WLTC循环下汽油车氨排放影响因素分析
|
摘要
为研究WLTC (worldwide light-duty test cycle,全球轻型汽车驾驶循环)循环下常规污染物和行驶工况对汽油车NH_3排放的影响,选定一辆满足国Ⅴ排放标准、配备TWC (three way catalyst,三元催化器)尾气后处理装置的轻型汽油车,测定其在WLTC循环下CO_2、CO、NO_x和NH_3的摩尔排放量.结果表明:CO、NO_x与NH_3排放的线性相关系数分别为0. 626和0. 321. NH_3高排放的出现除了伴有CO的高排放外,还需车辆具有高速和持续的正向加速度.用配备TWC尾气后处理装置前、后NO_x排放量的差值表示NO_x的转化量发现,NO_x的高转化量并不一定对应NH_3的高排放量,在循环后期大量产生的NO_x会抑制NH_3的排放.由于VSP (vehicle specific power,比功率)能综合反映行驶工况,研究行驶工况对NH_3排放的影响时主要分析VSP与NH_3之间的关系,通过VSP聚类方法将VSP划分为不同区间,得出当VSP Bin (vehicle specific power bin,比功率区间)大于0时,基于CO_2的NH_3排放基本呈随VSP Bin增大而增加的规律,并且基于CO_2的NH_3排放量最大值对应的VSP Bin为持续正向加速工况.研究显示,常规污染物中CO和NO_x对NH_3的排放会产生不同程度的影响,加速度作为行驶工况的表征参数之一会直接或通过影响CO和NO_x的排放间接影响NH_3的生成.
In order to study the effects of the conventional pollutants and driving conditions on the ammonia emission of gasoline vehicles under the WLTC cycle,the molar emissions of CO_2,CO,NO_xand ammonia were measured on the selected vehicles which met the China-5 emission standard and were equipped with three-way catalyst( TWC). The results showed that the linear correlation coefficients of CO,NO_xand ammonia emissions were 0. 626 and 0. 321,respectively. The high emission of ammonia was accompanied not only by high CO emission,but also by high speed and continuous positive acceleration. The differences of the NO_xemission concentrations between precatalyst and post catalyst were used to express the conversion amount of NO_x. It was found that the high conversion of NO_xdidn' t necessarily correspond to the high emission of ammonia. In the later stage of the cycle,the large amount of NO_xgeneration would restrain ammonia emissions. As the vehicle specific power( VSP) can reflect the driving condition synthetically,the relationship between VSP and ammonia was analyzed when studying the influence of driving cycles on ammonia emissions. It could be concluded that when VSP Bin was greater than 0,the ammonia emissions based on CO_2 increased with the increasing of VSP Bin by using the VSP clustering method. And the VSP range corresponding to the maximum ammonia emissions based on CO_2 had a continuous positive acceleration. In conclusion,CO and NO_xhad different effects on ammonia emissions,and the acceleration,as one of the characterization parameters of driving conditions,would directly or indirectly affect the formation of ammonia by affecting CO and NO_xemissions.
In order to study the effects of the conventional pollutants and driving conditions on the ammonia emission of gasoline vehicles under the WLTC cycle,the molar emissions of CO_2,CO,NO_xand ammonia were measured on the selected vehicles which met the China-5 emission standard and were equipped with three-way catalyst( TWC). The results showed that the linear correlation coefficients of CO,NO_xand ammonia emissions were 0. 626 and 0. 321,respectively. The high emission of ammonia was accompanied not only by high CO emission,but also by high speed and continuous positive acceleration. The differences of the NO_xemission concentrations between precatalyst and post catalyst were used to express the conversion amount of NO_x. It was found that the high conversion of NO_xdidn' t necessarily correspond to the high emission of ammonia. In the later stage of the cycle,the large amount of NO_xgeneration would restrain ammonia emissions. As the vehicle specific power( VSP) can reflect the driving condition synthetically,the relationship between VSP and ammonia was analyzed when studying the influence of driving cycles on ammonia emissions. It could be concluded that when VSP Bin was greater than 0,the ammonia emissions based on CO_2 increased with the increasing of VSP Bin by using the VSP clustering method. And the VSP range corresponding to the maximum ammonia emissions based on CO_2 had a continuous positive acceleration. In conclusion,CO and NO_xhad different effects on ammonia emissions,and the acceleration,as one of the characterization parameters of driving conditions,would directly or indirectly affect the formation of ammonia by affecting CO and NO_xemissions.
引文
[1]中国环境监测总站.2018年2月京津冀、长三角、珠三角区域及直辖市、省会城市和计划单列市空气质量报告[R].北京:中国环境监测总站,2018:1-16.
