Study on the Pigging Process of Rich Gas Pipeline

2014 ◽  
Vol 884-885 ◽  
pp. 242-246
Author(s):  
Wei Qiang Wang ◽  
Kai Feng Fan ◽  
Yu Fei Wan ◽  
Ming Wu ◽  
Le Yang
Keyword(s):  
Natural Gas ◽  
Flow Pattern ◽  
Fluid Model ◽  
Simulation Software ◽  
Gas Pipeline ◽  
Liquid Holdup ◽  
Two Phase ◽  
Natural Gas Pipeline ◽  
Fluid Transient ◽  
Safety Operation

Intensive study on flowing properties of two-phase fluid of gas and liquid during pipeline pigging helps to improve the safety operation of rich gas pipeline. Therefore, based on the multiphase fluid transient simulation software, a two-fluid model is employed to study the flowing regulation of gas and liquid in practical operation of natural gas pipeline pigging,especially the change rule of velocity,flow pattern, pressure, liquid holdup ratio, and liquid slug in the passing ball process. The results reveal that three flow patterns appeared in pipeline pigging. They are stratified flow, slug flow and bubble flow. The place where the particular flow pattern appears is related to the terrain. The biggest pressure is found at the entrance, then pressure comes down along the pipeline, and fluctuate according to the fluid amount and terrain; the transient velocity of pig is coherent with the terrain and liquid holdup ratio; small slug flows are easy to gather and form into a longer one. The research can somehow guide to the safety operation of natural gas pipeline pigging.

scholarly journals GPU-accelerated hydraulic simulations of large-scale natural gas pipeline networks based on a two-level parallel process

2020 ◽  
Vol 75 ◽  
pp. 86
Author(s):  
Yue Xiang ◽  
Peng Wang ◽  
Bo Yu ◽  
Dongliang Sun
Keyword(s):  
Natural Gas ◽  
Large Scale ◽  
Parallel Simulation ◽  
Simulation Software ◽  
Gas Pipeline ◽  
Processing Unit ◽  
Pipeline Network ◽  
Natural Gas Pipeline ◽  
Pipeline Networks ◽  
Speedup Ratio

The numerical simulation efficiency of large-scale natural gas pipeline network is usually unsatisfactory. In this paper, Graphics Processing Unit (GPU)-accelerated hydraulic simulations for large-scale natural gas pipeline networks are presented. First, based on the Decoupled Implicit Method for Efficient Network Simulation (DIMENS) method, presented in our previous study, a novel two-level parallel simulation process and the corresponding parallel numerical method for hydraulic simulations of natural gas pipeline networks are proposed. Then, the implementation of the two-level parallel simulation in GPU is introduced in detail. Finally, some numerical experiments are provided to test the performance of the proposed method. The results show that the proposed method has notable speedup. For five large-scale pipe networks, compared with the well-known commercial simulation software SPS, the speedup ratio of the proposed method is up to 57.57 with comparable calculation accuracy. It is more inspiring that the proposed method has strong adaptability to the large pipeline networks, the larger the pipeline network is, the larger speedup ratio of the proposed method is. The speedup ratio of the GPU method approximately linearly depends on the total discrete points of the network.

Dynamic Simulation of Gas-Liquid Homogeneous Flow in Natural Gas Pipeline Using Two-Fluid Conservation Equations

2005 ◽  
Author(s):  
Mohammad Abbaspour ◽  
Kirby S. Chapman ◽  
Larry A. Glasgow ◽  
Zhongquan C. Zheng
Keyword(s):  
Natural Gas ◽  
Large Time ◽  
Gas Pipeline ◽  
Phase Flow ◽  
Time Step ◽  
Two Phase ◽  
Natural Gas Pipeline ◽  
Fully Implicit ◽  
Large Time Step ◽  
Two Fluid

Homogeneous two-phase flows are frequently encountered in a variety processes in the petroleum and gas industries. In natural gas pipelines, liquid condensation occurs due to the thermodynamic and hydrodynamic imperatives. During horizontal, concurrent gas-liquid flow in pipes, a variety of flow patterns can exist. Each pattern results from the particular manner by which the liquid and gas distribute in the pipe. The objective of this study is to simulate the non-isothermal, one-dimensional, transient homogenous two-phase flow gas pipeline system using two-fluid conservation equations. The modified Peng-Robinson equation of state is used to calculate the vapor-liquid equilibrium in multi-component natural gas to find the vapor and liquid compressibility factors. Mass transfer between the gas and the liquid phases is treated rigorously through flash calculation, making the algorithm capable of handling retrograde condensation. The liquid droplets are assumed to be spheres of uniform size, evenly dispersed throughout the gas phase. The method of solution is the fully implicit finite difference method. This method is stable for gas pipeline simulations when using a large time step and therefore minimizes the computation time. The algorithm used to solve the nonlinear finite-difference thermo-fluid equations for two phase flow through a pipe is based on the Newton-Raphson method. The results show that the liquid condensate holdup is a strong function of temperature, pressure, mass flow rate, and mixture composition. Also, the fully implicit method has advantages, such as the guaranteed stability for large time step, which is very useful for simulating long-term transients in natural gas pipeline systems.

