Effects of anchor frame impeller structure on flow field in stirred tank during gasification slag activation

doi:10.16085/j.issn.1000-6613.2024-2008

Abstract

Abstract:

During the hydrochloric acid activation process of gasification slag, the generation of silica gel affects the overall mass transfer, necessitating the clarification of flow field distribution to optimize the reactor. This study constructs a 3000L reactor model and employs computational fluid dynamics to investigate the effects of impeller structure parameters and operating conditions on flow field characteristics. Using gasification slag activation slurry as the mixing medium, the SST k-ω model and Eulerian model are applied to analyze the effects of anchor frame impeller structure parameters and conditions on the specific power input, effective mixing volume fraction, and mixing time during stirring, through the multiple reference frame method and tracer concentration method. The results show that the anchor frame impeller is suitable for mixing gasification slag slurry, with the staggered anchor frame impeller exhibiting the strongest mixing capability. The changes in impeller diameter and rotation speed significantly affect the flow field distribution, with a 1320mm impeller diameter achieving a good balance between mixing efficiency and energy consumption. Increasing the rotation speed significantly enhances volumetric power density and effective mixing volume fraction, with an optimal operating speed of 20r/min, and the optimal installation height of impellers is 216mm. Under optimal design, rapid mixing of slurry is achieved at a low power consumption of 46.96W/m³.

Key words: reactors, non-Newtonian fluids, mixing, computational fluid dynamics (CFD), two-phase flow

摘要：

煤气化渣活化过程中硅酸成胶影响整体传质，需通过了解流场分布来优化反应器。本文构建容积3000L搪玻璃反应釜模型，通过计算流体力学方法研究搅拌桨叶结构参数和工况对流场特性的影响。以煤气化渣活化浆料为搅拌介质，使用剪切应力传输（SST）k-ω模型与Eulerian模型，通过多重参考系法和示踪剂浓度法分析锚框式桨叶结构参数与工况对搅拌过程中单位体积搅拌功率、有效搅拌体积分数和混合时间的影响。结果表明，锚框式桨叶适用于煤气化渣浆液的混合搅拌，其中错位锚框式桨搅拌下流速分布最均匀。桨径和转速的变化显著影响流场分布，1320mm桨径在混合效果与能耗之间达到较好的平衡，而转速的增加显著提高单位体积功率和有效搅拌体积分数，最佳运行转速为20r/min，最佳离底高度为216mm，最优设计下，桨以46.96W/m³的低功耗快速混合浆液。

关键词: 反应器, 非牛顿流体, 混合, 计算流体力学, 两相流

CLC Number:

TQ027.1

XU Wenjun, ZHANG Jianbo, GUO Yanxia, LI Huiquan, LI Shaopeng, REN Yiling. Effects of anchor frame impeller structure on flow field in stirred tank during gasification slag activation[J]. Chemical Industry and Engineering Progress, 2025, 44(8): 4463-4477.

续文钧, 张建波, 郭彦霞, 李会泉, 李少鹏, 任艺凌. 锚框式桨结构参数对煤气化渣活化过程流场特性的影响[J]. 化工进展, 2025, 44(8): 4463-4477.

