Integrating first, second, and third generation biorefineries: Incorporating microalgae into the sugarcane biorefinery

In this study, it was discussed the possibilities of integrating biorefineries based on different generations of feedstock. The potential of using CO2-rich streams was analyzed for the cultivation and harvesting of microalgae biomass. In addition, the extraction of microalgae oil and its further transformation into biodiesel was considered. To achieve this, a techno-economic and environmental analysis of two biorefinery scenarios was performed based on sugarcane. Scenario 1 considers the joint production of sugar, ethanol, and electricity. Scenario 2 is an extension of Scenario 1 that also considers Chlorella sp. cultivation using CO2-rich streams derived from fermentation and cogeneration systems. After microalgae cultivation and harvesting, the extracted oil is used as the raw material to obtain biodiesel and glycerol as additional products, as well as electricity, ethanol, and sugar. Scenario 2 has the best performance from environmental and economic perspectives. For Scenario 2, it was determined that the economic net present value (NPV) is 183.94M.USD/y (lifetime of 10 years). The potential environmental impact (PEI) is 44.99 PEI/t of products, with the potential to reduce CO2 emissions by 395, compared with Scenario 1. (C) 2014 Elsevier Ltd. All rights reserved.