市政污泥中低温气化及重金属迁移转化特性

doi:10.16085/j.issn.1000-6613.2017-2689

摘要/Abstract

摘要： 利用管式炉进行了污泥CO₂气化实验，并与N₂热解实验进行对比，系统研究了污泥中低温气化及重金属迁移转化特性。研究发现：热解过程中各可燃气体释放速率峰值出现的时间顺序为CO峰 < H₂次峰 < CH₄峰≈C_nH_m峰 < H₂主峰，气化过程中为CO主峰 < CH₄峰≈C_nH_m峰 < H₂主峰 < CO次峰。在450~550℃的区间内，气化和热解的冷煤气效率、样品失重率及残渣含碳量均相近，温度超过550℃冷煤气效率差距逐渐增大，温度超过700℃，样品失重率及残渣含碳量差距逐渐增大。气化温度为850℃时，冷煤气效率达87%。在450~700℃的区间内，气化残渣中Cr、Ni、Cu、Zn、As、Pb的残留率均随温度增加呈缓慢降低的趋势，在700~850℃区间，上述重金属的残留率下降较快。Cd的残留率在450~550℃区间缓慢下降，550~700℃区间快速降低，700~850℃区间缓慢降低。气化残渣中Cr、Ni、Zn、As、Cd的稳定形态所占比例相较于污泥原样明显提高，而Pb、Cu的稳定形态所占比例与污泥原样相近。污泥中温（700℃）气化时，冷煤气效率约为50%，气化残渣中Cr、Ni、Cu、Zn、As的残留率约为高温（850℃）下的1.2倍，Pb约为2.7倍，Cd为7.5倍，残渣中各重金属的稳定形态比例与高温时接近，环境危害性小。

关键词: 污泥, 管式炉, 气化, 热解, 重金属

Abstract: In this study, CO₂ gasification experiments of sludge were carried out in a tube furnace and compared with N₂ pyrolysis experiments. The characteristics of medium-low temperature gasification of sludge and the characteristics of heavy metals' migration and transformation in sludge were systematically studied. The results showed that the peak time of each combustible gas's releasing rate in pyrolysis experiment was in this order:peak of CO < side peak of H₂ < peak of CH₄ ≈peak of C_nH_m < main peak of H₂. But in gasification experiment, the time was in another order:main peak of CO < peak of CH₄ ≈ peak of C_nH_m < peak of H₂ < side peak of CO. The cold gas efficiencies, the weight loss rates of samples and the carbon's residual rates in gasification experiments and pyrolysis experiments were similar to each other when the temperature was between 450℃ and 550℃. However, the gap of cold gas efficiencies increased gradually when the temperature was over 550℃. The gap of weight loss rates of samples and carbon's residual rates increased gradually when the temperature was over 700℃. When the gasification temperature was 850℃, the cold gas efficiency was up to 87%. The residual rates of Cr, Ni, Cu, Zn, As, Pb in gasification residues firstly showed a slowly decreasing trend in the range of 450℃ to 700℃ and then dropped faster in the range of 700℃ to 850℃. The residual rate of Cd firstly decreased slowly in the range of 450℃ to 550℃, then decreased significantly in the range of 550℃ to 700℃ and lastly decreased slowly in the range of 700℃ to 850℃. After gasification, the stable morphology ratios of Cr, Ni, Zn, As and Cd in the residues were obviously higher than those ratios in original sludge. However, the stable morphology ratios of Pb and Cu are close to original sludge. When in medium temperature (700℃) gasification, the cold gas efficiency was about 50%. The residual rates of Cr, Ni, Cu, Zn and As in medium temperature gasification residues were about 1.2 times that of higher temperature (850℃). The rates of Pb and Cd in medium temperature gasification residues were about 2.7 times and 7.5 times that of higher temperature. The proportions of stable forms of heavy metals in residues of medium temperature gasification were close to high temperature, which was less harmful to the environment.

Key words: sewage sludge, tube furnace, gasification, pyrolysis, heavy metals

中图分类号:

TK123

张伟, 陈晓平, 杨叙军, 宋联, 朱葛, 马吉亮, 刘道银, 梁财. 市政污泥中低温气化及重金属迁移转化特性[J]. 化工进展, 2018, 37(09): 3657-3665.

ZHANG Wei, CHEN Xiaoping, YANG Xujun, SONG Lian, ZHU Ge, MA Jiliang, LIU Daoyin, LIANG Cai. Characteristics of medium-low temperature gasification of sewage sludge and migration and transformation of heavy metals[J]. Chemical Industry and Engineering Progress, 2018, 37(09): 3657-3665.

