Repositorio Institucional Universidad EAFIT ::Examinando por Autor "GilPavas, E."

Examinando por Autor "GilPavas, E."

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Análisis de la sensibilidad paramétrica y del comportamiento dinámico de la hidrólisis del isocianato de metilo
(Centro de Informacion Tecnologica, 2016-01-01) Ojeda, J.C.; GilPavas, E.; Dobrosz-Gómez, I.; Gómez, M.A.; Ojeda, J.C.; GilPavas, E.; Dobrosz-Gómez, I.; Gómez, M.A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
In this work, parametric sensitivity and dynamic analysis were combined to determine the thermal instability conditions inherent in the methyl isocyanate hydrolysis reaction. This highly exothermic reaction tragically proved to be very sensible to temperature changes in the so-called Bhopal disaster in 1984. A stirred tank reactor in transient state was considered for simulating the reactive system. First, critical operational conditions were defined from the parametric sensitivity analysis. Subsequently, in a rigorous way, the dynamic analysis determined the thermal instability regions, Hopf bifurcations, and the thermal oscillatory behavior of the reactive system. The Matcont® software was used to solve the differential equations set. It was demonstrated that runaway conditions and the periodic solutions of temperature are closely related with the cooling temperature and the dimensionless parameters (f-dimensionless flow and l-heat transfer term) and their critical parameters were obtained: /c=752.39 and fc=1.57.
Coagulation-flocculation sequential with Fenton or Photo-Fenton processes as an alternative for the industrial textile wastewater treatment
(Editorial Board, 2017-04-15) GilPavas, E.; Dobrosz-Gómez, I.; Gómez-García, M.Á.; GilPavas, E.; Dobrosz-Gómez, I.; Gómez-García, M.Á.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
In this study, the industrial textile wastewater was treated using a chemical-based technique (coagulation-flocculation, C-F) sequential with an advanced oxidation process (AOP: Fenton or Photo-Fenton). During the C-F, Al2(SO4)3 was used as coagulant and its optimal dose was determined using the jar test. The following operational conditions of C-F, maximizing the organic matter removal, were determined: 700 mg/L of Al2(SO4)3 at pH = 9.96. Thus, the C-F allowed to remove 98% of turbidity, 48% of Chemical Oxygen Demand (COD), and let to increase in the BOD5/COD ratio from 0.137 to 0.212. Subsequently, the C-F effluent was treated using each of AOPs. Their performances were optimized by the Response Surface Methodology (RSM) coupled with a Box-Behnken experimental design (BBD). The following optimal conditions of both Fenton (Fe2+/H2O2) and Photo-Fenton (Fe2+/H2O2/UV) processes were found: Fe2+ concentration = 1 mM, H2O2 dose = 2 mL/L (19.6 mM), and pH = 3. The combination of C-F pre-treatment with the Fenton reagent, at optimized conditions, let to remove 74% of COD during 90 min of the process. The C-F sequential with Photo-Fenton process let to reach 87% of COD removal, in the same time. Moreover, the BOD5/COD ratio increased from 0.212 to 0.68 and from 0.212 to 0.74 using Fenton and Photo-Fenton processes, respectively. Thus, the enhancement of biodegradability with the physico-chemical treatment was proved. The depletion of H2O2 was monitored during kinetic study. Strategies for improving the reaction efficiency, based on the H2O2 evolution, were also tested. © 2017 Elsevier Ltd
Coagulation-flocculation sequential with Fenton or Photo-Fenton processes as an alternative for the industrial textile wastewater treatment
(Editorial Board, 2017-04-15) GilPavas, E.; Dobrosz-Gómez, I.; Gómez-García, M.Á.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
In this study, the industrial textile wastewater was treated using a chemical-based technique (coagulation-flocculation, C-F) sequential with an advanced oxidation process (AOP: Fenton or Photo-Fenton). During the C-F, Al2(SO4)3 was used as coagulant and its optimal dose was determined using the jar test. The following operational conditions of C-F, maximizing the organic matter removal, were determined: 700 mg/L of Al2(SO4)3 at pH = 9.96. Thus, the C-F allowed to remove 98% of turbidity, 48% of Chemical Oxygen Demand (COD), and let to increase in the BOD5/COD ratio from 0.137 to 0.212. Subsequently, the C-F effluent was treated using each of AOPs. Their performances were optimized by the Response Surface Methodology (RSM) coupled with a Box-Behnken experimental design (BBD). The following optimal conditions of both Fenton (Fe2+/H2O2) and Photo-Fenton (Fe2+/H2O2/UV) processes were found: Fe2+ concentration = 1 mM, H2O2 dose = 2 mL/L (19.6 mM), and pH = 3. The combination of C-F pre-treatment with the Fenton reagent, at optimized conditions, let to remove 74% of COD during 90 min of the process. The C-F sequential with Photo-Fenton process let to reach 87% of COD removal, in the same time. Moreover, the BOD5/COD ratio increased from 0.212 to 0.68 and from 0.212 to 0.74 using Fenton and Photo-Fenton processes, respectively. Thus, the enhancement of biodegradability with the physico-chemical treatment was proved. The depletion of H2O2 was monitored during kinetic study. Strategies for improving the reaction efficiency, based on the H2O2 evolution, were also tested. © 2017 Elsevier Ltd
