Sharif Digital Repository

Formation damage in oil and gas wells is mainly induced by drilling operations. Filtrate and particle invasion into formation as the sources of this damage caused serious problems, e.g. reduction of production rates. Therefore numerical modeling of this phenomenon helps us to better understand the process, and as a result, control and reduce formation damage associated with this impairment. In this research, a model to estimate the invasion depth and damage of mud filtrate from water-based mud is presented. Filtrate invasion into the formation is investigated by convection-diffusion equation with regard to dispersion term. The invasion depth is obtained from mud filtrate profile in the... 

Chemical dispersants applied to the surface of Persian Gulf during the oil spill in 2010 were more than one million gallons. Following the addition of dispersants, oil mixes below the seawater surface and can be degraded or dissolved into the water column. The aforementioned condition is a perfect opportunity for degradation of organic pollutants using Ultraviolet light emitting diodes Advanced Oxidation Processes (AOPs). These methods are based on activation of oxidants such as persulfate and hydrogen peroxide to generate extremely reactive radicals. Dispersants would increase the degradation rate by providing more active area (homogenous solution) for these radicals. AOPs have shown to... 

In the current study, the dispersion of four major air pollutants, sulphur dioxide, nitrogen oxide, carbon monoxide, and particulate matter from gas flares of an oil field, in Iran, was investigated for year 2011 by application of a conventional steady state Gaussian dispersion model, AERMOD. Two scenarios were applied in modeling, first application of flare parameters based on technologies that exist and the other one using new technologies in flares such as steam assisted with better combustion efficiency. Due to the complexity of meteorological parameters in modeling area, CALPUFF model was used in this study. CALPUFF which is a more advanced model that considers the effect of... 

In order to actualize the development of sustainable and smart cities, load disaggregation plays such an important role for energy consumption optimization, load response, and distributed energy production network optimization. Researchers have observed that non-intrusive load monitoring is a low-cost method because it doesn't require multiple sensors, but it has issues with algorithm complexity, algorithm variety, and algorithm accuracy dependence on factors like data collection frequency and the type of energy-consuming equipment. In this research, an effort has been made to evaluate how sensitive certain algorithms are to adjustments in the frequency of data collection and the duration of... 

About 6.5 million people die from air pollution annually, of which 5.5 million are from the Asian continent. By considering reduction of life span and external costs associated with the emission of air pollutants, the importance of environmental impact assessment and managing the reduction of pollutant emissions becomes even more important. Meanwhile, the largest share (85%) of pollutant emissions is related to the supply and demand sectors of energy carriers. Therefore, the design and development of the environmental impact assessment system of energy flows is a necessity in the process of sustainable development of the energy sector.A key policy challenge in Tehran megacity is to curb high... 

The main aim of this project is to develop a model for risk assessment of energy service companies (ESCO) using energy efficiency and emission trading markets. For this purpose, structure of the market has been developed and then by explaining the interactions between ESCO and other members of the market, ESCO's cash flows have been determineded. In the next stage, probability distribution of the cash flows have been extracted and risk assessment have been performed. The differences in energy prices coming from subsidies is the foundation of this market. In this market, ESCO will sell the saved energy rights which has been achieved in the low price level sector to the other sector with high... 

The dispersed phase holdup is one of the important parameters in the design pulsed column and set the column diameter, height and characteristics of flooding and mass transfer. High efficiency and low space requirements of these columns cause is particularly in the nuclear industry, Due to the possible presence of radiation and the need for protection against radiation, considered and used. In this project, the dispersed phase holdup and mean residence time in a pulsed disc and donut column in a semi-industrial scale using radiotracer and shut down methods compared and presented for water-kerosene system. Also axial dispersion coefficient in the column using radiotracer methods is calculated... 

Distributed generation (DG) and its utilization have some benefits and risks for its owner and power network. From owner perspective, benefits of DG include selling energy, reducing costs related to fuel, and other economic benefits. However, there are some risk factors for the owner including risk of supplying fuel, risk of selling generated power, and other risk factors related to establishment of the DG unit. Utilizing risk-reduction tools such as signing agreements for selling power, purchasing fuel, and related economic tools are necessary for risk management of the owners of DG units. The purpose of this thesis is to investigate the economic situation of the DG units and optimize the... 

Climate change and energy security are key drivers for future energy policy. While energy security has been a pillar of energy policy for about a century, concern about climate change is more recent and is bound to radically change the landscape of energy policy. Policy makers are now under increasing pressure to address these twin challenges: to develop cost-effective policies that will both ensure the security of our energy system and reduce greenhouse gas emissions.
Main Effort in this Project is to construct an integrated model of Iran’s energy system to serve as a policy analysis tool, by which policymakers are able to identify the future effects of a wide range of policies in... 

Increase in electricity demands and expansion cost of the power system as well as raising more concerns on environmental issues have led to increasing attraction towards Distributed Generation (DG) application in power systems. DG is generally defined as small generation units, ranging from several KW to several MW, that are installed on the distribution network. In Iran, the energy generated by DG units is purchased by Tavanir or distribution companies through guaranteed fixed-price purchase contract. The contract price imposes substantial effects on the cost and benefit of DG owners as well as those of the distribution company (DisCo). A logical and fair pricing model can provide more... 

