GC-FIMS for Analyzing Transportation Fuels

To comply with new regulations and to optimize and control refinery operations, a technique is needed for rapidly analyzing transportation fuels (gasoline, jet fuel, diesel) to provide a detailed breakdown of hydrocarbon types by the carbon number.

SRI has modified a bench top gas chromatograph (GC) equipped with a mass selective detector (MSD) by replacing the standard electron impact (EI) source with an SRI volcano-style field ionization (FI) source. Unlike EI ionization, which causes extensive fragmentation, field ionization forms the molecular ion only, and various peaks in an FI mass spectrum can be reliably interpreted to be due to molecular ions. Thus, in a GC-FIMS, the burden of resolving components can be shared between the chromatograph and the mass spectrometer. This feature allows one to use relatively short columns and fast heat-up ramps to drastically reduce analysis time to less than 15 min.

Learn more about this capability by viewing our presentation and recent paper.

Advantage
From the detailed hydrocarbon breakdown provided by the GC-FIMS, it should be possible to readily calculate (or correlate) many of the fuel properties such as aromatics content, density, vapor pressure, distillation behavior, freezing point, and octane and cetane numbers, thus, many tests normally performed on each batch for quality control and regulatory compliance can be replaced by one GC-FIMS analysis.

The technique is rapid enough to be used for process control by monitoring the product streams. If the products fall outside the specified range, a corrective action could be taken and the need to blend it with other streams to meet specifications can be minimized. The analysis can also be used to see if the hydrogen in the system is being used optimally and thus is a useful tool for Process R&D.

Opportunity
SRI International is seeking partners to support its effort in developing GC-FIMS as the analytical technique of choice for petroleum processing. Prospective partners can interact with us by

• Sending samples to SRI for analysis. Our standard rate for analyzing including interpretation of the data is $500 per sample with a minimum of 5 samples.
• Supporting research either individually or jointly with others to develop methods for analyzing and calculating specific properties as well as other applications.
• Obtaining from SRI a GC-FIMS instrument or having SRI retrofit one of your own.

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Technical Contact:
Ripudaman Malhotra
(650) 859-2805
ripudaman.malhotra@sri.com