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Natural Gas Engine Emission Reduction by Catalysts

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Original languageEnglish
Pages (from-to)142-152
Number of pages10
JournalEmission Control Science and Technology
Issue number2
Early online date23 Dec 2016
Publication statusPublished - Jun 2017
Publication typeA1 Journal article-refereed


In order to meet stringent emission limits, after-treatment systems are increasingly utilized in natural gas engine applications. In this work, two catalyst systems were studied in order to clarify how the catalysts affect, e.g. hydrocarbons, NOx and particles present in natural gas engine exhaust. A passenger car engine modified to run with natural gas was used in a research facility with possibilities to modify the exhaust gas properties. High NOx reductions were observed when using selective catalytic reduction, although a clear decrease in the NOx reduction was recorded at higher temperatures. The relatively fresh methane oxidation catalyst was found to reach reductions greater than 50% when the exhaust temperature and the catalyst size were sufficient. Both the studied catalyst systems were found to have a significant effect on particulate emissions. The observed particle mass reduction was found to be due to a decrease in the amount of organics passing over the catalyst. However, especially at high exhaust temperatures, high nanoparticle concentrations were observed downstream of the catalysts together with higher sulphate concentrations in particles. This study contributes to understanding emissions from future natural gas engine applications with catalysts in use.

Publication forum classification

Field of science, Statistics Finland