[2]王跃思,姚利,刘子锐,等.京津冀大气霾污染及控制策略思考[J].中国科学院院刊,2013,28(3):353-363.
[3]张延君,郑玫,蔡靖,等.PM2. 5源解析方法的比较与评述[J].科学通报,2015,60(2):109-121.ZHANG Yanjun,ZHENG Mei,CAI Jing,et al. Comparison and overview of PM2. 5source apportionment methods[J]. Chinese Science Bulletin,2015,60(2):109-121.
[4]彭应登,张中华,胡粼粼.北京雾霾天形成的原因及特点浅析[C]//中国环境科学学会. 2013中国环境科学学会学术年会论文集(第五卷).北京:中国环境科学学会,2013:4257-4259.
[5] WANG Wenxin,WANG Shanshan,XU Jianhua,et al. Gas-phase ammonia and PM2. 5ammonium in a busy traffic area of Nanjing,China[J].Environmental Science and Pollution Research,2016,23(2):1691-1702.
[6] MENG Wenjun,ZHONG Qirui,YUN Xiao,et al.Improvement of a global high-resolution ammonia emission inventory for combustion and industrial sources with new data from the residential and transportation sectors[J]. Environmental Science&Technology,2017,51(5):2821-2829.
[7]董艳强,陈长虹,黄成,等.长江三角洲地区人为源氨排放清单及分布特征[J].环境科学学报,2009,29(8):1611-1617.DONG Yanqiang,CHEN Changhong,HUANG Cheng,et al.Anthropogenic emissions and distribution of ammonia over the Yangtze River Delta[J]. Acta Scientiae Circumstantiae,2009,29(8):1611-1617.
[8] HEEB N V,FORSS A M,STEFAN B,et al. Three-way catalystinduced formation of ammonia velocity and acceleration-dependent emission factors[J]. Atmospheric Environment,2006,40(31):5986-5997.
[9] Environmental Protection Agency(EPA). The 2007 national emissions inventory[EB/OL]. Washington DC:Environmental Protection Agency,2017[2018-04-27]. https://www. epa. gov/airemissions-inventories.
[10] BEHERA S N,SHARMA M,ANEJA V P,et al. Ammonia in the atmosphere:a review on emission sources,atmospheric chemistry and deposition on terrestrial bodies[J].Environmental Science and Pollution Research,2013,20(11):8092-8131.
[11] MATSUMOTO R,UMEZAWA N,KARAUSHI M,et al.Comparison of ammonium deposition flux at roadside and at an agricultural area for long-term monitoring:emission of ammonia from vehicles[J].Water,Air,and Soil Pollution,2006,173(4):355-371.
[12] TANNER P A. Vehicle-related ammonia emissions in Hong Kong[J].Environmental Chemistry Letters,2009,7(1):37-40.
[13] SUN Kang,TAO Lei,MILLER D J,et al. On-road ammonia emissions characterized by mobile,open-path measurements[J].Environmental Science&Technology,2014,48(7):3943-3950.
[14] HUY D H,THANH L T,HIEN T T,et al. Characteristics of ammonia gas and fine particulate ammonium from two distinct urban areas:Osaka,Japan,and Ho Chi Minh City,Vietnam[J].Environmental Science and Pollution Research,2017,24(9):8147-8163.
[15]周生贤.全力落实《大气污染防治行动计划》让人民群众享有更多蓝天白云[J].环境保护,2013,41(24):10-12.
[16] BEHERA S N,SHARMA M. Investigating the potential role of ammonia in ion chemistry of fine particulate matter formation for an urban environment[J].Science of the Total Environment,2010,408(17):3569-3575.
[17] SHELEF M,GANDHI H S. Ammonia formation in the catalytic reduction of nitric oxide:the role of water gas shift,reduction by hydrocarbons,and steam reforming[J]. Industrial and engineering chemistry,process design and development,1974,13(1):80-84.
[18] DIGIULIO C D,PIHL J A,PARKS II J E,et al.Passive-ammonia selective catalytic reduction(SCR):understanding NH3formation over close-coupled three way catalysts(TWC)[J]. Catalysis Today,2014,231:33-45.
[19] HUAI T,DURBIN T D,MILLER J W,et al. Investigation of NH3emissions from new technology vehicles as a function of vehicle operating conditions[J]. Environmental Science&Technology,2003,37(21):4841-4847.
[20] VANDERLEI B,JOO V D A. Ammonia emissions from a lightduty vehicle[J]. Transportation Research Part D:Transport and Environment,2017,51:53-61.
[21]杨俊.广州市机动车尾气中氨气的排放因子研究[D].广州:暨南大学,2011:33-34.
