|
|
|
| Dioxin suppression gases emission characteristics during particular sludge drying process |
| CHEN Tong, ZHAN Ming-xiu, LIN Xiao-qing, LI Xiao-dong, LU Sheng-yong, YAN Jian-hua |
| 1.State Key Laboratory of Clean Energy Utilization. Institute for Thermal Power Engineering, Zhejiang University, Hangzhou 310027, China |
|
|
|
Abstract In order to study the emission characteristic of dioxin suppression gases, including SO2, NH3, HCN, during sludge drying process, Gasmet was used to measure the concentration of these gases and other normal pollutants, including CO and NO2, when sludge was dried in the small-scale tube furnace. Moreover, the influences of drying temperature, type of sludge and drying atmosphere on the emission characteristics of dioxin suppression gases were also studied. The results show that the emission rates of SO2, NH3 and HCN were about 680, 1 570, 110 mg/(m3·s) when sludge (2 g)was heated for 50 min under N2. Furthermore, the results also reveal that the higher drying temperature was set, the shorter the emission time lasted; More NH3 generate under N2 atmosphere, but turning to SO2 under the simulated flue gas atmosphere; high N or S content of sludge generates moredioxin suppression gases in the some cases. Considering the emission characteristics of NH3 and HCN,θ =300~350 ℃ was chosen as the proper drying temperature. It’s good for dioxin suppression gases emission by intermittent heating, and it’s needed to pay attention to the reverse arrangement of sludge conveying and flue gas flowing in the industrial application to generate continuous suppression gases. We believe it is also available in a large-scale application after parameters modification.
|
|
Published: 01 February 2015
|
|
|
特定污泥干化过程中二恶英抑制气体排放特性
为了研究污泥干化过程中SO2、NH3、HCN等抑制二恶英生成的气体的排放特性,将干污泥放置于管式炉中加热干化,利用烟气分析仪Gasmet测量污泥干化过程中SO2、NH3和HCN等二恶英抑制气体及CO、NO2等其他常规污染物的排放浓度.研究干化温度、干化气氛、污泥种类对二恶英抑制气体排放的影响.试验结果表明,2 g上海干污泥在300 ml/min纯氮气氛中干化时,50 min内二恶英抑制气体SO2、NH3和HCN的平均排放速率分别为680,1 570,110 mg/(m3·s).干化温度越高,抑制气体排放越迅速,但持续时间越短；纯氮气氛中干化有利于NH3的排放,模拟烟气中有利于SO2的排放；含硫或含氮丰富的污泥有利于产生更多的抑制气体.考虑到NH3和HCN的排放特性,θ=300～350 ℃为合适的干化温度.通过比较发现,间断式升温能够最大程度地保证污泥干化过程中二恶英抑制气氛的排放,工业应用中应注意余热烟气和污泥输送逆向布置,保证污泥干化气的持续排放,适合规模化应用.
|
|
| ［1］ OLIE K, VERMEULEN P L, HUTZINGER O. Chlorodibenzo-p-dioxins and chlorodibenzofurans are trace components of fly ash and flue gas of some municipal incinerators in the Netherlands ［J］. Chemosphere, 1977, 6(8): 455-459.
［2］ MCKAY G. Dioxin characterisation, formation and minimisation during municipal solid waste (MSW) incineration: review ［J］. Chemical Engineering Journal, 2002, 86(3): 343-368.
［3］ LEMIEUX P M, LUTES C C, ABBOTT J A, et al. Emissions of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans from the open burning of household waste in barrels ［J］. Environmental Science & Technology, 2000, 34(3): 377-384.
［4］ RAGHUNATHAN K, GULLETT B K. Role of sulfur in reducing PCDD and PCDF formation ［J］. Environmental Science & Technology, 1996, 30(6): 1827-1834.
［5］ PANDELOVA M, LENOIR D, SCHRAMM K. Inhibition of PCDD/F and PCB formation in co-combustion ［J］. Journal of Hazardous Materials, 2007, 149(3): 615-618.
［6］ SAMARAS P, BLUMENSTOCK M, LENOIR D, et al. PCDD/F prevention by novel inhibitors: addition of inorganic S-and N-compounds in the fuel before combustion ［J］. Environmental Science & Technology, 2000, 34(24): 5092-5096.
［7］ ADDINK R, PAULUS R H, OLIE K. Prevention of polychlorinated dibenzo-p-dioxins/dibenzofurans formation on municipal waste incinerator fly ash using nitrogen and sulfur compounds ［J］. Environmental Science & Technology, 1996, 30(7): 2350-2354.
［8］ RUOKOJARVI P H, HALONEN I A, TUPPURAINEN K A, et al. Effect of gaseous inhibitors on PCDD/F formation ［J］. Environmental Science & Technology, 1998, 32(20): 3099-3103.
［9］ YAN M, LI X, YANG J, et al. Sludge as dioxins suppressant in hospital waste incineration ［J］. Waste Management, 2012, 32(7): 1453-1458.
［10］ DENG W, YAN J, LI X, et al. Emission characteristics of volatile compounds during sludges drying process ［J］. Journal of Hazardous Materials, 2009, 162(1): 186-192.
［11］ WITTER E, LOPEZ-REAL J. Nitrogen losses during the composting of sewage sludge, and the effectiveness of clay soil, zeolite, and compost in adsorbing the volatilized ammonia ［J］. Biological Wastes, 1988, 23(4): 279-294.
［12］ BUEKENS A, HUANG H. Comparative evaluation of techniques for controlling the formation and emission of chlorinated dioxins/furans in municipal waste incineration ［J］. Journal of Hazardous Materials, 1998, 62(1): 133.
