Chemical processing

Measuring liquid concentration to control and optimize chemical industry operations

Measuring liquid concentration or density in-line is important in the chemical industry as density variations have impact on both raw materials and finished products. Process safety is also mandatory, since hazardous chemicals represent a potential risk to people and the environment. While managing these challenges, chemical manufacturers strive to produce high-quality products that meet customers’ specifications. To achieve these goals, accurate process measurements, high process efficiency, low energy consumption, and state-of-the-art process control management are crucial. 

In-line measurement of liquid concentration and density directly in chemical process

Vaisala K-PATENTS® process refractometer is designed to measure and indicate inline liquid concentration of almost any chemical or compound.

The refractometer can be installed cost-efficiently in the main processing line, bypass line or vessel to control the raw and in-process materials in order to extract their maximum value and achieve high quality end products. The performance of all types of chemical refining, manufacturing, and quality-control operations can be dramatically improved with Vaisala’s refractive index measurement technology – whether they are in continuous or batch processes. 

Unlike intermittent sampling, continuous monitoring provides instant feedback on changes in the process, and this data can enable real-time and precise process control of the common chemical industry operations, e.g.:

  • Reactor, reaction degree, and endpoint determination
  • Evaporation
  • Dissolving tank or vessel
  • Dilution, mixing or blending
  • Solid-liquid extraction
  • Absorbers and wet scrubbers
  • Ion exchangers
  • Distillation
  • Interface detection and product identification of product-to-product interfaces in loading/ unloading
  • Quality control

Using the Vaisala concentration measurement technique and its easy integration into plant engineering systems enables significant improvements in the plant capacity, the process safety or product yields.

Installed refractometer

Refractive index technique designed for harsh chemical environments and applications

Vaisala K-PATENTS® process refractometer offers accuracy, repeatability and reliability even in the most extreme environments that can be corrosive or abrasive, subject to chemically aggressive solutions, extreme temperatures, pressures, vibration or contamination, humidity and dust, or any combinations of these factors.

  • Designed to Pressure Equipment Directive PED 97/23/EC and ASME Section VIII Division 1 - Pressure Vessels
  • Selection of different IP codes (IEC 60529) and NEMA ratings for the that withstand various harsh conditions and outside use.
  • Special wetted parts materials ranging from Stainless steel and higher alloys to PFCF or PTFE (Teflon®) for harsh environments and chemically aggressive process fluids.
  • Intrinsically safe and hazardous area certification for hazardous areas
MI with user

Vaisala capabilities and services for the chemical industry applications

Vaisala is specialized in in-line process refractometers and optical process analyzers for refractive index-based concentration measurements. Vaisala instruments range from compact probe models for small pipeline and bypass lines to rugged heavy-duty long probe versions for large pipeline, vessel and reactor installations. When standard models are not sufficient to fulfill requirements, please consult the factory for engineered solutions, e.g. special wetted materials or custom mounting accessories and process connections.

Vaisala also provides full range of start-up, commissioning and technical support services to our customers. Our industry expertise includes supply of extensive vendor documentation that is tailored and applied to each contract and client specific data. Local authorized distributors have extensive applications knowledge and they can help specifying the correct instrument for each application requirements.

Related products

Applications in the chemical industry

The performance of all types of refining, manufacturing and quality control operations can be dramatically improved with our liquid concentration and density measurement technology.
Download our application notes for more information.

Applications in the fiber and textile industries

Read our application notes to streamline your fiber processes, optimize use of materials  and resources and reduce impact of harmful chemicals to the environment and humans. 
Download our application notes for more information.

Regenerated Cellulose Fibers

  • The Lyocell Process (If you would like to receive the complete application note, please contact Vaisala).
  • Cellulose Acetate Fiber Production

Synthetic Fibers

  • Polyamide (Nylon) Fiber Production 
  • Polyurethane Elastic (Spandex) Fiber Production Process
  • Fiberglass Production Process
  • Production of Polyacrylonitrile (PAN) Precursor Fibers for Carbon Fibers

Textile Wet Processing

  • Textile Sizing Process
  • Textile Sizing Agents Recovery by Ultrafiltration
  • Polyethylene Fiber Antistatic Agent
  • Textiles Softening Bath

Free e-Book

Download the free eBook on Optimizing chemical and textile fibers processing

Applications in biofuels

Read our application notes to streamline your biofuel processes and optimize use of materials and resources. 
Download our application notes for more information.

Bioethanol Process

  • Bioethanol production dry-mill mash preparation
  • Bioethanol cooking and fermentation
  • Bioethanol purification
  • Bioethanol stillage processing

Biodiesel Process

  • Biodiesel Glycerol Refining

Applications in other industries & operations

Read our application notes to streamline your other manufacturing processes or operations. 
Download our application notes for more information.


  • Automotive Grade Urea Solution Process: AdBlue and DEF
  • Automotive Antifreeze and Coolant Fluids Blending


  • Aviation De-icing Fluid Spraying and Recovery

Metalworking and Machining

  • Metalworking and Machining
  • Metal Induction Hardening
  • Can Coating
  • Acid Passivation of Stainless-Steel Parts

Metal Mining and Refining

  • Longwall Mining: Emulsion Station

Elastomer and Polymer Products

  • Rubber Gloves Manufacturing Process
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