Calculation on Friction Pressure Gradient of Gas-Liquid Stratified Flows in Condensate Natural Gas Pipeline

2011 ◽  
Vol 356-360 ◽  
pp. 875-880
Author(s):  
Rong Ge Xiao ◽  
Bing Qian Wei ◽  
Gang Chen
Keyword(s):  
Natural Gas ◽  
Pressure Gradient ◽  
Large Scale ◽  
Flow Characteristics ◽  
Gas Pipeline ◽  
Stratified Flows ◽  
Momentum Balance ◽  
Two Phase ◽  
Natural Gas Pipeline ◽  
Liquid Flows

Flow characteristics of horizontal two-phase gas-liquid stratified flows in condensate natural gas pipeline are studied through both air-water and air- natural gas condensate experiments on the large-scale multiphase experimental loop. Based on measurement and observation of flow pattern, “apparent rough surface” (ARS) model is selected to calculate frictional pressure gradient with gas-liquid momentum balance equations. The predictions of the models are compared with the data measured in the experiment. Some results of pressure gradient are obtained, so ARS interfacial shape is recommended in horizontal two-phase gas-liquid flows with low liquid loading.

scholarly journals Research on Critical Effusion Volume for the China-Burma Natural Gas Pipeline

2016 ◽  
Vol 10 (1) ◽  
pp. 461-468
Author(s):  
Xiyao Liu ◽  
Changjun Li ◽  
Yang Peng ◽  
Yanjie Jia ◽  
Chunqing Li
Keyword(s):  
Natural Gas ◽  
Prediction Model ◽  
Gas Pipeline ◽  
Analysis Software ◽  
Liquid Holdup ◽  
Natural Gas Pipeline ◽  
Gas Condensates ◽  
Temperature And Pressure ◽  
Gas Supply

Under certain temperature and pressure conditions, natural gas condensates and the liquid is accumulated in the pipeline during transmission of gas. It is therefore important to calculate the critical effusion volume accurately so that a reasonable pigging cycle can be determined. Frequent pigging operation not only affects the normal gas supply, but also causes unpiggable obstacles. This study has developed a liquid prediction model in which the effusion volume is dependent on the liquid holdup and the capacity of the gas to carry liquid. Using the analysis software OLGA and applying the model to the China-Burma pipeline, the critical effusion volume and the parameters distribution curves along the pipeline have been determined. The results show that the critical effusion volume in the pipeline decreases with increasing throughput. The method is a significant advancement in determining the pigging cycle and mitigating the pigging risk.

scholarly journals The Influence of Rescheduled-Overhaul in determining the number of Gas turbine Usage in Natural Gas Pipeline Transportation Network

2020 ◽  
Vol 1 (1) ◽  
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Simulation Software ◽  
Gas Pipeline ◽  
Baseline Condition ◽  
Single Type ◽  
Compressor Station ◽  
Natural Gas Pipeline ◽  
Baseline Case ◽  
Engine Life

Gas turbines are an integral part of the supply of natural gas in many parts of the world. In compressor stations, they are used for transporting gas from producing wells to consumers and across extensive networks of pipelines. This paper present how rescheduling of gas turbine overhaul from the baseline condition amid degradation influences the number of the gas turbine to be used in a compressor station without altering the original pipeline design for the desired amount of gas delivery. Eighteen compressor stations with gas turbine engines as the driver to the gas compressor have been investigated. The selected engines models were developed based on public domain specification, using an in-house engine performance simulation software: TURBOMATCH. Three seasons (rainy, dry and hot seasons) were considered in this paper based on the location of Trans-Saharan gas pipeline being investigated. Compressor and turbine were degraded (fouled) as a single type of degradation producing three performance scenarios (optimistic, medium and pessimistic). These scenarios define the levels of deterioration of the gas turbine in comparison with the clean conditions. The baseline case indicated that at a controlled TET, the number of GT used in each compressor station increases with increase in degradation (reduction in flow capacity and isentropic efficiency) which result to a variation in the number of engines per station. The result revealed that the implementation of rescheduled-overhaul on the engines reduces the number of Gas turbine usage at the same degraded and ambient condition of the baseline case. The further result indicated that the optimistic, medium and pessimistic scenarios that used 99, 106 and 120 number of engines for the 18 compression stations at baseline condition reduces to 91, 104 and 115 respectively when rescheduled overhaul was implemented for the same amount of gas to be delivered and at the same operating conditions. The proposed approach will enhance engine life-extension strategies that engine life-cycle managers, or natural gas pipeline investors may adopt to cost-effectively manage their engines while ensuring reliability and safety on the pipeline business.

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