Study on the environmental effects of heavy metals in coal gangue and coal combustion by ReCiPe2016 for life cycle impact assessment
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摘要: 在煤和煤矸石燃烧的过程中,许多重金属污染物排放到大气中,从而造成严重的环境问题,因此研究煤燃烧过程中重金属排放的环境效应很有必要。本研究运用ReCiPe2016软件计算了煤矸石和煤在330 MW煤粉炉、50 kW循环流化床和实验室燃烧时As和Pb排放的环境影响值。结果表明当煤在330 MW煤粉炉燃烧的时候,底渣、飞灰、烟气中的As排放对环境的影响值分别是3.28×10-6、2.68×10-5、3.89×10-3,底渣、飞灰、烟气中的Pb排放对环境的影响值分别是8.57×10-6、6.00×10-5、4.83×10-2。底渣中的As和Pb排放对环境的影响比飞灰中低;As和Pb排放到大气对环境的影响比排放到土壤高。另外,当煤在50 kW循环流化床燃烧的时候,飞灰中的As和Pb排放对环境的影响值分别是3.26×10-5和1.28×10-4,底渣中的As和Pb排放对环境的影响值分别是1.16×10-6和1.43×10-5。本文的研究结果还表明当煤矸石在实验室燃烧的时候,随着燃烧温度的升高,As和Pb排放对环境的影响值升高。另外,As和Pb排放到大气对环境的影响占总环境的影响比例比排放到土壤高。此项研究还表明当煤在煤粉炉和循环流化床燃烧的时候,相同工况下Pb排放对环境的影响比As高。这项结果也为运用生命周期影响评价软件预测煤矸石在循环流化床燃烧As和Pb排放的环境影响提供基础数据。Abstract: During coal and coal gangue combustion, many heavy metal pollutants are emitted and cause serious environmental problems. In this paper, the environmental effect values of As and Pb emission during coal gangue and coal combustion in the 330 MW pulverized coal boiler, 50 kW circulated fluidized bed boiler and laboratory were calculated by ReCiPe2016. The results show that when coal combustion in 330 MW pulverized coal boiler, the environment effect values of As for bottom slag, fly ash and flue gas are 3.28×10-6, 2.68×10-5 and 3.89×10-3 respectively; while the environment effect value of Pb for bottom slag, fly ash and flue gas are 8.57×10-6, 6.00×10-5 and 4.83×10-2, respectively. The environmental effects of As and Pb in bottom slag are lower than those in the fly ash; and the environmental effects of As and Pb on air are higher than those on soil. Moreover, when coal combustion in the 50 kW circulated fluidized boiler, the effect values of As and Pb in fly ash on environment are 3.26×10-5 and 1.28×10-4; and the effect values of As and Pb in bottom slag are 1.16×10-6 and 1.43×10-5 respectively. The results also show that when coal gangue combustion in the laboratory, the effect values of As and Pb emission increase with increasing of the temperature; and the proportions of total environmental effects of As and Pb on air are higher than those on soil. Besides that, this study also indicates that the effect of Pb emitted into environment is higher than that of As at the same conditions during coal combustion both in circulated fluidized boiler and pulverized coal boiler. The results may provide basic data for predicting the environmental effects of As and Pb during coal gangue combustion in circulating fluidized bed for life cycle impact assessment.
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Key words:
- coal gangue /
- heavy metals /
- combustion /
- environmental effect
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Table 1 Relative mass distribution of As and Pb from the 330 MW pulverized coal boiler
Heavy metal Distribution w/% bottom slag fly ash flue gas As 9.61 78.64 0.03 Pb 11.18 78.04 0.87 Table 2 Environmental effects of As and Pb emission during coal combustion in the 330 MW pulverized coal boiler
Ash location Environmental effect value (1, 4-DCB eq. emitted to environment) As Pb Bottom slag 3.28×10-6 8.57×10-6 Fly ash 2.68×10-5 6.00×10-5 Flue gas 3.89×10-3 4.83×10-2 Table 3 Relative mass distribution rate of As and Pb from 50 kW circulated fluidized bed boiler
Heavy metal Distributian w/% bottom slag fly ash As 3.44 96.56 Pb 9.38 90.62 Table 4 Environmental effects of As and Pb emission during coal combustion in 50 kW circulated fluidized bed boiler
Ash location Environmental effect value (1, 4-DCB eq.
