CFD Investigation of Downhole Natural Gas Separation Efficiency in the Churn Flow Regime

2021 ◽  
Author(s):  
Charles Okafor ◽  
Patrick Verdin ◽  
Phill Hart
Keyword(s):  
Natural Gas ◽  
Flow Regime ◽  
Gas Separation ◽  
Separation Efficiency ◽  
Operating Conditions ◽  
Analytical Models ◽  
Design Stage ◽  
Average Error ◽  
Multiphase Model ◽  
Churn Flow

Abstract Downhole Natural Gas Separation Efficiency (NGSE) is flow regime dependent, and current analytical models in certain conditions lack accuracy. Downhole NGSE was investigated through 3D Computational Fluid Dynamics (CFD) transient simulations for pumping wells in the Churn flow regime. The Volume of Fluid (VOF) multiphase model was considered along with the k – ε turbulence model for most simulations. A mesh independence study was performed, and the final model results validated against experimental data, showing an average error of less than 6 %. Numerical simulation results showed that the steady state assumption used by current mathematical models for churn flow can be inaccurate. Several key parameters affecting the NGSE were identified, and suggestions for key improvements to the widely used mathematical formulations for viscous flow provided. Sensitivity studies were conducted on fluid/geometric parameters and operating conditions, to gain a better understanding of the influence of each parameter on NGSE. These are important results as they equip the ESP engineer with additional knowledge to maximise the NGSE from design stage to pumping operations.

A Simple Model To Predict Natural Gas Separation Efficiency in Pumped Wells

2003 ◽  
Vol 18 (01) ◽  
pp. 5-12 ◽  
Author(s):  
A.F. Harun ◽  
M.G. Prado ◽  
J.C. Serrano ◽  
D.R. Doty
Keyword(s):  
Simple Model ◽  
Natural Gas ◽  
Gas Separation ◽  
Separation Efficiency

A Simple Model To Predict Natural Gas Separation Efficiency in Pumped Wells

2000 ◽  
Author(s):  
A.F. Harun ◽  
M.G. Prado ◽  
J.C. Serrano ◽  
D.R. Doty
Keyword(s):  
Simple Model ◽  
Natural Gas ◽  
Gas Separation ◽  
Separation Efficiency

scholarly journals CFD Simulation for Separation of Carbon Dioxide-Methane Mixture by Pressure Swing Adsorption

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
K. Rambabu ◽  
L. Muruganandam ◽  
S. Velu
Keyword(s):  
Carbon Dioxide ◽  
Flow Rate ◽  
Pressure Swing Adsorption ◽  
Cfd Simulation ◽  
Separation Efficiency ◽  
Carbon Dioxide Concentration ◽  
Operating Conditions ◽  
Analytical Models ◽  
Feed Mixture ◽  
Pressure Swing

A developing technology for gas separations is pressure swing adsorption, which has been proven to be more economical and energy efficient compared to other separation methods like cryogenic distillation and membrane separation. A pressure swing adsorption (PSA) column, with carbon dioxide-methane as feed mixture and 6-FDA based polyimides as the adsorbent, was modeled and simulated in this work. Ansys Fluent 12.1, along with supplementary user defined functions, was used to develop a 2D transient Eulerian laminar viscous flow model for the PSA column. The model was validated by comparing the simulated results with established analytical models for PSA. The developed numerical model was used to determine the carbon dioxide concentration in the column as a function of time based on different operating conditions. Effect of various operating parameters like pressure, temperature, and flow rate on the separation efficiency has been studied and reported. Optimization studies were carried out to obtain suitable operating conditions for the feed gases separation. Simulation studies were carried out to determine the separation length required for complete separation of the feed mixture corresponding to different inlet feed concentrations which were entering the column at a given flow rate.

IMPROVED INFLOW PERFORMANCE RELATIONSHIPS AND IMPROVED WELL BORE PERFORMANCE

2005 ◽  
Vol 45 (1) ◽  
pp. 27
Author(s):  
R.J. Watson
Keyword(s):  
Flow Regime ◽  
Gas Separation ◽  
Separation Efficiency ◽  
Well Bore ◽  
Pump Performance ◽  
Qualitative Estimate ◽  
Water Cut ◽  
Regime Map ◽  
Inflow Performance ◽  
Flow Regime Map

