Mn/Al_2O_3脱氧剂的制备及表征

Preparation and characterization of Mn/Al_2O_3 deoxidizers

采用沉淀法制备了A12O3,并以之为载体利用浸渍法制备了Mn/A12O3脱氧剂。用XRD分别对A12O3和Mn/A12O3脱氧剂进行结构表征。通过与A12O3标准谱图对比,发现所制得载体为η-A12O3;脱氧剂XRD谱图上无明显的锰化合物特征峰,表明活性组分在载体上达到良好的单层分散。用TGA对η-A12O3和Mn/η-A12O3脱氧剂进行分析,载体和脱氧剂在制备条件下生成稳定的晶相。对制备的脱氧剂进行活性测试,在常压、入口氧浓度(N2中氧)600×10-6(体积分数)、空塔线速0.1m·s-1、脱氧温度200℃的条件下,脱氧容量达到33.9mlO2·g-1,尾气余氧量低于0.1×10-6(体积分数)维持10h以上。

A12O3 was prepared by precipitation method,and Mn/A12O3 deoxidizers were prepared by impregnation.A12O3 and Mn/A12O3 deoxidizers were characterized by powder X-ray diffraction(XRD).The carrier wasη-A12O3 by compared with A12O3 standard spectrogram;no obvious manganese compound characteristic peak on Mn/η-A12O3 deoxidizer XRD patterns,so that the active component was good monolayer dispersed in carrier.η-A12O3 and Mn/η-A12O3 deoxidizers were characterized by thermal gravimetry analysis(TGA).A stable crystalline phases was generated of the carrier and deoxidizers under the preparation condition.The deoxidizing activities were measured on a fixed-bed reactor with the reaction conditions as inlet oxygen concentration of 600×10-6(v/v),atmospheric pressure,linear velocity 0.1m·s-1,operation temperature 200℃.The deoxidizing capacity of Mn/η-A12O3 was 33.9mL·g-1,and residual oxygen in the exhaust gas was kept below 0.1×10-6(v/v)for 10hours.