Renewable Energy Resources and Technologies
Sharareh Esmaeili; Kambiz Tahvildari; Barat Ghobadian; Masoud Dehghani-Soufi; Sanaz Mohammadzadeh Koumleh; Tirth Panchal
Abstract
The presence of increasing concerns and enforcement of growing regulations over environmental pollution are nowadays at play. The pollution arising from mineral oils is among the major concerns. With the gradual reducation of the world oil reserves, an increasing pressure comes into play for finding ...
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The presence of increasing concerns and enforcement of growing regulations over environmental pollution are nowadays at play. The pollution arising from mineral oils is among the major concerns. With the gradual reducation of the world oil reserves, an increasing pressure comes into play for finding sustainable alternatives. Being appealing alternatives, vegetable oils consist of different fatty acids; however, they cannot be applied directly to internal combustion engines owing to their poor oxidation stability and high pour point value. Biolubricants are considered to be a new generation of lubricants, which are renewable and biodegradable and are produced from the chemical modification of vegetable oils. There are few studies investigating the feasibility of using the mixture of fatty acids as biolubricant feedstock. In this study, epoxidation, oxirane ring opening with palmitic acid and p-Toluenesulfonic acid, esterification reaction with octanol, and reaction of the remaining hydroxyl group with stearic acid were applied to modify the mixture of oleic and linoleic fatty acids and produce biolubricant. For this purpose, the IR spectrums of each epoxide, monoester, diester, and triester products were obtained and analyzed. At the end of the experiments, monoester, diester, and triester were obtained with 94 % yield, with 96 % yield, and with 98 % yield, respectively. Eventually, the final product was found with physicochemical properties comparable with the physicochemical properties of the lubricant standard ISO VG10.
Renewable Energy Economics, Policies and Planning
Somayeh Dehhaghi; Shahla Choobchian; Barat Ghobadian; Homayon Farhadian
Abstract
The purpose of this study is to present a renewable energy policy model in the agricultural sector of Iran. To achieve this goal, a questionnaire consisting of 57 items was designed. The reliability of the questionnaire was confirmed by Cronbach's alpha (0.916). Also, to analyze the validity and reliability ...
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The purpose of this study is to present a renewable energy policy model in the agricultural sector of Iran. To achieve this goal, a questionnaire consisting of 57 items was designed. The reliability of the questionnaire was confirmed by Cronbach's alpha (0.916). Also, to analyze the validity and reliability of the research tool, the Average Variance Extracted (AVE) and Composite Reliability (CR) were calculated. The validity of the questionnaire was determined using face validity, Content Validity Ratio (CVR), and Content Validity Index (CVI). The statistical population of the study consists of energy policymaking experts who were estimated at about 80 people. The sampling method was random and 70 samples answered the questionnaire using the Krejcie and Morgan table. Using structural equation modeling and the maximum likelihood method and using LISREL software, the model fit was estimated at a favorable level. Based on the findings, it was found that the priorities of the agricultural sector and the needs of this sector had not been considered in renewable energy policymaking. Policymaking is done top-down and stakeholders are not considered. Renewable equipment market policies are not adequate and the market is not properly managed. Interaction between policymaking institutions is not in good shape. The results of this study can help address the various shortcomings of the renewable energy policy as well as reduce the common inconsistencies in this area. Finally, suggestions were made for the development and promotion of policies in the field of renewable energy in the agricultural sector of Iran.
Renewable Energy Resources and Technologies
Mehdi Zare; Barat Ghobadian; Seyed Reza Hassan-Beygi; Gholamhasan Najafi
Abstract
In CI engines, the evaporation rate of fuel on various hot surfaces, including the combustion chamber, has a significant effect on deposit formation and accumulation, the exhaust emissions of PM and NOx, and their efficiency. Therefore, the evaporation of liquid fuel droplets impinging on hot surfaces ...
