September 17, 2011
Journal Article

High temperature millimeter wave radiometric and interferometric measurements of slag-refractory interaction for application to coal gasifiers

Abstract

Millimeter wave (MMW) radiometry can be used for simultaneous measurement of emissivity and temperature of materials under extreme environments (high temperature, pressure, and corrosive environments) such as in slagging coal gasifiers, where sensors have been identified as a key enabling technology need for process optimization. We present a state-of-the-art dual-channel MMW heterodyne radiometer with active interferometric capability that allows simultaneous radiometric measurements of sample temperature, emissivity, and flow dynamics to over 1873 K. Interferometric capability is supplied via a probe signal originating from the 137 GHz radiometer local oscillator (LO). The interferometric “video” channels allow measurement of additional parameters simultaneously, such as volume expansion, thickness change, and slag viscosity along with temperature or emissivity. This capability has been used to demonstrate measurement of temperature and simulated coal slag infiltration into a chromia refractory brick sample as well as slag flow down a vertically placed refractory brick. Observed phenomena include slag melting and slumping, slag reboil and foam with oxygen evolution, and eventual failure of the alumina crucible through corrosion by the molten slag. These results show the promise of the MMW system for extracting quantitative and qualitative process parameters from operating slagging coal gasifiers, providing valuable information for process efficiency, control, and increased productivity.

Revised: November 28, 2011 | Published: September 17, 2011

Citation

McCloy J.S., J.V. Crum, S.K. Sundaram, R.W. Slaugh, and P.P. Woskov. 2011. High temperature millimeter wave radiometric and interferometric measurements of slag-refractory interaction for application to coal gasifiers. Journal of Infrared, Millimeter and Terahertz Waves 32, no. 11:1337-1349. PNNL-SA-77184. doi:10.1007/s10762-011-9823-4