This document discusses optimizing maintenance of subsea processing systems to maximize oil and gas production. Condition-based maintenance is proposed to replace equipment like pumps and compressors before failure based on monitored degradation. Replacing equipment just before failure could save millions per year compared to running until failure or fixed interval replacement. The document provides a simplified cost analysis comparing the strategies and outlines how condition monitoring could provide advanced warning of failures for some degradation mechanisms.
Aiming better gsm controls a possible approachDevesh Singhal
The document discusses improving control of grammage (GSM) in paper machines by modifying the approach flow system. Currently, variations in GSM occur when the secondary screen reject valve opens only briefly. The document proposes removing the secondary screen and installing a screw pump with a variable frequency drive-controlled motor after the main screen to continuously throttle the reject flow at a low level. This proposed system could eliminate GSM variations and fluctuations in the cross-machine profile while also providing energy savings by removing the secondary screen and reducing throughput needs.
The document discusses the societal impacts of a potential future human mission to Mars. It first outlines existing challenges for such a mission and then identifies various stakeholder groups that influence public opinion, such as governments, space agencies, companies, scientists, media, and taxpayers. A stakeholder matrix is presented that analyzes each group's interest and potential concerns regarding a Mars mission. The document concludes that managing public information and involving diverse international partners will be important to generate support for undertaking the complex endeavor of sending humans to Mars.
Cave habitation on Mars could enable an initial human settlement by providing natural protection from radiation and hazards in the Martian environment. The document discusses assessing cave habitation by analyzing the feasibility, engineering challenges, social impacts, and international cooperation required. It suggests lava tubes could serve as shelters, with stable temperatures and low radiation levels inside. Remote sensing would first need to detect caves to identify potential sites, before robotic and human missions could explore the caves in more detail.
This document summarizes an automotive technicians' professional development forum that will take place from October 20-21, 2016 in Coventry, UK. The forum will provide opportunities for technicians to advance their technical skills and career progression through industry presentations, site visits, workshops, and networking. Key speakers will discuss topics like career paths, changing skill requirements, and future challenges in automotive engineering. The event aims to help technicians gain expertise, expand their industry knowledge, and develop professional networks.
Cornerstone provides a corporate overview and highlights of its first quarter 2016 performance. It discusses its evolution over the past 16 years from a smaller startup to a global leader in talent management solutions. Cornerstone has grown significantly in terms of revenue, clients, users, and geographic reach. It also discusses opportunities for continued growth through further penetrating its existing client base, expanding into new markets and industry verticals, and developing new solutions. Cornerstone's vision is to continue innovating and reach $1 billion in revenue by leveraging its massive talent data and open platform approach.
This document provides information about the "BRAKES 2016: Enhancing Brake Performance and the Integration of New Technologies" seminar organized by NEC, Birmingham UK on November 3rd, 2016. The seminar will focus on the latest developments in brake systems and technologies across the automotive industry. Key speakers will discuss advanced braking systems and strategies from companies like Jaguar Land Rover, Honda, McLaren Automotive and Bentley. The seminar programme will also include sessions on topics like brake pedal feel, regenerative braking, autonomous emergency braking systems, brake noise modeling and challenges. Attendees will have the opportunity to participate in roundtable discussions.
Aiming better gsm controls a possible approachDevesh Singhal
The document discusses improving control of grammage (GSM) in paper machines by modifying the approach flow system. Currently, variations in GSM occur when the secondary screen reject valve opens only briefly. The document proposes removing the secondary screen and installing a screw pump with a variable frequency drive-controlled motor after the main screen to continuously throttle the reject flow at a low level. This proposed system could eliminate GSM variations and fluctuations in the cross-machine profile while also providing energy savings by removing the secondary screen and reducing throughput needs.
The document discusses the societal impacts of a potential future human mission to Mars. It first outlines existing challenges for such a mission and then identifies various stakeholder groups that influence public opinion, such as governments, space agencies, companies, scientists, media, and taxpayers. A stakeholder matrix is presented that analyzes each group's interest and potential concerns regarding a Mars mission. The document concludes that managing public information and involving diverse international partners will be important to generate support for undertaking the complex endeavor of sending humans to Mars.
Cave habitation on Mars could enable an initial human settlement by providing natural protection from radiation and hazards in the Martian environment. The document discusses assessing cave habitation by analyzing the feasibility, engineering challenges, social impacts, and international cooperation required. It suggests lava tubes could serve as shelters, with stable temperatures and low radiation levels inside. Remote sensing would first need to detect caves to identify potential sites, before robotic and human missions could explore the caves in more detail.
This document summarizes an automotive technicians' professional development forum that will take place from October 20-21, 2016 in Coventry, UK. The forum will provide opportunities for technicians to advance their technical skills and career progression through industry presentations, site visits, workshops, and networking. Key speakers will discuss topics like career paths, changing skill requirements, and future challenges in automotive engineering. The event aims to help technicians gain expertise, expand their industry knowledge, and develop professional networks.
Cornerstone provides a corporate overview and highlights of its first quarter 2016 performance. It discusses its evolution over the past 16 years from a smaller startup to a global leader in talent management solutions. Cornerstone has grown significantly in terms of revenue, clients, users, and geographic reach. It also discusses opportunities for continued growth through further penetrating its existing client base, expanding into new markets and industry verticals, and developing new solutions. Cornerstone's vision is to continue innovating and reach $1 billion in revenue by leveraging its massive talent data and open platform approach.
This document provides information about the "BRAKES 2016: Enhancing Brake Performance and the Integration of New Technologies" seminar organized by NEC, Birmingham UK on November 3rd, 2016. The seminar will focus on the latest developments in brake systems and technologies across the automotive industry. Key speakers will discuss advanced braking systems and strategies from companies like Jaguar Land Rover, Honda, McLaren Automotive and Bentley. The seminar programme will also include sessions on topics like brake pedal feel, regenerative braking, autonomous emergency braking systems, brake noise modeling and challenges. Attendees will have the opportunity to participate in roundtable discussions.
This document advertises and provides an agenda for the "International EV Batteries 2016" conference on cost-effective engineering for hybrid and electric vehicles. The two-day conference will showcase innovations automotive companies are making to increase battery range, performance, safety and durability. It will feature speakers from companies like General Motors, Jaguar Land Rover, and McLaren discussing topics like battery pack design, testing, and lifecycle management. The conference aims to address challenges in developing electric vehicles and bringing stakeholders together to share solutions.
Eugene David Lockett is a qualified welder seeking a position in project management. He has over 25 years of experience managing electrical and instrumentation projects in various industries including oil & gas, mining, and petrochemical. His most recent roles include serving as site manager for Sasol projects with Stefanutti Stocks and Grinaker-LTA. He is proficient in all aspects of electrical and instrumentation work, including switchgear installation, cable laying, and commissioning assistance. References are available from his past managers.
