Assuring accurate biofuel blend measurements with portable mid-IR analyzers
With the public image vacillating between food versus fuel issues and the environmental advantage of biofuels, it is important to keep quality blend standards high in order to further biofuels acceptance. Analytical testing equipment is essential to this goal. Portable mid-infrared analyzers, such as the InfraCal Analyzers from Wilks Enterprise, Inc., offer a quick analytical method to assess the blend ratio of either biodiesel in diesel or ethanol in gasoline and can be a valuable asset for fuel distributors, terminal managers, fleet operators, and regulatory agencies.
The most common and least accurate method of blending used for biodiesel is splash blending. With splash blending, diesel and biodiesel are pumped separately into the delivery truck. The hope is that the blend will be adequately mixed by the time the truck gets to the delivery site. During a demonstration with an InfraCal Biodiesel Blend Analyzer, five minutes after splash filling a truck for a 20 percent biodiesel blend (B20), a sample taken from the top of the truck measured as 11.9 percent biodiesel and the bottom was 24.1 percent. The first delivery was less than 4 miles away offering little chance for a thorough mix.
As more mandates for minimum blends of ethanol in gasoline come into effect, major oil companies are mixing higher percentages of ethanol at their terminals. Although manufacturers of in-line blending systems claim indisputable accuracy, a quick check for the correct blend gives real data to a claimed assumption.
The InfraCal Biodiesel Blend Analyzer and the InfraCal Ethanol Blend Analyzer are preset to measure one wavelength specified for the measurement. The biodiesel ester has characteristic absorption in the mid-infrared at the carbonyl band (5.7 micrometers or 1745 cm-1). Ethanol has an infrared absorbance band unique to gasoline at 9.6 micrometers (1042 cm-1). The InfraCal Analyzers are self contained with an internal calibration program and direct readout display. They are ideal instruments for use where a single, repetitive analysis is needed.
For multiple analysis capabilities, the InfraSpec VFA-IR Spectrometer is a spectral range analyzer that can measure ethanol in gasoline, water in ethanol/methanol as well as % biodiesel in diesel and some fuel contaminants. It is operated from a PC allowing for multiple calibrations, data storage and data transmission.
All of these analyzers provide accurate and simple on-site analysis that takes less than 5 minutes. Having a quick analytical method and portable analyzers to assess the fuel blend quality help the industry insure the high standards that are needed for public acceptance of biofuels.