Abstract
The effect of adding hydrogen to methane as a fuel for spark ignited engines has been extensively investigated. Both the possibility of adding a limited amount of hydrogen as well as equal amounts of hydrogen and carbon dioxide to natural gas has been investigated. A 10 vol% addition of hydrogen to the natural gas caused a reduction in UHC of approximately 40%, and an increase in efficiency of approximately three percentage points at the test engine. It is unknown if the gain is representative for large engines. Similar results for UHC reduction and efficiency were obtained for combined hydrogen and carbon dioxide addition. The carbon dioxide was added by exhaust gas recirculation. However, the price of hydrogen, makes this idea uneconomical even when carbon dioxide is readily available through recirculation of engine exhaust. Adiabatic prereforming may be used to convert natural gas into methane, hydrogen and carbon dioxide in order to generate hydrogen and at the same time increase the methane number. The process has been found to be competitive with adding of hydrogen but it is still not economical. The effect of NO/NO{sub 2} on methane oxidation has been studied both theoretically and experimentally. A detailed kinetic modelling study
More>>
Karll, B;
Kristensen, P G;
Nielsen, M;
Iskov, H;
[1]
Broe Bendtsen, A;
Glarborg, P;
Dam-Johansen, K
[2]
- Danish Gas Technology Centre a/s (Denmark)
- Technical University of Denmark. CHEC, Department of Chemical Engineering (Denmark)
Citation Formats
Karll, B, Kristensen, P G, Nielsen, M, Iskov, H, Broe Bendtsen, A, Glarborg, P, and Dam-Johansen, K.
Lean-burn engines UHC emission reduction.
Denmark: N. p.,
1999.
Web.
Karll, B, Kristensen, P G, Nielsen, M, Iskov, H, Broe Bendtsen, A, Glarborg, P, & Dam-Johansen, K.
Lean-burn engines UHC emission reduction.
Denmark.
Karll, B, Kristensen, P G, Nielsen, M, Iskov, H, Broe Bendtsen, A, Glarborg, P, and Dam-Johansen, K.
1999.
"Lean-burn engines UHC emission reduction."
Denmark.
@misc{etde_10147850,
title = {Lean-burn engines UHC emission reduction}
author = {Karll, B, Kristensen, P G, Nielsen, M, Iskov, H, Broe Bendtsen, A, Glarborg, P, and Dam-Johansen, K}
abstractNote = {The effect of adding hydrogen to methane as a fuel for spark ignited engines has been extensively investigated. Both the possibility of adding a limited amount of hydrogen as well as equal amounts of hydrogen and carbon dioxide to natural gas has been investigated. A 10 vol% addition of hydrogen to the natural gas caused a reduction in UHC of approximately 40%, and an increase in efficiency of approximately three percentage points at the test engine. It is unknown if the gain is representative for large engines. Similar results for UHC reduction and efficiency were obtained for combined hydrogen and carbon dioxide addition. The carbon dioxide was added by exhaust gas recirculation. However, the price of hydrogen, makes this idea uneconomical even when carbon dioxide is readily available through recirculation of engine exhaust. Adiabatic prereforming may be used to convert natural gas into methane, hydrogen and carbon dioxide in order to generate hydrogen and at the same time increase the methane number. The process has been found to be competitive with adding of hydrogen but it is still not economical. The effect of NO/NO{sub 2} on methane oxidation has been studied both theoretically and experimentally. A detailed kinetic modelling study of the UHC conversion dependency of exhaust gas parameters is reported and the project has contributed to the theoretical understanding of the oxidation chemistry. Both NO and NH{sub 3} addition to the engine inlet was used to increase the NO{sub x} level, and the general trend was a decrease in UHC as the NO{sub x} level increased, both in cylinger, manifold and rector. From the data it is concluded that NO and NH{sub 3} addition have identical effects. The results show a 15-35% decrease in manifold UHC. However, the increased emissions of NO{sub x} and CO associated with this process must be realised. Field tests show a 28% UHC reduction without an increase in CO emission. The UHC oxidation in the exhaust reactor has been tested at increased NO{sub x} levels and the results show that increased NO{sub x} levels improve the UHC conversion in the exhaust reactor. The process is found to be very dependent on actual NO{sub x} levels and the exhaust reactor temperature. The exhaust temperature from lean burn engines is in the range from 450 to 550 deg. C depending on the engine settings and type. The conclusion from the tests shows that only if the temperature in the exhaust system is raised, it will be possible to use the NO{sub x} enhanced UHC oxidation process for post oxidation. Injection of hydrogen peroxide caused a significant reduction in the stack emission of UHC by conversion of UHC at conditions where the exhaust reactor otherwise was unable to oxidise UHC. The stack emissin of UHC was reduced by 40-60% during test engine conditions. (EHS) EFP-96; 14 refs.}
place = {Denmark}
year = {1999}
month = {Apr}
}
title = {Lean-burn engines UHC emission reduction}
author = {Karll, B, Kristensen, P G, Nielsen, M, Iskov, H, Broe Bendtsen, A, Glarborg, P, and Dam-Johansen, K}
abstractNote = {The effect of adding hydrogen to methane as a fuel for spark ignited engines has been extensively investigated. Both the possibility of adding a limited amount of hydrogen as well as equal amounts of hydrogen and carbon dioxide to natural gas has been investigated. A 10 vol% addition of hydrogen to the natural gas caused a reduction in UHC of approximately 40%, and an increase in efficiency of approximately three percentage points at the test engine. It is unknown if the gain is representative for large engines. Similar results for UHC reduction and efficiency were obtained for combined hydrogen and carbon dioxide addition. The carbon dioxide was added by exhaust gas recirculation. However, the price of hydrogen, makes this idea uneconomical even when carbon dioxide is readily available through recirculation of engine exhaust. Adiabatic prereforming may be used to convert natural gas into methane, hydrogen and carbon dioxide in order to generate hydrogen and at the same time increase the methane number. The process has been found to be competitive with adding of hydrogen but it is still not economical. The effect of NO/NO{sub 2} on methane oxidation has been studied both theoretically and experimentally. A detailed kinetic modelling study of the UHC conversion dependency of exhaust gas parameters is reported and the project has contributed to the theoretical understanding of the oxidation chemistry. Both NO and NH{sub 3} addition to the engine inlet was used to increase the NO{sub x} level, and the general trend was a decrease in UHC as the NO{sub x} level increased, both in cylinger, manifold and rector. From the data it is concluded that NO and NH{sub 3} addition have identical effects. The results show a 15-35% decrease in manifold UHC. However, the increased emissions of NO{sub x} and CO associated with this process must be realised. Field tests show a 28% UHC reduction without an increase in CO emission. The UHC oxidation in the exhaust reactor has been tested at increased NO{sub x} levels and the results show that increased NO{sub x} levels improve the UHC conversion in the exhaust reactor. The process is found to be very dependent on actual NO{sub x} levels and the exhaust reactor temperature. The exhaust temperature from lean burn engines is in the range from 450 to 550 deg. C depending on the engine settings and type. The conclusion from the tests shows that only if the temperature in the exhaust system is raised, it will be possible to use the NO{sub x} enhanced UHC oxidation process for post oxidation. Injection of hydrogen peroxide caused a significant reduction in the stack emission of UHC by conversion of UHC at conditions where the exhaust reactor otherwise was unable to oxidise UHC. The stack emissin of UHC was reduced by 40-60% during test engine conditions. (EHS) EFP-96; 14 refs.}
place = {Denmark}
year = {1999}
month = {Apr}
}