FROM SUGAR MILL TO BIOREFINERY: DETERMINING THE GLOBAL WARMING POTENTIAL OF UPGRADING A CENTENARY FACTORY

BASED ON THE Life Cycle Assessment (LCA) a scoping review of the Global Warming Potential (GWP) of a multipurpose sugarcane biorefinery is presented. The Mossman sugar mill was assessed as an example for its potential transformation into a multi-product factory that adds value to all by-products and crop residues. A baseline scenario (S1) was established using the current production system, which produces sugarcane, sugar, molasses and electricity. The addition of industrial units to produce ethanol from molasses (S2), single-cell protein (SCP) from vinasse (S3), and bio-naphtha/electricity from crop residues (S4) completed the four scenarios under evaluation. Each system boundary was determined by the mass allocation method (MA). The accumulative GWP of sugarcane production was the highest, followed by sugar and bio-naphtha. As new industrial units were incorporated into the baseline scenario, S3 and S4 increased its total GWP by 30% and 86% respectively, while S2 was reduced by 1.7% compared with S1. An overall increase of GWP was observed by the change of a traditional sugar mill into a Biorefinery. However, the bio-naphtha, electricity and ethanol obtained with the design resulted in significantly less CO2 emissions than conventionally produced products. According to the studies surveyed most of the Green House Gases (GHG) emissions occurs during the field operations and not in the factory process. A detailed LCA study for the transformation of Mossman sugar mill into a Biorefinery should emphasise sugarcane production, transportation, and trash collection as the major sources of GHG.