Monoethylene Glycol Solutions Research Articles

Evaluating the impact of sodium chloride and iron carbonate ions on gas hydrate formation in Monoethylene Glycol‐enhanced aqueous solutions

AbstractThe management and prevention of hydrates are crucial for the gas industry. This study delves into the intricate challenges associated with gas hydrate formation, with a specific focus on investigating the impact of corrosion by‐products on prevention strategies. Employing a distinctive methodology, the sapphire pressure–volume temperature (PVT) cell was utilized. Experimental tests were conducted using sodium chloride (NaCl) concentrations of 1% and 3% to simulate brine solution levels at the wellhead, incorporating 3% filtrate and unfiltered iron carbonate (FeCO3) as corrosion products associated with the production process. The 1% and 3% salt concentrations were chosen to encompass a broad range of temperature depressions, reflecting common industry standards for simulating realistic environmental conditions. PVT cell test conditions ranged from 80 to 200 bar, with increments of 40 bar. The experiments investigate the effects of common pipeline salts on a monoethylene glycol (MEG)/water mixture in the presence of methane gas at typical industry high‐pressure conditions. The investigation uncovers that the introduction of salts to water, methane, and MEG solutions serves as a hydrate inhibitor, with inhibitory effects directly correlated to salt concentration. While generally hydrate growth inhibition is beneficial in natural gas pipelines, the findings indicate that elevated salt concentrations and lower pressure conditions contribute to the formation of larger hydrates, heightening the risk of surface adhesion and potentially introducing complications in piping equipment, despite the decreased temperature at which these hydrates form due to the inhibitory effects of the salts. In particular, the mixed condition of 3% NaCl and 3% FeCO3 (filtered) has the strongest effect. Examination of hydrate formation temperature and macroscopic observations suggests that the existence of substantial precipitates, as evidenced in the unfiltered FeCO3 sapphire cell experiment, may have the potential to enhance hydrate growth.

Kinetics and morphology of gas hydrate formation from MEG solution in under-inhibited systems

Natural gas hydrate blockages pose a major risk to deepwater oil and gas development. Thermodynamic under-inhibition is a cost-effective hydrate management strategy, but the impact of mono ethylene glycol (MEG) on hydrate formation kinetics and mass transfer at the gas–water interface requires further understanding for hydrate-related flow assurance. This study investigates the kinetics and morphology of hydrate growth from MEG solutions using in situ micro X-ray CT and a macro transparent reactor. MEG concentration emerged as the primary factor influencing hydrate growth morphology. Findings revealed that MEG alters the growth morphology of gas hydrates by inhibiting the formation of a hydrate film at the gas–liquid interface and inducing flocculent hydrate growth within the solution. MEG can also induce the formation of low-saturation hydrates, with no significant self-inhibition observed at concentrations below 20 %. Over time, a dense hydrate shell tended to form on the surface of the hydrate lump, increasing the risk of blockage. Additionally, it was observed that subcooling also affects the hydrate growth morphology; higher subcooling accelerates the hydrate growth rate and increases the density of the formed hydrate. This research explored the mechanisms underlying hydrate formation in under-inhibited systems, aiming to extend the safe operational boundary for oil and gas transportation and provide theoretical support for deepwater hydrate management.

Influence of magnetic field exposure on methane hydrate

Gas hydrate mitigation is considered a painstaking process in the oil and gas industry. Chemically, mono ethylene glycol (MEG) is used to control the gas hydrate formation. However, gas hydrate formation can also be affected by an external magnetic field under certain conditions such as subsea production equipment that can generate a magnetic field. This magnetic field could influence the physical behaviour of the gas hydrate conditions of the transported fluid within the subsea production pipelines. The objectives of this research were to assess the effects of exposing water and 20 wt % MEG solution to the magnetic field of 13,499 Gauss, neodymium magnet, on methane hydrate formation in correlation with field exposure time and memory effects. This study determined that, for the water solution, there was a proportional, incremental trend between the magnetic field exposure time and its memory effect for exposures of 172, 258 and 387 h. The dissociation temperatures of the magnetized solutions were raised and had different hydrate developments. However, no effects were found on the 20 wt % MEG solution. It has been inferred from this outcome that the addition of MEG impacted on the water molecules numbers within the hydration shell. The application of the potential magnetic effect as a control method can provide in-depth and better understanding of the hydrate behaviour and mechanism at subsea conditions.