UTi is a global third-party logistics provider that has been operating for over 40 years. It provides transportation and shipping services worldwide through 319 offices in 59 countries. As a non-asset based company, UTi outsources transportation to third party carriers but coordinates shipping seamlessly. UTi aims to provide reliable, cost-effective and transparent services through its global network and long-standing carrier relationships. It seeks to offer customized supply chain solutions and has adopted a client-centric strategy to address customer needs.
Lawrence Dias has over 8 years of experience in operations and customer service roles. He currently works as a Senior Operations Analyst for DA-Desk in Dubai, where he coordinates between ship operators and agents on disbursement accounts and ensures accuracy and cost savings. Prior to this, he held customer service roles at EXL Service and operations roles at ASNA Construction in India. He has a Bachelor of Commerce degree from the University of Pune and is proficient in English, Hindi, and Marathi.
This document provides information about the "Simulation and Modelling 2016" knowledge transfer conference, which will take place on September 13-14, 2016 in Birmingham. The conference will discuss how simulations can replace physical testing and reduce costs in the automotive and aerospace industries. Day 1 will focus on automotive simulation and modelling, while Day 2 will discuss aerospace. The conference will address the latest developments in computer-aided engineering and how it is revolutionizing design, testing, and manufacturing. It will also cover challenges around integration, optimization, and validation of simulations. The agenda lists speakers from companies like Jaguar Land Rover, Rolls-Royce, and Boeing who will discuss their work in these areas.
I have done my industrial summer training from Bhilai steel plant which is a unit of SAIL. this is powerpoint presentation of my summer training. it includes all basic knowledge about the plant, process of manufacturing of steel and the factories inside it. you can get to learn new things from this presentation. Thank You !!
This document summarizes three case studies that demonstrate how simulation of reciprocating compressor valve dynamics can help optimize valve design and troubleshoot problems. Case 1 shows that reducing valve lift can increase compressor capacity while decreasing impact velocities and improving valve life. Case 2 illustrates that inadequate valve flow area leads to late valve closure and failure, and increasing flow area is needed. Case 3 demonstrates that considering cylinder flow area in simulations, in addition to valve design, is important, as insufficient cylinder area was constricting gas flow and wasting horsepower. Overall, valve simulation allows comprehensive evaluation of designs and selection of solutions that perform well over all operating conditions.
The document discusses the benefits of standby time in adsorption dehydration processes. It describes how molecular sieves are used to dehydrate natural gas and how their capacity declines over cycles due to loss of structure. Having excess regeneration capacity, or standby time, allows operators to reduce cycle times and extend the life of molecular sieves. The document presents a case study where performance testing revealed capacity would decline faster than designed. Using standby time by reducing cycle times allowed the unit to operate for longer than the planned 3 years before recharge.
The document discusses opportunities to improve compressed air efficiency at National Engineering Industries Ltd. It identifies several areas for focus: reducing air leakage, improving cleaning/air blowing processes, upgrading machinery to reduce air usage, regulating air pressure and flow, measuring air usage, and training staff. A survey found significant potential savings through initiatives in these areas, like installing valves to isolate air when machines are off, regulating pressure and nozzle size for air blowing, and improving machinery design. Implementation of the recommendations following a PDCA process could realize substantial cost reductions through more efficient compressed air usage.
- The document summarizes the internship report of Adnan Hatim Nek at the Pakistan Petroleum Limited (PPL) Sui Gas Field.
- It describes the various departments and processes at the Sui Field Gas Compression Station including QHSE, administration, planning, operations, machinery, and compression.
- Key parts of the compression process are described involving slug catchers, scrubbers, knockout drums, low pressure and high pressure compression and cooling.
How to unlock productivity savings in mining operations part 2. "Show me the ...David Mallinson MAICD
Selecting the right Idler Rolls and Idler Roll management systems for your conveyor is critical.When the conveyor stops....it all stops..the mine stops - and that's millions of dollars. Read how innovative technology and the IoT is used to minimise costs improve productivity and mitigate risk.
Understanding Paper Dryer Rotary Joint ReliabilityKadant Inc.
In the papermaking process, paper is dried on rotating, steam-heated, cast iron drying cylinders. Steam is supplied to each of these drying cylinders through a rotary joint and the steam that has condensed inside the dryers is removed by a syphon system that extends out through either the same rotary joint or a rotary joint on the other dryer journal.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document compares screw compressor and centrifugal compressor options for a chlorine gas compressor. Centrifugal compressors generally have higher efficiencies but lower turndown capability compared to screw compressors. For this application, a centrifugal compressor could provide annual electricity savings of $147,000 due to its lower power requirement. However, screw compressors are better suited if large swings in gas composition are expected, as centrifugal performance is more sensitive to changes in gas properties. Maintenance is easier for options with vertically-split casings. The document provides detailed technical considerations and specifications from multiple compressor vendors for each compressor type.
The document discusses how the LMS100 gas turbine by GE is well-suited to meet the needs of modern power grids that incorporate increasing amounts of intermittent renewable energy sources like wind and solar. The LMS100 can start and change power output very quickly, helping compensate for fluctuations from renewables. It is also highly efficient, able to use different fuels, and keeps emissions low without needing water. California in particular has installed many LMS100 turbines to help it meet renewable energy targets and manage the variability in renewable generation.
A compressed air & gas institute Question & Answer sessionSingh Ashwani
- Variable speed drive (VSD) compressors can be an effective choice for facilities with fluctuating compressed air demand as they allow compressor output to precisely match changing demand levels.
- VSD compressors reduce energy consumption and costs by lowering their output and electrical power usage during periods of low demand rather than idling at full load.
- A compressed air system audit is recommended to analyze a facility's demand profile and determine if a VSD compressor could provide energy savings of 30% or more compared to a traditional fixed speed compressor.
This document discusses the choice between reciprocating and screw compressors for air conditioning and refrigeration applications. There is no single best choice as it depends on factors like operating conditions, temperature levels, part load operation, refrigerant type, maintenance requirements, and space availability. Reciprocating compressors generally have lower energy consumption for higher temperature applications and part load operation, while screw compressors are more efficient for larger capacities and lower temperature applications. The optimal selection requires analyzing all relevant criteria for the specific application.
This document discusses methods for assessing compressor performance and optimizing compressed air systems. It provides formulas to calculate a compressor's actual free air delivery (FAD) capacity using the pump-up method. It also describes how to calculate system leakages using the unloading/loading time method and end-use air consumption using either the pump-down or unloading/loading time method depending on receiver size. The document explains that periodic assessment of compressor FAD capacity and air consumption patterns can identify optimization opportunities to reduce energy waste from compressed air systems.
