Capturing Process Data Without Process Penetrations: Non-Intrusive Instrumentation Delivers Flexibility

Summary

Sometimes the original designers involved in a process overlook opportunities to employ critical process measurement to optimize control or solve a problem. This can happen after a process upgrade or some other type of modification, such as a debottlenecking project.
 
Installing a traditional intrusive instrument can mean a costly retrofit to add a process penetration, calling for a shutdown and equipment modification. The same might be necessary if an existing instrument fails in place, with operators continuing to run without the desired data until the problem can be resolved.
 
This doesn’t have to be the case. New technologies make reading some process variables and equipment conditions through metal or plastic pipe surfaces or tank walls possible, all without a process penetration. This provides flexibility to add a new measurement point without the need for a shutdown, pipe draining or decontamination—and potentially additional work permits for cutting, drilling, welding or other process intrusion—to solve a problem.
 
Let's examine four non-intrusive technology families and where they are particularly suited to providing missing process data. Emerson’s offerings in this area include:

• Flow: Flexim Clamp-On Ultrasonic Flow Meters
• Temperature: Rosemount X-well Technology
• Condition monitoring: Rosemount 708 Wireless Acoustic Transmitter
• Corrosion and erosion: Rosemount Wireless Corrosion and Erosion Transmitters and Rosemount SAM42 Acoustic Particle Monitor.

 Practical advantages

These technologies are designed to be installed on the outside of piping systems, or they can also be attached to larger vessels and equipment such as boilers. They share many common advantages:

• Quick installation or servicing is possible while operating the process, unit or entire facility.
• Flexibility to obtain readings in many applications and environments, with easy relocation as necessary.
• High degree of universality allows for simpler selection and specification.
• No compromise on measurement reading quality, meaning no sacrifice of precision or reliability.
• No additional safety concerns because the potential for leak points and other hazards is eliminated.
• Low total cost-of-ownership as fewer instrument types means fewer spares and simpler maintenance.
• Native WirelessHART option on most of these instruments eliminates wiring and increases portability, and an Emerson Wireless 775 THUM Adapter can be used with those that don’t have this feature.
• New readings can replace data normally captured infrequently via manual inspections.
• Non-intrusive instruments can be specified without using costly alloys since there are no wetted parts.

Expedite upgrades and turnarounds

Whether related to maintenance or improvement, shutdowns halt production. Such events are typically thoroughly planned and scheduled, but plant personnel must prepare for the unexpected. Non-intrusive instruments can substitute for crucial pieces of instrumentation if those are not available on time since they are easy to install and quick to deploy, allowing production to resume quickly (Figure 1).

Minimize manual inspections

Many facilities find it difficult to eliminate all manual operator rounds. Some always remain necessary, and operators may have upgraded to tablets and laptops from clipboards, but rounds are time consuming, expose personnel to potential dangers, and in some cases aren’t effective.
 
Many routine inspections can be automated, freeing up operators to do higher-value tasks. A Rosemount 708 Wireless Acoustic Monitor mounted on a steam trap or pressure relief valve (PRV), (Figure 3) can indicate to maintenance if it is leaking, losing valuable steam or stuck in one position.

No downtime needed

Replacing most instruments or sensors often requires a process shutdown, creating the potential for safety and environmental incidents since the products involved may be hazardous. Restarting the process when finished is also a prime opportunity for upsets and incidents. Consequently, managers insist on seeing economic justification for a shutdown.
 
When using non-intrusive instruments, it is much simpler to justify the value of improved situational awareness, particularly when installation is far less costly with no loss of production (Figure 4). Technicians may need to remove some insulation and dress the mounting surface, but none of these tasks compromise containment.

Simplify troubleshooting

Troubleshooting a process upset or other lapse of product quality often calls for additional measurements to evaluate possible solutions. Non-intrusive instruments make this much easier. For example:

• A Rosemount 708 Wireless Acoustic Monitor attached to a pressure relief valve on a reactor can report the number and duration of overpressure incidents.
• If product or intermediate flow is in question, adding a Flexim Clamp-On Ultrasonic Flow Meter can verify the value.
• Where an out-of-spec feedstock has serious corrosive characteristics, placing a few Rosemount Wireless Corrosion and Erosion Transmitters at critical points can quantify resulting metal loss (Figure 5).
• If an unmeasured temperature seems out of range, a Rosemount X-well Technology instrument can provide an extra point of measurement.

Solve maintenance challenges

Many extreme applications present costly challenges, demanding exotic materials to withstand corrosion or high temperatures. Where conventional instrumentation has significant disadvantages due to challenging conditions, non-intrusive options are more desirable.
 
For example, a poorly designed thermowell extending into a pipe will suffer vibration fatigue due to wake shedding and likely fail, requiring extraction. Rosemount X-well Technology can replace the conventional installation, either permanently or temporarily, and provide a temperature reading without concern for vortex-induced vibration.
 
If a new feedstock contains erosive solids, the primary element of a conventional differential pressure flow meter can be damaged quickly. A Flexim Clamp-On Ultrasonic Flow Meter can replace the existing unit and not suffer from erosion (Figure 6). Monitoring the larger effects of erosion calls for Rosemount Wireless Corrosion and Erosion Transmitters to measure metal loss.

Facilitate process changes

Over time, operators may realize that some instrument locations are not best suited to provide critical variables. Fortunately, it is highly practical to relocate non-intrusive instruments, particularly those that use WirelessHART connectivity.
 
Even the previously mentioned Flexim flow meters can be dismounted and relocated without any effect on the process, although supporting signal wiring will also need to be rerouted. To eliminate this wiring, an Emerson Wireless 775 THUM Adapter can be added to provide WirelessHART connectivity.
 
It is evident how non-intrusive measurement instruments provide ease of use, safety, flexibility and
reliability benefits in a wide range of common use cases. With the widest range of non-intrusive measurement technologies, Emerson provides these solutions to optimize processes and maintenance efforts, while reducing costs.
 
_{All figures courtesy of Emerson}