Maintenance has traditionally been viewed as a cost center in the cement industry. But over the course of decades, it has emerged as a source of profitability, and the key to boosting profit margins. This is not coincidental, as each day of downtime costs a 1 MTPA plant as much as $300,000. Moreover, unplanned downtime can cost even more, requiring urgent sourcing of spares, and adding to the overall downtime of the plant. Until recently, 90% uptime was heralded as the gold standard in cement.
But technologies like artificial intelligence (AI) and machine learning (ML) have made it possible to supersede these numbers, and nail the intended uptime targets with repeatable success. By implementing AI and ML algorithms, plants can predict equipment failures before they occur, allowing for proactive maintenance that minimizes unplanned downtime and maximizes uptime and efficiency in production. Read on to find out how to eliminate unplanned cement plant downtime, and maximize equipment availability beyond the industry standard.
Why downtime matters in the cement industry
In asset-intensive industries like cement, overall equipment efficiency (O.E.E.) is directly linked to the annual production volume of a plant. What’s more, OEE is directly proportional to the availability of equipment, as it is measured as a product of quality, availability, and rate of the asset.
Cement production is a chemically and physically demanding process. Crucial pieces of equipment like the rotary kiln operate under extreme conditions, and are subject to wear and damage caused by heat, mechanical stress, vibration, miscalibration, and other factors. Likewise, they require effective maintenance processes to mitigate unplanned downtime. This is crucial to ensure that the plant can run without disruptions, and achieve maximum production volume.
One crucial aspect linked to cement plant downtime mitigation is the overall cost of maintenance. While minimizing downtime is important, optimizing the annual costs of maintenance carries equal weight, as these maintenance costs start bleeding revenues and tend to offset the losses associated with mitigated downtime.
Root causes of cement plant downtime
Downtime in cement plants is caused by multiple factors, but like in other industrial settings, the Pareto effect is at play here. Some causes of downtime occur more frequently than others. For instance, kiln shutdowns tend to happen more frequently – so much so, that an average plant experiences nine breakdowns per year due to factors like ring buildup and its consequent collapse, and thermal stress on the refectory lining due to axial misalignment or shell ovality. Brick lining failure typically contributes to the highest frequency of kiln shutdowns.
Failure due to wear or damage to electric and mechanical parts like vertical roller mills, roller bearings, motors, kiln drive systems, and reducers can also contribute to cement plant downtime.
Mitigating cement plant downtime: old and new approaches
To mitigate unplanned cement plant downtime, new approaches have been devised over time. Corrective and preventive approaches are most utilized in the industry, although their efficacy remains limited.
Why scheduled and preventive maintenance doesn’t work
While scheduled and preventive techniques are proactive approaches to avoiding unplanned downtime, they usually rely on the operator’s intuition and experience. However, because most plants are using equipment that is three to four decades old, the frequency and magnitude of failures can vary. Aged equipment fails more frequently, and the scope of repair work is also higher. As such, over-maintenance or unprecedented breakdowns are usually unavoidable.
The efficacy of such maintenance routines is also impacted by monitoring and inspection techniques. With manual inspection, it is usually unable to anticipate a failure within the window where corrective maintenance is still possible.
Eliminating cement plant downtime with predictive maintenance
Predictive maintenance makes use of Internet of Things (IoT) sensors to accurately forecast the point at which a piece of equipment is likely to fail. The precision of predictive maintenance varies across solutions, and self-learning systems attain higher accuracy over the course of their deployment. However, some solutions can predict failures with a 95% confidence interval, and even identify the root cause of the expected failure.
Predictive maintenance is currently the most effective approach to eliminating cement plant downtime. It can ingest multiple variables to diagnose and forecast failure modes. For example, tyre migration techniques can be used to continuously monitor kiln shell ovality, and infrared imaging can help determine overheating, thereby helping operators maintain optimal operating conditions. With predictive maintenance solutions, alarming mechanisms can be set to alert the operators of any anomalous conditions, or if a failure is likely to occur within the coming months.
The upside of predictive maintenance over other proactive techniques is that it enables operators to fully optimize the maintenance schedules, and thereby minimizing the cost of eliminating downtime. Once they receive an alert for a likely failure, a repair job can be scheduled just before the breaking point. In some cases, downtime can be planned to conduct multiple repair and maintenance tasks within a single window, thereby minimizing the overall downtime of the cement plant.
What else do I need to eliminate cement plant downtime?
A predictive maintenance solution is just one (albeit, foundational) of the few requirements to achieving zero unplanned downtime. Organizations also need to digitize their maintenance function, keeping the following things in mind:
- Clearly define and document standard operating procedures. When possible, SOPs must be integrated into the control systems. This helps reduce people dependency, and ensures that the plant will attain similar KPIs with new operators and technicians.
- Synchronize your inventory management system with your predictive maintenance solution. This will ensure that the spares required to carry out a work order are available, and your operators don’t need to expedite them at extra costs.
- Define a data-based strategy for driving equipment replacement decisions. In some cases, replacing aged machines can drastically improve the reliability of the overall system, and lower the costs of maintenance for the coming years.
Next steps
Predictive maintenance is the first step to eliminating unplanned cement plant downtime and over-maintenance. It can help operators maximize the OEE of assets at the lowest costs, thereby increasing revenues without increasing the input costs of production. Once a predictive maintenance solution is in place, cement businesses can carry out a maintenance digitization program that will help them realize the complete benefits of predictive maintenance.
Take the first step towards eliminating unplanned downtime, by implementing UptimeAI, an industry-leading predictive maintenance solution for cement plants. Contact us now to get started.