Aerosol emissions of a ship diesel engine operated with diesel fuel or heavy fuel oil

Abstract

Gaseous and particulate emissions from a ship diesel research engine were elaborately analysed by a large assembly of measurement techniques. Applied methods comprised of offline and online approaches, yielding averaged chemical and physical data as well as time-resolved trends of combustion by-products. The engine was driven by two different fuels, a commonly used heavy fuel oil (HFO) and a standardised diesel fuel (DF). It was operated in a standardised cycle with a duration of 2 h. Chemical characterisation of organic species and elements revealed higher concentrations as well as a larger number of detected compounds for HFO operation for both gas phase and particulate matter. A noteworthy exception was the concentration of elemental carbon, which was higher in DF exhaust aerosol. This may prove crucial for the assessment and interpretation of biological response and impact via the exposure of human lung cell cultures, which was carried out in parallel to this study. Offline and online data hinted at the fact that most organic species in the aerosol are transferred from the fuel as unburned material. This is especially distinctive at low power operation of HFO, where low volatility structures are converted to the particulate phase. The results of this study give rise to the conclusion that a mere switching to sulphur-free fuel is not sufficient as remediation measure to reduce health and environmental effects of ship emissions.

Brown and Black Carbon Emitted by a Marine Engine Operated on Heavy Fuel Oil and Distillate Fuels: Optical Properties, Size Distributions, and Emission Factors

“…Overall, light absorption by OM in DF and MGO exhaust was found to be negligible, whereas absorption by OM in HFO PM was very significant. This result was not surprising considering the near black color of the HFO fuel (diesel is almost transparent) and the molecular similarity between HFO‐exhaust OM and the fuel (Sippula et al, ; Streibel et al, ). In more detail, our conclusions are as follows.…”

“…In addition, differences in fuel composition may influence marine engine PM optical properties. Since the molecular composition of HFO PM has been shown to be comparable with the molecular composition of HFO (Streibel et al, 2017), in a manner depending on engine load (Sippula et al, 2014), we hypothesize that the molecular composition of brC is also related to the molecular composition of the fuel. In support of this hypothesis, we note that Sippula et al (2014) observed larger mass fractions of PAHs in HFO OM at lower engine loads, similar to our observation of increased MAC OM at lower engine loads.…”

“…In considering Figure 3 relative to previous studies (Mueller et al, 2015;Oeder et al, 2015;Streibel et al, 2017), it is important to realize that the SP2-measured d rBC is a volume-equivalent diameter, which is by definition smaller than d mob for soot particles of both open and compact morphologies (Kulkarni et al, 2011). For the two size distributions in Figure 3 to overlap, a size-independent shape factor of ∼2.2 is required.…”

Infrared-absorbing carbonaceous tar can dominate light absorption by marine-engine exhaust

“…5a, and because multiple soluble molecules found in HFO fuel have also been detected in HFO-PM. 36,46 To test this hypothesis, we performed stepwise solvent extraction of four HFO-PM filter samples, measuring the sample absorption after each step. The results for a representative filter are shown in Fig.…”

Characteristics of marine shipping emissions at berth: profiles for particulate matter and volatile organic compounds

“…A recent comparative study focused on HFO and MDO in the European sulfur emission control area (SECA) showed that a decline in sulfur content from 0.48 to 0.092 % led to a reduction of 67 % in PM mass and 80 % in SO 2 emissions (Zetterdahl et al, 2016). Another comprehensive study including PM, EC and heavy metals was undertaken to compare HFO and standardized diesel fuel (Streibel et al, 2017). Following the regulations for using low sulfur fuels implemented by western countries, China began to launch its own stepwise regulations associated with domestic emission control areas (DECAs) to minimize conventional pollutants from shipping emissions.…”