参考文献

[1] 张辉, 胡勤海, 吴祖成, 等.城市污泥能源化利用研究进展[J].化工进展, 2013, 32(5):1145-1151. ZHANG Hui, HU Qinhai, WU Zucheng, et al. Research progress on energy utilization of municipal sludge[J]. Chemical Industry and Engineering Progress, 2013, 32(5):1145-1151.
[2] 庄修政, 阴秀丽, 黄艳琴, 等.城市污泥水热脱水处理的工业应用与研究进展[J].化工进展, 2017, 36(11):4224-423. ZHUANG Xiuzheng, YIN Xiuli, HUANG Yanqin, et al. Progress in the industrial application and research of the treatment of water heat dehydration of municipal sludge[J]. Chemical Industry and Engineering Progress, 2017, 36(11):4224-423.
[3] KACPRZAK M, NECZAJ E, FIJALKOWSKI K, et al. Sewage sludge disposal strategies for sustainable development[J]. Environmental Research, 2017, 156:39-46.
[4] STUNDAZUJEVA A, KREICBERGS I, MEDNE O. Sustainable utilization of sewage sludge:review of technologies[J]. Key Engineering Materials, 2018, 762:121-125.
[5] NAKAKUBO T, TOKAI A, OHNO K. Comparative assessment of technological systems for recycling sludge and food waste aimed at greenhouse gas emissions reduction and phosphorus recovery[J]. Journal of Cleaner Production, 2012, 32:157-172.
[6] ABNISA F, DAUD W W, HUSIN W, et al. Utilization possibilities of palm shell as a source of biomass energy in Malaysia by producing bio-oil in pyrolysis process[J]. Biomass and Bioenergy, 2011, 35(5):1863-1872.
[7] DONG D, FENG Q, MCGROUTHER K, et al. Effects of biochar amendment on rice growth and nitrogen retention in a waterlogged paddy field[J]. Journal of Soils & Sediments, 2015, 15(1):153-162.
[8] 杨明沁, 解立平, 岳俊楠, 等.污水污泥气化焦油热解特性的研究[J].化工进展, 2015, 34(5):1472-1477. YANG Mingqin, JIE Liping, YUE Junnan, et al. Research on pyrolysis characteristics of sewage sludge gasification tar[J]. Chemical Industry and Engineering Progress, 2015, 34(5):1472-1477.
[9] 刘淑静, 李爱民, 袁维波. 温度对污泥焚烧残渣中重金属形态分布及残渣综合毒性的影响[J].安全与环境学报, 2008, 8(1):43-47. LIU Shujing, LI Aimin, YUAN Weibo. Effects of temperature on the distribution of heavy metals and the comprehensive toxicity of residues in sludge incineration residue[J]. Safety and Environmental Science, 2008, 8(1):43-47.
[10] 卢更, 刘欢, 胡红云, 等. 氧化钙调理污泥气化过程中重金属的迁移转化规律[J].化工学报, 2017, 68(1):272-280. LU Geng, LIU Huan, HU Hongyun, et al. Transport and transformation rules of heavy metals during calcium sludge gasification[J]. CIESC Journal, 2017, 68(1):272-280.
[11] KANG S, DONG J, KIM J, et al. Gasification and its emission characteristics for dried sewage sludge utilizing a fluidized bed gasifier[J]. Journal of Material Cycles and Waste Management, 2011, 13(3):180-185.
[12] ZHANG Y, XIAO B, HU Z, et al. Preparation of hydrogen-rich gas from steam gasification of sludge pyrolysis residues[J]. Renewable Energy Resources, 2012, 30(1):67-71.
[13] PETERSEN I, WERTHER J. Experimental investigation and modeling of gasification of sewage sludge in the circulating fluidized bed[J]. Chemical Engineering and Processing:Process Intensification, 2005, 44(7):717-736.
[14] 何丕文, 焦李, 肖波. 温度对干化污泥水蒸气气化产气特性的影响田[J].环境科学与技术, 2013, 36(5):1-3. HE Piwen, JIAO Li, XIAO Bo. Influence of temperature on vapor gasification characteristics of dry sludge vaporization[J]. Environmental Science and Technology, 2013, 36(5):1-3.
[15] TESSIER A W, CAMPBELL P G C, BISSON M, et al. Sequential extraction procedure for the speciation of particulate trace metals[J]. Analytical Chemistry, 1979, 51(7):844-850.
