Lu Plot and Yao Plot: Models To Analyze Product Distribution of Long-Term Gas-Phase Fischer–Tropsch Synthesis Experimental Data on an Iron Catalyst

Fischer–Tropsch synthesis (FTS) is a catalyzed chemical reaction in which synthesis gas (H2 + CO) is converted to clean fuels and chemicals. In addition to the classical Anderson–Schulz–Flory (ASF) model, two new models, namely, Yao and Lu models, are presented to show the FTS product distribution using the experimental data obtained in three fixed-bed reactors [each loaded with 1 g of the same iron-based catalyst and reduced with syngas (CO/H2), H2, and CO] over a wide range of FTS conditions. In the first approach, we plotted P(n + 1)/O(n + 1) versus Pn/On with carbon number n = 2–5, which is called Yao’s plot. The results showed that, although the P/O ratios are strongly dependent upon the process conditions, such as reduction agents, flow rates, pressures, etc., the plots of P(n + 1)/O(n + 1) against Pn/On yielded a nearly linear relationship, although with different gradients for all three reactors. These results indicate that the olefin and paraffin distributions are not independent. The current dat...