scholarly journals Influence of Gas Supply Changes on the Formation Process of Complex Mixed Gas Hydrates

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 3039
Author(s):  
Mengdi Pan ◽  
Judith M. Schicks
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Formation Process ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Experimental Investigations ◽  
Gas Composition ◽  
Mixed Gas ◽  
Hydrate Phase ◽  
Gas Supply

Natural gas hydrate occurrences contain predominantly methane; however, there are increasing reports of complex mixed gas hydrates and coexisting hydrate phases. Changes in the feed gas composition due to the preferred incorporation of certain components into the hydrate phase and an inadequate gas supply is often assumed to be the cause of coexisting hydrate phases. This could also be the case for the gas hydrate system in Qilian Mountain permafrost (QMP), which is mainly controlled by pores and fractures with complex gas compositions. This study is dedicated to the experimental investigations on the formation process of mixed gas hydrates based on the reservoir conditions in QMP. Hydrates were synthesized from water and a gas mixture under different gas supply conditions to study the effects on the hydrate formation process. In situ Raman spectroscopic measurements and microscopic observations were applied to record changes in both gas and hydrate phase over the whole formation process. The results demonstrated the effects of gas flow on the composition of the resulting hydrate phase, indicating a competitive enclathration of guest molecules into the hydrate lattice depending on their properties. Another observation was that despite significant changes in the gas composition, no coexisting hydrate phases were formed.

Investigating the dynamics of gas hydrates in a gas dominant flow loop

2011 ◽  
Vol 51 (2) ◽  
pp. 734
Author(s):  
Yutaek Seo ◽  
Mauricio Di Lorenzo ◽  
Gerardo Sanchez-Soto
Keyword(s):  
Steady State ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Gas Flow ◽  
Transient Flow ◽  
Hydrate Formation ◽  
Hydrodynamic Condition ◽  
Gas Pipelines ◽  
Flow Loop ◽  
Offshore Pipelines

Offshore pipelines transporting hydrocarbon fluids have to be operated with great care to avoid problems related to flow assurance. Of these possible problems, gas hydrate is dreaded as it poses the greatest risk of plugging offshore pipelines and other production systems. As the search for oil and natural gas goes into deeper and colder offshore fields, the strategies for gas hydrate mitigation are evolving to the management of hydrate risks rather than costly complete prevention. CSIRO has been developing technologies that will facilitate the production of Australian deepwater gas reserves. One of its research programs is a recently commissioned investigation into the dynamic behaviour of gas hydrates in gas pipelines using a pilot-scale 1 inch and 40 m long flow loop. This work will provide experimental results conducted in the flow loop, designed to investigate the hydrate formation characteristics in steady state and transient flow. For a given hydrodynamic condition in steady state flow, the formation and subsequent agglomeration and deposition of hydrate particles appear to occur more severely as the subcooling condition is increasing. Transient flow during a shut-in and restart operation represents a more complex scenario for hydrate formation. Although hydrates develop as a thin layer on the surface of water during the shut-in period, most of the water is quickly converted to hydrate upon restart, forming hydrate laden slurry that is transported through the pipeline by the gas flow. These results could provide valuable insights into the present operation of offshore gas pipelines.

Insights into CO2 Capture by Flue Gas Hydrate Formation: Gas Composition Evolution in Systems Containing Gas Hydrates and Gas Mixtures at Stable Pressures

2018 ◽  
Vol 6 (5) ◽  
pp. 5732-5736 ◽  
Author(s):  
Aliakbar Hassanpouryouzband ◽  
Jinhai Yang ◽  
Bahman Tohidi ◽  
Evgeny Chuvilin ◽  
Vladimir Istomin ◽  
...  
Keyword(s):  
Co2 Capture ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Flue Gas ◽  
Hydrate Formation ◽  
Gas Mixtures ◽  
Gas Composition ◽  
Gas Hydrate Formation

scholarly journals Gas Hydrate Formation Phase Boundary Behaviour of Synthetic Natural Gas System of the Keta Basin of Ghana

2017 ◽  
Vol 10 (1) ◽  
pp. 64-72 ◽  
Author(s):  
Eric Broni-Bediako ◽  
Richard Amorin ◽  
Cornelius B. Bavoh
Keyword(s):  
Natural Gas ◽  
Phase Boundary ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Simulation Software ◽  
Gas Composition ◽  
Synthetic Natural Gas ◽  
Gas Hydrate Formation ◽  
Formation Phase

