Enhancement of hydration rate of LiOH by combining with mesoporous carbon for Low-temperature chemical heat storage
Enhancement of hydration rate of LiOH by combining with mesoporous carbon for Low-temperature chemical heat storage
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DOI：
10.1016/j.applthermaleng.2019.01.049
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发表时间：
2019-03-05
影响因子：
6.4
通讯作者：
Matsuda, Hitoki
中科院分区：
文献类型：
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作者：
Kubota, Mitsuhiro;Matsumoto, Satoshi;Matsuda, Hitoki
氢氧化锂（LiOH）与一水氢氧化锂（LiOH中心点H2O）之间的可逆反应是373 K以下低温化学蓄热的理想选择，因为该体系可以在接近340 K的温度下储存热量，并具有1440 kJ/kg的高储存密度。然而，对于实际应用，有必要增强LiOH的水合速率，从而实现更高的放热速率。在这项研究中，我们专注于LiOH和介孔碳（MPC）的复合材料。预计LiOH将通过毛细管冷凝与MPC孔中冷凝的水分快速反应。LiOH/MPC复合材料通过浸渍法制备，使用1-10重量%的LiOH水溶液浓度和1-48小时的浸渍时间。结果表明，LiOH被成功地负载在MPC上，并且LiOH含量随着LiOH水溶液浓度的增加而线性增加。所有的LiOH/MPC复合材料在整个水合期间具有比单独的LiOH或MPC高得多的量的水合水。水合10分钟后的水合水和吸热的量的实验值和估计值的比较表明，在LiOH/MPC复合材料的情况下，大部分的LiOH在10分钟内水合。从这些结果可以看出，MPC负载的LiOH对提高LiOH的水合速率非常有效。
The reversible reaction between lithium hydroxide (LiOH) and lithium hydroxide monohydrate (LiOH center dot H2O) is promising for low-temperature chemical heat storage below 373 K, because this system can store heat at similar to 340 K with a high storage density of 1440 kJ/kg. However, for practical applications, it is necessary to enhance the hydration rate of LiOH and thus achieve a higher heat release rate. In this study, we focused on a composite of LiOH and mesoporous carbon (MPC). LiOH was expected to rapidly react with the moisture condensed in the pores of MPC by capillary condensation. The LiOH/MPC composite was prepared by an impregnation method using aqueous LiOH solution concentrations of 1-10 wt% and at impregnation times of 1-48 h. It was demonstrated that LiOH was successfully supported on MPC and that the LiOH content linearly increased with increasing aqueous LiOH solution concentrations. All LiOH/MPC composites had a much higher amount of hydrated water throughout the hydration period than did LiOH or MPC, individually. Comparison of the experimental and estimated values of the amount of hydrated water and endothermic heat after 10 min of hydration showed that most of the LiOH was hydrated within 10 min in the case of the LiOH/MPC composite. From these results, it was demonstrated that LiOH supported on MPC was very effective in improving the hydration rate of LiOH.