Analysis of the Process of Mineral Sequestration of CO2 with the Use of Fluidised Bed Combustion (FBC) Fly Ashes

There is a current focus on replacing the generally accepted conventional power generation technologies with more advanced ones that will better protect the natural environment. The need to limit CO2 emissions from power generation plants presents a problem that must be solved in many countries that use coal or lignite as basic fuels. One potential option is mineral sequestration performed using side products of fossil fuel combustion, such as fluidised bed combustion (FBC) fly ashes. Fluidised bed combustion (FBC) lignite fly ashes are characterised by a high storage capacity of 15.7%. Research conducted with the most commonly used method of direct mineral sequestration—CO2 trapping with fluidised bed combustion (FBC) ash in water suspension—has indicated a very high level of carbonation of CO2, reaching 11%. Calcite was the basic product of carbonation. The calcite content increased from 2 to 12% in the suspension subjected to treatment with CO2. Furthermore, CO2 reduced the pH and limited the leaching of impurities, such as Zn, Cu, Pb, Ni, As, Hg, Cd, Cr, Cl, and SO4. The fly ash suspensions subjected to CO2 treatment can be used in industry in the final stage of carbon capture and utilisation (CCU) technology, which will further contribute to the implementation of the circular economy.

Utilization of Mineral Sequestration for CO2 Capturing in Car Parks and Tunnels

Decreasing the emissions of CO2 that come from vehicle exhaust, especially in car parking and tunnels, is so vital. CO2 emissions cause corrosion to a reinforcement of concrete. Thus, there is a need to provide a layer that protects the reinforcement from the reach of this harmful gas. This work goals to investigate the efficiency of using board units from Pozzolime concrete and pervious concrete to sequestrate CO2 from the environment and then to convert it into calcium carbonate inside the concrete. The units have dimensions of (200×400×40±5). All specimens were cured in a water tank after about 48 hours after casting. Then paint the sample from all surfaces (three layers) excluding the top surface. The pervious concrete and Pozzolime specimens, at age of 28 days, were put in the chamber, then the gas was supplied to the chamber with concentrations of 15%, 25%, and 50 %, for 24 hours. The efficiency was evaluated through carbonation depth, CO2-uptake, and weight change. The results showed that the maximum CO2 uptake was recorded at the age of 28 days for Pozzolime concrete when exposed to 50% of CO2 concentration.