反应条件对Ni-CaO-ZrO_2催化剂上CH_4-CO_2重整反应及积炭的影响

Influences of reaction conditions on the CH_4-CO_2 reforming and coking properties of a Ni-CaO-ZrO_2 catalyst

用共沉淀法制备了Ni-CaO-ZrO2催化剂,并将其用于CH4-CO2重整反应。考察了反应温度、空速和反应物配比对催化剂性能和积炭的影响。通过热力学计算和实验表征研究发现,反应条件对CH4-CO2重整反应结果和积炭有重要的影响。由于高温条件同时有利于CH4裂解和碳物种的及时消除,升高温度可以提高催化剂的活性和稳定性。增大空速则使CH4的转化率和消碳反应的速率均降低,导致积炭量增加。同时,反应物配比对催化剂表面的积炭量也有很大影响;稍高的CO2/CH4摩尔比有利于抑制CH4-CO2重整反应过程中的积炭。

CH4-CO2 reforming was carried out over a Ni-CaO-ZrO2 catalyst prepared by co-precipitation.The influence of reaction conditions like temperature,space velocity and feed component on CH4-CO2 reforming and coking properties was studied.Thermodynamic calculation as well as experimental measurement indicated that the reaction conditions play an important role in the behaviors of reforming and coke deposition.Higher activity and stability are observed under higher temperature due to the enhancement of both CH4 decomposition and elimination of carbon species formed at such condition.At higher space velocity,both the conversion of CH4 and the rate of carbon elimination are decreased,resulting in an increase of carbon deposition.The component of feed gases also has a significant impact on the amount of carbon deposited;a higher CO2/CH4 molar ratio is favored in suppressing coking during the reforming reaction.