Mill Efficiency
The consumption of gigajoules per air-dried metric tonne of finished paper or paperboard defines thermal energy intensity across continuous production runs. Converting facilities track this metric to audit steam economy within drying cylinders and chemical recovery boilers. Board manufacturers establish baseline figures during standard operational capacity tests to quantify the energy required to evaporate water from wet cellulose webs.
Steam traps, condensate return lines, and hood exhaust systems influence the overall reading during high speed production.
Drying Load
Evaporation rates dictate the steam demand applied to multi cylinder drying sections during paperboard production. Incoming webs arrive at low dryness fractions, requiring intensive latent heat transfer from pressurized steam headers. Press sections remove mechanical water prior to the thermal phase, reducing the overall drying burden on the machinery.
Thermal energy intensity increases when linerboard basis weights rise or when broke handling requires higher drying capacity. Condensate removal efficiency directly alters steam consumption per tonne of finished substrate.
Fuel Balance
Biomass boilers, bark burners, and natural gas turbines supply the thermal energy consumed during pulp digestion and sheet consolidation. Mills optimize fuel mixes to minimize fossil carbon emissions while maintaining precise steam pressures across turbine bleeds. Non-condensable gases incinerate within recovery furnaces, contributing supplementary heat to the primary steam loop.
Combustion efficiency dictates how much thermal energy reaches the paper machine without excessive stack losses.
