Dr.Mallaiah Mekala - Academia.edu (original) (raw)

Papers by Dr.Mallaiah Mekala

Research paper thumbnail of Water Removal from an Ethanol-Water Mixture at Azeotropic Condition by Adsorption Technique

Adsorption Science & Technology

The separation of ethanol-water mixture is employed in the present work to produce pure ethanol, ... more The separation of ethanol-water mixture is employed in the present work to produce pure ethanol, the present investigation on the separation of water from the ethanol to achieve pure ethanol by adsorption process. The different parameters like quantity of adsorbent, flow rate of feed mixture, and different adsorbents which are zeolite 3A, zeolite 4A, and silica gel are selected to study purification of ethanol by adsorption. The effect of process parameter for purification is also recorded and studied to evaluate the performance of adsorption equipment and adsorbent. The experiments are conducted at 30°C. The feed mixture is 95.6% (v/v) concentration of ethanol and 4.4% (v/v) of water. The designed adsorption column is suitable for purification of ethanol. The highest ethanol concentration 99.9443% obtained at 20 ml/min flow rate of feed mixture using 50 g of zeolite.

Research paper thumbnail of Experimental and simulation studies of a continuous reactive distillation for an esterification process

International Journal of Chemical Reactor Engineering, 2022

Esterification of acetic acid and methanol to produce methyl acetate and water has been studied i... more Esterification of acetic acid and methanol to produce methyl acetate and water has been studied in a continuous packed bed catalytic reactive distillation column. Indion 180, an ion-exchange resin solid catalyst has loaded in an equivalent Katapak-S into the reactive section of the column. The experiments were conducted under different operating conditions of reboiler temperature, total feed flow rate of the reactants, methanol to acetic acid mole ratio, feed location of acetic acid and methanol with respect to reactive section, reflux ratio and catalyst amount to investigate the composition of distillate and reboiler respectively. The maximum methyl acetate composition and acetic acid conversion is obtained at reboiler temperature of 80 °C, reflux ratio of 2, total feed flow rate of 16.3 g/min, catalyst loading of 60 g and mole ratio of methanol to acetic acid is 1. From the experimental investigations, it is found that the composition of the methyl acetate in the distillate is 95%...

Research paper thumbnail of Simulation of steady state continuous catalytic reactive distillation column using a novel multiscale capillary model

Chemical Engineering & Technology, 2022

Research paper thumbnail of Dynamic Simulation of Heterogeneous Catalysis at Particle Scale to Estimate the Kinetic Parameters for the Pore Diffusion Model

Bulletin of Chemical Reaction Engineering & Catalysis, 2018

In this work, dynamic simulation at particle scale is carried out to predict the kinetics of soli... more In this work, dynamic simulation at particle scale is carried out to predict the kinetics of solid catalyzed esterification reaction between acetic acid and methanol to produce methyl acetate and water. The reaction kinetic data utilized for modeling and validation is with solid catalyst as Indion 180. It was observed that the reaction rate and kinetics inside the pores of the catalyst is of higher magnitude as compared to bulk liquid. Each solid catalyst particle is surrounded by reactant solution of equal volume. A dynamic simulation is carried out using COMSOL Multiphysics which has solver for diffusion-reaction equation for both in liquid phase and inside porous catalyst particle. The intrinsic reaction rate constants for bulk liquid phase and inside the particle are obtained by solving the full diffusion-reaction equation and optimization method. Three different models (model 1,2,3) were proposed for evaluating the rate constants from the experimental kinetic data. The three mo...

Research paper thumbnail of Experimental design data for the biosynthesis of citric acid using Central Composite Design method

Data in Brief, 2017

In the present investigation, we report that statistical design and optimization of significant v... more In the present investigation, we report that statistical design and optimization of significant variables for the microbial production of citric acid from sucrose in presence of filamentous fungi A. niger NCIM 705. Various combinations of experiments were designed with Central Composite Design (CCD) of Response Surface Methodology (RSM) for the production of citric acid as a function of six variables. The variables are; initial sucrose concentration, initial pH of medium, fermentation temperature, incubation time, stirrer rotational speed, and oxygen flow rate. From experimental data, a statistical model for this process has been developed. The optimum conditions reported in the present article are initial concentration of sucrose of 163.6 g/L, initial pH of medium 5.26, stirrer rotational speed of 247.78 rpm, incubation time of 8.18 days, fermentation temperature of 30.06°C and flow rate of oxygen of 1.35 lpm. Under optimum conditions the predicted maximum citric acid is 86.42 g/L. The experimental validation carried out under the optimal values and reported citric acid to be 82.0 g/L. The model is able to represent the experimental data and the agreement between the model and experimental data is good.

