Bench Scale Experimental Study of Slug Flow Phenomena Using PID Control

2018 ◽  
Author(s):  
Daniel S. Schmidt ◽  
Derek W. Staal ◽  
Jeffery W. McClung ◽  
Mark V. Behl ◽  
Mayank Tyagi
Keyword(s):  
Multiphase Flow ◽  
Flow Regime ◽  
Pid Control ◽  
Slug Flow ◽  
Control Strategies ◽  
Visual Observation ◽  
Gas Production ◽  
High Rate ◽  
Flow Loop ◽  
Bench Scale

Offshore petroleum production operations pose a unique set of challenges. A common undesirable phenomenon that occurs in these multiphase flow systems is known as slug flow. Slug flow is an oscillatory flow regime that creates large bullet shaped bubbles (also known as Taylor Bubbles) followed by large slugs of liquid. This high-rate alternation of liquid and gas production volumes in the surface facilities causes severe pressure oscillations. These oscillations adversely affect the structural health and individual components. A bench-scale closed flow loop was built with capabilities of measuring pressure and flow rates at different relevant sections. PID control strategy to mitigate the harmful effects of slug flow regime showed promise, although the tests were performed in the low pressure conditions of bench scale setup. The sensors and valve were programmed with MATLAB® to provide real time analysis, and a PID controller was utilized to adjust the back pressure. Initial experimental data and visual observation provided better understanding of slug flow regime and some quantitative data was obtained through image processing. Theoretical estimates of Taylor bubble velocities were found to be in agreement with presented observations. Further experiments are being carried out to gather data and showcase this model to develop better multiphase flow control strategies.

Gas Void Fraction Measurement in Two-Phase Gas/Liquid Slug Flow Using Acoustic Emission Technology

2009 ◽  
Vol 131 (6) ◽  
Author(s):  
S. Al-lababidi ◽  
A. Addali ◽  
H. Yeung ◽  
D. Mba ◽  
F. Khan
Keyword(s):  
Acoustic Emission ◽  
Flow Regime ◽  
Void Fraction ◽  
Slug Flow ◽  
Chemical Engineering ◽  
Oil And Gas ◽  
Gas Production ◽  
Engineering Industry ◽  
Two Phase ◽  
Gas Void Fraction

The gas-liquid two-phase slug flow regime phenomenon is commonly encountered in the chemical engineering industry, particularly in oil and gas production transportation pipelines. Slug flow regime normally occurs for a range of pipe inclinations, and gas and liquid flowrates. A pipeline operating in the slug flow regime creates high fluctuations in gas and liquid flowrates at the outlet. Therefore, the monitoring of slugs and the measurement of their characteristics, such as the gas void fraction, are necessary to minimize the disruption of downstream process facilities. In this paper, a correlation between gas void fraction, absolute acoustic emission energy, and slug velocities in a two-phase air/water flow regime was developed using an acoustic emission technique. It is demonstrated that the gas void fraction can be determined by measurement of acoustic emission.

The Effect of Inclination on Flow Regime Boundaries and Slug Flow Characteristics

1989 ◽  
Vol 111 (3) ◽  
pp. 181-186 ◽  
Author(s):  
D. G. Wood
Keyword(s):  
Flow Regime ◽  
Slug Flow ◽  
Oil And Gas ◽  
Production Systems ◽  
Flow Characteristics ◽  
Gas Production ◽  
Research Centre ◽  
Test Rig ◽  
Oil And Gas Production ◽  
Capital Costs

Multiphase schemes for oil and gas production systems are becoming more common as the development of marginal fields necessitates a reduction in capital costs. Prediction of flow regime within these pipelines and the characteristics of the flow, especially within the slugging regime, is required in order to design the pipeline and the downstream separation and processing facilities. Test rig studies have been carried out at BP’s Sunbury Research Centre on the effect of small changes in pipeline inclination on both the flow regime and the characteristics of slug flow. Results from tests on a 2-in. rig are quoted.

A bench-scale flow loop study on hydrate deposition under multiphase flow conditions

Fuel ◽  
2020 ◽  
Vol 262 ◽  
pp. 116558 ◽  
Author(s):  
Xianwei Zhang ◽  
Erlend O. Straume ◽  
Giovanny A. Grasso ◽  
Rigoberto E.M. Morales ◽  
Amadeu K. Sum
Keyword(s):  
Multiphase Flow ◽  
Flow Conditions ◽  
Flow Loop ◽  
Bench Scale ◽  
Hydrate Deposition

scholarly journals Online recognition of the multiphase flow regime and study of slug flow in pipeline

2009 ◽  
Vol 147 ◽  
pp. 012047
Author(s):  
Guo Liejin ◽  
Bai Bofeng ◽  
Zhao Liang ◽  
Wang Xin ◽  
Gu Hanyang
Keyword(s):  
Multiphase Flow ◽  
Flow Regime ◽  
Slug Flow ◽  
Online Recognition

Forces on Bends and T-Joints due to Multiphase Flow

2010 ◽  
Author(s):  
S. P. C. Belfroid ◽  
M. F. Cargnelutti ◽  
W. Schiferli ◽  
Marlies van Osch
Keyword(s):  
Multiphase Flow ◽  
Flow Regime ◽  
Slug Flow ◽  
Annular Flow ◽  
Gas Flow ◽  
Stratified Flow ◽  
Operating Conditions ◽  
Large Radius ◽  
Flow Conditions ◽  
Wide Range

