Ethanol Storage Best Practices


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This brief article covers the best practices for fuel ethanol storage and was published in April 2012 in Biofuels International Magazine.

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Ethanol Storage Best Practices

  1. 1. ethanol storage biofuels Green CMYK c76 m0 y100 k0 Pantone 362 c rgb r61 h164 b42 Blue CMYK c100 m56 y0 k0 Pantone 293 c rgb r12 g71 b157 Helvetica Black and Helvetica Ultra lightWhat considerations are necessary when storing ethanol?Good ethanolstorage practicesF or more than 30 years, of petrol corrosion inhibitor fuel ethanol has been in combination with caustic transported and stored contaminants sometimes found safely and effectively around in petrol. The exact cause is stillthe world. The two main areas being investigated. However, theof consideration for fuel ethanol industry trend among ethanolstorage are physical construction producers now is to minimiseand operation of the storage tank corrosion inhibitor/pHe bufferand preventing any contamination usage. Ethanol marketers shouldor unwanted changes to the be aware that as inhibitor treatfuel ethanol during the storage Without proper buffering additive, fuel ethanol pHe quickly falls below rates are lowered, there is anperiod. First, physical attributes specification increased potential for pHeof the storage tank that should and other corrosion problemsbe considered include ensuring byproducts of fermentation. ethanol as a blend component. prevented by the corrosionthe incorporation of compatible The pHe of fuel ethanol is a The Renewable Fuels inhibitor. Therefore as dosagematerials of construction and the measure of the acid strength Association in the US has gets closer to the minimumspecific tank operation, such as and is currently accepted as a recommended a procedure for required, accurate inhibitora high or low product draw and predictor of the fuel ethanol’s evaluation of corrosion inhibitor/ treat rate control becomes evergood tank recirculation capability. corrosion potential. Low pHe pHe buffer performance that more important. Since both Due to ethanol’s affinity for fuel ethanol has been linked to includes a requirement that over and under treatment ofwater, ‘open’ floating roof tanks higher potential for corrosion. proper buffering be maintained inhibitor can result in engine-storage tanks with the floating High pHe fuel ethanol may for up to 16 weeks. Fuel damage, fuel ethanol purchasersroof operating as the roof of the contribute to failure of plastic and ethanol buyers should check should insist that the type andtank that is also open to the other elastomeric parts found in for proper pHe on incoming amount of corrosion inhibitoratmosphere, should be avoided engine fuel systems. In the US, shipments. There is a written be included on the certificate ofin an effort to minimize the risk of fuel ethanol pHe is specified to be ASTM procedure to determine analysis for every shipment.water ingress. Secondly, many maintained between 6.5 and 9. pHe, ASTM D6423.advancements have been made to Fortunately, corrosion and Contaminantsconfirm the stability of fuel ethanol pHe can be easily managed by Every action has anduring storage over the past the application of the proper opposite reaction The corrosivity of any fueltwo decades. Monitoring of fuel amount of chemical fuel additive. including ethanol can beethanol characteristics, specifically The dominant type of additive The use of pHe buffering worsened by contaminants suchthe pHe, water content and used consists of a blend of corrosion inhibitors, especially as chlorides and sulphates.conductivity, during storage are organic acid corrosion inhibitor in excessive amounts, has been Though these contaminants arerecommended to confirm proper (commonly used in petrol and linked to engine problems such tightly controlled at the ethanolstorage conditions have been diesel fuel) along with an organic as intake valve deposits (IVDs). producer level, they can appearmaintained. A further discussion of amine that acts to neutralise the The problem IVDs may also be again in mid-level blends withthe properties to monitor follows. effects of the small amounts of caused or contributed to by petrol, which itself can be aPioneering research by General acids found in new ethanol and the use of excessive amounts source of chloride and sulfateMotors in the early 1990s created those acids that may be formedthe concept of pHe – the pH over time. Together, these twoof fuel ethanol. By definition, components manage corrosionpH is associated with water. issues and they are capable ofBut fuel ethanol is