Environmental sustainability assessment of renewables-based propylene glycol at full industrial scale production

BACKGROUND Glycerol, a by-product from oleochemical or biodiesel production, can be used to produce renewables-based propylene glycol (PG). The environmental sustainability of PG was evaluated using life-cycle assessment. The effect of shifting from petrochemical to renewables-based PG was assessed by using data from an industrial scale renewables-based PG production plant. A contribution analysis was performed to identify the hotspots in the production process. The effects of implementing a sustainable sourcing strategy and producing steam/electricity by combined heat and power (CHP) were assessed. RESULTS A switch from petrochemical to renewables-based PG results in a reduction of the climate change impact between 40% and 60% kg CO2 eq. A shift of burden is found to agriculture-related indicators. For the biodiesel and oleochemical production route, respectively, 73% and 59% of the impact on climate change is related to feedstock production. By implementing two improvements, the emitted CO2 eq. for biodiesel PG could be reduced by 38%. CONCLUSIONS Switching from petrochemical to renewables-based PG has a clear environmental benefit for slowing climate change. However, the shift of burden towards agriculture-related indicators shows the need to ensure sustainable agricultural practices. Combining both on-site improvements and a more sustainable supply chain effectively decreases the environmental impact. (c) 2019 Society of Chemical Industry