Pixact Crystallization Monitoring


The Pixact Crystallization Monitoring (PCM) technology is designed for the online measurement of industrial crystallization processes. PCM combines in-situ process microscopy with advanced image analysis techniques to produce reliable real-time information on the process.


PCM provides a live camera view of the process and detailed measurement data on crystal characteristics, such as size distribution, morphology and concentration.


Equipped with flexible installation mechanics, PCM can be fitted into a variety of applications from laboratories to manufacturing scale reactors.

Results produced by PCM


Crystallization processes can be broken down into four stages: pre-seeding (feed liquor), seeding, growth and the final state. PCM is used for measuring and controlling crystallization processes from the very beginning until the end of each batch:

  1. PCM detects and analyzes impurities, agglomerates, droplets and bubbles in the feed liquor.
  2. During the seeding phase, the system measures the concentration and size distribution of the seeding crystals.
  3. PCM monitors the size distribution and number of the growing crystals as well as the flowability of the suspension in real time.
  4. Towards the end of the process, PCM provides information on the final crystal size distribution and other statistics.



Measurement results produced by PCM include:

  • Crystal size distribution and related statistics, such as mean and standard deviation, percentiles of cumulative distribution (D10, D50, D90, etc.) and fractions of fine and coarse crystals
  • Crystal growth rate
  • Crystal morphology, such as agglomeration, aspect ratio and other measures of shape
  • Number of crystals and their nucleation rate
  • Suspension flowability



The real-time measurement information produced by PCM is used for the efficient  analysis, control, optimization and troubleshooting of crystallization processes. With the help of the system the yield and capacity of the process can be increased and quality variations in the final product can be minimized.

For the operator, PCM provides tools for

  • Visual examination of the crystal suspension with a live camera view (featuring zoom, pause, etc.),
  • Immediate evaluation of the seeding phase and making decisions on further actions such as reseeding,
  • Online monitoring of crystal characteristics, including fractions of fine and coarse crystals,
  • Detection of secondary nucleation, crystal dissolution and other phenomena, and
  • Batchwise reporting of complete statistics, time trends and distributions.

To increase productivity and promote Best Practice methods, PCM can be used in production development for

  • Benchmarking individual reactors and recipes,
  • Comparing plants with each other,
  • Collecting production databases to help with troubleshooting in case of disturbances,
  • Supporting lab-scale R&D work by providing new insights into crystallization dynamics and related physical phenomena, and
  • Supporting scale-up work by using the same analysis methods from laboratories to production.

PCM measurement hardware and software

The PCM hardware consists of a Pixscope probe and a Pixstation main unit

The measurement probe showcases modular design, which allows the system to be fitted into a wide variety of applications from laboratory to production scale reactors. The probe can be installed on a port on either the side or the top of the reactor. Contact Pixact for more information on installation options.

The Pixstation main unit includes a computational unit and an automation interface. The cabinet is IP67-rated and can be installed in the production space and other demanding environments. The unit can also be customized with optional features, such as a monitor for local operation or a complete selection of automation interfaces. The design supports both fixed and mobile installations.

The PCM software is an all-in-one tool for analyzing and reporting measurement data

The PCM software controls the entire measurement procedure from data acquisition to the reporting of results. It can be used as both a fully automated online measurement software and an effective R&D tool with access to all necessary settings as well as manually controlled data acquisition and analysis.


Key features of the software

User-friendly adjustment of imaging parameters

  • Automatic camera controls
  • Adjustable image refresh frequency
  • Zoom and pause of the live view

Powerful analysis algorithms

  • High-performance image analysis techniques that convert the image stream into real-time quantitative information
  • Customized image analysis features on request

Flexible reporting tools

  • Image data can be stored on an internal or external hard drive
  • Results exported in Microsoft Excel® or CSV format
  • Internal database for the measurement results

In addition to the live view of the process, the Pixact  Crystals software displays numerical values, trends and distribution plots for the parameters measured on the screen.

The Pixact Crystals software automatically generates a detailed measurement report for each batch or time period defined by the customer. In addition to numerical data, the report contains trends for selected results and time-stamped images of the process.

Typical applications


  • Real-time process control based on the measuring of crystal size distribution and nucleation rate
  • Batchwise benchmarking with the help of the data produced by PCM (e.g. trends for crystal size and growth rate)
  • Online quality control based on the comprehensive statistical analysis of crystal size, including mean, standard deviation and the percentiles of cumulative distribution (D10, D50, and D90)
  • Detection of spontaneous crystallization
  • Detection of crystal dissolution
  • Analysis of solution properties, including turbidity and the detection of dirt particles and other agglomerates

Technical specification

System description

Measurement principle

Optical configuration options

Image area [mm]

Image resolution [µm/pix]

Measurement range [µm]

Power supply

Automation input/output


Online measurement system for the real-time analysis of crystallization processes

Direct optical imaging of crystal suspensions accompanied by proprietary image processing and analysis techniques


8.5 x 7.0




4.3 x 3.5




2.1 x 1.8



All system components 24VDC, power supply unit 230VAC/50Hz

Profibus, Modbus, Analog (mA, V), Digital (5-24VDC)

IP67, ATEX on request


Probe diameter

Probe length

Measurement gap


Probe head


Optical windows




Min. 25mm, standard 31mm

Max. 300mm, standard 100mm

1-20mm (fixed, not adjustable)


Stainless steel AISI316L (other materials on request)

Sapphire or borosilicate

NBR, PTFE, FPM, EPDM, silicone

Directly on the process equipment using DN25 or larger fittings. Custom adapters for existing inlets can be delivered. Note that all magnifications are not available for all installation options.

Operating temperature

Max. operating pressure

Probe head: -20C to +120C

Housing: -20C to +85C (cooling options available)

4 bar


(C) Pixact Ltd, 2018

tel.: +358 (0)10 439 2400         email: info@pixact.fi