［13］ KASAI E, KUZUHARA S, GOTO H, et al. Reduction in dioxin emissions by the addition of urea as aqueous solution to high-temperature combustion gas ［J］. ISIJ International, 2008, 48(9): 1305-1310.
［14］ TAKACS L, MOILANEN G L. Simultaneous control of PCDD/PCDF, HCI and NOX emissions from municipal solid waste incinerators with ammonia injection ［J］. Journal of the Air & Waste Management Association, 1991, 41(5): 716-722.
［15］ PEKAREK V, PUNCOCHAR M, BURES M, et al. Effects of sulfur dioxide, hydrogen peroxide and sulfuric acid on the de novo synthesis of PCDD/F and PCB under model laboratory conditions ［J］. Chemosphere, 2007, 66(10): 1947-1954.
［16］ RYAN S P, LI X, GULLETT B K, et al. Experimental study on the effect of SO2 on PCDD/F emissions: determination of the importance of gas-phase versus solid-phase reactions in PCDD/F formation ［J］. Environmental Science & Technology, 2006, 40(22): 7040-7047.
［17］ TUPPURAINEN K, HALONEN I, RUOKOJARVI P, et al. Formation of PCDDs and PCDFs in municipal waste incineration and its inhibition mechanisms: a review ［J］. Chemosphere, 1998, 36(7): 1493-1511.
［18］ GULLETT B K, BRUCE K R, BEACH L O. Effect of sulfur dioxide on the formation mechanism of polychlorinated dibenzodioxin and dibenzofuran in municipal waste combustors ［J］. Environmental Science & Technology, 1992, 26(10): 1938-1943.
［19］ TUPPURAINEN K, AATAMILA M, RUOKOJARVI P, et al. Effect of liquid inhibitors on PCDD/F formation. Prediction of particle-phase PCDD/F concentrations using PLS modelling with gas-phase chlorophenol concentrations as independent variables ［J］. Chemosphere, 1999, 38(10): 2205-2217.
［20］ MININNI G, SBRILLI A, GUERRIERO E, et al. Dioxins and furans formation in pilot incineration tests of sewage sludge spiked with organic chlorine ［J］. Chemosphere, 2004, 54(9): 1337-1350.
［21］ BUSER H R. Identification and sources of dioxin-like compounds: I. Polychlorodibenzothiophenes and polychlorothianthrenes, the sulfur-analogues of the polychlorodibenzofurans and polychlorodibenzodioxins ［J］. Chemosphere, 1992, 25(1): 45-48.
［22］ KASAI E, KUZUHARA S, GOTO H, et al. Reduction in dioxin emissions by the addition of urea as aqueous solution to high-temperature combustion gas ［J］. ISIJ International, 2008, 48(9): 1305-1310.
［23］ ISMO H, KARI T, JUHANI R. Formation of aromatic chlorinated compounds catalyzed by copper and iron ［J］. Chemosphere, 1997, 34(12): 2649-2662.
［24］ 方昕.浅谈生活垃圾焚烧炉二恶英排放的控制［J］.能源研究与管理.2010, 4: 25.
FANG Xin. Discussion on the controlling dioxin emission in refuse combustion boiler ［J］. Energy Research & Management, 2010, 4: 25.
［25］ CHEN H, NAMIOKA T, YOSHIKAWA K. Characteristics of tar, NOx precursors and their absorption performance with different scrubbing solvents during the pyrolysis of sewage sludge ［J］. Applied Energy, 2011, 88(12): 5032-5041.
［26］ 邓文义,严建华,李晓东,等. 造纸污泥干化及焚烧系统污染物排放特性［J］. 燃烧科学与技术. 2008, 14(6): 545-550.
DENG Wen-yi, YAN Jian-hua, LI Xiao-dong, et al. Pollutants emission characteristics of paper mill sludge drying and combustion system ［J］. Journal of Combustion Science and Technology, 2008, 14(6): 545-550.
［27］ 翁焕新,章金骏,刘瓉,等. 污泥干化过程氨的释放与控制［J］. 中国环境科学. 2011, 31(7): 1171-1177.
WENG Huan-xin, ZHANG Jin-jun, LIU Zan, et al. Characterization of ammonia release during sewage sludge drying process and its control ［J］. China Environmental Science, 2011, 31(7): 1171-1177.
［28］ SHAO K, YAN J, LI X, et al. Experimental study on the effects of H2O on PCDD/Fs formation by de novo synthesis in carbon/CuCl2 model system ［J］. Chemosphere, 2010, 78(6): 672-679.
［29］ OGAWA H, ORITA N, HORAGUCHI M, et al. Dioxin reduction by sulfur component addition ［J］. Chemosphere, 1996, 32(1): 151-157.
［30］ HAJIZADEH Y, ONWUDILI J A, WILLIAMS P T. Effects of gaseous NH3 and SO2 on the concentration profiles of PCDD/F in fly ash under post-combustion zone conditions ［J］. Waste Management, 2012, 32(7):1378-1386.
［31］ CHUN Y N, LIM M S, YOSHIKAWA K. Development of a high-efficiency rotary dryer for sewage sludge ［J］. Journal of Material Cycles and Waste Management, 2012, 14(1): 65-73.
［32］ DENG W, YAN J, LI X, et al. Emission characteristics of volatile compounds during sludges drying process ［J］. Journal of Hazardous Materials, 2009, 162(1): 186-192. |
|
Viewed |
|
|
|
Full text
|
|
|
|
|
Abstract
|
|
|
|
|
Cited |
|
|
|
|
| |
Shared |
|
|
|
|
| |
Discussed |
|
|
|
|
