Vellore Institute of Technology (VIT) is a private university located in&nbsp;Tamil Nadu, India. Founded in 1984, as Vellore Engineering College, the institution offers 20 undergraduate, 34 postgraduate, four integrated and four research programs. It has campuses in Vellore, Amravati, Bhopal and Chennai.

VIT is one of the top ranked private universities in India according to NIRF, THE and QS Rankings.&nbsp;Govt. of India has recognized&nbsp;VIT, Vellore as an&nbsp;Institution of Eminence. This has allowed VIT to take independent quality initiatives and move up in world ranking.

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VIT University

Background: Reusing waste water by appropriate treatment is an effective method for substantiating the ever increasing water demand for construction, irrigation, domestic and industrial purposes. The greywater is the domestic waste water that does not contain the toilet effluent and it is converted and used for non-potable purpose through coagulation and flocculation by using natural coagulant. Objective: The main objective of this work is to evaluate the coagulating efficiencies of various natural coagulants on synthetic greywater by varying pH, mixing speed, mixing time and coagulant dosage. Methods: Powdered coagulants obtained from tamarind seeds, moringa oleifera, banana peels and fly ash were compared with conventional commercial coagulants like alum for synthetic and real greywater. Results: The natural coagulants have shown significant performance compared to chemicals like alum. Conclusion: The turbidity removal efficiency for tamarind seeds, moringa oleifera, banana peels and fly ash were found to be 61.33%, 85.75%, 90.42%, 94.27% against 96.49% obtained from alum on treating with synthetic grey water under identical conditions. © 2020 Bentham Science Publishers.

Department of Chemical Engineering

School of Chemical Engineering

Vellore Campus

Recent Innovations in Chemical Engineering

Performance of Natural Coagulants on Greywater Treatment

Background: Solid suspension in liquids is an important unit operation generally encountered in the process industry. In the present work solid-liquid suspensions are explored in an agitated vessel with different liquids using two radial impellers namely Rushton turbine and straight blade; two axial impellers namely pitched blade turbine and A320. The critical impeller speed (Njs) at which all solid particles get suspended and the relevant power requirements (Pjs) are evaluated. The effect liquid viscosity on these two parameters is investigated. Conclusion: Results show that critical impeller speed and power consumption decreases as liquid viscosity increases. The critical impeller speed was found to be highest for straight blade impeller and lowest for pitched blade turbine. A320 impeller showed strong dependence of viscosity on critical impeller speed. In addition, the power consumption was found to be least for A320 impeller among the impellers investigated in this study.

Recent Innovations in Chemical Engineering (Formerly Recent Patents on Chemical Engineering)

The Effect of Liquid Viscosity on Critical Impeller Speed in an Agitated Vessel

Wellbeing and health is a standout amongst the most encouraging application territories of IoT innovation. Remote health management, managing lifestyle-related diseases and conditions, care at home, chronic diseases and care for the elderly are some of the important use cases. Other use cases include improving a patient’s compliance to treatment and medication in hospitals, clinics and other care facilities. Medical devices such as personal home-use diagnostic devices or low-end diagnostic and imaging devices that are used by mobile health workers are one of the key problems. Addressing of eHealth aims at launching an innovative mobile health care service supporting patients and health professional’s mobility, increasing patient’s quality of life and lowering health care costs. This paper shows an imaginative usage of an information securing, which can speak with a trunk belt keeping in mind the end goal to acquire the heart rate esteem and accelerometer information from an EZ Chronos watch. The fundamental objective of the work displayed is to execute an installed framework, which can be utilized as a part of different life helped or therapeutic applications. © IAEME Publication.

World University root node

International Journal of Mechanical Engineering and Technology

Wireless health acquisition system using internet of things

Lithium oxide (Li2O) has been suggested as a suitable breeder blanket material for fusion reactors. Li+ vacancies are created by neutron irradiation, forming bulk defect complex whose extra character is experimentally unclear. We present a theoretical study of Li2O using density functional theory (DFT) with a plane-wave basis set. The generalized gradient approximation (GGA) and local-density approximation (LDA) were used for exchange and correlation. Here we address the total energy for defect free, cation defect, cation vacancy and vacancy formation energy in Li2O crystal in anti-fluorite structure. © 2018 Author(s).

