• 主题
高级搜索  >
历史搜索 清空历史
首页> 外文学位 >Dense mixed-conducting ceramic membrane reactor for oxidative coupling of methane.
【24h】

Dense mixed-conducting ceramic membrane reactor for oxidative coupling of methane.

机译：用于甲烷氧化偶合的致密混合导电陶瓷膜反应器。

获取原文
获取原文并翻译 | 示例
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Due to its promise for direct conversion of natural gas (90 vol% of methane) into C{dollar}sb2{dollar} (C{dollar}sb2{dollar}H{dollar}sb4{dollar} and C{dollar}sb2{dollar}H{dollar}sb6{dollar}) products, oxidative coupling of methane (OCM) has attracted tremendous interests and research efforts from both scientific and industrial communities since 1982. However, the C{dollar}sb2{dollar} yields achieved so far for OCM over any solid oxide catalysts in a conventional packed-bed reactor are less than 25% if the C{dollar}sb2{dollar} selectivity are maintained higher than 50%. This is generally believed to be caused by undesired gas phase combustion reactions in which methane and C{dollar}sb2{dollar} products are oxidized into CO{dollar}sb{lcub}rm x{rcub}{dollar}.; A novel dense oxygen semipermeable and catalytically active ceramic membrane reactor (DOS-CA-CMR) is used for OCM reaction in this work. This reactor has the potential to achieve higher C{dollar}sb2{dollar} yield and selectivity for OCM since the oxygen is directed supplied through the oxide solid phase. The mechanism of this reactor and the requirements for the membrane materials are discussed. The experimental work is devoted to the selection, fabrication and test of the suitable membrane materials for the OCM membrane reactor.; In order to search for a membrane material with high oxygen semipermeability, good OCM catalytic properties and high stability under OCM reaction conditions, a conventional packed-bed reactor operated in both cofeed and cyclic modes and a transient TGA measurement system are designed and used to evaluate the suitability of the selected materials (in powder or pellet form) for OCM. With this method it is found that two perovskite-type oxides, {dollar}rm Lasb{lcub}0.2{rcub}Srsb{lcub}0.8{rcub}CoOsb3{dollar} (LSC) and {dollar}rm SrCosb{lcub}0.2{rcub}Fesb{lcub}0.8{rcub}Osb3{dollar} (SCF), might not be suitable for OCM membrane reactor while 25 mol% yttria doped bismuth oxide (BY25) may exhibit good OCM catalytic properties when used in an OCM membrane reactor. It is concluded that the OCM catalytic properties of an oxide is closely related to its ionic and electronic conductivity. A material of good selectivity for OCM reactions may become non-selective as it transfers from a p-type electronic conductor to an n-type one. The oxygen permeation properties of LSC oxide is studied with the transient TGA measurement.; An OCM membrane reactor is designed, constructed and studied in this work. It is also used for the direct measurement of the oxygen permeation fluxes through ceramic membranes. Several membranes are studied in this reactor to test their OCM performance and oxygen permeation properties. Among them, {dollar}rm Smsb2Osb3{dollar} and {dollar}rm Ysb2Osb3{dollar} doped {dollar}rm Bisb2Osb3{dollar}(BYS) membrane exhibits both good OCM catalytic properties and stability under the reaction conditions. In order to achieve a high C{dollar}sb2{dollar} selectivity, the oxygen permeation flux must match with the OCM reaction rate. A high membrane surface to reactor volume ratio is essential to obtain a high C{dollar}sb2{dollar} yield in a dense OCM membrane reactor.
机译：由于其有望将天然气（甲烷的90 vol％）直接转化为C {dollar} sb2 {dollar}（C {dollar} sb2 {dollar} H {dollar} sb4 {dollar}和C {dollar} sb2 {自1982年以来，美元} H {dollar} sb6 {dollar}）产品，甲烷的氧化偶联（OCM）引起了科学界和工业界的极大兴趣和研究努力。但是，C {dollar} sb2 {dollar}的收率却如此如果将C {dollar} sb2 {dollar}的选择性保持在50％以上，则在常规填充床反应器中，相对于任何固体氧化物催化剂，OCM的最大收率都小于25％。通常认为这是由于不希望的气相燃烧反应引起的，其中甲烷和C {dollar} sb2 {dollar}产物被氧化成CO {dollar} sb {lcub} rm x {rcub} {dollar}。在这项工作中，新型的致密氧半渗透性和催化活性陶瓷膜反应器（DOS-CA-CMR）用于OCM反应。该反应器有潜力获得更高的CCM收率和OCM选择性，因为氧气直接通过氧化物固相供应。讨论了该反应器的机理和对膜材料的要求。实验工作致力于OCM膜反应器的合适膜材料的选择，制造和测试。为了寻找具有高氧气半渗透性，良好的OCM催化性能和在OCM反应条件下具有高稳定性的膜材料，设计了一种以共进料和循环模式运行的常规填充床反应器和一个瞬态TGA测量系统，并进行了评估。所选材料（粉末或颗粒形式）对OCM的适用性。用这种方法发现两种钙钛矿型氧化物，{美元} rm Lasb {lcub} 0.2 {rcub} Srsb {lcub} 0.8 {rcub} CoOsb3 {dollar}（LSC）和{美元} rm SrCosb {lcub} 0.2 {rcub} Fesb {lcub} 0.8 {rcub} Osb3 {dollar}（SCF）可能不适合OCM膜反应器，而25摩尔％氧化钇掺杂的氧化铋（BY25）在OCM膜中使用时可能表现出良好的OCM催化性能反应堆。结论是，氧化物的OCM催化性能与其离子和电子电导率密切相关。对于OCM反应具有良好选择性的材料可能会因为从p型电子导体转移到n型电子导体而变得非选择性。用瞬时TGA测量研究了LSC氧化物的氧渗透性能。在这项工作中，设计，构造和研究了OCM膜反应器。它也可用于直接测量通过陶瓷膜的氧气渗透通量。在该反应器中研究了几种膜，以测试其OCM性能和氧气渗透性能。其中，掺杂了{rms Bisb2Osb3 {dollar}（BYS）的{rms Smsb2Osb3 {dollar}和$ rm Ysb2Osb3 {dollar}（BYS）膜在反应条件下均具有良好的OCM催化性能和稳定性。为了实现高的C sb 2的选择性，氧气的渗透通量必须与OCM反应速率相匹配。高的膜表面反应器体积比对于在致密的OCM膜反应器中获得高的C {dollar} sb2 {dollar}收率至关重要。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号