Utilization of CO2 from exhaust gas from cement industry aimed to stabilize fly ash from combustion of household waste
About 300.000 t fly ash (dangerous waste) from combustion of household waste is received and processed by NOAH every year.
NOAH has since 2012 studied the possibility to develop an industrial process based on the use of CO2 from exhaust gas from cement industry to stabilize fly ash from combustion of household waste. The neutralization process is based upon the following chemical reaction (carbonation process):
CaO + CO2 → CaCO3
The neutralization process will effectively stabilize the pollutants (heavy metals) by reducing the pH of the final product down to optimal value.
The main purpose of the project was to verify that the mentioned process can be industrialized in a large scale facility. The main results can be summarized as follows:
- The tests confirm that the process effectively stabilize the fly ash pollutants down to acceptable levels. - About 75 kg CO2 is captured per ton of dry fly ash. Consequently, an assumption of 500.000 tons fly ash yearly will by this process capture and convert approximately 40.000 t CO2. - The process can be utilized in areas with large scale industrial CO2 point sources. - Further testing is necessary in order to increase CO2 capture rate, reduce energy consumption and plant uptime.