Research paper thumbnail of Comparative kinetics of esterification of methanol-acetic acid in the presence of liquid and solid catalysts

Asia-Pacific Journal of Chemical Engineering, 2014

Esterification of acetic acid with methanol to produce methyl acetate in an isothermal stirred ba... more Esterification of acetic acid with methanol to produce methyl acetate in an isothermal stirred batch reactor has been studied. Sulfuric acid was used as a liquid catalyst, and Indion-180, Indion-190 and Amberlyst-16wet ion exchange resins were used as solid catalysts. The feed mole ratio was varied from 1 : 1 to 1 : 4. The reaction temperatures were varied from 305.15 to 333.15 K for sulfuric acid as catalyst and 323.15 to 353.15 K for the solid catalysts. The catalyst concentrations were used in the range of 1% to 5%, for the sulfuric acid catalyst, and 0.01 to 0.05 g/cc, for the solid catalysts. The effect of temperature, catalyst concentration, agitation speed, size of catalyst particle and reactant concentration on the acetic acid conversion was investigated. A second-order kinetic rate equation was proposed to fit the experimental data. For both forward and backward reactions, the activation energies were estimated from Arrhenius plots. The reaction rate increased with catalyst concentration and temperature for both the liquid and solid catalysts. The acetic acid conversion was found to increase with increases in acetic acid to methanol ratio in the feed. The developed kinetic rate equation was used for the simulation of reactive distillation process, in our laboratory column.

Research paper thumbnail of Kinetics of esterification of methanol and acetic acid with mineral homogeneous acid catalyst

Chinese Journal of Chemical Engineering, 2015

Comparison of different kinetic models at 313 K and 0.3268 mol•L-1 catalyst concentration. Experi... more Comparison of different kinetic models at 313 K and 0.3268 mol•L-1 catalyst concentration. Experimental; Concentration based; activity based; Liu et al. [8]; Elugu et al. [9]; Bonnaillie et al. [15]; Agreda et al. [5] Catalysis, Kinetics and Reaction Engineering Kinetics of Esterification of Methanol and Acetic Acid with Mineral Homogeneous Acid

Research paper thumbnail of Developmental outcome of children with early transient thyroid hormone imbalances

Research paper thumbnail of Data on acetic acid–methanol–methyl acetate–water mixture analysised by dual packed column Gas Chromatography

Data in Brief

The composition of multicomponent determination by colorimetric titration is difficult. This comp... more The composition of multicomponent determination by colorimetric titration is difficult. This complexity is easily overcome by using Gas Chromatography technique instead of wet method for multi-component mixture analysis. In Gas Chromatography, first the standard chart is prepared by using the known amount sample concentration as the reference. Once calibration chart is prepared the unknown sample concentration easily measured by using the standard chart. In the present study a standard calibration chart developed for the four component system of acetic acid-methanol-methyl acetate-water. The samples were taken at various concentrations of all components and different chromatograms obtained under various concentrations respectively. The method of optimization was first carried out to get the sharp peaks of individual components and binary pairs also. By using those conditions, the multi components concentrations were estimated. From the present results, the area under gas chromatogram is linearly varying with mole% of the components compared to mass%.

Research paper thumbnail of Preparation of Ti Material Supported SBA-15 Functionalized with Sulfonic Acid Environmental Friendly Catalyst: Application for Esterification Process

Journal of Nanomaterials

Kinetics of catalytic esterification between propionic acid and n-butanol has been studied in a b... more Kinetics of catalytic esterification between propionic acid and n-butanol has been studied in a batch reactor by using a Ti-supported SBA-15 catalyst with sulfonic acid. The synthesized catalyst is used to test the efficacy of catalyst for esterification reaction. The SBA-15 acidity is tied to incorporation of Ti and -SO3H groups through and the use of Si/Ti with Si/S molar ratios. The results are mesoporous materials with a typical hexagonal structure of the Ti SBA-15 and wide areas and high pore diameters that are operated with sulfonic groups. The addition of SBA to Ti leads mainly to catalytic materials with Bronsted and Lewis acid sites. Ti SBA-15 is the most effective catalyst for sulfonic acid, with the highest consents of Lewis acid sites and deactivation resistance and low hydrophilicity. The effect of temperature, catalyst amount, and molar ratio on reaction kinetics has been studied. The conversion of propionic acid is found to be 91% at 115°C at a 2 : 1 ratio of n-butano...

