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浙江大学学报(工学版)
Journal of ZheJiang University (Engineering Science)  2020, Vol. 54 Issue (10): 1955-1963    DOI: 10.3785/j.issn.1008-973X.2020.10.012
    
Experimental study on slagging characteristics during coal and biomass co-combustion with on-line measurement technique
Jia-kai ZHANG1(),Li NIE2,Ke-fa CEN1,Xiao JIANG1,Hao ZHOU1,*()
1. State Key Laboratory of Clean Energy Utilization, Zhejiang University, Hangzhou 310027, China
2. Dongfang Boiler Limited Company, Dongfang Electric Corporation, Chengdu 611731, China
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Abstract  

An online measurement technique was applied to analyze the slagging characteristics during co-combustion of coal and stalk in a 50 kW furnace. Results showed that with the addition of biomass stalk, the stable slag thickness increased and the stable relative heat flux decreased compared with combustion of pure coal. When the mass ratio of corn stalks is 0%, 6.7%, 15%, 22%, the corresponding stable thickness of the slag were 1.37, 2.51, 5.21, 5.38 mm, and the stable relative heat fluxes were 0.44, 0.42, 0.37, 0.35. When the mass proportions of peanut stalks were 6.7%, 15%, and 22%, the corresponding stable thickness of the slag were 3.37, 3.89, and 5.33 mm, and the stable relative heat fluxes were 0.39, 0.36, and 0.30. The liquid slag mass fraction which was obtained by Factsage increased significantly when coal was co-fired with stalk. Base-to-acid ratio showed a good performance in predicting the ash behavior and slagging tendency by using four slagging indexes.

Key words： ash deposition      on-line measurement      heat flux      biomass      slagging indice     
Received: 16 August 2019      Published: 28 October 2020
CLC:  TK 11  
Corresponding Authors: Hao ZHOU     E-mail: zhangjiakai_111@163.com;zhouhao@cmee.zju.edu.cn
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Cite this article:

Jia-kai ZHANG,Li NIE,Ke-fa CEN,Xiao JIANG,Hao ZHOU. Experimental study on slagging characteristics during coal and biomass co-combustion with on-line measurement technique. Journal of ZheJiang University (Engineering Science), 2020, 54(10): 1955-1963.

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http://www.zjujournals.com/eng/10.3785/j.issn.1008-973X.2020.10.012     OR     http://www.zjujournals.com/eng/Y2020/V54/I10/1955


生物质秸秆与神府烟煤掺烧结渣特性的在线监测

利用自主开发的在线监测系统，在50 kW的下行炉探究2种生物质秸秆与神府烟煤掺烧的结渣特性. 结果表明，随着生物质秸秆的掺烧，灰渣的稳定厚度增加，稳定热流减小. 当掺烧玉米秸秆质量分数为0%、6.7%、15%、22%时，相应的灰渣稳定厚度为1.37、2.51、5.21、5.38 mm，稳定相对热流密度为0.44、0.42、0.37、0.35. 当掺烧花生秸秆质量分数为6.7%、15%、22%时，相应的灰渣稳定厚度为3.37、3.89、5.33 mm，稳定相对热流密度为0.39、0.36、0.30. 利用热力学计算软件Factsage进行化学平衡计算发现，随着秸秆掺烧比例的增加，灰中熔融相的质量分数增加. 用4种结渣指数对生物质掺烧结渣进行预判，碱酸比的预测最准确.


