(331e) Techno-Economic Study of Ca-Looping Processes for Carbon Capture From Cement Plants

Cement is a key construction material, and gains on demand of cement are expected with a trend around six percent in 2012, reaching 3.78 billion tons [1]. The cement industry is one of the largest CO₂ emissions source, accounting for 2 Gt CO₂/year in 2007 [2]. The excessive CO₂ emissions of a cement plant are not only related to high energy demand but also the emission due to raw material calcination. A more efficient thermal management can reduce the carbon emissions from cement plants but the extent of capture is very limited since the heat required for its endothermic reaction has to be provided. Therefore, it is essential to deploy carbon capture technology on cement processes in order to achieve the target to reduce its CO₂emissions by up to more than 90%.

We have investigated process integration of a Ca-looping process with cement plants aiming to select optimal feed stream, determine operating conditions of the circulating fluidised bed process, and estimate CAPEX and OPEX. A model for a carbonator, where hydrodynamics in fast fluidisation, reaction kinetics as well as active fraction of the sorbent are taken into account, has been implemented in Matlab and incorporated into a cement process flowsheet using Honeywell’s Unisim process simulator. The entire process simulation also includes a steam cycle supplementary to the Ca-looping process for heat recovery and an air separation unit for 95% oxygen supply to the calciner. It enables us to evaluate the incremental cost for carbon capture precisely. Different post-capture processes such as amine and membrane have also been investigated for the carbon capture for a cement plant, and the comparison of these processes with Ca-looping process can be conducted.      

We would like to acknowledge the financial support from the Turkish Ministry of Education and the Engineering and Physical Sciences Research Council under grant EP/F034520/1 (Science & Innovation Award).

[1] CW Group Global Cement Volume Forecast Report, 2012.

[2] IEA, Energy Technology Perspectives 2010; International Energy Agency: Paris, 2010.

[3] European Cement Research Academy GmbH, Carbon Capture Technology - Options and Potentials for the Cement Industry, Technical Report, TR 044/2007, July 2007.