Permasep permeators

Fig. 13. Du Pont hoUow fine fiber Permasep permeator.

Successful Operation of a Permasep Permeator Reverse-Osmosis System on Biologically Active Feed Water... 

A "Permasep" permeator reverse osmosis (RO) installation, capable of producing 1500 cubic meters of product water per day, was successfully operated for six months with RO feed water drawn from cUi estuary cuid having 1200 to 1400 mg/H total dissolved solids (TDS). 

C.P. Shields, Five Years Experience with Reverse Osmosis Systems using DuPont Permasep Permeators, Desalination 28, 157 (1979). 

Membrane research and development started in Du Pont in 1962 and culminated in the introduction of the first B-9 Permasep permeator for desalination of brackish water by reverse osmosis (RO) in 1969. The membrane in this B-9 Permasep module consisted of aramid hollow fibers. In 1969, proponents of RO technology had ambitious dreams and hopes. Today, RO is a major desalination process used worldwide to provide potable water from brackish and seawater feeds. Du Font s membrane modules for RO are sold under the trademark Permasep permeators. The RO business is a virtually autonomous profit center that resides in the Polymer Products Department. The growth and success of the Permasep products business is a direct result of Du Font s sustained research and development commitment to polyamides, a commitment that dates back to the 1930 s and the classic polymer researches of Wallace H. Carothers. Since 1969, improved and new Permasep permeators have been introduced six times, as shown in Table I. 

Du Pont does not currently market Permasep permeators for gas separations. They did, however, in the B-1 Permasep permeator, introduce the first commercial, hollow fiber permeator for gas separations. This permeator employed hollow fibers of polyethylene terephthalate as the membrane. Later, permeators having aramid hollow fiber membranes were field tested for hydrogen separations. Du Pont is presently actively engaged in research for the development of membrane technology for a wide variety of applications. 

This brief historical summary of Permasep permeator developments introduces the subject of structure-property relationships for membranes from aromatic polyamides and derivatives. 

The membranes in Du Font s B-9 and B-10 Permasep permeators consist of bundles of aramid hollow fibers. A drawing illustrating the construction of B-9 and B-10 modules is shown in Figure 8 (23, 24). 

Specifications for B-9 and B-10 Permasep permeators are given in Du Font s PEM (Permasep Engineering Manual) (23) and in Du Font s Hollow Fiber Membranes (24). These references also... 

Cutaway views of permeators (e) spiral-wound separator [6y permission, from W. Eykamp and J. Steen, in Handbook of Separation Process Technology, R. W. Rousseau ed.), Wiley, 1987, p. (i) PERMASEP hollow-fiber separator by permission, from Du Pont brochure, PERMASEP Permeators, 1990). 

Water treatment systems have now come to include plastics, such as Du Pont s Permasep permeators for reverse osmosis (RO) water desalination, introduced in 1969 (see Figs. 12-5 and 12-6). Since that time such systems have been used in thousands of installations around the world for desalination of brackish water and seawater and to treat waste effluents. These permeators come in four product types, according to the type of water to be treated (see Table 12-1). 

Figure 12-5. Du Font s hollow, fine-fiber Permasep permeator for reverse-osmosis water desalination.

Table 12-1. Du Font s Permasep Permeators Based on the Type of Water to be Treated...

Fifty years ago, the SDI test was developed to predict the fouling tendency for the DuPont Permasep Permeators (hollow fine fiber RO elements). The SDI test is still the standard method for fouling prediction on spiral... 

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