Techno-economic assessment of polylactic acid and polybutylene succinate production in an integrated sugarcane biorefinery

Plastic waste pollution is a growing environmental concern due to the increased use of conventional plastics. This study investigates the techno-economics of biodegradable, bio-based plastics, i.e. polylactic acid (PLA) and polybutylene succinate (PBS), as potential substitutes for conventional plastics, to identify the most viable one to be produced in a biorefinery annexed to a typical sugar mill. Six potential biorefinery scenarios were simulated in Aspen Plus (R), in which PLA or PBS is derived from sugarcane molasses (1G scenarios), bagasse and harvesting residues (2G scenarios) or a mixture of molasses, bagasse, and harvesting residues (1G2G scenarios). The economic feasibility of the PLA and PBS scenarios was evaluated by means of the minimum selling prices (MSP) for an acceptable return on investment. The PLA scenarios showed lower MSPs than PBS with the 1G2G scenario having the lowest MSP (2965 US$ t(-1)), comparable to the commonly available PLA from corn grain (5140 US$ t(-1)). Polylactic acid benefited from lower process energy demands (5.5-5.8 MJ kg(-1) of biomass or sugars processed) compared to PBS (5.1-8.2 MJ kg(-1)), which plays a crucial role in an energy self-sufficient biorefinery. Furthermore, a 1G-biorefinery was identified producing a fully biobased PBS at an MSP of 2980 US$ t(-1) that is price competitive against fossil-derived PBS (2380 US$ t(-1)) and partially bio-derived PBS (4730 US$ t(-1)). To date, this was the first study to evaluate the detailed techno-economics of a fully biobased and biodegradable PBS biorefinery in an energy self-sufficient context, which was demonstrated to be cost-competitive against both partial bio-derived PBS and fully bio-derived PBS. (c) 2021 Society of Chemical Industry and John Wiley & Sons, Ltd