Effect of electrolyte solubility and column inclination on the performance of monoethylene glycol regeneration process

AbstractIn this study, the solubilities of potassium‐chloride (KCl) in aqueous monoethylene glycol (MEG) solution and the vapour pressure of aqueous MEG solution containing KCl were investigated. A thermodynamic model was modified based on the data obtained to predict the solubilities of KCl, which was then applied to optimize the MEG regeneration process that is widely used in offshore gas fields. The solubility of KCl in the aqueous MEG solution decreased with an increase in MEG concentration and a decrease in temperature. The presence of KCl in aqueous MEG solution decreased the vapour pressure, thus increasing the boiling temperature at the corresponding pressure. A thermodynamic model based on the electrolyte non‐random two‐liquid (NRTL) coupled with the Redlich–Kwong (RK) equation of state was employed by modifying the binary interaction parameters using the experimental data. The modified model predicted the solubilities of KCl and the vapour pressure of aqueous MEG solutions, which were in good agreement with the experimental data. Moreover, the distillation column in pilot‐scale MEG regeneration was inclined to simulate the movement of the offshore platform, showing decreasing MEG concentration, possibly due to the distribution issues inside the column.

An experimental study of calcium carbonate precipitation with hydrate inhibitor in MEG recovery unit

Monoethylene glycol (MEG) is a thermodynamic inhibitor of gas hydrate formation used in the oil industry. Regeneration of MEG for reinjection in wells is necessary to minimize operating costs due to the large amounts of this additive employed. However, this scenario favors the precipitation of inorganic salts from the produced water, mainly calcium carbonate (CaCO3). This work is devoted to evaluating the CaCO3 precipitation in water + MEG mixtures (0–50 vol.% MEG) at different concentrations of reacting salts (0.01–0.1 mol L−1) and temperatures (25–60 °C). The focused beam reflectance measurement (FBRM) technique was used for inline monitoring of chord length and CaCO3 particles distribution in the suspension for 60 min. Optical microscopy was used to understand the particle precipitation phenomena. FBRM results show that the size distribution and the number of CaCO3 particles in the aqueous solution vary with time, temperature, reacting salts, and MEG concentrations. The higher the salt concentration, the larger both the size and number of precipitated chords. Temperature expressively affects salt precipitation. For a given concentration of MEG, the enhancement in temperature favors the increase in the amount and size of chords. Specifically, for 10% v/v of MEG solutions, the particle size increases from 8.0 ± 0.5 μm (at 25 °C) to 20.4 ± 2.1 μm (at 60 °C). Additionally, at 30% v/v of MEG in the solution, the particle size increases from 5.4 ± 0.4 μm (at 25 °C) to 15.5 ± 0.2 μm (at 60 °C). These outcomes are related to the reduction in CaCO3 solubility and the improvement in MEG viscosity with temperature. Optical microscopy measurements corroborate the FBRM data, thus demonstrating the influence of the parameters MEG concentration, ionic concentration, and temperature have on the number and size of precipitated carbonate crystals.

Monoethylene glycol reclamation based on chemical precipitation process

The key step in reclamation of monoethylene glycol (MEG) is chloride removal from the rich MEG solution containing high Cl concentration. Chloride removal from MEG reclamation operation has been investigated in this wok through the chemical precipitation of insoluble Friedel's salt, created by the addition of calcium and aluminum compounds. Response surface methodology has been used to design experiments and optimize the effect of independent variables. The selected ranges of various factors were: initial concentration of chloride (1500–4500 mg/l), molar ratio of Al: Cl (0.5–3), molar ratio of Ca: Cl (1–6), Temperature (25–80 °C), and wt.% of MEG (30–70). It was found that at higher starting Cl concentrations, the reaction for forming Friedel's salt is superior to other reactions. The efficiency of multi-stage Cl removal has also been investigated. It was found that, under assumed operating conditions, a 70% removal efficiency at each step and a 97% chloride removal can be achieved by the end of stage 3.

