-
多环芳烃(polycyclic aromatic hydrocarbons,以下简称PAHs)对人体具有强烈的致癌、致畸、致突变效应,且在环境中广泛存在 [1-3]。燃煤电厂是环境中大气污染物的重要来源[4-5]。我国燃煤电厂广泛配备的脱硝、除尘和脱硫设施虽然可以高效去除NOx、SO2、粉尘等常规大气污染物,却难以去除更容易进入人体肺部的可过滤细颗粒物、可凝结颗粒物和气态PAHs[6-8]。
近年来,燃煤电厂大气污染物的排放因子和排放清单成为大气污染防治领域的研究热点,并且在识别燃煤电厂大气污染物排放特征、时空分布、以及区域环境效应等方面取得重要进展[9-13]。燃煤电厂排放PAHs的研究主要关注燃煤产物中PAHs的含量、分布和赋存状态的分析,以及燃煤锅炉烟气排放过程PAHs的赋存规律及影响因素等方面[13-19],而关于燃煤电厂PAHs的排放因子和清单的研究较少,尤其缺乏不同燃煤锅炉大气PAHs的精细化排放因子以及其历史排放通量的基础数据。基于此,本研究以安徽省为例,结合资料收集、实地调研和现场实测数据,“自下而上”构建了安徽燃煤电厂大气PAHs的历史排放清单,以查明锅炉、机组、大气污染控制设施以及超低排放改造对安徽燃煤电厂PAHs历史排放量的贡献值。
安徽燃煤电厂多环芳烃的历史排放量及影响因素分析
The historical emissions of polycyclic aromatic hydrocarbons (PAHs) from coal-fired power plants in Anhui and influencing factors
-
摘要: 自2010年,中国燃煤电厂大范围普及的大气污染物净化设备极大地改变了多环芳烃(PAHs)的排放格局。本研究以中国煤炭重要产地安徽为例,建立自下而上的PAHs历史排放清单,分析2010年到2017年间PAHs的排放规模、强度和特征的变化。2017年煤粉炉和循环流化床锅炉的PAHs排放总量近似,分别为8600 kg和7800 kg。细分至不同城市,PAHs排放量最大的城市分别为淮南(3600 kg),淮北(3100 kg),马鞍山(1800 kg)。不同锅炉类型的年均排放速率和排放强度产生极大的差异,循环流化床炉的年均排放速率和排放强度(7.2 kg·t−1和2.1 kg·MW-1)分别是煤粉炉(1.1 kg·t-1和0.19 kg·MW−1)的7倍和11倍。这主要是由于循环流化床的较低燃烧温度和不完全的燃烧条件所导致。PAHs排放量的时间尺度变化也较为显著,在2012年至2017年间,随着燃煤电厂对小锅炉的关闭和大气污染净化设备的革新升级,单位锅炉的PAHs排放强度不断降低。此外,PAHs的排放格局还受到气温变化的影响,在相对较热的夏季和较冷的冬季,过度使用空调也会造成电力的额外消耗,增加区域PAHs的排放强度。Abstract: The polycyclic aromatic hydrocarbon (PAH) emissions have changed dramatically since the great change of infrastructures of Chinese coal-fired power plants (CFPPs) after 2010. The current study aims to construct a unit-based PAH emission inventory for CFPPs in Anhui province, which is one of the most important coal habitat in China, to characterize the PAH emissions from CFPPs between 2010 to 2017. The total atmospheric PAH emissions from pulverized coal (PC) and circulating fluidized bed (CFB) in 2017 were 8600 kg and 7800 kg, respectively. At civic level, Huainan, Huaibei, and Ma’Anshan ranked the top three cities in 2017, with total PAH emissions at 3650 kg, 3100 kg, and 1800 kg, respectively. The emission rates and intensities for CFB units (7.2 kg·t−1 and 2.1 kg·MW−1) were ca. 7 and 11 times higher than those for PC units (1.1 kg·t−1 and 0.19 kg·MW−1). The decreased PAH emissions from CFPPs between 2012 and 2017 was attributed to the accomplishment of ultralow emission technologies and phase-out of outdated coal-fired units. The increased PAH emissions in 2013 and 2017, when there were a warmer summer and colder winter, respectively, compared to other years, may resulted from increased coal consumption of the CFPPs accompanied by the electricity consumption for cooling or heating.
