甲醇燃料的船用发动机对空气排放的测量

Emissions of exhaust gases and particulate matter from a dual fuel marine engine using methanol as fuel with marine gasoil as pilot fuel have been examined for a ferry during operation.The emission factor for nitrogen oxides is lower than what is typically found for marine gasoil but does not reach the tier III limit.The emissions of particulate matter are significantly lower than for fuel oils and similar to what is found for LNG engines.The main part of the particles can be found in the ultrafine range with the peak being at around 18 nm.About 93%of the particles are evaporated and absorbed when using a thermodenuder,and thus a large majority of the particles are volatile.Methanol is a potential future marine fuel that will reduce emissions of air pollutants and can be made as a biofuel to meet emission targets for greenhouse gases.

Impact of Aromatic Concentration in Marine Fuels on Particle Emissions

The fuel sulfur content in marine fuels has been regulated in Sulfur Emission Control Areas(SECAs) since January 2015. However, other fuel characteristics are also believed to have an impact on particle emissions, particularly on the number of particles emitted. This study investigates the impact of the content of aromatics in fuel. To achieve fuel blends with concentrations of aromatics similar to those found in marine fuel oils, i.e. 20%–30% by volume(%vol.), normal diesel oil(4%–5% vol. aromatics) is doped with a mixture of aromatics. Emission measurements are conducted in test-bed engine facilities and particle emissions over a wide size range are analyzed. Results show a decreased number of particles emitted(or not change) with an increase in the aromatic concentration in fuel. This is because there is a reduction in the cetane number of the fuel with an increased aromatic content, which effects the combustion process and results in decreased particle formation. However, when ignition improver is used to increase the cetane number, particle emissions remain at a lower level than for normal diesel oil; thereby emphasizing the presence of other factors in the formation of particles.

减少海洋航运环境排放的新方法

Maritime shipping is a strategic sector with a strong international vocation and management.The need to define regulations valid for many different countries without generating disparities of treatment slowed down the formulation of environmental regulations,especially for atmospheric emissions.In particular,regulations pertaining to the reduction of sulphur compounds allowed two distinct approaches:the use of low-sulphur fuels or exhaust gas cleaning systems,the so-called Scrubbers.The actual implementation of these solutions presents specific concerns either related to the toxicity of atmospheric by-products and to the fuel cost or to the generation of polluting washwaters that may need treatment before discharge.In this paper we analyzed the potential environmental benefit deriving from the use of a distillate fuel,not compliant with current IMO Sulphur Regulations,together with a Scrubber.The pilot-scale experimental results indicated that a limited amount of water and/or scrubber volume is needed to reduce sulphur emissions below regulations on maritime shipping,especially with the addition of NaOH reaching a water-saving between 25%-33%compared to the use of pure seawater.Experiments indicated that scrubber washwater PAHs emissions are within the available water quality standards indicated by EU and USA guidelines.A bottom-up analysis on heavy metals concentration shed light on the prominent role of metal-parts corrosion on the washwater emissions.Taking into account for corrosion phenomena,the actual heavy metals concentration in the washwater deriving from scrubbing was normally below the water quality standards.