International calls to reduce our collective dependence on fossil fuels result in the need, and opportunity, for greater supply of alternative fuels and fuel additives. The use of biofuels—fuels derived from plants and renewable materials—is growing steadily, driven by socioeconomic demands for more responsible use of natural resources with less negative impact on the environment. In the US, bioethanol is blended into nearly half of the nation’s gasoline, while other countries are focused on biodiesel. Additionally, researchers are doing biofuel research on other agricultural by-products such as cellulosic feedstocks and algae, which hold the promise of greater sustainability and capacity.

To successfully meet market demands, manufacturers need to lower production costs and increase yields. As a result, the use of near-infrared (NIR) spectroscopy, sometimes referred to as NIRS, is rapidly increasing throughout the growing bioenergy industry. NIR is extremely effective for determination of oil content of soybeans, corn, rape seed, algae and other crops, as well as quantification of key parameter levels in bio-oils. The increased use of NIR analysis is directly attributable to the cost-effective operational ease and reliable nature of NIR as an analytical tool.

• Real-time in situ analysis
• Non-destructive, repeatable testing
• Ability to measure multiple constituents simultaneously
• No sample prep
• No chemical waste stream, environmentally friendly
• Lower costs

The quality of biofuels is critical to performance and acceptance in the market. Standards-setting organizations in the United States and Europe have designated metrics (US: ASTM D-6751-03 and D5798-99; Europe: CEN 14214 and prEN 15376:2006) for biofuel quality.

NIR can reliably and accurately quantify levels of key parameters in raw fuel material, including:

• Moisture
• Total Glycerin
• Glycerides (mono, di, and tri)
• Fatty acid ethyl esters (FAEEs)
• Fatty acid methyl esters (FAMEs)
• Viscocity
• Cloud point

Shown right: LabSpec^® 5000 portable NIR analyzer on the goLab™ Mobile Work Station for the ultimate portable analysis and quality testing.

NIR is ideally suited to the measurement of combination and overtone absorptions of C-H, O-H, and N-H, bonds, common in nearly all organic systems. NIR is, therefore, applicable to almost all qualitative (ID) and quantitative (concentration) analyses of organic systems. By using NIR to measure biolipid parameters, processors can make the necessary adjustments during the process to account for variations in levels of moisture and Free Fatty Acids (FFAs).

Through precision measuring of moisture prior to purification, the necessary amount of drying agent and/or the correct timing to heat the biolipid (oil or fat) to remove free water can be assessed more accurately. Any remaining water in the process can promote the saponification reaction and inhibit the transesterification reaction.

After purification, NIR can be used to measure FFA content. By measuring FFA, process engineers can more accurately control the amount of base (typically NaOH) required for the neutralization of the FFA, thereby greatly increasing production quality, and eliminating unnecessary NaOH waste.

In May of 2008 Biodiesel Magazine published an article contributed by ASD’s application specialists, “Demystifying Near-Infrared Analysis for Biodiesel Production,” which covers this process more in depth. Request your copy today by clicking on the link above.