Papers by Tassia Lopes Junqueira
Orientadores: Rubens Maciel Filho, Maria Regina Wolf MacielDissertação (mestrado) - Universidade ... more Orientadores: Rubens Maciel Filho, Maria Regina Wolf MacielDissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia QuimicaResumo: No Brasil, o bioetanol é usado para substituir a gasolina, compondo uma porcentagem desta ou sendo usado como combustível alternativo. Esta tendência de substituição dos combustíveis fósseis vem se fortalecendo em âmbito global, sendo necessárias, portanto, alternativas e propostas que viabilizem o aumento da produção de forma economicamente e ambientalmente sustentável. Neste contexto, a otimização energética do processo de separação do bioetanol visa à disponibilização de bagaço de cana-de-açúcar, usado como combustível na geração de vapor de processo, para a produção de bioetanol através do processo de hidrólise. Para tanto, inovações ao processo são essenciais e melhoramento na representação de modelos torna-se necessário para estudos e avaliações. Neste trabalho, simulações da etapa de destilação para a produção de álcool ...
As usinas de cana-de-acucar encaixam-se no conceito de biorrefinaria, uma vez que produzem etanol... more As usinas de cana-de-acucar encaixam-se no conceito de biorrefinaria, uma vez que produzem etanol, acucar e eletricidade, entre outros produtos. A producao de etanol de 1a geracao (1G), a partir do caldo de cana-de-acucar, e um processo bem estabelecido, enquanto a producao de etanol a partir de materiais lignocelulosicos, denominado processo de 2a geracao (2G), tem recebido atencao especial nas ultimas decadas. No Brasil, bagaco e palha sao as materias-primas de maior potencial para a producao de etanol 2G devido a sua disponibilidade e relativo baixo custo, no entanto o processo nao esta consolidado ate o momento. O presente estudo teve por objetivo estudar a integracao de diferentes tecnologias ao processo de producao de etanol, considerando as tecnologias 1G e 2G, a fim de avaliar os impactos na viabilidade tecnico-economica das biorrefinarias de cana-de-acucar. Resultados mostraram que a diversificacao dos produtos, atraves da producao de acucar, eletricidade e biogas, bem como a flexibilidade na producao melhoram a viabilidade tecnico-economica e diminuem a suscetibilidade as oscilacoes de mercado, aumentando a estabilidade dos negocios. Para a producao de etanol 2G, os impactos das condicoes operacionais da hidrolise enzimatica e caracteristicas das enzimas no processo integrado de producao de etanol 1G2G foram avaliados atraves da formulacao de um modelo matematico e analise estatistica. Visando a reducao do custo de producao do etanol, as melhores condicoes operacionais foram determinadas e mostraram-se muito sensiveis ao preco de enzimas. A extensao do periodo de operacao das biorrefinarias de cana-de-acucar, que e usualmente de 6 a 8 meses por ano, permite reduzir a contribuicao do investimento no custo de producao de etanol. O processamento de sorgo sacarino durante a entressafra de cana-de-acucar apresentou expressivo potencial para incrementar a producao de etanol e eletricidade, bem como melhorar a viabilidade economica. A integracao de uma planta 2G processando o ano todo resultou em uma alternativa promissora, mas com alto investimento quando comparada as demais alternativas. A abordagem apresentada nesta tese pode ser utilizada para avaliar outras rotas e tecnologias, identificando gargalos tecnologicos e guiando a pesquisa a fim de aumentar a viabilidade do processo. Abstract
Após um longo período de desenvolvimento tecnológico em nível mundial, o etanol celulósico ou de ... more Após um longo período de desenvolvimento tecnológico em nível mundial, o etanol celulósico ou de segunda geração (E2G) atingiu o estágio de plantas comerciais. O Brasil, por conta dos projetos fomentados pelo Plano Conjunto BNDES-Finep de Apoio à Inovação Tecnológica Industrial dos Setores Sucroenergético e Sucroquímico (PAISS), tem atualmente uma capacidade instalada de produção de E2G de cerca de 140 milhões de litros
In this work, alternative configurations to fermentation and distillation process for hydrous eth... more In this work, alternative configurations to fermentation and distillation process for hydrous ethanol production were proposed and evaluated. Three configurations were analyzed: conventional fermentation and distillation (CFCD), vacuum extractive fermentation coupled with double effect distillation (VFDD) and vacuum extractive fermentation coupled with conventional distillation (VFCD). The VFDD configuration provided a significant reduction on energy consumption; however, ethanol losses were considerably high. Regarding ethanol recovery on the distillation process, VFCD configuration achieved the highest value (95.5%) among the studied processes.
