Techno-economic and environmental assessment of CO2 capture technologies in the cement industry

Cement production is one of the most carbon-intensive industrial sectors, with immediate need of decarbonization. In this work, the feasibility of integrating three alternative CO2 capture units in a cement industry in Greece is evaluated from the techno-economic and environmental standpoint. Two Carbonate Looping scenarios, using CaO- and MgO- based solids as high- and intermediate temperature CO2 capture materials respectively, are compared to the commercial amine scrubbing process which uses an aqueous solution of mono-ethanolamine. The study comprises thorough design of the process flow diagrams, calculation of the mass and energy balances and sizing of the necessary equipment. Using these as basis, the fixed investment and the auxiliaries' cost are calculated, and a complete economic analysis is conducted for all three configurations. The commercial solvent absorption technology results in a total CO2 capture cost of similar to 56 $/tonne, followed closely by carbonate looping with limestone-derived material (60 $/tonne), despite the heavy capital investment for the latter. The life cycle analysis results further support the application of carbonate looping with limestone, which demonstrates 22% lower total environmental impact compared to amine absorption. On the other hand, carbonate looping with magnesite has little benefit for the environment (only 0.64% lower footprint than amine scrubbing), and higher overall cost for CO2 capture (similar to 80 $/tonne of CO2). Although the implementation of such technologies would lead to increased cement production cost, the strict environmental policies and taxes for CO2 emissions could render these options more attractive in the near future.