VALORISATION OF RICE HUSK WASTE AND BUBBLE WRAP PLASTIC WASTE THROUGH CO-TORREFACTION TO PRODUCE BIOCHAR

• Main Author: Gonzaga Holy Prajitna, Aloysius
• Format: Final Project
• Language: Indonesia
• Subjects: Teknik saniter dan perkotaan; teknik perlindungan lingkungan
• Online Access: https://digilib.itb.ac.id/gdl/view/66970
• Institution: Institut Teknologi Bandung

Rice husk is abundantly available agriculture byproduct in Indonesia with estimated generation of 11.10-13.82 Mt in 2021, which is mostly openly burnt or discarded into the agricultural land which causes negative environmental impact. Rice husk is a potential source of renewable biomass energy that is yet to be exploited. Torrefaction is a thermochemical conversion process done onto lignocellulosic biomass at 200-300oC which aims to increase fuel characteristics of biomass through biochar formation. The biochar sees increased energy density, HHV, and fixed carbon content, all while decreasing volatile content. Torrefied rice husk biochar has increased, calorific value (HHV) to 15.04 MJ/kg, fixed carbon content of 17.94%, all while decreasing the volatile content to 42.94%. Despite the increase in fuel characteristics compared to raw rice husk, the torrefaction process created a rather high mass loss, yielding only 54% of its original mass. Bubble wrap, plastic mostly composed of low density polyethylene (LDPE) polymer is also generated in high amounts. Co-torrefaction of rice husk and bubble wrap optimises char production, which increases mass yield to 72% at equal parts (50:50) of rice husk and bubble wrap plastic mass fraction (RH50), while also increasing energy yield and density to 81% and 114% respectively. Fixed carbon content of RH50 is decreased to 6.51%, HHV increased to 20.13MJ/kg, and volatile content increased to 78.68%. The biochar fuel properties increase slowly as the weight percentage of bubble wrap increases. The change in fuel properties is mostly caused by the limited chemical changes in bubble wrap plastic properties. Other factor could also include secondary char formation due to char matrix pore blockage caused by the molten plastic fraction within the feedstock, which can be determined as a synergistic effect in yield and fuel properties optimisation.