Revamping of the long fiber line at PM6 Essity Valls

Identifier:  TFM:2243

Handle: https://hdl.handle.net/20.500.11797/TFM2243

Authors:  Marquès Bové, Pau

Abstract:
This project focused on improving the long fiber (LF) line of Paper Machine 6 (PM6) at Essity Valls to reduce product variability and energy consumption, especially during kitchen towel production. The main issue identified was the oscillatory behaviour of Specific Energy Consumption (SEC), caused by the discontinuous discharges of the LF pulper into the dump chest. These oscillations were transmitted through the stock preparation process and affected machine direction (MD) tensile strength of the paper sheet and drying capacity of the machine. To address this, a dynamic model was developed to simulate SEC behaviour across the stock preparation process. After evaluating several alternatives, the selected solution involved installing a new conical refiner after the LF mixing chest and constructing a pipeline to transfer short fiber pulp from the SF mixing chest to the LF machine chest. These modifications significantly reduced SEC oscillations from 144 to 83.2 kWh/t in the LF dump chest and from 16.5 to 4.03 kWh/t in the paper machine headbox. The project showed strong economic viability caused by the promising expected savings due to the reduction of electrical energy consumption in the refining stage and the improve of the MD tensile strength variability.