Online Closed Loop Pipeline Control by Transient Computer Model

1996 ◽  
Author(s):  
Ruprecht M. J. Pichler
Keyword(s):  
New Technology ◽  
Maximum Flow ◽  
Operating Conditions ◽  
Pipeline System ◽  
Maximum Throughput ◽  
Worst Case ◽  
On Line ◽  
Pump Stations ◽  
Fail Safe ◽  
Case Condition

Pipelines transporting different grades of crude oil or products usually operate with fixed setpoints for pressure limit switches and relief valves. These setpoints are calculated for a worst case condition as maximum flow rate combined with a sequence of batches of high viscosity ratio, etc. Under standard operating conditions, this worst case condition never occurs, so the setpoints restrict operating flexibility. With a transient simulation model it is possible to calculate these setpoints for actual hydraulic conditions on-line. Special attention has been paid to fail-safe operation of this on-line model and setpoint calculation. Our approach avoids all the problems linked to software in fail-safe applications and may be used for other applications of on-line simulation too. This concept has been successfully applied to a pipeline system in Austria, the AWP-Pipeline. With the new technology, substantial savings in energy costs (1–2 pump stations out of 11) as well as increased maximum throughput are possible now.

Avoidance of Slack Flow in Liquid Pipelines

2004 ◽  
Author(s):  
Te Ma ◽  
Oliver O. Youzwishen ◽  
Michael Hylton
Keyword(s):  
Detection System ◽  
Pressure Head ◽  
Pressure Control ◽  
Leak Detection ◽  
Operating Conditions ◽  
Pipeline System ◽  
Hydraulic Analysis ◽  
Valley Bottom ◽  
Effective Manner ◽  
Pump Stations

There are many existing liquid transmission pipelines that have significant changes in elevation along their route, making them susceptible to operating at “slack flow” conditions. Slack flow occurs in a pipeline when the pipeline pressure falls below the vapor pressure of that liquid (i.e. the pressure head decreases below the elevation at a certain point and causes the gauge pressure at that point to drop below zero atmosphere). Separation of the fluid column occurs, which can result in leak detection system inaccuracy and poor pressure/flow control during pigging operations. The designs of older pipelines typically did not address the slack flow issue. In order to eliminate the occurrence of slack flow, some method of pressure control is necessary, such as the installation of a pressure regulator station (PRS). In this paper a case study is used to demonstrate how a detailed hydraulic analysis was utilized in the design of an effective PRS, to eliminate slack flow. The subject pipeline system was approximately 800 km in length; with six pump stations and one terminal tank farm. One section of the pipeline contained an elevation difference of more than 1000 m (between mountain top and river valley bottom), creating slack flow operating conditions. A decision was made by the pipeline operator to prevent (potential) over pressurization at the lowest point on the pipeline. A secondary goal was to upgrade the leak detection system by eradicating the slack flow operation. Designing and installing a PRS and an over-pressure safety valve station achieved both of these goals. The PRS design, operation philosophy and safety philosophy development utilized information derived from a transient hydraulic simulation of the pipeline, using a hydraulic pipeline simulator (HPS). By using transient hydraulic analysis, an optimized solution to slack flow and over-pressuring on a liquids pipeline with large elevation differences, was achieved. By installing a PRS in an optimized location the pipeline operator has increased the reliability of leak detection and reduced the risks of over-pressuring, in a safe, cost effective manner.

Validation of On-line Respiration Meter and its Applications by Computer Simulation

1992 ◽  
Vol 26 (5-6) ◽  
pp. 1355-1363 ◽  
Author(s):  
C-W. Kim ◽  
H. Spanjers ◽  
A. Klapwijk
Keyword(s):  
Steady State ◽  
Activated Sludge ◽  
Respiration Rate ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Mass Balances ◽  
Short Term ◽  
Respiration Rates ◽  
On Line ◽  
Made In

An on-line respiration meter is presented to monitor three types of respiration rates of activated sludge and to calculate effluent and influent short term biochemical oxygen demand (BODst) in the continuous activated sludge process. This work is to verify if the calculated BODst is reliable and the assumptions made in the course of developing the proposed procedure were acceptable. A mathematical model and a dynamic simulation program are written for an activated sludge model plant along with the respiration meter based on mass balances of BODst and DO. The simulation results show that the three types of respiration rate reach steady state within 15 minutes under reasonable operating conditions. As long as the respiration rate reaches steady state the proposed procedure calculates the respiration rate that is equal to the simulated. Under constant and dynamic BODst loading, the proposed procedure is capable of calculating the effluent and influent BODst with reasonable accuracy.