Figures/Tables 30

References 39

[1]	高海洋, 梁龙, 靳开宇, 等. 煤气化渣资源化利用综述[J]. 煤炭科学技术, 2024, 52(8): 192-208.
	GAO Haiyang, LIANG Long, JIN Kaiyu, et al. Review on resource utilization of coal gasification slag[J]. Coal Science and Technology, 2024, 52(8): 192-208.
[2]	李翔宇, 李旭, 樊盼盼, 等. 利用脱碳气化渣矿化封存CO₂制备碳酸钙的影响研究[J]. 燃料化学学报(中英文), 2024, 52(8): 1193-1202.
	LI Xiangyu, LI Xu, FAN Panpan, et al. Study on the impact of using decarbonized gasification slag for CO₂ mineralization and storage to prepare calcium carbonate[J]. Journal of Fuel Chemistry and Technology, 2024, 52(8): 1193-1202.
[3]	LIU Shuo, CHEN Xingtong, AI Weidong, et al. A new method to prepare mesoporous silica from coal gasification fine slag and its application in methylene blue adsorption[J]. Journal of Cleaner Production, 2019, 212: 1062-1071.
[4]	胡文豪, 张建波, 李少鹏, 等. 煤气化渣制备聚合氯化铝工艺研究[J]. 洁净煤技术, 2019, 25(1): 154-159.
	HU Wenhao, ZHANG Jianbo, LI Shaopeng, et al. Study on the preparation of polyaluminium chloride from coal gasification residue[J]. Clean Coal Technology, 2019, 25(1): 154-159.
[5]	QU Jiangshan, ZHANG Jianbo, LI Huiquan, et al. A high value utilization process for coal gasification slag: Preparation of high modulus sodium silicate by mechano-chemical synergistic activation[J]. Science of The Total Environment, 2021, 801: 149761.
[6]	马小路, 袁梦霞, 乔秀臣. 活化煤气化粗渣盐酸浸取机理研究[J]. 无机盐工业, 2016, 48(12): 64-67, 80.
	MA Xiaolu, YUAN Mengxia, QIAO Xiuchen. Hydrochloric acid leaching mechanism of activated coarse coal gasification slag[J]. Inorganic Chemicals Industry, 2016, 48(12): 64-67, 80.
[7]	ZHAO Longsheng, WANG Lina, QI Tao, et al. Leaching of titanium and silicon from low-grade titanium slag using hydrochloric acid leaching[J]. JOM, 2018, 70(10): 1985-1990.
[8]	胡文豪. 煤气化渣铝硅组分活化分离与资源化利用基础研究[D]. 北京: 中国科学院大学(中国科学院过程工程研究所), 2019.
	HU Wenhao. Basic study on activation separation and resource utilization of aluminum and silicon components in coal gasification slag[D]. Beijing: Institute of Process Engineering, Chinese Academy of Sciences, 2019.
[9]	文英明. 基于DEM-VOF的搅拌釜内气-液-固三相流传输及稀土浸出特性研究[D]. 赣州: 江西理工大学, 2024.
	WEN Yingming. Study on gas-liquid-solid three-phase flow transfer and rare earth leaching characteristics in stirred tank based on DEM-VOF[D]. Ganzhou: Jiangxi University of Science and Technology, 2024.
[10]	KAZEMZADEH Argang, Farhad EIN-MOZAFFARI, LOHI Ali, et al. Investigation of hydrodynamic performances of coaxial mixers in agitation of yield-pseudoplasitc fluids: Single and double central impellers in combination with the anchor[J]. Chemical Engineering Journal, 2016, 294: 417-430.
[11]	PAKZAD Leila, Farhad EIN-MOZAFFARI, UPRETI Simant R, et al. Agitation of Herschel-Bulkley fluids with the Scaba-anchor coaxial mixers[J]. Chemical Engineering Research and Design, 2013, 91(5): 761-777.
[12]	BAO Yuyun, YANG Bo, XIE Yong, et al. Power demand and mixing performance of coaxial mixers in non-Newtonian fluids[J]. Journal of Chemical Engineering of Japan, 2011, 44(2): 57-66.
[13]	AYALA Jenniffer Solange, DE MOURA Helder Lima, DE LIMA AMARAL Rodrigo, et al. Two-dimensional shear rate field and flow structures of a pseudoplastic fluid in a stirred tank using particle image velocimetry[J]. Chemical Engineering Science, 2022, 248: 117198.
[14]	苏杨, 虞培清, 黄志坚. 搅拌技术在聚合反应釜中应用[J]. 化学推进剂与高分子材料, 2003, 1(4): 19-23.
	SU Yang, YU Peiqing, HUANG Zhijian. Applications of mixing technique in polymerization reaction kettle[J]. Chemical Propellants & Polymeric Materials, 2003, 1(4): 19-23.
[15]	ZADGHAFFARI R, MOGHADDAS J S, REVSTEDT J. Large-eddy simulation of turbulent flow in a stirred tank driven by a Rushton turbine[J]. Computers & Fluids, 2010, 39(7): 1183-1190.
[16]	RANADE V V, BOURNE J R, JOSHI J B. Fluid mechanics and blending in agitated tanks[J]. Chemical Engineering Science, 1991, 46(8): 1883-1893.
[17]	汪晶. 多层轴流桨搅拌槽内非牛顿流体气液传质特性研究[D]. 北京: 北京化工大学, 2022.
	WANG Jing. Study on gas-liquid mass transfer characteristics of non-Newtonian fluid in stirred tank with multi-layer axial impeller[D]. Beijing: Beijing University of Chemical Technology, 2022.
[18]	CHACHI Mohamed, KAMLA Youcef, ALHAFFAR Mouheddin T, et al. Quantitative assessment of agitator performance in an anchor-stirred tank: Investigating the impact of geometry, eccentricity, and rheological characteristics[J]. Arabian Journal for Science and Engineering, 2024, 49(10): 13885-13895.
[19]	王宏. 假塑性流体搅拌流场混沌特征及混合特性[D]. 青岛: 青岛科技大学, 2021.
