A DEVELOPMENT OF ON-LINE TEMPERATURE MEASUREMENT INSTRUMENTATION FOR GASIFICATION PROCESS CONTROL

This progress report covers continuing work to develop a temperature probe for a coal gasifier. A workable probe design requires finding answers to crucial questions involving the probe materials. We report on attempts to answer those questions. We attempted to measure the laser-input power at a wavelength of 355 nm that would damage the ends of sapphire fiber optics. We were surprised and pleased to learn that they survived an input power density of about 3 x 10{sup 9} W/cm{sup 2}, which greatly exceeds the best that fused-silica fibers can do. During a run of our new simulator to obtain an upgraded calibration curve for the improved YAG:Dy phosphors, we found that the phosphor appeared to form a eutectic, with the fused-silica cuvette used to hold the phosphor, when the temperature exceeded 1450 C. This result could have substantial ramifications in this and other high-temperature applications. Our new proprietary detector package that replaced the original photomultiplier tube gave excellent results, with much better signal-to-noise ratio at a given temperature than the old package. Our new plasma-spraying operation has succeeded in spraying YAG, which we think may be a technological breakthrough