ABSTRACT A series of experimental investigations had been performed to analyze the heat and mass transfer performance for two novel types of silica-based consolidated composite adsorbents developed by the freeze-drying method. The first type of adsorbent is silica gel consolidated with carboxymethyl cellulose (CMC) (SC), while the other is silica gel consolidated with CMC and carbon fiber powder (SCC). Results indicate that the thermal conductivity of consolidated composite adsorbents increases with the mass proportion of carbon fiber powder, while it decreases with the increasing moisture content in the preparation process of the adsorbents. When the mass ratio of silica gel, CMC, and carbon fiber powder is 4:1:4, the highest thermal conductivity of consolidated composite adsorbent obtained from experiments reaches 1.66 W m−1 K−1, which is 13.4 times greater than that of pure silica gel. Furthermore, the results of macroporous properties analysis of typical samples including SC20 and SCC20 (where the 20 means that the undried samples have a water content of 20% by mass during the preparation process) show that heat transfer additives effectively improve the macroporous porosity and permeability of the consolidated composite adsorbents. The study on adsorption dynamic performance indicates that the freeze-drying method helps to improve the adsorption performance including adsorption rate and equilibrium water uptake. The experimental results also show that the mass transfer coefficient K of the two typical samples are approximately stable at 5 × 10−3 s−1 when the adsorption temperature is ranged between 30 and 40°C, which are almost twice the corresponding values of the samples developed by heating–drying method. Therefore, the proposed approach which is the consolidation with heat transfer additives combined with freeze-drying method is effective for simultaneously enhancing the heat and mass transfer performance of the silica gel adsorbents.

中文翻译：

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冻干法制备的易合成硅胶/碳纤维基固结复合吸附剂的传热传质性能

摘要 已经进行了一系列实验研究，以分析通过冷冻干燥方法开发的两种新型二氧化硅基固结复合吸附剂的传热和传质性能。第一种吸附剂是用羧甲基纤维素（CMC）（SC）固结的硅胶，而另一种是用CMC和碳纤维粉（SCC）固结的硅胶。结果表明，固结复合吸附剂的导热系数随着碳纤维粉体质量比例的增加而增加，而在吸附剂制备过程中随着水分含量的增加而降低。当硅胶、CMC和碳纤维粉的质量比为4:1:4时，实验得到的固结复合吸附剂的最高导热系数达到1.66 W m-1 K-1，即13。比纯硅胶大4倍。此外，包括SC20和SCC20在内的典型样品的大孔性能分析结果（其中20表示未干燥样品在制备过程中的含水量为20质量％）表明，传热添加剂有效地提高了大孔孔隙率和渗透率固结复合吸附剂。吸附动力学性能研究表明，冷冻干燥法有助于提高吸附性能，包括吸附速率和平衡吸水量。实验结果还表明，当吸附温度在 30 到 40°C 之间时，两个典型样品的传质系数 K 近似稳定在 5 × 10-3 s-1，这几乎是通过加热干燥方法开发的样品相应值的两倍。因此，所提出的将传热添加剂结合冷冻干燥法的方法对于同时提高硅胶吸附剂的传热传质性能是有效的。