Research paper thumbnail of Kinetic Modelling and Simulation Studies for the Esterification Process with Amberlyst 16 Resin

The reaction of methanol with acetic acid in a simple isothermal batch reactor was carried out to... more The reaction of methanol with acetic acid in a simple isothermal batch reactor was carried out to produce methyl acetate and water with and without catalyst. Amberlyst 16 used as the solid resin catalyst. The reaction mixture temperature was adjusted for 313.15 K - 353.15 K with and without Amberlyst 16. The concentration for catalyst changed from 0.048 mol H + /L - 0.24 mol H + /L based on volume of mixture. The reactant mole ratio for acid to alcohol was varied from 1:1 - 1:4. The influence of catalyst loading, reaction mixture temperature, initial reactant mole ratio, catalyst size, agitation speed on acetic acid conversion has been investigated. An experimental results show that reaction is kinetically controlled when compared to internal and external mass transfer effects. Kinetic rate equation of second order is used to fit experimental data. The reaction rate constants and activation energies were calculated from Arrhenius plot with and without catalyst. This equation ca...

Research paper thumbnail of Kinetic studies on esterification of acetic acid with isopropyl alcohol in presence of novel solid catalyst

The reaction of isopropyl alcohol with acetic acid was carried out in an isothermal batch reactor... more The reaction of isopropyl alcohol with acetic acid was carried out in an isothermal batch reactor in presence of solid resin catalyst to produce isopropyl acetate and water. A novel solid resin catalyst Indion 140 was used in the present study. The temperature of reaction mixture was maintained in the range of 333.15 – 363.15 K. The effects of reaction temperature, catalyst loading, mole ratio, size of catalyst, agitation speed were investigated on acetic acid conversion. Further, pseudo-homogeneous kinetic model was developed for the catalyzed reaction. The forward reaction rate constants and activation energies were determined from the Arrhenius plot. The forward and backward activation energies are found to 53,459 J/mol and 54,748 J/mol, respectively. The heat of reaction is −1.289 kJ/mol with Indion 140 catalyst. The mathematical equation was developed for frequency factor as function of the catalyst loading and found that it follows a linear relationship between frequency facto...

Research paper thumbnail of Pore diffusion model to predict the kinetics of heterogeneous catalytic esterification of acetic acid and methanol

Research paper thumbnail of Kinetics of esterification of acetic acid and methanol using Amberlyst 36 cation-exchange resin solid catalyst

Progress in Reaction Kinetics and Mechanism, 2015

Research paper thumbnail of Data on Conceptual design and Simulation of Reactive Distillation process

Data in Brief, Dec 1, 2019

Research paper thumbnail of Data on acetic acid–methanol–methyl acetate–water mixture analysised by dual packed column Gas Chromatography

Research paper thumbnail of Optimization Studies on Biosynthesis of Citric Acid by One-Factor-at-a-Time

Chemistry & Chemical Technology

In the presented study, the significant operating variables regarding biosynthesis of citric acid... more In the presented study, the significant operating variables regarding biosynthesis of citric acid process were assessed and their effects on the process yield were analysed. These variables, namely, initial sucrose concentration, methanol concentration, inoculum density, initial medium pH, spore age, stirrer speed, incubation period, fermentation temperature, particle size distribution, oxygen flow rate, and moisture content have significant influence on bioprocess of citric acid production. Plackett-Burman approach was used to determine the most significant variables, which predominantly influence the citric acid production process. Out of the eleven variables, initial sucrose concentration, initial medium pH, stirrer speed, incubation period, fermentation temperature, and oxygen flow rate were found to be significant. The effect of the significant variables on the yield of citric acid has been validated experimentally by one-factor-at-a-time empirical optimization technique. The optimum conditions have been determined. The effect of each variable on the yield of citric acid was analysed critically.

