Deposition Characteristics of Gasified Fine Ash Particles in the Mixer
-
摘要: 混合器是煤气化合成气分级初步净化工艺中的关键设备之一，合成气中细灰颗粒在其内的沉积行为显著影响气化系统的长周期稳定运行。采用颗粒沉积临界速度模型对气化细灰颗粒在混合器中的沉积特性进行了数值模拟，研究了不同颗粒粒径、气体流速及混合器结构对颗粒沉积特性的影响规律。结果表明，相同入口气速下，气化细灰在混合器内壁面的沉积率随颗粒粒径的增大总体呈下降趋势，尤其是粒径5~13 μm的颗粒；粒径1 μm的颗粒在Wall4壁面的单位面积沉积量最大；不同粒径颗粒的沉积率随气体流速的变化不同，但总体呈现下降的趋势；水管出口端面到渐缩套管口端面距离H的改变对颗粒在混合器内的沉积率无明显影响；混合器C是一种可有效避免缩口面附近发生堵塞的结构。Abstract: The mixer is an important part of the purification system of multi-nozzle opposed gasification technology, however, the adhesion of fly ash particles on the wall of the mixer can cause clogging, resulting in lower syngas purification efficiency and even affecting the gasification efficiency of the gasifier and leading to economic losses. In this paper, the deposition characteristics of gasification fine ash particles in the mixer are numerically simulated by using the particle deposition critical velocity model, and the influence of different particle sizes, gas flow rate and mixer structure on particle deposition is investigated. The results show that, at the same inlet gas velocity, the deposition rate of gasified fine ash on the inner wall surface of the mixer generally tends to decrease with the increase of particle size, especially for 5-13 μm particles; the deposition of 1 μm particles on the surface of wall4 is the largest per unit area; the deposition rate of different particle sizes varies with the gas flow rate, but generally shows a decreasing trend; the change of the distance H from the outlet face of the water pipe to the end face of the indented casing mouth has no significant effect on the deposition rate of particles in the mixer; mixer C is a structure that can effectively avoid clogging near the indented face.
-
图 4 本文模拟结果与文献[21]结果比较
Figure 4. Comparision of simulation results in this paper with those in literature [21]
图 5 不同粒径颗粒在壁面的沉积率
Figure 5. Deposition rate of particles with different particle sizes on the wall
图 6 不同粒径颗粒在壁面的碰撞率
Figure 6. Collision rate of particles with different particle sizes on the wall
图 7 不同粒径颗粒的临界沉积速度和临界壁面剪切速度
Figure 7. Critical deposition velocity and critical wall shear velocity of particles of different particle sizes
图 8 入口气速为10 m/s时颗粒在混合器内各壁面的单位面积沉积量
Figure 8. Deposition of particles per unit area on each wall in the mixer at an inlet gas velocity of 10 m/s
图 9 入口气速为10 m/s时不同粒径颗粒在混合器内的运动轨迹
Figure 9. Trajectory of particles with different particle sizes in the mixer at an inlet gas velocity of 10 m/s
图 10 不同入口气速时颗粒的沉积率
Figure 10. Deposition rate of particles at different inlet gas velocities
图 11 不同入口气速下10 μm颗粒在混合器各壁面的单位面积沉积量
Figure 11. Deposition of 10 μm particles per unit area on each wall of the mixer at different inlet gas velocities
图 12 10 μm颗粒在不同入口气速下的运动轨迹
Figure 12. Trajectory of 10 μm particles at different inlet gas velocities
图 13 1~50 μm颗粒在不同结构混合器内各壁面的单位面积沉积量
Figure 13. Deposition of 1~50 μm particles per unit area at each wall in different structured mixers
表 1 不同混合器的关键结构参数
Table 1. Structural key parameters of different mixers
Mixer H/mm α/(°) A 130 30 B 65 30 C 0 15 D 0 30 E 0 45 
下载: 导出CSV
表 2 不同结构混合器的细灰沉积率