This report models the electricity supply network by means of the ESM software. In this model, the distribution company obtains its final users’ electricity demand from three sources: distributed generation plants owned by private sector, distributed generation plants owned by the distribution company and buying from electricity market (Over distribution network). According to the model, the optimum point of operating the network is a point with maximum profit, minimum waste and environmental effects. The optimum point of supply minimizes the network wastes to an optimum extent. In this model, the distribution company can supply the extra electricity to the electricity market, provided that... 

During various stages of processing uranium in Isfahan’s UCF plant, liquid waste containing uranium compounds, is directed to evaporation lagoons. Gradually, a considerable amount of precipitation will form at the bottom of the lagoons. Since the concentration of uranium in evaporation ponds is relatively high, it seems that in addition to environmental issues, recycling uranium from existing pools is also economical. Uranium may be recovered from an aqueous solution by precipitation, solvent extraction and ion exchange. The solvent extraction is the best option for our purpose because of simple operation without increased consumption of heat or chemicals. It is also preferable when large... 

Dispersed phase holdup has been measured in a 75 mm diameter pulsed disc and doughnut extraction column for three different liquid-liquid systems. The effects of operational variables such as pulsation intensity and dispersed and continuous phases flow rates on holdup have been investigated and found to be significant. The existence of three different operational regimes, namely mixer-settler, dispersion, and emulsion regimes, was observed when the energy input was changed. The results indicated that the characteristic velocity approach is applicable to this type of extraction column for analysis holdup in transition and emulsion regions. Empirical correlations are derived for prediction of... 

The objective of the present research work has been the development of a model of optimal distribution electrical energy which may include distributed generators. Electrical distribution company has the option of receiving electric power from distributed generators owned by customers (Private Companies), DGs belonging to the electrical distribution company and purchase of power from market (high voltage network). The electrical distribution company would alternatively be able to sell surplus of its generation to the power market (high voltage network). The model of distribution system depicts the flow of electricity in each hour interval. The restrictions and bounds are the flows in each... 

Nowadays, air pollution has become one of the biggest problem of large cities and has numerous negative effects on the environment and people's health. The present research examines how various types of pollutants are distributed in an urban environment, depending on the type of arrangement in different places. Razaviyeh town (including nine 15-story buildings) in the 9th phase of Pardis new city in Tehran has been studied three-dimensionally here. The dimensions of each building in this complex are 12 x 13.5 meters and their height is about 45 meters. Thus, the dimensions of the computational domain used are estimated to be less than 0.02 square kilometers. In this research, computational... 

In the following research a novel method for vibration analysis of nano-structures has been presented. This method is based on equalizing the lattice stiffness to a continuous model. In this method, an equivalent continuous system is considered for each atomic lattice and for the equivalent system a modified differential equation is presented. The governing equation of the continuous system is modified in such a way that the displacement field of the atomic lattice obtained by solving this differential equation gives similar responses to the displacement field of atomic lattice. This differential equation is derived from the Taylor expansion of the displacement field about the lattice atoms.... 

Over the course of past decade, air pollution has been placed among the top issues chocking capital Tehran. Stationary source of air pollution is among the most important, but, less treated facors. On the year, 2014, Tehran’s air quality company addressed a number of projects in this very field could gain further governmental supports. This announcement could be a sign, showing the importance of this research. These researches in fact, have the potentioal to increase the authority’s decision making abilities in critical situations. As the models prognosticates future with acceptble accuracy, it leads to highly efficient dicissions. The results could also be used in demographic studies as... 

The present work is concerned with numerical simulation of spray flame for rocket combustor (MASCOTTE A-10 test case at 10 bar pressure) based on cryogen gaseous hydrogen and liquid oxygen at specific condition. This liquid oxygen and gaseous hydrogen single element combustor experiment has been the focus of many numerical studies which is representative of combustion in rocket combustion chamber condition. The purposed strategy relies on hybrid Eulerian-Lagrangian framework that continuous phase is evaluated by Reynolds average Navier-stokes (RANS) equation with quick discretization method and dispersed phase of combustion chamber atmosphere is evaluated by discrete phase method (DPM). To... 

In this work, dispersion of a spinning projectile has been reduced by modifying its configuration and using a simple open-loop guidance. The traditional nose is replaced with a new nose with controllable fins, the spin of which is isolated from the remained body using a roller bearing. To check out the dynamic behavior of the projectile, non-linear simulations has been used which were developed at preceding research projects. To carry out this project, important errors that make the dispersion of the projectile have been investigated. Then, assuming projectile is controlled ideally, an open-loop guidance has been achieved and the appropriate times for the implemention of the guidance... 

Gasoline consumption resulting from vehicular traffic is one of the most significant factors influencing the emission levels of pollutants. Since the sold gasoline at fuel stations does not necessarily translate into vehicular traffic, tracing the final consumer becomes challenging. hence, estimating the impact of gasoline consumption on air pollution is accompanied by biased results. Moreover, the COVID-19 outbreak, acting as an exogenous shock, has provided an opportunity to use data such as COVID-19 and intercity travel as instrumental variables, gasoline consumption, and emission levels, between 2018 and 2020, show unbiased estimates of the effect of gasoline consumption on air...