Monitoring the Pulping Process Online – The Benefits

The pulp and paper industry is full of difficult processes and aggressive matrices. Continuous monitoring of quality and analyzes must be carried out to run every phase of the papermaking process optimally. Evaluating vital process parameters atline, inline or online instead of manual offline laboratory study not only saves time but also optimizes process efficiency while lowering operation cost. As a combined part of process control and automation, real time analysis can help one enhance yields and increase production quality.

Metrohm Process Analytics provides different analytical approaches in many different analyzer configurations for any requirement such as NIR spectroscopy, ion chromatography, photometry, titration and ion-selective measurements. Metrohm’s online process analyzers and customized sample preconditioning systems are produced in the Netherlands and maintained by Metrohm’s local service engineers globally.

Kraft Process

Kraft process is the main pulping process with maximum chemical recovery efficiency. Sodium hydroxide and sodium sulfide, the key chemicals used to pulp wood (otherwise known as liquors), are tracked in different phases of the cooking operation from the digester to the recovery boiler to the causticizing plant. Constant, dependable online measurements result in a more effective process, superior quality of the white liquors for reuse in pulp production and energy savings through efficient generation of high pressure steam.

Sample Preconditioning

Online sample preconditioning systems reduce maintenance costs and help analyzes run more smoothly.

Metrohm Applikon can offer a comprehensive and perfect solution for almost any application due to it expertise in process analytics for more than 40 years. Projects vary from a single analyzer in association with easy sample preparation to full turnkey packages with piping, wiring, shelters and interfacing.

Settlers installed on-site for some of our process analyzers in pulp and paper mills.

Settlers installed on-site for some of our process analyzers in pulp and paper mills.


Online or Atline Analysis of Pulping Liquors

The Process Analyzer ADI 2045TI can be used to test Green, Black, White & Wash liquor with multiple sample lines yielding results for closed loop control. For atline analyzes, the ProcessLab ADI 2045PL is typically used for many sampling points and parameters that do not need frequent analysis or quick response times.

  • Conformity to SCAN-N 30:85 – Effective, Active and Total Alkali in pulping liquors
  • Carbonate
  • Hydroxide
  • Sulfide
  • CE % (causticizing degree)
  • and many more

ProcessLab ADI 2045PL

ProcessLab ADI 2045PL

Sulfate Measurement by Thermometric Titration

Sulfate concentration can be simply measured with thermometric titration. At present, Metrohm is the only manufacturer in the market providing online thermometric titration, and the 2035 Thermometric Process Analyzer is perfect for this application.

Combined with the ABC titration results from the Process Analyzer ADI 2045TI, this gives a perfect indication for the degree of reduction and information about the recovery boiler efficiency as a reactor.

  • Enthalpy change of the reaction is monitored
  • Robust probe is resistant to aggressive samples
  • No sensor calibration or maintenance required
  • Fast and accurate results: Thermoprobe response time of 0.3 seconds with a resolution of 10–5 K

Process Analyzer 2035 Thermometric

Process Analyzer 2035 Thermometric

Spectroscopic Applications for Papermaking

Near infrared spectroscopy can be used for quick, reagent-free, non-destructive analyzes. Metrohm Applikon provides two NIRS lines such as XDS and PRO. It is possible to configure these two for both contact and noncontact measurements, with an extensive portfolio of fiber optics and probes to tackle any job.

  • Kappa number
  • Lignin content
  • Kraft pulp yield
  • Tall oil
  • Coatings
  • Component analysis (clay, TiO2, fillers, ash, etc.)
  • Moisture
  • Resin
  • Brightness
  • Wood species
  • Hardwood/Softwood ratio

NIRS XDS Process Analyzer

NIRS XDS Process Analyzer

NIRS Analyzer PRO

NIRS Analyzer PRO

Other Important Parameters

Metrohm Process Analytics provides much more than what can be outlined here. The company also provides complete process solutions for different areas, like analysis of Calcium and Magnesium in brine in the production of Cl2 used for bleaching purposes. The Process Ion Chromatograph can be used for measuring either sulfur species or organic acids in process water or even trace impurities in steam so as to shield the turbines from excessive scaling, for instance.

Irrespective of application, the turn-key process solutions from Metrohm Process Analytics are necessary when it comes to maximizing throughput and saving money in a plant.

This information has been sourced, reviewed and adapted from materials provided by Metrohm AG.

For more information on this source, please visit Metrohm AG.


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