Table 2. Deposition rate of fine ash for different structure mixers
Mixer Pd/% A 13.82 B 15.16 C 14.37 D 14.01 E 17.92
下载: 导出CSV
-
[1] 王辅臣. 煤气化技术在中国: 回顾与展望[J]. 洁净煤技术, 2021, 27(1): 1-33. [2] 陈雪莉. 气流床煤气化系统中初步净化过程研究[D]. 上海: 华东理工大学, 2004. [3] 王辅臣, 代正华. 煤气化-煤炭高效清洁利用的核心技术[J]. 化学世界, 2015, 56(1): 51-55. [4] 赵建会. 多喷嘴对置式水煤浆气化装置运行问题分析和优化[J]. 氮肥与合成气, 2019, 47(10): 25-28. [5] BRACH R M, DUNN P F. A mathematical model of the impact and adhesion of microsphers[J]. Aerosol Science and Technology, 1992, 16(1): 51-64. doi: 10.1080/02786829208959537 [6] EL-BATSH H, HASELBACHER H. Numerical Investigation of the Effect of Ash Particle Deposition on the Flow Field Through Turbine Cascades[M]. Amsterdam: International Gas Turbine Institude, 2002. [7] LI J, DU W, CHENG L. Numerical simulation and experiment of gas-solid two phase flow and ash deposition on a novel heat transfer surface[J]. Applied Thermal Engineering, 2017, 113: 1033-1046. doi: 10.1016/j.applthermaleng.2016.10.198 [8] 袁宝强, 赵哲华, 王湛, 等. 基于动网格的飞灰沉积特性数值模拟[J]. 工程热物理学报, 2019, 40(6): 1332-1337. [9] 周君辉, 张靖周. 涡轮叶栅内粒子沉积特性的数值研究[J]. 航空学报, 2013, 34(11): 2492-2499. [10] XU W, ZHU K, WANG J, et al. Modeling and numerical analysis of the effect of blade roughness on particle deposition in a flue gas turbine[J]. Powder Technology, 2019, 347: 59-65. doi: 10.1016/j.powtec.2019.02.033 [11] ZHANG P, XU C, KUANG J, et al. Investigation on the ash deposition of a radiant syngas cooler using critical velocity model[J]. Energy Reports, 2020, 6: 112-126. doi: 10.1016/j.egyr.2020.04.015 [12] 杨玉辉. 合成气管线积灰原因分析及解决方案[J]. 大氮肥, 2021, 44(1): 36-39. doi: 10.3969/j.issn.1002-5782.2021.01.011 [13] 王德胜, 丁盼盼. 水煤气带灰的原因及改造措施[J]. 上海化工, 2016, 41(10): 42-44. doi: 10.3969/j.issn.1004-017X.2016.10.017 [14] 田秀山. 气-液同轴射流的LES-VOF模拟[J]. 燃烧科学与技术, 2012, 18(5): 461-466. [15] TIAN L, AHMADI G. Particle deposition in turbulent duct flows: Comparisons of different model predictions[J]. Journal of Aerosol Science, 2007, 38(4): 377-397. doi: 10.1016/j.jaerosci.2006.12.003 [16] ZHANG Z, CHEN Q. Comparison of the Eulerian and Lagrangian methods for predicting particle transport in enclosed spaces[J]. Atmospheric Environment, 2007, 41(25): 5236-5248. doi: 10.1016/j.atmosenv.2006.05.086 [17] 刘赛赛. 小尺度颗粒在液固两相流体中的迁移特性研究[D]. 山东青岛: 中国海洋大学, 2015. [18] JOHNSON K L, KENDALL K, ROBERTS A D. Surface energy and the contact of elastic solids[J]. Proceedings of the Royal Society of London, Series A: Mathematical and Physical Sciences, 1971, 324(1558): 301-313. [19] 穆林, 赵亮, 尹洪超. 废液焚烧余热锅炉内气固两相流动与飞灰沉积的数值模拟[J]. 中国电机工程学报, 2012, 32(29): 30-37, 15. [20] WALSH P M, SAYRE A N, LOEHDEN D O, et al. Deposition of bituminous coal ash on an isolated heat exchanger tube: Effects of coal properties on deposit growth[J]. Progress in Energy and Combustion Science, 1990, 16(4): 327-345. doi: 10.1016/0360-1285(90)90042-2 [21] KVASNAK W, AHMADI G, BAYER R, et al. Experimental investigation of dust particle deposition in a turbulent channel flow[J]. Journal of Aerosol Science, 1993, 24(6): 795-815. doi: 10.1016/0021-8502(93)90047-D [22] 李金波. 多组分复杂介质余热锅炉传热与动态特性研究[D]. 济南: 山东大学, 2017. -
点击查看大图
计量
- 文章访问数: 69
- HTML全文浏览量: 55
- PDF下载量: 4
- 被引次数: 0
