Reverse Osmosis System Analysis

ROSA [Reverse Osmosis System Analysis] 6 only projects reverse osmosis and nanofiltration system performance from a User-controlled set of data input and design decisions. The... 

Dow Water Solutions-FilmTec (Minneapolis, MN) www.dow.com Reverse Osmosis System Analysis (ROSA)... 

Gill, W.N. and Bansal, B., Hollow fibre reverse osmosis systems Analysis and design. AIChE J., 19, 823, 1973. 

Gupta, S. K. (1987). Design and analysis of a radial-flow hollow-fiber reverse-osmosis system. Ind. Eng. Chem. Res. 26, 2319-2323,... 

Soltanieh, M., and Gill, W. N. (1982). Analysis and design of hollow fiber reverse osmosis systems. Chem. Eng. Commun., 18, 311-330. 

The above equations show that for a reverse osmosis system specified In terms of y, 9, and X, any one of the six quantities (performance parameters) C], C2, C3, C3, X or X or T, and A uniquely fixes all the other five quantities (112). Further, since the relationships represented by the set of eq 34 to 41 Involve 8 equations with 12 unknowns, namely, y, 9, X, Z, A, C-j, C2, C2, C3, C3, C3 and X or X or T, by fixing any four Independent quantities Included In the above unknowns, eq 34 to 41 can be solved simultaneously to obtain the remaining 8 quantities. The utility of this approach to system analysis for reverse osmosis process design and predicting the performance of reverse osmosis modules Is Illustrated In detail In the literature (6d,105,107,108,111,112,113). 

S. Jain, S.K. Gupta, Analysis of modified surface pore flow model with concentration polarization and comparison with Spiegler-Kedem model in reverse osmosis system, J. Membr. Sci. 232 (2004) 45-61. 

Reverse osmosis is simply the application of pressure on a solution in excess of the osmotic pressure to create a driving force that reverses the direction of osmotic transfer of the solvent, usually water. The transport behavior can be analyzed elegantly by using general theories of irreversible thermodynamics however, a simplified solution-diffusion model accounts quite well for the actual details and mechanism in most reverse osmosis systems. Most successful membranes for this purpose sorb approximately 5 to 15% water at equilibrium. A thermodynamic analysis shows that the application of a pressure difference, Ap, to the water on the two sides of the membrane induces a differential concentration of water within the membrane at its two faces in accordance with the following (31) ... 

Carta JA, Gonzales J and Subiela V (2003), Operational analysis of an innovative wind powered reverse osmosis system installed in the Canary Islands , Sol Energy, 75,153-168. 

In all the foregoing discussion on reverse osmosis transport, system analysis and process design, no new chemical engineering principle Is Involved. But the manner In which the known principles are combined and expressed Is new the kind of results arising from such expressions Is new and the direction such approach sets for future work on the subject Is also new, all of which open a new area of chemical engineering. 

Reverse osmosis for concentrating trace organic contaminants in aqueous systems by using cellulose acetate and Film Tec FT-30 commercial membrane systems was evaluated for the recovery of 19 trace organics representing 10 chemical classes. Mass balance analysis required determination of solute rejection, adsorption within the system, and leachates. The rejections with the cellulose acetate membrane ranged from a negative value to 97%, whereas the FT-30 membrane exhibited 46-99% rejection. Adsorption was a major problem some model solutes showed up to 70% losses. These losses can be minimized by the mode of operation in the field. Leachables were not a major problem. 

Other grades of water may be present in parenteral facilities for use as initial rinses and detergent cleaning. The water utilized for these purposes is generally of relatively low bioburden and is often deionized, softened, ultra-filtered, or in some instances prepared by distillation or reverse osmosis, resulting in chemical purity similar to, if not identical to, WFI. Systems for the preparation of this water are subject to qualification, validation, and routine analysis to assure consistent quality. 

Ion exchange desalination - DESAL , SIROTHERM Membrane desalination - Reverse Osmosis, Electrodialysis Continuing fixed bed counterflow development Condensate polishing systems Ion Chromatography analysis, and Pellicular resins Polymeric adsorbents... 

Recommcndation 4-1. To avoid the possibility of unanticipated disposal problems, the PMACWA and the BGCAPP contractor should characterize and consider waste management options for reverse osmosis rejectate brine, supercritical water oxidation (SCWO) filtrate solid waste, SCWO titanium tank liners, venturi scrubber particulate filters, and energetics offgas treatment system filters before submitting the waste analysis plan required by RCRA. The PMACWA should also look carefully for any as-yet-unidentified secondary waste streams from BGCAPP or PCAPP. 

Previous work with aqueous solution systems has been successful In treating both completely Ionized salts as well as Incompletely Ionized salts (, 6). This work Incorporates both of these cases In methanol solutions and uses the Klmura-Sourlrajan analysis for the treatment of reverse osmosis data (.7). The surface excess free energy parameters (.-tAG/KT) for the Ions and Ion pairs Involved were determined by the methods established earlier (8). The predictability of membrane performance by the use of data on free energy parameters obtained In this work has been tested. 

Water samples from various sources can also be analyzed (Parkinson et al., 1982) such as tap-water from patients on home dialysis. Water used to prepare dialysate solutions should be checked as a possible source for introducing aluminium into the dialysis system. Aluminium-free water for the preparation of standards, solutions and dilutions for analysis can be achieved by distilling, deionizing, passing through reverse osmosis, or a combination of the three. Analysis of this type of water should result in no detectable levels of aluminium (Smeyers-Verbeke et al., 1980). 

Experimental measurements of RED and PRO system performance are limited. However, a recent techno-economic analysis [143] suggests where the processes possess the greatest potential. RED is most attractive when using seawater as the concentrated salt solution while PRO is most attractive for more concentrated brines. An intriguing application is the use of PRO to recover energy from the concentrated brines produced by reverse osmosis desalination. 

Once the feed water source has been determined, analysis of the feed water composition is necessary before a treatment system can be designed. Feed water constituents that must be analysed prior to designing a RO/NF membrane system as per ASTM Designation D4195-88 Standard Guide for Water Analysis for Reverse-Osmosis Applications are discussed in Chapter 6. Typical water treatment methods are summarised in Table 2.2. 

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