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Following discussions with Beco Engineering in the USA, UK based KnitMesh Ltd has been appointed as sole licensee for the BECO Mist-Master and patented V-Mister demisting technology. European markets are being handled through KnitMesh in the UK and the American markets through the company’s Houston based operation, Enhanced Separation Technologies LLC.

Rebranded as KnitMesh VKR Enhanced™ mist eliminators, they provide high performance wherever liquid entrainment must be removed from a vertically flowing gas stream. "In terms of capacity, this technology has set the standard for wire mesh mist eliminator vapour and liquid handling," explained Paul Robinson, KnitMesh Sales Director. "Under normal conditions, it will handle up to 30% more gas flow than a standard mesh pad and our tests have shown that for design, a 20% increase is very reliable."

It employs the mechanism of a Von Karman Roll (VKR) around a bluff body (see fig. 1). A vortex develops in a low pressure zone downstream of the channel attached to the bottom of the mesh pad (see fig.2). Collected droplets are deposited in the trough where they form a flowing liquid stream. The high capacity channels shield the collected liquid and then drain it from two sides of the mist eliminator in steady streams to the tower periphery where gas velocity is so low that re-entrainment almost never occurs.

VKR Enhanced™ mist eliminators are the same height as a mesh pad with top and bottom grids therefore direct replacement is usually possible with no modifications to the vessel or column. And, since the collection troughs are relatively narrow, there are no problems with alignment between the hold-down hardware (such as tie wires or J-bolts) required to secure a pad to a support ring or support beams.
Typical Applications
Towers upgraded with latest generation packings and trays requiring mist eliminators to handle higher vapour flow rates and/or entrainment loads
Knock-out drum retrofits - saving the capital investment of a new vessel
High pressure applications with a close differential between vapour and liquid densities
Low surface tension systems where atomising by secondary droplet break up becomes prevalent
Installation below a high capacity vane where the mesh pad pre-conditions and coalesces fine droplets for vane capture, while the troughs direct collected liquid to the vessel periphery
High turndown situations - 50% more than conventional pads - where high droplet removal efficiency is required across a broad range of operating conditions.
Typical Results
Caustic chlorine plant: a saving of £140,000 per year in acid costs alone for a plant with a ten year history of chronic problems with caustic mist carryover from the 4th effect evaporator in a caustic chlorine plant. Following the installation of VKR Enhanced™ mist eliminators in the 2nd, 3rd and 4th effect evaporators, salt build-up was dramatically slowed down; caustic loss and acid consumption eliminated; a higher vacuum could be maintained; and water boil-off was faster.

Steel plant: the solution to an emissions problem (and cancellation of pending fines) created by a severe stack mud-mist carryover problem in a BOP (Basic Oxygen Process) scrubber system. A review showed that if the fan could be run dry, there would be no need for a downstream mist separator. Accordingly, an 8.5m diameter VKR Enhanced™ mist eliminator assembly was designed and installed in the outlet cone of the cooling tower upstream of the fan, above the cooling tower water sprays – along with a dedicated clean water face-spray system to continuously wash the VKR assembly.

Reader Enquiries
KNITMESH LIMITED, GREENFIELD, HOLYWELL, FLINTSHIRE, NORTH WALES, CH8 9DP, UK
Telephone
National: 01352 712058
International: +44 1352 712058
Fax
National: 01352 714909
International: +44 1352 714909
E-mail: sales@knitmesh.com     Website: www.knitmesh.com

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Issued on behalf of:
KnitMesh Limited
July 2005

For further information contact:

     Sue Mather LAMC
     Tel: +44 1342 833313   Fax: +44 1342 832864
     E-mail: suemather@btinternet.com