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| Characteristic of deposits on different heating surfaces from a biomass-fired grate boiler |
| GONG Bin, YU Chun-jiang, WANG Zhun, LUO Zhong-yang |
| State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China |
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Abstract To solve the serious deposition problems on the heating surface from a biomass-fired grate boiler in china, which had affected the normal operation of the plant, the characteristic of deposits from different heating surfaces was analyzed. The micromorphology characteristic and element analysis of the deposits was conducted by scanning electron microscopy(SEM) and energy dispersive spectrometer(EDS), the crystal structure of the deposits were analyzed by X-ray diffraction(XRD). Influencing factors during the formating of the deposit including boiler designing, operating conditions, fuel properties were discussed. The results show that the high content of K,Ca,Cl and S in the fuels is the main reason for the deposition, KCl is the main component of the deposit, the high-Ca and low-Si in the fuel result in high-CaCO3 and low SiO2 and low silicate in the deposit; the content of Cl increases in the deposits from the water wall, high temperature superheater and low temperature superheater, while Ca and Si decrease with the decreasing flue gas temperature; the content of S increases rapidly in all the deposits layer close to the tube which exists in the form not only K3Na(SO4)2 but also CaSO4; because of the lacking of secondary air, the combustion of volatiles may cause reducing atmosphere in the upper space of the boiler, this favors the formation of K3Na(SO4)2 and eventually enhance the deposition problem.
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Published: 01 August 2015
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生物质炉排锅炉不同受热面沉积特性
针对国内某生物质炉排锅炉尾部受热面沉积情况严重影响正常运行的问题,对受热面沉积特性和规律进行研究分析.利用扫描电镜（SEM）与能谱（EDS）联合分析、X射线衍射分析（XRD）等手段对锅炉各受热面上采集的沉积物的微观形貌、元素及物相组成展开对比分析,结合锅炉设计、运行条件及燃料特性等影响因素对沉积机理进行探讨.研究表明,燃料中较高的K、Ca、Cl、S含量是导致沉积问题恶化的最主要原因,KCl是沉积物中最主要成分,燃料高Ca低Si的特性在沉积物中表现为CaCO3含量较高而SiO2、硅酸盐含量较低；随着烟气温度的降低,Cl在水冷壁、高温过热器、低温过热器沉积物中含量逐渐增加,而Ca、Si含量逐渐降低；在所有最贴近管壁的沉积物中,S的含量都明显偏高,含S物质除了K3Na(SO4)2外还有CaSO4；由于锅炉没有布置二次风,燃用生物质时炉膛上部局部出现还原性气氛可能促进了K3Na(SO4)2的生成,该因素进一步加剧了沉积问题.
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| ［1］ JENSEN P A, STENHOLM M, HALD P. Deposition investigation in straw-fired boilers ［J］. Energy & Fuels, 1997, 11(5): 1048-1055.
［2］ MILES T R, MILES JR T R, BAXTER L L, et al. Boiler deposits from firing biomass fuels ［J］. Biomass and Bioenergy, 1996, 10(2): 125-138.
［3］ 孙宏伟,吕薇,李瑞扬. 生物质燃烧过程中的碱金属问题研究［J］. 节能技术. 2009, 27(1): 24-26.
SUN Hong-wei, LV Wei, LI Rui-yang. Study on problems of alkali metal during straw combustion ［J］. Energy Conservation Technology, 2009, 27(1): 24-26.
［4］ 李廉明. 生物质流态化燃烧过程理论和实验研究［D］. 杭州：浙江大学, 2013.
LI Lian-ming. Theoretical and experimental studies on biomass fluidized combustion ［D］. Hangzhou: Zhejiang University, 2013.
［5］ 黄芳. 秸秆燃烧过程中受热面沉积腐蚀问题研究［D］. 杭州：浙江大学, 2013.
HUANG Fang. Study on the deposit and corrosion problem on heating surface during straw combustion ［D］. Hangzhou: Zhejiang University, 2013.
［6］ LIU H Y, TAN H Z, LIU Y, et al. Study of the layered structure of deposit in a biomass-fired boiler (case study) ［J］. Energy & Fuels, 2011, 25(6): 2593-2600.
［7］ BASHIR M S, JENSEN P A, FRANDSEN F, et al. Ash transformation and deposit build-up during biomass suspension and grate firing: Full-scale experimental studies ［J］. Fuel Processing Technology, 2012, 97: 93-106.
［8］ JAWED I, SKALNY J. Alkalies in cement: A review i. forms of alkalies and their effect on clinker formation ［J］. Cement and Concrete Research, 1977, 7(6): 719-729.
［9］ NIU Y Q, TAN H Z, MA L, et al. Slagging characteristics on the superheaters of a 12 MW Biomass-Fired Boiler ［J］. Energy & Fuels, 2010, 24: 6220.
［10］ CHRISTENSEN K A, STENHOLM M, LIVBJERG H. The formation of submicron aerosol particles, HCl and SO2 in straw-fired boilers ［J］. Journal of Aerosol Science, 1998, 29(4): 421-444.
［11］ 刘洋,刘正宁,谭厚章,等.生物质灰结渣机理研究［J］.工程热物理学报,2010(05): 895-899.
LIU Yang, LIU Zheng-ning, TAN Hou-zhang, et al. Mechanism of biomass ash slagging ［J］. Journal of Engineering Thermophysics, 2010(05): 895-899.
［12］ 刘洋,牛艳青,谭厚章,等.生物质锅炉二级过热器结渣恶化机制分析［J］.中国电机工程学报,2011(14): 8-12.
LIU Yang, NIU Yan-qing, TAN Hou-zhang et al. Mechanism of deterioration of the deposits on secondary super-heater in biomass-fired boiler ［J］. Proceedings of the CSEE, 2011(14): 8-12. |
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