Numerical Simulation of Hydrate Transport in Natural Gas Pipeline

1998 ◽  
Vol 120 (1) ◽  
pp. 20-26 ◽  
Author(s):  
S. O. Ibraheem ◽  
M. A. Adewumi ◽  
J. L. Savidge
Keyword(s):  
Natural Gas ◽  
Fluid Model ◽  
Hydrate Formation ◽  
Higher Order ◽  
Solid Particles ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
Offshore Production ◽  
Two Fluid Model ◽  
Viable Approach

Accurate modeling of hydrate transportation in natural gas pipelines is becoming increasingly important in the design and operation of offshore production facilities. The dynamics involved in the formation of hydrate particles and in its transportation are governed by the multiphase hydrodynamics equations ensuing from the balance of mass, momentum, and energy. In this study, a two-fluid model is solved to characterize particulate transportation. The numerical algorithm employed is stable and robust and it is based on higher-order schemes. This is necessary since the governing equations describing the simultaneous flow of gas and solid particles are hyperbolic and, thus, admit discontinuities. Specialized higher-order schemes provide a viable approach for efficient frontal tracking of continuity waves in particular. Several simulation experiments that can facilitate thorough understanding of the design and maintenance of pipelines susceptible to hydrate formation are presented.

A Unified Two-Fluid Model for Multiphase Flow in Natural Gas Pipelines

2002 ◽  
Author(s):  
Luis F. Ayala ◽  
Eltohami S. Eltohami ◽  
Michael A. Adewumi
Keyword(s):  
Natural Gas ◽  
Hydrodynamic Model ◽  
Fluid Model ◽  
Liquid Loading ◽  
Two Phase ◽  
Natural Gas Pipelines ◽  
Fluid Velocities ◽  
Two Fluid Model ◽  
Two Fluid ◽  
Equilibrium Calculations

A unified two-fluid model for multiphase natural gas and condensate flow in pipelines is presented. The hydrodynamic model consists of steady-state one-dimensional mass and continuity balances for each phase and a combined energy equation to give a system of five first-order ordinary differential equations. The hydrodynamic model is coupled with a phase behavior model based on the Peng-Robinson equation of state to handle the vapor-/liquid equilibrium calculations and thermodynamic property predictions. The model handles single and two-phase flow conditions and is able to predict the transition between them. It also generates profiles for pressure, temperature, and the fluid velocities in both phases as well as their holdups. The expected flow patterns as well as their transitions are modeled with emphasis on the low liquid loading character of such systems. The expected flow regimes for this system are dispersed liquid, annular-mist, stratified smooth as well as stratified wavy.

Low-Liquid Loading Multiphase Flow in Natural Gas Pipelines

2003 ◽  
Vol 125 (4) ◽  
pp. 284-293 ◽  
Author(s):  
Luis F. Ayala ◽  
Michael A. Adewumi
Keyword(s):  
Natural Gas ◽  
Fluid Model ◽  
Fluid Phase ◽  
Gas Flows ◽  
Gas Pipelines ◽  
Liquid Loading ◽  
Gas Condensation ◽  
Natural Gas Pipelines ◽  
The Common ◽  
Two Fluid Model

Pressure and temperature variations of natural gas flows in a pipeline may cause partial gas condensation. Fluid phase behavior and prevailing conditions often make liquid appearance inevitable, which subjects the pipe flow to a higher pressure loss. This study focuses on the hydrodynamic behavior of the common scenarios that may occur in natural gas pipelines. For this purpose, a two-fluid model is used. The expected flow patterns as well as their transitions are modeled with emphasis on the low-liquid loading character of such systems. In addition, the work re-examines previous implementations of two-flow model for gas-condensate flow.

scholarly journals Numerical Analysis of the Characteristics of Gas Explosion Process in Natural Gas Compartment of Utility Tunnel Using FLACS

2019 ◽  
Vol 12 (1) ◽  
pp. 153 ◽  
Author(s):  
Zexu Li ◽  
Jiansong Wu ◽  
Mingyu Liu ◽  
Yuntao Li ◽  
Qiuju Ma
Keyword(s):  
Natural Gas ◽  
Gas Explosion ◽  
Rapid Urbanization ◽  
Flame Acceleration ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
Urban Safety ◽  
Fire And Explosion ◽  
Utility Tunnel ◽  
Urbanization In China

With the rapid urbanization in China, directly buried municipal pipelines have been gradually replaced by urban utility tunnels due to a serious shortage of urban underground spaces and weak disaster prevention of traditional municipal pipelines. The urban utility tunnels normally contain electricity pipelines, natural gas pipelines, heat pipelines, sewer pipelines, etc. If a natural gas pipeline leaks, a fire and explosion might occur and lead to serious consequences. In this study, the characteristics of gas explosion in a natural gas compartment of urban utility tunnel are investigated based on FLACS (Flame Acceleration Simulator) simulations. The results revealed that the flame profile undergoes two unstable flame stages. When the ignition position is set at the middle area (100.25, 1.2, 1.4 m) of the 200 m-long natural gas compartment, the maximum overpressure of the gas explosion in the 200 m-long natural gas compartment is 25.17 bar, which is the largest maximum overpressure under all gas explosion simulation setups. It is also found that the length of the natural gas compartment and different ignition positions have slight effects on the maximum overpressure. This study could provide technical support for structural strength design and division of the fireproofing area of the natural gas compartment in the utility tunnel, which is of great significance to improve urban safety during sustainable development.

scholarly journals Computational investigation of liquid-solid slurry flow through an expansion in a rectangular duct