-
图 5 2010—2017年PAHs年排放量(PAHs)、居民用电量(RE)、城市用电量(UE)、工业用电量(IE)、高温值(EHT)、低温值(ELT)的lg值变化
Figure 5. The logarithmic values of PAH emissions (PAHs), resident electricity consumption (RE), urban electricity consumption (UE), industry-wide electricity consumption (IE), extreme high temperature (EHT), and extreme low temperature (ELT) from 2010 to 2017 in Anhui
表 1 典型燃煤锅炉现场试验的基本信息
Table 1. Basic information of the six coal-fired units in field tests
锅炉
Boiler城市
City机组容量/
MW
Capacity燃煤类型
Coal typeaAPCDb 燃煤效率/(t·h−1)
Combustion efficiency烟气流速/
(m·s−1)
Velocity of flue gas样本
SamplescPAHs数量
Number of PAHs煤粉炉1 淮南 600 BC SCR+WFGD+ESP 95.8 9.3 P+G 16 煤粉炉2 淮南 300 BC SCR+WFGD+ESP 37.8 10.4 P+G 16 煤粉炉3 淮南 60 BC SCR+WFGD+ESP 18.7 8.7 P+G 16 流化床炉1 淮南 300 BC, CG或IC SNCR+IFSC+FF 53.6 9.8 P+G 16 流化床炉2 淮北 15 BC, CG或IC SNCR+WFGD+FF 25.2 8.3 P+G 16 流化床炉3 淮北 15 BC, CG或IC SNCR+ISFC+FF 9.1 9.7 P+G 16 注:a, BC:烟煤,CG:煤矸石,IC:低质煤;b, SCR:选择性催化还原脱硝,SNCR:非选择性催化还原脱硝,WFGD:湿式脱硫,IFSC:炉内喷钙脱硫,ESP:静电除尘,FF:袋式除尘;c, P:颗粒相,G:气相.
Note: a, BC: bituminous coal, CG: coal gangue, IC: inferior coal; b, SCR: selective catalytic reduction, SNCR: selective non-catalytic reduction, WFGD: wet flue gas desulfurization, IFSC: in-furnace spraying calcium, ESP: electrostatic precipitator, FF: fabric filter; P: particulate, G: gaseous.表 2 锅炉机组基本信息和PAHs排放量、排放率、排放强度
Table 2. Basic information and PAH emissions, emission rates, and emission intensities from different coal-fired units
锅炉Boiler 煤炭消耗量
(×104) /t
Coal
consumptions总装机容量/
MW
Totalcapacities脱氮装置
Denitrification
device脱硫装置
Desulphurization
device除尘装置
De-dust
devicePAHs排
放因子/
(μg·kg−1)
PAHemission
factorsPAHs
排放量/
kg
PAH emission
amountPAHs
排放率/
(kg·t−1)
PAH
emission
ratesPAHs
排放强度/
(kg·MW−1)
PAH emission
intensities煤粉炉1 6120 35,340 SCR WFGD ESPs 75 4600 0.75 0.13 煤粉炉2 1220 7780 SCR WFGD ESPs 210 2550 2.1 0.32 煤粉炉3 350 1064 SCR WFGD ESPs或FFs 420 1450 4.1 1.4 流化床炉1 620 2808 SCR或SNCR IFSC ESPs或FFs 620 3800 6.1 1.4 流化床炉2 250 487 SCR或SNCR WFGD ESPs或FFs 740 1850 7.4 3.8 流化床炉3 190 300 SCR或SNCR IFSC ESPs或FFs 1150 2150 11.3 7.2 -
[1] 张玉洁, 云洋. 环境中的氧化多环芳烃综述 [J]. 环境化学, 2021, 40(1): 150-163. doi: 10.7524/j.issn.0254-6108.2020022802 ZHANG Y J, YUN Y. Oxygenated polycyclic aromatic hydrocarbons in the environment: A review [J]. Environmental Chemistry, 2021, 40(1): 150-163(in Chinese). doi: 10.7524/j.issn.0254-6108.2020022802
[2] 马涛, 孔继婕, 韩孟书, 等. 环境中硝基多环芳烃的污染现状及其毒性效应研究进展 [J]. 环境化学, 2020, 39(9): 2430-2440. doi: 10.7524/j.issn.0254-6108.2019062907 MA T, KONG J J, HAN M S, et al. Review on the pollution status and toxicity effects of nitrated polycyclic aromatic hydrocarbons in the environment [J]. Environmental Chemistry, 2020, 39(9): 2430-2440(in Chinese). doi: 10.7524/j.issn.0254-6108.2019062907
[3] 李杏茹, 白羽, 陈曦, 等. 北京冬季重污染过程大气细颗粒物化学组成特征及来源分析 [J]. 环境化学, 2018, 37(11): 2397-2409. doi: 10.7524/j.issn.0254-6108.2018011401 LI X R, BAI Y, CHEN X, et al. Chemical composition and source apportionment of PM2.5 during winter in Beijing [J]. Environmental Chemistry, 2018, 37(11): 2397-2409(in Chinese). doi: 10.7524/j.issn.0254-6108.2018011401
