r is the gas constant the model parameters a and u03b4e u2260 are the frequency factor and activation energy the degree of conversion a is give by the expression u03b1 m i u2212 m u03c4 m i u2212 m f where m i and m f are the initial and final percent masses and m u03c4 the percent mass at time u03c4 as they are recorded during a tg experiment the real time and temperature are simply related through the constant heating rate t t 0 u03b2 u03c4 assuming n 1 straight lines could be obtained plotting in u2212 in 1 u2212 u03b1 t 2 vs 1 t the value of the activation energy could be deduced from the slope of the straight lines obtained the first peak around 100 u00b0 c corresponds to the loss of the residual water the second peak at around 300 400 u00b0 c corresponds to the release of the volatile matter in the third stage a sharp peak is observed due to the char combustion brown coal without additives and untreated with h 2 so 4 u03b4e u2260 16 8 kj mol brown coal without additive but treated with h 2 so 4 u03b4e u2260 16 7 kj mol the use of the fe additive resulted in a decrease in the energy of activation by 5 5 kj mol which is 33 from the initial value of 16 8 kj mol additive testing on brown coal shows improved carbon burnout resulting in greater total weight loss the weight loss was achieved at lower temperature demonstrating the catalytic action of the additive linear regression data for fig4 6 are set out below in tables 1 3 while the present invention has been described with reference to specific examples it.