Onboard Measurements of Nanoparticles from a SCR-Equipped Marine Diesel Engine

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• 作者：脜sa M. Hallquist ; Erik Fridell ; Jonathan Westerlund ; Mattias Hallquist
• 刊名：Environmental Science & Technology (ES&T)
• 出版年：2013
• 出版时间：January 15, 2013
• 年：2013
• 卷：47
• 期：2
• 页码：773-780
• 全文大小：448K
• 年卷期：v.47,no.2(January 15, 2013)
• ISSN：1520-5851

文摘

In this study nanoparticle emissions have been characterized onboard a ship with focus on number, size, and volatility. Measurements were conducted on one of the ship鈥檚 four main 12 600 kW medium鈥搒peed diesel engines which use low sulfur marine residual fuel and have a Selective Catalytic Reduction (SCR) system for NO_X abatement. The particles were measured after the SCR with an engine exhaust particle sizer spectrometer (EEPS), giving particle number and mass distributions in the size range of 5.6鈥?60 nm. The thermal characteristics of the particles were analyzed using a volatility tandem DMA system (VTDMA). A dilution ratio of 450鈥?20 was used which is similar to the initial real-world dilution. At a stable engine load of 75% of the maximum rated power, and after dilution and cooling of the exhaust gas, there was a bimodal number size distribution, with a major peak at 10 nm and a smaller peak at around 30鈥?0 nm. The mass distribution peaked around 20 nm and at 50鈥?0 nm. The emission factor for particle number, EF_PN, for an engine load of 75% in the open-sea was found to be 10.4 卤 1.6 脳 10¹⁶ (kg fuel)^鈭? and about 50% of the particles by number were found to have a nonvolatile core at 250 掳C. Additionally, 20 nm particles consist of 40% of nonvolatile material by volume (evaporative temperature 250 掳C), while the particles with a particle diameter <10 nm evaporate completely at a temperature of 130鈥?50 掳C. Emission factors for NO_X, CO, and CO₂ for an engine load of 75% in the open-sea were determined to 4.06 卤 0.3 g (kg fuel)^鈭?, 2.15 卤 0.06 g (kg fuel)^鈭?, and 3.23 卤 0.08 kg (kg fuel)^鈭?, respectively. This work contributes to an improved understanding of particle emissions from shipping using modern pollution reduction measures such as SCR and fuel with low sulfur content.