污泥厚度对超声波辅助热风干燥污泥特性的影响

doi:10.11949/0438-1157.20200605

摘要/Abstract

摘要：

由于在超声波声场中污泥微粒会发生分层现象，声互作用力使得微粒于超声传播方向相垂直的平面上发生凝聚，因此污泥厚度大小对超声波辅助热风干燥污泥特性有着重要的影响。通过实验的方法，对不同厚度污泥在超声波声场中的分层凝聚现象进行观察，发现污泥内部结构的分层现象随其厚度的增加而明显。研究了超声波对不同厚度污泥干燥过程中各时期干燥时长、干燥速率的影响效果，以及分析了湿分有效扩散系数（D_eff）随污泥厚度变化的情况。从实验结果中可以发现，在超声波功率小于135 W范围内，污泥厚度越大，干燥过程中第一降速期时间越长，干燥速率提升效果越差，而对恒速干燥期内干燥速率提升效果更明显；在5、10以及15 mm厚度的污泥中，10 mm厚度的污泥在超声波功率小于90 W的条件下总干燥时长降低幅度最大，干燥速率在各阶段提速也较快；污泥厚度越小，超声波功率对污泥湿分有效扩散系数影响越小，反之影响越大。

关键词: 污泥, 超声波, 干燥, 显微结构, 聚集

Abstract:

Due to the stratification of sludge particles in the ultrasonic field, the acoustic interaction forces the particles to agglomerate on a plane perpendicular to the direction of ultrasonic propagation. Therefore, the thickness of sludge can significantly influence the characteristics of ultrasound-assisted hot air convective drying municipal sewage sludge. In this paper, the stratified aggregation phenomenon of sludge with different thicknesses was observed in the ultrasonic field using the experimental method. It was found that the stratification of the internal structure of sludge became more obvious with the increase of its thickness. The effects of ultrasound on the drying time and the drying rate of sludge with various thicknesses were studied. Meanwhile, the effective moisture diffusivity (D_eff) was analyzed. The experimental results demonstrated that the larger the sludge thickness, the longer the time length of the first falling rate stage and the promotion of the drying rate was worse when the ultrasonic power was less than 135 W. The situation was opposite at the constant rate stage. Among the sludge with the thicknesses of 5, 10, and 15 mm, the total drying time and energy consumption of the sludge with a thickness of 10 mm decreased the most substantially under the condition of ultrasonic power less than 90 W. The smaller the thickness of sludge is, the less obvious the effect of ultrasound on the effective moisture diffusivity, and vice versa.

Key words: sludge, ultrasound, drying, microstructure, aggregation

中图分类号:

TK 121

牟新竹, 陈振乾. 污泥厚度对超声波辅助热风干燥污泥特性的影响[J]. 化工学报, 2020, 71(S2): 241-252.

Xinzhu MOU, Zhenqian CHEN. Effect of sludge thickness on characteristics of ultrasonic assisted hot air drying sludge[J]. CIESC Journal, 2020, 71(S2): 241-252.

图/表 14

图1 超声波辅助热风干燥污泥实验装置

Fig.1 Schematic diagram of ultrasound-assisted hot air drying sludge setup

图2 污泥冻干处理及显微观察装置

Fig.2 Schematic diagram of sludge freeze-drying treatment and microscopic observation device

图3 污泥图像处理前后效果对比

Fig.3 Comparison of effects before and after image processing

图4 利用ArcGIS构建的污泥三维图像

Fig.4 3D scene of sludge constructed using ArcGIS

图5 污泥三维图像

Fig.5 3D scenes of sludge

表1 不同厚度污泥经超声波（功率为90 W）预处理后的孔隙率值

Table 1 Porosity of sludge with different thicknesses pretreated by ultrasound (90 W)

污泥厚度/mm	孔隙率/%	提升比/%
5	52.3	0.97
10	53.6	3.47
15	54.2	4.63

图6 不同超声波功率下含湿率变化和干燥速率分布

Fig.6 Evolutions of moisture ratio and drying rate profiles at different ultrasonic power

图7 不同超声波功率下干燥各时期时长比较

Fig.7 Comparison of duration of each stage of drying under different ultrasonic power

图8 不同厚度污泥干燥时长降低幅度

Fig.8 Percentage of time length reduction of sludge with 3 kinds of thicknesses

图9 不同超声波功率下各时期干燥速率

Fig.9 Drying rate of each stage under different ultrasonic power

图10 不同厚度污泥干燥速率提升幅度

Fig.10 Percentage of increasing drying rate of sludge with 3 kinds of thicknesses

