Prospects Of Amino Acids And Ionic Liquids As Natural Gas Hydrate Inhibitors For Offshore Flow Assurance

Gas hydrates are ice-like compounds that are formed when small gas molecules get trapped within the water molecules at high pressure and low-temperature conditions. The formation of gas hydrates in the offshore subsea lines can lead to unwanted blockages and cause operations shut down. To prevent hydrate formation the chemical inhibitors like methanol and mono-ethylene glycol (MEG) are injected at the wellhead. But, the major drawbacks of using these inhibitors is that they are toxic, flammable, have environmental constraints and are required in bulk quantities ( > 30 wt%). In this work, for the first time, a comprehensive experimental study on the use of amino acids and ionic liquids as the natural gas hydrate inhibitors in the presence of synergent (PEO) have been conducted at wide process conditions (38-120 bars). The results show that the selected amino acids and ionic liquids exhibit dual functional behaviour by providing the temperature shift of around 1.5-2.3 oC and delaying the hydrate formation time from 0.5-1.5 hr. By the addition of synergent (PEO) with amino acids and ionic liquids, the hydrate formation time was delayed by 6 - 24 hr. The ionic liquids with shorter cationic alkyl chain and amino acids with higher solubility were observed to provide better hydrate inhibition effect. The inhibitors tend to show better hydrate inhibition effect at low pressures (40 bars) and their inhibition effect decreases as the pressure rises. At the same concentration (10 wt%), the ammonium-based ionic liquid [EA][Of] provided the inhibition effect similar to MEG and at the higher concentration (20 wt%) the amino acid glycine provided better hydrate inhibition effect than the MEG. This indicates that both amino acids and ionic liquids are potential gas hydrate inhibitors, but amino acids and their synergent mixtures are more suited for the large-scale usage due to their biological nature and widescale production. The effect of stirring on the hydrate crystal formation at different stirring rates (100-1400 RPM) was also investigated. It was found that a threshold limit exists for the stirring rate, above and below which no hydrate formation is likely to occur within the selected system. The maximum hydrate crystal formation occurs at moderate stirring rates and very high or low stirring rates are not suited for the stable hydrate crystal growth and formation. This work intends to provide industry with new generation of inhibitors that are cost effective, environmentally benign and offer strong hydrate inhibition strength. This work is beneficial for the industry and academic researchers as the required dosage of hydrate inhibitors has been reduced from 40 wt% to 5 wt%, which helps to reduce the overall CAPEX cost and reduce environmental concerns related to the disposal of the hydrate inhibitors. This work offers new arena of research in the area of hydrate inhibitors + synergents mixtures. These mixtures are effective and have potential to replace conventional hydrate inhibitors like methanol and ME

Protecting environment and assuring efficient energy transfer using ionic liquids

Gas hydrates are ice-like crystalline compounds that are formed when small gas molecules get trapped within the water molecules under high pressure and low-temperature conditions in oil and gas transmission lines. The formation of these hydrates is a major threat to oil and gas industry as they have a tendency to agglomerate and completely block the oil and gas transmission lines, which may lead to an explosion or cause unwanted operations shut down. Therefore, annually industry spends around 1 billion US dollars on hydrate prevention procedures which includes extensive use of chemical inhibitors. These chemical inhibitors are generally classified as thermodynamic hydrate inhibitors (THI) and kinetic hydrate inhibitors (KHI). The thermodynamic hydrate inhibitors function by shifting hydrate dissociation temperature to lower values and kinetic hydrate inhibitors function by delaying the hydrate formation time. The commercial THI like Methanol and Mono-ethylene glycol (MEG) perform well, but these inhibitors are required in large quantities (> 30 wt%) and cannot be easily disposed of into the environment. Therefore, there is a strong industrial need to design inhibitors that are environmentally friendly and are required in low dosage. Ionic liquids (ILs) well known as ionic fluids are a type of organic salts that have low melting points and tendency to stay in a liquid form at low or ambient temperature. Ionic liquids are extensively being used in different chemical processes due to their negligible vapor pressure and low viscosity. Recently, ionic liquid has been recognized as the dual functional inhibitors as they have the tendency to perform as kinetic hydrate inhibitor and thermodynamic hydrate inhibitor simultaneously. In this experimental-based work, the thermodynamic inhibition (TI) and kinetic inhibition (KI) effect of ionic liquids (ILs) 1-Methyl-1-Propyl-pyrrolidinium Chloride [PM-Py][Cl] and 1-Methyl-1-Propyl-pyrrolidinium Triflate [PM-Py][Triflate] have been investigated on a methane-rich gas mixture at different concentrations (1-5 wt%) and pressure ranges (40-120 bars). The effect of the addition of synergists with ionic liquids has been also studied and the experimental results have been compared with the commercial thermodynamic inhibitor methanol and literature data. All the experimental work has been conducted using PSL system tecknik rocking cell assembly (RC-5). The ionic liquid [PMPy][Cl] was found to be more effective than the IL [PMPy][Triflate].These experimental results, clearly show that the selected ionic liquids have a tendency to act as thermodynamic and kinetic inhibitors both simultaneously. In order to improve the kinetic inhibition effectiveness of the ionic liquids, the synergist polyethylene oxide (PEO) was added in equal ratio with the ionic liquids [PMPy][Triflate] and [PMPy][Cl]. The addition of PEO helped to enhance the kinetic inhibition effectiveness of these inhibitors significantly and delayed the hydrate induction time by 6 to 14 hours at the pressure range of 40-120 bars. A delay of 6 to 14 hours in hydrate induction time is highly beneficial for process operators as it allows them to take necessary action to avoid process disruptions as a result of hydrate formation. Acknowledgement This work was made possible by NPRP grant # 6-330-2-140 and GSRA # 2-1-0603-14012 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.qscienc

