1991 Fiscal Year Final Research Report Summary
Separation of supercritical fluid mixtures with a membrane process
| Project/Area Number |
02453111
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
化学工学
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| Research Institution | Department of material science and chemical engineering, Yokohama National University |
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Principal Investigator |
OHYA Haruhiko Yokohama National University, Professor, 工学部, 教授 (40017950)
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| Co-Investigator(Kenkyū-buntansha) |
MATSUMOTO Kanji Yokohama National University, Professor, 工学部, 教授 (30011224)
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| Project Period (FY) |
1990 – 1991
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| Keywords | Membrane / Gas separation / Supercritical fluid / Polyimide / Polyamic acid / Asymmetric / High temperature |
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| Research Abstract |
Asymmetric polyamide Kapton^R membrane was made by casting a solution of 18 wt% polyamic acid and 5 wt% phenanthrene in dimethylacetainide at 70ﾟC with a four-minutes evaporation time. Usine this membrane, a separation factor alpha_<ethanol/CO2>, 8.7 was obtained at 373 K and 15 MPa and 6.5 at 423 K and 15 MPa for the experimemt involving the separation of gaseous mixtures Of CO_2 and ethanol with a concentration ratio of 15 : 1. Its value at 373 K is 1.3 times higher than at 423 K, and increases with total pressure, while the separation factor at 423 K remains constant with pressure.
The activation energies of permeability were 2.6 kj/mol for ethanol and 7.1 kj/mol for supercritical CO_2・These values are very small compared to those of 48 kj/mol for ethanol and 25 kj/mol for CO_2 with the symmetric polyamide membrane. Supercritical fluid permeation experiment might be the best method to determine the permeation mechanism whether pore flow model or solution-diffusion model, from the measurement of activation energy of permeation.
From the data obtained, a calculation was carried out to determine the required membrane area for 90% recovery of ethanol from mixtures with an initial concentration of 1 mol% and a feed rate of 36 mol/h. This area is 0.82 m^2 for separations conducted at 10 MPa and 373 K and 0.28 m^2 at 15 MPa and 373 K. And three quarters of operating energy of pressurization might be saved. Therefore, the process integrated with membrane recovery could save operating energy about 3/4 and the size of the main compressor will be reduced to 1/4 theoretically.
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Research Products
(10 results)
