Tassia L. Junqueira

Integrated versus stand-alone second generation ethanol production from sugarcane bagasse and trash.

Ethanol production from lignocellulosic materials is often conceived considering independent, stand-alone production plants; in the Brazilian scenario, where part of the potential feedstock (sugarcane bagasse) for second generation ethanol production is already available at conventional first generation production plants, an integrated first and second generation production process seems to be the most obvious option. In this study stand-alone second generation ethanol production from surplus sugarcane bagasse and trash is compared with conventional first generation ethanol production from sugarcane and with integrated first and second generation; simulations were developed to represent the different technological scenarios, which provided data for economic and environmental analysis. Results show that the integrated first and second generation ethanol production process from sugarcane leads to better economic results when compared with the stand-alone plant, especially when advanced hydrolysis technologies and pentoses fermentation are included.

Butanol production in a first-generation Brazilian sugarcane biorefinery: Technical aspects and economics of greenfield projects

The techno-economics of greenfield projects of a first-generation sugarcane biorefinery aimed to produce ethanol, sugar, power, and n-butanol was conducted taking into account different butanol fermentation technologies (regular microorganism and mutant strain with improved butanol yield) and market scenarios (chemicals and automotive fuel). The complete sugarcane biorefinery with the batch acetone-butanol-ethanol (ABE) fermentation process was simulated using Aspen Plus®. The biorefinery was designed to process 2 million tonne sugarcane per year and utilize 25%, 50%, and 25% of the available sugarcane juice to produce sugar, ethanol, and butanol, respectively. The investment on a biorefinery with butanol production showed to be more attractive [14.8% IRR, P(IRR>12%)=0.99] than the conventional 50:50 (ethanol:sugar) annexed plant [13.3% IRR, P(IRR>12%)=0.80] only in the case butanol is produced by an improved microorganism and traded as a chemical.

Utilization of pentoses from sugarcane biomass: Techno-economics of biogas vs. butanol production

This paper presents the techno-economics of greenfield projects of an integrated first and second-generation sugarcane biorefinery in which pentose sugars obtained from sugarcane biomass are used either for biogas (consumed internally in the power boiler) or n-butanol production via the ABE batch fermentation process. The complete sugarcane biorefinery was simulated using Aspen Plus®. Although the pentoses stream available in the sugarcane biorefinery gives room for a relatively small biobutanol plant (7.1-12 thousand tonnes per year), the introduction of butanol and acetone to the product portfolio of the biorefinery increased and diversified its revenues. Whereas the IRR of the investment on a biorefinery with biogas production is 11.3%, IRR varied between 13.1% and 15.2% in the butanol production option, depending on technology (regular or engineered microorganism with improved butanol yield and pentoses conversion) and target market (chemicals or automotive fuels). Additional discussions include the effects of energy-efficient technologies for butanol processing on the profitability of the biorefinery.

Anhydrous bioethanol production using bioglycerol – simulation of extractive distillation processes

Bioethanol has been increasingly used as fuel in the anhydrous form, mixed with gasoline. In this work, two configurations of the extractive distillation process using bioglycerol as a solvent for anhydrous bioethanol production were investigated. Simulations results show that bioglycerol is a suitable agent for the separation of ethanol-water mixtures, with low energy consumption on the column reboilers and the production of high quality anhydrous bioethanol.

Techno-economic analysis and climate change impacts of sugarcane biorefineries considering different time horizons

BackgroundEthanol production from lignocellulosic feedstocks (also known as 2nd generation or 2G ethanol process) presents a great potential for reducing both ethanol production costs and climate change impacts since agricultural residues and dedicated energy crops are used as feedstock. This study aimed at the quantification of the economic and environmental impacts considering the current and future scenarios of sugarcane biorefineries taking into account not only the improvements of the industrial process but also of biomass production systems. Technology assumptions and scenarios setup were supported by main companies and stakeholders, involved in the lignocellulosic ethanol production chain from Brazil and abroad. For instance, scenarios considered higher efficiencies and lower residence times for pretreatment, enzymatic hydrolysis, and fermentation (including pentoses fermentation); higher sugarcane yields; and introduction of energy cane (a high fiber variety of cane).ResultsEthanol production costs were estimated for different time horizons. In the short term, 2G ethanol presents higher costs compared to 1st generation (1G) ethanol. However, in the long term, 2G ethanol is more competitive, presenting remarkable lower production cost than 1G ethanol, even considering some uncertainties regarding technology and market aspects. In addition, environmental assessment showed that both 1G (in the medium and long term) and 2G ethanol can reduce climate change impacts by more than 80% when compared to gasoline.ConclusionsThis work showed the great potential of 2G ethanol production in terms of economic and environmental aspects. These results can support new research programs and public policies designed to stimulate both production and consumption of 2G ethanol in Brazil, accelerating the path along the learning curve. Some examples of mechanisms include: incentives to the establishment of local equipment and enzyme suppliers; and specific funding programs for the development and use of energy cane.