Background:Gas hydrates are considered as a major threat to the oil and gas flow assurance industry. At high pressure and low temperature conditions, gas hydrates form in pipelines and production facilities leading to pipeline blockages, high removal cost, environmental hazards and loss of lives. For a successful prevention of gas hydrate formation, predicting the hydrate formation phase boundary of hydrocarbon fluid composition becomes very necessary.Objective and Method:In this study, computer simulation software called PVTSim was used to predict hydrate formation phase boundary of synthetic natural gas composition of the Keta basin of Ghana at pressure and temperature ranges of 43.09 bar - 350 bar and 12.87 °C - 27.29 °C respectively. The effect of changes in natural gas composition (N2and H2S) and the presence of four commonly used thermodynamic gas hydrate inhibitors (methanol, ethanol, diethylene glycol and monoethylene glycol) on the hydrate formation phase boundary is also discussed. Prior to the study, the accuracy of PVTSim was validated with the hydrate formation phase data in literature.Results and Conclusion:Results suggested that the hydrate formation phase boundary decreased with increasing N2composition and increased with increasing H2S composition, suggesting that, the presence of H2S increases the threat of hydrate formation. However, a reduction in hydrate formation threat was observed in the presence of all four commonly used gas hydrate thermodynamic inhibitors with methanol demonstrating the highest inhibition effect.

Thermodynamic Modelling of Gas Hydrate Formation in the Presence of Inhibitors and the Consideration of their Effect

2014 ◽  
Vol 14 (1) ◽  
pp. 45
Author(s):  
Peyman Sabzi ◽  
Saheb Noroozi
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Low Temperatures ◽  
Hydrate Formation ◽  
Transportation Systems ◽  
Flow Lines ◽  
Main Approach ◽  
Efficient Inhibitor ◽  
System A ◽  
Gas Hydrate Formation

Gas hydrates formation is considered as one the greatest obstacles in gas transportation systems. Problems related to gas hydrate formation is more severe when dealing with transportation at low temperatures of deep water. In order to avoid formation of Gas hydrates, different inhibitors are used. Methanol is one of the most common and economically efficient inhibitor. Adding methanol to the flow lines, changes the thermodynamic equilibrium situation of the system. In order to predict these changes in thermodynamic behavior of the system, a series of modelings are performed using Matlab software in this paper. The main approach in this modeling is on the basis of Van der Waals and Plateau's thermodynamic approach. The obtained results of a system containing water, Methane and Methanol showed that hydrate formation pressure increases due to the increase of inhibitor amount in constant temperature and this increase is more in higher temperatures. Furthermore, these results were in harmony with the available empirical data.Keywords: Gas hydrates, thermodynamic inhibitor, modelling, pipeline blockage

scholarly journals Rapid Gas Hydrate Formation—Evaluation of Three Reactor Concepts and Feasibility Study

Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3615
Author(s):  
Florian Filarsky ◽  
Julian Wieser ◽  
Heyko Juergen Schultz
Keyword(s):  
Gas Hydrates ◽  
Gas Hydrate ◽  
Hydrate Formation ◽  
Synthetic Natural Gas ◽  
Operation Conditions ◽  
Gas Hydrate Formation ◽  
Gas Conditioning ◽  
And Storage ◽  
Economic Considerations ◽  
High Storage

Gas hydrates show great potential with regard to various technical applications, such as gas conditioning, separation and storage. Hence, there has been an increased interest in applied gas hydrate research worldwide in recent years. This paper describes the development of an energetically promising, highly attractive rapid gas hydrate production process that enables the instantaneous conditioning and storage of gases in the form of solid hydrates, as an alternative to costly established processes, such as, for example, cryogenic demethanization. In the first step of the investigations, three different reactor concepts for rapid hydrate formation were evaluated. It could be shown that coupled spraying with stirring provided the fastest hydrate formation and highest gas uptakes in the hydrate phase. In the second step, extensive experimental series were executed, using various different gas compositions on the example of synthetic natural gas mixtures containing methane, ethane and propane. Methane is eliminated from the gas phase and stored in gas hydrates. The experiments were conducted under moderate conditions (8 bar(g), 9–14 °C), using tetrahydrofuran as a thermodynamic promoter in a stoichiometric concentration of 5.56 mole%. High storage capacities, formation rates and separation efficiencies were achieved at moderate operation conditions supported by rough economic considerations, successfully showing the feasibility of this innovative concept. An adapted McCabe-Thiele diagram was created to approximately determine the necessary theoretical separation stage numbers for high purity gas separation requirements.

