Sharif Digital Repository

In this study the kinetic modeling of visbreaking reactions of heavy oils was investigated using available experimental data from the literatures. The continuous lumping model was developed for kinetic analysis of visbreaking reactions. The normalized boiling point was used to describe the reactant mixture as a continuous mixture and the concentration distribution of the mixture would change under reaction conditions. The continuous model with five adjustable parameters was used to describe visbreaking reactions and these parameters were optimized for each feed and reaction temperatures in the range of 400 to 430ºC using the available experimental data. Therefore for a special feed in a... 

An industrial scale reactor for light olefinsproduction was modelledusing the oxidative dehydrogenation (ODH) of light paraffinsin a multi-tubular reactor system involving 10000 small diameter tubes immersed in a shell with proper liquid-cooled flows. Here a theory-based pseudo-homogeneous 1-D model describing the operation of a fixed bed reactor for the ODHparaffinstoolefins over a Ni-Nb-O mixed oxide catalyst (for ethane) and over a V2O5/γ-Al2O3catalyst (for Propane),was employed. The paraffin and oxygen conversions, gas process and coolant temperatures, as well as other parameters affecting the reactor performance, including pressure, were examined. Furthermore, the applied model showed... 

Volatile Organic Compounds (VOCs) have become an important source of air pollution due to their extended use as solvents in many industrial processes. Aliphatic and aromatic VOC removal from contaminated air can be achieved by a variety of methods including catalytic oxidation, adsorption, and biological treatment. Catalytic oxidation is often the preferred process due to its low cost and high efficiency. Supported transition metal catalysts are effective and inexpensive catalysts for VOC removal from contaminated air. The objective of this project was to prepare low cost transition metal catalysts (Fe, Ni, Co, and Cu) supported on alumina for catalytic oxidation of cyclohexane (as a... 

Exhaust gases from poultry rendering facilities contain volatile organic compounds (VOCs) that are a nuisance, odorous, and smog and particulate matter precursors. Other available treatment options, such as thermal and catalytic incineration require temperature intensive inputs and form additional greenhouse gases. Hence, an inexpensive alternative technology is needed to eliminate these air pollutants. This research investigated the catalytic oxidation of toluene vapors using novel dispersed nano catalysts derived from new preparation method. The combined impregnation (IMP) and deposition-precipitation (DP) was used to prepare supported transition metal oxide catalyst over commercial and... 

According to global improving consumption of distillate products, like gasoline and diesel, reduction in light petroleum production and growth in exploring and extraction of heavy and sour petroleum, changing in refining structure of worldwide oil refineries is necessary and it is crucial to apply special processes for refining, conversion and cleaning of these heavy and extra-heavy petroleum. Gasification of these fuels, i.e. partial thermal oxidation of feed in the presence of gasifying agent (air, oxygen, steam or mixture of them) in the gasifier, is one of the new ways to convert heavy fuel oil to synthetic gas (syngas), that this gas can be used widely in downstream processes. Here,... 

Existing processes to improve the quality of heavy oil cuts catalytic converter hydroconversion can be mentioned in the slurry phase. This process is usually done in the temperature 440˚C to 470˚C be a heavy craking led to the production of light weight thermal feed can be more. With more products light, adverse reaction can also lead to the formation of coke be. Coke formation of secondary radical reactions can be feed from cracking of heavy compounds. Coke production is to eliminate or limit the ability of homogeneous catalysts (eg sulfide Molybdium) about 600-1000 ppm disposable food adds to be used. The main role of catalyst in the stable radicals fail thermal compound feed is heavy. The... 

Fossil fuel are energy resources in decline. In recent years, fuel cell have become as a source of energy to replace conventional systems .Among the various types of fuel cells, PEMFCs (proton exchange membrane fuel cells) possess a series of highly advantageous features such as a low-operating temperature, sustained operation at high-current density, low weight, compactness, potential for low cost and volume, long stack life, fast start-ups and suitability for discontinuous operation. Water management is one of the most critical and challenging problems. There is a delicate balance between the membrane hydration and avoiding cathode from flooding. Cathode flooding occurs when the water... 

Sulfur compounds are very undesirable and result in Corrosion in metal equipment, air pollutions and poisoning of refinery Catalysts such as reforming Catalyst. Therefore, application of Hydrodesulfurization (HDS) process in order to decrease the amount of sulfur in petroleum cuts has a great importance. HDS process is the most usual and efficientmethod for sulfur removal. In this method sulfur compounds at vigorous operating conditions such as high temperature and pressure in the presence of catalyst react with hydrogen and produce hydrogen disulfide and hydrocarbon. Sulfided Co–Mo catalysts are widely used in this process.
The aim of this study is to prepare and improve CoMo/γ-Al2O3... 

Crude oil is naturally not applicable to the refining processes to obtain important products. Most of the crude oil refining process produce heavy hydrocarbons that are not used much in the same way. More refineries are looking for a process to remove the heavy components and converts these materials into valuable material. There are different process for upgrading heavy residual oil. One of the main processes in residual upgrading is Delayed Coking. The high flexibility to the different feeds and no need for a catalyst, causing a shift in the approach to the refinery for processing heavy crude oil by Delayed Coking. The aim of this project is calculated the sulfur content and and yield of... 