The inflow performance relationship for oil proposed by Vogel (1968) and extended by Brown (1981) has been modified empirically to allow for variations in water cut and gas liquid ratio.The well bore performance of wells flowing or gas lifting continuously is known to be affected adversely by the separation of fluids at the eductor (tubing or annulus) intake. Performance is affected mostly in wells with large well bore storage.The design of the tubing intake also affects separation. A tubing intake that will reduce separation in flowing wells and increase separation in pumped wells has been designed and tested in a transparent model.A qualitative estimate of the gas separation efficiency of this device has been made. The estimate is based on the Ros (1961) flow regime map and on observations by Beggs and Brill (1973) that liquid hold-up increases with well deviation up to 40º. Further tests are warranted.Rod pump performance is analysed in detail. A spreadsheet allows comparison of pump capacity with well inflowperformance.Even at very low gas/liquid ratios, gas separation at the tubing intake affects significantly both single and two stage pump performance.

scholarly journals Natural gas sweetening polymeric membrane: Established optimum operating condition at 70% of CO2 concentration feed gas stream

2020 ◽  
Vol 16 (1) ◽  
pp. 54-58
Author(s):  
M. H. M. Halim ◽  
F. Kadirkhan ◽  
W. N. F. W. Mustapa ◽  
W. K. Soh ◽  
S. Y. Yeo
Keyword(s):  
Natural Gas ◽  
Gas Separation ◽  
Co2 Concentration ◽  
Operating Conditions ◽  
Separation Performance ◽  
Co2 Gas ◽  
High Co2 ◽  
Gas Sweetening ◽  
Gas Separation Performance ◽  
Natural Gas Sweetening

PETRONAS embarks on breakthrough technology for natural gas sweetening in high CO2 gas fields. Membrane technology is found to be one with high potential and a promising technology for bulk CO2 removal from natural gas. It can be suited to wide operating conditions to process varied natural gas composition, pressure and temperature. This paper focuses on the extensive development of PETRONAS in-house membrane and its evaluation for gas separation performance for high CO2 feed gas at different operating conditions; eg. feed gas flowrate, temperature, pressure, CO2 concentration in mixed gas system, and permeate pressure. For all the cases in this study, samples were tested at optimum gas flowrate of 1000 standard cm3/min (sccm) to obtain representative membrane performance. Feed gas pressure and CO2 concentration have shown significantly affect membrane permeation properties; whereas feed gas temperature and permeate pressure showed negligible impact. There is a trade-off between permeance and selectivity when CO2 concentration is increased from 40% to 70%; where the CO2 permeance increased by 12% which consequently reduces CO2/CH4 selectivity by 15%. In summary, the membrane developed in this study demonstrates high pressure durability up to 50 bar and temperature up to 55oC with satisfactory gas separation performance in the presence of high CO2 concentration in feed gas (up to 70% CO2). This work is breakthrough in establishing the operational boundary of PETRONAS Membrane for technology development and deployment in monetizing high CO2 gas field.

Investigations of Road Wear Caused by Studded Tires

2014 ◽  
Vol 42 (1) ◽  
pp. 2-15
Author(s):  
Johannes Gültlinger ◽  
Frank Gauterin ◽  
Christian Brandau ◽  
Jan Schlittenhard ◽  
Burkhard Wies
Keyword(s):  
Traffic Safety ◽  
Test Bench ◽  
Operating Conditions ◽  
Test Method ◽  
Analytical Models ◽  
The Road ◽  
Driving Speed ◽  
Major Factors ◽  
Tire Friction ◽  
Variable Operating Conditions

ABSTRACT The use of studded tires has been a subject of controversy from the time they came into market. While studded tires contribute to traffic safety under severe winter conditions by increasing tire friction on icy roads, they also cause damage to the road surface when running on bare roads. Consequently, one of the main challenges in studded tire development is to reduce road wear while still ensuring a good grip on ice. Therefore, a research project was initiated to gain understanding about the mechanisms and influencing parameters involved in road wear by studded tires. A test method using the institute's internal drum test bench was developed. Furthermore, mechanisms causing road wear by studded tires were derived from basic analytical models. These mechanisms were used to identify the main parameters influencing road wear by studded tires. Using experimental results obtained with the test method developed, the expected influences were verified. Vehicle driving speed and stud mass were found to be major factors influencing road wear. This can be explained by the stud impact as a dominant mechanism. By means of the test method presented, quantified and comparable data for road wear caused by studded tires under controllable conditions can be obtained. The mechanisms allow predicting the influence of tire construction and variable operating conditions on road wear.

