Treat sulphuric acid and oleum as a range-specific measurement duty
Rhosonics describes using speed of sound and temperature to determine sulphuric acid and oleum concentration in different calibrated ranges. This matters because the acoustic relationship is not a single unrestricted mapping across every possible concentration. The process range, temperature and required reporting basis must therefore be established before configuration.
Range selection is fundamental
Provide the normal and excursion concentrations, whether the process crosses between acid and oleum ranges, and the reporting units. PMA can then review the appropriate manufacturer calibration basis.
Materials and temperature require review
The analyser and every wetted component must be compatible with the actual concentration and temperature, including start-up, shutdown, dilution, cleaning and upset conditions.
See the measurement in its process context
Application planning includes the surrounding process, safe access, representative sampling and verification—not only the analyser itself. PMA reviews these conditions together before recommending a measurement arrangement.
Three decisions for H2SO4 or oleum measurement
The intended operating window and response must be explicit.
Select the calibrated window
State minimum, normal and maximum concentration and temperature. Do not assume that a calibration outside that window will remain unique or accurate.
Choose a representative point
Review mixing, dilution, recirculation, gas, crystals, temperature gradients and whether the pipe remains full at the proposed location.
Set the verification rule
Define the approved laboratory method, safe sample point, comparison frequency and action when online and reference results disagree.
Sulphuric acid and oleum measurement pathway
- Define the product. Record grade, concentration basis and expected contaminants.
- Confirm the range. Match the operating window to a manufacturer-supported calibration.
- Review compatibility. Check sensor, seals, valves, pipework and sample system.
- Survey the measurement point. Confirm mixing, full pipe, temperature and isolation.
- Commission safely. Compare representative samples across the approved range.
- Govern changes. Reassess calibration after process, grade, material or temperature changes.
Evidence to collect
Collect time-aligned concentration results, temperature, process grade, dilution or addition events and reference laboratory values. Keep the calibration range and units visible in records so results from different regimes are not combined incorrectly.
Limits, compatibility and safety
Concentrated sulphuric acid and oleum are highly hazardous. Measurement selection does not replace containment, compatible materials, ventilation, emergency planning, PPE, training or site process-safety systems. A reading outside the validated range should not be treated as a reliable concentration result.
Frequently asked questions
Can the analyser cover acid and oleum with one range?
Do not assume so. Rhosonics identifies different concentration ranges. PMA should review the exact window and manufacturer calibration before specifying the duty.
Why is temperature measured?
Speed of sound changes with both composition and temperature. The model uses temperature compensation within its defined calibration basis.
What happens after dilution?
Mixing and temperature may take time to stabilise. The measurement point and control logic should account for transient conditions before action.
Does the analyser replace laboratory analysis?
No. Reference analysis remains important for commissioning, periodic verification and investigation of unexpected results.
Sources and engineering review scope
PMA will review the acid or oleum grade, calibrated range, temperature, compatibility, installation point, sample method and control consequence. This page is application guidance, not a substitute for a site survey, chemical compatibility review, risk assessment or manufacturer-approved configuration.
Related analyser range
The 8500 Series is the relevant one-component ultrasonic concentration analyser range for defined H2SO4 and oleum duties.
View the relevant analyser range.
Define your sulphuric acid or oleum range
Provide PMA with the concentration window, temperature, grade, materials specification, pipe details and reference method.