典型烟煤中游离态母体及烷基多环芳烃的含量和组成特征
|
摘要
民用燃煤是我国最重要的多环芳烃(PAHs)和黑碳(BC)排放源,但排放因子明显受控于煤的地质成熟度,可能与煤中游离态PAHs的含量和组成相关。本研究选择6种不同成熟度的烟煤(干燥无灰基挥发分含量V_(daf)为19.4%~48.3%),以二氯甲烷为溶剂进行索氏抽提获得煤中游离态PAHs,通过气相色谱-质谱联用仪(GC-MS)进行分析检测,获得16种优控母体PAHs(pPAHs)和16种烷基PAHs(aPAHs)的含量和组成特征,并探讨PAHs的含量和组成及与煤成熟度的关系,为研究民用燃煤PAHs和BC的生成机理提供支持。结果表明:(1)6种烟煤中PAHs的总含量为39.8~289.0 mg/kg,中等挥发分烟煤(V_(daf)为25.6%~35.5%)明显高于高挥发分和低挥发分烟煤,不同烟煤之差可达7倍,这与民用燃煤排放PAHs和BC的情况相似;(2)6种烟煤中pPAHs的含量范围为8.3~58.4 mg/kg,在V_(daf)为25.6%~30.5%时最高;aPAHs的含量为31.4~236.5 mg/kg,在V_(daf)为25.6%和35.5%时呈双峰分布;aPAHs含量平均比pPAHs高4倍,这种趋势以及PAHs含量范围与煤烟成分基本一致的情况,说明民用燃烧条件下煤烟成分对原煤游离态PAHs有较好的继承;(3)组成方面:pPAHs在V_(daf)为25.6%以下时以低环(2~3环)为主,而在V_(daf)高于30%时以中高环(4~6环)为主;aPAHs的情况相似,即中高成熟度烟煤以低环为主,而4环aPAHs在V_(daf)为30.5%~35.5%最高;PAHs组成上的这种变化趋势很好地反映了煤化学结构随成熟度演变的规律,也能较好地解释中等挥发分烟煤PAHs和BC排放因子最高的现象。
Residential coal combustion(RCC) is the most important emission source of polycyclic aromatic hydrocarbons(PAHs) and black carbon(BC) in China. Their emission factors are obviously controlled by the geological maturity of coals, therefore they may be related with the concentration and composition of soluble PAHs in coals. Six types of bituminous coal differing in maturity were selected in this study to determine soluble PAHs by GC/MS after Soxhlet extraction with DCM solvent. Through analyzing 16 parent PAHs(pPAHs) and 16 alkylated PAHs(aPAHs), the paper discussed the relationship between the concentration and composition of PAHs and coal maturity. Moreover, it may be helpful to study the formation mechanism of PAHs and BC during RCC. The results show that:(1) the total PAH concentrations in the six tested coal types are within the range of 39.8~289.0 mg/kg, and the coals with a medium volatile material content on the dry and ash-free basis(V_(daf)) have higher PAHs than those V_(daf) bituminous coals with high and low volatile material contents. Various coals show a difference by seven times, which is similar to the trend of emission factors of PAHs and BC of RCC;(2) pPAHs concentrations are winthin the range of 8.3~58.4 mg/kg in the six coal types, with the highest value occurring in those coals with a V_(daf) range of 25.6%~30.5%. Their aPAHs are within the range of 31.4~236.5 mg/kg, with two peaks existing at V_(daf) values within the range of 25.6% and 35.5%, respectively; the concentrations of aPAHs are higher than those of pPAHs by four times on average. The similar ranges of PAHs concentrations in both raw coals and RCC smoke as well as higher alkylated PAHs than pPAHs, may illustrate the succession of PAHs in coal smoke from soluble compounds;(3) as for the composition, low-ringed compounds(2~3 rings) are dominated by pPAHs in coals with V_(daf) less than 25.6%, while middle-to high-ringed PAHs(4~6 rings) have dominatedly the concentrations at V_(daf) over 30%; the case is similar for aPAHs with respect to this similarity, in which 2~3-ringed compounds are the main part in bituminous coals with middle to high maturities, while 4-ringed compounds have the highest concentrations at V_(daf) of 30.5%~35.5%. This compositional trend of soluble PAHs reflects the evolution rule of geological maturity of coal chemical structure y, and it also explains, to some extent, the phenomenon of the highest emission factors of PAHs and BC for middle volatile bituminous coals during RCC.
