Typical and Atypical Morphology of Non-volatile Particles from a Diesel and Natural Gas Marine Engine

Alberto Baldelli,J Wayne Miller,Una Trivanovic,Patrick Kirchen,Prem Lobo,Steven Rogak,Joel C Corbin,Stephanie Gagné

doi:10.4209/aaqr.2020.01.0006

Alberto Baldelli, J Wayne Miller + Show 6 more

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https://doi.org/10.4209/aaqr.2020.01.0006

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Abstract

Non-volatile particle emissions from a marine engine fueled by either diesel or natural gas (NG) blended with diesel pilot gas were investigated via transmission electron microscopy (TEM). The most common particles (> 95% by number) were soot aggregates. These “typical” aggregates exhibited primary particle diameters of 20.7 ± 1.9 and 26.9 ± 1.7 for 100 nm aggregates when diesel and NG fuel were used, respectively. Highly non-uniform aggregates, with distinct groups of smaller and larger monomers, were visible in all of the samples but occurred most frequently with diesel fueling at high loads. The observed “atypical” particles included super-aggregates, small compact aggregates, spheres, mineral-like polyhedral particles, and fibers. Such particles, although rare (averaging 3% by number, as calculated by counting the number of particles for each type depicted in all of the collected images), were found in most of the samples and could have been produced by a variety of mechanisms. For instance, the spheres (approximately 300 nm in diameter) most likely arose from metals within the lubricating oil.

Highlights

Carbonaceous aerosols such as soot have an impact on the environment and human health (Janssen et al, 2011)
Non-volatile particle emissions from a marine engine fueled by either diesel or natural gas (NG) blended with diesel pilot gas were investigated via transmission electron microscopy (TEM)
The consistency of results for diesel and NG in this engine could support the hypothesis (Corbin et al, 2019) that in NG mode the soot particles originate from the diesel pilot fuel, rather than from the NG

Summary

Introduction

Carbonaceous aerosols such as soot have an impact on the environment and human health (Janssen et al, 2011). They are major contributors to radiative heating of the atmosphere (Jacobson, 2010). Different operating conditions, such as load, result in soot with different properties and with different impact on the environment (e.g., Gent et al, 2019). Diesel engine emissions are significant and are expected to increase with vehicle population.

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