Modeling and reaction kinetics study on K capture by adsorbents in high temperature flue gas

doi:10.11949/j.issn.0438-1157.20181497

Abstract

Abstract:

Aiming at the performance description of using adsorbent to control the behavior of K-containing gas in flue gas during biomass combustion, the performance and influencing factors of kaolin and coal fly ash trapping KOH (K₂CO₃), KCl and K₂SO₄ were investigated by one-dimensional plug flow reactor model. After comparing the model calculations with the experimental measurements in the literature to verify the rationality of the model and to determine the kinetic parameters, the differences in the performance of kaolin and coal fly ash adsorbing various K-containing gases were compared. The results showed that employing the global kinetic model and a single set of kinetic parameters was capable of predicting the amount of K captured by kaolin and coal fly ash under a wide range of reaction conditions and the kinetic parameters determined were reasonable. Within the given ranges of K concentration and flue gas temperature, the patterns of K capture by kaolin and coal fly ash were similar, both increasing with the increase of flue gas temperature and K concentration, but the effect of K concentration on kaolin adsorption was more obvious. The capabilities of K adsorption by both kaolin and coal fly ash were: KOH > KCl > K₂SO₄, but the adsorption capability of kaolin was much stronger than coal fly ash.

Key words: biomass combustion, K-containing species control, sorbent, mathematical model, kinetics

摘要：

针对生物质燃烧时采用吸附剂控制烟气中含K气体成分行为的性能描述，采用一维柱塞流反应器模型探究高岭土和煤灰捕集KOH（K₂CO₃）、KCl和K₂SO₄的性能及影响因素。通过模型计算与文献实验值比较检验模型合理性和确定动力学参数，并比较高岭土和煤灰捕集不同含K成分的性能差异。结果表明，采用表观动力学模型和单一的动力学参数可预测广泛反应条件下高岭土和煤灰捕集K的量，所确定的动力学参数是合理的；在给定的K浓度和烟气温度范围内，单位质量高岭土和煤灰捕集K的规律相似，均随烟气温度的升高而增大，随K浓度的增大而增大，且高岭土捕集能力受K浓度影响更明显；高岭土和煤灰捕集K的能力均为KOH强于KCl，强于K₂SO₄，且高岭土捕集能力明显强于煤灰。

关键词: 生物质燃烧, 含K成分控制, 吸附剂, 数学模型, 动力学

CLC Number:

TK 16

Chuanjie ZHENG, Changdong SHENG. Modeling and reaction kinetics study on K capture by adsorbents in high temperature flue gas[J]. CIESC Journal, 2019, 70(6): 2259-2268.

郑传杰, 盛昌栋. 高温烟气中吸附剂捕集K的模型及其反应动力学研究[J]. 化工学报, 2019, 70(6): 2259-2268.

Figures/Tables 9

Table 1 Kinetic parameters of kaolin and coal fly ash adsorbing different K-containing gas species

	高岭土				煤灰
	KOH	K₂CO₃	KCl	K₂SO₄	KOH	KCl	K₂SO₄
k ₀×10^－8/(m³ gas/((m³ pore)·s))	3.8	3.8	2.3	1.57	0.21	0.11	0.094
E/(kJ/mol)	25.08	25.08	25.08	25.08	25.08	25.08	25.08

Fig.1 Comparison of model calculations and experimental measurements of KOH adsorption by kaolin at different temperatures and KOH concentrations

Fig.2 Comparison of model calculated and experiment measured K capture by kaolin at different initial KOH concentrations (at temperature of 1373 K and residence time of 1.2 s)

Fig.3 Comparison of model calculations and experiment measurements of K2CO3, KCl and K2SO4 adsorption by kaolin

Table 2 Model calculating conditions for kaolin adsorbing K2CO3, KCl and K2SO4

含K成分	? _K×10⁶	烟气温度T/K	停留时间t/s
K₂CO₃	50	1373	1.2
	250	1373	1.2
	500	1073、1173、1373、1573	1.2
	750	1373	1.2
	1000	1373	1.2
KCl	50	1573	1.0
	250	1573	1.0
	500	1073、1173、1373、1573	1.2(1573 K时1.0)
	750	1573	1.0
	1000	1573	1.0
K₂SO₄	50	1373	1.2
	250	1373	1.2
	500	1073、1173、1373、1573	1.2
	750	1373	1.2