[22] DURBIN T D,WILSON R D,NORBECK J M,et al. Estimates of the emission rates of ammonia from light-duty vehicles using standard chassis dynamometer test cycles[J]. Atmospheric Environment,2002,36(9):1475-1482.
[23]中华人民共和国环境保护部.GB 18352. 6—2016轻型汽车污染物排放限值及测量方法(中国第六阶段)(发布稿)[S].北京:中国环境科学出版社,2016.
[24] JIMENEZ-PALACIOS J L. Understanding and quantifying motor vehicle emissions with vehicle specific power and TILDAS remote sensing[D]. Massachusetts:Department of Mechanical Engineering,Massachusetts Institute of Technology,1999:53-56.
[25]胡友波.不同模式混合动力公交车节能环保效益分析与研究[D].武汉:武汉理工大学,2009:28-33.
[26]高继东.城市机动车道路排放因子和排放特性研究[D].天津:天津大学,2009:36-37.
[27] RYKOWSKI R A,NAM E K,HOFFMAN G. On-road testing and characterization of fuel economy of light-duty vehicles[EB/OL].Detroit,Michigan:SAE International,2005[2018-04-22]. https://doi.org/10. 4271/2005-01-0677.
[28] WYATT D W,LI H,TATE J.Examining the influence of road grade on Vehicle Specific Power(VSP)and carbon dioxide(CO2)emission over a real-world driving cycle[EB/OL]. Jacksonville,Florida:SAE International,2013[2018-04-22]. https://doi. org/10. 4271/2013-01-1518.
[29] XU Yaofang,YU Lei,SONG Guohua. Improved vehicle specific power bins for light-duty vehicles in estimation of carbon dioxide emissions in Beijing[J]. Transportation Research Record,2010.doi:10. 3141/2191-20.
[30] LI Yongquan,SCHWAB J J,DEMERJIAN K L. Measurements of ambient ammonia using a tunable Diode laser absorption spectrometer:characteristics of ambient ammonia emissions in an urban area of New York City[J]. Journal of Geophysical Research Atmospheres,2006,111(10):1-11.
[31] COELHO M C,FREY H. C,ROUPHAIL N M,et al. Assessing methods for comparing emissions from gasoline and diesel light-duty vehicles based on microscale measurements[J]. Transportation Research Part D:Transport and Environment,2009,14(2):91-99.
[2]王跃思,姚利,刘子锐,等.京津冀大气霾污染及控制策略思考[J].中国科学院院刊,2013,28(3):353-363.
[3]张延君,郑玫,蔡靖,等.PM2. 5源解析方法的比较与评述[J].科学通报,2015,60(2):109-121.ZHANG Yanjun,ZHENG Mei,CAI Jing,et al. Comparison and overview of PM2. 5source apportionment methods[J]. Chinese Science Bulletin,2015,60(2):109-121.
[4]彭应登,张中华,胡粼粼.北京雾霾天形成的原因及特点浅析[C]//中国环境科学学会. 2013中国环境科学学会学术年会论文集(第五卷).北京:中国环境科学学会,2013:4257-4259.
[5] WANG Wenxin,WANG Shanshan,XU Jianhua,et al. Gas-phase ammonia and PM2. 5ammonium in a busy traffic area of Nanjing,China[J].Environmental Science and Pollution Research,2016,23(2):1691-1702.
[6] MENG Wenjun,ZHONG Qirui,YUN Xiao,et al.Improvement of a global high-resolution ammonia emission inventory for combustion and industrial sources with new data from the residential and transportation sectors[J]. Environmental Science&Technology,2017,51(5):2821-2829.
[7]董艳强,陈长虹,黄成,等.长江三角洲地区人为源氨排放清单及分布特征[J].环境科学学报,2009,29(8):1611-1617.DONG Yanqiang,CHEN Changhong,HUANG Cheng,et al.Anthropogenic emissions and distribution of ammonia over the Yangtze River Delta[J]. Acta Scientiae Circumstantiae,2009,29(8):1611-1617.
[8] HEEB N V,FORSS A M,STEFAN B,et al. Three-way catalystinduced formation of ammonia velocity and acceleration-dependent emission factors[J]. Atmospheric Environment,2006,40(31):5986-5997.
[9] Environmental Protection Agency(EPA). The 2007 national emissions inventory[EB/OL]. Washington DC:Environmental Protection Agency,2017[2018-04-27]. https://www. epa. gov/airemissions-inventories.
[10] BEHERA S N,SHARMA M,ANEJA V P,et al. Ammonia in the atmosphere:a review on emission sources,atmospheric chemistry and deposition on terrestrial bodies[J].Environmental Science and Pollution Research,2013,20(11):8092-8131.
