SPURRED by federal and state tax incentives, demand for biodiesel is on the rise. Storage terminal operators would do well to get prepared.
This was the message from Paul Nazzaro, Advanced Fuel Solutions Inc, at the Independent Liquid Terminals Association's 25th annual International Operating Conference June 6-8 in Houston, Texas. He provided a detailed update on the status of biodiesel.
One of the strongest government mandates for biodiesel took effect January 1. The federal JOBS (Jumpstart Our Business Strength) Act lasts two years and provides a tax incentive of one cent per percentage of biodiesel per gallon of fuel made from virgin vegetable oils and animal fats and a half-cent per percentage for biodiesel made from other feedstocks.
Biodiesel demand could get an even bigger push at the federal level if the Senate energy bill passed in June becomes law. The bill would extend the current biodiesel tax incentives and would mandate that eight billion gallons of ethanol and biodiesel be used in transportation fuels by 2010.
Even without the latest Senate initiative, biodiesel consumption is projected to reach 40 million gallons this year. Nationwide use in 2004 topped 20 million gallons. Biodiesel is used both as a vehicle fuel and for heating applications.
Attractive fuel
Nazzaro stressed that biodiesel is an attractive alternative fuel for a number of reasons. Most importantly, engine emissions are lower with biodiesel. It is virtually sulfur free, has no aromatics, is biodegradable and non-toxic, and has high lubricity and a cetane rating over 50.
Biodiesel is relatively easy to handle at the terminal level, according to Nazzaro. However, it does act as a solvent, and blends greater than 20% can clean out sediments and accumulated material in vehicle fuel systems, storage tanks, and piping. Filters may have to be replaced frequently until the system is fully purged.
Biodiesel and biodiesel blends can form high sediment levels when in contact with certain metals: brass, bronze, copper, lead, tin, and zinc. The fuel is compatible with mild and stainless steel and aluminum.
At higher concentrations — especially B100 — the fuel can adversely affect some elastomers, such as natural and nitrile rubbers. At blends of B20 or below, there is little or no impact on those materials. Elastomers such as Viton and Teflon are unaffected.
Fuel degradation
Biodiesel can be degraded in a number of ways, including air, water, and the fuel itself. Air entering storage tanks through vent pipes can contain high levels of moisture, which increases oxidation in the fuel. The best solution is to avoid longterm storage of biodiesel in a partially full tank. Stabilizers are a must to protect the fuel. Nazzaro also recommended the use of desiccant dryers and reliable water management protocols.
“Lack of good housekeeping practices absolutely will increase operational headaches,” Nazzaro said. “It's important to test for water in a storage tank, and the system for removing water must be operational. Tanks must be gauged before and after each fuel delivery as part of a regular program to verify fuel quality.”
Free water in a storage tank can be especially damaging to biodiesel. Free water accelerates corrosion and fuel degradation. It also provides a fertile environment for microbial growth.
Fuel stored for long periods can degrade forming insoluable materials that will plug fuel filters on vehicles, foul engine injectors, and form combustion system deposits that promote corrosion. Other contaminants — such as sand and dirt — can arrive when new batches of biodiesel are delivered to a terminal.
Cold impact
Cold weather poses some additional challenges for storage terminals handling biodiesel. Wax formation and gelling occur at higher temperatures in biodiesel, and these factors must be taken into account by terminal operators.
“Many of the same precautions need to be taken with biodiesel and biodiesel blends that terminals currently are taking with petroleum-based diesel to ensure trouble-free winter operations,” Nazzaro said. “Storage tanks, injections systems, and associated hardware and pipes will require heat.
“At the fuel user level, traditional cold weather diesel solutions — kerosene blending, engine block and fuel filter heaters, and in-door garaging of vehicles — work just as well with biodiesel. Cold flow additives should be mixed in while the fuel temperature is above cloud point.”
Most biodiesel will be blended with petroleum diesel before being shipped to customers, and the blending probably will be done at storage terminals. Nazzaro pointed out that biodiesel is slightly heavier than petroleum-based diesel (specific gravity of 0.88 versus 0.85).
Ideally, biodiesel should be added on top of petroleum-based diesel in a storage tank, and the fuels should be agitated or mixed in the tank. Biodiesel blends should be stored at temperatures that are at least 10 degrees above the cloud point. Storage of 100% biodiesel should be at temperatures above 50°F.
Biodiesel should pose few problems as long as storage terminals are prepared and informed.