Turning waste into value: eco‐efficient recovery of by‐products from biomass pretreatment in lignocellulosic biorefineries

Abstract

This original research contributes to enhancing the viability of biorefineries through recovering valuable by‐products from the liquid remaining after the biomass pretreatment by hot liquid water. A novel downstream processing method is developed for the recovery of acetic acid, formic acid, furfural and 5‐hydroxymethylfurfural (HMF) by enhanced distillation. The major challenge in this research is the processing of the highly diluted initial solution (>96 wt% water) and the thermodynamic limitations owing to possible formation of several azeotropes. This new process recovers 78.7% of the acetic acid (99.8 wt%), while the rest of it is recycled back to the biomass pretreatment step together with most of the separated water from the initial solution. Over 99.5% of formic acid, furfural and HMF is also recovered, at purities of 74.7, 98.0 and 100 wt%, respectively. Vapor recompression and heat integration are implemented to decrease the energy use. The results demonstrate a 77.4% decrease in total annual costs (from $3.44 to 0.78/kgproduct), a 75.0% reduction in minimum average selling price (from $3.50 to 0.87/kgproduct), an 81.1% reduction in energy requirements (from 77.41 to 14.66 kWthh/kgproduct) and an up to 99.7% decrease in CO2 emissions (from 11.17 to 0.03 kgCO2/kgproduct).

Process systems engineering perspectives on eco-efficient downstream processing of volatile biochemicals from fermentation

“…This significantly reduces the need for both external heating and cooling (Kiss and Infante Ferreira, 2016), resulting in decreased energy requirements (by about 60%-80%) and total recovery costs (by about 40%-80%). Furthermore, since CO 2 emissions are directly related to the energy usage, implementation of advance heat pump systems can significantly increase sustainability of the overall biochemical production process by lowering these emissions (reduction in CO 2 emissions for the recovery process by about 60%-75% in case electricity from fossil fuels has to be used, or even up to 100% if green electricity is available) (Janković et al, 2023a;Janković et al, 2023b).…”