French-Fry Fuel - Text-only Version

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IT’S IN THE NEWS EVERY DAY, IF NOT EVERY HOUR: petropolitics, the current volatility of the Middle East and its valuable oil supply. The industrial might, economy and defense of our country are all too dependent on a tenuous overseas supply of petroleum.

What if we could substantially reduce that dependency using a domestically supplied energy source? Several U.S. government agencies, along with countless private enterprises, are working on an answer to this very question.

The alternatives include propane and natural gas, methanol, fuel cells and solar power. But there is another alternative fuel that may hold the key at least to reducing this country’s current dependence on mineral-based petroleum, both foreign and domestic: biodiesel.

Biodiesel (BD) is the generic name given to a liquid fuel derived from vegetable oils, animal fats, cooking oils and greases. These may be virgin or re-refined from restaurant deep fryers. That’s right—the same oil that your French fries or onion rings were cooked in today may power your diesel engine tomorrow.

Unfortunately, these oils cannot go straight from the vegetable press to the fuel tank. Some experimental diesel engine vehicles have actually run across the country on raw fast-food deep-fryer oils, but this is purely experimental and not practical. These raw greases solidify to the consistency of lard or butter at the relatively high temperature of 50–60 degrees Fahrenheit. In order to prevent this, the experimental vehicles utilize fuel system heaters (tank, fuel lines, filters—everything must be kept warm) to keep the oil from congealing. If you’ve ever cleaned a deep fryer, you know how difficult this can be.

French Fries And Onion Bits

In order to produce BD, these oils go through a sophisticated refining process known as esterification. In this veggie “cracking” procedure, the oils and fats are filtered to remove water and contaminants (for recycled cooking oils this may include French fries and onion bits). These fats and oils are then chemically reacted with alcohol, most often methanol, and a catalyst, usually sodium or potassium hydroxide, which produces a chemical compound known as fatty acid methyl esters, or FAMEs. When intended for use as a motor fuel, FAMEs are termed biodiesel. A useful byproduct of this process is glycerol, which may be used in cosmetics and pharmaceuticals.

About half of the biodiesel industry is capable of using any fat or vegetable oil, including recycled cooking grease, as “crude.” The remainder of the industry is limited to using virgin vegetable oils, the least expensive and most available of which is soy oil. In fact, the soybean industry has been responsible for much of the commercialization of BD as a result of declining prices for their product and excess production. In simple terms, there’s too much supply and not enough demand. BD production may change that scenario in the not too distant future. The same issues apply to the recycled restaurant grease and animal fats industry, although their product is less expensive than other raw oils, such as soy and rapeseed.

Fill’er Up

At this point you may be asking, if biodiesel is so good, why aren’t there biodiesel pumps at every filling station and fuel dock? The reasons are many and varied.

The primary disadvantage of BD, and the hurdle it must overcome in order to become more widely used in this country, is its high cost. Depending on where and how much you purchase, BD costs anywhere from $1.50 to $3.50 per gallon, and this fluctuates depending on the price of the crude stock, be it soybeans or used fast-food deep-fry fat.

Other obstacles biodiesel faces include high “cloud” and “pour” points. The former is the temperature at which diesel, or any fuel, begins to form wax crystals (the fuel actually looks cloudy), which will clog fuel filters until the temperature rises. Naturally, this is a problem for cold weather operation. The latter refers to the fuel’s ability to remain in a liquid state. BD will, because of its vegetable oil ancestry, thicken at a relatively high temperature. The cloud and pour points of pure biodiesel (referred to as B100, or 100 percent biodiesel, as opposed to a mixture of ordinary diesel fuel and biodiesel) are 12–60 degrees Fahrenheit and 5–55 degrees Fahrenheit, respectively. This is a comparatively wide gap and one that would cause some concern even in temperate areas. Typically, however, anecdotal evidence indicates that problems begin to arise at about 40 degrees.

As a comparison, conventional No. 2 diesel fuel, 2D, should possess a cloud point of between 15 and 34 degrees. It should, however, be at least 10 degrees below the lowest temperature at which the engine or vessel will be operated. Pour point varies by season, region and refinery, but it usually ranges from 0–10 degrees Fahrenheit.

s indicated above, the operating temperature gap between bio and conventional diesel is considerable. It can cause problems in cool weather. This deficit may be mitigated by mixing biodiesel with conventional diesel at anywhere from a 1:19 to 1:4 ratio, biodiesel to conventional diesel.

Industry Roadblock

Another considerable stumbling block that stands in the way of widespread acceptance and use of BD is the resistance of diesel engine manufacturers. While they are nearly unanimous in their desire to embrace alternative fuels, especially those that fall under the umbrella of governmental incentives or environmental legislation, as BD does, some stop short of endorsing biodiesel. For example, Caterpillar’s literature says, “Caterpillar neither approves nor prohibits the use of biodiesel fuels” and Cummins’ indicates that “biodiesel fuels must be considered experimental at this time” and adds that “failures caused by the use of biodiesel fuels are NOT defects of Cummins parts or workmanship and therefore would NOT be covered by Cummins’ warranty.” Cummins does suggest that if BD is used that this be done with blends of 5 percent (5 percent biodiesel, 95 percent distillate diesel) rather than “neat,” 100 percent biodiesel.

