• Energy Research

The objective of this paper is to evolve simple and effective methods for the economic load dispatch (ELD) problem with security constraints in thermal units, which are capable of obtaining economic scheduling for utility system. In the proposed improved particle swarm optimization (IPSO) method, a new velocity strategy equation is formulated suitable for a large scale system and the features of constriction factor approach (CFA) are also incorporated into the proposed approach. The CFA generates higher quality solutions than the conventional PSO approach. The proposed approach takes security constraints such as line flow constraints and bus voltage limits into account. In this paper, two different systems IEEE-14 bus and 66-bus Indian utility system have been considered for investigations and the results clearly show that the proposed IPSO method is very competent in solving ELD problem in comparison with other existing methods.

In the present study, Kluyveromyces marxianus was utilized to study the batch fermentation kinetics of biomass production, substrate utilization and bioethanol production from woody stem Prosopis juliflora. The pre-treated substrate was subjected to Simultaneous Saccharification and Fermentation (SSF) under optimised conditions of pH (4.9), temperature (41 °C), substrate concentration 5% (w/v), inoculum concentration 3% (v/v) and the maximum concentration of bioethanol was found to be 21.45 g/l. The experimental data thus obtained from cell growth, substrate utilization and product formation are employed in the determination of kinetic parameters. Biological models such as Logistic model, Hinshelwood model were used for microbial growth and substrate utilization kinetics respectively. In case of product kinetics, Leudking-Piret plot, Gompertz model and Modified Gompertz model were utilised. Based on these models, kinetic parameters like maximum specific growth rate (µm), saturation constant (Ks), growth associated (α), non-growth associated (β) and yield coefficients (YX/S, YP/S) were estimated.

The depletion of fossil fuels has caused the price of petroleum to rise remarkably and created need for alternative energy such as biodiesel. In the present study, the biodiesel was produced from castor oil using ferromagnetic zinc oxide nanocomposite as heterogeneous catalyst for transesterification reaction. Single phase of nanocatalyst were confirmed by X-Ray Diffraction analysis. The spherical shape of the aggregated nanocatalyst was observed in Scanning Electron Microscopy. Magnetic properties were analysed using vibrating sample magnetometer. Atomic Force Microscopic analysis revealed the larger surface area and roughness of nanocatalyst. The biodiesel yield of 91% (w/w) was obtained in 50 min at 55 °C with 14 wt % catalyst loading and 12:1 methanol/oil ratio and was confirmed by Gas chromatograph with Mass Spectrometer. The result showed that the iron (II) doped ZnO nanocatalyst is a promising catalyst for the production of biodiesel via heterogeneous catalytic transesterification under milder reaction conditions.

Abstract The rapid industrialization and increase in the population has led to great energy demand in recent days. Various alternative sources of energy have been explored by researchers. Biodiesel is reported as best alternative renewable bioenergy. In the present work, mahua seed is a non-edible source used for extraction of biooil. The extracted biooil can be utilized for biodiesel production. The main objective was to study the effect of various extraction conditions and kinetics of extraction of biooil from mahua seeds. The suitable solvent ratios for extraction were compared among diethyl ether:ethanol, chloroform:methanol, chloroform:ethanol, iso-propanol:methanol in the proportions 3:1, 2:2 and 1:3 respectively. Experimental runs provided high biooil yield at temperature 50 °C and contact time 20 min. The extraction process was observed under the influence of an ultrasonic bath. The maximum biooil yield of 82% was obtained under the optimum conditions of temperature 50 °C, Contact time 20 min, seed to solvent ratio (diethyl ether:ethanol) 1:10(3:1) under ultrasonication. The properties such as density, viscosity, calorific value, cloud point, flash and fire point of biooil obtained has met the standard values.