关键词： 灰沉积,  在线监测,  热流密度,  生物质,  结渣指数 
Fig.1 Experimental device of 50 kW furnace
Fig.2 Schematic diagram of on-line measurement system
燃料 工业分析1）wB/% 元素分析2）wB/% 低位发热量/
（MJ·kg?1） 		灰熔点/°C
水分 挥发分 固定碳 灰分 C H N S O DT ST HT FT
神府烟煤 8.77 26.96 48.96 15.32 77.94 4.47 1.42 0.34 15.83 22.57 1234 1257 1275 1302
玉米秸秆 8.47 68.19 16.22 7.12 48.57 5.67 1.09 0.20 44.47 15.23 980 1220 1240 1310
花生秸秆 9.39 64.54 15.67 10.40 48.87 5.80 1.60 0.25 43.48 14.51 1180 1220 1240 1250
Tab.1 Fuel characteristics of bituminous coal and biomass straw
燃料 灰成分wB/%
Na2O MgO Al2O3 SiO2 P2O5 SO3 K2O CaO TiO2 Fe2O3
注：1）空气干燥基；2）干燥无灰基.
神府烟煤 0.05 1.13 27.95 55.19 0.34 1.06 0.25 6.34 0.78 6.92
玉米秸秆 0.76 2.76 9.22 56.77 1.72 2.57 19.57 6.37 0.27 0.00
花生秸秆 0.79 3.46 12.78 43.13 2.43 4.49 19.84 11.88 0.33 0.85
Tab.1 
参数 数值
过量空气系数 1.1
炉膛功率/kW 50
燃料量/（kg·h?1） 8.0
一次风量/（m3·h?1），风温/°C 12.8，80
二次风量/（m3·h?1），风温/°C 3.5，300
三次风量/（m3·h?1），风温/°C 9.0，272
燃尽风量/（m3·h?1），风温/°C 18.6，292
燃料量/（kg·h?1） 8.0
炉内烟气流速/（m·s?1） 2.0
炉膛温度/°C 1 200
炉膛出口φ(O2)/% 4
探针内部导热油温度/°C 230
灰沉积时间/min 120
Tab.2 Operation conditions of furnace
工况 wB/% 工况 wB/%
工况1 纯烟煤 工况5 花生秸秆：6.7
工况2 玉米秸秆：6.7 工况6 花生秸秆：15
工况3 玉米秸秆：15 工况7 花生秸秆：22
工况4 玉米秸秆：22 ? ?
Tab.3 Experiment conditions of coal and biomass co-combustion
Fig.3 Schematic diagram of thickness equation[20]
Fig.4 Ash growth curve of bituminous coal mixed with different mass fractions of corn stalks
Fig.5 Ash growth curve of bituminous coal mixed with different mass fractions of peanut straw
掺烧工况 H/mm q/q0
工况1 1.37 0.44
工况2 2.51 0.42
工况3 5.21 0.37
工况4 5.38 0.35
工况5 3.37 0.39
工况6 3.89 0.36
工况7 5.33 0.30
Tab.4 Experiment results of coal and biomass co-combustion
Fig.6 Relative heat fluxes and probe surface temperatures under condition of blending bituminous coal with different mass fractions of corn stalks
Fig.7 Relative heat fluxes and probe surface temperatures under condition of blending bituminous coal with different mass fractions of peanut straw
%
掺烧工况 w（Na） w（Mg） w（Al） w（Si） w（P） w（S） w（K） w（Ca） w（Ti） w（Fe）
工况1 1.34 1.77 13.32 47.26 0.82 4.03 2.09 12.05 1.26 16.06
工况2 1.26 1.20 11.15 51.67 0.35 4.12 3.75 12.94 1.20 12.35
工况3 1.33 1.13 10.37 50.80 0.75 6.62 4.13 13.93 0.74 10.19
工况4 1.33 1.38 10.55 52.55 0.83 4.35 6.04 12.18 0.75 9.67
工况5 0.97 1.27 12.86 50.39 0.70 4.14 3.42 11.60 1.09 13.55
工况6 1.56 1.45 13.53 45.86 0.72 5.29 5.74 10.69 1.29 13.54
工况7 1.69 1.45 14.64 46.25 0.67 4.62 5.57 11.54 0.98 12.58
Tab.5 Element distribution in initial layer of ash
代码 物质 数据库 相
436 MgO（SLAG A） FACT FACT-SLAG A
437 FeO（SLAG A） FACT FACT-SLAG A
438 MnO（SLAG A） FACT FACT-SLAG A
439 Na2O（SLAG A） FACT FACT-SLAG A
440 SiO2（SLAG A） FACT FACT-SLAG A
441 TiO2（SLAG A） FACT FACT-SLAG A
442 Ti2O3（SLAG A） FACT FACT-SLAG A
443 CaO（SLAG A） FACT FACT-SLAG A
444 Al2O3（SLAG A） FACT FACT-SLAG A
445 K2O（SLAG A） FACT FACT-SLAG A
Tab.6 List of slagging systems and their components selected in chemical equilibrium calculation
%
掺烧工况 w（Na2O） w（MgO） w（Al2O3） w（SiO2） w（P2O5） w（SO3） w（K2O） w（CaO） w（TiO2） w（Fe2O3）
工况1 0.05 1.13 27.95 55.19 0.34 1.06 0.25 6.34 0.78 6.92
工况2 0.10 1.24 26.69 55.29 0.43 1.16 1.55 6.34 0.75 6.46
工况3 0.16 1.37 25.14 55.42 0.54 1.28 3.15 6.34 0.71 5.88
