Planning Ahead to Minimize Downtime
Many industrial facilities work hard to plan scheduled downtime to conduct maintenance as needed throughout the year. In some, however, production and operational requirements preclude periodic shutdowns. And for others, shutting down the process, even partially is not practical due to the amount of time required to restart production. For these reasons many facilities plan yearly maintenance outages where major repairs, installations and other tasks can be done all at once.
Following a comprehensive PM plan throughout the year is an effective way to minimize downtime. Planning is the key to efficient shutdown maintenance that accomplishes all required goals and helps reduce unplanned downtime during the rest of the year. Plants with dust collection systems preparing for their yearly shutdowns can begin planning for the following tasks now to achieve the best results come shutdown time.
Annual Preventative Dust Collector Maintenance Inspections
Experienced baghouse operators and maintenance personnel will testify that even a small investment of time, manpower or materials in preventative maintenance on dust collection system yields substantial returns.
Two of the highest priorities are to:
- check the cleaning system
- check the internal conditions of the collector and the filters
Start here where even minor problems can result in large drops in efficiency and high operating costs.
Check Cleaning System
Begin by inspecting the cleaning system components to ensure they are in good physical condition. On a pulse jet collector this includes the air compressor, air lines, air headers, pulse valves (including the diaphragms inside them), solenoids and the controller. Pay particular attention to the condition of the diaphragms inside the pulse valves. A good test is to have a technician listen for any signs of wear while the valves fire one by one (a good valve will have a crisp, clean sound when it fires. A worn-out valve will sound flat, like a horn, or much like a person having the wind knocked out of them). Additionally, make sure that the compressed air system is in good condition with oil/moisture traps ensuring a steady supply of clean and dry air for the air headers. On reverse air cleaning systems, check the reverse air fan and all dampers on the system. Also, make sure all inlet/outlet valves and poppet valves inside the unit are in good working condition and seated properly forming a tight seal. On shaker collectors check shaker motors and all other moving parts on the shaker mechanism to ensure they are in good working order.
By ensuring the cleaning system is in proper working order, dust collection systems will run more efficiently, thereby reducing emissions levels, lowering operating costs and increasing reliability (i.e. less downtime).
Inspect the Interior of the Collector Including the Filters
A year end shutdown is a good opportunity to inspect the interior of the baghouse modules or compartments including the filters. A technician should visually inspect the interior of the unit looking for any corrosion or other issues. Then conducting a dye leak can detect any leaking filters or holes in the structure or tubesheet that are too small to notice with the naked eye.
Many operators choose to change their filters on a fixed schedule to minimize downtime. This is tempting particularly in cases where the cost of downtime is quite high as in power plants. However, facilities that use broken bag detectors and baghouse control systems to monitor bag house performance can often rely on very early warnings or predictive alerts that a problem is developing - long before it reaches visual or reportable stages. This can lengthen filter life and substantially reduce the bag replacement budget of most facilities.
Nevertheless, an annual shutdown is an ideal time for a filter swap - whether simply according to a schedule, or based on instrument and monitoring observations.
Additionally, an important part of your dust collector maintenance planning is to source the needed parts well in advance, especially the filters and cages.
Finally, the annual shutdown is the perfect time to schedule any needed repairs to the units, whether large or small. Possible repairs include patching holes, removing corrosion, replacing discharge devices, etc. It can also include duct work additions or even the installation or upgrade of new bag leak detection systems, baghouse controls, or other monitoring equipment.
Conclusion
There are many preventative dust collector maintenance tasks that can be done throughout the year without having to shut down. In the long run, plants can be more effective at preventing downtime by following a comprehensive PM schedule throughout the year not only during annual shutdowns. However, certain major tasks like those described above are best performed when planned outages will minimize their impact.
