Gulf Chemical & Metallurgical Corporation (Freeport, Texas), a subsidiary of the Eramet Group, is a recycler of spent petroleum catalysts and a leading producer of ferroalloys. The company applies hydrometallurgical and pyrometallurgical operations to recover molybdenum, vanadium, nickel and cobalt for reuse by major catalyst producers and steel manufacturers. Embarking on the road to improved equipment reliability represents a key aspect of a concerted strategic initiative for Gulf Chemical. The introduction of wireless technology and additional support has yielded successful outcomes for its facility.
A strategic mission to achieve sustained reliability objectives for rotating machinery and, in turn, optimize cost avoidance prompted Gulf Chemical to audition and then expand a wireless condition monitoring system. The process began in late 2007 with a limited "test trial" at the facility, which ultimately led to the deployment of an online system to monitor dozens of critical assets. Total documented savings exceeded system cost in the first year.
Trial Period for the System
The test trial focused on three problematic high-output fans. Initial first-pass troubleshooting indicated trouble linked to the internal design of the fans' base structure, which was apparently causing repeated fan failures. A massive (and costly) redesign of each base was considered inevitable.
During the trial, fan operating parameters were monitored using a wireless monitoring system. Battery-powered, eight-channel units were mounted directly on machines to collect data on acceleration, velocity, temperature and bearing condition, including spectral data for automatic upload for viewing and analysis. In this case, vibration data was analyzed, and it was deduced that the base structure was not the source of the problem. Instead, cavitation in the ducting was discovered to be the root cause of the premature bearing (and fan) failures. This verified conclusion eliminated any need for a redesign of the fan base and any outlay of associated capital.
System Expansion
The success of the trial supported the decision to expand the condition monitoring process throughout the facility. The critical assets now under constant online surveillance include dozens of cooling pumps, hydraulic pumps, scrubber pumps, high-volume fans and blowers, paddle mixers, electric motors and cage mills. An online system constantly monitors all of them.
The system enables early fault detection and prevention, automatic advice for correcting existing or impending conditions, and advanced condition-based maintenance for improved machine reliability, availability and performance.
Each system is equipped with either 32 or 16 dynamic analog signal inputs and eight digital channels. The dynamic signal inputs are configurable for a variety of sensors to measure acceleration, velocity, displacement, temperature and other parameters. Each input can be configured for ICP (accelerometers) and proximity probes. The eight digital channels may be used for measuring speed, trigger or digital status (for example, indicating when a measurement can take place). Several measurement points can be attached to one channel and both AC and DC measurements can be taken on the same channel.
Individual conditions for warning and alarm can be established and set for each point with levels governed by machine speed or load.
How the System is Implemented in the Facility
The system monitors multiple components in the designated critical assets. For example, the system's dual sensors (vibration and temperature) applied to an overhung fan monitor two motor bearings, two shaft bearings and one tachometer using eight analog channels and one digital channel. Data is transmitted wirelessly within a 100 ft radius to a strategically located wireless network point in the plant.
Each sensor in the drive train has a predetermined warning and caution threshold designed with a simple visual "stop light" indicator (red for warning, yellow for caution and green for normal). When thresholds are exceeded, the system's graphical interface (on LCD screens) turns the appropriate color (red or yellow) in the reliability offices and the operations digital control center. An overview screen pinpoints the source and allows reliability technicians to access a photo layout of the actual asset with stop light indicators showing temperature and overall IPS parameters. This allows the user to quickly identify the part of the rotating assembly showing problems.
All relevant parties are quickly briefed in a timely manner, regardless of their location. Simultaneous email alerts are relayed to the supervisor and maintenance foreman for the area where the equipment is operating and, similarly, to the reliability and maintenance superintendents.
After the online data is confirmed using a handheld monitoring unit to rule out the possibility of incorrect data, the reliability department performs both a complete amplitude and phase analysis on the failure and creates a work order to maintenance with the appropriate actions needed to address the problem. Once corrective work is complete, data is verified about the adequacy of the repair and to ascertain that the initial failure was not masking other issues within the system.
The total time elapsed from the initial warning to repair and verification is usually less than 12 hours, depending on the size of the equipment and the severity of the problem.
The system's software serves as the primary HMI for asset failure notification and its simplicity has made life easier for management and the workforce. Simple visual indicators allow operators without any experience in vibration monitoring to identify deviations from normal operating conditions. The operator clicks on an auto analysis tab and reads the analysis report to learn what is wrong, and then notifies maintenance staff for remedial action.
Promoting peace of mind, the system's unique built-in hardware auto-diagnostics continuously check all sensors, cabling and electronics for any faults, signal interruption, electrical shorts or power failures. Any malfunctions will trigger an alarm and, in the case of power failure, the system automatically restarts when the power returns.
The system has fully supported condition-based maintenance objectives in the facility and accrued measurable economies by significantly reducing the time and manpower required to analyze a deviation from operating norms.
The system has helped replace the need for multiple employees to run routes, shortened the time required to analyze data and minimized risks of potential equipment failures due to excessive time between notification and correction. In addition, mechanics in the field can call on a radio or cell phone to receive accurate data about repairs within seconds without waiting.
For example, the facility has a bag house blower whose proper functioning and levels of throughput are necessary for an environmental system at the facility to meet U.S. government regulations. The wireless online condition monitoring system was able to detect an early failure in the blower in time to schedule repairs during a routine maintenance stoppage without interrupting production. Estimated cost avoidance was approximately $42,000, which would have included costs for materials, rebuilds from total degradation, overtime and production downtime.
Conclusion
Significant strides have been made in enabling wireless online condition monitoring technology to meet the evolving needs in the marketplace. Universally cited benefits include the 24/7 capability to monitor equipment and upload data for analysis around-the-clock; a centralized data repository accessible to management and staff regardless of their locations; more timely data on machine conditions and minimized investment, further eliminating any need for typically redundant hardware, software and labor.
The real-world "drivers" for the growing interest in such condition monitoring systems include the ability to network across multiple sites; advances in services and reporting via the Internet; robust analysis software and its ability to accept data received from multiple locations and different equipment over different protocols; and the demand for outsourced services and expertise.
For Gulf Chemical, top management and reliability staffs understood at the outset that a proactive approach toward maintenance, in partnership with an experienced and innovative supplier, can generate improved performance, reliability, economy and service life of critical assets.
Pumps & Systems, December 2009
Casey A. Connolly is the manager of continuous improvement & reliability for Gulf Chemical & Metallurgical Corporation, and Frank Mignano is senior account manager at SKF Reliability Systems.
Tags: December 2009 Issue , Instrumentation/Controls , Pump Industry Technology |
