Unlocking Efficiency in Sulfuric Acid Applications: Expert Insights

Liquid Measurement of H2SO4 (sulfuric acid) with refractometer
Industrial Measurements
Liquid Measurements

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.

Application Note: Sulfuric Acid Alkylation

Learn why it is important to determine the proper amount of acid to processes by combining routine sample titration analysis with continuous monitoring using Vaisala's in-line process refractometer. 

In-line process monitoring provides assurance in between  titration measurements because a Vaisala PolarisTM refractometer will show any gradual changes in the acid flow control. This reduces unit acid consumption and helps prevent "acid runaway" that can occur if acid strength goes below 85-87%. 

Learn more


Kevin Green, Industry Expert & Regional Sales Manager

Kevin has a background in Mechanical Engineering and brings many years of experience in instrumentation, sales and product management with companies such as Emerson – Rosemount Measurement, McCrometer, and ABB. At Vaisala he is primarily focused on measurement applications applied to industries such as semiconductors, food and beverage production, chemical processing, and pulp and paper manufacturing. In his spare time Kevin enjoys cycling and mountain biking, skiing, tennis, and spending time with family and friends.

Dave Lobach  -  Rocky Mountain Instrumentation

Dave Lobach, Rocky Mountain Instrumentation Inc.

For over 30 years, Dave Lobach has been committed to helping clients with their manufacturing and processing applications. In his time with Rocky Mountain Instrumentation, Inc. (RMI) Dave has worked to provide cutting-edge systems for process control. Established in 1991, RMI has been at the forefront of delivering industrial instrumentation across the Intermountain West in the USA, encompassing states such as Utah, Colorado, Nevada, Idaho, Wyoming, and Montana. RMI serves client companies in various sectors, including Oil & Gas, Life Science, Metal & Mining, and Water & Wastewater. With in-depth application experience spanning over three decades, Dave has collaborated closely with industry partners to engineer solutions that meet the demands of modern industrial applications.

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