essentially buffering the ethanol pHe foranhydrous. GM’s research led long periods of time. This type ofto the discovery that ethanol additive is almost always used inthat contained large amounts North America, but is not normallyof dissolved CO2 (a natural used in South America. However,byproduct of fermentation) along much of the ethanol now beingwith small amounts of water will imported from South Americaform carbonic acid over time. In to Europe is being treated withaddition, fuel ethanol may contain corrosion inhibitor/pHe buffersmall amounts of acetic and by the major oil companieslactic acids that are unwanted and fuel marketers that use Intake valve depositssupplement biofuels international april 2012 7
  2. 2. biofuels headingen CMYK c76 m0 y100 k0tone 362 cr61 h164 b42e CMYK c100 m56 y0 k0tone 293 c r12 g71 b157vetica Black and Helvetica Ultra light Introducing EC5624A PLUS E85 fuel pump screen fouled with chloride salts NexGen Ethanol contamination. Sulphates can be and hydrous fuel ethanol. Corrosion Inhibitor particularly stealthy as they can This subject is an evolving unintentionally get into the fuel controversy, so ethanol blenders ethanol in the form of a sulphite, and marketers should stay Nalco has created a new formula to make our Ethanol and then oxidize to the more tuned for further developments Corrosion Inhibitor better, safer, easier to use and more troublesome sulphate form with as they change and are cost effective! oxygen exposure and time. Tests established internationally. that can detect this potential for As treat rates fall, it is more important than ever sulphate formation are readily The bigger picture available and have been adopted to manage dosage accurately. Nalco’s proprietary by most ethanol producers and Another parameter critical to fluorescent tracer makes treat rate management fuel marketers. Fuel ethanol engine performance, especially easy, fast and accurate. buyers should insist on specific engine startability, is Reid Vapor listing of chlorides, existing and Pressure (RVP), which is an Improved pHe boosting power potential sulphates in shipment indication of the volatility of the Better cold weather handling. certificates of analysis in order fuel. This is normally a parameter to ensure delivery of a quality that can be controlled only by the No more heated storage required! product to their fuel ethanol users. petrol/ethanol blender. However Excellent corrosion protection without risk of Sodium and silicon may it is important to note that petrol also end up in fuel ethanol and and ethanol, and other fuels intake valve deposits. ethanol blends in very small, but including diesel and biodiesel, Lower treat cost. potentially troublesome amounts. kerosene, jet fuel and heating oil Sodium is recognised and all have very different volatility Same regular, on-site service to help you maintain limited by the Brazilian ethanol characteristics. Extreme care ethanol quality and control inhibitor treat cost. specification, but it is not yet must always be taken at storage included in the North American facilities to minimise or prevent Discover more about EC5624A PLUS at specification. Silicon is not cross contamination of various regulated by either specification. fuels. Even small amounts of or call Phil Bureman Both of these contaminants can contamination can create large at 913-708-4969. be found, though only rarely, issues for the consumer. as a contaminant in both fuel Further, not all ethanol is used ethanol and petrol. In excessive as an E5 or an E10. An E15 blend amounts these contaminants is now being promoted for use can contribute to several engine in the US for engines of model problems. Both sodium and year 2001 and newer. Higher silicone are easy to test for if ethanol blends such as E85 and contamination is suspected. mid-level blends are already in limited use in North and South Conductivity America. As blend levels increase, the control of critical parameters Even though many fuel ethanol such as chloride, sulphate and regulations require that the fuel water contaminants, as well maintain a specific pHe, there as acidity, pHe, conductivity are some in the fuel ethanol, and corrosion inhibitor content petrol and automotive industry become even more critical. l that believe that ethanol pHe control may not be as important as conductivity management. For more information: This article was written by Phil Indeed ethanol conductivity is Bureman, senior industry technical limited in the Brazilian national consultant for biofuels at Nalco – An © 2012 Ecolab USA, Inc. Ecolab Company, specification for both anhydrous 0 april 2012 biofuels international supplement