Adsorption kinetics analysis of water on silica gel in two configurations of tubular reactors.

Tubular adsorption reactors have been used in solar cooling systems since 1983. The original design consisted in a metal screen tube concentrically inserted into a copper tube; granules of solid adsorbent are packed in the space between the two tubes. Two experimental setups were used to measure the degree of contribution provided by radial adsorbate flow through the metal screen on adsorption kinetics: the first setup was composed by a tube fully filled with adsorbent, resulting in mainly axial adsorbate flow, while the second one was composed by an external tube with an internal, coaxial metal mesh tube leading to free adsorbent flow lengthwise, resulting in predominant radial flow through the adsorbent bed. The adsorption working pair was constituted by silica gel and water. This particular pair is preferred for adsorption chillers due to its superior thermodynamic characteristics. Temperature and mass measurements were made along the adsorption process to compare the heat and mass transfers obtained with each reactor configuration.

自1983年起，管式吸附反应器（tubular adsorption reactors）便已应用于太阳能制冷系统。其初始设计为将金属筛网管同心嵌套于铜管内部，固体吸附剂颗粒填充于两管之间的环形间隙中。本研究搭建两套实验装置，旨在量化吸附质穿过多孔金属筛层的径向流动对吸附动力学（adsorption kinetics）的贡献程度：第一套装置为完全填充吸附剂的单管式结构，吸附质流动以轴向为主；第二套装置由外管与内置同轴金属网筒组成，吸附质可沿轴向自由流通，使得吸附剂床层（adsorbent bed）内的流动以径向为主。本次实验选用的吸附工质对（adsorption working pair）为硅胶与水。该工质对凭借优异的热力学特性，成为吸附式制冷机（adsorption chillers）的主流选型。实验过程中对吸附全过程的温度与质量参数进行了同步采集，以对比两种反应器构型下的传热与传质性能。