Lower NO<i><sub>x</sub></i> but higher particle and black carbon emissions from renewable diesel compared to ultra low sulfur diesel in at-sea operations of a research vessel

<p>Gas and particle emissions from R/V <i>Robert Gordon Sproul</i> were measured for ultra low sulfur diesel (ULSD) and hydrogenation derived renewable diesel (HDRD) during dedicated aerosol measurement cruises in 2014 (29 September–3 October) and 2015 (4–7 and 26–28 September). CO, CO<sub>2</sub>, and NO<sub>X</sub> were measured directly from the starboard stack from the 2-stroke, small bore, high speed engine, while number and mass size distributions for both particles and black carbon (BC) were measured by intercepting the ship plume. Measurements at constant engine speeds (1600 rpm, 1300 rpm, 1000 rpm, and 700 rpm) had emission factors of CO () and NO<sub>X</sub> that were lower by 20% and 13%, respectively, for HDRD compared to ULSD at 700 rpm. However, at 1600 rpm, and were within one standard deviation for both ULSD (: 4.0 ± 0.1 g [kg-fuel]<sup>−1</sup>; : 51 ± 0.8 g [kg-fuel]<sup>−1</sup>) and HDRD (: 3.9 ± 0.2 g [kg-fuel]<sup>−1</sup>; : 51 ± 2 g [kg-fuel]<sup>−1</sup>). HDRD emission factors of particle number and mass concentrations were higher than ULSD by 46% to 107% and 36% to 150%, respectively, at 1600, 1300, and 1000 rpm, but the differences were smaller than the cycle-to-cycle variability at 700 rpm. BC mass emission factors were nearly 200% larger for 700, 1000, and 1300 rpm for HDRD compared to ULSD, but the mass differences were smaller than cycle-to-cycle variability at 1600 rpm. BC mass size distributions showed that the peak diameter of the BC mass mode for ULSD (∼120 nm) is about 20 nm larger than for HDRD (∼100 nm), even though the particle mass and number size distributions are quite similar.</p> <p>Copyright © 2017 American Association for Aerosol Research</p>