中空纖維模組滲透薄膜蒸餾進行葡萄糖濃縮之模擬與實驗探討

Simulation and experiment studies on concentrating glucose solution by osmotic membrane distillation with hollow fiber modules

徐聖婷(Sheng-Ting Hsu)

指導教授 ： 莊清榮

中原大學/工學院/化學工程研究所/碩士(2017年)

https://doi.org/10.6840/cycu201700549

摘要

於食品產業，液態食品常經濃縮程序以減少其包裝、儲藏和運輸成本，且能提高食品儲存之穩定性。近年來薄膜技術廣應用於食品工業上，基於滲透蒸餾(OD)可在常溫常壓下操作，較能保存食品中的營養物質，因此應用於食品濃縮甚有發展潛力。
本研究利用Matlab建立管式模組OD之通量模擬程式，並利用自組之管式PVDF模組及商業型PP中空纖維模組進行滲透蒸餾濃縮葡萄糖溶液實驗，探討操作條件如溫度、濃度對通量與濃縮度變化之影響，最後也進行滲透薄膜蒸餾實驗與模擬。
依據文獻操作條件模擬通量並與其實驗數據相比較，顯示兩者相對差距僅約0.2~2 %，確認了本研究所建立之模擬程式的可行性。自組PVDF模組之批次濃縮實驗，其汲取液為34 wt% 之氯化鈣溶液，葡萄糖進料初始濃度在16.8 wt%時，當溫度從25提升至45℃，通量由0.7上升至2 kg/m2hr，與模擬值之相對差異約為2 ~ 7 %。進一步以文獻常用45 wt% 之氯化鈣溶液為汲取液進行模擬，於35oC操作下，進料濃度從10提升至40 wt%，通量約降低9 %；當進料濃度為25 wt%，管長從10增加至30公分時，通量約降低2 %；因逆向流較能保持恆定的濃度差，通量約高於同向流0.7 %。
而PP中空纖維模組實驗，其進料液初始條件為10公升含19.1 %之葡萄糖溶液，45℃時10小時操作內平均通量僅為0.22 kg/m2hr，不同時間之通量測值與模擬值之相對差距約為1~7 %，雖通量低且會隨時間較明顯衰減，但因該模組面積達1.4m2，故經10小時濃縮操作後，進料槽葡萄糖濃度提升至23.9 wt%。而模擬每10小時重新置換11升之34 % 汲取液，操作40小時可將進料槽液之葡萄糖濃度從19.1提升到60.6 wt%，若無置換汲取液操作，操作40小時則僅提升到41.0 wt%。
最後以PVDF 模組進行滲透薄膜蒸餾批次濃縮葡萄糖溶液實驗，當兩側溫度為25℃時，通量為0.72 kg/m2hr，當進料溫度提高10℃時，通量為2.05 kg/m2hr，模擬與實驗的相對差距約在3~10 %間，顯示提高進料溫度對通量會有大幅度的提升。

關鍵字

滲透薄膜蒸餾 ； 模擬 ； 濃縮葡萄糖溶液

並列摘要

Concentration of liquid foods generally can significantly reduce the transport, packaging and storage costs and also make it has a greater stability in storage. Among the membrane technologies widely used in food industry, osmotic distillation (OD) which can be operated at room temperature and atmospheric pressure to preserve the nutritious characteristics of the food will have high potential in concentrating the liquid foods. In this study, OD with tube-based membrane modules for concentrating glucose solution was analyzed by experiments and simulation to investigate the effect of feed concentration, feed temperature and module characteristics on the flux and concentration factor.
A comparison between the OD flux simulated in the study and that measured from literatures was made first and showed the relative difference between both is only 0.2~2 %. Experiments using the self-assembly tubular PVDF module for batchwise concentration of 16.8 wt% glucose solution with draw solution of 34 wt % CaCl2 showed that average fluxes for 10 hrs operation increase from 0.7 to 2 kg/m2hr as temperature operated from 25 to 45℃. The fluxes simulated are about 2~7 % relative difference compared with the experimental data. Simulation results of the PVDF module with 45 wt % CaCl2 and at 35 ℃ showed that the flux decrease 9 % as glucose concentration of feed increases from 10 to 40 wt%. The flux simulated for 25 wt % glucose concentration showed 2% decrease as module length increase from 10 to 30 cm. With respect to the effect of flow in the module, simulation showed that the countercurrent flow has about 0.7 % higher flux that that with cocurrent flow.
Batchwise concentration experiments using Liqui-Cel® PP module with 10 L, 19.1% glucose solution and 11L , 34 % CaCl2 solution showed that the average flux is about 0.22 kg/m2hr for 10 hrs operation at 45℃. Since the PP module has an area of 1.4 m2, the glucose solution was concentrated to 23.9 wt% after 10 hrs of treatment. The simulation showed that glucose solution was concentrated from 19.1 to 60.6 wt% after 40 hours of continuous operation with periodical replacement of draw solution every 10 hrs. However, only 41.0 wt% concentrated solution was obtained without the replacement of draw solution.
Finally, osmotic membrane distillation (OMD) with PVDF module for concentrating glucose solution was also investigated. It appeared that the increase of feed temperature can result in an obvious increase of flux.
Experiments using Liqui-Cel® PP module showed that flux about 0.22 kg/m2hr at 45℃. However, the effect area of Liqui-Cel® PP module is 1.4m2, 10 liter glucose solution was concentrated from 19.1 to 23.9 wt% after 10 hours of treatment.
Batch experiments for concentrating glucose solution by osmotic membrane distillation (OMD), only 3~10 % error. The simulated results also indicated that more than 90% of mass transport resistance in the OD process is contributed from membrane layer.

並列關鍵字

osmotic membrane distillation ； simulation ； concentration glucose solutions

參考文獻

林弘家, 薄膜液體貫穿壓力的量測與管式直接接觸薄膜蒸餾之模擬及實驗探討, 碩士學位論文, 中原大學化學工程學研究所,桃園縣, (2014)

陳威廷, 滲透蒸餾濃縮葡萄糖溶液之模擬及實驗探討, 碩士學位論文, 中原大學化學工程學研究所,桃園縣, (2016)

沈岱蓉,管式直接接觸薄膜蒸餾之模擬及實驗探討, 碩士學位論文, 中原大學化學工程學研究所,桃園縣, (2015)

Alkhudhiri, A., Darwish, N., and Hilal, N., “Membrane distillation: A comprehensive review”, Desalination, 287 (2012) 2-18.

Awad, M., Janajreh, I., and Fath, H., “Low Energy Direct Contact Membrane Distillation Towards optimal flow configuration”, Renewable and Sustainable Energy Conference (IRSEC'2013) 471-476.