emitted to environment)As Pb Bottom slag 1.16×10-6 1.43×10-5 Fly ash 3.26×10-5 1.38×10-4 Table 5 Volatilization rates of As and Pb during coal gangue combustion
Heavy metal Volatilization rate /% 900 ℃ 1000 ℃ As 94.68 95.19 Pb 79.68 81.43 Table 6 Proportion of total effect of combustion As emission in laboratory
Temperature /℃ Combustion w/% into soil into air 900 2.6221×10-4 99.9997 1000 2.6298×10-4 99.9997 Table 7 Proportion of total effect of combustion Pb emission in laboratory
Temperature /℃ Combustion w/% into soil into air 900 1.3784×10-2 99.9862 1000 1.3814×10-2 99.9861 -
[1] XIE H, NIE A. The modes of occurrence and washing floatation characteristic of arsenic in coal from western Guizhou[J]. J China Coal Soc, 2010, 35(1): 117-121. http://www.zhangqiaokeyan.com/academic-journal-cn_journal-china-coal-society_thesis/0201216150122.html [2] FENG H. The methods of instrumental analysis on arsenic, mercury, chlorie in coal and the study on the law of migration of arsenic, mercury from coal combustion[D]. Chengdu: Chengdu University of Technology, 2010. [3] KOLKER A, SENIOR C L, QUICK J C. Mercury in coal and the impact of coal quality on mercury emissions from combustion system[J]. Appl Geochem, 2006, 21: 1821-1836. doi: 10.1016/j.apgeochem.2006.08.001 [4] CAO Y, GUO S, ZHAI J. Study on the occurrence modes of mercury and arsenic in coal gangue[J]. Coal Geol Explor, 2017, 45(1): 26-30. http://en.cnki.com.cn/Article_en/CJFDTotal-MDKT201701005.htm [5] ZHOU C, LIU G, FANG T, WU D, LAM P K S. Partitioning and transformation behavior of toxic elements during circulated fluidized bed combustion of coal gangue[J]. Fuel, 2014, 135: 1-8. doi: 10.1016/j.fuel.2014.06.034 [6] ZHOU C, LIU G, YAN Z, FANG T, WANG R. Transformation behavior of mineral composition and trace elements during coal gangue combustion[J]. Fuel, 2012, 97: 244-250. http://www.sciencedirect.com/science/article/pii/S0016236112001500 [7] LU P, XIE J, ZHANG X, WANG J. Release properties of semi-volatile heavy metals in sewage sludge/coal co-incineration under O2/CO2 atmosphere[J]. J Fuel Chem Technol, 2020, 48(5): 533-542. https://www.sciencedirect.com/science/article/pii/S0255270108000731 [8] ZHANG Y, NAKANO J, LIU L, WANG X, ZHANG Z. Trace element partitioning behavior of coal gangue-fired CFB plant: Experimental and equilibrium calculation[J]. Environ Sci Pollut Res, 2015, 22: 15469-15478. doi: 10.1007/s11356-015-4738-6 [9] LIU H, WANG C, HUANG X, ZHANG Y, SUN X. Volatilization of arsenic in coal during oxy-fuel combustion[J]. J Chem Ind Eng, 2015, 66(12): 5079-5087. [10] SPÖRL R, MAIER J, BELO L, SHAH K, STANGER R, WALL T, SCHEFFKNECHT G. Mercury and SO3 Emissions in Oxy-Fuel Combustion[J]. Energ Proc, 2014, 63: 386-402. doi: 10.1016/j.egypro.2014.11.041 [11] CHEN Y. Migration law of flue gas mercury from coal-fired plant ULE system[J]. Electron Power Sci Technol Environ Prot, 2017, 33(1): 9-11. http://www.en.cnki.com.cn/Article_en/CJFDTOTAL-DLHB201701003.htm [12] WANG X, LI S, WANG W, BISWAS P. Mercury oxidation during coal combustion by injection of vanadium pentoxide(V2O5)[J]. Int J Coal Geol, 2017, 170: 54-59. doi: 10.1016/j.coal.2016.10.009 [13] HOFFART A, SEAMES W, KOZLIAK E, RIEDINGER S, FRANCINI J, CARLSON C. A two-step acid mercury removal process for pulverized coal[J]. Fuel, 2006, 85: 1166-1173. doi: 10.1016/j.fuel.2005.11.020 [14] MARCZAK M, WIERONSKA F, BURMISTRZ P, STRUGALA A, KOGUT K, LECH S. Investigation of subbituminous coal and lignite combustion process in terms of mercury and arsenic removal[J]. Fuel, 2019, 251: 572-579. doi: 10.1016/j.fuel.2019.04.082 [15] DUAN P, WANG W, SANG S, MA M, WANG J, ZHANG W. Modes of occurrence and removal of toxic