Modeling NOx Emissions from Lean-Burn Natural Gas Engines

1998 ◽  
Author(s):  
Lee G. Dodge ◽  
John T. Kubesh ◽  
David W. Naegeli ◽  
Patrick F. Campbell
Keyword(s):  
Natural Gas ◽  
Nox Emissions ◽  
Lean Burn ◽  
Natural Gas Engines

Experience With Gas Engines Optimized for H2-Rich Fuels

2003 ◽  
Author(s):  
G. R. Herdin ◽  
F. Gruber ◽  
D. Plohberger ◽  
M. Wagner
Keyword(s):  
Natural Gas ◽  
Fuel Efficiency ◽  
Electrical Power ◽  
Nox Emissions ◽  
Engine Emissions ◽  
Lean Burn ◽  
Good Efficiency ◽  
Gas Engine ◽  
Natural Gas Engines ◽  
Fuel Technology

The gas engine is a very efficient possibility of a technological approach for the conversion of chemically bound energy into mechanical or electrical power. Degrees of efficiency achieved thus far through the electrification of natural gas amount to up to 45% depending on the engine size and further potentials are already being opened up. Gas engines therefore do not need to fear a comparison with diesel engines in terms of efficiency. The modern gas engines have considerable advantages regarding emissions. The state of the art for the NOx emissions of natural gas engines can presently be given as 0.7 g/kWh (diesel 5 g NOx/kWh) with practically particle-free combustion. As a result of these features the gas engine is especially suitable for the very efficient process of cogeneration of heat and power, through which total degrees of fuel efficiency of about 90% can be attained. As such, the gas engine is even superior to all previously introduced types of fuel cells. The utilization of H2-rich gases as fuel can be seen as a new field of application of gas engines. Jenbacher AG already has many years of experience in the field of “H2-rich fuels” with optimization of combustion control and mixture formation. The H2 content extend from 100% to very low caloric values of gases in the range of 1.67 MJ/Nm3. The gases to be utilized by the gas engines come primarily from thermal pyrolysis processes of biomass or RDF fuels. A very good efficiency behavior with uncommonly low NOx emissions can be determined as the common result of all gas engine sizes. In the case of the high NH3 content of e.g. wood gas, despite the extreme lean-burn operation through the primary formation of NOx from the fuel, no NOx minimum can be attained. For the future, making the step into H2-rich fuel technology particularly regarding emissions means a big step towards the low NOx concepts and thus the further reduction of engine emissions.

Numerical Simulations of Mixture Formation in Combustion Chambers of Lean-Burn Natural Gas Engines Incorporating a Sub-Chamber

2017 ◽  
Author(s):  
Yuzuru Nada ◽  
So Morimoto ◽  
Yoshiyuki Kidoguchi ◽  
Ryu Kaya ◽  
Hideaki Nakano ◽  
...  
Keyword(s):  
Natural Gas ◽  
Numerical Simulations ◽  
Combustion Chambers ◽  
Mixture Formation ◽  
Lean Burn ◽  
Natural Gas Engines

scholarly journals Emission of Toxic HCN During NO x Removal by Ammonia SCR in the Exhaust of Lean‐Burn Natural Gas Engines

2020 ◽  
Vol 59 (34) ◽  
pp. 14423-14428 ◽  
Author(s):  
Deniz Zengel ◽  
Pirmin Koch ◽  
Bentolhoda Torkashvand ◽  
Jan‐Dierk Grunwaldt ◽  
Maria Casapu ◽  
...  
Keyword(s):  
Natural Gas ◽  
Lean Burn ◽  
Natural Gas Engines

Experimental study of combustion strategy for jet ignition on a natural gas engine

2020 ◽  
pp. 146808742097775
Author(s):  
Ziqing Zhao ◽  
Zhi Wang ◽  
Yunliang Qi ◽  
Kaiyuan Cai ◽  
Fubai Li
Keyword(s):  
Experimental Study ◽  
Natural Gas ◽  
Efficient Points ◽  
Lean Burn ◽  
Gas Engine ◽  
Absolute Value ◽  
Natural Gas Engines ◽  
Natural Gas Engine ◽  
Excess Air ◽  
Lean Limit

