Sharif Digital Repository

Biodiesel as an alternative fuel for fossil diesel has many benefits such as reducing regulated air pollutants emissions, reducing greenhouse gases emissions, being renewable, biodegradable and non-toxic. In this study, used frying oil was used as a low cost feedstock for biodiesel production by alkali-catalyzed transesterification. The used frying oil was originally a mixture of various oils obtained from vegetables that are native to Iran. The design of experiments was performed using a 5-level-5-factor central composite design coupled with response surface methodology in order to study the effect of factors on the yield of biodiesel and optimizing the reaction conditions. The factors... 

The enzymatic transesterification of castor oil with methanol in a solvent free media is carried out using lipase catalyst. The influence of several operation conditions on the production of biodiesel was analyzed i.e. the amount of enzyme, molar ratio of methanol to castor oil, reaction temperature and reaction time. It is observed that with increase in molar ratio, reaction time and enzyme amount, the amount of product (biodiesel) increased. When reaction temperature increased, the amount of biodiesel increased firstly and then decreased. The optimum conditions for the reaction were as follows: enzyme amount 300 mg, molar ratio of methanol to oil 9:1 and temperature 55°C. The maximum... 

In this work the transesterification reaction of waste cooking oil in the present of solid catalyst as a type of solid-liquid catalytic reaction, has been studied. For this purpose, two types of alkali solid catalysts were synthesized. CaO-ZrO2 and KOH/γ-Al2O3 catalysts were prepared by co-precipitation and impregnation method, respectively. These catalysts were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), X-ray fluorescence (XRF), BET surface area, and temperature programmed desorption of CO2 (TPD-CO2). The obtained results for the CaO-ZrO2 catalysts indicate that with increasing Ca/Zr atomic ratio, the activity of catalysts increases, but the stability... 

Biodiesel as an alternative fuel for fossil diesel has many benefits such as reducing regulated air pollutants emissions, reducing greenhouse gases emissions, being renewable, biodegradable and non-toxic. In this study, used frying oil was used as a low cost feedstock for biodiesel production by sodium silicate as an alkaline catalyst in transesterification reaction in order to optimize the conditions of biodiesel production. The factors studied were: reaction temperature, molar ratio of methanol to oil, catalyst amount and catalyst recovering. The optimum conditions of reaction obtained as follows: methanol to oil molar ratio of 7:1(mol⁄mol), catalyst amount of 3% w/w and reaction... 

Superparamagnetic core/shell nonporous (S1) and core/shell/shell mesoporous (S2 and S3) nanocomposite magnetite/silica particles with a magnetite cluster core of 130±30 nm, a nonporous silica shell of 90±10 nm thickness, and a mesoporous silica shell of 70±15 nm thickness were prepared thorough a simple method. Mesoporous particles were prepared with two BJH pore sizes (2.44 for S2 and 3.76 nm for S3 particles, respectively). The fabricated S1, S2 and S3 particles present high saturation magnetization values of 20, 13 and 17 emu/g, respectively. As a biological application, the lipase from Pseudomonas cepacia was successfully immobilized onto the amino-functionalized nanocomposite particles... 

In a single chemical plant, the operation of each unit operation is not independent of each other. In the other hand, the main operations are performed in reactors following by several separation steps including distillation and purification units. The total energy requirements are sullied by the heat exchanger networks. The performance of these systems is improved by integration and intensification of the reactor and distillation column in a single unit. The main objective of the present work is to provide an effective design approach to intensify the reactor and distillation column. In a reactive distillation column, the reaction and separation is done in a single unit. Increasing... 

Biodiesel can be a good alternative for fossil diesel since it isrenewable, biodegradable and non-toxic. Also, in comparison with fossil fuels, it emits less air pollutants and greenhouse gases.Findacost effective and environmentally friendly wayforcontinuousproductionofbiodieselcanaddressmany of our environmental concerns. In this study, we applied heterogeneous alkali-catalyzed transesterification as method and used waste frying oil as a low cost feedstock for biodiesel production. The project was performed in two phases. First, experiments were conducted in astirred reactor to finda suitable catalyst which was strontium carbonate calcinated for 3:24 hours in 975̊C.
RPB(rotating... 

The experimental investigation of biodiesel production stages from microalgae especially lipid extraction stage was conducted in this thesis. The optimal rate of biomass productivity and optimal method in lipid extraction for biodiesel production was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out. Then, several methods of lipid extraction using different solvents such as chloroform, methanol, and n-hexane were investigated and the best... 

Nowadays, due to depletion of fossil fuels and the emission of green house gases, biodiesel has attracted lots of attention as a renewable, non-toxic, and biodegradable fuel. Biodiesel can be produced from different resources such as vegetable oil, animal fat and algae oil. In this study, waste frying oil was used as a raw material that can reduce the probable hazardous effects of its disposal and produce a clean fuel at the same. Biofuel was produced through an enzymatic method using the whole cell of Rizopu oryzae (a filamentous fungus) in both immobilized and free forms. In order to find the optimum conditions for biodiesel production, four variables including temperature, methanol to oil... 

