PULP & PAPER
The Pulp & Paper industry can utilize Pixact measurement technology in several production phases and process operations. The Pixact online measurement systems for solid particles (including fibers, fines, impurities and precipitates) and gas content estimate enable the replacement of laboratory analyses with online quality monitoring and process control to optimize, e.g., energy consumption and chemical dosage. Pixact applications range from the early stages of pulp production to the water treatment facilities in the paper mill. In the following, three Pixact products and their applications in the pulp and paper industry are presented.
Pixact Stock Monitoring
The Pixact Stock Monitoring (PSM) is designed for the analysis of impurities and color of flowing pulp suspension. The PSM system is installed directly on the process line. The system provides real-time measurement data without the need for preparing samples for analysis.
The system can be used with brown, bleached or recycled stock. Recognizable impurities include, e.g., shives and other uncooked components, bark, soot, silica particles, rubber, resins, stickies, ink and precipitated chemicals. The statistics provided by the system include:
Number of dirt particles (e.g. pcs/m2 or pcs/kg)
Size (d [mm] or A [mm2]), shape and color of each particle
Particle classification and statistics for each class separately
In addition to numerical results, images of detected impurities are stored for later inspection. The data can be used to adjust process parameters to solve quality and runnability issues and, as a result, lower operating costs and avoid costly interruptions in production.
In a pulp mill, the PSM system can be installed in several location from washing to bleaching. Potential installation locations in a paper mill include stock preparation, broke system and short circulation. To identify the origin of impurities and enable efficient corrective measures, a PSM system can be installed in two or more locations in the same process.
Pixact Particle Monitoring
Pixact Particle Monitoring (PPM) technology can be used for the analysis of fiber characteristic in pulp and paper applications. Optimized analysis algorithms are developed for both traditional fiber and microfibrillated fibers. In online applications the PPM system is equipped with an automatic dilution station. The system produces real-time data on fiber size and morphology, such as:
Fiber length and width
Fiber morphology (kinks and curls)
In addition to numerical results, images of fibers are stored for later inspection.
With the help of the data, for example the refining process can be controlled efficiently, which may result in notable reductions in energy consumption.
White water analysis & water treatment
The Pixact Particle Monitoring technology can be applied various filtrates and water treatment processes in pulp and paper production to produce in-depth measurement data on particle populations far beyond the capabilities of the traditional turbidity measurement.
For example, in white-water analysis, the measurement system is equipped with a dilution unit and installed on the paper machine white-water circulation to analyse particle populations. The PPM classifies detected particles into categories, such as:
The system then calculates statistics, such as mean size and concentration, for each category. The results can be used to determine the process state, predict and improve machine runnability as well as adjust chemical dosages.
Pixact Bubble Monitoring
Pixact Bubble Monitoring technology is designed for the online analysis of bubble suspensions. The measurement system is applicable to any type of gas dispersion: It can be used from the detection of individual gas bubbles in liquid to the analysis of high gas content foams.
Application in the Pulp & Paper industry include: detection or air in stock preparation, analysis of oxygen dispersion in delignification, analysis of the performance of flotation, analysis of foam quality in foam-laid forming and molded pulp.
The results provided by the system include:
Bubble size distribution (arithmetic, Sauter and volumetric) and related statistics (mean and std, 10%/50%/90% percentiles)
Estimate of bubble concentration / foam density
Index for foam / bubble suspension homogeneity
With the help of the PBM technology the processes and product quality can be controlled efficiently by adjusting mixing speed, gas and chemical dosage, minimizing residual gas etc.