Decarbonizing the lime-based construction materials industry: A practical guide for cradle-to-gate life-cycle inventory

Abstract

This paper presents an integral parametrized framework to calculate the life-cycle inventory (LCI) in lime-based construction materials manufacturing, utilized for implementing decarbonization strategies in the LCI. The calcination operation is identified as the main source of CO2 emissions, with 0.79 tCO2/t CaO being inevitable (65 % of total emissions). Kiln fuel combustion contributes up to 35 % to emissions. Decarbonization strategies are ranked as: carbon capture, carbon direct avoidance, and circular economy. Parallel Flow Regenerative Kilns result in 40 % lower energy consumption compared to Long Rotary Kilns. Substituting lignite with natural gas can reduce emissions by up to 17 %. Direct CO2 separation from calcite decomposition, coupled with thermal energy recovery, can capture 65 % of the CO2 emitted, reducing kiln energy consumption by 15 % and CO2 emissions from fuel combustion by 13 %. The high purity of captured CO2 offers potential for future use as a valuable by-product. Supplementary raw materials in lime-based binder production have limited effects on CO2 emissions due to unavoidable emissions from calcite decomposition. The proposed process-oriented parametric methodology empowers Life Cycle Assessment practitioners, reducing reliance on generic databases for rigorous and transparent inventory calculations.