还原温度对Fe-Mo催化剂性质及F-T合成性能的影响

Effect of reduction temperature on the properties and Fischer-Tropsch synthesis performance of Fe-Mo catalysts

研究了还原温度对Fe-Mo催化剂性质及费托(F-T)合成性能的影响。采用N2物理吸附、X射线衍射、穆斯堡尔谱和H2程序升温脱附技术对催化剂进行了表征。结果表明,随还原温度升高,金属铁晶粒粒径增大,金属铁上的H2吸附量先升后降;催化剂还原度提高,反应态催化剂碳化铁含量递增。催化剂F-T合成性能在280℃、1.5 MPa、2 000 h-1、合成气H2/CO比为2.0条件下在固定床反应器中测试。反应结果表明,随还原温度提高,催化剂接近稳态时的活性和重质烃选择性(C5+)先升后降,而甲烷选择性则先降后升。350℃还原催化剂具有最佳F-T合成反应性能。

Effects of reduction temperature on the properties and Fischer-Tropsch synthesis（FTS） performance of Fe-Mo catalyst were studied.Catalysts were characterized by N2 adsorption,X-ray diffraction（XRD）,Mssbauer effect spectroscopy（MES） and H2 temperature-programmed desorption（TPD）.The characterization results indicate that the crystallite size of metallic iron,the reduction degree and the carbide content（in catalysts after reaction） monotonously increase with increasing reduction temperature,while the amount of H2 chemisorption on metallic iron sites show a maximum at reduction temperature at 350 ℃.FTS performance was tested in a fixed-bed reactor at 280 ℃,1.5 MPa,2 000 h-1 and syngas H2/CO= 2.0.It is found that the steady-state FTS activity and the heavy hydrocarbons（C5＋） selectivity of the catalyst increase up to 350 ℃,and then decrease with further increasing reduction temperature.The catalyst redu at 350 ℃shows the optical FTS performance.