To explore a suitable combustion strategy for natural gas engines using jet ignition, lean burn with air dilution, stoichiometric burn with EGR dilution and lean burn with EGR dilution were investigated in a single-cylinder natural gas engine, and the performances of two kinds of jet ignition technology, passive jet ignition (PJI) and active jet ignition (AJI), were compared. In the study of lean burn with air dilution strategy, the results showed that AJI could extend the lean limit of excess air ratio (λ) to 2.1, which was significantly higher than PJI’s 1.6. In addition, the highest indicated thermal efficiency (ITE) of AJI was shown 2% (in absolute value) more than that of PJI. Although a decrease of NOx emission was observed with increasing λ in the air dilution strategy, THC and CO emissions increased. Stoichiometric burn with EGR was proved to be less effective, which can only be applied in a limited operation range and had less flexibility. However, in contrast to the strategy of stoichiometric burn with EGR, the strategy of lean burn with EGR showed a much better applicability, and the highest ITE could achieve 45%, which was even higher than that of lean burn with air dilution. Compared with the most efficient points of lean burn with pure air dilution, the lean burn with EGR dilution could reduce 78% THC under IMEP = 1.2 MPa and 12% CO under IMEP = 0.4 MPa. From an overall view of the combustion and emission performances under both low and high loads, the optimum λ would be from 1.4 to 1.6 for the strategy of lean burn with EGR dilution.

A Literature Review of NOx Formation Kinetics and a Prediction Method for Lean-Burn, Two-Stroke Natural Gas Engines

2019 ◽  
Author(s):  
Taylor F. Linker ◽  
Mark Patterson ◽  
Greg Beshouri ◽  
Abdullah U. Bajwa ◽  
Timothy J. Jacobs
Keyword(s):  
Natural Gas ◽  
Chemical Properties ◽  
Prediction Method ◽  
Operating Conditions ◽  
Combustion Mechanism ◽  
Nox Emissions ◽  
Lean Burn ◽  
Nox Formation ◽  
Gas Combustion ◽  
No2 Formation

Abstract The increased production of natural gas harvested from unconventional sources, such as shale, has led to fluctuations in the species composition of natural gas moving through pipelines. These variations alter the chemical properties of the bulk gas mixture and, consequently, affect the operation of pipeline compressor engines which use the gas as fuel. Among several possible ramifications of these variations is that of unacceptably high engine-out NOx emissions. Therefore, engine controller enhancements which can account for fuel variability are necessary for maintaining emissions compliance. Having the means to predict NOx emissions from a field engine can inform the development of such control schemes. There are several types of compressor engines; however, this study considers a large bore, lean-burn, two-stroke, integral compressor engine. This class of engine has unique operating conditions which make the formation of engine-out NOx different from typical automotive spark-ignited engines. For this reason, automotive-based methods for predicting NOx emissions are not sufficiently accurate. In this study, an investigation is performed on the possible NO and NO2 formation pathways which could be contributing to exhaust emissions. Additionally, a modeling method is proposed to predict engine-out NOx emissions using a 0-D/1-D model of a Cooper-Bessemer GMWH-10C compressor engine. Predictions are achieved with GRI-Mech3.0, a natural gas combustion mechanism, which allows for simulated formation of NOx species. The implemented technique is tuned using experimental data from a field engine to better predict emissions over a range of engine operating conditions. Tuning the model led to acceptable agreement across operating points varying in both load and trapped equivalence ratio.

scholarly journals Lean-Burn Natural Gas Engines: Challenges and Concepts for an Efficient Exhaust Gas Aftertreatment System

2020 ◽  
Author(s):  
Patrick Lott ◽  
Olaf Deutschmann
Keyword(s):  
Natural Gas ◽  
Carbon Dioxide Emissions ◽  
Rational Design ◽  
Catalytic Converter ◽  
Pollutant Emissions ◽  
Exhaust Gas ◽  
Lean Burn ◽  
Aftertreatment System ◽  
Natural Gas Engines ◽  
Exhaust Gas Aftertreatment

