Effects of Pyrolysis Variables on the Product Yields During Pyrolysis of Palm Kernel Shells

Abstract

The effect of operating variables on the pyrolysis products when Palm Kernel Shell (PKS) was subjected to pyrolysis process was investigated in this work. 0.5 kg of dried sample of PKS was loaded into a steel retort, and the retort interior was rendered airtight. The retort was then placed into the furnace chamber and the PKS was pyrolysed at 300 o C between 10-30 minutes at 5 minutes interval. This was repeated for temperatures of 400, 500, 600 and 700 o C and in each case, the quantities of char, tar and pyro-gas produced were determined. Response surface methodology (RSM) was used to develop polynomial regression model and investigate the effect of changes in the level of pyrolysing temperature and duration on the product yields using Full Factorial Design (FFD). The contribution of pyrolysis temperature, duration and their squares (A, B, A 2 and B 2) to the model developed are significant. It was observed that the experimental data fitted better because of the Pred R-Squared of 0.9242 is in reasonable agreement with the Adj R-Squared of 0.9383. The agreement between the predicted and experimental values describe the accuracy of the model developed and can be used to navigate within the design space. The product yields minimum value of 0.89% was achieved at pyrolysis temperature and duration values of 300 o C and 10 min respectively. The optimum conversion product yields for dried PKS char, tar and gas at their respective pyrolysis conditions were 99 wt% char at 304 o C and 12 min., 35 wt% tar at 700 o C and 27 min., and 40 wt% gas at 700 o C and 30 min. The results obtained showed that PKS can be readily pyrolised to obtain optimum yield of bio fuels (gas, tar and char).