Du to depletion of conventional petroleum reserves, the oil industry is faced with the challenge of developing technologies for processing heavy crude oil and petroleum residues that contain large amounts of asphaltenes and heavy metals including vanadium, nickel, and iron. So increasing need for processing of petroleum residues and full advantage of them in cases such as catalytic cracking and hydrogen units and also high-grade coke production in industries such as aluminum to be felt. In this work we used the vacuum distillation residue of Abadan heavy crude oil refinery in a solvent deasphalting (SDA) process at different temperatures (60 to 120 °C), pressures (5 ,7 and 9 bar), solvents... 

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... 

There are many archeological sites, historic building monuments and inscriptions in Iran and other countries in the world which have been damaged by environmental as well as biological causes. Lichens are one of the biological causes which, through their growth, bring about change and damage to the stones. Different methods, each of which has both advantages and disadvantages, have been used in order to deal with the problem. Since there are many historic buildings in our country which have been damaged by different biological causes including the lichens, doing a research on the topic seems to be quite significant and necessary. The Persepolis is among one of the most important historic... 

Treatment of landfill leachate with membrane bioreactor (MBR) in lab and pilot scale have been studied in this research. MBR biological adaptation procedure at start of biological treatment, choose of membrane materials, membrane production with highest treatment performance and lowest membrane foaling have been studied. Mixed liquor suspended solid of MBR at the start of adaptation period was 3000 ppm and at the end of this period became 7000 ppm, microbial community has been changed in this period. Number of microbial species were reduced and number of these adapted species were increased. Five membranes were prepared with different concentration of PVDF polymer, solvent and non-solvent to... 

Increased photo catalytic activity of NiO and 〖Co〗_3 O_4 were obtained by Ni〖Co〗_2 O_4 synthesizing and supporting functionalized multiwall carbon nano-tubes via calcinations followed by hydrothermal precipitation. NiO, 〖Co〗_3 O_4 and Ni〖Co〗_2 O_4 were prepared in the same procedure exactly for the subsequent photo catalytic activity to be compared to Ni〖Co〗_2 O_4/MWCNT later on. The photo catalytic degradation of Reactive Red 120 dye as a deazo organic pollutant model was used for experimental photo catalytic performance analysis. The CCD method was applied for experimental designing, modeling, and optimizing the operational parameters of the photo catalytic degradation of RR120 using... 

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... 

Dimethyl Ether (DME) is a pure and economic fuel which can be used as a suitable alternative for diesel fuels. Two processes are traditionally used for DME synthesis: producing methanol from synthesis gas and then dehydrating it to DME (direct process), and converting methanol into DME in a catalytic dehydration reactor over a solid-acid catalyst (indirect process), in which the indirect process seems to have economical advantage. In this research, the γ-Al2O3 catalyst was synthesized through precipitation process and then characterized by powder X-ray diffraction (XRD) and porosimetry analysis. Afterwards this catalyst was utilized in methanol dehydration reaction in a slurry reactor. Next,... 

In present work, we fabricated novel heterojunction magnetic composite and the goo visible-light-harvesting photocatalysts through integration of ZnFe2O4 and MIL-53 by facile solvothermal method. To understand physical and chemical structure prepared material and morphology of samples, The XRD,FTIR, FESEM, DRS and VSM analysis were carried out. The ZFO/M53Fe/vis-light system reveled 92.3% dye degradation which enhanced photo catalyst reactivity for the decolorization of Direct red 23 as anionic dye under irraditation of LED lamp through AOP environment friendly technology, which are significantly higher than those of pure ZFO and M53Fe semiconductors. more ever ,aforementioned composite... 

due to high mineralization rate of Zinc oxide، chemical and physical stability, non-toxicity and low price as the most promising photocatalysts studied, although its use is not too satisfactory. Because of the wide energy gap(3.2 ev) and for photocatalytic activity needs to UV light Unfortunately, the solar spectrum is made up only 5-7% of UV light, while 46-47% is the spectrum of visible light and infrared. Doped zinc oxide nanoparticles with metal and non-metallic atoms could increase the photocatalytic properties under visible light irradiation. In this research, nanoparticles of zinc oxide was doped by fluorine as Dopant. The results showed that photocatalytic activity of the modified... 

During fuel combustion, aromatic sulfur compounds in energy fuels convert into sulfur oxides, which cause major environmental problems such as acidic rain, global warming, and air pollution. Absorption desulfurization is one of the promising and economical methods to remove these sulfur compounds from fuels. Metal-organic frameworks (MOFs) are a class of nanoporous materials that are of interest for use as adsorbents due to their high specific surface area, unique surface adsorption properties, high adsorption capacity, tunable porosity, flexible dynamic behavior, and diversity in functional and metal groups. In this research, we first synthesized five metal-organic frameworks, namely... 

Wax deposition crude oils, with high pour point causes, many problems arise in production, transfer and storage. In this project, wax appearance temperature of three samples of crude oil caculated, using techniques viscometer. Maximum absolute error on oil.no2 was with a value of 0.559% and the results had in good agreement with experimental data. By using the rheometer MCR301, for three crude oil samples, steady shear tests and sweep time tests was done. Flow diagrams were obtained. According to wax appearance temperature (WAT) of each samples, diagrams shear stress versus shear rate are nonlinear at low temperatures than WAT. Crude oil shows non-newtonian behavior. Arrhenious model,...