天然气和二氧化碳转化制合成气的研究 Ⅶ.氧气的影响

Studies of reforming natural gas with carbon dioxide to produce synthesis gas VII. Effect of oxygen

采用固定床流动反应装置,考察了镍负载型催化剂上氧气对天然气和CO_2转化制合成气催化性能的影响,测定了催化剂的床层温度分布曲线.发现,随镍负载量增大,产物合成气摩尔百分含量迅速增大,当镍负载量达到一定值后,合成气含量保持不变.当原料气按化学计量比进料时,在800℃产物合成气的干基组成可以达到95%～96%(mol).氧气的加入对合成气含量影响较小,但可以在较宽范围(1.07～0.50)调节CO/H_2的比例.在800℃,CH_4:CO_2:O_2=35:35:17.5(ml/min)条件下,Ni-5催化剂连续使用280h,其活性和选择性几乎保持不变,说明催化剂具有良好的稳定性.在天然气和二氧化碳转化反应体系引入氧气,可以明显地缓和反应体系的强吸热效应,为降低能耗和增大反应器直径从而提高产量提供了可行性.

The effect of oxygen on catalytic activity of reforming natural gas with carbon dioxide to produce synthesis gas was studied by using a fix-bed flow apparatus. The temperature distribution a-long the catalyst bed was also measured. It is found that the addition of O2to the reaction system of natural gas and CO2would significantly decrease the endothermic effect. The thermal neutral reaction is almost achieved at CH4/CO2/O2= 1/1/0. 5. The molar ratios of CO to H2would be adjusted (CO/H2 = 1.07~0.5)by controlling CO2/O2ratios, which would realize significant economic benefits. The reaction results indicated that the Ni-5 catalyst was not deactivated during 280h on a stream with CH4/CO2/O2 = 35/35/17. 5rnl/min at 800℃. These results indicated that the Ni-5 catalyst has a high activity, selectivity and stability for the preparation of synthesis gas by conversion of CH4, CO2, O2.