AbstractHigh engine efficiency, comparably low pollutant emissions, and advantageous carbon dioxide emissions make lean-burn natural gas engines an attractive alternative compared to conventional diesel or gasoline engines. However, incomplete combustion in natural gas engines results in emission of small amounts of methane, which has a strong global warming potential and consequently makes an efficient exhaust gas aftertreatment system imperative. Palladium-based catalysts are considered as most effective in low temperature methane conversion, but they suffer from inhibition by the combustion product water and from poisoning by sulfur species that are typically present in the gas stream. Rational design of the catalytic converter combined with recent advances in catalyst operation and process control, particularly short rich periods for catalyst regeneration, allow optimism that these hurdles can be overcome. The availability of a durable and highly efficient exhaust gas aftertreatment system can promote the widespread use of lean-burn natural gas engines, which could be a key step towards reducing mankind’s carbon footprint.

scholarly journals Cyclic Combustion Variations in Dual Fuel Partially Premixed Pilot-Ignited Natural Gas Engines

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
K. K. Srinivasan ◽  
S. R. Krishnan ◽  
Y. Qi
Keyword(s):  
Natural Gas ◽  
Dual Fuel ◽  
Nox Emissions ◽  
Natural Gas Engines ◽  
Percentage Points ◽  
Combustion Modes ◽  
Diesel Injection ◽  
Cyclic Variations ◽  
Partially Premixed ◽  
Dual Fueling

Dual fuel pilot-ignited natural gas engines are identified as an efficient and viable alternative to conventional diesel engines. This paper examines cyclic combustion fluctuations in conventional dual fuel and in dual fuel partially premixed combustion (PPC). Conventional dual fueling with 95% (energy basis) natural gas (NG) substitution reduces NOx emissions by almost 90% relative to neat diesel operation; however, this is accompanied by 98% increase in HC emissions, 10 percentage points reduction in fuel conversion efficiency (FCE) and 12 percentage points increase in COVimep. Dual fuel PPC is achieved by appropriately timed injection of a small amount of diesel fuel (2–3% on an energy basis) to ignite a premixed natural gas–air mixture to attain very low NOx emissions (less than 0.2 g/kWh). Cyclic variations in both combustion modes were analyzed by observing the cyclic fluctuations in start of combustion (SOC), peak cylinder pressures (Pmax), combustion phasing (Ca50), and the separation between the diesel injection event and Ca50 (termed “relative combustion phasing”). For conventional dual fueling, as NG substitution increases, Pmax decreases, SOC and Ca50 are delayed, and cyclic variations increase. For dual fuel PPC, as diesel injection timing is advanced from 20 deg to 60 deg BTDC, Pmax is observed to increase and reach a maximum at 40 deg BTDC and then decrease with further pilot injection advance to 60 deg BTDC, the Ca50 is progressively phased closer to TDC with injection advance from 20 deg to 40 deg BTDC, and is then retarded away from TDC with further injection advance to 60 deg BTDC. For both combustion modes, cyclic variations were characterized by alternating slow and fast burn cycles, especially at high NG substitutions and advanced injection timings. Finally, heat release return maps were analyzed to demonstrate thermal management strategies as an effective tool to mitigate cyclic combustion variations, especially in dual fuel PPC.

A New Global Algebraic NOx Emissions Formation Model for Natural Gas Engines

MTZ worldwide ◽  
2015 ◽  
Vol 76 (12) ◽  
pp. 42-47
Author(s):  
Georgios Bikas ◽  
Konstantinos Michos ◽  
Ioannis Vlaskos
Keyword(s):  
Natural Gas ◽  
Nox Emissions ◽  
Formation Model ◽  
Natural Gas Engines

scholarly journals Impact of Oxidation Catalysts on Exhaust NO2/NOx Ratio from Lean-Burn Natural Gas Engines

2010 ◽  
Vol 60 (7) ◽  
pp. 867-874 ◽  
Author(s):  
Daniel B. Olsen ◽  
Morgan Kohls ◽  
Gregg Arney
Keyword(s):  
Natural Gas ◽  
Oxidation Catalysts ◽  
Lean Burn ◽  
Natural Gas Engines
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