Kinetics of reactions involved in pyrolysis of cellulose has been modeled in terms of a three reaction model. In this model it is assumed that cellulose decomposes to tars, chars and gaseous products via three competitive first‐order reactions. Arrhenius parameters have been obtained to describe the rate constants of these reactions. The three reaction model predicts the weight loss data reasonably well. Product yields of tars, chars and gases predicted by the three reaction model are compared over the temperature range 250 to 360°C. In this communication a technique for analyzing experimental data of a solid state reaction is presented.

Arrhenius equation is popularly used to relate the change in the rate constant with temperature. The linearized form of Arrhenius equation has often been used to establish a relation between In ,4 and E for a series of related reactions. Occurrence of such a compensating behavior between In A and E has been widely reported in the literature. The validity of the compensation effect has been heatedly debated. Compensation effect can arise from computational artifact or can arise from various chemical factors. This depends entirely on the data set used to establish the compensation behavior. This article stresses the importance of statistical analysis and the use of simple Arrhenius plots to draw conclusions regarding the occurrence of compensation effect. With the help of a few examples, some checkpoints to draw conclusions regarding the occurrence of true or false compensation effect are suggested.

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At temperatures below 300°C, it has been shown that the pyrolysis of cellulose can be modeled in terms of a modified Kilzer‐Broido ((K‐B) Model. According to this model, cellulose decomposes via two competitive reactions, a dehydration reaction to form anhydrocellulose and a depolymerization reaction to form levoglucosan. Anhydrocellulose later decomposes to chars and gaseous products via two competitive reactions. Arrhenius parameters and a technique of estimating empirical constants from experimental data for the K‐B type reactions are presented. Comparison of the ability of the modified K‐B model and the three reaction model to predict weight loss, product yields and heat pretreated results are also made.

SynopsisThe isothermal pyrolysis of 100 mg samples of shredded newsprint, both untreated and 1% HCl washed, a t pressures below 1 torr has been examined between 260°C and 340°C. Pyrolysis occurs via a rapid initial reaction followed by a slower degradation that can he modeled as first order in remaining newsprint. The effect of a 1% HCl wash pretreatment is to increase the fractional tar yield by 40%, to decrease the gas yield by an equivalent amount, and to increase the extent of initial reaction. Arrhenius parameters have been obtained for rate constants describing both the initial and the slower degradation reactions for both untreated and acid washed newsprint.