Carbon Footprint of Bleached Softwood Fluff Pulp: Detailed Process Simulation and Environmental Life Cycle Assessment to Understand Carbon Emissions

Wood-based fluff pulp (FP) is the primary raw material for indispensable commodities, including hygienic products. FP substantially contributes to global warming due to the high manufacturing energy demand. Despite FP’s importance, the environmental implications of its manufacture have not been transparently explored. The present study provides the carbon footprint for FP cradle-to-manufacturing gate based on process simulation and environmental life cycle assessment The simulation tracks the anthropogenic and biogenic carbon across the mill’s areas. In addition, the implications of switching energy sources and key operational conditions are evaluated. The results show that 1 kg of FP produces 1.102 kg CO2-equiv. Most of the biogenic carbon fed to the mill (52%) is used to produce steam and electricity. The study shows that switching from natural gas to residual biomass wood pellets represents a reduction of 13.4% of the CO2-equiv emissions. This benefit is increased if wood pellets are used to achieve electrical power self-sufficiency, and even more benefit can be realized if the mill produces 20% surplus electricity to the grid. A critical parameter for global warming potential is the incoming biomass lignin content; the pulping of biomass with higher lignin content produces a black liquor with higher heating value and more solids burned in the recovery boiler, reducing the demand for external energy and thus reducing fossil-based greenhouse gas emissions.