scholarly journals Protecting a Pumping Pipeline System from Low Pressure Transients by Using Air Pockets: A Case Study

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1786 ◽  
Author(s):  
Rafael Bernardo Carmona-Paredes ◽  
Oscar Pozos-Estrada ◽  
Libia Georgina Carmona-Paredes ◽  
Alejandro Sánchez-Huerta ◽  
Eduardo Antonio Rodal-Canales ◽  
...  
Keyword(s):  
Design Stage ◽  
Pipeline System ◽  
Pressure Waves ◽  
Transient Pressure ◽  
Transient Simulations ◽  
Transient Control ◽  
Water Pipeline ◽  
Potential Damage ◽  
Air Pockets

This paper presents a case study of an existing water pipeline with five pumping stations each equipped with five pumps. In order to study the pipeline behavior prior to putting the system into operation, several transient simulations for different scenarios were developed. Results revealed that the most serious situation occurred when a simultaneous failure of the five pumps occur at each station caused by power cut, producing negative pressure waves because the system for control of hydraulic transients of the pipeline was insufficient to suppress downsurge pressures, due to the moment of inertia of all the pumps being erroneously considered during the design stage. The necessity to start supplying water to the population led to attempt an unconventional form of protecting the line against low pressures. The solution was to operate two of the five pumps per plant, and permit air to enter through combination air valves located along the pipeline. Air entrained formed pockets that remained stationary at the air valves locations, acting as air cushions that absorbed the energy of transient pressure waves. Computational simulations were conducted considering that two pumps are in operation at each plant and suddenly these fail simultaneously caused by power failure. The program was verified by comparing the calculated results with those registered during field pressure measurements. It was noticed that the surge modelling results are in good agreement with the measured data; furthermore, these show the air pockets in combination with existing devices for transient control protect the system adequately, avoiding potential damage to the pipeline.

scholarly journals Electrolytic corrosion of water pipeline system in the remote distance from stray currents—Case study

2016 ◽  
Vol 4 ◽  
pp. 116-124 ◽  
Author(s):  
Krzysztof Zakowski​ ◽  
Kazimierz Darowicki​ ◽  
Juliusz Orlikowski​ ◽  
Agata Jazdzewska​ ◽  
Stefan Krakowiak​ ◽  
...  
Keyword(s):  
Pipeline System ◽  
Electrolytic Corrosion ◽  
Water Pipeline

Case Study: Mardi Gras Deep Water Transportation System GIS and Underwater Inspections

2006 ◽  
Author(s):  
W. Leith McDonald ◽  
Gordon Gin ◽  
Rachel Boyle
Keyword(s):  
Deep Water ◽  
New Technology ◽  
Large Diameter ◽  
Transportation System ◽  
Pipeline System ◽  
Management Tools ◽  
Mardi Gras ◽  
Water Transportation ◽  
Water Pipeline

This paper presents a case study of BP’s Mardi Gras Gulf of Mexico deep water pipeline transportation system. The Mardi Gras Transportation System (MGTS), operated by BP Pipelines, N.A. has set the standard for large diameter, deepwater pipeline design, construction and maintenance. The pipelines range in size from NPS 16 to NPS 30 in water depths up to 7,300 ft. The paper showcases the ArcGIS and PODS relational database management tools and the process of how we implemented programs to track underwater facility features and their displacements caused by the 2005 hurricane season. We will describe the challenges, solutions and new technology used to monitor and maintain the integrity of this pipeline system, even when covered by 5000 feet or more of water. Submarine (ROV) inspection technology, digital video and GPS are the order of the day. We shall demonstrate how GIS can assist in managing and reporting the results of the inspections and setup a database for long term managment of the pipeline system.