- Steam trap testing intervals vary based on pressure, with weekly-monthly for high pressure and annually for low pressure traps. Four basic test methods are temperature, sound, visual, and electronic.
- Leaking steam traps waste steam and cost money. The cost of fixing a leaking 1/8" trap is $6,640 per year based on example steam costs.
- Proper steam trap maintenance is important to identify failed traps, which should account for less than 5% of total traps in a regular maintenance program.
- Compressed air leaks are a major source of wasted energy and pressure fluctuations. Leaks over 1/32" diameter can cost thousands per year to operate. Finding and fixing the largest leaks
BUSI2301 Introduction to Operations Management FVannaSchrader3
BUSI2301
Introduction to Operations Management
Fall 2021
Individual Assignment
1. Consider the total production (and sales) of ice cream in Canada (in millions of liters)
for the period 1995 until 2007 (from left to right):
341, 331, 317, 315, 321, 278, 298, 311, 302, 302, 335, 320, 285
Fit a model to ice cream production data using each of the following techniques and
forecast the 2008 production in each case. Also, plot the two moving average
forecasts and the actual, the two exponential smoothing forecasts and the actual, and
the linear trend and the actual (three graphs altogether).
a. Two-year moving average.
b. Four-year moving average.
c. Exponential smoothing with smoothing constant = 0.2.
d. Exponential smoothing with smoothing constant = 0.4.
e. Linear trend (regression).
f. Just by observing the plots, which of the above techniques would you use to
forecast the ice cream production and why? (Hint: The plot overall closest to
actual demand will be most accurate).
g. Alternatively, compute the MAD for each forecasting technique and determine
the most accurate technique.
Individual Assignment: BUSI2301
2 | P a g e
2. The number of Toyota Corollas produced in the Cambridge, Ontario, plant during each
month of January 2008 to December 2009 period was as follows:
Assume that the cars are sold in the same month they are produced. Identify an
appropriate forecasting technique, briefly state the reason(s) you chose it, and
forecast Corolla demand in January 2010.
3. Fleet managers have a large pool of cars and trucks to maintain.13 One approach to
the vehicle maintenance is to use periodic oil analysis: the oil from the engine and
transmission are subjected periodically to a test. These tests can sometimes signal
an impending failure (for example, iron particles in the oil), and preventive
maintenance is then performed (at a relatively low cost), eliminating the risk of failure
(failure would result in a relatively high cost). However, oil analysis costs money and
it is not perfect—it can indicate that a unit is defective when in fact it is not, and it can
indicate that a unit is nondefective when in fact it is. As a possible substitute for oil
analysis, the company could simply change the oil periodically, thereby reducing the
probability of failure. The fleet manager for the Southern Company, an electrical utility
based in Atlanta (parent of Georgia Power and Light), has four alternatives: (1) do
nothing, (2) use oil analysis only, (3) replace oil only, or (4) replace oil and do oil
analysis. For option (1) the probability of failure is 0.1, and the cost of failure is $1,200.
For option (2), the probability of failure remains at 0.1. If the unit is about to fail, the oil
analysis will indicate this with probability 0.7; if the unit is not about to fail, the oil
Individual Assignment: BUSI2301
3 | P a g e
analysis will indicate thi ...
This document advertises and provides an agenda for the "International EV Batteries 2016" conference on cost-effective engineering for hybrid and electric vehicles. The two-day conference will showcase innovations automotive companies are making to increase battery range, performance, safety and durability. It will feature speakers from companies like General Motors, Jaguar Land Rover, and McLaren discussing topics like battery pack design, testing, and lifecycle management. The conference aims to address challenges in developing electric vehicles and bringing stakeholders together to share solutions.
Eugene David Lockett is a qualified welder seeking a position in project management. He has over 25 years of experience managing electrical and instrumentation projects in various industries including oil & gas, mining, and petrochemical. His most recent roles include serving as site manager for Sasol projects with Stefanutti Stocks and Grinaker-LTA. He is proficient in all aspects of electrical and instrumentation work, including switchgear installation, cable laying, and commissioning assistance. References are available from his past managers.
UTi is a global third-party logistics provider that has been operating for over 40 years. It provides transportation and shipping services worldwide through 319 offices in 59 countries. As a non-asset based company, UTi outsources transportation to third party carriers but coordinates shipping seamlessly. UTi aims to provide reliable, cost-effective and transparent services through its global network and long-standing carrier relationships. It seeks to offer customized supply chain solutions and has adopted a client-centric strategy to address customer needs.
Lawrence Dias has over 8 years of experience in operations and customer service roles. He currently works as a Senior Operations Analyst for DA-Desk in Dubai, where he coordinates between ship operators and agents on disbursement accounts and ensures accuracy and cost savings. Prior to this, he held customer service roles at EXL Service and operations roles at ASNA Construction in India. He has a Bachelor of Commerce degree from the University of Pune and is proficient in English, Hindi, and Marathi.
This document provides information about the "Simulation and Modelling 2016" knowledge transfer conference, which will take place on September 13-14, 2016 in Birmingham. The conference will discuss how simulations can replace physical testing and reduce costs in the automotive and aerospace industries. Day 1 will focus on automotive simulation and modelling, while Day 2 will discuss aerospace. The conference will address the latest developments in computer-aided engineering and how it is revolutionizing design, testing, and manufacturing. It will also cover challenges around integration, optimization, and validation of simulations. The agenda lists speakers from companies like Jaguar Land Rover, Rolls-Royce, and Boeing who will discuss their work in these areas.
I have done my industrial summer training from Bhilai steel plant which is a unit of SAIL. this is powerpoint presentation of my summer training. it includes all basic knowledge about the plant, process of manufacturing of steel and the factories inside it. you can get to learn new things from this presentation. Thank You !!
This document summarizes three case studies that demonstrate how simulation of reciprocating compressor valve dynamics can help optimize valve design and troubleshoot problems. Case 1 shows that reducing valve lift can increase compressor capacity while decreasing impact velocities and improving valve life. Case 2 illustrates that inadequate valve flow area leads to late valve closure and failure, and increasing flow area is needed. Case 3 demonstrates that considering cylinder flow area in simulations, in addition to valve design, is important, as insufficient cylinder area was constricting gas flow and wasting horsepower. Overall, valve simulation allows comprehensive evaluation of designs and selection of solutions that perform well over all operating conditions.
