RI 5904 Low-Temperature Carbonization Assays Of Coals And Relation Of Yields To Analyses ? Summary And Conclusions

In contrast to the large fund of information available on the carbonizing properties of Eastern U.S. coals, the experimental data available for most Western U.S. and foreign coals are meager. To supply some self-consistent data, the Bureau of Mines conducted 220 low-temperature carbonization assay tests at 500° C. in a laboratory-scale carbonization apparatus. The results are included in this report. The U.S. coals tested are from Alaska, Arizona, Colorado, Illinois, Montana, New Mexico, North Dakota, Pennsylvania, Ohio, Texas, Utah, and Wyoming. Assays were also made on coals from Canada, Ecuador, France, Greece, India, Mexico, the Philippine Islands, Thailand, and Yugoslavia. In addition, one assay of pine sawdust and one assay of a peat from Ireland are reported. Prediction equations were developed relating the yield of products of carbonization obtained at 500° C. in the assay unit to the proximate and ultimate analyses of the coals. The equations for predicting the yields of tar plus light oil, char, and gas, and the heating value of the gas, are considered good, each equation having a multiple correlation coefficient of 0.90 or higher. The equation predicting volume of gas obtained upon carbonization is considered as fair, with a multiple correlation coefficient of 0.84. A reproducibility study of the assay made on 10 replicate samples of a subbituminous coal indicated that the standard deviation of the individual products was 0.31 percent or less.