The demand for on-line analyzers capable of compositional determinations in petroleum and chemical process streams has increased dramatically in recent years. Total control of production plant processes and resources requires the analysis of feed, intermediate, and product materials. This paper will describe a rugged, on-stream energy dispersive X-ray fluorescence (EDXRF) analyzer configured for the continuous determination of composition in solid and liquid samples. The detector in the X-ray sensor is a lithium-drifted silicon crystal which is thermoelectrically cooled (Peltier effect) to achieve operational temperatures. This approach to detector cooling offers advantages over traditional cryogenic liquid cooling when EDXRF is used in the process control environment.

Three applications of the thermoelectrically-cooled detector-based EDXRF spectrometer will be presented here. The first is the analysis of a catalyst solution to monitor depletion of the active species. Second, two components of a plating bath solution will be determined simultaneously in a flowing sample stream. In the third application, the spectrometer will be oriented in a downward looking configuration to monitor inorganic constituents in absorbent samples as they are transported by conveyor belt to the X-ray measurement area.