过程参数对采用多孔陶瓷超滤膜回收烟气中余热和水性能的影响

Effects of process parameters on water and waste heat recovery from flue gas using ceramic ultrafiltration membranes

将孔径为20 nm的陶瓷膜组装制成膜冷凝器,在水蒸气-空气形成的模拟体系中,采用去离子水作为冷却介质,开展了传递膜冷凝技术在烟气除湿和工业余热综合应用方面的研究。考察了空气流量、冷却水流量、进气温度和冷却水温度对陶瓷内膜和外膜过程通量的影响,并比较了两者水热回收性能。结果表明,过程通量均随进气流量和进气温度的增大而增加。随着冷却水流量的增大,过程通量也不断增加,但是冷却水流量达到一定值后,过程通量基本不再变化。冷却水温度对过程水通量的影响较小,但是热通量对冷却水温度的改变较敏感。冷却水流量的变化对陶瓷外膜的过程通量影响更加显著,表明陶瓷外膜水热回收过程更易受流体边界层的影响。在各实验工况范围内,陶瓷内膜和外膜分别具有更高的热通量和水通量,采用陶瓷膜过程的水通量和热通量最高分别可达到23.1 kg·m^(-2)·h^(-1)和47.5 MJ·m^(-2)·h^(-1)。随着传递膜冷凝技术开发和研究的不断深入,该技术在除湿和工业余热综合应用领域有着广阔的发展空间,将为我国节水、节能以及环境保护等领域的发展提供新的解决思路。

A membrane condenser was established by using tubular ceramic membranes with a separation layer of 20 nm in pore size, which are coated on the inner/outer-side of the tube（IM/OM）, respectively. Experiments of water and heat recovery from simulated flue gas were conducted using deionized water as coolant. Effects of air flow rate, cooling-water flow rate, inlet gas temperature and inlet water temperature on mass and heat transfer across the IM and OM were investigated. Results showed that both water and heat fluxes of IM and OM increased as the increment of the air flow rate and inlet gas temperature. Water and heat fluxes of both IM and OM increased as the cooling-water flow rate elevated, while this tendency of variation was not remarkable when the cooling-water flow rate reached a certain value. Reducing the inlet water temperature effectively enhanced heat fluxes of IM and OM, but had little effect on water fluxes. The influence of coolant water flow rate on water and heat fluxes of OM is more significant, indicating that mass and heat transfer across the OM was more susceptible to the boundary layers effect. Compared with the IM,the OM exhibited much higher water fluxes and lower heat fluxes. In this work, water and heat fluxes of ceramic membranes were up to 23.1 kg·m（-2）·h（-1） and 47.5 MJ·m（-2）·h（-1）, respectively. With the development of the TMC, it has broad application in dehumidification and utilizing industrial waste heat. This technology will also bring new ideas in many fields such as energy and water conservation and environmental protection.