Foto-degradación de fenol sobre catalizadores de TiO2 y Mo/TiO2. La metodología de superficie de respuesta como herramienta de optimización
(Centro de Informacion Tecnologica, 2014-01-01) López-Zamora, S.M.; GilPavas, E.; Gómez-García, M.Á.; Dobrosz-Gómez, I.; López-Zamora, S.M.; GilPavas, E.; Gómez-García, M.Á.; Dobrosz-Gómez, I.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
In this work, the response surface methodology was applied as a tool for the optimization of the operational conditions of phenol photo-degradation over TiO2 and 2% wt Mo/TiO2 catalysts. A multifactorial experimental design was proposed, including the following variables: phenol initial concentration (Ci), catalyst loading (Cat) and pH. The apparent reaction rate constant and the percentage of phenol degradation were chosen as the response variables. When TiO2 was used as catalyst, the following optimal operational conditions were found: Ci=10ppm, Cat=0.7g/L and pH=8 for both UV and visible light. For 2% wt Mo/TiO2 catalyst, the optimal operating conditions strongly depended on the applied radiation source. Thus, under UV radiation: Ci=10 ppm, Cat=0.7 g/L and pH=8 were found as the optimum conditions. Using visible light, and the following optimized conditions, Ci=10 ppm, Cat=0.1 g/L, pH =3.6, the Mo containing catalyst showed to be the most efficient. Under these conditions, the amount of 2% wt. Mo/TiO2 was 7 times lower than that of unsupported TiO2.
Kinetic study on HCN volatilization in gold leaching tailing ponds
(Elsevier Ltd, 2017-08-15) Dobrosz-Gómez, I.; Ramos García, B.D.; GilPavas, E.; Gómez García, M.Á.; Dobrosz-Gómez, I.; Ramos García, B.D.; GilPavas, E.; Gómez García, M.Á.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
In this work, the detailed analysis of HCN volatilization, taking place in tailing storage facilities, was made. Volatilization experiments were performed at conditions typical of gold leaching industrial tailing ponds. The meticulous statistical analysis (including full factorial 33 experimental design) let to determine the variables and their interactions affecting the percentage of HCN volatilization. Volatilization tests were performed in an open, temperature-controlled, continuously-stirred batch reactor. The percentage of HCN volatilization was directly proportional to the temperature and temperature-pH interaction and inversely proportional to the pH, cyanide concentration, and pH-pH and temperature-cyanide concentration interactions. HCN volatilization was promoted at acidic conditions. A first order rate law was used to represent the volatilization rate. The specific rate constant (k) was found to be following function of temperature and pH: k(T,pH) = Ao.exp(-18760/T), where: In(A(0)) = (0.11 +/- 0.11)-pH + (58.08 +/- 0.16). The obtained kinetic model represented properly (R-2 = 0.90) experimental data in a wide range of industrial conditions: cyanide concentration (300-2000 mg.L-1), pH (3-9), and temperature (16-20 degrees C). The increase in temperature, from 16 to 20 C, let to the increase in k, by a factor of ca. 2.5 +/- 0.8. The increase in solution pH, from 3 to 9, provoked its decrease, by a factor of ca. 1.9 +/- 0.3.
Kinetic study on HCN volatilization in gold leaching tailing ponds
(Elsevier Ltd, 2017-08-15) Dobrosz-Gómez, I.; Ramos García, B.D.; GilPavas, E.; Gómez García, M.Á.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Desarrollo y Diseño de Procesos
In this work, the detailed analysis of HCN volatilization, taking place in tailing storage facilities, was made. Volatilization experiments were performed at conditions typical of gold leaching industrial tailing ponds. The meticulous statistical analysis (including full factorial 33 experimental design) let to determine the variables and their interactions affecting the percentage of HCN volatilization. Volatilization tests were performed in an open, temperature-controlled, continuously-stirred batch reactor. The percentage of HCN volatilization was directly proportional to the temperature and temperature-pH interaction and inversely proportional to the pH, cyanide concentration, and pH-pH and temperature-cyanide concentration interactions. HCN volatilization was promoted at acidic conditions. A first order rate law was used to represent the volatilization rate. The specific rate constant (k) was found to be following function of temperature and pH: k(T,pH) = Ao.exp(-18760/T), where: In(A(0)) = (0.11 +/- 0.11)-pH + (58.08 +/- 0.16). The obtained kinetic model represented properly (R-2 = 0.90) experimental data in a wide range of industrial conditions: cyanide concentration (300-2000 mg.L-1), pH (3-9), and temperature (16-20 degrees C). The increase in temperature, from 16 to 20 C, let to the increase in k, by a factor of ca. 2.5 +/- 0.8. The increase in solution pH, from 3 to 9, provoked its decrease, by a factor of ca. 1.9 +/- 0.3.
