| In this study pyrolysis experiments were performed on pulverized samples (200 x 270 mesh) of Montana Rosebud subbituminous coal at a temperature of 1189 K, applied nitrogen pressures of 100 to 900 psig and residence times between 0.1 to 1.7 seconds.;The solid products of pyrolysis were extracted with tetrahydrofuran (THF) with the extract representing the pyrolysis tars and the residue representing the char. The gaseous pyrolysis products were analyzed qualitatively and quantitatively by an on-line gas chromatograph. An infrared gas analyzer was used to continuously monitor the CO concentration in the outlet gas stream. This was used to determine when the reactor had reached steady state operation.;To obtain an unambiguous time-temperature history for the coal particles in the reactor prior to collection, modeling of particle residence times was performed. The results from the modeling were used to define the conditions under which the pyrolysis experiments were performed.;Proximate analyses of the raw coal and the chars produced during the pyrolysis experiments were performed. The data were then used to calculate weight loss due to pyrolysis by using the proximate ash as a tracer. Ultimate analyses were performed also on the raw coal, chars, and tars obtained from pyrolysis. The effect of pressure and residence time on the product yield and distribution was determined. The data indicated that both the applied pressure and residence time affected the pyrolysis product yield and composition.;The chars generated by pyrolysis following rapid heating were characterized further by the following physical and chemical analyses: particle size distribution, Scanning Electron Microscopy (SEM), He density, N... |
