Process Control System Integration: Smart Sensors for Better Reaction Control

Key Takeaways:

• Smarts sensors are a new technology in process control system integration. The instruments incorporate onboard processing and contextualizing of process measurements. 
• When used in industrial reaction processes like those found in chemical and life science fields, smart sensors unlock significant improvements in reaction control, yields, consistency and safety. 
• Smart sensors vastly improve process control system integration, making them exceptional investments for both existing and new applications. 

While you might have come across smart sensors in either your work or home life (as lots of home automation devices are sold under this name), you might not be privy to just how far smart sensors have penetrated into industrial process control system integration.

Take industrial reaction processes, for example. 

Reaction processes are complex applications found in chemical, life science, metallurgical, petroleum and polymer fields, among others.  In a reaction process, a starting mix of chemical ingredients is turned into an entirely different composition, achieved by coercing physical rearrangement of the ingredients’ molecular makeup. 

Reactions take lots of energy, often involve hazardous and volatile compounds, and can be excessively costly when they fail. This is why smart sensors have gained so much attention in these applications. They offer simple reassurance and proactive protection against such failures, not to mention significantly better reliability and overall control.   

What Is a Smart Sensor? 

Perhaps the best way to understand a smart sensor is to compare it to a traditional “dumb” sensor.

An RTD (resistance temperature detector) is a great example. An RTD imposes resistance onto an electrical current flowing through its element, and this resistance measurement can be used to calculate temperature. All computation and processing of that current output is done elsewhere in the system, which leaves lots of room for error. 

Smart sensors are designed to eliminate such errors by relocating a portion of the control loop’s computational activity to the sensor itself. This typically adds a microprocessor and an active transmitter to the sensor, along with additional options such as onboard interfaces, Ethernet or WiFi connectivity, and more. All of these features are what makes smart sensors so powerful when installed as part of a fully-integrated control system. 

Key Features of Smart Sensors

By giving a sensor added intelligence, control functions that are most dependent on the environment around the sensing location can occur where they will be most accurate. In addition, the sensor itself can play a greater role in communicating about and managing risk factors that would otherwise threaten process integrity.  

Bringing such intelligence to the sensor body serves operational goals such as:

• Accurate, adjusted, real-time readings: Smart sensors minimize the low-fidelity portions of a circuit (i.e., resistance) via onboard processors that generate high-fidelity, conditioned and calibrated outputs (i.e., mA) right at the sensors.
• Adaptive process controls: Smart sensors support advanced communication protocols (like Ethernet I/P or HART), which provide additional context to the upstream PLC or DCS as well as remote configuration. 
• Improved yields and consistency: Because smart sensors provide more accurate output readings, process control systems can achieve equally improved product yields and consistency.
• Predictive maintenance: Smart sensors protect overall process continuity, as their self-diagnosing features can detect and notify upstream control systems about drift, alarm states and even impending failures.
• Enhanced safety: Smart process sensors provide a significant boost to process safety, both in providing more reliable measurement of process conditions as well as alarm notifications of faltering device health.     

Applying Smart Sensor Advantages to Industrial Process Reactors

Industrial process reactors are complex equipment systems most often comprised of a central pressure vessel surrounded by multiple support subsystems. Every device in the entire system is a potential source of bad control data, which can cause an ongoing reaction to completely fail. 

Smart sensors directly alleviate risks of bad input through their core features – active control, reliable signaling, uber-responsiveness and deep process control system integration.  

In fact, here are four specific reaction applications where smart sensors excel:

• Thermal monitoring: Temperature monitoring is often the first place where smart sensors are introduced into a reaction process, as issues like poor heat distribution, hotspots and runaway reactions are paramount to catch early. 
• Pressure and gas monitoring: Reactions that change chamber pressures, create off-gases, experience cavitation or generally must be monitored for fast or unideal changes are the next best spot for smart sensors.
• Input composition and analytics: Reactors are notoriously sensitive to out-of-spec feed material and utility services (i.e., density, flow rate, pH, moisture, etc), which many smart sensors can help protect against before beginning reactions. 
• Reaction progress and conversion measurement: Real-time reaction and conversion measurement benefits greatly from smart sensors, especially for multi-element analysis using near-infrared (NIR), UV and spectrographic instruments.

Smart Sensors and Process Control System Integration

To gain the benefits of smart sensors, all you typically need to do is swap out traditional sensors for smart sensor variants, change a little wiring, update controls and networking configurations, and re-commission the system. In most cases, the cost of converting to smart sensors has a payback period measured in months, not years. 

For more details on how you can adopt smart sensor technology in your reaction processes, reach out to us here.