Nanofluid concept for enhancement of hydrogen utilization and gasoline production in fixed bed reactor Fischer—Tropsch synthesis of GTL (gas to liquid) technology

摘要

The present study proposes a novel configuration for cooling system of Fischer—Tropsch synthesis (FTS) reactor. In this new configuration, nanofluid is used as a coolant inside the shell of fixed bed reactor of FTS. This novel concept has been named nanofluid-cooled fixed bed reactor (NFR). Aqueous based nanofluids consist of alumina nanoparticles are used in the shell side of NFR while saturated water is used in the shell side of conventional reactor (CR) as a coolant. Various nanofluids with different concentrations have been examined and their effects on the reactor performance have been investigated. Heat transfer from tubes is improved in NFR reactor because of using aqueous based nanofluids containing alumina nanoparticles. Therefore tubes are increased in NFR reactor in comparison with CR. The simulation results consist of two schemes of NFR (various concentrations of alumina nanoparticles, NFR I, NFR II) and one scheme for CR. The results of different schemes are presented and they have been compared in terms of temperature, gasoline yield, CO2 yield, H2 conversion and CO conversion. The interesting result is decreasing temperature jump at the entrance of NFR reactor. Also using more tubes inside the shell of NFR I and NFR II causes not only decrease of temperature jump in the entrance of reactor but also increases hydrogen utilization and gasoline production. Hydrogen utilization shows an increase of 18% in NFR I and also 12% in NFR II in comparison with CR. Gasoline production shows an increase of 21% in NFR I and also 10% in NFR II in comparison with CR. The ratio of CO2 yield to gasoline yield is decreased to 2.12% in NFR I and 1.51% in NFR II in comparison with CR.