Sharif Digital Repository

Plant layout and siting are the earliest steps in any process design that may have significant effects on the further required level of safety and costs. Extensive carried out studies have been published in literatures in which, the safety factor has been taken into account in the form of prediction the severity of likely accidents. Majority of these studies are based on the accident consequence and other important parameters such as the accident frequency and the density of vulnerable items have been ignored. This recent negligence may lead to over conservative designs. To eliminate this recent deficiency, quantitative risk assessment (QRA) is the best procedure than can be suggested.... 

In this study, thermal and rheological properties of nanofluids of water/carbon nanotubes, water/spherical silica nanoparticles and water/hybrid nanoparticles (hybrid of carbon nanotubes and spherical silica nanoparticles) have been investigated. To do so, carbon nanotubes have been synthesized by CCVD process and spherical silica nanoparticles and hybrid nanoparticles by wet chemical method. After synthesis of nanomaterials, nanofluids have been prepared by using SDBS as a dispersant with the concentration of 1.5 times of concentration of nanomaterials and then thermal conductivity, kinematic viscosity, dynamic viscosity and density of nanofluids have been investigated. As the results show,... 

Heavy oil reservoirs include a major part of the world’s oil reservoirs. Therefore consideration to their enhanced oil recovery (EOR) aspects has a great importance. In heavy oil reservoirs secondary and tertiary EOR methods, have an insignificant effect on oil recovery and so we’d better to use chemical methods to improve mobility and oil recovery. One of the appropriate EOR methods which has attracted a lot of attention is alkaline – surfactant – polymer (ASP) flooding which has a considerable impact on EOR from heavy oil reservoirs. In this EOR method, the low concentration of surfactant in the injecting fluid, results in a low or ultra-low interfacial tension (IFT) between residual oil... 

The appearance of water in pipe lines of the natural gas transportation would cause several problems. In this regard, disparate methods have been developed to produce and refine of the natural gas, and one of the most common method is adsorption process. In this study, modeling and simulation of the adsorption process in the packed bed of zeolite 4A has been done. This research includes four steps, first, adsorption process and all types of adsorbent were investigated. Second, using rigorous solution method, equations of mass and energy balance derived. Third, using the collocation method and MATLAB programing, system equations of mass and energy was solved. Finally, accuracy of simulation... 

Heavy oil reservoirs contain huge amount of initial oil in place in the world. Thus, enhancement of their production attracts lots of attention. Primary and secondary oil recovery methods have just little effects on the production of these reservoirs, thus, using innovative chemical methods which lead them to increase their mobility is recommended to improve their oil recovery efficiency. One of these proper and novel methods which has been established recently to enhance oil recovery is ASP1 flooding that can significantly increase oil recovery from petroleum heavy oil reservoirs. In addition, considerable numbers of reservoirs especially heavy oil reservoirs are fractured reservoirs. In... 

This study presents a novel perspective on pressure-transient analysis (PTA) of downhole-pressure and flow-rate data by use of system-identification (SI) techniques as widely used in advanced process engineering. Key features of the algorithm are that it considers the classic PTA process from a system-theoretical perspective; derives the causal structure of the flow dynamics; proposes a method to deal with continuously varying pressure and flow-rate signals contaminated with correlated noise, which estimates physical reservoir parameters through a systematic matching procedure in the frequency domain; and can cope with arbitrary (i.e., not necessarily piecewise constant) flow-rate signals....