Membrane Filtration & Separation Technology.
Cross-Flow (Tangential Flow) Filtration Vs VSEP
Not all membrane-based filtration is created equal.
As you can see from the above diagrams, traditional membrane filtration – even with high velocity fluid flows – can lead to plugged pores, fouling (boundary layer build-up) and unacceptably low permeate rates.
The VSEP system on the other hand uses a gentle cross-flow combined with a high sheer cleaning action and vibrating membrane to dissipate solids off the surface and ensure the pores are always open to deliver a high rate of permeate.
The Secret of our Patented Resonating Drive System
The key to VSEP’s efficiency is the unique agitator action of its resonating Drive System combined with the ingenious eccentric weight.
The disk stack is oscillated above a torsion spring that moves the stack back and forth 2.22 centimetres.
This motion is similar to the agitator of a washing machine but obviously occurs at a speed faster than the human eye can perceive.
This oscillation produces a shear at the membrane surface of about 150,000 inverse seconds.
Equivalent to over 200 G’s of force, this is approximately ten times the shear rate of the best conventional cross-flow systems currently available.
More importantly, the shear in a VSEP System is focused at the membrane surface where it is cost effective and most useful in preventing fouling, while the bulk fluid between the membrane disks moves very little.
How the VSEP Filtration System Operates
At the commencement of operation, the VSEP system is fed with a slurry and the concentrate valve is closed.
Permeate is produced and suspended solids in the feed are collected inside the VSEP filter pack.
After a programmed time interval, valve one is opened to release the accumulated concentrated solids. The valve is then closed to allow the concentration of additional feed material. This cycle repeats indefinitely.
Membrane selection is the single most important factor that affects the quality of the separation. Other important factors that affect the system’s performance are temperature, pressure, vibration amplitude, and residence time. All of these elements are optimized during testing and entered into the programmable logic controller (PLC) which controls the system.
The operating pressure is created by the feed pump. VSEP machines can routinely operate at pressures as high as 1,000 psig (68.95 BAR). While higher pressures often produce increased permeate flow rates, they also use more energy. Therefore, an operating pressure is used that optimizes the balance between flow rates and energy consumption.
In most cases, the filtration rate can be further improved by increasing the operating temperature. The temperature limit on a standard VSEP system is 79°C, significantly higher than competitive membrane technology. Even higher temperature constructions are also available.
The vibration amplitude and corresponding shear rate can also be varied which directly affects filtration rates. Shearing is produced by the torsion oscillation of the filter stack. Typically the stack oscillates with an amplitude of 1.9 to 3.2 cm peak to peak displacement at the rim of the stack. The oscillation frequency is approximately 53 Hz and produces a shear intensity of about 150,000 inverse seconds.
Feed residence time is set by the frequency of the opening and closing of the exit valve (valve one). The solids level in the feed increases as the feed material remains in the machine. Occasionally, a cleaner is added to the membrane stack and continued oscillation helps clean the membrane in minutes. This process can be automated and only consumes around 189 litres of cleaning solution thus reducing cleaner disposal problems inherent with other membrane systems.
Membranes for every application.
VSEP buys top quality polymeric membranes from leading manufacturers and modifies them accordingly. There are currently four membranes that can be used in a VSEP. They are:
Porous Microfiltration (MF) membranes are good for removing large suspended solids and are especially useful in dewatering slurries.
Ultrafiltration (UF) holds back 100% of the suspended solids, including proteins, pyrogens, bacteria and colloids.
Nanofiltration (NF) remove organics & hardness. They are used in wastewater treatment to remove or reduce BOD/ COD, and as pre-treatment to a RO VSEP or spiral RO system.
Reverse Osmosis (RO), the “tightest” of all membranes, are used to remove dissolved metals and provide high purity water. They are designed to hold back sodium chloride (NaCl). Seawater desalination membranes are typically rated to reject 99.5% NaCl.
In VSEP systems, RO membranes are used to remove organics, trace oil, and trace metals in a single unit operation, without widespread fouling.
Syngineering offer you a complete suite of VSEP separation systems as well as spiral-wound reverse osmosis systems, performance chemicals, engineering, and field services.
Available in three sizes the original Series i remains a very popular product. All Series i systems are available fully automated and require very limited operator interaction.
The smallest of the VSEP line, the i18 is perfectly suited for smaller flows. The available membrane area in the i18 filter pack ranges from 14m2 to 27m2.
A perfect size for high solids applications and moderate flow rates, the i36 was the original workhorse of the Series i family. The available membrane area in the i36 filter pack ranges from 42m2 to 56m2.
The most widely used VSEP with up to 130m2 of membrane area in each filter pack, the i84 is the ideal module size to process larger flow rates. Many i84 system configurations are available – including use in tandem – to fit your needs.
The P50 can process a few litres per minute , and is perfect for applications such as precious metals recovery and other high value/low flow applications.
The “Lab & Pilot” (LP) system can be configured for use in lab or pilot mode, making it ideal for data gathering, feasibility studies and application development.
A scaled down, low-pressure version of the LP, the lighter, quieter Series B is designed primarily for demos.
Spiral RO Systems
Can be supplied either as standalone units or in combination with VSEP units – either before or after the VSEP system. Applications include processing coal seam gas or field water and drinking water or potable water production.
These membrane performance chemicals together with membrane cleaners, flux enhancers and anti-scalants help keep your VSEP system operating at its peak.