Table 3 Physical and chemical properties of coal fly ash[31]

平均粒径/μm	BET表面积/(m²/g)	含量/%
平均粒径/μm	BET表面积/(m²/g)	SO₃	SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	Na₂O	K₂O	TiO₂	P₂O₅
10.2	8.04	0.52	37.98	42.61	6.68	5.08	1.31	0.59	1.69	1.18	2.36

Fig.4 Comparison of model calculations and experiment measurements of KOH and KCl adsorption by coal fly ash

Fig.5 Comparison of model calculations and experiment measurements of K2SO4 adsorption by coal fly ash at ? K of 5.0×10-4 and residence time of 1.2 s

Fig.6 Comparison of performance of KOH, KCl and K2SO4 adsorption between kaolin and coal fly ash

References 31

1	斯俊平 . 燃煤过程中钠对焦特性及细颗粒物控制的影响[D]. 武汉: 华中科技大学, 2014.
	Si J P . Effects of sodium on char characteristics and fine particulate matters control during coal combustion[D]. Wuhan: Huazhong University of Science and Technology, 2014.
2	黄忠友 . 试析生物质发电发展现状及前景[J]. 科技风, 2019, (2): 185.
	Huang Z Y . Analysis of current situation and prospect of biomass power generation[J]. Technology Wind, 2019, (2): 185.
3	徐林林 . 高岭土对高钠煤燃烧过程中碱金属的脱除效果研究[D]. 天津: 天津大学, 2015.
	Xu L L . Effect of kaolin on removal of alkali metals during combustion of high sodium coal[D]. Tianjin: Tianjin University, 2015.
4	Mcnallan M J , Yurek G J , Elliott J F . The formation of inorganic particulates by homogeneous nucleation in gases produced by the combustion of coal[J]. Combustion & Flame, 1981, 42(81): 45-60.
5	兰泽全, 曹欣玉, 周俊虎, 等 . 锅炉受热面沾污结渣的危害及其防治措施[J]. 电站系统工程, 2003, 19(1): 31-33.
	Lan Z Q , Cao X Y , Zhou J H , et al . Hazards and prevention measures of fouling and slagging on heating surfaces of boilers[J]. Power Plant System Engineering, 2003, 19(1): 31-33.
6	董雪玲 . 大气可吸入颗粒物对环境和人体健康的危害[J]. 资源·产业, 2004, (5): 52-55.
	Dong X L . Hazards of inhalable particulates to environment and human health[J]. Resources·Industry, 2004, (5): 52-55.
7	Zhan Z , Fry A R , Wendt J O L . Relationship between submicron ash aerosol characteristics and ash deposit compositions and formation rates during air- and oxy-coal combustion[J]. Fuel, 2016, 181: 1214-1223.
8	Waindich A , Müller M . Alkali removal at 1400℃ under gasification conditions[J]. Fuel, 2014, 116: 889-893.
9	Gibbs A R , Pooley F D . Analysis and interpretation of inorganic mineral particles in "lung" tissues[J]. Thorax, 1996, 51(3): 327-334.
10	周科 . 燃煤细微颗粒物生成特性与炉内控制的研究[D]. 武汉: 华中科技大学, 2011.
	Zhou K . Study on the generation characteristics and control of fine particles in coal combustion[D]. Wuhan: Huazhong University of Science and Technology, 2011.
11	温昶, 徐明厚, 于敦喜, 等 . 煤粉O₂/CO₂燃烧时PM_{2. 5}及其Fe、S的生成特性[J]. 化工学报, 2011, 62(4): 1062-1069.
	Wen C , Xu M H , Yu D X , et al . Formation characteristics of PM_{2. 5} including Fe, S during O₂/CO₂ combustion of pulverized coal[J]. CIESC Journal, 2011, 62(4): 1062-1069.
12	Quann R J , Sarofim A F . Vaporization of refractory oxides during pulverized coal combustion[J]. Symposium on Combustion, 1982, 19(1): 1429-1440.
13	Si J P , Liu X W , Xu M H , et al . Effect of kaolin additive on PM_{2. 5}, reduction during pulverized coal combustion: importance of sodium and its occurrence in coal[J]. Applied Energy, 2014, 114(2): 434-444.
14	Yan L , Gupta R P , Wall T F . The implication of mineral coalescence behaviour on ash formation and ash deposition during pulverised coal combustion[J]. Fuel, 2001, 80(9): 1333-1340.
