Experimental Study on Sintering and Melting Characteristics and Mineral Transformation Law of Synthetic Biomass Ash

doi:10.12096/j.2096-4528.pgt.23162

Abstract

Abstract:

Objective The coking problem of biomass in fluidized bed combustion process was studied, and the influence of potassium salt form and content on the sintering and melting characteristics of biomass ash was analyzed. Methods The sintering and melting characteristics and the mineral transformation law of synthetic biomass ash were analyzed by experiments with scanning electron microscope coupled energy dispersive spectrometer, X-ray diffractometer, X-ray fluorescence, and FactSage thermodynamic calculation software. Results In the typical operating temperature range of 750-950 ℃, the sintering and melting degree of synthetic biomass ash aggravates with the increase of temperature and potassium salt mass fraction. In addition, the effects of different forms of potassium salt on the sintering and melting characteristics of biomass synthetic ash are also significantly different. When the potassium salt is in the form of K₂CO₃, the liquid phase in the synthetic ash could reach up to 34.36%, leading consequently to severe sintering of the ash. When the potassium salt is in the form of KCl, most of K and Cl elements escape at 750-850 ℃, and the sintering degree of synthetic ash is weakened in comparison with the K₂CO₃ situation. When the potassium salt is in the form of K₂SO₄, the liquid phase in the synthetic ash is the least, and the sintering and melting degree is also the weakest. Conclusion Changing the form of potassium salt and controlling the temperature of fluidized bed are expected to alleviate the coking problem of biomass in fluidized bed combustion.

Key words: biomass, fluidized bed, synthetic ash, sintering and melting, potassium salt

CLC Number:

TK 62

Yongjun LUO, Jianbo LI, Hongyan ZHU. Experimental Study on Sintering and Melting Characteristics and Mineral Transformation Law of Synthetic Biomass Ash[J]. Power Generation Technology, 2024, 45(4): 600-610.

