Integrating carbon capture in pulp mills towards negative CO2 emissions: a review and case study on technologies and capture potential

Carbon capture is a key technological option for mitigating climate change, particularly in hard-to-abate sectors. As fossil-based CO 2 sources are expected to decline in future energy systems, large biogenic emission sources are gaining increasing importance. Kraft pulp mills represent some of the largest point sources of biogenic CO 2 , offering the potential for large-scale carbon capture without additional biomass input. This study provides a comprehensive review of CO 2 capture technologies applicable to pulp mills, combined with a meta-analysis of literature data and a comparative techno-economic case study based on representative Nordic (integrated) and South American (standalone) pulp mill configurations. Capture options from the major emission sources – recovery boiler, multi-fuel boiler and lime kiln – are evaluated alongside emerging concepts such as black liquor gasification and alternative capture technologies. Capture potential is assessed using a harmonized metric expressed as tonnes of captured CO 2 per air-dry tonne of pulp produced (t CO 2 /ADt), enabling comparison across technologies and process configurations. The results show that the recovery boiler represents the largest single capture source, with a capture potential of 1.5–2.2 t CO 2 /ADt, followed by black liquor gasification (∼1.45 t CO₂/ADt). Capture costs reported in the literature vary widely (8–263 €/t CO 2 ), with most values below 150 €/t CO 2 . The case study highlights that capture costs are highly site-specific, driven primarily by electricity price and mill-level energy integration. Successful implementation will depend on site-specific energy balances, integration strategies, and the availability of viable carbon capture and storage (CCS) or carbon capture and utilization (CCU) value chains.