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

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.

Insights into kinetic inhibition effects of MEG, PVP, and L-tyrosine aqueous solutions on natural gas hydrate formation

It is necessary to understand all the prerequisites, which result in gas hydrate formation for safe design and control of a variety of processes in petroleum industry. Thermodynamic hydrate inhibitors (THIs) are normally used to preclude gas hydrate formation by shifting hydrate stability region to lower temperatures and higher pressures. Sometimes, it is difficult to avoid hydrate formation and hydrates will form anyway. In this situation, kinetic hydrate inhibitors (KHIs) can be used to postpone formation of gas hydrates by retarding hydrate nucleation and growth rate. In this study, two kinetic parameters including natural gas hydrate formation induction time and the rate of gas consumption were experimentally investigated in the presence of monoethylene glycol (MEG), L-tyrosine, and polyvinylpyrrolidone (PVP) at various concentrations in aqueous solutions. Since hydrate formation is a stochastic phenomenon, the repeatability of each kinetic parameter was evaluated several times and the average values for the hydrate formation induction times and the rates of gas consumption are reported. The results indicate that from the view point of hydrate formation induction time, 2 wt% PVP and 20 wt% MEG aqueous solutions have the highest values and are the best choices. It is also interpreted from the results that from the view point of the rate of gas consumption, 20 wt% MEG aqueous solution yields the lowest value and is the best choice. Finally, it is concluded that the combination of PVP and MEG in an aqueous solution has a simultaneous synergistic impact on natural gas hydrate formation induction time and the rate of gas consumption. Furthermore, a semi-empirical model based on chemical kinetic theory is applied to evaluate the hydrate formation induction time data. A good agreement between the experimental and calculated hydrate formation induction time data is observed.

Effect of Mono Ethylene Glycol Solution on Mechanical Behavior of a Clay Soil

Abstract This article presents the results of an investigation into the behavior of a clay soil contaminated with mono ethylene glycol (MEG) through a program of experimental tests. Soil specimens were prepared with water or different concentrations (10, 25 and 40 %) of MEG by the slurry method. One-dimensional consolidation and consolidated undrained (CU) triaxial tests were performed on the specimens. The results of the consolidation tests showed that the preconsolidation pressure is increased and the value of λ (slope of normal consolidation line) is decreased with an increase in the concentration of MEG. In addition, the results of the CU triaxial tests indicated that the friction angles (in term of total and effective stresses) are greater for the MEG solution than for water as pore fluid, and their values are increased with an increase in the concentration of the MEG solution. It was also shown that Roscoe surface exists for contaminated soil in q, p′, v space, and its position in this space is dependent on the concentration of pore fluid.

Oxygen scavenging performance of carboxylic acids formed during the degradation of monoethylene glycol regeneration products

Previous studies have demonstrated that formic and glycolic acids could scavenge oxygen from aqueous solutions via complex radical mechanisms similar to that of erythorbic acid. Therefore, it is important to study the feasibility of using these common thermal degradation products obtained from the regeneration of monoethylene glycol (MEG). By replacing commercially used oxygen scavengers, such as sulfites, with these organic acids, the toxicity and subsequent environmental impact of oil and gas products could be easily reduced. Furthermore, these organic acids are rapid oxygen scavengers at low concentration, and they could be cost-effective; in addition, the chemical inventory could be reduced and project costs could be further optimized. The experimental results confirmed the potential of formic and glycolic acids to be used as oxygen scavengers downstream of the MEG regeneration process in the presence of manganese (II) ions as catalyst. Of the two commercial aqueous industrial oxygen scavengers tested, diethylhydroxylamine was an extremely rapid oxygen scavenger in salty aged lean MEG solutions under alkaline conditions, whereas methyl ethyl ketoxime exhibited extremely poor performance under similar conditions; therefore, it was ruled out as potential oxygen scavenger.

