掺烧污泥型粉煤灰矿化封存二氧化碳

Mineralization and storage of carbon dioxide by the fly ash from co-firing of municipal sludge and coal

为了探索燃煤电厂掺烧市政污泥并利用该粉煤灰矿化封存CO_(2)的处理模式,研究掺烧污泥型粉煤灰矿化封存CO_(2)的能力和影响因素,并对该粉煤灰和矿化灰渣进行表征分析,同时研究其矿化反应机理。结果表明,掺烧污泥型粉煤灰中含有大量的反应活性较强的Ca、Mg元素,矿化封存CO_(2)能力强,最优反应条件为碳酸钠溶液质量浓度3%、CO_(2)流量200 mL·min^(-1)、粉煤灰投加量50 g·L^(-1)、温度100℃和反应时间80 min,此时单位粉煤灰矿化封存CO_(2)量可达到最大值125.05 mg·g^(-1)。反应产物矿化灰渣的微观形貌发生了较大改变,掺烧污泥型粉煤灰中钙离子大量溶出并经过碳酸化反应生成了碳酸盐沉淀。该处理模式有望大规模推动市政污泥的无害化、减量化和资源化并就近实现燃煤电厂碳减排,进一步拓宽粉煤灰大规模综合利用领域。

In order to explore the treatment method of co-firing municipal sludge and coal in power plants and utilizing the fly ash to mineralize CO_(2),the ability and influencing factors were studied.The characterization of the fly ash and the mineralized ash were conducted,and their mineralization mechanism was studied.The results showed that the co-fired fly ash contained a large amount of Ca and Mg with high reactivity,and had a strong ability to mineralize CO_(2).The optimal reaction conditions were 3%mass concentration of sodium carbonate solution,CO_(2)flow rate of 200 mL·min^(-1),fly ash dosage of 50 g·L^(-1),temperature of 100℃,and reaction time of80 min.Under such conditions,the maximum amount of CO_(2)mineralized and stored per unit of fly ash can reach 125.05 mg·g^(-1).The microstructure of mineralized ash had undergone significant changes,with a large amount of calcium ions in the co-fired fly ash dissolving out and carbonate precipitation formed through carbonation.This waste treatment model was expected to promote the hazard neutralization,volume reduction,and waste utilization of municipal sludge on a large scale,and achieve reduction in carbon emissions in coalfired power plants nearby,further expanding the field of large-scale comprehensive utilization of fly ash.