Computer Aided Chemical Engineering, 2009
Bioethanol is produced from fermentation of sugars, what produces a dilute solution (around 10 wt... more 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
Computer Aided Chemical Engineering, 2009
Most models available for simulation of multicomponent separation processes are based on the idea... more Most models available for simulation of multicomponent separation processes are based on the idealized concept of equilibrium or theoretical stages. However, accuracy of the predictions can be highly enhanced if a nonequilibrium stage model is taken into account. In this work, hydrous bioethanol production process was simulated using Aspen Plus® considering three calculation methods: equilibrium, equilibrium with constant plate efficiency
Computer Aided Chemical Engineering, 2009
Bioethanol has been increasingly used as fuel in the anhydrous form, mixed with gasoline. In this... more 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 ...
Computer Aided Chemical Engineering, 2009
Process simulation was used to analyze bioethanol distillation process, which requires a large am... more Process simulation was used to analyze bioethanol distillation process, which requires a large amount of thermal energy. As it is shown in this study, in the ethanol production process the fermentation stage has a significant impact on energy consumption in the purification step. Thus, alternative configurations in the fermentation and distillation processes were proposed and evaluated. The results showed that
Computer Aided Chemical Engineering, 2009
In this work, the use of a vacuum extractive fermentation reactor, which allows the production of... more 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
Separation Science and Technology, 2012
In view of the increasing environmental concern, the use of renewable and less pollutant energy s... more In view of the increasing environmental concern, the use of renewable and less pollutant energy sources has been encouraged. In this context, bioethanol has been used as fuel in the anhydrous form, blended with gasoline. In this work, simulations of the extractive distillation process in anhydrous bioethanol production were carried out in Aspen Plus® using nonequilibrium stage model and equilibrium
Chemical Engineering Research and Design, 2013
Sugarcane bagasse and trash are used as fuels in cogeneration systems for bioethanol production, ... more Sugarcane bagasse and trash are used as fuels in cogeneration systems for bioethanol production, supplying steam and electricity, but may also be used as feedstock for second generation ethanol. The amount of surplus lignocellulosic material used as feedstock depends on the energy consumption of the production process; residues of the pretreatment and hydrolysis operations (residual cellulose, lignin and eventually biogas from pentoses biodigestion) may be used as fuels and increase the amount of lignocellulosic material available as feedstock in hydrolysis. The configuration of the cogeneration system (boiler pressure, lignocellulosic material consumption and steam production, turbines efficiencies, among others) has a significant impact on consumption of fuel and electricity output; in the integrated first and second generation, it also affects overall ethanol production. Simulations of the integrated first and second generation ethanol production processes were carried out using Aspen Plus, comparing different configurations of the cogeneration systems and pentoses use (biodigestion and fermentation). Economic analysis shows that electricity sale can benefit second generation ethanol, even in relatively small amounts. Environmental analysis shows that the integrated first and second generation process has higher environmental impacts in most of the categories evaluated than first generation.
Bioresource Technology, 2012
Clean Technologies and Environmental Policy, 2011
Page 1. ORIGINAL PAPER Environmental and economic assessment of sugarcane first generation bioref... more Page 1. ORIGINAL PAPER Environmental and economic assessment of sugarcane first generation biorefineries in Brazil Otávio Cavalett Tassia L. Junqueira Marina OS Dias Charles DF Jesus Paulo E. Mantelatto Marcelo ...