scholarly journals Treatment of fish processing industry wastewater using hydrodynamic cavitational reactor with biodegradability improvement

2019 ◽  
Vol 80 (12) ◽  
pp. 2310-2319 ◽  
Author(s):  
Prashant Dhanke ◽  
Sameer Wagh ◽  
Abhijeet Patil
Keyword(s):  
Organic Matter ◽  
New Technology ◽  
Oxygen Demand ◽  
Operating Conditions ◽  
Hydrodynamic Cavitation ◽  
Inlet Pressure ◽  
Fish Processing ◽  
Processing Industry ◽  
Cavitation Effect ◽  
Processing Plants

Abstract Water generated from the fish processing industry is contaminated with organic matter. This organic matter present in wastewater increases the biochemical oxygen demand (BOD) and chemical oxygen demand (COD). A new technology, hydrodynamic cavitation (HC) is used to deal with this wastewater produced in fish processing plants. The orifice plate is used in the HC reactor to generate a cavitation effect. The intensification of this technique was carried out with the help of hydrogen peroxide (H2O2) and TiO2. The treatment of this wastewater is reported in terms of percent degradation in BOD and COD and in biodegradability index (BI). Operating parameters like inlet pressure, pH, operating temperature and H2O2 doses were used to find the optimum condition. 15 g/L of H2O2 gave 69.5% reduction of COD in the 120 min of treatment that also increases BI value to 0.93 at inlet pressure 8 bar, Plate-5, temperature (30 °C), and pH 4. In the ultrasonic cavitation (UC) reactor, COD reduction is 68.7% without TiO2 and with TiO2 it is 71.2%. Also, this HC and UC reactor reduced CFU count to a great extent at the same operating conditions.

scholarly journals Optimal Tuner Selection for Kalman Filter-Based Aircraft Engine Performance Estimation

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Donald L. Simon ◽  
Sanjay Garg
Keyword(s):  
Kalman Filter ◽  
Estimation Error ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Operating Conditions ◽  
Performance Estimation ◽  
Experimental Simulation ◽  
Tuning Parameter ◽  
Estimation Accuracy ◽  
On Line

A linear point design methodology for minimizing the error in on-line Kalman filter-based aircraft engine performance estimation applications is presented. This technique specifically addresses the underdetermined estimation problem, where there are more unknown parameters than available sensor measurements. A systematic approach is applied to produce a model tuning parameter vector of appropriate dimension to enable estimation by a Kalman filter, while minimizing the estimation error in the parameters of interest. Tuning parameter selection is performed using a multivariable iterative search routine that seeks to minimize the theoretical mean-squared estimation error. This paper derives theoretical Kalman filter estimation error bias and variance values at steady-state operating conditions, and presents the tuner selection routine applied to minimize these values. Results from the application of the technique to an aircraft engine simulation are presented and compared with the conventional approach of tuner selection. Experimental simulation results are found to be in agreement with theoretical predictions. The new methodology is shown to yield a significant improvement in on-line engine performance estimation accuracy.

Pressure Cycling Monitoring Helps Ensure the Integrity of Energy Pipelines

2010 ◽  
Author(s):  
Peter Song ◽  
Doug Lawrence ◽  
Sean Keane ◽  
Scott Ironside ◽  
Aaron Sutton
Keyword(s):  
Fatigue Life ◽  
Pipeline System ◽  
Outer Diameter ◽  
Operating Pressure ◽  
Potential Growth ◽  
Integrity Assessment ◽  
Pressure Cycling ◽  
Pressure Cycle ◽  
Primary Focus ◽  
Pump Stations

Liquids pipelines undergo pressure cycling as part of normal operations. The source of these fluctuations can be complex, but can include line start-stop during normal pipeline operations, batch pigs by-passing pump stations, product injection or delivery, and unexpected line shut-down events. One of the factors that govern potential growth of flaws by pressure cycle induced fatigue is operational pressure cycles. The severity of these pressure cycles can affect both the need and timing for an integrity assessment. A Pressure Cycling Monitoring (PCM) program was initiated at Enbridge Pipelines Inc. (Enbridge) to monitor the Pressure Cycling Severity (PCS) change with time during line operations. The PCM program has many purposes, but primary focus is to ensure the continued validity of the integrity assessment interval and for early identification of notable changes in operations resulting in fatigue damage. In conducting the PCM program, an estimated fatigue life based on one month or one quarter period of operations is plotted on the PCM graph. The estimated fatigue life is obtained by conducting fatigue analysis using Paris Law equation, a flaw with dimensions proportional to the pipe wall thickness and the outer diameter, and the operating pressure data queried from Enbridge SCADA system. This standardized estimated fatigue life calculation is a measure of the PCS. Trends in PCS overtime can potentially indicate the crack threat susceptibility the integrity assessment interval should be updated. Two examples observed on pipeline segments within Enbridge pipeline system are provided that show the PCS change over time. Conclusions are drawn for the PCM program thereafter.

