Guest Editorial - Total cost of ownership analysis helps determine ideal dust and fume collection system
Total cost of ownership analysis helps determine ideal dust and fume collection system
May 2019 - Dust and fume collection systems help prevent respiratory problems and keep facilities in compliance with air-quality requirements. OSHA requires that metal dust particles and welding fumes be captured and contained if they contain toxic or combustible materials, like iron, lead oxide, nickel, zinc oxide, hexavalent chromium and manganese. These systems also protect the cranes, robots, welders and other expensive, sensitive equipment used in fabricating plants.
When designing a new or refurbished dust collection system, conducting a total cost of ownership (TCO) analysis can ensure that you purchase the best system for your application. TCO helps compare the real operations with different filters and evaluate the impact of energy-saving electrical components. TCO looks at four key operations factors: energy, consumables, maintenance and disposal.
Energy: When calculating TCO, a primary consideration is the amount of energy required to operate the dust collector, including electrical costs, compressed air usage and CO2 emissions. The system’s fan or blower uses the most energy because that is what moves air through the system. Differential pressure losses are directly proportional to the amount of air moved which, in turn, is directly proportional to the cost of energy used.
If your dust collector can recirculate the filtered air back into the facility, you can save on energy costs because you no longer have to bring in and condition (heat or cool) make-up air from outside. Recirculation also helps to keep your facility pressure balanced.
Consumables: Consumable components of a dust collector are the items that are replaced periodically throughout the life of the equipment. The priciest consumables to replace are cartridge filters.
Maintenance: Maintenance includes the time it takes to service the equipment, including the cost of having replacement filters delivered to the facility and the cost of carrying an inventory of replacement filters, the cost of labor required for maintenance personnel to change filters, and the downtime costs due to stopping operation of the collector for a filter change.
Disposal: You must also consider the cost of disposing of the consumables. It can be very costly to dispose of filters laden with process dust, especially if it is hazardous.
Key cost component
Dust collector operating costs are largely dependent on filter service life. Your filter change-out schedule will determine how many filters you can expect to buy, transport, store and dispose of. It will also give you a solid idea as to the costs of labor and downtime associated with filter replacement.
Filters use more energy in the early stages of service life. This is because new, clean filters have the lowest differential pressure, so more air blows through the system than required, wasting energy. As filters become loaded with dust, static pressure increases, moving less air.
Using a variable frequency drive (VFD) that controls fan speed will help to maintain a constant airflow. The VFD decreases speed when filters are new and speeds up the fan when filters become loaded, minimizing energy consumption.
Having dust samples professionally tested is the only way to be certain that your filters have a high enough efficiency rating to meet regulatory permissible exposure limits for your operation and type of pollutants. To choose the correct filter size and media, you need to know the size and shape of the dust particles, whether the dust is combustible, and if it is dry or sticky.
Informed decision
Charting the data will help you make a more informed decision. For example, it helps to compare two standard filters. Filter A, at a unit cost of $90, is a conventional dimple-pleat style cartridge filter. Filter B, at a unit cost of $120, is an open-pleat style cartridge filter designed for extended service life and lower pressure drop operation.
Dust collectors that are designed based on facts rather than guesswork perform as required with lower energy and operating expenses. Your equipment supplier can help you gather the data needed to make the most cost-efficient choice. Charting TCO for various filter types enables you to compare the real costs of operating a dust collector so that you can make the best choice to keep your workers safe and your facility in compliance. FFJ
Matt Caulfield is the national sales director–APC Americas for Camfil Air Pollution Control, where he’s worked for 12 years. With 19 years in the dust collection business, Matt has sized and installed systems into numerous dust applications for a range of industries.