Research paper thumbnail of Water Removal from an Ethanol-Water Mixture at Azeotropic Condition by Adsorption Technique

Adsorption Science & Technology

The separation of ethanol-water mixture is employed in the present work to produce pure ethanol, ... more The separation of ethanol-water mixture is employed in the present work to produce pure ethanol, the present investigation on the separation of water from the ethanol to achieve pure ethanol by adsorption process. The different parameters like quantity of adsorbent, flow rate of feed mixture, and different adsorbents which are zeolite 3A, zeolite 4A, and silica gel are selected to study purification of ethanol by adsorption. The effect of process parameter for purification is also recorded and studied to evaluate the performance of adsorption equipment and adsorbent. The experiments are conducted at 30°C. The feed mixture is 95.6% (v/v) concentration of ethanol and 4.4% (v/v) of water. The designed adsorption column is suitable for purification of ethanol. The highest ethanol concentration 99.9443% obtained at 20 ml/min flow rate of feed mixture using 50 g of zeolite.

Research paper thumbnail of Experimental and simulation studies of a continuous reactive distillation for an esterification process

International Journal of Chemical Reactor Engineering, 2022

Esterification of acetic acid and methanol to produce methyl acetate and water has been studied i... more Esterification of acetic acid and methanol to produce methyl acetate and water has been studied in a continuous packed bed catalytic reactive distillation column. Indion 180, an ion-exchange resin solid catalyst has loaded in an equivalent Katapak-S into the reactive section of the column. The experiments were conducted under different operating conditions of reboiler temperature, total feed flow rate of the reactants, methanol to acetic acid mole ratio, feed location of acetic acid and methanol with respect to reactive section, reflux ratio and catalyst amount to investigate the composition of distillate and reboiler respectively. The maximum methyl acetate composition and acetic acid conversion is obtained at reboiler temperature of 80 °C, reflux ratio of 2, total feed flow rate of 16.3 g/min, catalyst loading of 60 g and mole ratio of methanol to acetic acid is 1. From the experimental investigations, it is found that the composition of the methyl acetate in the distillate is 95%...

Research paper thumbnail of Simulation of steady state continuous catalytic reactive distillation column using a novel multiscale capillary model

Chemical Engineering & Technology, 2022

Research paper thumbnail of Dynamic Simulation of Heterogeneous Catalysis at Particle Scale to Estimate the Kinetic Parameters for the Pore Diffusion Model

Bulletin of Chemical Reaction Engineering & Catalysis, 2018

In this work, dynamic simulation at particle scale is carried out to predict the kinetics of soli... more In this work, dynamic simulation at particle scale is carried out to predict the kinetics of solid catalyzed esterification reaction between acetic acid and methanol to produce methyl acetate and water. The reaction kinetic data utilized for modeling and validation is with solid catalyst as Indion 180. It was observed that the reaction rate and kinetics inside the pores of the catalyst is of higher magnitude as compared to bulk liquid. Each solid catalyst particle is surrounded by reactant solution of equal volume. A dynamic simulation is carried out using COMSOL Multiphysics which has solver for diffusion-reaction equation for both in liquid phase and inside porous catalyst particle. The intrinsic reaction rate constants for bulk liquid phase and inside the particle are obtained by solving the full diffusion-reaction equation and optimization method. Three different models (model 1,2,3) were proposed for evaluating the rate constants from the experimental kinetic data. The three mo...

Research paper thumbnail of Experimental design data for the biosynthesis of citric acid using Central Composite Design method

Data in Brief, 2017

In the present investigation, we report that statistical design and optimization of significant v... more In the present investigation, we report that statistical design and optimization of significant variables for the microbial production of citric acid from sucrose in presence of filamentous fungi A. niger NCIM 705. Various combinations of experiments were designed with Central Composite Design (CCD) of Response Surface Methodology (RSM) for the production of citric acid as a function of six variables. The variables are; initial sucrose concentration, initial pH of medium, fermentation temperature, incubation time, stirrer rotational speed, and oxygen flow rate. From experimental data, a statistical model for this process has been developed. The optimum conditions reported in the present article are initial concentration of sucrose of 163.6 g/L, initial pH of medium 5.26, stirrer rotational speed of 247.78 rpm, incubation time of 8.18 days, fermentation temperature of 30.06°C and flow rate of oxygen of 1.35 lpm. Under optimum conditions the predicted maximum citric acid is 86.42 g/L. The experimental validation carried out under the optimal values and reported citric acid to be 82.0 g/L. The model is able to represent the experimental data and the agreement between the model and experimental data is good.

