气泡大小及相对湿度对鼓泡强化膜蒸馏的影响
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摘要
采用气液两相流技术强化高浓度NaCl溶液气扫式膜蒸馏(SGMD)系统.探究连续与间歇鼓泡法、气泡大小/相对湿度对鼓气强化SGMD过程性能的影响,并对比研究了间歇鼓泡与未鼓泡SGMD过程.结果表明:间歇鼓泡比连续鼓泡更利于强化MD过程;渗透通量随气泡相对湿度增加、气泡减小而增加.料液为饱和NaCl(333K)溶液时,鼓泡开/停组合为30s/3min时,气泡流速、相对湿度、气泡大小分别为0.7L/min、75%、0.22cm时,渗透通量达2.94L/(m~2·h);不同于未鼓气,间歇鼓气能有效延缓SGMD过程中通量急剧下降临界点的出现,膜表面的NaCl沉积物的微观分析也证实了此结果,且使热效率增加了79.52%.
Gas-liquid two-phase flow technology was employed to reinforce SGMD process with high-concentrated NaCl solution.The impacts of continuous and intermittent bubble method,bubble size/relative humidity on bubbling-enhanced SGMD process performance were investigated.Meanwhile,the comparative study of SGMD process with intermittent bubble and no bubble was carried out.It turned out that intermittent bubble was better than continuous bubble for optimization of MD(membrane distillation)process;The permeate flux increased with the increase of bubble relative humidity and the decrease of bubble size.When feed was saturated NaCl solution(333K),bubbling on-off set was 30s/3min,bubble flow rate/relative humidity/bubble size were 0.7L/min,75%,0.22 cm,respectively,permeate flux reached to 2.94L/(m~2·h).Relative to no bubble,intermittent bubble can delay the appearance of flux sharp flux decline in SGMD process,and NaCl deposition adherent to the membrane surface has verified the above results.Moreover,thermal efficiency was improved by 79.52%.
Gas-liquid two-phase flow technology was employed to reinforce SGMD process with high-concentrated NaCl solution.The impacts of continuous and intermittent bubble method,bubble size/relative humidity on bubbling-enhanced SGMD process performance were investigated.Meanwhile,the comparative study of SGMD process with intermittent bubble and no bubble was carried out.It turned out that intermittent bubble was better than continuous bubble for optimization of MD(membrane distillation)process;The permeate flux increased with the increase of bubble relative humidity and the decrease of bubble size.When feed was saturated NaCl solution(333K),bubbling on-off set was 30s/3min,bubble flow rate/relative humidity/bubble size were 0.7L/min,75%,0.22 cm,respectively,permeate flux reached to 2.94L/(m~2·h).Relative to no bubble,intermittent bubble can delay the appearance of flux sharp flux decline in SGMD process,and NaCl deposition adherent to the membrane surface has verified the above results.Moreover,thermal efficiency was improved by 79.52%.
引文
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[2]申龙,高瑞超.膜蒸馏技术最新研究应用进展[J].化工进展,2013,33(2):289-297.
[3]李国东,王薇,李凤娟,等.反渗透膜的研究进展[J].高分子通报,2010,7:37-42.
[4]候立安,刘晓芳.纳滤水处理应用研究现状与发展前景[J].膜科学与技术,2010,30(4):1-7.
[5]许亚夫,邹大江,熊俊.滤膜材料及微滤技术的应用[J].中国组织工程研究与临床康复,2011,15(16):2949-2952.
[6]高薇,武春恒.减压膜蒸馏及鼓气强化减压膜蒸馏过程性能的研究[A].第四届中国膜科学与技术报告会论文集[C].2010:564-568.
[7]高薇,于文静,武春瑞,等.鼓气强化循环气扫式没蒸馏过程研究[J].水处理技术,2011,37(3):96-104.
[8]Chen G,Yang X,Wang R,et al.Performance enhancement and scaling control with gas bubbling in direct contact membrane distillation[J].Desalination.2013,308:47-55.
[9]徐夫臣,潘艳秋,王同华.真空膜蒸馏海水淡化过程的强化研究[J].现代化工,2010,30(3):69-72.
[10]赵恒,武春瑞.鼓气减压膜蒸馏过程研究[J].水处理技术,2009,35(12):34-37.
[11]茂林,余立新,蒋维钧.膜蒸馏热效率的研究[J].水处理与技术,1992,4(18):225-229.