In this paper, an attempt has been made to find out the effect of blue metal stone on heat transfer coefficient for a passive single-slope distillation system in summer climatic conditions. The experiments have been conducted on a south facing, single slope, solar still of 10° inclination of condensing cover, in summer climatic conditions for 24 h on 5 different days for three different sizes of blue metal stone from 6 to 20 mm and this is finally compared by using the basin without any absorbing material. The thermal efficiency is calculated by using the energy balance equation.

The objective of this paper is to evolve simple and effective methods for the optimal dispatch problem in thermal units, which are capable of obtaining optimal power generations for a large-scale system. In an improved λ-based genetic algorithm (GA), the encoding parameter is normalized system incremental cost λnm. This approach takes network losses, ramp rate limits, and prohibited zone(s) into account because of GA’s flexibility. The features of a refined genetic algorithm are also incorporated in the λ-based GA approach. The probability of mutation and crossover is exponentially varied in each generation. Probability of limits has been fixed for mutation and crossover. The results of the λ-based GA and improved λ-based GA are compared. The latter is simple and effective. In the proposed improved λ-based GA, an optimal solution is obtained neglecting losses in the first stage. The resulting solution is given to load flow, and the network transmission loss is computed from load flow in the next stage. Th...

The present study was mainly focused on the production of biodiesel from Calophyllum inophyllum oil. The oil was characterized by GC-MS and stored for biodiesel production. The heterogeneous catalyst was synthesized for effective production of biodiesel. The synthesized catalyst was found to have good activity and stability. The surface and element characterization of zinc doped calcium oxide was characterized by SEM and EDAX. The size of nanocomposite was found to be in the range of 14.3-65.6 nm. The EDAX has confirmed the presence of zinc on the surface of the calcium oxide. The maximum biodiesel yield of 89.0% (v/v) was obtained at 55 °C in 80 min and catalyst concentration of 6% (w/v). The optimized methanol:oil molar ratio was obtained at 9:1 for the production of biodiesel. The produced methyl ester was confirmed by GC-MS analysis.

In the present work, the residual biomass of the green seaweed Ulva lactuca was chosen as feedstock to undergo separate hydrolysis and fermentation process to produce bioethanol. The hydrolysis process was optimized for cellulase, biomass, temperature, and time conditions. The maximum yield of fermentable sugars was 13.48 mg/mL. The recovered hydrolysate was subjected to fermentation using Saccharomyces cerevisiae. The bioethanol produced was subjected to gas chromatography coupled mass spectrometry analysis to determine the presence of ethanol. The technical performance and economic feasibility of the bioethanol production from U. lactuca were evaluated using the lab-scale data obtained for optimized conditions. The plant capacity was 10 MT/day of bioethanol production. The plant's capital investment and annual operating cost were 3.18 M$ and 0.86 M$ respectively. The total annual revenue of the plant was 1.41 M$. The minimum selling price of bioethanol was 0.47 $/kg. The ROI, payback period, IRR and NPV of the plant were 16.99 %, 5.89 years, 11.57 % and 291,000 $ respectively. The utilization of residual biomass for biofuels helps to develop an economic and environmentally sustainable plant.

In the present work, Ulva lactuca, a marine macroalgae was used for the production of biodiesel. The ultrasound assisted extraction of oil from autoclaved algal biomass was found effective with maximum yield. The maximum oil was extracted at optimal conditions of 5% moisture content of algal biomass, 0.15 mm size of biomass, 6:1 solvent: solid ratio, at 55 °C in 140 min. The n-hexane with co-solvent methyl tertbutyl ether has shown higher oil when compared to other co-solvents. The extracted oil was transesterified into biodiesel using silica doped with zinc oxide as novel heterogeneous nanocatalyst. The maximum biodiesel yield of 97.43% was obtained at optimized conditions of 800 °C calcination temperature, 8% catalyst concentration, 9:1 methanol to oil ratio, 55 °C reaction temperature and 50 min reaction time. The kinetics of the transesterification reaction was also studied. The Ulva lactuca was found as a potential source for biodiesel production.