The document discusses the benefits of standby time in adsorption dehydration processes. It describes how molecular sieves are used to dehydrate natural gas and how their capacity declines over cycles due to loss of structure. Having excess regeneration capacity, or standby time, allows operators to reduce cycle times and extend the life of molecular sieves. The document presents a case study where performance testing revealed capacity would decline faster than designed. Using standby time by reducing cycle times allowed the unit to operate for longer than the planned 3 years before recharge.
The document discusses opportunities to improve compressed air efficiency at National Engineering Industries Ltd. It identifies several areas for focus: reducing air leakage, improving cleaning/air blowing processes, upgrading machinery to reduce air usage, regulating air pressure and flow, measuring air usage, and training staff. A survey found significant potential savings through initiatives in these areas, like installing valves to isolate air when machines are off, regulating pressure and nozzle size for air blowing, and improving machinery design. Implementation of the recommendations following a PDCA process could realize substantial cost reductions through more efficient compressed air usage.
- The document summarizes the internship report of Adnan Hatim Nek at the Pakistan Petroleum Limited (PPL) Sui Gas Field.
- It describes the various departments and processes at the Sui Field Gas Compression Station including QHSE, administration, planning, operations, machinery, and compression.
- Key parts of the compression process are described involving slug catchers, scrubbers, knockout drums, low pressure and high pressure compression and cooling.
How to unlock productivity savings in mining operations part 2. "Show me the ...David Mallinson MAICD
Selecting the right Idler Rolls and Idler Roll management systems for your conveyor is critical.When the conveyor stops....it all stops..the mine stops - and that's millions of dollars. Read how innovative technology and the IoT is used to minimise costs improve productivity and mitigate risk.
Understanding Paper Dryer Rotary Joint ReliabilityKadant Inc.
In the papermaking process, paper is dried on rotating, steam-heated, cast iron drying cylinders. Steam is supplied to each of these drying cylinders through a rotary joint and the steam that has condensed inside the dryers is removed by a syphon system that extends out through either the same rotary joint or a rotary joint on the other dryer journal.
International Journal of Engineering Research and Applications (IJERA) is an open access online peer reviewed international journal that publishes research and review articles in the fields of Computer Science, Neural Networks, Electrical Engineering, Software Engineering, Information Technology, Mechanical Engineering, Chemical Engineering, Plastic Engineering, Food Technology, Textile Engineering, Nano Technology & science, Power Electronics, Electronics & Communication Engineering, Computational mathematics, Image processing, Civil Engineering, Structural Engineering, Environmental Engineering, VLSI Testing & Low Power VLSI Design etc.
This document compares screw compressor and centrifugal compressor options for a chlorine gas compressor. Centrifugal compressors generally have higher efficiencies but lower turndown capability compared to screw compressors. For this application, a centrifugal compressor could provide annual electricity savings of $147,000 due to its lower power requirement. However, screw compressors are better suited if large swings in gas composition are expected, as centrifugal performance is more sensitive to changes in gas properties. Maintenance is easier for options with vertically-split casings. The document provides detailed technical considerations and specifications from multiple compressor vendors for each compressor type.
The document discusses how the LMS100 gas turbine by GE is well-suited to meet the needs of modern power grids that incorporate increasing amounts of intermittent renewable energy sources like wind and solar. The LMS100 can start and change power output very quickly, helping compensate for fluctuations from renewables. It is also highly efficient, able to use different fuels, and keeps emissions low without needing water. California in particular has installed many LMS100 turbines to help it meet renewable energy targets and manage the variability in renewable generation.
A compressed air & gas institute Question & Answer sessionSingh Ashwani
- Variable speed drive (VSD) compressors can be an effective choice for facilities with fluctuating compressed air demand as they allow compressor output to precisely match changing demand levels.
- VSD compressors reduce energy consumption and costs by lowering their output and electrical power usage during periods of low demand rather than idling at full load.
- A compressed air system audit is recommended to analyze a facility's demand profile and determine if a VSD compressor could provide energy savings of 30% or more compared to a traditional fixed speed compressor.
This document discusses the choice between reciprocating and screw compressors for air conditioning and refrigeration applications. There is no single best choice as it depends on factors like operating conditions, temperature levels, part load operation, refrigerant type, maintenance requirements, and space availability. Reciprocating compressors generally have lower energy consumption for higher temperature applications and part load operation, while screw compressors are more efficient for larger capacities and lower temperature applications. The optimal selection requires analyzing all relevant criteria for the specific application.
This document discusses methods for assessing compressor performance and optimizing compressed air systems. It provides formulas to calculate a compressor's actual free air delivery (FAD) capacity using the pump-up method. It also describes how to calculate system leakages using the unloading/loading time method and end-use air consumption using either the pump-down or unloading/loading time method depending on receiver size. The document explains that periodic assessment of compressor FAD capacity and air consumption patterns can identify optimization opportunities to reduce energy waste from compressed air systems.
- Steam trap testing intervals vary based on pressure, with weekly-monthly for high pressure and annually for low pressure traps. Four basic test methods are temperature, sound, visual, and electronic.
- Leaking steam traps waste steam and cost money. The cost of fixing a leaking 1/8" trap is $6,640 per year based on example steam costs.
- Proper steam trap maintenance is important to identify failed traps, which should account for less than 5% of total traps in a regular maintenance program.
- Compressed air leaks are a major source of wasted energy and pressure fluctuations. Leaks over 1/32" diameter can cost thousands per year to operate. Finding and fixing the largest leaks
BUSI2301 Introduction to Operations Management FVannaSchrader3
BUSI2301
Introduction to Operations Management
Fall 2021
Individual Assignment
1. Consider the total production (and sales) of ice cream in Canada (in millions of liters)
for the period 1995 until 2007 (from left to right):
341, 331, 317, 315, 321, 278, 298, 311, 302, 302, 335, 320, 285
Fit a model to ice cream production data using each of the following techniques and
forecast the 2008 production in each case. Also, plot the two moving average
forecasts and the actual, the two exponential smoothing forecasts and the actual, and
the linear trend and the actual (three graphs altogether).
a. Two-year moving average.
b. Four-year moving average.
c. Exponential smoothing with smoothing constant = 0.2.
d. Exponential smoothing with smoothing constant = 0.4.
e. Linear trend (regression).
f. Just by observing the plots, which of the above techniques would you use to
forecast the ice cream production and why? (Hint: The plot overall closest to
actual demand will be most accurate).
g. Alternatively, compute the MAD for each forecasting technique and determine
the most accurate technique.
Individual Assignment: BUSI2301
2 | P a g e
2. The number of Toyota Corollas produced in the Cambridge, Ontario, plant during each
month of January 2008 to December 2009 period was as follows:
Assume that the cars are sold in the same month they are produced. Identify an
appropriate forecasting technique, briefly state the reason(s) you chose it, and
forecast Corolla demand in January 2010.
