Application of Response Surface Methodology for Effective Recovery of Indian Coking Coal Fines Through Froth Flotation Technique G. V. S. Sarma, A. Kumar Sanjay, K. Sarath Chandra, G. M. J. Raju, K. V. Ramesh, et al. Journal of the Institution of Engineers India Series D, 2022 Samples of the coking coal fines from the settling ponds of the nearby washeries were collected and tested for their cleaning potentialities by conducting systematic beneficiation studies. Response surface methodology (RSM) with central composite design was employed to optimize the input variables by maintaining other parameters constant to get maximum yield of clean coal. A second-order regression equation that resulted from two-factor interaction (2FI) method was found to be the most appropriate one to correlate experimental data. The analysis of suitability of selected model of the present experimental data was substantiated by the correlation coefficient value of 0.8815. Lower values of coefficient of variance (CV) also supported the model fitness to experimental design. Higher values of efficiency index, separation index, rate constant and separation efficiency rates are additional parameters that supported the performance of the frother. The optimum dosages of collector and frother were found to be 0.8 ml and 80 ml respectively for obtaining maximum yield of clean coal.
Effect of fluidizing solids on wall-liquid mass transfer in a cylindrical cell with rotating central rod G. M. J. Raju, G. V. S. Sarma, K. V. Ramesh, C. Bhaskara Sarma Heat and Mass Transfer Waerme Und Stoffuebertragung, 2021 Limiting current density data were obtained at point electrodes fixed flush with inner surface of the outer cylinder of an electrochemical cell in which a coaxially placed cylindrical rod is rotated at different rotational velocities in the presence of fluidizing solids. The variables covered in the present study are rpm of inner annular rod, diameter of rod, solid fraction and flow rate of the electrolyte. Mass transfer coefficients, which were computed from limiting current density data, were found to increase with an increase in the velocity of the fluid electrolyte through the annular cell in the presence of fluidizing solids. No specific trend was observed with respect to the rpm of the central annular rod. The variation in mass transfer coefficient values due to change in the rod diameter was just marginal. The bed expansion data represented Richardson-Zaki equation with an exponent of 2.15. Colburn jD-factor format has been used to correlate the data on mass transfer coefficients.
Kinetic studies of esterification of butanoic acid with cyclohexanol G.V.S. Sarma, G.V. Santosh Kumar, M. Vijay, K.V. Ramesh Materials Today Proceedings, 2021 Kinetic studies of esterification of butanoic acid with cyclohexanol were carried out using sulplhuric acid as catalyst. Experiments were conducted in a stirred, temperature controlled batch reactor. The reaction is homogeneous. The effects of different variables that influence the rate constant such as temperature, catalyst concentration and mole ratio of reactants were studied. The reaction rate followed second order with respect to the acid concentration. The mole ratio is varied between 0.5 and 2.0, temperature between 50 and 70 °C and catalyst concentration between 0.5 and 1.5 wt%. An equation is obtained for the prediction of rate constant.
Mass transfer at the confining wall of an electrochemical cell in annular flow with a rotating central rod G. M. Jagannadha Raju, G. V. S. Sarma, K. V. Ramesh, C. Bhaskara Sarma Indian Chemical Engineer, 2021 An electrochemical method (limiting current technique) was used to obtain mass transfer coefficient (k L) in a flow reactor in which the coaxial inner cylindrical rod was rotated at different revolutions per minute (rpm). The effect of liquid velocity, rpm and rod diameter on the liquid-wall mass transfer coefficient was investigated. It was observed that at any given rpm, the k L increased with the liquid velocity. Rotation of the central rod was found to further augment the coefficient. Augmentations were found to be more significant at small liquid velocities. The effect of central (annular) rod diameter was also studied and the k L data were correlated using Colburn j-factor format. GRAPHICAL ABSTRACT
Modified Laterite Adsorbent for Cadmium Removal from Wastewater Kothamuri Sudha Rani, Goruganthula Venkata Subrahmanya Sarma, Karri Gouru Naidu, Kasala Venkata Ramesh Journal of the Institution of Engineers India Series D, 2020 Being a toxic metal, the presence of cadmium in water leads to damage of health in human beings. Effluents from various processes and industries inevitably contain cadmium as remnant, and its removal is necessary to meet with the existing statutory norms. So far, many adsorbents are used in the industry, but most of them are rather costly. Therefore, a cheaper and effective adsorbent, modified laterite is used in the present investigation as an alternative. Batch studies are conducted to elicit information on operating variables (pH, temperature, adsorbent dosage, initial concentration and contact time). In the present study, optimum values for these variables are reported as 7.0, 30 °C, 6 g/L, 100 mg/L and 30 min, respectively. Maximum cadmium uptake obtained was 100 mg/g. The kinetic data were in good agreement with pseudo-second-order model. Also Langmuir, Freundlich and Temkin isotherms were obeyed. From thermodynamic calculations, a change in enthalpy was found to be 170 J/mol.
Potential removal of phenol using modified laterite adsorbent Indian Journal of Biochemistry and Biophysics, 2020