Performance of erythorbic acid as an oxygen scavenger in salted fresh and degraded monoethylene glycol under a magnetic memory effect

AbstractStudies show that erythorbic acid is an effective oxygen scavenger in the food industry, thereby suggesting its potential for use in monoethylene glycol (MEG) regeneration systems. However, its performance under magnetic memory effects has not been studied. This study was conducted with 85‐vol.% fresh MEG (F‐MEG) and degraded MEG (D‐MEG) solutions, preadjusted to pH 9.0 and pretreated with a magnetic field (MF). Two oxygen concentrations, ~7,000 and ~1,000 ppb, high‐salinity concentrations (HF‐MEG and HD‐MEG), and organic acids were also employed. The applied MF strength, generated by a cylindrical permanent magnet, was ~0.65 T.The erythorbic acid scavenging performance was enhanced upon exposure of the HF‐MEG solutions to an MF. Conversely, the magnetized salt‐free D‐MEG solutions displayed a lower scavenging performance than the nonmagnetized solutions: Oxygen removal was more effective in the D‐MEG solutions than in the HF‐MEG solutions, regardless of magnetization, due to formic acid formation during the thermal oxidization process. Furthermore, the magnetized HF‐MEG solutions exhibited a progressive increase in pH over time, whereas the nonexposed and D‐MEG solutions presented different responses. Iron ions, acting as metal catalysts, also affected the oxygen scavenging performance in the D‐MEG tests. The results suggest that the erythorbic acid scavenging performance can be improved by promoting the forward reaction using an MF. In addition, in the presence of erythorbic acid and only under specific conditions, formic acid can be used as secondary oxygen scavenger in oil and gas industry. Stable alkaline conditions are also necessary to achieve better scavenging performance. These results can be attributed to the influence of the MF on the spin state mechanism, given that the electron spin dynamics are affected by the Zeeman effect.

Effect of wettability on particle settlement behavior within Mono-Ethylene Glycol regeneration pre-treatment systems

This study was undertaken to diagnose routine settling problems within a third-party oil and gas companies’ Mono-Ethylene Glycol (MEG) regeneration system. Two primary issues were identified including; a) low particle size (<40 μm) resulting in poor settlement within high viscosity MEG solution and b) exposure to hydrocarbon condensate causing modification of particle surface properties through oil-wetting of the particle surface. Analysis of oil-wetted quartz and iron carbonate (FeCO₃) settlement behavior found a greater tendency to remain suspended in the solution and be removed in the rich MEG effluent stream or to strongly float and accumulate at the liquid-vapor interface in comparison to naturally water-wetted particles.As such, exposure of particles including quartz and FeCO₃ to the condensate phase within natural gas transportation pipelines may ultimately cause poor settlement of suspended particles downstream within MEG regeneration systems, leading to increase filtration requirements. The effect of oil-wetting on particle settlement was successfully managed through application of a cationic surfactants, including cetrimonium bromide (CTAB), to transition the initially oil-wetted surface to water-wetted. Cationic surfactants were found to be most suitable due to the negative surface charge of mineral particles at pH levels typical of MEG regeneration system pre-treatment systems (pH > 8).

Operational study of a monoethylene glycol (MEG) desalination pilot plant. Part I: Development of a new method for the estimation of MEG content in the presence of NaCl solid particles

Conductivity measurements at different temperatureswere undertaken to investigate the variation of conductivity as a function of sodium chloride solid particle concentrations in sodium chloride-saturated aqueous monoethylene glycol (MEG) solutions. A methodology has been developed that is capable of quantifying the relationship between the conductivity measurement, sodium chloride particle concentration, temperature, and MEG concentration in the brine-saturated aqueous solution. The results indicate that the conductivity decreases exponentially as the solid sodium chloride particle concentration increases from 0 to 30 wt%, whereas in the absence solid particles, the conductivity of sodium chloride-saturated aqueous MEG solutions is a polynomial function of temperature and MEG concentration. It is demonstrated that a single, universal empirical model can be developed to quantify the relationship between the conductivity and relevant process parameters across the whole experimental range. The methodology can be readily adopted for in situ monitoring of solid salt particle concentration and estimation of MEG loss in a typical industrial MEG reclamation process, leading to the establishment of more effective process control and operation strategies.

