Optimization of process parameters for microwave pyrolysis of oil palm fiber (OPF) for hydrogen and biochar production

Abstract

Response surface methodology (RSM) based on central composite design (CCD) is used to investigate the optimized experimental conditions for maximum H2 and biochar yields from microwave pyrolysis of OPF. Input parameters (temperature, microwave power and N2 flow rate) have been coded which suggest a complete summary of experimental design with a set of experiment for the two responses of H2 and biochar. Quadratic model has been found fit for the optimization. This method significantly reduces the number of the experiments (Full factorial experiments). Actual vs. predicted plots clearly imply that experimental values are well in agreement with the predicted values for both H2 and biochar yield. The perturbation plots indicate that H2 and biochar yields are more sensitive for N2 flow rate and temperature respectively. The software suggested three optimized experimental conditions for maximum H2 yield, maximum biochar yield and for both maximum H2 and biochar yields together. The software results were further validated by conducting relevant experiments. The error was less than 10%, suggesting that the software predictions are quite reliable. Proximate and ultimate analysis of the optimized biochars have showed a big percentage of carbon contents (More than 60wt.%) and high heating value. SEM and BET analysis show some pores in the biochars which are effective for soil improvements.