Diode Laser Raman Scattering Prototype for Continuous On-Site Characterization of Fuels and Environmental Contaminants

Period of Performance: 02/14/1996 - 05/28/1998


Phase 2 SBIR

Recipient Firm

Process Instruments, Inc.
825 North, 300 West, Suite 225
Salt Lake City, UT 84103
Principal Investigator

Research Topics


We propose to develop a diode-laser-based, full-spectrum Raman scattering instrument prototype incorporating fiber-optic coupling for rapid, continuous on-line and remote monitoring of key petrochemical processes. Narrow, well-defined peaks and insensitivity to moisture contamination allow for full-spectrum Raman detection with better than 0.1% sensitivity for liquid hydrocarbons within 30 to 60 seconds. Traditional Raman scattering performed with visible light excitation is not compatible with liquid hydrocarbon systems because of background fluorescence. Conventional gas lasers have too short of a life and are too expensive for routine commercial instrumentation. A semiconductor laser diode offers longer life than conventional lasers and can operate at near-IR wavelengths where sample fluorescence is minimized while taking advantage of the very sensitive and full-spectrum capabilities of silicon CCD array Raman spectrum detection. Fiber-optic coupling allows the safe application of Raman scattering in hazardous environments, eliminates lag time, and reduces maintenance of sample handling systems while affording remote location of vibration sensitive equipment. Phase I demonstrated the ability of Raman technology to quickly measure gasoline components including individual aromatics, such as benzene, xylenes, iso-octane, olefin content, unique brand formulations and octane ratings. Phase II is a productive development plan to build a rugged, reliable and cost effective instrument including an efficient volume holographic spectrometer, application specific software, user interface, calibration procedures and appropriate packaging. The prototypes will be tested on-line in actual refinery applications.| Benefits: Rapid on-line determination of gasoline manufacturing processes can save the petroleum industry $300,000,000 per year through tighter control of octane ratings, air pollutants (olefins), alkylation acid, carcinogens (benzene) content and numerous EPA mandated oxygenated additives including MTBE and ETBE.|