(583dw) Effect of Syngas Flow Rate and Reaction Temperature On the Intrinsic Behavior of Fischer-Tropsch Synthesis On a Fixed-Bed Reactor

The effect of syngas flow rate and reaction temperature on Fischer-Tropsch synthesis (FTS) performance of the Co/γ-Al₂O₃ catalyst in a fixed-bed reactor was investigated. A heat exchanger type fixed-bed reactor was built to efficiently conduct the highly exothermic FTS reaction and obtain a constant reaction temperature while varying the reaction conditions. At 220 ^oC, the CO conversion decreased with increasing syngas flow rate to 200, 300 and 450 ml/min, and it finally decreased to zero at 450 ml/min because of the very short contact time (W_cat/F) of the hydrocarbon formation reactions. However, maximum values for C₅₊ selectivity, viz. 73%, and C₅₊ liquid oil productivity, viz. 0.096 g/(g_cath), were obtained at a syngas flow rate of 300 ml/min. Therefore, there was the optimum value of syngas flow rate for high C₅₊ liquid oil production and syngas superficial velocity (u_s) rather than contact time was the critical parameter for obtaining high C₅₊ liquid oil production. At the high temperature of 230 ^oC, CO conversion and C₅₊ liquid oil productivity increased to 45% and 0.118 g/(g_cath), respectively, compared to those obtained at 220 ^oC and 300 ml/min. Furthermore, CO conversion even at 450 ml/min was also 30%. Consequently, it was confirmed that temperature favored the kinetics of the FTS reactions, not only resulting in enhanced C₅₊ liquid oil productivity at the same syngas flow rate but also C₅₊ liquid oil production at short contact time.