How to Keep Your Demister Pad Clean and Free from Common Failures

• Routine Maintenance

  Solids in a demister pad will eventually cause plugging, leading to excessive pressure drop and reduced performance. A cleaning regimen is a good idea and as with any piece of equipment, should be performed before accumulations or plugging severely affect demister pad performance. BOEGGER can design integral spray systems to continuously or intermittently wet the demister pad to minimize plugging issues.

  Spraying with cleaning liquids, boiling or soaking, or passing steam will help clean the demister pad. In choosing any of these options, be sure that they will not damage the mesh pad.

• Removing Fouled Demister Pad for Cleaning

  To achieve thorough cleaning, it is often helpful to remove the demister pad. Keeping a spare demister pad is ideal in such situations.

  Depending upon the degree of plugging (for instance coking or polymerization), it is often more economical to go ahead and replace the demister pad. Contact our BOEGGER separations specialist if you are experiencing continuous plugging problems, dislodged sections and short intervals between maintenance. Alternative design selections may extend your maintenance intervals. In severe fouling applications, you may consult with our separation specialist for more secure hold down options.

  Important Note:

  When your demister pad is removed, examine the cleaned mesh carefully to check if there are corrosion signs and if the wire diameter is reduced. When your demister pad is new, it is a good practice to measure the wire diameter using a micrometer. When you reach a 20% reduction in wire mass, replacing the demister pad should dramatically increase your efficiency.

• Troubleshooting

  Monitoring pressure drop across the demister pad may be the best option for determining acceptable operation. It is a good practice to record initial pressure drop at start-up under clean conditions for future observation.

  • If pressure drop increases more than an inch of water column above start-up conditions, some sort of plugging is most likely taking place. To rectify the situation, clean the mesh pad.
  • When pressure drop decreases across the demister pad, there are likely hole or voids in the pad or significantly reduced mesh density. Corrosion over time will reduce the mesh wire diameter, mesh density and in turn reduce pressure drop. Gaps in the mesh pad will cause channeling and a significant reduction in collection efficiency.

  In addition to pressure drop, monitor downstream process conditions, particularly after an upset. Increased liquid accumulation in downstream low points or vessels may indicate bypassing through the demister pad. Decreased pressure drop may indicate holes in the demister pad.

  BOEGGER demister pads are manufactured under strict conformance and quality control guidelines. They are designed to provide optimum performance in a variety of process applications. If you are experiencing chronic plugging problems or frequent maintenance, contact our BOEGGER separations specialist. Alternative mesh selections may extend your maintenance intervals.