Whether in steel production, cogeneration, energy-from-waste, cement plants, lime production, chemical manufacturing, foundries, asphalt, food processing, and many more industries, the reliable reduction of emissions is of paramount importance for worker health and safety, health of our environment & to achieving environmental compliance. While there are numerous factors to consider in operating baghouses in these industries, here are 6 maintenance tips for ensuring your baghouse – whether shaker, reverse-air or pule jet – is reliably and consistently achieving the needed dust removal for your production environment.
1. Establish an Inspection and Preventative Maintenance Program
First and foremost, a proper Baghouse Preventative Maintenance Plan will serve to maintain the efficiency and effectiveness of the air pollution control (APC) system.
A key component of this plan is monitoring the baghouse through a comprehensive set of performance-related inspections — daily, weekly, monthly, semi-annually, and annually. Establishing an inspection program – with key data points logged – will provide for a history of operation that can be used to effectively plan filter bag replacements, quickly identify small problems before they develop into major maintenance and operational issues, and serve as a reporting tool for your air permit requirements.
2. Regularly Change-out Filter Bags
High-quality filter bags are an absolutely critical component for the proper operation of your dust collector. To ensure that the dust collector is operating consistently at peak performance and efficiency, a regular inspection and preventative maintenance program is recommended, as outlined in Item #1 above. Even for the highest quality filter media, things can happen, as shown in the filter bag on the right.
Nuisance Dust Baghouses
There are 2 main reasons for changing out baghouse filter bags in nuisance dust baghouses:
- The dust being collected has blinded the bags by plugging the air passages in the fabric. This makes it difficult – if not impossible – for the dust to be collected and conveyed from the pickup points, as compared to use of clean, properly functioning filter media.
- The bags have developed holes or the dust has penetrated the fabric and is being discharged to the atmosphere.
Baghouses collecting finished products
For baghouses collecting finished products, in addition to bag blinding and/or holes having developed or dust penetrating the fabric, filter bags may be changed:
- To avoid cross contamination between lots of the same products
- When the production line is switched to a different product
- For sanitary reasons (e.g. to reduce the chance of contamination from bacteria, mold, or mildew).
3. Keep A Daily Log of Baghouse’s Differential Pressure (DP)
As part of a regular inspection and preventative maintenance program, keeping a log of baghouse differential pressure drop allows operators to assess if there are any deviations which may suggest a problem. The baghouse system’s differential pressure is actually one of the most important parameters in troubleshooting and diagnosing any operational problems with the baghouse system.
4. Ensure Effective Cleaning System Performance
For a filter bag to perform optimally, it must have a properly working cleaning system. Whether you have a Pulse Jet, Shaker, or Reverse Air system, it is critical that this system is operating properly to ensure that dust cake is being released from the filter bag.
Pulse Jet systems
- Ensuring the pulse air pressure is adequate. Based on filter media type, this will range from 50 psi – 90 psi in traditional low-volume, high pressure Pulse Jet systems.
- Ensuring the system is not over-cleaning. If a filter bag cleans too frequently, it may lead to premature bag failure.
- Cleaning air must be kept dry; any moisture or oil in the Pulse Jet cleaning system will damage your filter bags, leading to premature bag replacement.
Shaker Baghouse systems
- Ensuring drive belts for shaker logs are properly tensioned
- Ensuring shaft bearings are properly lubricated
Reverse Air systems
- Ensuring dampers properly isolate to promote effective bag cleaning
- Monitoring the reverse air fan for adequate cleaning energy (based on system design and media between (1”- 2” W.C.)
5. Inspect Hopper Evacuation/Discharge & Dust Removal System
For a baghouse to operate properly, it is essential that the hoppers are not used as storage and that the material is continuously evacuated. If material builds up in the hopper, it can lead to operational issues in the baghouse causing high differential pressure, re-entrainment of dust, and filter bag abrasion issues. Recommendations include:
- Daily inspection of the material handling system (e.g. airlock, screw, dump valve, etc.) that is evacuating dust from the hopper to ensure it is operating properly.
- Checking hopper levels to ensure there is no bridging of dust over the discharge valve or on the corner walls of the hopper.
6. Watch for Signs of Visible Emissions
When an air pollution control (APC) device such as a baghouse is operating properly, there won’t be any visible particulate emissions from the exhaust stack. Visible emissions can be caused by a broken or torn filter bag or a breached seal and such leaks must be located and rectified immediately. The exhaust from a baghouse should be inspected regularly, as part of your baghouse’s regular inspection and maintenance program to ensure full compliance with regulations and no excursions.
Need help with baghouse troubleshooting, mechanical repairs, baghouse change-outs, or developing and implementing a regular baghouse preventative maintenance program tailored to your industry and operating conditions?
Contact us at C.P. Environmental today!