"Recent Patents on the Triboelectrostatic Separation of Fly Ash"

2019 ◽  
Vol 13 ◽  
Author(s):  
Haisheng Li ◽  
Wenping Wang ◽  
Yinghua Chen ◽  
Xinxi Zhang ◽  
Chaoyong Li
Keyword(s):  
Fly Ash ◽  
Power Plants ◽  
High Efficiency ◽  
Separation Efficiency ◽  
High Reliability ◽  
Operating Conditions ◽  
Security Requirements ◽  
Unburned Carbon ◽  
Efficient Operation ◽  
Triboelectrostatic Separation

Background: The fly ash produced by coal-fired power plants is an industrial waste. The environmental pollution problems caused by fly ash have been widely of public environmental concern. As a waste of recoverable resources, it can be used in the field of building materials, agricultural fertilizers, environmental materials, new materials, etc. Unburned carbon content in fly ash has an influence on the performance of resource reuse products. Therefore, it is the key to remove unburned carbon from fly ash. As a physical method, triboelectrostatic separation technology has been widely used because of obvious advantages, such as high-efficiency, simple process, high reliability, without water resources consumption and secondary pollution. Objective: The related patents of fly ash triboelectrostatic separation had been reviewed. The structural characteristics and working principle of these patents are analyzed in detail. The results can provide some meaningful references for the improvement of separation efficiency and optimal design. Methods: Based on the comparative analysis for the latest patents related to fly ash triboelectrostatic separation, the future development is presented. Results: The patents focused on the charging efficiency and separation efficiency. Studies show that remarkable improvements have been achieved for the fly ash triboelectrostatic separation. Some patents have been used in industrial production. Conclusion: According to the current technology status, the researches related to process optimization and anti-interference ability will be beneficial to overcome the influence of operating conditions and complex environment, and meet system security requirements. The intelligent control can not only ensure the process continuity and stability, but also realize the efficient operation and management automatically. Meanwhile, the researchers should pay more attention to the resource utilization of fly ash processed by triboelectrostatic separation.

Role of Reynolds and Archimedes numbers in particle-fluid flows

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Haim Kalman
Keyword(s):  
Flow Regime ◽  
Power Function ◽  
Fluid Flows ◽  
Limited Range ◽  
Operating Conditions ◽  
Pneumatic Conveying ◽  
Particulate Materials ◽  
Simple Power ◽  
Simple Power Function

AbstractAny scientific behavior is best represented by nondimensional numbers. However, in many cases, for pneumatic conveying systems, dimensional equations are developed and used. In some cases, many of the nondimensional equations include Reynolds (Re) and Froude (Fr) numbers; they are usually defined for a limited range of materials and operating conditions. This study demonstrates that most of the relevant flow types, whether in horizontal or vertical pipes, can be better described by Re and Archimedes (Ar) numbers. Ar can also be used in hydraulic conveying systems. This paper presents many threshold velocities that are accurately defined by Re as a simple power function of Ar. Many particulate materials are considered by Ar, thereby linking them to a common behavior. Using various threshold velocities, a flow regime chart for horizontal conveying is presented in this paper.

A phenomenological model for the description of unburned hydrocarbons emission in ultra-lean engines

2021 ◽  
pp. 146808742110050
Author(s):  
Enrica Malfi ◽  
Vincenzo De Bellis ◽  
Fabio Bozza ◽  
Alberto Cafari ◽  
Gennaro Caputo ◽  
...  
Keyword(s):  
Natural Gas ◽  
Internal Combustion Engines ◽  
Pollutant Emissions ◽  
Average Error ◽  
Combustion Engines ◽  
Nitric Oxides ◽  
Lean Burn ◽  
Fuel Charge ◽  
Unburned Hydrocarbons ◽  
Model Reliability

The adoption of lean-burn concepts for internal combustion engines working with a homogenous air/fuel charge is under development as a path to simultaneously improve thermal efficiency, fuel consumption, nitric oxides, and carbon monoxide emissions. This technology may lead to a relevant emission of unburned hydrocarbons (uHC) compared to a stoichiometric engine. The uHC sources are various and the relative importance varies according to fuel characteristics, engine operating point, and some geometrical details of the combustion chamber. This concern becomes even more relevant in the case of engines supplied with natural gas since the methane has a global warming potential much greater than the other major pollutant emissions. In this work, a simulation model describing the main mechanisms for uHC formation is proposed. The model describes uHC production from crevices and flame wall quenching, also considering the post-oxidation. The uHC model is implemented in commercial software (GT-Power) under the form of “user routine”. It is validated with reference to two large bore engines, whose bores are 31 and 46 cm (engines named accordingly W31 and W46). Both engines are fueled with natural gas and operated with lean mixtures (λ > 2), but with different ignition modalities (pre-chamber device or dual fuel mode). The engines under study are preliminarily schematized in the 1D simulation tool. The consistency of 1D engine schematizations is verified against the experimental data of BMEP, air flow rate, and turbocharger rotational speed over a load sweep. Then, the uHC model is validated against the engine-out measurements. The averaged uHC predictions highlight an average error of 7% and 10 % for W31 and W46 engines, respectively. The uHC model reliability is evidenced by the lack of need for a case-dependent adjustment of its tuning constants, also in presence of relevant variations of both engine load and ring pack design.

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