Techno-economic assessment of CO2 capture from aluminum smelter emissions using PZ activated AMP solutions.

In order to reduce its greenhouse gas emissions without drastically changing currently-used processes, the primary aluminum industry will need to consider capturing CO₂ released in the electrolytic cells. In order to make the capture more economically attractive to the aluminum industry, the possibility of using a blended amine absorption solution which combines the advantages of two different amines (a fast reactivity from a cyclic polyamine, piperazine (PZ), and a high absorption capacity and low regeneration cost from a sterically-hindered alkanolamine) is considered in this work. Specific to an aluminum plant, not only the costs and benefits of a CO₂ capture facility are evaluated, but also the possibility and cost of coupling the capture process with a waste heat recovery strategy. A mixture of 0.08 g/g PZ and 0.32 g/g AMP appears to be the most appropriate, reducing the capital costs by 25 % and operating costs by 29 % compared to the use of MEA (monoethanolamine) solutions. The capture cost is evaluated to be 65.10 $/ton of CO₂ avoided (without carbon tax). A thermal integration of the capture plant within the primary aluminum smelter could further reduce the cost to 57.57 $/ton of CO₂ avoided, or equivalently, 69.56 $/ton of Al produced (without carbon tax). [ABSTRACT FROM AUTHOR]