|Recent Advances in the Analysis of Petroleum-based Fuels using Gas Chromatography-Vacuum Ultraviolet Spectroscopy
|Analysis of Complex Energy Products
|Mr James Diekmann
|Mr Jack Cochran
Dr Philp Walsh
Mr Dan Wispinski
Abstract Information :
Gasoline is the primary transportation fuel in our society today and plays a pivotal role in the global economy. One of the many ways refineries across the world analyze their finished fuel products is by gas chromatography - flame ionization detector (GC-FID). Typically, "detailed hydrocarbon analysis" (DHA) or a multidimensional GC (MDGC) approach is used for determining hydrocarbons in these complex samples. DHA is a 3-hour method that requires a pre-column that must be "tuned" connected to a 100m x 0.25mm x 1.00µm GC column to separate and speciate as many compounds as possible. The MDGC analysis is a 1-hour method that uses a complicated series of valves and columns and traps to separate and group by compound classes and carbon numbers.
Recently, VUV Analytics developed an alternative method for gasoline hydrocarbon analysis using GC - Vacuum Ultraviolet (VUV) absorbance spectroscopy for finished gasoline and gasoline-range product streams. Unlike DHA and MDGC, GC-VUV simplifies the setup and speeds up the analysis by using a single 30m x 0.25mm x 0.25µm polydimethylsiloxane GC column. This 30-minute method employs rapid spectroscopic deconvolution to produce hydrocarbon class and carbon number breakdown for samples, while still providing some compound speciation (e.g., iso-octane, benzene, toluene, ethylbenzene, xylenes, naphthalene, methylnaphthalenes, and select oxygenates). The method has been propagated as ASTM D8071-17, Standard Test Method for Determination of Hydrocarbon Group Types and Select Hydrocarbon and Oxygenate Compounds in Automotive Spark-Ignition Engine Fuel Using Gas Chromatography with Vacuum Ultraviolet Absorption Spectroscopy Detection (GC-VUV).
In this presentation, we present the recent advances in the characterization of petroleum-based fuels using GC-VUV, as an alternative to current techniques that are time-consuming, cumbersome, and/or complicated. We investigate the possibility of reducing the GC-VUV runtime by half with modifications to simple GC parameters such as flow rate and oven ramp. We also highlight the feasibility of speciating compounds outside the scope of ASTM D8071.