Sharif Digital Repository

In this study production of bioethanol from corn fiber that is a lignocellulosic material is investigated. Experiments were performed in a membrane bioreactor. Bioethanol is a second generation biofuel that is considered recently because of the decrease in oil production and pollutions caused by fossil fuels.The feed was corn fiber which is considered suitable due to its low cost and availability in my country. Corn fiber is composed of cellulose, hemicellulose and lignin. We should increase cellulose fraction by pretreatment methods to get a higher conversion rate into bioethanol. We did this by acid pretreatment and the fraction was reached to 41%. In most of previous work experiments were... 

In this study the kinetics of extraction of various hydrocarbons from crude oil using supercritical CO2 has been studied experimentally. The effect of parameters such as temperature (35, 45, 55, 65 °C), pressure (90, 110, 130, 150 bar), initial volume of crude oil (16, 19, 22, 25 mL) were investigated. Flow rate of gas has been recorded dynamically. QUALITECH 4 and MATLAB neural network softwares have been used for designing the experiments and modeling the final results, respectively. Pressure has a direct effect on extraction yield and by increasing it, heavier fractions could be obtained. On the other hand, the effect of temperature is more complicated, by increasing the temperature, the... 

The aim of this research is to model the separation and transport of multi-component gas mixture through a nanoporous membrane by using pore network models (PNM).
The first part of this project represents the membrane simulating by means of the PNM. A three-dimensional network is used to represent the membrane’s pore space and it consists of two parts; pore and throat. The pores are the main parts of the network and their diameter is characterized according to the pore size distribution of the membrane. Every throat connects two pores and the number of throats which is connected to each pore is named "coordination number". Using a variety size of pores and throats leads to production of... 

The purpose of the present project is to construct and improve the quality of an absorbable membrane using a supercritical process and study the effects of the operative parameters. Today, usage of biodegradable polymers is intensively increasing and these kinds of polymers are used as drug delivery carrier and tissue engineering medium. A biodegradable membrane is suitable for this goal. In this study Poly Ethylene Glycol (PEG) is used as the biodegradable polymer. Gas anti-solvent (GAS) method was applied for the production of the membrane. The used anti-solvent was Supercritical Carbon Dioxide. In order to study the effects of the operative parameters on the structure of the produced... 

This study has concentrated on preparation of mixed matrix membranes (MMMs) in order to improve the separation performance of the neat poly(amide-12-b-ethylene oxide)(Pebax1074) membrane. Pebax1074 and zeolite SAPO-34 were used to fabricate MMM for the first time. Micro-size SAPO-34 was added to polymer matrix up to 35wt% based on polymer weight; even though at this high loading percentage the prepared membranes were not stable enough to be tested for characterization and gas permeation. The obtained results showed more than 30% increment in CO2 permeability, along with slight growth and reduction in N2 and CH4 permeabilities, respectively for 30wt% zeolite content membranes. Permeability... 

The aim of this project is to achieve a semi permeable high flux membrane with a reasonable salt rejection for the treatment of low osmotic pressure water. A thin film composite membrane consists of three polymeric layers was studied in this project. These layers were polyester support, polysulfone sub layer and polyamine selective layer. The polyester support provides the mechanical resistance against the operating pressure. The polysulfone sub layer provides the suitable area for polyamide synthesize, and the polyamide layer is the selective active layer of membrane.
The resistance to water penetration in sub layer was reduced first and then, the pores in the polyamide layer refined by... 

In this project, modification of reverse osmosis membrane was investigated in order to reduce the biofouling in treatment of brackish water. Furthermore, the technique which is used to attain the favorable results is graft polymerization to modify the membrane’s surface with grafting acrylic acid as hydrophilic monomer onto polyamide exploited as last layer in reverse osmosis membrane. This technique is a free radical grafting, andfree radicals which are needed for grafting are provided by the redox system potassium persulfate-sodium metabisulfite which was used as initiator. To figure out the best concentration of acrylic acid, initiator and process time in order to achieve a new membrane... 

The consumption of fossil fuels (oil, gas and coal) increased the concentration of greenhouse gases in the atmosphere that cause increase of earth atmosphere temperature and lots of environmental problems. Using appropriate alternative energy sources is one way to control this emission, while considering energy infrastructures shows this is a far solution. An early way for decreasing the emission of greenhouse gases in the atmosphere is injection of CO2 in geological formations. Since approximately 50 years ago some researches in this area have been developing. The most important limit of these projects is its costs so it is wise to combine them with gas injection projects in gas and oil... 

Partial oxidation of methane (POX) is one of the most common processes to produce synthesis gas. In this study the kinetics of this process is examined and some reduced mechanisms are introduced to model it in this study. The experimental data from Research Institute of Petroleum Industry are used as reference experimental data. Inlets of this reactor are oxygen and methane with equivalence ratio between 2.53 and 2.9. Moreover, the experimental results of previous studies with the air as the oxidant in equivalence ration between 2.4 and 2.6 are used as basis for comparison of simulation results. During the first step, partial oxidation of methane in non-catalytic porous media is simulated by... 

Due to population growth, per capita change and heterogeneous distribution of water resources, forecasts demonstrate that more than 66% of the world's population will experience water scarcity by 2025. The major concern of desalination is their management of brine, with concentrations and their associated components more than twice the input concentration. Also, when extracting oil, per 1 oil barrel, about 7 to 10 barrels of high saline water are produced. One of the most common methods for disposing of brine is direct discharge into the environment, which, due to its destructive effects, creates serious threats to marine ecosystems. Therefore, it is necessary to desalting these high saline... 