[4] 张晗, 刘凯, 邹天森, 等. 某地区两个燃煤电厂周边农田土壤中多环芳烃污染特征及生态安全评价 [J]. 环境化学, 2019, 38(8): 1832-1841. doi: 10.7524/j.issn.0254-6108.2018090401 ZHANG H, LIU K, ZOU T S, et al. Pollution characteristics and evaluation ecological safety of the polycyclic aromatic hydrocarbons(PAHs) pollution in surface soil of farmland around two coal-fired power plants [J]. Environmental Chemistry, 2019, 38(8): 1832-1841(in Chinese). doi: 10.7524/j.issn.0254-6108.2018090401
[5] LIU W, WU B B, BAI X X, et al. Migration and emission characteristics of ammonia/ammonium through flue gas cleaning devices in coal-fired power plants of China [J]. Environmental Science & Technology, 2020, 54(1): 390-399. [6] WANG R W, LIU G J, ZHANG J M. Variations of emission characterization of PAHs emitted from different utility boilers of coal-fired power plants and risk assessment related to atmospheric PAHs [J]. Science of the Total Environment, 2015, 538: 180-190. doi: 10.1016/j.scitotenv.2015.08.043 [7] WU B B, TIAN H Z, HAO Y, et al. Effects of wet flue gas desulfurization and wet electrostatic precipitators on emission characteristics of particulate matter and its ionic compositions from four 300 MW level ultralow coal-fired power plants [J]. Environmental Science & Technology, 2018, 52(23): 14015-14026. [8] LIU J, WANG T, CHENG J, et al. Distribution of organic compounds in coal-fired power plant emissions [J]. Energy & Fuels, 2019, 33(6): 5430-5437. [9] TONG D, ZHANG Q, LIU F, et al. Current emissions and future mitigation pathways of coal-fired power plants in China from 2010 to 2030 [J]. Environmental Science & Technology, 2018, 52(21): 12905-12914. [10] TONG D, ZHANG Q, DAVIS S J, et al. Targeted emission reductions from global super-polluting power plant units [J]. Nature Sustainability, 2018, 1(1): 59-68. doi: 10.1038/s41893-017-0003-y [11] ZHOU S L, WEI W D, CHEN L, et al. Impact of a coal-fired power plant shutdown campaign on heavy metal emissions in China [J]. Environmental Science & Technology, 2019, 53(23): 14063-14069. [12] WANG G, DENG J G, ZHANG Y, et al. Air pollutant emissions from coal-fired power plants in China over the past two decades [J]. Science of the Total Environment, 2020, 741: 140326. doi: 10.1016/j.scitotenv.2020.140326 [13] WANG R W, ZHANG J M, LIU J J, et al. Levels and patterns of polycyclic aromatic hydrocarbons in coal-fired power plant bottom ash and fly ash from Huainan, China [J]. Archives of Environmental Contamination and Toxicology, 2013, 65(2): 193-202. doi: 10.1007/s00244-013-9902-8 [14] 杨艳蓉, 周雪明, 秦娟娟, 等. 燃煤锅炉颗粒物化学组成排放特征 [J]. 环境科学, 2019, 40(9): 3908-3915. YANG Y R, ZHOU X M, QIN J J, et al. Emission characteristics of chemical composition of particulate matter from coal-fired boilers [J]. Environmental Science, 2019, 40(9): 3908-3915(in Chinese).
