甘氨酸盐捕集二氧化碳后的矿化解吸与再生研究

Study on mineralization-desorption and regeneration of post-CO2 capture by glycine salt

矿化解吸作为低能耗的再生工艺已成为二氧化碳捕集封存(CCS)技术的关注点。为了更好地研究矿化解吸已捕集二氧化碳的吸收剂以及吸收剂再生的整个过程,采用了衰减全反射傅里叶变换红外光谱法(ATR-FTIR)指认了甘氨酸钾溶液以及其二氧化碳吸收饱和溶液的12个特征峰,再选定特有的反应物和产物的特征峰,对氧化钙矿化解吸已捕集二氧化碳以及甘氨酸钾再生过程做跟踪测量。实验结果表明,在矿化解吸二氧化碳过程中随着甘氨酸钾溶液pH的逐渐升高,溶液中质子胺(—NH3^+)、氨基甲酸酯(N—COO^-)和碳酸氢根(HCO3^-)的含量在逐渐减少,溶液中的胺基(—NH2)不断生成,甘氨酸钾吸收剂得到再生。虽然—NH3^+可以完全再生回—NH2,但部分N—COO^-还保留在吸收剂溶液中。因此,氧化钙矿化解吸无法完全再生已捕集二氧化碳的甘氨酸钾吸收剂。该结果有助于进一步了解矿化解吸已捕集二氧化碳吸收剂的反应机理和反应动力学。

As a low-energy regeneration process,mineralization-desorption has become the focus of carbon dioxide capture and storage(CCS)technology.In order to study the whole process of mineralization-desorption of CO2-rich absorbent and its regeneration,12 characteristic peaks of potassium glycine solution and its CO2 saturated absorption solution were assigned by ATR-FTIR.Then the characteristic peaks of reactants and products were selected and used to monitor the CaO mineralization-desorption of CO2 absorbed by potassium glycine solution and its regeneration.The experimental results showed that the contents of protonic ammonia(—NH3^+),carbamate(N—COO^-)and bicarbonate(HCO3-)decreased with the increase of the pH of the solution in the mineralization-desorption process.The amino content(—NH2)in the solution was continuously genera ted,indicating that the potassium glycine absorbent was regenerated.Although—NH3^+can completely regenerate back to—NH2,part of N—COO^-remains in the absorbent solution.Therefore,calcium oxide mineralization-desorption cannot completely regenerate the potassium glycine absorbent which had absorbed CO2.The results are helpful to further understand the reaction mechanism and kinetics of the CO2 absorbers that have been trapped in the mineralization-desorption process.