基于时变性聚团识别方法的高密度循环流化床内聚团分布特性

摘要为研究高密度提升管内的聚团分布特性,在18 m高循环流化床提升管系统中测定了不同固体循环速率下(G_s=100~1800 kg·m^-2·s^-1)的瞬时颗粒浓度。采用基于时变性的聚团识别方法对聚团进行识别,进而得到了聚团浓度、聚团持续时间和聚团速度在提升管中的分布。研究结果表明,高密度循环流化床中的颗粒浓度和聚团特性参数和与低密度循环流化床相比存在较大差异。高密度条件下,提升管内聚团浓度最高可达0.41。聚团持续时间最高可达5.5 ms。提升管截面内的聚团净向上运动,r/R=0.949时,聚团的净运动速度高达1.83 m·s^-1。此外,在极高的颗粒循环速率下(G_s=1800 kg·m^-2·s^-1),聚团特性参数的轴径向分布变得更均匀。

	Service

	把本文推荐给朋友
	加入我的书架
	加入引用管理器
	Email Alert
	RSS
	作者相关文章
	宋大山
	李之辉
	苏鑫
	王成秀
	蓝兴英
	高金森

关键词：高密度颗粒浓度聚团识别时变阈值聚团分布

Abstract： To investigate the characteristics of clusters within a high-density riser, measurements of the transient solids holdup were carried out at different solids circulation rates(G_s=100~1800 kg·m^-2·s^-1) in an 18 m high circulating fluidized bed riser. Clusters were identified by a time-varying threshold with cluster solids holdup, cluster duration time and cluster velocity. Results indicated that time-averaged solids holdup and cluster characteristics in the high-density circulating fluidized bed were significantly different from those in low-density circulating fluidized bed. At high density conditions, cluster solids holdup was higher up to 0.41. Cluster duration time was up to 5.5 ms. All clusters had a net upward movement with the velocity up to 1.83 m·s^-1 at r/R=0.949. Moreover, the axial and radial distribution of the cluster was even at high solids circulation rate with G_s up to 1800 kg·m^-2·s^-1.

Keywords： high-density solids holdup cluster identification time varying threshold cluster distribution

Received 2023-11-15;

Fund:国家自然科学基金面上项目(21978320);国家自然科学基金创新群体项目(22021004)。

Corresponding Authors: 王成秀,副教授,E-mail:cwang1277@cup.edu.cn。 Email: cwang1277@cup.edu.cn

About author: 宋大山(1999-),男,硕士研究生,研究方向为流态化技术与多相流反应工程。

引用本文:

宋大山, 李之辉, 苏鑫, 王成秀, 蓝兴英, 高金森.基于时变性聚团识别方法的高密度循环流化床内聚团分布特性[J]. 化学工业与工程, 2024,41(2): 77-85

SONG Dashan, LI Zhihui, SU Xin, WANG Chengxiu, LAN Xingying, GAO Jinsen.Characterization of cluster distribution in a high-density circulating fluidized bed based on a time-varying cluster identification threshold[J]. Chemcial Industry and Engineering, 2024,41(2): 77-85

