Ajit P. Rathod

Comparative study of different waste biomass for energy application

Biomass is available in many varieties, consisting of crops as well as its residues from agriculture, forestry, and the agro-industry. These different biomass find their way as freely available fuel in rural areas but are also responsible for air pollution. Emissions from such solid fuel combustion to indoor, regional and global air pollution largely depend on fuel types, combustion device, fuel properties, fuel moisture, amount of air supply for combustion and also on climatic conditions. In both economic and environment point of view, gasification constitutes an attractive alternative for the use of biomass as a fuel, than the combustion process. A large number of studies have been reported on a variety of biomass and agriculture residues for their possible use as renewable fuels. Considering the area specific agriculture residues and biomass availability and related transportation cost, it is important to explore various local biomass for their suitability as a fuel. Maharashtra (India) is the mainstay for the agriculture and therefore, produces a significant amount of waste biomass. The aim of the present research work is to analyze different local biomass wastes for their proximate analysis and calorific value to assess their potential as fuel. The biomass explored include cotton waste, leaf, soybean waste, wheat straw, rice straw, coconut coir, forest residues, etc. mainly due to their abundance. The calorific value and the proximate analysis of the different components of the biomass helped in assessing its potential for utilization in different industries. It is observed that ash content of these biomass species is quite low, while the volatile matter content is high as compared to Indian Coal. This may be appropriate for briquetting and thus can be used as a domestic fuel in biomass based gasifier cook stoves. Utilizing these biomass species as fuel in improved cook-stove and domestic gasifier cook-stoves would be a perspective step in the rural energy and environmental sectors. This is important considering that the cleaner fuel like LPG is still not available in rural areas of many parts of the world.

Comparative Study of the Mechanical and Thermal Properties of Polyamide-66 Filled with Commercial and Nano-Mg(OH)2 Particles

In the present work, polyamide-Mg(OH)2 nanocomposites were prepared via melt intercalation on a twin-screw extruder. Different particle sizes (24, 20, 11 nm) of Mg(OH)2 were synthesized by in-situ deposition technique and its shape and sizes was confirmed on transmission electron microscope (TEM). Nano-Mg(OH)2 was added from 1 to 4 wt% in the polyamide. Properties such as tensile strength, elongation at break, hardness, and flame retardency were studied. These results were then compared with commercial Mg(OH)2-filled composites. There was propounding effect to be observed on properties of polyamide nanocomposites due to uniform dispersion of nano-Mg(OH)2 and commercial Mg(OH)2. Moreover, thermal property like thermal degradation was studied on TGA. Extent of dispersion of nano-Mg(OH)2 was studied along with microcracks generated during tensile testing using AFM. It was found that nano-Mg(OH)2 is thermally more stable compared to that of commercial Mg(OH)2. Besides that, Tg and M.T. are studied on DSC.

Esterification of propionic acid with isopropyl alcohol over ion exchange resins: Optimization and kinetics

The esterification of propionic acid with isopropyl alcohol was studied in an isothermal batch reactor. The activities of three different types of ion exchange resin catalysts (Amberlyst 15, Amberlyst 70 and Dowex 50 WX8) were investigated, and Amberlyst 15 was found to be an effective catalyst for the reaction. The effects of process parameters, namely, catalyst loading, alcohol to acid molar ratio and reaction temperature, were studied and optimized. Response surface methodology (RSM) was applied to optimize the process parameters as well as to investigate the interaction between process parameters. The internal and external diffusion limitations were found to be absent at a stirring speed of 500 rpm. The RSM model predicted response (83.26%) was verified experimentally with a good agreement of experimental value (83.62±0.39%). Moreover, the kinetics was studied and the Langmuir-Hinshelwood model was used to fit the kinetic data.

Sonochemical synthesis of Graphene-Ce-TiO 2 and Graphene-Fe-TiO 2 ternary hybrid photocatalyst nanocomposite and its application in degradation of crystal violet dye

The present work deals with the preparation of graphene oxide (GO) using Hummers-Offeman method in the presence of ultrasonic irradiations. Further loading of TiO2 photocatalyst on prepared GO was accomplished which is basically oxidation reduction reaction between graphene oxide and titanium isopropoxide that leads to the formation of graphene-TiO2 nanocomposite. Graphene-Ce-TiO2 and Graphene-Fe-TiO2 nanocomposites were prepared using one step in-situ ultrasound assisted method using GO, titanium isopropoxide, cerium nitrate, ferric nitrate, and 2-propanol. The successfully prepared graphene-TiO2, Graphene-Ce-TiO2, Graphene-Fe-TiO2 nanocomposites were then characterized using XRD, SEM and TEM analysis. The obtained XRD patterns clearly indicates the formation of anatase TiO2 on graphene nanosheets and it also indicates the presence of Ce and Fe in the Graphene-Ce-TiO2 and Graphene-Fe-TiO2 nanocomposite respectively. Further the use of the prepared nanocomposites as a photocatalyst have been studied for the degradation of crystal violet dye. The effect of various parameters such as catalyst doping, catalyst loading and initial concentration of dye on its degradation were studied. The effectiveness of the prepared catalysts were compared for the degradation of crystal violet dye. It has been observed that Graphene-Fe-TiO2 exhibits maximum photocatalytic activity compared to Graphene-Ce-TiO2 and Graphene-TiO2 nanocomposite photocatalyst.

