|
Petroleum and Tanks
|
Storage Tank Program - Converting to biofuel storage Biomass energy converted into liquid fuel is usually called “biofuel.” Two examples of motor biofuel are biodiesel and E-85. E-85 is covered under a separate fact sheet titled “Preparing Your Dispensing System For Ethanol Blended Motor Fuel” available at: http://commerce.wi.gov/ERpdf/bst/ProgramLetters_PL/ER-BST-PL-PreparingForEthanolBrochure.pdf. Biodiesel is gaining in popularity as a clean-burning biofuel. Biodiesel, as the name is commonly used in the motor fuel industry, is made from vegetable oils, animal fats and tallow, or recycled cooking oils. The term “Biodiesel” is frequently misused in a very broad application of motor fuels. Biodiesel by definition is B100 where the liquid is 100% refined oil from the vegetable or animal source. However, the term “biodiesel” is often misused to describe a blend with conventional diesel fuel where the term “biodiesel blend” should be used. Blends with conventional diesel fuels are referred to as B5, B10, etc where the “X” in the BX or BXX is the percent B100 in the total diesel/B100 blend. B2 is 98% diesel and 2% B100. Most Biodiesel (B100) is actually B99 because refiners or distributors receive a “blenders credit” if they add diesel fuel to the product and the typical range for the blenders credit is 0.5 to 1.0% making the product B99.5 or B99, both typically referred to as B99 or biodiesel. While biodiesel and biodiesel blends have significant desirable traits in relation to improving environmental air quality with lower emissions there are climate and solvent related traits that a user must be aware of. In relation to use, biodiesel and biodiesel blends are sensitive to cold weather and may require special antifreeze additives similar to petroleum-based diesel fuel. Bio blends also have a shorter shelf-life than conventional diesel with the lower BX/BXX level having the longer shelf-life. In relation to storage, biodiesel acts like a detergent additive by loosening and dissolving sediments in storage tanks that previously stored conventional diesel. The biodiesel solvent characteristics may cause elastomers, plastics, rubber and other non metal components to soften, fail, oxidize or degrade in older vehicles and fueling equipment. This problem occurs less with biodiesel blends, but for blends of 20 percent and higher it is recommended that natural rubber components be replaced with a more compatible material. Natural rubber is usually found in pre-1994 vehicles. Biodiesel may also require retrofitting of metal components, such as brass, bronze, copper, etc., in refueling equipment such as pumps and meters. The reduced sulfur content now mandated of conventional diesel has resulted in fuel lubricity concerns. A 2% blend of biodiesel is sometimes added to diesel fuel (commonly called B2) to enhance fuel lubricity in an engine. A 20% blend of biodiesel (commonly called B20) is added to diesel fuel to reduce engine exhaust emissions. Mixing biodiesel at a 20% rate provides most of the emission reduction benefits associated with biodiesel with only a slight increase in cost over conventional fossil diesel. Converting to Biodiesel Before committing a lot of time and money to converting to biodiesel you should review the U.S. Department of Energy Biodiesel Handling and Use Guidelines to gain more knowledge of the product and equipment requirements. Having more comprehensive knowledge will be to your benefit in determining your source of product (quality control) and in working with contractors and overall decision making. The guide can be accessed on the Internet at the following link: http://www.nrel.gov/vehiclesandfuels/npbf/pdfs/40555.pdf Cold Weather Management Wisconsin winters can get very cold and unlike gasoline, both petroleum diesel and biodiesel can gel at cold temperatures. Biodiesel can clog filters or eventually become too thick to pump from the fuel tank to the engine. B99 gels at a higher temperature than conventional diesel fuel. Most B99 begins to thicken (cloud) at around 35°F. To prevent cold flow issues, some users switch from B99 to a blend of B50 or lower in cold weather (below 35°F). Other options for using B99 in cold weather include keeping vehicles in a heated garage, using fuel system heaters, or using winterized biodiesel (biodiesel with cold flow additives). Converting to blends up to B20 Biodiesel has solvent properties that can dissolve the accumulated sediments in vehicle fuel tanks or bulk storage tanks when the fuel is first introduced. B20, being a 20% blend, has a milder effect than pure biodiesel (B100). While many references claim it is not necessary to clean storage tanks before switching to B20, we believe it is a good practice. At a minimum you need to check tanks for water, algae, and other contaminants prior to using the bio blended motor fuel. Even with tank cleaning occasionally a vehicle fuel filter or dispensing filter will become plugged as the biodiesel loosens build-up from previous fuels. Filter clogging that may occur with B20 typically goes away after the first few tanks of fuel. The dispenser should have a one micron fuel filter installed. Converting to blends from B20 up to B100 Higher BXX blends are likely to dissolve the accumulated sediments in diesel storage and engine fuel tanks, which can lead to plugged fuel and dispensing filters. Due to the lower dilution level previously successful use of B20 does not mean that tanks are without sediment. Before using or storing these higher blends clean the fuel dispensing system and fuel tanks where sediments or deposits may be present. Plan and budget for the time and expense of cleaning fuel systems in advance, or for increased fuel filter changes afterwards. Be sure to monitor fuel filters and change them as needed until the sediment build-up is eliminated. Biodiesel Storage for B99 Many petroleum companies do not recommend storing biodiesel blends for more than six months. Current industry recommendations are for biodiesel to be used within six months or reanalyzed to ensure that fuel continues to meet ASTM D 6751 specifications. Tank Materials : Most tanks designed to store diesel fuel will store blends of B20 and above with no problem. However, B99 requires some additional considerations. Acceptable storage tank materials include aluminum, steel, fluorinated polyethylene, fluorinated polypropylene, Teflon, and most fiberglass. Moisture : Moisture is detrimental when combined with any biodiesel product and can ultimately affect both equipment performance and equipment maintenance. Keeping tanks moisture free also reduces bacteria and algae growth, or “bugs” as they are commonly referred. The residue from the bugs is very acidic and has significant potential to corrode tank bottoms. Periodic testing is recommended to ensure that microorganisms are not present. Temperature : B99 should be stored at or above 40° F. B99 can be stored in underground tanks without additional considerations as temperatures in underground storage are normally above 45° F. Above-ground fuel systems should be protected with insulation, heating systems, or other measures if temperatures regularly fall below the cloud point of the fuel. Make sure that fuel pumps, lines, and dispensers are protected from cold and wind chill with properly approved heating and/or insulating equipment. Converting existing tanks
Comm
10 is the Wisconsin storage tank code
and can
be accessed at:
Converting
an existing tank follows the points that are discussed above. A form must be completed for blends above B5
prior to performing the conversion and submitted to the department:
Installing a new tank
The
design and site plan must be submitted to the department prior to
installing a
new tank system. The plan submittal
application can be accessed at: The installation must be supervised by a Commerce certified installer (Comm 5). List of Wisconsin certified tank installers via the Commerce “Search for Tank Contractor Company by Tank Specialty” application (middle search box): http://apps.commerce.wi.gov/SB_Credential/SB_CredentialApp All tanks must be registered: AST – http://commerce.wi.gov/ERpdf/bst/Forms_FM/ER-BST-FM-8731-AstReg.pdf UST - http://commerce.wi.gov/ERpdf/bst/Forms_FM/ER-BST-FM-7437-UstReg.pdf
Questions
regarding tank system regulations can be addressed to the individuals
in the
following districts: |
|