Operational Cost

Operational Cost Comparison

A critical factor when evaluating bulk fuel filtration systems is the technology used for removal of free and emulsified water. Correctly designed bulk filtration systems should include pleated media filtration with coalescing and separation filters that allow for separation of free and emulsified water while maintaining high flow capacity. Water absorption technology, e.g. “spin-on” type canisters, often used by competitors’ systems, is not suited for bulk filtration and is most appropriately used in final fueling applications (e.g., on-site fueling, retail gas stations and aircraft fueling). One of the concerns in the use of absorption filters is the variability in flow rates. As a water absorption filter becomes saturated, the flow rate through that filter decreases dramatically, therefore the flow is not ratable or consistent. Compounding the situation is another design concern used in competitors’ systems and that is a time based cycle, with an assumed flow rate (no flow meter) vs. volume based with an accurately measured (flow metered) filtration cycle. Because the actual flow rate with absorption filters declines as a filter absorbs water, an assumed flow rate is an inaccurate measurement of the actual fuel filtered. The result is inadequate filtration of the fuel in the storage tank, compromising the intended design purpose of the filtration system. ESI systems are accurately measured using flow meters and lead to substantial savings.

Another consideration associated with the use of water absorbing filters is their significantly higher operational cost. The spin-on filters often used on competitors’ systems become fully saturated and need replacement after absorbing approximately ½ gallon of water. The result is unnecessary labor and materials cost, because the spin-on filter elements are a highly consumable part in this application. The operational cost impact when using water absorbing filters in a bulk filtration system is significant. For example, 0.25% water is a small percentage, but in two 50,000-gallon storage tanks this equates to 125 gallons of water per tank for a total of 250 gallons. To remove 250 gallons of water with absorption filters, which absorb ¼ gallon each, would require approximately 500 filter set changes (2 per set) at $100 per change for a total of $50,000. It is not uncommon for this amount of water to be removed from two 50,000 gallon underground storage tanks on a yearly basis. In addition to the high cost, this approach also includes a significant environmental impact associated with the disposal of 1,000 used filter elements.

By comparison, the coalescing and separation filters separate water into the filter vessel’s sump; a process that does not consume filter elements. When the volume of separated water in the sump reaches approximately four gallons, an automatic integrated process drains the water from the sump into a connected 55-gallon drum. The system monitors the water level in the drum and an alarm indicates when the drum is full. The reusable drum is designed to be pumped empty by an appropriate waste disposal company, e.g. Safety-Kleen, and then put back into continued service.

The following cost analysis is a representation that compares these two approaches to water removal from the fuel storage tank. This chart assumes 250 gallons of water is filtered out per year (0.25 % of tank capacity).

Operational Cost Comparison – ESI’s Volume-Based Water Separation Technology vs. Absorption Technology for Water Removal