Strategies and Technologies for Improving Air Quality Around Ports
Increased activity at ports is an indication of economic development and growth; however, it also puts public health, regional air quality and global climate at risk because the exhaust from the marine diesel engines is not subjected to the stringent regulations as on-road engines. This dissertation characterizes the effectiveness of strategies and technologies to mitigate criteria pollutants and the long-lived greenhouse gas, carbon dioxide (CO2) from marine diesel engines. The dissertation also provides insight into the current state-of-art of gaseous and particulate matter portable emission measurement system (PEMS). Results from a project show how to determine the measurement allowance for PEMS in order to provide accurate measurements for the development of emission inventories and subsequently, air pollution mitigating regulations.
In-use gaseous emissions from the two main engines were measured at sea for the first time in order to evaluate the performance of a Code of Federal Regulations (CFR) compliant PEMS against instruments meeting the simplified measurement method (SMM) complaint with International Maritime Organization (IMO).
For the first time, emissions were measured from a modern container vessel with newest engine technologies. The vessel was operated on marine gas oil, a cleaner fuel, in regulated waters and on heavy fuel oil in unregulated waters. Impact of cleaner fuel and newest technologies on the engine was assessed. A simple equation was developed to estimate time required to completely switch fuels which can be used by vessel owners to comply with regional/international fuel regulations.
Vessel speed reduction (VSR), which is a worldwide acceptable strategy for ocean-going vessels (OGVs), was evaluated. The study showed that putting a speed limit on a container OGVs as they sail near ports and coastlines could cut emissions of air pollutants by up to 70%. This study also found that by reducing the vessel speed by a mere 3-6 knots from cruise speed will result in significant reductions of criteria pollutants and carbon dioxide.
Towards the goal of reducing emissions and dependency on fossil fuels, this dissertation explores benefits of consuming hydrotreated algae biofuel in small marine diesel engines for the first time. Significant particulate matter (PM2.5) and nitrogen oxides (NOx) benefits were reported with slight improve in fuel economy when fuel was switched from ultra low sulfur diesel (ULSD) to 50:50 blend of ULSD and algae fuels.
The dissertation investigates the benefits associated with the hybridization of the tugboat. A conventional tugboat was retrofitted with one auxiliary engine, shaft generators, addition of lithium polymer batteries and an energy management system. Up to 30% reduction in NOx, PM2.5 and CO2 was found. The energy management system in the hybrid tugboat allows the use of the auxiliary engine for propulsion as opposed to the only main engines during transit mode, thus leading to the significant reductions.
Another section of this dissertation provides an evaluation of latest PM-PEMS under different environmental and in-use conditions and features performance, accuracy and precision of PM-PEMS compared to the gravimetric reference method. The research from this study shows current PM-PEMS typically underreport the PM emissions compared to the reference method, with the exception of PEMS with photo-acoustic technology which incorporated a gravimetric filter. All PM-PEMS under evaluation performed poorly when encountered with sulfate laden PM during diesel particulate filter (DPF) regeneration.