Inside Information: Corrosion
Imagine plant-wide pipe and vessel integrity displayed on your risk profile dashboard. April 24th is the Corrosion Awareness Day by the World Corrosion Organization so like in previous years, let’s examine how to make the work of corrosion and integrity engineers easier with permanent sensing. Continuous corrosion monitoring with permanent sensors has become increasingly common in refineries the past several years. Leading chemical plants are now also adopting continuous corrosion monitoring. What is the recommended practice for chemical plants? Here are my personal thoughts:
Corrosion Risk Reduction
Corrosion and subsequent loss of containment is a known risk in the chemical industries handling acidic and basic/alkaline fluids in the form of feedstock, reagent, catalyst, solvents, or as a cleaning agent in pipes as well as in process equipment like reactors, distillation columns, and storage tanks. The consequences of a loss of containment can be very serious as the chemicals may also be toxic and flammable. Incidents are costly. Traditionally plants have relied on portable UT testers to inspect remaining wall thickness to uncover weaknesses before loss of containment occurs. However, manual inspection is time consuming so it does not get done frequently enough so loss of containment still occurs. Manual UT testing is also less accurate because the measurement spot is not exactly the same every time so corrosion rate test results are inconsistent. Manually handling insertion corrosion coupons have another set of challenges. In short, manual work processes are a challenge.
“Digital” transformation is about automating manual work processes
Monitor the Inside of Your Pipes and Vessels
Automating manual data collection is the foundation of digital transformation of work. That is, installing sensors instead of integrity engineers having to walk about with portable testers or pulling coupons. The upstream oil & gas industry, refineries, and the petrochemical industry have been using permanently installed corrosion sensors for several years. A permanently installed corrosion sensor sends data twice a day or more, on the timescale of corrosion, this is continuous and real-time. These more frequent updates overcome the problem of yearly or monthly inspection. Since you don’t know if or when the corrosion rate may worsen, corrosion sensors must be left in place, not moved around because data may be missed just as you need it the most. That is, the recommendation is to permanently install corrosion sensors.
Chemical plants are now installing permanent corrosion sensors
Continuous Permanent Sensing
As is often the case in “digital” transformation, transforming work is about deploying sensors for automatic data collection and software for automatic data interpretation. Corrosion management requires specialized corrosion sensors and corrosion analytics software. Don’t attempt corrosion monitoring using general purpose data analytics.
Ultrasonic Thickness (UT) Corrosion Sensing
Sensors is where monitoring systems touch the physical reality they help manage; cyber-physical systems. The recommendation is to use advanced corrosion sensors which are non-intrusive and wireless. This makes them very easy to install for I&C technicians. They can be installed while the plant is operating, while the production is running.
Chemical plants are generally lower capacity than refineries. Therefore chemical plants have smaller diameter pipes. Also thinner pipe walls. Because of the corrosive chemicals the pipes are often made from exotic materials – but that doesn’t mean they don’t corrode. Corrosion sensors used in chemical plants must take this into account.
The recommendation is to use the WirelessHART technology for the wireless sensor network (WSN) infrastructure in the plant for several reasons. For instance, it is an industrial standard protocol (IEC62591) and use standard radio (IEEE802.15.4) making it a low-risk investment compared to many other wireless solutions using non-standard proprietary radio technology which therefore carries risk. WirelessHART is peace of mind. WirelessHART also automatically converts to HART-IP and thus integrates with the same Intelligent Device Management (IDM) software as the plant’s wired 4-20 mA/HART devices making work easy for I&C engineers. That is, all WirelessHART devices can be configured and diagnosed centrally from the same single tool. The same tool as the wired devices. Most other WSN cannot do this. Industrial grade sensors for many other measurements such as differential pressure etc. as well as wireless adapter for wired 4-20 mA/HART instruments share the same WirelessHART infrastructure but are not available for other WSN.
Remember, corrosion is a slow process so you don’t need one second update period for the UT measurement. Once or twice a day is sufficient. This has the added benefit of reduced data communication bandwidth and data storage volume requirements and also extends battery life for wireless devices.
A sample a day keeps corrosion at bay
Corrosion Analytics
The software is a critical piece of the corrosion management (just like for all other operations management automation systems). The recommendation is to use software purpose-built for corrosion monitoring, advanced signal processing readymade with all the subject matter expertise built in. This makes corrosion management easy for the integrity engineers. A corrosion management system provides detail data for each monitoring position, such as:
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Ready apps make light work
At the highest level in the corrosion analytics software is a simple overview dashboard for corrosion risk in the plant. From there the integrity personnel can click-through to ever greater levels of detail.
The software can run in the cloud or at the edge, on a server on-premises. That is, there is no need for cloud or associated connection to the internet. This can make deployment easier. Even with the corrosion software running on-premises, it can still be made visible on-the-go from mobile devices across the internet.
System Integration and Data Management
These days it is getting increasingly common to integrate the various operations management automation systems around the plant to display them on dashboards such as for risk profile, historize in a data lake, or into even high-level analytics such as for correlation with fluid properties or production rate. Such integration through proprietary “API” or protocols would be impractical. The most interesting fact is that there are much better ways than coding APIs. The recommendation is therefore to use corrosion analytics software which supports the OPC-UA standard (IEC62541) software interface and Modbus/TCP, the native I&C protocol supported in most plant automation systems. OPC-UA and Modbus/TCP makes it easy for the I&C engineers to integrate the corrosion analytics software with other software and systems, that is, makes it easy to stream the corrosion data to other systems and software. Data made available should include:
?Data integration as easy as OPC
OPC-UA is the best technology option for data integration and data management because of important feature such as automatic server discovery, structured information model (IM) and browsing, comprehensive metadata including status, point-level granularity security, client-server and pub/sub communication, transparent integration with OPC Classic, and cloud support. Plus OPC-UA is already widely supported in automation systems so OPC-UA makes it easy for I&C engineers to integrate all these systems without coding or scripting.
For older systems not yet supporting OPC-UA, such as legacy historians, Modbus/TCP data integration is another option.
The corrosion management system works alongside various other operations management automation systems fitting nicely with the NAMUR Open Architecture (NOA).
Action Plan: Corrosion Management
Know what is going on inside your pipes and vessels. “Digital” transformation (DX), “Internet” of Things (IoT), smart plant, Industry 4.0, industrial transformation, or whatever you prefer to call it is all about industrial automation. This includes automation of manual tasks such as collection and interpretation of corrosion data. Here’s an action plan for which you can allocate a person responsible, date of completion, budget, and other resources:
“Digital transformation” means a new era in automation. Lead the way. Schedule a meeting with your integrity manager and I&C team for the 24 April Corrosion Awareness Day or today. Share this essay with your integrity manager now. And remember, always ask vendor for product data sheet to make sure the software is proven, and pay close attention to software screen captures in it to see if it does what is promised without expensive customization. Well, that’s my personal opinion. If you are interested in digital transformation in the process industries click “Follow” by my photo to not miss future updates. Click “Like” if you found this useful to you and to make sure you keep receiving updates in your feed and “Share” it with others if you think it would be useful to them. Save the link in case you need to refer in the future.
Advisor to Manufacturing Executives | Future of Industrial Work, EHS, and Knowledge Management
1 年Existing standards and our industry failure experience are great places to identify “bang for the buck” and deliver proof of concept success to initiate the move into this direction. Supporting inspections teams and providing the justification Operations needs to prioritize and repair accordingly to avoid unplanned, and often dangerous events. Great share Jonas Berge