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Studies on the Thermal and Morphological Characteristics of Laminates Based on Vinyl Ester Resin and Glass fabric

Studies on the Thermal and Morphological Characteristics of Laminates Based on Vinyl Ester Resin and Glass ...

Simulation of CO2 Capture Process From Coal Fired Power Plant Integrating the Absorption Process and Steam cycle

Simulation of CO2 Capture Process From Coal Fired Power Plant Integrating the Absorption Process and Steam ...

Refinery Configuration Studies on Indigenous and Imported Crude Oils

Re Engineering the Process in Plant Scale Production of Ammonium Uranate Using Vapour Ammonia as a Precipitation reagent

Re Engineering the Process in Plant Scale Production of Ammonium Uranate Using Vapour Ammonia as a Precipit...

Physico-Chemical Properties of Oil Extracted From Custard Apple (Annona Squamosha Seeds

Performance Assessment of Plant-Wide Control Systems

PACKING MATERIAL FOR ABSORPTION TOWER IN SODIUM NITRITE PLANT, RCF EXPERIENCE

Ozonation of dye in a fixed bed batch bubble column reactor-a case study

Ozonation of dye in a fixed bed batch bubble column reactor-a case study for the removal of persistent che...

IP (Intellectual Property) Means to Enhance Performance Factors (Cost, Quality & Speed) in R&D

Foam Characterization Using Glass Coker Experimental Set Up

Comparative analysis of demineralization on Indian Coals

Advanced Techniques for Measurement of Heavy Metal Concentrations From Seawater

Electrochemical degradation of textile dye using airlift type electrochemical reactor

Textile wastewater is characterized by strong color, large amount of suspended and dissolved solids, broadly fluctuating pH, high chemical oxygen demand (COD) and bio-toxicity. Physico-chemical treatments such as coagulation, adsorption, and other processes generate secondary pollutants. Advanced oxidation processes are efficient in decolorizing dye containing effluents but often they are preferred due to their high investment and operational cost. Therefore such processes can be used as pretreatment before biological treatment to make the pollutants bio-amenable. Electrochemical methods are used successfully for the degradation of dyes and treatment of textile industry wastewater. This study presents the electrochemical degradation of dye containing effluents by airlift type electrochemical. Granulated activated carbon and stainless steel was used as an anode and cathode, respectively. Chemical oxygen demand (COD), color and toxicity reduction during electrochemical degradation was monitored. The experimental results showed that the removal efficiency was as much higher as 94% in the investigated time of 30 min to 1 h, which is normally efficient for industrial level processing. Further, influence of initial concentration of dye and pH on degradation of dye was studied.

Key words: COD removal, Dye wastewater, Airlift type electrochemical bipolar reactor

Evaluation of electrochemical and mechanical properties of composite bipolar plate for acid and alkaline fuel cells

Proton exchange membrane fuel cell (PEMFC) is one of the most promising clean energy sources for residential and automotive applications due to its attractive features such as high power density, relatively low operating temperature, convenient fuel supply, longer lifetime, modular in shape etc. [1,2]. Bipolar plate is one of the most important components of low temperature fuel cell, which contributes to about 80% of the total weight of the PEMFC stack [3,4]. Recent cost analysis shows that 38% of the total cost of the PEMFC stack is incurred by the bipolar plate followed by the cost of electrodes, membrane, and catalyst as 32, 12 and 11%, respectively [4]. Different type of materials like metal sheet, polymer coated metal sheet, graphite, flexible graphite, C-C composite, advanced composites etc. are under investigation for the development of low cost and low weight bipolar plates [3-5].

Composite bipolar plates for proton exchange membrane fuel cell were prepared by compression molding technique using novolac type phenol formaldehyde resin as a binder and natural graphite, carbon black and carbon fiber as reinforcements. The effects of different reinforcements on the properties of composite bipolar plate were studied. The bipolar plates were characterized for electrical conductivity, mechanical strength and corrosion resistance. The optimum flexural strength of the composite bipolar plate was 55.28 MPa, with a deflection of 5.2% at mid-span, while the in-plane and through-plane electrical conductivities were 285.54 and 91.79 S·cm^-1, respectively. Corrosion analysis of the bipolar plates conducted in simulated fuel cell environment showed significantly high corrosion resistance or low current density, which made it suitable for proton exchange membrane fuel cell. The corrosion current density of the bipolar plate for the optimum composition was 0.245µA∙cm^-2 at 0.004V corrosion potential with respect to standard hydrogen electrode. Moreover, corrosion analysis in alkaline solution also showed that the developed bipolar plate had a potential scope for use in alkaline fuel cell.

