Papers by Alice Medeiros de Lima
A produção de etanol a partir de biomassa lignocelulósica tem sido amplamente estudada pois aumen... more A produção de etanol a partir de biomassa lignocelulósica tem sido amplamente estudada pois aumenta-se a produtividade de etanol por hectare de cana-deaçúcar plantada de forma a atender a crescente demanda por biocombustível. Entretanto, a utilização desta tecnologia encontra alguns entraves tecnológicos e econômicos como o alto custo das enzimas. Assim, este artigo faz uma revisão da viabilidade técnico-econômica da produção de etanol de segunda geração no Brasil e no mundo e aponta algumas perspectivas para o setor.
Chemical Engineering & Technology, 2021
Anais do XX Congresso Brasileiro de Engenharia Química, 2015
This paper presents the application of mass integration methodology to a sugarcane biorefinery, u... more This paper presents the application of mass integration methodology to a sugarcane biorefinery, using a modified flexible tolerance method (MFTM) for optimization. For environmental reasons, the targets for mass integration were water, emissions of carbon dioxide from the fermentation process, and vinasse. The MFTM presented good performance in optimization of the process configuration, with reductions of 29, 28, and 33% in the costs of fresh water supply, wastewater treatment, and vinasse fertirrigation (including the costs associated with vinasse concentration), respectively. In addition, emissions of CO 2 were avoided using algae farm technology for ethanol production, resulting in benefits to the environment as well as economic advantages including carbon credits and additional ethanol production.
Chinese Journal of Chemical Engineering, 2016
Abstract This paper proposes the use of the flexible tolerance method (FTM) modified with scaling... more Abstract This paper proposes the use of the flexible tolerance method (FTM) modified with scaling of variables and hybridized with different unconstrained optimization methods to solve real constrained optimization problems. The benchmark problems used to analyze the performance of the methods were taken from G-Suite functions. The original method (FTM) and other four proposed methods: (i) FTM with scaling of variables (FTMS), (ii) FTMS hybridized with BFGS (FTMS-BFGS), (iii) FTMS hybridized with modified Powell's method (FTMS-Powell) and (iv) FTMS hybridized with PSO (FTMS-PSO), were implemented. The success rates of the methods were 80%, 100%, 75%, 95% and 85%, for FTM, FTMS, FTMS-BFGS, FTMS-Powell and FTMS-PSO, respectively. Numerical experiments including real constrained problems indicated that FTMS gave the best performance, followed by FTMS-Powell and FTMS-PSO. Despite the inferior performance compared to FTMS and FTMS-Powell, the FTMS-PSO method presented some advantages since good different initial points could be obtained, which allow exploring different routes through the solution space and to escape from local optima. The proposed methods proved to be an effective way of improving the performance of the original FTM.
Chinese Journal of Chemical Engineering, 2017
Abstract This paper proposes the use of the flexible tolerance method (FTM) modified with adaptiv... more Abstract This paper proposes the use of the flexible tolerance method (FTM) modified with adaptive Nelder–Mead parameters and barrier to solve constrained optimization problems. The problems used to analyze the performance of the methods were taken from G-Suite functions, and the methods with the best performance were applied in mass integration problems. Four methods were proposed: (1) flexible tolerance method (FTM) using adaptive parameters (FTMA), (2) flexible tolerance method with scaling (FTMS) and with adaptive parameters (FTMAS), (3) FTMS including the barrier modification (MFTMS) and (4) MFTMS hybridized with PSO (MFTMS-PSO). The success rates of these methods were 100% (MFTMS), 85% (MFTMS-PSO), 40% (FTMAS) and 30% (FTMA). Numerical experiments indicated that the MFTMS could efficiently and reliably improve the accuracy of global optima. In mass integration, the method was able, from current process situation, to reach the optimum process configuration that includes integration issues, which was not possible using FTM in its standard formulation. The hybridization of FTMS with PSO (without barrier), FTMS-PSO, was also able to solve mass integration problems efficiently.
The ethylene production through catalytic dehydration of ethanol is a process that became stagnat... more The ethylene production through catalytic dehydration of ethanol is a process that became stagnated over the last decades due to viability and low costs of natural gas and naphtha. Nowadays ethylene production is usually done by cracking of hydrocarbons. However, the manufacture of ethylene through ethanol is getting more attention mainly because of environmental reasons. Thus, this work had as objectives to study the kinetics of ethylene production from ethanol using Al 2 O 3 and CeZrO 2 as catalysts to optimize reaction conditions and to analyze thermodynamically this system using the minimization of the Gibbs free energy using experimental values at standard state and using methods based in quantum chemistry. A design of experiment methodology was used to obtain kinetic data varying temperature, ethanol concentration in feed and residence time and the data was fitted to obtain response surfaces. The maximization of ethanol conversion and molar fraction of ethylene was done using non-linear optimization method generalized reduced gradient (GRG). Kinetic models proposed in this work were Power-Law type and others simple models based on Langmuir-Hinshelwood kinetic. Quantum computational calculations were performed using software Gaussian03 applying B3LYP/6-31G+ and G2 methods, while the others calculations used the free software Scilab. The CeZrO 2 catalyst was more selective for ethylene production than Al 2 O 3 , besides an expressive hydrogen formation. This could bring economic advantages, since this catalyst leads to products with high added value (C 2 H 4 and H 2), while alumina forms ethylene and a large quantity of water. Results of thermodynamic equilibrium state indicated that ethylene production through ethanol is highly favorable. The quantum method ab initio pos Hartree-Fock (G2) was more efficient that hybrid functional B3LYP in predicting chemical equilibrium in systems analyzed in this work, when compared with results obtained through experimental data on standard state. Effect of water addition in feed was studied and from a thermodynamical point of view, it may be said that the addition of small quantities of water does not affect expressively the equilibrium. This result can contribute to process economy as a whole, because an important part of costs in obtain ethylene through ethanol route is related to the need of using ethanol with high purity level.