[15] 陈自祥, 王儒威, 孙若愚, 等. 淮南燃煤电厂汞分配、富集与释放通量 [J]. 环境化学, 2018, 37(2): 193-199. CHEN Z X, WANG R W, SUN R Y, et al. Distribution and enrichment of mercury in utility boiler of Huainan coal-fired power plant [J]. Environmental Chemistry, 2018, 37(2): 193-199(in Chinese).
[16] 倪秀峰, 王儒威, 蔡飞旋, 等. 燃煤电厂和垃圾焚烧电厂燃烧产物中卤代多环芳烃的赋存特征和毒性风险 [J]. 环境科学, 2021, 42(4): 1660-1667. NI X F, WANG R W, CAI F X, et al. Emission characteristics and toxicity effects of halogenated polycyclic aromatic hydrocarbons from coal-fired and waste incineration power plants [J]. Environmental Science, 2021, 42(4): 1660-1667(in Chinese).
[17] 袁晶晶, 笪春年, 王儒威, 等. 淮南燃煤电厂烟气中颗粒相和气相中多环芳烃的赋存特征 [J]. 环境化学, 2018, 37(6): 1382-1390. doi: 10.7524/j.issn.0254-6108.2017090201 YUAN J J, DA C N, WANG R W, et al. Occurence of polycyclic aromatic hydrocarbons in PM10-and gaseous phases of flue gases emitted from Huainan coal-fired power plant [J]. Environmental Chemistry, 2018, 37(6): 1382-1390(in Chinese). doi: 10.7524/j.issn.0254-6108.2017090201
[18] 倪秀峰, 王儒威, 王继忠, 等. 燃煤电厂排放PAHs的气粒分配机制和排放通量 [J]. 中国环境科学, 2021, 41(1): 49-55. doi: 10.3969/j.issn.1000-6923.2021.01.006 NI X F, WANG R W, WANG J Z, et al. Studies on the gas-particle partitioning mechanism of polycyclic aromatic hydrocarbons(PAHs) and emission amount from coal-fired power plants [J]. China Environmental Science, 2021, 41(1): 49-55(in Chinese). doi: 10.3969/j.issn.1000-6923.2021.01.006
[19] 荆丹华, 牟玲, 王洁, 等. 机械炼焦过程生成飞灰中含碳组分分布特征 [J]. 中国环境科学, 2017, 37(11): 4097-4102. doi: 10.3969/j.issn.1000-6923.2017.11.011 JING D H, MU L, WANG J, et al. Characterization of carbon contents in fly ash from coking processes [J]. China Environmental Science, 2017, 37(11): 4097-4102(in Chinese). doi: 10.3969/j.issn.1000-6923.2017.11.011
[20] ANHUI STATISTICAL YEARBOOK. Natural resources and environmental protection [M]. China Statistics Press: Beijing, China, 2011-2018. [21] WANG R W, YOUSAF B, SUN R Y, et al. Emission characterization and δ13C values of parent PAHs and nitro-PAHs in size-segregated particulate matters from coal-fired power plants [J]. Journal of Hazardous Materials, 2016, 318: 487-496. doi: 10.1016/j.jhazmat.2016.07.030 [22] WANG R W, LIU G J, SUN R Y, et al. Emission characteristics for gaseous- and size-segregated particulate PAHs in coal combustion flue gas from circulating fluidized bed (CFB) boiler [J]. Environmental Pollution, 2018, 238: 581-589. doi: 10.1016/j.envpol.2018.03.051