Controlling emissions of natural gas engines: Final report

Kati Lehtoranta, Timo Murtonen, Hannu Vesala, Päivi Koponen, Jenni Alanen, Topi Rönkkö, Pauli Simonen, Sanna Saarikoski, Hilkka Timonen

    Research output: Book/ReportReport


    The CENGE project focuses on characterization of gas engine emissions comprehensively and studies the effect of different techniques on the emission formation. In addition different emission measurement methods are studied. To mimic the emission matrix of 4 stroke medium speed gas engine a new test facility is developed. The project is based on experiments conducted in engine laboratory and on power plant. Measurements of natural gas engine exhaust gas emissions resulted to rather high levels of hydrocarbons and carbon monoxide. The main HC component was methane while ethane, propane and ethylene were also found. These components are found also in the natural gas. The NOx and particle mass emissions were low. However, significant amount of nanoparticles
    was found in the exhaust.
    Several different catalysts were studied, including SCRs, oxidation catalysts, a methane oxidation catalyst (still under development) and combinations of those. 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. At all measurement campaigns catalysts were found to decrease the emissions of particulate matter total mass. However, nanoparticle number
    concentrations were increased by a catalyst combined with high exhaust temperatures. In one experiment, the behaviour was connected to sulphur compounds while in the other, by contrast, the increase in particle emission at higher catalyst temperatures was due to an increase in organics. The engine out particle emissions between these measurements differed also, one explanation to this being the change of lubricating oil. In addition to primary particle emissions, secondary emission was studied utilizing a potential aerosol mass (PAM) chamber: the particle mass measured downstream the PAM chamber, was found to be 6-170 times as high as the mass of the emitted primary exhaust particles.
    The fraction of organics was approximately half of the produced secondary aerosol mass.
    Original languageEnglish
    PublisherVTT Technical Research Centre of Finland
    Number of pages60
    Publication statusPublished - 2017
    MoE publication typeD4 Published development or research report or study

    Publication series

    SeriesVTT Research Report


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