15	徐明厚, 于敦喜, 刘小伟 . 燃煤可吸入颗粒物的形成与排放[M]. 北京: 科学出版社, 2009.
	Xu M H , Yu D X , Liu X W . Formation and Emission of Inhalable Particles from Coal Combustion[M]. Beijing: Science Press, 2009.
16	刘建忠, 张光学, 周俊虎, 等 . 燃煤细灰的形成及微观形态特征[J]. 化工学报, 2006, 57(12): 2976-2980.
	Liu J Z , Zhang G X , Zhou J H , et al . Formation and micromorphology characteristics of fine particles generated during coal combustion [J]. Journal of Chemical Industry and Engineering(China), 2006, 57(12): 2976-2980.
17	刘勇, 赵汶, 刘瑞, 等 . 化学团聚促进电除尘脱除PM_{2. 5}的实验研究[J]. 化工学报, 2014, 65(9): 3609-3616.
	Liu Y , Zhao W , Liu R , et al . Improving removal of PM_2.5 by electrostatic precipitator with chemical agglomeration[J]. CIESC Journal, 2014, 65(9): 3609-3616.
18	Quann R J . Ash vaporization under simulated pulverized coal combustion conditions[D]. Massachusetts: Massachusetts Institute of Technology, 1982.
19	Li Y , Raj G A , Wall T . Fragmentation behavior of pyrite and calcite during high-temperature processing and mathematical simulation[J]. Energy & Fuels, 2001, 15(2): 389-394.
20	Quann R J , Neville M , Janghorbani M , et al . Mineral matter and trace-element vaporization in a laboratory-pulverized coal combustion system[J]. Environmental Science & Technology, 1982, 16(11): 776.
21	Helble J J . Mechanisms of ash particle formation and growth during pulverized coal combustion[D]. Massachusetts: MIT Library in America, 1987.
22	孙伟, 刘小伟, 徐义书, 等 . 两种改性高岭土减排超细颗粒物的对比分析[J]. 化工学报, 2016, 67(4): 1179-1185.
	Xun W , Liu X W , Xu Y S , et al . Contrastive analysis of reducing ultrafine particulate matters emission by two modified kaolin[J]. CIESC Journal, 2016, 67(4): 1179-1185.
23	Mwabe P O , Wendt J O L . Mechanisms governing trace sodium capture by kaolinite in a downflow combustor[J]. Symposium on Combustion, 1996, 26(2): 2447-2453.
24	Wang G L , Jensen P A , Wu H , et al . Potassium capture by kaolin (1): KOH[J]. Energy & Fuels, 2018, 32(2): 1851-1862.
25	Schürmann H , Unterberger S , Hein K R , et al . The influence of fuel additives on the behaviour of gaseous alkali-metal compounds during pulverised coal combustion[J]. Faraday Discussions, 2001, 119(119): 433-444.
26	Gale T , Wendt J L . Mechanisms and models describing sodium and lead scavenging by a kaolinite aerosol at high temperatures[J]. Aerosol Science & Technology, 2003, 37(11): 865-876.
27	Wang G L , Jensen P A , Wu H , et al . Potassium capture by kaolin (2): K₂CO₃, KCl, and K₂SO₄ [J]. Energy & Fuels, 2018, 32(3): 3566-3578.
28	Damoe A J , Wu H , Frandsen F J , et al . Impact of coal fly ash addition on combustion aerosols (PM_{2. 5}) from full-scale suspension-firing of pulverized wood[J]. Energy & Fuels, 2014, 28(5): 3217-3223.
29	Scandrett L A , Clift R . The thermodynamics of alkali removal from coal derived gases[J]. Journal of the Institute of Energy, 1984, 57 (433): 391-397.
30	Li Y , Li J , Jin Y , et al . Study on alkali-metal vapor removal for high-temperature cleaning of coal gas[J]. Energy & Fuels, 2005, 19(4): 1606-1610.
31	Wang G L . Potassium capture by kaolin and coal fly ash[D]. Kongens Lyngby: Technical University of Denmark, 2018.

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