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In CI engines, the evaporation rate of fuel on various hot surfaces, including the combustion chamber, has a significant effect on deposit formation and accumulation, the exhaust emissions of PM and NOx, and their efficiency. Therefore, the evaporation of liquid fuel droplets impinging on hot surfaces has become an important subject of interest to engine designers, manufacturers, and researchers. The aim of this study is to investigate the evaporation characteristics based on droplet lifetime and critical surface temperature (the maximum heat transfer rate) of diesel and biodiesel fuel droplets on hot surfaces. In order to determine the effects of diesel fuel, canola oil biodiesel, and castor oil biodiesel, the droplets impinging on the hot surfaces of aluminum alloy (7075) and steel alloy (1.5920) and the evaporation lifetime of diesel and biodiesel fuels were measured. Statistical analysis (ANOVA and Duncan’s multiple-range test) was carried out using SAS software. The results showed the maximum critical surface temperature of 450 °C for the castor oil biodiesel on steel 1.5920 surface and the minimum one for diesel fuel (350 °C). In this case, both surfaces had the same droplet lifetimes of approximately 2 s. The results of ANOVA showed the significant effect of the surface material and fuel type on the evaporation lifetime of fuel droplet at 1 % probability.
Environmental Impacts and Sustainability
Sepideh Abedia; Fatemeh Razi Astaraiea; Barat Ghobadian; Omid Tavakoli; Hassan Jalili
Abstract
Nowadays, the replacement of renewable energies such as biofuels is one of the main priorities in environmental programming and investments. This study is based on sustainable strategy towards integrating algal biomass generation as a green feedstock with wastewater treatment, CO2 bio-fixation, and bioenergy ...
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Nowadays, the replacement of renewable energies such as biofuels is one of the main priorities in environmental programming and investments. This study is based on sustainable strategy towards integrating algal biomass generation as a green feedstock with wastewater treatment, CO2 bio-fixation, and bioenergy production. Therefore, the performance of Trichormus variabilis in biomass production together with ammonium and phosphate removal from an actual effluent obtained from a mixed wastewater streams has been investigated using two mixing methods under aeration and agitation conditions. Dilutions of 10 %, 20 %, 40 %, 60 %, 90 % and 100 % (v/v) were used for growth evaluation. The results showed that the bubbled air effectively enhances the biomass productivity. However, the agitation system was suggested to cultivate the algae in the wastewater due to the elimination of possible mechanical stimulation stress on cells. Moreover, high pH levels (pH>8) indicated a negative inhibitory effect on growth. Thus, unexpected inhibitory impacts were removed through providing the wastewater dilutions mixed with BG11 culture medium, which contains essential required nutrients, to support the algal growth in the wastewater, adjust pH and remove the mechanical stress induced by bubbling compressed air. The results with respect to investigating the effect of the inoculums and wastewater concentrations on the biomass production suggested that the highest biomass generates with 30 mg.mL-1 inoculum in 40 % mixed wastewater diluted by the BG11 medium having the highest potential in CO2 bio-fixation of 9.19±0.64 g.L-1. The results of the wastewater analysis demonstrated the removal potential of ~43 % and ~75 % for NH4+ and PO43−, respectively. The generated biomass after phycoremediation and CO2 bio-fixation can be effectively utilized in different types of biofuel production.
Renewable Energy Resources and Technologies
Nemat Keramat Siavasha; Gholamhasan Najafi; Teymour Tavakoli; Barat Ghobadian; Esmail Mahmoodi
Abstract
Ducted wind turbines are a kind of small wind turbine having a diffuser or any other shape around the rotor which increases the air flow through the blades and absorbs more power. In the present study, a small wind turbine was ducted with a relatively simple ring and its performance was investigated ...
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Ducted wind turbines are a kind of small wind turbine having a diffuser or any other shape around the rotor which increases the air flow through the blades and absorbs more power. In the present study, a small wind turbine was ducted with a relatively simple ring and its performance was investigated in a wind tunnel. The duct is shaped using rolling steel sheets on a sloping surface and finally fabricated in double-glazed surfaces. The turbine utilizes polyester resin glass fiber-armed composite hollow blades. Bare turbine produces 165 watts in its highest power generation mode which can reach 282 watts when it is ducted. The evaluation of the system in the wind tunnel showed that the power generation of the ducted system compared to a conventional turbine was 14 % higher on average. Furthermore, the rotor speed of the ducted turbine was 45 % higher than the bare one which increases the tip speed ratio (TSR). In this study, TSR increment raised the absorbed power in the developed wind turbine.
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 ...
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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.
