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作为一种化学吸附制冷工质对,在吸附制冷条件下,CaCl2-NH3在发生化学吸附之前,由于van der waals力相对于化学反应力作用距离比较长,所以一般要先发生物理吸附. 这个状态称为化学吸附前驱态.通过控制氯化钙不同的膨胀、结块现象,在氯络合物的屏蔽系数作用下实现NH3气体分子与Ca2+之间不同的距离长度,从而得到了不同的化学吸附前驱态.结果表明,吸附剂发生严重膨胀现象而没有发生结块现象时,由于化学吸附前驱态中NH3气体分子与Ca2+之间距离较长,吸附过程所需要的活化能增加,吸附剂在反复的吸附、解吸过程中出现衰减现象.而在吸附剂发生结块现象时,由于NH3气体分子与Ca2+之间距离受到有限空间的控制,从化学吸附前驱态过渡到化学吸附态所需要的活化能相对较小,其吸附性能不再出衰减趋势.利用化学吸附前驱态研究了吸附制冷等压线,结果也表明,在Ca2+的分布没有对NH3气体分子的渗透性能产生影响的前提下,化学吸附前驱态对试验结果起着决定性作用.
As a chemical adsorption refrigeration working pair, under the condition of adsorption refrigeration, before the chemical adsorption occurs, CaCl2-NH3 generally needs to be physically adsorbed before the chemical van der waals force is relatively long due to its chemical reaction force. Known as chemisorption precursor.Calcium chloride by controlling the different expansion, agglomeration phenomenon, in the chlorine complex under the shielding factor to achieve NH3 gas molecules and Ca2 + distance between the different lengths, resulting in different chemisorption The results showed that when the agglomeration of adsorbent did not occur during the agglomeration, the activation energy required for the adsorption process increased due to the longer distance between NH3 gas molecules and Ca2 + in the precursor of chemisorption, Of the adsorption and desorption process decay phenomenon occurred in the adsorbent caking phenomenon, due to the NH3 gas molecules and Ca2 + distance controlled by a limited space, from the chemical adsorption precursor state transition to the chemical adsorption state of the required activation energy Is relatively small, the adsorption performance no longer decay trend.The adsorption isotherm was studied by chemisorption precursor, the results also showed that in Ca2 + Under the premise of no influence on the distribution of the permeability NH3 gas molecules chemisorbed precursor state results plays a decisive role.