Laboratory of Environmental and Energetic Technology

Marechal Deodoro, Brazil

Laboratory of Environmental and Energetic Technology

Marechal Deodoro, Brazil
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Cruz B.M.,Laboratory of Environmental and Energetic Technology | da Silva J.D.,Laboratory of Environmental and Energetic Technology
International Journal of Hydrogen Energy | Year: 2017

A modelling and simulation study of catalytic steam reforming of methane is presented in this paper. A two-dimensional pseudo-heterogeneous model is developed to simulate a conventional fixed-bed reactor (FBR) as well as a fixed-bed membrane reactor (FBMR) with sweep gas added in both co-current modes for the two reactor configurations. The developed model is based on mass and energy balance equations for the catalyst phase and the gas phase in both FBR and FBMR reactors. Firstly, a study is done for describing that the temperature profiles of gaseous and solid phases reach to stable state as well as the component distributions in the two FBR and FBMR reactors. The model covers the aspect of the partial pressure of hydrogen in the membrane reactor with the permeation of hydrogen across a Pd-based membrane. The conversion of methane is significantly enhanced by the partial removal of hydrogen as from the shell side as a result of diffusion through the Pdbased membrane. Simulation results demonstrated that methane conversion of 97.21% can be achieved in FBR at operating temperature of 1250 K relative to methane conversion of 99.79% to 923 K in FBMR. The yield of hydrogen achieved to level from 2.154 in FBR at operating temperature of 1250 K while the yield of hydrogen reached to level from 3.731 with a thickness from 1.7 mm in FBMR reactor. © 2017 Hydrogen Energy Publications LLC. Published by Elsevier Ltd.


Oliveira C.C.B.,Federal University of Pernambuco | Silva J.D.,Laboratory of Environmental and Energetic Technology | Araujo F.A.D.,Federal University of Pernambuco | Caldas R.,Federal University of Pernambuco | Abreu C.A.M.,Federal University of Pernambuco
Chemical Engineering Transactions | Year: 2015

Recent developments done in the scope of the biorefinery concept have emerged as alternatives to remove economic obstacles, thus making production of chemicals from ligno-cellulosic feedstocks become a reality. Biomass conversions employing pretreatments of hemicellulose and lignin, and acid hydrolysis of cellulose were carried out to break the polymeric structures. The saccharide components obtained produced reaction media that could be processed into value added polyols by subsequent hydrogenations. Copyright © 2015, AIDIC Servizi S.r.l.


Silva J.D.,Laboratory of Environmental and Energetic Technology | de Abreu C.A.M.,Federal University of Pernambuco
International Journal of Hydrogen Energy | Year: 2016

This paper presents a dynamics mathematical model to simulate the steam reforming of methane that take place in conventional fixed bed reactor (FBR) as well in fixed bed membrane reactor (FBMR) with steam added both with co-current mode. The model covers all aspects of main chemical kinetics, heat and mass phenomena in the membrane reactor with hydrogen permeation in radial direction across a Pd-based membrane. Firstly, a dynamics study was made for describing that temperatures of gaseous and solid phases reach to steady-state as well as molar flow rates. The effect several parameters including the axial position (z) divided by the reactor length Lz, reaction temperature and hydrogen partial pressure (PH2=Ppz) in permeation side were investigated. The conversion of methane is significantly enhanced by the partial removal of hydrogen from the reaction zone as a result of diffusion through the Pd-based membrane. Simulation results showed that a conversion from 99.85% could be achieved in a FBMR at reaction temperature of 600 °C relative to a conversion from 88.87% to 950 °C in a FBR. Besides, results showed that the yield of H2 reached to level from 1.548 (dynamics-state) and 1.626 (steady-state) in a FBMR at reaction temperature of 550 °C while the yield of H2 achieved to level from 1.261 (dynamics-state) and 1.445 (steady-state) in a FBR at reaction temperature of 725 °C. © 2016 Hydrogen Energy Publications LLC


Silva J.D.,Laboratory of Environmental and Energetic Technology | Abreu C.A.M.,Federal University of Pernambuco
Brazilian Journal of Chemical Engineering | Year: 2012

