Environmental and Energetic Technology Laboratory

Marechal Deodoro, Brazil

Environmental and Energetic Technology Laboratory

Marechal Deodoro, Brazil

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Silva J.D.,Environmental and Energetic Technology Laboratory
Procedia Engineering | Year: 2012

Experimental evaluation and dynamic modelling were presented for the transient behavior of a trickle bed reactor in which gas and liquid streams flow downwards through a bed of catalyst particles. One-dimensional dynamic mathematical model has been described to study the gas-liquid-solid process in which the gas phase (Ar) with the tracer (SO2) is treated as a continuum. The physical model has been analyzed, including the formulation of initial and boundary conditions and the description of the solution methodology. An experimental procedure to measure the concentrations of the tracer (SO 2) has been performed. The concentration measurements for this tracer (SO2) were performed in a fixed be reactor on trickling flow of the gas phase for a range of operating conditions. The gas-liquid mass transfer (kgl) coefficient, liquid-solid mass transfer (kls) coefficient, gas holdup (hg) and partial wetting efficiency (f e) were chosen as the hydrodynamic parameters of the proposed mathematical model. Such parameters have been optimized with the experimental measurents of the tracer (SO2) at the exit of the trickle-bed reactor. The optimized parameters hg, kgl, kls and f e were calculated simultaneously using the equation (51) with minimization of the objective function. Results of the mathematical model was presented and compared to the two experimental cases. Each above parameters were correlated using empirical correlations. © 2012 Published by Elsevier Ltd.


Silva J.D.,Environmental and Energetic Technology Laboratory | Oliveira C.C.B.,Environmental and Energetic Technology Laboratory
Procedia Engineering | Year: 2012

The fluidynamics presented in this paper for a fixed bed gasifier consists of estimating the volume fraction fields of gas and solid phases, as well as the velocity fields of gas and solid phases and the pressure inside the fixed bed. However, understanding of the flow characteristics has an important role in understanding of the operation of the gasifier. The analyzed system consists of the fundamental equations of mass balance for the gas and solid phases, as well as the equations of momentum balance for gas and solid phases and an equation for the pressure given by the sum of the momentum balance equations of the gas and solid phases. The sets of equations developed form a system of one-dimensional partial differential equations (PDEs). The PDEs system has been transformed in a coupled ordinary differential equation (ODEs) system using Laplace Transform. The ODEs system has been solved using an implementation of the finite difference method (FDM). The objective of this work is to obtain the profiles of state variables such as volume fraction of gas (εg) and solid phases (εs), the velocity profiles of gas (v g) and solid phase (vs) and pressure field (p f). © 2012 Published by Elsevier Ltd.


Teles V.H.B.,Environmental and Energetic Technology Laboratory | Da Silva J.D.,Environmental and Energetic Technology Laboratory
Chemical Engineering Transactions | Year: 2015

Proposed model for H2S was analyzed using a stationary adsorbent bed allowing continuous operation. The numerical method of inverse Laplace transform was used to solve the one-dimensional isothermal mathematical model that describes the process. For the simulation, a computer code in Fortran 90 language was developed to solve the problem in dynamic regime. The objective of this research has been to formulate a robust mathematical model for the adsorption process of H2S on nanostructured solid (NaX) at 25 °C and pressures at 1.01 bar. The adsorption capacity of catalytic adsorbent using H2S has been analyzed as well as the simulation of H2S in liquid and solid phases for different initial superficial velocities.


Oliveira C.C.,Environmental and Energetic Technology Laboratory | Da Silva J.D.,Environmental and Energetic Technology Laboratory
Chemical Engineering Transactions | Year: 2012

This paper focuses on the dynamic mathematical model using algorithm of Runge-Kutta method Gill's method in predicting the process variables (temperatures and mole fractions of components "i" in the feed) in the gasification region for a bubbling fluidized bed coal gasifier. The discretized dynamic mathematical model has formed an ordinary differential equation (ODEs) system. The system of EDOs will was solved with the implementation of Runge-Kutta method Gill's method to examine the temperature behaviors of gaseous and solid phases as well as the mole fraction profiles for O2, CO, CO2, H2O, H2 and C(s). A model validation procedure was conducted to obtain by comparing the model confirmations using available data of the literature. Copyright © 2012, AIDIC Servizi S.r.l.


Oliveira C.C.B.,Environmental and Energetic Technology Laboratory | Da Silva J.D.,Environmental and Energetic Technology Laboratory
Chemical Engineering Transactions | Year: 2013

The study presents a mathematical model to analyze the dynamic evolution of molar concentrations for toluene (C7H8), water vapor (H2O) carbon monoxide (CO), hydrogen (H2), methane (CH4) and carbon dioxide (CO2) in fixed bed catalytic reactor. The mathematical model was discretized using the method of lines (MDLs) to transform the system of partial differential equations (PDEs) in a system of ordinary differential equations (ODE). The system of ODEs has been solved by the implementation of the Runge-Kutta Gill to estimate the chemical species C7H8, H2, CO, H2, CH4 and CO2. The estimation allows the quantification of individual forecasts of the variables presented in this study. However, valuable information can be obtained from the estimated behaviors in fixed bed catalytic reactor. The model has allowed the validation of chemical species (H 2, CO and CO2) by comparing the optimized values. Additionally, the concentrations for the chemical species C7H 8, H2, CO, H2, CH4 and CO 2 was studied. © 2013, AIDIC Servizi S.r.l.


Da Silva J.D.,Environmental and Energetic Technology Laboratory | Oliveira C.C.,Environmental and Energetic Technology Laboratory
Chemical Engineering Transactions | Year: 2013

Theoretical analysis on the CO2 adsorption on NaX has been carried out in fixed bed reactor. In the proposed process, CO2 was passed through a stationary adsorbent bed allowing continuous operation. A one-dimensional and isothermal model was proposed to describe the adsorption process of CO2. Attention has been focused on a mathematical model to simulate the transient behavior of dissolved CO2 within the gas phase and then adsorbed into the nanopores of the solid phase (adsorbent). The simulation results were compared to the one experimental case. After, it was performed a sensibility analysis in relation to CO2 concentration within of the nanopores of the solid phase as well as accounting for the amount of adsorbed CO2 in the nanopores of the solid phase. Copyright © 2013, AIDIC Servizi S.r.l.

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