Biomass to levulinic acid: A techno-economic analysis and sustainability of biorefinery processes in Southeast Asia

Abstract

Aligned with Singapore's commitment to sustainable development and investment in renewable resources, cleaner energy and technology (Sustainable Singapore Blueprint), we report a techno-economic analysis of the biorefinery process in Southeast Asia. The considerations in this study provide an overview of the current and future challenges in the biomass-to-chemical processes with life-cycle thinking, linking the land used for agriculture and biomass to the levulinic acid production. 7-8 kg of lignocellulosic feedstock (glucan content 30-35 wt%) from agriculture residues empty fruit bunches (EFB) or rice straw (RS) can be processed to yield 1 kg of levulinic acid. Comparisons of both traditional and "green" alternative solvents and separation techniques for the chemical process were modelled and their relative energy profiles evaluated. Using 2-methyltetrahydrofuran (2-MeTHF) as the process solvent showed to approx. 20 fold less energy demand compared to methyl isobutyl ketone (MIBK) or approx. 180 fold less energy demand compared to direct distillation from aqueous stream. Greenhouse gases emissions of the major operations throughout the supply chain (energy and solvent use, transport, field emissions) were estimated and compared against the impact of deforestation to make space for agriculture purposes. A biorefinery process for the production of 20 ktonne/year of levulinic acid from two different types of lignocellulosic feedstock was hypothesized for different scenarios. In one scenario the chemical plant producing levulinic acid was located in Singapore whereas in other scenarios, its location was placed in a neighboring country, closer to the biomass source. Results from this study show the importance of feedstock choices, as well as the associated plant locations, in the quest for sustainability objectives.

Keywords: Biomass; Biorefinery model; Levulinic acid; Sustainability.