'Refractometry offers huge benefits for different process steps'

There are lots of methods on the market to measure the concentration of a liquid inline or online. Not all methods are equally suitable for every application. For example, a number of them are sensitive to temperature, pressure fluctuations or pumping liquids around. Refractometry does not have these drawbacks, which means it can offer huge advantages for various process steps. Kevin Boels and Feb Theys of Elscolab elaborate on this measurement method.

"Refractometry is an optical measurement technique that measures the refractive index of light in a liquid," begins Kevin Boels, sales engineer at Elscolab. "With an LED we shine in the direction of the medium which will cause the light to bend. The refraction angle depends on the concentration of dissolved substance. This makes it possible to determine the concentration of dissolved substance precisely and in real time. One of the best known applications is Brix, the standard unit in which sugar concentration in liquids is expressed. Refractometry is therefore already well established in the food sector, but also in other sectors such as chemistry, pharma, oil and gas, this measurement technique offers many advantages over other measurements."

Advantages

Feb Theys, also a sales engineer at Elscolab, adds: "Many techniques to reduce concentrations
to measure have limitations. For example, in industrial processes, the flow rates are not always consistently the same so measurement techniques such as coriolis flow meters and U-tubes do not always show the correct density determination. This is because they are sensitive to flow fluctuations and turbulence. Refractometers are insensitive to this." Temperature fluctuations, change in pressure and resonance can also affect measurement results. Boels: "With refractometers, temperature changes are immediately compensated for, while the VAISALA/K-Patents inline refractometers we work with capture pressure variations and vibrations by means of special CORE (Compact Optical Rigid Element) optics." Air bubbles or solid particles are not a problem either. "Only a dissolved substance determines the refractive index so both a small and large amount of air bubbles or solid particles play no role for the refractometer. The measurement remains reliable."

Payback period

"Refractometers quickly pay for themselves," Theys states. "They can be installed inline in, for example, a process pipeline. Measurements are therefore made on site in the process itself, eliminating the need for sampling, dilution or filtration, while results are immediately available in real time. Moreover, refractometers are virtually maintenance-free and are resistant to SIP and CIP cleaning so you don't have to worry about them after installation. This can save a company a lot of time and money. Also consider, for example, monitoring during the CIP cycle that allows you to avoid wasting acid, lye and water."

Applications

Refractometry is very suitable in various sectors. In the food sector, the measurement technique is best known, for example to measure sugar concentration in orange and other fruit juices, but also in the preparation of confectionery, tomato-based products, jellies and other products with combinations of fruit, flavorings, pectin, acid, sugar or starch sweeteners. In the oil and gas sector, the refractometer is suitable for upstream, midstream and downstream activities. Examples include determining the aromatic content of hydrocarbon streams, determining the amount of sulfuric acid in the recovery of used acid, glycol dehydration, H2S removal, and so on. In chemistry, the determination of concentrations to certain chemical solutions is often required to optimize processes, making the refractometer a highly suitable instrument.

Boels: "In pharmacy, medical and biotechnology, refractometry is also a valuable analysis technique, not only in continuous processes to permanently monitor quality. Also in batch processes, the analyzer provides important information about reactions and process steps. Some applications include evaporation, fermentation, filtration, mixing, diluting and blending of solutions, coagulation, quality control, etc. In short, the refractometer can be widely used in various sectors and for various applications." Theys concludes, "Elscolab is working with a partner with years of experience in refractometry which guarantees quality and reliability."

Visit Elscolab at the WoTS - Booth number 7C004