FEW: Spectroscopy tools come in handy

By Jessica Sobolik | June 02, 2008
Web exclusive posted June 17, 2008 at 9:23 p.m. CST

Analytical methods may not sound sexy, but they are vital in all ethanol plants for the monitoring of various stages of the production process. Among other benefits, these methods can indicate to plant operators the potential for infections long before they are obviously apparent, so they can add more antibiotics (as one option) and save plants from costly cleaning processes. The concept was discussed in depth in a breakout session at the 2008 International Fuel Ethanol Workshop & Expo in Nashville on June 17.

Analytical methods are mainly used in three areas of the plant, according to Ronny Pradon, market manager of biofuel, brewing and distilling at Sweden-based Foss. These are the front end, the midsection and the back end. In the front end, near-infrared (NIR) spectroscopy technology reflects light onto corn kernels coming into the plant to calculate ethanol yield through moisture, starch, protein and oil content, according to Yan Wang, applications scientist for Bruker Optics. On the back end but in the same way, the analyzer indicates the moisture, fat, fiber, ash and protein content of distillers grains. These analyses are needed to indicate value for the incoming feedstock and quality of the coproduct.

In between the front and back end, analytical methods are necessary during fermentation to prevent infections. Pradon said his company has yet to make an NIR analysis work here. Because at that point in the process the sample is now "alive" with yeast and enzymes, it can't easily be transported to the front or back end without a change in content. Therefore, on June 13, Foss unveiled a new fermentation analyzer, the BioFoss, which uses Fourier transform infrared (FTIR) spectroscopy technology to measure not only ethanol, but also acetic acid, lactic acid, glucose, glycerol, maltose (a disaccharide or DP2), trisaccharides (DP3), DP4 and pH in fermentation samples. Foss told EPM this type of analysis was previously done with high-pressure liquid chromatography. However, this can be time-consuming, operator-dependent and expensive. The FTIR analysis takes two minutes and doesn't use chemical reagents. FTIR is better basically because it has a broader range of spectrum, Pradon said.

The BioFoss is on display at the FEW Expo.