To be able to assess the mechanical integrity of piping structures for loading to multiphase flow conditions, air-water experiments were carried out in a horizontal 1″ pipe system. Forces and accelerations were measured on a number of bends and T-joint configurations for a wide range of operating conditions. Five different configurations were measured: a baseline case consisting of a straight pipe only, a sharp edged bend, a large radius bend, a symmetric T-joint and a T-joint with one of the arms closed off. The gas flow was varied from a superficial velocity of 0.1 to 30 m/s and the liquid flow was varied from 0.05 to 2 m/s. This operating range ensures that the experiment encompasses all possible flow regimes. The magnitude of the measured forces was found to vary over a wide range depending on the flow regime. For slug flow conditions very high force levels were measured, up to 4 orders of magnitude higher than in single phase flow for comparable velocities. The annular flow regime resulted in the (relative) lowest forces, although the absolute amplitude is of the same order as in the case of slug flow. In case of slug flow, the measured results can be described assuming a simple slug unit model. For both the frequency and amplitude the available models can be used in assessments. In annular and stratified flow a different model is required, since no slug unit is present. Instead, the amplitude of the excitation force can be estimated using mixture properties. To predict the main frequency for the annular flow and stratified flow additional experiments are required.

On Instabilities in Horizontal Two-Phase Flow

1994 ◽  
Vol 59 (12) ◽  
pp. 2595-2603
Author(s):  
Lothar Ebner ◽  
Marie Fialová
Keyword(s):  
Differential Equation ◽  
Flow Regime ◽  
Slug Flow ◽  
Annular Flow ◽  
Two Phase Flow ◽  
Phase Flow ◽  
Two Phase ◽  
Annular Flows ◽  
Flow Regime Maps

Two regions of instabilities in horizontal two-phase flow were detected. The first was found in the transition from slug to annular flow, the second between stratified and slug flow. The existence of oscillations between the slug and annular flows can explain the differences in the limitation of the slug flow in flow regime maps proposed by different authors. Coexistence of these two regimes is similar to bistable behaviour of some differential equation solutions.

Multiphase Transient Slugging Flow in Subsea Oil and Gas Production

2016 ◽  
Author(s):  
Zhenhua Zhang ◽  
Longbin Tao
Keyword(s):  
Data Analysis ◽  
Temperature Distribution ◽  
Numerical Model ◽  
Slug Flow ◽  
Field Data ◽  
Oil And Gas ◽  
Gas Production ◽  
Worst Case ◽  
Oil And Gas Production ◽  
Significant Difference

Slug flow in horizontal pipelines and riser systems in deep sea has been proved as one of the challenging flow assurance issues. Large and fluctuating gas/liquid rates can severely reduce production and, in the worst case, shut down, depressurization or damage topside equipment, such as separator, vessels and compressors. Previous studies are primarily based on experimental investigations of fluid properties with air/water as working media in considerably scaled down model pipes, and the results cannot be simply extrapolated to full scale due to the significant difference in Reynolds number and other fluid conditions. In this paper, the focus is on utilizing practical shape of pipe, working conditions and fluid data for simulation and data analysis. The study aims to investigate the transient multiphase slug flow in subsea oil and gas production based on the field data, using numerical model developed by simulator OLGA and data analysis. As the first step, cases with field data have been modelled using OLGA and validated by comparing with the results obtained using PIPESYS in steady state analysis. Then, a numerical model to predict slugging flow characteristics under transient state in pipeline and riser system was set up using multiphase flow simulator OLGA. One of the highlights of the present study is the new transient model developed by OLGA with an added capacity of newly developed thermal model programmed with MATLAB in order to represent the large variable temperature distribution of the riser in deep water condition. The slug characteristics in pipelines and temperature distribution of riser are analyzed under the different temperature gradients along the water depth. Finally, the depressurization during a shut-down and then restart procedure considering hydrate formation checking is simulated. Furthermore, slug length, pressure drop and liquid hold up in the riser are predicted under the realistic field development scenarios.

scholarly journals High risk of relapsed disease in patients with NK/T cell chronic active Epstein-Barr virus disease outside of Asia

2021 ◽  
Author(s):  
Blachy J Dávila Saldaña ◽  
Tami D John ◽  
Challice L Bonifant ◽  
David Buchbinder ◽  
Sharat Chandra ◽  
...  
Keyword(s):  
Epstein Barr Virus ◽  
Virus Disease ◽  
Control Strategies ◽  
The United States ◽  
High Rate ◽  
Hematopoietic Stem ◽  
Curative Therapy ◽  
Barr Virus ◽  
Epstein Barr ◽  
Relapsed Disease

Chronic active Epstein-Barr virus (EBV) disease (CAEBV) is characterized by high levels of EBV predominantly in T and/or NK cells with lymphoproliferation, organ failure due to infiltration of tissues with virus-infected cells, hemophagocytic lymphohistiocytosis (HLH) and/or lymphoma. The disease is more common in Asia than in the United States and Europe. While allogeneic hematopoietic stem cell transplantation (HSCT) is considered the only curative therapy for CAEBV, its efficacy and the best treatment modality to reduce disease severity prior to HSCT is unknown. Here, we retrospectively assessed an international cohort of 57 patients outside of Asia. Treatment for the disease varied widely, although most patients ultimately proceeded to HSCT. Though patients undergoing HSCT had better survival than those who did not (55% v 25%, p<0.01), there was still a high rate of death in both groups. Mortality was largely not affected by age, ethnicity, cell type involvement, or disease complications, but development of lymphoma showed a trend with increased mortality (56% v 35%, p=0.1). The overwhelming majority (75%) of patients who died after HSCT succumbed to relapsed disease. CAEBV remains challenging to treat when advanced disease is present. Outcomes would likely improve with better disease control strategies, earlier referral for HSCT, and close follow-up after HSCT including aggressive management of rising EBV DNA levels in the blood.

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