Keywords: Bipolar plate; Corrosion; Fuel Cell; Phenolic Resin; Reinforcement

Experimental studies of sugar effluent by electrochemical – oxidation in batch reactor using artificial neural network and response surface methods

The Experimental studies of sugar effluent by electrochemical – oxidation in Batch reactor using Artificial Neural Network and Response Surface Methods” elucidates the reduction of organics in sugar effluents through electrochemical oxidation technique. Effect of parameters such as current density and mediator concentration on % COD reduction and power consumption for batch reactor without recirculation and the influence of current density, volume and flow rate on % COD reduction, power consumption, mass flux and rate constant for batch reactor with recirculation has been studied and analyzed.

It was found out that, the % COD removal efficiency can be improved by the addition of mediator (NaCl). The maximum % COD reduction of 80.74 % was achieved at current density of 5 A/dm²and 5 gpl of mediator concentration for Batch reactor. A maximum % COD reduction of 64.28 was achieved at flow rate 20 lph, current density 3 A/dm^2, Volume 5 litre for batch reactor with recirculation. Artificial neural network has been used to simulate the batch reactor without recirculation results and the predicted values are then compared with the experimental values. Response surface methodology has been used to study the effects of various parameters on % COD reduction, power consumption and mass flux for batch reactor with recirculation and quadratic models have been generated.

Ethanol & fuel cell – converging paths of opportunity

The energy challenges facing our Nation offer tremendous opportunities for agriculture and technology. For example, by combining fuels such a ethanol with fuel cells, farmers can be energy producers as well a consumers. Meanwhile, the US is under increasing pressure to reduce greenhouse gas emissions. Recent energy supply crunches and price spikes have once again focused attention on the need to improve energy security, increase and diversify domestic energy supplies, ensure environmental quality, and modernize the nation’s energy infrastructure. Ultimately, America’s economic prosperity and national security depend on the availability of reliable, affordable energy. This paper presents a vision of how ethanol and fuel cells can be combined to create significant synergy, reaching markets and bringing benefits that are not achievable with any other fuel or with any other power technology. In the pages ahead, we will describe these benefits and present a roadmap for how these synergies can be developed in an effective and stepwise fashion through contributions from the ethanol, fuel cell, automotive, and utility industries along with support from state and federal governments. The basis or platform for this vision is the existing, ongoing investment in ethanol and fuel cell markets, which has already been committed by government and industry.

Parametric studies of a polymer electrolyte membrane fuel cell (PEMFC) cathode

A two-dimensional two-phase steady state model of a Polymer Electrolyte Membrane Fuel Cell (PEMFC) cathode is developed to study the effects of various operating, design, and model parameters on the cell performance. The model domain consists of the cathode flow field, two layers of diffusion medium, catalyst layer, and the polymer membrane. In this work, the catalyst layer is modeled using flooded spherical agglomerate characterization. An expression is developed for the void fraction of the catalyst layer in terms of its design parameters. The developed model is validated with experimental data available in open literature. The effects of various operational parameters such as cell temperature, pressure, and the cathode air flow rate are studied in detail. The effects of the design parameters of the parallel flow field geometry and that of the diffusion medium are observed. In addition, the role of electric conductivity of the gas diffusion layer (GDL) on the cell current density is studied. Many limiting mechanisms take place in the cathode catalyst layer. Therefore, special emphasis is given on the parametric study of the catalyst layer. The effects of the catalyst layer design parameters such as the thickness, and the loadings of platinum and ionomer are studied. Finally, the issues related to water management are studied.

