水分对分子筛结构及吸附性能的影响

分子筛是变压吸附制氧过程中最重要的组分,使用中该组分常出现吸水失效问题,极大地影响了氧产量及浓度.针对此问题,本文以HD-1型和PU-8型分子筛为原料,通过在不同温度(100、200、300、400℃)下活化得到不同含水量的分子筛,并通过对不同材料的结构形貌、热性能及吸附性能的表征分析了水分对分子筛结构及吸附性能的影响.研究结果表明:水分不会破坏分子筛的骨架结构,但会增大晶胞参数,并导致HD-1型分子筛中阳离子迁移;分子筛中的物理吸附水和化学结晶水会影响其吸附性能,其中物理吸附水的影响最大;活化有效提高了分子筛的吸附性能,且温度越高,含水量越少,吸附性能越好;在150~180℃下活化,将物理吸附水脱附后,分子筛的吸附能力可恢复70%,可在此温度下进行吸附器内低温活化;在400℃下活化,脱除化学结晶水,分子筛吸附性能可100%恢复,400℃为两种分子筛的最佳活化温度.

Effects of water on structure and adsorption performance of molecular sieve

Molecular sieve is the most important component in the process of pressure swing adsorption, it often losts its capability of water adsorption, which results in a significant impact on the oxygen production and concentration. To solve this problem, this paper introduces a method to activate failure HD-1 and PU-8 molecular sieves at different temperatures (100, 200, 300, 400℃). The effects of water on the structure and adsorption properties of molecular sieves were invesitgated by macroscopical morphology, microcosmic morphology analysis, thermal properties and adsorption capacity test. It shows that, water does not destroy the framework of molecular sieves, but it increases the unit cell parameters and leads to the migration of Li cations in the HD-1; the activation improves the adsorption capacity of the molecular sieve, and the higher the temperature, the lower adsorption water content is, the better the adsorption performance ;there are physical and chemical water in molecular sieves that affects the adsorption capacity, and especially physical adsorption;activation at 150~180 ℃, will be attached and physical adsorption water, adsorption capacity of zeolite can be recovered to 70%. So activation in adsorbent can be carried out at this low-temperature; the removal of chemical crystal water , the adsorption properties of zeolites can be recovered to 100%, 400 ℃ is the best activation temperature of two kinds of molecular sieve.