Pulp Paper & Logistics


VALMET 13


Valmet MAP Q parameters can be accessed remotely and locally to provide immediate support as required


consistency, completed the delivery to the Pietarsaari paper mill.


Early evidence of fibre spins “For certain grades, fibre spins (where fibres mechanically entangle themselves very tightly) can be a particular problem, as they project from the surface of the paper and cause holes in a barrier coating or lamination applied later,” says production development engineer Jyrki Härkönen. “Valmet MAP Q has shown that some of the fibre spins are present in the incoming pulp, and some are created in our stock preparation. Within 50 minutes of pulp coming into the mill to the reel, Valmet MAP Q provides much earlier evidence of fibre spins, and we can adjust process conditions to minimise them. “The analyser has shown us the


effect of refining conditions and issues like plate wear on fibre spins and other pulp properties to enable future follow-up for further improvement.”


Remote support from the Valmet Performance Center Following installation, the first calibrations were made during the start-up at the end of


Eight sampling points had been decided on – first, to monitor incoming bleached and unbleached pulp, and then to follow fibre development after the high consistency (HC) and low consistency (LC) refining stages. Final pulp quality is monitored with a sampler after the machine chest and another in the headbox recirculation. The eight sampling points are automatically measured in sequence, with each measurement taking approximately five minutes


November 2018. After a second on-site visit by Valmet for the SR freeness calibration and the introduction of the chemistry module, the remote connection capability then came into use. “Our laboratory technician took samples from the analyser, and the Valmet engineer was able


The Valmet MAP Q installation in Pietarsaari


to remotely make the necessary calibration adjustments. With the remote connection, Valmet assistance is always close at hand for help with process troubleshooting and equipment support,” says Härkönen. Myllylä adds: “Additional SR freeness calibration has been


undertaken remotely to further increase accuracy, and today we are closely following the SR values, fibre length and fibrillation degree, which will enable us to develop control models to optimise refining and save energy. We are still in the learning phase, but a thesis project in 2020 will take us much further.”


A process engineer’s tool “Today, we operate the analyser as a process engineer’s tool, but ongoing work to integrate the measurements in the process control system will see us take the next step toward automatic refining control,” says Myllylä. “We can have up to 15 grade changes per day and presently adjust conditions according to grade specifications. With the analyser, we now have the capability of enhancing control according to incoming pulp properties, as well as matching grade specifications with the incoming pulp. “We can now produce certain


grades according to incoming pulp properties and optimise refining, which translates to energy savings and reduced broke while producing the same high quality.”


January/February 2021


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