The transient behavior in a three-phase trickle bed reactor system (N 2/H 2O-KCl/activated carbon, 298 K, 1.01 bar) was evaluated using a dynamic tracer method. The system operated with liquid and gas phases flowing downward with constant gas flow Q G = 2.50 × 10 -6 m 3 s -1 and the liquid phase flow (Q L) varying in the range from 4.25×10 -6 m 3 s -1 to 0.50×10 -6 m 3 s -1. The evolution of the KCl concentration in the aqueous liquid phase was measured at the outlet of the reactor in response to the concentration increase at reactor inlet. A mathematical model was formulated and the solutions of the equations fitted to the measured tracer concentrations. The order of magnitude of the axial dispersion, liquid-solid mass transfer and partial wetting efficiency coefficients were estimated based on a numerical optimization procedure where the initial values of these coefficients, obtained by empirical correlations, were modified by comparing experimental and calculated tracer concentrations. The final optimized values of the coefficients were calculated by the minimization of a quadratic objective function. Three correlations were proposed to estimate the parameters values under the conditions employed. By comparing experimental and predicted tracer concentration step evolutions under different operating conditions the model was validated.


Da Silva J.D.,Laboratory of Environmental and Energetic Technology
Chemical Engineering Transactions | Year: 2015

This paper presents an one-dimensional isothermal modelling for a three-phase trickle bed system (N2/H2ONaC6H11O7/ γ-Aℓ 2O3, 298K, 1.01 bar). The transient behavior was studied using a dynamic tracer method. The system has been operated with liquid and gas phases flowing downward with constant gas flow Qg = 2.86×10-6 m3 s-1 and the liquid phase flow Qℓ varying in the range from 4.95×10-6 m3 s-1 to 1.25×10-6 m3 s-1. The evolution of the NaC6H11O7 concentration in the aqueous liquid phase was measured at the exit of the reactor in response to the concentration increase at the reactor inlet. A mathematical model was developed and the solutions of the equations fitted to the measured tracer concentrations. The order of magnitude of the axial dispersion and liquid-solid mass transfer coefficients were estimated based on a numerical optimization procedure where the initial values of these coefficients, obtained by empirical correlations, were modified by comparing experimental and calculated tracer concentrations. The final optimized values of the coefficients were calculated by the minimization of a quadratic objective function. Two correlations were proposed to estimate the parameters values under the conditions employed. By comparing experimental and predicted tracer concentration step evolutions under different operating conditions the model was validated. Copyright © 2015, AIDIC Servizi S.r.l.


Silva F.R.,Laboratory of Environmental and Energetic Technology | Silva J.D.,Laboratory of Environmental and Energetic Technology
Chemical Engineering Transactions | Year: 2015

The biomass gasification is gaining attention of scientists and researchers worldwide to be an innovative and efficient method for producing clean energy. While consuming 'junk' organic, such as sugarcane bagasse or rice husk, the gas produced in the process is used for heat or electricity generation (or gas turbine engines), synthesis of liquid fuels, hydrogen production, chemical synthesis and manufacturing of fuel cells. However, a key challenge in the development and improvement of the biomass gasification process is cleaning the gas produced in order to ensure its quality and applicability. Among the main impurities found in the gasification gas, the tar is one of the worst, the presence of this kind of impurity can prejudice the performance of the process and also damage equipment. There are several methods for tar removal. Catalytic process is the most studied and the one that shows the best results. This paper presents an isothermal mathematical model that characterizes production and consumption of tar, modelled by toluene, reforming reaction using nickelbased catalyst. A computer code in FORTRAN 90 language was developed to perform the simulation, which described the concentrations of the main components (C7H8, O2, H2 and CO), as well as the reaction yield and influence of temperature on generation of products. Then the optimum conditions for carrying out the process were determined. Copyright © 2015, AIDIC Servizi S.r.l.


Silva J.D.,Laboratory of Environmental and Energetic Technology
Chemical Engineering Transactions | Year: 2014

This paper presents an one-dimensional isothermal modelling for a CFBMR (H2 permeable). The work has been developed to simulate the SRM to produce H2. The dynamic simulation for molar flow rates of H2 was analyzed in the permeation side and shell side zones at different temperatures at the exit of the proposed system. The model has allowed the validation for the conversion of CH4 by comparing of optimized values. Additionally, the molar flow rates for chemical species (CH4, H2O, H2, CO and CO2) were analyzed along of the CFBMR (shell side) at t = 14 s, a comparison between permeation side and shell side for H2 and the molar flow rates of H2 in the permeation side and shell side zones at different temperatures.. Copyright © 2014, AIDIC Servizi S.r.l.

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