Sharif Digital Repository

Capturing the atmospheric CO2 and turning it into value added products is a topic that has been extensively studied in recent years. One of the methods through which CO2 is valorized is via converting it into carbon nanofiber, CNFs. CNFs can be an important material in future human activities due to its valuable properties such as wide range of electrical conductivity, their superior flexibility and strength, But it is currently obstructed in use due to the high cost of manufacturing and the complexity of the synthesis. Furthermore, in today's world, human life is heavily influenced by greenhouse gases, and avoiding emitting gases like CO2, is almost infeasible. This thesis provides an... 

In this thesis, ionic liquids and polymeric ionic liquids were investigated as solvent and support for immobilization of molybdenum and palladium catalysts. Three newly synthesized room temperature ionic liquids containing molybdate anion, [DMIm][MoO2(NCS)4], [RPy][MoO2(NCS)4] (R = butyl or decyl), and previously reported [BMIm][MoO2(NCS)4] were used as catalysts for the reduction of sulfoxides. For facilitating the recyclability of the catalysts, the ionic liquid solvents, [RMIm][PF6] and [RPy][PF6] (RMIm=1-n-alkyl-3-methylimidazolium, RPy= 1-n-alkylpyridinium), were applied to immobilize molybdenum catalysts. These catalysts showed high catalytic activity for sulfoxide reduction in this... 

In this study, two approaches were applied for estimating Minimum Miscibility Pressure (MMP). An oil sample from Yadavaran Field has examined by means of Carbon Dioxide Gas, South Pars Gas, and Association Gas in experimental approach. The experimental method used for estimating MMP is Slim-Tube. This kind of method is applied in industry widely. The results indicate that the MMP of Carbon Dioxide is low which denotes that the gas is even miscible around the Bubble Point Temperature of the oil sample. Moreover, the MMP of Association Gas and South Pars Gas is 3962 and 5150 psia, respectively. In simulation approach, Cell to Cell simulation method is used to estimate the MMP of the oil sample... 

In recent years, carbon dioxide is used for enhanced oil recovery of heavy oil. Steam Huff and Puff is one of the enhanced oil recovery methods used for heavy oil. In this study liquid CO2 was used as an injecting fluid instead of steam. In this paper a series of experiments were performed to demonstrate the effect of carbon dioxide injection pressure on huff and puff process. The experimental data are used in lab scale model simulated with commercial simulator Eclipse 300 to investigate the effect of soaking time, injection pore volume and rate of injection on the heavy oil recovery. Result of experiments showed that huff and puff process under miscible pressure condition gives the most... 

Asphaltenedeposition is a major problem during natural depletion and EOR processes due to formation damage issues. It is necessary to reveal asphaltene deposition mechanisms and its effective parameters to prepare an acceptable prevention strategy. Therefore, different natural depletion and EOR experiments must performed on core samples. In this research, Effect of CO2 injection on asphaltene deposition phenomena has been surveyed. Two carbonate core samples and one sandstone core sample was used in experiments. The oil used in these experiments was recombinedoilfrom one of Iranian offshore oilfield.In order to estimate permeability reduction during experiment, injection of oil and CO2 was... 

Most of the Iranian oil reservoirs are reaching end of their natural production life, hence they are suitable candidates for EOR common processes like gas injection and WAG injection. Studies have shown that gas and WAG injection can be applied for optimal oil production. Past studies have been mainly on gas and WAG injection in immiscible or fully miscible conditions and there is a limited amount of data available on performance of these methods in near miscible conditions. Miscible injection is not feasible in old Iranian oil reservoirs due to their depleted pressure. Moreover injection in lower pressures is attractive from both economical and operational standpoints since this reduces the... 

A simultaneous water and CO2 injection study using sandstone cores with 21°API Sarvak (Azadegan field) oil has performed to evaluate oil recovery under four injection modes: secondary immiscible, secondary near-miscible, tertiary immiscible, and tertiary near-miscible. It is demonstrated that swag injection (secondary and tertiary) is an effective method for the recovery of significant amount of oil or residual oil from water-flooded porous media, but there is always some bypassing (at the pore level) of the oil due to topological effects, water-shielding and dead-end pores. In non-homogeneous porous medium, oil recovery is depending to SWAG ratio in immiscible and near-miscible conditions.... 

By continuous decreasing the fossil fuel energy resources and increasing demand of such energies on the other hand with decreasing exploration of the new ones, production from these limited resources are in grate consideration. As a few percentages of the oil recovers by primary oil production and also remaining a lot of oil after water and gas injection in the secondary oil recovery process, causes that new methods to increase the oil recovery has been proposed. Water injection is a simple and common method in enhanced oil recovery process. Also water alternating gas injection and simultaneous water and gas injection causes considerable increase in oil recovery. Recently utilization of... 

Damming projects always have been important while construction, operation and even demolition due to their major effects on society, environment and economy. Although researchers have focused on one or a few phases of construction projects to develop sustainable infrastructures, the research community has to consider long term effects of developments too. There are a variety of such effects that ignoring them will cause construction of not convenient infrastructures i.e. air pollution and over-consumption of energy resources while construction, operation and demolition. Therefore, it is suggested to consider life cycle assessments to include all bad effects in all phases of a project. Dams... 

Due to the wide application of plate-fin heat exchangers in various industries such as the petrochemical industry, aerospace industry, air conditioning systems, separation and liquefaction of gases, especially natural gas, boiling, condensation, and transportation industries, proper design of these heat exchangers is necessary. Most of the previous researches in the field of heat exchanger modeling has been done in single-phase mode. The two-phase modeling has been performed, often thermodynamically, and the effects of turbulence and surface tension have been ignored. Thus, in the present study, numerical modeling of the two-phase plate-fin heat exchanger is presented. In this project,... 

