Alternatives to produce biorefinery products from sugarcane bagasse

CLAUSER, N.; GUTIÉRREZ, S.; AREA M. C.; FELISSIA, F. E.; VALLEJOS M.E.

Espoo

Congreso; IX Iberoamerican Conference on Pulp and Paper Research, CIADICYP 2016; 2016

Aalto University, VTT, Åbo Akademi University, RIADICYP, PROVALOR

Production processes of bioproducts and biofuels from lignocellulosic biomass can be designed at different scales (micro, small, medium and large). Some advantages of small-scale biorefineries are the lower capital and logistics costs and the lower inversion risk than those in large-scale ones, in addition to the possibility of labor occupation in rural areas. In this work, different products from hemicelluloses and residual solids from the autohydrolysis of sugarcane bagasse were studied to find the most feasible scenario for a small-scale biorefinery. A model for autohydrolysis process was used to determine optimum treatment conditions (time and temperature) using GAMS Software (CONOPT solver). The subsequent processes were estimated and calculated based on experimental and updated bibliography. Finally, the total capital investment and IRR of each alternative were estimated. In scenario I, the evaluation included the production of xylose syrup, furfural and xylitol from hemicelluloses in the spent liquor of sugarcane bagasse autohydrolysis (15,000 ton per year of bagasse), as well as energy generation and medium-density fiberboard (MDF) production from the residual solid. Furfural with MDF production is also an alternative, but its IRR is lower. Despite of the high price of xylitol, the IRR of its production is relatively low due to the high investment cost. Scenario II was proposed to improve the feasibility of xylitol production. Liquid-solid ratio of the autohydrolysis treatment was reduced from 7:1 to 5.5:1 and the processing capacity was gradually increased up to 70,000 ton per year. A 23% reduction in energy consumption respect to the first scenario was verified. In these conditions, the production of xylitol and energy generation (EG), MDF, ethanol, or pellets from the residual solid was evaluated (Table 1). IRR improved slightly for xylitol production compared to scenario 1. Higher IRR is obtained for xylitol and EG production. Simultaneous production of xylitol and pellets is an interesting option when processing more than 20,000 ton per year of bagasse, whereas xylitol and ethanol production need to process 70,000 ton per year to be attractive.