Kazuhiro Okabe

Separation of ethanol from ethanol/water mixtures by plasma-polymerized membranes from silicone compounds

Abstract The separation by pervaporation of ethanol/water mixtures was investigated. Plasma polymerization was used to produce membranes. Ethanol-permselective membranes can be prepared from various silicone and silane monomers under extremely mild polymerization conditions. These membranes have polydimethylsiloxane-like structures and selectivity factors of 1.5~5.2. Further investigations were carried out on the mechanism of permeation through plasma-treated silicone rubber membranes and silicone oil membranes. Highly permselective membranes can be prepared by surface treatment of thin polydimethylsiloxane membranes with silane compounds containing octadecyl groups. An ethanol permselectivity, αEtOH, of 18.0 and a flux of 0.015 kg/cm2-hr were obtained with these membranes. This report gives a novel method for producing ethanol-permselective membranes.

CO 2 capture and enrichment by novel hollow fiber facilitated transport membrane module with low energy consumption

Publisher Summary This chapter proposes a novel gas separation method using capillary membrane modules for simultaneous recovery and enrichment of CO2 in simulated flue gases. Several capillary membrane modules were fabricated with different dimensions and experiments were performed at several conditions by using an amine and an amino acid as the carriers of CO2. The energy consumption of the current process is compared to those of conventional gas absorption processes and membrane gas separation processes using polymeric membranes. Both a feed gas and a carrier solution are supplied to the feed side (high pressure side) of the capillary ultrafiltration membrane module and flow upward. Most of the carrier solution that contains dissolved CO2 permeates the membrane to the permeate side (low-pressure side), where the solution liberates CO2 to become a lean solution and the lean solution is returned to the lumen of the capillary module by a pump. Experiments were performed at several operational conditions by using diethanolamine (DEA) and 2, 3-diaminopropionic acid (DAPA) as carriers. The energy required for CO2 capture, enrichment, and liquefaction was about 0.27kWh kgC02-1, which is much lower than those by using polymeric membranes, conventional gas absorption processes consisting of absorption and stripping column. The proposed process is promising for the CO2 recovery with low energy consumption.