Chemical Engineering

While oil prices continue to climb, energy conservation remains the prime concern for many process industries. The challenge every process engineer faced is to seek the answer to questions related to their process energy pattern. Distillation column are of great importance in process analysis as they are the most common and the most energy intensive separation systems and hence it is the first separation system to be analyzed specifically from a pinch view point. In this paper heat integration of crude organic distillation unit has been done using pinch technology. Pinch Technology involves composite curves, problem table algorithm and heat exchanger network design. Using targeting procedures, hot and cold utility reduction occurs. With this design, cost estimation has been done using heat exchanger cost equation. Although the results found can be used for development of new projects, as heuristics rules, the application has been limited due to lack of understanding of the subject

Pressure swing distillation (PSD) is a technique coming forward as a strong alternative to the conventional separation methods for separating azeotropes. The conventional pressure swing distillation involves two columns operated at two different pressures. This work puts forward a new three column oressure swing distillation strategy for the separation of azeotropic Isobutyl Alcohol (IBA) Isobutyl Acetate (IBAc) mixture. Two of the columns are operated at atmospheric pressure while third at a lower pressure. CHEMCAD (version 6.5) software is used to perform the simulations to get the optimized configuration which gives minimum energy requirements. The proposed process comes out to be more energy efficient when compared to the conventional two column techniques.

A nanofluid is mixture of nano sized particles and a base fluid. This paper investigates by using laboratory based double pipe heat exchanger model, the performance of nanofluid containing about 48.46nm particle size nanoparticles (ZnO) without or with addition of nonionic surfactant Rokanol K7 (500ppm) into the base fluid double distilled water to prepared three different concentrations 1.0%, 2% and 3% (v/v) of ZnOwater or ZnO-RK7. Effects of temperature and concentration of nanoparticles on viscosity and heat transfer coefficient in heat exchanger are investigated. The experimental results shows that the viscosity of nanofluids increased with increasing concentration of fluid whereas decreased with increasing temperature from 20 to 60ºC. However, it has been also observed that heat transfer coefficient increases with the operating temperature and concentration of nanoparticles. The conclusion derived for the study is that overall heat transfer coefficient enhanced with increasing concentration upto 3% of ZnO-RK7 as compared to without surfactant nanofluids.

The present phenomenon, i.e. enhancement of mass transfer coefficient in liquid-liquid extraction operation is a complex one and it cannot be reasoned out by any logic based model, so it is find out by experimental data based model. The present investigation is focused on the behaviour of nanofluid in the liquid-liquid extraction process. The chemical system of toluene-acetic acid-water was used, and nanofluids containing 0.1%, 0.2% and 0.3% (V/V) of zinc oxide nanoparticles of size 48.79 nm synthesised by chemical precipitation method. Maximum enhancements in the rate of mass transfer of were achieved using about 0.3 wt% zinc oxide based nanofluids; however, a decreasing variation was observed at higher concentrations. The effect of nonionic surfactants Rokanol K7 (500 ppm) on mass transfer of the liquid-liquid extraction process was also investigated and it was observed that the mass transfer coefficient increases rapidly with surfactants under a varying speed of agitation but deteriorates at high concentration. The formulation of approximate generalised experimental data based model has been developed followed by interpretation and the quantitative analysis of the model. For the aim of modelling, the experimental results obtained from liquid-liquid extraction were validated with mathematical modelling for calculation of reliability of model.

The Proton Exchange Membrane Fuel Cell (PEMFC) is a promising candidate as zeroemission alternative power source for transport & stationary application due to its high efficiency ,low temperature operation ,high power density ,quick start-up and system robustness. In this paper, under the condition of steady state and flow in cell is considered to be laminar, the performance of 300w &100w PEMFC stack has been studied.300w fuel cell is compact &100w fuel cell is openable. This cell is self-humidified. Series of polarisation curves with different loading of voltage have been studied. various values of voltage, current density, power density &related temperature have been recorded using lab VIEW software. For this class of fuel cell, optimal operating temperature is found to be 75 0 c at 0.3v loading.the results obtained would lead to improvements in the design of fuel cell.

