作　　者： ; ; ; ; ;

机构地区： 上海应用技术学院化工系化学工程系

出　　处： 《高校化学工程学报》 2008年第6期978-984,共7页

摘　　要： 以Li2CO3为锂源,制备了Li/TiO2膜,并用TG-DTA和XRD等技术对其进行了表征,由TG-DTA结果并结合XRD图谱可知,陪烧过程中发生了化学反应,并形成新的物相Li1.33Ti1.66O4。在YSZ固体氧化物电解质反应器中研究了甲烷在Li/TiO2膜上氧化偶联,考查了预混合、电化学两种方式供氧时甲烷分压、反应温度及停留时间等对甲烷转化速率、各产物生成速率和选择性等影响,比较了两种方式供氧时反应速率、目标产物选择性,并基于实验结果对反应机理进行了分析。结果表明,提高甲烷分压和反应温度对甲烷转化速率和目标产物选择性有利;提高预混合时氧分压或电化学供氧时的电流均能使反应速率增大,但CO2生成速率显著增加,导致目标产物选择性减小;在相同的反应温度、甲烷分压和氧通量条件下,电化学供氧时,催化剂膜上氧浓度较大而气相氧浓度较小,甲烷的转化速率及C2选择性明显大于预混合供氧。 Li/TiO2 film was prepared by impregnation method with Li2CO3 as Li source, and then the XRD and TG-DTA were adopted for the characterization of the prepared film. It was found that, during calcinations, chemical reaction between Li2CO3 and TiO2 takes place and forms a new compound of Li1.33Ti1.66O4° The oxidative coupling process of methane on Li/TiO2 film supported on yttria-stabilized zirconia was studied by using two different oxygen supply methods, the electrochemical oxygen supply and premixed oxygen supply, respectively. The effects of methane partial pressure, reaction temperature and time etc. on the methane conversion rate, products formation rate and selectivity of forming C2 hydrocarbons were investigated; the reaction mechanism was also analyzed. The results indicate that the higher methane partial pressure and higher reaction temperature benefit the methane conversion and the selectivity of forming C2 hydrocarbons; higher O2 pressure of premixed oxygen supply or higher the electric current density used for electrochemical O2 supply is advantageous to methane conversion but disadvantageous to the goal products selectivity which is caused by the much faster formation rate of carbon dioxide. It was also found that when using the electrochemical O2 supply method, the concentration of O2 on Li/TiO2 film is higher than the O2 concentration in the gas phase, therefore under the condition of having the same methane partial pressure, reaction temperature and the O2 flux, using electrochemical O2 supply method can get higher methane conversion rate and forming C2 hydrocarbons selectivity than those of using premixed O2 supply method.

关 键 词： 甲烷 氧化偶联 固体氧化物电解质 电化学供氧 预混合供氧

领　　域： [化学工程] [化学工程]