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For process plant components and equipment, lifecycle costs can dwarf up-front purchase costs. This is particularly true nowadays because of rising energy prices, higher labor costs and the increasing need for uptime. But automation can help monitor, control and cut lifecycle costs.Lifecycle costs represent the total cost of ownership of an asset, such as a control valve, reactor vessel, boiler or any other piece of equipment. (For a more complete description, see "Lifecycle Cost Definitions.")
How can automation be used to monitor, control and cut lifecycle costs for process equipment and components? The "big three" are reducing stress on equipment, enabling proactive maintenance and cutting energy use.
First is eliminating process upsets. As an anonymous refinery engineer explains, "Improved automation reduces stress on equipment caused by process upsets and unplanned unit shutdowns." Reduced stress obviously leads to fewer equipment breakdowns and lower maintenance costs.
"Our installation of a modern DCS reduced the number of upsets and trips," he continues. "Our operations and maintenance managers noted considerable improvements in production rates and mean time between failure rates. None of these control systems had as their express purpose cutting lifecycle costs, but the net effect of screwing up less often was to reduce lifecycle costs. If you don't break it, it doesn't need to be fixed."
Kenneth Marse, control systems specialist at Galata Chemicals (www.galatachemicals.com) in Taft, La., says his facility reduced lifecycle costs by eliminating the need to shut down the process to perform maintenance or repairs. Fewer shutdowns and start-ups equated to smoother running plants and extended equipment life.
The Taft plant uses four separate DeltaV control systems from Emerson Process Management (www.emersonprocess.com). AMS Device Manager software monitors the smart devices continuously, and raises alarms if any preset operating limits are exceeded. Some parts of the monitoring system rely on wireless communication back to the AMS.
"Every morning I check the alert monitor in AMS," Marse reports. "In one example, AMS gave an alert on a level transmitter that operators thought was working properly. I ran diagnostics on the instrument and found the electronics were going bad. We were able to order new electronics and plan the work while switching production. The result was no unscheduled down time, which means no loss of production. Catching a potential problem before it occurs avoids a great deal of troubleshooting and eliminates downtime."
Energy savings is the third big key to cutting lifecycle costs. Glenn Givens, president of Givens Control Engineering in Burlington, Ontario, Canada (www.givenscontrol.com), has been involved in several projects that simultaneously cut energy costs and increased equipment life.
"We automated the screening process for stock pulp used to fill a large tank at a paper mill," Givens explains.
"The whole system had to be ramped up to about 20 times the existing throughput." The concept was that the pump and screen motors could then be operated for approximately 5% of the time, saving energy and wear and tear." As an additional benefit, pump and motor life would be greatly extended.
"The two motors in question are 200-hp each, consuming 165 kW," Givens says. "Estimated savings were $30K to $40K annually." (See "Automating for Energy Savings," for more on this project.)
Givens Control Engineering has done other projects that successfully saved energy. In one case, however, reluctant operators gummed up the works.
Refiners are high energy-consumption devices used in paper mills to cut fiber to shorter length. On a paper machine that had two refiners, operators could shut one down in some instances, saving 100 kW per hour.
Givens wrote a program to look at the tonnage, energy per ton and other factors, and display on the DCS when it was permissible to shut down one of the refiners. It couldn't be done automatically because it required manual closing and opening of valves.
Unfortunately, this program wasn't successful because operators didn't implement the shutdown sequence. "Some operators may have felt that quality would be higher running two refiners in parallel, or that there could be a risk of getting out of quality specs when doing so," says Givens. "Or it may have just been easier for operators to ignore it."
Givens recommended installing automatic open/close valves to automate the shutdown, but it never happened. Operators need to "buy in," to make such a system work. (See Table 2, for more difficulties in implementing lifecycle management systems.)
Equally important as operator buy-in is getting management to approve the concept and purchase the necessary equipment and services. "A critical success factor in implementing advanced automation is gaining acceptance of the approach across the organization," says Ann Feitel, director of planning for asset optimization at Emerson Process Management.
Paula Hollywood, senior analyst at ARC Advisory Group (www.arcweb.com), adds, "The greatest challenge is changing the corporate culture. People are inherently resistant to change. Clearly stated objectives help all the players understand their roles. Continuous monitoring and feedback need to be part of the process to keep people engaged."
Management bought into an automation plan at the Florida Keys Aqueduct Authority (FKAA, www.fkaa.com). The FKAA developed a 20-year strategic master plan to both improve its water processes, and to develop an automation system migration plan to replace its 20-year-old equipment that was expensive and difficult to maintain. The authority also wanted to expand and modernize the capabilities of the control system. The FKAA wanted a common communication platform, a common programming language and remote monitoring capabilities.
The FKAA used Lifebook from Schneider Electric (www.schneider-electric.com), an analysis tool that gives a facility-wide view of the automation system and helps determine a long-term strategy for the automation infrastructure. With this as a guide, FKAA upgraded 36 stations from the old controls to Schneider Electric's Modicon Quantum and M340 PLCs and Magelis HMIs (Figure 1).
In addition to all the usual benefits of automation, technicians are now able to communicate remotely with the PLCs, reducing maintenance costs over the lifecycle.