Residential coal combustion(RCC) is the most important emission source of polycyclic aromatic hydrocarbons(PAHs) and black carbon(BC) in China. Their emission factors are obviously controlled by the geological maturity of coals, therefore they may be related with the concentration and composition of soluble PAHs in coals. Six types of bituminous coal differing in maturity were selected in this study to determine soluble PAHs by GC/MS after Soxhlet extraction with DCM solvent. Through analyzing 16 parent PAHs(pPAHs) and 16 alkylated PAHs(aPAHs), the paper discussed the relationship between the concentration and composition of PAHs and coal maturity. Moreover, it may be helpful to study the formation mechanism of PAHs and BC during RCC. The results show that:(1) the total PAH concentrations in the six tested coal types are within the range of 39.8~289.0 mg/kg, and the coals with a medium volatile material content on the dry and ash-free basis(V_(daf)) have higher PAHs than those V_(daf) bituminous coals with high and low volatile material contents. Various coals show a difference by seven times, which is similar to the trend of emission factors of PAHs and BC of RCC;(2) pPAHs concentrations are winthin the range of 8.3~58.4 mg/kg in the six coal types, with the highest value occurring in those coals with a V_(daf) range of 25.6%~30.5%. Their aPAHs are within the range of 31.4~236.5 mg/kg, with two peaks existing at V_(daf) values within the range of 25.6% and 35.5%, respectively; the concentrations of aPAHs are higher than those of pPAHs by four times on average. The similar ranges of PAHs concentrations in both raw coals and RCC smoke as well as higher alkylated PAHs than pPAHs, may illustrate the succession of PAHs in coal smoke from soluble compounds;(3) as for the composition, low-ringed compounds(2~3 rings) are dominated by pPAHs in coals with V_(daf) less than 25.6%, while middle-to high-ringed PAHs(4~6 rings) have dominatedly the concentrations at V_(daf) over 30%; the case is similar for aPAHs with respect to this similarity, in which 2~3-ringed compounds are the main part in bituminous coals with middle to high maturities, while 4-ringed compounds have the highest concentrations at V_(daf) of 30.5%~35.5%. This compositional trend of soluble PAHs reflects the evolution rule of geological maturity of coal chemical structure y, and it also explains, to some extent, the phenomenon of the highest emission factors of PAHs and BC for middle volatile bituminous coals during RCC.
引文
[1]Wang R,Tao S,Wang W T,Liu J F,Shen H Z,Shen G F,Wang B,Liu X P,Li W,Huang Y,Zhang Y Y,Lu Y,Chen H,Chen Y C,Wang C,Zhu D,Wang X L,Li B G,Liu W X,Ma J M.Black carbon emissions in China from 1949 to 2050[J].Environ Sci Tech,2012,46(14):7595–7603.
[2]Zhang Y X,Tao S,Cao J,Coveney R M Jr.Emission of polycyclic aromatic hydrocarbons in China by county[J].Environ Sci Tech,2007,41(3):683–687.
[3]Archer-Nicholls S,Carter E,Kumar R,Xiao Q,Liu Y,Frostad J,Forouzanfar M H,Cohen A,Brauer M,Baumgartner J,Wiedinmyer C.The regional impacts of cooking and heating emissions on ambient air quality and disease burden in China[J].Environ Sci Tech,2016,50(17):9416–9423.
[4]Shao L Y,Hu Y,Wang J,Hou C,Yang Y Y,Wu M Y.Particle-induced oxidative damage of indoor PM10 from coal burning homes in the lung cancer area of Xuan Wei,China[J].Atmos Environ,2013,77:959–967.
[5]Ren A G,Qiu X H,Jin L,Ma J,Li Z W,Zhang L,Zhu H P,Finnell R H,Zhu T.Association of selected persistent organic pollutants in the placenta with the risk of neural tube defects[J].Proc Natl Acad Sci USA,2011,108(31):12770–12775.
[6]Liu J,Mauzerall D L,Chen Q,Zhang Q,Song Y,Peng W,Klimont Z,Qiu X,Zhang S,Hu M,Lin W,Smith K R,Zhu T.Air pollutant emissions from Chinese households:A major and underappreciated ambient pollution source[J].Proc Natl Acad Sci USA,2016,113(28):7756–7761.
