摘要
目的研究H_(2)S/CH_(4)重整制氢反应过程中,Mo/Al_(2)O_(3)催化剂在高CH_(4)含量下的稳定性问题。方法分别采用簇状结构Al_(2)O_(3)(Cluster Al_(2)O_(3))和商业Al_(2)O_(3)(Com Al_(2)O_(3))为载体制备了Mo/Al_(2)O_(3)催化剂,考查在常压800℃、n(H_(2)S)∶n(CH_(4))=1∶5、体积空速20000 h-1的反应条件下,H_(2)S和CH_(4)的反应速率以及H_(2)生成速率随时间的变化;结合采用了SEM、XRD、HRTEM、BET、EA、TG、Raman以及NH 3-TPD、CO_(2)-TPD等多种表征分析手段与方法。结果与Mo/Com Al_(2)O_(3)催化剂相比,Mo/Cluster Al_(2)O_(3)催化剂具有更好的催化活性和稳定性,其H_(2)的初始生成速率达8.4 mmol/(g·min),为前者的3.8倍,20 h后的下降幅度也显著小于前者;Cluster Al_(2)O_(3)载体虽然比表面积较小,但所负载的活性MoS 2颗粒分散性更好,且能保持高温稳定。结论其原因可能与Cluster Al_(2)O_(3)表面拥有适宜的酸碱位强度及数量分布有关;同时,较小颗粒的MoS 2活性位更多,使得Mo/Cluster Al_(2)O_(3)催化剂在反应过程中表现更稳定,并能在一定程度上抑制CH_(4)裂解积炭。
Objective It is to research the problem that Mo/Al_(2)O_(3) catalyst is highly active for the reaction between H_(2)S and CH_(4) to produceH_(2),but couldn’t sustain a long term stability especially in a condition of high CH_(4)content.Methods Two kinds of Mo/Al_(2)O_(3) catalysts are compared in term of both H_(2)S and CH_(4)reaction rates and H_(2) generation rate varying with reaction time on stream under the conditions of 0.1 MPa,800℃,n(H_(2)S)∶n(CH_(4))=1∶5,and gas hourly space velocity of 20000 h-1;and the various characterization and analysis techniques and methods are also used with SEM,XRD,HRTEM,BET,EA,TG,Raman and NH 3-TPD/CO_(2)-TPD.Results The Mo/Cluster Al_(2)O_(3) catalyst prepared with the cluster structure Al_(2)O_(3) as the supporter has a better catalytic activity and stability than the Mo/Com Al_(2)O_(3) catalyst obtained with the commercial Al_(2)O_(3) supporter.The H 2 generation rate over the Mo/Cluster Al_(2)O_(3)catalyst reached 8.4 mmol/(g·min)in the initial reaction stage,which was 3.8 times of the Mo/Com Al_(2)O_(3)catalyst,and the decrease after 20 h is significantly less than the former;It is found that although the Cluster Al_(2)O_(3)supporter possessed a lower specific surface area,the dispersion of active MoS 2 particles supported on Cluster Al_(2)O_(3)is better and can make MoS 2 particles stabilized at high temperatures.Conclusions The reason could be assigned to the suitable acidic and alkaline strength and quantity distributions on the surface of Cluster Al_(2)O_(3).Meanwhile,smaller-particle MoS 2 has more edge-exposed active sites,which make Mo/Cluster Al_(2)O_(3)catalyst perform more stable during the H_(2)S/CH_(4)reforming reaction,and also can inhibit carbon deposition caused by CH_(4)cleavage to a certain extent.
作者
吴静贤
冯昊
王昊
周君尧
张文畅
张宏康
殷羽彤
李平
Wu Jingxian;Feng Hao;Wang Hao;Zhou Junyao;Zhang Wenchang;Zhang Hongkang;Yin Yutong;Li Ping(State Key Laboratory of Chemical Engineering,East China University of Science and Technology,Shanghai,China)
出处
《石油与天然气化工》
CAS
CSCD
北大核心
2022年第1期38-45,52,共9页
Chemical engineering of oil & gas
关键词
硫化氢
甲烷
重整制氢
簇状氧化铝
硫化钼
稳定性
hydrogen sulfide
methane
hydrogen production by reforming
cluster Al_(2)O_(3)
MoS 2
stability
