6.1.2. Hydrogen yield
The corresponding hydrogen yield profiles at different feed temperatures and S/C feed ratios are shown in Fig. 3. Very interesting results are shown in these figures. At a low S/C feed ratio of 1.0 the hydrogen membrane has a significant improvement of hydrogen yield at all feed temperatures (300 °C, 400 °C, 500 °C) as shown in Fig 3a1–c1. For the reformer with membrane (CFFBMR) the increase of the feed temperature from 300 °C to 400 °C has a more pronounced effect on the hydrogen yield than the increase of the feed temperature from 400 °C to 500 °C. Weak maximum points appear at a feed temperature of 500 °C as shown in Fig. 3c1. The locations of these maxima are at same locations of 100% conversion of heptane as shown in Fig. 2c1. Reaction (1) is the main source of hydrogen production and by its stoppage the reaction media have lost a key supplier of hydrogen. After the maximum point of the CFFBMR the hydrogen contributors are reactions (2), (3) and (4). The maximum point of the CFFBMR gives slight drop in the profile because reactions (2), (3) and (4) continue to supply hydrogen, while in the case of the reformer without hydrogen membrane a drastic drop in hydrogen yield occurs after the maximum point due to the consumption of hydrogen in reaction media till the equilibrium value is reached.