| 1. |
- Jönsson, Ann-Sofi, et al.
(författare)
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Fundamental principles of ultrafiltration
- 1990
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Ingår i: Chemical Engineering and Processing. - 0255-2701. ; 27:2, s. 67-81
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Tidskriftsartikel (refereegranskat)abstract
- Different theoretical models describing the influence of the operating parameters are treated in this paper. The osmotic pressure, gel layer and resistance in series models are presented. The influence of different operating parameters, such as the operating pressure, temperature, cross-flow velocity and concentration is demonstrated. The complex fouling phenomenon is reviewed. Finally, various pretreatment and cleaning operations are presented.
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| 2. |
- Jönsson, Ann-Sofi, et al.
(författare)
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Ultrafiltration applications
- 1990
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Ingår i: Desalination. - : Elsevier BV. - 1873-4464 .- 0011-9164. ; 77:1-3, s. 135-179
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Forskningsöversikt (refereegranskat)
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| 3. |
- Lipnizki, F, et al.
(författare)
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Applications of membrane processes in the beet and cane sugar production
- 2006
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Ingår i: Zuckerindustrie. - 0344-8657. ; 131:1, s. 28-38
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Tidskriftsartikel (refereegranskat)abstract
- Despite their success in different segments of the food industry, membranes are not well-established in the beet and cane sugar industry. A comprehensive overview on the potential applications of membranes in both the beet and cane sugar industry is given. The part on the beet sugar industry focuses on pulp press water recycling, pectin production from beet pulp, beet juice purification, demineralization of beet sugar juice and thin juice concentration. Potiential opportunities of membranes in cane sugar/cane refining industry are raw cane juice purification, clarified cane juice concentration, raw syrup purification, molasses treatment and decolorization of remelted raw sugar. Further, the ion-exchange resin regeneration waste recycling, sweet water concentration and evaporator condensate polishing are discussed. Overall, this article emphasizes the successes and potentials of membrane technology in the sugar industry.
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| 4. |
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| 5. |
- Lipnizki, F, et al.
(författare)
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Hydrophobic pervaporation: Influence of the support layer of composite membranes on the mass transfer
- 2002
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Ingår i: Separation Science and Technology. - 0149-6395. ; 37:8, s. 1747-1770
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Tidskriftsartikel (refereegranskat)abstract
- The opportunities of using hydrophobic pervaporation to concentrate organic components in aroma recovery and wastewater treatment have been recognized widely. The focus of this article is on the influence of the support layer on the mass transfer in hydrophobic pervaporation. Even though the influence of the support layer on the overall mass transfer has been observed experimentally, the modeling and analysis of this aspect has been widely neglected. The aim of this study is to build a bridge between modeling of the influence of the support layer and experimental data. Therefore, an improved modeling approach is proposed and used to analyze experimental data for the permeation of the two binary systems water-phenol and water-chloroform through hydrophobic composite polydimetylsiloxane membranes. Comparing the experimental results with the model, it has been observed that the mass transfer of the support layer depends on both physical and chemical properties of the support layer. On the basis of these observations, guidelines for the selection of support layers will be presented.
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| 6. |
- Lipnizki, F, et al.
(författare)
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Scale-up of pervaporation for the recovery of natural aroma compounds in the food industry. Part 1: simulation and performance
- 2002
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Ingår i: Journal of Food Engineering. - 0260-8774. ; 54:3, s. 183-195
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Tidskriftsartikel (refereegranskat)abstract
- The possibility of using pervaporation for the recovery of natural aroma compounds in the food industry has been widely recognised. The aim of this study was to build a bridge between experimental studies of multi-component systems and potential applications of pervaporation in the food industry. Therefore, a novel process simulation of pervaporation has been developed for multi-component mixtures. By applying this simulation to 10 aroma compounds of relevance in the food industry, the influence of process parameters such as permeate pressure, feed temperature, degree of aroma folding and membrane area, on the performance of pervaporation has been investigated. Based on the results of the simulations, it has been demonstrated that process simulation can play an important role in integrating and optimising pervaporation in the food industry.
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| 7. |
- Lipnizki, F, et al.
