Modeling of the limiting step of water sorption by composite sorbents of the “calcium chloride in porous matrix” type
Modeling of the limiting step of water sorption by composite sorbents of the “calcium chloride in porous matrix” type
复制标题
“多孔基质中的氯化钙”型复合吸附剂的水吸附限制步骤的建模
DOI：
10.1134/s0040579507010095
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发表时间：
2007
影响因子：
0.8
通讯作者：
Yuri I. Aristov
中科院分区：
文献类型：
--
作者：
N. Ostrovskii;N. Chumakova;N. M. Bukhavtsova;N. Vernikovskaya;Yuri I. Aristov
提出了一种非平稳模型来描述“多孔基质中的盐”型复合吸附剂通过水与盐的相互作用在孔隙中形成盐溶液而从空气中吸附水分的过程。结果表明，在有效吸附速率常数不变的假设下，不能描述吸附器出口含水率的动态变化。分析了水吸附的限制步骤，认为限制步骤是水通过颗粒外表面附近形成的溶液层扩散。考虑到吸附速率常数随吸水量的增加而单调下降的情况，提出了吸附速率常数作为吸附剂含水量函数的表达式。测定了吸附极限阶段的有效扩散系数，该系数与氯化钙水溶液中的有效扩散系数接近。
A nonstationary model is proposed to describe the water sorption from air by composite sorbents of the “salt in a porous matrix” type via the interaction of water with the salt to form a salt solution in pores. It is shown that the dynamics of the moisture content at the adsorber outlet cannot be described under the assumption of constancy of the effective sorption rate constant. The limiting step of water sorption is analyzed, and it is supposed that the limiting step is the water diffusion through the solution layer forming near the external surface of a granule. An expression for the sorption rate constant as a function of the moisture content of the sorbent is proposed that takes into account the monotonic decrease in this constant with an increase in the amount of water sorbed. The effective diffusion coefficient at the limiting step of sorption is determined, which turns out to be close to the effective diffusion coefficient in an aqueous calcium chloride solution.