In recent decades, the concentration of carbon dioxide in the atmosphere has increased. Carbon dioxide is a greenhouse gas that raises the Earth’s temperature, and it can endanger life on Earth. This study uses the 6.2 version of the Regional Atmospheric Modeling System (RAMS) with its simple biosphere model (SiB-2) to simulate and forecast the concentration of carbon dioxide over the Daintree rainforest in Australia. This analysis helps to better understand the interaction between the biosphere and the atmosphere. Results of the carbon dioxide simulation were compared and validated with the observed values of the satellite product (MultiInstrumentFusedXCO2). Based on effective parameters,... 

In this study, a comprehensive 2D mathematical model has been developed for the simulation of physical and chemical absorption of carbon dioxide in hollow fiber membrane contactors in the presence of nanoparticles. The model were developed by considering molecular diffusion in radial and axial directions as well as non-wetting conditions. Carbon dioxide absorption was simulated from a gas mixture containing carbon dioxide and air, that flows in the shell. Also, absorbent containing nanoparticles flows in tube side and counter currently. Effects of presence of nanoparticles were modeled by taking into account two prominent mechanisms proposed in the literature for mass transfer enhancement in... 

Nowadays, the reduction of crude oil quality and the growth of environmental restrictions are the main challenges in oil refineries worldwide. The high demand of lighter refinery products and the shrinking market of the heavy products, highlighted the role of heavy residues conversion technologies.Gasification technology consumes these heavy refinery residues and produces clean syngas. By this way and the integration of gasification with power generation cycles, more value added products such as electrical energy, steam and hydrogen can be provided. For this aim to be achieved, three different scenarios are developed and investigated in this project. The first scenario includes the... 

Considering the drastical increase of greenhouse gases in the atmosphere, especially carbon dioxide, reduction of these gases seems necessary to combat global warming. Fossil fuel power plants are one of the main sources of CO2 emission. In this paper, CO2 capture from a natural gas fired steam cycle power plant using oxy-fuel combustion technology is studied. The Integrated Environmental Control Model (IECM) developed by Carnegie Mellon University was used to evaluate the effect of this capture technology on the plant efficiency and economic parameters of the system. Since the oxygen production plant, CO2 capture and transport are cost and energy intensive, the cost of electricity generated... 

One of the most important factors in global warming is greenhouse gases such as carbon dioxide. Separating carbon dioxide from industrial activities such as fossil fuel power plants and storing it in the underground water can help combat the global warming challenge. In this research, numerical modeling of carbon dioxide sequestration in the aquifers under isothermal conditions is investigated. The process of storing carbon dioxide in aquifers consists of four main stages. In the first stage, the injected carbon dioxide accumulates into the aquifers under the impermeable bed. In the second stage, some carbon dioxide is trapped by the capillary forces inside the porous media's pores. In the... 

Due to a rapid growth in the consumption of fossil fuels, the emission of greenhouse gases has multiplied in the atmosphere in the past few decades. This issue can directly affect on the rise of global temperature. Because of the intensification of the global warming, international organizations are looking for ways to reduce the greenhouse effect. One of these methods is injecting and trapping greenhouse gases, especially carbon dioxide, resulting from the operation of power plants and other large industries and preventing it from entering the atmosphere. The injection of carbon dioxide in underground salt water reservoirs can have various effects such as mechanical, hydraulic, thermal, and... 

Greenhouse gas emissions into the atmosphere have multiplied with the increase in fossil fuel consumption, which directly affects global warming. Global warming has other undesirable consequences such as rising sea water level and declining snow cover. To reduce greenhouse gases in the atmosphere, researchers have studied various ways, one of which is carbon dioxide injection into underground formations, which has a significant effect on reducing the amount of these gases in the atmosphere. Existence of high volume underground reservoirs with suitable conditions for gas injection to prevent gas escape has made it a widely used and effective method. Despite many advantages of this method, it... 

Carbon dioxide is one of the most significant greenhouse gases in biocycle. This gas makes the equilibrium temperature by absorbing IR radiations on the earth. It is the reason that prevent the earth from freezing. Increasing CO2 emissions in atmosphere, makes problems such as global warming. According to the Kyoto Protocol, all the countries attended to this protocol, must decrease greenhouse gases emissions. Although H2 fuel is one of the best alternative fuel against fossil fuels, the most important industrial process (steam-methane reforming) produce CO2 as by-product. Thus, gas separation has a prominent role in industrial processes such as CO2 capture and H2 purification.Today, gas... 

Thermodynamic modeling is a useful method for predicting of asphaltene precipitation due to various reasons, such as CO2 injection, mixing of different oils in oil storage and pressure changes. However, the application of solid model and thermodynamic micellization model, for prediction of asphaltene precipitation under gas injection condition, hasnot been improved. In this work, two computer codes which are based on two different asphaltene precipitation thermodynamic models, 1-Thermodynamic Micellization Model and 2- Solid Model, have been developed, and, used for predicting of asphaltene precipitation data reported in the literature as well as the experimental data obtained from high... 

Carbonate matrix acidizing using hydrochloric acid which causes CO2 generation is one of the most popular well stimulation techniques in recent decades. Lots of the wormhole propagation models developed for laboratory scale, assumes that the cores are fully saturated with aqueous solution and no CO2 gas is produced. Final purpose of this research is to develop a geochemical model describing equilibrium composition of a 3 phase system of acidic solution-gas-rock accurately in common pressure and temperature conditions of carbonate matrix acidizing to obtain main inputs of acid reactive flow in porous media from it. In this regard, concept of the “extent of the reaction” is defined and after...