还原参数对F-T合成Fe-Mn催化剂物相结构的影响

Effect of Reduction Parameters on the Structure of Fe-Mn Catalyst for Fischer-Tropsch Synthesis

在浆态床反应器中研究了还原气氛和还原压力对微球状FT合成FeMn催化剂织构性质和物相结构变化的影响,结果表明以H2还原后的催化剂比表面积最大,而以合成气或CO还原时,因积炭堵塞孔道,导致催化剂比表面积大幅降低;随还原气氛中CO分压的增大,物相中铁碳化物含量增加,有利于催化剂的还原与碳化;当采用不同还原压力的合成气还原时,催化剂比表面积随还原压力的升高而下降,此外,较高的还原压力使反应器中H2O/H2比增大,导致催化剂中的部分铁碳化物再氧化,因此催化剂中的铁碳化物含量随着还原压力的升高先增加后减少。

The effects of reductants and reduction pressure on the textural properties and phase composition of the spherical Fe-Mn Fischer-Tropsch synthesis catalyst were investigated in a slurry reactor. It was found that the BET surface area of the H2-reduced catalyst is the biggest. The BET surface area of the catalyst monotonically decreased with the decrease of H2/CO ratio when syngas or CO was used as reductant, which can be due to the carbon deposition. The FexC content in the reduced catalysts increased with the decrease of H2/CO ratio. The BET surface area of catalysts decreased with the increase of reduction pressure, while the FexC content firstly increased and then decreased with the increase of the reduction pressure for syngas reducing. This trend might be ascribed to the high H2O/H2 ratio in the system at high reduction pressure which re-oxidized the iron carbide（s） formed during the reduction.