Research Article
Mohammad Kord; Seyed Mojtaba Sadrameli; Barat Ghobadian
Abstract
The purpose of this research work was to investigate the optimum operating conditions for biodiesel production from castor oil using a microwave. The Box–Behnken design of experiment was carried out using the Design Expert 7. A response surface methodology (RSM) was used to analyze the influence ...
Read More
The purpose of this research work was to investigate the optimum operating conditions for biodiesel production from castor oil using a microwave. The Box–Behnken design of experiment was carried out using the Design Expert 7. A response surface methodology (RSM) was used to analyze the influence of the process variables (molar ratio of methanol to castor oil, catalyst concentration, reaction time, and microwave power) on the biodiesel yield. Optimizing biodiesel production reaction based on the yield of reaction by means of response surface method showed that 1.44 wt.% of catalyst concentration, 7.12:1 molar ratio of alcohol to oil, microwave power of 500 W and 120 seconds of reaction time produces the best results for maximizing the conversion percent. Finally, Biodiesel samples were analyzed with Gas Chromatography (GC) method for determination of fatty acid methyl ester yield. The yield of reaction obtained was 92.15% with above operating conditions and temperature of output flow was 58 oC.
Research Article
Somayeh Choobin; Bahram Hosseinzadeh Samani; Zahra Esmaeili
Abstract
In recent years, increasing the awareness on the environmental problems, especially global warming, has increase the concerns about the impact of emissions on the global climate. The current study was conducted to evaluate and analyze the environmental effects of rapeseed production in the form of life ...
Read More
In recent years, increasing the awareness on the environmental problems, especially global warming, has increase the concerns about the impact of emissions on the global climate. The current study was conducted to evaluate and analyze the environmental effects of rapeseed production in the form of life cycle using SimaPro software with the aim concentration on climate changes and impact of acidification. In order to perform the experiments, 1 tone rapeseed was used as operational unit. The required data was collected from 30 farms in Izeh city. Ten environmental indexes including depletion of groundwater resources, potential to acidification, potential to eutrophication, potential to global warming, ozone depletion potential, human toxicity potential, potential to toxicity of fresh water and marine fish, potential to environmental toxicity, potential to photochemical oxidation were investigated in this research. Results showed that the amount of greenhouse emissions for rapeseed was equal to 112.73 kg of carbon dioxide equivalent. It was also revealed that chemical fertilizer had the highest share among the evaluated inputs within the life cycle. Results obtained in this survey indicated that management of nutrients and pesticides can be considered as a concentration point for optimizing the environmental influences of rapeseed production in the related region.
Research Article
John G Mbaka; Mercy. W. Mwaniki
Abstract
Small Hydro-power Plants (SHP) are an important source of electricity in many countries. However, little is known about SHP in Kenya. This paper reviews the status, challenges in implementation of SHP and prospects for future development of SHP in Kenya. The paper shows that SHP has not yet fully utilized ...
Read More
Small Hydro-power Plants (SHP) are an important source of electricity in many countries. However, little is known about SHP in Kenya. This paper reviews the status, challenges in implementation of SHP and prospects for future development of SHP in Kenya. The paper shows that SHP has not yet fully utilized the available hydro-power potential. The challenges associated with SHP development should be addressed to realize its full hydro-power generation potential in the future.
Research Article
Olatunde A. Oyelaran; Yau Y. Tudunwada; James K. Abidoye; Olawale M. Sanusi
Abstract
Biogas production from co-digestion of local brewery waste (BW) and cow dung (CD) was study for value added to this solid waste. The objective of this research was to fine the optimum condition for maximum biogas production and also examined the effectiveness of the biogas residue (liquor from anaerobic ...
Read More
Biogas production from co-digestion of local brewery waste (BW) and cow dung (CD) was study for value added to this solid waste. The objective of this research was to fine the optimum condition for maximum biogas production and also examined the effectiveness of the biogas residue (liquor from anaerobic digestion process) as a nitrogen source for the production of okro. The experiments were performed in a laboratory scale of 1.5 liters plastic bottles were used as digesters operated in batch mode and mesophilic conditions [35°C±0.5]. The feedstock were test in the following ratios CD:BW, 90:10, 80:20. 70:30, 60:40, 50:50, 40:60, 30:70. 20:80 and 10:90. The maximum biogas yield was attained with mixtures in the proportions of 70:30 CD:BW. At these proportions, there was a biogas yield increase as compared to other ratios. The addition of BW increased the biogas yield from 0.40t/lt.day to 0.92lt/lt.day. It was found that CD: BW of 70:30 is the optimum ratio from batch process. The gradual reduction of the VFA concentration clearly indicated the stability of the process. A micro (pot) experiment was conducted to study the comparative effects of biogas residues, and NPK fertilizers on growth and yield using okro as the test crop. Twelve experimental soil filled pot in a complete randomized block design was used comprising of three each for Control T1 (no NPK and no BR), T2 100% NPK fertilizer, T3 50% BR plus 50% NPK fertilizers and T4 biogas residues (BR 100). The parameters studied showed that plant height, root length, number of fruits per plant and fruit weight was affected by the addition of biogas residue. A maximum 20.2% plant height increase over control T1 was observed in T3, 100% NPK has 10% while T4 has 8%. A maximum increase of 28.57% number of fruits was recorded in treatment T2 and T3, while 14.29% increased was recorded in T4 compared with control. The 50% BR applied in combination with 50% NPK (T3) resulted in 25.42% increase in fruit weight over control, T4 has 20.34% and 16.95% was observed in T2. Based on these results, it may be concluded that the application of approximately 50% of biogas residue and 50% inorganic fertilizer improves the production of okro.
