Parametric Study of Rice Husk Pyrolysis via Process Simulation and Statistical Analysis

The transition from fossil fuels to alternative clean fuels is crucial to reducing greenhouse gas emissions and environmental degradation. Lignocellulosic biomass, such as rice husk, is considered a promising feedstock for alternative energy. This study evaluates the pyrolysis process of rice husk using Aspen Plus and Design Expert Software, incorporating analysis of variance (ANOVA). Rice husk was analyzed for its proximate, ultimate, and structural characteristics, and its thermogravimetric profile was assessed in an inert atmosphere at 10 °C/min using nitrogen. These characteristics were used as input for Aspen Plus simulations of the pyrolysis process, with variables such as temperature (350–500 °C) and nitrogen flow rate (1–10 kg/h) being studied both individually and collectively. ANOVA was performed using a central composite design with process variables at three levels (− 1, 0, + 1). The findings revealed that rice husk contains a significant amount of volatile matter (70.07 wt%) and has a calorific value of 15.22 MJ/kg. The sample’s composition was 40.15 wt% carbon, 5.98 wt% hydrogen, 0.41 wt% nitrogen, 0.78 wt% sulphur, and 52.68 wt% oxygen, with maximum decomposition occurring between 300 and 500 °C. Simulation results showed that higher pyrolysis temperatures increased pyrolytic oil production and decreased char, while higher nitrogen flow led to a slight increase in oil, a reduction in char, and an increase in pyrolytic gas. ANOVA indicated that temperature was most significant for oil and char yields, while nitrogen flow was significant for gas production. This study provides a systematic approach to understanding the combined effects of temperature and nitrogen flow on pyrolytic product distribution from rice husk.