工况4 0.21 1.49 23.83 55.53 0.64 1.39 4.50 6.35 0.67 5.4
工况5 0.10 1.28 26.93 54.38 0.48 1.29 1.57 6.71 0.75 6.51
工况6 0.16 1.48 25.67 53.38 0.65 1.57 3.19 7.17 0.71 6.01
工况7 0.21 1.64 24.61 52.53 0.80 1.81 4.56 7.56 0.68 5.58
Tab.7 Ash composition under various working conditions
Fig.8 Liquid slag mass fraction under various working conditions
序号 结渣指数 判别界限
轻微 中等 严重
1 硅比 78.8 66.1~78.8 66.1
2 硅铝比 <1.87 1.87~2.65 >2.65
3 碱酸比 <0.2 0.2~0.4 >0.4
4 铁钙比 <0.3或>3 0.3~3（不包含≈1） ≈1
Tab.8 Discrimination range of slagging index
工况 硅比 硅铝比 碱酸比 铁钙比
工况1 79.32 1.97 0.18 1.09
工况1 轻微 中等 轻微 严重
工况2 79.76 2.07 0.19 1.02
工况2 轻微 中等 轻微 严重
工况3 80.30 2.20 0.21 0.93
工况3 轻微 中等 中等 严重
工况4 80.76 2.33 0.22 0.85
工况4 轻微 中等 中等 中等
工况5 78.94 2.02 0.20 0.97
工况5 轻微 中等 中等 严重
工况6 78.46 2.08 0.23 0.84
工况6 中等 中等 中等 中等
工况7 78.04 2.13 0.25 0.74
工况7 中等 中等 中等 中等
Tab.9 Slag index prediction result
[1]   ZHOU W, SWANSON L, MOYEDA D, et al Process evaluation of biomass cofiring and reburning in utility boilers[J]. Energy and Fuels, 2010, 24 (8): 4510- 4517
doi: 10.1021/ef1005379
[2]   宁新宇, 李诗媛, 吕清刚, 等 秸秆类生物质与石煤在流化床中的混烧与黏结机制[J]. 中国电机工程学报, 2008, 28 (29): 105- 110
NING Xin-yu, LI Shi-yuan, LV Qing-gang, et al Study on co-firing and agglomeration mechanism of stalk biomass and stone coal in fluidized bed[J]. Proceedings of the CSEE, 2008, 28 (29): 105- 110
[3]   BARTOLOME C, GIL A Ash deposition and fouling tendency of two energy crops (cynara and poplar) and a forest residue (pine chips) co-fired with coal in a pulverized fuel pilot plant[J]. Energy and Fuels, 2013, 27 (10): 878- 889
[4]   陈炜, 段佳, 林鹏, 等 氧量对典型生物质燃烧特性的影响[J]. 中国电机工程学报, 2008, 28 (2): 43- 48
CHEN Wei, DUAN Jia, LIN Peng, et al Effect of oxygen concentration on combustion characteristics of typical biomass material[J]. Proceedings of the CSEE, 2008, 28 (2): 43- 48
[5]   栾积毅, 孙锐, 路军锋, 等 生物质再燃脱硝的试验研究[J]. 中国电机工程学报, 2008, 28 (14): 73- 79
LUAN Ji-yi, SUN Rui, LU Jun-feng, et al Experimental studies on reburning with biomass for NOx reduction[J]. Proceedings of the CSEE, 2008, 28 (14): 73- 79
[6]   NIU Y, TAN H, HUI S Ash-related issues during biomass combustion: Alkali-induced slagging, silicate melt-induced slagging (ash fusion), agglomeration, corrosion, ash utilization, and related countermeasures[J]. Progress in Energy and Combustion Science, 2016, 52: 1- 61
doi: 10.1016/j.pecs.2015.09.003
[7]   WANG X, TAN H, NIU Y, et al Experimental investigation on biomass co-firing in a 300 MW pulverized coal-fired utility furnace in China[J]. Proceedings of the Combustion Institute, 2011, 33 (2): 2725- 2733
doi: 10.1016/j.proci.2010.06.055
[8]   VAMVUKA D, MISTAKIDOU E, DRAKONAKI S, et al Ash quality of a beneficiated lignite from Ptolemais Basin, Northern Greece[J]. Energy and Fuels, 2001, 15: 1181- 1185
doi: 10.1021/ef0100193
[9]   ZHENG Z, WANG H, CAI Y, et al A novel method used to study growth of ash deposition and in situ measurement of effective thermal conductivity of ash deposit[J]. Heat Transfer-Asian Research, 2018, 47: 271- 285
doi: 10.1002/htj.21302
[10]   WANG Y, TAN H, WANG X, et al The condensation and thermodynamic characteristics of alkali compound vapors on wall during wheat straw combustion[J]. Fuel, 2017, 187: 33- 42