3. Fleet managers have a large pool of cars and trucks to maintain.13 One approach to
the vehicle maintenance is to use periodic oil analysis: the oil from the engine and
transmission are subjected periodically to a test. These tests can sometimes signal
an impending failure (for example, iron particles in the oil), and preventive
maintenance is then performed (at a relatively low cost), eliminating the risk of failure
(failure would result in a relatively high cost). However, oil analysis costs money and
it is not perfect—it can indicate that a unit is defective when in fact it is not, and it can
indicate that a unit is nondefective when in fact it is. As a possible substitute for oil
analysis, the company could simply change the oil periodically, thereby reducing the
probability of failure. The fleet manager for the Southern Company, an electrical utility
based in Atlanta (parent of Georgia Power and Light), has four alternatives: (1) do
nothing, (2) use oil analysis only, (3) replace oil only, or (4) replace oil and do oil
analysis. For option (1) the probability of failure is 0.1, and the cost of failure is $1,200.
For option (2), the probability of failure remains at 0.1. If the unit is about to fail, the oil
analysis will indicate this with probability 0.7; if the unit is not about to fail, the oil
Individual Assignment: BUSI2301
3 | P a g e
analysis will indicate thi ...
This paper investigates excessive fuel consumption of
compressor drivers caused by common compressor faults.
Pressure versus volume (PV) analysis techniques will identify
deficiencies, quantify fault severity, and will be used to
estimate the resulting excessive fuel consumption. Empirical
fuel measurements of the drivers are analyzed before and
after the fault correction and are used to calculate immediate
economic savings from repairs. Performance and capacity
improvements are also analyzed, providing a complete economic
picture of maintenance and operational payback.
The document discusses rethinking the use of approach flow screening on paper machines. It notes that removing centrifugal cleaners from approach flow 10 years ago resulted in dramatic energy savings, improved basis weight control, reduced web breaks by over 75%, better steam control, and increased yield. The document observes temporary 0.5-0.7 gsm reductions in basis weight from the timer-operated reject valve on the current pressure screen and slot screen system. It questions whether the electricity costs and basis weight control problems from the approach screen outweigh its benefits as a "security guard" and suggests starting to think about removing approach screens.
This document discusses condition monitoring of steam turbines through performance analysis. Performance analysis can detect degradation that reduces machine efficiency and output from things like deposits on blades and erosion of internal clearances. It outlines how to conduct valves wide open tests to monitor overall turbine performance over time. Examples are given showing how performance analysis detected efficiency reductions in high pressure sections of turbines due to blade deposition or other internal changes. Section parameters like enthalpy drop efficiency can also be monitored to localize areas of degradation. Condition monitoring through performance analysis helps determine when restorative maintenance is needed to retain turbines in service beyond their design lifetimes in a cost effective manner.
This document summarizes a method for optimally scheduling gas turbine compressor washing to minimize fuel consumption and emissions. It describes a dynamic model for estimating compressor degradation over time using a Kalman filter. It then presents an economic optimization model that considers fuel and maintenance costs to determine the optimal schedule and types of compressor washes (online, offline, idle) to maximize efficiency. Simulations showed potential fuel and cost savings compared to a fixed maintenance schedule by optimizing the timing and types of washes over a one-year period.
This document summarizes a method for optimally scheduling gas turbine compressor washing to minimize fuel consumption and emissions. It describes a dynamic model for estimating compressor degradation over time using a Kalman filter. It then presents an economic optimization model that considers fuel and maintenance costs to determine the optimal schedule and types of compressor washes (online, offline, idle) to maximize efficiency. Simulations showed potential fuel and cost savings compared to a fixed maintenance schedule by optimizing the timing and types of washes over a one-year period.
1. OTC 24688
Subsea Processing Systems:
Optimising the Maintenance, Maximizing the Production
Klas Eriksson and Konstantions Antonakopoulos, Aker Solutions
Copyright 2014, Offshore Technology Conference
This paper was prepared for presentation at the Offshore Technology Conference Asia held in Kuala Lumpur, Malaysia, 25–28 March 2014.
This paper was selected for presentation by an OTC program committee following review of information contained in an abstract submitted by the author(s). Contents of the paper have not been
reviewed by the Offshore Technology Conference and are subject to correction by the author(s). The material does not necessarily reflect any position of the Offshore Technology Conference, its
officers, or members. Electronic reproduction, distribution, or storage of any part of this paper without the written consent of the Offshore Technology Conference is prohibited. Permission to
reproduce in print is restricted to an abstract of not more than 300 words; illustrations may not be copied. The abstract must contain conspicuous acknowledgment of OTC copyright.
Abstract
Subsea pumping systems are increasingly used to increase production and extend lifetime of fields. More complex
subsea processing plants are being built, including subsea separation and gas compression.
When rotating equipment is placed on the seabed, the lifetime of such will typically be shorter than the operational
lifetime of the field, such that e.g. a pump will need to be replaced several times. This gives an increased interest in
Condition Monitoring techniques and Condition Based Maintenance, such that such interventions can be planned
in advance.
Gradual degradation of subsea equipment can be monitored, and intervention / replacement thus planned some
time in advance. The actual changeout of a subsea pump module typically takes 24 hours, but the preparatory
work before can take a month. Thus any advance warning will reduce the downtime (and production loss). This
paper describes a generic subsea separation/pumping/compression plant, and discusses some techniques for
Condition Monitoring and Condition Based Maintenance. Some experience from recent projects are presented
2. 2 OTC 24688
Introduction
Subsea pumping systems and stations are now commonly used subsea, 50+ subsea pumps have been deployed on the seabed.
Subsea compression stations are emerging, and are more complex.
A subsea compressor pilot has been built and operated for a year in a test pit on land for the Ormen Lange filed (15 MW
Compressor), and a subsea installation of 2 x 8 MW compressors is now being built for the Asgard field in Norway.
Subsea systems with rotating equipment will typically NOT operate for 25 years without service (for other subsea equipment,
like e.g. for a subsea well head system, 25 years design life is a typical requirement.)
Typical lifetime for a subsea pump or compressor is in the range 5 – 10 years, depending on how hard it is operated.
Knowing that some maintenance will be required, how do we optimize this in order to maximize the uptime and revenue
stream?
For subsea equipment, service is typically done by swapping a process module with a new one when necessary. Such a module
can weigh 50 tons for a pump module, and 150 tons for a compressor module. An intervention vessel with good crane capacity
is thus needed, and may take some time to find.
The spare module needs to be prepared for use and tested, and one may have to wait for good weather.