	WANG Hong. Chaotic and stiring characteristics of flow field of pseudoplastic fluid[D]. Qingdao: Qingdao University of Science and Technology, 2021.
[20]	栾德玉. 错位桨搅拌假塑性流体流动与混合特性研究[D]. 济南: 山东大学, 2012.
	LUAN Deyu. Study on flow and mixing characteristics of pseudoplastic fluid stirred by staggered paddles[D]. Jinan: Shandong University, 2012.
[21]	METZNER A B, REED J C. Flow of non-Newtonian fluids—Correlation of the laminar, transition, and turbulent-flow regions[J]. AIChE Journal, 1955, 1(4): 434-440.
[22]	刘树磊. 搅拌釜内非牛顿流体的流动与传热数值分析[D]. 上海: 东华大学, 2022.
	LIU Shulei. Numerical analysis of flow and heat transfer of non-Newtonian fluid in stirred tank[D]. Shanghai: Donghua University, 2022.
[23]	MENTER F R. Influence of freestream values on k-omega turbulence model predictions[J]. AIAA Journal, 1992, 30(6): 1657-1659.
[24]	SONG Xijie, YAO Rao, SHEN Yubin, et al. Numerical prediction of erosion based on the solid-liquid two-phase flow in a double-suction centrifugal pump[J]. Journal of Marine Science and Engineering, 2021, 9(8): 836.
[25]	Artur WODOŁAŻSKI, SKIBA Jacek, ZAREBSKA Katarzyna, et al. CFD Modeling of the catalyst oil slurry hydrodynamics in a high pressure and temperature as potential for biomass liquefaction[J]. Energies, 2020, 13(21): 5694.
[26]	GEORGOULAS Anastasios N, ANGELIDIS Panagiotis B, PANAGIOTIDIS Theologos G, et al. 3D numerical modelling of turbidity currents[J]. Environmental Fluid Mechanics, 2010, 10(6): 603-635.
[27]	常少华. 不同流动结构对污染物絮凝去除的研究[D]. 南京: 南京信息工程大学, 2023.
	CHANG Shaohua. Study on the effects of different flow structures on pollutant removal via flocculation[D]. Nanjing: Nanjing University of Information Science and Technology, 2023.
[28]	房洪芹. 双层斜叶组合桨搅拌槽内流体流场的数值模拟及PIV试验研究[D]. 镇江: 江苏大学, 2020.
	FANG Hongqin. Numerical simulation and PIV experimental study on fluid flow field in stirred tank with double-layer inclined blade combined impeller[D]. Zhenjiang: Jiangsu University, 2020.
[29]	MICHELETTI Martina, NIKIFORAKI Loukia, LEE Kalok C, et al. Particle concentration and mixing characteristics of moderate-to-dense solid-liquid suspensions[J]. Industrial & Engineering Chemistry Research, 2003, 42(24): 6236-6249.
[30]	HIRATA Yushi, NIENOW Alvin W, MOORE Iain P T. Estimation of cavern sizes in a shear-thinning plastic fluid agitated by a Rushton turbine based on LDA measurements[J]. Journal of Chemical Engineering of Japan, 1994, 27(2): 235-237.
[31]	AMANULLAH A, HJORTH S A, NIENOW A W. A new mathematical model to predict cavern diameters in highly shear thinning, power law liquids using axial flow impellers[J]. Chemical Engineering Science, 1998, 53(3): 455-469.
[32]	许言, 王健, 武永军, 等. 多叶片组合式搅拌桨釜内流动特性和混合性能研究[J]. 化工学报, 2020, 71(11): 4964-4970.
	XU Yan, WANG Jian, WU Yongjun, et al. Study on the flow characteristics and mixing performance of multi-blade combined agitator[J]. CIESC Journal, 2020, 71(11): 4964-4970.
[33]	PRAJAPATI P, EIN-MOZAFFARI F. CFD Investigation of the mixing of yield-pseudoplastic fluids with anchor impellers[J]. Chemical Engineering & Technology, 2009, 32(8): 1211-1218.
[34]	伍熙, 姜帅, 杜玮, 等. 双层错位穿流桨槽内流场分析及设计优化[J]. 重庆理工大学学报(自然科学), 2025, 39(2): 195-201.
	WU Xi, JIANG Shuai, DU Wei, et al. Analysis and design optimization of flow field in double-layer dislocated-punched impeller groove[J]. Journal of Chongqing University of Technology (Natural Science), 2025, 39(2): 195-201.
[35]	贺钰. 非牛顿流体卡波姆的流变特性及流体混合性能数值模拟[D]. 长沙: 中南大学, 2023.
	HE Yu. Study of Carbomer rheological properties of non-Newtonian fluids and numerical simulation offluid mixing properties[D]. Changsha: Central South University, 2023.
[36]	MONTANTE Giuseppina, Michal MOŠTĚK, JAHODA Milan, et al. CFD simulations and experimental validation of homogenisation curves and mixing time in stirred Newtonian and pseudoplastic liquids[J]. Chemical Engineering Science, 2005, 60(8/9): 2427-2437.
[37]	LIU Li, BARIGOU Mostafa. Numerical modelling of velocity field and phase distribution in dense monodisperse solid-liquid suspensions under different regimes of agitation: CFD and PEPT experiments[J]. Chemical Engineering Science, 2013, 101: 837-850.
[38]	FAN Yuewei, WANG Shibo, WANG Hua, et al. Formation mechanism and chaotic reinforcement elimination of the mechanical stirring isolated mixed region[J]. International Journal of Chemical Reactor Engineering, 2021, 19(3): 239-250.
[39]	HASHIMOTO Shunsuke, ITO Hiroyuki, INOUE Yoshiro. Experimental study on geometric structure of isolated mixing region in impeller agitated vessel[J]. Chemical Engineering Science, 2009, 64(24): 5173-5181.

