Emerson FLEXIM FLUXUS Enables Non-Intrusive Sulfuric Acid Concentration Measurement in Sulfuric Acid
Time:2026-08-25 Browse: 0
August 25, 2026
Continuous sulfuric acid concentration monitoring is an important part of process control in sulfuric acid production. In sulfur-burning acid plants, interruptions in concentration measurement can make it more difficult for operators to identify process deviations in time, potentially affecting product quality and plant operation.
To address the challenges associated with conventional contact-based measurement, Emerson FLEXIM offers a clamp-on ultrasonic measurement approach based on its FLUXUS technology. The solution enables sulfuric acid concentration to be monitored from outside the process pipe without direct contact with the acid.
Challenges of Sulfuric Acid Concentration Measurement
Sulfuric acid production involves demanding process conditions. Depending on the process section and operating conditions, concentration measurement equipment may be exposed to corrosive media, elevated temperatures and deposits.
Several factors can affect the long-term performance of conventional contact measurement technologies.
1. Highly Corrosive Medium
Concentrated sulfuric acid is highly corrosive. Contact sensors installed directly in the process medium require suitable wetted materials and careful maintenance.
Long-term exposure can contribute to corrosion, deposits or sensor degradation, potentially resulting in measurement drift or instrument failure.
2. High Temperature
Temperature is another important factor in sulfuric acid concentration measurement.
Elevated process temperatures can increase the demands placed on sensor materials and instrument components. Temperature changes can also affect the relationship between physical properties and concentration, making appropriate compensation and process measurement important.
3. Deposits and Crystallization
Deposits or crystallized material accumulating around a contact sensor can affect the transmitted measurement signal.
As deposits increase, the measurement may become less reliable and maintenance or cleaning may be required. For continuously operating plants, maintenance requirements can also mean additional operational interruptions.
4. Leakage and Installation Risks
Conventional contact instruments generally require a process connection or opening in the pipe.
For corrosive sulfuric acid service, every additional process connection needs to be carefully engineered to minimize the possibility of leakage. Installation and maintenance can therefore become important safety considerations.
Emerson FLEXIM's Clamp-On Ultrasonic Approach
Emerson FLEXIM addresses these challenges with clamp-on ultrasonic measurement technology used by the FLUXUS platform.
Instead of placing the sensor directly into the sulfuric acid, ultrasonic transducers are installed on the outside of the process pipe.
The measurement is based on the relationship between ultrasonic propagation characteristics and the physical properties of the liquid. By measuring the ultrasonic signal through the pipe wall, the system can determine process information without direct contact between the sensor and sulfuric acid.
This non-intrusive architecture is particularly relevant for corrosive process applications where minimizing wetted components is desirable.
Key Specifications for Sulfuric Acid Concentration Measurement
According to the application information provided for the FLUXUS solution, the measurement system can be configured for demanding sulfuric acid concentration applications.
Key specifications include:
Sulfuric acid concentration range: 80%–100% H₂SO₄, including oleum applications
Temperature range: -40°C to 240°C
Applicable pipe sizes: DN6 to DN6500
Concentration measurement accuracy: up to ±0.1%
Response time: less than 1 second
Actual performance depends on the specific process conditions, pipe construction, installation configuration and application setup. Engineering evaluation is therefore recommended before selecting the final measurement configuration.
No Direct Contact with Sulfuric Acid
One of the main advantages of clamp-on ultrasonic measurement is that the transducers remain outside the process pipe.
Because the measurement components do not need to be immersed in sulfuric acid, the system avoids direct exposure of the sensor to the corrosive process medium.
This can reduce concerns associated with sensor corrosion, wear and deposits on wetted components.
For sulfuric acid plants, the non-intrusive design can also simplify installation because the pipe does not necessarily need to be cut open to install an inline sensor.
Measurement Without Process Shutdown
Another important consideration for continuous production is installation without interrupting the process.
Clamp-on ultrasonic sensors are mounted externally on the existing pipe. In suitable applications, this allows the measurement system to be installed without cutting the process pipeline or removing the process medium.
This can be particularly useful for operating sulfuric acid plants where stopping the process solely to install or replace a measurement instrument may be undesirable.
The final installation method, however, depends on the pipe material, diameter, wall thickness, temperature and site conditions.
Fast Response for Process Monitoring
Sulfuric acid concentration can change as process conditions change. A slow measurement response may delay the detection of process deviations.
The FLUXUS solution is specified with a response time of less than one second for the relevant application, allowing concentration changes to be monitored rapidly.
When integrated with a plant's DCS or other process control system, concentration data can be used as an additional process variable for monitoring and control.
This provides operators with more timely information without requiring a contact sensor to be installed directly in the acid stream.
Combined Flow and Concentration Measurement
Depending on the FLUXUS configuration, ultrasonic technology can also provide flow measurement in addition to concentration measurement.
Combining flow and concentration measurement within the same measurement platform can reduce the number of separate instruments required for certain applications.
For sulfuric acid plants, this can provide process engineers with additional information for monitoring material movement and process performance while potentially reducing installation space and instrumentation complexity.
Why Non-Intrusive Measurement Matters in Sulfuric Acid Plants
The main value of clamp-on ultrasonic concentration measurement is not simply the measurement principle itself. Its significance lies in how the technology fits demanding continuous-process applications.
For sulfuric acid production, the key considerations include:
Avoiding direct sensor contact with highly corrosive acid
Reducing the number of potential process leakage points
Supporting installation without cutting the existing pipe
Minimizing routine sensor cleaning requirements
Providing rapid concentration feedback
Supporting continuous process monitoring
Offering the possibility of combined flow and concentration measurement
These characteristics make non-intrusive ultrasonic technology an option worth evaluating when a sulfuric acid plant needs online concentration measurement while maintaining continuous operation.
Application Value for Process Automation
Online sulfuric acid concentration measurement can provide useful process information to operators and automation systems.
When concentration data is continuously available, the DCS can use the measurement as part of the plant monitoring and control strategy. Operators can also observe concentration trends and identify changes before they develop into larger process deviations.
For plants where instrument maintenance, process leakage and production interruption are major concerns, an external clamp-on measurement architecture can offer an alternative to conventional intrusive instrumentation.
The suitability of the technology should ultimately be evaluated against the actual acid concentration, temperature, pipe specifications, flow conditions and installation environment.
Conclusion
Sulfuric acid concentration measurement is a demanding instrumentation application because the process can combine corrosive media, elevated temperatures, deposits and strict requirements for continuous operation.
Emerson FLEXIM's FLUXUS clamp-on ultrasonic technology provides a non-intrusive approach in which the transducers are installed outside the process pipe rather than directly exposed to sulfuric acid.
With rapid response, a wide range of pipe sizes and the ability to support concentration and flow measurement in selected configurations, the technology provides an alternative approach for online sulfuric acid concentration monitoring.
For sulfuric acid plants seeking to improve process visibility while reducing the maintenance and leakage concerns associated with intrusive measurement devices, clamp-on ultrasonic technology represents a practical instrumentation option for consideration.