Gas hydrates inhibition via combined biomolecules and synergistic materials at wide process conditions

The motive of this research to present a systematic study in context of implementation of gas hydrate inhibitors that are obtained via naturally occurring amino acids (L-Alanine, Glycine, L-Histidine, L-Phenylalanine and L-Asparagine). These materials are tested for methane (CH4) hydrate inhibition purposes from both thermodynamically and kinetically perspectives at wide process conditions. In this presented work, all studied amino acids have been tested at both 1 wt % as low dosage inhibitors as well as at higher concentrations up to 5 wt %. Furthermore, Polyethylene-oxide (PEO) and Vinyl Caprolactum (VCap) were used at 1 wt % in studied aqueous solutions as synergetic compounds to enhance the inhibition performance for CH4 hydrate inhibition. Gas hydrate experiments were carried out by using rocking cell apparatus, from which pressure, temperature equilibrium data were obtained at recorded time and these data were translated into inhibitor performance evaluation from both thermodynamics and kinetic inhibition perspectives. This study includes the discussions of the effect of solubility limitation of studied amino acids, the effect of inhibitor concentration effect on the thermodynamic shift of the hydrate equilibrium curve, the role of side chain in amino acids in kinetic hydrate inhibition, the hydrophobic interactions of alkyl chain in water for synergistic point of view. The results showed that the suitability of amino acids combined with synergistic materials for high kinetic inhibition performance, which provided an additional time shift up to 35 h in hydrate formation at moderate process conditions up to 55 bars, specifically when L-Alanine was used.This work was made possible by NPRP grant # 6-330-2-140 and GSRA # 2-1-0603-14012 from the Qatar National Research Fund (a member of Qatar Foundation). The statements made herein are solely the responsibility of the authors.Scopu

Decline in subarachnoid haemorrhage volumes associated with the first wave of the COVID-19 pandemic

BACKGROUND: During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study\u27s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines. METHODS: We conducted a cross-sectional, retrospective, observational study across 6 continents, 37 countries and 140 comprehensive stroke centres. Patients with the diagnosis of SAH, aneurysmal SAH, ruptured aneurysm coiling interventions and COVID-19 were identified by prospective aneurysm databases or by International Classification of Diseases, 10th Revision, codes. The 3-month cumulative volume, monthly volumes for SAH hospitalisations and ruptured aneurysm coiling procedures were compared for the period before (1 year and immediately before) and during the pandemic, defined as 1 March-31 May 2020. The prior 1-year control period (1 March-31 May 2019) was obtained to account for seasonal variation. FINDINGS: There was a significant decline in SAH hospitalisations, with 2044 admissions in the 3 months immediately before and 1585 admissions during the pandemic, representing a relative decline of 22.5% (95% CI -24.3% to -20.7%, p\u3c0.0001). Embolisation of ruptured aneurysms declined with 1170-1035 procedures, respectively, representing an 11.5% (95%CI -13.5% to -9.8%, p=0.002) relative drop. Subgroup analysis was noted for aneurysmal SAH hospitalisation decline from 834 to 626 hospitalisations, a 24.9% relative decline (95% CI -28.0% to -22.1%, p\u3c0.0001). A relative increase in ruptured aneurysm coiling was noted in low coiling volume hospitals of 41.1% (95% CI 32.3% to 50.6%, p=0.008) despite a decrease in SAH admissions in this tertile. INTERPRETATION: There was a relative decrease in the volume of SAH hospitalisations, aneurysmal SAH hospitalisations and ruptured aneurysm embolisations during the COVID-19 pandemic. These findings in SAH are consistent with a decrease in other emergencies, such as stroke and myocardial infarction

