排放控制区政策下船舶辅机大气污染物排放特征研究

Emission characteristics of air pollutants from marine auxiliaries under ECA policy

船舶运输业蓬勃发展的同时,也向大气中排放了大量有害气体.为此我国制定了分阶段实施的船舶排放控制区政策,以期通过限制燃油含硫量控制船舶大气污染问题.本研究于2016年和2018年在排放控制区政策实施前后,连续对A船和B船2艘万吨级航海船进行登船实测,使用"碳平衡法"计算了船舶尾气中各类污染物基于燃油消耗量的排放因子.结果表明,A船、B船由使用含硫量为2.20%和2.10%的燃油转为使用含硫量为0.470%和0.003%的燃油后,SO2排放因子分别由44.00 g·kg^-1和42.00 g·kg^-1下降到9.40 g·kg^-1和0.80 g·kg^-1,PM2.5排放因子分别由2.44 g·kg^-1和1.02 g·kg^-1下降到0.870 g·kg^-1和0.003 g·kg^-1,TVOC排放因子则分别由0.061 g·kg^-1和0.106 g·kg^-1升高到0.292 g·kg^-1和0.706 g·kg^-1.对比使用不同含硫量燃油时船舶PM2.5的减排情况发现,现阶段以燃油含硫量≤0.5%为限值的排放控制区政策,以及即将推行的以燃油含硫量≤0.1%为限值的排放控制区政策都能有效地降低船舶颗粒物排放.在成分特征方面,转用含硫量更低的燃油后,A船、B船PM2.5中硫酸盐在水溶性离子中的占比分别由58.6%和44.3%下降到18.1%和7.9%;PM2.5中钒元素含量分别降低了82.5%和98.9%,镍元素含量分别降低了20.8%和98.5%;VOCs中烯烃占比分别提高了11.9%和19.3%,而芳香烃占比则分别下降了32.0%和4.5%.由于排放控制区政策实施以后,船舶排放的颗粒物中钒元素的含量大幅减少,钒元素将不再适合作为船舶大气污染示踪物.

With the rapid development of ship transportation,a large number of harmful pollutants were discharged into the atmosphere.Therefore,China has formulated a phased implementation of emission control areas(ECA)to control the air pollution from ships.In 2016 and 2018,measurements have been carried out on board of two navigation ships before and after the implementation of ECA Policy.The fuel-based emission factors of the ships were calculated.The results showed that after conversion of fuel with Sulfur content of 2.20%and 2.10%to fuel with Sulfur content of 0.470%and 0.003%,the SO2 emission factors of ship A and ship B declined from 44.00 g·kg^-1 and 42.00 g·kg^-1 to 9.40 g·kg^-1 and 0.80 g·kg^-1 correspondingly.The PM2.5 emission factors reduction counted from ship A and ship B were 2.44 g·kg^-1 and 1.02 g·kg^-1 to 0.870 g·kg^-1 and 0.003 g·kg^-1 while TVOC emission factors enhanced from 0.061 g·kg^-1 and 0.106 g·kg^-1 to 0.292 g·kg^-1 and 0.706 g·kg^-1 respectively.Comparing the reduction of PM2.5 EFs under different fuels,we found that ECA Policy at this stage(fuel sulfur content≤0.5%)and in the next stage(fuel sulfur content≤0.1%)can both effectively reduce the emission of PM2.5 from the ships.In terms of composition characteristics,the proportion of sulfate in PM2.5 of ship A and ship B reduced from 58.6%and 44.3%to 18.1%and 7.9%correspondingly.The reduction in Vanadium content in PM2.5 was 82.5%and 98.9%,whereas Nickel decreased by 20.8%and 98.5%correspondingly.The alkene proportion in VOCs increased by 11.9%to 19.3%,while the proportion of aromatic decreased by 32.0%and 4.5%respectively.Since the implementation of ECA Policy,Vanadium discharged from ships has been significantly reduced and it is no longer suitable to perform as a tracer of air pollution from ships.