表2 超声辅助对流干燥污泥的方差分析

Table 2 Analysis of variance for sample in ultrasound-assisted convective drying

时期	来源	平方和（SS）	自由度（D_f）	MS均方	F检验
恒速期	污泥厚度	2.002×10^-8	2	1.001×10^-8	2741.760
	超声波功率	4.395×10^-10	2	2.198×10^-10	60.194
	误差	1.460×10^-11	4	3.651×10^-12
	总和	2.048×10^-8	8	4.762×10^-9
第一降速期	污泥厚度	9.524×10^-9	2	2.771×10^-10	135.052
	超声波功率	5.543×10^-10	2	3.526×10^-11	7.860
	误差	1.140×10^-10	4
	总和	1.022×10^-8	8
第二降速期	污泥厚度	1.514×10^-9	2	7.569×10^-10	25.512
	超声波功率	3.868×10^-11	2	1.934×10^-11	0.652
	误差	1.187×10^-10	4	2.967×10^-11
	总和	1.071×10^-9	8

图11 lnMR与t拟合关系图（污泥厚度15 mm，超声波功率45 W）

Fig.11 Linear fitting between lnMR vst (thickness of sludge: 15 mm, ultrasonic power: 45 W)

图12 不同功率超声波下污泥湿分有效扩散系数（Deff）

Fig.12 Effective moisture diffusivity (Deff) of sludge under different ultrasonic power

