Whenever there’s an economic turndown and chemical companies need to cut costs, maintenance in particular comes under the fiercest of spotlights. However, more firms are finding that adopting lifecycle analysis (LCA) and lifecycle costing (LCC) and relying on condition-monitoring and other diagnostic techniques are more cost-efficient ways to save on maintenance than simply slashing budgets.
A good example is BASF, Ludwigshafen, Germany, a company that takes an integrated LCC approach from conceptual engineering through procurement to maintenance/operation.
“LCA can be done on entire plants, subsystems or components. Operational/maintenance experience is looped back into the engineering process of a new plant and reliability, availability, maintainability (RAM) studies and other tools are used for LCC improvements,” says Kurt Raschka, its senior vice president for maintenance at Ludwigshafen.
During the operational phase, for example, the company uses a method it calls risk-based maintenance (RBM) to identify the critical components of a plant and to decide on suitable risk-mitigation measures. Detailed LCA can be done on specific components such as large compressors. Because BASF operates a large variety of different plant types with diverse process requirements, the detailed program is mostly decided at plant level, based on a global collection and exchange of best practices (Figure 1).
Raschka believes that it’s important to analyze specific equipment within its respective process environment. For example, as teaming of variable frequency drives (VFD) with pumps has become more common due to increasing power costs and declining converter costs, BASF looks at the combination. This doesn’t mean that the company now only is using pumps with VFDs but that this option is evaluated.
Figure 1 -- Tailored program: At BASF,
“A good example for a lifecycle approach is in the area of distributed control systems (DCS) where BASF procures DCS with a functional lifecycle guarantee — we buy ‘functionality’ instead of ‘pieces of electronic equipment,’” explains Raschka. “This concept can also be extended to the field instrumentation. A different example of LCC improvement is our program to reduce the variety of valves through standardization. By standardization we can reduce the initial purchase price as well as spare part costs, etc., therefore finally reducing lifecycle costs.”
Although reluctant to name companies, Raschka says BASF is working with specific DCS, instrumentation and rotating-equipment vendors on new technologies that can give additional economic advantages. “For example, low-cost smart integrated vibration-monitoring sensors can be used in many applications due to their ‘intelligence’ and decreasing price. The new bus-based instrumentation systems come with a lot of possible functionalities which we use case-by-case. We always ask for the additional value in the first place, rather than for the new technical features. Usage of features without additional value in a specific operational application might have a negative impact of increasing complexity and costs,” he says.
Overall, BASF places a significant emphasis on creation of value in capital investment, operation and maintenance. LCC considerations and their benefits cannot be separated, says Raschka, as they are an integral part of economic decisions.
Another big Advocate
LCC considerations also are important to Todd Overbeek, master black belt and lean program leader in the maintenance department of Eastman Chemical, Kingsport, Tenn. (Figure 2).
“The facility here in Kingsport is huge. It’s like many plants within a plant and we have a maintenance staff of around 1,300. Within that there is a whole reliability department of around 50 people that is dedicated to improving equipment reliability across the site. This department includes 10 or 11 reliability engineers: mechanicals, electricals and chemicals, who have been specifically trained to tackle reliability issues.”
The focus on reliability has changed considerably over recent years, with everyone in the department now attending two-day LCC analysis classes given by a consultant, says Overbeek.
“Most engineers and technicians from outside the department also go on this class, too, because Eastman is very big on giving people the skills and knowledge they need to do the job properly,” explains Overbeek. “So interest in LCC has grown a lot in the last five years as the company is always looking to find new techniques and skills — anything that will give clues to equipment performance.”
Figure 2 -- Tennessee titan: Eastman’s
Eastman is in the early stages of formalizing its maintenance strategies and doesn’t yet rely on a defined LCC program at Kingsport. “The age profile of our engineers is older than in many U.S. chemical companies and they have a huge amount of experience. So, for example, they understand and realize that in a certain situation it would be better for us to purchase a more expensive API pump than a cheaper ANSI one,” says Overbeek.
