Engenharia Química
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- ItemAplicação de um esquema de simulação e monitoramento via filtro de partículas na produção de etileno a partir do etanol.(Universidade Federal do Espírito Santo, 2017-02-13) Salardani, Luciana Souza Ferreira; Silva, Wellington Betencurte da; Dutra, Júlio Cesar Sampaio; Vieira, Fabrício Thiengo; Costa, José Mir Justino daThe present work discusses about the mathematical modeling, numerical simulation and the monitoring problem based on particle filter using single-point temperature measurements for the green ethylene production process from the catalytic dehydration of ethanol. With the scarcity of natural resources, the use of sustainable sources such as biomass instead of petroleum derivatives has been encouraged. For example, the ethylene required by the thermoplastics industry can be obtained from the catalytic dehydration of ethanol, which then generates green ethylene or bioethylene. Most of the published works about this process refer only to the synthesis of catalysts, mechanism and kinetics and no one were found considering the Bayesian estimation tool. Thus, the main contribution of this work is the proposal of an estimation scheme composed of a direct problem for the process simulation and generation of pseudo-measures, and by an inverse problem for the estimation of the interest variables by means of the particles filter. The numerical simulations allowed to understand the process and to locate the best position for the temperature sensor in the reactor. From the measurements of temperature, the proposed inferential tool estimates the latency variables and the unmeasured perturbations using the Sampling Importance Re-sampling Filter (SIR) algorithm. The filter performance is investigated according to the number of particles and the total error reduction (TER) criterion. It can be observed that the results of the numerical simulation are in agreement with the literature and that the proposed monitoring scheme was able to satisfactorily estimate the process variables and the disturbance.
- ItemEstudo da fermentação alcoólica do hidrolisado da biomassa cacaueira para produção de etanol(Universidade Federal do Espírito Santo, 2018-08-31) Kiefer, Rayane Grizotti; Pinheiro, Iara Rebouças; Guimarães, Damaris; Carreira, Lilian Gasparelli; Coelho, Jussara MoreiraAmong the residues generated by the agroindustries, it is highlighted those composed of lignocellulosic materials that can be transformed into valuable products. In order to study ways of minimizing waste and reusing them for energy production from renewable sources, it was worked with cocoa agroindustry residues to produce bioethanol through alcoholic fermentation at different initial concentrations of cells and supplementation of glucose. For this reason, an alkaline hydrogen peroxide pretreatment step (7.355% v/v) was carried out in order to facilitate the conversion of the cellulose and hemicellulose into sugars, as well as to hydrolyze with dilute sulfuric acid (0.5% w/v). During the fermentation tests under agitation at 30 ºC, with S. cerevisiae, the cell growth kinetics and the ART concentration, also the ethanol concentration was observed in 24 and 48 hours of the process. The highest ethanol levels were the ones that presented the uppermost maximum specific speed of cell growth. The highest levels of ethanol were found in the trials that presented the highest maximum specific velocity values (about 0.145 to 0.167 h-1 ), which were started with cell concentration of 0.80 and 1.00 g/L, reaching ethanol content of 5,8 and 4,3 ºGL in 48 hours, respectively. These results indicate the feasibility of the use of hydrolysate from cocoa biomass for bioethanol production.
- ItemModelagem e simulação da fermentação alcoólica em batelada e contínua com múltiplos reatores em série(Universidade Federal do Espírito Santo, 2016-02-26) Zanardi, Mayara dos Santos; Costa Junior, Esly Ferreira da; Carvalho, Raquel Vieira de; Costa, Andréa Oliveira Souza daEthanol stands out, compared to fossil fuels, because of its economic and environmental benefits. In Brazil, the second largest world producer, practically all ethanol production is obtained from the fermentation of saccharose (present in sugarcane). Improvements in the fermentation process for ethanol production could make it more competitive. In this context, this study has for objective develop a model for batch fermentation process of literature and a real industrial process that operates in a continuous mode with multiple reactors in series, using kinetic models from literature. The model for each component of interest was developed through transient mass balance on the reactor. The system of ordinary differential equations, resulting from the dynamic model, was integrated by the Runge-Kutta method of 4th order in Matlab® software. The estimation of kinetics parameters was performed by nonlinear optimization of an objective function by Nelder and Mead Simplex method. Two optimization strategies were adopted for the batch process: in the first strategy the µmax parameter is kept fixed and in the second this parameter is estimated. Six different kinetic models were tested. The estimated parameters were sensitive to small changes in experimental data set, moreover, the estimation of the parameter µmax had a strong positive influence on some models. The models Ghose and Tyagi (1979), Jin et al. (1981) and Tosetto (2002) showed the best performance in predicting the behavior of the concentration of the components in the reactor. The parameters of five kinetic models were estimated in the continuous process. The models that consider inhibition by product were better than those without this type of inhibition.
- ItemUtilização dos resíduos sólidos da indústria cacaueira para produção de etanol(Universidade Federal do Espírito Santo, 2018-02-28) Silva, Rhuany de Oliveira; Pinheiro, Iara Rebouças; Coelho, Jussara Moreira; Guimarães, DamarisThe cocoa industry generates a considerable amount of solid waste consisting mostly of fruit peel, which is mainly composed of cellulose, hemicellulose and lignin. In order for the cellulose to be accessible and can be converted into sugar, then into ethanol, a pre-treatment of the raw material is necessary, which involves an association of physical and chemical methods. This work aims to evaluate the viability of using cocoa peel as raw material for production of bioethanol. By determining the chemical composition of the peel in natura and pre-treated, by studying operational conditions of acid hydrolysis with different diluted H2SO4 and the alcoholic fermentation from the hydrolysates of the pretreated peel. In order to characterize the material, were analyzed moisture, ash, hemicellulose, cellulose, extractives and lignin. For the purpose to perform the acid hydrolysis using pre-treated cocoa peel with hydrogen peroxide (H2O2), an experimental planning of the factorial type (3²) with three central points was used, varying the acid concentration (0.20% m/v, 0.34% m/v e 0.48% m/v) and the hydrolysis time (60, 90 e 120 min.). After the hydrolysis, fermentation tests were carried out, in which the cell growth kinetics and the ethanol concentration were monitored. The experiments to characterize in natura and pre-treated peel, presented a considerable percentage of cellulose being 32.46% and 75.48%, respectively, results that indicate the efficiency of the chemical pretreatment as promisor to ethanol production. The best hydrolysis condition was obtained in 90 minutes and 0.34% w/v acid, in which approximately 13 g/L of ART was obtained. From the results of the alcoholic fermentation with supplementation of 10 g/L of glucose in the hydrolysate, it was obtained around 19% v/v (°GL).