Permanent Downhole Gauge (PDG) has been employed since 1990s to acquire more information and better access to well and control production. PDG provides huge amount of pressure transient data during well test operation and production. However, such data are encountering with various noise and outliers. The noise and outliers can cause misleading and misinterpretation results. Therefore, denoising and outlier removal are two imperative steps before pressure transient analysis. The conventional denoising methods are mostly based on wavelet thresholding methods that preserve mean of data and have good performance when noise distribution is Gaussian distribution. However, noise distribution... 

The major obstacle in using natural gas as a clean and abundant fuel in transportation industries is the low density of energy obtained from its combustion. Adsorbed Natural Gas (ANG) is a useful method to increase the energy density and store the natural gas. The lower cost and higher safety have made it different from the other storage technologies. In addition, ANG can be useful to solve the lack of gas in the peak of consumption. Among all adsorbents, Activated Carbon (AC) has shown the highest adsorption capacity of natural gas. In the present project, walnut shell has been used as the precursor in the chemical synthesise of AC. The main effective factors in chemical activation, such as... 

In this research incorporation of SAPO-34 zeolite filler into polycarbonate membrane was investigated for fabrication of mixed matrix membrane (MMM). The main purpose of addition of zeolite in polymer matrix is to enhance the separation properties of pure membrane by means of the selective pores of SAPO-34. SAPO-34 possesses pores with proper size for separation of CO2 from CH4 by molecular sieving mechanism. Pure polycarbonate membrane and PC/SAPO-34 MMM was prepared by solvent evaporation method using dichloromethane as solvent. Zeolite loading was varied between 5-30%wt. First of all, polycarbonate was characterized by DSC, FTIR and viscometer analysis in order to determine all the... 

Gas pollutants are included volatile inorganic compositions and odorous materials, which are harmful and dangerous for environment and human health. There are several methods for removing gas pollutants such as physical, chemical and biological methods. In this work, we discuss about ethyl-mercaptan adsorption in LPG by ZSM-5 zeolite and in use of micro systems (micro channels). This work is also concerned about micro channel coating by ZSM-5 and NaY zeolites on glass and the method of coating with (3-Chloropropyl) trimethoxysilane linker. After selecting the appropriate method for zeolite coating, we proceed to micro channel coating. In this research, four different designs of micro channel... 

Air pollution caused by industrialization is the problem which adversely affects human life. Among air pollutants suspended particles, especially particles smaller than 10 microns (PM10), for their high concentration in air in large cities are the major index as air pollutant. Due to their small size, PM10 can penetrate into the aspiration organs causing harmful effects. The objective of this work is to develop an Artificial Neural Network (ANN) model for prediction of short-term concentration of PM10 in the city of Tehran. Complex mechanism of reactions, numerous types of pollutant materials produced from transportation and industrial activities, variety of sources, difficulties in data... 

In this study, fabrication of polymeric nanocomposite membranes for separation of olefins from paraffins was investigated. Silver nanoparticles were prepared by Polyol chemical reduction method. At first, dense ethylcellulose and ethylcellulose-silver nanoparticles membranes were fabricated by solvent-evaporation method. Then Asymmetric EC and EC-silver nanoparticle nanocomposite membranes were fabricated by dry/wet phase inversion method as a means to improve flux rates and olefin selectivity in olefin/paraffin separations. The membranes properties and The Effects of incorporating nanoparticles in polymer matrix in low concentration on gas permeability and membranes morphology were... 

% of human blood makes up of plasma, that this plasma is a rich source of proteins that can be used as biomarkers for a variety of clinical diseases and laboratory research, therefore, it is necessary that the plasma be separate by a high purity percentage. Using a centrifuge It is a common method used to separate plasma from blood, but because it requires large equipment and a large volume of blood, as well as stress caused by centrifugal force, increases the probability of damage to the biomarkers, so it has been tried today that Use methods that are easy to transport and require a small amount of blood. The idea of using the microfluidic device has been put forward for the purpose of... 

Nowadays, radical increase in energy consumption guides humankind to find and harvest some alternative energy resources. Between the energy resources that have ever been known, Solar Energy is the most traditional one and Solar Water Heaters (SWHs) are the most ancient tools that have been used to store this energy up to now. Regarding this issue, many researches have been done to investigate different aspects of SWHs and the most conventional type was Thermosyphon SWH system. In this study, our aim is to investigate the influence of Pulsating Heat Pipes (PHPs) application as a heat transfer tool to convey absorbed solar energy to hot water reservoir of a SWH. In order to do this research,... 

In this thesis, the application of solar energy in the steam injection as a thermal enhanced oil recovery (TEOR) is evaluated. The motivations of this project are using a renewable energy, suitable solar potential of Iran, successful experience in the world, undeveloped heavy oilfield reservoirs in Iran. This application is investigated by three aspects which are:Reservoir Engineering aspect: the heavy oilfield are determined and then screening for selection good candidate of steam injection are done. One of the reservoirs is analyzed by simulation and optimization the steam injection to determine how much it’s production will be improved by using steam injection (contionous and cyclic)... 

Regarding decreasing resources of fossil fuels and their increasing costs in addition to their environmental pollutions, today, producing bio fuels from wastes such as lignocellulosic materials is of great interest. A fundamental stage in conversion of lignocellulosic materials into bio fuels, such as bio ethanol, is the enzymatic hydrolysis of these materials to produce reducing sugars. Researches have shown high costs of this stage. Optimization of enzymatic hydrolysisconditions is a major step in economization of this process.In this work corn hull is used to produce glucose. Corn hull is a kind of lignocellulosic material that due to high carbohydrate content is used as substrate. Our...