(författare)
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Scale-up of pervaporation for the recovery of natural aroma compounds in the food industry Part 2: optimisation and integration
- 2002
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Ingår i: Journal of Food Engineering. - 0260-8774. ; 54:3, s. 197-205
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Tidskriftsartikel (refereegranskat)abstract
- In this study the integration and optimisation of hydrophobic pervaporation for the recovery of natural aroma compounds in the food industry has been studied. The simulation developed in the first part of this study was applied to the design and scale-up of pervaporation units for the recovery of natural apple juice aroma. Both semi-batch and continuous process configurations were considered and the process conditions were optimised taking the cost of the process into account. For the semi-batch process, the cost per kg concentrated aroma was between 31.30 and 33.60 euro, depending on the membrane type. When returning the recovered aroma to the apple juice after heat treatment, the cost of aroma recovery per kg concentrate was between 0.31 and 0.34 euro. In the case of the continuous process, the cost for the apple juice aroma recovery was between 2.19 and 5.38 euro, while the cost of aroma recovery per kg apple juice was between 0.03 and 0.05 euro. Upon analysing the optimised processes with a sensitivity analysis of the key cost factors associated with pervaporation, membrane life-time and membrane cost, it was revealed that the membrane life-time is more important than the membrane cost and that the continuous process is more sensitive to changes in membrane life-time and membrane cost. Overall, this study revealed that pervaporation has the potential to become an alternative to conventional processes in recovering and concentrating aroma compounds in the food industry.
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| 8. |
- Marshall, A D, et al.
(författare)
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Influence of ionic calcium concentration on fouling during the cross-flow microfiltration of b-lactoglobulin solutions.
- 2003
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Ingår i: Journal of Membrane Science. - 0376-7388. ; 217:1-2, s. 131-140
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Tidskriftsartikel (refereegranskat)abstract
- The microfiltration (MF) fouling behaviour of -lactoglobulin solutions containing various levels of ionic calcium was investigated on a constant-flux, computer-controlled, cross-flow rig using zirconium oxide membranes. Fouling behaviour was highly dependent on both permeate flux and calcium concentration. At 200 l/(m2 h) on a 50 nm membrane the presence of 8.0 mmol/dm3 (8.0 mM) ionic calcium in the feed increased fouling resistance dramatically. The presence of 8.0 mmol/dm3 (8.0 mM) ionic calcium had little effect on protein transmission at 50 l/(m2 h) but decreased protein transmission dramatically from about 90% to about 10% at 200 l/(m2 h). Most of the additional fouling observed in the presence of calcium was reversible, i.e. removed by water flushing. In runs commenced without ionic calcium, addition of 8.0 mmol/dm3 (8.0 mM) ionic calcium after 1 h caused a rapid increase in fouling resistance and a rapid decrease in protein transmission. Similarly in runs commenced with 8.0 mmol/dm3 (8.0 mM) ionic calcium, changing to a calcium-free feed after 1 h caused a decrease in fouling resistance and an increase in protein transmission. Presumably calcium was leached from the deposited fouling layer causing it to "dissolve". The two dominant reactions responsible for these effects of permeate flux and ionic calcium on fouling by -lactoglobulin solutions are probably molecular unfolding by shear and calcium crosslinking.
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| 9. |
- Nilsson, Mattias, et al.
(författare)
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Influence of temperature and cleaning on aromatic and semi-aromatic polyamide thin-film composite NF and RO membranes
- 2008
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Ingår i: Separation and Purification Technology. - : Elsevier BV. - 1873-3794 .- 1383-5866. ; 62, s. 717-726
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Tidskriftsartikel (refereegranskat)abstract
- Although cleaning removes fouling, it may change the properties of membranes and consequently influence their performance. We have evaluated the combined effect of acidic/alkaline cleaning and temperature on the performance of two aromatic membranes, one a reverse osmosis membrane (HR98PP) and the other a nanofiltration membrane (NF90), two semi-aromatic polypiperazine membranes (NF200, NFT 50) and a Desal 5DK nanofiltration membrane. At the retention minimum of each membrane, the KCl retention and the water permeability were in the order: NFT 50
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| 10. |
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