Selective catalytic reduction operation with heavy fuel oil: NOx, NH3, and particle emissions

Kati Lehtoranta, Hannu Vesala, Päivi Koponen, Satu Korhonen

    Research output: Contribution to journalArticleScientificpeer-review

    20 Citations (Scopus)

    Abstract

    To meet stringent NOx emission limits, selective catalytic reduction (SCR) is increasingly utilized in ships, likely also in combination with low-priced higher sulfur level fuels. In this study, the performance of SCR was studied by utilizing NOx, NH3, and particle measurements. Urea decomposition was studied with ammonia and isocyanic acid measurements and was found to be more effective with heavy fuel oil (HFO) than with light fuel oil. This is suggested to be explained by the metals found in HFO contributing to metal oxide particles catalyzing the hydrolysis reaction prior to SCR. At the exhaust temperature of 340°C NOx reduction was 85-90%, while at lower temperatures the efficiency decreased. By increasing the catalyst loading, the low temperature behavior of the SCR was enhanced. The drawback of this, however, was the tendency of particle emissions (sulfate) to increase at higher temperatures with higher loaded catalysts. The particle size distribution results showed high amounts of nanoparticles (in 25-30 nm size), the formation of which SCR either increased or decreased. The findings of this work provide a better understanding of the usage of SCR in combination with a higher sulfur level fuel and also of ship particle emissions, which are a growing concern.
    Original languageEnglish
    Pages (from-to)4735-4741
    JournalEnvironmental Science & Technology
    Volume49
    Issue number7
    DOIs
    Publication statusPublished - 2015
    MoE publication typeA1 Journal article-refereed

    Keywords

    • airships
    • catalysts
    • fuel oils
    • fuels
    • oil shale
    • particle size
    • particle size analysis
    • reduction
    • ships
    • sulfur
    • temperature
    • urea
    • xhaust temperature
    • hydrolysis reaction
    • low temperature behavior
    • lower temperatures
    • metal oxide particles
    • particle emissions
    • particle measurement
    • urea decomposition

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