Performance enhancement of a submerged vacuum membrane distillation (S-VMD) system using low-power ultrasound
Performance enhancement of a submerged vacuum membrane distillation (S-VMD) system using low-power ultrasound
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DOI：
10.1016/j.memsci.2020.119004
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发表时间：
2021-03-01
影响因子：
9.5
通讯作者：
Phelan, Patrick
中科院分区：
文献类型：
--
作者：
Bamasag, Ahmad;Daghooghi-Mobarakeh, Hooman;Phelan, Patrick
浸没式真空膜蒸馏（S-VMD）是一种热驱动的高盐脱盐工艺。搅拌技术，如曝气和循环已被用来提高渗透通量，并减轻温度和浓度极化的影响，在S-VMD的一个主要缺点。在这项研究中，S-VMD系统，使用超声波能量作为搅拌技术的建议。实验研究了超声功率和频率在不同料液温度和浓度下的影响。结果表明，在相同的操作条件下，施加低功率超声波可以提高渗透通量高达24%，与相同的过程相比，没有超声波能量。超声强化效果随超声功率的增大、频率的降低、料液温度的降低和料液浓度的增加而增强。研究了超声强化传热传质的可能机理，并根据渗透通量随频率的变化规律，认为超声强化传热传质主要是声空化作用的结果。超声波辅助的S-VMD系统在相对长的运行时间内保持了稳定的渗透通量和优良的水质，表明超声波能量是一种有前途的和安全的方法，以提高渗透通量在S-VMD系统。
Submerged vacuum membrane distillation (S-VMD) is a thermally driven separation process capable of desalinating water with high salt concentration. Agitation techniques such as aeration and circulation have been used to enhance the permeate flux and to mitigate the effect of temperature and concentration polarizations, a major drawback in S-VMD. In this study, an S-VMD system that uses ultrasonic energy as an agitation technique is proposed. The effects of ultrasonic power and frequency under different feed temperatures and concentrations were investigated experimentally. Results show that applying low-power ultrasound can improve the permeate flux up to 24% compared to the same process without ultrasonic energy under the same operating conditions. The ultrasound-assisted enhancement increases with higher ultrasonic power and lower frequency, as well as lower feed temperature and higher concentration. Possible heat and mass transfer enhancement mechanisms associated with integration of ultrasound were investigated and based on the variation of the permeate flux with frequency, the enhancement was mainly attributed to acoustic cavitation. The ultrasonic-assisted S-VMD system maintained a stable permeate flux and excellent water quality over a relatively long-term operation, indicating that ultrasonic energy is a promising and safe method to enhance the permeate flux in S-VMD systems.