Benchmarking Laboratory Fiber Yield Assessment Methods for EcoModulation Fee Calculation
Laboratory fiber yield metrics depend on screen slot geometry and ash corrections, directly determining EPR eco-modulation fee surcharges on packaging.
Pulping Consistency
Fibre Concentration
Solids content in the stock determines the mechanical behaviour of the pulp during processing. Within the mill, pulping consistency influences the efficiency of pumping, screening, cleaning, and refining operations. It is typically categorised under four levels ranging from low to high consistency to define the flow characteristics.
This variable dictates the amount of energy required to agitate the slurry and the type of equipment needed for transport.
Friction Management
Friction between fibres increases as the water content is reduced, which alters how the stock reacts to mechanical shear. Maintaining a stable pulping consistency is necessary for uniform refining, as the distance between the refiner plates must be adjusted based on the thickness of the fibre mat. High-consistency systems use less water and chemicals but require specialised pumps and screw presses to move the thick material.
Low-consistency systems allow for easier removal of contaminants through centrifugal cleaning and fine screens. Automated sensors in the pipeline provide real-time data to adjust the flow of dilution water.
Final Properties
Final sheet properties depend on the steady management of the fibre-to-water ratio. If pulping consistency fluctuates, the basis weight and strength of the paper will vary across the production run. Precise control at the headbox ensures that the formation of the web remains uniform.