参考文献 36

1	王兴栋, 张斌, 余广炜, 等. 不同粒径污泥热解制备生物炭及其特性分析[J]. 化工学报, 2016, 67(11): 4808-4816.
	Wang X D, Zhang B, Yu G W, et al. Preparation of biochar with different particle sized sewage sludge and its characteristics [J]. CIESC Journal, 2016, 67(11): 4808-4816.
2	Li R J, Wen W B, Lin J Y. Enhanced dewaterability of textile dyeing sludge using micro-electrolysis pretreatment [J]. Journal of Environmental Management, 2015, 161: 181-187.
3	Gayathri T, Kavitha S, Kumar S A, et al. Effect of citric acid induced deflocculation on the ultrasonic pretreatment efficiency of dairy waste activated sludge [J]. Ultrasonics Sonochemistry, 2015, 22: 333-340.
4	宋艳培, 庄修政, 詹昊, 等. 污泥与褐煤共水热碳化的协同特性研究[J]. 化工学报, 2020, 71(5): 2320-2330.
	Song Y P, Zhuang X Z, Zhan H, et al. Investigation on thermochemical conversion characteristics and regularity of co-hydrothermal carbonization solid fuel from sewage sludge and lignite [J]. CIESC Journal, 2020, 71(5): 2320-2330.
5	李海燕, 刘欢, 汪家兴, 等. 基于化学改性的脱水污泥低温热风干化特性[J]. 化工学报, 2018, 69(7): 3257-3262.
	Li H Y, Liu H, Wang J X, et al. Characteristics of dehydrated sludge based on chemical modification: low temperature hot-air drying [J]. CIESC Journal, 2018, 69(7): 3257-3262.
6	李亚林, 刘蕾, 张毅, 等. 电渗透/Fe-过硫酸盐氧化协同强化污泥深度脱水[J]. 化工学报, 2016, 67(9): 4013-4019.
	Li Y L, Liu L, Zhang Y, et al. Coordination of electro-osmotic and Fe-persulfate oxidation process on sewage sludge deep-dewatering [J]. CIESC Journal, 2016, 67(9): 4013-4019.
7	Zhan T L, Zhan X, Lin W, et al. Field and laboratory investigation on geotechnical properties of sewage sludge disposed in a pit at Changan landfill, Chengdu, China [J]. Engineering Geology, 2014, 170: 24-32.
8	Cieślik B M, Namiesnik J, Konieczka P. Review of sewage sludge management: standards, regulations and analytical methods [J]. Journal of Cleaner Production, 2015, 90: 1-15.
9	Tuncal T, Uslu O. A review of dehydration of various industrial sludges [J]. Drying Technology, 2014, 32(14): 1642-1654.
10	Siucińska K, Konopacka D. Application of ultrasound to modify and improve dried fruit and vegetable tissue: a review [J]. Drying Technology, 2014, 32(11): 1360-1368.
11	Bantle M, Hanssler J. Ultrasonic convective drying kinetics of clipfish during the initial drying period [J]. Drying Technology, 2013, 31(11): 1307-1316.
12	Sabarez H T, Gallego-Juarez J A, Riera E. Ultrasonic-assisted convective drying of apple slices [J]. Drying Technology, 2012, 30(9): 989-997.
13	García-Pérez J V, Cárcel J A, Benedito J, et al. Power ultrasound mass transfer enhancement in food drying [J]. Food and Bioproducts Processing, 2007, 85(3): 247-254.
14	Packyam G S, Kavitha S, Kumar S A, et al. Effect of sonically induced deflocculation on the efficiency of ozone mediated partial sludge disintegration for improved production of biogas [J]. Ultrasonics Sonochemistry, 2015, 26: 241-248.
15	Bantle M, Eikevik T M. A study of the energy efficiency of convective drying systems assisted by ultrasound in the production of clipfish [J]. Journal of Cleaner Production, 2014, 65: 217-223.
16	Lima A G B D, Neto S R F, Silva W P. Heat and Mass Transfer in Porous Media [M]. Berlin Heidelberg: Springer, 2012: 161-185.
17	Toğru I T, Pehlivan D. Modelling of thin layer drying kinetics of some fruits under open-air sun drying process [J]. Journal of Food Engineering, 2004, 65(3): 413-425.
18	Shi Q L, Zheng Y Q, Zhao Y. Mathematical modeling on thin-layer heat pump drying of yacon (Smallanthus sonchifolius) slices [J]. Energy Conversion and Management, 2013, 71: 208-216.
19	Koua K B, Fassinou W F, Gbaha P, et al. Mathematical modelling of the thin layer solar drying of banana, mango and cassava [J]. Energy, 2009, 34(10): 1594-1602.
20	Shen F, Peng L, Zhang Y Z, et al. Thin-layer drying kinetics and quality changes of sweet sorghum stalk for ethanol production as affected by drying temperature [J]. Industrial Crops and Products, 2011, 34(3): 1588-1594.
21	Doymaz I. Thin-layer drying behaviour of mint leaves [J]. Journal of Food Engineering, 2006, 74(3): 370-375.
22	Sun L X, Liu S X, Wang J X, et al. The effects of grain texture and phenotypic traits on the thin-layer drying rate in maize (Zea mays L.) inbred lines [J]. Journal of Integrative Agriculture, 2016, 15(2): 317-325.
23	Fu B A, Chen M Q. Thin-layer drying kinetics of lignite during hot air forced convection [J]. Chemical Engineering Research and Design, 2015, 102: 416-428.
24	Pillai G M. Thin layer drying kinetics, characteristics and modeling of plaster of Paris [J]. Chemical Engineering Research and Design, 2013, 91(6): 1018-1027.
25	Huang Y W, Chen M Q, Jia L. Assessment on thermal behavior of municipal sewage sludge thin-layer during hot air forced convective drying [J]. Applied Thermal Engineering, 2016, 96: 209-216.
26	Sun G Y, Chen M Q, Huang Y W. Evaluation on the air-borne ultrasound-assisted hot air convection thin-layer drying performance of municipal sewage sludge [J]. Ultrasonics Sonochemistry, 2017, 34: 588-599.
27	赵芳, 陈振乾, 施明恒. 超声波作用下污泥水分扩散过程的数值模拟[J]. 工程热物理学报, 2011, 32(4): 659-662.
	Zhao F, Chen Z Q, Shi M H. Numerical simulation on moisture diffusion process of sludge under the effect of ultrasound [J]. Journal of Engineering Thermophysics, 2011, 32(4): 659-662.
28	Trujillo F J, Juliano P, Gustavo B C, et al. Separation of suspensions and emulsions via ultrasonic standing waves - a review [J]. Ultrasonics Sonochemistry, 2014, 21(6): 2151-2164.
29	王宝军, 施斌, 蔡奕, 等. 基于GIS的黏性土SEM图像三维可视化与孔隙度计算[J]. 岩土力学, 2008, (1): 251-255.
	Wang B J, Shi B, Cai Y, et al. 3D visualization and porosity computation of clay soil SEM image by GIS [J]. Rock and Soil Mechanics, 2008, (1): 251-255.
30	Zhang X Y, Chen M Q, Huang Y W, et al. Isothermal hot air drying behavior of municipal sewage sludge briquettes coupled with lignite additive [J]. Fuel, 2016, 171: 108-115.
31	Chung L L, Tasirin S M, Wan R W D. A new variable diffusion drying model for the second falling rate period of paddy dried in a rapid bin dryer [J]. Drying Technology, 2003, 21(9): 1699-1718.
32	Belhamri A. Characterization of the first falling rate period during drying of a porous material [J]. Drying Technology, 2003, 21(7): 1235-1252.
33	Mowla D, Tran H N, Allen D G. A review of the properties of biosludge and its relevance to enhanced dewatering processes [J]. Biomass and Bioenergy, 2013, 58: 365-378.
34	Choudhury D, Sahu J K, Sharma G D. Moisture sorption isotherms, heat of sorption and properties of sorbed water of raw bamboo (Dendrocalamus longispathus) shoots [J]. Industrial Crops and Products, 2011, 33(1): 211-216.
35	Lasagabaster A, Abad M J, Barral L, et al. FTIR study on the nature of water sorbed in polypropylene (PP)/ethylene alcohol vinyl (EVOH) films [J]. European Polymer Journal, 2006, 42(11): 3121-3132.
36	Yao Y. Enhancement of mass transfer by ultrasound: application to adsorbent regeneration and food drying/dehydration [J]. Ultrasonics Sonochemistry, 2016, 31: 512-531.

