A TXRF System for Mercury Emissions Monitoring

The Mercury and Air Toxics Standards (MATS) require coal-fired power plants to limit mercury emissions to tenths to ten-thousandths of a pound/gigawatt-hour of gross electrical output. Current methods for measuring mercury for continuous emission testing involve cold-vapor atomic absorption (CVAAS) spectroscopy, cold vapor atomic fluorescence (CVAFS), inductively coupled plasma-mass spectrometry (ICP-MS), gas chromatography-mass spectrometry (GC-MS), and energy dispersive x-ray fluorescence (ED-XRF)]. Recent advances in X-ray tube technologies as well as new analytical methods utilizing those technologies have shed light on new X-Ray analytical techniques that greatly enhance the sensitivity of the detection and measurement. In particular total external reflection X-Ray Fluorescence analysis (TXRF) has been developed and has proven to increase the signal to noise ratio so that the limit of detection has been found to increase from 200% to as much as five orders of magnitude. In this Phase I project we propose to further develop the XRF analytical method for Hg CEM by incorporating a TER-XRF method that would allow for a large enhancement to the limit of detection as well as the relative accuracy measurements.