KMS Advanced Nanofiltration (NF)
As advances in nanofiltration (NF) continue to stream into the global marketplace, Koch Membrane Systems continues to maintain its established role as the prime innovator.
KMS manufactures nanofiltration membranes in tubular, spiral and flat sheet membrane configurations.
Nanofiltration is a low to moderately high pressure (typically 50 - 450 psig) process in which monovalent ions will pass freely through the membrane but highly charged, multivalent salts and low molecular weight organics will be rejected to a much greater degree. Typical nanofiltration applications include water softening, desalination of dyestuffs, acid and caustic recovery and color removal.
Take a Closer Look at KMS Advanced Nanofiltration (NF)
Nanofiltration is a pressure driven process for separating larger size solutes from aqueous solutions by means of a semi-permeable membrane. This process is carried out by having a process solution flow along a membrane surface under pressure. Crossflow technology uses a high concentrate flow rate to enhance permeate passage and reduce membrane fouling. Retained solutes (such as dissolved salts) leave with the flowing process stream and do not accumulate on the membrane surface.
Pores have not been observed in nanofiltration membranes under any microscope, however, water can still pass through the membrane and multivalent salts and low molecular weight organics are rejected. It is difficult to predict the performance of nanofiltration membranes, especially if more than three solutes are present in the solution, since membrane rejection is influenced by the size, structure and charge of the components in solution. As a result, piloting is highly recommended for Nanofiltration applications, even if a detailed feed water analysis is available.
The KMS FLUID SYSTEMS® brand of membranes continues to be the premier reverse osmosis (RO) technology available worldwide. The latest innovation is the remarkable MegaMagnum® RO Element with an 18'' diameter and 60'' length.
KMS manufactures reverse osmosis membranes in the spiral membrane configuration.
Reverse osmosis membranes will reject dissolved and suspended materials including monovalent salts. Close to 99% of all dissolved and nearly all suspended material is rejected by the membrane.
For example, water can be softened with a nanofiltration membrane that rejects 85% of salt (sodium chloride) but 99% of the hardness ions (calcium and magnesium). The highest salt rejection rates (99.7% or higher), which can be provided by reverse osmosis membranes, are required for seawater desalination.
Reverse osmosis is a moderate to high pressure (80-1200 psig) driven process for separating larger size solutes from aqueous solutions by means of a semi-permeable membrane. This process is carried out by flowing a process solution along a membrane surface under pressure. Retained solutes (such as particulate matter and dissolved salts) leave with the flowing process stream and do not accumulate on the membrane surface. The amount of salt and other impurities is often referred to as TDS, or total dissolved solids. The higher the TDS, the more feed pressure required.
Membranes are made with various rejection rates for different applications. KMS produces membrane polymers to cover the full spectrum of reverse osmosis pressure ranges. One of these membrane types is the TFC® (thin-film-composite) family. TFC®-S (''S'' for softening) and TFC®-SR (''SR'' for selective rejection) elements are ideal for low TDS or softening type applications. For higher purity permeate, the ULP® (ultra-low pressure) membrane line offers high water flux and salt rejection in a 125 psi class membrane.
When salt rejection is paramount, the TFC®-HR (high rejection) elements offer 99.5% in standard form, or 99.7% in the Premium model. Typically used in brackish water applications with up to 2000-5000 mg/l TDS, they operate around 200 psi When the water is higher in TDS, the XR (extreme rejection) element comes into its own with 99.7% salt rejection and excellent silica and TOC (total organic carbon) removal too.
For seawater desalination, KMS offers the SS (single-stage) membrane in various sizes and configurations that allow optimum system design. In the Premium line, salt rejection is at least 99.75%! Many of the SS products are designed to run up to 1200 psi for high salinity/high recovery installations.
KMS other main product line is known as ROGA® elements (Reverse Osmosis General Atomic). All ROGA® elements are made with a CA (cellulose acetate) blend membrane, which is resistant to organic fouling due to its smooth surface and neutral charge. The CA membrane operates well on chlorinated feeds, making it ideal for wastewater plants or other applications where chlorine is present or desired to minimize bacterial activity.
KMS elements come in standard 40'' lengths, or in the new Magnum® series at 60'' long. The Magnum® series offers several benefits, including fewer interconnectors, o-rings, brine seals; higher active areas; greater productivity; and lower cost per installed gallon.
