Thermodynamic Modeling Of Electrolytic Solutions of Ionic Liquids for Gas Hydrates Inhibition Applications

Abstract

The formation of hydrates in oil and gas transmission pipelines can cause blockage inside them and disrupt the normal flow. It may cause safety problems along with economic loss. To avoid these problems, it is necessary to have knowledge about gas hydrate formation. In this regard, hydrate liquid vapor equilibrium (HLVE) modeling can prove to be of significance as it predicts the phenomenon accurately. Dickens and Quinby-Hunt model is used to predict HLVE points. The experimental data has been obtained from open literature concerning inhibition of gas hydrates. The electrolytic binary solution mixtures of ionic liquids and quaternary ammonium salts (QAS) with commercial hydrate inhibitors have been taken into consideration. Methanol and mono ethylene glycol (MEG) are commercially used inhibitors. The gases forming hydrates include CO2, CH4 and mixed gas (CO2/CH4/N2). The experimental results are compared with the results obtained through modeling. The results show the applicability of the model as in case of QAS+MEG solution mixture hydrates with CO2, it shows a good fit. The HLVE findings by model for CH4 hydrates with EMIM-Cl+MEG solution mixture showed an average absolute error of less than 1% which is acceptable. The binary solution mixtures of NaCl+MEG, NaCl+MeOH and CaCl2+MeOH with tertiary gas mixture rich in CO2 were also modeled to find and compare the HLVE points from literature. It is found that the selected model is more suitable to be used in low pressure conditions and at high pressure, average absolute error (AAE) between experimental and modeling values is also high. It shows the suitability of the model and it can be further used in case of ionic compounds to predict hydrate inhibition behavior.

Effect of Hydrogen Bonding Energy and Freezing Point Depression of Quaternary Ammonium Salts on the Thermodynamic Gas Hydrate Inhibition

“…The values of both dissociation temperatures were attained at the same pressure, and “ n ” refers to the number of pressure points considered. The average suppression temperature ( ) was extracted from our earlier reported HLVE data for CH 4 , and CO 2 , gas hydrate systems in the presence and absence of QAS solutions.…”

Application of Gaussian Process Regression (GPR) in Gas Hydrate Mitigation

“…Gas hydrate was developed in a pipeline where many efforts have been made in the 1930s to understand the clathrate hydrate in terms of structure, compound, balance state and way of managing them due to it poses issues such as plugging of pipelines to produce offshore oil and gas, pressure drop and corrosion plants [1][2][3][4][5][6][7]. When sufficient water molecules in the form of oil and hydrocarbon vapour crystallize under intermittent flow conditions, gas hydrate or known as clathrate hydrate occurs.…”

“…When sufficient water molecules in the form of oil and hydrocarbon vapour crystallize under intermittent flow conditions, gas hydrate or known as clathrate hydrate occurs. It is an ice-like, non-stochiometric crystalline mixture made up of a water cage frame dominated by gas molecules like methane, CH4, ethane, C2H5, and carbon dioxide, CO2, that forms solid particles that takes place under high pressure and low temperature conditions [3][4][5][6]. Gas hydrates are produced in the petroleum and natural gas industries' output, refining and transmission facilities [8][9][10].…”

“…Besides that, there are 136 water molecules for a unit cell of structure II and enclosed 24 cavities, including 16 smalls and 8 wide ones [14]. It is therefore important to resolve the problem of gas hydrate development by introducing appropriate preventive and predictive strategies [3,16]. There are many risk control techniques that have been used,'such as the use of thermodynamic hydrate inhibitor (THI) inhibitors and low-dose hydrate inhibitor (LDHI) inhibitors.…”