Simulation of the Azeotropic Distillation for Anhydrous Bioethanol Production: Study on the Formation of a Second Liquid Phase

Abstract Bioethanol is produced from fermentation of sugars, what produces a dilute solution (around 10 wt% ethanol). Because water and ethanol form an azeotrope with concentration of 95.6 wt% ethanol at 1 atm, an alternative separation process such as azeotropic distillation must be employed to produce anhydrous bioethanol, which can be used in a mixture with gasoline. In this work, simulations of three different configurations of the azeotropic distillation process with cyclohexane for anhydrous bioethanol production were carried out using software Aspen Plus. Process parameters were optimized in order to decrease the formation of a second liquid phase inside the column. Ethanol and entrainer losses as well as energy demand were evaluated.

Long-Term Prospects for the Environmental Profile of Advanced Sugar Cane Ethanol

This work assessed the environmental impacts of the production and use of 1 MJ of hydrous ethanol (E100) in Brazil in prospective scenarios (2020-2030), considering the deployment of technologies currently under development and better agricultural practices. The life cycle assessment technique was employed using the CML method for the life cycle impact assessment and the Monte Carlo method for the uncertainty analysis. Abiotic depletion, global warming, human toxicity, ecotoxicity, photochemical oxidation, acidification, and eutrophication were the environmental impacts categories analyzed. Results indicate that the proposed improvements (especially no-til farming-scenarios s2 and s4) would lead to environmental benefits in prospective scenarios compared to the current ethanol production (scenario s0). Combined first and second generation ethanol production (scenarios s3 and s4) would require less agricultural land but would not perform better than the projected first generation ethanol, although the uncertainties are relatively high. The best use of 1 ha of sugar cane was also assessed, considering the displacement of the conventional products by ethanol and electricity. No-til practices combined with the production of first generation ethanol and electricity (scenario s2) would lead to the largest mitigation effects for global warming and abiotic depletion. For the remaining categories, emissions would not be mitigated with the utilization of the sugar cane products. However, this conclusion is sensitive to the displaced electricity sources.

Economic and environmental assessment of integrated 1st and 2nd generation sugarcane bioethanol production evaluating different 2nd generation process alternatives

Abstract Integration of second generation ethanol production from lignocellulosic material with first generation ethanol production from sugarcane juice may foster its environmental and economic feasibility. Since sugarcane bagasse and trash may be used as energy feedstock in bioethanol production process, the amount of surplus lignocellulosic material that could be used for second generation bioethanol production is related to the processes energy consumption. In this work different process configurations for second generation were evaluated through simulation with Aspen Plus. Bearing this in mind, economic and environmental analyses are based on simulation results. Evaluated process alternatives presented different impact trends on sustainability indicators, indicating also that they may lead to higher ethanol output, higher economic returns and lower environmental impacts, pointing out that improvements are required in the ethanol production process for a sustainable energy future.

Simulation and optimization of the continuous vacuum extractive fermentation for bioethanol production and evaluation of the influence on distillation process

Abstract In this work, the use of a vacuum extractive fermentation reactor, which allows the production of wine with higher ethanol concentration, as well as its effects on the distillation stage, were studied for bioethanol production. Energy consumption was evaluated and compared to the conventional process, showing that the proposed configuration provides a significant reduction in energy consumption, so it seems an interesting option for process intensification.

Use of VSB to Plan Research Programs and Public Policies

The VSB comprises a useful framework for assessing research programs, and define and evaluate the effects of public policies. This chapter describes two cases regarding the use of VSB for R&D evaluation—enzyme development and use of energy cane as a new feedstock for sugarcane biorefinery—and a public policy formulation for biogas production and use in the biorefinery context.