Figures/Tables 23

References 32

1	郑妍，姚宣，陈训强．生物质气化耦合发电体系的合成气组分与能量分析[J]．发电技术，2023，44(6)：859-864． doi:10.12096/j.2096-4528.pgt.22164
	ZHENG Y， YAO X， CHEN X Q ．Analysis of syngas components and energy in biomass gasification coupled power generation system[J]．Power Generation Technology，2023，44(6)：859-864． doi:10.12096/j.2096-4528.pgt.22164
2	张政林，张惠娟，孙文治，等．基于改进旗鱼算法的综合能源系统能量管理[J]．电力系统保护与控制，2022，20(22)：142-151．
	ZHENG Z L， ZHANG H J， SUN W Z，et al ．Energy management of an integrated energy system based on an improved sailed fish optimizer algorithm[J]．Power System Protection and Control，2022，20(22)：142-151．
3	LV Y， NIU Y， LIANG Y，et al ．Experiment and kinetics studies on ash fusion characteristics of biomass/coal mixtures during combustion[J]．Energy & Fuels，2019，33(10)：10317-10323． doi:10.1021/acs.energyfuels.9b02563
4	SAIDUR R， ABDELAZIZ E A， DEMIRBAS A，et al ．A review on biomass as a fuel for boilers[J]．Renewable and Sustainable Energy Reviews，2011，15(5)：2262-2289． doi:10.1016/j.rser.2011.02.015
5	臧海祥，马铭欣，周亦洲，等．电力市场环境下风电-光热-生物质混合电站鲁棒优化调度模型[J]．电力系统保护与控制，2022，50(5)：1-11．
	ZANG H X， MA M X， ZHOU Y Z，et al ．Robust optimal scheduling model for a ‘wind power-concentrating solar power-biomass’ hybrid power plant in the electricity market[J]．Power System Protection and Control，2023，44(3)：1-14．
6	王永利，韩煦，刘晨，等．基于生-光耦合利用的乡村电-热综合能源系统规划[J]．电力建设，2023，44(3)：1-14．
	WANG Y L， HAN X， LIU C，et al ．Rural electricity-heat integrated energy system planning based on coupling utilization of biomass and solar resources[J]．Electric Power Construction，2023，44(3)：1-14．
7	薛凯，王义函，陈衡，等．槽式太阳能辅助生物质热电联产系统热力学性能分析[J]．发电技术，2021，42(6)：653-664． doi:10.12096/j.2096-4528.pgt.21044
	XUE K， WANG Y H， CHEN H，et al ．Thermodynamic performance analysis of a parabolic trough solar-assisted Biomass-fired cogeneration system[J]．Power Generation Technology，2021，42(6)：653-664． doi:10.12096/j.2096-4528.pgt.21044
8	朱骏杰，管俊豪，岳子尧，等．燃煤机组直接耦合生物质的模型构建与碳减排分析[J]．内蒙古电力技术，2023，41(6)：17-25．
	ZHU J J， GUAN J H， YUE Z Y，et al ．Model construction and carbon emission reduction analysis of direct coupling of biomass in coal-fired unit[J]．Inner Mongolia Electric Power，2023，41(6)：17-25．
9	LI Q H， ZHANG Y G， MENG A H，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
10	VASSILEV S V， BAXTER D， VASSILEVA C G ．An overview of the behaviour of biomass during combustion：part II．Ash fusion and ash formation mechanisms of biomass types[J]．Fuel，2014，117：152-183． doi:10.1016/j.fuel.2013.09.024
11	MA T， FAN C， HAO L，et al ．Fusion characterization of biomass ash[J]．Thermochimica Acta，2016，638：1-9． doi:10.1016/j.tca.2016.06.008
12	SHAO Y， WANG J， PRETO F，et al ．Ash deposition in biomass combustion or co-firing for power/heat generation[J]．Energies，2012，5(12)：5171-5189． doi:10.3390/en5125171
13	LI G， LI S， XU X，et al ．Dynamic behavior of biomass ash deposition in a 25 kW one-dimensional down-fired combustor[J]．Energy & Fuels，2014，28(1)：219-227． doi:10.1021/ef401530a
14	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
15	NIU Y， TAN H， HUI S E ．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
16	李定青，王鹏，姜春光，等．采用添加剂抑制生物质锅炉受热面沉积试验分析[J]．内蒙古电力技术，2023，41(1)：87-92．
	LI D Q， WANG P， JIANG C G，et al ．Experimental analysis of using additive to inhibit heating surface deposition in biomass-fired boiler[J]．Inner Mongolia Electric Power，2023，41(1)：87-92．
17	马隆龙．生物质能利用技术的研究及发展[J]．化学工业，2007，25(8)：9-14． doi:10.3969/j.issn.1673-9647.2007.08.002
	MA L L ．Process technology of bio-energy utilization and its development[J]．Chemical Industry，2007，25(8)：9-14． doi:10.3969/j.issn.1673-9647.2007.08.002
18	王朝华．对我国生物质能源发展现状和趋势的分析[J]．农业经济，2011(10)：12-14． doi:10.3969/j.issn.1001-6139.2011.10.004
	WANG Z H ．Analysis on the present situation and trend of biomass energy development in China[J]．Agricultural Economy，2011(10)：12-14． doi:10.3969/j.issn.1001-6139.2011.10.004
19	EASTERLY J L， BURNHAM M ．Overview of biomass and waste fuel resources for power production[J]．Biomass and Bioenergy，1996，10(2/3)：79-92． doi:10.1016/0961-9534(95)00063-1
20	VASSILEV S V， VASSILEVA C G， VASSILEV V S ．Advantages and disadvantages of composition and properties of biomass in comparison with coal：an overview[J]．Fuel，2015，158：330-350． doi:10.1016/j.fuel.2015.05.050
21	VASSILEV S V， BAXTER D， ANDERSEN L K，et al ．An overview of the composition and application of biomass ash：potential utilisation，technological and ecological advantages and challenges[J]．Fuel，2013，105：19-39． doi:10.1016/j.fuel.2012.10.001
22	LANE D J， VAN EYK P J， ASHMAN P J，et al ．Release of Cl，S，P，K，and Na during thermal conversion of algal biomass[J]．Energy & Fuels，2015，29(4)：2542-2554． doi:10.1021/acs.energyfuels.5b00279
23	方江涛，廖艳芬，黄泽浩，等．中国南方典型农业生物质结渣特性实验研究[J]．新能源进展，2014，2(4)：275-281． doi:10.3969/j.issn.2095-560X.2014.04.006
	FANG J T， LIAO Y F， HUANG Z H，et al ．Experimental study on slagging characteristics of typical agricultural biomass in South China[J]．Advances in New and Renewable Energy，2014，2(4)：275-281． doi:10.3969/j.issn.2095-560X.2014.04.006
24	DU S， YANG H， QIAN K，et al ．Fusion and transformation properties of the inorganic components in biomass ash[J]．Fuel，2014，117：1281-1287． doi:10.1016/j.fuel.2013.07.085
25	NÄZELIUS I L， FAGERSTRÖM J， BOMAN C，et al ．Slagging in fixed-bed combustion of phosphorus-poor biomass：critical ash-forming processes and compositions[J]．Energy & Fuels，2015，29(2)：894-908． doi:10.1021/ef502531m
26	WU Y， WU S， LI Y，et al ．Physico-chemical characteristics and mineral transformation behavior of ashes from crop straw[J]．Energy & Fuels，2009，23(10)：5144-5150． doi:10.1021/ef900496b
27	JIANG J，TIE Y， DENG L，et al ．Influence of water-washing pretreatment on ash fusibility of biomass[J]．Renewable Energy，2022，200：125-135． doi:10.1016/j.renene.2022.09.121
28	CHEN X D， KONG L-X， BAI J，et al ．Study on fusibility of coal ash rich in sodium and sulfur by synthetic ash under different atmospheres[J]．Fuel，2017，202：175-183． doi:10.1016/j.fuel.2017.04.001
29	岑可法．锅炉和热交换器的积灰、结渣、磨损和腐蚀的防止原理与计算[M]．北京：科学出版社，1994．
	CEN K F ．Prevention principle and calculation of ash accumulation，slagging，wear and corrosion of boilers and heat exchangers[M]．Beijing：Science Press，1994．
30	KNUDSEN J N， JENSEN P A， DAM-JOHANSEN K ．Transformation and release to the gas phase of Cl，K，and S during combustion of annual biomass[J]．Energy & Fuels，2004，18(5)：1385-1399． doi:10.1021/ef049944q
31	SEVONIUS C， YRJAS P， HUPA M ．Defluidization of a quartz bed-Laboratory experiments with potassium salts[J]．Fuel，2014，127：161-168． doi:10.1016/j.fuel.2013.10.047
32	刘卓，李建波，龙潇飞，等．循环流化床燃烧高钠准东煤的床料颗粒聚团特性[J]．中国电机工程学报，2022，42(6)：2248-2258．
	LIU Z， LI J B， LONG X F，et al ．Bed particle agglomeration in circulating fluidized bed burning high-sodium Zhundong coal[J]．Proceedings of the CSEE，2022，42(6)：2248-2258．

