| Abstract
| - CO2 hydrogenation on a K-promoted Fe catalyst was studied in a fixed-bed microreactor between300 and 400 °C, at 1 MPa, and with modified residence times in the range of 0.042−21.4 g·s/cm3. For temperatures below 360 °C, organic products almost identical with those found in thetraditional Fischer−Tropsch reaction with H2/CO were found (paraffins and α-olefins). At 400°C, formation of carbon deposited on the catalyst became a major reaction. Concerning themechanism of hydrocarbon formation, the effect of residence time resulted in catalyst particleselectivity values for hydrocarbons always higher than zero. This indicates that, besides thetwo-step reaction mechanism via CO, a direct hydrocarbon formation from CO2 can occur inprinciple. With a reaction scheme proposed from these experimental results, a kinetic modelwas developed using integration and regression features of ASPEN PLUS. Calculated valuesfor CO2 conversion and CO and total hydrocarbon selectivities agree with the experimental datawithin a range of error less than 15%.
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