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http://hdl.handle.net/2282/221
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| Title: | Oxygen transfer and transport resistance across silicone tubular membranes |
| Authors: | Rathnasiri, Puhulwella Gamacharige
Ottøy, Magnar |
| Issue Date: | 2003 |
| Abstract: | Dissolved oxygen is used as an electron acceptor in aerobic organic waste digestion in
biological processes. To enhance production of intermediate metabolic products such as acetate in
anaerobic conversion, small amounts of oxygen is needed. The process is then called combined
microaerobic and anaerobic. One strategy of supplying oxygen is to dissolve it in water and transfer
it across a dense polymeric membrane to the biological medium. Thus experimental data on oxygen
flux and flow resistance are needed. In this study, an experimental method is proposed to determine
the transport rates and total resistance of flow across silicone tubular membranes by using bulk
oxygen concentration measurements. The biological medium inside the reactor is replaced by a
known volume of distilled water. Dissolved oxygen is removed from the distilled water by purging
nitrogen gas. Water to be circulated inside the membrane is saturated with oxygen by purging either
with pure oxygen or air. This oxygen saturated water is supplied to the reactor by flushing inside the
silicone tube. Experiments with different temperatures inside and outside the tubular membranes are
also performed. Variations of bulk oxygen concentrations with time inside the reactor are measured
using calibrated microelectrodes. At room temperature, both thin and thick membranes produced
the lowest oxygen transfer rate when water saturated with air was supplied inside the membranes.
The highest oxygen transfer rates were reported when pure air (not dissolved in water) was supplied
inside the membrane. When the reactor was held at 550C, both membranes showed a reduction of
oxygen transfer rates compared to the room temperature experiments. Results obtained can be used
as a tool to screen different membrane design options and estimate oxygen supply rates in
membrane integrated biological processes. |
| Keywords: | Dense tubular membranes
Dissolved oxygen
Membraner
Biological processes
Microaerobic
Flow resistance |
| Publisher: | Høgskolen i Telemark |
| Document type: | Report |
| URI: | http://hdl.handle.net/2282/221 |
| Appears in Collections: | HiT skrift
Institutt for prosess-, energi- og miljøteknologi
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