Yanmar’s position is, “up to 5 percent volume blend RME or SME blend, which complies with the existing quality standards, should not give end users any serious problems.” A Yanmar service bulletin goes on to say, “Yanmar, through this advisory, clarifies the acceptance of biodiesel blend in diesel fuel only when the blend does not exceed over 5 percent biodiesel.” These are not exactly ringing endorsements of biodiesel, but neither are they a prohibition against its use.

As with all new technology, however, there will be a learning and acceptance curve. One thing that makes the curve steeper is the propensity of BD to oxidize (essentially rot), absorb water, support microbial life and turn acidic over time. Actually, the beauty of BD is also one of its greatest weaknesses. Its proponents tout it as environmentally friendly because it biodegrades. But rotting, waterlogged fuel that’s eating away at your fuel tank is not exactly something most cruisers care to have aboard.

Vessel operators are warned, in some diesel engine manufacturer literature relating to BD, to keep vessel tanks as full as possible, protected from extreme temperatures and limit extended storage of biodiesel.

It’s difficult to keep real diesel fuel from being contaminated and going sour; thus, the operator who chooses to use BD must be doubly cautious about the above-mentioned fuel issues, among others.

Another particularly vexing problem faced by BD users is its ability to attack certain rubber and plastic components, such as fuel lines and plastic fuel filter bodies and bowls. Some literature indicates that any natural rubber components will be affected; others say it’s only components manufactured before 1994. The fact is, it’s still a bit of an unknown, so this guideline should not be taken as an absolute. Bob Sherman of Diesel Fuel Filtering Inc., of Alameda, California, reports that BD has affected his equipment. “It has distorted plastic filter components and softened Aeroquip fuel hoses to the point that they can no longer be used,” he says. His company will no longer filter fuel from tanks that either contain, or have ever contained, BD.

The Cleaner, Greener Fuel

This cloud does, however, have a silver lining. BD’s list of attributes is impressive and lengthy. Most importantly, it can be produced domestically and relatively easily. All of the necessary technology exists and is in operation. It’s not science fiction; it’s reality. Additionally, it is environmentally friendly. Without getting too scientific, diesel engines that use BD will produce less unburned hydrocarbons, carbon monoxide, sulfates, aromatic hydrocarbons and particulate matter. Nitrogen oxide, a harmful pollutant, does increase slightly with the burning of BD.

Users of BD report that it does not cause the noxious exhaust fumes associated with diesel; instead it produces a pleasant aroma not unlike that of French fries or popcorn. Additionally, because soot production is reduced, transoms tend to stay cleaner. Also of interest to those who like to give their diesels maximum TLC, BD has both higher lubricity (the slipperiness of the fuel is important because it acts as a lubricant for injectors and injection pumps) and cetane. The latter is a measure of the fuel’s ignition value, roughly similar to gasoline’s octane index. Ironically, adding BD to distillate diesel may actually improve its burning characteristics, increasing lubricity and cetane while reducing smoke and its unpleasant odor.

As is often the case, however, there’s a price to be paid for these advantages. BD is slightly less potent than ordinary diesel. BD provides approximately 5–9 percent less energy per gallon than distillate diesel fuel. Consequently, a corresponding reduction in available horsepower and fuel economy will be realized when using neat BD. Blends, usually in the 5–20-percent BD range, will suffer a less noticeable loss of power and economy.

As mentioned in the “disadvantages” section, BD does absorb water and oxidize easily, making it essentially biodegradable. Also previously mentioned are the advantages inherent in this trait. Spilled BD does not present nearly the ecological concern that spilled distillate diesel does. That’s not to say it’s OK to dump gallons of it on land or sea (you may have a hard time convincing the EPA or Coast Guard that it’s not diesel fuel, despite its appearance). Of course, this advantage only applies to pure BD and not BD-distillate diesel blends.

There are very compelling arguments both for and against the use of BD. We all want to maintain our diesels in top running order while keeping operating and maintenance costs low and engine reliability high. If you’re like me, using diesel fuel that’s anything less than the best, cleanest and most powerful money can buy, whether it’s in my boat, car or truck, is unthinkable. The thought of casting off the yoke of foreign oil dependence while being kinder and gentler to the environment is, however, equally as appealing.

If you are considering using BD, check with your engine manufacturer about guidelines for your engine and the BD you intend to use. Every diesel engine manufacturer I contacted was very responsive on the subject of bio-fuels, and they all produce written service bulletins and suggestions on the subject. Additionally, before making the switch, obtain from the BD retailer the specification for the BD product they are offering. Most engine manufacturers have agreed that in order for their engines to use BD, it must meet certain agreed-upon standards, one of which is ASTM standard PS 121-99 (which is provisional and subject to change) and/or DIN 51606. If the BD retailer will not supply, in writing, the standard for the fuel he or she is selling, go elsewhere.

Good Potential

I believe BD holds a great deal of potential for diesel engine users. When it becomes more widely accepted, and engine manufacturers become more familiar with its long-term effects on their products, it’s likely that the cost of producing it will decrease. Once it becomes economically competitive with distillate diesel, its use will increase, which should reduce production costs even further.

I’m in agreement with the Cummins service advisory statement, “Biodiesel must be considered experimental at this time.” If you opt to use it, it must be with this notion kept firmly in mind.

One should also remember the diesel engine was considered experimental a scant 100 years ago.

Steve D’Antonio is a PMM contributing editor and manager at Zimmerman Marine, a custom boatbuilding and repair yard on Mobjack Bay, in Cardinal, Virginia.

Reprinted with permission. Copyright 2003 © Dominion Enterprises (888.487.2953) www.passagemaker.com

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