在Co/SiO2作催化剂的Fischer-Tropsch反应中温度对合成气吸附行为及稳定性的影响

考察了反应温度对Co/SiO2催化剂在Fischer-Tropsch(F-T)合成中合成气吸附行为及稳定性的影响. 采用FTIR, TPSR, XRD, BET, HTPD和TPR等手段对催化剂进行了表征. 结果表明, CO在催化剂表面的吸附为活化吸附, 在270 ℃仍稳定存在, 随着反应温度的升高, 催化剂上发生的主反应由CO加氢链增长反应向Boudouard反应转化, 当反应温度≥350 ℃时, 以Boudouard反应为主. 另外, 随反应温度升高, 金属钴的烧结现象变得明显, 并伴随着硅酸钴或水合硅酸钴物种的生成. 在催化剂的失活因素中, 烧结为主要原因.

Effects of Temperature on Adsorption Behavior of Synthesis Gas and Stability for Co/SiO2 as Catalyst in Fischer-Tropsch Synthesis

The effects of temperature on adsorption behavior of synthesis gas and stability for Co/SiO2 catalyst in Fischer Tropsch synthesis(FTS) were studied by using FTIR, TPSR, XRD, BET, HTPD and TPR technologies. It was found that the CO adsorption was active on the surface of the catalyst and that was still stable at 270 ℃. With the reaction temperature increasing, the main reaction changed from the CO hydrogenation reaction to the Boudouard reaction, and the latter became overwhelming beyond 350 ℃. Besides, cobalt sintering became more evident accompanied with the formation of cobalt silicates and/or hydrosilicates species on the catalyst with the increase of the reaction temperature. It was also proved that sintering was the dominant reason for the catalyst deactivation at higher reaction temperature.