[1] BI X, LIU X. High density and high solids flux CFB risers for steam gasification of solids fuels[J]. Fuel Processing Technology, 2010, 91(8): 915-920
[2] GRACE J R, ISSANGYA A S, BAI D, et al. Situating the high-density circulating fluidized bed[J]. AIChE Journal, 1999, 45(10): 2108-2116
[3] KIM S W, KIRBAS G, BI H, et al. Flow behavior and regime transition in a high-density circulating fluidized bed riser[J]. Chemical Engineering Science, 2004, 59(18): 3955-3963
[4] YAN Z, FAN Y, BI X, et al. Dynamic behaviors of feed jets and catalyst particles in FCC feed injection zone[J]. Chemical Engineering Science, 2018, 189: 380-393
[5] XIE D, BOWEN B D, GRACE J R, et al. Two-dimensional model of heat transfer in circulating fluidized beds. Part II: Heat transfer in a high density CFB and sensitivity analysis[J]. International Journal of Heat and Mass Transfer, 2003, 46(12): 2193-2205
[6] PÄRSSINEN J H, ZHU J. Axial and radial solids distribution in a long and high-flux CFB riser[J]. AIChE Journal, 2001, 47(10): 2197-2205
[7] YAN A, ZHU J. Scale-up effect of riser reactors: Particle velocity and flow development[J]. AIChE Journal, 2005, 51(11): 2956-2964
[8] SUN Z, ZHU J, ZHANG C. Numerical study on the hydrodynamics in high-density gas-solid circulating fluidized bed downer reactors[J]. Powder Technology, 2020, 370: 184-196
[9] WANG C, WANG G, LI C, et al. Catalytic ozone decomposition in a high density circulating fluidized bed riser[J]. Industrial & Engineering Chemistry Research, 2014, 53(16): 6613-6623
[10] WEI F, LU F, JIN Y, et al. Mass flux profiles in a high density circulating fluidized bed[J]. Powder Technology, 1997, 91(3): 189-195
[11] WEI F, WAN X, HU Y, et al. A pilot plant study and 2-D dispersion-reactor model for a high-density riser reactor[J]. Chemical Engineering Science, 2001, 56(2): 613-620
[12] LI Z Q, WU C, WEI F, et al. Experimental study of high-density gas-solids flow in a new coupled circulating fluidized bed[J]. Powder Technology, 2004, 139(3): 214-220
[13] SU X, WANG C, LAN X, et al. Axial flow structure of solids holdup in an 18 m high-density CFB riser based on pressure measurements[J]. Particuology, 2021, 54: 116-125
[14] SU X, WANG C, PEI H, et al. Experimental study of solids motion in an 18 m gas-solids circulating fluidized bed with high solids flux[J]. Industrial & Engineering Chemistry Research, 2019, 58(51): 23468-23480
[15] CHEN J. Experiments that address phenomenological issues of fast fluidization[J]. Chemical Engineering Science, 1999, 54(22): 5529-5539
[16] SEO M W, SUH Y H, KIM S D, et al. Cluster and bed-to-wall heat transfer characteristics in a dual circulating fluidized bed[J]. Industrial & Engineering Chemistry Research, 2012, 51(4): 2048-2061
[17] MCMILLAN J, SHAFFER F, GOPALAN B, et al. Particle cluster dynamics during fluidization[J]. Chemical Engineering Science, 2013, 100: 39-51
[18] GÓMEZ N, MOLINA A, MARIN G B, et al. From 3D to 1D: Capturing the effect of particle clusters in Downers in the fluid catalytic cracking of gasoil[J]. Chemical Engineering Research and Design, 2021, 170: 366-379
[19] CARLOS VARAS Á E, PETERS E A J F, KUIPERS J A M. Computational fluid dynamics-discrete element method (CFD-DEM) study of mass-transfer mechanisms in riser flow[J]. Industrial & Engineering Chemistry Research, 2017, 56(19): 5558-5572
[20] WANG C, LI C, LAN X, et al. Particle clustering (mesoscale structure) of high-flux gas-solid circulating fluidized bed[J]. Particuology, 2020, 48: 144-159
[21] MANYELE S V, PÄRSSINEN J H, ZHU J. Characterizing particle aggregates in a high-density and high-flux CFB riser[J]. Chemical Engineering Journal, 2002, 88(1/2/3): 151-161
[22] WEI X, ZHU J. A comprehensive characterization of aggregative flow in a circulating fluidized bed (1): High-density riser[J]. Industrial & Engineering Chemistry Research, 2020, 59(22): 10315-10327
[23] YIN S, ZHONG W, SONG T, et al. Clusters identification and meso-scale structures in a circulating fluidized bed based on image processing[J]. Advanced Powder Technology, 2019, 30(12): 3010-3020
[24] 曾鑫, 阳绍军, 王圣典, 等. 密相输运床的团聚物频率和持续时间[J]. 化工学报, 2013, 64(5):1614-1620 ZENG Xin, YANG Shaojun, WANG Shengdian, et al. Cluster frequency and existence time in dense transport bed[J]. CIESC Journal, 2013, 64(5): 1614-1620(in Chinese)
[25] WU G, YANG X, HE Y. Experimental exploration of particle cluster characteristics in the gas-solid diameter-varying fluidized bed[J]. Powder Technology, 2023, 429: 118948
[26] ZHANG H, JOHNSTON P M, ZHU J, et al. A novel calibration procedure for a fiber optic solids concentration probe[J]. Powder Technology, 1998, 100(2/3): 260-272
[27] DENG B, ZHANG Y, ZHANG M, et al. Identification and dynamic properties of clusters for Geldart group B particles in a circulating fluidized bed[J]. Chemical Engineering Science, 2022, 248: 117265
[28] SHARMA A K, TUZLA K, MATSEN J, et al. Parametric effects of particle size and gas velocity on cluster characteristics in fast fluidized beds[J]. Powder Technology, 2000, 111(1/2): 114-122
[29] LIU Y, DAI Q, QI H. Cluster identification criterion with experimental validation for the cluster solid holdup model during fluidization[J]. Powder Technology, 2020, 373: 459-467
[30] WANG C, LUO M, SU X, et al. A sliding-window based signal processing method for characterizing particle clusters in gas-solids high-density CFB reactor[J]. Chemical Engineering Journal, 2023, 452: 139141
[31] XU J, ZHU J. A new method for the determination of cluster velocity and size in a circulating fluidized bed[J]. Industrial & Engineering Chemistry Research, 2012, 51(4): 2143-2151