奈米銅粉 / 二氧化矽複合材之熱、質傳研究

The heat and mass transfer studies on the copper nanopowder / silica gel composite material

吳家欣(Chia-Hsin Wu)

指導教授 ： 鍾財王

中原大學/工學院/化學工程研究所/碩士(2005年)

https://doi.org/10.6840/cycu200500212

摘要

本研究係以溶膠-凝膠法（Sol-Gel process）製備二氧化矽多孔吸附材過程中，利用奈米銅粉作為添加劑用以提升此複合吸附材本身之熱傳導係數，用以降低吸附式製冷設備中熱交換器內部熱傳阻力為目的。並針對添加劑添加量與黏結劑濃度為參數分別對熱傳導係數與對水氣吸附質傳阻力大小為研究項目。

由結果顯示矽膠結構會受到有無添加奈米銅粉的影響，其中矽膠整體之比表面積、孔體積與平均孔徑皆隨添加量的增加而增加，且約在添加0.2公克銅粉後變化量則趨於穩定。因添加銅粉對矽膠結構的影響，在經研磨過後，未添加者其比表面積、孔體積隨粒徑愈小有先減後升的情況，而平均孔徑則隨粒徑愈小而上升；添加0.6公克銅粉者其比表面積、孔體積約維持不變，而平均孔徑也隨粒徑愈小上升。在銅粉的添加與黏結劑的使用對塊狀矽膠床的熱傳導係數則有提升的效果，且熱傳導係數隨兩者添加量與濃度的增加而增加，對水氣的質傳阻力大小則會受銅粉添加而加大，而在都有添加銅粉但添加量不同時，則以孔洞結構影響質傳阻力為主要因素。此外，對水氣的吸附量經由計算約與吸附劑的孔體積相等。

關鍵字

關鍵字：矽膠 ； 奈米銅粉 ； 複合吸附劑 ； 吸附式製冷 ； 熱傳導係數

並列摘要

In this study, the silica gel was prepared to be the porous adsorbent by using the sol-gel process. In order to reduce the heat transfer resistance of the heat exchanger in the adsorption cooling system, the copper nanopowder was added to the sorbent to improve the heat conductivity of the composite adsorbent. The heat and mass transfer resistance for water vapor were discussed by the amount of copper nanopowder and the concentration of the binder.

From the result, the structure of the silica gel was affected by adding the copper nanopowder. The specific surface area, pore volume, and average pore size increased with the amount of additive. When adding the copper nanopowder were 0.2g, the structure was insignificant change. Because of adding the copper nanopowder had the effect on the structure of silica gels. After grinding these adsorbent, the specific surface area and pore volume of the sorbent without copper nanopowder would be reduced first and then raised according to the reducing of the particle size. And the average pore size would be raised with the same condition. However, the specific surface area and pore volume of the sorbent adding 0.6g copper nanopowder would keep changeless with reducing the particle sizes. And the average pore size would be raised with the same condition.

The heat conductivity of the silica gels were improved by adding the copper nanopowder and increased with concentration of the binder. The mass transfer resistance was increased by adding the copper powder. But mass transfer resistance of the silica gels of the adding copper powder were affected mainly by the structure of the silica gel. It was not affected by the amount of adding additive. In addition, the uptakes for water vapor were similar to the amount of the pore volume in these adsorbents.

並列關鍵字

composite adsorbent ； adsorption cooling ； Key words：silica gel ； copper nanopowder ； heat conductivity

參考文獻

【2】Ferdi, S.; Kenneth S. W. S. and Jens, W. (2002) Handbook of Porous Solids Volume 3, Wiley-vch, pp.1547.

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Colloid and Surface Properties, and Biochemistry. John Wiley & Sons,

New York. pp.173.

【8】Tadahiro, M.; Shimio S.; Takashi O.; Tetushi W.; Tohru S. (1992) Control of pore size distribution of silica gel through sol-gel process using inorganic salts and surfactants as additives. Journal of Materials Science, 27, 1567~1574.