Enhancement of Esterification of Propionic Acid with Isopropyl Alcohol by Pervaporation Reactor

With increasing cost of raw materials and energy, there is an increasing inclination of chemical process industries toward new processes that result in lesser waste generation, greater efficiency, and substantial yield of the desired products. Esterification is a chemical reaction in which two reactants carboxylic acid and alcohol react to form an ester and water. This reaction is a reversible reaction and the equilibrium conversion can be altered by varying the process parameters. Pervaporation reactor can enhance the conversion by shifting the equilibrium of reversible esterification reactions. Polyvinyl alcohol-polyether sulfone composite hydrophilic membrane was used for pervaporation-assisted esterification of propionic acid with isopropyl alcohol. The experiments were carried out in the presence of sulphuric acid as a catalyst at 50°C to 80°C with various reactants ratios. The esterification was carried out for catalyst loadings of 0.089 kmol/m3 to 0.447 kmol/m3. The molar ratios of isopropyl to propionic acid used for the experiment were 1 to 1.5. Maximum conversion was obtained for the ratio of 1.4. Also effect of other parameters such as process temperature and catalyst concentration was discussed. It was found that the use of pervaporation reactor increased the conversion of the propionic acid considerably.

Process optimization and kinetic modeling for esterification of propionic acid with benzyl alcohol on ion-exchange resin catalyst

Benzyl propionate, an ester with floral and fruity odor, has significant applications in perfumery and flavor industries. This paper describes the optimization of the synthesis of benzyl propionate catalyzed by Amberlyst-15. The effects of various process parameters such as catalyst loading, alcohol-to-acid molar ratio and reaction temperature on propionic acid conversion and yield of ester were assessed by response surface methodology (RSM). The external and internal mass transfer limitations were found to be absent. Analysis of variance (ANOVA) showed that the acquired quadratic model successfully interpreted the experimental data with the coefficient of determination values, (R2>0.98) and adjusted R2 values, (>0.97). The RSM model was validated by good agreement between the model predicted and experimental values for responses. Pseudohomogeneous (PH) kinetic model was used and validated (R2>0.95) with the experimental data. The activation energy and frequency factor were evaluated as 42.07 kJ mol−1 and 19,874.64 L mol−1 min−1, respectively.

Response Surface Optimization and Kinetics of Isopropyl Palmitate Synthesis using Homogeneous Acid Catalyst

Abstract Fatty acid esters (FAE) are widely applied in the field of cosmetics, personal care products and various other allied applications. This work describes the synthesis of isopropyl palmitate (FAE) by esterification of palmitic acid with isopropyl alcohol catalyzed by p-toluene sulfonic acid (p-TSA) in a batch reactor. Response surface methodology (RSM) with Box-Behnken experimental design (BBD) was employed to design the experiments as well as to optimize the conversion of palmitic acid. The effects of various process parameters namely catalyst amount, molar ratio of alcohol to acid and reaction temperature on conversion of palmitic acid were evaluated. The high correlation coefficient (R2=0.973) between model and experimental data indicated that the data fitted well in the model. The optimal process conditions were found to be, catalyst amount of 5 % (wt/wt), molar ratio of alcohol to acid of 7:1 and temperature of 82 °C. Moreover, the kinetic model was developed at these optimized process conditions using second order kinetics and validated with experimental results. The kinetic model and experimental results were found to be in good agreement. The kinetic rate constants and equilibrium constant increased with increase in temperature. The activation energy and pre-exponential factor were found to be 45.21 kJ mol−1 and 1.96×105 L mol−1 h−1 respectively. The optimized process parameters obtained from RSM, equilibrium rate constants and the parameters evaluated from kinetic model may be useful for the simulation of pervaporation reactor and reactive distillation column for the synthesis of isopropyl palmitate.

Performance Study of Pervaporation Reactor (PVR) for Esterification of Acetic Acid with Ethanol

The most common reaction system studied for the application of pervaporation (PV) is an esterification reaction between alcohol and acid in the presence of a catalyst. In present paper, performance of pervaporation reactor (PVR) for esterification of acetic acid with ethanol was studied. Model equations were developed for reaction and separation in PVR. Model results were validated with experimental results and excellent comparison was obtained. The effect of various parameters such as: reactant ratio, ratio of effective membrane area to volume of reacting mixture, catalyst concentration and flux on the performance of PVR were discussed. The optimum conditions were obtained as: membrane area to volume of reacting mixture = 2 m-1, reactant ratio = 1.5, catalyst concentration = 50 g/l for esterification of acetic acid with ethanol in PVR. The model presented can also be used for the other esterification reactions. The described model allows the evolution of the reaction time necessary to achieve a given conversion. The process parameters: temperature, catalyst concentration, initial molar ratio of acid to alcohol, the ratio of the effective membrane area to the volume of reacting mixture can be changed in order to attain the optimum operating conditions of the pervaporation-esterification coupling operating.

Synthesis of cenosphere supported heterogeneous catalyst and its performance in esterification reaction

ABSTRACT A heterogeneous catalyst has been developed from cenosphere, a byproduct generated in thermal power plant. The performance of catalyst was investigated in the esterification of propionic acid and ethanol. The catalyst was characterized by FTIR, X-ray diffraction, field emission scanning electron microscope, and Brunauer–Emmett–Teller surface area and surface acidity analysis. The response surface methodology (RSM) with the Box–Behnken design was employed to design the experiments as well as to optimize the various process parameters such as catalyst loading, alcohol/acid molar ratio, and reaction temperature. The characterization revealed that the cenosphere supported catalyst possessed increased amounts of silica content, surface hydroxyl groups, surface area as well as surface acidity as compared with that of pristine cenosphere. The catalyst showed an excellent activity in the esterification reaction with a maximum conversion up to 91%. The RSM model well fitted the experimental data and predicted optimal conditions which were validated experimentally with a good agreement. The recyclability study showed a significant catalytic stability up to three reaction cycles. This study reveals that the cenosphere supported catalyst can be used as a potential catalyst in the esterification reaction may replace the conventional homogeneous acid catalyst.