The effects of liquid water are considered in all the porous layers. Both electro-osmotic drag and back diffusion are considered for transport of liquid water in the membrane. The importance of modeling the membrane for capturing the cell performance is shown by simulating the effects of low concentration gradient of water in the membrane. The study on operating conditions showed that the optimum operating temperature of the cell is 80°C - 85°C and the performance of the cell is better at high pressures and flow rates. The study on design parameters suggests that the optimum porosity of the GDL for this cell is in the range of 0.7 to 0.8 and a thinner catalyst layer with high platinum and membrane content performs better than other combinations considered in this study. The detailed parametric study considering the effects of liquid water provides a pathway for different optimization studies in various layers.

Influence of Ca3(PO4)2 on the electrochemical properties of Poly (ethylene oxide)/LiN(CF3SO¬)2 - based nanocomposite electrolytes for lithium batteries

The development of polymer electrolytes has long been the subject of research interest due to their potential applications not only in the area of rechargeable lithium batteries but also in other electrochemical devices. In the present study nanocomposite polymer electrolytes (NCPE’s) comprising poly(ethylene oxide), Ca₃(PO₄)₂ and LiClO₄/LiN(CF₃SO₂)₂ in varying proportions are prepared by a hot press method. The nanosized calcium phosphate filler particles were synthesized using in situ deposition technique in the presence of poly ethylene oxide (PEO) as follows: Firstly, a complex of calcium chloride with PEO was prepared in desired proportions in methanol. An appropriate stoichiometric amount of trisodium phosphate, Na₃(PO₄) in distilled water was added to the above complex slowly without stirring. The whole mixture was allowed to digest at room temperature for 24h when both the chloride and phosphate ions diffused through the PEO and formed a white gel like precipitate, which was filtered, washed and dried.

The membranes were characterized by SEM, DSC, TG-DTA, ionic conductivity and transference number studies. The evolution of interfacial resistance as a function of time is followed with Li/NCPE/Li symmetric cells at 80°C under open- circuit conditions. This paper also describes FTIR spectroscopic studies of the interface between lithium metal and NCPE, which suggests that the surface chemistry of lithium electrodes in contact with NCPE is dominated by compounds with Li₃PO₄ bonding. The free volume (V_f) of the membranes is probed by positron annihilation lifetime spectroscopy at 30°C and the results support ionic conductivity data. The NCPE’s with LiClO₄ exhibits higher ionic conductivity than that of NCPE with LiN(CF₃SO₂)₂ (LiTFSI) as salt.

References

[1] A. Manuel Stephan, T. Prem Kumar, M.Anbu Kulandainathan, N. Angulakshmi

J. Phys. Chem. B 113 (2009)

[2] A. Manuel Stephan, Eur. Polym. J. 41 (2006) 21-42

Lithium insertion behaviour of nanoscopic Co3O4 prepared with avian egg membrane as a template

Conventional wisdom on electrochemical insertion reactions requires electronically conducting electrode materials with crystallographic voids that can support lithium diffusion. In that sense, interstitial-free 3d-metal oxide structures are considered unsuitable for intercalation chemistry. However, recently, Tarascon et al. [1,2] demonstrated the use of several oxides, nitrides, fluorides, phosphides, sulphides and borides as anode materials for lithium-ion battery chemistry. They described the associated reactions, which can involve as many as four electrons per 3d metal [2], as conversion reactions. The active material is created internally by an initial conversion reaction by which the compounds react with lithium to yield nanometallic particles. Reversible capacities as high as 1000 mAh/g have been realized with such conversion anodes. Co₃O₄ is a popular conversion anode material. In this work, we have used Co₃O₄ prepared with avian egg membrane as a template as a conversion anode material. Briefly, clean, dry outer membranes of avian eggs were impregnated with a methanolic solution of Co(NO₃)₂, dried and heat treated at 800^◦C for 5, 10, 15 and 20 h to yield Co₃O₄. The products were subjected to XRD, HRTEM and Raman spectroscopic studies. Lithium insertion behaviour was studied with 2032-type coin cells containing lithium anode and an electrolyte of 1M LiPF₆ in 1:1 (v/v) EC-DMC between 3.000 and 0.002 V.

