Permeability and thermal conductivity of compact chemical and physical adsorbents with expanded natural graphite as host matrix
Permeability and thermal conductivity of compact chemical and physical adsorbents with expanded natural graphite as host matrix
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DOI：
10.1016/j.ijheatmasstransfer.2012.04.016
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发表时间：
2012-07
影响因子：
5.2
通讯作者：
B. Tian;Z. Jin;Liwei Wang;Ruzhu Wang
中科院分区：
文献类型：
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作者：
B. Tian;Z. Jin;Liwei Wang;Ruzhu Wang
渗透性和导热性测试装置旨在研究紧凑型化学和物理吸附剂的传热和传质性能，即紧凑型 CaCl2 和使用膨胀天然石墨 (ENG) 作为主体基质的活性炭 (AC)。采用稳态热源法研究导热系数，并以氮气为气源测试渗透率。对于紧凑型 CaCl2 吸附剂，结果表明渗透率和导热率随 ENG 比例和紧凑型吸附剂的密度而变化。当致密样品的密度从400kg/m3变化到550kg/m3时，渗透率值为10-13∼10-11m2，并且随着ENG比例的减小而线性增加。当密度为550kg/m3、ENG比例为最小值16.7%时，导热系数值为1.08W/(m·K)，比粒状CaCl2提高了5倍。当ENG-AC比为1.5:1时，以ENG为基体的AC致密物理吸附剂的导热系数最高，为2.61W/(m·K)。类似地，热导率随着 ENG 比率的降低而下降。当ENG比例达到最小比例28.6%时，导热系数为2.08W/(m·K)，与颗粒AC的结果相比提高了5.8倍，相应的渗透率为5.16×10-11m2。 AC致密物理吸附剂的热导率和渗透率均优于CaCl2致密化学吸附剂的值。
Permeability and thermal conductivity test units were designed to study the heat and mass transfer performance of compact chemical and physical adsorbents, i.e. compact CaCl2and activated carbon (AC) using expanded natural graphite (ENG) as host matrix. The thermal conductivity was studied by steady-state heat source method and the permeability was tested with nitrogen as a gas source. For the compact CaCl2adsorbents, results show that permeability and thermal conductivity vary with the ratio of ENG and the density of compact adsorbents. The value of permeability is 10-13∼10-11m2when the density of compact sample change from 400kg/m3to 550kg/m3, and it keeps increasing linearly with the less ratio of ENG. The value of thermal conductivity is 1.08W/(m·K), which is increased by 5 times compared with granular CaCl2when the density is 550kg/m3and the ratio of ENG is the minimum value of 16.7%. The compact physical adsorbent of AC with ENG as matrix has the highest thermal conductivity of 2.61W/(m·K) when the ratio between ENG–AC is 1.5:1. Similarly, thermal conductivity drops down with the ratio of ENG decreasing. When the ratio of ENG reaches the minimum ratio of 28.6%, the thermal conductivity is 2.08W/(m·K), which is increased by 5.8 times if compared with the result of granular AC, and corresponding permeability is 5.16×10-11m2. The thermal conductivity and permeability of compact physical adsorbent of AC are all better than the values for the compact chemical adsorbent of CaCl2.