Grace Membrane Systems

CA blend membranes for gas separation are commercially available from Envlrogenlcs Systems Co. (El Monte, CA), Separex Corp. (Anaheim, CA) and Grace Membrane Systems (Houston, TX), and are applied In spiral-wound modules for the separations of acidic gaseous components from natural gas, for the recovery of carbon dioxide In enhanced oil recovery processes for gas dehydration or the separation of hydrogen from carbon monoxide (21-23). 

Separex s,41-43 Grace Membrane Systems cellulose ester,60 Envirogenics GASEP (trademark of Envirogenics Company)64 cellulose triacetate spiral-wound membranes, and Dow cellulose acetate hollow fibers are used to produce a salable product from sour gas streams. 

Grace Membrane Systems became Kvaemer Membrane Systems in 1994. 

Use of nanofiltration for non-aqueous separations is limited by membrane compatibility - a common material in composite nanofiltration membranes used for aqueous separations is polysulfone which possesses limited solvent resistance [134]. However, during the past two decades a number of materials have emerged with improved solvent resistance that have enabled a broad range of organic solvent nanofiltration (OSN) applications. These materials include polydimethylsiloxane, polyphenylene oxide, polyacrylic acid, polyimides, polyurethanes, and a limited number of ceramics. Commercial products are offered by Koch Membrane Systems, W.R. Grace, SolSep, and Hermsdorfer Institut fur Technische Keramik (HITK) [135]. 

Membrane systems to remove acid gas from the natural gas emerged more than three decades ago. Today about half a dozen venders provide membrane systems for natural gas upgrading. Amongst them are UOP (Separex and Grace), who uses cellulose acetate spiral wound module and Natco (Cynara) who uses cellulose acetate hollow fiber membrane modules. Ube, Air Liquide and Air Products offer polyimide hollow fiber membrane modules, and MTR produces perfluoropolymer membranes in spiral wound modules. 

Adds, A. Lim, C. Grace, J. The Fluidized Bed Membrane Reactor System A Pilot-Scale Experimental Study Chemical Engineering Science 49, No. 24B (1994) 5833-5843. 

H.M. Adris, C.J. Lim and J.R. Grace, The fluidized bed membrane reactor system A pilot-scale experimental study. Paper presented at ISCRE 13, September 1994, Baltimore, MD, USA. 

A 1989 report by Grace [12] compared the economics of amine and membrane processes for natural gas treating for 3, 10, 30, 37, 60, 100, 104, 140 and 148MMSCFD (90(X)0 to 4440000mVday) scale systems. Costs for membrane/amine hybrid systems were also considered. The median system size in this collection of proposed applications is 60MMSCFD (1800000mVday). 

For new system builds the same strategy can be done with spiral wound modules designed for natural gas treatment. Grace has constructed a 30-cm (12-inch) diameter module versus the standard 20-cm (8-inch) diameter module. Since membrane area is a squared function of diameter, the ratio of 144 to 64 means a 225% increase in membrane area per module. Although the larger diameter modules and pressure housings each cost more there is potential for reduction in total system cost. 

Adris, A. M., Grace, J. R. (1997). Characteristics of fluidized-bed membrane reactors scale-up and practical issues. Industrial Engineering Chemistry Research, 36, 4549—4556. Adris, A. M., Grace, J. R., Lim, C. J., Elnashaie, S. S. (1994). Fluidized bed reaction system for steam/hydrocarbon gas reforming to produce hydrogen. Patent no. 5326550. 

Adris AEM, Lim CJ, Grace JR The fluidized bed membrane reactor system a pilot scale experimental study, Chem Eng Set 49 5833—5843, 1994. 

GRACE Systems Cellulose acetate membranes are also used in spiral-wound configuration. Their data, reproduced in Figures 10.16,10.17, and 10.18, indicate that the permeability, defined as mol/m s kPa, increases with an increase in transmembrane pressure, for both methane and CO2. However, the... 

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