Fig. 1 shows typical TEM and HRTEM images of Co₃O₄ synthesized by a 10-h heat treatment. Particles as small as 100 nm can be seen. Cycling studies (Fig. 2) show a first-cycle irreversible capacity of 400 mAh/g. The reversible capacity appears in two regions: a flat region around 1.5 V vs. Li⁺/Li, accounting for about 500 mAh/g followed by a sloping region that accounts for about 300 mAh/g. The hysteresis between the charge and discharge profiles is characteristic of conversion electrodes.

[1] P. Poizot, S. Laruelli, S. Grugeon, L. Dupont, J.M. Tarascon, Nature 407 (2000) 496.

[2] J.M. Tarascon, S. Grugeon, M. Morcrette, S. Laruelle, P. Rozier, P. Poizot, C.R. Chim. 8 (2005) 9.

C2-C3 Plant, Dahej: ONGC’s pioneering venture in extraction of VAP from LNG

Extraction of value added products from Liquified Natural Gas (LNG) has never been attempted before. The C2-C3 Extraction Plant at Dahej, Gujarat is the first LNG processing plant in the world. The value added products viz Ethane (C2), Propane (C3) and Butane (C4), is feedstock for the ensuing grass root petrochemical complex (OPaL). The extraction plant consists of one train of design capacity 5.0 MMTPA (625.0 ton/h) of rich LNG with a provision of one additional train. The rich LNG is sourced from Petronet LNG Ltd (PLL), a Joint Venture of ONGC and other oil companies is located adjacent to the C2-C3 Plant.

Toyo Engineering Corporation, Japan (TEC) has developed a cryogenic process for extracting Natural-gas liquids (NGLs; C2, C3, C4 and other hydrocarbons) from Liquefied Natural Gas (LNG), known as COREFLUX^®-LNG Process. COREFLUX^®-LNG process refluxes with a methane-rich (> 99%) stream, which is obtained from an overhead condenser that is cooled by the LNG feed. The remaining overhead vapors are compressed and liquefied in a second condenser, resulting in LNG. Ethane, Propane and Butane are recovered from the bottom of the Demethanizer. The design allows the column to operate at lower operating pressures which result in a reduced reboiler duty.

This plant also has some more unique features. Schoepentoeter™, a proprietary Shell vane type inlet device has been used for introducing the feed into the Demethanizer column. The purpose of a Schoepentoeter™ is to decrease the momentum of the feed and achieve an even gas distribution across the vessel cross section. For accurate flow measurements during custody transfer in transportation of LNG in pipeline, an eight path high performance a Caldon make ultrasonic meter has been installed. Custody transfer of LNG in pipeline mode is a novel concept.

Due to acute shortage of quality water in the vicinity, an air assisted flare (Zeeco UFO series) has been installed to dispose off waste gases. The advantages of this type of a flare are its capability of burning heavier hydrocarbons in a smokeless manner due to superior mixing as well as an extended service life with lower operating costs at a lower noise level.

This paper will endeavour to discuss process outline of C2-C3 plant along with some of the unique features highlighted.

Study of wetting characteristics of liquid na on different metal surfaces

Liquid Na is a highly effective heat transfer fluid in high temperature reactors like Nuclear reactor, internal combustion engines etc. A detail study of the interactions between different metal surfaces and liquid Na is very helpful for different purposes.

Taking the help of molecular simulation technique, wetting characteristics of liquid sodium on different metal surfaces (such as Ni, Cr and steel) are being studied. Equilibrium Molecular dynamics are being conducted to study the structure, dynamics and contact angle of liquid Na at different temperatures. Contact angles are measured by using different simulation methods and the comparison is shown. We present a comprehensive study of wetting transition of liquid Na using molecular simulation techniques.

