Study of the post-combustion CO2 capture applied to conventional and partial oxy-fuel cement plants

The present work was focused on the application in the cement industry of the post-combustion CO2 capture technology using amine-based chemical absorption. Besides conventional conditions, investigations were performed on a concept called partial oxy-fuel combustion applied to cement kilns leading to more CO2-concentrated flue gas (y(CO2) up to 60%) and allowing to reduce the solvent regeneration energy consumption. The purpose of the study was to highlight and evaluate this reduction. Firstly, the performances of several solvents were evaluated thanks to screening tests at lab (results with a cables-bundle contactor) and micropilot (absorption-regeneration unit) scales considering different CO2 contents (y(CO2, in) = 20-60 vol.%). Simple and blended solvents were tested in such conditions, such as primary and secondary alkanolamines (benchmark Monoethanolamine (MEA), Diethanolamine (DEA) and cyclical di-amine (Piperazine (PZ)). It was shown that the use of activated solutions (such as DEA 30 wt.% + PZ 5 wt.%) presented particularly high absorption performances both in conventional and high CO2 contents conditions. Secondly, Aspen Hysys (TM) simulations were carried out considering cement plant flue gas. For MEA 30 wt.% an increase of y(CO2) from 20% to 44% leads to a 26% decrease of the regeneration energy (from 3.36 to 2.48 GJ/t(CO2)), which is clearly encouraging. As perspectives, new absorption-regeneration tests at micro-pilot scale and simulations will be performed with other solvents in order to have a more global evaluation of the interest of partial oxy-fuel conditions for the cement industry. (C) 2017 The Authors. Published by Elsevier Ltd.