Ca(OH)2解吸并固定混合吸收液中CO2的实验研究

CO₂化学吸收法分离纯度高，技术成熟，但能耗过高及成本是困扰该技术发展的瓶颈.在常压条件下对利用Ca（OH）₂直接矿物碳酸化固定MDEA/PZ混合吸收富液中CO₂进行了一系列实验研究，考察了吸收液负荷、Ca（OH）₂投加量、pH、温度及搅拌速率等因素对解吸率的影响，并利用动态吸收-解吸循环实验研究了其CO₂吸收性能和循环使用稳定性，最后对碳酸化反应产物进行了XRD、TEM分析.结果表明，在常压条件下，Ca（OH）₂可以通过液相直接矿物碳酸化对CO₂进行直接固定，并实现吸收富液的再生；随着负荷的升高及Ca（OH）₂投加量、pH、搅拌速率的增大，解吸率随之增加；随着溶液温度升高，解吸率下降；经过5次动态吸收-解吸循环实验后CO₂吸收量可以达到并保持在0.57 mol·L^-1，显示出了良好的循环稳定性.

Experimental study on desorption and mineralization of CO2 in amine-rich solution

Chemical absorption is a mature technology with a feature of high separation purity. But it has bottlenecks of high energy consumption and cost, which hinder the development of this technology. To address these issues, calcium hydroxide, a fine desorption agent with low cost and energy saving, was selected to desorb and sequestrate CO₂ in the rich solution under atmospheric pressure. The effects of CO₂ loading, Ca(OH)₂ dosage, temperature, pH and stirring rate on the desorption rate were investigated. The dynamic absorption-desorption cycle experiment was used to study the CO₂ absorption performance and recycling stability. The characterization of carbonated products was also investigated applying XRD and TEM. The results showed that Ca(OH)₂ could be directly immobilized by direct mineral carbonation in liquid phase under normal pressure. With the increase of loading, Ca(OH)₂ dosage, pH and stirring rate, the desorption rate increased, while with the increase of solution temperature, the desorption rate decreased. After five dynamic absorption-desorption cycles, the capacity of CO₂ absorption reached and remained at 0.57 mol·L^-1, which showed good cyclic stability.