[7]陈颖军,姜晓华,支国瑞,冯艳丽,盛国英,傅家谟.我国民用燃煤的黑碳排放及控制减排[J].中国科学(D辑),2009,39(11):1554–1559.Chen Yingjun,Jiang Xiaohua,Zhi Guorui,Feng Yanli,Sheng Guoying,Fu Jiamo.Black carbon emissions from residential coal combustion and reduction strategy[J].Sci China(D),2009,39(11):1554–1559(in Chinese).
[8]Chen Y J,Zhi G R,Feng Y L,Tian C G,Bi X H,Li J,Zhang G.Increase in polycyclic aromatic hydrocarbon(PAH)emissions due to briquetting:A challenge to the coal briquetting policy[J].Environ Pollut,2015,204:58–63.
[9]陈颖军.家用蜂窝煤燃烧烟气中碳颗粒物和多换芳烃的排放特征[D].广州:中国科学院广州地球化学研究所,2004.Chen Ying-jun.Emission characteristics of carbonaceous particulate and polycyclic aromatic hydrocarbons from residential honeycomb-coal-briquette combustion[D].Guangzhou:Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,2004(in Chinese with English abstract).
[10]Zhao Z B,Liu K L,Xie W,Pan W P,Riley J T.Soluble polycyclic aromatic hydrocarbons in raw coals[J].J Hazard Mater,2000,73(1):77–85.
[11]Xue J,Liu G J,Niu Z Y,Chou C L,Qi C C,Zheng L G,Zhang H Y.Factors that influence the extraction of polycyclic aromatic hydrocarbons from coal[J].Energ Fuel,2007,21(2):881–890.
[12]Stout S A,Emsbo-Mattingly S D.Concentration and character of PAHs and other hydrocarbons in coals of varying rank—Implications for environmental studies of soils and sediments containing particulate coal[J].Org Geochem,2008,39(7):801–819.
[13]Wang R W,Liu G J,Zhang J M,Chou C L,Liu J J.Abundances of polycyclic aromatic hydrocarbons(PAHs)in 14Chinese and American coals and their relation to coal rank and weathering[J].Energ Fuel,2010,24:6061–6066.
[14]陈颖军,冯艳丽,支国瑞,盛国英,傅家谟.民用煤室内燃烧条件下多环芳烃的排放特征[J].地球化学,2007,36(1):49–54.Chen Ying-jun,Feng Yan-li,Zhi Guo-rui,Sheng Guo-ying,Fu Jia-mo.Charteristics of polycyclic aromatic emitted from indoor combution of domestic coals[J].Geochimica,2007,36(1):49–54(in Chinese with English abstract).
[15]海婷婷,陈颖军,王艳,田崇国,林田.民用燃煤烟气中甲基多环芳烃的排放特征[J].中国环境科学,2013,33(6):979–984.Hai Ting-ting,Chen Ying-jun,Wang Yan,Tian Chong-guo,Lin Tian.Characteristics of alkyl-PAHs emitted from combustion of domestic coals[J].China Environ Sci,2013,33(6):979–984(in Chinese with English abstract).
[16]董洁.煤热解过程中PAHs的形成及其催化裂解特性[D].太原:太原理工大学,2013.Dong Jie.PAHs formation and its catalytic cracking property during coal pyrolysis[D].Taiyuan:Taiyuan University of Technology,2013(in Chinese with English abstract).
[17]Wang R W,Liu G J.Variations of concentration and composition of polycyclic aromatic hydrocarbons in coals in response to dike intrusion in the Huainan coalfield in eastern China[J].Org Geochem,2015,83/84:202–214.
[18]Walgraeve C,Demeestere K,Dewulf J,Zimmermann R,Van Langenhove H V.Oxygenated polycyclic aromatic hydrocarbons in atmospheric particulate matter:Molecular characterization and occurrence[J].Atmos Environ,2010,44(15):1831–1846.
[19]Chen Y J,Sheng G Y,Bi X H,Feng Y L,Mai B X,Fu J M.Emission factors for carbonaceous particles and polycyclic aromatic hydrocarbons from residential coal combustion in China[J].Environ Sci Tech,2005,39(6):1861–1867.
