利用凹凸棒改性石灰石增强CO_2循环捕集效率

Enhancement of CO_2 Sequestration of Limestone by Modified with Attapulgite

石灰石作为天然的CO2吸收剂,可有效的捕集烟气中的CO2,但随着循环反应次数的增加,石灰石颗粒表面会发生严重的烧结,使其酸化率迅速发生衰减。本文中利用自然界储量丰富的凹凸棒石对石灰石颗粒进行改性来减缓这一现象的发生,从而提高其CO2的循环捕集效率。凹凸棒石具有的天然纳米纤维状结构可有效的减少石灰石颗粒之间的相互接触,延缓石灰石的烧结团聚现象,从而提高其碳酸化率。实验结果表明:凹凸棒石原矿和提纯后的凹凸棒石均可作为添加剂提高石灰石对CO2的捕集效率,其中经过提纯处理后的凹凸棒石的改性效果最好;通过比较凹凸棒石改性前后的钙基吸收剂经过多次CO2捕集循环后的颗粒微观形貌的变化,可以发现经过凹凸棒石改性后的石灰石颗粒表面仍留有较多的孔道,使其抗烧结能力得到大幅的提高。

Limestone as natural material can be used for Carbon dioxide （CO2） capture and sequestration （CCS） in flue gas effectively. However, its CCS capability will dramatically decline after several cycles due to the surface ＂ sintering＂. In this paper we modified the limestone with attapulgite to improve its CCS ability. As a kind of mineral with nano-fibrous structure, attapulgite can reduce the sintering phenomenon between the limestone particles which can improve the carbonation rate during the CCS process. The experimental results shown that the limestone modified with attapulgite and purified attapulgite can both improve the the carbonation rate, but limestone modified with purified attapulgite showed the better result. The morphology change of limestone with the modified of attapulgite were studied by SEM. We found that after modified with attapulgite the absorbent＇ s porous surface will be kept and the surface sintering was postponed.