In this paper, performance of Catalyst Coated Membrane (CCM) has been studied. Effect of various parameters on current density and power density has been analysed. Observations has been depicted using polarisation as well as power curves. CCM always gives better performance as catalyst it has direct ionic contact with membrane. CCM manufactured by Paxitech fuel cells, France has been used to perform the experiment along with stack fabricated. It is prepared with catalyst coating of 0.5mgPt/cm2 by ultrasonic spray coating method. The SEM analysis has been carried out to study morphological characteristics of CCM. Out of other parameters, hydrogen humidification and air stoichiometry have good effect on CCM performance. Maximum current density obtained was 1.28A/cm2 with hydrogen humidification temperature as 550C. The performance has been analysed by polarization curve, Description of various parameters has been given in detail.

In the last decades, fuel cells are exceptionally capable and environmentally responsive energy exchange devices and have received great attention for the energy investigation. The components of fuel cells and its fabrication techniques essentially affect the performance of fuel cell. The gas diffusion electrode (GDE) is considered to be one of the key components of PEMFC. In the present work, hot pressing technique has been used for the fabrication of GDEs and were studied in detail. The catalyst loadings of 0.25, 0.5 and 2 mgPt/cm 2 with different charging of carbon were layered on the surface of GDL opposite the membrane and its performance are correlated by using two different oxidants i.e. air and oxygen. The fuel cell performances have been compared by using performance curve at different cell stack temperature. The optimum catalyst loading for highest current density and power density was found to be 0.25 mgPt/cm 2 on anode side and 0.5 mgPt/cm 2 on cathode side. Surface quality of these GDLs have been investigated with the help of scanning electron microscopic (SEM) analysis by performing top surface and crosssectional scan and confirms the effectiveness of hot-pressing method for better quality catalyst.

The present work reports sonochemical preparation of zinc oxide (ZnO) and silver decorated ZnO (9 wt%) with the use of zinc acetate, silver nitrate and sodium carbonate as precursors in 60 min duration. The resulted ZnO and silver decorated ZnO nanoparticles were characterized with SEM, FE-SEM, FTIR, XRD and UV-Vis techniques. XRD analysis reveals hexagonal quartzite crystalline phase of ZnO with highest purity. The doping of silver differs the ionic radii of the elements and that produces the strain in Ag-ZnO nanocomposites. The average crystallite size of ZnO and Ag-ZnO estimated to be 17.53 and 18.73 nm, respectively with the use of XRD analysis. The lattice parameters, crystallite size and unit cell volume was observed to be increased with the loading of Ag on ZnO nanoparticles during its preparation with the aid of ultrasonic irradiations. The observed lesser size of nanoparticles and nanocomposites is due to the use of ultrasonic irradiations. Photocatalytic properties of ZnO and Ag-ZnO (doped) nanocomposite was examined for the degradation of methylene blue (MB) dye in aqueous solution under solar light irradiations. Influence of the initial dye concentration, catalyst loading, pH, and temperature on the degradation of MB dye was investigated and optimized conditions were obtained. Furthermore, a relative study of photocatalytic properties of ZnO and Silver doped ZnO nanocomposites prepared by conventional and sonication method was accomplished and the results were discussed. A maximum degradation of MB dyes was achieved (~96.2%) under optimized conditions for Ag doped ZnO nanocomposite prepared by ultrasound assisted method.