Absorption kinetics of mercury (II) chloride into mono-ethylene glycol (MEG) solution

Different mercury species have been found in the oil and gas reservoirs. Dynamic absorption of mercury (II) chloride (HgCl2) into solutions of mono-ethylene glycol (MEG) is reported in this work. It was observed that absorption of HgCl2 into MEG solutions was comparable to the absorption in pure water and the effect on MEG was not seen for MEG concentrations of 2–30 v/v%. The absorption flux was mainly affected by the absorption temperature and the concentration of HgCl2 in the gas phase. Utilisation of several mercury analysis techniques such as flow injection mercury spectroscopy (FIMS), inductively couple plasma-mass spectroscopy (ICP-MS), Fourier-transform infrared spectroscopy (FTIR) and Raman spectroscopy show that no interactions between HgCl2 and MEG were detected for the test parameters studied. The findings from this work helps to improve the knowledge on the behaviour of HgCl2 within natural gas processing facilities, especially during transportation in pipelines and the MEG regeneration process.

Degradation and hydrate phase equilibria measurement methods of monoethylene glycol

Monoethylene glycol (MEG), a common chemical used for the inhibition of gas hydrate formation may undergo degradation in the regeneration/reclamation process. Limited research exists on the effect of degradation of MEG on hydrate formation, production facilities and equipment especially in the presence of other chemical additives. The proposed method allows for streamlining the process of preparing, degrading and analysis of MEG solutions for hydrate testing and degradation products.•Procedure to prepare accurate MEG solutions avoiding oxidative degradation of MEG (i.e., controlling oxygen ingress).•Two methods are suggested to mimic field-like degradation of MEG solutions (i.e., degradation by reclamation and autoclave).•Adoption of the isochoric hydrate testing method while using a high pressure cell with the aid of a computer script to accurately evaluate hydrate phase equilibria conditions.

The influence of magnetic fields on calcium carbonate scale formation within monoethylene glycol solutions at regeneration conditions

One of the most discussed topics related to the effects of external magnetic fields (MF) on aqueous solutions is the influence on the scale formation of calcium carbonate (CaCO3). However, the extent of the effect of these forces on the scale formation in the non-aqueous solutions has not been investigated so far. So MFs will be applied to non-aqueous mixtures to find out the behavior of scale formation. This study presents the results of inorganic scale formation within MEG solutions containing Ca2+ and HCO3− ions, which has been investigated using both static and dynamic scale loop (DSL) evaluation techniques. Furthermore, the influence of MFs on scale formation using the dynamic technique has also been studied. Results were generated using brine/MEG solutions exposed to an external MF produced by a 0.65 T Neodymium magnet for 2.5 s. The degree of scale formation was examined by measuring the pressure build-up across a capillary coil as scale was developed. Moreover, differences in CaCO3 morphologies were evaluated for the exposed and blank trials via the DSL technique and compared with the results obtained from the static scale evaluation method.The results of this research have demonstrated that the short exposure (2.5 s) to a powerful MF can significantly reduce scale-formation in the rich MEG solutions within the capillary coil. This is due to the alteration of the proton spin inversion in the field of diamagnetic salts. Furthermore, a significant difference in CaCO3 morphology was observed for the scale formed during dynamic and static conditions. The generating results help to reduce the use of chemical scale inhibitors with MEG solution during the gas hydrate treatments, especially when the concentration of MEG in formation water is low and scale formation is more likely to occur.

