THE ROLE OF METAL-SALTS IN THE PYROLYSIS OF BIOMASS

Biomass in the form of cellulose was pyrolysed in a thermogravimetric analyser and static batch reactor in the presence of several metal salts and increasing concentrations of the metal salt. The thermogravimetric analyser was used to study the devolatilisation of the cellulose and formation of char and to derive the kinetic parameters, pre-exponential factor and activation energy in the presence of the metal salts. The static batch reactor enabled the determination of product yield of the char, gas and liquid and the composition of the gas in relation to the type of metal salt and concentration. The results showed that even low concentrations of metal salt significantly affect the thermal degradation of cellulose and the production of residual char. Increasing the metal salt concentration resulted in a lowering of the temperature where the main pyrolysis occurred and an increase in the number of distinct areas of weight loss. The static batch reactor results showed that the added metal salts increased the concentration of H-2 in all cases, however, CuSO4, NaCl and FeSO4 produced lower concentrations of hydrocarbons, CO and CO2 compared to untreated cellulose. The mechanism of the effect of added metal salts is discussed.