Gas Hydrate Prevention and Flow Assurance by Using Mixtures of Ionic Liquids and Synergent Compounds: Combined Kinetics and Thermodynamic Approach

The thermodynamic and kinetic hydrates inhibition effects of addition of synergents poly(ethylene oxide) (PEO) and vinyl caprolactum (VCAP) with ionic liquids 1-methyl-1-propylpyrrolidinium chloride [PMPy][Cl] and 1-methyl-1-propylpyrrolidinium triflate [PMPy][triflate] were studied on a synthetic quaternary gas mixture (methane, C1 = 84.20%; ethane, C2 = 9.90%; n-hexane, C6+ = 0.015%; CO2 = 2.46%; N2 = 2.19%). The results show that the addition of synergents with ionic liquids helps to improve their thermodynamic and kinetic hydrate inhibition effectiveness simultaneously. 2016 American Chemical Society.Scopu

Effect of drill pipe orbital motion on non-Newtonian fluid flow in an eccentric wellbore: a study with computational fluid dynamics

10.1007/s13202-021-01403-yJournal of Petroleum Exploration and Production Technolog

CO2 Gas hydrate for carbon capture and storage applications – Part 1

Gas hydrates are solid crystalline compounds formed by water and gas molecules through molecular interactions, typically at low temperatures and high pressures. While gas hydrates are generally known as flow assurance challenges for the oil and gas industries (e.g., pipeline blockages), numerous studies have shown the potential application of gas hydrate in carbon capture and storage (CCS). Due to the more thermodynamic stability of CO2 hydrate compared to other industrial emission gas components like nitrogen, CO2 hydrates have emerged as a viable mechanism for CO2 capture. Moreover, a large volume of CO2 can be stored securely in the stable structure of gas hydrates, providing an additional benefit for CO2 storage in geological formations. Thus, gas hydrates can be suggested as a technology for mitigating CO2 emissions. Notwithstanding the CO2 hydrate advantages in CCS, they may also present some challenges, particularly in terms of flow assurance. For example, CO2 hydrate formation during CO2 transportation can cause a serious pipeline blockage. Therefore, the fundamental understanding of gas hydrates is crucial for CCS. In the first part of this review, the principle on gas hydrates (especially CO2 hydrates) and CO2 hydrate-based carbon capture are discussed

CO2 Gas hydrate for carbon capture and storage applications – Part 1

Gas hydrates are solid crystalline compounds formed by water and gas molecules through molecular interactions, typically at low temperatures and high pressures. While gas hydrates are generally known as flow assurance challenges for the oil and gas industries (e.g., pipeline blockages), numerous studies have shown the potential application of gas hydrate in carbon capture and storage (CCS). Due to the more thermodynamic stability of CO2 hydrate compared to other industrial emission gas components like nitrogen, CO2 hydrates have emerged as a viable mechanism for CO2 capture. Moreover, a large volume of CO2 can be stored securely in the stable structure of gas hydrates, providing an additional benefit for CO2 storage in geological formations. Thus, gas hydrates can be suggested as a technology for mitigating CO2 emissions. Notwithstanding the CO2 hydrate advantages in CCS, they may also present some challenges, particularly in terms of flow assurance. For example, CO2 hydrate formation during CO2 transportation can cause a serious pipeline blockage. Therefore, the fundamental understanding of gas hydrates is crucial for CCS. In the first part of this review, the principle on gas hydrates (especially CO2 hydrates) and CO2 hydrate-based carbon capture are discussed

CO₂ gas hydrate for carbon capture and storage applications – Part 2

CO2 hydrate offers some substantial applications for Carbon Capture and Storage (CCS). While CO2 hydrate chemistry and CO2 capture are reviewed in part 1 of this review, CO2 transportation and storage are discussed in this part. Basically, CO2 transportation is required between CO2 capture plants and CO2 sequestration sites. It is imperative to acknowledge that most strategies for achieving deep decarbonization are linked to the expansion of the current transport infrastructure. When dealing with substantial distances between CO2 capture plants and CO2 sequestration sites, the expenses associated with CO2 transportation can surpass the capture process itself. Therefore, despite the benefits of CO2 hydrates in CCS, challenges, such as flow assurance issues, may arise. For example, CO2 hydrate formation can lead to pipeline blockages, emphasizing the need for CO2 gas hydrate flow assurance study as discussed in this part.Additionally, site selection for CO2 storage requires careful consideration. Geological storage, whether in hydrate form or through the injection of CO2 or high-CO2 content mixtures, offers potential advantages, such as long-term storage and self-sealing capabilities. However, there are some challenges like CO2 hydrate processes in porous media, injectivity, flow behaviour in hydrate reservoirs, mechanical behaviour, etc., which are discussed in this review