样品	化学成分质量分数/%
样品	SiO₂	CaO	MgO	Al₂O₃	Fe₂O₃	Na₂SO₄
1	7.50	69.16	6.78	2.50	2.03	4.65
2	7.50	60.50	5.94	2.50	1.78	4.08
3	7.50	43.22	4.24	2.50	1.27	3.96
4	7.50	69.16	6.78	2.50	2.03	4.65
5	7.50	60.50	5.94	2.50	1.78	4.08
6	7.50	43.22	4.24	2.50	1.27	3.96
7	7.50	69.16	6.78	2.50	2.03	4.65
8	7.50	60.50	5.94	2.50	1.78	4.08
9	7.50	43.22	4.24	2.50	1.27	3.96
10	37.50	34.58	3.39	12.50	1.02	2.34
11	37.50	25.94	2.54	12.50	0.76	1.74
12	37.50	8.65	0.85	12.50	0.25	0.57
13	37.50	34.58	3.39	12.50	1.02	2.34
14	37.50	25.94	2.54	12.50	0.76	1.74
15	37.50	8.65	0.85	12.50	0.25	0.57
16	37.50	34.58	3.39	12.50	1.02	2.34
17	37.50	25.94	2.54	12.50	0.76	1.74
18	37.50	8.65	0.85	12.50	0.25	0.57