Morphology Study on the Effect of Thermodynamic Inhibitors during Methane Hydrate Formation in the Presence of NaCl

In this study, we investigate the morphology of methane hydrate formation and growth in the presence of well-known thermodynamic inhibitors, monoethylene glycol (MEG) and methanol (MeOH) in a quiescent system. Morphology changes observed during the growth of methane hydrate while employing 5 wt % MEG and MeOH solutions in the presence and absence of NaCl are presented. When 5 wt % of MEG or MeOH was present in an aqueous solution individually, hydrate grew predominantly within the bulk solution featuring a “ridge”-shaped formation above the interface. In the presence of 3.5 wt % NaCl, an enhanced inhibition was observed for methane hydrates formed from 5 wt % MEG solution with limited hydrate growth in the bulk solution and above the gas-liquid interface. In contrast, 5 wt % MeOH solution in the presence of 3.5 wt % NaCl resulted in an increased hydrate growth in bulk (compared to the system without NaCl) and on the reactor wall above the gas–liquid interface, implying a weak promotion rather than the inh...

The behavior of mercury in water, alcohols, monoethylene glycol and triethylene glycol II. Elemental mercury solubility in alcohols, ethers and acetone; gas plant mercury distribution; and speciation in monoethylene glycol solution

This short communication provides elemental mercury equilibrium solubilities in 1-hexanol, 1-decanol, 2-propanone (acetone), 2-[(propan-2-yl)oxy]propane (diisopropyl ether), and 1-butoxybutane (dibutyl ether) over the approximate temperature range, 255–333 K. Exponential expressions of the solubility are presented in the form: Solubility (ng/g) = Aext, where t is in ⁰C. In a low temperature separator at a gas field, mercury partitioning has been modelled. At separator temperature and pressure conditions of 263–267 K and 2600–3100 kPa, ∼94 wt% of the mercury is calculated to report to the vapor phase, whilst ∼3 wt% each reports to the condensate and aqueous phases. The aqueous phase consists of H2O-rich monoethylene glycol (36 wt% MEG) used to inhibit gas hydrate formation. Sampling and analysis show that the H2O-rich and H2O-lean MEG streams contain predominantly particulate mercury. The use of this technical information is critical to planning for mercury removal, decontamination and waste minimization.

Acid Dissociation Constant (pKa) of Common Monoethylene Glycol (MEG) Regeneration Organic Acids and Methyldiethanolamine at Varying MEG Concentration, Temperature, and Ionic Strength

The acid dissociation constants (pKa) of four organic acids (formic, acetic, propanoic, and butanoic) commonly found in monoethylene glycol (MEG) regeneration systems and methyldiethanolamine (MDEA) were measured via potentiometric titration. Dissociation constants were measured within varying concentration of MEG solution (0, 30, 40, 50, 60, 70, and 80 wt %) and at varying temperature (25, 30, 40, 50, 60, 70, and 80 °C). Thermodynamic properties of the dissociation process including Gibbs free energy (ΔG° kJ mol–1), standard enthalpy (ΔH° kJ mol–1), and entropy (ΔS° kJ mol–1 K–1) were calculated at 25 °C using the van’t Hoff equation. Comparison of the reported experimental pKa values and calculated thermodynamic properties in aqueous solution to the literature demonstrated good agreement. Two models have been proposed to calculate the pKa of acetic acid and MDEA within MEG solutions of varying concentration, temperature, and ionic strength. The proposed models have an average error of 0.413% and 0.265% ...

Effect of Dissolved Oxygen, Sodium Bisulfite, and Oxygen Scavengers on Methane Hydrate Inhibition

Numerous chemical additives are added to monoethylene glycol (MEG) injection streams to maintain and protect assets as well as to ensure steady production of hydrocarbons. Oxygen scavengers are injected for the purpose of lowering dissolved oxygen to levels that do not pose the risk of corrosion. In this study, the effect of dissolved oxygen and some oxygen scavengers on gas hydrate inhibition was investigated. Results reveal that high levels of dissolved oxygen may promote the formation of hydrates due to the reaction of dissolved oxygen with impurity components such as iron carbonate that may exist in the MEG solution, thus decreasing overall MEG quality. Sodium bisulfite had negligible effect on hydrate inhibition at low concentrations but showed greater inhibition performance at higher concentrations due to the electrostatic attraction between ions and water molecules. A proprietary oxygen scavenger showed hydrate promotion effect, which suggests that proprietary chemical additives should undergo exte...