An alternative representation of coal composition data

The two best known coal composition charts are Seyler's plot of mass percent hydrogen versus mass percent carbon, which has been much used for coal classification, and van Krevelen's plot of atomic H/C ratio versus O/C ratio, which has proved useful in the study of coalification. For the more general problem of the study of conversion of coal to other materials it is suggested that a ternary carbon/ hydrogen/oxygen diagram be used. In particular it is advocated that the compositions be plotted as bond-equivalent percentages, i.e. with each element given a weighting appropriate to its power of combining with the other elements. The construction and use of the diagram are demonstrated, taking as an example the problem of the conversion of brown coal to oil.