The development of a bench-scale fluidized bed reactor for thermochemical energy storage under partial vacuum

太阳能热能可以满足加拿大住宅供暖和热水需求的很大一部分；然而，目前太阳能热技术在加拿大的普及受到限制，因为在日照较少的采暖季节需要大量的储热系统。与在液态水中储存显热所需的传统大型储罐相比，固体吸附剂材料与气相水之间的热化学反应具有更高的能量储存密度，提供了更紧凑和无损耗的储热解决方案。通过吸附进行的热化学储存是间接的，在吸附过程中，当水蒸气与吸附剂表面结合时释放出焓。将饱和材料置于吸附过程中释放的等量热量下，将打破这些键（解吸），使材料再生，进行进一步的吸附-解吸循环。利用固定床反应器在常压下对包括合成沸石在内的吸附剂进行了研究，并在这些材料的高能量储存密度和长寿命周期方面取得了可喜的结果。该研究计划将遵循在NSERC参与期间成功确定的未来工作建议，并将探索压力和流化对沸石13X吸附的影响，以应用于低温热能储存。预计在较低的反应器温度下，在反应器内的部分真空条件下，可以实现更快的脱附，并且反应器内压力的逐渐降低将延长吸附过程中热量的释放。作为固定床设计的延伸，预计流化将改善气固之间的传热和传质。在用多物理场软件对实验级流化床反应器的综合模型进行模拟后，将搭建实验装置，分别在正、负（真空）表压下观察沸石13X的吸附和解吸。

A significant portion of Canadian residential space heating and hot water needs can be met with solar thermal energy; however, the penetration of solar thermal technology in Canada is currently limited by the sizable thermal storage systems that are required during the heating season when solar insolation is low. In comparison to the conventionally large tanks required for storing sensible heat in liquid water, thermochemical reactions between solid adsorbent materials and water in the gas phase possess much higher energy storage densities, providing a more compact and loss-free thermal storage solution. Thermochemical storage via sorption is indirect, where enthalpy is released when water vapour bonds with the surface of an adsorbent during adsorption. Subjecting the saturated material to an equal amount of heat as that released during adsorption will break those bonds (desorption), regenerating the material to undergo further adsorption-desorption cycles. Adsorbents including synthetic zeolites have been investigated using fixed bed reactors at atmospheric pressure and promising results have been obtained with respect to the high energy storage densities and long life cycle of these materials. This research program will follow recommendations made for future work identified during a successful NSERC Engage period, and will explore the effects of pressure and fluidization on the sorption of zeolite 13X for the application of low-temperature thermal energy storage. It is expected that faster desorption at a lower reactor temperature can be achieved under a partial vacuum in the reactor, and that a gradual reduction of pressure in the reactor will prolong the release of heat during adsorption. As an extension of the fixed bed design, it is expected that heat and mass transfer between the gas and solid will be improved with fluidization. After a comprehensive model of a bench-scale fluidized bed reactor has been simulated in a multiphysics software, an apparatus will be constructed for an experimental phase in which the adsorption and desorption of fluidized zeolite 13X will be observed under positive and negative (vacuum) gage pressure respectively.