PROSPECTS FOR OBTAINING GAS MOTOR FUEL FROM BIOGAS OF ANAEROBIC DIGESTION OF AGRICULTURAL WASTE

2021 ◽  
Vol 3 (144) ◽  
pp. 22-31
Author(s):  
Viktor S. Grigor’yev ◽  
◽  
Il’ya V. Romanov
Keyword(s):  
Anaerobic Digestion ◽  
Gas Hydrates ◽  
Process Model ◽  
Organic Waste ◽  
Agricultural Waste ◽  
Motor Fuel ◽  
Hydrate Formation ◽  
Research Purpose ◽  
Industrial Complex ◽  
Mixed Gas

The ability of gas hydrates to concentrate gas into a solid chelate structure and the properties of self-preservation of gas hydrates at negative temperatures allows us to consider the possibility of developing a method for the utilization of biogas, environmentally safe storage and transportation of biomethane. (Research purpose) The research purpose is in substantiation the technological possibilities of obtaining synthetic mixed gas hydrates of biogas components, their storage and transportation based on the analysis of the existing regularities of the formation of gas hydrates in time, temperature and external pressure. (Materials and methods) The article presents the accumulated results of studies of the process of obtaining artificial hydrates of natural gas and methane- containing gas mixtures at various initial static pressures and temperatures. The object of research to substantiate the parameters of artificial creation of gas hydrates is biogas obtained during anaerobic thermophilic fermentation of organic waste at an existing experimental biogas plant. Mixed feed SK-8 with a humidity of 90-92 percent was used as an organic substrate of constant composition. The composition of biogas was studied using the Optima-7 Biogas gas analyzer. (Results and discussion) The article presents a process model and a technical appearance of an installation for producing gas motor fuel from the biogas of anaerobic digestion of organic waste of the agro-industrial complex. The hydrate formation time depends on the increase in the interfacial surface and the movement of gas bubbles relative to the liquid, which can be regulated by acting on the hydrate formation zone (shock wave, electromagnetic, mechanical, chemical, temperature). (Conclusions) The research results can be used in modeling processes in two-phase media during the formation of gas hydrates and the creation of installations for their production.

Application of Machine Learning in Gas-Hydrate Formation and Trendline Prediction

2021 ◽  
Author(s):  
Celestine Udim Monday ◽  
Toyin Olabisi Odutola
Keyword(s):  
Machine Learning ◽  
Deep Learning ◽  
Natural Gas ◽  
Gas Hydrate ◽  
Gas Flow ◽  
Flow Line ◽  
Learning Algorithms ◽  
Hydrate Formation ◽  
Machine Learning Algorithms ◽  
Gas Hydrate Formation

Abstract Natural Gas production and transportation are at risk of Gas hydrate plugging especially when in offshore environments where temperature is low and pressure is high. These plugs can eventually block the pipeline, increase back pressure, stop production and ultimately rupture gas pipelines. This study seeks to develops machine learning models after a kinetic inhibitor to predict the gas hydrate formation and pressure changes within the natural gas flow line. Green hydrate inhibitor A, B and C were obtained as plant extracts and applied in low dosages (0.01 wt.% to 0.1 wt.%) on a 12meter skid-mounted hydrate closed flow loop. From the data generated, the optimal dosages of inhibitor A, B and C were observed to be 0.02 wt.%, 0.06 wt.% and 0.1 wt.% respectively. The data associated with these optimal dosages were fed to a set of supervised machine learning algorithms (Extreme gradient boost, Gradient boost regressor and Linear regressor) and a deep learning algorithm (Artificial Neural Network). The output results from the set of supervised learning algorithms and Deep Learning algorithms were compared in terms of their accuracies in predicting the hydrate formation and the pressure within the natural gas flow line. All models had accuracies greater than 90%. This result show that the application Machine learning to solving flow assurance problems is viable. The results show that it is viable to apply machine learning algorithms to solve flow assurance problems, analyzing data and getting reports which can improve accuracy and speed of on-site decision making process.

