Reformed Exhaust Gas Recirculation Products of Rapeseed-based Biodiesel: A Chemical Equilibrium Simulation

AbstractThis paper simulates the products from an exhaust gas fuel reforming of rapeseed methyl ester (RME) in comparison with ultra-low sulphur diesel (ULSD). Both types of fuel were also correspondingly used as reformer fuels. In all cases, the reactor inlet temperature was kept constant at 300°C which represents exhaust gas temperature at low load engine condition and is comparable to the actual average exhaust gas temperature. The gas hourly space velocity (GHSV) was set-up at 30,000 h-1 and 45,000 h-1 whereas the latter is a half of typical value for automotive three-way catalytic converters. Different fuel flow rates between 25 and 55 ml×h-1 were tested. The reforming products and temperatures were calculated using an equilibrium model. The results have shown that different engine and reforming fuels affect the produced reformed gasses. Reforming of RME produced less hydrogen compared to the ULSD reforming. The results from simulation were compared with those from experiment at the same condition. At the higher GHSV, an offset between the measured experimental results and the predicted results from the equilibrium model has been found for all conditions tested. For the lower GHSV, the equilibrium model enables a good prediction in reforming yields of hydrogen

Mathematical modeling and performance study of Fischer-Tropsch synthesis of liquid fuel over cobalt-silica

AbstractA numerical one-dimensional pseudo-homogeneous mathematical model of a fixed bed reactor for Fischer-Tropsch (FT) synthesis was developed over a simulated nitrogen-rich syngas (33% hydrogen, 17% carbon monoxide and 50% nitrogen (volume basis)), on a cobalt-silica catalyst. An algorithm was developed and the MATLAB codes were written in order to predict the product selectivity (H2O, CO2 and hydrocarbons i.e. CH4, C2, C3, C4 and C5+) and syngas conversion (CO and H2). In order to predict the kinetic parameters, the global search optimization subroutine (from MATLAB Global Optimization) was used. The model was fitted with experimental data at five different operating conditions with respect to conversion and selectivity. Discrimination between the model and the experiments was determined by the mean absolute relative residuals percentage (MARR %) and the value was 13.29%. The Effects of operating conditions such as reaction temperature, total pressure, flow rate and H2/CO molar ratio were investigated on the catalytic performance of the cobalt-silica for synthesis of liquid fuel. The model was studied in the range of 200-260°C, 1-25bar, reduced gas flow rate (per unit mass of catalyst) of 2.4-3.6 NL gcat-1 h-1 and H2/CO = 1.75-2.75 (mole basis)