Archive for December, 2018


FUEL & FUEL SYSTEM MICROBIOLOGY PART 25 – AND NOW FOR SOMETHING COMPLETELY DIFFERENT

In my October What’s New blog post, I highlighted several of my primary takeaways from PEI’s 2018 convention. In this post, I’ll focus on one new commercial offering. If it works as promoted, this system can be a game changer for contamination control in underground storage tanks (UST). At the convention Veeder-Root showed a model of their new CleanDiesel In-Sump Fuel Conditioning System (ISFC). I haven’t seen any field data from retail or commercial sites using this system, so I’m not able to endorse the system (I asked Veeder-Root for permission to discuss their system but have no financial interest in their company or this filtration system). Still, I think it is an exciting innovation with great potential.

The Issue

As I’ve discussed in previous articles – including my paraphrasing of Rebbeca Moore’s summary of contamination typically present in a 7,500-gal fuel delivery (i.e., 1 cup (∼0.25 L) of dirt + 1 to 2 gallons (3.8 L to 5.6 L) of water + up to 325 gallons of FAME (B5 ULSD is now included in ASTM Specification D975 Diesel Fuel Oils) + 1 gallon of glycerin + 5 to 40 gallons of additives). These concentrations of dirt and water are traces (<9 ppm by volume dirt and <200 ppm by volume water) on a per delivery basis, but they add up over time. For example, a UST receiving weekly ULSD deliveries will also received 52 gal to 104 gal (∼200 L to 400 L) of water per year. Even if only 10 % of the delivered water settles out, that’s plenty of water to provide an excellent niche in which microbes can facilitate microbiologically influenced corrosion – MIC (see
Fuel Microbiology Part 19 from April 2018
). Amongst fuel industry folks who specialize in product quality control, the consensus is to minimize water accumulation in UST. As I discussed in Part 19, keeping tanks water-free is easier said than done.

Veeder-Root’s CleanDiesel In-Sump Fuel Conditioning System

I’ve copied figure 1 from Veeder-Root’s ISFC flier and added a few component labels. According to Veeder-Root, the ISFC uses recirculated fuel to create turbulence in fluid at the bottom of the UST. This turbulence causes water, sludge and sediment to be suspended into the product. These resuspended contaminants are then pulled through a perforated inlet component and subsequently flow through a particulate filter and water separator before the polished fuel is recirculated back into the tank. In theory, the turbulence and contaminant capture zones are both sufficient to prevent contaminants from accumulating anywhere along the UST’s bottom.

Potential Impact

When I saw the ISFC demonstration at Veeder-Root’s PEI Convention booth, I thought that the design was simple, elegant, and promising. Its design includes modes that trigger polishing when water is detected by the automatic tank gauge or by a timer (system activated for some number of minutes per scheduled interval). My principal concerns were about the dimensions of the turbulent zone and the polishing system’s contaminant capture efficiency. If only a fraction of the UST bottom is resuspended, water, sludge, and sediment will still accumulate elsewhere along the UST bottom. Any particulate or water contamination that’s resuspended will begin to settle immediately after the recirculation cycle ends. This could create a mechanism for redistributing – rather than removing – contaminants. Another concern is system maintenance. Veeder-Root has estimates of expected filter life. Additionally, they have sensors to measure pressure drops across the filtration unit and water levels in the water separator. Still I can’t help but wonder if sites using the ISFC will quickly grow tired of either having in-house staff or contractors keep up with system maintenance (i.e., changing filters and removing water). My concern here is based on my experience with several petroleum companies who had installed filtration systems between their terminal tanks and racks, only to later remove them because of the filter element replacement costs.

Bottom Line

I think that the ISFC has great potential – even if it’s less than 100 % effective. It directly addresses many of the current challenges related to keeping water and particulates from accumulating on the bottom of UST. I hope that within the next year or two, Veeder-Root will be able to publish a case study or two reporting the impact of ISFC installation and operation at retail and commercial sites. I encourage anyone interested in learning more about the ISFC to contact Diane Sinosky, Veeder-Root’s Global Product Manager, ATG. Diane can be reached at dsinosky@veeder.com. Of course, I always welcome your fuel & fuel system comments and questions at fredP@biodeterioration-control.com.

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