Techno‐economic analysis of sugar production from lignocellulosic biomass with utilization of hemicellulose and lignin for high‐value co‐products

Sugar derived from lignocellulosic biomass is an important intermediate product, often used for the production of biofuels and value-added chemicals. It is therefore essential to understand and reduce the production costs of sugar derived from lignocellulosic biomass. This study evaluates the economic feasibility of a biorefinery producing sugar from lignocellulosic biomass using a combination of autohydrolysis and mechanical refining pretreatment. This biorefinery is self-sufficient in energy, producing excess electricity for sale. The minimum sugar selling price (MSSP) that achieves a zero net present value is $446/metric ton. The possibility of using the two main by-products, dissolved hemicellulose and lignin, for the production of high-value products, xylitol and polyol, is also evaluated. When dissolved hemicellulose is used for xylitol production, the MSSP decreases to $347/metric ton. When lignin is liquefied to produce polyol, the MSSP is further reduced to $342/metric ton. External energy (natural gas) must be purchased if xylitol and polyol are produced. An analysis of capital and operating costs reveals that, although the production of xylitol and polyol incurs additional capital investment, their correspondingly high values outweigh the additional capital costs. Sensitivity analysis results indicate that efficient recovery and recycling of expensive chemicals like acetone and glycerol are key to the success of the biorefinery. Yields of xylitol and polyol also have strong impacts on the process economics. (c) 2020 Society of Industrial Chemistry and John Wiley & Sons Ltd