Effects of aeration on matrix temperature by infrared thermal imager and computational fluid dynamics during sludge bio-drying

WATER RESEARCH

卷:122

Article

Yu, Dawei^1,2  Yang, Min^1,2  Iq, Lu^1,2  Liu, Mengmeng^1,2  Wang, Yawei^1,2  Wei, Yuansong^1,2 

[1] Chinese Acad Sci, Res Ctr Ecoenvironm Sci, State Key Joint Lab Environm Simulat & Pollut Con, Beijing 100085, Peoples R China

[2] Univ Chinese Acad Sci, Beijing 100049, Peoples R China

关键词: Bio-drying;    Computational fluid dynamics;    Infrared thermal imager;    Aeration;    Matrix temperature;    Excess sludge;   

DOI  :  10.1016/j.watres.2017.06.003

来源: Elsevier

【 摘 要 】

The effect of aeration on the pile matrix temperature was investigated using thermocouples and Infrared Thermal Imager (IRI) for temperature sensing, and Computational Fluid Dynamics (CFD) for modelling of temperature variation during aeration in a full-scale sludge biodrying plant. With aeration saving of 20%, the improved strategy speeded up biodrying from 21 days to 14 days, while achieving similar drying effect. A persistent thermocouple recorded the one-dimensional (1D) total temperature variation of all aeration strategies. The IRI captured the rapid two-dimensional (2D) pile temperature dropped from 72.5 degrees C to 30.3 degrees C during 6 min of aeration, which mechanism suggested as the latent heat of moisture evaporation and sensible heat of air exchange. The CFD three-dimensional (3D) CFD results highlight the importance of latent heat rather than sensible heat. Therefore, the pile temperature drop inferred is Delta T = 5.38 degrees C theoretically and Delta T = 5.17 +/- 4.56 degrees C practically, per unit of MC removed. These findings also emphasize the possibility of a pile temperature valley, due to excessive aeration under unsaturated vapour conditions. Surface temperature monitored by IRI coupled with 3D temperature simulated by CFD rapidly gives a clear matrix temperature evolution, empowering biodrying by more accurate temperature and aeration. (C) 2017 Elsevier Ltd. All rights reserved.

【 授权许可】

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