Li_2CuO_2高温吸附烟气CO_2的性能研究

Study on CO_2 adsorption of Li_2CuO_2 in the flue gas at high temperature

煤燃烧过程中排放大量CO_2是造成气候变化的原因之一,高性能CO_2吸附剂的制备是实现烟气高温脱碳的关键。以Li_2CO_3,LiOH和LiNO_3为Li源利用固相合成法制备出3种不同的Li_2CuO_2吸附剂,用于高温燃煤烟气CO_2捕集。通过X射线衍射(XRD)、场发射扫描电镜(SEM)、X射线光电子能谱(XPS)对比分析3种Li_2CuO_2的微观结构特征,利用热重分析仪(TGA)考察吸附剂烟气低体积分数下的捕碳性能,结合一阶反应模型研究吸附剂动力学特性。研究发现,Li_2CO_3制备出的Li_2CuO_2纯度高,晶体和颗粒粒径小,表面Li富集,使吸附反应速率快、捕获容量高,且动力学常数大,化学吸附过程需要的活化焓低,对温度依赖性小,更利于CO_2吸收。因此,Li_2CuO_2可在烟气温度下直接捕获CO_2,是一种有潜力的高温捕碳吸附剂。

CO 2 emission during coal combustion is one cause of climate change.The preparation of efficient CO 2 adsorbent is vital for capturing CO 2 from flue gas at high temperature.Li 2CO 3,LiOH and LiNO 3 were used to prepare Li 2CuO 2 sorbents for capturing CO 2 of coal combustion.The X-ray diffraction(XRD),scanning electron microscope(SEM)and X-ray photoelectron spectroscopy(XPS)were used to analyze the microstructure of three kinds of Li 2CuO 2.The thermal gravimetric analysis(TGA)was used to test the adsorption performance,and the kinetic characteristics of sorbents were analyzed by the first-order reaction model.The results show that Li 2CuO 2 made by Li 2CO 3 has higher purity,higher adsorption efficiency,smaller grain size and larger kinetic constant and the chemical adsorption process requires lower activation enthalpy,which is more conductive to CO 2 absorption.Therefore,Li 2CuO 2 is a potential high-temperature CO 2 adsorbent,which can capture CO 2 directly from flue gas at high temperature.