[11] MATSUMOTO R,UMEZAWA N,KARAUSHI M,et al.Comparison of ammonium deposition flux at roadside and at an agricultural area for long-term monitoring:emission of ammonia from vehicles[J].Water,Air,and Soil Pollution,2006,173(4):355-371.
[12] TANNER P A. Vehicle-related ammonia emissions in Hong Kong[J].Environmental Chemistry Letters,2009,7(1):37-40.
[13] SUN Kang,TAO Lei,MILLER D J,et al. On-road ammonia emissions characterized by mobile,open-path measurements[J].Environmental Science&Technology,2014,48(7):3943-3950.
[14] HUY D H,THANH L T,HIEN T T,et al. Characteristics of ammonia gas and fine particulate ammonium from two distinct urban areas:Osaka,Japan,and Ho Chi Minh City,Vietnam[J].Environmental Science and Pollution Research,2017,24(9):8147-8163.
[15]周生贤.全力落实《大气污染防治行动计划》让人民群众享有更多蓝天白云[J].环境保护,2013,41(24):10-12.
[16] BEHERA S N,SHARMA M. Investigating the potential role of ammonia in ion chemistry of fine particulate matter formation for an urban environment[J].Science of the Total Environment,2010,408(17):3569-3575.
[17] SHELEF M,GANDHI H S. Ammonia formation in the catalytic reduction of nitric oxide:the role of water gas shift,reduction by hydrocarbons,and steam reforming[J]. Industrial and engineering chemistry,process design and development,1974,13(1):80-84.
[18] DIGIULIO C D,PIHL J A,PARKS II J E,et al.Passive-ammonia selective catalytic reduction(SCR):understanding NH3formation over close-coupled three way catalysts(TWC)[J]. Catalysis Today,2014,231:33-45.
[19] HUAI T,DURBIN T D,MILLER J W,et al. Investigation of NH3emissions from new technology vehicles as a function of vehicle operating conditions[J]. Environmental Science&Technology,2003,37(21):4841-4847.
[20] VANDERLEI B,JOO V D A. Ammonia emissions from a lightduty vehicle[J]. Transportation Research Part D:Transport and Environment,2017,51:53-61.
[21]杨俊.广州市机动车尾气中氨气的排放因子研究[D].广州:暨南大学,2011:33-34.
[22] DURBIN T D,WILSON R D,NORBECK J M,et al. Estimates of the emission rates of ammonia from light-duty vehicles using standard chassis dynamometer test cycles[J]. Atmospheric Environment,2002,36(9):1475-1482.
[23]中华人民共和国环境保护部.GB 18352. 6—2016轻型汽车污染物排放限值及测量方法(中国第六阶段)(发布稿)[S].北京:中国环境科学出版社,2016.
[24] JIMENEZ-PALACIOS J L. Understanding and quantifying motor vehicle emissions with vehicle specific power and TILDAS remote sensing[D]. Massachusetts:Department of Mechanical Engineering,Massachusetts Institute of Technology,1999:53-56.
[25]胡友波.不同模式混合动力公交车节能环保效益分析与研究[D].武汉:武汉理工大学,2009:28-33.
[26]高继东.城市机动车道路排放因子和排放特性研究[D].天津:天津大学,2009:36-37.
[27] RYKOWSKI R A,NAM E K,HOFFMAN G. On-road testing and characterization of fuel economy of light-duty vehicles[EB/OL].Detroit,Michigan:SAE International,2005[2018-04-22]. https://doi.org/10. 4271/2005-01-0677.
[28] WYATT D W,LI H,TATE J.Examining the influence of road grade on Vehicle Specific Power(VSP)and carbon dioxide(CO2)emission over a real-world driving cycle[EB/OL]. Jacksonville,Florida:SAE International,2013[2018-04-22]. https://doi. org/10. 4271/2013-01-1518.
[29] XU Yaofang,YU Lei,SONG Guohua. Improved vehicle specific power bins for light-duty vehicles in estimation of carbon dioxide emissions in Beijing[J]. Transportation Research Record,2010.doi:10. 3141/2191-20.
[30] LI Yongquan,SCHWAB J J,DEMERJIAN K L. Measurements of ambient ammonia using a tunable Diode laser absorption spectrometer:characteristics of ambient ammonia emissions in an urban area of New York City[J]. Journal of Geophysical Research Atmospheres,2006,111(10):1-11.
[31] COELHO M C,FREY H. C,ROUPHAIL N M,et al. Assessing methods for comparing emissions from gasoline and diesel light-duty vehicles based on microscale measurements[J]. Transportation Research Part D:Transport and Environment,2009,14(2):91-99.