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hydrate-formation
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Prediction of hydrate formation for the systems containing single and mixed electrolyte solutions
, Article Iranian Journal of Chemistry and Chemical Engineering ; Volume 26, Issue 1 , 2007 , Pages 35-45 ; 10219986 (ISSN) ; Rashtchian, D ; Ghotbi, C ; Taghikhani, V ; Khayat, G ; Sharif University of Technology
Iranian Journal of Chemistry and Chemical Engineering
2007
Abstract
In this work the effect of electrolytes on hydrate formation was investigated. To do so, a new model was used in predicting the hydrate formation conditions in presence of both single and mixed electrolyte solutions. The new model is based on the van der Waals - Platteeuw hydrate equation of state. In order to evaluate the values for the activity of water in electrolyte solutions the simplified version of the Ghotbi-Vera Mean Spherical Approximation (SGV-MSA) model was used. According to the SGV-MSA model the ions in the solutions are considered as charged hard spheres with different sizes. The values of the parameters for the SGV-MSA model are independent of temperature and depend only on...
Evolving a robust modeling tool for prediction of natural gas hydrate formation conditions
, Article Journal of Unconventional Oil and Gas Resources ; Volume 12 , December , 2015 , Pages 45-55 ; 22133976 (ISSN) ; Mesbah, M ; Shokrollahi, A ; Rozyn, J ; Lee, M ; Kashiwao, T ; Bahadori, A ; Sharif University of Technology
Elsevier Ltd
2015
Abstract
Natural gas is a very important energy source. The production, processing and transportation of natural gas can be affected significantly by gas hydrates. Pipeline blockages due to hydrate formation causes operational problems and a decrease in production performance. This paper presents an improved artificial neural network (ANN) method to predict the hydrate formation temperature (HFT) for a wide range of gas mixtures. A new approach was used to define the variables for formation of a hydrate structure according to each species presented in natural gas mixtures. This approach resulted in a strong network with a precise prediction, especially in the case of sour gases. This study also...
Kinetic modeling of gas hydrates formation in presence of additives using Artificial Neural Networks
, M.Sc. Thesis Sharif University of Technology ; Taghikhani, Vahid (Supervisor) ; Ghotbi, Cyrus (Supervisor)
Abstract
Many researchers were interested in gas hydrates because of their especial properties. These researches divided in two fields, thermodynamic and kinetic. The studies on first field began since many years ago, and they provided suitable results. But the investigation of hydrate formation kinetic started for 30 years ago, approximately, and according to its features such as high complexity of crystallization process and severe dependency on system, yet the comprehensive and pervasive model was not presented. At this project, after the presentation and survey of diverse models, in order to kinetic modeling of available data, among different kinetic models a reaction model selected. Then primary...
Comparative analysis of hydrate formation pressure applying cubic equations of state (eos), artificial neural network (ann) and adaptive neuro-fuzzy inference system (anfis)
, Article International Journal of Thermodynamics ; Volume 15, Issue 2 , 2012 , Pages 91-101 ; 13019724 (ISSN) ; Saber, M ; Ameri, A ; Sharif University of Technology
Abstract
The objective of this work is making comparison between thermodynamic models and data-driven techniques accuracy in prediction of hydrate formation pressure as a function of temperature and composition of gas mixtures. The Peng-Robinson (PR) and Patel-Teja (PT) equations of state are used for thermodynamic modeling and Artificial Neural Networks (ANNs) and Adaptive Neuro-Fuzzy Inference System (ANFIS) are used as data-driven models. The capability of each method is evaluated by comparison with the experimental data collected from literature. It is shown that there is a good agreement between thermodynamic modeling and the experimental data in most of the cases; however, the prediction...
Formation and Economic Study on Hydrate Technology with NGH Pellets
, Article Journal of Dispersion Science and Technology ; Volume 34, Issue 2 , 2013 , Pages 259-267 ; 01932691 (ISSN) ; Ebrahimi, A. N ; Ramazani S. A., A ; Sharif University of Technology
2013
Abstract
This study presents economic and formation investigations on hydration effects by looking at natural gas hydrate (NGH) storage and transportation processes and formation conditions. The investigation includes experiments with methane. The obtained results show that the methane formation time increased linearly as the subcooling temperature decreased. Furthermore, the economic result indicates that the energy consumption parameter is appropriate for examining resource consumption for a system that, in turn, results in optimal capital investment through the storage and transportation process of NGH. The results also show that energy consumption increases logarithmically as the hydrate...
Experimental determination of hydrate phase equilibrium curve for an Iranian sour gas condensate sample
, Article Journal of Natural Gas Science and Engineering ; Volume 9 , November , 2012 , Pages 11-15 ; 18755100 (ISSN) ; Oyarhossein, M ; Sharif University of Technology
2012
Abstract
Iran's proved natural gas reserves are the world's second largest. Mainly, because of climate changes and different reservoirs' characterizations, studying the behavior of production fluids and their transportation is essential. One of the main problems which occurs in the gas reservoirs is related to the hydrate formation while producing from a well, either in production strings or production lines (before and after choke). Effective parameters which influence the formation of hydrates are: high pressure, low temperature and water presence; and therefore, the high possibility of having this phenomenon in Iranian reservoirs is quite obvious especially in cold climates and for gas wells....
A wet cold-flow technology for tackling offshore flow-assurance problems
, Article SPE Projects, Facilities and Construction ; Volume 5, Issue 2 , 2010 , Pages 58-64 ; 19422431 (ISSN) ; Chapoy, A ; Anderson, R ; Tohidi, B ; Sharif University of Technology
2010
Abstract
Flow assurance is a major challenge in offshore and deepwater operations. Conventional approaches for preventing gas-hydrate formation involve using thermodynamic inhibitors (e.g., methanol, glycol) or kinetic hydrate inhibitors or operating outside the hydratestability zone by insulating the pipeline and/or active heating. These techniques are not always economical and in some cases are not practical for deepwater operations, long tiebacks, or aging reservoirs with high water cuts. The industry needs new and novel flow-assurance techniques to address these challenging conditions. The approach presented in this paper is a wet cold-flow-based method in which gas-hydrate management rather than...