Optimización de los Costos de Operación del Proceso de Electro-oxidación para una Planta de Tratamiento de Aguas Mediante Análisis Estadístico de Superficie de Respuesta
(Centro de Informacion Tecnologica, 2016-01-01) GilPavas, E.; Medina, J.; Dobrosz-Gómez, I.; Gómez, M.-A.; GilPavas, E.; Medina, J.; Dobrosz-Gómez, I.; Gómez, M.-A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
The statistical optimization of the implementation and operational costs of an electrochemical-oxidation process for treatment of wastewater containing dye Yellow 23 was done. The aim was to optimize the operational parameters for the current density, conductivity, and area of electrodes per unit of volume in order to minimize the net present value (NPV) of the operation while maintaining a defined quality for the treated wastewater. To achieve this, the response surface methodology coupled to the Box-Behnken statistical design was used. The optimal conditions found were: a relationship of treated wastewater volume per area of electrodes of 9.076 mL/cm2, conductivity 4000 µS/cm, and current density 20 mA/cm2. At optimal conditions, the NPV for a 10 year operation is 998636 USD, which corresponds to a cost of 0.68USD/m3 of treated water.
The removal of the trivalent chromium from the leather tannery wastewater: the optimisation of the electro-coagulation process parameters.
(IWA PUBLISHING, 2011-02-01) GilPavas, E.; Dobrosz-Gomez, I.; Gomez-Garcia, M. A.; GilPavas, E.; Dobrosz-Gomez, I.; Gomez-Garcia, M. A.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
The capacity of the electro-coagulation (EC) process for the treatment of the wastewater containing Cr3+, resulting from a leather tannery industry placed in Medellin (Colombia), was evaluated. In order to assess the effect of some parameters, such as: the electrode type (Al and/or Fe), the distance between electrodes, the current density, the stirring velocity, and the initial Cr3+ concentration on its efficiency of removal (%RCr+3), a multifactorial experimental design was used. The %RCr3+ was defined as the response variable for the statistical analysis. In order to optimise the operational values for the chosen parameters, the response surface method (RSM) was applied. Additionally, the Biological Oxygen Demand (BOD5), the Chemical Oxygen Demand (COD), and the Total Organic Carbon (TOC) were monitored during the EC process. The electrodes made of aluminium appeared to be the most effective in the chromium removal from the wastewater under study. At pH equal to 4.52 and at 28 degrees C, the optimal conditions of Cr3+ removal using the EC process were found, as follows: the initial Cr3+ concentration=3,596 mg/L, the electrode gap=0.5 cm, the stirring velocity=382.3 rpm, and the current density=57.87 mA/cm2. At those conditions, it was possible to reach 99.76% of Cr3+ removal, and 64% and 61% of mineralisation (TOC) and COD removal, respectively. A kinetic analysis was performed in order to verify the response capacity of the EC process at optimised parameter values.
Sensibilidad Paramétrica y Condiciones Seguras de Operación de la Hidrólisis del Anhídrido Acético en un Reactor Batch
(Centro de Informacion Tecnologica, 2016-01-01) Gaviria, G.H.; GilPavas, E.; Dobrosz-Gómez, I.; Gómez, M.Á.; Gaviria, G.H.; GilPavas, E.; Dobrosz-Gómez, I.; Gómez, M.Á.; Universidad EAFIT. Departamento de Ingeniería de Procesos; Procesos Ambientales (GIPAB)
The results of a study on the parametric sensitivity of acetic acid production by hydrolysis of acetic anhydride, using acid homogeneous catalysis in a batch reactor, are presented. Dimensionless parameters of mass and energy balances were fitted using experimental data available in the literature that includes the variation of the reaction temperature for different sulfuric acid concentrations (3% to 5%). Then, from the analysis of the intrinsic mathematical properties of the concentration-temperature phase plane, the critical operating conditions were defined. Thus, it was possible to determine the specific values of the safe operating conditions for the catalyzed hydrolysis of acetic anhydride, in the function of catalyst concentration.

Examinando por Autor "GilPavas, E."

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