Abstract
Program goals for the Advanced Reciprocating Engine Systems (ARES) program of the Department of Energy include efficiency and environmental goals. Lean-burn natural gas engines offer higher efficiency than engines that operate with Stoichiometric air-to-fuel mixtures; however, the excess oxygen in the exhaust of lean engines makes NOx reduction with catalytic aftertreatment difficult. Thus, advancing efficiency via lean combustion results in challenges to meet environmental goals. The lean NOx trap catalyst technology is capable of reducing NOx in lean exhaust and, thereby, enables the potential for lean combustion to meet both efficiency and environmental goals. During lean NOx trap catalysis, NOx in oxygen-rich exhaust is trapped on the catalyst by alkali or alkaline earth-based sorbate materials; then, upon exposure to oxygen-depleted exhaust, the NOx is released and reduced to nitrogen in a process called regeneration. The regeneration process renews the catalyst for more NOx trapping; the cyclic process repeats at periods on the order of a minute. Oxygen depletion during regeneration is accomplished by temporarily operating the catalyst at rich air-to-fuel ratios; traditionally, a variety of methods have been utilized to achieve rich conditions for the catalyst. In this presentation, research of a lean NOx trap on a lean natural gas engine will be presented. Natural gas from the engine supply was used to provide the reductant for the lean NOx trap regeneration process. The natural gas is injected into the exhaust system where oxidation and reforming catalysts partially oxidize and/or reform the natural gas into reductants suitable for lean NOx trap regeneration. Studies of the natural gas oxidation and reforming processes and their relation to NOx reduction performance will be presented.
| Original language | English |
|---|---|
| Title of host publication | ASME 2005 Internal Combustion Engine Division Fall Technical Conference, ICEF 2005 |
| Publisher | American Society of Mechanical Engineers (ASME) |
| Pages | 393-404 |
| Number of pages | 12 |
| ISBN (Electronic) | 0791847365, 9780791847367 |
| DOIs | |
| State | Published - 2005 |
| Event | ASME 2005 Internal Combustion Engine Division Fall Technical Conference, ICEF 2005 - Ottawa, Canada Duration: Sep 11 2005 → Sep 14 2005 |
Publication series
| Name | ASME 2005 Internal Combustion Engine Division Fall Technical Conference, ICEF 2005 |
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Conference
| Conference | ASME 2005 Internal Combustion Engine Division Fall Technical Conference, ICEF 2005 |
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| Country/Territory | Canada |
| City | Ottawa |
| Period | 09/11/05 → 09/14/05 |
Funding
Oak Ridge National Laboratory (ORNL) would like to acknowledge EmeraChem LLC for supply of the catalysts. This work is a part of the U. S. Department of Energy (DOE) Advanced Reciprocating Engine System (ARES) Program within the Office of Distributed Energy Resources. The ARES program, under the leadership of Ron Fiskum, is in cooperation with representatives from Caterpillar, Cummins, and Waukesha. Jim Tassitano performed work under a subcontract with Oak Ridge Associated Universities. ORNL is managed by UT-Battelle LLC for the US Department of Energy under subcontract DE-AC05-00OR22725. The U.S. Department of Energy and the California Energy Commission currently have research and development programs called Advanced Reciprocating Engine Systems (ARES) and Advanced Reciprocated Internal Combustion Engine (ARICE), respectively. Fuel efficiency and low emissions are two primary goals of these programs. The work presented here was funded in the ARES program and, thus, addresses the ARES 2010 goals of 50% thermal efficiency (fuel efficiency) and <0.1 g/bhp-hr NOx emissions. ARICE 2007 goals are 45% thermal efficiency and <0.015 g/bhp-hr NOx.