Bikash Mohanty’s research while affiliated with Indian Institute of Technology Roorkee and other places

The present work shows that watermelon seeds have great potential to producing high linoleic and oleic acid content vegetable oil, which have beneficial effects on human health. In concern with developing new green processes for high-quality yield, the extraction is carried out with supercritical CO2 and compared with conventional extraction technique. Extraction has been conducted within the temperature and pressure range of 60–100ºC and 200–400 bar, respectively. To describe the kinetics, the extended Lack model has been selected and effectively applied to the description of extraction curves. The fitting parameter Z, W, and xk have been optimized by Box optimization technique.

Moringa oleifera seed is an important source of high oleic acid in vegetable oil. In the present work, supercritical extraction of moringa seed oil has been carried out to study the influence of operating temperature, pressure, particle size, carbon dioxide flow rate and co-solvent addition by performing experiments in the range of 333-373 K, 20-40 MPa, 0.50-1.00 mm, 0.83 × 10⁻⁴-2.50 × 10⁻⁴ kg/s, and 0-10% ethanol. The extraction data have been successfully modeled by extended Lack's model and fitting parameters are optimized by Box global optimization technique. The results showed that pressure has a significant effect followed by temperature, co-solvent, solvent flow rate and particle size.

The present Computational Fluid Dynamics (CFD) work deals with the modeling of complete coal direct chemical looping sub-pilot unit which use coal as fuel and ferric oxide supported on alumina as an oxygen carrier. The 2D CFD model of the complete arrangement incorporating both fuel and air reactors and their interconnecting parts was solved using FLUENT. The CFD model was run with two different sets of reactions-the first set with eleven and second set with eighteen reactions. Computed results for second set of reactions were found to be in good agreement with the published pilot plant data. The CFD model with second set of reactions predicted fuel conversion for Sub-Bituminous Coal (SBC) and Metallurgical Coke (MC) were 95.39% and 87.07% respectively while, the published results were 97-99% and 70-99% respectively. Further, the purity of CO2 in fuel reactor exhaust were 92.34% and 90.19%, while, the published were 99.8% and 99.6% for SBC & MC respectively. INTRODUCTION The exponential rising trend in energy consumption compounded with deteriorating quality of fossil fuel have forced scientists to seeks for alternate solutions to deal with the problems related to energy crises and greenhouse gases emission. Additionally, the clean and renewable sources of energy like the solar, the wind, and the geothermal energy are unlikely to meet the currently mounting energy demand in foreseeable future due to the constraints associated with such renewable energy. Furthermore, the constraint on nuclear power of its spent fuel management and susceptibility to catastrophic hazards makes it implausible to play a vital role

Low ash content coal as a fuel for chemical looping combustion for the production of clean energy along with CO2 capture has been well established. However, major coal deposits in the region of Asia-Pacific and Australia are of high ash content and thus, pose difficulties in utilization of this technology. Therefore, an attempt has been made in the present work to study chemical looping combustion of high ash coal. For this purpose a CFD model which incorporates both fuel and air reactors and their inter-connecting parts to simulate a real chemical looping pilot plant has been developed. The results obtained for sub-bituminous coal as well as metallurgical coke for the above reactor have been validated against the published data within an error band of +/- 7%-14%. The validated model is then used for two high ash content coals designated as A and B. Simulated results show that for A and B, fuel conversions are 93.8% and 87.79% respectively and purity of CO2 in fuel reactor exhaust are 89.12% and 90.73%. It has also been observed that, components of ash such as CaO, Fe2O3 show significant reactivity at the operating conditions, whereas, SiO2 exhibits almost negligible reactivity. Further, in case of high ash coal, due to its low carbon content, the fuel requirement increases to sustain operating conditions.

Radiation plays a dominant role in combustion space heat transfer. It is composed of three components, namely gaseous species radiation, soot radiation and crown surface radiation. The basis for model validation and the subsequent study of furnace operation is the spatial variation of radiant heat flux. Hayes and colleagues carried out measurements of crown incident radiant heat flux along the furnace axial centerline and developed a numerical model. However, the effect of soot was not quantified. In the present work, a numerical model is developed which considers the effect of soot radiation and is simulated using Fluent. The proposed model fits the experimental data of Hayes and colleagues within an error band of -6% to +14%.

The present work is related to development of a MINLP (Mixed integer non linear programming) model for the synthesis of HEN (heat exchanger network) considering pressure drop through connecting pipelines, heat exchangers and the layout of the equipment exchanging heat simultaneously. The pressure drop of shell and tube sides in a heat exchanger is considered in the model. Further, detailed plant layout is considered for accounting pressure drop in pipe line as well as piping cost. The objective function of the MINLP model is the TAC (total annual cost), which considers utility cost, capital investment cost of exchangers, pipe investment cost and pumping cost due to pressure drops in exchanger as well as in pipe length. The developed model is illustrated using a case study. The results show that the TAC of HEN is reduced by 27.4% than that obtained for the topology without considering pressure drop in exchanger. However, placement of exchangers in the layout contributes to 4.5% in TAC. Results found through the present model are compared with that of published models.

Fouling in Multiple Effect Evaporator (MEE) systems is the major unresolved problem encountered in most of the chemical process industries. In order to mitigate fouling from MEE system used in cane sugar industry, it is necessary to understand the type and nature of foulant present in it. In the current paper, authors have tried to present the detailed analysis of deposits present in each effect of a quadruple effect MEE system used in Indian sugar industry. For this purpose, various instrumental analyses were performed and different organic and inorganic compounds and elements present in the deposits were identified. Further, it has also been observed that some elements show a particular trend of deposition from first effect to last effect. This analysis will help industry to select particular mitigation technique to clean deposits.

Techno-economic development of chemical looping combustion (CLC) process has been one of the most pursued research areas of the present decade due to its ability to reduce carbon foot print during utilization of coal to generate energy. Based on a 2D computational fluid dynamics model, the present work, provides a computational approach to study the effect of operating pressure –a key parameters in designing of CLC reactors, on optimum operating conditions. The effects of operating pressure have been examined in terms of reactors temperature, percentage of fuel conversion and purity of carbon dioxide in fuel reactor exhaust. The simulated results showed qualitative agreement with the trends obtained by other investigators during experimental studies.