techno-economic evaluation of 2nd generation bioethanol production from sugar cane bagasse and leaves integrated with the sugar-based ethanol process技术经济评价的第二代生物乙醇生产甘蔗蔗渣和树叶与糖基乙醇过程集成.pdfVIP

Macrelli et al. Biotechnology for Biofuels 2012, 5:22 /content/5/1/22 RESEARCH Open Access Techno-economic evaluation of 2nd generation bioethanol production from sugar cane bagasse and leaves integrated with the sugar-based ethanol process Stefano Macrelli1*, Johan Mogensen2 and Guido Zacchi1 Abstract Background: Bioethanol produced from the lignocellulosic fractions of sugar cane (bagasse and leaves), i.e. second generation (2G) bioethanol, has a promising market potential as an automotive fuel; however, the process is still under investigation on pilot/demonstration scale. From a process perspective, improvements in plant design can lower the production cost, providing better profitability and competitiveness if the conversion of the whole sugar cane is considered. Simulations have been performed with AspenPlus to investigate how process integration can affect the minimum ethanol selling price of this 2G process (MESP-2G), as well as improve the plant energy efficiency. This is achieved by integrating the well-established sucrose-to-bioethanol process with the enzymatic process for lignocellulosic materials. Bagasse and leaves were steam pretreated using H3PO4 as catalyst and separately hydrolysed and fermented. Results: The addition of a steam dryer, doubling of the enzyme dosage in enzymatic hydrolysis, including leaves as raw material in the 2G process, heat integration and the use of more energy-efficient equipment led to a 37% reduction in MESP-2G compared to the Base case. Modelling showed that the MESP for 2G ethanol was 0.97 US $/L, while in the future it could be reduced to 0.78 US$/L. In this case the overall production cost of 1G+2G ethanol would be about 0.40 US$/L with an output of 102 L/ton dry sugar cane including 50% leaves. Sensitivity analysis of the future scenario showed that a 50