Calculation of Calorific Value of Coal/Char from Its Ultimate Analysis

摘要

A new correlation developed to calculate calorific (heating) value of coal and char from their elemental composition is significantly better than other similar correlations. The correlation was developed by means of regression analysis of a large data bank of US coals. A new correlation was needed because of the more accurate heating value estimation required by engineering calculations around coal conversion reactors. The only previously available correlations did not give satisfactory results when applied to the data bank of US coals. The new correlation resulted in a standard deviation of 129 Btu/lb for all ranks of coal as compared to a range of 139 to 222 Btu/lb for other formulas. The other correlations did not give better results than the new formula, not even on the modified Parr basis that accounts for the pyrite content of coal. Analysis of variances indicated that about 25% of the variance between the observed and calculated values can be accounted for by the variance in the experimental determinations of heating values and elemental composition. The rest may be attributed to the varying maceral and mineral compositions and possibly to a lower level of precision of the determinations of the data bank.