The demand for corrosion management in chemical facilities has increased because of the high risk of corrosion and the severity of events, which could harm life. Corrosivity can be significantly impacted by even little changes to the process. Asset integrity may suffer from changes in flow rates or product specifications and, if left unchecked, could cause unplanned outages and under-utilisation of the facility. Continuous corrosion monitoring offers the granularity, accuracy, and reproducibility that traditional periodic monitoring methods such as manual inspection do not. Using these traditional methods mean it is impossible to link corrosion incidents to asset integrity, which leads to chemical operators acting reactively rather than proactively.
New technology, like fixed asset integrity sensors, can be easily retrofitted to the facility, enabling plant processes to be optimised. Sensor models, such as the Rosemount™ ET310C, send asset integrity information by way of wall thickness readings directly to the integrity or corrosion engineer’s desk.
Traditional Corrosion Management
Traditional corrosion management techniques use tools such as handheld ultrasonic thickness gauges, which are taken by a technician to the location for measurement on a periodic basis. This method is prone to error, through misconfiguration in the tool, operator error, or uncertainty and inconsistency between measurement location. Clearly, highly accurate and repeatable measurements are key to understanding asset health at any given time.
Another corrosion management technique, Integrity Operating Windows (IOWs), is widely used, whereby process parameters are kept within tolerable limits thereby theoretically eliminating corrosion risk, amongst other things. Although this is logical theoretically, in practise process parameters do indeed change, and especially if the IOW is violated excessively, then corrosion can occur incredibly rapidly, and the method offers no quantification for damage to the equipment.
Rosemount Wireless Permasense Sensors for Continuous Corrosion Monitoring
Utilising permanently mounted ultrasonic sensors measuring wall thickness and employing wireless data is already best practise in the refining industry. The sensors are simple and cost-effective to deploy at scale and provide a quality and frequency of data that is otherwise unavailable. The data informs a wide range of operational decisions due to its sensitivity to small changes in wall thickness, robustness to extreme plant conditions, and extended battery life enabling reliable operation over the entire cycle between turnarounds. Data is transferred using WirelessHART® communications to the end users’ desk, allowing frequent, reliable, and safe wall thickness monitoring.
Corrosion Monitoring System
Recent developments, such as the Rosemount ET310C sensor, mean that sensors can be deployed across the entire chemical facility across any metal, monitoring continuously the asset integrity. With best-in-class repeatability and resolution in the measurement, this allows informed decision making about the process. Sensors are deployed in under five minutes making retrofit installation trivial, and data is retrieved immediately using WirelessHART data delivery.
Data retrieved is fed into Plantweb™ Insight, an industrial analytics solution, which offers instant visibility to key assets, enabling better and faster decisions to digitally transform operations. Plantweb Insight delivers known solutions for known problems in an easy to interpret manner. With pre-packaged analytics focusing on the health monitoring of plant assets, the corrosion software applications give end users the ability to monitor both the risk and impact of corrosion in their plant. A range of analytics supports abnormal situation identification to mitigate safety related incidents, as well as managing routine maintenance and turnaround scope and schedule.
Best quality and reliable measurements are key when it comes to predictive maintenance. Built-in tools allow end users to see accurately the point of retirement of the asset or piping, allowing early replacement scheduling, and consideration of metallurgy for future corrosion resistance. Wall thickness data can be combined to correlate periods of increased corrosion with process data, allowing operators to tweak the process to eliminate corrosion risk, or better plan future maintenance activities.
Online non-intrusive corrosion monitoring is already best practice in the refining industry, and recent advances mean that the same technology is now being rapidly adopted across chemical processing facilities. With the availability of data-to-desk monitoring systems that provide previously unachievable quality and frequency of online wall thickness measurements, engineers and inspectors have demonstrated the ability to know the current condition of the equipment at any point in time with no additional maintenance or costs since the system was installed. The quality and frequency of the measurements enables variations in corrosion rates to be detected, measured, and acted upon while the plant is operating.