Productions of phenolic rich bio-oil using waste chilli stem biomass by catalytic pyrolysis: Evaluation of reaction parameters on products distributions

In this study, catalytic pyrolysis of chilli stem (CS) were investigated in a fixed-bed reactor under N2 environment at reaction temperature of 350–500 °C in the presence of Ni–Ca/SiO2 catalyst systems. Ni–Ca/SiO2 catalysts were synthesized, characterized and evaluated for the oxygen transfer. The catalytic pyrolysis of biomass with catalysts (Ni/SiO2, Ca/SiO2, Ni–Ca/SiO2) was studied to identify the selective deoxygenation. Maximum bio-oil yield (45.2 wt%) was found with the Ni–Ca/SiO2 catalyst compared to the non-catalytic (34.8 wt%) and other catalytic reaction (35.6, 37.4 and 35.1 wt% for SiO2, Ca/SiO2 and Ni/SiO2 catalysts). With the addition of Ni/SiO2 and Ni–Ca/SiO2 catalyst, the oxygen was significantly removed in the form of CO2. In addition, the carbon and hydrogen content with Ni–Ca/SiO2 catalyst was higher than that of raw biomass. It also effectively improved the phenolics compounds in bio-oil with the addition of Ni–Ca/SiO2 catalyst during the pyrolysis process. It was found that the addition of Ca remarkable promoted the catalytic activity of Ni catalyst. It can be seen high catalytic activity and deoxygenation in Ni–Ca/SiO2 catalyst systems. •Catalytic pyrolysis of Chilli stem was investigated.•Maximum bio-oil (45.2 wt%) was obtained with Ni–Ca/SiO2 catalytic pyrolysis.•Phenolic rich bio-oil products were found with Ni–Ca/SiO2 catalyst.•Catalytic pyrolysis produced higher heating bio-oil 27.6 MJ/kg.