Research paper thumbnail of Comparative kinetics of esterification of methanol-acetic acid in the presence of liquid and solid catalysts

Asia-Pacific Journal of Chemical Engineering, 2014

Esterification of acetic acid with methanol to produce methyl acetate in an isothermal stirred ba... more Esterification of acetic acid with methanol to produce methyl acetate in an isothermal stirred batch reactor has been studied. Sulfuric acid was used as a liquid catalyst, and Indion-180, Indion-190 and Amberlyst-16wet ion exchange resins were used as solid catalysts. The feed mole ratio was varied from 1 : 1 to 1 : 4. The reaction temperatures were varied from 305.15 to 333.15 K for sulfuric acid as catalyst and 323.15 to 353.15 K for the solid catalysts. The catalyst concentrations were used in the range of 1% to 5%, for the sulfuric acid catalyst, and 0.01 to 0.05 g/cc, for the solid catalysts. The effect of temperature, catalyst concentration, agitation speed, size of catalyst particle and reactant concentration on the acetic acid conversion was investigated. A second-order kinetic rate equation was proposed to fit the experimental data. For both forward and backward reactions, the activation energies were estimated from Arrhenius plots. The reaction rate increased with catalyst concentration and temperature for both the liquid and solid catalysts. The acetic acid conversion was found to increase with increases in acetic acid to methanol ratio in the feed. The developed kinetic rate equation was used for the simulation of reactive distillation process, in our laboratory column.

Research paper thumbnail of Kinetics of esterification of methanol and acetic acid with mineral homogeneous acid catalyst

Chinese Journal of Chemical Engineering, 2015

Comparison of different kinetic models at 313 K and 0.3268 mol•L-1 catalyst concentration. Experi... more Comparison of different kinetic models at 313 K and 0.3268 mol•L-1 catalyst concentration. Experimental; Concentration based; activity based; Liu et al. [8]; Elugu et al. [9]; Bonnaillie et al. [15]; Agreda et al. [5] Catalysis, Kinetics and Reaction Engineering Kinetics of Esterification of Methanol and Acetic Acid with Mineral Homogeneous Acid

Research paper thumbnail of Developmental outcome of children with early transient thyroid hormone imbalances

Research paper thumbnail of Data on acetic acid–methanol–methyl acetate–water mixture analysised by dual packed column Gas Chromatography

Data in Brief

The composition of multicomponent determination by colorimetric titration is difficult. This comp... more The composition of multicomponent determination by colorimetric titration is difficult. This complexity is easily overcome by using Gas Chromatography technique instead of wet method for multi-component mixture analysis. In Gas Chromatography, first the standard chart is prepared by using the known amount sample concentration as the reference. Once calibration chart is prepared the unknown sample concentration easily measured by using the standard chart. In the present study a standard calibration chart developed for the four component system of acetic acid-methanol-methyl acetate-water. The samples were taken at various concentrations of all components and different chromatograms obtained under various concentrations respectively. The method of optimization was first carried out to get the sharp peaks of individual components and binary pairs also. By using those conditions, the multi components concentrations were estimated. From the present results, the area under gas chromatogram is linearly varying with mole% of the components compared to mass%.

Research paper thumbnail of Preparation of Ti Material Supported SBA-15 Functionalized with Sulfonic Acid Environmental Friendly Catalyst: Application for Esterification Process

Journal of Nanomaterials

Kinetics of catalytic esterification between propionic acid and n-butanol has been studied in a b... more Kinetics of catalytic esterification between propionic acid and n-butanol has been studied in a batch reactor by using a Ti-supported SBA-15 catalyst with sulfonic acid. The synthesized catalyst is used to test the efficacy of catalyst for esterification reaction. The SBA-15 acidity is tied to incorporation of Ti and -SO3H groups through and the use of Si/Ti with Si/S molar ratios. The results are mesoporous materials with a typical hexagonal structure of the Ti SBA-15 and wide areas and high pore diameters that are operated with sulfonic groups. The addition of SBA to Ti leads mainly to catalytic materials with Bronsted and Lewis acid sites. Ti SBA-15 is the most effective catalyst for sulfonic acid, with the highest consents of Lewis acid sites and deactivation resistance and low hydrophilicity. The effect of temperature, catalyst amount, and molar ratio on reaction kinetics has been studied. The conversion of propionic acid is found to be 91% at 115°C at a 2 : 1 ratio of n-butano...