Transient Impact of Valve Closure Times: Disagreements Between Design and Application

2017 ◽  
Author(s):  
Ilker T. Telci ◽  
Shesh R. Koirala
Keyword(s):  
Transient Analysis ◽  
Lag Time ◽  
Field Conditions ◽  
Dynamic Loads ◽  
Design Stage ◽  
Pressure Waves ◽  
Valve Closure ◽  
Pipe Network ◽  
Transient Pressure ◽  
Transient Event

Many pressurized liquid systems require emergency shut down procedures in order to prevent damage to the piping and components, environmental contamination and fire hazard. The emergency shutdowns (ESDs) are facilitated by fast closing on-off valves installed at various locations along the piping system. When these valves close they create transient pressure waves traveling through the pipe network. These waves can be reflected at the dead-ends or closed valves. At locations where the pressure decreases below the vapor pressure, liquid column separation followed by a rejoining can cause creation of new transient pressure waves. As these waves travel, they may meet and superpose. These complex surge pressure wave behaviors require modeling of the pipe network and simulation of the transient event as the first step of a transient analysis. The second step of the transient analysis is to pin point the problems such as excessive surge pressures and dynamic loads that may occur in the system. The third step is to provide recommendations to prevent undesired transient consequences. One of the most important components of these recommendations include valve closure times during ESDs. Recent field measurements on the valve closure rates showed that the valve closure times recommended by the transient analysis were not accurately implemented. One reason for this disagreement between the designed closure rates and the applied closure rates is that the actuators of the valves introduce a time lag between the shutdown signal and start of valve closure. Another reason comes from the decision taken by the operator adjusting the actuator timing. Some operators may adjust the actuators such that the valves close within the prescribed time including the lag time which may result in very fast valve closures depending on the lag of the actuators. Other operators may choose to close the valves within the prescribed time including the lag time or even slower than the recommended rates. This may impair the orchestrate of the valve closure events designed in the transient analysis resulting in excessive surge pressures or dynamic loads. This study investigates (i) the discrepancies between the recommendations from transient study made early in the design stage and (ii) the transient impact due to the deviation and/or misinterpretation of those recommendations. Specifically, in this study, these problems are demonstrated in a case study from LNG - Ship loading systems. The results indicated that transient analysis is the essential tool in finding critical components of the system in the field conditions providing a variety of solutions such as valve closure rate adjustments, flow rate reduction at the beginning of ESDs via pump trips and pipe size increase at dead legs. This study showed that the pressure piping systems can deviate from initial design under dynamic field conditions and frequent inspections of the ESD valves are crucial for safe operations of these systems.

scholarly journals Detection and sizing of extended partial blockages in pipelines by means of a stochastic successive linear estimator

2013 ◽  
Vol 16 (2) ◽  
pp. 248-258 ◽  
Author(s):  
Christian Massari ◽  
Tian Chyi J. Yeh ◽  
Marco Ferrante ◽  
Bruno Brunone ◽  
Silvia Meniconi
Keyword(s):  
Water System ◽  
Diameter Distribution ◽  
Linear Estimator ◽  
System Management ◽  
Pipeline System ◽  
Theoretical Formulation ◽  
Current State ◽  
Water Pipeline ◽  
Numerical Case Study

Effective water system management depends upon knowledge of the current state of a water pipeline system network. For example, in many cases, partial blockages in a water pipeline system are a source of inefficiencies, and result in an increase of pumping costs. These anomalies must be detected and corrected as early as possible. In this study, an algorithm is developed for detecting blockages by means of pressure transient measurements and estimating the diameter distribution resulting from their formation. The algorithm is a stochastic successive linear estimator that provides statistically the best unbiased estimate of diameter distribution due to partial blockages and quantifies the uncertainty associated with these estimates. We first present the theoretical formulation of the algorithm and then test it with a numerical case study.

scholarly journals Preventing Dampness Related Health Risks at the Design Stage of Buildings in Mediterranean Climates: A Cyprus Case Study

Buildings ◽  
2018 ◽  
Vol 8 (5) ◽  
pp. 66
Author(s):  
Ugochukwu Elinwa ◽  
Cemil Atakara ◽  
Ifeoluwa Ojelabi ◽  
Abiola Abiodun
Keyword(s):  
Health Risks ◽  
Design Stage

Method for Redesign of District Heating Networks within Transition from the 2nd to the 3rd Generation

2014 ◽  
Vol 657 ◽  
pp. 689-693
Author(s):  
Răzvan Corneliu Lefter ◽  
Daniela Popescu ◽  
Alexandrina Untăroiu
Keyword(s):  
District Heating ◽  
Design Stage ◽  
Heating Systems ◽  
Load Duration ◽  
Load Duration Curve ◽  
District Heating Systems ◽  
Consumption Rates ◽  
Heat Loads ◽  
Heating Networks

