Biodiesel Analysis Utilizing Mini-Scan - Handheld Analyzer V.C. Gordon PhD, Bonanza Labs Overview According to the National Biodiesel Board, biodiesel production in the United States reached 450 million gallons in 2007. As a result of minimum biofuel blend requirements set forth in The Energy Independence and Security Act of 2007, biodiesel usage was expected to expand to 500 million gallons by 2009 and possibly to 1 billion gallons by 2012. Changes in tax credits, industry uncertainty and feedstock pricing and changes caused many plants to shutter in the U.S. Production has increased in many other countries but not here in the U.S. New feedstocks which are not considered food are being heavily investigated such as algae and jatropha. With these changes, testing must be feedstock independent and be available for lower cost. Testing must be rapid and simple and low cost for today s plant and industry to succeed financially. The Mini-Scan Testing System The Mini-Scan is a handheld biodiesel analyzer which can be used by anyone from the plant throughout the distribution chain. The device uses UV/VIS Spectroscopy coupled with chemical and biochemical Detection Analysis which has demonstrated excellent correlation to traditional reference methods to test many critical parameters in the plant and field. Mini-Scan can test for FFA and oil content in incoming feedstock in minutes, for total glycerin (TG), and acid number in B100 samples and can measure blend per cent in blended samples. This portable testing unit is extremely easy to use and provides results which can be downloaded with a flash drive for computer storage and viewing.
Figure 1. Mini-Scan Handheld Biodiesel Analyzer Results from the Mini-Scan are quantitative for total glycerin to 0.03%. The determination for Acid Number is within 0.1 units and for FFA within 0.2%. No interpretations are necessary, nor are subjective observations used to evaluate results. Correlation of Mini-Scan Data to ASTM Determinations The acquisition of TG, FFA and AN data was performed on a substantial population of samples. The samples included a variety feedstocks and of B100 fluids from multiple feedstocks. Regression analysis was performed to determine correlations between Mini-Scan data variables and 1) Total Glycerin concentration (ASTM 6584) and AN (ASTM 664) and FFA (ASTM D684).
The following other methods and Reference Methods were used to evaluate Mini-scan capabilities Total Glycerin (0.03-0.7 %) Gas Chromatography (ASTM 6584) SAFTEST Acid Number (0.2 3.5) Titration (ASTM 664) SAFTEST Free Fatty Acids (0.1-25) Titration (ASTM D684 ) SAFTEST Total Glycerin Evaluation The reference standard (ASTM D6584) for biodiesel total glycerin concentration utilizes gas chromatography for the quantitative detection of glycerol (free); mono, di and triglyceride species (bound glycerides). Evaluation of B100 samples via this standard technique has been employed at Bonanza and at an external analytical laboratory. The fuels investigated include a variety of B100 samples from multiple feedstocks, including those in and out of specification (ASTM D6751) for total glycerin concentration. (See Figure 2.)
0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 ASTM Total Glycerin Figure 2. Mini-Scan Total Glycerin versus GC Total Glycerin Figure 2 Illustrates that total glycerin content determined measurements is very well correlated (r2=.98) with that found using the ASTM D6584 - GC standard.
A more recent study on 10 biodiesel sample demonstrates the excellent correlation between Mini-Scan Results and GC. See Figure 3. 10 sample correlation 0.99 Figure 3. Comparison TG results on Mini-Scan to GC results Free Fatty Acid Evaluation In 2010, 16 feedstocks were studied which were mixed waste and mixed feedstocks. The Mini-Scan results are compared to the titration results for these 16 samples with excellent correlation. See Figure 4.
16 sample correlation 0.99 Figure 4. Comparison of Mini-Scan FFA results to Titration results on 16 samples Acid Number Evaluation Mini-Scan measurements were correlated to the ASTM reference titration method to determine Acid Number. See Figure 5.
Mini Scan AN results versus Titra3on A N 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0 0 0.2 0.4 0.6 0.8 1 1.2 1.4 Mini Scan Figure 5. Acid Number D684 versus Mini-Scan Acid Number This data can be used to determine if a B100 sample passes the specification of < 0.5. For the number of samples, the samples passing specification by Mini-Scan was compared to titration. Lab-to-Lab Evaluations Lab-to-Lab Evaluations on the Mini-Scan Total Glycerin results on 6 samples was performed. These results demonstrate the excellent correlation between labs running the Mini-scan method. See Figure 6.
6 sample lab to lab Figure 6. Mini-Scan Results on Total Glycerin in Two Labs Conclusions The Mini-Scan is fully able to determine total glycerin in B100 from 0.03-0.7% and results exhibit excellent correlation to the results from GC. Total glycerin determinations using Mini-Scan in two labs demonstrates repeatability. Determinations of acid number with Mini-Scan also demonstrate excellent correlation to the ASTM titration method and these 5 second tests enable those in the biofuel production industry to rapidly assess the presence of degradation at the plant and throughout the distribution chain. FFA can be determine in seconds using the Mini-Scan and demonstrate excellent correlation to the titration method. Mini-Scan with its reliability, accuracy and ease of use make it an essential tool for those rendering and qualifying feedstock, producing biodiesel and blending and distributing biodiesel in today s market.