发展适用于燃煤电厂的CO2捕集、利用与封存技术对实现我国碳达峰、碳中和的目标具有重要意义。固体废弃物减量化、资源化和无害化利用是当前我国污染环境防治的战略举措。文章以电厂粉煤灰为研究对象,探究该粉煤灰的CO2矿化特性、降碱及返碱特性、反应前后的理化特性,探讨了反应后粉煤灰的利用途径。研究表明,增大烟气流速能够有效增加CO2矿化和粉煤灰降碱特性,但烟气流速超过一定值后,CO2溶解成为限速步骤,钙的转化率达到饱和;粉煤灰-水体系中引入有机胺可显著提升CO2利用率和粉煤灰的CO2固定量,这是由于有机胺不仅可以提高溶液中CO2溶解度,还能强化粉煤灰颗粒中钙基物相的溶解。CO2矿化不仅可以显著降低粉煤灰碱性,还可降低粉煤灰中某些重金属的浸出量,从而促进粉煤灰的消纳与资源化利用。

Development of CO2 capture, utilization and sequestration technology for coal - fired power plants is of great significance for realizing the carbon peaking and carbon neutrality goals in our country. Solid waste reduction, recycling and harmless utilization is a strategic measure of pollution prevention and control in China at present. Fly ash from Sandaogou Power Plant was selected to investigate the CO2 mineralization and alkali reduction performance through carbonation reactions.The physical and chemical characteristics before and after reaction of the fly ash were also explored, and the potential utilization of the carbonated fly ash were discussed.The results show that increasing the flue gas flow rate can effectively increase the CO2 mineralization and alkali reduction performance of fly ash. However, when the flue gas flow rate exceeds a certain value, CO2 dissolution became fast while the conversion rate of calcium reach saturation. The introduction of organic amines into the fly ash -water system could significantly improve the utilization efficiency of CO2 and the CO2 sequestration capacity of the fly ash. This is because organic amines could not only improve the solubility of CO2 in the solution, but also enhance the dissolution of calcium phase from fly ash particles. CO2 mineralization can not only significantly reduce the alkalinity of fly ash, but also reduce the leaching amount of some heavy metals in fly ash, thereby promoting the absorption and resource utilization of fly ash.