Sugarcane bagasse valorization to xylitol: Techno‐economic and life cycle assessment

Abstract

A detailed techno-economic analysis and life cycle assessment (LCA) of a novel bio-refinery that produces xylitol from sugarcane bagasse are provided. The proposed process includes dilute acid pretreatment in pressurized conditions followed by fermentation (upstream section). The fermentation broth is then sent for separation and purification to the downstream section. Calculations are performed for a plant with 4 t/h of dry bagasse throughput. With a fermentation yield of 0.54 g xylitol per g of xylose, the plant produced 437.4 kg/h of xylitol. Upstream data are adapted from experimental studies, while ASPEN PLUS ® flowsheet simulation is used to obtain data for the downstream section. The xylitol production facility is assumed to be annexed to an existing sugar mill in India. The total utility requirement in the process is reduced using heat integration strategies. Cradle-to-gate scope is considered for the LCA and 1 kg of xylitol is taken as the functional unit. The product cost of xylitol is calculated to be 230 INR/kg (US$3.17/kg). For a 4 year payback period, the selling price of xylitol must be 450 INR/kg (US$6.2/ kg). The fermentation and pretreatment sections are the major components of the product cost. The LCA results show that the life cycle greenhouse gas emissions are 2.759 kg CO 2 eq. per kg xylitol. The electricity requirement within the plant is identified as the major source of greenhouse gas emissions, and reduction of fermentation duration is identified as a key factor. The results identify opportunities to improve the process from an economic as well as an environmental standpoint.

Integrated Sugar Industry Complex in India: Comparison of Different Potential Configurations

“…Likewise, 5.51 kg of CO 2 equiv can be avoided upon displacement of 1 kg of fossil-CNG by Bio-CNG as a transportation fuel in India for configuration 2 (Munagala et al), which reduced the net GHG to 47.81 kg of CO 2 equiv/tonne of cane for configuration 2. Similarly, 1 kg of lactic acid, succinic acid, and xylitol produced from configurations 4, 5, and 6 on displacing the fossil counterparts resulted in avoided emissions of 4.5, 1.9, and 3.839 kg CO 2 equiv, respectively. ,, Consequently, configuration 4 (lactic acid) with the highest impacts earlier reduced drastically to the second lowest impact route upon considering avoided emissions. Thus, significant GHG offset due to avoided fossil–lactic acid emissions substantially benefitted configuration 4.…”

“…Similarly, 1 kg of lactic acid, succinic acid, and xylitol produced from configurations 4, 5, and 6 on displacing the fossil counterparts resulted in avoided emissions of 4.5, 1.9, and 3.839 kg CO 2 equiv, respectively. 30,21,22 Consequently, configuration 4 (lactic acid) with the highest impacts earlier reduced drastically to the second lowest impact route upon considering avoided emissions. Thus, significant GHG offset due to avoided fossil−lactic acid emissions substantially benefitted configuration 4.…”

Techno-Economic Analysis of 2,3-Butanediol Production from Sugarcane Bagasse

“…The BDO production process from SCB-derived xylose was reported in our previous publications. , A simplified scheme of the proposed plant is depicted in Figure . Analysis assumes that the moisture content in the feedstock was 35%, and the chemical composition of dry SCB was as follows: cellulose 48.5%, hemicellulose 21%, lignin 18%, ash 3.4%, and other solids 9.1% . The process starts with size reduction of SCB, followed by dilute acid pre-treatment using sulfuric acid (5% w/w) and subsequent steam explosion.…”

“…We also considered 10% conversion of cellulose to glucose and 1% conversion of xylose obtained from hemicellulose to furfural. In all these reactions, we have kept the final xylose concentration and mass flow rate consistent with the pre-treatment data obtained from Nova Pangaea Technology Limited, who have developed and optimized the pre-treatment process for treating 4 dry MT/h of SCB . The output from pre-treatment at high pressure is sent to a flash vessel and then to a washer unit where wastewater containing minor impurities and organic acids are separated.…”

“…Techno-economic analysis (TEA) is an effective and standard methodology to evaluate the economic feasibility of a product or process. TEA has been previously reported for utilizing SCB as a feedstock in the production of liquid biofuels, lactic acid, succinic acid, bioethanol, furfural, biosurfactant, xylitol, activated carbons, or simply for energy generation. − Munagala et al (2021) described the overall sustainability of SCB valorization to produce lactic acid based on the life cycle and TEA of biorefinery annexed to a sugar mill . Shaji et al (2021) also focused on utilizing SCB and performed a detailed sustainability assessment of a biorefinery producing succinic acid from SCB .…”