Unlocking Efficiency in Sulfuric Acid Applications: Expert Insights

Welcome to the second in our series of three Q&A blogs where industry experts Kevin Green from Vaisala and Dave Lobach from Rocky Mountain Instrumentation provide answers to questions from our webinar, "Unlocking Efficiency: Refractive Index Insights for Chemical Industry Concentration Applications". The first of our Q&A blogs is also available: "Prism wash systems and refractometers in chemical applications."

If you missed the live webinar, you can still watch the recording.

In this second blog, Kevin and Dave focus on the nuances of refractive index measurement in sulfuric acid applications. Please find a full application note below. 

Question:  Can we measure ASO (acid-soluble oils) in alkylation besides H₂SO₄ (sulfuric acid)?  

Answer:  Refractometers are highly effective in alkylation processes for measuring acids like H₂SO₄. They can monitor acid concentration before and after the reactor and are not affected by acid-soluble oils (ASO). This ensures accurate measurements and efficient process control.

Question: For measurements in aggressive media such as H₂SO₄, is there any degradation of the instrument or decrease in measurement accuracy with exposure time? If yes, what are the recommended maintenance procedures?  

Answer: Degradation concerns are valid when dealing with aggressive media like sulfuric acid. Although the prism itself is resistant to H₂SO₄, using 316SS in concentrations above 90% is recommended. For more aggressive applications, exotic metals like Hastelloy or Alloy 20 should be considered. Regular maintenance and careful material selection are essential for ensuring the longevity and accuracy of the instrument.

Question: For H₂SO₄ concentrations ranging from 0-80% and 85-100%, do we need to use two refractometers? What about the range between 80% and 85%?  

Answer: It is advisable to use two refractometers for sulfuric acid concentrations from 0-80% and 85-100% due to the non-linear refractive index curve, which becomes negative between 80% and 100%. This approach enhances accuracy by addressing the unique measurement challenges in these concentration ranges.

Contact Vaisala to go beyond these expert insights and enhance your understanding of refractive index sulfuric acid applications in the chemical industry.