2014 ◽  
Vol 62 (3) ◽  
pp. 234-240 ◽  
Author(s):  
Gianandrea Vittorio Messa ◽  
Stefano Malavasi
Keyword(s):  
Volume Fraction ◽  
Particle Density ◽  
Fluid Model ◽  
Solid Volume Fraction ◽  
Solid Particles ◽  
Rectangular Duct ◽  
Two Phase ◽  
Horizontal Pipe ◽  
Two Fluid Model ◽  
Two Fluid

Abstract The flow of a mixture of liquid and solid particles at medium and high volume fraction through an expansion in a rectangular duct is considered. In order to improve the modelling of the phenomenon with respect to a previous investigation (Messa and Malavasi, 2013), use is made of a two-fluid model specifically derived for dense flows that we developed and implemented in the PHOENICS code via user-defined subroutines. Due to the lack of experimental data, the two-fluid model was validated in the horizontal pipe case, reporting good agreement with measurements from different authors for fully-suspended flows. A 3D system is simulated in order to account for the effect of side walls. A wider range of the parameters characterizing the mixture (particle size, particle density, and delivered solid volume fraction) is considered. A parametric analysis is performed to investigate the role played by the key physical mechanisms on the development of the two-phase flow for different compositions of the mixture. The main focuses are the distribution of the particles in the system and the pressure recovery

Steady State Performance Simulation of Natural Gas Pipeline Driven by Compressor Stations

2016 ◽  
Author(s):  
S. M. Suleiman ◽  
Y. G. Li
Keyword(s):  
Steady State ◽  
Natural Gas ◽  
Flow Rate ◽  
Operating Conditions ◽  
Simulation Approach ◽  
Gas Pipelines ◽  
Performance Simulation ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
Pumping Stations

Natural gas pipeline plays an important role in transporting natural gas over a long distance. Its performance and operating behavior are affected by many factors, such as ambient conditions, natural gas flow rate, operation and control of compressor pumping stations, etc. Better understanding of the performance and behavior of an integrated pipeline-compressor system used for gas transmission will be beneficial to both design and operation of natural gas pipelines. This paper introduces a novel steady-state thermodynamic performance simulation approach for natural gas pipelines based on fundamental thermodynamics with the inclusion of the coupling between a pipeline and compressor pumping stations. A pipeline resistance model, a compressor performance model characterized by an empirical compressor map and a pipeline control schedule for the operation of an integrated pipeline-compressor system are included in the simulation approach. The novel approach presented in this paper allows the analysis of the thermodynamic coupling between compressors and pipes and the off-design performance analysis of the integrated pipeline-compressor system. The introduced simulation approach has been applied to the performance simulation of a typical model pipeline driven by multiple centrifugal compressor pumping stations. It is assumed in the pipeline control schedule that the total pressure at the inlet of compressor stations is kept constant when pipeline operating condition changes. Such pipeline operating conditions include varying ambient temperature and varying natural gas volumetric flow rate. The performance behavior of the pipeline corresponding to the change of operating conditions has been successfully simulated. The introduced pipeline performance simulation approach is generic and can be applied to different pipeline-compressor systems.

scholarly journals Options of Natural Gas Pipeline Reassignment for Hydrogen: Cost Assessment for a Germany Case Study

2019 ◽  
Author(s):  
Simonas Cerniauskas ◽  
Antonio Jose Chavez Junco ◽  
Thomas Grube ◽  
Martin Robinius ◽  
Detlef Stolten
Keyword(s):  
Natural Gas ◽  
Energy System ◽  
Gas Pipeline ◽  
Cost Functions ◽  
Pipeline System ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
System P ◽  
Availability Constraints ◽  
Hydrogen Supply

The uncertain role of the natural gas infrastructure in the decarbonized energy system and the limitations of hydrogen blending raise the question of whether natural gas pipelines can be economically utilized for the transport of hydrogen. To investigate this question, this study derives cost functions for the selected pipeline reassignment methods. By applying geospatial hydrogen supply chain modeling, the technical and economic potential of natural gas pipeline reassignment during a hydrogen market introduction is assessed.The results of this study show a technically viable potential of more than 80% of the analyzed representative German pipeline network. By comparing the derived pipeline cost functions it could be derived that pipeline reassignment can reduce the hydrogen transmission costs by more than 60%. Finally, a countrywide analysis of pipeline availability constraints for the year 2030 shows a cost reduction of the transmission system by 30% in comparison to a newly built hydrogen pipeline system.

Reliability Calculation Method for Natural Gas Pipelines with Girth Weld Defects Identified through In-Line Inspection

2019 ◽  
Vol 795 ◽  
pp. 225-232 ◽  
Author(s):  
Ming Fei Li ◽  
Jian Chen ◽  
Zheng Qiang Lei ◽  
Hong Long Zheng ◽  
Zai Rong Li
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
Plastic Material ◽  
Pipeline System ◽  
Long Distance ◽  
Weld Defects ◽  
Natural Gas Pipelines ◽  
Natural Gas Pipeline ◽  
The Monte Carlo Method ◽  
Reliability Assessments

To introduce a method for reliability analysis of China's large-scale natural gas pipeline system, one should first have a method to calculate the reliability of pipe segments, compressors, valves, and other factors. This article models the rules prescribed in BS7910-2013, a guide to methods for assessing the acceptability of flaws in metallic structures, and combines pipeline reliability assessments from CSA Z662-2015 to present a method (based on the Monte Carlo method) to calculate the failure probability/reliability of long-distance pipelines containing a large number of girth weld defects. The method involves the destruction of plastic material, brittle fracture failure analysis, consideration of the division of units by using pipeline area classes for calculation, and reliability index analysis. The results of a magnetic flux leakage (MFL) in-line inspection (ILI) of a defective girth weld from a section of a pipeline in China are used to demonstrate how to determine the reliability of the entire pipeline.

Sign in / Sign up

Export Citation Format

Share Document