混合胺溶液耦合CaO吸收-矿化CO2特性及矿化过程关键影响因素研究

Study on CO2 absorption-mineralization characteristics of mixed amine solution coupled with CaO and key influencing factors in mineralization process

  • 摘要: 有机胺捕集CO2是一种有效的燃烧后碳捕集(PCC)技术,同时CO2矿物碳酸化是一种安全和稳定封存CO2的方法。本研究通过将两种方式结合,以MEA/MDEA混合胺溶液作为CO2吸收剂,以CaO作为CO2矿化原料,研究了不同混合胺溶液配比、温度、反应时间和CaO添加比例等条件下混合胺溶液耦合CaO吸收-矿化CO2性能。结果表明,在常温常压下CaO可对MEA/MDEA溶液中吸收的CO2进行有效矿化并同时实现MEA/MDEA溶液的再生;并且经过五次循环吸收-矿化实验后,MEA/MDEA溶液仍保持了较高的CO2转化率(77.4%)和CO2循环负荷(1.03 mol/L)。FT-IR和XRD表征分析表明,CaO的添加向MEA/MDEA溶液中提供了大量Ca2+和OH,可分别与溶液中的\rmCO_3^2- /\rmHCO_3^- 、质子化胺反应生成碳酸钙沉淀和游离胺,从而同时完成对CO2的矿化和MEA/MDEA溶液的化学再生;并且得到的固体产物主要成分为碳酸钙,方解石是其主要晶型。

     

    Abstract: Amine CO2 capture is an effective post-combustion carbon capture (PCC) technology, while CO2 mineral carbonation is a safe and stable method for CO2 storage. In this paper, these two methods were combined, and the CO2 absorption-mineralization performance of mixed amine solution coupled with CaO under different ratios of mixed amine solution, temperature, reaction time and CaO addition ratio were studied by using MEA/MDEA mixed amine solution as the CO2 absorbent and using CaO as the CO2 mineralizing raw material. The results show that CaO could effectively mineralize the CO2 absorbed in MEA/MDEA solution, realizing the regeneration of MEA/MDEA solution simultaneously under normal temperature and pressure. Meanwhile, the MEA/MDEA solution can still maintain a high CO2 conversion rate (77.4%) and CO2 cycle loading (1.03 mol/L) after five cycles of absorption-mineralization experiments. The FT-IR and XRD analyses reveal that the addition of CaO makes a large amount of Ca2+ and OH- into the MEA/MDEA solution, which could react with CO_3^2\rm - /HCO_3^\rm - and protonated amine in the solution to form calcium carbonate precipitate and free amine respectively, thus realizing the mineralization of CO2 and the regeneration of MEA/MDEA solution. The main component of solid products obtained is calcium carbonate, and calcite is its main crystal form.

     

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