Green liquor dregs for carbon capture, utilization, and storage: initial LCA and economic analysis

Abstract Green liquor dregs (GLD) are one of the major inorganic residues generated during the production of pulp through the kraft process. Currently, GLD mostly end up in landfills. Research is underway to explore diverse alternative applications for GLD, and this study conducts an initial assessment to evaluate the feasibility of utilizing GLD as a material for carbon capture, utilization, and storage. The study aims to provide support for further experimental work in this area. Despite uncertainties, the carbonation of GLD demonstrates the potential for carbon capture, utilization, and storage. The results show that the environmental impact of the GLD carbonation process is predominantly influenced by the intended use of the final product (carbonates). Environmental benefits are estimated to range between 142 and 686 kg CO 2 e/tonne of GLD, depending on the adopted scenario. The most environmentally advantageous option involves replacing materials with a high carbon footprint. However, options like using carbonates as construction materials, which necessitate energy-intensive drying, may only be economically viable with access to a low-cost energy source for drying.