Efficient Analysis of a Catenary Riser

2006 ◽  
Author(s):  
Elizabeth Passano ◽  
Carl M. Larsen
Keyword(s):  
Operating Conditions ◽  
Stochastic Simulations ◽  
Worst Case ◽  
Nonlinear Structure ◽  
Tension Response ◽  
Extreme Response ◽  
Analysis Strategies ◽  
Low Tension ◽  
Term Response

The paper deals with the challenge of predicting the extreme response of catenary risers, a topic of both industry and academic interest. Large heave motions introduced at the upper end of a catenary riser can lead to compression and large bending moments in the region immediately above the touch down area. In the worst case, dynamic beam buckling may occur. The focus of the paper will be on understanding the riser behaviour in extreme, low-tension response and in establishing suitable analysis strategies to predict the extreme response. Results from long nonlinear stochastic simulations of many sea states with varying environmental and operating conditions may be combined to describe the long-term response of a nonlinear structure such as a catenary riser. However, this theoretically straight-forward approach is very demanding computationally and ways to limit the extent of nonlinear stochastic simulations are therefore sought. The usefulness of simpler methods such as regular wave analysis to improve understanding of the physical behaviour and to aid in concentrating the nonlinear simulations to where they are most useful, will be demonstrated.

Quantitative Risk Analysis and Comparison for Onshore and Offshore LNG Terminals: The Port of Suape - Brazil Case

2011 ◽  
Author(s):  
Marilia A. Ramos ◽  
Enrique L. Droguett ◽  
Marcelo R. Martins ◽  
Henrique P. Souza
Keyword(s):  
Natural Gas ◽  
Original Form ◽  
Pipeline System ◽  
Industrial Complex ◽  
Flammability Limits ◽  
Liquid Form ◽  
Worst Case ◽  
Final Destination ◽  
Natural Gas Pipeline ◽  
Vapor Cloud

In recent decades, natural gas has been gaining importance in world energy scene and established itself as an important source of energy. One of the biggest obstacles to increase the usage of natural gas is its transportation, mostly done in its liquid form, LNG – Liquefied Natural Gas, and storage. It involves the liquefaction of natural gas, transport by ship, its storage and subsequent regasification, in order to get natural gas in its original form and send it to the final destination through natural gas pipeline system. Nowadays, most terminals for receiving, storing and regasificating LNG, as well as sending-out natural gas are built onshore. These terminals, however, are normally built close to populated areas, where consuming centers can be found, creating safety risks to the population nearby. Apart from possible damages caused by its cryogenic temperatures, LNG spills are associated with hazards such as pool fires and ignition of drifting vapor clouds. Alternatively to onshore terminals, there are currently several offshore terminals projects in the world and some are already running. Today, Brazil owns two FSRU (Floating Storage and Regasification Unit) type offshore terminals, one in Guanabara Bay, Rio de Janeiro and the other in Pece´m, Ceara´, both contracted to PETROBRAS. The identification of the operation risks sources of LNG terminals onshore and offshore and its quantification through mathematical models can identify the most suitable terminal type for a particular location. In order to identify and compare the risks suggested by onshore and offshore LNG terminals, we have taken the example of the Suape Port and its Industrial Complex, located in Pernambuco, Brazil, which is a promising location for the installation of a LNG terminal. The present work has focused on calculating the distance to the LNG vapor cloud with the lower flammability limits (LFL), as well as thermal radiation emitted by pool fire, in case of a LNG spill from an onshore and from an offshore terminal. The calculation was made for both day and night periods, and for three types of events: operational accident, non-operational accident and worst case event, corresponding to a hole size of 0,75m, 1,5m e 5m, respectively. Even though the accidents that happen at an onshore terminal generate smaller vulnerability distances, according to the results it would not be desirable for the Suape Port, due to the location high density of industries and people working. Therefore, an offshore terminal would be more desirable, since it presents less risk to the surrounding populations, as well as for workers in this location.

