Air with carbon dioxide is bubbled through Photobioreactors (PBRs) to add carbon dioxide to the reactor medium, remove oxygen, and mix the medium. Most PBR systems use various types of spargers/diffusers that consist of straight or curved tubes with perforation in them to inject air into the PBR reactor volume. A possible novel approach to introducing air into the PBR reactor volume is to use a plenum under the PBR reactor volume in conjunction with a porous membrane that separates the air in the plenum from the liquid medium in the reactor volume. The resistance offered by the porous membrane and the liquid in the reactor volume to air flow needs to be established so that power requirements to provide the desired air flow through the PBR can be determined. Four types of porous membranes were tested: 1)Sintered High Density Polyethylene HDPE 1.59 mm thick with 15–45 μm pore size, 2) Sintered HDPE 0.79 mm thick with 20μm pore size, 3) Genpore black plastic sheet with 45 μm pore size, and 4) Porex 7896 HDPE with pore size of 35 μm). Specimens were tested in a 76.2 mm inside diameter reactor with a depth of 304.8mm and a 76.2 mm plenum depth. Water was used as the reactor medium and the depth was varied between 0 and 228.6 mm. Results showed that the Porex 7896 membrane had little resistance to air flow when the water depth was 0.0mm (1–22 Pa), 1–200 Pa for the Genpore plastic sheet, 1200–1400Pa for the Porex with 20μm pores, and 1100–2500 Pa for the Porex with the 15–45 μm pore sizes for superficial air velocities between 0.00345 m/s to 0.0242 m/s. Water depth was then increased to 228.6 mm in 25.4 mm increments and tested with the same air flow rates. The addition of water significantly increased the resistance to air flow for all membranes (highest being 4200 Pa). Least square correlations for the membranes using water depth and superficial air velocity indicate that resistance to air flow of the membranes was linear with superficial velocity but parabolic with water depth.
- Advanced Energy Systems Division
Experimental Determination of Pressure Loss Through Porous Membranes
Anderson, GA, Kommareddy, A, Gu, Z, Puetz Anderson, J, & Gent, SP. "Experimental Determination of Pressure Loss Through Porous Membranes." Proceedings of the ASME 2014 8th International Conference on Energy Sustainability collocated with the ASME 2014 12th International Conference on Fuel Cell Science, Engineering and Technology. Volume 2: Economic, Environmental, and Policy Aspects of Alternate Energy; Fuels and Infrastructure, Biofuels and Energy Storage; High Performance Buildings; Solar Buildings, Including Solar Climate Control/Heating/Cooling; Sustainable Cities and Communities, Including Transportation; Thermofluid Analysis of Energy Systems, Including Exergy and Thermoeconomics. Boston, Massachusetts, USA. June 30–July 2, 2014. V002T04A010. ASME. https://doi.org/10.1115/ES2014-6460
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