Coupled Heat and Mass Transfer CFD Model for Methane Hydrate

2015 ◽  
Author(s):  
Eugenio Turco Neto ◽  
M. A. Rahman ◽  
Syed Imtiaz ◽  
Thiago dos Santos Pereira ◽  
Fernanda Soares de Sousa
Keyword(s):  
Natural Gas ◽  
Multiphase Flow ◽  
Gas Hydrate ◽  
Gas Flow ◽  
Three Dimensional ◽  
Hydrate Formation ◽  
Cfd Model ◽  
Flow Metering ◽  
Ansys Cfx ◽  
Gas Hydrate Formation

The gas hydrates problem has been growing in offshore deep water condition where due to low temperature and high pressure hydrate formation becomes more favorable. Several studies have been done to predict the influence of gas hydrate formation in natural gas flow pipeline. However, the effects of multiphase hydrodynamic properties on hydrate formation are missing in these studies. The use of CFD to simulate gas hydrate formation can overcome this gap. In this study a computational fluid dynamics (CFD) model has been developed for mass, heat and momentum transfer for better understanding natural gas hydrate formation and its migration into the pipelines using ANSYS CFX-14. The problem considered in this study is a three-dimensional multiphase-flow model based on Simon Lo (2003) study, which considered the oil-dominant flow in a pipeline with hydrate formation around water droplets dispersed into the oil phase. The results obtained in this study will be useful in designing a multiphase flow metering and a pump to overcome the pressure drop caused by hydrate formation in multiphase petroleum production.

scholarly journals Artificial Neural Network-based detection of gas hydrate formation

ACTA IMEKO ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 117
Author(s):  
Ildikó Bölkény
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Gas Hydrate ◽  
Gas Flow ◽  
Hydrate Formation ◽  
Gas Well ◽  
Low Concentrations ◽  
Gas Hydrate Formation ◽  
Artificial Neural ◽  
Artificial Neural Network Ann

In the production process of natural gas one of the major problems is the formation of hydrate crystals creating hydrate plugs in the pipeline. The hydrate plugs increase production losses, because the removal of the plugs is a high cost, time consuming procedure. One of the solutions used to prevent hydrate formation is the injection of modern compositions to the gas flow, helping to dehydrate the gas. Dehydratation obviously means that the size of hydrate crystals does not increase. The substances used in low concentrations, have to be locally injected at the gas well sites. Inhibitor dosing depends on the amount of gas hydrate present. In the article two Artificial Neural Network (ANN)-based predictive detection solutions are presented. In both cases the goal is to predict hydrate formation. Data used come from two solutions. In the first one measurements were performed by a self-developed and -produced equipment in this case, differential pressure was used as input. In the second solution data are used from the measurement system of a motorised chemical-injector device, in this case pressure, temperature, quantity and type of inhibitor were used as inputs. Both systems are presented in the article.

scholarly journals Investigation on Gas Hydrates Formation and Dissociation in Multiphase Gas Dominant Transmission Pipelines

2020 ◽  
Vol 10 (15) ◽  
pp. 5052 ◽  
Author(s):  
Sayani Jai Krishna Sahith ◽  
Srinivasa Rao Pedapati ◽  
Bhajan Lal
Keyword(s):  
Crude Oil ◽  
Phase Behavior ◽  
Gas Hydrates ◽  
Gas Hydrate ◽  
Formation Rate ◽  
Water System ◽  
Hydrate Formation ◽  
Multiphase System ◽  
Gas Hydrate Formation ◽  
Water Cut

In this work, a gas hydrate formation and dissociation study was performed on two multiphase pipeline systems containing gasoline, CO2, water, and crude oil, CO2, water, in the pressure range of 2.5–3.5 MPa with fixed water cut as 15% using gas hydrate rocking cell equipment. The system has 10, 15 and 20 wt.% concentrations of gasoline and crude oil, respectively. From the obtained hydrate-liquid-vapor-equilibrium (HLVE) data, the phase diagrams for the system are constructed and analyzed to represent the phase behavior in the multiphase pipelines. Similarly, induction time and rate of gas hydrate formation studies were performed for gasoline, CO2, and water, and crude oil, CO2, water system. From the evaluation of phase behavior based on the HLVE curve, the multiphase system with gasoline exhibits an inhibition in gas hydrates formation, as the HLVE curve shifts towards the lower temperature and higher-pressure region. The multiphase system containing the crude oil system shows a promotion of gas hydrates formation, as the HLVE curve shifted towards the higher temperature and lower pressure. Similarly, the kinetics of hydrate formation of gas hydrates in the gasoline system is slow. At the same time, crude oil has a rapid gas hydrate formation rate.

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