Sharif Digital Repository

Hydrothermal supercritical method is one of the most suitable methods for metal oxide nano powder, ceramics and mineral catalyst synthesis. Metal oxides nanopowder in its pure or mixed form has wide potential application as chemical industrial catalyst, hot Superconductors, magnetic material, gas sensors and car catalyst convertors. One of the most important metal oxides aspects of application is uranium oxide as nuclear reactor fuel is used. In addition, UO2 is selective catalyst for converting methane to methanol process and Decomposition of organic Chlorine material. In Supercritical hydrothermal method done in high pressure reactor with critical to fluid, is new method for the... 

The purpose of this study is developing the design means of a high pressure centrifugal compressor impeller for aviational applications i.e. turboshaft engines. The logic and constraints of designing a high pressure centrifugal impeller for a turboshaft engine is different from those of low pressure aerial or high speed industrial ones. This kind of impeller is deployed in a number of advanced generation of aero engines. In this study, the centrifugal impeller design tools are developed using two design methods. Then, the results are compared, validated and corrected with an existing high pressure impeller data. A number of impellers with pressure ratios ranging from 6 to 11 are designed and... 

Casing failure is one of the mainly problems of hydrocarbon fields that may cause wells out of service and impose heavy costs on oil companies. There exist many theories that may cause casing failure including: the plastic behavior of surrounding formations, the effects of reservoir depletion, over-pressured formations, weak cementing operations, fault activation, and local stresses applied on casing. In salt-rich formations, creep behavior can be the main cause of casing failure, too.The purpose of this study is to evaluate the causes affecting casing failure via experimental studies and numerical simulation with the focus on the conditions governing south-west Iranian oil fields, where the... 

Thread connections are widely used in tubular downhole equipment. Connections are usually weaker than tubulars and their failure will result in very high cost. Thread connections of downhole equipment are divided into two groups: standard connections and premium connections. Standard connections, despite being widely used, have limitations and will loose their efficiency in complex loadings. According to the mentioned limitations, premium connections have been proposed according to the existing need related to improving the strength of the structure, proper sealing and resistance to galling. One of the most obvious applications of premium connections is in downhole tubulars that are... 

With the advent and development of modern technologies, the need for energy in industrial societies has been dramatically increased. Currently, natural gas is considered as one of the most important energy sources in the world. High pressure transmission lines are widely used to transfer natural gas from wells and natural resources to industrial centers. High costs, limited results, and the potential risks of empirical experiments along with further need for problem simplification in analytical studies have led numerical methods to become the most practical tools for researchers in the safety field of high pressure gas transmission lines. Numerical simulations of explosive events require a... 

In this study, the effect of iron ore concentrate morphology on green pellet quality was studied. In order to produce concentrate with different morphology using ball mill, ball charge (20-40 %V), grinding time (30-50 min) and ball distribution (15 mm, 23 mm, 15+23 mm) was varied. It was deduced that increasing grinding time and ball charge would result in reduction of D80 but would increase Blaine number. The interaction parameters of ball distribution-grinding time and ball distribution-ball charge had significant effect on Blaine and D80. It was also observed that mixed level of ball distribution would lead to higher Blaine numbers. The equation obtained by CCD was verified by the... 

Gas injection process is one of the main methods to increase the hydrocarbon reservoirs. Minimum Miscibility pressure is a key parameter that controls the efficiency of the gas injection process. It depends on the temperature, the composition of the injected gas and the composition of the reservoir fluids. In this study, the interfacial tension of the live oil-gas system of one of the reservoirs of southwestern Iran was obtained by analyzing the Pendant drop method at 225 ° F and different pressures, and then by using the Vanishing Interfacial Tension method, the Minimum Miscibility Pressure has been computed .In this study, pure and base gases such as nitrogen, methane and injection gas of... 

Today, increasing the productivity of reservoirs is more important than in the past, while the use of nanoparticles to change the wettability of rock and increase the recovery factor from the reservoir has been considered by many researchers. Despite previous studies on the use of nanoparticles to change the wettability of rock to gas-wet, the use of nanocomposites with super gas-wet at high temperature and pressure in the crude oil-gas system has rarely been considered. In this research, several nanocomposites with different structures have been synthesized in the laboratory and nanofluids with different formulations have been used to coat the rock thin sections and measure droplet contact... 

In This thesis the properties of a compatible rubber compound for a specific chemical environment (acidic media) with high temperature and high pressure (HTHP) is studied. After primary studies, six formulations are designed on the basis of Nitrile rubber. after tensile and hardness tests at ambient temperature and 120 °C, samples putted in aging reservoir for aging tests. After that, tensile and hardness tests were performed again. Finally, by analyzing the results, the best formulation have chosen. Test results show that the NBR / PVC compound with higher filler load, has the best chemical resistance  

Water base drilling fluids are the most common drilling fluids in oil and gas operations and biopolymers are the requisite additives used in such kind of fluids frequently. Unfortunately, at harsh conditions of HPHT the polymers undergo thermal degradation which cause serious loss in fluid rheological and filtration properties. Accordingly, this will induce operational pitfalls and tremendous cost. The power of economy along with environmental regulations force us to search for reasonable chemically benign additives to fulfill this need. Nanoparticles are the most promising additives proposed in this study to address this challenge. Regarding their unique exclusive properties, they are able... 

In this work, a non-isothermal model of natural gas in pipelines including mass, momentum and energy balance equations are used as model equations for modeling and state estimation in gas pipeline systems. An algorithm is proposed to handle the discontinuities that appear in the dynamic model of a GTN. The states of GTN are estimated using the continuous/discrete form of the extended Kalman filter for two benchmarks and some heuristic rules for sensor placement in a GTN are concluded. Also, a framework for distributed and decentralized state estimation in high-pressure and long-distance gas transmission networks (GTNs) is proposed. Some heuristic rules are suggested for system decomposition... 

Because of the importance of gas-solid fluidized beds in industrial plants, many efforts have been done for predicting their behavior up to now. Generally, there are two major attitudes for describing and simulating the hydrodynamics of fluidized beds, Eulerian-Eulerian methods and Eulerian-Lagrangian metods. Both of these approaches have their own advantages and disadvantages and a lot of studies have been done to understand the nature of gas-solid fluidized beds with aid of these models. Due to fewer presumptions in the basic structure of Eulerian-Lagrangian methods such as DEM in comparison with Eulerian-Eulerian methods like TFM, these models can predict the hydrodynamics of fluidized...