Extensive GHG emission avoidance through carbon capture technologies Development of carbon capture technologies in the cement industry gaining traction The abatement of CO 2 emissions from industry processes is recognised as a key challenge for achieving carbon neutrality, especially in the construction sector, in line with the objectives of the EU Green Deal to be achieved by 2050. With regard to CO 2 reduction in the clinker production process, existing technologies as well as new breakthrough technologies need to be deployed. It is now widely acknowledged that the abatement of process-related CO 2 emissions will require the capturing and sequestration or utilisation of CO 2 from cement plants. ECRA has been investigating opportunities for carbon capture in the cement industry since 2007. Its research now serves as a basis for further deployment of this technology.
The target of carbon capture and utilisation/storage (CCUS) is to separate CO
2 from the flue gas to either produce new valuable products or store it long-term in geological formations. Various technologies which are capable of capturing CO 2 from cement flue gases have been developed in the past years. They are grouped into the categories post-combustion, pre-combustion, oxyfuel and other integrated processes. Due to the emissions of process CO 2, pre-combustion technologies are not applied in the cement industry. The focus is rather on post-combustion and oxyfuel technologies.
Oxyfuel technology entails the substitution of combustion air with pure oxygen, which results in a highly CO
2-concentrated flue gas. In a final purification step, the CO 2 is concentrated to a purity level defined by the subsequent processes (transport, storage, utilisation). As an integrated process, oxyfuel technology influences the plant operation as well as material conversion. Intensive research at lab and prototype level (Fig. 1) has raised the maturity level to TRL 6. However, false air intrusion has been identified as the highest technological risk for this kind of process.
The final purification step and the supply of pure oxygen double the electrical power demand of the clinker production, whereas the thermal energy demand remains nearly stable. Based on this, the CO
2 avoidance costs add up to 40-60 €/t CO 2. Cement producers and equipment suppliers (CI4C consortium) are currently working on the reduction of costs by further developing the technology on the basis of planned demonstration.