Animal Fat-Based Biodiesel: Explore Its Untapped Potential
According to scientific studies, both animal fat- and plant-based biodiesel contain the same chemical constituents-only the proportions vary. Both reduce unburned hydrocarbons, carbon monoxide and particulates. Both are biodegradable, nontoxic and safe to use in diesel engines with no modifications. Both are completely renewable sources of energy.
Animal fat-based biodiesel gained a poor reputation in the early years of the industry because some producers ignored quality standards and did not adequately manage their chemistry or downstream refining. Today, there are many high-quality animal fat-based biodiesel producers that offer ASTM and/or EN specification product to their customers.
Consider the facts:
Cetane number and emissions: The cetane number measures ignition quality of the fuel. The higher the number, the better. Soybean oil-based biodiesel averages between 46 and 52, while that of conventional diesel falls between 40 and 52. Animal fat-based biodiesel is between 56 and 60. Inadequate cetane numbers result in poor ignition quality and delay, abnormal combustion, excessive engine knock and smoke on cold starts. In addition to improving fuel combustion, increasing cetane levels often reduces emissions of nitrogen oxides and particulate matter. Animal fat-based biodiesel also provides added lubricity, a measure of protective compounds in the fuel that reduce engine wear and tear.
Cold-weather performance: Winter performance is an issue for all biodiesel, regardless of feedstock. While its higher cloud point means animal fat-based biodiesel freezes at a higher temperature than its plant oil-based counterparts, extensive testing has shown virtually no impact in B5 blends.
Engine suitability: If it meets ASTM standards, animal fat-based biodiesel is safe to use in all diesel engines. Most original equipment manufacturer dealers and customer service departments recommend B5 blends, while some promote B20 blends. Like other biodiesel, it acts as a solvent, releasing the deposits that build up after using petroleum-based diesel. For that reason, based on how biodiesel use is implemented, filters should be checked regularly and may need to be changed more often.
Sustainability: While all biodiesel is greener than petroleum-based diesel, animal fat-based biodiesel offers the most sustainable choice because it uses byproducts as a feedstock instead of relying on virgin materials. In addition, scientific studies continue to show better greenhouse gas reductions from the use of animal fats to produce biodiesel.
Stability: Without modifications or treatment, biodiesel can form sediments during storage. However, the higher percentage of saturated fats in animal fat-based biodiesel provides greater oxidative stability than its plant oil-based counterparts, reducing the risk of sedimentation.
Supply: American meat production shows no signs of slowing as the USDA predicts continued growth of 1 percent per year. That guarantees a steady supply of tallow and fats. With only 3 percent to 8 percent of animal fats and tallow being used for biodiesel production, there's no shortage of feedstock to supply North America's booming biodiesel industry.
The bottom line is that if biodiesel meets the prevalent ASTM specification, the feedstock used to produce it should not be a question. Animal fat-based biodiesel continues to measure up. In order to meet our renewable fuel obligations, we need to start taking advantage of a promising resource.
Jeremy Goodfellow is vice president of energy for Sanimax. Reach him at email@example.com or (800) 263-7430.