Municipal solid waste incinerator (MSWI) fly ash was used for accelerated carbonation via bubbling of gaseous carbon dioxide (CO2) after treatment with sodium hydroxide (NaOH). The influence of alkaline concentration and volumetric flowrate of CO2 was investigated. Experimental results showed that carbonation reduced the leaching of Cu, Pb, Zn, and Cr. The pH of leachate decreased from around 12 to 10.5. The content of soluble chlorides was also decreased after carbonation. Additionally, the application of accelerated carbonation enhanced the sequestration of CO2 from MSW incineration plants. The TG/DSC analysis indicated that MSWI fly ash sequestrated approximately 185 g CO2/kg waste.

Mineral carbonation is one of the safest permanent carbon dioxide sequestration methods. Carbon Capture & Utilization (CCU) is a process that utilizes available resources by removing carbon dioxide in a method of mineral carbonation. It can be applied to industries producing high carbon dioxide emissions. This study aims to investigate the absorption performance of carbon dioxide at high concentrations. Calcium hydroxide suspension was used as an absorbent. In addition, NaOH and Mg(OH)2 were used as additives. Carbon dioxide removal efficiency with NaOH increased from 30% to 90% when the additive amount was increased from 1wt% to 3wt%. In the case of Mg(OH)2, carbon dioxide absorption efficiency was minimal regardless of the additive amount. In addition, the solid byproducts werec onfirmed by X-ray diffraction spectra and SEM images.

Waste gasification can generate hydrocarbon gases that may be utilized for the synthesis of chemicals or liquid fuels, or for fuel cell power generation, if extensive, deep syngas cleaning is initially conducted. Conventional gas cleaning technology for such applications is expensive and may limit the feasibility of wet technology. Conventional cold gas cleanup (scrubbing by solvents) technique needs the temperature of raw waste gasification gas ranging from 900 to 1600℃ reduced to room temperature. Then, the cleaned - up syngas needs to be reheated. Obviously, the process is energetically inefficient. It is the objective of this study to economically meet the most stringent cleanup requirements without reheating syngas for these applications. We investigated the temperature and pressure effect in breakthrough performance of various sorbents for desulfurization and de-chlorination. Based on the results obtained during the desulfurization (Fe₂O₃, Fe₃O₄, ZnO) and the dechlorination (Na₂CO₃, NaHCO₃, Na₂O) screening tests, ZnO and Na₂O were selected as preferred optimum sorbents. H₂S breakthrough time corresponds to an effective capacity of approximately 11 g Cl/100 g of material. Also, HCl, breakthrough time corresponds to an effective capacity of approximately 5 g Cl/100 g of material. ZnO and Na₂O at high temperature of around 550℃ display high sorption performance and removal efficiency for waste syngas along with H₂S and HCl. Although there is an issue of CO₂ recovery in warm gas clean-up technology for desulfurization, we have obtained an interesting new alternative warm gas clean-up system with heat budget merit.