Mind the Pulp: Environmental and economic assessment of a sugar beet pulp biorefinery for biobased chemical production

Abstract

Sugar beet pulp, a byproduct from sugar beet refining, is used by farmers as fertilizer or sold as animal feed. Both options underestimate the potential of sugar beet pulp as a platform to produce specialty and bulky chemicals as a promising pathway for sustainable biochemicals – mind the pulp. This study proposes a biorefinery concept to produce food additives (pectin-derived oligosaccharides) and bulky chemicals (terephthalic acid). Since the biorefinery has a low technology readiness level (TRL = 1), it is relevant to evaluate the feasibility of this biorefinery concept to provide guidance (at an early stage) on the environmental and economic advantages and limitations. For this purpose, the life cycle assessment and techno-economic assessment frameworks are used to assess the environmental impact and economic performance of the biobased terephthalic acid, respectively. Moreover, environmental impacts are accounted for in economic terms using different monetary valuation methods (environmental prices, Ecovalue12, and Ecotax). The environmental impact of biobased terephthalic acid was higher in most impact categories than the fossil counterpart, depending on the selected allocation approach (mass vs economic). The economic feasibility of the proposed biorefinery is highly dependent on the pectin-derived oligosaccharides market price and the valorization of byproducts (humins and levulinic acid). The selection of the monetary valuation method is critical for monetizing environmental impacts when comparing biobased against fossil-based alternatives.