as an onboard source of hydrogen-rich EGR. It was shown that sufficient hydrogen was generated with currently available prototype catalysts to allow the engine, at the operating points considered, to tolerate up to 25 per cent EGR, while maintaining a coefficient of variability of indicated mean effective pressure below 5 per cent. This level of EGR gives a reduction in NO emissions greater than 80 per cent in all test cases.

scholarly journals Calculation studies of the influence of exhaust gas recirculation on the characteristics of the natural gas-fueled diesel engine

2021 ◽  
Vol 2061 (1) ◽  
pp. 012065
Author(s):  
I I Libkind ◽  
A V Gonturev
Keyword(s):  
Diesel Engine ◽  
Natural Gas ◽  
Fuel Mixture ◽  
Exhaust Gas Recirculation ◽  
Intake Manifold ◽  
Nox Emissions ◽  
Exhaust Gas ◽  
Diesel Cycle ◽  
Gas Fueled ◽  
Gas Recirculation

Abstract When converting diesel engines to run on natural gas on the gas-diesel cycle, additional problems arise associated with the high thermal stress of the exhaust valves and valve seats at high loads and engine speeds. There is also an increase in NOx emissions due to higher combustion temperatures of natural gas. One of the ways to improve the economic and environmental performance of engines operating on a gas-diesel cycle with a lean air-fuel mixture is to optimize the combustion of the air-fuel mixture by using an exhaust gas recirculation system (EGR). The principle of operation of this system is as follows: exhaust gas entering the intake manifold and further into the combustion chamber reduces the oxygen concentration in the air-fuel mixture, which leads to a dilution effect and, accordingly, to a decrease in combustion temperature and a decrease in NOx content. In order to study the influence of EGR on the dual-fuel gas and diesel engine parameters in the AVL Boost software package, a computer model of the existing 6ChN13/15 engine was developed. A low-pressure EGR system with an exhaust gas cooler was simulated on this engine. Values of NOx emissions, brake specific fuel consumption (BSFC) and brake efficiency have been obtained at different recirculation rate by calculation method. These values allow to estimate the feasibility of using a cooled EGR in a natural gas-fueled diesel engine.

Process Analysis of Selective Exhaust Gas Recirculation for CO2 Capture in Natural Gas Combined Cycle Power Plants Using Amines

2017 ◽  
Author(s):  
Maria Elena Diego ◽  
Jean-Michel Bellas ◽  
Mohamed Pourkashanian
Keyword(s):  
Natural Gas ◽  
Co2 Capture ◽  
Flue Gas ◽  
Power Plants ◽  
Exhaust Gas Recirculation ◽  
Combined Cycle ◽  
Exhaust Gas ◽  
Natural Gas Combined Cycle ◽  
The Cost ◽  
Gas Recirculation

Post-combustion CO2 capture from natural gas combined cycle (NGCC) power plants is challenging due to the large flow of flue gas with low CO2 content (∼3–4%vol.) that needs to be processed in the capture stage. A number of alternatives have been proposed to solve this issue and reduce the costs of the associated CO2 capture plant. This work focuses on the selective exhaust gas recirculation (S-EGR) configuration, which uses a membrane to selectively recirculate CO2 back to the inlet of the compressor of the turbine, thereby greatly increasing the CO2 content of the flue gas sent to the capture system. For this purpose, a parallel S-EGR NGCC system (53% S-EGR ratio) coupled to an amine capture plant using MEA 30%wt. was simulated using gCCS (gPROMS). It was benchmarked against an unabated NGCC system, a conventional NGCC coupled with an amine capture plant (NGCC+CCS), and an EGR NGCC power plant (39% EGR ratio) using amine scrubbing as the downstream capture technology. The results obtained indicate that the net power efficiency of the parallel S-EGR system can be up to 49.3% depending on the specific consumption of the auxiliary S-EGR systems, compared to the 49.0% and 49.8% values obtained for the NGCC+CCS and EGR systems, respectively. A preliminary economic study was also carried out to quantify the potential of the parallel S-EGR configuration. This high-level analysis shows that the cost of electricity for the parallel S-EGR system varies from 82.1–90.0 $/MWhe for the scenarios considered, with the cost of CO2 avoided being in the range of 79.7–105.1 $/tonne CO2. The results obtained indicate that there are potential advantages of the parallel S-EGR system in comparison to the NGCC+CCS configuration in some scenarios. However, further benefits with respect to the EGR configuration will depend on future advancements and cost reductions achieved on membrane-based systems.

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