Research paper thumbnail of Kinetic Modelling and Simulation Studies for the Esterification Process with Amberlyst 16 Resin

The reaction of methanol with acetic acid in a simple isothermal batch reactor was carried out to... more The reaction of methanol with acetic acid in a simple isothermal batch reactor was carried out to produce methyl acetate and water with and without catalyst. Amberlyst 16 used as the solid resin catalyst. The reaction mixture temperature was adjusted for 313.15 K - 353.15 K with and without Amberlyst 16. The concentration for catalyst changed from 0.048 mol H + /L - 0.24 mol H + /L based on volume of mixture. The reactant mole ratio for acid to alcohol was varied from 1:1 - 1:4. The influence of catalyst loading, reaction mixture temperature, initial reactant mole ratio, catalyst size, agitation speed on acetic acid conversion has been investigated. An experimental results show that reaction is kinetically controlled when compared to internal and external mass transfer effects. Kinetic rate equation of second order is used to fit experimental data. The reaction rate constants and activation energies were calculated from Arrhenius plot with and without catalyst. This equation ca...

Research paper thumbnail of Kinetic studies on esterification of acetic acid with isopropyl alcohol in presence of novel solid catalyst

The reaction of isopropyl alcohol with acetic acid was carried out in an isothermal batch reactor... more The reaction of isopropyl alcohol with acetic acid was carried out in an isothermal batch reactor in presence of solid resin catalyst to produce isopropyl acetate and water. A novel solid resin catalyst Indion 140 was used in the present study. The temperature of reaction mixture was maintained in the range of 333.15 – 363.15 K. The effects of reaction temperature, catalyst loading, mole ratio, size of catalyst, agitation speed were investigated on acetic acid conversion. Further, pseudo-homogeneous kinetic model was developed for the catalyzed reaction. The forward reaction rate constants and activation energies were determined from the Arrhenius plot. The forward and backward activation energies are found to 53,459 J/mol and 54,748 J/mol, respectively. The heat of reaction is −1.289 kJ/mol with Indion 140 catalyst. The mathematical equation was developed for frequency factor as function of the catalyst loading and found that it follows a linear relationship between frequency facto...

Research paper thumbnail of Pore diffusion model to predict the kinetics of heterogeneous catalytic esterification of acetic acid and methanol

Research paper thumbnail of Kinetics of esterification of acetic acid and methanol using Amberlyst 36 cation-exchange resin solid catalyst

Progress in Reaction Kinetics and Mechanism, 2015

Research paper thumbnail of Data on Conceptual design and Simulation of Reactive Distillation process

Data in Brief, Dec 1, 2019

Research paper thumbnail of Data on acetic acid–methanol–methyl acetate–water mixture analysised by dual packed column Gas Chromatography

Research paper thumbnail of Optimization Studies on Biosynthesis of Citric Acid by One-Factor-at-a-Time

Chemistry & Chemical Technology

In the presented study, the significant operating variables regarding biosynthesis of citric acid... more In the presented study, the significant operating variables regarding biosynthesis of citric acid process were assessed and their effects on the process yield were analysed. These variables, namely, initial sucrose concentration, methanol concentration, inoculum density, initial medium pH, spore age, stirrer speed, incubation period, fermentation temperature, particle size distribution, oxygen flow rate, and moisture content have significant influence on bioprocess of citric acid production. Plackett-Burman approach was used to determine the most significant variables, which predominantly influence the citric acid production process. Out of the eleven variables, initial sucrose concentration, initial medium pH, stirrer speed, incubation period, fermentation temperature, and oxygen flow rate were found to be significant. The effect of the significant variables on the yield of citric acid has been validated experimentally by one-factor-at-a-time empirical optimization technique. The optimum conditions have been determined. The effect of each variable on the yield of citric acid was analysed critically.