Research Article
Joseph Pemndje; Adrian Ilinca; Théophile Rufin Tene Fongang; Rene Tchinda
Abstract
This paper determines and compares the cost of energy (COE) of various hybrid systems for several off-grid facilities in North and Far North regions of Cameroon by integrating renewable sources and/or storage with diesel generators. The estimated annual energy production by solar PV systems and wind ...
Read More
This paper determines and compares the cost of energy (COE) of various hybrid systems for several off-grid facilities in North and Far North regions of Cameroon by integrating renewable sources and/or storage with diesel generators. The estimated annual energy production by solar PV systems and wind turbines is also discussed. The aim is to study the application of a high penetration renewable energy system to be used as backup in case of failure of the electrical network. Based on meteorological data provided by NASA, a hybrid system using photovoltaic panels, wind turbine, diesel generator, batteries and converter was designed using HOMER software to supply electricity to these loads. It is shown that the use of renewable energies (wind and photovoltaic), despite the fact that it requires large investments initially, is the most economical, most profitable and least polluting system.
Research Article
Hossein Ghadamian; Hassan Ali Ozgoli; Mojtaba Baghban Yousefkhani; Foad Farhani
Abstract
Regenerative Fuel Cell (RFC) systems are used for the enhancement of sustainable energy aspect in conventional fuel cells. In this study, a photovoltaic-electrolyzer-fuel cell integrated cycle has been presented. The proposed system has been designed as a novel approach for alleviating the ...
Read More
Regenerative Fuel Cell (RFC) systems are used for the enhancement of sustainable energy aspect in conventional fuel cells. In this study, a photovoltaic-electrolyzer-fuel cell integrated cycle has been presented. The proposed system has been designed as a novel approach for alleviating the restrictions on energy streams in the RFC systems. Modeling of the system has been performed from the mass and energy point of view, based on both theoretical and practical procedures. To generate electricity from hydrogen, a proton exchange membrane fuel cell, integrated with an electrolyzer system which works by solar energy, has been used. Optimized results of required photovoltaic area have shown significantdifferences between theoretical and practical approaches. Moreover, all efficiencies of two scenarios including total efficiency have been indicated and analyzed. The main advantage of this system in comparison with single solar systems, is generation of internal energy of about 2.3 kW for producing 1 kW electricity by the fuel cell.
Research Article
Mohammad Zarei-Jelyani; Mohsen Babaiee; Abdolmajid Ghasemi; Rahim Eqra
Abstract
Traditional vanadium batteries use pure sulfuric acid as electrolyte, but H2SO4 does not absorb enough vanadium ions to make the electrolyte an efficient energy source. This study investigates the effect of hydroxylation process on electrochemical and operational properties of carbon felt electrode in ...
Read More
Traditional vanadium batteries use pure sulfuric acid as electrolyte, but H2SO4 does not absorb enough vanadium ions to make the electrolyte an efficient energy source. This study investigates the effect of hydroxylation process on electrochemical and operational properties of carbon felt electrode in VOSO4 solution with an optimized supporting electrolyte (a mixture of six parts HCl and 2.5 parts H2SO4). Carbon felt electrode was hydroxylated with mixed acids of H2SO4 and HNO3 in a stainless steel autoclave for 6 h. Then thermal treatment of electrode was performed at 400 oC for 5h. Obtained results of cyclic voltammograms showed that when the carbon felt was hydroxylated, both oxidation and reduction peak currents were increased remarkably and the peak potential separation is decreased from 356 mV to 246 mV, suggesting that the electrochemical activity and the kinetic reversibility on HCF electrode were improved compared to the pristine one. According to results of electrochemical impedance spectra, charge transfer resistance (Rct) was calculated to be 648 Ω for pristine carbon felt. The obtained Rct at hydroxylated electrode (176 Ω) shows a decrease of about 73 % in Rct. Charge-discharge profiles of two cells assembled with the pristine carbon felt (cell A), and hydroxylated carbon felt (cell B) showed that energy, voltage and coulombic efficiencies were significantly improved by using the hydroxylated electrodes inside the cell of vanadium redox flow battery.