3 typical maintenance strategies are:
- Run until it fails (“if it works, don’t touch it”)
- Replace after e.g. every 2 years (this is typically done for aircraft)
- Replace when it is degraded but before it has failed (“just in time service”)
In practice one often uses a mix of these strategies. For my own car, I may:
- Replace the oil filter every 12 months or every 20 000 miles / 30 000 km, whichever comes first (time / runtime
based maintenance)
- If the tire thread wears down to less than 1/16th “ or 1.5 mm, plan tire replacement in a month or so (condition based
maintenance)
- If a rattling sound appears in the front wheel bearing, drive slowly to the nearest garage
We can do a coarse comparison of the cost of the 3 strategies using some typical generic data (the numbers will of course be
different for different fields and configurations, so this just gives an order of magnitude overview).
We assume that:
- It takes 24 hours to change out a module (once the installation vessel is on top of the installation, the module has been
tested and is ready for deployment)
- It takes 1 month to mobilize the spare module, a crew, check that the spare module works, mobilize a vessel with a 50
/150 ton crane, wait for good weather (this is typical data from experience. In some fields it might not be possible to
do any interventions at all for the 6 winter months)
- When a compressor or pump is shut down, the hydrocarbon production is decreased. The lost revenue can be 3
MUSD/day for a subsea compressor, and 0.5 MUSD/day for a subsea pump.
- The cost for the module replacement operation is approximately 3 MUSD (in addition there will be a cost for
repairing the faulty module, but this is not considered in this discussion)
- The lifetime of the pump / compressor is 5 years, i.e. it will break after 5 years operation (this can be less, and it can
be more).
If we “run until it breaks”, then we will get a 30 day shutdown every time. The cost per breakdown then becomes 30 x 0.5 + 3
= 18 MUSD for the pump, and 30 x 3 + 3 = 93 MUSD for the compressor.
Assuming they break after 5 years, the average cost per year then becomes 18 / 5 = 3.6 MUSD/year for the pump and 93 / 5 =
18.6 MUSD/year for the compressor.
If we replace the pump compressor / pump every 2 years (while they are still operating well), the risk for unplanned
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breakdown is greatly reduced. This is the approach taken by the aircraft industry, which has a good record in this area.
As we have a much shorter production stop (1 day instead of 1 month), the cost for each replacement is 0.5 + 3 = 3.5 M$ for a
pump and 3 + 3 = 6 M$ for a compressor. The average cost per year becomes 3.5 / 2 = 1.75 MUSD/year for the pump, and 6 /
2 = 3 MUSD/year for the compressor.
One should point out that there is always a certain risk with subsea interventions; something could get damaged by the
intervention itself. The cost of this risk should be entered into the calculations. The old wisdom “if it works, don’t touch it”
points to this factor.
There is also a cost for refurbishing the replaced compressor module such that it is ready for use, this should also be added to
the calculation for completeness. This has not been included in this simplistic calculation.
IF we are able to detect faults developing a month in advance, then we can do service “just in time”. This is of course a big IF,
and this is the main topic for this paper.
Assuming that this can be done, such that we will be able to see a fault developing a month ahead or more, and plan the
intervention just in time (i.e. after 5 years operation), the average cost then becomes 0.5 + 3 / 5 = 0.7 MUSD/year for the
pump, and 3 + 3 / 5 = 1.1 MUSD/year for the compressor.
Cost per year for the 3 tactics then becomes for a pump
Run to break: 3.60 M$/year
Replace every 2 years: 1.75 M$/year
Replace “just in time”: 0.70 M$/year
So, for a pump system we see here that the potential for cost saving by doing service “just in time” is in the order of 3 M$/year
per pump. If we can see a fault 1 month ahead of time just once, we will gain 15 M$ in reduced deferred production.
The cost per year for the 3 tactics for a subsea compressor likewise becomes:
Run to break: 18.60 M$/year
Replace every 2 years: 3.00 M$/year
Replace “just in time”: 1.10 M$/year
For a subsea compressor system we see here that the potential for cost saving by doing service “just in time” is in the order of
17 M$/year per compressor. If we can just once see a fault 1 month ahead of time just once, we will gain 90 M$ in reduced
deferred production.
From the calculations above, even if they are generic and simplified, we can see that there is a potential for saving costs by
optimizing the maintenance, particularly if one can detect failures some time before the machine breaks down.
This concept is commonly used topside, and is called CBM or Condition Based Maintenance. A simplistic definition (from
www.wikipedia.com ) is
“Condition-based maintenance (CBM), shortly described, is maintenance when need arises. This maintenance is performed
after one or more indicators show that equipment is going to fail or that equipment performance is deteriorating.”
It does not work for everything. Your own car, however well maintained, may always suffer a sudden breakdown on the
highway. However, good maintenance can reduce the risk of this happening, giving a higher average uptime.
Some faults develop slowly over time, and some of these can also be measured such that one can track the degradation over
time. For these types of faults, CBM can be applied.
How fast a machine wears depends on how hard it is driven. E.g. for certain types of bearings the lifetime is related to the
power at which the machine runs. If the machine runs at twice the power, the bearing wears out in 1/8 of the time, and if the
machine runs at half the power the bearing will last 8 times longer. For such a bearing, if the machine runs at e.g. 80% power
instead of 100%, the bearing life is almost doubled.
Conversely, if the machine is run at 120 % power, the bearing life is halved.
So in this case, by monitoring the power at which the machine is run, one can estimate how much lifetime there is left in the
bearing, and when this is down to e.g. 1 month one should consider intervention and replacement.
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This is a typical example of Condition Based Maintenance, or CBM.
CBM is actually used in some cars. Traditionally car service has been interval based, e.g.: “Replace oil filter every 12 months
or 20 000 miles / 30 000 km, whichever comes first”. More advanced cars now have sensors which measure how card the car
is driven, and automatically suggests service intervals based on this.
Figure 1 Condition Indicator in a car
The sample shown above indicates 5 green bars when the car has been newly serviced and is in perfect shape.
The green bars go out one by one. The harder the car is driven, the faster they go out.
When the yellow warning light goes on, the engine oil should be changed within 1 month.
When the red light goes on, the engine oil should be changed immediately (drive to the nearest garage, there is an imminent
risk of engine damage).
So, the whole idea with CBM is to get some advance warning before something breaks down.
This in turn will give us less downtime.
The ultimate goal for CBM is thus “Service just in time”.
In practice, this is not possible for all faults. There will always be instantaneous breakdowns, just as with a car.
It is not always possible to see a fault developing a month ahead of time (but all advance warning is good, 3 days advance
warning means 3 days less downtime).