Risk Assessment for Small Diameter Piping for Liquid Pipeline Facilities

2018 ◽  
Author(s):  
C. M. Refaul Ferdous ◽  
Amanda Kulhawy ◽  
Jessica Farrell ◽  
Chris Beaudin ◽  
Anthony Payoe ◽  
...  
Keyword(s):  
Risk Measure ◽  
Small Diameter ◽  
Pipeline System ◽  
System Description ◽  
Maintenance Program ◽  
Inspection And Maintenance ◽  
Pressure Transmitter ◽  
Integrity Risk ◽  
Main Station ◽  
Pump Stations

The Enbridge Liquids Pipeline system is comprised of a large number of facilities including storage terminals, pump stations, injection sites, and delivery sites. Given the vast amount of small diameter piping (SDP) within company Pipeline facilities, SDP represents a significant portion of total facility integrity risk. An event such as equipment failure or product release can cause significant business impacts, and adverse consequences to the environment and/or safety of operations personnel. A quantitative risk based approach is required in order to establish robust, risk-based plans and programs to maintain the integrity of these SDP sections. Small diameter piping lengths are relatively short. Consequently, it is impractical to use SDP length as a unit of likelihood and risk measure. Instead, the preferred methodology is to determine the total number of assemblies for each type of SDP. In support of this approach, an inventory of SDP sections throughout the system has been gathered. For illustrative purposes, an example of a small diameter section would be a pressure transmitter branch connection. The isolatable section that would be risk assessed would start from the surface of the main station piping connection and continue up to the transmitter. This paper presents the framework for likelihood and consequence assessment of SDP based on the system description above. This framework quantitatively estimates the risk of SDP failure and risk-ranks SDP sections in support of implementing and establishing a system wide Risk Based Inspection and Maintenance program for SDP.

Avoiding Sedimentation and Air Entrainment in Pump Sump for Wet Pit Pumping Stations

2015 ◽  
Author(s):  
Raja Abou Ackl ◽  
Andreas Swienty ◽  
Flemming Lykholt-Ustrup ◽  
Paul Uwe Thamsen
Keyword(s):  
Physical Model ◽  
Air Entrainment ◽  
Flow Patterns ◽  
Operating Conditions ◽  
Design Criteria ◽  
Flow Conditions ◽  
Pumping Station ◽  
Pumping Stations ◽  
Pump Sump ◽  
Pump Stations

In many places lifting systems represent central components of wastewater systems. Pumping stations with a circular wet-pit design are characterized by their relatively small footprint for a given sump volume as well as their relatively simple construction technique [1]. This kind of pumping stations is equipped with submersible pumps. These are located in this case directly in the wastewater collection pit. The waste water passes through the pump station untreated and loaded with all kind of solids. Thus, the role of the pump sump is to provide an optimal operating environment for the pumps in addition to the transportation of sewage solids. Understanding the effects of design criteria on pumping station performance is important to fulfil the wastewater transportation as maintenance-free and energy efficient as possible. The design of the pit may affect the overall performance of the station in terms of poor flow conditions inside the pit, non-uniform und disturbed inflow at the pump inlet, as well as air entrainment to the pump. The scope of this paper is to evaluate the impact of various design criteria and the operating conditions on the performance of pump stations concerning the air entrainment to the pump as well as the sedimentation inside the pit. This is done to provide documentation and recommendations of the design and operating of the station. The investigated criteria are: the inflow direction, and the operating submergence. In this context experiments were conducted on a physical model of duplex circular wet pit wastewater pumping station. Furthermore the same experiments were reproduced by numerical simulations. The physical model made of acrylic allowed to visualize the flow patterns inside the sump at various operating conditions. This model is equipped with five different inflow directions, two of them are tangential to the pit and the remaining three are radial in various positions relative to the pumps centerline. Particles were used to enable the investigation of the flow patterns inside the pit to determine the zones of high sedimentation risk. The air entrainment was evaluated on the model test rig by measuring the depth, the width and the length of the aerated region caused by the plunging water jet and by observing the air bubbles entering the pumps. The starting sump geometry called baseline geometry is simply a flat floor. The tests were done at all the possible combinations of inflow directions, submergence, working pump and operating flow. The ability of the numerical simulation to give a reliable prediction of air entrainment was assessed to be used in the future as a tool in scale series to define the scale effect as well as to analyze the flow conditions inside the sump and to understand the air entrainment phenomenon. These simulations were conducted using the geometries of the test setup after generating the mesh with tetrahedral elements. The VOF multiphase model was applied to simulate the interaction of the liquid water phase and the gaseous air phase. On the basis of the results constructive suggestions are derived for the design of the pit, as well as the operating conditions of the pumping station. At the end recommendations for the design and operating conditions are provided.

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