Increasing emissions of greenhouse gases from one hand and decline in the fossile resources of energy on the other hand has raised the motivation of searching for renewable sources. Biodiesel, because of having perfect feature for replacing with petroleum diesel, has been considered as candidate for this purpose. Using enzymatic reaction is one of the methods for biodiesel production. Understanding the kinetics of this reaction is important to achieve higher production rates.
In present work, the kinetic of transesterification of castor oil with use of Novozyme 435 (as enzyme) was investigated. Enzymatic biodiesel production is a bi-substrate (oil and alcohol) reaction. Genetic algorithm... 

Reduction in the oil reserves level and the increasing of fossil fuel prices and GHG has led to growing value of attention to biodiesel. Reserves of fossil fuels are running out and should have proper alternative for them. Environmental benign and renewable properties of biodiesel make it consider suitable candidate to replace fossil fuels.
In this study, continuous production of biodiesel and optimization of important and influential parameters have been investigated. The method is concluded of trans esterification of soya oil with methanol as feed in presence of homogeneous catalyst of NaOH. The reactor was simple with high efficiency and low operational and investment cost. The... 

The current study deals with application of a surfactant-like Brønsted acidic ionic liquid (IL) 1-dodecyl-3-methylimidazolium hydrogensulfate (catalys 1) for Mannich reaction at room temperature. The reaction has been efficiently proceeds in water as solvent without using any harmful and expensive organic additives. Our observation has been shown that the reaction is selective for cyclohexanone and no product was observed by using cyclopentanone at room temperature. Density functional theory (DFT) calculations were performed to provide evidence about the nature of reactivity of the cyclohexanone/cyclopentanone. The activity of the catalyst 2 (1-dodecyl-2,3-dimethylimidazolium... 

In the current work, jatropha oil was studied in the hetrogenious solid catalytic transesterfication reaction. For this perpous, KOH/CNT catalyst which was prepared by dry impregnation method was used. SEM, XRD and TGA were applied for the catalyst characterization. The results showed that for the KOH/CNT catalyst, by increasing the loading of KOH, the activity of the catalyst increased and the most active catalyst was prepared by 20% loading of KOH. The optimum conditions for transesterfication reaction in the percense of this catalyst were: 4.7% catalyst weigth and the 24.5 molar ratio of methanol to oil and also the reaction time of 2 houres which the rate of reaction at this time is... 

The current thesis deals with designing of functionalized nanoporous catalysts modified with organic groups and ionic liquids and their applications for some challenging organic reactions such as synthesis of adipic acid and fatty acid esterifications. In this condition the catalysts show enhanced activity since the hydrophobicity of the surface can tune by applying organic groups. In this regard, oxidation of cyclohexene was performed using hydrogen peroxide as oxidant in the present of tungstate based task–specific ionic liquids and silica–functionalized ammonium tungstate as green catalysts. The results indicate that adipic acid achieves in high yield with excellent selectivity.... 

The experimental investigation of biodiesel production stages from microalgae especially biomass production stage was conducted in this thesis. The optimal rate of biomass productivity was determined.
A photobioreactor was designed and constructed to cultivate microalgae C. Vulgaris according to researchers’ works and obtained results in this study. The process parameters were examined and the optimal parameters were obtained according to the necessary tests which were carried out.
According to the results, the optimal condition for growing of microalgae was obtained with aeration of 6 lit/min with 3% CO2, and CO2 injection regime of 45 sec. injection and 3 min. of stoppage. A rapid... 

Biodiesel has drawn the attention of many researches to itself as a replacing source for crude oil, recently. Transesterification is one of the most popular methods used for biodiesel production. Enzyme transesterification is a more simple method in comparison with acidic or basic transesterification. However, the high price and low yield of enzyme transesterification has caused many obstacles in its application. Enzyme engineering has gained much attention as a way to improve enzyme performance. In this thesis, biodiesel production by a native enzyme named Bacillus thermocatenulatus, and two engineered-enzymes is studied. First, effective parameters and variables in biodiesel production by... 

In this research, experimental study and modeling of biodiesel production process from microalgae has been investigated. First, to have a biomass with suitable lipid content, a novel two-step process based on cultivation under nutrient sufficient followed by cultivation under nitrogen starvation condition has been proposed. Then the effect of using different organic and inorganic carbon sources on this process has been investigated which the results indicated that sodium acetate had a better performance compare to other carbon sources. In the following, the effect of using different light regimes on growth rate, lipid content and fatty acid composition have been investigated. Experimental... 

Nowadays, one of the most basic human problem is how to manage energy resources for sustainable development and how to deal with problems caused by growing energy consumption. Various scenarios are being discussd that the most important of them can be considered research on finding alternative energy sources that are renewable and do not have common pollution. Thus, according to researches carried out until now, using sources such as wind, water, solar biomass, etc. have been proposed. However, due to problems in the development of each of these sources, biomass as the primary option has been introduced. because biomass has several subsidiaries, research shows microalgaes (as a subset) are... 

Clean and Renewable energies are one of the most important part of global policy. In order to reduce greenhouse gas emissions mostly from fossil fuels, many countries have introduced biofuels to avoid depletion of fossil fuels and decrease the pollution. In Iran, large dependency on crude oil and natural gas resources cause barriers for utilization of biofuels. The country has plenty of biomass resources that may guide national decision makers toward biofuels.In this study, biomass supply chain to produce biofuel is studied to reach sustainability. The model enables us to depict the optimal path to reach the economic, environmental, and social sustainability through the whole supply chain....