Important investmentsare made lately in the area of district heating, as a technology capable ofhelping countries to reach sustainability goals. In Romania, European fundswere spent for transition from the 2nd to the 3rdgeneration of district heating systems. The lack of appropriate monitoringsystems in old district heating systems makes optimisation nowadays very difficult,especially because nominal values used in the first design stage areoverestimated. Realistic nominal heat loads are necessary to make goodestimations of hydraulic parameters to be used for redesign. This studyproposes a method that uses the heat load duration curve theory to identify theappropriate nominal heat loads to be used for redesign. Comparison betweenresults obtained by applying the nominal heat loads of each consumer, as theywere established in the first design stage, and the ones identified by theproposed method are analyzed in a case study. The results show that errors arein the +/- 3% band, between the metered heat consumption rates and the proposedrates. The new method can be used for the sizing of pumps and district heatingnetworks after retrofit, in order to get better adjustments of the circulationpumps and increase of the energy efficiency.

Assessment of Potential Damage Factor: A Case Study of St. Paul’s Cathedral, Kolkata

2021 ◽  
Vol 6 (1) ◽  
pp. 53-68
Author(s):  
Chiradeep Basu ◽  
Subarna Bhattacharyya ◽  
Anirban Chaudhuri ◽  
Shaheen Akhtar ◽  
Akash Chatterjee ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Nitrogen Concentration ◽  
Building Design ◽  
Airborne Microorganisms ◽  
Air Movement ◽  
Fungal Load ◽  
Heritage Building ◽  
Central Pollution Control Board ◽  
Potential Damage

Damaging factors such as airborne microorganisms, relative humidity, ventilation, temperature and air pollutants are the major concerns of the tropical climate of Kolkata, India where our study site, 172-year-old St. Paul’s Cathedral is located. In this context, the aim was to develop an equation to assess the management priority and which factors would be more responsible for potentially damaging the heritage building. The temperature varied from 28°C to 31°C, relative humidity was recorded 72% over a period of 14 days in the prayer hall whereas almost constant temperature (27°C) and relative humidity (55%) were recorded in crypt. Air movement was recorded 0.5–3 m s−1 in both crypt and prayer hall. Sulphur dioxide and oxide of nitrogen concentration were lower than the standard mentioned by the Central Pollution Control Board, India. The fungal load was lower inside the crypt (237 CFU m−3) than in the prayer hall (793 CFU m−3). Calculated potential damage for prayer hall and crypt was found to be 48.75% and 37.08%, respectively. Results revealed that microbial load and relative humidity were the potent factors for damage to the building. Continuous air movement, that is, ventilation and building design here played significant roles. The Heritage Conservation Committee can use the data for better management.

Study on the impacts of peaking factors on a water distribution system in Germany

2010 ◽  
Vol 10 (2) ◽  
pp. 165-172 ◽  
Author(s):  
K. Diao ◽  
M. Barjenbruch ◽  
U. Bracklow
Keyword(s):  
Energy Consumption ◽  
Distribution System ◽  
Water Distribution ◽  
Water Distribution System ◽  
Water Distribution Network ◽  
Design Stage ◽  
Water Age ◽  
Specific System ◽  
Average Water

This paper aims to explore the impacts of peaking factors on a water distribution system designed for a small city in Germany through model-based analysis. As a case study, the water distribution network was modelled by EPANET and then two specific studies were carried out. The first study tested corresponding system-wide influences on water age and energy consumption if the peaking factors used at design stage are inconsistent with ones in real situation. The second study inspected the possible relationship between the choice of peaking factors and budgets by comparing several different pipe configurations of the distribution system, obtained according to variety of peaking factors. Given the analysis results, the first study reveals that average water age will increase if peaking factors estimated at design stage are larger than real values in that specific system, and vice versa. In contrast, energy consumption will increase if peaking factors defined for system design are smaller than ones in real case, and vice versa. According to the second study, it might be possible to amplify peaking factors for design dramatically by a slight increase in the investment on this system. However, further study on budget estimation with more factors and detailed information considered should be carried out.

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