doi: 10.1016/j.fuel.2016.09.014
[11]   LUAN C, YOU C, ZHANG D Composition and sintering characteristics of ashes from co-firing of coal and biomass in a laboratory-scale drop tube furnace[J]. Energy, 2014, 69: 562- 570
doi: 10.1016/j.energy.2014.03.050
[12]   ROBINSON A, JUNKER H, BAXTER L Pilot-scale investigation of the influence of coal?biomass cofiring on ash deposition[J]. Energy and Fuels, 2002, 16 (2): 343- 355
doi: 10.1021/ef010128h
[13]   WANG G, PINTO T, COSTA M Investigation on ash deposit formation during the co-firing of coal with agricultural residues in a large-scale laboratory furnace[J]. Fuel, 2014, 117: 269- 277
doi: 10.1016/j.fuel.2013.09.084
[14]   KUPKA T, MANCINI M, IRMER M, WEBER R Investigation of ash deposit formation during co-firing of coal with sewage sludge, sawdust and refuse derived fuel[J]. Fuel, 2008, 87 (12): 2824- 2837
doi: 10.1016/j.fuel.2008.01.024
[15]   MOLCAN P, LU G, BRIS T, et al Characterisation of biomass and coal co-firing on a 3 MWth combustion test facility using flame imaging and gas/ash sampling techniques[J]. Fuel, 2009, 88 (12): 2328- 2334
doi: 10.1016/j.fuel.2009.06.027
[16]   NIU Y, TAN H, MA L, et al Slagging characteristics on the superheaters of a 12 MW biomass-fired boiler[J]. Energy and Fuels, 2010, 24 (11): 5222- 5227
[17]   PANG C, HEWAKANDAMBY B, WU T, et al An automated ash fusion test for characterization of the behaviour of ashes from biomass and coal at elevated temperatures[J]. Fuel, 2013, 103: 454- 466
doi: 10.1016/j.fuel.2012.06.120
[18]   LI Q, ZHANG Y, MENG A, et al Study on ash fusion temperature using original and simulated biomass ashes[J]. Fuel Processing Technology, 2013, 107: 107- 112
doi: 10.1016/j.fuproc.2012.08.012
[19]   FANG X, JIA L Experimental study on ash fusion characteristics of biomass[J]. Bioresource Technology, 2012, 104: 769- 774
doi: 10.1016/j.biortech.2011.11.055
[20]   ZHOU H, ZHANG J, ZHANG K Investigation of the deposition characteristics of ammonium bisulfate and fly ash blend using an on-line digital image technique: effect of deposition surface temperature[J]. Fuel Processing Technology, 2018, 179: 359- 368
doi: 10.1016/j.fuproc.2018.07.030
[21]   YANG X, INGHAM D, MA L, et al Predicting ash deposition behaviour for co-combustion of palm kernel with coal based on CFD modelling of particle impaction and sticking[J]. Fuel, 2016, 165: 41- 49
doi: 10.1016/j.fuel.2015.10.056
[22]   NIU Y, ZHU Y, TAN H, et al Investigations on biomass slagging in utility boiler: criterion numbers and slagging growth mechanisms[J]. Fuel Processing Technology, 2014, 128: 499- 508
doi: 10.1016/j.fuproc.2014.07.038
[23]   周斌. 劣质煤积灰结渣的可视化研究及其在富氧条件下的烧结特性研究[D]. 杭州: 浙江大学, 2015.
ZHOU Bin. Visualization research of fouling and slagging for inferior coal and its sintering behavior under oxy-fuel combustion atmosphere [D]. Hangzhou: Zhejiang University, 2015.
[24]   潘攀. 煤的结渣特性研究[D]. 北京: 华北电力大学, 2007.
PAN Pan. Slagging property research of coal [D]. Beijing: North China Electric Power University, 2007.
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