[1]	吴馨, 龚建英, 靳龙, 王宇涛, 黄睿宁. 超声波激励下铝板表面液滴群输运特性的研究[J]. 化工学报, 2023, 74(S1): 104-112.
[2]	赵亚欣, 张雪芹, 王荣柱, 孙国, 姚善泾, 林东强. 流穿模式离子交换层析去除单抗聚集体[J]. 化工学报, 2023, 74(9): 3879-3887.
[3]	刘春雨, 周桓宇, 马跃, 岳长涛. CaO调质含油污泥干燥特性及数学模型[J]. 化工学报, 2023, 74(7): 3018-3027.
[4]	屈园浩, 邓文义, 谢晓丹, 苏亚欣. 活性炭/石墨辅助污泥电渗脱水研究[J]. 化工学报, 2023, 74(7): 3038-3050.
[5]	王光宇, 张锴, 张凯华, 张东柯. 微波加热干燥煤泥热质传递及其能耗特性分析[J]. 化工学报, 2023, 74(6): 2382-2390.
[6]	王新悦, 王俊杰, 曹思贤, 王翠, 李灵坤, 吴宏宇, 韩静, 吴昊. 玻璃内包材界面修饰对机械应力诱导的单克隆抗体聚集体形成的影响[J]. 化工学报, 2023, 74(6): 2580-2588.
[7]	张兰河, 赖青燚, 王铁铮, 关潇卓, 张明爽, 程欣, 徐小惠, 贾艳萍. H₂O₂对SBR脱氮效率和污泥性能的影响[J]. 化工学报, 2023, 74(5): 2186-2196.
[8]	侯文起, 孙彦, 董晓燕. 碱化修饰甲状腺素运载蛋白显著增强对淀粉样β蛋白聚集的抑制作用[J]. 化工学报, 2023, 74(5): 2100-2110.
[9]	陈宇豪, 陈晓平, 马吉亮, 梁财. 市政污泥回转窑焚烧气态污染物排放特性研究[J]. 化工学报, 2023, 74(5): 2170-2178.
[10]	王倩倩, 刘明言, 马永丽. 水中超声波脱气的效应研究[J]. 化工学报, 2023, 74(4): 1693-1702.
[11]	陈毓明, 历伟, 严翔, 王靖岱, 阳永荣. 初生态聚乙烯聚集态结构调控研究进展[J]. 化工学报, 2023, 74(2): 487-499.
[12]	郭祥, 乔金硕, 王振华, 孙旺, 孙克宁. 碳燃料固体氧化物燃料电池结构研究进展[J]. 化工学报, 2023, 74(1): 290-302.
[13]	罗欣宜, 冯超, 刘晶, 乔瑜. 污泥不同热处理工艺产物磷的浸出回收实验研究[J]. 化工学报, 2022, 73(9): 4034-4044.
[14]	沈嘉辉, 王侃宏, 郁达伟, 胡大洲, 魏源送. 游离氨调理污泥厌氧消化优化产甲烷过程与强化有机物释放[J]. 化工学报, 2022, 73(9): 4147-4155.
[15]	张军, 胡升, 顾菁, 袁浩然, 陈勇. 甲醇体系电镀污泥衍生磁性多金属材料催化糠醛加氢转化[J]. 化工学报, 2022, 73(7): 2996-3006.