German Interindustry Study: Filter Blocking, Biofuels, Microbs conducted by DGMK (start 2008) presented by: Margret Schmidt Shell Global Solutions ISMOS-2 17.-19.6.2009
DGMK and biofuels projects DGMK - `technical research association of the German branches of mineral oil companies DGMK working groups: Fuels, Heating Oil, Supply&Distribution, Refineries Objective of the Fuels working group : Create and run technical investigation programmes about German fuels quality aspects Majority of current DGMK fuels projects are about biofuels, several about FAMEs in diesel fuel (OEM concerns) DGMK a mineral oil company association. However, for several biofuels projects DGMK has invited OEMs, FAME suppliers, additive companies for joined work 2
German interindustry study about filter blocking, biofuels, microbs Background Scattered problems with filter clogging at diesel dispensers since intro of B5 fuel (5% FAME, fatty acid methyl esters in diesel) on the German market from 2005 on Also scattered deposits at bottom and walls of B5 terminal tanks found During winter 2005/06 about 200 retail dispensers were affected, today still problems in the market. Not such problems before FAME (B5) introduction First DGMK spotchecks about filter blocking No relation to a specific region in Germany No impact of different technical configurations of dispensers, filters Some B5 tank terminals were microbial infected but not all further supplied retail stations 3
Appearance of deposits in a terminal tank Slimy deposits at wall and bottom of a B5 terminal tank Hole corrosion beneath slime deposits 3
Filter blocking Location of fuel filter at a retail dispenser Location of the main fuel filter in a dispenser Dispenser filter details 3
Appearance of blocked dispenser filters Majority of blockings appeared as typical dark slimy deposits Initial lab tests of the deposits showed always high microbial contamination Only a few blockings obtained as light fine deposits Analysis: FAME associated contaminants as sterolglucosides and others 4
DGMK approach to investigate the filter blocking phenomena Solubility of FAME/diesel blends Lab Microbial contamination of FAME/diesel blends (SGS Fresenius Germany) Literature t search about microbial contamination of fuels Market screening Filter blocking in Germany Identification of microorganism from market samples Water micro droplets in FAME/Diesel blends In-vitro lab investigation about fuel effects on microbial growth Target: Recommendations for fuels supply and handling practice to reduce and prevent microb growth in FAME/diesel fuels 5
Market screening Microbial filter blocking in Germany Targets Get an overview about the spread of microbial contamination along the German diesel fuel supply chain Verify suitable methods for determination of the microorganism Characterization of microbial material from samples Results 150 fuel and deposit samples from terminals and retail stations investigated Microbial methods: Total germination number of bacteria, fungi, mould cultivated on PlateCount-Agar or Sabouraud-Agar Measurement of metabolism activity, adenosine triphosphat (ATP) Microscopy 6
Market Screening Microbial filter blocking in Germany Results (cont ) Microbial contamination along the B5 supply chain supply chain terminal B5 tanks retail station B5 location sampling bottom phase fuel from middle tank bottom phase fuel from tank middle deposits at dispenser filters fuel out of dispensers microbial contaminated samples out of total >10 1 cfu/ml samples out of 25% 38% 41% 62% 95% 52% contaminated samples: concentration (bacteria, fungi, mould) cfu/ml 10 5-10 7 10 1-10 2 10 1-10 5 10 1-10 6 heavy biomass slight to deposits 10 1-10 6 7
Market Screening Microbial filter blocking in Germany Results (cont ): Visual impression of microb contamination along the supply chain: terminal tank bottom sediments terminal tank fuel samples deposit material from dispenser filter fungi hyphes and micro water droplets in the fuel phase,ca. 800x microbial biomass deposits at dispenser filter paper fungi hyphes in the diesel fuel phase (yellow), extend into water phase (dark), ca. 800x fungi hyphes between cellulosic dispenser filter material, ca. 800x 8
Identification of microorganism from market samples Results Both bacteria and fungi identified to comparable numbers But: fungi mycelia and hyphe meshwork main reason for filter blocking All identified fungi classified not or very unlikely to cause harm for humans TRBA 460 Examples for isolated and cultivated fungi species: Aspergillus terreus Thom Aspergillus terreus Thom 9
In-Vitro Lab Investigations about Fuel Effects on Microbial Growth Objective Do certain fuel parameters promote microbial contamination and growth? Investigation programme Preparation of 2 microbial inoculums: Defined fungi mix (10 numerous fungi, isolated and cultivated from deposit samples) Complex biomass (microb mix extracted from filter deposit samples) Inoculums were dry-freezed, then used for injection of 2 parallel fuel sets Fuel matrix: Diesel base fuel, 4 B5 (4 different FAMEs with diesel base fuel), 1 pure FAME Without / with extra added free water phase Microbial measurements: Biomass growth, ATP, DNA, RNA, proteins 6
In-Vitro lab investigations about fuel effects on microbial growth Results (Biomass growth exemplary) Defined fungi inoculum Complex biomass inoculum free water phase clear tendency to increased biomass growth for all fuels no correlation between FAME composition and contaminats (e.g.fame 2: higher P) and microbial growth Pure FAME with free water phase added showed rel. strongest microb growth free water phase no biomass growth compared to defined inoculum even tendency to reduced growth compared to without water phase results different to defined inoculum conflicting with expectations: complex biomass seen as more practice near then defined d inoculum 500 500 400 400 Biomass sezugewinn [%] 300 200 100 Biomass sezugewinn [%] 300 200 100 0 DK DK+FAME1 DK+FAME2 DK+FAME3 DK+FAME4 FAME1 DK DK+FAME1 DK+FAME2 DK+FAME3 DK+FAME4 FAME1 0 DK DK+FAME1 DK+FAME2 DK+FAME3 DK+FAME4 FAME1 DK DK+FAME1 DK+FAME2 DK+FAME3 DK+FAME4 FAME1-100 ohne H 2 O mit H 2 O mit Keimmix kontaminierte Ansätze -100 ohne H 2 O mit H 2 O mit komplexer Biomasse kontaminierte Ansätze 6
Preliminary conclusions from DGMK Project Filter Blocking Microbial contamination found as main reason for filter blocking In-vitro tests showed: Fuel samples with free water phase, injected with a defined fungi inoculum showed clear biomass growth Fuel samples injected with complex biomass inoculum obtained with contrasting effects: no effect of a free water phase These findings did not match expectations where just the complex biomass inoculum ( natural microb mixture) should represent real world microbial contamination better than a lab prepared defined fungi inoculum The contrasting results might be a caused by competition of bacteria vs. fungi metabolism in the complex biomass inoculum, impact of microb growth inhibition components or others 14
Outlook for completion work Study microb growth with focus to distinguish fungi and bacteria impact Fuels matrix with different FAME contents: B0, B7, B20, B100 Investigate t the impact of potential ti micro water droplets onmicrob growth, separate to water phase Summarize learnings from this DGMK study as handling recommendations for mineral oil companies practice to reduce impact factors for microbial growth in FAME/diesel fuels 14
Thank you for attention! 15