VIT Unitversity

Department of Physics

School of Advanced Sciences

AIP Conference Proceedings

Ab-initio calculation for cation vacancy formation energy in anti-fluorite structure

The successful design and operation of solid-liquid agitators require proper prediction of critical impeller speed (Njs) needed to suspend solids. It depends on system and impeller geometry as well as the properties of both solid and liquid. In this research, the effect of impeller blade thickness on Njs required for complete suspension of solid particles was discussed. Experiments were performed in an agitated vessel of 0.29 m diameter with three impellers namely Rushton turbine (RT), Pitched blade turbine (PBT) and A320 impeller. The impeller thickness was varied as 1, 2, 3 and 4 mm. The results showed that with the increase in impeller blade thickness, the critical impeller speed decreased significantly and the power required for complete suspension increased. Modifications are made in the Zwietering correlation by considering the effect of the impeller blade thickness to improve the prediction of critical impeller speed. © 2017 ALMA MATER Publishing House, “VASILE ALECSANDRI” University of Bacău. All rights reserved.

Scientific Study and Research: Chemistry and Chemical Engineering, Biotechnology, Food Industry

Effect of impeller blade thickness on critical impeller speed in an agitated vessel

The effect of impeller clearance and liquid level on the critical impeller speed (Njs) for various radial and axial flow impellers in 0.29 m ID agitated vessel has been studied. Five types of radial impellers: Rushton turbine (RT), Straight blade (SB), Curved blade (CB), Curved blade with disc (CBWD) and R130 impeller and four types of axial impellers: Rushton turbine 45o angle (RT 45), Pitched blade (PBT), A320 and HE3 impeller were used. Tap water and resin particle of 0.506 mm were used as liquid and solid phases, respectively. The impeller clearance to vessel diameter (T) was varied between 0.17 and 0.41. The liquid level (H) was also varied as H/T=0.5, H/T=0.75 and H/T=1. The R130 impeller and A320 impeller was found to be more efficient among radial and axial impellers respectively. A new expression for Zwietering constant 'S' was developed to predict critical impeller speed, considering impeller clearance and liquid level for all the impellers. The results obtained here show that the 'S' values increase with increase in clearance, and decrease with liquid level for all impellers and it also depends on the type of impeller.

Fulltext

Journal of Applied Fluid Mechanics

Effect of Impeller Clearance and Liquid Level on Critical Impeller Speed in an Agitated Vessel using Different Axial and Radial Impellers

The effect of impeller blade width on the critical impeller speed (Njs) for the suspension of solid particles has been studied in a flat-bottomed agitated vessel of inside diameter 0.29 m. Tap water and resin particle of 0.506 mm are used as liquid and solid phases respectively. The solid loading was 5 % by volume. In this study, the following three impellers were employed, namely Rushton turbine, pitched blade turbine and A320 impellers. The ratio of impeller width to vessel diameter was varied in the range of 0.21 to 0.41. The ratio of impeller clearance to vessel diameter was varied in the range of 0.17 to 0.41. With the increase in impeller blade width, the critical impeller speed initially decreases to a minimum value and then increases with the impeller blade width. The A320 impeller was found to be more energy efficient than pitched blade turbine and Rushton turbine impellers. The impeller blade width has a more significant effect on the critical impeller speed of A320 impeller. Pitched blade turbine shows that the strong dependence of impeller clearance on critical impeller speed. A modified Zwietering correlation has been proposed for the estimation of critical impeller speed as a function of impeller blade width, which is expected to be useful in design. © Research India Publications.

