Real-Time Gaseous, PM and Ultrafine Particle Emissions from a Modern Marine Engine Operating on Biodiesel

Abstract

Emissions from harbor-craft significantly affect air quality in populated regions near ports and inland waterways. This research measured regulated and unregulated emissions from an in-use EPA Tier 2 marine propulsion engine on a ferry operating in a bay following standard methods. A special effort was made to monitor continuously both the total Particulate Mass (PM) mass emissions and the real-time Particle Size Distribution (PSD). The engine was operated following the loads in ISO 8178-4 E3 cycle for comparison with the certification standards and across biodiesel blends. Real-time measurements were also made during a typical cruise in the bay. Results showed the in-use nitrogen oxide (NOx) and PM(2.5) emission factors were within the not to exceed standard for Tier 2 marine engines. Comparing across fuels we observed the following: a) no statistically significant change in NO(x) emissions with biodiesel blends (B20, B50); b) ∼ 16% and ∼ 25% reduction of PM(2.5) mass emissions with B20 and B50 respectively; c) a larger organic carbon (OC) to elemental carbon (EC) ratio and organic mass (OM) to OC ratio with B50 compared to B20 and B0; d) a significant number of ultrafine nuclei and a smaller mass mean diameter with increasing blend-levels of biodiesel. The real-time monitoring of gaseous and particulate emissions during a typical cruise in the San Francisco Bay (in-use cycle) revealed important effects of ocean/bay currents on emissions: NO(x) and CO(2) increased 3-fold; PM(2.5) mass increased 6-fold; and ultrafine particles disappeared due to the effect of bay currents. This finding has implications on the use of certification values instead of actual in-use emission values when developing inventories. Emission factors for some volatile organic compounds (VOCs), carbonyls, and poly aromatic hydrocarbons (PAHs) are reported as supplemental data.

Characteristics and temporal evolution of particulate emissions from a ship diesel engine

“…The average OM/OC ratios were derived from HR-ToF-AMS. The OM/OC ratios are higher than the commonly used factor of $1.2 for combustion aerosols [43] but comparable to previous measurements of ship diesel or biodiesel emissions [44].…”

Black carbon from ships: a review of the effects of ship speed, fuel quality and exhaust gas scrubbing

“…A reanalysis of the BC data from Lack et al (2008b) (using the cubic function between engine load and speed to calculate engine loads, (speed α engine load 3 )) also show this inverse relationship for 101 vessels. In contrast, some studies that show a direct relationship between engine load and BC emissions Jayaram et al, 2011). Figure 2 (and Table 1) show all data of BC emissions and engine load available (we note that some data may exist that is not accessible to us), all of which are normalized to a BC emission factor (EF BC ) of 1 kg −1 at 85-100 % engine load -typical of in-service maximum engine loads at unrestricted cruise speeds.…”

Comparison of Vehicle Exhaust Particle Size Distributions Measured by SMPS and EEPS During Steady-State Conditions

“…The CVS dilution air was HEPA-filtered. For diesel generator emissions, a mini-dilution tunnel (ISO-8178-1; Jayaram et al 2011), which is equipped with a single venturi following ISO-8178-1, was used to provide a secondary dilution ratio of 9.5. The measurements on the PFI vehicle was conducted in the CARB Haagen-Smit Laboratory (HSL) located in El Monte, CA.…”