Sometimes, the cheaper option may make more sense, as one maintenance engineer documented. He completed a simple LCC on rotary air locks (RAL) in a TPA (terephthalic acid) plant that led to change from units costing $20,000-plus to ones costing $6,000. “…the repairs on [the expensive RALs] were running around $6,000 to $8,000. The high cost for the repair was due to the body being damaged and the machine work that was necessary to fix them. The bore is tapered and it’s very difficult to get a good machining job and to have the performance be good when the repair is complete… So we decided to go with [the less expensive RALs] and, if they failed, we could just buy new ones cheaper than rebuilding the [more expensive units]. Since that time, we have started to rebuild [the less expensive units] and I guess the rebuild cost is around $2,000 to $3,000, unless they have body damage and then they are replaced. They are not tapered and the clearance is fixed, so the body doesn’t get damaged as often...”
Says another: “Most equipment upgrades are justified based on some aspect of LCC, usually just the M&R (maintenance and reliability) aspect but I have also used energy savings due to improvements in efficiencies as part of the justification.” Such upgrades have included scrubber relief valves, a high-pressure reactor feed pump and a methanol feed pump.
Continuous equipment improvement is at the heart of maintenance activities at Kingsport, stresses Overbeek. Efforts include a Six Sigma program looking at the use of pumps in one processing area. Already the site has achieved a huge improvement in the mean time between failures on its centrifuges — increasing it from two weeks to nine months.
Online condition monitoring also is an important consideration. “It depends on the equipment. If you are going to buy a $13-million compressor then you will use online monitoring. If it’s a $500,000 pump, you probably won’t. You would put this on an inspection route and get it checked three or four times a year by the four-man inspection team that does routine monitoring around the plant. The point here is that the online monitoring has to be able to pay for itself,” he notes.
As Oberbeek suggests, the push is on for suppliers to produce ever more versatile, cost-effective tools for maintenance engineers.
One example is the Spi-VR hand-held data collector from AV Technology (AVT), Stockport, England, that was originally developed as a vibration analysis tool. Its ability was highlighted in December when a European petrochemical plant developed a problem with one of two pumps supplying lube and control oil to a high-speed turbine-driven compressor. The compressor is monitored every five weeks as part of the site’s vibration-based condition-monitoring regime. Using the Spi-VR, personnel noted a step change, about three times the usual amplitude, at the pump’s drive end. By entering this information together with bearing make and model details into the condition-monitoring software program, it was possible to identify the problem as being with the bearing. The pump was taken out of service and dismantled; although the bearing didn’t feel particularly rough, when it was split deep pitting was found in the inner race.
Early detection of the pump’s developing bearing problem resulted in the need to replace only the bearing itself and a quick turnaround. If it hadn’t been detected, more serious damage would have occurred, with increased repair costs and extended machine downtime.
Figure 3 -- Broader capabilities:
Now the Spi-VR has been expanded to handle additional condition-monitoring critical data such as oil analysis, acoustic emissions and thermography information (Figure 3). The company hopes to lauch the device on the U.S. market later this year.
Another company helping plants tackle LCA and LCC is Emerson Process Management, Austin, Texas, which has already clocked up two notable successes in France in the early months of 2009.
The first is at Solvay’s largest plant at Tavaux. The productivity of its maintenance department has risen by 10% to15% following the installation of Emerson’s AMS Suite predictive maintenance software to better manage field devices. Plant staff were looking for ways to capitalize on diagnostics as the total number of devices at the plant increased to near 15,000 — more that 20% of which are complex instruments.
“During the start up of the Epicerol production unit, the process to produce Epichlorohydrin from glycerine, Emerson AMS Device Manager ensured the complete automation system, including DeltaV, was configured right the first time, allowing us to save valuable time during setup. AMS Suite is our daily tool for identifying, standardizing, configuring instruments and saving reference values,” says Giacomo D'Andrea, service manager of automation/instrumentation and electricity.