[20]海婷婷,陈颖军,王艳,田崇国,林田.民用燃煤源中多环芳烃排放因子实测及其影响因素研究[J].环境科学,2013,34(7):2533–2538.Hai Ting-ting,Chen Ying-jun,Wang Yan,Tian Chong-guo,Lin Tian.Emission factors of polycyclic aromatic hydrocarbons(PAHs)in residentialcoal combustion and its influence factors[J].Environ Sci,2013,34(7):2533–2538(in Chinese with English abstract).
[21]叶翠平.煤大分子化合物结构测定及模型构建[D].太原:太原理工大学,2008.Ye Cui-ping.Characterization and modeling of coal high molecular weight components[D].Taiyuan:Taiyuan University of Technology,2008(in Chinese with English abstract).
[22]Chen Y J,Tian C G,Feng Y L,Zhi G R,Li J,Zhang G.Measurements of emission factors of PM2.5,OC,EC,and BC for household stoves of coal combustion in China[J].Atmos Environ,2015,109:190–196.
[23]沈国锋.室内固体燃料燃烧产生的碳颗粒物和多环芳烃的排放因子及影响因素[D].北京:北京大学,2012.Shen Guo-feng.Emission factors of carbonaceous particulate matter and polycyclic aromatic hydrocarbons from residential solid fuel combustions[D].Beijing:Peking University,2012(in Chinese with English abstract).
[2]Zhang Y X,Tao S,Cao J,Coveney R M Jr.Emission of polycyclic aromatic hydrocarbons in China by county[J].Environ Sci Tech,2007,41(3):683–687.
[3]Archer-Nicholls S,Carter E,Kumar R,Xiao Q,Liu Y,Frostad J,Forouzanfar M H,Cohen A,Brauer M,Baumgartner J,Wiedinmyer C.The regional impacts of cooking and heating emissions on ambient air quality and disease burden in China[J].Environ Sci Tech,2016,50(17):9416–9423.
[4]Shao L Y,Hu Y,Wang J,Hou C,Yang Y Y,Wu M Y.Particle-induced oxidative damage of indoor PM10 from coal burning homes in the lung cancer area of Xuan Wei,China[J].Atmos Environ,2013,77:959–967.
[5]Ren A G,Qiu X H,Jin L,Ma J,Li Z W,Zhang L,Zhu H P,Finnell R H,Zhu T.Association of selected persistent organic pollutants in the placenta with the risk of neural tube defects[J].Proc Natl Acad Sci USA,2011,108(31):12770–12775.
[6]Liu J,Mauzerall D L,Chen Q,Zhang Q,Song Y,Peng W,Klimont Z,Qiu X,Zhang S,Hu M,Lin W,Smith K R,Zhu T.Air pollutant emissions from Chinese households:A major and underappreciated ambient pollution source[J].Proc Natl Acad Sci USA,2016,113(28):7756–7761.
[7]陈颖军,姜晓华,支国瑞,冯艳丽,盛国英,傅家谟.我国民用燃煤的黑碳排放及控制减排[J].中国科学(D辑),2009,39(11):1554–1559.Chen Yingjun,Jiang Xiaohua,Zhi Guorui,Feng Yanli,Sheng Guoying,Fu Jiamo.Black carbon emissions from residential coal combustion and reduction strategy[J].Sci China(D),2009,39(11):1554–1559(in Chinese).
[8]Chen Y J,Zhi G R,Feng Y L,Tian C G,Bi X H,Li J,Zhang G.Increase in polycyclic aromatic hydrocarbon(PAH)emissions due to briquetting:A challenge to the coal briquetting policy[J].Environ Pollut,2015,204:58–63.
[9]陈颖军.家用蜂窝煤燃烧烟气中碳颗粒物和多换芳烃的排放特征[D].广州:中国科学院广州地球化学研究所,2004.Chen Ying-jun.Emission characteristics of carbonaceous particulate and polycyclic aromatic hydrocarbons from residential honeycomb-coal-briquette combustion[D].Guangzhou:Guangzhou Institute of Geochemistry,Chinese Academy of Sciences,2004(in Chinese with English abstract).
