TiO2掺杂 Na2 CO3／Al2 O3吸收剂在流化床中的 CO2捕集特性

摘要

由于 Na2 CO3／Al2 O3吸收剂的活性成分 Na2 CO3与 CO2反应活性较低，选用 TiO2作为掺杂剂，采用浸渍法将其添加到 Na2 CO3／Al2 O3吸收剂中进行改性，研制一种新型具有高反应活性的钠基固体吸收剂。利用小型流化床反应器进行了14次循环脱碳／再生试验，并对吸收剂进行了 XRD 和氮吸附表征。结果表明：掺杂 TiO2后，吸收剂与 CO2的反应速率加快，特别是在碳酸化反应的前10 min 内；反应前后除 TiO2外无其他含 Ti 化合物生成；碳酸化反应产物为 NaHCO3和 Na5 H3（CO3）4；14次循环反应后吸收剂仍保持稳定的微观结构。采用 XPS 和 FTIR 分析了 TiO2对 Na2 CO3／Al2 O3吸收剂脱碳特性的改性机理。%In order to improve the reactivity of Na2 CO3 /Al2 O3 sorbent with CO2 ,a new sorbent showing high reactivity was developed by doping Na2 CO3 /Al2 O3 with TiO2 using impregnation.Fourteen multi-cycle carbonation/regeneration tests of the sorbent were carried out in a fluidized-bed reactor and the sorbent was characterized by X-ray diffraction and nitrogen adsorption.It is confirmed that TiO2 shows a positive effect on the adsorption process of Na2 CO3 and the reaction rate is observed to increase significantly,especially in the first 10 min.Moreover,TiO2 is stable within the temperature range of the process and no other Ti-compounds are detected.The carbonation products are NaHCO3 and Na5 H3 (CO3 )4 .The surface area and the pore volume of the sorbent keep stable after 14 cycles.The Fourier transform infrared spectroscopy and the X-ray photoelectron spectroscopy are used to analyze the effect mechanism of TiO2 on CO2 adsorption process of Na2 CO3 /Al2 O3 .