The terms Condition Monitoring and Condition Based Maintenance are to some extent overlapping. One simple definition is
as follows:
Condition Monitoring = Measuring and monitoring the state of the machine (historic and current data, “Now” and “Earlier”)
Condition Base Maintenance = Using this information to do service “just in time” (extrapolate into “Future” and plan when to
do it)
In practice, one normally uses a mix of strategies. Again using my own car as an example:
- Change the oil filter at least once per year (time based maintenance)
- Change the oil filter every 15 000 km or 10 000 miles (mileage based maintenance)
- Monitor the tire threads, and if the pattern becomes less than 2 mm or 1/16th “ schedule a tire replacement some
convenient day within the next month (CM / CBM)
- If I hear a rattling sound in the front bearing I’ll slow down and drive carefully to the nearest garage (or call a tow
truck) (CM/CBM)
CM/CBM systems have been used topside for many years (a Google search for “pump condition based maintenance” gives 6
M+ results), and are now being deployed subsea by most vendors to varying extents.
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Figure 2 CB/ CBM Pyramid
All CM/CBM systems have similar buildingblocks as sketched above, namely:
- Sensors (to measure a physical property, like pressure, temperature, speed, vibration,…)
- Data acquisition system (to capture the signals into an electronic system)
- Data storage system (to store the signals for some time for analysis)
- Viewing and Analysis capability (for viewing and analysing the stored data)
- Calculation of KPIs (e.g. the efficiency of a pump)
- Prediction of remaining lifetime (time to service)
The lower levels can be called Condition Monitoring, and the higher level Condition Based Maintenance.
Condition Monitoring views current and past state of the machine, and Condition based Maintenance tries to look into the
future and predict when maintenance should be done (preferably a month ahead).
The difficult part is the CBM part. We can (and do) easily log millions of data per second, and store them for months in multi-
Terabyte database (the one for Ormen Lange Pilot and Asgard has a 60 TByte harddisk, which fills up in a month or two).
The hard part is to make sense of the data, and ideally convert it to green, yellow and red lights as we saw for the car indicator
above.
Today we can do this for some degradation mechanisms, of which a few will be discussed further down. However, much
remains to be done in this area.
As we gather more operational experience of such subsea systems, we will learn how to make better use of the logged data for
CM and CBM purposes.
We do not know today how the data we are logging will be used in a few years’ time. But if we never logged it, we can never
analyse it! The cost difference between logging a few data (which you know what to do with) and logging all data (hoping you
may have use for it later) is not that high. Computer hardware is cheap, the main cost is for logging the first data (=setting up
the infrastructure), whether 1 or 1000 data points are logged usually don’t differ much in cost.
A simple approach is thus to log and preserve as much as possible, and actively spend time to analyse it to make more and
more sense of it.
Typical subsea plant pump / compressor
We will discuss a couple of typical subsea plants involving rotating equipment.
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Figure 3 Typical subsea pumping station
In the picture above we show a generic subsea pumping station. It consists of two physical parts, one lower manifold module
(with very few moving parts and sensors) and one upper part with the pump, sensors, accumulators and most valves.
The pump module can be quickly disconnected from the manifold by opening 2 clamp connectors, and can be replaced with
another one in 24 hours.
If the pump fails, the production flow can be diverted around the pump (but will flow at a lower rate).
Figure 4 Ormen Lange Pilot subsea Compressor sketch, process part
In the picture above is shown a typical subsea compression plant (Ormen Lange Pilot). At the inlet is a scrubber which
separates any liquid from the incoming wet gas.
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The liquid is boosted by a pump, and the dry gas is boosted by a compressor.
The high pressure gas and fluid are then recombined and pushed into the flowline.
The compressor has a recycle loop through a recycle cooler, which is used for start-up and for avoiding surge conditions.
Figure 5 Ormen Lange Pilot subsea Compressor sketch, electro system part
For the Ormen Lange pilot, subsea units for Variable Speed Drives (VSDs), High Voltage Circuit Breakers (HVCB) and Un-
interruptible Power Supplies (UPS) were also developed. These are necessary due to the very long stepout (150 km for Ormen
Lange). A VSD must be located within 50-100 km from the motor for stability reasons, so for very long step-outs it must be
located subsea.
The UPS can be located either topside or subsea. For Ormen Lange pilot, a subsea UPS module was qualified. One main
purpose for this is to keep the magnetic bearing powered long enough for a safe coast-down in case there is a sudden power cut
in the HV system on land.
Long distance HV transmission voltage is 132 kV, and is transformed down at the subsea end to 22 kV.
The HVCB module is used for distributing HV power at the 22 kV level to various consumers subsea, and for isolation of
faulty equipment in case of malfunction.
One HV cable can supply enough power to drive 2 complete compressor trains. If there is a malfunction in one, it can thus be
isolated and the other train kept running.
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Figure 6 Ormen Lange Subsea Compressor Pilot in test pit
In the picture above the Ormen Lange pilot station is shown while being installed in a test pit at Nyhamna/Norway, where the
landfall is for the Ormen Lange gas field. It has since then been operated for 1 year +.
For Condition Based Maintenance some kind of performance indicator is needed, which can be tracked and used to predict the
remaining useful lifetime of a component.
Such an indicator (or KPI) needs to be:
- Possible to measure
- We must have an idea at what level of degradation we must replace the component
- We must be able to predict the evolution of the KPI sometime into the future, such that we can get advance warning
(ideally 1 month, but every day of advance warning helps)
Typical monitoring and prediction techniques
We will now go through a few typical examples of wear and tear mechanisms which are suitable for use for CBM.
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Figure 7 Typical KPI concept used for CM/CBM
This picture above is from a simple system used for a subsea pumping system a few years ago. However it illustrates the basic
concept:
- The KPI is plotted over time
- The evolution into the future is estimated (based on knowledge of the underlying degradation mechanism, and fitting
a curve to the observed data)
- An acceptance limit is defined
- The time remaining until the KPI reaches the acceptance limit is calculated
If this is < 30 days, a “yellow alarm” is triggered
If this is < 10 days a “red alarm” is triggered
Figure 8 Typical KPI: Pump lube oil consumption
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One example of such a KPI is for the lube oil consumption in a subsea pumping system. For this particular application, the
lube oil is supplied through a very long umbilical, and due to the high viscosity of this particular lube-oil, only a fairly small
amount can be supplied per hour through the umbilical.
The lube oil leaks from the motor into the process, and this leak will increase over time as the pump seals wear.
By plotting the lube oil consumption over time, one can then estimate fairly accurately how much time is left until the limit is
reached.
(Once the limit IS reached), the overpressure in the motor versus the process will be lost. One can then for a while reduce the
motor speed to compensate, but this will give a production loss).
