Effective carbon emission reductions from using upgraded fly ash in the cement industry

A system dynamics model is presented by simulating five different cement life-cycle scenarios in order to quantify the net CO2 reductions when using upgrading processes of fly ash. Ultra-fine grinding for the mechanical activation of FA is the UP modelled using published and direct data from the equipment manufacturer. A material flow analysis (MFA) was carried out to describe the scenarios and to simplify the life-cycle approach. It was found that the upgrading process modelled can have maximum value of 3.98 GJ/tonne of fly ash and still be able to produce net reductions. The same model also estimated that an 80% of the total reductions are avoided when ultra-fine grinding consumes 0.75 GJ/tonneFA of energy, compared to emissions from the baseline cement. The model is also complemented by reviewing the current use of FA as a SCM in the cement industry and by presenting a holistic systems thinking analysis. The model can also be further expanded to simulate other life-cycle scenarios which can include multiple upgrading processes and other materials.