"Prior to the upgrade we had to travel to the offending PLC when there was a problem, covering as much as 130 miles. Just the transportation and overtime costs to send a technician to one site was huge," said Carl Brewster, chief information officer, FKAA. "We've now eliminated any need to travel to any PLC for troubleshooting. Our technicians can identify the problem remotely and then take any needed equipment with them."
Any automation upgrade that makes maintenance easier ultimately cuts lifecycle costs because it encourages on-time repairs rather than running to failure.
Automating process plant HVAC and lighting systems can require another level of management buy in, but the results are often worth the trouble. Energy is the largest controllable cost in most processes, so finding efficient ways to conserve energy is a key to profitability," observes Jeff Payne, product manager of automation and controls at AutomationDirect (www.automationdirect.com)."One of the first steps is installing a system that allows you to meter your energy consumption and collect that data. From here, you can observe typical usage and find opportunities to optimize your process to minimize waste," adds Payne.
"The primary objective is to achieve optimum operating efficiency with emphasis on reliability and low cost," says Sam Morello, PE, president of ARM EnerTech Associates (AETA, www.armgroup.net), a system integrator affiliated with AutomationDirect.
AETA uses PLC-based energy management systems to save their clients substantial sums. With an installed base of over 400 AutomationDirect DirectLogic 205-PLC systems in five eastern states, AETA energy managements systems reduce costs by monitoring and controlling temperatures from refrigeration units and HVAC systems, and by optimizing lighting zones.
The AETA systems make adjustments as necessary to maintain a continuous operation without wasting energy. Their automated systems use technology to generate audible, visual and email alarms when configured parameters are out of spec. All of this data is then linked back to user-specified viewing media across each company's LAN/WAN, which also allows for remote control of system parameters.
One major purpose of lifecycle management is to extend the useful life of an asset. Gary Crenshaw, a control systems engineer with Beam Global Spirits and Wine (www.beamglobal.com) in Clermont, Ky., did just that.
In the early 1990s, Beam Global had a coal-fired boiler that was scheduled to be replaced because it was running badly. "We decided to replace the original 1950s-60s controls until the replacement boiler could be budgeted. We put an L&N Micromax on the boiler and added O2 monitoring and other instruments. The boiler ran so much better with the new controls that the project to replace it was canceled."
That was 10 years ago. "The Micromax became obsolete," says Crenshaw. "We replaced the Micromax with an (Allen-Bradley) PLC5/40. Now, PLC 5s are nearing obsolescence and will soon be replaced, but the boiler is still in service."
Apparently, there was nothing wrong with the boiler itself. "The old controls were so bad it just appeared the boiler was no good," he notes. "The operators had to watch the drum level and control the feedwater valve manually. They would also have to watch the coal feed and air flow, and manually adjust these. That's because the old controls no longer worked. The automatic controls solved these problems."
Using automation to extend the boiler life also eased EPA permitting. Regulations said that existing coal-fired boilers could be permitted with upgrades, and a new coal-fired boiler would have been almost impossible to permit.
Reducing required maintenance, cutting time to repair and improving maintenance operations and assets are big advantages of improved lifecycle management.
"With thousands of pieces of equipment in a plant, knowing the health of assets and predicting problems can prevent upsets, reduce maintenance costs and improve availability," says Emerson's Feitel. "Predictive technologies alert staff when equipment such as motors, pumps and control valves are experiencing problems. By evaluating the performance of control valves, planned overhauls of critical valves can often be delayed for years, saving substantial costs and maximizing production uptime."
Studies by Rockwell Automation (www.rockwellautomation.com) have found that 15% to 40% of the indirect costs of a manufacturing facility are devoted to maintenance, with about 50% of that estimated to be unnecessary. "Almost half of all maintenance activity is corrective in nature, which is 10 times more costly than predictive maintenance," says Ben Mansfield, marketing manager, PlantPAx process automation systems, Rockwell Automation. "For lifecycle cost savings in maintenance, we recommend integrated condition monitoring on all rotating equipment."
Getting information to the maintenance system is also important, and the easier the interface the better. "One example of this is the integration between Endress+Hauser (www.us.endress.com) field devices and the Rockwell Automation PlantPAx process automation system," says Mansfield. "Using open, standard technology at every level, the system comes with tools that provide fast system engineering and reduced risks."
For example, in May 2009, the Colorado Springs Utilities (CSU) McCullough Complex water treatment plants converted to a fully integrated Rockwell and Endress+Hauser control system solution. "The new automation system reduced our concern about poor water quality because we could run more efficiently and now had time to fine-tune our operations," says Steve DellaCroce, customer operations superintendent at the McCullough Complex.
In addition to an increased confidence in water quality, CSU was able to reduce annual operating costs by $240,000 due to fewer system operator hours required to perform monitoring and trending tasks. CSU estimates an additional $40,000 annual savings on system support and maintenance.
In these and other instances, a well-designed automation system can cut lifecycle costs in myriad ways. The primary goals for most automation projects are to improve product quality and consistency while reducing labor costs. But once challenges are overcome, the reduction in lifecycle costs can turn out to be a key benefit of many an automation project.