Optimization of pyrolysis process parameters for optimal high heating value of biochar produced from rice straw

The harvest of rice leaves abundant biowaste and its utilization is being researched. Hence, this paper targets the conversion of rice straw into biochar. In this study, the vacuum-assisted intermediate pyrolysis process is used to convert the rice straw biowaste into biochar, which can be used as a fuel. The produced biochar is studied for the biochar yield and energy yield. It is further analyzed for the high heating value (HHV). This experimental investigation optimizes the processing parameters such as time and temperature to obtain the optimal HHV. The response of HHV is maximized using response surface modeling (RSM) based on a central composite design (CCD) matrix. This technique systematically investigated the influence of continuous parameters on the dependent variable. As a result, the time and temperature and their interaction have the most significant effect on the HHV of the biochar obtained from two different amounts of feedstocks. The optimal response obtained for HHV1 is 21.45 MJ/kg at time 47 min and temperature 397 degrees C, whereas HHV2 is 19.43 MJ/kg at time 51 min and temperature 405 degrees C. The Fourier transform infrared (FTIR) analysis is further used to characterize the biochar obtained at optimized parameters.