高温下Ti掺杂对Li_4SiO_4吸收CO_2性能的影响  

Influence of Ti-doping on CO_2 Absorption by Li_4SiO_4 at High-temperatures

作　　者：汪文哲[1] 熊贵[2] 张军营[1] 赵永椿[1] 郑楚光[1] 

机构地区：[1]华中科技大学煤燃烧国家重点实验室,武汉430074 [2]华中科技大学电子科学与技术系,教育部敏感陶瓷工程研究中心,武汉430074

出　　处：《动力工程学报》2010年第8期623-627,共5页Journal of Chinese Society of Power Engineering

基　　金：国家自然科学基金资助项目(40972102,50936001);国家重点基础研究发展规划资助项目(2010CB227003)

摘　　要：采用固相合成法和溶胶凝胶法分别制备了可直接在高温下吸收CO2的硅酸锂(Li4SiO4),并进行了Ti的掺杂改性.采用X射线衍射仪、比表面积测定仪和热重分析仪对Li4SiO4进行了表征及CO2吸收性能的测试,并在固定床台架上进行了CO2循环吸收/解吸的试验研究.结果表明:溶胶凝胶法制备的纯Li4SiO4更有利于在高温下对CO2的吸收;CO2的分压对高温下Li4SiO4吸收CO2有很大影响,分压越大,吸收的CO2量越大;当TiO2的掺杂比例x=0.02时,改性的Li4SiO4对CO2的最大吸收量可达31.59%;经过20次循环后,固溶体Li4Si0.98Ti0.02O4对CO2的吸收量仅下降了20%,从第4次循环后此样品基本达到完全再生,说明其具有较大的CO2吸收量和优良的再生性能.Lithium orthosilicate（Li_4SiO_4） samples being able to directly absorb CO_2 at high-temperatures were prepared respectively by solid-state reaction and sol-gel method,some of which were improved by doping Ti element.The samples were characterized by X-ray diffraction,BET surface area and thermogravimetric analysis,while their CO_2 absorption capabilities measured,and corresponding cyclic CO_2 absorption/desorption studies performed on a fixed bed.Results show that at high temperatures,pure Li_4SiO_4 prepared by sol-gel method has stronger capability in CO_2 absorption,in which process partial pressure of CO_2 also plays an important role,i.e.the larger the partial pressure of CO_2,the more amount of CO_2 will be absorbed.For a doping proportion of TiO_2 x=0.02,the improved Li_4SiO_4 can result in an obvious weight change of CO_2 up to 31.59%,and after 20 absorption/desorption cycles,CO_2 absorption by Li_4Si_0.98Ti_0.02O_4 is to be reduced by only 20%.The samples can almost achieve complete regeneration from the 4th cycle,showing strong capabilities in CO_2 absorption and self-regeneration.

关 键 词：硅酸锂 CO2循环吸收/解吸 Ti掺杂 溶胶凝胶法 再生 

分 类 号：X511[环境科学与工程—环境工程]