To insure the reliability of the coal conversion as well as carbon balance closure data, the feed flow rates and gas chromatograph response factors were recalibrated. Experiments were carried out with Zap A (lignite), Montana Rosebud (sub-bituminous), Pittsburgh No. 8 (bituminous) and Illinois No. 6 (bituminous) coals. For pre-designated flow conditions as per the test plan, char slurry and soot samples were collected. The char slurry samples were filtered and analyzed. Data of coal carbon conversion and pyrolyzed temperature as a function of coal loading, residence time and gas inlet temperature are presented. Good agreement between the gas compositions and coal carbon conversions was found at the pyrolyzer exit and cyclone exit indicating that the gas samples in the pyrolyzer and the char samples collected at the bottom of the cyclone are truly representative. The coal carbon conversion obtained from the char analysis using ash tracer technique indicated good agreement with that from the gas analysis. The reproducibility of the data was checked and was found to be fairly good. The char slurry samples were filtered and analyzed and from that the carbon balance closure was checked. To study the effect of particle size, experiments were carried out with 70% - 200 mesh and 95% - 325 mesh Rosebud coals. The coal carbon conversions were found to be similar in both cases. All of the data presented are in preliminary form, and will be subjected to further analysis before inclusion in the final report. 15 figs., 3 tabs.