Figure 9 Typical KPI: Number of active accumulators
For the same pump station, short term variations in lube oil consumption are handled by a bank of subsea accumulators. 4 of
these are required in order to get the required pressure/time characteristics.
Peak demand occurs after a shutdown as the motor cools down, and a large amount of fluid is needed in a short time due to
cool-down and contraction effects. It is not possible to supply the required amount of lube oil fast enough through the
umbilical, so subsea accumulators are required to handle the peak demand.
For redundancy, 8 accumulators are used. One can thus afford to lose 4 of them, but if 5 are lost the module should be
replaced, as the overpressure can then not be held in the motor during a shutdown.
To monitor how many accumulators are operational, a calculation is done every time there is a pump stop (for whatever
reason).
The observed pressure/time curve is compared with several simulated cases (for 8,7,6,… live accumulators) to determine how
many are operational.
Over time, the accumulators may stop working one after one (e.g. through loss of nitrogen pre-charge), and when only 4 are
functional the pump module should be replaced.
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Figure 10 Typical KPI: Power supply quality to motor
The subsea VSDs used for the Ormen Lange Pilot generate a certain amount of harmonics. These are basically converted to
heat in the motor. The allowable amount of harmonics is specified in IEC norms, and the motor lifetime is calculated based on
this.
If the amount of harmonics is higher, the motor lifetime will be shorter.
The VSD has some ageing effects such that the amount of harmonics is expected to increase over time.
When it gets too bad, VSD replacement should be considered.
Figure 11 Typical KPI: Long term logging of THC
For the Ormen Lange pilot, the total amount of harmonic current (THC) is calculated every second and logged as a long term
trend. Above is such a log, One can see that there are large transients during start / stop / speed changes, this is quite normal. It
is the long term trend which should be monitored. As the harmonics exceed the specified limit, the temperature in the motor
windings will increase, and the lifetime of the motor will degrade.
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Figure 12 Typical KPI: Magnetic bearing current
The Ormen Lange and Asgard subsea compressors have magnetic bearings in order to get a longer lifetime before service is
required. 3 radial and one axial bearing are used.
Each radial bearing has 4 magnetic coils and 2 position sensors.
For one coil pair, a plot is shown above of current used in top and bottom coil and the position sensor associated with this coil
pair.
Over time, as the compressor becomes more and more unbalanced, the magnetic coils need to work harder and harder to hold
it centred (i.e. more current is required).
There is a limit to how much current the magnetic bearing control system can generate, so eventually it may get overwhelmed.
Then it can no longer hold the shaft centred, the shaft will hit the backup bearing and the compressor will trip.
Operation may continue at a lower speed, but there will then be a production loss.
By monitoring the current over time, one can track how the available margin decreases over time, and replace the compressor
before the magnetic bearing system is overwhelmed.
To be more precise, the amount of current the amplifier can provide also depends on the frequency. An amplifier can provide
more power at a low frequency than at a high frequency, such that a high order harmonic may overwhelm the amplifier
although there is plenty of power left.
Figure 13 Typical KPI: Compressor head deviation from expected
One more possible KPI to track is the head generated by the compressor.
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For a given flow and speed, a certain head is expected (from the compressor curve measured when the compressor was new).
Over time, as the compressor wears, it will generate less head
Less head means that less gas is pushed through the flowline
This can be compensated for by running the compressor faster. However, if the compressor is already running at max speed,
then a loss of e.g. 10% head means 3 % less flow.
Assuming the compressor gives a production increase of 3 M$ day, a loss of 5 % flow is a loss of 30 x 0.03 * 3 M$/month or
2.7 M$ / month, or 32.4 M$/year.
Considering that the cost of a compressor module replacement is in the order of 6 M$, a head loss of just a few % over a year
can thus justify a compressor module replacement.
There are of course risks associated with subsea interventions, so we are not suggesting to replace the compressor every time
the head drops 1 %. However, this parameter is easy to calculate and track, and can then be used for a cost / benefit discussion
on when to replace the compressor.
Whenever a pump or compressor is started, one can log the vibration while the speed is changing. This
can give valuable information about critical frequencies and other issues. Below are shown some typical
such analysis, one for a pump and one for a compressor.
Figure 14 Vibration signature during pump speed change
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Figure 15 Vibration signature during compressor acceleration
So, looking at the CBM pyramid shown above, what can we do today?
There are qualified sensors available for most parameters of interest. A few are missing, and development programs are
ongoing. This is true e.g. for:
■ Displacement sensors for use inside pump mechanical bearings
■ Sensors for oil droplets in water, liquid droplets in gas, and solids in liquid
Data acquisition systems are available, with high sampling rates (e.g. 10 kHz for Ormen Lange pilot, even higher for Asgard)
Data storage systems (for Ormen Lange pilot approximately 1 M data samples are stored every second, and much more for
Asgard system)
For viewing of data, several software packages are available more or less off the shelf.
For analysis of data, it gets more complex. Some types of analysis are off-the-shelf (e.g. harmonic analysis), but the
interpretation of the data is more complex, and involves equipment expert who understand how to interpret the data. The
algorithms then need to be prepared with a deep knowledge of the equipment involved.
In the area of KPIs, which can be used to look ahead and predict when to do intervention, there are some that are well
understood and useful already today.
There are several more which are in various stages of development, but it in this area that much more work is needed,
component by component, in order to better understand the deterioration mechanism and how this may be observed by sensors
(direct or indirect).
The ultimate goal is to have an indicator for each and every component with green / yellow / red bars as shown earlier, giving
the “time to service” for each one.
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Conclusion
For subsea plants, due to the high cost and long time needed for intervention, it is of great interest to monitor wear and tear
mechanisms wherever possible.
Any advance warning before a breakdown will give a shorter shutdown, and less production loss.
Logging and analysis of data can thus be profitable. “Run until it breaks” is probably not a good idea for subsea rotating
equipment, where the anticipated lifetime is in the order of 5 – 10 years, and depending on how the equipment is operated.
Data logging systems and analysis tools are available right now more or less off the shelf. As much data as possible should be
logged, “If it was never logged, you can never analyse it”.
We don’t know today how we will use the logged data in 5 years’ time, so the simplest option is to log and save everything
(the cost difference between logging 10% of the data or 100 % of the data is not that big).
The missing link is where we turn the data into useful information, i.e. green/yellow/red indicators.
We can do this today for some parameters, and we have ideas under development for 50 more, but much more work is needed
in this area.
Systems like this are already being deployed, especially for subsea pumping and compression stations.
Using such systems will aid in increasing the uptime and production while reducing the maintenance costs.
Acknowledgements
Norske Shell AS