elements from high-uranium coals of Rongyang Mine by stepped release flotation[J]. Energy Sci Eng, 2019, 7: 1678-1686. doi: 10.1002/ese3.384 [16] TIAN L, WU H, DENG H, CHEN D, BAI X, LI J. Ecological risks of heavy metal contamination in soils around the coal gangue dump in the coal mining area[J]. Guizhou Agric Sci, 2013, 41(1): 123-127. [17] FINKELMAN R B. Potential health impacts of burning coal beds and waste banks[J]. Coal Geol, 2004, 59: 19-24. doi: 10.1016/j.coal.2003.11.002 [18] LIU C, ZHOU C, ZHANG N, PAN J, CAO S, TANG M, JI W, HU T. Modes of occurrence and partitioning behavior and trace elements during coal preparation-A case study in Guizhou Province, China[J]. Fuel, 2019, 243: 79-87. doi: 10.1016/j.fuel.2019.01.106 [19] KONG S, LIU Y, ZENG H, XIE Q, LV X. Current progress in research on the pollution of volatile heavy metals from incineration plant to its ambient soil and vegetation[J]. Ecol Environ Sci, 2010, 19(4): 985-990. https://core.ac.uk/display/155515416 [20] ZHANG H, ZENG F, FANG Hg, LIN S. Sedimentation and capacity of cadmiunm in Beijing River[J]. Environ Sci Techno, 2010, 33(8): 120-123. http://www.cabdirect.org/abstracts/20103325407.html [21] MAHMUD M A P, HUDA N, FARJANA S H, LANG C. A strategic impact assessment of hydropower plants in alpine and non-alpine areas of Europe[J]. Appl Energ, 2019, 250: 198-214. doi: 10.1016/j.apenergy.2019.05.007 [22] HUIJBREGTS M A J, STEINMANN Z J N, ELSHOUT P M F, STAM G, VERONES F, VIEIRA M, ZIJP M, HOLLANDER A, ZELM R V. ReCiPe2016: A harmonised life cycle assessment method at midpoint and endpoint level(vol 22, pg 138, 2017)[J]. Int J Life Cycle Ass, 2020, 25(8): 1635-1635. doi: 10.1007/s11367-020-01761-5 [23] KLEDJA C, ANDI M, VITO C, MLADEN T. LCA of tomato greenhouse production using spatially differentiated life cycle impact assessment indicators: An Albanian case study[J]. Environ Sci Pollut Res, 2020, 27(7): 6960-6970. doi: 10.1007/s11356-019-07191-7 [24] HUA W, SUN H, QI J, HUANG Z, SHI Z, DUAN L. Emission characteristics of Pb and As from an ultra-low emission coal-fired power plant[J]. Therm Power Gener, 2019, 48(10): 65-70. [25] XU W, ZENG R. The impacts of the environmental upon arsenic in coal-burned wastes from a power plant[J]. J Minaer Petrol, 2013(4): 110-114. [26] ZHUO Y, AN Z, LIU Y, CHEN C. Relation between trace element enrichment and PM10 diameter from coal-fired power plants[J]. J Tsinghua Univ: Nat Sci Ed, 2013.53(3): 323-329. https://www.sciencedirect.com/science/article/pii/S0016236109002890 [27] WANG M, ZHANG X, YANG N, LIU K, QIN F, WU Y. Study on the environmental impact of high arsenic coal utilization[J]. Coal Convers, 2012, 35(4): 77-79. http://www.zhangqiaokeyan.com/academic-journal-cn_coal-conversion_thesis/0201242578937.html [28] ZHUANG R, FAN Dn, CHEN Z, XU X, LIN G, WANG H, CAI C, XIONG M, HUANG H, WANG C. Harmless treatment of arsenic-bearing acidic wastewater and speciation and stability analysis of slag[J]. Nonferrous Met, 2018.5: 69-73. http://en.cnki.com.cn/Article_en/CJFDTotal-METE201805016.htm [29] CHEN Y, HE K. Analysis of chromium and lead in coal combustion[J]. Mod Business Trade Ind, 2007.6:178-179. [30] ZHAO S, DUAN Y, ZHOU Q, ZHANG J, DU H, TANG H, LV J. Experimental study on trace elements emission characteristics in coal-fired circulating fluidized bed[J]. Proc CSEE, 2017, 37(1): 193-199. http://www.researchgate.net/publication/317027357_Experimental_study_on_trace_elements_emission_characteristics_in_coal-fired_circulating_fluidized_bed [31] PENG H, WANG B, YANG F, CAO Y, CHENG F. Emission characteristics of heavy metal during combustion of coal gangue and coal slime[J]. Clean Coal Technol, 2019, 25(5): 118-124.