Studies on scale formation and mitigation on continuously operating heat exchanger test rig

Formation of mineral scales poses significant problem in cooling water system. Deposition of undesirable inorganic salts and other impurities causes scaling. The potential for mineral scale formation continues to be by far the most costly design and operating problem in heat exchange equipments. Fouling and scaling on heat transfer surface reduces the efficiency of heat exchangers. The design of heat exchangers takes into account the decrease of heat transfer by increasing the heat transfer area. Due to scaling, the cross-section flow area reduces and the friction factor increases, which causes an increase in the pressure drop across the apparatus. In addition, the fouling layer has a low thermal conductivity, which increase the resistance to heat transfer and reduces effectiveness of heat exchangers significantly. Thus the operational and technical problems may eventually translate into substantial economic penalties. Continuously Operating heat exchanger test rig was subjected to water containing calcium sulphate salt. Heat transfer coefficient and pressure drop was measured with and without antiscaling agent addition. It was found that the heat transfer coefficient and pressure drop across the heat exchanger improves in presence of antiscaling agent.

Keywords: Scaling, Antiscaling agent, Heat Transfer Coefficient, Pressure drop

Rheological characterization of unsaturated polyester resin used in resin transfer molding

Liquid Composite Moulding process (LCM) such as Resin Transfer Moulding (RTM) generally produces polymer matrix composites by pressurizing precatalyzed resin into mould cavities that contains reinforcement fibers. Reinforcement performing, mould filling and curing are the steps involved in the LCM process. Complete filling of the mould with adequate wetting of the fibrous media is the primary objective in resin transfer moulding (RTM). Incomplete impregnation of the reinforcement preform results in expensive defective parts, which must be scrapped. Therefore, the simulation of the resin flow through the preform is an important step in modeling RTM manufacturing process. RTM involves a large number of variables related to process and product performance. Among them, rheology of the resin is the governing factor for the mould filling and the flow front progression, which directly influences the process efficiency. The resin viscosity during mould filling implicitly depends on the precatalyzed curing reaction and the process temperature. Hence, the evolution of the resin cure viscosity during mould filling can be correlated to the degree of cure and temperature. In this study, the rheological characterization of an medium reactive Unsaturated Polyester (UP) resin which is commonly used in RTM process has been quantified with varying proportions of accelerator and catalyst and temperature effects. The viscosity measurement has been performed using Bohlin Viscometer under constant shear rate conditions. The viscosity has been recorded as the function of elapsed cure time until the onset of resin gelation, where the resin loses its mobility. The extent of cure reaction data has been obtained for the unsaturated polyester resin from the literature and it has been correlated with the experimental measure rheological data.

Sugar refinery effluent characterization and pre-treatment-a case study

The physico-chemical characteristics and amenability to biological treatment of sugar refinery effluent was evaluated by taking samples of the influent and effluent from the pretreatment plant of a sugar refinery plant. Manual and systematic sampling was used to collect the effluent samples and the effluent discharge was measured using an Millitronics open channel meter. Samples were analysed using standard methods as outlined in the Standard Methods Handbook (APHA, AWWA, WEF). The effluent was characterised by high concentrations of organic matter and low levels of pH, suspended solids (SS) and total dissolved solids (TDS). Chemical oxygen demand (COD) levels ranged from 755-22,780mgl^-1 greatly exceeding the municipality regulatory limit of 2000mgl^-1 in most instances, while the level of SS was well below the regulatory limit of 600mgl^-1. The pH levels ranged from 5.1-8.4 and were below the lower regulatory control limit of 6.5 in most instances. The effluent was found to be readily biodegradable with a K_L value of 0.71day^-1 and therefore amenable to biological treatment process employed in the plant. However, the reduction in COD levels was initially less than 25% and after further refurbishments to the biological treatment plant a 50% reduction was achieved. The presence of biocides in the effluent from the cooling towers and lack of adequate bacterial slime in the trickling tower packing reduced the overall efficiency of the effluent treatment plant. The amount of effluent discharged per day ranged from 3-72m³ depending on production levels and approximately 10% of the total water used in the plant is discharged as effluent from the cooling towers and char house.

Key words: sugar refining, effluent characterization, biological treatment

Acceleration of Azo Dye Decolorization Using Redox Mediators and Complete Bio Degradation of the Aromatic AMINES in a sequential BIOREACTOR

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Estimation of Unbiased Values of Parameters in Selective Oxidation of N-Butane to Maleic Anhydride Using Bootstrapping technique

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