The direct use of pulverized coal in combustion applications, although an economically attractive technology, is limited at present by certain environmental and surface-degradation problems. Incombustible, inorganic constituents of coal deposit as submicron, and supermicron sized particles on relatively cool heat exchanger surfaces. In addition, sulfur in the coal is released in the form of sulfur dioxide and trioxide vapors during combustion. These barrier issues'need to be addressed at the fundamental level before coal can be considered a viable, competitive fuel. The deposition and corrosion problems are particularly important in the direct-fired gas turbine technology which is still in a stage of development. In order to better understand and control the complex problem of deposition, it is necessary first to accurately define the environment in which the combustion of coal particles take place. The global objective of this research was to provide experimental and theoretical frame work with which different coals combusting in different environments can be evaluated for their fouling potential and that deposition control strategies can be formulated. Therefore, the following tasks were undertaken: (1) development of and testing of a particle -- temperature measurement technique via four-color pyrometry (2) analysis of the flow and temperature field of an entrained flow reactor which would be used for combustion-deposition studies of pulverized coal particles (3) development and testing of a gas-temperature measurement technique using a Fourier transformed -- infrared (FT-IR) spectrometer in high temperature gas streams. Results are discussed. 51 refs., 36 figs., 4 tabs.