In line with their quest for more sustainable processes, chemical companies are re-evaluating how they select dust collection and removal technologies. They are demanding improved energy efficiency, easier maintenance, greater product recovery and enhanced operator safety. More and more, they also are focusing on total cost of ownership (TCO) rather than initial price — an approach that equipment suppliers say has even more benefits than initially might be expected.
"Sustainability is a fact of life now and the most important aspects of it for us are reducing energy consumption and increasing product life. There are several layers to this. For example, when it comes to reducing energy consumption both design and filter media are important. Better media allow for lower smaller pressure drops. They also improve cleanability. If you need less cleaning, you use less compressed air, which is another energy saving for customers," explains John Dauber, vice president of sales U.S.A. and Canada for Camfil Farr Air Pollution Control, Jonesboro, Ark.
Sustainability also includes disposal costs incurred by spent filters, the benefits of providing clean air from a process to the environment and the overall carbon footprint of a plant.
"We try to save customers money over the life of a piece of equipment to give them the best value and the TCO is a very big issue for us, especially in the U.S.," Dauber adds.
The only accurate way to determine which filter is the most sustainable and economic choice is to carry out a TCO calculation. This requires information on three different cost elements: energy, consumables, and maintenance and disposal. Each category involves a number of factors.
For example, for energy, it's important to know how many days per year the collection system operates, the volume of air required, electricity's kWh price and how much each hour of no production costs. For consumables, filter costs are important but the analysis also must consider the number of cartridges within a dust collector and the shipping cost per filter. Maintenance and disposal costs must include factors such as labor and overhead rates per hour, cost of operating a variable frequency drive, and the time needed to change the filters.
IMPACT ON DESIGN
Dauber points out that TCO also can play an important role in the design of both new and revamped dust collection systems.
A project carried out by Camfil Farr at Amway's manufacturing plant in Ada, Mich., highlights this aspect. An aging filtration system there was struggling to cope with dust generated by a powdered detergent manufacturing process. In addition, the original 64 filters took two or three maintenance workers in protective clothing up to six hours to change. And this happened twice a year.
The company needed a solution that married high filtration efficiency with low maintenance and optimum worker safety.