Knitted wire mesh is used throughout the process industry in the separation of mist or small liquid droplets from a gas or vapour stream. Mesh pad design formulas are based on the principle of liquid particles colliding with the wire matrix and coalescing into larger droplets. Gravity will then cause the large droplets to fall through the mesh pad and collect in the vessel sump. "Dry" gas will exit through the downstream side of the wire mesh pad while the liquid is removed from the vessel through a dump valve. The use of petroMESH DEMISTER® mesh pads can be incorporated into both vertical and horizontal vessel configurations.
petroMESH has been a manufacturer of mesh pads since 2000 and produces several different styles of petroMESH DEMISTER® mesh pads in our Calgary facility. These styles are based on the density of the final mesh pad, the diameter of the wire used in the pad, and the crimp style that is used in the manufacturing process. A combination of styles can be used in a single petroMESH DEMISTER®.
While a few materials are certainly more common or prevalent, a wide range of materials can be used in the manufacture of both the petroMESH DEMISTER® and its supporting grids. petroMESH maintains an inventory of a variety of materials so that we may provide fast turnaround times for the replacement of existing mesh pads as well as rapid delivery of mesh pads for new installations. A petroMESH DEMISTER® can also be manufactured in virtually any size or shape and offers high separation efficiency at a low cost.
The following should be considered when determining which style of mesh is to be used:
- The flow rate and properties of the process gas.
- The flow rate and properties of the process liquid.
- The minimum micron size and efficiency of the liquid particles that are to be removed.
- The potential for clogging due to a viscous fluid.
Sizing and selecting a petroMESH DEMISTER® requires one to analyze four constraints:
- The vapour velocity system limit for gravity separation defined by the Sounders-Brown equation.
- The vapour velocity at which re-entrainment occurs.
- The degree of separation required.
- The pressure drop across the petroMESH DEMISTER® Additionally, one should consider the volume required for slug capacity as well as the pressure drop from the entrance and exit of the vessel.
Some of the typical applications for a petroMESH DEMISTER® include (but are not limited to) scrubbers, evaporators, absorbers, steam drums, refinery vacuum towers, sulphur plant coalesces, and refinery lube towers.