Chlorine service forms a critical part of the plant and Solvay is using Emerson AMS Valvelink, a snap-on application to AMS Device Manager, to monitor control valves. These valves are fitted with Fisher Fieldvue DVC6000 digital valve controllers, which enable a partial-stroke test to be performed every month without shutting down the plant or bypassing the valve. Partial-stroke testing enables higher reliability of the valve and reduces the need for full testing. The procedure already has successfully detected an anomaly on a valve that is critical for the unit, allowing plant personnel to address the issue before plant upsets occur.
Emerson’s second success in France has come at the Total Petrochemicals site at Carling Saint Avold, where a Smart Wireless condition-monitoring system has been installed. It provides new temperature-measurement data, enabling Total to calculate changes over time in wall thickness of a boiler that supplies steam to a cracker.
Total engineers wanted to introduce new temperature-measurement points to help them better understand the condition of the boiler and anticipate when it might need to be replaced. By measuring the boiler walls’ internal and external temperatures and identifying heat loss, it’s possible to calculate the material’s resistance and infer its thickness.
“Our plant is more than 30 years old,” says Jerome Uszes, electricity control and regulation maintenance manager. “With the rising cost of copper and ageing existing wiring — corrosion, infiltration, armature degradation — finding alternative methods to carry data throughout the plant is becoming essential.”
Wireless connection of the additional measurement points eliminated the need to install around 1 km of new wiring, notes Emerson. Another benefit has been less need to move personnel into and around the at-risk areas, it adds.
This year also has seen new cooperative efforts between vendors to leverage each other’s maintenance technologies.
For instance, Rockwell Automation, Milwaukee, Wis., and Endress and Hauser, Reinach, Switzerland, are jointly introducing tools that allow faster system engineering, reduced risks and better protection of plant assets. The integration between Endress and Hauser’s field devices and Rockwell Automation’s Plantpax process automation system uses open, standard technology at every level. This, they say, cuts the time necessary to engineer a system to minutes while completely eliminating the need for special training on system setup. The tools also provide easier access to instrumentation diagnostics that always have been available at the instrumentation level but seldom used due to heavy engineering requirements.
With these extended diagnostic capabilities, operations and maintenance personnel are better able to monitor device performance, identify faults and take corrective actions for increased operational performance, say the firms.
A second tie-up is between Yokogawa Europe, The Hague, The Netherlands, and Rovsing Dynamics, Copenhagen, Denmark. The latter’s OPENpredictor for machinery health prediction now will be offered as an integrated part of Yokogawa’s VigilantPlant industrial automation offering. This link-up is said to provide a comprehensive solution to achieve what the two firms describe as best-in-class asset availability. Integrating dynamic operational data with predictive maintenance information, OPENpredictor condition-monitoring solutions offer automated fault diagnostics and predict lead time to inspection for rotating machinery.
Such business critical information helps users improve process uptime through the minimized downtime of critical machinery, thus increasing revenue while reducing operational risk and cost, they say.
Motors abound at plants but purchasing decisions too often don’t take into account LCC. However, it may be an apt time for a rethink, counsels an article in a recent issue of Baldor Solutions (http://www.baldor.com/support/literature_load.asp?LitNumber=Solutions1208), the in-house magazine of motor and drives maker Baldor Electric, Fort Smith, Ark.
It points out that as part of former President Bush’s Energy Independence and Security Act of 2007, new regulations will come into force on December 19, 2010, to improve the efficiency of industrial electric motors. Provisions will require 201–500-hp motors to have minimum energy efficiencies and for the first time will mandate efficiencies for 1–200-hp motors, which are popular for close-coupled pumps.
Baldor notes that the purchase price of an industrial motor is only about 2% of what users ultimately spend. Energy accounts for 97% of the total expense. So, while the initial purchase price of a higher-efficiency motor may be greater, it will recover the costs within six to 12 months. The savings in electricity will continue year-after-year over the entire life of the motor. Thus, evaluating such a motor’s LCC should make the purchase decision easier. As the article asks: “While the new act doesn’t take effect until 2010, the question is why wait?”
Seán Ottewell is Editor at Large for Chemical Processing. You can e-mail him at email@example.com.