桨叶	D/mm	θ/(°)	t₁×t₂	h/mm	h₃/mm	d_N /mm	h₄/mm	d₁/mm	d₂/mm
A	1440	—	97mm×50mm	130	800	97	0	—	—
B	1440	75	97mm×50mm	130	800	97	168	—	—
C	1440	90	97mm×50mm	130	847.5	97	0	335.75	—
D	1440	90	97mm×50mm	130	847.5	97	0	—	376.25
E	1440	90	97mm×50mm	130	847.5	97	72.5	—	376.25

桨叶	D/mm	θ/(°)	t₁×t₂	h/mm	h₃/mm	d_N /mm	h₄/mm	d₁/mm	d₂/mm
A	1440	—	97mm×50mm	130	800	97	0	—	—
B	1440	75	97mm×50mm	130	800	97	168	—	—
C	1440	90	97mm×50mm	130	847.5	97	0	335.75	—
D	1440	90	97mm×50mm	130	847.5	97	0	—	376.25
E	1440	90	97mm×50mm	130	847.5	97	72.5	—	376.25

桨型	P_V /W·m^-3	有效搅拌体积分数/%
A	63.135	67.98
B	74.152	98.02
C	85.200	97.65
D	86.948	98.02
E	59.726	99.15

桨型	P_V /W·m^-3	有效搅拌体积分数/%
A	63.135	67.98
B	74.152	98.02
C	85.200	97.65
D	86.948	98.02
E	59.726	99.15

D/mm	P_V /W·m^-3	有效搅拌体积分数/%
980	23.118	62.92
1080	28.442	78.73
1180	35.397	94.74
1320	45.530	99.77
1440	59.726	99.15