[16] 詹亚力, 戚琳琳, 郭绍辉, 等.剩余污泥热解及其残渣综合利用的研究进展[J]. 化工进展, 2009, 28(2):334-338. ZHAN Yali, QI Linlin, GUO Shaohui, et al. Progress of pyrolysis of sewage sludge and comprehensive utilization of its solid residue[J]. Chemical Industry and Engineering Progress, 2009, 28(2):334-338.
[17] 夏海渊.脱墨污泥热解气化特性研究[J].造纸科学与技术, 2012, 31(3):88-92. XIA Haiyuan. Characteristics of pyrolysis and gasification of deinking sludge[J]. Paper Science and Technology, 2012, 31(3):88-92.
[18] CABALLERO J A, MARCILLA A, et al. Characterization of sewage sludge by primary and secondary pyrolysis[J]. Journal of Analytical and Applied Pyrolysis, 1997, 40(97):433-450.
[19] 蔡旭, 黄群星, 王飞, 等. 污泥在CO₂ 气氛下热解CO与CH₄ 的生成特性[J]. 环境工程学报, 2016, 10(7):3779-3786. CAI Xu, HUANG Quansing, WANG Fei, et al. Synthesis characteristics of CO and CH₄ pyrolysis of sludge in CO₂ atmosphere[J]. Journal of Environmental Engineering, 2016, 10(7):3779-3786.
[20] SCOTT S A, DENNIS J S, DAVIDSON J F, et al. Thermogravimetric measurements of kinetics of pyrolysis of dried sewage sludge[J]. Fuel, 2006, 85(9):1248-1253.
[21] DOMINGGUEZ A, MENENDEZ J A, PIS J J, et al. Hydrogen rich fuel gas production from the pyrolysis of wet sewage sludge at high temperature[J]. Journal of Analytical and Applied Pyrolysis, 2006, 77:127-132.
[22] LEIMERT J M, TREIBER P, KARL J. The heat pipe reformer with optimized combustor design for enhanced cold gas efficiency[J]. Fuel Processing Technology, 2016, 141:68-73.
[23] 郑小艳.污泥热解气化残渣物化结构演变特性及其吸附性能的实验研究[D]. 杭州:浙江工业大学, 2015. ZHENG Xiaoyan. Experimental study on the physicochemical structural evolution characteristics and adsorption properties of pyrolysis and gasification residue of sludge[D]. Hangzhou:Zhejiang University of Technology, 2015.
[24] 李智伟, 王兴栋, 林景江, 等. 污泥生物炭制备过程中氮磷钾及重金属的迁移行为[J]. 环境工程学报, 2016, 10(3):1392-1399. LI Zhiwei, WANG Xingdong, LIN Jingjiang, et al. Migration of nitrogen, phosphorus, potassium and heavy metals during the preparation of sludge biochar[J]. Journal of Environmental Engineering, 2016, 10(3):1392-1399.
[25] 陈宗良.污泥热处理过程中重金属的迁移特性研究[D].沈阳:沈阳航空航天大学, 2011. CHEN Zongliang. Study on migration characteristics of heavy metals during sludge heat treatment[D]. Shenyang:Shenyang University of Aeronautics and Astronautics, 2011.
[26] 方平, 唐子君, 钟佩怡, 等.城市污泥焚烧渣中重金属的浸出特性[J]. 化工进展, 2017, 36(6):2304-2310. FANG Ping, TANG Zijun, ZHONG Peiyi, et al. Leaching characteristics of heavy metals in municipal sludge incineration residue[J]. Chemical Industry and Engineering Progress, 2017, 36(6):2304-2310.
[27] 郭子逸, 邵敬爱, 杨海平, 等. 污泥热解处理过程中重金属迁移与转化规律综述[J]. 能源与环境, 2016(4):65-66, 68. GUO Ziyi, SHAO Jingai, YANG Haiping, et al. Review of the migration and transformation of heavy metals during pyrolysis of sludge[J]. Energy and Environment, 2016(4):65-66, 68.
[28] MENG Aihong, LI Qinghai, JIA Jinyan, et al. Experimental study on the effect of waste water on the migration and transformation of heavy metals in the process of waste incineration[J]. Chinese Journal of Chemical Engineering, 2012, 20(5):1008-1015.
[29] ZORPAS A A, VLYSSIDES A G, ZORPAS G A, et al. Impact of thermal treatment on metal in sewage sludge from the Psittaliss waste water treatment plant, Athens, Greece[J]. Journal of Hazardous Materials, 2001, 82(3):291-298.
[30] ZHANG Pu, LI Haibin, ZHAO Zengli. Influence of temperature on the mental form distribution in the pyrolysis residue of sewage sludge[C]//Monograph of 2005 China Conference on Biomass Energy Technology and Sustainable Development. Jinan:Chinese Solar Energy Society, 2005:399-405.