再氧化温度及氧物种对正丁烷选择氧化的影响

Effects of Re-oxidation Temperature and Oxygen Species on n-butane Selective Oxidation to MA

在固定床微型反应器中 ,利用在线质谱动态响应技术 ,考察了VPO催化剂再氧化温度和不同氧物种对正丁烷选择氧化制顺酐 (MA)的影响。结果表明 ,VPO催化剂再氧化温度对非定态晶格氧选择氧化性能影响明显 ,其晶格氧是选择氧化的氧源 ,吸附氧是深度氧化的氧源 ,吸附氧与晶格氧可以相互转化。当正丁烷选择氧化和VPO催化剂再氧化在反应器内序贯、交替进行时 ,不仅可以通过改善催化剂再氧化条件使再氧化与正丁烷选择氧化条件恰当的匹配来改善时均反应性能 ,而且可通过提高VPO催化剂内可用晶格氧量和晶格氧的扩散速率来改善MA的选择性。

Effects of re oxidation temperature and oxygen species of vanadium phosphorous oxide (VPO) catalyst on n butane selective oxidation to maleic anhydride (MA) were experimentally studied using on line mass spectroscopy (MS) transient measurement in a fixed bed micro reactor. The results show that the re oxidation temperature of VPO catalyst is very important to n butane selective oxidation to MA operated under unsteady state mode. The lattice oxygen leads to selective oxidation, while adsorbed oxygen leads to complete oxidation. Adsorbed oxygen on the surface of the VPO catalyst can be transformed to lattice oxygen. By raising the re oxidation temperature of the catalyst to match selective oxidation and re oxidation of catalyst each other can remarkably improve the reaction performance of a CFB two bed system or a fixed bed in which the n butane selective oxidation and VPO catalyst re oxidation are performed periodically. And by increasing the diffusion rate of the lattice oxygen and usable lattice oxygen capacity in VPO catalyst can considerably improve the selectivity of MA.