Analysis of Hydrocarbons by In-line GC/MS

Poster Presentation

Prepared by P. Macek1, H. Chelliah2
1 - Shimadzu Scientific Insruments, Inc., 7102 Riverwood Dr., Columbia, MD, 21046, United States
2 - University of Virginia, Mechanical and Aerospace Engineering, University of Virginia, Charlottesville, VA, 22904, United States

Contact Information:; 804-432-8912


Liquid hydrocarbon fuels are one of the major sources of energy in the world. Although other sources of energy like solar and nuclear power are growing rapidly, fossil fuel and especially liquid petroleum will serve most of the energy needs for transportation at least for two decades. Use of these fuels is connected with emissions of carbon dioxide, carbon monoxide, nitrogen oxides (NOx), sulfur oxides (SOx), hydrocarbons and soot particles. The current work is exploring the reaction mechanisms of soot formation in jet engines. Jet fuel is an ensemble of hundreds of hydrocarbons. A reactive system using these fuels may have a huge number of additional stable and radical species involved in thousands of elementary reactions. The current work involves design and fabrication of micro flow tube reactor with minimal experimental uncertainties. The goal is to validate the reactor configuration by conducting thermal pyrolysis of hydrocarbon fuels and to extend the work to pyrolysis of real aviation fuels. Because accurate reaction mechanisms are known for ethane, butane and dodecane (a popular jet fuel surrogate), those compounds were chosen as reference fuels to validate the reactor. The small molecule work has been completed. The pyrolysis products were successfully analyzed, and with a custom designed in-line GC, equipped with FID and TCD. The current experiments include thermal pyrolysis of real fuels like JP-8 and JP-10 in addition to surrogate compounds. Clearly, there are larger molecules in the effluent that must be accounted for by some analytical means. This work will extend the successful GC/FID/TCD work that has been done on small molecules to in-line GC/MS analysis of larger molecules. The main challenge has been to develop a viable calibration procedure for the larger less volatile molecules. Because the sampling probe is part of the analytical system and not part of the reactor, this technique could be extended for use in other applications where rapid atmospheric testing of unknown compounds is required.