In this work, simulations of the complete separation process in anhydrous bioethanol production w... more In this work, simulations of the complete separation process in anhydrous bioethanol production were carried out in Aspen Plus ® . This process comprises distillation and rectification columns as well as an extractive column. Equilibrium stage model and Barros & Wolf efficiency correlations were used to perform the calculations. Efficiency profiles were obtained for all columns showing that efficiency values significantly vary along the columns. Influence of the introduction of efficiencies was evaluated through comparison with equilibrium stage model (ideal process). Results pointed out that energy requirements are not significantly higher when efficiencies are taken into account; however stream results and temperature profiles were quite different from each other. This reveals that is necessary to consider efficiency changes along the column if reliable predictions are to be made.
Industrial Crops and Products
Energy
Abstract Techno-economic analysis of first- and second-generation (1G2G) integrated sugarcane bio... more Abstract Techno-economic analysis of first- and second-generation (1G2G) integrated sugarcane biorefinery producing ethanol and electricity was performed, exploring the virtues and limitations of dilute acid pretreatment. Process variables such as solid content in the pretreatment reactor, enzymatic hydrolysis time, and the possibility of pentose fermentation were pondered using computational tools and simulation platforms to assess the impacts of the variables overall production chain. Previously published data reporting optimal pretreatment conditions applied to a leading sugarcane hybrid were considered in the simulation studies. Better economic returns were obtained using the lowest solids content in the pretreatment reactor, the shortest incubation time in the enzymatic hydrolysis step, as well as the use of the pentose stream to produce additional ethanol. Process profitability was mostly affected by sugarcane cost, followed by capital costs associated with investment, and input chemicals costs. Finally, this study indicates that the economic benefits do not only depend on achievement of high final product yields, but also on a set of industrial factors, demonstrating the suitability of process simulation to point out industrial bottlenecks deserving future research.
BioEnergy Research
Sugarcane straw has become available in large quantities in the field due to transition from manu... more Sugarcane straw has become available in large quantities in the field due to transition from manual to mechanical harvesting. Straw can be used as fuel for cogeneration systems of sugarcane mills to increase surplus electricity for commercialization. However, the exploitation of straw potential is still limited due to some challenges related to its agricultural recovery and industrial processing. The retrofit (additional installation) of existing sugarcane mills to process straw is an alternative to reduce investment and to allow a gradual utilization of this biomass. In this work, techno-economic and environmental assessment of straw recovery through bale system to increase electricity export was assessed. Two scenarios with straw recovery and processing were defined to take advantage of an existing cogeneration system, considering its operation in the season and off-season periods. An increase of up to 57% on surplus electricity was achieved. Both scenarios resulted in economically feasible alternatives. However, results were very sensitive to the variations on electricity prices and straw costs. In terms of environmental benefits, the bioelectricity presented a great potential to mitigate greenhouse gas emissions compared with natural gas-based electricity. The higher electricity surplus also affects the carbon intensity of ethanol, which can lead to indirect gains when the Brazilian program for biofuels incentive is implemented.
Applied Energy
Integrated biorefineries for year-round production of renewable jet fuel (RJF). • Assessment of t... more Integrated biorefineries for year-round production of renewable jet fuel (RJF). • Assessment of three RJF production routes with ASTM approval. • On-site H 2 production via water electrolysis with bioelectricity from sugarcane. • HEFA with highest RJF production potential, while FT with best economic indices. • RJF with > 70% reduction in greenhouse gas emissions in relation to fossil jet fuel.
Biotechnology for biofuels, 2017
Ethanol production from lignocellulosic feedstocks (also known as 2nd generation or 2G ethanol pr... more Ethanol 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). Ethanol producti...
Uploads
Papers by Tassia Lopes Junqueira