GENERATOR DAMAGE
Figure 4. UST system with steel tank with severe metal corrosion (43-MD-ST: [installed 1992; age of filter unknown). From left: fill pipe opening; STP shaft; tank top showing manway; ATG probe and STP shaft.3
formation. Note the J1488 standard is in the process of being updated in 2023. The SAE J1488 test procedure5
focuses
on the prevention of damage to diesel engines. From the Forward: “Water in fuels is one of the major causes of diesel engine maintenance problems. The effects of water in fuel are characterised by corrosion of fuel system parts, plugging of filters and orifices and, in some cases, failure of fuel injection equipment. Water in fuel often dissolves sulfur compounds, becomes acidic, and enhances corrosion in fuel injection systems as well as in the engine itself. The presence of water also encourages microbiological growth, which generates orifice and filter restricting sludge. Further, due to displacement of fuel lubrication in close tolerance injector parts, and rapid expansion of heated water at the fuel injector tip, galling, and more serious failure may also occur.”
J1488 Test Procedure The J1488 test procedure has two phases: 2500 ppm water is added to fuel samples in each test phase and is mixed using a 3500 rpm pump to emulate a fuel loading pump. The 1st phase uses pure diesel with no
surfactants, this phase tests for free water filtration. The 2nd phase a standard surfactant monoolein is added to emulate a B20 blend, this phase tests Micelle filtration.
J1488 Test Results In the 1st phase of filtration of free water, all filters are approximately 100 per cent efficient; all water is removed. In the 2nd phase of filtration of Micelle:
traditional filters cannot contact the water encapsulated in Micelles, and filters have low efficiency at removing Micelles. Only two filter manufacturers have
released their J1488 test results showing high efficiency in removing Micelles. These filters can keep water content below the 200 ppm water warranty level required by emergency generator manufacturers. This means a minimum 92 per cent filtration efficiency: 2500 ppm water added * (1 – 0.92 per cent ) = 200 ppm water remaining.
90
Microbes produce acids, which corrodes critical backup generator and storage tank components. Traditional filtration is not very efficient
in removing Micelles, so Micelles bypass the filters and scour injector components, greatly increasing maintenance costs and risk of backup generator failure. Two factors that can provide a
Figure 5. The testing organisation provides a
J1488 test certification report to the filtration company detailing the test results. Ask for this test report when considering a fuel filter.
Summary There are, then, two damage vectors: corrosion and Micelles. Surfactants are added to all liquid fuels, such as diesel (biodiesel) and gasoline (ethanol). Surfactants encase water droplets to form Micelles, which settle to the tank bottom, forming a layer that is very conducive to microbial growth.
prediction as to the amount of corrosion and Micelle damage caused to a storage tank and emergency backup engine: the length of time the fuel is stored (1 year, 5 years, 10 years, etc), and the concentration of the surfactant used (B4, B5, B10, B20, etc). Biodiesel is mandated in most jurisdictions; United States at B5, EU at B5 - B7.5, Canada at B4. B20 diesel will show major issues after
one year of storage, B4 after 10 years, and B5 after eight years.
Micelle and corrosion control SAE J1488 is the only filtration standard designed to test the efficiency of filters in removing Micelles. The filters on fuel polishing systems and backup generators should be tested against SAE J1488 and have a filtration efficiency of at least 92 per cent in order to keep water in Micelles below 200 ppm, the warranty standard for most backup generators.
References 1 Passman FJ. CRC Project DP-07-16-01. Identification of potential parameters causing corrosion of metallic components in diesel fuel underground storage tanks. p102. 2021.
2 Battelle Report. Corrosion in systems storing and dispensing ultra-low sulfur diesel (ULSD), hypotheses investigation. p3. 2012.
3 U.S. Environmental Protection Agency Office of Underground Storage Tanks. Investigation of corrosion-influencing factors in underground storage tanks with diesel service. p29. 2016.
4 Stamps BW, Bojanowski CL, Drake CA et al. In situ linkage of fungal and bacterial proliferation to microbiologically influenced corrosion. pp2, 10. 2020.
Injector orifice/needle tips micron size
Figure 6.
5 SAE International (2010) Emulsified water/fuel separation test procedure [
https://www.sae.org/standards/content/ j1488_201010].
IFHE DIGEST 2024
IFHE
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60 |
Page 61 |
Page 62 |
Page 63 |
Page 64 |
Page 65 |
Page 66 |
Page 67 |
Page 68 |
Page 69 |
Page 70 |
Page 71 |
Page 72 |
Page 73 |
Page 74 |
Page 75 |
Page 76 |
Page 77 |
Page 78 |
Page 79 |
Page 80 |
Page 81 |
Page 82 |
Page 83 |
Page 84 |
Page 85 |
Page 86 |
Page 87 |
Page 88 |
Page 89 |
Page 90 |
Page 91 |
Page 92 |
Page 93 |
Page 94 |
Page 95 |
Page 96 |
Page 97 |
Page 98