[10]Zhao Z B,Liu K L,Xie W,Pan W P,Riley J T.Soluble polycyclic aromatic hydrocarbons in raw coals[J].J Hazard Mater,2000,73(1):77–85.
[11]Xue J,Liu G J,Niu Z Y,Chou C L,Qi C C,Zheng L G,Zhang H Y.Factors that influence the extraction of polycyclic aromatic hydrocarbons from coal[J].Energ Fuel,2007,21(2):881–890.
[12]Stout S A,Emsbo-Mattingly S D.Concentration and character of PAHs and other hydrocarbons in coals of varying rank—Implications for environmental studies of soils and sediments containing particulate coal[J].Org Geochem,2008,39(7):801–819.
[13]Wang R W,Liu G J,Zhang J M,Chou C L,Liu J J.Abundances of polycyclic aromatic hydrocarbons(PAHs)in 14Chinese and American coals and their relation to coal rank and weathering[J].Energ Fuel,2010,24:6061–6066.
[14]陈颖军,冯艳丽,支国瑞,盛国英,傅家谟.民用煤室内燃烧条件下多环芳烃的排放特征[J].地球化学,2007,36(1):49–54.Chen Ying-jun,Feng Yan-li,Zhi Guo-rui,Sheng Guo-ying,Fu Jia-mo.Charteristics of polycyclic aromatic emitted from indoor combution of domestic coals[J].Geochimica,2007,36(1):49–54(in Chinese with English abstract).
[15]海婷婷,陈颖军,王艳,田崇国,林田.民用燃煤烟气中甲基多环芳烃的排放特征[J].中国环境科学,2013,33(6):979–984.Hai Ting-ting,Chen Ying-jun,Wang Yan,Tian Chong-guo,Lin Tian.Characteristics of alkyl-PAHs emitted from combustion of domestic coals[J].China Environ Sci,2013,33(6):979–984(in Chinese with English abstract).
[16]董洁.煤热解过程中PAHs的形成及其催化裂解特性[D].太原:太原理工大学,2013.Dong Jie.PAHs formation and its catalytic cracking property during coal pyrolysis[D].Taiyuan:Taiyuan University of Technology,2013(in Chinese with English abstract).
[17]Wang R W,Liu G J.Variations of concentration and composition of polycyclic aromatic hydrocarbons in coals in response to dike intrusion in the Huainan coalfield in eastern China[J].Org Geochem,2015,83/84:202–214.
[18]Walgraeve C,Demeestere K,Dewulf J,Zimmermann R,Van Langenhove H V.Oxygenated polycyclic aromatic hydrocarbons in atmospheric particulate matter:Molecular characterization and occurrence[J].Atmos Environ,2010,44(15):1831–1846.
[19]Chen Y J,Sheng G Y,Bi X H,Feng Y L,Mai B X,Fu J M.Emission factors for carbonaceous particles and polycyclic aromatic hydrocarbons from residential coal combustion in China[J].Environ Sci Tech,2005,39(6):1861–1867.
[20]海婷婷,陈颖军,王艳,田崇国,林田.民用燃煤源中多环芳烃排放因子实测及其影响因素研究[J].环境科学,2013,34(7):2533–2538.Hai Ting-ting,Chen Ying-jun,Wang Yan,Tian Chong-guo,Lin Tian.Emission factors of polycyclic aromatic hydrocarbons(PAHs)in residentialcoal combustion and its influence factors[J].Environ Sci,2013,34(7):2533–2538(in Chinese with English abstract).
[21]叶翠平.煤大分子化合物结构测定及模型构建[D].太原:太原理工大学,2008.Ye Cui-ping.Characterization and modeling of coal high molecular weight components[D].Taiyuan:Taiyuan University of Technology,2008(in Chinese with English abstract).
[22]Chen Y J,Tian C G,Feng Y L,Zhi G R,Li J,Zhang G.Measurements of emission factors of PM2.5,OC,EC,and BC for household stoves of coal combustion in China[J].Atmos Environ,2015,109:190–196.
[23]沈国锋.室内固体燃料燃烧产生的碳颗粒物和多环芳烃的排放因子及影响因素[D].北京:北京大学,2012.Shen Guo-feng.Emission factors of carbonaceous particulate matter and polycyclic aromatic hydrocarbons from residential solid fuel combustions[D].Beijing:Peking University,2012(in Chinese with English abstract).