Membrane filtration module cost

The objective of the present study is to develop a cross-flow filtration module operated under low transmembrane pressure drop that can result in high permeate flux, and also to demonstrate the efficient use of such a module to continuously separate wax from ultrafine iron catalyst particles from simulated FTS catalyst/ wax slurry products from an SBCR pilot plant unit. An important goal of this research was to monitor and record cross-flow flux measurements over a longterm time-on-stream (TOS) period (500+ h). Two types (active and passive) of permeate flux maintenance procedures were developed and tested during this study. Depending on the efficiency of different flux maintenance or filter media cleaning procedures employed over the long-term test to stabilize the flux over time, the most efficient procedure can be selected for further development and cost optimization. The effect of mono-olefins and aliphatic alcohols on permeate flux and on the efficiency of the filter membrane for catalyst/wax separation was also studied. 

Polymeric membrane elements and modules which consist of elements come in different sh4>es. The shape strongly determines the packing density of the element or module which is indicative of the available membrane filtration area per unit volume of the element or module the packing density, in turn, can affect the capital and operating costs of the membranes. The packing density is often balanced by other factors such as ease and cost of maintenance and replacement, energy requirements, etc. Most of the polymeric membranes are fabricated into the following forms tube, tubes-in-shell, plate-and-frame, hollow-fiber, and spiral-wound. 

The costs of the filtration processes include module and energy cost. The module cost depends on the membrane area (inversely related to flux), so the module cost per unit filtrate can be calculated by... 

The DMF module (PaU Corp., New York) which consists of several disks mounted on the same shaft [2, 135]. The reported studies of the apphcation of the rotating disk dynamic membrane indicate that high shear-induced filtration is much less sensitive to the solids concentration. Advantage of the rotational system is that it permits operation at both very low transmembrane pressure-drop, and low upstream mass velocity, without loss in depolarization efficiency. It is thus possible with this system to achieve cleaner separation of solute components, than is achievable with conventional systems. Equipment for this process is, unfortunately, significandy more costly, and maintenance costs much higher also, than those for conventional membrane systems. 

This type of module consists of a membrane, which is placed between the feed spacer and product spacer and then the system is attached to both sides of a rigid plane or end plate (Fig. 4.3). The plates are made of different materials, e.g., porous fiberglass, solid plastic with grooved channels on the surface, reinforced porous paper, etc. The membrane unit is placed in a pressurized vessel. Feed water is forced to pass across the surface of the membrane for filtration. Permeates are collected in product manifold after passing through the membrane and brine solution is collected from porous media. However, this membrane module is not used in large scale applications because of the complexity and cost of operation. 

The third type of membrane module is the plate-and-frame assembly, which closely parallels that used in filtration. Such a module has a high capital cost but is resistant to fouling. Moreover, if the membrane in one of the plates fails, it can be individually replaced the entire module does not have to be discarded. This geometry is often used for ultrafiltration and has been used for pervaporation. I would expect its use for physical separations to be sustained but its use for diffusion-based separations to wane. 

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