The present work assesses water and power consumption, ethanol production and CO2 emissions in order to evaluate the technical and economic feasibility of a high-scale sugarcane-based biorefinery and propose a scenario of full carbon and capture system, so the complex could become a sustainable carbon withdrawer from the atmosphere. This work is performed with the aid of professional software for a rigorous mass and energy balances simulation to achieve process data for plant technical and economic analysis. The combustion of sugarcane bagasse is the only source of energy of the plant, which provides steam for the distillery and generates electricity through cogeneration system. The ethanol production from sugars fermentation produces CO2 which, jointly with the CO2 from combustion, is released directly into the atmosphere contributing to global warming. Results demonstrate that for processing capacity of 1,000 t/h of sugarcane, the plant emits 0.7 tCO2 per ton of sugarcane, with net water consumption of 3,600 m3/h as make-up water to replace blowdown and evaporation losses in the cooling tower. The cogeneration system generates 320MW of net power for exportation as electricity. The economic analysis reveals a fixed capital investment of 910MMUSD and a net present value of 378MMUSD considering as revenues the ethanol produced and the electricity from cogeneration at an annual discount rate of 10%.
Biofilm-based wastewater treatment systems have become attractive due to their numerous advantages when compared to other suspended growth processes. However, the mathematical modeling of these reactors is relatively complex, since it has to consider a wide range of phenomena to accurately describe the process behavior. This work deals with the modeling of a two-stage MBBR system run in pre-denitrification mode for the removal of organic matter and nitrogen from wastewater. The model development took into account diffusive phenomena and kinetics in a homogeneous biofilm composed of different bacterial functional groups (namely heterotrophs and nitrifiers). The thickness of the biofilm was treated as a variable, given that detachment of adhered biomass took place. The suspended biomass fraction was also considered to remove the pollutants by means of Monod-type kinetics associated with the activated sludge model. The dynamic behavior of the components involved in the system and their spatial distribution in the biofilm obtained from simulated data showed good agreement with those reported in the literature, demonstrating the reproducibility of the model and encouraging future applications in full-scale MBBR plants.
Every day huge amounts of CO2 are released into the atmosphere by enterprises such as biorefineries. In this context, the present work proposes a plausible scenario where a large-scale sugarcane-based biorefinery capture over 92% of its CO2 emissions to be used as enhanced oil recovery (EOR) agent. The study is based on the integration of sugarcane crop–large-scale ethanol biorefinery–post-combustion capture–CO2 pipeline to EOR. As results, the plant obtained a CO2 recover of 91.3% from post-combustion capture, allowing export 5.29 MM tCO2/y. Basic revenues of this project came from ethanol production, electricity sales, and EOR. In addition, four scenarios were investigated considering incomes from the handling of the captured CO2. All scenarios were evaluated in terms of the use of 1 and 2 bbl/tCO2 for EOR, leading to the conclusion that long-term economic sustainability can be assured only for some scenarios and mainly above 2 bbl/tCO2.
RESUMO -A crescente demanda por energia impeliu a procura por novas fontes combustíveis, sendo o biodiesel um forte candidato. O Brasil possui uma variedade de oleaginosas com potencial para produção desse biocombustível, dentre elas o pinhão manso (Jatropha curcas L.). A extração do óleo dessa fonte gera uma torta rica em proteínas, carboidratos e lipídios, além de substâncias alergênicas e tóxicas que inviabilizam o seu uso, das quais, se incluem os ésteres de forbol. Diante desse entrave, o presente trabalho visa a degradação desses ésteres presentes no resíduo, através da inoculação do meio com fungos do gênero Aspergillus coletados de fontes distintas e capazes de crescer na torta. Os níveis dos ésteres de forbol presentes na torta foram verificados por Cromatografia Líquida de Alta Eficiência (CLAE) e teste ecotoxicológico com a bactéria Vibrio Fischeri. Pode-se constatar, pelas análises, uma diminuição dos níveis de ésteres de forbol em 55%, validando a eficácia do fungo na degradação dessas substâncias tóxicas.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.