In the last decades, ethylene production from ethanol was not largely investigated mainly because... more In the last decades, ethylene production from ethanol was not largely investigated mainly because of the viability and low costs of natural gas and naphtha. Nowadays, ethylene production is usually done by cracking of hydrocarbons. However, the manufacture of ethylene from ethanol is getting more attention mostly due to environmental reasons. The objective of this paper is to compare the equilibrium conversions and compositions of reactions systems involved in ethylene production from ethanol through computational simulations. The obtained results can help to find better operational conditions and elucidate preferential reaction routes involved in ethanol dehydration. Copyright © 2012 Praise Worthy Prize S.r.l. -All rights reserved. Nomenclature a 0 , a x , a c Empiric parameters [-] â Activity coefficient in mixture [-] C p Calorific capacity [J/mol K] E Energy [J/mol] ε 0 Total electronic energy [J/mol] Fugacity in mixture [bar] G Gibbs energy [J/mol] G corr Correction to the Gibb...
Resumo-O hidrogênio é uma das mais promissoras fontes de energia e pode ser produzido por diversa... more Resumo-O hidrogênio é uma das mais promissoras fontes de energia e pode ser produzido por diversas fontes renováveis e não-renováveis. Dentre as fontes renováveis, a fermentação é uma das mais promissoras alternativas de longo prazo para geração de hidrogênio a partir da biomassa. O objetivo deste trabalho foi analisar a viabilidade técnicoeconômica da produção de hidrogênio via fermentação. Os dados experimentais da produção de hidrogênio por microrganismos foram retirados da literatura. O sistema reacional foi simulado no software livre Scilab. As separações dos gases gerados no processo de fermentação anaeróbio foram estudadas considerando a captura do dióxido de carbono por monoetanolamina (MEA) em um absorvedor, com subseqüente seção de compressão de hidrogênio e dióxido de carbono, simulados no software livre Sim42. Foi feita uma análise econômica do processo, e considerando o atual estágio de maturação da tecnologia, o processo é economicamente pouco atrativo, resultando em um custo de produção de US$1,17 e um lucro de US$0,66/kg de hidrogênio produzido. Entretanto, com o amadurecer da tecnologia, o processo tornar-se-á uma alternativa viável. Este trabalho não teve o objetivo de esgotar as possibilidades e o estudo da produção de hidrogênio via fermentação, e sim mostrar através de um estudo preliminar, as principais diretrizes apontadas no cenário mundial no desenvolvimento desta tecnologia.
bdtd.ufu.br
Aos professores Adilson José de Assis e Carla Eponina Hori pela orientação. Às professoras Valéri... more Aos professores Adilson José de Assis e Carla Eponina Hori pela orientação. Às professoras Valéria Viana Murata e Lucienne Lobato Romanielo pelo apoio nas áreas de otimização e termodinâmica. Aos colegas de trabalho Sandra Dantas, Cícero Naves, Fabiano Almeida, Tatiana Franco e Cristiane Junqueira. À todos os meus amigos e aqueles que contribuíram direta ou indiretamente para a realização deste trabalho. À CAPES pelo fornecimento da bolsa de estudos.
Nonlinear Constrained Optimization With Flexible Tolerance Method: Improvement And Application In... more Nonlinear Constrained Optimization With Flexible Tolerance Method: Improvement And Application In Systems Synthesis Of Mass Integration This work is focused in constrained nonlinear optimization using the Flexible Tolerance Method (FTM) and in applying in systems synthesis of mass integration. Mass integration is a technique that allows an overall understanding of the mass flow within the process, and employs such knowledge in identification of performance improvements and optimization of the generation and mapping of species throughout the process. The mass integration is based on the fundamental principles of chemical engineering combined with system analysis using graphical and optimization tools. In this context, the direct method of optimization was used as the basis for improvements in order to make possible the application in process synthesis problems, especially mass integration. The Flexible Tolerance Method is a direct method of optimization that present some advantages a...
Uploads
Papers by Alice Medeiros de Lima