International Journal of Applied Engineering Research

Effect of impeller blade width on critical impeller speed in a flat-bottomed agitated vessel

Agitation finds its usage among a wide range of industries like food, cosmetic, chemical, biochemical and pharmaceutical applications. Among chemical applications these include fermentation, crystallization, hydrogenation and catalytic reactions. The determination of critical impeller speed is one of the most important parameter under consideration for mechanical agitators and has been under investigation for quite some time now. However, the effect of impeller clearance for different impellers on solid mixing has not yet been well established. In this work, three impellers have been taken into consideration, namely, Rushton turbine, Rushton turbine with 45° angle and Pitched blade turbine. An attempt has been done to study the effect of multiple impeller combinations in a standard agitated vessel. The impellers were used individually and in combinations of two and three. The critical impeller speed, optimum impeller clearance and power consumption were observed. Hick's method was used to determine the critical impeller speed and the power consumption was determined by using a piezoelectric ceramic transducer and the experiments were performed in the C/T range of 0.1 to 0.35.The study revealed that at a clearance of T/3 all the three impellers showed lowest critical impeller speed and pitched blade turbine consumes less power compared to other impellers. In two impeller combinations the Rushton turbine at the bottom and pitched blade at the top consumed less power among other two impeller combinations. In three impeller combinations the Rushton turbine at bottom, pitched blade at middle and Rushton turbine with 45° angle at top consumed less power among other three impeller combinations.

International Journal of ChemTech Research

Effect of impeller clearance and multiple impeller combinations on solid suspension in a standard flat bottom agitated vessel

In the present work two mixing operations, adsorption and decomposition of carcinogenic methylene blue were performed in a flat bottomed mechanically agitated tank with a six-blade Rushton turbine (6DT) and a Pitched blade turbine (PBT). Both the operations were carried at Njs, which is the key process objective to make all the surface area of the solids available for mass transfer. The first operation involves the adsorption of eosin dye on Granular Activated Charcoal (GAC), which resulted in a 67% color removal. This work would help in designing systems for wastewater treatment. The second operation involves the photo catalytic effect of TiO2 on methylene blue to decompose it into carbon dioxide and water, which resulted in a 62.3% degradation of methylene blue. The work can be adopted by the textile industry in order to reduce the carcinogenic content of effluents, thus making it less of a health hazard. In both the cases, it is inferred that power required for a Pitched Blade turbine is significantly lower than that of Rushton turbine, also there is a linear rise in power required with increase in solid volume percent. © 2014, Sphinx Knowledge House. All rights reserved.

Effect of solid concentration and impeller type on mixing operations in an agitated vessel

Computational Fluid Dynamics (CFD) studies in a baffled stirred tank agitated by six bladed turbine rotating at 300 rpm is reported in this paper. This work is concerned with the effect of small range of particle size and particle density on solid concentration distribution in a baffled tank agitated vessel stirred with Rushton turbine. The system studied consisted of a cylindrical flat bottom tank, 294 mm in diameter, with six blades Rushton turbine, 98 mm in diameter, filled with water. Baffle width is 0.1 tank diameter and the impeller clearance is 0.3 tank diameter from the tank bottom. The height of liquid level in the tank is equal to tank diameter. The solid concentration was analyzed for different suspensions sand, granite, silica and quartz of different diameters 500 μm, 650 μm, 920 μm and 1100 μm using CFD tool CFX 12.0. A classical Eulerian- Eulerian two fluids model and the standard k- ε turbulence model were used to simulate the suspension behavior. In this work, the solid concentration distribution was predicted using frozen rotor steady state approach. It was observed that the solid concentration in the radial direction is similar for different particle sizes except near the wall and it was same for different density particles which is considered in this paper. Also the solid concentration in the axial direction had similar pattern for different density particles and different sizes. It is found that the solid volume fraction is decreases with increase in particle size and density at all heights in radial direction and it is more significant at higher suspension levels. The study revealed that non uniformity in solid concentration is viewed both in radial and axial direction at this speed for this close range of particle sizes and densities.