Trans-aconitic acid (Propene-1 2 3-tricarboxylic acid) is an organic acid and is generally found in sugar cane. It is used as accidulent in food industry and can be used in synthesis of plasticizers. It is widely used in tissue engineering application. The present work focused on extraction of Trans-aconitic acid from its aqueous solution by using Aliquat 336 using natural non toxic diluents like Sunflower oil, Groundnut oil and Rice bran oil. Physical extraction and chemical extraction has been done to find out equilibrium parameters such as distribution constant, degree of extraction, loading ratio and equilibrium complexion constant. The experimental results are distribution coefficient (sunflower oil (2.81), groundnut oil (2.80) and for Rice oil (2.92), degree of extraction (56 to 81% for sunflower oil, 59 to 86% for groundnut oil, 58 to 82 % for Rice bran oil), loading ratio (< 0.5) and equilibrium complexation constant 1.1152 l/gm equi for Sunflower oil, 1.6128 l/gm equi for groundnut oil and 4.5556 l/gm equi for Rice Bran Oil. Water co extraction has also been studied, not more than 3%.

Reactive extraction of Trans-aconitic acid from its aqueous solution has been carried out by Tributylphosphate as extractant and benzene, xylene as diluents. The study has been performed at room temperature and distribution coefficient (KD), extraction efficiency (E %) and equilibrium complexation constant (K11) has been found out. The maximum value of KD = 9.098454, E%=90.09749 was found out for 0.689219 mol/L trans-aconitic acid, 1.40733mol/L (40%) Tri-butylphosphate and benzene. The paper has presented linear solvation energy Relationship (LSER) model for trans-aconitic acid using tri-butyl phosphate in benzene, xylene.The LSER model with regression coefficient of 0.9845 is obtained. The model value is close to the experimental data.

The detailed investigation of the chemical structure of vitrinite-rich Karharbari coal was performed utilizing advanced analytical techniques. The salient objective of this work is the evaluation of various structural properties of coal, which is necessary for identifying the chemical and physical interactions between coal and various reactants during its utilization. Karharbari coal is a poorly organized coal with high aromatic content. The value of corrected aromaticity (f a ') was found to be 0.82 by 13 C NMR spectroscopy and was also confirmed by XRD (aromaticity = 0.84) and FT-IR analysis (aromaticity = 0.82). The average molecular weight of the aromatic cluster was found to be 507 amu by the NMR result, which is closer to the result obtained by HRTEM (MW = 530 amu). The structural and lattice parameters of Karharbari coal were obtained by NMR spectroscopy and then compared with the similar rank Argonne Premium coal. The molecular weight distribution was obtained by LD-TOF-MS and compared with HRTEM fringe model analysis. The presence of different heteroatoms like carbon, oxygen, nitrogen, and sulfur with their functionalities was determined by using the XPS technique. Different carbon/oxygen functionalities present in the Karharbari coal were found to be (C−C) and (C−H) 68.5%, (C−O) 23.4%, (COO −) 1.9%, and (CO) 6.0%. Nitrogen functionalities such as pyridine, pyrrolic, quaternary, and oxidized nitrogen and their compositions (mol %) were 19.3, 45.6, 31.2, and 3.7%, respectively. Different forms of sulfur were also found to be present, namely, thiophenes, sulfones, sulfuric acid, and sulfates with the molar contents of 16.4, 41.6, 21.3, and 20.5%, respectively. This information will be useful in improvising coal utilization techniques.

Groundwater has become an alternative source for domestic and irrigational uses at present in most places, due to insufficient availability of clean surface water. Limited availability and supply of potable water, people have started using groundwater for drinking and other domestic purposes. This study was aimed to estimate physico-chemical properties in ground water samples collected from different sources around coal mines of Dhanbad. A total number of 25 ground water samples have been collected during the post monsoon season (October, 2015-December, 2015). This study reveals that physico-chemical properties like pH, TDS, Alkalinity, Total Hardness, Chloride, Sulphate, Nitrate, Fluoride, Iron and Zinc showed considerable variation due to metamorphic impact but were found within the permissible limit prescribed by IS 10500: 2012 Second Revision. Water Quality index (WQI) value ranged from 23.9 to 260.3. It showed that 48% of the water samples fall in the category of good water and 52% of the water sample falls in the category of poor water which were due to elevated iron content but fall under good water characteristics considering other parameters. The ground water for use of drinking purpose requires some treatment including removal of Iron.