样品	化学成分质量分数/%
样品	SiO₂	CaO	MgO	Al₂O₃	Fe₂O₃	Na₂SO₄
1	7.50	69.16	6.78	2.50	2.03	4.65
2	7.50	60.50	5.94	2.50	1.78	4.08
3	7.50	43.22	4.24	2.50	1.27	3.96
4	7.50	69.16	6.78	2.50	2.03	4.65
5	7.50	60.50	5.94	2.50	1.78	4.08
6	7.50	43.22	4.24	2.50	1.27	3.96
7	7.50	69.16	6.78	2.50	2.03	4.65
8	7.50	60.50	5.94	2.50	1.78	4.08
9	7.50	43.22	4.24	2.50	1.27	3.96
10	37.50	34.58	3.39	12.50	1.02	2.34
11	37.50	25.94	2.54	12.50	0.76	1.74
12	37.50	8.65	0.85	12.50	0.25	0.57
13	37.50	34.58	3.39	12.50	1.02	2.34
14	37.50	25.94	2.54	12.50	0.76	1.74
15	37.50	8.65	0.85	12.50	0.25	0.57
16	37.50	34.58	3.39	12.50	1.02	2.34
17	37.50	25.94	2.54	12.50	0.76	1.74
18	37.50	8.65	0.85	12.50	0.25	0.57

等级	类别	特征
0	附着灰	无黏聚特征，灰粒间呈松散堆积状
1	微黏聚灰渣	已有灰粒的黏聚特征，易刮除，呈疏松状
2	弱黏聚灰渣	有一定的黏聚特征，较易刮除，有一定硬度
3	黏聚灰渣	黏聚在一起，硬度比强黏聚灰渣弱，较难刮除
4	强黏聚灰渣	硬度较大，无法完全刮除，不规则地黏聚硬渣
5	黏熔灰渣	由全熔融和半熔融渣组成，二者之间无法分开
6	熔融灰渣	全熔融，残灰表面被流渣覆盖，内部泡状结构

等级	类别	特征
0	附着灰	无黏聚特征，灰粒间呈松散堆积状
1	微黏聚灰渣	已有灰粒的黏聚特征，易刮除，呈疏松状
2	弱黏聚灰渣	有一定的黏聚特征，较易刮除，有一定硬度
3	黏聚灰渣	黏聚在一起，硬度比强黏聚灰渣弱，较难刮除
4	强黏聚灰渣	硬度较大，无法完全刮除，不规则地黏聚硬渣
5	黏熔灰渣	由全熔融和半熔融渣组成，二者之间无法分开
6	熔融灰渣	全熔融，残灰表面被流渣覆盖，内部泡状结构

温度/℃	矿物质量分数/%						熔融相比例/%
温度/℃	KAlSiO₄-HT	(Na, K)₂Si₂O₅	菱硅钙钠石(Na₄Ca₄Si₆O₁₈)	K₂Ca₂Si₂O₇	K₂Ca₆Si₄O₁₅	钙铁榴石(Ca₃Fe₂Si₃O₁₂)	熔融相比例/%
750	52.40	21.02	1.14	19.13	5.40	0.92	0
850	50.71	0	2.06	18.66	5.13	0.88	22.55
950	47.42	0	0	17.40	0	0.82	34.36