Control Engineering magazine has a great article and 8-minute video, A Straightforward Maintenance Strategy Yields Improved Plant Performance, featuring Monsanto Muscatine’s use of technology to move from reactive to predictive maintenance to improve output and reduce costs.
Their use of smart field devices and control valve positioners provided important diagnostic data to the reliability engineers. This use and quantification of business results earned the facility the 2012 HART Plant of the Year Award.
The article highlights their use of the reliability-based predictive technologies:
One of the pivotal changes in Muscatine’s operation happened in 2006 when Joel Holmes, site electrical reliability engineer, received a standalone Emerson AMS unit from another Monsanto plant. Having access to that unit enabled him to explore some of the capabilities of a more sophisticated maintenance strategy using diagnostic information gathered from field devices using HART Communication and Foundation fieldbus protocols.
Given the facility’s extensive population of maintenance-intensive valves and instrumentation, this was an area where Holmes felt that improvements in reliability would have the largest impact on overall plant performance. Part of the process of integrating his new maintenance tools with the work processes involved assigning a criticality value to the instrument assets in each process unit. Those that could impede production were given the highest priority for monitoring.
The facility has more than 3,200 instrument assets, including transmitters and control valve positioners. More than 700 of these use HART and Foundation fieldbus digital communications connected with the plant’s AMS Device Manager. The goal is to use the diagnostics in identify issues before they impact production. The fix can then be applied in a planned, controlled way instead of a “drop everything”, reactive way.
Assets are categorized by their criticality:
As Holmes described the process, “We utilize an A, B, or C letter designation to denote asset criticality. The highest criticality ranking is an A, with the lowest criticality ranking being a C. Keep in mind, A-ranked critical devices will receive the most attention since their performance is crucial to the on-stream time of the production system whereas C-ranked devices may, in many cases, be allowed to run till failure since their impact to the production system is minimal or they have in-line spares.”
AMS ValveLink diagnostics are performed on the control valves to identify ones in need of maintenance. In an earlier post, Diagnosing Valve Performance Issues, we highlighted several of control valve issues, which these diagnostics could help find.
The work processes that were designed to maximize the use of these predictive technologies also helped to improve communications and collaboration between plant maintenance, production, and reliability teams.
Congratulations to Joel and the plant staff on their award and recognition of their effective reliability practices!