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Jitendra Sangwai
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Jitendra Sangwai
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Jitendra Sangwai
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Sangwai, Jitendra S.
Sangwai, Jitendra
Sangwai, J. S.
Sangwai, Jitendra Shital
Sangwai, J.
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2 results
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- PublicationModeling of methane hydrate inhibition in the presence of green solvent for offshore oil and gas pipeline(01-01-2014)
;Avula, Venkata Ramana; In offshore gas transmission pipeline systems, typically gas and water are produced under high pressure and low temperature conditions causing the formation of gas hydrates blocking pipelines. Thermodynamic modeling is necessary to understand the phase stability of hydrate in the presence of green solvents namely, ionic liquids (ILs). In this work, the thermodynamic models are based on the computation of fugacity of hydrate phase using Van der Waals and Platteeuw solid solution theory combined with Peng - Robinson equation of state (PR-EoS) for fugacity of hydrate former in the gas phase and the computation of fugacity of aqueous water phase using activity coefficient models such as the non - random two - liquid (NRTL) model and Pitzer - Mayorga model. The model results are compared with available experimental data from open literature and observed to be in good agreement with the reported literature. Finally, the hydrate suppression temperature due to ILs on methane hydrate is calculated to know the inhibition effectiveness of IL on methane hydrate formation in offshore pipeline system. The overall accuracy of Pitzer-Mayorga model is found to be 5.8 % while NRTL model's accuracy was 6.3 % for various ILs and methane hydrate system. Model results further indicated that ILs with shorter alkyl chain length exhibit better inhibition effect. The model developed in this work shows potential application in the determination of hydrate phase stability using green solvent for offshore oil field applications. Copyright © 2014 by the International Society of Offshore and Polar Engineers (ISOPE). - PublicationAn improved model for the phase equilibrium of methane hydrate inhibition in the presence of ionic liquids(01-11-2014)
;Avula, Venkata Ramana; In this work, a thermodynamic model is developed and used to predict the phase stability conditions for methane hydrate-ionic liquid (IL)-water system. The hydrate phase is computed from modified van der Waals-Platteeuw model. The Peng-Robinson equation of state (PR-EoS) and developed activity model as a combination of Pitzer-Mayorga-Zavitsas-hydration model is used to evaluate the fugacities of gas and liquid phases, respectively. The hydrate phase stability prediction is also computed using the liquid phase activity predicted by NRTL and Pitzer-Mayogra models, separately, and is compared with the results predicted from the developed model. The model predictions are compared with experimental results on the phase stability of methane hydrate reported in open literatures for 21 ILs. The 21 ILs chosen from various ionic groups such as tetraalkylammonium, pyrrolidinium, imidazolium cationic family with various anion group such as halides (Cl, Br, I), sulphate (HSO4, ethylsulphate), tetrafluoroborate (BF4) and dicyanamide (DCA). The absolute average relative deviation in predicted pressure (AARD-P) with developed Pitzer-Mayorga-Zavitsas-hydration-model is improved to 1.60% and non-random two liquid (NRTL), Pitzer-Mayorga model showed 2.02% and 1.77% with 120 data points in the temperature range of 272.1-291.59K and pressure range of 2.48-20.67MPa. For 120 data points of phase stability conditions of 21 ILs, 39.2% of the predicted equilibrium pressures (47 data points) were within relative absolute deviation of 0.0-1.0%, 29.2% of the equilibrium pressures (35 data points) were within absolute deviation of 1.01-2.5%, 25.8% of data (31 data points) were within 2.51-7.5% which are mainly for data with low concentrations of ILs and only 5.8% of data (7 data points) showed relative absolute deviations above 7.5% which are observed mainly for data with high concentrations of ILs. Further, the model is used to calculate the inhibition effect of selected 21 ILs on methane hydrate formation.