Isolation of lignocellulosic components from corncob residue through industrially viable cleaner processes and their techno-economic analysis

Several lignin isolation and thermochemical pretreatment methods are practiced industrially to replace the usage of fossil fuels. In the present study, corncob residue after furfural extraction was sourced from a local industry for the recovery of lignin. Alkali and organosolv treatment methods are the two processes tried and the effect of temperature, concentration, and reaction time on the yield is recorded. Process optimization has been carried out using response surface methodology (RSM) and the optimized process conditions were derived. A quadratic model was developed based on the experimental data obtained. The obtained lignin is characterized by Fourier-transform infrared red (FTIR) spectroscopy and themogravimetric analysis (TGA) and found to have properties matching closely with authentic lignin. Furthermore, it was observed that the purity of lignin obtained from both these processes was >93% and a yield of greater than 95%. The focus of the present work was also to minimize the usage of water and reuse the water through NaCl precipitation process. A process flow diagram for the optimized conditions and process is developed and techno-economic analysis (TEA) is carried out. The annual revenue generated and the annual profits are listed to arrive at the payout period of 0.96 year for alkali process in comparison to that of organosolv process.